JP7090385B2 - Fiber-reinforced thermoplastic composite materials, fiber-reinforced thermoplastic resin compositions, and their moldings. - Google Patents

Description

The present invention relates to a fiber-reinforced thermoplastic composite material composed of short organic fibers and a thermoplastic resin. More specifically, the present invention relates to a fiber-reinforced thermoplastic composite material suitable as a molding material.

It has long been practiced to compound short fibers as a reinforcing material into rubber, plastic, or a thermoplastic elastomer having intermediate properties between rubber and plastic (for example, Non-Patent Document 1).

As the short fibers, synthetic fibers such as polyester, polyamide and aramid, and inorganic fibers such as glass fiber and carbon fiber are used.

For example, Patent Document 1 describes 100 parts by weight of a mixed resin of a styrene-based thermoplastic elastomer and ionomer, 5 to 10 parts by weight of Kevlar pulp (a short fiber obtained by finely cutting aramid short fibers), and 6 parts by weight of a pigment. It is disclosed that a cover composition containing a portion is extruded by a twin-screw kneading extruder, and a hemispherical shell-shaped half shell is injection-molded using the composition to produce a golf ball.

Patent Document 2 describes a thermoplastic material (polyester-based thermoplastic elastomer resin, polyolefin-based thermoplastic elastomer resin or polypropylene resin) and aramid short fibers recovered from used aramid gloves having an aramid short fiber content of 10. It is disclosed that a fastener is produced by melt-kneading and extruding the extruded composition to about 20% by weight and injection molding the extruded composition.

Composite materials using short fibers as reinforcing materials are not as strong as composite materials reinforced with long fibers, but the elastic modulus and fiber orientation can be controlled, and anisotropic composite materials can be easily obtained and processed. In terms of surface, it can be easily molded with a general-purpose rubber processing machine such as an open roll, a Banbury mixer, or an extruder, so that there is an advantage that mold design becomes extremely easy. However, since it is recognized that the reinforcing effect tends to decrease due to the cutting of the staple fibers when the thermoplastic material and the staple fibers are kneaded, a thermoplastic composite material having a higher reinforcing effect is required.

JP-A-2002-136618 (Examples, Table 1, etc.) Japanese Unexamined Patent Publication No. 2004-346954 (Example 1 etc.)

Asahiro Hase, Koichi Yamaguchi: Journal of the Japan Rubber Association vol69 p615 (1996)

An object of the present invention is to provide a fiber-reinforced thermoplastic composite material having a high reinforcing effect on a thermoplastic material.

That is, the present invention is as follows.

(1) Aramid fiber staples (excluding pulp),
It is composed of a polyester-based thermoplastic elastomer having a breaking elongation (ISO527 compliant) of 200% or more in a tensile test.
The stress-strain curve (SS curve) in the tensile test conforming to ISO527 is
(A) If there is an upper yield point, the stress at the upper yield point,
(B) If the stress does not show a clear upper yield point and the stress increases even after yielding, the stress at 40% strain,
When the yield strength is
The fiber reinforcement is characterized in that the yield strength is 1.3 times or more the yield strength (ISO527 compliant) of the polyester-based thermoplastic elastomer as the base material, and the tensile elongation at break is 200% or more. Thermoplastic composite material.
(2) The fiber-reinforced thermoplastic composite material according to (1) above, wherein the tensile yield strength in the tensile test conforming to ISO527 is 10 MPa or more.
(3) The fiber-reinforced thermoplastic composite material according to (1) or (2) above, wherein the content of the short fiber in the fiber-reinforced thermoplastic composite material is 1 to 40% by mass.
(4) The fiber-reinforced thermoplastic composite material according to any one of (1) to (3) above, wherein the aramid fiber is a polyparaphenylene terephthalamide fiber impregnated with an epoxy group-containing compound in the fiber skeleton.
(5) The fiber-reinforced thermoplastic composite material according to any one of (1) to (4) above, wherein the average fiber length of the staple fibers is 5 mm or less.
(6) A molded product obtained by molding the fiber-reinforced thermoplastic composite material according to any one of (1) to (5) above.
(7) A fiber-reinforced thermoplastic resin composition in which the fiber-reinforced thermoplastic composite material according to any one of (1) to (5) above is blended with a thermoplastic resin and the amount of short fibers is 1 to 30% by mass. ..
(8) The thermoplastic resin is a thermoplastic elastomer resin, a polyolefin resin, a polyvinyl chloride resin, a polystyrene resin, an acrylic resin, a polycarbonate resin, a polyester resin, an ABS resin, an AS resin, a polyoxymethylene resin, a nylon resin, or a polyphenylene oxide. At least one selected from resins, polyphenylene sulfide resins, polyether sulfone resins, polyamideimide resins, polyether ether telketone resins, polyether ketone ketone resins, polyetherimide resins, ionomer resins and alloy resins thereof. The fiber-reinforced thermoplastic resin composition according to (7) above.
(9) Further contains an additive, and the additive is a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antioxidant, a lubricant, a nucleating agent, a plasticizer, a coloring inhibitor, a matting agent, an antibacterial agent, and an extinguishing agent. The fiber-reinforced thermoplastic resin composition according to (7) or (8) above, which is at least one selected from a odorant, a flame retardant, an antistatic agent, a mold release agent, a filler, a pigment and a dye.

According to the present invention, it is possible to provide a thermoplastic fiber-reinforced composite material having excellent mechanical properties. The fiber-reinforced thermoplastic composite material is particularly excellent in tensile yield strength, so that it can withstand deformation under load. Moreover, since it has an excellent flexural modulus, it has good cushioning properties.
The fiber-reinforced thermoplastic composite material for molding of the present invention can be used as a molding material as it is, by adding an additive as necessary, or by blending it with another thermoplastic resin or the like, and also having fiber-reinforced thermoplasticity. It can also be used as a master batch of the resin composition.

The molded product obtained by molding the fiber-reinforced thermoplastic composite material and the fiber-reinforced thermoplastic resin composition of the present invention is used for various applications requiring high tensile yield strength and tensile elastic coefficient, for example, automobile tires and motorcycle tires. , Aircraft tires, automobile interior parts, housings for electrical appliances, office supplies, daily necessities, chemical filling containers, refrigeration containers, packaging containers, etc.

The fiber-reinforced thermoplastic composite material according to the present invention is composed of short fibers of organic fibers and a thermoplastic material.

In the present invention, the thermoplastic material serves as a base material for the fiber-reinforced thermoplastic composite material. The elongation at break in the tensile test of the thermoplastic material is preferably 200% or more. As a result, the tensile elongation of the composite material after fiber reinforcement is maintained until after the yield point, a good tensile yield strength can be exhibited, and it becomes possible to withstand deformation under load. The elongation at break in the tensile test of the thermoplastic material as the base material is more preferably 300% or more, still more preferably 400% or more. The breaking elongation of the thermoplastic material is a value measured according to JIS K7113: 1995.

As the thermoplastic material, a thermoplastic resin, a thermoplastic elastomer, or the like can be used. The thermoplastic material is not particularly limited, and is, for example, a thermoplastic resin such as a polyethylene resin, an ethylene-propylene copolymer resin, an ethylene-vinyl acetate copolymer resin, a polybutylene terephthalate resin; a polyolefin resin, a polyester resin, or the like. Thermoplastic elastomer; or a thermoplastic resin composition such as a copolymer resin or a modified resin thereof, or a combination of one or more selected from these resins can be used.

Among the thermoplastic materials, the thermoplastic elastomer is preferable in that various processing methods can be adopted and the durability against repeated deformation is excellent.

Examples of the polyolefin-based thermoplastic elastomer include copolymers of two or more types of monomers selected from α-olefins such as ethylene, propylene, 1-butene, 1-pentene, and 1-octene, and their copolymer weights. One of the combined products may be used alone or two or more of them may be used in combination. For example, ethylene-propylene copolymer (EPR), ethylene-1-butene copolymer (EBR), ethylene-1-pentene copolymer, ethylene-1-octene copolymer (EOR), propylene-1-butene. Examples thereof include a copolymer (PBR), a propylene-1-pentene copolymer, and a propylene-1-octene copolymer (POR).

Among thermoplastic elastomers, it consists of crystalline polymer chains (hard segments) and amorphous polymer chains (soft segments), and has mechanical properties (high load resistance, toughness, bending) not only at room temperature but also at high temperatures. Polyester-based thermoplastic elastomers are preferable because they have high fatigue resistance), flexibility, and elasticity.

The polyester-based elastomer has a block copolymer weight composed of a hard segment (a1) composed of a crystalline aromatic polyester unit and a soft segment (a2) composed of an aliphatic polyether unit and / or an aliphatic polyester unit. Coalescence is mentioned.

The hard segment (a1) is preferably formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.
Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracendicarboxylic acid, and diphenyl-4,4'-dicarboxylic acid. , Diphenoxyetanedicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 5-sulfoisophthalic acid, sodium 3-sulfoisophthalate and the like.

It is preferable to use two or more of the above acid components, and examples thereof include combinations of terephthalic acid and isophthalic acid, terephthalic acid and dodecandionic acid, and terephthalic acid and dimer acid. By using two or more kinds of acid components, the crystallinity of the hard segment can be lowered, flexibility can be imparted, and thermal adhesion and melt mixing properties with other thermoplastic resins are also improved. do.

Specific examples of the diol include diols having a molecular weight of 400 or less, for example, aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol. , 1-Cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, alicyclic diols such as tricyclodecanedimethanol, and xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxy) diphenylpropane, 2,2'-Bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxyethoxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane , 4,4'-Dihydroxy-p-terphenyl, and 4,4'-dihydroxy-p-quarterphenyl and other aromatic diols are preferred. Such diols can also be used in the form of ester-forming derivatives such as acetyls, alkali metal salts and the like.

The hard segment (a1) of the polyester block copolymer is preferably 1 with polybutylene terephthalate units derived from terephthalic acid and / or dimethylterephthalate and 1,4-butanediol, and isophthalic acid and / or dimethylisophthalate. , 4-Butandiol consists of polybutylene isophthalate units derived from.

The hard segment (a1) of the polyester block copolymer is more preferably polybutylene terephthalate derived from terephthalic acid and / or dimethylterephthalate, isophthalic acid and / or dimethylisophthalate, and 1,4-butanediol. / It consists of an isophthalate unit.

The soft segment (a2) of the polyester block copolymer is composed of an aliphatic polyether unit and / or an aliphatic polyester unit.
Examples of the aliphatic polyether as a constituent unit include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and poly. Examples thereof include ethylene oxide addition polymers of (propylene oxide) glycols and glycols of copolymers of ethylene oxide and tetrahydrofuran.
Examples of the aliphatic polyester as a constituent unit include poly (ε-caprolactone), polyenant lactone, polycaprilolactone, polybutylene adipate, and polyethylene adipate.
Among these aliphatic polyethers and / or aliphatic polyesters, from the elastic properties of the obtained polyester block copolymer, poly (tetramethylene oxide) glycol, an ethylene oxide adduct of poly (propylene oxide) glycol, and ethylene oxide It is preferable to use the copolymer glycol of tetrahydrofuran, poly (ε-caprolactone), polybutylene adipate, polyethylene adipate and the like. Among these, poly (tetramethylene oxide) glycol, ethylene oxide adduct of poly (propylene oxide) glycol, and copolymer glycol of ethylene oxide and tetrahydrofuran are particularly preferable.
The number average molecular weight of these soft segments is preferably about 300 to 6,000 in the copolymerized state.

The melting point of the polyester block copolymer is preferably less than 210 ° C, more preferably less than 200 ° C, still more preferably less than 190 ° C, from the viewpoint of energy cost in processing the fiber-reinforced thermoplastic composite material. More desirable.
Here, the melting point is Tm ₁ after observing the heat absorption peak temperature (Tm ₁ ) observed when the polymer that has been polymerized is measured at a temperature rise condition of 20 ° C./min from room temperature in the differential scanning calorimetry. The heat absorption peak temperature (Tm ₂ ) observed when the temperature is maintained at + 20 ° C. for 5 minutes, the temperature is once cooled to room temperature under a temperature decrease condition of 20 ° C./min, and then the measurement is performed again under a temperature rise condition of 20 ° C./min. Is defined as.

The copolymerization amount of the soft segment (a2) of the polyester block copolymer is usually 5 to 80% by mass, preferably 10 to 10 to 80% by mass when the total of the hard segment (a1) and the soft segment (a2) is 100% by mass. It is 75% by mass. If it is less than 5%, the elongation of the polyester block copolymer at tensile break will decrease, and the desired mechanical properties cannot be obtained. On the other hand, if it exceeds 80%, the crystallinity deteriorates and the cooling time at the time of molding becomes long (the cycle time becomes long), which is not preferable.

The polyester block copolymer can be produced by a known method. Specific examples thereof include, for example, a method of subjecting a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol and a low melting point polymer segment component to an ester exchange reaction in the presence of a catalyst, and polycondensing the obtained reaction product. , Dicarboxylic acid, excess amount of glycol and low melting point polymer segment component can be subjected to an esterification reaction in the presence of a catalyst, and the obtained reaction product can be polycondensed. Among these, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol and a low melting point polymer segment component are subjected to a transesterification reaction in the presence of a catalyst and the obtained reaction product is polycondensed is preferable.

The polyester-based thermoplastic elastomer preferably contains 0.01 to 5.0 parts by mass of an antioxidant. Examples of the antioxidant include one or more selected from the group consisting of aromatic amine-based antioxidants, hindered phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Among them, aromatic amine-based antioxidants are preferably used.

As the organic fiber constituting the fiber-reinforced thermoplastic composite material of the present invention, the characteristics of the raw yarn are measured in accordance with JIS L1013 8.5 because of its high tensile strength and excellent reinforcing effect on the thermoplastic material. Highly strong organic fibers having a tensile strength of 18 cN / dtex or more are preferable. The tensile strength is more preferably 20 cN / dtex or more, still more preferably 21 cN / dtex or more.

Examples of such organic fibers include aramid fibers (total aromatic polyamide fibers), total aromatic polyester fibers, polyparaphenylene benzoxazole fibers, polyketone fibers, cellulose nanofibers and the like. Among these organic fibers, aramid fibers are preferable.

In the present invention, the aramid fiber is a fiber having at least one divalent aromatic group which may be usually substituted in the repeating unit of the polymer forming the fiber, and is a fiber having at least one amide bond. If there is no particular limitation, it may be referred to as a total aromatic polyamide fiber or an aramid fiber, and the same or different one or more substitutions from the "optionally substituted divalent aromatic group". It means a divalent aromatic group which may have a group.

Examples of the aramid fiber include para-based aramid fiber and meta-based aramid fiber, but para-based aramid fiber having excellent tensile strength is preferable. Specifically, examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (DuPont, USA, manufactured by Toray DuPont Co., Ltd., trade name "Kevlar" (registered trademark)), copolyparaphenylene-3,4. '-Oxydiphenylene terephthalamide fiber (manufactured by Teijin Limited, trade name "Technora" (registered trademark)) and the like can be mentioned. Among these para-aramid fibers, polyparaphenylene terephthalamide fibers are particularly preferable.

In the present invention, it is also possible to use an aramid fiber in which an epoxy group-containing compound is previously impregnated into the fiber skeleton.

The epoxy group-containing compound is impregnated and infiltrated with 0.1 to 10.0% by mass, preferably 0.2 to 2.0% by mass, based on the fiber mass in which the water content of the aramid fiber is converted to 0%. good. Further, in order to more uniformly impregnate and permeate the epoxy group-containing compound, the epoxy group-containing compound may be diluted with water, a solvent or the like and applied. Alternatively, it may be applied together with an oil agent generally used for aramid fibers. Specific examples of the oil agent include low molecular weight fatty acid esters, polyethers, and mineral oils having 18 or less carbon atoms.

As the epoxy group-containing compound, for example, one or a mixture of two or more selected from glycidyl ether compounds of polyhydric alcohols such as glycerol, sorbitol, and polyglycerol is preferable. Specific examples thereof include glycerol diglycidyl ether, glycerol triglycidyl ether, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether. Further, since these epoxy compounds are cured, they may be used together with a known curing agent. As the curing agent, amines are preferable, and tertiary amines are particularly preferable. For example, dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, long-chain alkylpolyoxyethylene type tertiary amines obtained by adding ethylene oxide to aliphatic primary amines and the like. Can be mentioned.

The method for applying the epoxy group-containing compound to the aramid fiber is not particularly limited, and any conventionally known method may be adopted, and a dipping refueling method, a spray refueling method, a roller refueling method, and a guided refueling method using a measuring pump may be adopted. And so on.

The single yarn fineness of the organic fiber constituting the fiber-reinforced thermoplastic composite material of the present invention is not particularly limited, and is preferably 0.5 to 30 dtex, more preferably 0.5 to 10 dtex, and further preferably 1 to 1. It is in the range of 5 dtex. If it is 0.5 dtex or more, it is possible to obtain a fiber having a reinforcing effect without any difficulty in the silk reeling technique, and if it is 30 dtex or less, it is possible to uniformly disperse the short fibers in the thermoplastic material. Will be.

As the short fibers of the organic fiber, a bundle of long fibers of the organic fiber cut to a predetermined length by a known means such as a guillotine method and a rotary cutter method is used. As the long fiber bundle, a fiber bundle bundled with a sizing agent is preferably used from the viewpoint of suppressing fibrillation and cutting of short fibers during kneading with a thermoplastic material. Examples of the sizing agent include epoxy resin, polyester resin, polyurethane resin, polyether resin, vinyl ester resin, (meth) acrylate resin, polyamide resin and the like.

The number of single yarns of the fibers constituting the fiber bundle is preferably 100 to 3,000. If the number of single yarns is 100 or more, there is no risk of yarn breakage during the focusing process. Further, when the number of single yarns is 3,000 or less, the adhesiveness of the sizing agent due to the overlapping of the single yarns does not significantly deteriorate.

The amount of the sizing agent adhered is preferably 1 to 15% by mass, more preferably 2.5 to 15% by mass, based on the total weight of the fiber bundle. If the amount of the sizing agent adhered is less than 1% by mass, the effect of the sizing agent is insufficient, so that the staple fibers are easily cut in the thermoplastic material, and if it exceeds 15% by mass, it is difficult to manufacture. Accompany.

The average fiber length of the staple fibers prevents the staple fibers from being entangled with each other when kneaded with the thermoplastic material and cutting the staple fibers due to shearing, and can exhibit a good reinforcing effect, and the thermoplastic material. It is preferably 5 mm or less from the viewpoint that the dispersibility of the short fibers in the fiber is good. It is more preferably 3 mm or less, still more preferably 1 to 3 mm. The average fiber length is an average value when 100 cut long fiber bundles are randomly collected and the fiber length is measured.

By kneading the short fibers with the thermoplastic material as the base material, the fiber-reinforced thermoplastic composite material of the present invention can be prepared. When kneading the staple fibers and the thermoplastic material, it is preferable to supply the staple fibers to an extruder and knead the staple fibers with the thermoplastic material to pelletize them into pellets.

By molding the fiber-reinforced thermoplastic composite material thus obtained by a known molding method such as injection molding, extrusion molding, thermoforming, blow molding, etc., it is possible to provide a molded product having an arbitrary shape.

In preparing the fiber-reinforced thermoplastic composite material, it is preferable to add 1 to 40% by mass of short fibers with respect to the total weight of the composition, more preferably 2 to 30% by mass, and further preferably 3 to 25. It is by mass, particularly preferably 3 to 10% by mass. By blending 1% by mass or more of the short fibers, the tensile yield strength of the composite material is improved, and as a result, the effect of improving the mechanical properties of the molded product is remarkably exhibited. Further, if the staple fiber content exceeds 40% by mass, no further significant improvement effect can be obtained, the process stability at the time of pellet production is lowered, the fiber content of the pellet becomes uneven, and the quality of the molded product is stable. Sex may worsen.

The fiber-reinforced thermoplastic composite material of the present invention is characterized in that the yield strength ( _{YS) of the composite material is 1.3 times or more the yield strength (Y 0 )} of the thermoplastic material as a base material. And. In the present invention, the ratio of Y _S to Y ₀ (Y _S / Y ₀ ) is defined as the “yield strength ratio”. The yield strength ratio is more preferably 1.8 times or more, still more preferably 2.0 times or more. The higher the yield strength ratio, the more excellent the material can be with respect to load deformability.

In the present invention, the yield strength is the yield strength of the stress at the upper yield point when the stress-strain curve (SS curve) in the tensile test conforming to ISO527 has (a) the upper yield point. , (B) If the stress does not show a clear top yield point and the stress shows an increase even after yielding, the stress at 40% strain is defined as the yield strength. The reason why the yield strength is defined as described above is that the stress-strain curve may not show a clear upper yield point in the case of the thermoplastic material as the base material alone.

In the fiber-reinforced thermoplastic composite material of the present invention, a phenomenon occurs in which the stress sharply decreases with strain in the stress-strain curve when the composite material is subjected to a tensile test, and has a yield point (upper yield point). It can be a composite material that can withstand deformation under load because it does not break even after yielding and has the property that the stress increases or changes at a substantially constant value.

Further, the fiber-reinforced thermoplastic composite material of the present invention has a breaking elongation of 200% or more in a tensile test based on ISO527. By having such characteristics, it can be a composite material having excellent fatigue resistance and durability.

Further, the fiber-reinforced thermoplastic composite material of the present invention is used as a master batch, or the fiber-reinforced thermoplastic composite material is blended with the thermoplastic resin, and the fiber-reinforced heat having a short fiber content of 1 to 30% by mass is preferable. A plastic resin composition. By molding the obtained fiber-reinforced thermoplastic resin composition by a known molding method such as injection molding, extrusion molding, thermoforming, blow molding, foam molding, etc., it is possible to provide a molded product having an arbitrary shape. The content of short fibers in the fiber-reinforced thermoplastic resin composition is more preferably 2 to 30% by mass, still more preferably 3 to 25% by mass, and particularly preferably 3 to 10% by mass. If the staple fiber content is 1% by mass or more, the reinforcing function can be exhibited, and if it is 30% by mass or less, the elongation rate does not significantly deteriorate the quality of the molded product.

When the fiber-reinforced thermoplastic resin composite material is blended with the thermoplastic resin, a known mixing device such as a blender or a Henshell mixer can be used.

The thermoplastic resin is not particularly limited, but from the viewpoint of compatibility with the fiber-reinforced thermoplastic composite material, it is a thermoplastic elastomer resin, a polyolefin resin, a polyvinyl chloride resin, a polystyrene resin, an acrylic resin, a polycarbonate resin, and a polyester. Resin, ABS resin, AS resin, polyoxymethylene resin, nylon resin, polyphenylene oxide resin, polyphenylene sulfide resin, polyether sulfone resin, polyamideimide resin, polyether ether telketone resin, polyether ketone ketone resin, polyetherimide resin , At least one selected from the ionomer resin and these alloy-based resins is preferable.

Additives can be added to the fiber-reinforced thermoplastic resin composition as needed. Additives include, for example, heat stabilizers, light stabilizers, UV absorbers, antioxidants, lubricants, nucleating agents, plasticizers, anticoloring agents, matting agents, antibacterial agents, deodorants, flame retardants, and charging. Examples thereof include an inhibitor, a mold release agent, a filler, a pigment, a dye and the like, and at least one selected from these additives can be blended. The blending amount of these may be the amount usually used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. Further, in the following examples and the like, "mass%" is abbreviated as "%" unless otherwise specified. The evaluation method described in the examples is as follows.

[Moisture percentage]
According to JIS K7251, the mass of about 10 g of the sample is measured, and the mass of water in the sample is measured according to the procedure of Method B. The water content is obtained by [water mass in the sample] / [sample mass].

[MFR]
According to ISO1183, pellets of fiber-reinforced thermoplastic composite material were preheated at 200 ° C. or 230 ° C. for 1 minute using a melt indexer, and MFR at the same temperature as the preheating and a load of 2160 g was measured.

[Tensile test]
After the pellets of Examples and Comparative Examples were dried with hot air at 100 ° C. for 3 hours, a 1A type molded piece (4 mm thick) described in ISO527-2 was used using an injection molding machine (SE50DUZ manufactured by Sumitomo Heavy Industries, Ltd.). Was molded. The cylinder temperature was 200 ° C. (however, Comparative Examples 1 and 2 were 230 ° C.), and the mold temperature was 40 ° C.
Using the obtained ISO tensile test piece (4 mm thick), conforming to ISO527-1 and ISO527-2, using an Instron type tensile tester (manufactured by Shimadzu Corporation, Autograph), 23 ° C, chuck spacing. A tensile test was carried out under the conditions of 50 mm and a tensile speed of 50 mm / min, and the stress (yield strength) (unit: MPa) and yield elongation (at the time of 40% strain when no clear yield was shown) and yield elongation (at the time of 40% strain) were carried out. Unit:%), elongation at break (unit:%), elastic modulus (unit: MPa) were measured. (However, the measurement limit of elongation at break is 260%)

[Bending test]
Using the ISO tensile test piece (4 mm thick) obtained by the above method, the bending strength (unit: MPa) and the bending elastic modulus (unit: MPa) were measured at a temperature of 23 ° C. in accordance with ISO178.

[Charpy impact strength]
Using the ISO tensile test piece obtained by the above method, the notched Charpy impact strength (unit: kJ / m ² ) was measured at a temperature of 23 ° C. in accordance with ISO179-1 and ISO179-2.

[density]
Using the ISO tensile test piece obtained by the above method, the sample was allowed to stand in a constant temperature room at 23 ° C. for 24 hours, and then the density was measured by the Archimedes method according to ISO1183.

(Staple preparation example 1)
Polyparaphenylene terephthalamide (PPTA) fibers (unit fineness: 1.7 dtex, total fineness: 3,300 dtex) obtained by a known method are unwound from a bobbin, and a urethane fiber sizing agent is converted into a moisture content of 0% by weight. When 2.5% by mass was applied to the fibers and dried, the fibers were continuously cut with a cutter so as to have a target value of 3.0 mm to obtain short fibers.

(Example 1)
3 parts by mass of aramid short fibers obtained in Preparation Example 1, polyester-based thermoplastic elastomer (manufactured by Toray DuPont, "Hytrel" 4057N, melting point (DSC method): 163 ° C., Vicat softening point (JIS K7206 A method): 111 ° C) 97 parts by mass is extruded with a single-screw (30 mmφ) extruder at a cylinder temperature of 190 ° C, screw rotation speed: 100 rpm, and discharge rate: about 12 kg / hr to prepare pellets of fiber-reinforced thermoplastic resin composite material. did.

(Example 2)
Pellets were prepared in the same manner as in Example 1 except that 5 parts by mass of the aramid staple fibers obtained in Preparation Example 1 and 95 parts by mass of a polyester-based thermoplastic elastomer (“Hytrel” 4057N, manufactured by Toray DuPont) were used. did.

(Example 3)
Pellets were prepared in the same manner as in Example 1 except that 10 parts by mass of the aramid staple fibers obtained in Preparation Example 1 and 90 parts by mass of a polyester-based thermoplastic elastomer (“Hytrel” 4057N, manufactured by Toray DuPont) were used. did.

(Example 4)
Pellets were prepared in the same manner as in Example 1 except that 1 part by mass of the aramid staple fiber obtained in Preparation Example 1 and 99 parts by mass of a polyester-based thermoplastic elastomer (“Hytrel” 4057N, manufactured by Toray DuPont) were used. did.

(Comparative Example 1)
Commercially available short glass fiber (fiber length: 3 mm) 5 parts by mass, polyester-based thermoplastic elastomer (Toray DuPont, "Hytrel" 5557, melting point (DSC method): 208 ° C., Vicat softening point (JIS K7206 A method) 188 ° C.) Pellets were prepared in the same manner as in Example 1 except that 95 parts by mass was used.

(Comparative Example 2)
10 parts by mass of glass short fibers obtained in Preparation Example 2, polyester-based thermoplastic elastomer (manufactured by Toray DuPont, "Hytrel" 6347, melting point (DSC method): 215 ° C., Vicat softening point (JIS K7206 A method): 201 ° C.) Pellets were prepared in the same manner as in Example 1 except that 90 parts by mass was used.

(Control Examples 1 to 3)
Only the polyester-based thermoplastic elastomers used in Examples 1 to 4, Comparative Example 1 and Comparative Example 2 were used without staples , and the conditions were the same as those of Examples 1 and 1 and 2, respectively. A let was made.

Regarding the fiber-reinforced thermoplastic composite materials (Examples 1 to 4, Comparative Examples 1 and 2) obtained in Examples and Comparative Examples, and the thermoplastic resin as a base material (Control Examples 1 to 3), the fluidity and the machine The characteristics were evaluated.
The ratio of the yield strength of the composite material obtained in each example to the material of the control example (without staples added) was defined as the yield strength ratio.

The evaluation results are shown in Table 1. In addition, Example 3 is a reference example.

From the results shown in Table 1, the fiber-reinforced thermoplastic composite material in which the aramid short fibers were blended with the thermoplastic elastomer was superior in yield strength to the non-reinforced composite material in which the short fibers were not blended.
A fiber-reinforced thermoplastic composite material in which short glass fibers are blended with a thermoplastic elastomer needs to be blended in an increased amount in order to exhibit the same yield strength as an aramid fiber-reinforced composite material. It was inferior to the aramid fiber reinforced composite material not only in high density (high weight) but also in impact strength.

Since the fiber-reinforced thermoplastic composite material of the present invention can withstand deformation under load, it can be used as a material for tires under a high load, automobile interior parts, office supplies, daily necessities, electrical appliances, medical equipment for filling chemicals, and refrigeration. It can be widely used as a material for containers and the like.

Claims (9)

Aramid staples (excluding pulp),
It is composed of a polyester-based thermoplastic elastomer having a breaking elongation (ISO527 compliant) of 200% or more in a tensile test.
The stress-strain curve (SS curve) in the tensile test conforming to ISO527 is
(A) If there is an upper yield point, the stress at the upper yield point,
(B) If the stress does not show a clear upper yield point and the stress increases even after yielding, the stress at 40% strain,
When the yield strength is
The fiber reinforcement is characterized in that the yield strength is 1.3 times or more the yield strength (ISO527 compliant) of the polyester-based thermoplastic elastomer as the base material, and the tensile elongation at break is 200% or more. Thermoplastic composite material.
The fiber-reinforced thermoplastic composite material according to claim 1, wherein the tensile yield strength in the tensile test conforming to ISO527 is 10 MPa or more. The fiber-reinforced thermoplastic composite material according to claim 1 or 2, wherein the content of the short fiber in the fiber-reinforced thermoplastic composite material is 1 to 40% by mass. The fiber-reinforced thermoplastic composite material according to any one of claims 1 to 3 , wherein the aramid fiber is a polyparaphenylene terephthalamide fiber in which an epoxy group-containing compound is impregnated in a fiber skeleton. The fiber-reinforced thermoplastic composite material according to any one of claims 1 to 4 , wherein the average fiber length of the short fibers is 5 mm or less. A molded product obtained by molding the fiber-reinforced thermoplastic composite material according to any one of claims 1 to 5 . A fiber-reinforced thermoplastic resin composition having a short fiber content of 1 to 30% by mass, wherein the fiber-reinforced thermoplastic composite material according to any one of claims 1 to 5 is blended with the thermoplastic resin. The thermoplastic resin is thermoplastic elastomer resin, polyolefin resin, polyvinyl chloride resin, polystyrene resin, acrylic resin, polycarbonate resin, polyester resin, ABS resin, AS resin, polyoxymethylene resin, nylon resin, polyphenylene oxide resin, polyphenylene. Claim 7 which is at least one selected from a sulphide resin, a polyether sulfone resin, a polyamideimide resin, a polyether ether telketone resin, a polyether ketone ketone resin, a polyetherimide resin, an ionomer resin, and an alloy resin thereof. The fiber-reinforced thermoplastic resin composition according to. Further containing an additive, the additive is a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antioxidant, a lubricant, a nucleating agent, a plasticizing agent, an antioxidant, a matting agent, an antibacterial agent, a deodorant, The fiber-reinforced thermoplastic resin composition according to claim 7 or 8 , which is at least one selected from flame retardant, antistatic agent, mold release agent, filler, pigment and dye.