JP6775875B2 - Fiber reinforced plastics and fiber reinforced molded products - Google Patents

Description

The present invention relates to an aramid fiber reinforcing material suitable for reinforcing a thermoplastic resin, and a fiber reinforced molded product using the aramid fiber reinforcing material.

Conventionally, as a means for improving the mechanical strength of a thermoplastic resin, it has been known to blend reinforcing fibers such as glass fiber, carbon fiber, and aramid fiber, and generally, short fibers such as chopped strand and heat are used. A thermoplastic resin is mixed, the mixed resin is extruded by an extruder to pelletize it, and this is injection-molded to produce a fiber-reinforced thermoplastic resin.

However, the fact is that it is difficult to obtain the desired performance because the reinforcing effect of the reinforcing fiber is not sufficient, and especially when the affinity between the reinforcing fiber and the thermoplastic resin is inferior, the reinforcing fiber is used for reinforcement in the molded product. Since the fibers are difficult to disperse uniformly, it is difficult to obtain the desired performance.

In order to solve such a problem, a method (Patent Document 1) has been proposed in which a urethane-based binder is attached to the reinforcing aramid fiber yarn to improve the adhesiveness between the reinforcing aramid fiber and the thermoplastic resin. However, even if the treatment described in Patent Document 1 is applied, in the case of aramid fiber, the rigidity is smaller than that of glass fiber or carbon fiber, so that the orientation of the fiber in the molded product is poor, and the molded product There is a problem that the effect of improving the mechanical properties of Aramid is smaller than that of glass fiber or the like.

A fiber reinforcing material composed of strand-shaped pellets in which the roving of the aramid fiber is drawn out and the periphery of the aramid fiber is coated with a thermoplastic resin to enhance the affinity with the thermoplastic resin is also known (for example, Patent Document). 2-3). A thermoplastic resin composition containing a fiber reinforcing material composed of strand-shaped pellets of aramid fibers surface-treated with a curable epoxy compound is more tensile than a composition containing a fiber-reinforced material not subjected to surface treatment. Although mechanical properties such as strength and bending strength are improved, the treatment agent is merely physically adsorbed on the surface of the aramid fiber, and the interaction between the fiber and the treatment agent is insufficient. Further improvement of mechanical properties is required by increasing the interaction between the fiber and the treatment agent.

Japanese Unexamined Patent Publication No. 2004-091540 Japanese Unexamined Patent Publication No. 2008-274138 Japanese Unexamined Patent Publication No. 2013-12976

An object of the present invention is an aramid fiber reinforcing material that can achieve further improvement in mechanical stability by using it in a thermoplastic resin molded product as a reinforcing fiber, and a machine using the aramid fiber reinforcing material. The purpose is to provide a molded product having excellent characteristics.

As a result of diligent studies to solve the above problems, the present inventors have made thermoplasticity between the fibers of the aramid fiber bundle composed of the polyparaphenylene terephthalamide fiber composite in which the curable epoxy compound is impregnated into the fiber skeleton. The aramid fiber reinforcing material obtained by melting and impregnating the resin has a high degree of orientation of the aramid fiber in the molded product, and the molded product using the fiber reinforcing material has a remarkable effect of improving mechanical properties. We found that and arrived at the present invention.

That is, in the present invention, an aramid long fiber bundle composed of a polyparaphenylene terephthalamide fiber composite in which a curable epoxy compound (however, not containing a curing agent) is impregnated in an amount of 0.1 to 10% by mass in the fiber skeleton . Provided is an aramid fiber reinforcing material characterized in that the fibers are impregnated with a thermoplastic resin.

Further, the present invention is characterized in that the above-mentioned aramid fiber reinforcing material is cut and the value of the cutting length (μm) / fiber diameter (μm) of the aramid fiber is in the range of 100 to 500. Provides fiber reinforcement.

Further, the present invention provides a molded product characterized in that the above-mentioned aramid fiber reinforcing material and a thermoplastic resin are mixed or injection molded by the aramid fiber reinforcing material alone.

Since the aramid fiber reinforcing material of the present invention uses an aramid fiber bundle composed of a polyparaphenylene terephthalamide fiber composite in which a curable epoxy compound is impregnated into the fiber skeleton, it has excellent impregnation property with a thermoplastic resin. Not only that, but also the orientation of the aramid fiber in the molded product is excellent, so that it is possible to provide a molded product having improved mechanical properties as compared with the conventional case.

The polyparaphenylene terephthalamide (PPTA) in the present invention is a polymer obtained by polycondensing terephthalic acid and paraphenylene diamine, but a polymer obtained by copolymerizing a small amount of dicarboxylic acid and diamine can also be used. Alternatively, the molecular weight of the copolymer is usually preferably 20,000 to 25,000.

In ordinary PPTA fibers, PPTA is dissolved in concentrated sulfuric acid, the viscous solution is extruded from a spun spout, spun into air or water to form filaments, and then neutralized with an aqueous sodium hydroxide solution. Finally, it is obtained by drying and heat treatment at 120 to 500 ° C.
The polyparaphenylene terephthalamide fiber composite (hereinafter, may be abbreviated as "PPTA fiber composite") in which a curable epoxy compound is impregnated into the fiber skeleton of the present invention has a water content of 15 to 200 mass. It can be preferably obtained by impregnating the curable epoxy compound into the PPTA fiber skeleton adjusted to%.

The PPTA fiber adjusted to have a water content of 15 to 200% by mass can be obtained, for example, as follows. That is, PPTA is dissolved in concentrated sulfuric acid to obtain a viscous solution of 18 to 20% by mass, which is discharged from the spinneret, spun into the air for a short time, and then spun into water (at this time, the spinneret). The shear rate at the time of discharge is preferably 25,000 to 50,000 sec ^-1 ), and after undergoing a water-washing neutralization treatment, the obtained raw yarn is dried at 100 to 160 ° C., preferably for 5 to 20 seconds. To do. If the water content is less than 15% by mass, it becomes difficult to uniformly permeate the resin dispersion into the fiber skeleton, while if the water content exceeds 200% by mass, the permeated resin dispersion is taken up by the winding process. When it comes into contact with a guide or the like, it may fall off together with moisture, and the fiber winding process becomes difficult. The water content of the PPTA fiber is preferably 15 to 100% by mass, more preferably 20 to 100% by mass, from the viewpoints of the permeability of the curable epoxy compound into the PPTA fiber skeleton, the ease of adjusting the water content of the PPTA fiber, the production efficiency, and the like. It is 50% by mass, particularly preferably 30 to 50% by mass.

Further, the PPTA fiber composite is kept in a state where the crystal size of the PPTA fiber is less than 50 angstrom and the water content is maintained in a state of 15 to 200% by mass while changing the heat treatment conditions at a temperature of 100 to 160 ° C. It can be preferably obtained by preparing a suitable PPTA fiber and infiltrating the curable epoxy compound into the PPTA fiber skeleton.

It is desirable that the PPTA fiber impregnated with the curable epoxy compound has no history of being dried to a moisture content of less than 15% by mass after spinning. By using PPTA fiber whose water content is always adjusted to 15% by mass or more, it is possible to maintain a state in which the curable epoxy compound easily permeates.

When the curable epoxy compound is permeated into the PPTA fiber skeleton adjusted to have a water content of 15 to 200% by mass, the curable epoxy compound can be dissolved in a solvent or the like and permeated. Further, when a fiber oil agent is applied, it may be contained in the oil agent and permeated, or may be used in a separate process from the oil agent. Examples of the oil agent include general oil agents used for PPTA fibers, for example, low molecular weight fatty acid esters, polyethers, mineral oils and the like having 18 or less carbon atoms. When the curable epoxy compound is contained in an oil agent, a solvent or the like and permeated, it is preferably contained in the oil agent or the solvent in an amount of about 20 to 60% by mass, more preferably 30 to 50% by mass. The curable epoxy compound is preferably impregnated in a solvent or an oil agent because it can be easily permeated into the PPTA fiber skeleton.

The components to be permeated into the PPTA fiber skeleton include penetrants such as nonionic surfactants, silicone compounds, fluorine compounds, organic surfactants and the like as other components as long as the effects of the present invention are not impaired. A smoothing agent, a silane-based or isocyanate-based coupling agent, or the like may be contained.

The method of applying the curable epoxy compound to the PPTA fiber is not particularly limited, and any conventionally known method may be adopted, for example, a dipping lubrication method, a spray lubrication method, a roller lubrication method, a guide using a measuring pump. Methods such as the refueling method can be mentioned.

A PPTA fiber composite having a water content of 15 to 200% by mass impregnated with a curable epoxy compound was prepared, and then dried and heat-treated to remove water, and the water content was reduced to less than 15% by mass, more preferably 10% by mass. When it is less than, a PPTA fiber composite can be obtained. The drying / heat treatment conditions are not particularly limited, and for example, it is preferably performed at 80 to 300 ° C., preferably 100 to 250 ° C. By heat treatment, the crystal size of PPTA is increased and the intercrystal gap is narrowed, so that the curable epoxy compound can be fixed in the PPTA fiber skeleton.

The curable epoxy compound is preferably permeated in an amount of 0.1 to 10.0% by mass, more preferably 0.2 to 5.0% by mass, based on the fiber mass in which the water content of the PPTA fiber is converted to 0%. .. If the amount of permeation is small, the effect of improving the affinity with the thermoplastic resin may be insufficient.

As the curable epoxy compound, one kind selected from an aliphatic epoxy compound or an epoxy compound having an aromatic ring, or two or more kinds can be used in combination. Further, it is desirable that the curable epoxy compound is appropriately selected according to the type of the thermoplastic resin.

Aliphatic epoxy compounds include glycidyl ether compounds of polyhydric alcohols such as glycerol, diglycerol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, neopentyl glycol, sorbitol, and polyglycerol. One or a mixture of two or more selected from the above is preferable.

For example, glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether. , Neopentyl glycol diglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether and the like.
Among these aliphatic epoxy compounds, glycerol diglycidyl ether, glycerol triglycidyl ether, and sorbitol polyglycidyl ether are particularly preferable.

As the epoxy compound having an aromatic ring, one kind or a mixture of two or more kinds selected from epoxy compounds having a bisphenol skeleton is preferable. For example, bis (4-hydroxyphenyl) methane [bisphenol F], 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (3-methyl-4-hydroxyphenyl) propane [bisphenol] Examples thereof include glycidyl etherified products such as C]. Among these, glycidyl ether compounds of bisphenol A and bisphenol F, which are liquid at room temperature, are particularly preferable.

Even without a curing agent, the curing reaction of the curable epoxy compound proceeds .

When the curable epoxy compound is permeated into the PPTA fiber skeleton, it may be diluted with a general solvent and used, or a permeation aid may be further mixed and used in the solvent. Examples of the penetrating aid include compounds represented by the general formula (I), which may be used alone or in combination of two or more as appropriate. When a penetrating aid is mixed with the curable epoxy compound, it is preferable to use the curable epoxy compound and the penetrating aid in a ratio of 2: 8 to 8: 2 (mass ratio).

In the above general formula (I), R ¹ is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 1 to 10 carbon atoms, preferably an alkyl group having 4 to 8 carbon atoms or 4 to 10 carbon atoms. It is an alkenyl group of 8, and R ² represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkenyl group having 1 to 5 carbon atoms. R ² is preferably a hydrogen atom.
In the general formula (I), A represents an alkylene group having 2 to 4 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms, n represents an average addition mol of oxyalkylene group (AO) It is an integer of 1 to 10 representing a number, preferably 2 to 8. In − (AO) −, a single oxyalkylene group may be added, or two or more kinds of oxyalkylene groups may be added.

Specific examples of the compound include diethylene glycol monobutyl ether, diethylene glycol mono2-ethylhexyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, polypropylene glycol (n = 3) glyceryl ether and the like. The penetrating aid is preferably a compound having excellent compatibility with water and a curable epoxy compound.

The fiber diameter of the PPTA fiber composite impregnated with the curable epoxy compound forming the aramid fiber bundle is preferably 10 μm to 30 μm, more preferably 18 μm to 30 μm. The aramid fiber bundle (one fiber bundle) preferably contains a PPTA fiber composite in which 100 to 6,000 curable epoxy compounds are impregnated, and more preferably 1,000 to 5,000 fibers. Is. When the fiber diameter of the PPTA fiber composite is 14 μm or less, the orientation of the PPTA fibers tends to be randomized, and when the fiber diameter is less than 10 μm, it may not be able to exert a sufficient function as a fiber reinforcing material. Further, when the fiber diameter of the PPTA fiber composite exceeds 30 μm, the occupied surface area of the PPTA fiber is reduced and the adhesive surface with the thermoplastic resin is reduced, so that the tensile strength, tensile elastic modulus, and bending strength of the molded product are reduced. , The flexural modulus tends to decrease.

The aramid fiber reinforcing material of the present invention is preferably produced by a pultrusion molding method. The pultrusion method is a method in which a fiber roving composed of thousands to tens of thousands of filaments is opened and pulled out, impregnated with a resin, and cut to a desired length to form a strand-shaped pellet. ..
That is, the opened aramid fiber bundle is passed through the crosshead die or offset die to which the extruder is attached, and the molten thermoplastic resin is sent from the extruder to be impregnated between the fibers of the aramid fiber bundle. The aramid fiber bundle impregnated with the thermoplastic resin is squeezed by a die or the like at the die outlet to remove excess resin and is cooled to maintain the orientation of the aramid fiber.
In the present invention, since the curable epoxy compound is pre-impregnated into the PPTA fiber composite forming the aramid fiber bundle, the thermoplastic resin is more uniformly impregnated between the fibers while maintaining the orientation of the PPTA fibers. Can be made to.

The content of the PPTA fiber composite infiltrated with the curable epoxy compound in the aramid fiber reinforcing material can be adjusted by appropriately setting the melting temperature of the thermoplastic resin (that is, the fluidity of the resin), but it is preferable. Is 10 to 80% by mass, more preferably 10 to 40% by mass. If the content of the PPTA fiber composite in the fiber reinforcing material exceeds 80% by mass, the impregnation of the thermoplastic resin tends to be insufficient, and the dispersibility of the PPTA fiber composite during injection molding after mixing with the matrix resin. Is not preferable because it is inferior. Further, if the content of the PPTA fiber composite in the fiber reinforcing material is less than 10% by mass, sufficient mechanical properties cannot be imparted to the molded product, which is not preferable in terms of practical use.

Examples of the thermoplastic resin to be impregnated in the aramid fiber bundle include polyolefin resins such as polyethylene resin, polypropylene resin and polybutylene resin; methacrylic resins such as polymethylmethacrylate resin; and polystyrene resins such as polystyrene resin, ABS resin and AS resin; Polyester resin such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene terephthalate resin, polyethylene naphthalate (PEN) resin, poly 1,4-cyclohexyldimethylene terephthalate (PCT) resin; polyamide-based Resin; Polyvinyl chloride resin; Polyoxymethylene (POM) resin; Polycarbonate (PC) resin; Polyphenylene sulfide (PPS) resin; Modified polyphenylene ether (PPE) resin; Polyetherimide (PEI) resin; Polysulfone (PSF) resin; Polyethersulfone (PES) resin; Polycarbonate resin; Polyethernitrile (PEN) resin; Polyetherketone (PEK) resin; Polyetheretherketone (PEEK) resin; Polyetherketoneketone (PEKK) resin; Polyetherketone (PI) resin Polycarbonateimide (PAI) resins; or modified resins of these resins can be mentioned. These thermoplastic resins can be used alone or in combination of two or more. An unmodified resin and a modified resin can be mixed and used.

Examples of the above-mentioned polyamide resin include a polyamide resin formed from diamine and dicarboxylic acid and a copolymer thereof, specifically, a polycaproamide (nylon 6) resin and a polyhexamethylene adipamide (nylon 66). Resin, polyhexamethylene sebacamide (nylon 610) resin, polyhexamethylene dodecamide (nylon 612) resin, polydodecaneamide (nylon 12) resin, polyhexamethylene terephthalamide (nylon 6T) resin, polyhexanemethylene iso Phtalamide (nylon 6I) resin, polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T) resin, polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T) resin, polyhexamethylene Nylon resins such as adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I) resin and nylon copolymer resins can be mentioned.

The cooled fiber reinforced material is cut to a desired length by a cutter such as a pelletizer to become a fiber reinforced material for blending a thermoplastic resin.

When the fiber reinforcing material is cut, the cutting length is preferably in the range of 1 mm to 15 mm, and if the cutting length is less than 1 mm, it is difficult to improve the mechanical properties of the molded product. Further, if the cutting length exceeds 15 mm, it becomes difficult to uniformly mix with the matrix resin, so that the dispersibility of the aramid fiber in the molded product tends to be inferior. The average diameter of the fiber reinforcing material is preferably about 0.1 mm to 3 mm.

In the fiber reinforced material produced by the pultrusion method, the cutting length of the fiber reinforced material and the fiber length of the fibers contained in the fiber reinforced material are substantially equal. Therefore, by shortening the cutting length of the fiber reinforced material, the aspect ratio (length / thickness) of the aramid fiber becomes smaller, and the apparent flexural modulus improves, which makes it difficult for the aramid fiber to bend and improves the orientation. It is expected that the tensile strength, tensile elastic modulus, bending strength, and flexural modulus of the molded product will be improved. On the other hand, if the aramid fiber is made thicker, the occupied surface area per fiber mass decreases, and there is a concern that the physical properties of the molded product may deteriorate due to the decrease in the interface with the matrix resin. From this point of view, the cutting length of the fiber reinforcing material is preferably in the range of 100 to 500 in the value of the cutting length (μm) / the fiber diameter (μm) of the aramid fiber.

The cut aramid fiber reinforcing material is dry-blended with the matrix resin or is not blended as it is and is injection-molded to obtain a molded product. The PPTA fiber composite content in the molded product is preferably selected in the range of 5 to 60% by mass.

The above matrix resin may be the same as or different from the thermoplastic resin used for impregnating the aramid fiber bundle, but if they are different, it is desirable to select a resin compatible with each other.

Thermoplastic resins and / or matrix resins used to impregnate aramid fiber bundles are conventional additives such as lubricants, plasticizers or softeners, colorants, dispersants, mold release agents, stabilizers, antioxidants, etc. An ultraviolet absorber, an antistatic agent, a flame retardant, an antiblocking agent, a filler and the like may be contained in a general ratio. These additives can be used alone or in combination of two or more.

The flow state when injection molding is performed by mixing the cut fiber reinforced plastic pellets alone or with a matrix resin is a general fountain flow, in which a skin layer is formed on the mold surface side and a core layer is formed on the inside, and molding is performed. The cross section of the product forms a three-layer structure of skin / core / skin layer, the fibers of the skin layer tend to be oriented in the flow direction, and the fibers of the core layer tend to be oriented in the direction orthogonal to the flow direction. Therefore, when the orientation of the PPTA fiber composite is increased, the reinforcing effect of the matrix resin is improved, and a molded product having excellent mechanical properties can be obtained.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, each measured value in an Example followed the following method.

(1) Moisture content (mass%)
The mass of about 5 g of the sample is measured, treated at 105 ° C. for 4 hours, left at 24 ° C. and 55% RH for 5 minutes, and then the mass is measured again. The moisture content used here is the dry base moisture content obtained by { [mass before drying-mass after drying] / [mass after drying] } x 100.

(2) Tensile test and bending test A test piece was cut out from the molded product, the tensile property was evaluated according to the ISO527-1 and 2 methods, and the bending property was evaluated according to the ISO178 method. The test piece was prepared by injection molding. The number of measurements was n = 5 in each direction, and the average value of all the measurement results was calculated.

(Example 1)
1 kg of PPTA (molecular weight of about 20,000) obtained by a usual method is dissolved in 4 kg of concentrated sulfuric acid, and discharged from a mouthpiece having 1,500 holes with a diameter of 0.1 mm so as to have a shear rate of 30,000 sec ^-1. Then, after spinning in water at 4 ° C., neutralization treatment was performed with a 10% by mass aqueous sodium hydroxide solution under the conditions of 10 ° C. × 15 seconds, and then low-temperature drying at 110 ° C. × 15 seconds was performed to obtain a moisture content. Prepared to be 35% untreated PPTA fiber.
The PPTA fiber is passed through a dip bath containing triglycerol triglycidyl ether as a curable epoxy compound and a penetrating aid (mass ratio 1/1), squeezed with a roll, the amount of adhesion is adjusted, and dried at 105 ° C. for 4 hours. As a result, a PPTA fiber composite was produced in which a curable epoxy compound and a penetrating aid were impregnated in an amount of 2% by mass with respect to the mass of the PPTA fiber when the water content was converted to 0% by mass.

An aramid fiber reinforcing material was produced using the above PPTA fiber composite (fiber diameter; 20 μm). In the impregnation die, an aramid fiber bundle consisting of 1,500 PPTA fiber composites is impregnated with a polypropylene resin melted at a temperature of 250 ° C., and then cut into a length of 7 mm with a pelletizer to have an aramid fiber content of 30 mass. % Pellet-like (cylindrical) fiber reinforced material was obtained.
The obtained pellets were injection molded by an injection molding machine at a temperature of 230 ° C. to obtain a molded product. The tensile characteristics and bending characteristics of the obtained molded product were measured.

(Example 2)
1 kg of PPTA (molecular weight of about 20,000) obtained by a usual method is dissolved in 4 kg of concentrated sulfuric acid, and discharged from a mouthpiece having 1,500 holes with a diameter of 0.1 mm so as to have a shear rate of 30,000 sec ^-1. Then, after spinning in water at 4 ° C., neutralization treatment was performed with a 10% by mass aqueous sodium hydroxide solution under the conditions of 10 ° C. × 15 seconds, and then low-temperature drying at 110 ° C. × 15 seconds was performed to obtain a moisture content. Prepared to be 35% untreated PPTA fiber.
The PPTA fiber is passed through a dip bath containing triglycerol triglycidyl ether as a curable epoxy compound and a penetrating aid (mass ratio 1/1), squeezed with a roll, the amount of adhesion is adjusted, and dried at 105 ° C. for 4 hours. As a result, a PPTA fiber composite was produced in which a curable epoxy compound and a penetrating aid were impregnated in an amount of 2% by mass with respect to the mass of the PPTA fiber when the water content was converted to 0% by mass.

An aramid fiber reinforcing material was produced using the above PPTA fiber composite (fiber diameter; 12 μm). In the impregnation die, an aramid fiber bundle consisting of 1,500 PPTA fiber composites is impregnated with a polypropylene resin melted at a temperature of 250 ° C., and then cut into a length of 7 mm with a pelletizer to have an aramid fiber content of 30 mass. % Pellet-like (cylindrical) fiber reinforced material was obtained.
The obtained pellets were injection molded by an injection molding machine at a temperature of 230 ° C. to obtain a molded product. The tensile characteristics and bending characteristics of the obtained molded product were measured.

(Comparative Examples 1-2)
Fiber diameter 20 [mu] m and polyparaphenylene terephthalamide fiber diameter 12μ m (PPTA) fibers using the (Kevlar (R)) was prepared aramid fiber reinforcement. In the impregnation die, an aramid fiber bundle consisting of 1,500 polyparaphenylene terephthalamide fibers was impregnated with a polypropylene resin melted at a temperature of 250 ° C., and then cut into a length of 7 mm with a pelletizer to obtain an aramid fiber content. A pellet-shaped (cylindrical) fiber reinforcing material of 30% by mass was obtained.
The obtained pellets were injection molded by an injection molding machine at a temperature of 230 ° C. to obtain a molded product. The tensile characteristics and bending characteristics of the obtained molded product were measured.

Table 1 shows the results of evaluating the tensile properties and bending properties of the molded products obtained in Examples and Comparative Examples by the above method.

From the results in Table 1, it was possible to obtain a PP molded product with improved tensile strength and bending strength by using the fiber reinforced material of the present invention.

Comparing the aramid fiber bundle with a fiber diameter of 20 μm and the aramid fiber bundle with a fiber diameter of 12 μm, the aramid fiber having a large fiber diameter has a smaller total fiber surface area than the aramid fiber having a smaller fiber diameter, but the machine of the molded product. There was almost no adverse effect on the characteristics, and the results were equal to or better than those of aramid fibers having a small fiber diameter.

The fiber reinforced material of the present invention is required to have excellent heat resistance and mechanical properties by being processed by a known processing method, such as automobile structural materials and various parts, electronic device housings and various parts, and precision machinery. It can be used for various purposes such as parts, and its practical value is great.

Claims (8)

Heat is generated between the fibers of the aramid long fiber bundle composed of the polyparaphenylene terephthalamide fiber composite in which 0.1 to 10% by mass of a curable epoxy compound (but does not contain a curing agent) is impregnated into the fiber skeleton . An aramid fiber reinforcing material characterized by being impregnated with a plastic resin. The aramid fiber reinforcing material according to claim 1, wherein the polyparaphenylene terephthalamide fiber composite has a fiber diameter of 10 μm to 30 μm. Curable epoxy compounds are glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, penta. The aramid fiber reinforcing material according to claim 1 or 2, which is one kind selected from erythritol polyglycidyl ether, neopentyl glycol diglycidyl ether, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether, or a mixture of two or more kinds. The aramid fiber reinforcing material according to claim 1 or 2, wherein the curable epoxy compound is an epoxy compound having a bisphenol skeleton. The aramid fiber reinforcing material according to any one of claims 1 to 4, which is a polyparaphenylene terephthalamide fiber composite in which a curable epoxy compound and a penetrating aid are further impregnated. The aramid fiber reinforcing material according to claim 5, wherein the permeation aid is a compound represented by the following general formula (I).

(In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 carbon atom. . shows the 5 alkenyl group also, a is an alkylene group having 2 to 4 carbon atoms, n is an integer from 1 to 10 representing the average number of moles added of the oxyalkylene group (AO) Incidentally,. - In (AO)-, a single oxyalkylene group may be added, or two or more types of oxyalkylene groups may be added.) The aramid fiber reinforcing material according to any one of claims 1 to 6 is cut, and the value of the cut length (μm) / fiber diameter (μm) of the aramid fiber is in the range of 100 to 500. Aramid fiber reinforcement material. A molded product obtained by mixing the aramid fiber reinforcing material according to claim 7 with a thermoplastic resin, or injection molding the aramid fiber reinforcing material alone.