JP2001207335A - Fibrillar material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive and new fibrillar material excellent in chemical and heat resistances, strength, high modulus of elasticity, adhesion and electrical insulating properties which cannot be achieved by a known fibrillar material and capable of especially exhibiting the performances when formed into a composite material. SOLUTION: This fibrillar material is characterized in that the fibrillar material is composed of a polyketone comprising >=90 mol% of a recurring unit represented by the following formula (1) and the specific surface area is >=0.3 m2/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fibril-like material comprising an aliphatic polyketone. More specifically, it is excellent in chemical resistance, heat resistance, strength, high elastic modulus, adhesiveness, and electrical insulation, and can exhibit these properties especially when it is made into a composite material, and is a fibril made of inexpensive aliphatic polyketone. About things.

[0002]

2. Description of the Related Art Conventionally, paper is mainly made of wood pulp, and is widely used in large quantities. However, paper made from wood pulp is inferior in properties such as water resistance, heat resistance, and electrical insulation. For example, when used as insulating paper for electrical equipment, the performance, size, and weight of these equipment have been reduced. In this case, the required performance cannot be satisfied. In recent years, fibrils such as pulp and fibrid obtained from synthetic polymers have become chemically resistant, heat resistant,
Attention has been paid to a new paper material that has excellent electrical insulation properties and compensates for the drawbacks of wood pulp, and various proposals have been made.

For example, Japanese Patent Publication No. 35-11851 discloses a fibril-like product of a polyamide polymer, a polyester polymer, a polyacrylonitrile polymer, an elastomer polymer and a vinyl polymer, and its production method and application to paper. Is described. The fibrids disclosed here are superior to wood pulp in chemical resistance and heat resistance, but are insufficient for more severe use conditions. JP-B-43-20421 discloses a fibril-like aromatic polyamide polymer. Although this product shows more excellent heat resistance and electrical properties, it still has a weak point against the action of severe chemicals, particularly hydrolysis and oxidation at high temperatures.

Further, in recent years, asbestos substitute materials such as clutch facings, brake linings, gaskets, sealants, coating agents and the like have been developed by using fibrils of aromatic polyamide polymers and utilizing their excellent heat resistance and mechanical properties. Demand for printed circuit board materials for personal computers is growing rapidly. However,
The aromatic amide polymer has a high production cost due to the expensive raw material monomer, and also has an essential problem in chemical resistance and electrical insulation derived from the molecular structure.

[0005]

The problem to be solved by the present invention is to improve the chemical resistance, heat resistance, strength, high elastic modulus, adhesiveness and electric insulation, which have not been achieved by known fibril-like materials. It is an object of the present invention to provide a novel fibril-like material which is excellent, in particular, can exhibit these properties when made into a composite material, and is inexpensive.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to solve the above-mentioned problems. As a result, the aliphatic polyketone is fibrillated to have a specific specific surface area. The present inventors have found the possibility of completely solving the problem, and as a result of further study, have reached the present invention. That is, the present invention provides a fibril-like material comprising a polyketone having a repeating unit represented by the following formula (1) of 90 mol% or more and a specific surface area of 0.3 m ² / g or more. Things.

[0007]

Embedded image

The fibril-like material of the present invention comprises (1) a polyketone, and (2) fibrous, thin-film or ribbon-like particles having different sizes, or irregular fine particles having a combination of these shapes. (3) The largest of the three-dimensional dimensions of most particles is much larger than the other two smaller dimensions, and preferably the smaller two dimensions are 10
not more than μm, (4) formed into a fibrous, thin film or ribbon-like structure having a large number of tentacle-like projections, preferably capable of mechanically entanglement with other particles; and (5)
Pulp-like particles characterized by having much greater water holding capacity than ordinary fibers made from the same polymer by ordinary spinning processes.

The fibrils of the present invention have a large specific surface area and the ability to entangle when deposited on a conventional papermaking screen to produce a paper-like structure, at which time entanglement is obtained. The paper-like structure retains its shape when wet after dehydration and after drying, and provides sufficient paper strength to support its own weight. Also, in a composite material which is mixed with a resin, concrete, metal or the like and molded as a single body, a high degree of fine dispersion is achieved, and the resulting composite material exhibits excellent moldability, rigidity and chemical resistance.

In the polyketone constituting the fibril-like material of the present invention, 90 mol% or more of the repeating unit is a polyketone represented by the above formula (1). Since this polyketone structure does not have a hydrogen bond in the molecule, it is possible to impart excellent electrical insulation to the obtained fibril-like material. In the range of less than 10 mol%, preferably less than 3 mol%, more preferably less than 1 mol%, repeating units other than the repeating unit represented by the above formula (1), for example, those represented by the following formula (2) May be contained.

[0011]

Embedded image

In the formula, R represents a carbon atom other than ethylene having 1 to 30 carbon atoms.
Organic groups such as propylene, butylene, 1-phenylethylene and the like. Some or all of these hydrogen atoms are a halogen group, an ester group, an amide group,
It may be substituted with a hydroxyl group or an ether group. Of course, R may be two or more types, and for example, propylene and 1-phenylethylene may be mixed. From the viewpoint that high strength and high elastic modulus can be achieved and stability at high temperature is excellent, 98 mol% or more of the repeating unit is preferably a polyketone represented by the above formula (1), and most preferably 100 mol%. %.

If necessary, these polyketones may contain additives such as antioxidants, radical inhibitors, other polymers, matting agents, ultraviolet absorbers, flame retardants, metal soaps and the like. Good. The specific surface area of the fibril-like material of the present invention needs to be 0.3 m ² / g or more. 0.
If it is less than 3 m ² / g, the dispersibility is poor, the strength as paper is low, and the reinforcing effect as asbestos material is not exhibited. It is preferably at least 0.7 m ² / g, more preferably at least 2 m ² / g, most preferably at least 5 m ² / g. The upper limit of the specific surface area of the fibril-like material is not particularly limited. However, if the specific surface area is too high, coagulation becomes severe and handling becomes difficult, so that the specific surface area is usually 100 m ² / g or less.
It is preferably at most 50 m ² / g.

The fibril of the present invention has a crystallinity of 3
It is preferably 0% or more. When the crystallinity is in this range, paper and composite materials produced using the fibril-like material exhibit excellent mechanical strength. When the degree of crystallinity is less than 30%, the reinforcing effect is not sufficiently exhibited. Preferably, it is at least 50%, more preferably at least 60%. The fibril-like material of the present invention can be produced by subjecting a polyketone dispersion to mechanical treatment. The form of the polyketone dispersed in the dispersion is not particularly limited, such as cut fibers, long fibers, and powders. However, cut fibers are preferable because they easily fibrillate when subjected to mechanical treatment. From the viewpoint of easy dispersion, a polyketone solution obtained by adding a polyketone solution to a poor solvent to precipitate a part or all of the polyketone and subjecting it to mechanical treatment is preferable.

The cut fiber has an intrinsic viscosity of 1.5 dl.
/ G or more, is wet-spun, and then hot drawn three times or more to obtain a long fibrous drawn yarn, and is then cut using a known chopped strand such as a cutter or scissors.
What cut into 5-200 mm, preferably 0.5-50 mm has high strength and high elasticity, and since the molecules are highly oriented, it is easy to fibrillate, so that fibrils having a high aspect ratio are easily formed. It is particularly preferable in that it can be obtained.

As the solvent used for wet spinning, JP-A No.
For example, hexafluoroisopropanol, m-cresol, resorcinol, hydroquinone and mixtures thereof disclosed in JP-A-12413, JP-A-4-228613 and JP-A-4-505344 can be used. These organic solvents are not industrially preferable because they have problems in toxicity, odor and flammability.
Particularly preferred are aqueous solutions of nitrate, calcium salt, isocyanate salt and the like, and nitric acid, which are proposed by the present inventors, because they have low toxicity, are non-flammable, and have high solubility of polyketone (for example, Japanese Patent Application No. 10-108). 236595). In addition, the polyketone fiber obtained by melt spinning may be cut and used, but the fiber obtained by melt spinning has a low molecular orientation, so the problem that fibrillation is less likely than that of fiber obtained by wet spinning is problematic. is there.

The polyketone dissolved in the above-mentioned solvent may be added to a poor polyketone solvent to precipitate a part or all of the polyketone. In this case, the solvent is preferably an aqueous solution of a zinc salt, a calcium salt, an isocyanate salt or the like, or nitric acid, and the polymer concentration in the solution is preferably 0.01 to 70% by weight. The poor solvent is not particularly limited, but water or any aqueous solution is particularly preferred from the viewpoints of toxicity, nonflammability, and price.

The fibrous, powdery, or film-like polyketone obtained as described above can be dispersed in any organic or inorganic solvent. Although there is no particular limitation on the dispersion used, polyketone is particularly preferably dispersed in an aqueous solvent since it is completely inexpensive and safe and completely wets with water or an aqueous solution and can achieve a high degree of dispersion. The amount of the polyketone in the dispersion is not particularly limited, but is usually 0.1 to 100% by weight from the viewpoint of dispersibility and ease of transportation.

By subjecting the thus obtained polyketone dispersion to mechanical treatment, the polyketone fibril of the present invention can be obtained. The mechanical treatment is not particularly limited as long as it has a power of finely crushing the dispersed polyketone, and examples thereof include stirring, jetting, friction, shearing by impact, and beating. Devices that perform these mechanical processes include:
Although there is no particular limitation, a mixer, a stirrer, a homogenizer, a kneader, a pump, a ball mill, a rotary cutter and the like can be used. When a polyketone solution is added to a poor solvent to precipitate a polyketone, the above mechanical treatment may be added during precipitation and / or precipitation.

The fibril-like product of the present invention thus obtained preferably has an appropriate amount of water before use from the viewpoint of storage stability, maintenance of dispersibility and suppression of static electricity.
The water content is usually from 0.01 to 200%, particularly preferably from 2 to 60%. The fibril-like material thus obtained can be developed for various uses. Particularly useful as one of the applications is a sheet structure, a filter, a battery separator,
It can be applied to composite materials reinforced with resin, cement, metal and the like. The sheet structure has a structure in which the fibril-like materials of the present invention are laminated, and a part or all of the fibril-like materials may be partially melted and fused as necessary, and a known structure may be used. It may be bonded using an adhesive. The thickness of such a structure is usually 100 μm to 10 mm, and the basis weight is usually 0.01 to 200 g / m ² .

As a preferable method for producing a sheet-like material obtained from the fibril-like material of the present invention, a slurry containing the fibril-like material of the present invention is prepared, and then the slurry is removed from the slurry by removing the liquid using a filter. This is a method of forming a sheet and then drying the wet sheet. The slurry is preferably a slurry in which the fibril-like substance is dispersed in water from the viewpoint of operability and safety, and the content of the fibril-like substance in the slurry can be arbitrarily set.

As the filter, a known filter such as a metal or resin mesh or a filter may be used. In order to continuously produce a sheet-like material, a belt-shaped filter is preferable. For removal, the belt may be suctioned from underneath or heated. The sheet obtained is subsequently dried. The drying temperature is usually 50 to 400
° C. The sheet-like material thus obtained may be used as it is, or may be laminated or partially bonded using a press or the like. The temperature of the press surface is 80 to 300 ° C,
The pressing pressure is 1 to 5000 kg / cm ² .

The fibril-like material of the present invention can be used as a composite material by mixing it with resin, cement, metal or the like. The resulting composite material is a material having high rigidity and high chemical resistance, reflecting the adhesiveness, high strength, high elastic modulus, and chemical resistance of the fibril-like material. The content of the fibril-like material of the present invention in the composite material can be arbitrarily set,
It is usually at least 1% by weight. The resin that can be used is not particularly limited, and includes, for example, known phenol resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, rubbers, and the like. If necessary, other fillers may be used in combination.

[0024]

The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention. The measuring method of each measured value used in the description of the embodiment is as follows. (1) Intrinsic viscosity Intrinsic viscosity [η] was determined based on the following definition formula. [Η] = lim (T−t) / (t · C) Unit: dl / g C → 0 t and T in the definition formula were dissolved in a hexafluoroisopropanol solvent having a purity of 98% or more and the hexafluoroisopropanol. Flow time of a dilute solution of polyketone at 25 ° C. through a viscosity tube. C is the solute weight value in grams per 100 ml.

(2) Specific Surface Area The specific surface area was determined from the amount of nitrogen absorbed by the BET specific surface area method using a flow soap 2300 manufactured by Micromeritex. If the sample is in a water-containing state,
The measurement was performed after removing water under vacuum. (3) Water content The water content was determined according to the following equation.

(4) Crystallinity The melting point was measured by using a DSC (differential scanning thermal analyzer).
It was calculated from the calorific value ΔH (J / g) calculated from the maximum endothermic peak area obtained in the range of 00 to 300 ° C. using the following equation. Here, 225 J / g is the heat of fusion of perfect crystals. Crystallinity = (ΔH / 225) × 100 (%) (5) Strength, Elongation and Elasticity of Fiber The strength and elongation of the fiber were measured according to JIS-L-1013.

[0027]

Example 1 8% by weight of an ethylene / carbon monoxide alternating copolymer ([η] = 5.3 dl / g), zinc chloride 6
0% by weight, 10% by weight of sodium chloride, 22% by weight of pure water
Adjust the polymer solution of the composition of, while maintaining at 80 ℃,
Discharge rate 20g / mi from 50 holes of 0.1mm diameter nozzle
n, extruded with an air gap length of 10 mm, and coagulated with water, which is a non-solvent for the polymer, to form a fiber.
Then, the fibers were passed through a 2% sulfuric acid aqueous bath to completely remove the zinc chloride, and sulfuric acid was removed with a water-washing roll, followed by winding. The winding speed was 6 m / min. Then, at 200 ° C
, And stretched 6 times on a hot plate between non-heated rolls at a stretching temperature of 240 ° C, and further stretched 2 times at 268 ° C to obtain a 75 d / 50f polyketone fiber. The obtained fiber had a strength of 15.2 g / d, an elongation of 5%, and an elastic modulus of 340 g / d. The crystallinity was 75%.

The obtained polyketone fiber was cut to a fixed length of 5 mm and pulverized with a PF1 mill manufactured by Kumagai Riki Kogyo Co., Ltd. to obtain a fibril having a specific surface area of 6.3 m ² / g. There was no change when the obtained fibril-like material was immersed in concentrated sulfuric acid at 20 ° C. for 10 hours. 6.0 g of fibril was dispersed in 3 liters of water. The fibrils were uniformly dispersed without repelling water. Using such a dispersion, 15 cm × 15
The paper was made to the size of cm. After squeezing and dehydrating at 10 kg / cm ^2, it was dried at 60 ° C. Laminated four dried papers, 50
10 minutes at 170 ° C. under a pressure of 0 kg / cm ² , 24
It was hot pressed at 0 ° C. for 5 minutes. The paper thus obtained was strong. 90% of this paper in an autoclave
There was no change in toughness when heat treated at 200 ° C. for 60 minutes in a relative humidity atmosphere.

[0029]

Comparative Example 1 The specific surface area was reduced to 0.23 by shortening the pulverizing time.
An m ² / g fibril was obtained according to Example 1. An attempt was made to produce a paper-like material in the same manner as in Example 1, but the fibril-like materials could not be joined together.

[0030]

Comparative Example 2 Instead of polyketone, specific surface area 6.5 m ²
/ G of poly (paraphenylene terephthalamide) pulp was immersed in concentrated sulfuric acid as in Example 1, and the pulp became very brittle. Further, the pulp became very brittle even when subjected to wet heat treatment in the same manner as in Example 1. Further, a paper-like material was prepared in the same manner as in Example 1 using this pulp. Although the obtained paper-like material was tough, it became very brittle when heat-treated at 200 ° C. for 60 minutes in a 90% relative humidity atmosphere in an autoclave, and could not retain the shape of the paper-like material.

[0031]

Example 2 8% by weight of an ethylene / carbon monoxide alternating copolymer ([η] = 5.3 dl / g), zinc chloride 6
0% by weight, 10% by weight of sodium chloride, 22% by weight of pure water
Was stirred vigorously for 5 minutes with a household mixer previously containing 300 ml of water. The resulting fibril was filtered off and washed repeatedly with water. The specific surface area of the fibril-like material thus obtained is 3.
8 m ² / g, crystallinity was 56%. The water content was 45%. Using the obtained fibril-like material,
When a paper-like material was prepared in the same manner as in Example 1, a tough product was obtained.

[0032]

EXAMPLE 3 An ethylene / propylene / carbon monoxide alternating copolymer terpolymer having an intrinsic viscosity of 1.8, in which propylene was copolymerized at 6% by weight, was melted at 250 ° C. using an extruder, and 0.23 mm × 36. Extruded from individual spinnerets, 100
The film was wound at 0 m / min. The obtained undrawn yarn is drawn 15 times, and has a strength of 13 g / d, an elongation of 6%, and an elasticity of 140 g / d.
Thus, a drawn yarn d was obtained. In the same manner as in Example 1, the cut fiber was fibrillated to obtain a fibril-like material having a specific surface area of 3.8 m ² / g.

The absolute dry weight of the fibrils is 6.25.
g of this fibril having a water content of 35%
It was dispersed in 1 liter of water at 000 rpm for 3 minutes. Next, a wire mesh of 80 mesh is 25cm x 25cm.
Paper. Thereafter, drying was performed at 120 ° C. for 2 hours to obtain a paper-like material having a basis weight of 100 g / m ² . A test piece of 50 mm × 100 mm was cut out from the polyketone paper thus obtained, and then a modified resol type phenol resin PR-SCI was cut out.
-3 (trade name, manufactured by Sumitomo Durez) is diluted and mixed with a 22.5% methanol solution. After impregnating this resin liquid so that the weight ratio of paper / resin becomes 44.5 / 56.5,
Drying was performed at 50 ° C. for 20 minutes to prepare an impregnated prepreg.

The above two prepregs are laminated, and 0.6 mm
Is press-formed at 180 ° C. and 6 kg / cm ^{2 for} 10 minutes, and then pressed in an oven for 18 minutes.
Treated at 0 ° C. for 2 hours to cure. The obtained composite material was excellent in rigidity. In water at 96 ° C, 1
There was no change in rigidity even after heating for 0 hours.

[0035]

The fibril-like material of the present invention is excellent in chemical resistance, heat resistance, strength, high elastic modulus, adhesiveness, and electric insulation, which have not been achieved by known fibril-like materials, and is particularly suitable for composite materials. It is a novel fibril-like material that can exhibit these performances at low cost and is inexpensive. In particular, it is a completely new fibril-like material that exhibits excellent performance when used in various industrial materials such as paper, asbestos replacement, and printed circuit boards.

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Claims (7)

[Claims] 1. A fibril-like material comprising a polyketone having a repeating unit represented by the following formula (1) in an amount of 90 mol% or more and a specific surface area of 0.3 m ² / g or more. Embedded image 2. The fibril-like material according to claim 1, wherein the water content is 0.01 to 200%. 3. The method for producing a fibril-like product according to claim 1, wherein a dispersion of the polyketone in which the repeating unit represented by the following formula (1) is 90 mol% or more is subjected to mechanical treatment. Embedded image 4. The method for producing a fibril-like substance according to claim 3, wherein a solution of the polyketone is added to the poor solvent, and the dispersion is a dispersion in which part or all of the polyketone is precipitated. 5. A sheet structure comprising the fibril-like material according to claim 1. 6. A wet sheet is formed from the slurry by preparing a slurry containing the fibril-like material according to claim 1 or 2, and then performing dewatering using a filter, and then drying the wet sheet. The method for producing a polyketone sheet according to claim 5, comprising: 7. A composite material comprising at least 1% by weight or more of the fibril-like material according to claim 1 or 2.