KR20090087828A - Glass fiber reinforced polyamide resin composition - Google Patents

Abstract

A glass fiber-reinforced polyamide resin composition is provided to ensure excellent mechanical strength, thin-thickness moldability and surface appearance and to be suitable for parts of a portable electronic device and a personal computer housing. A glass fiber-reinforced polyamide resin composition comprises polyamide resin composition 100.0 parts by mass and glass fiber 50-150 parts by mass. The polyamide resin composition includes polyamide resin 90-99 mass % and acid-modified styrene-based elastomer 1-10 mass %. The polyamide resin comprises polyamide 66 resin 20-60 mass %, polyamide 12 resin 20-40 mass % and amorphous polyamide resin 20-50 mass %.

Description

Glass fiber reinforced polyamide resin composition {GLASS FIBER REINFORCED POLYAMIDE RESIN COMPOSITION}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to glass fiber reinforced polyamide resin compositions and molded articles. More specifically, the present invention relates to glass fiber reinforced polyamides having excellent mechanical strength, thin formability, and surface appearance, and are suitable for thin portable electronic device components and personal computer housing components. It relates to a resin composition and a molded article.

Conventionally, amorphous thermoplastic resins, such as a polycarbonate resin and ABS resin, which were excellent in the surface appearance of a molded article and low bendability, have been used for the housing of portable electronic devices, such as a PDA, a mobile telephone, and a personal computer. In addition, while the electronic apparatus has become smaller and lighter in weight, resins and thin molded articles used in the housing are required, and talc, glass fibers, and the like are blended with the polycarbonate resin and the ABS resin as reinforcing materials. However, these reinforcing resin compositions have improved strength with the incorporation of reinforcing materials, but have poor fluidity, and it has been particularly difficult to form a thin and complex shape such as a housing.

Recently, a resin composition in which a liquid crystal polymer, a polyolefin resin, a polyphenylene ether resin is alloyed based on a polyamide resin or the like, and reinforced with an inorganic filler such as glass fiber has been proposed (for example, Patent Document 1). And 2). However, these resin compositions have high fluidity compared to amorphous thermoplastic resins, such as molding temperature and mold temperature, but are excellent in fluidity. It was necessary to remove and arrange the shape of the molded article.

Two methods are proposed as a method of making both fluidity improvement and the suppression of a burr compatible. Firstly, it is a method of devising the structure of a mold (for example, refer patent documents 3 and 4). In these methods, it is difficult to produce a mold, and in the case of a complicated molded article, it is difficult to provide a mechanism for suppressing burrs in the mold structure.

Second, the method of mix | blending a non-fibrous particulate inorganic filler, the method of mix | blending a spherical inorganic filler, etc. are proposed (for example, refer patent documents 5 and 6). However, these methods are effective in suppressing burrs by blocking the gap (fine clearance between cavities / cores) of the mold generating burrs with inorganic fillers, but in the case of complex shaped articles, the inorganic fillers inhibit mold transfer and deteriorate the surface appearance. There was a problem.

Prior Art Literature

[Patent Document]

[Patent Document 1] Japanese Unexamined Patent Publication No. Hei 6-240132

[Patent Document 2] Japanese Unexamined Patent Publication No. 2001-316587

[Patent Document 3] Japanese Patent Application Laid-Open No. 4-312809

[Patent Document 4] Japanese Patent Application Laid-Open No. 5-050472

[Patent Document 5] Japanese Unexamined Patent Publication No. 2006-193727

[Patent Document 6] Japanese Unexamined Patent Publication No. 2008-007753

An object of the present invention is to provide a glass fiber reinforced polyamide resin composition which is excellent in mechanical strength, thin formability, and surface appearance, and is suitable for thin portable electronic device parts and personal computer housing parts.

In addition, the resin composition of the present invention can lower the mold temperature at the time of injection molding as compared with the aromatic nylon / polyphenylene ether resin of the conventional composition, so that the fluidity of the resin can be ensured without lowering the melt viscosity. It can suppress occurrence.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve such a subject, the present inventors achieved the said objective by mix | blending a specific polyamide resin and an acid-modified styrene-type elastomer in the glass fiber reinforced polyamide resin composition which mix | blended glass fiber. It was found that it could, and the present invention was reached.

That is, this invention is glass reinforced polyamide resin which mix | blends 50-150 mass parts of glass fibers with respect to 100 mass parts of polyamide resin compositions which consist of 90-99 mass% of polyamide resins and 1-10 mass% of acid-modified styrene-type elastomers. As a composition, polyamide resin mix | blends 20-60 mass% of polyamide 66 resin, 20-40 mass% of polyamide 12 resin, and 20-50 mass% of amorphous polyamide resin, The total amount is 100 mass% It is providing the glass fiber reinforced polyamide resin composition characterized by the above-mentioned.

According to the present invention, in the glass fiber reinforced polyamide resin composition, by using a polyamide 66 resin, a polyamide 12 resin, and an amorphous polyamide resin as the polyamide resin, an acid-modified styrene elastomer is blended at a specific ratio, It is possible to provide a resin composition having high mechanical strength and suppressing the generation of burrs at the time of molding even in a thin molded article, and having an excellent surface appearance.

The present invention is a resin composition comprising a polyamide 66 resin, a crystalline polyamide selected from a polyamide 12 resin, an amorphous polyamide, an acid-modified styrene elastomer, and glass fibers.

Crystalline polyamide as used in the present invention refers to a polyamide which exhibits a heat of fusion of crystals of 1 cal / g or more when measured at a temperature increase rate of 20 ° C / min using a differential scanning calorimeter. In addition, amorphous polyamide refers to the polyamide which does not show the heat of fusion of fusion of 1cal / g or more when measured at the temperature increase rate of 20 degree-C / min using a differential scanning calorimeter. The melting point and glass transition temperature as used in the present invention are all measured at a temperature increase rate of 20 ° C./minute using a differential scanning calorimeter, and thus, as a peak temperature of endotherm of each crystal melting and a transition temperature of specific heat, It means the temperature calculated | required by.

The polyamide 66 resin in the present invention is obtained by a method of polymerizing hexamethylenediamine and adipic acid by equimolar mixing, or by polymerizing a pair of these salts, having crystallinity, and having a melting point of 255 to 265 ° C. Phosphorus polyamide.

The polyamide 66 resin used by this invention shall handle only the polyamide 66 resin which shows the heat of fusion of crystal | crystallization more than 1 cal / g, when measured at the temperature increase rate of 20 degree-C / min using a differential scanning calorimeter. Currently known polyamide 66 resins are only crystalline polyamide 66 resins having a heat of fusion of 1 cal / g or more, but if measured at a temperature increase rate of 20 ° C / min using a differential scanning calorimeter over the future, When polyamide 66 resins having no heat of fusion of 1 cal / g or more have been developed, they are to be treated as amorphous polyamides defined in the present invention.

Although the relative viscosity of the polyamide 66 resin used for this invention is not specifically limited, The relative viscosity measured on the conditions of 25 degreeC and the density | concentration of 1 g / dl using 96 weight% concentrated sulfuric acid as a solvent is a range of 1.5-4.0. Is preferably. If the relative viscosity is less than 1.5, the low viscosity makes the brittleness after melt kneading difficult, and the desired physical properties are not obtained in the composition. Moreover, when larger than 4.0, since the fluidity | liquidity at the time of shaping | molding process is bad because of high viscosity, sufficient injection pressure is not applied, and performance as a component is not acquired.

As a commercial item, the polyamide 66 resin which can be used for this invention is a polyamide 66 resin (A125 by Unitica; relative viscosity 2.8; melting | fusing point 260 degreeC, Zytel 101L by Dupont Corporation; relative viscosity 2.8; melting | fusing point 260 degreeC, Asahi Chemical Co., Ltd.). Leona 1300, relative viscosity 2.7, melting | fusing point 260 degreeC) etc. can be used.

The heat of fusion of such polyamide 66 resin is 10 to 25 cal / g.

As for this polyamide 66 resin, 20-60 mass% is preferable with respect to 100 mass% of polyamide resins. If it is less than 20 mass%, mechanical strength will fall, and if it is 60 mass% or more, the surface glossiness of a molded object will become low, Furthermore, since generation | occurrence | production of burr becomes remarkable, it is unpreferable.

The polyamide 12 resin in the present invention can be obtained by polymerizing 12-aminododecaneic acid or ω-laurolactam to a raw material, having crystallinity, and polyamide having a melting point of 170 to 180 ° C.

Polyamide 12 resin used by this invention shall handle only the polyamide 12 resin which shows the heat of fusion of crystal | crystallization more than 1cal / g, when measured by the temperature increase rate of 20 degree-C / min using a differential scanning calorimeter. Currently known polyamide 12 resins are only crystalline polyamide 12 resins having a heat of fusion of 1 cal / g or more, but if measured at a temperature increase rate of 20 ° C / min using a differential scanning calorimeter over the future, When polyamide 12 resins having no heat of fusion of 1 cal / g or more have been developed, they are to be treated as amorphous polyamides defined in the present invention.

Although the relative viscosity of the polyamide 12 resin used for this invention is not specifically limited, The relative viscosity of 1.6-2.5 measured on the conditions which temperature is 25 degreeC and the density | concentration is 1 g / dl using 96 mass% concentrated sulfuric acid as a solvent. It is preferable that it is a range. If the relative viscosity is less than 1.6, burrs tend to occur in the molded article due to low viscosity. Moreover, when larger than 2.5, since the fluidity | liquidity at the time of shaping | molding process is bad because of high viscosity, sufficient injection pressure is not applied, and performance as a component is not acquired.

As a commercial item, the polyamide 12 resin which can be used for this invention can use polyamide 12 resin (AESN by Alchema; relative viscosity 2.3; melting | fusing point 176 degreeC) etc., for example. The heat of fusion of such polyamide 12 resin is 5 to 20 cal / g.

As for this polyamide 12 resin, 20-40 mass% is preferable with respect to 100 mass% of polyamide resins. When it is less than 20 mass%, a burr will generate | occur | produce easily in the obtained molded article, and when it is more than 40 mass%, the mechanical strength of the obtained molded article will become low and it is unpreferable.

As the amorphous polyamide resin in the present invention, a polyamide obtained by polycondensation such as a lactam of three or more rings or a polymerizable ω-aminocarboxylic acid, a diamine and a dicarboxylic acid can be used, and the glass does not have crystallinity. It is polyamide which has a transition temperature of 100 degreeC or more. The production of such amorphous polyamides is well known and conventional methods may be used.

Specific examples of the monomer constituting the amorphous polyamide resin include lactams such as ε-caprolactam and ω-laurolactam, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecaneic acid, and p- Aminocarboxylic acids such as aminobenzoic acid, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4 / 2,4,4-trimethylhexamethylenediamine, 5 -Methylnonamethylenediamine, m-xylenediamine, p-xylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, bis (4 -Aminocyclohexyl) methane, bis (3-aminocyclohexyl) methane, 3-aminocyclohexyl-4-aminocyclohexylmethane, 1-amino-3-aminomethyl-3,5,5-trimethyl Cyclohexane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, Dicarboxylic acids such as diamines such as bis (aminopropyl) piperazine and bis (aminoethyl) piperazine, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecane diacid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid There is Liu.

Examples of the combination of the monomers include polycondensates of tetramethylenediamine and adipic acid, polycondensates of hexamethylenediamine, adipic acid and terephthalic acid, and polycondensates of ε-caprolactam, hexamethylenediamine and terephthalic acid. These have crystallinity and are not suitable as the polyamide used in the present invention. Other combinations include polycondensates of hexamethylenediamine, bis (3-methyl-4-aminocyclohexyl) methane, terephthalic acid and isophthalic acid, polycondensates of hexamethylenediamine, terephthalic acid and isophthalic acid, and epsilon -caprolactam There are polycondensates of m-xylylenediamine and isophthalic acid, and polycondensates of 2,2,4 / 2,4,4-trimethylhexamethylenediamine and terephthalic acid, which have amorphous properties and are the secrets used in the present invention. It is suitable as a qualitative polyamide resin.

Preferable specific examples of the amorphous polyamide resin include polycondensates of isophthalic acid / terephthalic acid / hexamethylenediamine / bis (3-methyl-4-aminocyclohexyl) methane, terephthalic acid / 2,2,4-trimethylhexamethylene Polycondensate of diamine / 2,4,4-trimethylhexamethylenediamine, polycondensate of isophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam, isophthalic acid / terephthalic acid / Polycondensate of hexamethylenediamine, isophthalic acid / 2,2,4-trimethylpolycondensate of hexamethylenediamine / 2,4,4-trimethylhexamethylenediamine, isophthalic acid / terephthalic acid / 2,2,4-tri Polycondensates of methylhexamethylenediamine / 2,4,4-trimethylhexamethylenediamine, polycondensates of isophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam, etc. Can be. The benzene ring of the terephthalic acid component and / or the isophthalic acid component is also substituted with an alkyl group or a halogen atom. Moreover, these amorphous polyamide resins can also be used together 2 or more types. Preferably, polycondensates of isophthalic acid / terephthalic acid / hexamethylenediamine / bis (3-methyl-4-aminocyclohexyl) methane, or terephthalic acid / 2,2,4-trimethylhexamethylenediamine / 2, Polycondensates of 4,4-trimethylhexamethylenediamine or polycondensates of isophthalic acid / terephthalic acid / hexamethylenediamine / bis (3-methyl-4-aminocyclohexyl) methane and terephthalic acid / 2,2,4- Mixtures of polycondensates of trimethylhexamethylenediamine / 2,4,4-trimethylhexamethylenediamine are used.

As amorphous polyamide resin of this invention, as long as glass transition temperature is 100 degreeC or more, any monomer composition may be sufficient besides the combination of the said monomer.

Moreover, as a most preferable compounding example of this monomer, 40-50 mol of hexamethylenediamine in the case of the polycondensation product of hexamethylenediamine, the bis (3-methyl-4-aminocyclohexyl) methane, terephthalic acid, and isophthalic acid. %, Bis (3-methyl-4-aminocyclohexyl) methane 0-10 mol%, terephthalic acid 0-30 mol%, 20-50 mol% of isophthalic acid can be adjusted suitably.

The relative viscosity of the amorphous polyamide resin used in the present invention is not particularly limited, but the relative viscosity measured at a temperature of 25 ° C. and a concentration of 1 g / dl using 96 mass% concentrated sulfuric acid as a solvent is 1.5 to 2.8. It is preferable that it is a range. If the relative viscosity is less than 1.5, the mechanical strength is lowered. On the contrary, if the relative viscosity is higher than 2.8, the melt viscosity is increased and the moldability is deteriorated.

As for this amorphous polyamide resin, 20-50 mass% is preferable with respect to 100 mass% of polyamide resins. When less than 20 mass%, surface appearance worsens, and when it is more than 50 mass%, the fluidity | liquidity of resin will worsen at the time of shaping | molding, and a thin molded object cannot be obtained in thickness.

In the resin composition of the present invention, as a reason for using the crystalline polyamide composed of polyamide 66 resin and polyamide 12 resin and the amorphous polyamide in combination, first, glass fibers are blended using polyamide 66 resin as a matrix. In one resin composition, the crystallization rate is too fast and rapidly cooled in the mold, causing volume shrinkage, floating of glass fibers on the surface of the molded article, resulting in unevenness, resulting in poor surface appearance. On the other hand, in the resin composition which mix | blended glass fiber using polyamide 66 resin and an amorphous polyamide resin, amorphous polyamide resin inhibits the crystallinity of polyamide 66 resin, and surface appearance becomes favorable. On the other hand, amorphous polyamide resins have poor fluidity at the time of thermoplasticity, and cannot produce a neat molded body in thin thickness.

Here, in the case of using polyamide 6 (crystalline) instead of polyamide 66, not only the mechanical properties are lowered, but also the burr characteristics of the molded article obtained by molding are deteriorated, and in particular, in the thin molded article of the present invention, polyamide 6 The resin does not have to be blended. In addition, when polyamide 6 (crystalline) is used instead of polyamide 12, the tensile fracture elongation of the molded object obtained falls, generation | occurrence | production of burr becomes remarkable and surface gloss worsens.

In the present invention, by appropriately blending three components of polyamide 66 resin, amorphous polyamide resin, and polyamide 12 resin as the polyamide resin to be blended, the two-component system of polyamide 66 resin and amorphous polyamide resin, After injection molding, it is possible to lengthen the cooling completion time of the resin composition to be cooled and solidified by the mold, that is, the time to reach the temperature crystallization temperature of the molded article, during which time sufficient fluidity to the resin is ensured. In addition, it is possible to suppress excessive volume shrinkage by cooling with sufficient time, and to suppress warpage of a molded article due to the floating and shrinking anisotropy of glass fiber, and the occurrence of burr is small, so that not only surface appearance but also excellent dimensional stability are achieved. A molded article can be obtained. On the other hand, the floating of glass fiber is the state in which the glass fiber of the glass fiber mix | blended in the resin composition, especially the glass fiber of the part near the surface of a molded article floated only on the surface by the volume shrinkage of the surrounding resin part (glass fiber part) This becomes a convex part).

As the acid-modified styrene-based elastomer used in the present invention, a hydrogenated styrene butadiene copolymer or a hydrogenated styrene isoprene copolymer can be used, and they are random copolymers, block copolymers, Any of a graft copolymer or the like may be used, and a polymerizable monomer having a functional group is introduced into a part of the polymer.

As a polymerizable monomer which has a functional group used here, aliphatic carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, aliphatic carboxylic acids, such as maleic anhydride, itaconic anhydride, a citraconic acid anhydride, phthalic anhydride, trimelli anhydride Hydroxyl group-containing substances, such as aromatic carboxylic anhydrides such as acetic acid, hydroxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, and lactone-modified hydroxyethyl (meth) acrylate, and glycidyl (meth) acrylate And epoxy group-containing vinyls such as methylglycidyl (meth) acrylate, and the like, and two or more kinds thereof may be used in combination. There is no problem even if some include those which do not react with these polymerizable monomers.

Among these acid-modified styrene-based elastomers, acid-modified styrene-ethylene-butylene-styrene block copolymers (SEBS) are suitably used. If it is not hydrogenated, the styrene-based elastomer may crosslink with the polyamide resin, and if the crosslinking reaction is carried out, the fluidity of the resin may be deteriorated, and the thinner resin may be less likely to be filled.

An acid-modified styrene-based elastomer is preferably used that the acid value of the acid-modified degree of from 1 to 15㎎ CH ₃ Na / g and it is more preferable to use an acid value of from 2 to 10㎎ CH ₃ Na / g. The use of an acid-modified styrene-based elastomer having an acid value of less than ₁ mg CH ₃ Na / g is not preferable because of poor compatibility with polyamide and a decrease in mechanical strength. In addition, the use of an acid-modified styrene-based elastomer having an acid value of more than 15 mg CH ₃ Na / g is not preferable because the melt viscosity of the resin composition becomes too high, which impairs moldability.

In addition, in order to improve the compatibility with polyamide, the acid-modified styrene-based elastomer preferably has a melt flow rate (hereinafter referred to as "MFR") measured at 230 ° C x 2.16 kgf of 3 to 10 g / 10 min. More preferably 9 g / 10 min. If the MFR is less than 3 g / 10 min, the fluidity at the time of melting is poor, and if the MFR is more than 10 g / 10 min, the fluidity at the time of melting is too good, and the dispersion is uniformly dispersed with the polyamide resin. It doesn't work. MFR is an index of the molecular weight of an acid-modified styrene elastomer, and the number average molecular weight whose MFR is 3-10 g / 10min is about 1-200,000 (kPa).

In addition, when an acid-modified styrene-based elastomer was used or an unmodified styrene-ethylene-butylene-styrene block copolymer or a polyolefin-based elastomer was used instead of the acid-modified styrene-based elastomer, the compatibility with polyamide It is unpreferable because it worsens and mechanical strength falls.

The acid-modified styrene-based elastomer is an acid-modified conventional styrene-based elastomer, and with respect to the styrene-based elastomer obtained by copolymerizing each block unit of styrene, ethylene and butadiene, at least in the molecular chain using maleic anhydride or the like It can be manufactured by introducing one carboxyl group, and as a commercially available product, an acid-modified styrene-ethylene butadiene-styrene block copolymer (Taftech M1911 manufactured by Asahi Kasei Chemical Co., Ltd .: acid value 2 mg CH ₃ Na / g, MFR 4.5 g / 10min, Taftech M1913 manufactured by Asahi Kasei Chemical Co., Ltd .: acid value 10 mg CH ₃ Na / g, MFR 5.0 g / 10 min, Taftech M1943 manufactured by Asahi Kasei Chemical Co., Ltd .: acid value 10 mg CH ₃ Na / g, MFR 80 g / 10min) Etc. can be obtained.

As for this acid-modified styrene elastomer, 1-10 mass% is preferable in 100 mass% of polyamide resin compositions. When less than 1 mass%, the tensile breaking elongation of the obtained molded article becomes low, and when more than 10 mass%, since fluidity deteriorates, it becomes difficult to fill resin precisely in thin thickness, and it is unpreferable.

Although the glass fiber in this invention may use what has a round cross section, as a long diameter, it is in the range of 10-50 micrometers as a long diameter, and 5-20 micrometers as a short diameter, and a long diameter It is preferable to use flat glass fibers having a flat cross-sectional shape having a ratio of 1.5 to 10 shorter diameters. Especially, in order to reduce the curvature of the molded article which is peculiar to glass fiber reinforced polyamide resin composition, the thing of the ratio of 1.5-10 of the long diameter / short diameter of a flat cross-sectional shape can be used effectively. More preferably, it is 2.0-6.0. If the long diameter / short diameter ratio is 1.5 or less, the effect of reducing warpage is insufficient, and the long diameter / short diameter ratio of 10 or more is difficult to manufacture the glass fiber itself. As a flat cross-sectional shape, shapes, such as circumferential shape, eyebrow shape, oval shape, rectangle, etc. other than oval, can be selected, but if it is effective in suppressing the bending of the thin molded article which is an effect of this invention, it is not limited to these cross-sectional shapes. .

The glass fiber can be selected from long fiber type roving, short fiber type chopped strand, milled fiber and the like. If it is a long fiber type, since it is a continuous fiber in which roving is wound, it is necessary to make a long fiber resin pellet (a) by impregnating a small amount of polyamide resin melted in a roving once. These long-fiber resin pellets are polyamide resin compositions prepared separately from polyamide resins and elastomers (however, since the long-fiber resin pellets (a) are already impregnated with polyamide resins, the polyamide resin of the final polyamide resin composition) From the blending amount, the resin pellet (b) consisting of the amount of polyamide resin required for impregnation) is mixed at the time of molding, injection molding and extrusion molding to form a molded article having excellent mechanical properties utilizing the length of the long fiber glass fibers to be blended. Can be. In that case, the long fiber resin pellet to be used is what is normally about 3-15 mm in length. In long fiber resin pellets, since long fiber glass fiber exists in the same length, when the length of a long fiber resin pellet exceeds 15 mm, defects of a long fiber resin pellet are easy to produce at the time of shaping | molding process, and When the length of a fiber resin pellet is less than 3 mm, when forming a molded object, it cannot be made into the molded object with sufficient mechanical characteristics. If it is necessary to blend shorter glass fibers, it is suitable to use chopped strands that have been shortened in advance. When using a chopped strand, it is preferable that it is a glass fiber whose length is 3-6 mm, and it is more preferable that it is 4-5 mm in length. In addition, when preparing a long fiber resin pellet, it is set as the polyamide resin composition which compounded the long fiber type and the short fiber type glass fiber by mix | blending the chopped strand of the glass fiber adjusted suitably with respect to the resin pellet (b). It is also possible. The glass fiber may use what surface-treated with silane coupling agents, such as an epoxy system, an aminosilane system, and an isocyanate system.

As thickness of the fiber to be used, in order to acquire the mechanical strength as a glass fiber original reinforcement material, what is 3-20 micrometers in thickness shall be used. If the thickness is too thick, toughness of the glass fiber will not be obtained, and too thin glass fiber will not only be difficult to manufacture, but also cause problems such as a lack of reinforcing effect as a reinforcing material.

As for the compounding quantity of this glass fiber, 50-150 mass parts is preferable with respect to 100 mass parts of polyamide resin compositions. If it is less than 50 mass parts, the mechanical strength of a molded article will be low, and if it is 150 mass parts or more, the fluidity | liquidity of resin will be bad, and in the case of thin thickness, it is difficult to obtain the molded object with high dimensional precision.

Moreover, a pigment, a heat stabilizer, antioxidant, a weathering agent, a flame retardant, a plasticizer, a mold release agent, another reinforcing material, etc. can also be added to the resin composition of this invention. When adding, the addition amount will not be specifically limited unless the effect of this invention is largely impaired, but what is necessary is just to use about 0.01-20 mass parts with respect to 100 mass parts of glass fiber reinforced polyamide resins normally.

Such thermal stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds and copper compounds.

As the weathering agent, general benzophenones and benzotriazoles are used.

As a flame retardant, a general phosphorus flame retardant or a halogen flame retardant is used.

Examples of the reinforcing material include clay, talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, aluminum hydroxide, calcium hydroxide, Barium sulfate, potassium alum, sodium alum, iron alum, glass balloon, carbon black, zinc oxide, antimony trioxide, boric acid, borax, zinc borate, zeolite, hydrotalcide, metal fiber, metal whisker, ceramic whisker, potassium titanate whisker Boron nitride, mica, graphite, glass fibers, carbon fibers and the like.

Generally, the resin composition of this invention can be manufactured by melt-kneading using the extruder which has a single screw or a twin screw. The polyamide resin and the elastomer component are collectively added, the glass fiber is added and extruded from the middle using a side feeder, and then extruded as a strand and cut by a pelletizer to obtain a resin pellet.

Further, only the polyamide component is added in a batch to obtain a resin pellet, and the pellet is dried, the pellet and the elastomer resin are added in a batch, melt-kneaded, and then glass fibers are added by a side feeder to form the resin pellet. You can also get

The extrusion temperature can be determined by the melting point of the polyamide 66 resin having the highest melting point among the resins to be blended. It is necessary to melt the resin used as a raw material sufficiently, but if the extrusion temperature is raised more than necessary, the effect of the present invention cannot be sufficiently exhibited. In this invention, it is preferable to perform the extrusion temperature which melt-kneads in the temperature range within melting | fusing point +60 degreeC of polyamide 66, and is 280 degreeC-320 degreeC. If the melting point of polyamide 66 is exceeded, the decomposition of other resins is promoted, leading to coloration and deterioration of mechanical properties.

Although screw rotation at the time of kneading changes with the screw diameter of the extruder to be used, For example, when using the extruder with a screw diameter of 37 mm, it is preferable to carry out in 100-400 rpm. If it is less than 100 rpm, the kneading becomes insufficient and a sufficient discharge amount cannot be obtained. When it exceeds 400 rpm, the kneading becomes excessive and the glass fibers are unnecessarily shortened, so that the compatibility of the resin composition proceeds excessively, burrs are likely to occur, and sufficient mechanical properties are not obtained.

In addition, in blending the polyamide resin and the glass fiber, it is important to balance the extrusion temperature, screw rotation, and discharge amount. If the extrusion temperature is too high, the polyamide resin deteriorates and mechanical properties deteriorate. When the screw rotation becomes too low, the mechanical properties are worse because the extrusion torque is increased and the glass fibers are shortened. As an example of preferable conditions, when the kneading machine with a screw diameter of 37 mm is used, extrusion temperature 280 degreeC, screw rotation 250 rpm, and discharge amount 25 kg / h are optimal.

The resin composition of the present invention has a high mechanical strength, and even if there is a molded part having a thin molded article, particularly, a thickness of 0.1 to 5 mm and thinner to 0.05 to 2 mm, generation of burrs can be suppressed during molding, and the surface Molded articles having excellent appearance can be obtained, and housings of electric and electronic devices such as mobile terminals such as PDAs and mobile phones, housings such as personal computers, OA devices, batteries, or power tools, their internal parts, and exterior plates for automobiles It can be used for door panels, door mirrors, door mirror stays, bicycles, scooters, boat cowls and lighting equipment. In particular, the composition of the present invention is useful for electronic housings that require thinning of mobile terminals, personal computers, OA devices and the like.

EXAMPLE

Although an Example and a comparative example are shown to the following and this invention is concretely demonstrated to it, this invention is not limited to this. In addition, the physical property measurement of the raw material and molded article in an Example and a comparative example was performed as follows.

(Reference Example 1): Amorphous Polyamide (A-5)

10 kg of a raw material having a ratio of 45 mol% of isophthalic acid, 5 mol% of terephthalic acid, 45 mol% of hexamethylenediamine, and 5 mol% of bis- (4-amino-3-methylcyclohexyl) methane together with 8 kg of pure water Into the reactor, the air in the reactor was purged with nitrogen several times. After raising temperature to 90 degreeC and making it react for about 5 hours, reaction temperature was gradually raised to 280 degreeC over 10 hours, stirring, stirring under pressure (18 bar). Subsequently, the pressure was released to lower the pressure to atmospheric pressure, and then polymerization was further performed at the same temperature for 6 hours. After completion | finish of reaction, it removed from the reaction tank and cut | disconnected to obtain pellet. The relative viscosity (same method as the above) of the obtained pellet was 1.90. Moreover, the glass transition temperature was 150 degreeC, and the heat of fusion was 0 cal / g. This amorphous polyamide is referred to as A-5. Polyamides of A-4 and A-6 can also be produced according to this method.

(Reference Example 2): Amorphous Polyamide (A-6)

10 kg of a raw material having a ratio of 70 mol% of isophthalic acid, 30 mol% of terephthalic acid, and 100 mol% of hexamethylenediamine was introduced into the reactor with 8 kg of pure water, and the air in the reactor was purged several times with nitrogen. After raising temperature to 90 degreeC and making it react for about 5 hours, reaction temperature was gradually raised to 280 degreeC over 10 hours, stirring, stirring under pressure (18 bar). Subsequently, the pressure was released to lower the pressure to atmospheric pressure, and then polymerization was further performed at the same temperature for 6 hours. After completion | finish of reaction, it removed from the reaction tank and cut | disconnected to obtain pellet. The relative viscosity (same method as the above) of the obtained pellet was 2.1. Moreover, the glass transition temperature was 125 degreeC, and the heat of fusion was 0 cal / g.

(1) raw material

(A) polyamide resin

Crystalline polyamide (A-1): Polyamide 66 resin (A125 manufactured by Unitica; relative viscosity 2.8, melting point of 260 ° C, heat of fusion of 18 cal / g)

Crystalline polyamide (A-2): Polyamide 12 resin (AESN manufactured by Alkema; Relative Viscosity 2.3; Melting point 176 ° C, Crystal heat of fusion 13cal / g)

Crystalline polyamide (A-3): Polyamide 6 resin (A1030BRL manufactured by Unitica; Relative viscosity 2.5; Melting point 220 ° C, Crystal heat of fusion 22cal / g)

Crystalline polyamide (A-4): polycondensate of terephthalic acid, adipic acid and hexamethylenediamine (terephthalic acid / adipic acid / hexamethylenediamine = 45/55/100 (molar ratio); relative viscosity 2.7, melting point 290 ° C) Heat of fusion 8cal / g)

Amorphous polyamide resin (A-5): polycondensate of (isophthalic acid, terephthalic acid, hexamethylenediamine and bis (3-methyl-4-aminocyclohexyl) methane (isophthalic acid / terephthalic acid / hexamethylenediamine / Bis (3-methyl-4-aminocyclohexyl) methane = 45/5/45/5 (molar ratio); relative viscosity 1.9, glass transition temperature 150 ° C, heat of fusion of crystals 0cal / g)

Amorphous polyamide resin (A-6): (polycondensate of isophthalic acid, terephthalic acid and hexamethylenediamine (isophthalic acid / terephthalic acid / hexamethylenediamine = 70/30/100 (molar ratio); relative viscosity 2.1, glass transition) Temperature 125 ℃, heat of fusion 0cal / g)

(B) acid-modified styrene-based elastomer

Elastomer (B-1): Acid-modified styrene-ethylene butadiene-styrene block copolymer (Taftech M1911 made by Asahi Kasei Chemical Co., Ltd .: acid value 2 mg CH ₃ Na / g, MFR 4.5 g / 10 min)

Elastomer (B-2): Styrene-ethylene butadiene-styrene block copolymer (Taftech H1141 made by Asahi Kasei Chemical Co., Ltd .: acid value 0 mg CH ₃ Na / g, MFR 140 g / 10 min)

(C) glass fiber

Glass fiber (C-1): Flat glass fiber with elliptical cross section with a ratio of long and short diameters of 4 (CSG3PA820S manufactured by Nittobo Corporation; 28 µm long, 7 µm short, 3 mm fiber length, with silane-based surface treatment)

Glass fiber (C-2): Glass fiber with a circular cross section (03JAFT69 by Asahi Fiber Glass, Inc .; average fiber diameter 10 micrometers, fiber length 3mm)

(2) Measurement of physical properties of molded products

a) bending strength, bending elastic modulus and elongation at break

The test piece was shape | molded at the resin temperature of 280 degreeC, and die temperature of 80 degreeC with the injection machine made from a Panax (alpha-100iA), and the bending characteristic was measured according to ASTM D790, and the tensile characteristic according to ASTM D-639. Bending strength of 280 MPa or more, bending elastic modulus of 13 GPa or more, and tensile elongation at break of 1% or more were regarded as pass.

b) formability

The molded product of the shape shown in FIG. 1 of thickness 0.4mm, width 40mm, and length 70mm was shape | molded by the injection molding machine ((alpha) -100iA) made by a Panax, at resin temperature of 280 degreeC, mold temperature of 80 degreeC, and maximum injection pressure of 120 MPa. . The moldability was evaluated as follows from the filled state of resin. ○ The above was regarded as passing.

(Double-circle): Resin is filled in the balance over the whole molded object.

(Circle): Although the molded object is filled with resin, the weld part can be confirmed.

(Triangle | delta): Although the molded object is filled with resin, some shrinkage defects are recognized by some parts, such as a rib back part.

X: The unfilled part of resin is seen in a part of molded object.

c) burr

An injection molding machine (α-100iA) made by Panax is used to mold a molded article having the shape shown in FIG. 1 having a thickness of 0.4 mm, a width of 40 mm, and a length of 70 mm at a resin temperature of 280 ° C. and a mold temperature of 80 ° C. The length of the bur was measured by observing under a microscope. Less than 50 micrometers was made into the pass. Although the measurement of the length of a burr usually evaluates using test pieces, such as a dumbbell, in this application, it evaluated using the test mold which imitated the shape of an actual molded article (for example, the liquid crystal frame of a mobile telephone). Therefore, burr evaluation in this application is performed more strictly compared with the test piece of thickness 3-4mm like a dumbbell.

d) surface gloss

In the injection molding machine (alpha-100iA) made from a Panax, the molded object of the shape shown in FIG. 1 of thickness 0.4mm, width 40mm, and length 70mm is shape | molded by resin temperature 280 degreeC and die temperature 80 degreeC, and the surface glossiness measuring part By visual observation, the floating state of the glass was examined. Although the evaluation method is shown below, (circle) or more were made into the pass.

(Double-circle): The floating of glass is not seen at all.

(Circle): Floating of glass is not seen, but reflection of light is not enough.

(Triangle | delta): The floating of glass is seen slightly.

X: The floating of glass is observed, and the reflection of light is also bad.

(Production example)

(A-7) Preparation of Polyamide Resin

40 mass% of polyamide 66 resin, 25 mass% of polyamide 12 resin, and 35 mass% of amorphous polyamide resin were mixed with TEM37BS by Toshiba Machine Co., Ltd. by extrusion temperature 280 degreeC, screw rotation speed 250rpm, and stirring torque 60%. The obtained polyamide resin (A-7) was dried and then subjected to subsequent tests.

(A-8) to (A-17) Preparation of Polyamide Resin

According to the formulation of Table 1, it produced like (A-7).

(A-18) to (A-27) Preparation of Polyamide Resin

According to the formulation of Table 2, it produced like (A-7).

Preparation of (A-28) to (A-35) polyamide resin

According to the formulation of Table 3, it produced like (A-7).

(Example 1)

As shown in Table 4, 97 mass% of polyamide resin (A-7) and 3 mass% of elastomer (B-1) were thrown in from the base of the extruder 37BS by Toshiba Machine Co., Ltd., and 100 mass parts of these resins. 100 mass parts of glass fibers (C-1) were thrown in from the side, it mixed at the extrusion temperature of 280 degreeC, and the screw speed of 250 rpm, and the glass fiber reinforced polyamide resin composition pellet was obtained. After drying, the obtained pellets evaluated each property by the method shown above. Bending strength, bending elastic modulus, elongation at break, formability, burr length, and surface gloss were all satisfied.

(Examples 2 to 16)

Operation similar to Example 1 was performed and the glass fiber reinforced polyamide resin composition pellets were obtained. After drying, the obtained pellets evaluated each property by the method shown above. Bending strength, bending elastic modulus, elongation at break, formability, burr length, and surface gloss were all satisfied.

(Comparative Examples 1 to 23)

Operation similar to Example 1 was performed and the glass fiber reinforced polyamide resin composition pellets were obtained. After drying, the obtained pellets evaluated each property by the method shown above. Since Comparative Examples 1 to 24 were outside the scope of the present invention, the standard did not satisfy any of bending strength, bending elastic modulus, tensile elongation at break, formability, burr length, and surface gloss.

The results of Examples 1 to 16 and Comparative Examples 1 to 23 are shown in Tables 4 to 8, respectively.

In Table 4, as compared with Comparative Example 1, Example 1, and Example 2, it turns out that bending strength and bending elastic modulus also become high, as the ratio of the polyamide 66 mix | blended with the polyamide resin to be used becomes high. In Comparative Example 1 in which the blend of polyamide 66 was less than 20% by mass with respect to 100% by mass of polyamide resin, the bending strength and the bending elastic modulus did not satisfy the predetermined criteria, and the moldability was also poor.

In Table 4, in comparison with Example 3, Comparative Example 2, and Comparative Example 3, as the ratio of polyamide 66 to be blended with the polyamide resin to be used increases, the bending strength and the bending elastic modulus also increase, while the surface gloss of the resin molded article is increased. This was degraded. The surface gloss did not satisfy | fill the predetermined | prescribed criterion in the comparative example 2 and the comparative example 3 in which the compounding of polyamide 66 exceeds 60 mass% with respect to 100 mass% of polyamide resin. In addition, burr generation was remarkable, and the burr length exceeded the reference length.

In Table 4, compared with Comparative Example 4, Example 4, and Example 5, as the ratio of polyamide 12 to be blended with the polyamide resin to be used was increased, generation of burrs was suppressed when injection molding the resin molded article. In the comparative example 4 in which the compounding of polyamide 12 became less than 20 mass% with respect to 100 mass% of polyamide resins, generation | occurrence | production of burr was remarkable, burr length exceeded the reference length, and moldability was also bad.

In Table 5, in comparison with Example 6 and Comparative Example 5, as the ratio of polyamide 12 to be blended with the polyamide resin to be used increases, the bending strength and the bending elastic modulus decrease. In Comparative Example 5 in which the blend of polyamide 12 exceeded 40% by mass with respect to 100% by mass of polyamide resin, the bending strength and the bending elastic modulus did not satisfy the predetermined criteria.

In Table 5, in comparison with Comparative Example 6, Example 7, Example 8, and Comparative Example 7, as the ratio of amorphous polyamide to be blended to the polyamide resin to be used increases, the surface gloss of the obtained molded article is improved. The moldability was reduced. In Comparative Example 6 in which the formulation of the amorphous polyamide was less than 20% by mass with respect to 100% by mass of the polyamide resin, the surface gloss of the molded article did not satisfy the criteria.

In Table 6, compared with Example 11, Example 12, and Comparative Example 8, as the ratio of the amorphous polyamide to be blended with the polyamide resin to be used increases, the moldability was lowered. The surface gloss of the resin molded article was all favorable. In Comparative Example 6 in which the formulation of the amorphous polyamide exceeded 50% by mass with respect to 100% by mass of the polyamide resin, the moldability of the molded article did not satisfy the criteria.

In Table 6, in Comparative Example 9, the blending of polyamide 66 with respect to 100% by mass of the polyamide resin exceeded the predetermined blending amount, while neither the polyamide 12 nor the amorphous polyamide satisfied the blended blending amount. For this reason, generation | occurrence | production of the burr of the obtained resin molded article was remarkable, and surface gloss fell large.

In Table 6, in Comparative Example 10, the blending of polyamide 66 with respect to 100% by mass of the polyamide resin did not satisfy the predetermined blending amount, whereas the polyamide 12 exceeded the predetermined blending amount. For this reason, the bending strength and bending elastic modulus of the obtained molded article fell large.

In Table 6, in Comparative Example 11, polyamide 66 and polyamide 12 did not satisfy the predetermined compounding amount with respect to 100% by mass of polyamide resin, whereas amorphous polyamide exceeded the predetermined compounding amount. For this reason, the bending strength and bending elastic modulus of the obtained molded article were greatly reduced, and the moldability was also reduced.

In Table 6, since the comparative example 12 used polyamide 6 instead of the polyamide 66, the bending strength and the bending elastic modulus of the obtained molded article were greatly reduced. In addition, burr generation was remarkable, and the burr length exceeded the reference length.

In Table 6, Comparative Example 13 is a polycrystalline condensate of terephthalic acid, adipic acid and hexamethylenediamine (terephthalic acid / adipic acid / hexamethylenediamine = 45/55/100 (molar ratio) instead of amorphous polyamide). Because of this, the moldability was bad, and the surface gloss of the obtained molded article was greatly reduced.

In Table 6, Example 13 used glass fibers having a circular cross section instead of flat glass fibers. Although it was slightly inferior in moldability compared with the case of using flat glass fibers, all of the bending strength, bending elastic modulus, tensile elongation at break, formability, burr length, and surface gloss were satisfied.

In Table 7, Examples 14-16 used amorphous polyamide (A-6) instead of amorphous polyamide (A-5). Bending strength, bending elastic modulus, elongation at break, formability, burr length, and surface gloss were all satisfied.

In Table 7, Example 17 was performed like Example 9 except having mix | blended 8 mass% of elastomers with respect to 100 mass% of polyamide resin compositions. As the proportion of the elastomer increased, the bending strength and the bending elastic modulus decreased, and the surface gloss of the molded article tended to improve. Bending strength, bending elastic modulus, elongation at break, formability, burr length, and surface gloss were all satisfied.

In Table 7, Comparative Examples 14-17 were carried out similarly to Example 9, with respect to 100 mass% of polyamide resin compositions except the compounding quantity of an elastomer being a compounding quantity out of a predetermined range. In Comparative Examples 14 and 15, since the blending of the elastomer did not satisfy the predetermined amount, the tensile fracture elongation did not satisfy the criterion, and the surface gloss was also lowered. On the other hand, in the comparative examples 16 and 17, since the compounding of the elastomer exceeded predetermined amount, moldability fell.

In Table 8, the comparative example 18 was performed like Example 9 except using the elastomer (B-2) instead of the elastomer (B-1). Since elastomers other than the acid-modified styrene-based elastomer were used, the mechanical strength was lowered, the moldability was worsened, and the surface gloss of the molded article was lowered.

In Table 8, Comparative Examples 19 to 22 were carried out in the same manner as in Example 9, except that the blending of the glass fibers was made into a blending amount outside a predetermined range with respect to 100% by mass of the polyamide resin composition. In Comparative Examples 19 and 20, since the blending of the glass fibers was lower than the predetermined amount, the bending strength and the bending elastic modulus did not satisfy the criteria. On the other hand, in the comparative examples 21 and 22, since the compounding of the glass fiber exceeded predetermined amount, moldability worsened and the surface gloss of the molded article obtained fell.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view (surface) of the molded article which evaluated the presence or absence of burr generation and surface glossiness of this invention.

It is a perspective view (back surface) of the molded article which evaluated the presence or absence of burr generation and surface glossiness of this invention.

Explanation of symbols for the main parts of the drawings

1: gate position 2: burr evaluation section

3: surface gloss evaluation unit

Claims (4)

As a glass-reinforced polyamide resin composition which mix | blends 50-150 mass parts of glass fibers with respect to 100 mass parts of polyamide resin compositions which consist of 90-99 mass% of polyamide resins, and 1-10 mass% of acid-modified styrene-type elastomers, Resin consists of 20-20 mass% of polyamide 66 resin, 20-40 mass% of polyamide 12 resin, and 20-50 mass% of amorphous polyamide resin, The total amount is 100 mass%, It is characterized by the above-mentioned. Glass fiber reinforced polyamide resin composition. The method of claim 1, A glass fiber reinforced polyamide resin composition, wherein the glass fiber is a flat glass fiber having a flat cross section having a long diameter / short diameter ratio of 1.5 to 10. The method according to claim 1 or 2, The acid-modified styrene-based elastomer is an acid-modified styrene-ethylene-butylene-styrene block copolymer (SEBS), The glass fiber reinforced polyamide resin composition characterized by the above-mentioned. An electronics housing comprising the glass fiber reinforced polyamide resin composition according to any one of claims 1 to 3.

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