WO2011115031A1

WO2011115031A1 - Polyamide resin composition for injection moulding

Info

Publication number: WO2011115031A1
Application number: PCT/JP2011/055884
Authority: WO
Inventors: 泰人藤井; 信宏吉村
Original assignee: 東洋紡績株式会社
Priority date: 2010-03-15
Filing date: 2011-03-14
Publication date: 2011-09-22
Also published as: JPWO2011115031A1; JP5067506B2; TW201139556A

Abstract

Provided is a polyamide resin composition comprising an amorphous polyamide resin (A) that contains alicyclic groups but not aromatic groups, a terpene phenolic resin (B), and modified cross section glass fibres (C) that have a modified cross section with a long diameter to short diameter ratio of 1.5 to 10. The polyamide resin composition for injection moulding has (i) a surface glass transition temperature of 125-160 °C, and (ii) a melt viscosity at 285 °C of 1000-2000 Pa⋅s at a shear velocity of 12.2 sec^-1 and 100-350 Pa⋅s at a shear velocity of 1216 sec^-1. The polyamide resin composition is exceptionally stable during production, has low variation in mechanical strength, thin wall mouldability, dimensional stability, etc., can minimise burr development in thin wall injection moulding products, and furthermore, has excellent coating adhesion.

Description

Polyamide resin composition for injection molding

The present invention relates to a polyamide resin composition for injection molding, and in particular, it is excellent in mechanical strength, thin-wall moldability, and dimensional stability, can reduce the occurrence of burrs in injection molded products as much as possible, and is excellent in paint adhesion. It is a polyamide resin composition.

In recent years, small electronic devices such as mobile phones, portable game machines, and PDAs (Personal Digital Assistants) have been increasingly required to be thin and light, and electronic devices manufactured by injection molding to meet this demand. It is necessary to reduce the thickness of the housing. In order to achieve thinning of the electronic equipment casing, the injection molding machine must achieve high injection pressure and injection speed during injection molding, and the molding material must have mechanical strength, thin formability, dimensional stability, etc. It is done.
Amorphous resins such as polycarbonate (PC) and ABS resin have high dimensional stability and high toughness, but they have low fluidity, and when a fibrous reinforcing material is added, the fluidity is further lowered and the moldability is further improved. Since it deteriorates, the filling of the fibrous reinforcing material is limited to about 20% by weight (for example, Patent Document 1), and it has been considered that it is difficult to achieve both high rigidity by the amorphous resin and thinning of the molded product. It was.
On the other hand, crystalline polyamide resin is generally highly fluid and can maintain sufficient fluidity for thin-wall molding even when a fibrous reinforcing material is added, so crystalline polyamide resin is used for electronic device casings. It is coming.
Amorphous polyamide or polyamide 6 crystalline polyamide resin is blended with amorphous polyamide resin, and a fibrous material is highly filled with molding material (Patent Document 2) or low viscosity crystalline polyamide resin. There has been proposed a molding material in which crystalline polyamide resin and glass fiber having an irregular cross-sectional shape are blended by 40% by weight or more to improve rigidity and strength (Patent Documents 3 and 4).
However, these methods are mainly composed of crystalline polyamide resin and have a complicated composition due to the blending of various types of resins, reactive resins and compounds. There is variation in the dimensional stability and burr generation suppression effect, and there is room for improvement.

Japanese Patent Application Laid-Open No. 7-252412 JP 2004-168849 A JP 2008-163340 A JP 2009-215534 A

The present invention is intended to solve the above-mentioned problems, has a simple composition and excellent production stability, has little fluctuation in mechanical strength, thin-wall moldability, dimensional stability, etc., and generates burrs in thin-wall injection molded products. It is an object of the present invention to provide a polyamide resin composition that can reduce as much as possible and is excellent in paint adhesion.

The inventors have intensively studied to achieve both excellent thin moldability and suppression of burrs, and in order to prevent molding defects when filling the mold cavity with molten molding resin, Change the injection speed pattern of the molding resin from fast (initial) to slow (final) so that the flow front speed is constant, and the flow front speed is suitable for the molten molding resin. I found out that
In other words, high fluidity can be achieved if the melt viscosity can be lowered at a high shear rate at the initial stage when the injection speed is high (high shear rate), which is the peak of filling the mold cavity into the mold cavity. If the melt viscosity can be increased at a low shear rate at the end of a low rate (low shear rate), it is considered that the generation of burrs can be suppressed. Further, if it is amorphous, the solidification rate is slow, the restriction on the flow front speed is small, and the range of molding conditions can be widened.
Therefore, as a result of earnest research on the melt flow characteristics when the molten resin composition is filled into the mold, the amorphous polyamide resin having a specific composition, a small amount of the terpene phenol resin, and a modified cross-section glass having a modified cross section. When the melt viscosity characteristics are set in a specific range by combining fibers, even if the glass fiber content exceeds 40% by mass, the melt fluidity can be increased, thin molding is easy, and The inventors have found that generation can be suppressed and have reached the present invention.

That is, the present invention
(1) Amorphous polyamide resin (A) having an alicyclic group and no aromatic group (A), terpene phenol resin (B), and variant having a major axis / minor axis ratio of 1.5 to 10 A polyamide resin composition containing a modified cross-section glass fiber (C) having a cross section, wherein the composition exhibits the following characteristics:
(B) Apparent glass transition temperature of 125 to 160 ° C
(B) melt viscosity at a temperature 285 ° C. is, shear rates in 12.2Sec ^-1 at 1000 ~ 2000 Pa · s, and 100 to the shear rate of 1216 sec ^-1 350 Pa · s
(2) The amount of the amorphous polyamide resin (A) is based on the total mass of the amorphous polyamide resin (A), the terpene phenol resin (B), and the modified cross-section glass fiber (C). 30 to 69.5 mass%, the blending amount of the terpene phenol resin (B) is 0.5 to 10 mass%, and the blending amount of the modified cross-section glass fiber (C) is 30 to 60 mass% ( The polyamide resin composition for injection molding as described in 1).
(3) The polyamide resin for injection molding according to (1) or (2), wherein the amorphous polyamide resin (A) is a polyamide resin formed by polycondensation of an aliphatic dicarboxylic acid and an alicyclic diamine. Composition.
(4) The aliphatic dicarboxylic acid of the amorphous polyamide resin (A) is selected from dicarboxylic acids having 12 to 18 carbon atoms, and the alicyclic diamine is bis (4-amino-cyclohexyl) methane, bis (3-) is selected from (3-amino-cyclohexyl) methane, bis (3-methyl-4-amino-cyclohexyl) methane, and 2,2-bis (4-amino-cyclohexyl) propane. Polyamide resin composition for injection molding.
(5) When the irregular cross-section glass fiber (C) is blended, 0.1 to 3 parts by mass of a silane coupling agent is added to 100 parts by mass of the irregular cross-section glass fiber (C). The polyamide resin composition for injection molding as described in any one of) to (4).
(6) The ratio (LSv / HSv) of the melt viscosity (LSv) at a shear rate of 12.2 sec ^{−1 to} the melt viscosity (HSv) at a shear rate of 1216 sec ⁻¹ is 4.0 to 7.0 (1) The polyamide resin composition for injection molding according to any one of (5) to (5).
(7) A molded article for an electronic device molded from the polyamide resin composition for injection molding according to any one of (1) to (6).
(8) The molded product for an electronic device according to (7), wherein the electronic device is a portable electronic device.

The polyamide resin composition of the present invention is mainly composed of an amorphous polyamide resin of a specific component and a glass fiber having an irregular cross section, contains a terpene phenol resin, has an apparent glass transition temperature within a specific range, and is injected. Since the melt viscosity at the time of molding is controlled to be within a specific range at a low shear rate and a high shear rate, it is possible to achieve both thin formability and suppression of burr generation, and glass that does not require deburring A fiber-reinforced polyamide injection molded article can be provided.

FIG. 1 is a projection view of a model molded product that has been evaluated for occurrence of burrs. It is a mobile phone model shape, details are as follows. Molded product thickness: 1.3 mm, gate position: ● position in the figure, φ1.2 mm pin gate, degassing, 0.02 mm groove is installed around the entire circumference of the molded product, burr observation section (1): position in the figure , Near the gate, Bali observation section (2): position in the figure, near the final filling section

The present invention will be specifically described below.
The polyamide resin composition of the present invention has an alicyclic group, an amorphous polyamide resin (A) having no aromatic group, a terpene phenol resin (B), and a ratio of major axis / minor axis of 1. The glass fiber (C) having a modified cross section having a modified cross section of 5 to 10 is contained, and the apparent glass transition temperature of the polyamide resin composition is 125 to 160 ° C. The apparent glass transition temperature is preferably from 130 to 155 ° C, more preferably from 135 to 153 ° C. If the apparent glass transition temperature of the polyamide resin composition is less than 125 ° C., the glass transition temperature is further lowered by water absorption, so that the rigidity during heating is lowered and there is a possibility that problems such as deformation may occur, which is not preferable. If the temperature exceeds 160 ° C., the mold temperature necessary for obtaining a filling property and a good appearance is remarkably increased, so that the moldability is impaired.
The apparent glass transition temperature is a typical DSC measuring apparatus, heated to 300 ° C. at a rate of temperature increase of 20 ° C./min under a nitrogen stream, held at that temperature for 5 minutes, and then 10 ° C./min. It is the numerical value which measured the midpoint glass transition temperature (Tmg) as described in JISK7121 recognized when it temperature-falls to 50 degreeC with the speed | rate of (5).
In order for the polyamide resin composition of the present invention to have an apparent glass transition temperature of 125 to 160 ° C., the amorphous polyamide resin (A) in the present invention has a glass transition temperature of about 130 to 165 ° C. Is preferred. More preferably, it is 135 to 160 ° C, and still more preferably 135 to 155 ° C. If the glass transition temperature of the amorphous polyamide resin (A) is less than 130 ° C., the glass transition temperature is further lowered by water absorption, so that the rigidity during heating is lowered, and problems such as deformation may occur. When the glass transition temperature of the amorphous polyamide resin (A) exceeds 165 ° C., impact resistance and toughness become poor. Further, when the glass transition temperature is high, the filling property is difficult, so it is necessary to set the mold temperature and the resin temperature at the time of molding extremely high, which is not preferable in terms of energy saving. Moreover, when it has an aromatic group, toughness will become inferior.
The term “amorphous” as used in the present invention means that it does not show a clear melting point when DSC measurement is performed at a temperature rising rate of 20 ° C./min according to JIS K7121.

The polyamide resin composition of the present invention, the melt viscosity at a temperature 285 ° C. is at 1000 ~ 2000 Pa · s at a shear rate 12.2Sec ^-1, and it is necessary and shear rate 1216 sec ^-1 at 100 ~ 350 Pa · s It is. Since the melt viscosity at a temperature of 285 ° C. is 100 to 350 Pa · s at a shear rate of 1216 sec ⁻¹ , the melt fluidity in the middle stage of molding and filling, which is the peak stage of filling of the molten resin composition into the mold cavity, is achieved. By being ensured and having good thin-wall formability and a shear rate of 12.2 sec ⁻¹ of 1000 to 2000 Pa · s, the melt fluidity is lowered at the end of molding filling, and the effect of suppressing the occurrence of burrs is exhibited.
The behavior of the melt fluidity is such that the ratio of major axis / minor axis is 1. Amorphous polyamide resin (A) having no alicyclic group and no aromatic group, terpene phenol resin (B), and major axis / minor axis ratio. It can be expressed by combination with a modified cross-section glass fiber (C) having a modified cross section of 5 to 10.
The amount ratio of the amorphous polyamide resin (A), the terpene phenol resin (B), and the modified cross-section glass fiber (C) is preferably the amount ratio described below.

Further, the molding stability is such that the ratio (LSv / HSv) of the melt viscosity (LSv) at a shear rate of 12.2 sec ^{−1 to} the melt viscosity (HSv) at a shear rate of 1216 sec ⁻¹ is 4.0 to 7.0. From the viewpoint of sex. When LSv / HSv exceeds 7.0, there is a tendency that variation in molding tends to occur, and when LSv / HSv is less than 4.0, there is a tendency that the burr suppressing effect is hardly exhibited.

Furthermore, when the melt index (temperature: 275 ° C., load: 5 kg) measured in accordance with ISO 1133 is 10 g / 10 min or more, the polyamide resin composition of the present invention can easily achieve both the thin-wall formability and the burr generation suppressing effect. Therefore, it is preferable.

In the present invention, the amorphous polyamide resin (A) having an alicyclic group and not having an aromatic group is a monomer in which at least one monomer constituting the polyamide has an alicyclic group. It is an amorphous polyamide which does not contain an aromatic group as a monomer to be used. As described above, the term “amorphous” in the present invention does not indicate a clear melting point peak when DSC measurement is performed at a rate of temperature increase of 20 ° C./min according to JIS K7121.
The amorphous polyamide resin (A) in the present invention is preferably a polyamide resin formed by polycondensation of an aliphatic dicarboxylic acid and an alicyclic diamine.

Among the monomers constituting the amorphous polyamide resin (A), alicyclic diamines include bis (4-amino-cyclohexyl) methane (may be abbreviated as PACM), bis (3-amino-cyclohexyl) methane. Bis (3-methyl-4-amino-cyclohexyl) methane (may be abbreviated as MACM), 2,2-bis (4-amino-cyclohexyl) propane, isophoronediamine, 1,3-bis (aminomethyl) Cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 3-aminocyclohexyl-4-aminocyclohexylmethane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (aminopropyl) piperazine, bis (Aminoethyl) piperazine and the like can be mentioned.
Among the monomers constituting the amorphous polyamide resin (A), examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid (may be abbreviated as 12). And aliphatic dicarboxylic acids having a linear or branched chain having 4 to 36 carbon atoms, such as tridecanedioic acid and tetradecanedioic acid (sometimes abbreviated as 14).
As monomers constituting the amorphous polyamide resin (A), lactams such as ε-caprolactam and ω-laurolactam, aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, tetra Aliphatic diamines such as methylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4 / 2,4,4-trimethylhexamethylene diamine and 5-methylnonamethylene diamine may be included. good.

Examples of the monomer combinations include bis (4-amino-cyclohexyl) methane (PACM), bis (3-amino-cyclohexyl) methane, bis (3-methyl-4-amino-cyclohexyl) methane (MACM), 2,2 -Fatty acids selected from alicyclic diamines selected from bis (4-amino-cyclohexyl) propane and dicarboxylic acids having 12 to 18 carbon atoms such as undecanedioic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid A combination with a group dicarboxylic acid is preferred in terms of melt flow characteristics. As the aliphatic dicarboxylic acid, dodecanedioic acid and tetradecanedioic acid are more preferable, and tetradecanedioic acid is more preferable.
Further, a combination of MACM and dodecanedioic acid (MACM · 12), MACM and tetradecanedioic acid (MACM · 14) is preferable in terms of low water absorption and small change in water absorption dimension. Among them, MACM 14 can be molded at a molding temperature of 300 ° C. or less, and is excellent in strength, rigidity, impact resistance, and toughness even when the mold temperature is 100 ° C. It is preferable in that it can be easily obtained.

The molecular weight of the amorphous polyamide resin used in the present invention is not particularly limited, but the number average molecular weight measured by the method described below is preferably in the range of 3000 to 40000. The range of 7000 to 30000 is more preferable, and the range of 10,000 to 25000 is more preferable. If the number average molecular weight is less than 3000, the mechanical strength is lowered. Conversely, if the number average molecular weight is more than 40000, the molecular weight becomes too high and the moldability is deteriorated. The compounding amount of the amorphous polyamide resin in the present invention is 30 to 69.5 mass with respect to the total mass of the amorphous polyamide resin (A), the terpene phenol resin (B), and the modified cross-section glass fiber (C). % Is preferred. More preferably, it is 35 to 59% by mass, and still more preferably 40 to 54% by mass. This preferred range is derived from the ranges described below for the preferred ranges of the terpene phenol resin (B) and the modified cross-section glass fiber (C).

The terpene phenol resin used in the present invention is compatible with the amorphous polyamide resin used in the present invention, and can lower the apparent glass transition temperature of the amorphous polyamide resin-containing composition, and increase the melt fluidity. Therefore, compared to the case where terpene phenolic resin is not blended, it is difficult for the filling property to occur even if the molding temperature and mold temperature are lowered, so the cooling time can be shortened and the molding condition range can be widened. Can be taken. In particular, the combination with MACM · 14 is preferable because the apparent glass transition temperature decreases greatly.

Since the terpene phenol resin has many hydroxyl groups, it is incorporated into the amide group of the polyamide by hydrogen bonding, and as a result, the glass transition temperature of the polyamide can be apparently lowered. The same effect can be obtained by water absorption or a liquid plasticizer, but the effect is difficult or unstable due to volatilization by molding or extrusion. Further, in the case of a thin molded product, if the volatilization amount at the time of molding is large, the final filling portion of the product is burnt and it is difficult to remove a good product. Since the terpene phenol resin does not volatilize and remains in the polyamide resin, a stable effect can be exhibited.

The terpene phenolic resin used in the present invention is a reaction obtained by copolymerizing a monomer component composed of a terpene monomer and a phenolic monomer in an organic solvent in the presence of a Friedel-Craft type catalyst, or further hydrogenating after copolymerization. It means a part of the mixture or the whole composition.

The terpene monomer is a hydrocarbon compound represented by the molecular formula of (C ₅ H ₈ ) n or an oxygen-containing compound derived therefrom. For example, monoterpenes (when n = 2, myrcene, osymene, pinene, limonene) , Citronole, borneol, menthol, camphor, etc.), sesquiterpenes (when n = 3, curcumen, etc.), diterpenes (when n = 4, camphorene, hinokiol, etc.), tetraterpenes (when n = 8) , Carotenoids, etc.) and polyterpenes (natural rubber). Preferred terpenes are monoterpenes, particularly pinene and limonene.

The phenolic monomer is a compound having at least one hydroxyl group in an aromatic ring such as a benzene ring or a naphthalene ring, and may have a substituent (for example, a halogen atom, an alkyl group, etc.) in the aromatic ring. For example, phenol, cresol, xylenol, naphthol, catechol, resorcin, hydroquinone, pyrogallol and the like can be mentioned.

A preferred terpene phenol resin in terms of resistance to discoloration is a copolymer of monoterpenes and phenol. Copolymers of monoterpenes such as α-pinene and limonene and phenol are industrially easy to produce and more preferable.
The hydroxyl value (KOHmg / g) of the terpene phenol resin used in the present invention is usually preferably 150 or more, and more preferably 200 or more from the viewpoint of the effect of suppressing dimensional change due to water absorption.

The degree of polymerization of the terpene phenol resin used in the present invention is preferably about a number average molecular weight of about 500 to 10,000. If it is less than 500, the low molecular weight component may emit smoke upon heating and workability may be deteriorated. If it exceeds 10,000, it becomes a brittle material, which may affect the stickiness and compatibility. Specifically, there are, for example, YS polyster series and Mighty Ace series manufactured by Yashara Chemical Co., Ltd.

The blending amount of the terpene phenol resin in the present invention is 0.5 to 10 with respect to the total mass of the amorphous polyamide resin (A), the terpene phenol resin (B), and the modified cross-section glass fiber (C). The content is preferably mass%, more preferably 1 to 5 mass%. If the amount is less than 0.5% by mass, almost no expression of the blending effect is observed, and if it exceeds 10% by mass, the mechanical strength is lowered or the terpene phenol deposited on the surface is peeled off.

The glass fiber used in the present invention is a glass fiber having a modified cross-sectional shape having a major axis / minor axis ratio of 1.5 to 10, preferably having a major axis / minor axis ratio of 2.0 to 6.0. It is. When the major axis / minor axis ratio is less than 1.5, the effect of reducing warpage is poor, and when the major axis / minor axis ratio exceeds 10, it is difficult to produce glass fibers themselves. The irregular cross-sectional shape may be any shape such as an elliptical shape, a gourd shape, an eyebrows shape, an oval shape, a rectangular shape, etc., the short diameter is the shortest diameter distance of the cross section, and the long diameter is the longest diameter distance of the cross section. Point to. The major axis is preferably 10 to 50 μm and the minor axis is preferably in the range of 5 to 20 μm.

Further, it is preferable to use short fiber type chopped strands for the glass fiber. The chopped strand is preferably a glass fiber having a length of 3 to 6 mm, and more preferably 4 to 5 mm.

The blending amount of the irregular cross-section glass fiber in the present invention is 30 to 60 mass with respect to the total mass of the amorphous polyamide resin (A), the terpene phenol resin (B), and the irregular cross-section glass fiber (C). % Is preferred. More preferably, it is 40 to 60% by mass, and still more preferably 45 to 55% by mass. If it is less than 30% by mass, the mechanical strength of the molded product is low, and if it exceeds 60% by mass, the resin has poor fluidity, and if it is thin, it is difficult to obtain a molded product with high dimensional accuracy.

The modified cross-section glass fiber is preferably treated with a coupling agent such as a silane-based or titanate-based fiber, and particularly preferably treated with a silane-based coupling agent.
Preferred silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-anilinopropyl. Examples include trimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like. Glycidoxypropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane are preferred.
The silane coupling agent is preferably newly added immediately before compounding with the polyamide resin, in addition to those previously given at the time of glass fiber production. The amount of coupling agent applied is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the glass fiber. If it is less than 0.1 parts by mass, the effect of imparting is small, and if it exceeds 3 parts by mass, it is not economical, and gas generation during molding increases, and the appearance deteriorates. However, in the case of using a glass fiber having an improved silane coupling agent that is preliminarily applied at the time of glass fiber production, no new application is particularly required.

In addition to the above, the polyamide resin composition of the present invention includes a light or heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a plasticizer, a lubricant, a crystal nucleus within a known range as necessary. Additives, mold release agents, antistatic agents, combinations of halogenated flame retardants and antimony trioxide, various phosphate flame retardants, melamine flame retardants, inorganic pigments, organic pigments, dyes, or other types of polymers I can do it.

As a production method for producing the polyamide resin composition of the present invention, at least the components (A), (B) and (C) described above and other blends are blended in any blending sequence in the blending composition. After that, the mixture is mixed with a tumbler or a Henschel mixer and melted and kneaded. The melt kneading method can be any method known to those skilled in the art, and a single screw extruder, a twin screw extruder, a kneader, a Banbury mixer, a roll, etc. can be used, among which a twin screw extruder is used. It is preferable to do.
In addition, it is preferable that glass fiber having a modified cross-sectional shape of the component (C) that is easily damaged during extrusion processing is introduced from the side port of the twin-screw extruder to prevent the glass fiber from being damaged, but is particularly limited. It is not something. Moreover, although a silane coupling agent may be added simultaneously with raw material components other than (C), it is preferable to add to the (C) component in advance.
In addition, in order to remove volatile components and decomposed low-molecular components during processing, and to increase the reactivity of the modified resin and reinforcing material with the polyamide resin, the side opening of the glass fiber input portion and the tip of the extruder It is desirable to perform suction with a vacuum pump between the die head.

EXAMPLES Next, although this invention is demonstrated concretely using an Example and a comparative example, this invention is not limited to these.
(1) Raw materials used in Examples and Comparative Examples Raw materials used in Examples and Comparative Examples are as follows.

(A) Polyamide resin MACM 14: Arkema G350, glass transition temperature 145 ° C., number average molecular weight 14200, amorphous MACM 12: EMS TR-90, glass transition temperature 155 ° C., number average molecular weight 13300, Amorphous MACM 12 · I: TR-55 manufactured by EMS, glass transition temperature 162 ° C., number average molecular weight 18600, amorphous polyamide 66: manufactured by Toray Industries, Inc., E3000F, glass transition temperature 49 ° C., weight average molecular weight 13000, Crystalline 6T6I (6T / 6I = 33/67 (mol%)): EMS Grivory G21, glass transition temperature 125 ° C., number average molecular weight 15100, amorphous MACM is bis (3-methyl-4-amino-cyclohexyl) ) Methane, 12 is dodecanedioic acid, 14 is tetradecanedioic acid, I is isophthalic acid, T is terephthalic acid To express.
The number average molecular weight was determined as follows.
2 mg of each sample was weighed and dissolved in 4 ml of HFIP / sodium trifluoroacetate 10 mM. It filtered with the 0.2 micrometer membrane filter, and the gel permeation chromatography (GPC) analysis of the obtained sample solution was performed on the following conditions.
Equipment: TOSOH HLC-8220GPC
Column: TSKgel SuperHM-H × 2, TSKgel SuperH2000
Flow rate: 0.25 ml / min, concentration: 0.05%, temperature: 40 ° C., detector: RI
The molecular weight conversion was calculated in terms of standard polymethyl methacrylate.
The molecular weight was calculated by excluding those having a molecular weight of 1000 or less as oligomers.

(B) Terpene phenol-based resin YShara Chemical Co., Ltd. YS Polystar S145
(C-1) Modified cross section glass fiber 3PA820S manufactured by Nittobo Co., Ltd. (ratio of major axis / minor axis 4)
(C-2) Modified cross-section glass fiber 2
Nittobo Co., Ltd. 3PA810S (major axis / minor axis ratio 4)
(D) Other additives ・ Stabilizer: Hindered phenol Ciba Specialty Chemicals, IRGANOX245; (A), (B), (C-1) or (C-2) to 100 parts by mass in total 0.5 parts by mass were used.
-Mold release agent: Montanic acid ester Clariant Japan Co., Ltd., WE40; 0.6 mass part was used with respect to a total of 100 mass parts of (A), (B), (C).
Coupling agent: Aminopropyltriethoxysilane, manufactured by Momentive Performance Materials Japan G.K., A-1100; 0.3 parts by mass with respect to 100 parts by mass of the modified cross-section glass fiber (C) was used.

(2) Characteristics and physical property values The following test methods were adopted for the respective properties and physical property values of the resins and resin compositions shown in the Examples and Comparative Examples below.
(B) Glass transition temperature:
A DSC measuring device (EXSTAR6000, manufactured by Seiko Instruments Inc.) was used. According to JIS K7121 recognized when the temperature was raised to 300 ° C at a rate of temperature increase of 20 ° C / min under a nitrogen stream, held at that temperature for 5 minutes, and then decreased to 50 ° C at a rate of 10 ° C / min. The described midpoint glass transition temperature (Tmg) was measured.
The glass transition temperature was measured from the results of the second cycle by measuring two cycles under the same conditions using the same sample in order to eliminate the effects of water absorption and thermal history.

(B) Melt shear viscosity:
A capillary rheometer (Toyo Seiki Co., Ltd., product name Capillograph 1B) was used.
Capillary shape: hole diameter 1.0mm, length 30mm
Shear rate: 12.2 sec ⁻¹ (1.0 mm / min)
Shear rate: 1216 sec ⁻¹ (100.0 mm / min)
Measurement temperature: 285 ° C

(C) Melt index:
It measured according to ISO1133.
Measurement temperature: 275 ° C
Load: 5kg

(D) Tensile strength, tensile elongation: measured in accordance with ISO-527-1.2.
(E) Bending strength, bending elastic modulus, bending deflection rate: Measured according to ISO-178.
(F) Charpy impact strength: Measured according to ISO-179-1eA.

(G) Paint adhesion:
Urethane paint was applied with a spray gun to a paint film thickness of about 30 μm. The baking temperature is 100 ° C. × 30 minutes, and the adhesion strength is φ10 mm, length 300 mm, a cylindrical jig with a hook on one side is bonded to the molded product using Aron Alpha 101, and the hook part is bonded. The peel strength of the coating film was determined by pulling with a push-pull gauge.
A: The peel strength exceeds 25 kg, and the broken base material is attached to the peeled paint.
○: Peeling force is 15 kg or more and 25 kg or less.
X: Peeling force is less than 15 kg.

(H) Dimensional stability:
A plate of 100 × 100 × 2 mm (film gate) was molded (cylinder temperature 295 ° C., mold temperature 110 ° C.) with the compositions of Examples and Comparative Examples, and evaluated by the dimensional increase rate at the time of 95% RH equilibrium water absorption. . The water absorption treatment was an accelerated water absorption treatment at 80 ° C. in a constant temperature bath of 95% relative humidity.
A: Less than 0.05%, B: 0.05 to less than 0.1%, X: 0.1% or more

(3) Molding characteristics Easy moldability and evaluation of burrs An injection molding machine (manufactured by Toshiba Machine Co., Ltd., EC-100N, electric molding machine, mold clamping force 100 ton, screw diameter is 32 mm) and has the shape shown in FIG. Table 1 shows the required cylinder temperature, mold temperature, and injection pressure for ease of molding using a telephone model mold (φ1.2 mm pin gate, thickness 1.3 mm, width 45 mm, length 100 mm). It was evaluated with the evaluation score.

-Easily moldable The easy moldability was determined from the total of the above scores as follows.
6 or more: ◎ (good),
5-3: ○ (almost good)
2 to 1: △ (somewhat bad)
1 to 0: × (defect)
・ Bali evaluation:
Two portions near the gate and the final filling portion where burrs are likely to occur in the molded product using the mobile phone model mold shown in FIG. 1 were measured with a microscope KH-7700 manufactured by HIROX.
200 shots were molded, and the variation of burrs generated in the observation part (1) and the observation part (2) was evaluated. Table 3 shows the burrs generated in the observation part (1) as “minimum value (μm) to maximum value (μm)” and the burrs generated in the observation part (2) as “average value (μm)”.
Regarding the stability evaluation of burr generation related to productivity, 200 shots are molded, and the maximum value and variation (difference between the maximum value and minimum value) of the burr generated in 200 shots of the observation part (1) are as follows. It was evaluated as follows.
A: Maximum burr value is 50 μm or less and variation is 25 μm or less B: Maximum burr value is 60 μm or less and variation is 30 μm or less Δ: Maximum burr value is 100 μm or less and variation 50 μm or less x: The maximum value of burr exceeds 100 μm

Examples 1-7, Comparative Examples 1-4
After blending each component except glass fiber with a tumbler so as to have the composition shown in Table 2 below (including the stabilizer and mold release agent), it is melt-kneaded with a twin-screw extruder (STE35 manufactured by Coperion). Thus, composition pellets were obtained. The aminosilane coupling agent was added by coating a predetermined amount on the glass fiber immediately before the glass fiber was added by side feed.
The obtained composition pellets were dried and then evaluated by the method described above. The results are shown in Tables 2 and 3.

In the resin compositions of Examples 1 to 7, the apparent glass transition temperature and the melt viscosity satisfy the scope of the present invention, so that the moldability is excellent and the burr generation suppressing effect is excellent. It can be seen that the paint adhesion is also excellent. In particular, in Examples 1 and 3, it can be seen that the tensile elongation and the bending deflection ratio are large and the toughness is excellent. Furthermore, since molding can be performed without problems even at a low filling pressure, the stability during continuous molding is also excellent. In addition, the dimensional change after water absorption is very small and the dimensional stability of the product is excellent.
In Comparative Example 1 in which no terpene phenol-based resin is blended, there is room for improvement in moldability, burr suppression effect, paint adhesion, and the like. In particular, due to poor moldability, filling is not performed unless a very high filling pressure is applied, so that the amount of burrs generated varies even when the resin stays during continuous molding or the mold temperature slightly changes. . Since Comparative Example 2 using an amorphous polyamide resin having an alicyclic group but having an aromatic group has a high glass transition temperature, the filling property is lowered and the effect of suppressing the generation of burrs is inferior and the toughness of the molded product is low. Inferior. There is also a variation in the occurrence of burrs.
The amorphous polyamide resin of Comparative Example 3 had good moldability even when terpene phenol was not added since the original glass transition temperature was low, but the result was poor dimensional stability upon water absorption. . Moreover, since the aromatic ratio was high, it became a very brittle molded product. The crystalline polyamide of Comparative Example 4 was inferior in dimensional stability and difficult to suppress burrs.

Industrial applicability

The polyamide resin composition of the present invention is excellent in production stability, has little fluctuation in mechanical strength, thin-wall moldability, dimensional stability, etc., and can reduce the occurrence of burrs in thin-walled injection molded products as much as possible, and further in coating adhesion For example, portable electrical appliances that place importance on weight reduction and design as well as mechanical properties, such as mobile phones, portable music listening products, portable video viewing products, and portable personal computer casings. It is suitable for materials.

1: Gate position 2: Burr observation part (1); Near gate 3: Burr observation part (2); Near final filling part

Claims

Amorphous polyamide resin (A) having no alicyclic group and no aromatic group (A), terpene phenol resin (B), and an irregular cross section having a major axis / minor axis ratio of 1.5 to 10 A polyamide resin composition containing a modified cross-section glass fiber (C), wherein the composition exhibits the following characteristics:
(B) Apparent glass transition temperature of 125 to 160 ° C
(B) melt viscosity at a temperature 285 ° C. is, shear rates in 12.2Sec -1 at 1000 ~ 2000 Pa · s, and 100 to the shear rate of 1216 sec -1 350 Pa · s
The blending amount of the amorphous polyamide resin (A) is 30 to 69 with respect to the total mass of the amorphous polyamide resin (A), the terpene phenol resin (B), and the modified cross-section glass fiber (C). The blending amount of the terpene phenolic resin (B) is 0.5 to 10% by weight, and the blending amount of the modified cross-section glass fiber (C) is 30 to 60% by weight. The polyamide resin composition for injection molding as described.
3. The polyamide resin composition for injection molding according to claim 1, wherein the amorphous polyamide resin (A) is a polyamide resin formed by polycondensation of an aliphatic dicarboxylic acid and an alicyclic diamine.
The aliphatic dicarboxylic acid of the amorphous polyamide resin (A) is selected from dicarboxylic acids having 12 to 18 carbon atoms, and the alicyclic diamine is bis (4-amino-cyclohexyl) methane, bis (3- 4. For injection molding according to claim 3, wherein the compound is selected from amino-cyclohexyl) methane, bis (3-methyl-4-amino-cyclohexyl) methane, and 2,2-bis (4-amino-cyclohexyl) propane. Polyamide resin composition.
The silane coupling agent of 0.1 to 3 parts by mass is added to 100 parts by mass of the irregularly shaped glass fiber (C) when the irregularly shaped glass fiber (C) is blended. The polyamide resin composition for injection molding according to any one of the above.
The ratio (LSv / HSv) of the melt viscosity (LSv) at a shear rate of 12.2 sec -1 to the melt viscosity (HSv) at a shear rate of 1216 sec -1 is 4.0 to 7.0. The polyamide resin composition for injection molding according to any one of the above.
A molded article for electronic equipment molded from the polyamide resin composition for injection molding according to any one of claims 1 to 6.
The molded product for an electronic device according to claim 7, wherein the electronic device is a portable electronic device.