JP2008095066A - Molded article from fiber-reinforced thermoplastic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded article from a fiber-reinforced thermoplastic resin which contains a reinforcing fiber having a specified flat section and a fiber length distribution shifted to a long-fiber side and which are excellent in mechanical strengths, heat resistance, warping properties, and surface appearance. <P>SOLUTION: The molded article from a thermoplastic resin is made from a thermoplastic resin composition comprising: (A) 70 to 35 wt.% of a thermoplastic resin; and (B) 30 to 65 wt.% of a reinforcing fiber whose section is a flat shape having a flatness of 2.3 or above as defined by the following formula: flatness = the major axis (a) of a reinforcing fiber/the minor axis (b) thereof, and is characterized in that the weight-average fiber length of the reinforcing fiber in the molded articles is 1 mm or above. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fiber-reinforced thermoplastic resin molded article, and more specifically, includes a reinforcing fiber having a flat cross-sectional shape, the fiber length distribution of the reinforcing fiber is shifted to the long fiber side, mechanical strength, heat resistance The present invention relates to a fiber reinforced thermoplastic resin molded article having excellent properties, warpage, and surface appearance.

  Thermoplastic resin molded products containing reinforcing fibers such as glass fibers and carbon fibers are excellent in mechanical strength, heat resistance, chemical resistance, etc., and are used in parts such as the automotive field, electrical and electronic equipment field, and precision machine field. It is used as. However, with the recent demand for weight reduction of parts, parts are becoming smaller and thinner, and mechanical strength and dimensional accuracy are required more severely. The development of materials suitable for such required characteristics has been demanded. In particular, in the automotive field, it is required to have sufficient mechanical strength even at a high temperature of 100 ° C. or higher for use as a component in an engine room. Resin products are also being used in supporting structures.

With respect to the reinforcing fiber length in a molded article, it has been conventionally known that mechanical strength such as rigidity and impact resistance is improved by increasing the fiber length. For example, Patent Document 1 discloses that (A) a polyamide resin, (B) a fibrous reinforcing material having a length of 3 mm or more, 5 to 80% by weight (in the composition), and (C) a fatty acid metal salt having 22 to 32 carbon atoms. Are blended in an amount of 0.01 to 3% by weight (in the composition), a long fiber reinforced polyamide resin composition having excellent mechanical strength and moldability, and a molded product obtained by injection molding the resin composition. It is disclosed. Moreover, in patent document 2, the (A) polyamide resin in patent document 1 is a blend of nylon 66 component / nylon 6 component = 99-1 wt% / 1-99 wt%, good surface appearance, high heat deformation temperature And a molded product formed by injection molding the resin composition.
However, the fibrous reinforcing material used in the resin compositions described in Patent Documents 1 and 2 has a circular cross section for ease of manufacture, and the fibrous reinforcing material having such a cross-sectional shape was used. In this case, although the mechanical strength is improved, the fibrous reinforcing material is crushed during the injection molding, the fiber length of the reinforcing material remaining in the molded product is shortened, and the reinforcing effect by the reinforcing material is reduced. Due to the orientation of the reinforcing material, there is a problem that the molded product has directionality and warpage occurs, and only specific parts are applied. Patent Document 2 stipulates that the fiber length of the fibrous reinforcing material dispersed in the injection-molded product is 1 mm or more in terms of the weight average fiber length. In addition, there is no description regarding the fiber length in the actual molded product.

Patent Document 3 is an invention that approximates the relationship between the shape of fiber length distribution in a resin molded product containing a long fiber reinforcing material and the moldability and physical properties of the molded product by a two-fraction Weibull distribution. It is described that the balance between formability and physical properties of the molded product is excellent when the shape is such that the tail is gently pulled from the shorter one to the longer one. In Patent Document 4, as a long fiber reinforced thermoplastic resin exterior molded body in which the anisotropy of the molded body caused by fiber orientation during injection molding is reduced, the content of reinforcing fibers dispersed in the molded body is 30% by weight. 90% by weight, the weight average fiber length is 1.5 mm to 10 mm, the maximum projected area of the compact is 20000 mm ² or more, and the channel length of the narrow channel having a cross-sectional area of 100 mm ² or less at the time of molding is The maximum linear expansion coefficient of a molded body part having a thickness of 150 mm or less and a thickness of 2 mm or more is 5 × 10 ⁻⁵ K ⁻¹ or less, and the ratio of the maximum linear expansion coefficient / minimum linear expansion coefficient is 1.8. A long fiber reinforced thermoplastic resin exterior molded body is disclosed as follows. However, the reinforcing material used in the technology is also of a normal circular cross-sectional shape, moldability and impact strength when the fiber length is long, appearance of the actual molded product, dimensional stability due to molding shrinkage and warpage, etc. That's not enough.

  In order to solve such a problem, in Patent Document 5, by making the cross-sectional shape of the glass fiber, which is representative of the reinforcing fiber, flat, the specific surface area is increased compared to the glass fiber having a circular cross section, and the matrix resin composition By increasing the fiber length in the molded body (average fiber length is 0.47 mm for a circular cross-sectional shape and 0.57 mm for an eyebrows cross-sectional shape) It has been shown that the mechanical strength improves. However, although the resin composition described in Patent Document 5 is effective in improving tensile strength and surface smoothness and preventing warpage, it is not sufficient as compared with a resin composition containing a circular cross-section glass fiber, but is not sufficient in impact strength. In particular, when a polyamide resin is used as the thermoplastic resin, it may be reduced to the same extent as when a glass fiber having a circular cross section is used.

  Patent Document 6 discloses a method of making flat glass fibers into long fibers in order to solve the problems listed in Patent Document 5. Specifically, a flat glass fiber filament having a flat cross section is formed in a pellet made of a thermoplastic resin, and a plurality of filaments are arranged in one direction so that both end faces of the filament reach the surface of the pellet. Providing glass fiber-containing pellets is described. However, Patent Document 6 describes the remaining fiber length in the molded article, but does not mention any explanation of the overall fiber length distribution or the correlation between the fiber length distribution and the physical properties of the molded article. In addition, when the technique is used, the remaining fiber length of the glass fiber in the molded product is not sufficiently long (in the example, 0.49 mm is long), and thus such a molded product has improved impact strength to some extent. However, in the recent trend where higher performance is required, it cannot be said that the problems of mechanical strength reduction, strength maintenance under high-temperature atmosphere, and dimensional change due to resin shrinkage and warpage have not been sufficiently solved.

JP-A-5-9380 JP-A-6-107944 Japanese Patent Laid-Open No. 9-286036 JP 2006-82275 A Japanese Patent Publication No. 2-60494 JP 2006-45390 A

  The present invention has been made in view of the above situation, and its purpose is to provide a fiber-reinforced thermoplastic resin molded article excellent in dimensional accuracy such as mechanical strength, heat resistance, warpage, and surface appearance. is there.

  As a result of intensive studies to solve the above problems, the present inventors have used a reinforcing fiber having a flat cross-sectional shape of the reinforcing fiber, and at the same time, keeping the fiber length of the reinforcing fiber remaining in the molded product long. Specifically, it has been found that by setting the weight average fiber length of the reinforcing fibers to 1 mm or more, not only the mechanical strength is improved, but also surprisingly, the heat resistance, dimensional accuracy, and surface appearance are improved at the same time. The present invention has been reached.

That is, the gist of the present invention is as follows. (A) 70 to 35% by weight of thermoplastic resin, (B) Reinforcing fiber having a flat shape with a flatness of 2.3 or more according to the following formula (hereinafter referred to as “flat reinforcing fiber”) ) In a molded article made of a thermoplastic resin composition containing 30 to 65% by weight, the fiber-reinforced thermoplastic resin molded article is characterized in that the weight average fiber length of reinforcing fibers in the molded article is 1 mm or more.
Specifically, it was achieved by the following means.
(1) (A) 70 to 35% by weight of a thermoplastic resin, (B) a thermoplastic resin composition containing 30 to 65% by weight of reinforcing fibers having a flat shape with a cross-section of 2.3 or more according to the following formula: In a molded article, a fiber-reinforced thermoplastic resin molded article, wherein the weight average fiber length of reinforcing fibers in the molded article is 1 mm or more.
Flatness ratio = reinforcing fiber long diameter (a) / reinforcing fiber short diameter (b)
(2) The fiber-reinforced thermoplastic resin molded article according to (1), wherein the flatness of the (B) reinforcing fiber is 2.3 to 5.
(3) The fiber-reinforced thermoplastic resin molded article according to (1) or (2), wherein the weight average fiber length is 1 to 10 mm.
(4) The fiber-reinforced thermoplastic resin molding according to any one of (1) to (3), wherein the proportion of reinforcing fibers having a fiber length of 1 mm or more in the molded product is 30% by weight or more in all reinforcing fibers. Goods.
(5) The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (4), wherein the cross-sectional shape of the (B) reinforcing fiber is an oval.
(6) The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (5), which contains at least one polyamide resin as the thermoplastic resin (A).
(7) The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (5), which contains at least one polyester resin as the (A) thermoplastic resin.
(8) (A) The thermoplastic resin is at least a mixed diamine composed of 0 to 50 mol% paraxylylenediamine and 50 to 100 mol% metaxylylenediamine, an α having 6 to 12 carbon atoms, The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (5), including a polyamide resin obtained by a polycondensation reaction with an ω-linear aliphatic dicarboxylic acid.
(9) (A) 20% by weight or more of the thermoplastic resin is a mixed diamine composed of 0 to 50 mol% paraxylylenediamine and 50 to 100 mol% metaxylylenediamine, and 6 to 12 carbon atoms. The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (5), which is a polyamide resin obtained by a polycondensation reaction with an α, ω monolinear aliphatic dicarboxylic acid.
(10) The fiber-reinforced thermoplastic resin molded article according to any one of (1) to (5), which contains a polybutylene terephthalate resin and / or a polyethylene terephthalate resin as the thermoplastic resin (A).
(11) (A) As the thermoplastic resin, the intrinsic viscosity measured in a 1 to 1 (weight ratio) mixture of phenol and 1,1,2,2, -tetrachloroethane at 30 ° C. is at least 0.3. The fiber reinforced thermoplastic resin molded article according to any one of (1) to (5), comprising a polybutylene terephthalate resin having a content of ˜1.2 dl / g and a titanium content of 80 ppm or less.
(12) It is characterized by being manufactured by an injection molding method or an extrusion molding method using pellets cut to a length of 3 mm or more after coating roving-like reinforcing fibers with a thermoplastic resin. ) To (11) A fiber reinforced thermoplastic resin molded article.
(13) The method comprises the steps of injection molding or extrusion molding pellets cut to a length of 3 mm or more after coating a roving-like reinforcing fiber with a thermoplastic resin, (1) to (11) The manufacturing method of the fiber reinforced thermoplastic resin molded article of any one of these.

  According to the present invention, it is possible to obtain a fiber-reinforced thermoplastic resin molded article excellent not only in mechanical strength but also in heat resistance, dimensional accuracy, and surface appearance. Since these resin molded products can fully satisfy the required performance for weight reduction, thinning, dimensional accuracy, and appearance improvement, they can be used in a wide range of applications such as parts in the fields of automobiles, electrical and electronic equipment, and precision machinery. The industrial value of the present invention is remarkable.

Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

(A) Thermoplastic resin:
The (A) thermoplastic resin used in the present invention is not particularly limited, and may be either a crystalline thermoplastic resin or an amorphous thermoplastic resin.
Examples of the crystalline thermoplastic resin include polyamide resin, polyester resin, polyacetal resin, and polyolefin resin. Examples of the amorphous thermoplastic resin include a polycarbonate resin, a polyphenylene ether resin, and an aromatic vinyl compound polymer. Two or more of these thermoplastic resins may be used in combination.

(Polyamide resin)
The polyamide resin in the present invention is a polyamide polymer having an acid amide group (—CONH—) in the molecule and capable of being melted by heating. Specifically, various polyamide resins such as a lactam polycondensate, a polycondensate of a diamine compound and a dicarboxylic acid compound, a polycondensate of ω-aminocarboxylic acid, or a copolymerized polyamide resin or blend thereof. It is.

Examples of the lactam that is a raw material for polycondensation of polyamide resin include ε-caprolactam and ω-laurolactam.
Examples of the diamine compound include tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2-methylpentamethylene diamine, (2,2,4- or 2,4 , 4-) Trimethylhexamethylenediamine, 5-methylnonanemethylenediamine, metaxylylenediamine (MXDA), paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-amino) (Cyclohexyl) pro Emissions, bis (aminopropyl) piperazine, aliphatic, such as aminoethylpiperazine, alicyclic, and aromatic diamine compounds.
Examples of the dicarboxylic acid compound include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5- Aliphatic, alicyclic, and aromatic dicarboxylic acids such as sodium sulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.
Examples of the ω-aminocarboxylic acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, paraaminomethylbenzoic acid, and the like.

  Specific examples of polyamide resins obtained by polycondensation from these raw materials include polyamide 4, polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 56, polyamide 66, polyamide 610, polyamide 612, polyhexamethylene terephthalamide. (Polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polymetaxylylene adipamide (polyamide MXD6), polymetaxylylene decanamide, polyamide 9T, polyamide 9MT, and the like. In the present invention, these polyamide homopolymers or copolymers can be used alone or in the form of a mixture.

  Among the polyamide resins as described above, a polyamide resin widely known as MX nylon such as polyamide 6, polyamide 66, or polyamide MXD6 is more preferably used from the viewpoint of moldability and heat resistance. Among these, MX nylon is more preferable from the viewpoints of heat resistance and molded product surface appearance. When the polyamide resin is a mixture, the ratio of MX nylon in the polyamide resin is preferably 20% by weight or more, more preferably 50% by weight or more, and further preferably 70% by weight or more. preferable.

MX nylon, which is a polyamide resin preferably used here, is a xylylenediamine-based polyamide resin obtained by polycondensation of α, ω-linear aliphatic dicarboxylic acid and xylylenediamine. In the present invention, a mixed diamine composed of 0 to 50 mol% paraxylylenediamine and 50 to 100 mol% metaxylylenediamine, an α, ω-linear aliphatic dicarboxylic acid having 6 to 12 carbon atoms, A polyamide resin obtained by the polycondensation reaction is more preferable. The MX nylon has a slightly slower crystallization speed than aliphatic polyamide resins such as polyamide 66, polyamide 6, polyamide 46, and polyamide 9T. Therefore, in order to shorten the molding cycle, the MX nylon is preferably used as an aliphatic polyamide. It is preferable to mix and use a resin.
Examples of the aliphatic polyamide resin used for blending for the purpose of shortening the molding cycle include polyamide resins having a high crystallization speed, such as polyamide 66, polyamide 6, and polyamide 46, and polyamides 66 / 6T and 66 / 6T / 6I. , Polyamide 9T and other high melting point polyamide resins, and polyamide 66 or polyamide 6 is preferable from the viewpoint of economy. From the balance of moldability and physical properties, the blending ratio of the aliphatic polyamide resin is preferably 60% by weight or less in the total polyamide resin. By making the blending ratio of the aliphatic polyamide resin 60% by weight or less, the heat resistance can be kept good.

  Among α, ω-linear aliphatic dicarboxylic acids which are raw materials for MX nylon, α, ω-linear aliphatic dicarboxylic acids having 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms, such as adipic acid , Sebacic acid, suberic acid, dodecanedioic acid, eicodioic acid and the like can be suitably used. Among these α, ω-linear aliphatic dicarboxylic acids, adipic acid is particularly preferable in view of balance of moldability, molded product performance, and the like.

  The xylylenediamine used as another raw material of MX nylon is metaxylylenediamine or a mixed xylylenediamine of paraxylylenediamine and metaxylylenediamine. The molar ratio of metaxylylenediamine to paraxylylenediamine in the mixed xylylenediamine is preferably 50/50 to 100/0, and more preferably 55/45 to 100/0. It is preferable to set the molar ratio of paraxylylenediamine to 50 mol% or less because the melting point of the polyamide resin is kept low, and the polymerization of MX nylon and the molding process of the resin composition containing MX nylon are facilitated. In particular, by setting the ratio of paraxylylenediamine to 10 mol% or more, the crystallization speed of the polyamide resin can be increased and the blending amount of the aliphatic polyamide resin can be reduced, which is further preferable.

  The relative viscosity of the polyamide resin is preferably 2.0 to 4.0, more preferably 2.0 to 2.7. By setting the relative viscosity to 2.0 or more, embrittlement of the polyamide resin composition can be prevented, and by setting the viscosity to 4.0 or less, fluidity at the time of molding the polyamide resin composition can be improved. This is preferable because the molding process is easy. In the present invention, the relative viscosity means a viscosity measured using 96% sulfuric acid as a solvent, a resin concentration of 1 g / 100 ml, and a temperature of 23 ° C.

  The terminal amino group concentration of the polyamide resin is preferably 10 to 140 eq / ton, more preferably 30 to 100 eq / ton, from the viewpoint of the molecular weight of the polymer. The terminal carboxyl group concentration of the polyamide resin is preferably 10 to 140 eq / ton, more preferably 30 to 100 eq / ton, from the viewpoint of the molecular weight of the polymer.

(Polyester resin)
The polyester resin in the present invention is preferably a polymer or copolymer obtained by a polycondensation reaction of an aromatic dicarboxylic acid or a derivative thereof and an aliphatic glycol, and one type of polyester resin may be used alone. In addition, two or more kinds may be used in combination.

Examples of aromatic dicarboxylic acids or derivatives thereof include terephthalic acid, phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid, 4,4 Examples include '-benzophenone dicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, and alkyl (eg, having 1 to 4 carbon atoms) or glycol esters. Among these, terephthalic acid or a dialkyl ester thereof is more preferable, and terephthalic acid or a dimethyl ester thereof is particularly preferable. These aromatic dicarboxylic acids or derivatives thereof may be used alone or in combination of two or more.
These aromatic dicarboxylic acids or derivatives thereof may be used in combination with a small amount of other dibasic acids or polybasic acids, or alkyl or glycol esters thereof. For example, 20% by weight or less of aliphatic dicarboxylic acid such as adipic acid and sebacic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4- Mixtures of alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, polybasic acids such as trimesic acid and trimellitic acid, or esters of these alkyls or glycols can be used.

The aliphatic glycol is preferably a glycol having 2 to 20 carbon atoms, such as ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, dibutylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Is mentioned. These glycols may be used alone or in combination of two or more.
These aliphatic glycols may be used in combination with a small amount of other glycols or polyhydric alcohols. For example, alicyclic glycol such as cyclohexanediol and cyclohexanedimethanol, xylylene glycol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis ( Aromatics such as 4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, 2,2-bis (4-hydroxyethoxy-3,5-dibromophenyl) propane Polyhydric alcohols such as glycol, glycerin or pentaerythritol can be mixed and used.

  In addition to the above-described components, the polyester resin of the present invention includes, for example, lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, and p-β-hydroxyethoxy. Monofunctional components such as hydroxycarboxylic acids such as benzoic acid, alkoxycarboxylic acids, stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, tert-butylbenzoic acid and benzoylbenzoic acid can also be used as copolymerization components.

  Typical examples of polyester resins include polyalkylene terephthalate resins or copolymers based on them, and specifically, polyethylene terephthalate resins, polybutylene terephthalate resins, and these having excellent mechanical strength and heat resistance. These copolymers are preferred. When these resins are used as a copolymer, terephthalic acid is preferably 50 mol% or more of the total dicarboxylic acid component, more preferably 70 mol% or more, and even more preferably 90 mol% or more. Moreover, it is preferable that ethylene glycol or tetramethylene glycol is 50 mol% or more of all glycols, 70 mol% or more is more preferable, and 90 mol% or more is further more preferable. Use of such a polyalkylene terephthalate resin is preferable because mechanical strength and heat resistance tend to be further improved.

The polyester resin of the present invention is preferably a polybutylene terephthalate resin, and in particular, measured at a temperature of 30 ° C. in a 1: 1 (weight ratio) mixed solvent of phenol and 1,1,2,2, -tetrachloroethane. A polybutylene terephthalate resin having an intrinsic viscosity of 0.3 to 1.2 dl / g is preferred. By setting the intrinsic viscosity of the polybutylene terephthalate resin to 0.3 dl / g or more, the mechanical performance of the obtained fiber-reinforced polyester resin can be further improved. In addition, when the intrinsic viscosity is 1.2 dl / g or less, the fluidity of the fiber-reinforced polyester resin can be kept good, and the moldability tends to be improved. In addition, breakage of the reinforcing fibers in the molding process can be suppressed, the fiber length of the reinforcing fibers in the molded product can be kept longer, and a decrease in mechanical strength can be prevented. The polybutylene terephthalate resin may be used in combination with two or more polybutylene terephthalate resins having different intrinsic viscosities so as to have an intrinsic viscosity within the above range.
Moreover, in order to suppress the strength fall by hydrolysis of polybutylene terephthalate resin, it is preferable that the titanium content in polybutylene terephthalate resin is 80 ppm or less, and it is more preferable that it is 60 ppm or less. Titanium content can be adjusted with the compounding quantity of the titanium compound used at the time of manufacture of polybutylene terephthalate resin.

  As the polyester resin, a polyethylene terephthalate resin can also be preferably used. When the polyester resin is a polyethylene terephthalate resin, its intrinsic viscosity is preferably 0.5 to 0.9 dl / g. By setting the intrinsic viscosity within the above range, the molding process is facilitated, and the mechanical strength of the resulting resin composition can be further improved. The polyethylene terephthalate resin may have an intrinsic viscosity within the above range by using two or more kinds of polyethylene terephthalate resins having different intrinsic viscosities in combination.

When manufacturing a polyester resin, a well-known method is employable widely. For example, when a polybutylene terephthalate resin comprising a terephthalic acid component and a tetramethylene glycol component is produced, either a direct polymerization method or a transesterification method can be employed. The direct polymerization method is, for example, a method in which terephthalic acid and tetramethylene glycol are directly esterified, and water is generated in the initial esterification reaction. The transesterification method is a method using, for example, dimethyl terephthalate as a main raw material, and alcohol is generated by an initial transesterification reaction. The direct esterification reaction is preferable from the viewpoint of raw material costs.
When using a polymerization catalyst, it is preferable to select a titanium compound. The titanium compound is not particularly limited. Specifically, for example, inorganic titanium compounds such as titanium oxide and titanium tetrachloride, titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, tetraphenyl titanate, etc. And titanium phenolates. Of these, titanium alcoholates are preferable, tetraalkyl titanates are more preferable, and tetrabutyl titanate is particularly preferable. These polymerization catalysts are supplied as a solution of water, tetramethylene glycol or the like, and the supply amount is preferably 80 ppm or less, more preferably 60 ppm or less in terms of titanium atom per theoretical yield of the polybutylene terephthalate resin.
Further, the polyester resin may be produced by any one of a batch method and a continuous method with respect to a raw material supply or a polymer discharge form. Further, the initial esterification reaction or transesterification reaction is performed in a continuous operation, and the subsequent polycondensation is performed in a batch operation, or conversely, the initial esterification reaction or transesterification reaction is performed in a batch operation, followed by There is also a method of performing polycondensation in a continuous operation.

(Polyacetal resin)
The polyacetal resin in the present invention is a polymer produced by polymerization of formaldehyde or trioxane, and examples thereof include a homopolymer having an oxymethylene group as a repeating unit. In order to increase heat resistance and chemical resistance, it is common practice to convert end groups to ester or ether groups.
The polyacetal resin may be a block copolymer. This type of copolymer is composed of a homopolymer block having the above oxymethylene group as a repeating unit and another type of polymer block. Specific examples of other types of polymer blocks include, for example, polyalkylene glycol, polythiol, vinyl acetate, acrylic acid copolymer, hydrogenated butadiene, acrylonitrile copolymer, and the like.
The polyacetal resin may be a random copolymer. In this type of copolymer, formaldehyde and trioxane are copolymerized with other aldehydes, cyclic ethers, vinyl compounds, ketene, cyclic carbonates, epoxides, isocyanates, ethers, and the like. Specific examples of the compound to be copolymerized include ethylene oxide, 1,3-dioxolane, 1,3-dioxane, 1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene oxide and styrene oxide. In this type of copolymer, the polymerization catalyst is generally deactivated and the terminal is stabilized after cationic polymerization. A copolymer containing an oxymethylene group as a main repeating unit and containing an oxyalkylene group having 2 or more carbon atoms is widely used.

(Polyolefin resin)
The polyolefin resin in the present invention is mainly composed of α-olefin homopolymer, α-olefin copolymer, α-olefin (multiple types may be used), and other unsaturated monomers (multiple types may be used). Good) as a secondary component. Here, the copolymer may be any type of copolymer such as block, random, graft, or a composite thereof. In addition, these olefin polymers are modified by chlorination, sulfonation, carbonylation and the like.
Examples of the α-olefin include ethylene, propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and the like. Among these, an α-olefin having 2 to 8 carbon atoms is preferable because of easy availability.
Examples of the unsaturated monomer include unsaturated organic compounds such as acrylic acid, methacrylic acid (hereinafter abbreviated as “(meth) acrylic acid”), (meth) acrylic acid ester, maleic acid, and the like. Examples thereof include acids, derivatives thereof (esters, anhydrides, etc.), unsaturated aliphatic cyclic olefins, and the like.
Specific examples of polyolefin resins include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutene, poly-4-methylpentene-1, propylene-ethylene block or random copolymer, and other copolymers with ethylene. And copolymers with various monomers.

(Polycarbonate resin)
As the polycarbonate resin in the present invention, either an aromatic polycarbonate resin or an aliphatic polycarbonate resin can be used, but an aromatic polycarbonate resin is preferred.
The aromatic polycarbonate resin is a thermoplastic polymer obtained by reacting an aromatic dihydroxy compound or a small amount thereof with phosgene or a carbonic acid diester. The aromatic polycarbonate resin may be branched or a copolymer. The production method of the aromatic polycarbonate resin is not particularly limited, and can be produced by a conventionally known phosgene method (interfacial polymerization method) or a melting method (transesterification method). Moreover, when using the aromatic polycarbonate resin obtained by a melting method, you may adjust and use the amount of OH groups of a terminal group.

  Examples of the aromatic dihydroxy compound used as a raw material for the aromatic polycarbonate resin include 2,2-bis (4-hydroxyphenyl) propane (that is, bisphenol A), tetramethylbisphenol A, and bis (4-hydroxyphenyl) -p-diisopropyl. Examples thereof include benzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, and bisphenol A is preferable. In addition, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound can also be used.

  In order to obtain a branched aromatic polycarbonate resin, a part of the above-mentioned aromatic dihydroxy compound is mixed with a branching agent such as phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene- 2,4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3, 1,3 Polyhydroxy compounds such as 5-tri (4-hydroxyphenyl) benzene and 1,1,1-tri (4-hydroxyphenyl) ethane, and 3,3-bis (4-hydroxyaryl) oxindole (ie, isatin) Bisphenol), 5-chloroisatin, 5,7-dichloroisatin, 5-bromoisatin and the like may be substituted. The amount of the compound to be substituted is usually 0.01 to 10 mol%, preferably 0.1 to 2 mol%, based on the aromatic dihydroxy compound.

  As the aromatic polycarbonate resin, among the above-mentioned, polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and other aromatic dihydroxy Polycarbonate copolymers derived from the compounds are preferred. Further, it may be a copolymer mainly composed of a polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure. Furthermore, you may mix and use 2 or more types of the aromatic polycarbonate resin mentioned above.

  The molecular weight of the aromatic polycarbonate resin is preferably 13,000 to 30,000, preferably 16,000 to 28,000 as a viscosity average molecular weight converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent. More preferably, 17,000 to 24,000 is even more preferable. By setting the viscosity average molecular weight to 30,000 or less, the fluidity is kept good, and by setting the viscosity average molecular weight to 13,000 or more, the impact strength can be further improved.

(Polyphenylene ether resin)
The polyphenylene ether resin in the present invention is a homopolymer or copolymer having a phenylene ether structure represented by the following general formula (1).

一般式（１）中、２つのＲ¹は、それぞれ独立して、水素原子、ハロゲン原子、第１級若しくは第２級アルキル基、アリール基、アミノアルキル基、炭化水素オキシ基またはハロ炭化水素オキシ基を表し、２つのＲ² は、それぞれ独立して、水素原子、ハロゲン原子、第１級若しくは第２級アルキル基、アリール基、ハロアルキル基、炭化水素オキシ基またはハロ炭化水素オキシ基を表し、ｎは１０以上の整数を表す。ただし、２つのＲ¹が共に水素原子になることはない。

In general formula (1), two R ^{1 s} are each independently a hydrogen atom, a halogen atom, a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a hydrocarbonoxy group, or a halohydrocarbonoxy group. Each of the two R ^{2 s} independently represents a hydrogen atom, a halogen atom, a primary or secondary alkyl group, an aryl group, a haloalkyl group, a hydrocarbonoxy group or a halohydrocarbonoxy group; n represents an integer of 10 or more. However, the two R ^{1 s} do not become hydrogen atoms.

R ¹ and R ² are preferably a hydrogen atom, a primary or secondary alkyl group, or an aryl group. Preferable examples of the primary alkyl group include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-amyl group, isoamyl group, 2-methylbutyl group, n-hexyl group, 2, A 3-dimethylbutyl group, a 2,3- or 4-methylpentyl group, a heptyl group, etc. are mentioned. Preferable examples of the secondary alkyl group include isopropyl group, sec-butyl group, 1-ethylpropyl group and the like. Preferable examples of the aryl group include a phenyl group and a naphthyl group. In particular, R ¹ is more preferably a primary or secondary alkyl group having 1 to 4 carbon atoms or a phenyl group. R ² is more preferably a hydrogen atom.

Suitable polyphenylene ether homopolymers include, for example, poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2,6 2, such as -dipropyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether Examples thereof include polymers of 6-dialkylphenylene ether. Examples of the copolymer include various 2,6-dialkylphenol / 2,3,6-trialkylphenol copolymers.
As the polyphenylene ether resin of the present invention, poly (2,6-dimethyl-1,4-phenylene) ether and 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer are particularly preferable. Also suitable are polyphenylene ether resins containing molecular constituents that improve properties such as molecular weight, melt viscosity and impact strength.

  The intrinsic viscosity of the polyphenylene ether resin is preferably 0.2 to 0.8 dl / g, more preferably 0.2 to 0.7 dl / g as a value measured at 30 ° C. in chloroform. More preferably, it is 25-0.6 dl / g. By setting the intrinsic viscosity to 0.2 dl / g or more, a decrease in mechanical strength such as impact resistance of the resin composition can be prevented, and by setting the intrinsic viscosity to 0.8 dl / g or less, the resin fluidity is further improved. It becomes good and molding processing becomes easy.

一般式（２）中、Ｒ³は、水素原子、低級アルキル基またはハロゲン原子を表し、Ｒ⁴は、水素原子、低級アルキル基、塩素原子またはビニル基を表し、ｎは１〜５の整数を表す。 (Aromatic vinyl compound weight body)
The aromatic vinyl compound polymer is a polymer derived from a monomer compound having a structure represented by the following general formula (2).

In general formula (2), R ³ represents a hydrogen atom, a lower alkyl group or a halogen atom, R ⁴ represents a hydrogen atom, a lower alkyl group, a chlorine atom or a vinyl group, and n represents an integer of 1 to 5. To express.

  Specific examples of the aromatic vinyl compound polymer include, for example, polystyrene, rubber-reinforced polystyrene, polyvinyl chloride, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, styrene-maleic anhydride copolymer, styrene. -Maleimide copolymer etc. are mentioned.

  As the thermoplastic resin of the present invention, the above-described polyamide resin and polyester resin are preferable from the viewpoint of excellent balance of mechanical strength, oil resistance, chemical resistance, heat resistance, durability, and moldability.

(B) Flat reinforcing fiber:
The (B) flat reinforcing fiber in the present invention is a fibrous reinforcing material known as glass fiber, carbon fiber, etc., which is blended into plastic mainly for the purpose of improving mechanical strength. It is characterized by a flat shape rather than a conventional circular shape. Examples of the flat shape of the reinforcing fiber are illustrated as eyebrows, ovals, and ellipses in FIGS. 1A, 1B, and 1C of FIG. In FIG. 1, the major axis is (a), the minor axis is (b), the degree of flatness of the reinforcing fibers is the oblateness, and is represented by major axis (a) / minor axis (b). In the present invention, the flatness ratio is required to be 2.3 or more, preferably 2.3 to 5, and more preferably 3 to 4.5. By setting the aspect ratio to 2.3 or more, warpage and molding shrinkage of the molded product can be effectively improved. The major axis (a) and minor axis (b) for calculating the flatness were determined by measuring the actual size from a micrograph of the reinforcing fiber cross section.

The cross-sectional area of the (B) flat reinforcing fiber is preferably 2 × 10 ⁻⁵ to 8 × 10 ⁻³ mm ² , more preferably 8 × 10 ⁻⁵ to 8 × 10 ⁻³ mm ² , and even more preferably 8. It is * 10 < ^-5 > -8 * 10 <^-4> mm < ² >. By making the cross-sectional area within the above range, it is preferable because the handling at the time of producing the resin composition pellets used for the production and molding of the reinforcing fibers becomes easy. Furthermore, when the reinforcing fiber within the above cross-sectional area range is used, the contact area with the thermoplastic resin is increased, and a sufficient reinforcing effect can be obtained.

  The content of the (B) flat reinforcing fiber is 30 to 65% by weight, preferably 35 to 60% by weight in the total 100% by weight of the component (A) and the component (B). By controlling the content of the component (B) to 65% by weight or less, the fluidity during molding can be improved, and at the same time, the reinforcing fibers during molding can be prevented from being crushed, and the fiber length in the molded product can be reduced. Can be maintained for a long time, and a decrease in mechanical strength can be prevented. About the minimum of content, it is the same as that of the case where the reinforcing fiber of the conventional circular cross-sectional shape is used fundamentally, and improvement of mechanical strength can be confirmed in 20 weight% or more. However, if the reinforcing fiber content is less than 30% by weight, the resin fluidity during molding is good, so that the reinforcing fibers are almost oriented in the resin flow direction regardless of the cross-sectional shape of the fiber, and the dimensional accuracy (mold shrinkage) The effect of adding flat reinforcing fibers is not sufficiently exhibited with respect to surface anisotropy) and warpage, and the difference from circular cross-section fibers is not clear.

On the other hand, when the content of (B) flat reinforcing fibers is 30% by weight or more, the characteristics of the reinforcing fibers themselves begin to appear remarkably. As the content of reinforcing fibers increases, the fluidity during molding decreases.In addition, plasticization and injection during molding are performed at a low shear rate in order to prevent crushing of reinforcing fibers and ensure a long reinforcing fiber length. Since it is performed, the orientation of the reinforcing fibers in the resin flow direction tends to be further reduced. When flat reinforcing fibers are used, particularly when the flatness of the cross section is large, in addition to the resin flow in the fiber length direction, the flow of the resin in the fiber cross section long diameter (a) direction occurs. Therefore, the reinforcing fibers are easily oriented in parallel. In particular, in the vicinity of the surface of the molded product, such an orientation tendency is stronger. The effect of improving the dimensional accuracy, warpage, and surface appearance is exhibited by the influence of the fiber orientation characteristic of such flat reinforcing fibers, which does not normally occur in a circular cross section.
Further, since the reinforcing fibers are oriented along the major axis (a) direction and the fiber length of the reinforcing fibers in the molded product is long, the fiber-reinforced thermoplastic resin molded product of the present invention is heated. However, it is considered that the matrix resin is difficult to bend and can exhibit higher heat resistance.
Since the influence of the orientation of the fibers along the direction of the major axis (a) appears more prominently when the cross section is oval, reinforcing fibers having an oval cross section are preferable in the present invention. When the cross-sectional shape is an eyebrow or an ellipse, the flow of the resin in the major axis (a) direction is hindered by the eyebrow-shaped groove or the ellipse weir, and a part of the flow flows in the fiber length direction. Due to the tendency, the arrangement of reinforcing fibers along the direction (a) hardly occurs, and the improvement effect on dimensional accuracy, warpage, heat resistance, and surface appearance is slightly inferior to that of an oval reinforcing fiber. In addition, in this invention, an oval is substantially parallel to the symmetrical position with respect to the gravity center of a fiber cross section as shown, for example in (b) of FIG. 1 of Japanese Patent Publication No. 2-60494. A shape having a part.

  The (B) flat reinforcing fiber is preferably surface-treated with a sizing agent and / or a surface treatment agent, if necessary, from the viewpoint of handling and adhesion to the resin. As the sizing agent and / or surface treating agent, for example, known sizing agents and surface treating agents such as epoxy compounds, isocyanate compounds, silane compounds, titanate compounds, and the like can be used, and the amount of adhesion thereof. Is preferably 0.05% by weight or more of the weight of the reinforcing fiber. Reinforcing fibers may be used after being subjected to surface treatment or convergence treatment with these compounds in advance, or may be added simultaneously with the production of the resin composition pellets used in the resin molded product of the present invention.

  The flat reinforcing fiber (B) is spun by using a nozzle having an appropriate hole shape such as an oval, eyebrow, ellipse or rectangular slit as a bushing used for discharging a melt, for example. Can be manufactured. Also, a melt is spun from a plurality of nozzles provided in close proximity with various cross-sectional shapes (including a circular cross-section), and the spun melt filaments are joined together to form a single filament. Can be manufactured. Such manufacturing techniques are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 7-291649 and 2000-344541.

In the present invention, the weight average fiber length of the reinforcing fibers in the molded product is 1 mm or more, preferably 1 to 10 mm, and more preferably 1.5 to 8 mm. In particular, in the present invention, the ratio of the reinforcing fibers that are 1 mm or more is preferably 30% by weight or more of the total reinforcing fibers from the viewpoints of mechanical strength and strength retention at high temperatures. The proportion of reinforcing fibers having a weight average fiber length of 1 mm or more in the molded product is more preferably 33% by weight to 95% by weight in all reinforcing fibers.
The measurement of the reinforcing fiber length was performed on the remaining reinforcing fiber after cutting out a sample of about 5 g from the center of the molded product and ashing in an electric furnace at a temperature of 600 ° C. for 2 hours. The obtained reinforcing fiber was dispersed in a neutral surfactant aqueous solution so as not to break, and the dispersed aqueous solution was transferred onto a slide glass using a pipette and photographed with a microscope. The photographic image was measured for 1000 to 2000 reinforcing fibers using image analysis software.

In order to achieve the above conditions, at least such a fiber length needs to be secured at least in the stage of the resin composition pellets to be subjected to injection or extrusion molding. Examples of the method for producing the resin composition pellets in which the fiber length is ensured include, for example, a method in which a reinforced fiber mat is pressed from both sides with a molten resin sheet, and a rectangular parallelepiped is formed with a sheet cutter, In this manner, a method of covering the reinforcing fiber roving surface with a resin to form a strand and then cutting it into pellets is adopted. Moreover, when manufacturing a resin composition pellet by melt kneading | mixing, it is good to select the kneading | mixing conditions that a reinforcement fiber is not damaged at the time of kneading | mixing. Among these methods, the pulverization molding method (US Pat. No. 3,042,570, JP-A No. 305,570) can be used because the reinforcing fibers can be efficiently arranged in parallel to the length direction of the pellet and the dispersion of the fibers can be improved. Sho 53-50279, etc.) is preferably employed.
The pultrusion method is basically a method of impregnating a resin while drawing a continuous bundle of reinforcing fibers, and is a known technique (a roving shape of reinforcing fibers, reinforcing fibers) disclosed in many various patents. All of the preheating method, the fiber opening method, the method of impregnating the thermoplastic resin with the reinforcing fiber, the shaping method after the resin impregnation, the cooling method, the cutting method, etc. can be used. Considering the breakage of reinforcing fibers in injection or extrusion molding, the size of the long fiber reinforced pellets is that the pellet length (that is, the length of the reinforcing fibers) is 1 mm or more, preferably 3 mm or more, more preferably The pellet length is 3 to 50 mm, and the pellet diameter is 1.5 to 4 mm. By injection and extrusion molding using long fiber reinforced pellets containing reinforcing fibers of the same length as such pellets, the increase in bulk density is suppressed, bridges occur in the hopper during molding, This prevents the phenomenon that the biting in becomes worse, and the molded product of the present invention can be produced efficiently and stably.

When producing resin composition pellets by melt kneading, for example, various extruders, Brabender plastographs, lab plast mills, kneaders, Banbury mixers and the like are used. In this invention, the method of using the twin-screw extruder which has the equipment which can deaerate from a vent port as a kneading machine is preferable. Further, (A) the thermoplastic resin and the additive blended as necessary may be mixed in advance with a ribbon blender, a Henschel mixer or the like, or may be put into a melt kneader without mixing. However, (B) flat reinforcing fibers are preferably added separately from a dedicated inlet provided on the downstream side of the twin-screw extruder, and the mixing time and the number of rotations are adjusted so as to minimize the damage of the reinforcing fibers due to mixing. More preferably.
Although the heating temperature at the time of melt kneading depends on the type of thermoplastic resin used, in the present invention, in order to reduce the pressure of the molten resin at the time of melt kneading, the plasticizing temperature of the molten resin is made higher than usual. It is preferable to set. For example, when melt-kneading a polyamide amide resin or a polyester resin, plasticization is usually performed at 220 to 280 ° C., but in order to reduce the pressure of the molten resin during kneading and to reduce the breakage of the reinforcing fiber due to mixing as much as possible. It is preferable to plasticize at a temperature higher than usual, for example, 260 to 280 ° C.

  By adopting any one of the above conditions or combining a plurality of conditions, the fiber length of the reinforcing fibers in the resin composition pellet can be kept longer. When manufacturing a resin composition pellet by melt-kneading, the preferable fiber length of the reinforcing fiber in the resin composition pellet is 1 to 20 mm, more preferably 1.5 to 20 mm, and further preferably 2 to 15 mm. is there.

  In addition to the method described above, (A) a thermoplastic resin, (B) a flat reinforcing fiber, and additive components blended as necessary are mixed in advance using a ribbon blender, a Henschel mixer, a drum blender, or the like. It is also effective to use the dry blend as it is for molding without melt-kneading. When this method is used, it is possible to avoid breakage of the reinforcing fibers in the melt kneading, so that it is possible to keep the reinforcing fiber length in the obtained molded product longer.

As a method for increasing the ratio of reinforcing fibers having a fiber length of 1 mm or more in a molded product so as not to break the reinforcing fibers in injection and extrusion molding, the above-mentioned long fiber reinforced pellets, melt-kneaded resin composition pellets and dry blended products are used. In addition to the method used, for example, screw configuration, processing of the inner wall of the screw or cylinder, selection of molding machine conditions such as nozzle diameter, mold structure, etc., adjustment of molding conditions such as plasticization, metering, injection, etc. Various methods, such as addition of a component, are mentioned.
As a molding machine, for example, a method of using a screw with a looser compression type so as not to apply abrupt shearing to unmelted resin, or in-line screw type molding machine, a backflow prevention ring at the screw tip, etc. A method of increasing the clearance can be adopted.
In adjusting the molding conditions, it is particularly necessary to avoid plasticization and injection at a high shear rate. In the present invention, it is preferable to adjust, for example, cylinder temperature, back pressure, screw rotation speed, injection speed, and the like as conditions during plasticization, weighing, and injection. The cylinder temperature needs to be appropriately adjusted depending on the type of the thermoplastic resin to be used. For example, when the thermoplastic resin is a polyamide resin, the cylinder temperature is preferably set to 270 to 320 ° C, more preferably 280 to 300 ° C. To do. When the thermoplastic resin is a polyester resin, the temperature is preferably set to 250 to 300 ° C, more preferably 260 to 280 ° C.
In the case of adjusting the back pressure, it is preferably set to 0.2 to 5 MPa, more preferably 0.3 to 3 MPa. When adjusting a screw rotation speed, Preferably it sets to 30-150 rpm, More preferably, it is set to 40-100 rpm. When adjusting the injection speed, it is preferably set to 10 to 100 mm / sec, more preferably 10 to 50 mm / sec.
Adjust the molding machine conditions, cylinder temperature, back pressure, screw rotation speed, injection speed, and other molding conditions within the above-mentioned preferable range so as not to impair the moldability, reinforcing fiber dispersibility, and molded article physical properties. By combining two or more conditions within these preferable ranges, it is possible to mold at an appropriate melt viscosity and pressure, to suppress the breakage of reinforcing fibers, and to produce a molded product having an excellent surface appearance. It is possible to obtain.
A method of adding other components to the molding material is also effective. For example, a method of adding a lubricant to lower the resin melt viscosity at the time of injection molding, a method of adding a plasticizer to improve resin fluidity, and the like are effective.
Examples of the lubricant include fatty acid metal salts such as stearic acid metal salts and montanic acid metal salts, long-chain saturated fatty acid waxes, amide waxes, and the like, which should be added within a range that does not significantly affect mechanical properties. Is preferred. For example, the blending amount of the lubricant is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A).
Examples of plasticizers include pyrrolidone carboxylic acid compounds and parahydroxybenzoic acid, which are solid at room temperature but liquefy at the melting temperature, and are added to the extent that they do not significantly affect mechanical properties. Is preferred. The amount of the plasticizer to be blended is, for example, preferably 0.01 to 5 parts by weight, more preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A).

  In addition, when producing the above resin composition pellets, in addition to the above-mentioned essential components and components added as necessary, crystals such as talc, as long as the properties of the resin composition of the present invention are not impaired. Stabilizers such as nucleating agents, copper halides (for example, copper iodide, copper chloride, copper bromide) and / or alkali metal halides (for example, potassium iodide, potassium bromide), hindered phenols -Based, phosphite-based antioxidants, wollastonite and other inorganic fillers other than component (B), releasability improvers, flame retardants and / or flame retardant aids, pigments, dyes, dispersants, electrification Inhibitors, UV absorbers, impact modifiers and other well-known additives can be blended.

  In the present invention, when the thermoplastic resin (A) is crystalline, it is preferable to add a crystal nucleating agent in order to increase the crystallization speed and improve the moldability among the above-mentioned additives. Examples of the crystal nucleating agent generally include inorganic crystal nucleating agents such as talc and boron nitride, but organic crystal nucleating agents may be added. The addition amount of the crystal nucleating agent is 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the (A) thermoplastic resin. By making the blending amount 0.01 parts by weight or more, the effect as a crystal nucleating agent can be sufficiently exerted, and by making the blending amount 10 parts by weight or less, the strength and impact value are reduced by the foreign matter effect. This can be prevented and is preferable at low cost without adding more than necessary.

  In order that the thermoplastic resin composition of this invention may improve the mold release property at the time of shaping | molding, it is preferable to mix | blend a mold release improvement agent. Examples of releasability improvers include long-chain aliphatic carboxylic acids having 14 or more carbon atoms such as stearic acid and palmitic acid and derivatives thereof (for example, esters, alkali metal salts, alkaline earth metal salts, amides, etc.) Higher aliphatic alcohols having 14 or more carbon atoms such as stearyl alcohol and derivatives thereof, amines having 14 or more carbon atoms such as stearylamine and derivatives thereof, waxes such as low molecular weight polyethylene wax and paraffin wax, silicone oil, silicone gum, etc. Is mentioned. A compounding quantity is 0.01-5 weight part normally with respect to 100 weight part of (A) thermoplastic resins, Preferably it is 0.1-3 weight part. By setting the blending amount within the above range, the effect of improving the releasability can be sufficiently exhibited, and generation of gas during molding and deterioration of the appearance of the molded product surface can be prevented, which is preferable.

  Examples of the impact resistance improver include thermoplastic elastomers such as α-olefins, styrenes, acrylics, and silicones, and core-shell polymers such as methyl methacrylate-butadiene-styrene resins. A compounding quantity is 1-30 weight part normally with respect to 100 weight part of (A) thermoplastic resins, Preferably it is 1-20 weight part, More preferably, it is 3-10 weight part.

  Specific examples of the inorganic filler other than the component (B) include, for example, glass fibers, carbon fibers, and aramid fibers having a circular cross section, mica, talc, wollastonite, potassium titanate, calcium carbonate, silica, and the like. It is done. A compounding quantity is 1-50 weight part normally with respect to 100 weight part of (A) thermoplastic resins, Preferably it is 3-40 weight part, More preferably, it is 5-30 weight part.

  Furthermore, the thermoplastic resin composition used in the present invention may contain a thermosetting resin as a part of the thermoplastic resin (A) as long as it does not impair the effects of the present invention. As a thermosetting resin, a phenol resin, a melamine resin, a silicone resin, an epoxy resin etc. are mentioned, for example. When such a thermosetting resin is included, the blending amount of the thermosetting resin is preferably 50% by weight or less, more preferably 30% by weight or less in the (A) thermoplastic resin.

  Moreover, in this invention, you may mix | blend and use a recycled resin as a part of (A) thermoplastic resin. There are no particular restrictions on the recycled resin, purge resin, sprue, runner during molding, defective products generated during molding, secondary processing, assembly processes, etc., recovered after use for the intended use Recycled products from various stages such as molded products can be used. When the recycled resin is used, the blending amount thereof is preferably 50% by weight or less, more preferably 30% by weight or less, out of the total 100% by weight of (A) the thermoplastic resin and the recycled resin. By making the blending amount of the recycled resin 50% by weight or less, the mechanical strength, the dimensional stability of the molded product, the appearance and the like can be improved. In addition, when (A) a thermoplastic resin and a recycled resin are mixed and used for molding, it is preferable to approximate their shapes and sizes as much as possible in order to prevent classification in the molding process.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

Example 1
[Production method of fiber reinforced polyamide resin pellets]
Production method of pellets used in Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-3, 1-6 to 1-9, 1-11, 1-12 While being drawn, it was impregnated with a polyamide resin melt (resin temperature 280 ° C.), then taken as a strand through a shaping die and cut. In Example 1-2, the length was 3 mm, and other examples and comparative examples In, a long fiber reinforced polyamide resin composition pellet having a length of 12 mm was obtained. The content of reinforcing fibers in the pellets was adjusted by adjusting the ratio between the glass fiber roving amount and the polyamide resin amount. In each example and comparative example, the cross-sectional shape of the glass fiber and the type of polyamide resin are as shown in Tables 1 to 3.

Manufacturing method of pellets used in Comparative Examples 1-4, 1-5, 1-10 After blending other than glass fiber chopped strands at the blending ratios shown in Tables 1 and 2, twin screw extruder (manufactured by Nippon Steel Works) , "TEX30XCT", barrel 9 block configuration), under the conditions of a resin temperature of 280 ° C and a screw rotation speed of 250 rpm, the above dry blend other than glass fiber is the fifth from the hopper, and the glass fiber is counted from the hopper side. It was supplied from the block through a side feeder, melted and kneaded, and cut to a length of 3 mm to produce pellets for injection molding.

  After drying the polyamide resin composition pellets of Examples and Comparative Examples obtained by the above methods at 80 ° C. for 12 hours, molded articles for the following evaluation tests were produced under the following molding conditions. The obtained molded product was evaluated according to the following conditions.

[Molding condition]
In Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-10 described in Tables 1 and 2 using an injection molding machine (manufactured by Nippon Steel Works, “J150E-P-2M”), Using a standard type screw, the cylinder temperature was 280 ° C., the mold temperature was 120 ° C., the screw rotation speed was 65 rpm, the back pressure was 6.0 MPa in Comparative Example 1-3, and the other examples were conditions of 0.4 MPa. In Examples 1-6 to 1-8 and Comparative Examples 1-11 and 1-12 described in No. 3, a slow compression type screw is used, the mold temperature is 120 ° C., the cylinder temperature, the back pressure, and the screw rotation speed are set. Under the conditions shown in Table 3, the following mechanical strength measurement ISO test pieces, molding shrinkage measurement test pieces, warpage amount measurement test pieces, and surface appearance evaluation test pieces were prepared.

[Fiber length of fiber length of 1 mm or more and average fiber length evaluation method]
About 5 g of a sample is cut out from the center of each of the test pieces for bending test, molding shrinkage measurement, and warpage measurement produced by the method described above, and an electric furnace at 600 ° C. (“Electricity” manufactured by Toyo Manufacturing Co., Ltd.). After ashing in a muffle furnace KM-28 ") for 2 hours and burning only the thermoplastic resin component, the glass fiber was gently spread and dispersed in an aqueous neutral surfactant solution with forceps so as not to break the glass fiber. The aqueous dispersion was transferred onto a slide glass using a pipette, and photographs were taken at a magnification of 20 times and 40 times with a microscope. The obtained photograph was measured for 1000 to 2000 glass fibers using image analysis software ("Image-Pro Plus" manufactured by Planetron), and the ratio of the fiber length of 1 mm or more was measured. Further, the weight average value of the fiber length was defined as the weight average fiber length, and the number average value was defined as the number average fiber length.

[Mechanical strength measurement method]
Using the ISO test piece obtained under the above molding conditions, a tensile test according to the ISO 527 standard, a bending test according to the ISO 178 standard, and a Charpy impact test (notched) according to the ISO 179 standard were performed. Moreover, in order to evaluate heat resistance, the bending test was performed, heating a test piece to 120 degrees C or less.

[Method of measuring molding shrinkage]
Under the above molding conditions, a rectangular flat plate having a length of 100 mm, a width of 100 mm, and a thickness of 2 mm was molded with a film gate mold, and molding shrinkage in the resin flow direction (MD) and the flow perpendicular direction (TD) was measured. Both MD and TD have low average shrinkage, and the ratio of MD and TD molding shrinkage (anisotropy MD / TD) is close to 1 and the anisotropy is small, the mold design is easier and the dimensional accuracy is better. Is generally preferable.

[Warpage measurement method]
Under the above molding conditions, a disc having a diameter of 100 mm and a thickness of 1.6 mm (a gate is a one-point gate on the circumference) was produced. One end of the disk was fixed to a flat plate, and the height of the most lifted portion when the opposite side was lifted from the flat plate was measured and used as the amount of warpage. A smaller value is preferable because the molded product has no distortion.

[Surface appearance evaluation method]
A flat plate test piece having a length of 100 mm, a width of 100 mm, and a thickness of 2 mm was produced under the above molding conditions.
The surface of the obtained test piece was visually observed, and the appearance was evaluated with the glass fiber floating up. A glass fiber that is not lifted up and has a very good surface condition ◎, a product that is within the acceptable appearance range of general molded products, a glass fiber that is partially lifted △, and a fairly wide Glass fibers were observed to float over the range, and those outside the allowable range were marked as x.

[raw materials]
(A) Polyamide resin:
(A-1) MX nylon; manufactured by Mitsubishi Gas Chemical Co., Ltd., “trade name: MX nylon 6000”, relative viscosity (measured in 96% sulfuric acid, concentration 1 g / 100 ml, 23 ° C.) 2.14
(A-2) Polyamide 6; manufactured by Mitsubishi Engineering Plastics Co., Ltd., “trade name: Novamid (registered trademark) 1007J”, relative viscosity (measured in 96% sulfuric acid, concentration 1 g / 100 ml, 23 ° C.) 2.14
(B) Reinforcing fiber:
(B-1) Modified cross-section glass fiber roving; manufactured by Nittobo Co., Ltd., oval (FF), major axis (a) = 28 μm, minor axis (b) = 7 μm, flatness ratio 4
(B-2) Modified cross-section glass fiber roving; manufactured by Nittobo Co., Ltd., eyebrows (HIS), major axis (a) = 20 μm, minor axis (b) = 10 μm, flatness ratio 2
(B-3) Circular section glass fiber roving; manufactured by Nittobo Co., Ltd., circular, fiber diameter 13 μm
(B-4) Modified cross-section glass fiber chopped strand; manufactured by Nittobo Co., Ltd., oval (FF), major axis (a) = 28 μ, minor axis (b) = 7 μm, flatness ratio 4, fiber length 3 mm
(B-5) Circular cross-section glass fiber chopped strand; manufactured by Nittobo Co., Ltd., circular, fiber diameter 13 μm, fiber length 3 mm

Table 1 shows examples and comparative examples using MX nylon as the polyamide resin. From the results, the following was confirmed.
(1) Comparative Example 1-1 is an example having the same resin composition as Examples 1-1 and 1-2, and using circular glass fibers as reinforcing fibers. In this case, even if the average glass fiber length in the molded product and the glass fiber ratio of 1 mm or more are about the same as in Example 1-1, the average glass fiber length is longer than that in Example 1-2, and 1 mm. Even if the glass fiber ratio is large, the mechanical strength, heat resistance, molding shrinkage, warpage, and surface appearance all decrease. Further, as in Comparative Example 1-2, even when flat glass fibers are used as reinforcing fibers, when the flatness is smaller than the range of the present invention, mechanical strength, heat resistance, molding shrinkage, warpage Property and surface appearance do not achieve the goals of the present invention.
(2) Comparative Example 1-3 is an example in which the resin composition is the same as in Examples 1-1 and 1-2, the average glass fiber length in the molded product is shortened, and the glass fiber ratio of 1 mm or more is adjusted to be small. . In this case, the Charpy impact strength and the bending strength at 120 ° C. are greatly reduced, and the molding shrinkage rate and warpage do not achieve the target of the present invention.
(3) Comparative Examples 1-4 and 1-5 are examples in which glass fibers are blended in the form of chopped strands.
In Comparative Example 1-4, the same flat glass fiber as in Examples 1-1 and 1-2 is used, and in Comparative Example 1-5, the same circular glass fiber as in Comparative Example 1-2 is used. The fiber ratio of 1 mm or more is low. In these comparative examples, the Charpy impact strength, the bending strength at 120 ° C., and the elastic modulus are particularly lowered, and the molding shrinkage, warpage, and surface appearance are also lowered.
(4) Comparative Examples 1-6 and 1-7 are cases where the blending ratio of MX nylon and glass fiber is 80/20 and is different from the composition ratios of the above (1) to (3). The flat glass fiber of the invention is an example using a circular glass fiber in Comparative Example 1-7. When the amount of glass fiber is less than the range of the present invention, no difference in mechanical strength, molding shrinkage, warpage, and surface appearance can be confirmed even when flat glass fiber or circular glass fiber is used. The effect of flat glass fiber is not exhibited.

Table 2 shows examples and comparative examples using polyamide 6 as a polyamide resin and a mixture of polyamide 6 and MX nylon. The following is estimated from the results.
(5) Examples 1-3 to 1-5 are all excellent in mechanical strength, heat resistance, molding shrinkage, warpage, and surface appearance.
(6) Comparative Example 1-8 is an example in which flat glass fibers having a flatness ratio of 2 are used as reinforcing fibers.
In this case, compared with Example 1-4 using the glass fiber of flatness ratio 4, mechanical strength falls significantly. In particular, the bending strength and elastic modulus at 120 ° C. are remarkably lowered, and the heat resistance is lowered.
(7) In Comparative Examples 1-9 and 1-10, the blending ratio of polyamide 6 and glass fiber is 80/20, Comparative Example 1-9 is a glass fiber having a flatness ratio of 4, and Comparative Example 1-10 is a circular glass. This is an example in which fibers are used in the form of chopped strands. When the amount of glass fiber is less than the range of the present invention, the effect of flat glass fiber is even when compared with a resin molded product having a circular fiber cross section and a fiber length ratio of 1% or more as low as 2%. This is not demonstrated, and this is the same as the tendency of (4) above.

Table 3 shows the results of confirming the effects of the cylinder temperature, back pressure, and screw rotation speed conditions when the screw type of the injection molding machine used in the examples of Tables 1 and 2 was changed to the slow compression type. .
(8) From the results of Examples 1-6 and 1-7 and Comparative Example 1-11, it can be seen that the average glass fiber length and the glass fiber ratio of 1 mm or more decrease as the back pressure is increased. When the back pressure is increased to 6.0 MPa as in Comparative Example 1-11, the average glass fiber length and the glass fiber ratio of 1 mm or more are below the range of the present application, and the mechanical strength is reduced.
(9) From the results of Example 1-8 and Comparative Example 1-12, it can be seen that when the screw rotation speed is increased, the average glass fiber length and the glass fiber ratio of 1 mm or more are decreased. As in Comparative Example 1-12, when the screw rotation speed is increased to 120 rpm, the average glass fiber length and the glass fiber ratio of 1 mm or more fall below the range of the present application, and the mechanical strength decreases.

Example 2
[Production method of glass fiber reinforced polyester resin pellets]
Production method of pellets used in Examples 2-1 and 2-4 and Comparative Examples 2-4 and 2-5 (B-1) Continuous flat glass fiber roving (manufactured by Nittobo Co., Ltd., oval (FF), major axis) (A) = 28 μm, short diameter (b) = 7 μm, flatness ratio 4) is opened and passed through the impregnation die while being drawn, impregnated with the molten resin supplied to the impregnation die, and shaped, Using a pultrusion method for cooling and cutting, (B-1) long fiber reinforced polyester resin pellets having a glass fiber content of 50% by weight and a pellet length of 12 mm were produced. As the resin, (A-1) polybutylene terephthalate resin (manufactured by Mitsubishi Engineering Plastics Co., Ltd., “trade name: NOVADURAN (registered trademark) 5008”, intrinsic viscosity 0.85 dl / g) was melted and used. The glass fiber in the obtained pellet had a diameter of 16 μm, the fiber length was 12 mm, which was the same as the pellet, and was arranged in parallel in the length direction of the pellet.

Manufacturing method of pellet used in Example 2-2 In Example 2-1, by adjusting the ratio of (B-1) flat glass fiber roving amount and (A-1) polybutylene terephthalate resin amount, ( B-1) A long fiber reinforced polyester resin pellet was produced in the same manner as in Example 2-1, except that the glass fiber content was changed to 30% by weight.

Production method of pellets used in Example 2-3 In Example 2-1, the resin components were (A-1) polybutylene terephthalate resin and (A-2) polyethylene terephthalate resin (Mitsubishi Chemical Corporation "Products" A long fiber reinforced polyester resin pellet was produced in the same manner as in Example 2-1, except that the mixture was changed to a mixture having a name of NOVAPEX (registered trademark) GS385 ”and an intrinsic viscosity of 0.65 dl / g). At this time, the weight ratio of (A-1) polybutylene terephthalate resin to (A-2) polyethylene terephthalate resin was (A-1) :( A-2) = 40: 10.

Manufacturing method of pellet used in Example 2-5 A long fiber reinforced polyester resin pellet was manufactured in the same manner as in Example 2-1, except that the pellet length was 9 mm.

Manufacturing method of pellet used in Comparative Example 2-1 In Example 2-1, the reinforcing fiber was changed to (B-2) circular glass fiber roving having a circular cross section (circle manufactured by Nittobo Co., Ltd., fiber diameter = 13 μm). Except for the above, long fiber reinforced polyester resin pellets were produced in the same manner as in Example 2-1.

Production method of pellets used in Comparative Example 2-2 (A-1) Polybutylene terephthalate resin and (B-3) flat glass fiber chopped strand (manufactured by Nittobo Co., Ltd., oval (FF), major axis (a) = 28 μm The short diameter (b) = 7 μm, the flatness ratio 4, and the fiber length 3 mm were pelletized using a twin screw extruder (“TEX30XCT” manufactured by Nippon Steel Works, barrel 9 block configuration). The resin temperature at this time is 280 ° C., the screw rotation speed is 250 rpm, (A-1) polybutylene terephthalate resin is from the hopper, (B-3) flat glass fiber chopped strand is from the fifth block counting from the hopper side. The mixture was supplied by a side feeder, melted and kneaded, and cut into a length of 3 mm to produce fiber reinforced polyester resin pellets.

Manufacturing method of pellet used in Comparative Example 2-3 In Comparative Example 2-2, the reinforcing fiber was made of (B-4) circular glass fiber chopped strand having a circular cross section (manufactured by Nittobo Co., Ltd., circular, fiber diameter = 13 μm, A fiber-reinforced polyester resin pellet was produced in the same manner as in Comparative Example 2-2 except that the fiber length was changed to 3 mm.

Production method of pellets used in Comparative Example 2-6 In Example 2-1, by adjusting the ratio of (B-1) flat glass fiber roving amount and (A-1) polybutylene terephthalate resin amount, ( B-1) A long fiber reinforced polyester resin pellet was produced in the same manner as in Example 2-1, except that the glass fiber content was changed to 15% by weight.

Production method of pellets used in Comparative Example 2-7 In Comparative Example 2-1, by adjusting the ratio of (B-2) the amount of roving glass fiber and (A-1) the amount of polybutylene terephthalate resin ( B-1) A long fiber reinforced polyester resin pellet was produced in the same manner as in Comparative Example 2-1, except that the glass fiber content was changed to 15% by weight.

[Conditions for injection molding]
The obtained fiber-reinforced polyester resin pellets were dried at 120 ° C. for 5 hours, and then the general screw was used in Example 2-4 on an injection molding machine (“J150E-P-2M” manufactured by Nippon Steel Works). In Examples and Comparative Examples other than 2-4, a slow compression screw was used, the cylinder temperature was 275 ° C., the mold temperature was 80 ° C., the screw rotation speed was 80 rpm, and the back pressure was 6.0 MPa in Comparative Examples 2-4 and 2-5. In other examples and comparative examples, under the condition of 0.6 MPa, the following ISO strength test piece for measuring mechanical strength and deflection temperature under load, test piece for warpage measurement having a diameter of 100 mm and a thickness of 1.6 mm (the gate is a circumference) A test piece for surface appearance evaluation having an upper one-point gate), 100 mm in length, 100 mm in width, and 2 mm in thickness was produced. Using the obtained molded product, the fiber content of fiber length of 1 mm or more and the weight average fiber length evaluation, surface appearance evaluation is performed in the same manner as in Example 1 above, and the mechanical strength, the deflection temperature under load and the warpage are as follows: Evaluation was performed according to the following conditions. The results are shown in Tables 4 and 5.

[Measuring method of mechanical strength and deflection temperature under load]
Using the ISO test piece obtained under the above molding conditions, a tensile test according to the ISO 527 standard, a bending test according to the ISO 178 standard, and a Charpy impact test (without notch) according to the ISO 179 standard were performed. The deflection temperature under load (1.80 MPa) was measured according to ISO75 standard, and used as an index of heat resistance.

[Evaluation method of warpage]
One end of the test piece for warpage evaluation obtained under the above molding conditions was fixed to a precision surface plate (JIS B7513), the state where the opposite side was lifted from the precision surface plate was visually observed, and the amount of lift was measured as the amount of warpage. ◎ If there is no lift and the warpage is very good ◎, the lift can be confirmed a little, but the warp amount is 5mm or less, ○ that is judged as no problem as an actual molded product, ○, the warp amount exceeds 5mm A value of 10 mm or less, which was judged to be a problem as an actual molded product, was indicated by Δ, and a value of warpage exceeding 10 mm and a large lift was indicated by ×.

From the results of Tables 4 and 5, the following was confirmed.
(1) Examples 2-1 to 2-5 are cases where polybutylene terephthalate resin or a mixture of polybutylene terephthalate resin and polyethylene terephthalate resin is used as the resin component, and the weight average fiber length in the molded product is It is an example within the scope of the invention. It can be seen that all examples have good mechanical strength, heat resistance, warpage of molded products, and appearance.
(2) In Example 2-1 and Comparative Example 2-1, the glass fiber ratio in the resin pellet is the same, and the glass fiber cross section is flat (Example 2-1) and circular (Comparative Example 2-1). This is an example. From the comparison between Example 2-1 and Comparative Example 2-1, it can be seen that by using a glass fiber having a flat cross section, the mechanical strength and heat resistance can be improved, and the warpage and appearance of the molded product can be greatly improved.
(3) In Example 2-1 and Comparative Example 2-2, a flat cross-section glass fiber used for resin pellet production is used in the form of roving (Example 2-1) and chopped strand (Comparative Example 2-2). It is an example. By using the glass fiber in the roving form, the fiber length in the resin pellet becomes longer, so the fiber length in the molded product using the resin pellet can be kept longer, and the mechanical strength, heat resistance, molded product Warpage and appearance can be further improved.
In addition, Comparative Examples 2-1 and 2-3 are examples in which the circular cross-section glass fibers used for resin pellet production are used in the form of roving (Comparative Example 2-1) and chopped strands (Comparative Example 2-3). is there. Since Comparative Example 2-3 uses chopped strands, the fiber length in the molded product is also short, and the obtained molded product cannot achieve the object of the present invention. On the other hand, in Comparative Example 2-1, since the glass fiber in the form of roving is used, the fiber length in the molded product can be kept long. However, since the glass fiber cross section is circular, the warpage and appearance of the molded product cannot achieve the object of the present invention.
(4) Example 2-1 and Comparative Examples 2-4 and 2-5 are examples in which the resin pellet composition is the same and the molding conditions at the time of injection molding are different. From these comparisons, it can be seen that by reducing the back pressure, it is possible to prevent breakage of the glass fibers in the molded article and to further increase the ratio of 1 mm or more and the weight average fiber length. When the back pressure is high and the glass fiber in the molded product does not satisfy the range defined in the present invention, it can be seen that the object of the present application cannot be achieved.
(5) In Comparative Examples 2-6 and 2-7, the blending ratio of polybutylene terephthalate and glass fiber is 85:15, Comparative Example 2-6 is the flat glass fiber of the present invention, and Comparative Example 2-7 is circular. This is an example using glass fiber. Even if the weight average fiber length in the molded product is within the range of the present invention, if the amount of glass fiber is less than the range of the present invention, even when using flat glass fiber or circular glass fiber, In any case, the mechanical strength, heat resistance, and warpage of the molded product are not improved, and in particular, the effect of the flat cross-section glass fiber is not exhibited.
(6) In Examples 2-1 and 2-4, the ratio of glass fibers in the resin pellets is the same, and the screw type of the molding machine used for injection molding is a slow compression type (Example 2-1) and a general type. This is an example of (Example 2-4). As for the screw used for injection molding, it is possible to increase the ratio of the fiber length of 1 mm or more and the weight average fiber length in the molded product by using the slow compression type screw less than the general type screw. It can be seen that an excellent molded product can be obtained due to mechanical strength, heat resistance, and warpage of the molded product.
In Examples 2-1 and 2-5, the ratio of the glass fibers in the resin pellets is the same, and the resin pellets have a length of 12 mm (Example 2-1) and 9 mm at the stage of manufacturing the resin pellets used for injection molding. This is an example of (Example 2-5). It is possible to increase the fiber length of the reinforcing fiber in the pellet by increasing the pellet length of the resin pellet. When molding a molded product using such a resin pellet, the reinforcing fiber in the molded product is also reduced. It can be seen that a molded article that can be kept longer and that is superior in mechanical strength can be obtained.

As described in detail above, the present invention can be expected to have the following advantageous effects and has an extremely high industrial utility value.
That is, the present invention can obtain a fiber-reinforced thermoplastic resin molded article excellent in not only mechanical strength but also heat resistance, surface appearance, and dimensional accuracy. The required performance for improvement can be sufficiently satisfied, and it can be used for a wide range of applications such as parts in the fields of automobiles, electrical and electronic equipment, and precision machinery.

Claims (13)

(A) In a molded article made of a thermoplastic resin composition containing 70 to 35% by weight of a thermoplastic resin and (B) 30 to 65% by weight of a reinforcing fiber having a flat shape with a cross section of 2.3 or more according to the following formula: A fiber-reinforced thermoplastic resin molded product, wherein the weight average fiber length of the reinforcing fibers in the molded product is 1 mm or more.
Flatness ratio = reinforcing fiber long diameter (a) / reinforcing fiber short diameter (b)   (B) The fiber-reinforced thermoplastic resin molded article according to claim 1, wherein the flatness of the reinforcing fibers is 2.3-5.   The fiber-reinforced thermoplastic resin molded article according to claim 1 or 2, wherein the weight average fiber length is 1 to 10 mm.   The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 3, wherein a ratio of reinforcing fibers having a fiber length of 1 mm or more in the molded article is 30% by weight or more in all reinforcing fibers.   (B) The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 4, wherein the reinforcing fiber has an oval cross-sectional shape.   (A) The fiber reinforced thermoplastic resin molded article according to any one of claims 1 to 5, comprising at least one polyamide resin as the thermoplastic resin.   (A) The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5, comprising at least one polyester resin as the thermoplastic resin. (A) The thermoplastic resin is at least a mixed diamine composed of 0 to 50 mol% of paraxylylenediamine and 50 to 100 mol% of metaxylylenediamine, and α, ω-straight having 6 to 12 carbon atoms. The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5, comprising a polyamide resin obtained by a polycondensation reaction with a chain aliphatic dicarboxylic acid.   (A) 20 wt% or more of the thermoplastic resin is a mixed diamine composed of 0 to 50 mol% paraxylylenediamine and 50 to 100 mol% metaxylylenediamine, α having 6 to 12 carbon atoms, The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5, which is a polyamide resin obtained by a polycondensation reaction with an ω-linear aliphatic dicarboxylic acid.   (A) The fiber reinforced thermoplastic resin molded article according to any one of claims 1 to 5, comprising a polybutylene terephthalate resin and / or a polyethylene terephthalate resin as the thermoplastic resin. (A) As a thermoplastic resin, the intrinsic viscosity measured in a 1 to 1 (weight ratio) mixture of phenol and 1,1,2,2, -tetrachloroethane at 30 ° C. is at least 0.3 to 1. The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5, comprising a polybutylene terephthalate resin having a content of 2 dl / g and a titanium content of 80 ppm or less.   The roving-like reinforcing fiber is coated with a thermoplastic resin and then manufactured by an injection molding method or an extrusion molding method using pellets cut to a length of 3 mm or more. The fiber-reinforced thermoplastic resin molded article according to any one of the above.   12. The method according to claim 1, further comprising a step of injection molding or extruding pellets cut to a length of 3 mm or more after coating a roving reinforcing fiber with a thermoplastic resin. The manufacturing method of the fiber reinforced thermoplastic resin molded product as described in any one of.