JP2017043011A - Manufacturing method of fiber-reinforced composite foam and thermoplastic resin foam particles usable for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a fiber-reinforced composite foam, which is excellent in the productivity.SOLUTION: The above-described problem is solved by a manufacturing method of a fiber-reinforced composite foam in which a fiber-reinforced resin material is disposed in a molding tool, thermoplastic resin foam particles having a bulk density of 0.015 to 0.6 g/are filled in the molding tool before or after the disposition or simultaneously therewith, then, by making foam the thermoplastic resin foam particles, the fiber-reinforced resin material and the resin foam are laminated and integrated to obtain a fiber-reinforced composite foam, the thermoplastic resin foam particles having the expandability of the following properties (1) and (2): (1) a thermal maximum expansion rate in a heating temperature range from room temperature to a melting point being 30 to 300%, and (2) the thermal expansion rate at any time point in the temperature range from a thermal expansion initiation temperature to a thermal maximum expansion rate being 5% by volume/min or higher (a value for unit time is obtained by heating for a predetermined time at each temperature, followed by dividing a volume change before and after the heating by the predetermined time).SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for producing a fiber-reinforced composite foam and thermoplastic resin foam particles that can be used in the method.

In recent years, resin materials reinforced with fibers (fiber reinforced resin materials) are lightweight and have high mechanical strength. Therefore, they are used for the bodies and interior materials of moving bodies such as vehicles, ships and aircraft, and for wind power generation. Opportunities for use in members that require high mechanical strength and light weight, such as wind turbine blades and housings of electronic devices, are increasing.
Further, in recent years, fiber reinforced resin materials have been required to have not only mechanical strength and light weight but also shock absorption.
Against this background, a fiber reinforced composite foam obtained by laminating and integrating a fiber reinforced resin material on the surface of a core material made of a resin foam has been used for the member.
That is, since the resin foam for forming the fiber reinforced composite foam (resin foam for forming the composite) has a lower density and better buffering properties than the fiber reinforced resin material, it is made of a fiber reinforced composite foam. The member is excellent in lightness and shock-absorbing property as compared with a member made entirely of a fiber reinforced resin material.
As a method for producing a fiber reinforced composite foam, for example, a method described in JP-A-63-162207 (Patent Document 1) is known.
That is, Patent Document 1 describes a fiber-reinforced composite foam obtained by heating and expanding a thermoelastic rigid foam obtained by a molding method of a composite sandwich core molding member.
JP 2002-292592 A (Patent Document 2) discloses a prepreg sheet in which a plurality of prepreg sheets each including a reinforcing fiber are laminated on at least a large part of the outer peripheral surface of a core material. A method for manufacturing a robot hand member is described which includes a step of forming a laminated body and a heating step of heating and thermosetting the laminated body to form a fiber reinforced resin member integrated with a core material.

JP-A 63-162207 JP 2002-292592 A

  In the above-mentioned patent document, after producing the core material, it takes a relatively long time until the thermosetting resin is cured, and it is difficult to sufficiently improve the production efficiency of the fiber-reinforced composite foam. Has a problem.

  The inventors of the present invention, by foaming foamed particles in a molding die in which the foamed particles and the fiber reinforced resin material are laid, thereby forming the resin foam (core material) and the fiber reinforced resin material and the resin foam. From the viewpoint that the above-mentioned problems can be solved by performing bonding and integration at the same time, the present invention has been achieved by earnestly researching thermoplastic resin foam particles for producing a fiber-reinforced composite foam suitable for foaming.

Thus, according to the present invention, the fiber reinforced resin material is arranged in the mold, and the foamed thermoplastic resin particles having a bulk density of 0.015 to 0.6 g / cm ³ are filled in the mold before or after the arrangement. Then, by foaming the thermoplastic resin foam particles, the fiber reinforced resin material and the resin foam are laminated and integrated to obtain a fiber reinforced composite foam.
The foamed thermoplastic resin particles have the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. Is a fiber-reinforced composite having a foaming property of 5 vol% / min or more (heating at each temperature for a predetermined time and dividing the volume change before and after heating by a predetermined measurement time to obtain per unit time) A method for producing a foam is provided.

Moreover, according to the present invention, the thermoplastic resin foam particles used in the method for producing the fiber-reinforced composite foam,
The foamed thermoplastic resin particles have the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. Is a fiber-reinforced composite having a foaming property of 5 vol% / min or more (heating at each temperature for a predetermined time and dividing the volume change before and after heating by a predetermined measurement time to obtain per unit time) A thermoplastic foam particle for forming a foam is provided.

ADVANTAGE OF THE INVENTION According to this invention, the thermoplastic resin foam particle which can manufacture easily the fiber reinforced composite foam excellent in productivity can be provided. Moreover, the manufacturing method of the fiber reinforced composite foam excellent in productivity can be provided.
Moreover, in any of the following cases, it is possible to provide thermoplastic resin foam particles that can easily produce a fiber-reinforced composite foam having higher productivity.
(1) The heating expansion start temperature is 50 ° C. or higher.
(2) The thermoplastic resin foamed particles contain 0.1 to 5.0% by mass of a foaming agent.

It is the schematic of the manufacturing apparatus of the fiber reinforced composite foam of this invention. It is the schematic of the nozzle part in the manufacturing apparatus of FIG. It is the schematic which showed the orientation of the fiber reinforced resin material which can be used for this invention. It is the schematic which showed the orientation of the fiber reinforced resin material which can be used for this invention. It is the schematic of the manufacturing process of the fiber reinforced composite foam of this invention.

(A) Method for Producing Fiber Reinforced Composite Foam Before and after placing fiber reinforced composite foam, fiber reinforced resin material is placed in a mold and foamable thermoplastic resin foam particles (hereinafter also referred to as foam particles) are placed. Or it fills in a shaping | molding die simultaneously, Then, it is obtained by foaming a thermoplastic resin expanded particle and laminating | stacking and integrating a fiber reinforced resin material and a resin foam.
The fiber reinforced composite foam can be used, for example, as a component for a mobile body such as a mobile phone, an electronic device housing such as a notebook computer, a portable music terminal, and a portable video device, a wind turbine blade, and a member for an automobile.

(Thermoplastic resin foam particles)
(A) Properties of expanded particles Expanded particles have the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. Is 5 vol% / min or more (heating at each temperature for a predetermined time and dividing the volume change before and after heating by a predetermined measurement time to obtain per unit time). Each measuring method of the heating maximum expansion rate and the heating expansion rate will be described in detail in the column of Examples.

  When the heating maximum expansion coefficient in the property (1) is less than 30%, the adhesion and integration between the fiber-reinforced resin material and the resin foam may be insufficient. If it is larger than 300%, the foam may be excessively foamed and the cell membrane may be broken to lower the strength. A preferable heating maximum expansion rate is 50 to 300%, and a more preferable heating maximum expansion rate is 70 to 250%. Here, in the measurement of the maximum heating expansion rate, the normal temperature as the starting point is about 25 ° C. The melting point is a value determined according to the type of thermoplastic resin used. Moreover, it is preferable that the difference of normal temperature and melting | fusing point is the range of 100-300 degreeC. Furthermore, it is preferable that the temperature which shows a heating maximum expansion rate is the range of 50-200 degreeC from melting | fusing point.

The heating expansion rate in the property (2) is to evaluate the heat fusion property between the foam particles and between the foam particles and the fiber reinforced resin material in order to obtain a fiber reinforced composite foam excellent in external accuracy and appearance. Used as an indicator of As the heating expansion rate, a larger value can give higher heat-fusibility.
When the heating expansion rate is less than 5% by volume / min, the thermal fusion property between the expanded particles may be lowered. A preferable heating expansion rate is 50% by volume / min or more, and a more preferable heating expansion rate is 80 to 200% by volume / min. The heating expansion start temperature is preferably 50 ° C. or higher. When the temperature is lower than 50 ° C., foaming starts during filling of the mold and the density becomes nonuniform, and the strength of the composite may be insufficient. The heating expansion start temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and particularly preferably 70 to 180 ° C. Moreover, it is preferable that the width | variety of the temperature range from a heating expansion start temperature to a maximum expansion coefficient is 5-100 degreeC.

  The expanded particles preferably have a maximum expansion pressure of 0.03 to 40 MPa within a heating temperature range from room temperature to the melting point. When the maximum expansion pressure is less than 0.03 MPa, the fiber reinforced resin material may not be pressed toward the mold with sufficient pressure when charged into the mold together with the fiber reinforced resin material. As a result, the surface smoothness of the fiber reinforced resin material of the resulting fiber reinforced composite foam is reduced, the fiber reinforced resin material cannot be molded into a desired shape, and the integration of the resin foam and the fiber reinforced resin material is insufficient. The mechanical strength of the resulting fiber-reinforced composite foam may be sufficient. When the maximum expansion pressure is larger than 40 MPa, the pressing force to the inner surface of the mold of the fiber reinforced resin material by the resin foam becomes too large, and the thermoplastic resin contained in the fiber reinforced resin material is more than necessary outside the mold. The fibers constituting the fiber reinforced resin material may be easily exposed to the outside. That is, if the foaming force of the foamed particles is too high than necessary, the surface smoothness of the resulting fiber-reinforced composite foam is lowered, the fiber-reinforced resin material cannot be molded into a desired shape, the resin foam and the fiber-reinforced resin material, The mechanical strength of the fiber-reinforced composite foam obtained by insufficient integration of the resin may be insufficient. A more preferable maximum expansion pressure is 0.1 to 40 MPa, and a further preferable maximum expansion pressure is 0.15 to 20 MPa.

  Adjustment of the heating maximum expansion rate and the heating expansion rate can be performed by the residual gas amount (foaming agent content), the skin thickness, the crystallinity of the surface layer, the apparent density, the open cell rate, and the like. For example, the maximum thermal expansion coefficient and the thermal expansion rate of the composite foam can be lowered by increasing the crystallinity of the surface layer. On the other hand, it can be increased by reducing the crystallinity of the surface layer.

  The crystallinity of the surface layer is preferably less than 24%. When the crystallinity is 24% or more, re-foaming at the time of heat fusion with the fiber reinforced resin material is hindered, and the fiber reinforced resin material may not be pressed against the inner surface of the mold with sufficient pressure. As a result, the fiber reinforced composite foam obtained has insufficient surface smoothness, the fiber reinforced resin material cannot be molded into a desired shape, and the fiber obtained by insufficient integration of the resin foam and the covering material The mechanical strength of the reinforced composite foam may be insufficient. A more preferable crystallinity is less than 23%, and a particularly preferable crystallinity is 10% or less.

  The crystallinity of the inner layer of the resin foam is preferably less than 24%. If the degree of crystallinity is too low, the resin foam may be too soft and the fiber reinforced resin material may not be pressed against the inner surface of the mold by sufficient re-foaming. Therefore, the crystallinity is more preferably 5 to 23%.

By using resin particles (foamed particles) foamed before filling as the particles to be filled in the mold, there are the following advantages.
(I) Since the expanded particles can be expanded and expanded at a high speed, the productivity of the composite can be improved.
(Ii) The foamed particles can be foamed at the same timing as the shaping / fusion of the resin foam and the fiber reinforced resin material.
(Iii) Since the internal pressure can be applied to the fiber reinforced resin material, the appearance of the fiber reinforced composite foam can be improved.

The expanded particles preferably have a bulk density of 0.015 to 0.6 g / cm ³ . When the bulk density is less than 0.015 g / cm ³ , the resin foam may become too soft, and the fiber reinforced resin material may not be pressed against the inner surface of the mold by sufficient re-foaming of the resin foam. As a result, the fiber reinforced composite foam has insufficient surface smoothness, the fiber reinforced resin material cannot be formed into a desired shape, and the fiber obtained by insufficient integration of the resin foam and the fiber reinforced resin material The mechanical strength of the reinforced composite foam may be insufficient. When the bulk density is larger than 0.6 g / cm ³ , the flexibility of the resin foam is lowered, and the resin foam may not be accurately re-foamed along the inner surface of the mold. As a result, the resin foam may not be able to press the fiber reinforced resin material accurately and sufficiently along the inner surface of the mold, and the resulting fiber reinforced composite foam may have insufficient surface smoothness, Integration with the fiber reinforced resin material may be insufficient, and the resulting fiber reinforced composite foam may have insufficient mechanical strength. A more preferable bulk density is 0.05 to 0.5 g / cm ³ , and a more preferable bulk density is 0.05 to 0.4 g / cm ³ .

The expanded particles preferably have an open cell ratio of less than 30%. When the open cell ratio is higher than 30%, the thermoplastic resin contained in the fiber reinforced resin material easily penetrates into the inside, so that the fiber reinforced resin material is excessive in order to achieve good adhesion with the fiber reinforced resin material. It may be necessary to carry a thermoplastic resin. In other words, if the open cell ratio of the resin foam is too high, it becomes easy to expose the fibers of the fiber reinforced resin material on the surface of the obtained fiber reinforced composite foam, and the surface smoothness of the fiber reinforced composite foam is deteriorated. May be sufficient. A more preferable open cell ratio is 20% or less, and a still more preferable open cell ratio is 10% or less.
The open cell ratio is adjusted by adjusting the foaming temperature for producing foamed particles and the amount of foaming agent supplied to the extruder when the resin foam is produced by in-mold foam molding of foamed particles. It can be carried out.

(B) Resin Constructing Expanded Particles The resin to be configured is not particularly limited as long as it includes a thermoplastic resin and can obtain expanded particles.
Examples of the thermoplastic resin include polyester resins, acrylic resins, polycarbonate resins, polymethacrylimide resins, polyolefin resins, and the like.
The thermoplastic resin does not need to be one kind alone and may be two or more kinds. The constituent resin may include rubber other than the thermoplastic resin (for example, an elastomer), a thermosetting resin (for example, an epoxy, an unsaturated polyester, a vinyl ester, etc.), and the like. It is preferable that the thermoplastic resin occupies 50% by mass or more of the constituent resin.

  The thermoplastic resin preferably has crystallinity. Since the thermoplastic resin having crystallinity can increase the crystallinity in the molding step, the heat resistance of the fiber-reinforced composite foam can be improved. As a method for adjusting the crystallinity, for example, the crystallinity of the surface layer of the expanded particles can be increased by slowing the cooling rate of the expanded particles immediately after expansion. Further, the crystallinity of the expanded particles can be lowered by increasing the cooling rate of the resin foam immediately after expansion. On the other hand, when the resin foam is produced by in-mold foam molding, the pressure of the heat medium flowing into the mold is reduced, and the heating of the foam particles filled in the mold is suppressed, so that the resin foam crystals The degree of conversion can be lowered.

The thermoplastic resin is preferably a polyester-based resin or an acrylic-based resin in order to exhibit excellent mechanical strength and shock absorption in the fiber-reinforced composite foam to be produced.
Examples of polyester resins include linear polyesters obtained by condensation reaction of polyvalent carboxylic acids and polyhydric alcohols.
Specific polyester resins include aromatic polyester resins and aliphatic polyester resins such as polylactic acid resins.

(B-1) Aromatic polyester-based resin The aromatic polyester-based resin is usually a polyester containing an aromatic polyvalent carboxylic acid component and a polyhydric alcohol component. For example, polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene. Examples include terephthalate resin, polycyclohexanedimethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene naphthalate resin. In addition, an aromatic polyester resin may be used independently or 2 or more types may be used together.
Examples of aromatic polycarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, tricarboxylic acids such as trimellitic acid, tetracarboxylic acids such as pyromellitic acid, and anhydrides thereof. Diols such as ethylene glycol, triols such as glycerin, and tetraols such as pentaerythritol.

The aromatic polyester resin is preferably a polyethylene terephthalate resin. The aromatic polyester resin may be a recycled material collected and recycled from a used PET bottle.
The aromatic polyester resin may be partially cross-linked as long as it is within a range where thermoplasticity is exhibited. Examples of the crosslinking agent for partial crosslinking include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, and oxazine compounds. In addition, a crosslinking agent may be used independently or 2 or more types may be used together.

The partially cross-linked aromatic polyester resin can be obtained by supplying a non-cross-linked aromatic polyester resin and a cross-linking agent to an extruder and dynamically cross-linking in the extruder.
The crosslinking agent is preferably used in an amount of 0.01 to 5 parts by mass with respect to 100 parts by mass of the non-crosslinked aromatic polyester resin. When the amount of the crosslinking agent is less than 0.01 parts by mass, the melt viscosity of the partially crosslinked aromatic polyester resin may be insufficient. As a result, foam breakage may occur during the formation of the resin foam. When the amount of the crosslinking agent is more than 5 parts by mass, the melt viscosity of the aromatic polyester resin becomes too high, and extrusion foaming may be difficult. A more preferable amount of the crosslinking agent is 0.1 to 1 part by mass.

(B-2) Polylactic acid-based resin As the polylactic acid-based resin, a resin obtained by polymerizing lactic acid with an ester bond can be used. From the viewpoint of commercial availability and ease of imparting foamability, the polylactic acid resin is a copolymer of D-lactic acid (D-form) and L-lactic acid (L-form), D-lactic acid or L-lactic acid. A ring-opening polymer of one or two or more lactides selected from the group consisting of any one of the following polymers, D-lactide, L-lactide and DL-lactide is preferable. In addition, polylactic acid-type resin may be used independently, or 2 or more types may be used together.

  The polylactic acid-based resin may contain an aliphatic polyhydric alcohol as a monomer component other than lactic acid. Examples of the aliphatic polyhydric alcohol include aliphatic hydroxycarboxylic acids such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxyheptanoic acid; succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid Aliphatic polycarboxylic acids such as succinic anhydride, adipic anhydride, trimesic acid, propanetricarboxylic acid, pyromellitic acid, pyromellitic anhydride; ethylene glycol, 1,4-butanediol, 1,6-hexanediol, Examples include 1,4-cyclohexanedimethanol, neopentyl glycol, decamethylene glycol, glycerin, trimethylolpropane, and pentaerythritol.

The polylactic acid-based resin may have a functional group such as an alkyl group, a vinyl group, a carbonyl group, an aromatic group, an ester group, an ether group, an aldehyde group, an amino group, a nitrile group, or a nitro group.
The polylactic acid-based resin may be crosslinked with an isocyanate-based crosslinking agent or the like, and may have a bond other than an ester bond in the main chain or side chain.

(B-3) Acrylic Resin Examples of the acrylic resin include a polymer of (meth) acrylic monomers. Here, “(meth) acryl” means “acryl” or “methacryl”.
(Meth) acrylic monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid 2- Examples include ethylhexyl, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, and (meth) acrylamide.

  The acrylic resin may contain a polymer component of another monomer copolymerizable with the (meth) acrylic monomer. Examples of such other monomers include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, maleic amide, maleic imide and the like.

(C) Other component which comprises foamed particle It is preferable that the foamed particle contains 0.1-5.0 mass% foaming agent. When the foaming agent is contained within this range, the foamed particles are re-foamed during the production of the resin foam, whereby excellent adhesiveness with the fiber reinforced resin material can be exhibited. When the content of the foaming agent is less than 0.1% by mass, the fiber reinforced resin material may not be pressed against the inner surface of the mold with sufficient pressure due to re-foaming of the resin foam. As a result, the smoothness of the obtained fiber reinforced composite foam on the surface of the fiber reinforced resin material becomes insufficient, the fiber reinforced resin material cannot be molded into a desired shape, and the integration of the resin foam and the fiber reinforced resin material is inadequate. The mechanical strength of the fiber reinforced composite foam obtained when sufficient may be insufficient. If it is larger than 5.0% by mass, the pressing force of the resin foam on the inner surface of the molding die of the fiber reinforced resin material may become too large. As a result, the thermoplastic resin contained in the fiber reinforced resin material flows out of the mold more than necessary, and the fibers constituting the fiber reinforced resin material are easily exposed to the outside, and the resulting fiber reinforced The surface smoothness of the composite foam may be reduced. A more preferable content is 0.5 to 3% by mass.

The foaming agent may be a chemical foaming agent or a physical foaming agent. Among these, those that are less likely to dissipate from the resin foam particles over time and that allow the resin foam to easily exhibit a predetermined foaming force when the resin foam is heated are preferable.
Examples of the chemical foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, hydrazoyl dicarbonamide, sodium bicarbonate and the like. A chemical foaming agent may be used independently or 2 or more types may be used together.

  Examples of the physical foaming agent include saturated aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane and hexane, ethers such as dimethyl ether, methyl chloride, 1,1,1,2-tetrafluoroethane, Examples include CFCs such as 1,1-difluoroethane and monochlorodifluoromethane, carbon dioxide, nitrogen, and the like. The physical foaming agent is preferably dimethyl ether, propane, normal butane, isobutane or carbon dioxide, more preferably propane, normal butane or isobutane, particularly preferably normal butane or isobutane. When the foamed particles are mainly composed of a polyester resin or an acrylic resin, the foaming agent is preferably normal butane, isobutane, or carbon dioxide. A physical foaming agent may be used independently or 2 or more types may be used together.

The amount of the remaining foaming agent in the foamed particles is, for example, (1) a method of increasing the amount of the remaining foaming agent in the foamed particles by increasing the amount of foaming agent mixed in the synthetic resin during production of the resin foam by extrusion foaming, ( 2) A method of increasing the amount of the remaining foaming agent in the resin foam by increasing the amount of the foaming agent impregnated in the foamed particles used in the production of the resin foam by in-mold foam molding, (3) Resin foaming A method of further impregnating the foam with a foaming agent to increase the amount of the remaining foaming agent in the resin foam, and (4) a residual foaming agent in the resin foam by reducing heating for foaming during the production of the resin foam. It can be controlled by a method such as a method of increasing the amount, or a method of reducing the amount of residual foaming agent in the resin foam by providing a curing step such as (5) placing the resin foam in a heated atmosphere for a certain time.
Other components than the foaming agent include plasticizers, flame retardants, flame retardant aids, antistatic agents, spreading agents, air conditioners, fillers, colorants, weathering agents, anti-aging agents, lubricants, anti-fogging agents. Agents, fragrances and the like.

(D) Shape of expanded particles The shape of expanded particles is not particularly limited. For example, spherical shape, cylindrical shape, etc. are mentioned. Of these, it is preferable that the shape be as spherical as possible. The expanded particles preferably have an average particle diameter of 0.5 to 5 mm.
The foamed particles preferably have a skin thickness of 0.01 to 0.5 mm. The skin thickness is more preferably 0.01 to 0.2 mm, and particularly preferably 0.015 to 0.2 mm. The skin thickness can be controlled by adjusting the extrusion resin temperature, the cooling water temperature, and the storage temperature immediately after production of the expanded particles. The lower the temperature, the higher the tendency for the skin thickness to increase.

(E) Manufacturing method of expanded particle As a manufacturing method of expanded particle,
(1) A thermoplastic resin is supplied into an extruder, melted and kneaded in the presence of a physical foaming agent, cut from the nozzle mold attached to the extruder while extruding the extruded product, and then cooled to expand the expanded particles. (2) A thermoplastic resin is supplied into an extruder, melt-kneaded in the presence of a physical foaming agent, and extruded and foamed from a nozzle die attached to the extruder to produce a strand-like foamed extrudate. A method of producing foamed particles by cutting the foamed extrudate at predetermined intervals (3) An annular attached to the extruder by supplying a thermoplastic resin into the extruder, melt-kneading in the presence of a physical foaming agent Method of producing foamed sheet by extrusion foaming from die or T-die, and cutting the foamed sheet (4) Making thermoplastic resin particles by suspension polymerization and impregnating foaming agent with autoclave Freshly foamable (5) A method of producing foamed particles by heating and foaming using a pre-foaming machine capable of supplying a heat medium such as water vapor after the child is manufactured. A strand-like extrudate is produced by extruding from a nozzle mold attached to the resin, and the extrudate is cut at predetermined intervals to produce resin particles, which are impregnated with a foaming agent in an autoclave to produce expandable particles. Thereafter, a method of producing foamed particles by heating and foaming using a pre-foaming machine capable of supplying a heat medium such as water vapor may be mentioned.

An example of a manufacturing apparatus that can be used in the manufacturing method (1) will be described with reference to FIGS.
Here, FIG. 1 shows a state in which foamed particles containing a foaming agent are produced using an extruder and a nozzle mold 1 attached to the front end thereof.
As shown in FIG. 2, a plurality of nozzle outlet portions 11 are formed on the same virtual circle A at equal intervals on the front end surface 10 of the nozzle mold 1.
At the portion surrounded by the nozzle outlet 11 on the front end face 10 of the nozzle mold 1, the rotating shaft 2 is disposed in a state of protruding forward. The rotary shaft 2 is connected to a drive member 3 such as a motor through a front portion 41a of a cooling drum 41 constituting a cooling member 4 described later.

Further, one or a plurality of rotary blades 5 are integrally provided on the outer peripheral surface of the rear end portion of the rotary shaft 2. All the rotary blades 5 are always in contact with the front end face 10 of the nozzle mold 1 during the rotation.
When a plurality of rotary blades 5 are integrally provided on the rotary shaft 2, the plurality of rotary blades 5 are arranged at equal intervals in the circumferential direction of the rotary shaft 2.

In FIG. 2, as an example, a case where four rotary blades 5 are integrally provided on the outer peripheral surface of the rotary shaft 2 is shown.
When the rotary shaft 2 rotates, the rotary blade 5 moves on the virtual circle A in which the nozzle outlet portion 11 is formed while constantly contacting the front end surface 10 of the nozzle mold 1, and the nozzle outlet The foamed extrudate extruded from the portion 11 is configured to be capable of being sequentially and continuously cut.
A cooling member 4 is disposed so as to surround at least the front end portion of the nozzle mold 1 and the rotating shaft 2. The cooling member 4 has a front circular front part 41a having a diameter larger than that of the nozzle mold 1 and a cylindrical peripheral wall part 41b extending rearward from the outer peripheral edge of the front part 41a. A bottom cylindrical cooling drum 41 is provided.

Further, a supply port 41c for supplying the coolant 42 is formed in a portion of the peripheral wall portion 41b of the cooling drum 41 corresponding to the outside of the nozzle mold 1 so as to penetrate between the inner and outer peripheral surfaces. Yes.
A supply pipe 41 d for supplying the coolant 42 into the cooling drum 41 is connected to the outer opening of the supply port 41 c of the cooling drum 41.
The coolant 42 is configured to be supplied obliquely forward along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 through the supply pipe 41d.
Then, the cooling liquid 42 spirals along the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41 by the centrifugal force accompanying the flow velocity when being supplied from the supply pipe 41d to the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41. Go forward as you draw.

The coolant 42 gradually spreads in the direction orthogonal to the traveling direction while traveling along the inner peripheral surface of the peripheral wall portion 41b. As a result, the inner peripheral surface of the peripheral wall portion 41 b in front of the supply port 41 c of the cooling drum 41 is completely covered with the cooling liquid 42.
The coolant 42 is not particularly limited as long as the foamed particles can be cooled, and examples thereof include water and alcohol. Of these, water is preferable in view of the treatment after use.
As a temperature of a cooling fluid, 5-40 degreeC is preferable. When it is less than 5 ° C., the mold temperature is remarkably lowered, and extrusion may become unstable. When the temperature is higher than 40 ° C., the foamed particles are insufficiently cooled, the open cell ratio is increased, and the foaming power at the time of compounding may be reduced. In addition, the non-foamed or high-density skin on the surface of the foamed particles becomes thin, and the foaming power at the time of compositing may be reduced. The temperature of the cooling liquid is more preferably 8 to 30 ° C, particularly preferably 10 to 35 ° C.

A discharge port 41e is formed on the lower surface of the front end portion of the peripheral wall portion 41b of the cooling drum 41 so as to penetrate between the inner and outer peripheral surfaces.
A discharge pipe 41f is connected to the outer opening of the discharge port 41e.
The expanded particles and the coolant 42 can be continuously discharged through the discharge port 41e.
A nozzle attached to the front end of the extruder after a thermoplastic resin (preferably together with a crosslinking agent) is supplied to the extruder and melt-kneaded in the presence of a foaming agent (the thermoplastic resin is preferably crosslinked with a crosslinking agent) Foamed particles can be produced by cutting the foamed extrudate obtained by extruding and foaming the thermoplastic resin from the mold 1 with the rotary blade 5.

(F) Preheating of expanded particles and fiber reinforced resin material The expanded particles may be preheated before being put into a mold. By preheating, the foamed particles put into the mold can be foamed at an early stage, and the foaming start timing can be adjusted. The preheating temperature is preferably a glass transition point (Tg) −50 to Tg + 50 ° C. of the resin constituting the expanded particles. If the preheating temperature is too low, the influence on the start of foaming may be reduced. If it is too high, foaming may start. The preheating temperature is more preferably Tg-40 to Tg + 40 ° C, and particularly preferably Tg-30 to Tg + 30 ° C. As the preheating device, for example, an infrared heater, a carbon heater, a hot air dryer, a heating plate, a band heater, a cartridge heater, or the like can be used.

  The fiber reinforced resin material may also be preheated like the foamed particles. By preheating, in the case of a fiber reinforced resin material containing a thermosetting resin, the thermosetting can be accelerated, and the viscosity of the thermosetting resin can be increased to improve the moldability and appearance. In the case of a fiber reinforced resin material containing a thermoplastic resin, it is possible to improve the fusibility to a resin foam and to improve productivity. The preheating temperature is preferably a glass transition point (Tg) −100 to Tg + 100 ° C. in the case of a thermosetting resin, and is preferably a glass transition point (Tg) +100 to Tg + 350 ° C. in the case of a thermoplastic resin. If the preheating temperature is too high, curing will start in the case of a thermosetting resin, and the fusibility to a resin foam will be reduced. In the case of a thermoplastic resin, the viscosity of the resin will be low, and fiber reinforcement will occur. Appearance may deteriorate due to the resin dripping from the resin material. If the temperature is too low, not only will the heating time after the mold has been charged be extended, but the fusing property to the resin foam may be reduced. In the case of a thermosetting resin, the preheating temperature is more preferably Tg-50 to Tg + 80 ° C., and in the case of a thermoplastic resin, the preheating temperature is more preferably Tg + 150 to Tg + 300 ° C. As the heating device, for example, an infrared heater, a carbon heater, a hot air dryer, a heating plate, a band heater, a cartridge heater, or the like can be used.

(Fiber reinforced composite foam)
In the fiber reinforced composite foam, a fiber reinforced resin material and a resin foam are laminated and integrated.
(A) Fiber-reinforced resin material The fiber-reinforced resin material is composed of a fiber component and a resin component.
(A-1) Fiber component Examples of the fiber component include inorganic fibers such as glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, Tyranno fiber, basalt fiber, and ceramic fiber; metal fibers such as stainless fiber and steel fiber; Examples include organic fibers such as aramid fibers, polyethylene fibers, and polyparaphenylene benzoxador (PBO) fibers; and components derived from fibers such as boron fibers. Since the fiber has excellent mechanical strength and heat resistance, carbon fiber, glass fiber, and aramid fiber are preferable, and carbon fiber is more preferable.

The fiber component may be dispersed in a granular form in the fiber reinforced resin material, or may be present in the form of a sheet. Among these, from the viewpoint of improving the strength of the fiber reinforced resin material, a sheet shape is preferable. Sheet-like forms include woven fabrics (for example, woven fabrics such as plain weaves, twill weaves, satin weaves, etc.), knitted fabrics, nonwoven fabrics, and bundles (sutures) of yarns of fiber bundles (strands) in which reinforcing fibers are aligned in one direction. Is mentioned.
The sheet-like fiber component may consist of only one fiber layer, or may be a laminate of a plurality of fiber layers. As a laminate of a plurality of fiber layers,
(1) A laminate obtained by preparing a plurality of sheet-like fiber layers made of only one kind of fiber and laminating them (2) A plurality of sheet-like fiber layers made of a mixture of a plurality of kinds of fibers Prepared and laminated (3) obtained by laminating them Prepare a plurality of sheet-like fiber layers composed of bundles, and stack them so that the fiber directions of the fiber bundles are different from each other For example, a laminated body obtained by integrating (stitching) the bundles that are combined and superposed with each other with a thread may be used. Examples of the yarn include synthetic resin yarns such as polyamide resin yarns and polyester resin yarns, and stitch yarns such as glass fiber yarns.

In the above (1), in the case of a laminate of a plurality of woven fabrics, it is preferable that the length direction of the warp (weft) constituting each woven fabric is arranged radially when viewed from the plane direction of the woven fabric.
Specifically, as shown in FIGS. 3 and 4, when the length directions of the warps (wefts) constituting each woven fabric are 1a, 1b,..., The lengths of these warps (wefts) It is preferable that the length directions 1a, 1b,. Further, when the length direction 1a of any warp (weft) of the warp (weft) length directions 1a, 1b... Is specified, the length direction 1a of the specific warp (weft) is the center. More preferably, the other warps (wefts) are arranged so that the length directions 1b, 1c, 1d,...

  Further, the crossing angle between the length directions 1a, 1b,... Of the warps (wefts) constituting each woven fabric is substantially the same in any direction without the strength of the fiber reinforced resin material being biased in one direction. Can give strength. Therefore, 90 ° is preferable when two woven fabrics are overlapped, and 45 ° is preferable when three or more woven fabrics are overlapped.

In the above (2), in the case of a laminate of fiber layers composed of a mixture of a plurality of types of fibers, the length direction of the fibers of the fiber bundle constituting each fiber layer is arranged radially when viewed from the plane direction of the fiber layer. It is preferable. Specifically, as shown in FIG. 3 and FIG. 4, when the length directions of the fibers of the fiber bundle constituting each fiber base are 1a, 1b. It is preferable that the directions 1a, 1b,... Are arranged radially, and when the arbitrary length direction 1a of the fiber length directions 1a, 1b,. More preferably, the other length directions 1b, 1c, 1d,... Are arranged so as to be line symmetric with respect to the center.
In addition, the crossing angle between the fiber length directions 1a, 1b,... Is that the strength of the fiber reinforced resin material is not biased in one direction, and can impart substantially the same mechanical strength in any direction. When two sheets are overlapped, 90 ° is preferable, and when three or more fiber base materials are stacked, 45 ° is preferable.
The trade name “Pyrofil” of Mitsubishi Rayon Co., Ltd. can also be used as a fiber base material.

(A-2) Resin component A fiber-reinforced resin material can be obtained by impregnating the fiber with a resin. Since the reinforcing fibers are bonded and integrated by impregnating the resin, the fiber-reinforced resin material has a strength superior to that of only the fiber component or the resin alone. As the resin, a thermosetting resin and a thermoplastic resin are usually used.
The thermoplastic resin is not particularly limited, and examples thereof include olefin resins, polyester resins, thermoplastic epoxy resins, amide resins, thermoplastic polyurethane resins, sulfide resins, and acrylic resins. In addition, a thermoplastic resin may be used independently or 2 or more types may be used together.

  The main resin in the resin component is preferably a polyester resin or a thermoplastic epoxy resin because it is excellent in adhesiveness with a resin foam or adhesiveness between reinforcing fibers constituting a fiber reinforced resin material. The main resin may be a thermoplastic elastomer such as a thermoplastic polyurethane resin. Here, the “main resin” means a resin contained in the highest mass ratio excluding the fiber component.

The epoxy resin is a polymer or copolymer of epoxy compounds and having a linear structure, or a copolymer of an epoxy compound and a monomer that can be polymerized with this epoxy compound. Examples include a copolymer having a chain structure.
Specifically, as the epoxy resin, for example, bisphenol A type epoxy resin, bisphenol fluorene type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, cyclic aliphatic type epoxy resin, long chain aliphatic type epoxy resin , Glycidyl ester type epoxy resin, glycidyl amine type epoxy resin and the like. Of these, bisphenol A type epoxy resins and bisphenol fluorene type epoxy resins are preferred.
In addition, an epoxy resin may be used independently or 2 or more types may be used together.

Examples of the polyurethane resin include polymers having a linear structure obtained by polymerizing diol and diisocyanate.
Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, and the like.
Diols may be used alone or in combination of two or more.
Examples of the diisocyanate include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate. Diisocyanate may be used independently or 2 or more types may be used together. In addition, a polyurethane resin may be used independently or 2 or more types may be used together.

  Examples of amide resins include hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl). Aliphatic, alicyclic and aromatic diamines such as cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xylylenediamine and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid Manufactured from aliphatic, alicyclic and aromatic dicarboxylic acids such as isophthalic acid, and aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid Resin, ε-caprolactam, resin produced from lactam such as ω-dodecalactam And a copolymer resin composed of these components, a mixture of these resins, and the like.

  Specifically, polycoupleramide (polyamide 6), polydodecanoamide (polyamide 12), polyhexamethylene adipamide (polyamide 6 · 6), polyhexamethylene azelamide (polyamide 6 · 9), polyhexamethylene sebaca Amide (polyamide 6 · 10), polyhexamethylene dodecanoamide (polyamide 6 · 12), polyxylylene adipamide, polyhexamethylene terephthalamide, polyphenylene phthalamide, polyamide 6/6 · 6, poly (xylylene) Adipamide / hexamethylene adipamide) and the like.

The resin component may further contain a thermosetting resin.
The thermosetting resin is not particularly limited. For example, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, maleimide resin and cyanide Examples thereof include a resin obtained by prepolymerizing an acid ester resin. Of these, epoxy resins and vinyl ester resins are preferred because of their excellent heat resistance, elastic modulus, and chemical resistance. A thermosetting resin may be used independently or 2 or more types may be used together.

The resin component content in the fiber reinforced resin material is preferably 20 to 70% by mass. When the content is less than 20% by mass, the adhesion between the reinforced fibers and the adhesion between the fiber reinforced resin material and the core material become insufficient, and the mechanical strength of the fiber reinforced resin material and the fiber reinforced composite foam Mechanical strength or shock absorption may not be sufficiently improved. Moreover, when more than 70 mass%, the mechanical strength of a fiber reinforced resin material may fall, and the mechanical strength of a fiber reinforced composite foam may not fully be improved. A more preferable content is 30 to 60% by mass.
The method for impregnating the resin in the fiber reinforced resin material is not particularly limited, for example,
(1) A method of immersing a fiber base material in a synthetic resin and impregnating the fiber base material with a synthetic resin (2) A method of applying a synthetic resin to the fiber base material and impregnating the fiber base material with a synthetic resin It is done.

(A-3) Properties The thickness of the fiber reinforced resin material is preferably 0.02 to 2 mm. The fiber reinforced resin material having a thickness within this range is excellent in mechanical strength despite being lightweight. A more preferable thickness is 0.05 to 1 mm.
The basis weight of the fiber reinforced resin material is preferably 50 to 4000 g / m ² . When the basis weight is within this range, the fiber-reinforced resin material can be made light and excellent in strength. A more preferable basis weight is 100 to 1000 g / m ² .
The trade name “NNGF60-03s” of Nagase Chemtech Co., Ltd. can also be used as the fiber reinforced resin material.

(B) Resin Foam The resin foam is a fusion product of the above foamed particles.
It is preferable that the resin foam has a density of 0.015 to 0.5 g / cm ³ . If the density is too low, the mechanical properties may deteriorate. If the density is too high, the lightness may be impaired or it may become brittle. The density is more preferably 0.02 to 0.4 g / cm ³ .

(C) Configuration The configuration of the fiber-reinforced composite foam is not particularly limited as long as the fiber-reinforced resin material and the resin foam are fused and integrated together. As a configuration, for example,
(1) Configuration in which the fiber reinforced resin material is positioned so as to cover the entire surface and a part of the surface of the resin foam (2) Configuration in which the fiber reinforced resin material is dispersed in a granular or layered manner inside the resin foam (3) The structure etc. which combined the said structure (1) and (2) are mentioned.

In the configuration (1), the fiber-reinforced composite foam is preferably covered with a fiber-reinforced resin material at a surface of 50% or more. When the coating is less than 50%, the effect of improving the mechanical strength of the fiber-reinforced composite foam may not be sufficient. More preferably, 60% or more of the surface is coated, and more preferably 80% or more of the surface is coated.
Moreover, when the fiber reinforced composite foam has a polyhedral structure, the fiber reinforced resin material preferably covers the surface having the largest area.

In the configuration (2), the ratio of the fiber reinforced resin material contained in the fiber reinforced composite foam to the entire fiber reinforced composite foam is preferably 10 to 60% by volume. When the ratio is less than 10% by volume, the effect of improving the mechanical strength of the fiber-reinforced composite foam may not be sufficient. When it is more than 60% by volume, the lightweight property of the fiber-reinforced composite foam may be impaired. A more desirable ratio is 20 to 50% by volume, and a still more desirable ratio is 25 to 45% by volume.
It is preferable that at least the configuration (1) is provided among the above configurations.

(B) Manufacturing method A manufacturing method is demonstrated below by making into an example the case where a fiber reinforced composite foam is prismatic shape and is provided with the said structure (1). Specifically, the surface of the prismatic resin foam is covered with a sheet-like fiber reinforced resin material by heat fusion.
The fiber reinforced composite foam can be manufactured, for example, according to the procedure shown in FIGS. FIG. 5A shows the expanded particle filling step, FIG. 5B shows the pressing and heating step, FIG. 5C shows the fusion step, and FIG. 5D shows the mold release step.
First, the fiber reinforced resin material 72, the foamed particles 73, and the fiber reinforced resin material 73 are arranged in this order on the mold 71 (FIG. 5A). Here, if it arrange | positions in order of a foam particle, a fiber reinforced resin material, and a foam particle in a shaping | molding die, the fiber reinforced composite foam in which the fiber reinforced resin material was included can be obtained. In addition, when using a granular fiber reinforced resin material, if the foam particles and the granular fiber reinforced resin material are mixed and placed in a mold, a fiber reinforced composite foam in which the granular fiber reinforced resin material is dispersed can be obtained. Can be obtained.

Next, the fiber reinforced resin material 72, the foamed particles 73, and the fiber reinforced resin material 74 are sealed with a pair of molding dies 71 and 75, and then heated while being pressed (FIG. 5B).
As a heating device used in the fiber reinforced resin material heating step and the resin foam heating step, for example, an infrared heater, a carbon heater, a hot air dryer, a heating plate, a band heater, a cartridge heater and the like can be used.
The pressing pressure is preferably determined with reference to the compressive stress below the glass transition point of the main resin of the expanded particles.
If the glass transition point is too high, the fiber reinforced resin material may be rapidly cooled to lower the surface property. If it is too low, it takes time to cool the fiber reinforced resin material, and the production cycle may be lowered. Therefore, it is preferable that it is 40-180 degreeC, and 50-150 degreeC is more preferable.

If the pressure at the time of press molding is too low, the integrity between the fiber-reinforced resin material and the resin foam may be lowered. If it is too high, the resin foam may be compressed, making it difficult to obtain a desired molded product.
Therefore, it is preferable that the press molding pressure is within a predetermined range with respect to the foaming force (A). Specifically, it is preferably within the range of 0.1 MPa to (A + 40 MPa), and particularly preferably within the range of 0.2 MPa to (A + 20 MPa).

Next, the foamed particles 73 are foamed together by maintaining the heating to foam the foamed particles 73. As a result of the re-foaming, a fiber reinforced composite foam 77 made of a resin foam 76 made of a fused product of foamed particles and a fiber reinforced resin material covering it is obtained in the space defined by the molds 71 and 75. (FIG. 5C).
After the mold is cooled to a certain temperature, the fiber-reinforced composite foam 77 is taken out (FIG. 5 (d)). If the take-out temperature is too high, further foaming or shrinkage may occur after taking out, and it may be difficult to give a predetermined shape.
Therefore, when the glass transition point of the foam molded body in the fiber reinforced composite foam is Tgx (° C.), the fiber reinforced composite foam is cooled so that the mold temperature is (Tgx + 10 ° C.) or less. Is preferred.

That is, it is preferable to take out the fiber-reinforced composite foam after heat sealing from the mold in a state where at least the surface is cooled to a temperature of (Tgx + 10 ° C.) or less.
The surface temperature at the time of taking out the fiber reinforced composite foam from the molding die was measured by applying a measurement probe of a contact thermometer to the surface of the fiber reinforced composite foam immediately after taking out, at a plurality of locations (for example, about 10 locations). Is the average value of the measured values.
Further, in the present invention, the thermal fusion between the resin foam and the fiber reinforced resin material can be performed in a state where the center of the resin foam is at a lower temperature than the surface.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
<Glass transition point and melting point>
About a glass transition point and melting | fusing point (exothermic peak temperature), the value measured by the method described in JISK7121: 1987 "Plastic transition temperature measuring method" is intended.
However, the sampling method and temperature conditions are as follows.
Using a differential scanning calorimeter device, approximately 6 mg of the sample is filled so that there is no gap in the bottom of the aluminum measurement container. Under a nitrogen gas flow rate of 20 mL / min, the sample is cooled from 30 ° C. to −40 ° C. and then held for 10 minutes. Thereafter, the sample was heated from -40 ° C. to 290 ° C. (1st Heating), held at 290 ° C. for 10 minutes, and then cooled from 290 ° C. to −40 ° C. (Cooling), held for 10 minutes. Then, the temperature is raised from −40 ° C. to 290 ° C. (2nd Heating) to obtain a DSC curve.
In addition, all the temperature increase rates and temperature decrease rates are performed at 10 ° C./min, and alumina is used as a reference material.
The inflection point of the obtained curve is defined as the glass transition point, and the temperature at the top of the exothermic peak is defined as the exothermic peak temperature (melting point).
The differential scanning calorimeter uses a product name “DSC6220 type” manufactured by SII Nano Technology.

<Heating expansion start temperature (foaming start temperature)>
The diameter of the expanded particles at 25 ° C. is measured and set as the initial diameter. Next, a constant temperature bath is set every 5 ° C., and the lowest temperature at which the size of the expanded particles expands is defined as the heating expansion start temperature. It is determined that the thermal expansion has started when the initial diameter is 0.5 mm or more larger than the initial diameter.

<Bulk density (apparent density)>
The bulk density is a value measured according to JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. That is, it measures using the apparent density measuring device based on JISK6911, and calculates the bulk density of a thermoplastic resin expanded particle based on a following formula.
Bulk density of thermoplastic resin expanded particles (g / cm ³ )
= [Mass of measuring cylinder with sample (g) -Mass of measuring cylinder (g)] / [Capacity of measuring cylinder (cm ³ )]

<Foamed particle size>
The average particle diameter of the expanded particles is calculated as follows. First, 20 expanded particles are extracted, the expanded expanded particles are magnified 10 times using an optical microscope, and an enlarged photograph is taken. The diameter of the perfect circle having the smallest diameter that can surround the expanded particles in the enlarged photograph is taken as the particle size of each expanded particle. The arithmetic average value of the particle diameters (diameters) of the 20 expanded particles is defined as the expanded particle diameter of the expanded particles. As the optical microscope, an optical microscope marketed under the trade name “Digital Microscope VHX-1000” manufactured by Keyence Corporation is used.

<Skin thickness>
The expanded particles are sliced with a thickness of 0.2 to 0.3 mm. Next, an arbitrary particle is photographed at 200 times with a scanning electron microscope, and the distance from the particle surface to the center is measured to a non-foamed (non-foamed region) or a region having a bubble diameter of 50 μm or less. . This measurement is performed at 10 locations in the arbitrary direction of the expanded particle cross section, and the average value of the 10 values obtained is taken as the skin thickness. The determination of the bubble diameter of 50 μm or less is performed for the shortest distance of a straight line connecting arbitrary points on the outer peripheral edge of each bubble (inside the bubble film).

<Crystallinity>
The crystallinity of the surface layer and the inner layer of the resin foam is measured by the method described in JIS K7122: 1987 “Method for measuring the transition heat of plastic”.
In order to obtain the crystallinity, about 6 mg of a rectangular parallelepiped sample cut out from the layer to be measured is collected, and thermal analysis is performed on this sample.
In addition, when a sample is cut out from the inner layer of the resin foam, in principle, the sample is cut out so as to include the center of gravity of the resin foam.
Specifically, the crystallinity can be determined as follows.
Using a differential scanning calorimeter (trade name “DSC6220 type” manufactured by SII Nano Technology Co., Ltd.), the sample was filled in the bottom of an aluminum measurement container so that there was no gap, and the sample was supplied with a nitrogen gas flow rate of 30 mL / min. And kept at 30 ° C. for 2 minutes.
Thereafter, a DSC curve is obtained when the sample is heated from 30 ° C. to 290 ° C. at a rate of 10 ° C./min.
At that time, alumina is used as the reference material.

The crystallinity of the surface layer and the inner layer of the resin foam is the difference between the heat of fusion (mJ / mg) determined from the area of the melting peak and the heat of crystallization (mJ / mg) determined from the area of the crystallization peak. It is obtained gradually by the theoretical heat of fusion ΔH ₀ of the complete crystal of the thermoplastic resin.
For example, ΔH ₀ of polyethylene terephthalate is 140.1 mJ / mg, and ΔH ₀ of polylactic acid is 93.0 mJ / mg.
The crystallinity of the layer to be measured for the resin foam is calculated based on the following formula.
Crystallinity of the layer to be measured for resin foam (%)
= 100 × (| heat of fusion (mJ / mg) | − | heat of crystallization (mJ / mg) |) / ΔH ₀ (mJ / mg)
Separately, prepare five resin foams, measure the crystallinity of the surface layer and the inner layer of each resin foam in the same manner as described above, and crystallize the respective surface layers of the five resin foams. The arithmetic average value of the degree is the crystallinity of the surface layer of the resin foam, and the arithmetic average value of the crystallinity of the inner layer of each of the five resin foams is the crystallinity of the inner layer of the resin foam. .

<Foaming agent remaining amount (residual gas amount)>
The amount of residual blowing agent in the expanded particles is measured using a gas chromatograph.
Specifically, the amount of residual blowing agent is measured as follows when the blowing agent is a hydrocarbon such as butane.
Weigh out 10 to 20 mg of expanded particles, set at the cracking furnace inlet of Pyrolysis Furnace PYR-1A (manufactured by Shimadzu Corporation), purge with carrier gas (helium gas) for about 15 seconds, and mix the mixed gas at the time of sample setting Discharge.
After that, the sample is inserted into the core and heated to release the gas. This released gas is measured using a gas chromatograph manufactured by Shimadzu Corporation, and each standard gas calibration curve is used from the peak area of the obtained chromatograph. Then, the remaining foaming agent in the sample is quantified.

[Gas chromatograph conditions]
Measuring device: Gas chromatograph GC-14B (manufactured by Shimadzu Corporation)
Column: Polapack Q (80/100) 3 mmφ × 1.5 m (manufactured by GL Sciences Inc.)
Data processing device: C-R3A
Detector: TCD
Column temperature: 100 ° C
Inlet temperature: 120 ° C
Detector temperature: 120 ° C
Carrier gas: Helium carrier gas flow rate: 1 mL / min
[Heating furnace conditions]
Measuring device: Pyrolysis furnace PYR-1A (manufactured by Shimadzu Corporation)
Heating furnace temperature: 240 ° C
[Calculation conditions]
Calibration curve standard gas: i-butane, n-pentane calculation method: An analytical curve of i-butane and n-pentane was prepared in advance by the absolute calibration curve method, and the residual foaming agent amount of the obtained sample was determined for each standard gas. Calculate with a calibration curve. In the results, the n-butane gas amount is the i-butane conversion amount, and the i-pentane gas amount is the n-pentane conversion amount.

<Open cell ratio>
The open cell ratio is measured in the following manner based on the measurement method described in ASTM D-2856.
First, the apparent volume of the resin foam particles is measured to obtain an apparent volume V ₁ (cm ³ ). Next, the actual sample volume V ₂ (cm ³ ) of the resin foam particles is measured by a 1-1 / 2-1 atmospheric pressure method using a volumetric air comparison type hydrometer.
As the volumetric air comparison type hydrometer, a commercially available product under the trade name “1000 type” manufactured by Tokyo Science Co., Ltd. is used.

<Maximum heating rate>
The initial diameter of the expanded particles at 25 ° C. is measured, and the expanded particles are placed in each thermostat and heated. The maximum expansion coefficient of heating is calculated by observing the expanded particles until they expand to the maximum, and dividing the diameter by the initial diameter and multiplying by 100. In addition, when it is difficult to measure the maximum value, foam particles are placed on an inorganic powder such as talc, and the talc depression is defined as the maximum expansion diameter.

<Heating expansion rate (volume increase rate)>
The volume increase rate (volume% / min) of the resin foam is obtained by heating 100 foamed particles at a certain temperature for a certain time, and dividing the volume change before and after the heating by the heating time.
Specifically, the heating time of the test piece is set to 2 minutes, and a constant temperature dryer having a trade name “DN44” of Yamato Scientific Co., Ltd. is used as a heating device.

<Foaming force at the compounding temperature (maximum expansion pressure)>
The foaming power of the resin foam is measured continuously by using a universal testing machine used in "Foamed plastics-compression test of hard material", and the load generated when the resin foam expands (foams) by heating. It is determined as a value obtained by dividing the maximum load detected in a predetermined time after the start of measurement by the test piece area (area in the initial state).
Specifically, the foaming force is obtained as follows.
The foamed particles are filled in a cube-shaped mold (one surface is open) covered with five surfaces each having an inner dimension of 40 mm and preheated to a compounding temperature (press temperature in the case of a press). One surface of the mold is in an open state and is an open surface.
The measurement is performed using a universal testing machine, Tensilon-equipped high and low temperature thermostat and universal testing machine data processing software.
A load generated by expansion (foaming) from a mold sandwiched between an upper compression plate and a lower compression plate in a thermostatic chamber is measured. At the beginning of the test, the open surface is in contact with the upper compression plate.
The universal testing machine uses, for example, the product name “UCT-10T” of Orientec.
Tensilon-related high and low temperature thermostat is T.T. S. E. Use a commercially available product.
As the universal testing machine data processing software, a commercial product of UTPS-STD Software Brain is used.
The foaming force (expansion pressure) is determined below from the maximum load generated with expansion of the foamed particles upon heating.
Foaming force (mN / mm ³ ) = maximum load F (mN) / mold opening surface area (mm)

<Density of core material (resin foam) after molding>
The density refers to a value measured according to JIS K7222 “Foamed plastics and rubbers—Measurement of apparent density”.

<Density variation>
Test specimens are taken from any 10 locations in the resin foam within the fiber reinforced composite foam.
The collected test piece mass is measured, and then the test piece is placed in a graduated cylinder filled with water, and the volume is measured.
Then, the arithmetic mean value of the density of each test piece is defined as “average core material density”, and the density variation is evaluated based on the number of test pieces whose density differs by 20% or more from the “average core material density”.
○: Less than two.
Δ: Two or more and less than five.
X ... 6 or more.

<Lightening effect>
Since the fiber reinforced composite foam compresses the resin foam by molding, the weight reduction effect of the fiber reinforced composite foam is evaluated based on the following criteria.
Weight reduction effect (%) = 100 × (volume after molding of fiber reinforced composite foam / bulk volume of initial expanded particles)
○: 80% or more.
Δ: 50% or more and less than 80%.
X: Less than 50%.

<Surface appearance>
In the fiber reinforced composite foam, the total surface area (S0) of the fiber reinforced resin material and the total area (S1) of the portion where the fiber is exposed on the surface thereof are calculated. Is calculated.
Judgment is made according to the following criteria based on the degree of exposure of the fibers.
In addition, it is set as "x" when a fiber reinforced composite foam is not obtained.
Fiber exposure (%) = 100 × S1 / S0
○: The degree of fiber exposure is less than 10%.
Δ: Fiber exposure is 10% or more and less than 20%.
X: Fiber exposure is 20% or more.

Example 1
First, foamed particles were produced using the production apparatus shown in FIGS.
That is, 100 parts by mass of 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin (manufactured by Eastman Co., Ltd., trade name “EN099”, melting point: 238.5 ° C.), master batch (polyethylene) containing polyethylene terephthalate resin and talc. (Terephthalate resin content: 60% by mass, talc content: 40% by mass) A resin composition containing 1.8 parts by mass and pyromellitic anhydride 0.26 parts by mass has an aperture of 65 mm and an L / D ratio of 35 It supplied to the single screw extruder and melt-kneaded at 290 degreeC.
Subsequently, mixed butane composed of 35% by mass of isobutane and 65% by mass of normal butane was added from the middle of the extruder to 1.6 parts by mass with respect to 100 parts by mass of the total amount of 1,4-cyclohexanedimethanol-modified polyethylene terephthalate resin and polyethylene terephthalate resin. It was press-fitted into the molten resin composition so as to be part by mass, and was uniformly dispersed in the resin composition.

Then, after the molten resin composition was cooled to 280 ° C. at the front end of the extruder, the resin composition was extruded and foamed from each nozzle of the multi-nozzle mold 1 attached to the front end of the extruder.
The multi-nozzle mold 1 had 20 nozzles having a diameter of the outlet portion 11 of 1 mm. The virtual circle A had a diameter of 139.5 mm. The two rotary blades 5 were integrally provided with a phase difference of 180 ° in the circumferential direction of the rotary shaft 2. The cooling drum 41 had an inner diameter of 320 mm and a volume of 17684 cm ³ . The cooling water 42 was 20 degreeC.
Then, the rotary blade 5 disposed on the front end face 10 of the multi-nozzle mold 1 is rotated at a rotational speed of 2500 rpm, and the extruded foam is cut by the rotary blade 5 from the outlet portion 11 of each nozzle of the multi-nozzle mold 1. Thus, substantially spherical expanded particles were produced.

At this time, the extruded foam was composed of an unfoamed portion that maintained the state immediately after being extruded from the nozzle of the multi-nozzle mold 1 and a foaming portion that was in the process of foaming and continued to the unfoamed portion. The extruded foam was cut at the open end of the outlet portion 11 of the nozzle, and the cut of the extruded foam was an unfoamed portion.
In producing foamed particles, first, the rotating shaft 2 was not attached to the multi-nozzle mold 1 and the cooling member 4 was retracted from the multi-nozzle mold 1.
The extruded foam was blown outward or forward by the cutting stress of the rotary blade 5. Next, with respect to the cooling water 42 flowing along the inner surface of the cooling drum 41 of the cooling member 4, the surface of the cooling water 42 so as to follow the cooling water 42 from the upstream side to the downstream side of the flow of the cooling water 42. Were made to collide with each other from the oblique direction, entered into the cooling water 42 and immediately cooled.

The cooled foamed particles were discharged together with the cooling water 42 through the discharge port 41e of the cooling drum 41, and then separated from the cooling water 42 by a dehydrator. Thereafter, the expanded particles were stored at 25 ° C. for 20 hours.
The expanded particles had a bulk density of 0.14 g / cm ³ . Moreover, as shown in Table 1, the expanded particles had expandability.
Next, a reinforced fiber resin material formed from a woven fabric made of carbon fiber (a face material in which a twill woven fabric made of carbon fiber is impregnated with a resin; trade name “Pyrofil Prepreg TR3523-395GMP” manufactured by Mitsubishi Rayon Co., Ltd., basis weight: 200 g / m ² , thickness: 0.23 mm) were prepared.
The fiber component constituting the fiber reinforced resin material has a thickness of 0.5 mm, which is overlapped in advance so that the length direction of the warp is sequentially 0 ° and 90 °.

After the foam particles are put into a mold having a mold temperature of 140 ° C. so as to be a laminate of fiber reinforced resin material / resin foam / fiber reinforced resin material, the foam particles are held for 30 seconds, and then the mold temperature is 140 ° C. The mold was pressed at 0.8 MPa.
The foamed particles are foamed by heat conduction between the mold and the fiber reinforced resin material and increase in volume, and are softened by heat conduction from the mold and the fiber reinforced resin material, so that the resin foam density is 0.16 g / The fiber reinforced composite foam was compressed at a mold temperature of 130 ° C. for 5 minutes so as to be cm ³ . The mold was cooled until the mold temperature reached 60 ° C. below the glass transition point of the modified polyethylene terephthalate resin, and the fiber-reinforced composite foam was taken out.

(Examples 2, 3, 5-10 and 12-15, Comparative Examples 1 and 2)
In the above Examples and Comparative Examples, fiber reinforced composite foams were obtained in the same manner as in Example 1 except for the conditions in Tables 1 and 2. In Example 3, as a fiber reinforced resin material, a reinforced fiber resin material formed from a woven fabric made of carbon fiber (manufactured by BOND LAMINATES, trade name “TEPEX dynamic 108”, reinforcing synthetic resin: thermoplastic polyurethane (TPU) ), Basis weight: 400 g / m ² , thickness: 0.5 mm). The fiber reinforced resin material contained 45% by mass of TPU resin as a thermoplastic resin. The reinforcing fiber base material constituting the fiber reinforced resin material was preliminarily laminated to have a thickness of 0.5 mm so that the longitudinal direction of the warp was 0 ° and 90 °.

(Examples 4 and 11)
The resin composition was converted into a styrene-methyl methacrylate-maleic anhydride copolymer (styrene unit: 45.9% by mass, methyl methacrylate unit: 21.5% by mass, maleic anhydride unit: 32 as an acrylic copolymer. .6 mass%, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Regisphi R200”, 100 parts by mass of glass transition point Tg: 137.9 ° C., styrene-methyl methacrylate-maleic anhydride copolymer (styrene unit: 45.%). 9% by mass, methyl methacrylate unit: 21.5% by mass, maleic anhydride unit: 32.6% by mass, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Regisphi R200”, glass transition point Tg: 137.9 ° C.) A master batch containing styrene (methyl methacrylate-maleic anhydride copolymer content: 60 mass%, talc content: 40 mass%) %) A fiber-reinforced composite foam was produced in the same manner as in Example 1 except that the conditions shown in Tables 1 and 2 were used instead of the resin composition containing 1.8 parts by mass.
In the table, the styrene-methyl methacrylate-maleic anhydride copolymer is referred to as “acrylic copolymer”.

From Tables 1 and 2, the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. 5% by volume / min or more (heated at each temperature for a predetermined time, and the volume change before and after heating is divided by the predetermined measurement time to obtain per unit time). It can be seen that there is no variation in density, light weight, and good appearance.

DESCRIPTION OF SYMBOLS 1 Nozzle metal mold, 2 Rotating shaft, 3 Drive member, 4 Cooling member, 5 Rotary blade, 10 Front end surface, 11 Outlet part, 41 Cooling drum, 41a Front part, 41b Perimeter wall part, 41c Supply port, 41d Supply pipe, 41e Discharge port, 41f Discharge pipe, 42 Coolant (water), A Virtual circle, 1a, 1b, 1c, 1d Warp, 71, 75 Mold, 72, 74 Fiber reinforced resin material, 73 Foamed particles, 76 Resin foam, 77 Fiber-reinforced composite foam

Claims (5)

A fiber reinforced resin material is placed in a mold, and thermoplastic resin foam particles having a bulk density of 0.015 to 0.6 g / cm ³ are filled into the mold before, after or simultaneously with the placement, and then the thermoplastic It is a method for producing a fiber reinforced composite foam by foaming resin foam particles to obtain a fiber reinforced composite foam by laminating and integrating the fiber reinforced resin material and the resin foam.
The foamed thermoplastic resin particles have the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. Is a fiber-reinforced composite having a foaming property of 5 vol% / min or more (heating at each temperature for a predetermined time and dividing the volume change before and after heating by a predetermined measurement time to obtain per unit time) A method for producing a foam. A thermoplastic resin foam particle used in the method for producing a fiber-reinforced composite foam according to claim 1,
The foamed thermoplastic resin particles have the following properties (1) and (2):
(1) The maximum heating expansion rate in the heating temperature range from room temperature to the melting point is 30 to 300%. (2) The heating expansion rate at any point in the temperature range from the heating expansion start temperature to the maximum heating expansion rate. Is a fiber-reinforced composite having a foaming property of 5 vol% / min or more (heating at each temperature for a predetermined time and dividing the volume change before and after heating by a predetermined measurement time to obtain per unit time) Thermoplastic resin foam particles for forming foam.   The thermoplastic resin expanded particles for forming a fiber-reinforced composite foam according to claim 2, wherein the heating expansion start temperature is 50 ° C. or higher.   The thermoplastic resin foam particles for forming a fiber-reinforced composite foam according to claim 2 or 3, wherein the thermoplastic resin foam particles contain 0.1 to 5.0 mass% of a foaming agent.   The thermoplastic resin for producing a fiber-reinforced composite foam according to any one of claims 2 to 4, wherein the fiber-reinforced composite foam is a member for constituting a moving body, an electronic device casing, a wind turbine blade, or a member for an automobile. Resin foam particles.

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