JP2015105369A - Two-layer structure olefin based resin pellet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-layer structure olefin based resin pellet in which polyhydric alcohol is stably held.SOLUTION: The two-layer structure olefin based resin pellet uses as a core material layer, an olefin based resin composition including a poly olefine based resin, a copolymer of ethylene and carboxylate, and polyhydric alcohol. The olefine based resin composition including the poly olefine resin is laminated as a sheath layer on the outer peripheral surface of the core material layer.

Description

  The present invention relates to a two-layer structure olefin resin pellet having a core layer and a sheath layer, in which a polyhydric alcohol is stably held, and a method for producing the same.

  Extrudates such as fibers and sheets formed using a polyolefin-based resin such as polyethylene are used in various applications. For example, the fiber and the sheet can be used as a fiber and a sheet having effects such as insect repellent by containing a trace amount of a drug such as a liquid insect repellent. In addition, when imparting antistatic performance to a film formed using a polyolefin resin, a small amount of liquid polyhydric alcohol can be added to migrate to the molding surface to prevent charging. Alternatively, the transition time of the polyhydric alcohol to the surface of the molded product can be adjusted by adding it in combination with a small amount of polyhydric alcohol and another antistatic material such as a fatty acid ester.

  Extrusion moldings, such as the said fiber, a sheet | seat, and a film, are manufactured by fuse | melting and knead | mixing the resin composition containing polyolefin resin, for example, and shape | molding in a desired shape.

  Such a resin composition may be used by directly melting and kneading a plurality of raw materials according to the composition of the extruded product as it is. In many cases, it is separately manufactured in a pellet form and blended with a resin as a main component so as to have a desired concentration.

  As said high concentration masterbatch pellet, there exists a pellet of patent document 1, for example. Patent Document 1 discloses an olefin-based resin composition (A) containing an insect-repellent compound, a granular inorganic filler, a metal soap, and an olefin-based resin (a) having a relatively high solubility in the insect-repellent compound. An olefin resin composition (B) mainly composed of an olefin resin (b) having a relatively low solubility with respect to the insect repellent compound is laminated as a sheath layer on the outer peripheral surface of the core material layer. A two-layer olefin resin pellet for an insect repellent resin composition is described. According to the pellets described in Patent Document 1, since the sheath layer serves as a cover, when transporting and storing pellets with high drug concentration, they are exposed to high temperatures depending on the climate and location, and when transporting and storing are prolonged. Even so, bleeding of the insect repellent compound on the pellet surface can be prevented.

Japanese Patent Laying-Open No. 2005-139329 (released on June 2, 2005)

  The pellet described in Patent Document 1 contains a porous inorganic filler. The inorganic filler can carry a liquid insect repellent. However, when the inorganic filler is contained in the pellet, various problems may occur in the process of producing an extruded product using the pellet. Specifically, when producing an extruded film using pellets as the above problem, there are cases where the film is not uniformly stretched due to a decrease in stretchability due to the inorganic filler. Moreover, when manufacturing a sheet | seat, a profile extrudate, etc. using a pellet, an unevenness | corrugation generate | occur | produces on the surface with an inorganic filler (for example, fish eye), and the touch of a product falls or the external appearance as a product is impaired. There was a case.

  Then, although it was examined to set it as the formulation which does not add an inorganic filler, there existed a problem that it was difficult to hold | maintain a polyhydric alcohol stably in a pellet. Specifically, when a high-concentration polyhydric alcohol is blended in the resin to produce pellets, the polyhydric alcohol bleeds on the pellet surface in a short time. Since the polyhydric alcohol is a viscous liquid, stickiness occurs on the pellet surface, and the pellets may adhere to each other and handleability may be extremely deteriorated. In addition, when the strand cutting method is used also when producing pellets, the strength of the molten resin is lowered and easily broken, so that it was difficult to produce the pellets by a stable continuous operation.

  In the prior art including the technique described in Patent Document 1, no technique for stably holding polyhydric alcohol in the pellet has been proposed.

  This invention is made | formed in view of said problem, The objective is to provide the two-layer structure olefin resin pellet in which the polyhydric alcohol is hold | maintained stably.

  As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that as a polyolefin resin composition for forming the core layer, a copolymer of ethylene and a carboxylic acid ester is added to the polyolefin resin (a). It was uniquely found that the polyhydric alcohol can be stably held in the pellet by including the polymer. The present invention has been completed based on new findings uniquely found by the present inventors, and includes the following inventions.

  That is, in order to solve the above-mentioned problems, the two-layer olefin resin pellet according to the present invention uses the olefin resin composition (A) as a core material layer, and an olefin resin composition on the outer peripheral surface of the core material layer. The product (B) is a two-layer olefin resin pellet formed by laminating as a sheath layer, and the olefin resin composition (A) comprises a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester. The olefin resin composition (B) contains a coalescence and a polyhydric alcohol, and is characterized by containing a polyolefin resin (b).

  According to the above configuration, the polyolefin resin composition (A) forming the core material layer contains the polyolefin resin (a) and a copolymer of ethylene and a carboxylic acid ester, so Alcohol can be held stably.

  Specifically, the carboxylic acid ester (carboxylic acid ester monomer unit) contained in the polyolefin-based resin composition (A) contains a large amount of carboxylic acid ester (carboxylic acid ester monomer unit) depending on the abundance ratio in the polyolefin-based resin composition (A). The solubility of the monohydric alcohol is adjusted. As a result, the carboxylic acid ester plays a role in controlling the bleed amount of the polyhydric alcohol on the surface of the olefin resin pellet.

  Furthermore, according to the said structure, since the sheath layer is laminated | stacked on the outer peripheral surface of the core material layer, while the stickiness of the core material layer resulting from a polyhydric alcohol can be suppressed, the said pellet can be reinforced. .

  Therefore, the two-layer structure olefin resin pellet in which the polyhydric alcohol is stably held can be provided.

  In the two-layer olefin resin pellet according to the present invention, the content of the polyolefin resin (a) with respect to the total amount of the olefin resin composition (A) is 0.1% by mass or more and 55% by mass or less. preferable.

  According to the said structure, since content of polyolefin resin (a) in a core material layer is prescribed | regulated to the preferable range, the two-layer structure olefin resin pellet by which polyhydric alcohol is hold | maintained more stably is provided. can do.

  In the two-layer structure olefin resin pellet according to the present invention, the content of the copolymer of ethylene and carboxylic acid ester is 40% by mass or more and 99% by mass or less with respect to the total amount of the olefin resin composition (A). It is preferable.

  According to the said structure, since content of the copolymer of ethylene and carboxylic acid ester in a core material layer is prescribed | regulated to the preferable range, a polyhydric alcohol can be more stably hold | maintained in a core material. .

  In the two-layer structure olefin resin pellet according to the present invention, the content of the polyhydric alcohol with respect to the total amount of the olefin resin composition (A) is preferably 0.1% by mass or more and 10% by mass or less.

  According to the said structure, since content of the polyhydric alcohol in a core material layer is prescribed | regulated to the preferable range, a polyhydric alcohol can be more stably hold | maintained in a core material.

  In the two-layer olefin resin pellet according to the present invention, the mass ratio of the olefin resin composition (A) to the olefin resin composition (B) is preferably 10: 1.

  According to the said structure, since the mass ratio of the olefin resin composition (A) which forms a core material layer and the olefin resin composition (B) which forms a sheath layer is prescribed | regulated to the preferable value, it is more stable. In particular, a polyhydric alcohol can be held in the core material layer, and a two-layer structure olefin resin pellet having suitable strength can be provided.

  In the two-layer structure olefin resin pellet according to the present invention, the copolymer of ethylene and carboxylic acid ester is preferably an ethylene-methyl methacrylate copolymer.

  According to the said structure, a polyhydric alcohol can be hold | maintained in a core material more stably.

  In the two-layer olefin resin pellet according to the present invention, the polyhydric alcohol is preferably glycerin or ethylene glycol.

  According to the said structure, a polyhydric alcohol can be hold | maintained in a core material more stably.

  In order to solve the above problems, the method for producing a two-layer olefin resin pellet according to the present invention uses the olefin resin composition (A) as a core material layer, and an olefin resin on the outer peripheral surface of the core material layer. A method for producing a two-layer olefin resin pellet comprising a step of laminating a composition (B) as a sheath layer, wherein the olefin resin composition (A) comprises a polyolefin resin (a), ethylene, It contains a copolymer with a carboxylic acid ester and a polyhydric alcohol, and the olefin resin composition (B) is characterized by containing a polyolefin resin (b).

  According to the above configuration, the polyolefin resin composition (A) forming the core material layer contains the polyolefin resin (a) and a copolymer of ethylene and a carboxylic acid ester, so Alcohol can be held stably.

  Furthermore, according to the said structure, since the sheath layer is laminated | stacked on the outer peripheral surface of the core material layer, while the stickiness of the core material layer resulting from a polyhydric alcohol can be suppressed, the said pellet can be reinforced. .

  Therefore, the two-layer structure olefin resin pellet in which the polyhydric alcohol is stably held can be produced by stable continuous operation.

  A two-layer olefin resin pellet according to the present invention is a two-layer olefin resin pellet comprising a core material layer and a sheath layer laminated on the outer peripheral surface of the core material layer, the core The olefin resin composition (A) that forms the material layer includes three components: a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and a polyhydric alcohol.

  Therefore, there is an effect that it is possible to provide a two-layer structure olefin resin pellet in which polyhydric alcohol is stably held.

  Moreover, when manufacturing the two-layer structure olefin resin pellet which concerns on this invention, the effect that the two-layer structure olefin resin pellet in which the polyhydric alcohol is stably hold | maintained can be manufactured by the stable continuous operation. Play.

It is a perspective view which shows the two-layer structure olefin resin pellet which concerns on this invention.

  Hereinafter, although an example of an embodiment of the invention is explained in detail, the present invention is not limited to these.

  As shown in FIG. 1, the two-layer structure olefin-based resin pellet according to the present invention includes a core material layer 1 and a sheath layer 2 laminated on the outer peripheral surface of the core material layer. For example, fibers and sheets can be produced by melting and stretching the two-layer structure olefin resin pellets. When manufacturing the said fiber, a sheet | seat, etc., you may use only the said 2 layer structure olefin resin pellet, and mix and use the said 2 layer structure olefin resin pellet and another resin composition etc. Also good.

[1. (Core material layer)
In the two-layer olefin resin pellet according to the present invention, the olefin resin composition (A) is used as a core material layer, and the olefin resin composition (A) is a polyolefin resin (a), ethylene and a carboxylic acid ester. And a copolymer, and a polyhydric alcohol.

<Polyolefin resin (a)>
The polyolefin resin (a) contained in the core material layer is not particularly limited. For example, ethylene wax, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene, high density Examples include polyethylene, ethylene-propylene copolymer (EPM), and ethylene-propylene-diene copolymer (EPDM). Among the above, density 0.941 g / cm ³ or less, especially a density 0.929 g / cm ³ or less of low density polyethylene, linear low density polyethylene, ethylene waxes are preferred. When high density polyethylene is used as the polyolefin resin (a), high density polyethylene having a density of 0.942 g / cm ³ or more may be used.

  The content of the polyolefin resin (a) with respect to the total amount of the olefin resin composition (A) is preferably 0.1% by mass or more and 55% by mass or less, and more preferably 0.1% by mass or more and 52% by mass. More preferably, it is more preferably 0.1% by mass or more and 18% by mass or less. According to the said structure, since content of polyolefin resin (a) in a core material layer is prescribed | regulated to the preferable range, the two-layer structure olefin resin pellet by which polyhydric alcohol is hold | maintained more stably is provided. can do. The polyolefin resin (a) contained in the olefin resin composition (A) may be one type or two or more types. When two or more types of polyolefin resin (a) are used, the ratio of the polyolefin resin (a) is arbitrary as long as the polyhydric alcohol can be stably held.

<Copolymer of ethylene and carboxylic acid ester>
In the two-layer structure olefin resin pellet according to the present invention, the olefin resin composition (A) forming the core material layer contains a copolymer of ethylene and a carboxylic acid ester together with the polyethylene resin (a). Therefore, the polyhydric alcohol can be stably held.

  Specifically, the carboxylic acid ester (carboxylic acid ester monomer unit) adjusts the solubility of the polyhydric alcohol according to the abundance ratio of the carboxylic acid ester in the polyolefin resin composition (A). As a result, the carboxylic acid ester plays a role in controlling the bleed amount of the polyhydric alcohol on the surface of the olefin resin pellet.

  However, as demonstrated in the examples below, even if a resin composition comprising two components of a copolymer of ethylene and a carboxylic acid ester and a polyhydric alcohol is used as a core material layer, It cannot be held stably. A polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and an olefin resin composition (A) containing three components of a polyhydric alcohol are used as a core material layer, and a sheath layer is further laminated 2 By using a pellet having a layer structure, the polyhydric alcohol can be stably retained. This was first discovered by the inventors.

  Examples of the copolymer of ethylene and carboxylic acid ester include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), and ethylene-methyl acrylate copolymer (EMA). ), Ethylene-ethyl acrylate copolymer (EEA). Among the above, an ethylene-methyl methacrylate copolymer is particularly preferable.

  The content of carboxylic acid ester in the copolymer of ethylene and carboxylic acid ester is not particularly limited, but is most preferably 1% by mass or more and 30% by mass or less when the copolymer is 100% by mass. .

  The content of the copolymer of ethylene and carboxylic acid ester with respect to the total amount of the olefin resin composition (A) is preferably 20% by mass or more and 99% by mass or less, and 40% by mass or more and 99% by mass. More preferably, it is 60 mass% or more and 99 mass% or less. According to the said structure, since content of the copolymer of ethylene and carboxylic acid ester in a core material layer is prescribed | regulated to the preferable range, a polyhydric alcohol can be more stably hold | maintained in a core material layer. .

  In addition, the copolymer of ethylene and carboxylic acid ester contained in the said olefin resin composition (A) may be one type, and may be two or more types. When two or more kinds of copolymers of ethylene and carboxylic acid ester are used, the ratio of the copolymer is arbitrary as long as the polyhydric alcohol can be stably held.

<Polyhydric alcohol>
The polyhydric alcohol is not particularly limited as long as it has two or more hydroxyl groups in one molecule. For example, dihydric alcohol (ethylene glycol, propylene glycol, etc.), trivalent alcohol ( Glycerin and the like). Among the above, in particular, when ethylene glycol or glycerin is used, it can be more stably held in the core material layer.

  Moreover, it is preferable that content of the polyhydric alcohol with respect to the whole quantity of the said olefin resin composition (A) is 0.1 to 10 mass%. According to the said structure, since content of the polyhydric alcohol in a core material layer is prescribed | regulated to the preferable range, a polyhydric alcohol can be hold | maintained more stably in a core material layer. Specifically, when the content of the polyhydric alcohol is 10% by mass or less, the polyolefin resin (a) and the copolymer of ethylene and carboxylic acid ester sufficiently function as a binder. The stickiness caused by alcohol and the decrease in the strength of the pellet can be further suppressed.

  The olefin-based resin composition (A) may not contain a filler other than the polyhydric alcohol, but for the purpose of containing a drug, the filler other than the polyhydric alcohol. May be included. Examples of the filler include organic fillers and inorganic fillers, and conventionally known fillers can be appropriately used. Examples of the organic filler include wood powder, and examples of the inorganic filler include silica and calcium carbonate.

  However, it is more preferable that the two-layer olefin resin pellet according to the present invention does not contain the inorganic filler. By not containing an inorganic filler, when producing a fiber or sheet by stretching the two-layer olefin resin pellet according to the present invention, it is possible to further suppress the occurrence of yarn breakage and unevenness on the surface. . In the present specification, “inorganic filler is not included” means that the content of the inorganic filler contained in the two-layer olefin resin pellet is below the detection limit by X-ray analysis. To do.

  In addition to the filler, various additives may be added to the olefin resin composition (A) as necessary. Examples of the additive include a colorant, an antioxidant, various stabilizers, an ultraviolet absorber, an antistatic agent, a flame retardant, a release agent, and a lubricant. Moreover, in order to give a specific function to the fiber and sheet etc. which were manufactured by extending | stretching the two-layer structure olefin resin pellet which concerns on this invention, an insecticide, a fungicide, Drugs such as bactericides, fragrances and deodorants may be contained. The content of the additive including the drug may be within a range in which the effects of various additives are obtained and the effect of stably holding the polyhydric alcohol is not impaired. For example, 0 mass% or more and 50 mass% or less of content of an additive may be sufficient with respect to the whole quantity of the said olefin resin composition (A).

[2. Sheath layer)
In the two-layer olefin resin pellet according to the present invention, a sheath layer is laminated on the outer peripheral surface of the core material layer. According to the said structure, since a core material layer is reinforced with a sheath layer, it can be set as the two-layer structure olefin resin pellet which has suitable intensity | strength. In addition, the polyhydric alcohol contained in the core material layer has viscosity, but since the sheath layer is laminated on the outer peripheral surface of the core material layer, the sheath layer serves as a cover, and the stickiness of the pellets Can be suppressed. Furthermore, when the core material layer contains a chemical such as an insect repellent, a fragrance, or a deodorant, bleeding of the chemical on the pellet surface can be prevented.

  The said sheath layer consists of an olefin resin composition (B). The olefin resin composition (B) contains a polyolefin resin (b). As the polyolefin resin (b), the same resin as the polyolefin resin (a) contained in the core material layer can be used. In addition, in the polyolefin resin (a) contained in the core material layer and the polyolefin resin (b) contained in the sheath layer, the same type of resin may be used, or another type of resin may be used. . From the viewpoint of facilitating the production of the two-layer olefin resin pellets, the polyolefin resin (a) and the polyolefin resin (b) are preferably of the same type, for example, the polyolefin resin (a) and the polyolefin resin. Both resins (b) are preferably linear low density polyethylene.

On the other hand, from the viewpoint of preventing bleeding of the polyhydric alcohol on the pellet surface, a polyolefin resin that is relatively highly soluble in the polyhydric alcohol is used as the polyolefin resin (a). As the resin (b), it is preferable to use a polyolefin-based resin having relatively low solubility with respect to the polyhydric alcohol. Specifically, from the viewpoint of preventing bleeding of polyhydric alcohol to the pellet surface, for example, as the polyolefin resin (a) Density 0.941 g / cm ³ or less, especially a density 0.929 g / cm ³ or less of It is preferable to use low-density polyethylene, linear low-density polyethylene, or ethylene wax, and use high-density polyethylene having a density of 0.942 g / cm ³ or more as the polyolefin resin (b).

  Moreover, it is preferable that mass ratio of the said olefin resin composition (A) and the said olefin resin composition (B) is 10: 1. According to the said structure, since the mass ratio of an olefin resin composition (A) and an olefin resin composition (B) is prescribed | regulated to the preferable value, a polyhydric alcohol is more stably hold | maintained in a core material. It is possible to provide a two-layer structure olefin-based resin pellet having a suitable strength.

  Similar to the olefin resin composition (A), various additives may be added to the olefin resin composition (B) as necessary. However, for the same reason as the olefin resin composition (A), the olefin resin composition (B) preferably contains no inorganic filler.

[Manufacturing method of two-layer structure olefin resin pellet]
The manufacturing method of the two-layer structure olefin resin pellet which concerns on this invention uses an olefin resin composition (A) as a core material layer, and uses the olefin resin composition (B) as a sheath layer in the outer peripheral surface of the said core material layer. A process for producing a two-layer olefin resin pellet comprising a step of laminating, wherein the olefin resin composition (A) comprises a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and Polyhydric alcohol is contained, The said olefin resin composition (B) is characterized by including the polyolefin resin (b).

  According to the above configuration, the polyolefin resin composition (A) forming the core material layer contains the polyolefin resin (a) and a copolymer of ethylene and a carboxylic acid ester, so Alcohol can be held stably. Furthermore, according to the said structure, since the sheath layer is laminated | stacked on the outer peripheral surface of the core material layer, while the stickiness of the core material layer resulting from a polyhydric alcohol can be suppressed, the said pellet can be reinforced. .

  Therefore, the two-layer structure olefin resin pellet in which the polyhydric alcohol is stably held can be produced. Moreover, according to the said structure, a two-layer structure olefin resin pellet can be manufactured by the stable continuous operation.

  The polyolefin resin (a), the polyolefin resin (b), the copolymer of ethylene and carboxylic acid ester, and the type and content of the polyhydric alcohol are as described above. The detailed explanation is omitted.

  The method for producing a two-layer olefin resin pellet according to the present invention can be realized by, for example, a conventionally known method such as coextrusion. For example, a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and a polyhydric alcohol are supplied from different supply ports to a twin screw extruder for the core. On the other hand, polyolefin resin (b) is supplied to the single screw extruder for sheaths. Then, from the twin screw extruder for the core and the single screw extruder for the sheath, the core sheath type die having a predetermined diameter is supplied at a predetermined temperature so as to have a predetermined mass ratio. The temperature when supplying the core-sheath die may be, for example, 200 ° C. or more and 290 ° C. or less. By extruding the material from a core-sheath die, a strand having a two-layer structure in which a sheath layer is laminated on the outer peripheral surface of the core material layer can be extruded. The strand extruded from the core-sheath die is cooled and cut into a predetermined length with a pelletizer, whereby a two-layer olefin resin pellet can be produced. The temperature for cooling the strand is not particularly limited as long as it is not higher than the melting point of the polyolefin resins (a) and (b).

  When the above-mentioned additives are contained in the pellets, the additives are premixed with the polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and a polyhydric alcohol, and then the biaxial core. You may supply to an extruder, or you may supply the said additive etc. to the single screw extruder for sheaths after mixing with polyolefin-type resin (b) previously.

  The shape of the two-layer structure olefin-based resin pellet according to the present invention is not particularly limited, and examples thereof include a cylinder, a prism, and the like, and a cylinder is preferable because it is easy to manufacture and easy to handle.

  The size of the two-layer olefin resin pellet according to the present invention is not particularly limited, and may be determined as appropriate according to the purpose. When the shape of the pellet is a cylinder as shown in FIG. 1, the diameter of the bottom surface of the cylinder may be 0.5 mm or more and 5 mm or less, and the length (the length in the direction perpendicular to the bottom surface) may be 1 mm or more and 10 mm or less. . The thickness of the sheath layer (the length in the radial direction of the bottom surface of the cylinder) is appropriately changed depending on the diameter of the core material layer and the ratio of the olefin resin composition (A) and the olefin resin composition (B). For example, it may be 0.05 mm or more and 1 mm or less.

[Utilization of 4.2 layer olefin resin pellets]
The two-layer olefin resin pellet according to the present invention can be melted, extruded into a desired shape, and stretched to produce extrudates such as fibers, sheets, and films. Further, the two-layer olefin resin pellets according to the present invention may be used as a master batch, and the two-layer olefin resin pellets and another resin composition may be previously melt-mixed and supplied to an extruder or the like. . For example, what melt | dissolved the said 2 layer structure olefin resin pellet is extruded to a sheet form or a film form, and it is good also as a sheet | seat or a film. Moreover, what melt | dissolved the said 2 layer structure olefin resin pellet may be extruded from the die | dye which becomes a desired fiber diameter, and it is good also as a fiber.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  Examples of the present invention will be described below, but the present invention is not limited to these examples without departing from the spirit of the present invention.

[Examples 1 to 11]
As a core material layer component (olefin resin composition (A)), from a pellet feeder, a linear low density polyethylene resin (MFR = 2) and an ethylene-methyl methacrylate copolymer (MFR = 7, copolymer) The content of methyl methacrylate in the mixture was supplied to a twin screw extruder for core (46 mm, L / D = 38.5). The total amount of the olefin resin composition (A) is 100% by mass, the linear low-density polyethylene resin is used in an amount of 0.55 to 72.2% by mass, and the ethylene-methyl methacrylate copolymer is 22.2 to 93. .89% by mass was used. Further, glycerin was supplied from the gear pump to the twin screw extruder. The glycerin was used so as to be 4.4 to 5.6% by mass when the total amount of the olefin resin composition (A) was 100% by mass. On the other hand, as the sheath layer component (olefin-based resin composition (B)), the same linear low-density polyethylene resin as described above was supplied to a sheath single-screw extruder (40 mm, L / D = 25).

  Subsequently, the core material layer component and the sheath layer component were supplied from each of the core twin screw extruder and the sheath single screw extruder to a core sheath die having six caps. Six strands extruded from the core-sheath die at a discharge rate of 20 to 40 kg / h were cooled in a cooling tank, and then cut by a pelletizer to have a diameter of 3φ × 3.5 mm and a sheath thickness of 0.25 mm. A two-layer olefin resin pellet was obtained.

Whether or not the polyhydric alcohol could be stably held in the two-layer structure olefin-based resin pellet was judged based on whether or not continuous operation was possible. The results were classified into the following four:
◎ ・ ・ ・ Strands do not break and stable continuous operation is possible.
○ ・ ・ ・ Strands sometimes break, but continuous operation is possible.
△ ... Strand condition is improved, but unstable operation,
×: Continuous operation is not possible.

  Note that “impossible continuous operation” means that a stable strand cannot be extruded from the core-sheath die, and pellets cannot be formed. Further, “strand state is improved” means that the frequency of strand breakage is improved as compared with the case where “continuous operation is impossible”.

[Comparative Examples 1-5]
In Comparative Examples 1 and 2, the core material layer was formed using only the linear low density polyethylene resin and glycerin without using the ethylene-methyl methacrylate copolymer. In addition, Comparative Example 1 was formed as a single-layer pellet having only a core material layer, and Comparative Example 2 was formed as a two-layer pellet including a core material layer and a sheath layer. Moreover, the comparative example 3 was formed as a single layer pellet only of the core material layer using a linear low density polyethylene resin, an ethylene-methyl methacrylate copolymer, and glycerin. Comparative Examples 4 and 5 were formed as two-layer pellets composed of a core material layer using only an ethylene-methyl methacrylate copolymer and glycerin and a sheath layer using a linear low-density polyethylene resin. The discharge rate when extruding the strand from the core-sheath die was 20 kg / h. In addition, when forming as a single layer pellet, the core material component was supplied from the twin screw extruder for the core to an ordinary die die of the die without using the single screw extruder for the sheath, and the strand was extruded. Except for the above points, pellets were produced under the same conditions as in Examples 1 to 11, and the availability of stable operation was evaluated.

[Results of Examples and Comparative Examples]
Table 1 shows the production conditions of the pellets of Examples 1 to 11 and Comparative Examples 1 to 5 and the evaluation results of the stable operation. In addition, the numerical value described in the row | line | column of the linear low density polyethylene resin of a core material layer, an ethylene-methyl methacrylate copolymer, and glycerol is each with respect to the core material layer (olefin resin composition (A)) whole quantity. Content (mass%). Moreover, the numerical value described in the row | line | column of a sheath layer has shown the quantity of the sheath layer by mass ratio when the quantity of a core material layer is set to 100.

  In Examples 1-11, the pellet by which the polyhydric alcohol was hold | maintained was able to be formed. Among them, in Examples 7 to 11, pellets could be produced by a stable operation, and in particular, in Examples 7 and 9 to 11, the strands were not broken and a particularly stable continuous operation could be performed.

  On the other hand, when a single layer pellet was produced, continuous operation was impossible (Comparative Examples 1 and 2). In particular, in Comparative Example 2, three components of linear low-density polyethylene resin, ethylene-methyl methacrylate copolymer, and glycerin were included in the core material layer as in Examples 1 to 11, but Operation was impossible. Moreover, even when it was manufactured as a two-layer structure olefin-based resin pellet, if any of the above three components was not included in the core material layer, stable operation was not possible (Comparative Example 3). And 4). In Comparative Example 5, although the pellets in which the polyhydric alcohol was retained could be formed, the strands were broken more frequently than in Examples 1 to 11, and the operation was more unstable.

  INDUSTRIAL APPLICABILITY Since the present invention can be suitably used as a resin composition for producing fibers and sheets, or a pellet for a master batch for producing the resin composition, it can be used in a wide range of industries that handle resins. Is possible. For example, since the masterbatch pellets can be used for the production of foamed sheets and the like, they can be used in industries related to cushioning packaging materials and the like.

1 Core material layer 2 Sheath layer

Claims (8)

The olefin resin composition (A) is a core material layer, and the olefin resin composition (B) is laminated on the outer peripheral surface of the core material layer as a sheath layer.
The olefin resin composition (A) includes a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and a polyhydric alcohol.
The olefin resin composition (B) contains a polyolefin resin (b), and is a two-layer olefin resin pellet.   2. The two-layer structure olefin according to claim 1, wherein the content of the polyolefin resin (a) with respect to the total amount of the olefin resin composition (A) is 0.1% by mass or more and 55% by mass or less. Resin pellets.   The content of the copolymer of the ethylene and carboxylic acid ester with respect to the total amount of the olefin resin composition (A) is 40% by mass or more and 99% by mass or less. Two-layer olefin resin pellets.   Content of the said polyhydric alcohol with respect to whole quantity of the said olefin resin composition (A) is 0.1 mass% or more and 10 mass% or less, The any one of Claims 1-3 characterized by the above-mentioned. Two-layer olefin resin pellets.   The two-layer structure according to any one of claims 1 to 4, wherein a mass ratio of the olefin resin composition (A) to the olefin resin composition (B) is 10: 1. Olefin resin pellets.   The two-layer structure olefin resin pellet according to any one of claims 1 to 5, wherein the copolymer of ethylene and a carboxylic acid ester is an ethylene-methyl methacrylate copolymer.   The two-layered olefin resin pellet according to any one of claims 1 to 6, wherein the polyhydric alcohol is glycerin or ethylene glycol. Production of two-layer olefin resin pellets comprising a step of laminating the olefin resin composition (A) as a core material layer and laminating the olefin resin composition (B) as a sheath layer on the outer peripheral surface of the core material layer A method,
The olefin resin composition (A) includes a polyolefin resin (a), a copolymer of ethylene and a carboxylic acid ester, and a polyhydric alcohol.
The said olefin resin composition (B) contains polyolefin resin (b), The manufacturing method of the two-layer structure olefin resin pellet characterized by the above-mentioned.

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