JPH107894A - Box-shaped moldings made of polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain box-shaped polyester resin moldings which are excellent in dimensional stability and resistance to shock and is improved in peeling in occurring around a gate by molding a material containing a polyester resin, a polycarbonate resin and a specific graft copolymer. SOLUTION: This resin material for molding comprises (A) 20-90wt.% of a resin material containing (i) 60-95wt.% of a thermoplastic polyester resin and (ii) 5-40wt.% of a polycarbonate resin, (B) 5-30wt.% of a graft polymer prepared by chemically bonding 40-10wt.% of (iv) a (co)polymer of an alkyl unsaturated carboxylate ester onto 60-90wt.% of (iii) an ethylene/an unsaturated carboxylic alkyl ester copolymer or an ethylene/unsaturated carboxylic alkyl ester/unsaturated carboxylic glycidyl ester copolymer by the branching or crosslinking manner and (C) 5-50wt.% of a fibrous filler, a non-fibrous inorganic filler or their mixture. The objective moldings are preferably formed by using a sub-marine gate or a pin gate with a diameter of <=1.2mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a molded article comprising a thermoplastic polyester resin composition. More specifically, the present invention relates to a box-shaped molded product having excellent dimensional stability and impact resistance and having improved peeling around a gate portion.

[0002]

2. Description of the Related Art A composition obtained by blending a thermoplastic polyester resin represented by polyethylene terephthalate or polybutylene terephthalate with an inorganic filler such as glass fiber can be injection-molded. Because of their excellent mechanical properties, they are widely used in the fields of electric / electronic parts and automobile parts. However, a resin composition containing a fibrous reinforcing agent such as glass fiber has high mechanical strength and rigidity, but when producing a box-shaped molded article or the like due to anisotropy occurring at the time of molding, the resin composition is not suitable. Warpage deformation occurs in the molded product, and its application is particularly limited in the field of precision molded products and the like in which strict dimensional accuracy is required. On the other hand, with the expansion and diversification of applications, higher performance is often required. One of such properties is improvement in impact resistance, and the demand for lighter products, which has been seen in recent years, has been reduced in thickness of molded products, and the demand has been increasing. In order to meet such a demand, a method of blending a thermoplastic polyester resin with a linear olefin polymer, for example, a thermoplastic elastomer such as ethyl acrylate has been proposed. In recent years, due to automation of molding work or high efficiency due to reduction of molding cycle, a submarine gate or a pin gate having a smaller gate diameter has been increasingly used instead of the conventional side gate. Although the impact resistance of the polyester resin blended with such an elastomer is improved, in a molded article having a submarine gate or a pin gate, molding is performed due to a high shear rate at the gate portion during molding and poor compatibility between the resins. There has been a problem that peeling occurs around the gate portion of the product and the appearance of the molded product is impaired.

[0003]

In view of such demands, the present inventors have made use of a thermoplastic polyester resin composition to provide excellent dimensional stability, and to generate a peripheral portion of a gate without impairing excellent impact resistance. As a result of intensive studies to obtain a box-shaped molded product with improved peeling, the present invention has been achieved. That is, the present invention relates to (A) a resin material composed of 60 to 95% by weight of a thermoplastic polyester resin (A-1) and 5 to 40% by weight of a polycarbonate resin (A-2); For an unsaturated carboxylic acid alkyl ester copolymer or an ethylene / unsaturated carboxylic acid alkyl ester / unsaturated carboxylic acid glycidyl ester copolymer (B-1) 60 to 90% by weight,
One to two or more unsaturated carboxylic acid alkyl ester (co) polymers (B-2), 40 to 10% by weight, 5 to 30% by weight of a graft copolymer in which a branched or cross-linked structure is chemically bonded,
(C) A polyester resin box-shaped molded product obtained using a resin material comprising 5 to 50% by weight of a fibrous filler, a non-fibrous inorganic filler or a mixture of both.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The components of the resin composition used for the box-shaped molded article of the present invention will be described in detail below. First, the thermoplastic polyester resin (A-1), which is a base resin of the resin composition used in the present invention, is a polycondensation of a dicarboxylic acid compound and a dihydroxy compound, a polycondensation of an oxycarboxylic acid compound, or a polycondensation of a mixture of these three components. It is a polyester obtained by condensation or the like, and the effects of the present invention are exerted on both homopolyesters and copolyesters. Illustrative examples of the dicarboxylic acid compound constituting the thermoplastic polyester resin used here include terephthalic acid,
Known dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid and sebacic acid, and alkyl, alkoxy or halogen-substituted products thereof. These dicarboxylic acid compounds can also be used for polymerization in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. Two or more of these may be used.
Next, examples of the dihydroxy compound constituting the polyester (A-1) of the present invention include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcin, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, and cyclohexanediol. , 2,2-bis (4-hydroxyphenyl) propane, dihydroxy compounds such as diethoxylated bisphenol A, polyoxyalkylene glycols and their alkyl, alkoxy or halogen-substituted products, etc., and they are used alone or in combination of two or more. be able to. Also, if you show an example of oxycarboxylic acid,
Oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and alkyl, alkoxy or halogen-substituted products thereof. Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or more of these compounds are used. In addition, a polyester having a branched or crosslinked structure using a small amount of a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like may be used. In the present invention, any of the thermoplastic polyesters produced by polycondensation can be used as the component (A-1) of the present invention, using the above-described compound as a monomer component, alone or as a mixture of two or more. Preferably, polyalkylene terephthalate, more preferably polybutylene terephthalate or a mixture based on this is used.

In the present invention, the polybutylene terephthalate resin (A-1) is replaced with the polycarbonate resin (A-2).
Is blended. This polycarbonate resin, solvent method,
That is, a known acid acceptor in a solvent such as methylene chloride, in the presence of a molecular weight modifier, the reaction of a dihydric phenol and a carbonate precursor such as phosgene or a dihydric phenol and a carbonate precursor such as diphenyl carbonate. Can be produced by a transesterification reaction. Here, bisphenols are preferably used as the dihydric phenol, and 2,2-bis (4-hydroxyphenyl) propane, that is, bisphenol A is particularly preferable. Further, bisphenol A may be obtained by partially or entirely substituting another dihydric phenol. Examples of dihydric phenols other than bisphenol A include hydroquinone, 4,4-dihydroxydiphenyl, bis (4-hydroxyphenyl) alkane, bis (4-hydroxyphenyl) cycloalkane, and bis (4-hydroxyphenyl)
Compounds such as sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ether or bis (3,5-dibromo-4-hydroxyphenyl) propane, bis ( Halogenated bisphenols such as 3,5-dichloro-4-hydroxyphenyl) propane can be mentioned. These dihydric phenols may be a homopolymer or a copolymer of two or more dihydric phenols. Further, the polycarbonate resin used in the present invention may be a thermoplastic random branched polycarbonate obtained by reacting a polyfunctional aromatic compound with a dihydric phenol and / or a carbonate precursor.

The proportion of the thermoplastic polyester resin (A-1) to the polycarbonate resin (A-2) is 60 to 95% by weight of the component (A-1) and 5 to 5% by weight of the component (A-2). 40% by weight. (A-2) If the added amount of the component is less than 5% by weight, the shape stability or surface appearance such as occurrence of sink marks on the thick part of the molded product is poor. Undesirably, molding problems such as an increase in cycles and deterioration of releasability occur. The resin material composed of (A-1) and (A-2) is used in an amount of 20 to 90% by weight.

The graft copolymer used as the component (B) in the present invention is an ethylene / unsaturated carboxylic acid alkyl ester copolymer or an ethylene / unsaturated carboxylic acid alkyl ester / unsaturated carboxylic acid glycidyl ester copolymer. One to two or more unsaturated carboxylic acid alkyl ester (co) polymers (B-2) 40 to 10% by weight, based on the polymer (B-1) 60 to 90% by weight, has a branched or crosslinked structure. It is a chemically bonded graft copolymer. The above copolymer (B-1)
Specific examples of ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / A random copolymer such as an ethyl acrylate / glycidyl methacrylate copolymer may be used. These copolymers can be used even if they are mixed. On the other hand, the unsaturated carboxylic acid alkyl ester (co) polymer (B-2) to be graft-copolymerized with the copolymer (B-1) is, for example, polymethyl methacrylate, polyethyl acrylate, or polybutyl acrylate. 2-ethylhexyl polyacrylate, polystyrene, polyacrylonitrile, acrylonitrile / styrene copolymer, butyl acrylate / methyl methacrylate copolymer, butyl acrylate / styrene copolymer, and the like. The component (B) which is a feature of the present invention includes an ethylene / unsaturated carboxylic acid alkyl ester copolymer, an ethylene / unsaturated carboxylic acid alkyl ester / unsaturated carboxylic acid glycidyl ester copolymer (B-1) or The unsaturated carboxylic acid alkyl ester (co) polymer (B-2) is not used alone, but the copolymer (B-1) and the (co) polymer (B-2) are chemically bonded at at least one point. It has the characteristic that it is a graft copolymer having a branched or crosslinked structure, and by having such a graft structure as described later, it is possible to simply blend (B-1) or (B-2) alone. A remarkable effect that cannot be obtained is obtained. Here, the ratio of (B-1) to (B-2) for constituting the graft copolymer of the component (B) needs to be 60/40 to 90/10 (weight ratio).
Further, the method for producing the graft copolymer of the component (B) used in the present invention may be any method such as a generally well-known chain transfer method and ionizing radiation irradiation method, and most preferably, the main chain (B -1) Grafting of polymers by melt-kneading a grafting precursor obtained by copolymerizing a monomer of component (B-2) and a radical (co) polymerizable organic peroxide in component particles. It is obtained by a chemical reaction. The reason for this is that the grafting efficiency is high and secondary aggregation due to heat does not occur, so that the expression of performance is more effective. (B)
The addition amount of the component is 5 to 30% by weight based on the whole resin composition.
If the amount of the component (B) is less than 5% by weight, the effect of improving the low-temperature impact resistance, which is the object of the present invention, cannot be obtained. Is not preferred because it inhibits

Next, as the filler of the component (C) used in the present invention, a fibrous or non-fibrous (pulverized, plate-like) filler is used. Examples of the fibrous filler include glass fiber, carbon fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium,
Inorganic fibrous substances such as fibrous materials of metals such as copper and brass can be used. Particularly typical fibrous fillers are glass fibers,
Or it is carbon fiber. Note that a high-melting-point organic fibrous substance such as polyamide, fluororesin, or acrylic resin can also be used. On the other hand, as a granular filler, carbon black, silica, quartz powder, glass beads, glass powder, milled glass fiber, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, and wollastonite Metal oxides such as salts, iron oxide, titanium oxide, zinc oxide, alumina, calcium carbonate, metal carbonates such as magnesium carbonate, calcium sulfate,
Sulfates of metals such as barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders. Examples of the plate-like filler include mica, glass flake, various metal foils, and the like. Among these, glass flake, mica powder, talc, glass beads, and milled glass fiber are particularly preferable as the non-fibrous inorganic filler. These inorganic fillers can be used alone or in combination of two or more.
The combined use of a fibrous filler, particularly a glass fiber and a granular and / or plate-like filler, is a preferable combination, particularly in terms of having both mechanical strength, dimensional accuracy, electrical properties and the like. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. This example is a functional compound such as an epoxy compound, an isocyanate compound, a silane compound and a titanate compound. These compounds may be used after being subjected to a surface treatment or a convergence treatment in advance, or may be added simultaneously with the preparation of the material.
The amount of the filler used as the component (C) is 5 to 5 in the total resin composition.
50% by weight. If the amount is too small, the effect of improving the high / low temperature impact resistance is small. If the amount is too large, the molding operation becomes difficult. The amount of the functional surface treating agent used in combination is 0 to 10% by weight, preferably 0.05 to 5% by weight, based on the filler.

In the resin composition used in the present invention, it is possible to use a small amount of another thermoplastic resin in a supplementary manner as long as its purpose is not impaired. Any other thermoplastic resin may be used as long as it is stable at high temperatures. For example, polyamide, A
BS, polyphenylene oxide, polyalkyl acrylate, polyacetal, polysulfone, polyethersulfone, polyetherimide, polyetherketone,
Fluororesins can be mentioned. These thermoplastic resins can be used as a mixture of two or more kinds.

[0010] The resin composition used in the present invention may further comprise a known substance generally added to a thermoplastic resin or the like, that is, an antioxidant, a heat stabilizer, Stabilizers such as ultraviolet absorbers, antistatic agents,
It is possible to blend a lubricant, a release agent, a coloring agent such as a dye or a pigment, a lubricant, a plasticizer, a crystallization accelerator, a crystal nucleating agent, and the like.

In particular, the addition of a stabilizer is effective for preventing corrosion and contamination of metals in contact with electronic parts and the like using molded products at high temperatures. As the stabilizer, hindered phenol compounds, amine compounds, phosphorus compounds, thioether compounds and the like can be used. One example of a hindered phenol compound is 1,6-hexanediol bis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,
5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-
t-butyl-5-methyl-4-hydroxyphenyl) propionate]. Examples of the amine compound include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, 4,4′-bis- (4-α, α-dimethylbenzyl) ) Diphenylamine, condensation products of diphenylamine and acetone, N-phenylnaphthylamine, N, N'-di-β-naphthylphenylenediamine and the like. As the phosphorus compound, a phosphite or phosphite-based organic compound is preferable. For example, triallyl phosphite such as triphenyl phosphite and tri (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, cyclic Neopentanetetrayl-bis- (2,4-di-t-butylphenyl-phosphite), di- (2,6-di-t-butyl-4)
Heat-resistant phosphites such as -methylphenyl) pentaerythritol diphosphite, tetrakis (2,4-
Phosphonite compounds such as (di-t-butylphenyl) -4,4-biphenylenephosphonite are typical examples.

The thioether compounds include dilaurylthiodipropionate, dimyristylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, tetrakis [methylene-3- (dodecylthio) propionate] methane. ,
Dialkyl (C ₁₂ ~C ₁₈₎ -3,3 - such as thiodipropionate and the like. The amount of the stabilizer is 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the total amount of the resin material.
It is.

[0013] The resin composition and the injection molded article of the present invention are:
It can be easily obtained by known equipment and methods generally used as conventional resin composition preparation methods and molding methods. For example, 1) a method of mixing each component, kneading and extruding with an extruder to prepare pellets, and then performing injection molding, 2) once preparing pellets having different compositions, mixing the pellets in a predetermined amount and injecting. Any method can be used, such as a method of providing a molded product having a desired composition after molding and 3) a method of directly charging one or more of each component to a molding machine. or,
Mixing and adding a part of the resin component as a fine powder with the other components is a preferable method for uniformly blending these components. In particular, in the case of molding work, in recent years, submarine gates or pin gates are often used in order to increase efficiency by automating the work or reducing the molding cycle. However, by using the resin composition of the present invention, the diameter (gate) is increased. Even if a mold having the gate having a diameter of 1.5 mm or less is used, a molded product in which peeling around the gate is suppressed can be obtained. In particular, the resin composition of the present invention can be preferably used for the gate having a gate diameter of 1.2 mm or less, and more preferably 1.0 mm or less.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 3 As shown in Table 1, polybutylene terephthalate (PBT) and polycarbonate were mixed as components (A), various graft copolymers as component (B), and glass fibers as component (C) were mixed at a predetermined ratio. The mixture was melt-kneaded with an extruder to prepare a pellet-shaped composition. Next, test pieces were prepared by injection molding using various gates, and physical properties were measured. Table 1 shows the results. The items evaluated and the measurement method are as follows.・ Izod impact strength (notched): Measured according to ASTM D-256 ・ Inward deformation test: Box-shaped molded product shown in Fig. 1 (Product dimensions: length = 40mm, width = 80mm, height = 40mm, meat) Thickness = 2mm)
1-1 'was measured. -Peeling test: Submarine gate (molded product: vertical = 15m)
m, width = 40mm, height = 35mm, wall thickness = 1mm, gate diameter = 1.
Peeling around a box-shaped product with a thickness of 0 to 1.5 mm) or a pin gate (a molded product with a length of 50 mm, a width of 50 mm, a thickness of 3 mm, and a gate diameter of 1.0 to 1.5 mm) The condition was evaluated according to the following criteria. ：: no peeling Δ: reduced peeling area ×: large peeling area Comparative Examples 1 to 5 For comparison, when the graft copolymer as component (B) was not blended (Comparative Example 1), the graft copolymer of the present invention was used. Instead of ethylene / ethyl acrylate (E / EA) copolymer and polymethyl methacrylate (PMMA) (Comparative Examples 2-3), without glass fiber (Comparative Example 4), and polycarbonate In the case where is not blended (Comparative Example 5), a pellet composition was prepared in the same manner as in the above example, and the physical properties were evaluated. Table 1 shows the results.

The component (B) and its constituent component (B
The substances used as -1) and (B-2) are as follows.
Are indicated by abbreviations. (B-1) E / EA: ethylene / ethyl acrylate (80/2
0) Copolymer E / EA / GMA: ethylene / ethyl acrylate / glycidyl methacrylate (75/20/5) copolymer (B-2) PMMA: polymethyl methacrylate BA / MMA: butyl acrylate / methacrylic Ethyl acid (70/30) copolymer (B) E / EA-g-PMMA: E / EA and PMMA
(70/30) graft copolymer E / EA-g-BA / MMA: E / EA and BA / MMA
E / EA / GMA-g-PMMA: Graft copolymer of E / EA / GMA and PMMA (70/30)

[0016]

[Table 1]

[0017]

As apparent from the above description and Examples, the molded article of the polyester resin composition of the present invention comprises a mixture of a polyester resin and a polycarbonate resin, and simultaneously improves the compatibility with the olefin elastomer. This is a molded product with excellent dimensional stability and improved surface delamination without impairing the conventional excellent impact resistance, and is expected to be used for various functional parts such as electric / electronic parts or automobile parts It is.

[Brief description of the drawings]

FIG. 1 is a view showing a box-shaped molded product used in a warp deformation test in an example and measurement points of dimensions thereof.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08L 69/00 LPR C08L 69/00 LPR // B29K 67:00 69:00

Claims (2)

[Claims] (1) a thermoplastic polyester resin (A-1)
20 to 90% by weight of a resin material comprising 95% by weight and 5 to 40% by weight of a polycarbonate resin (A-2); (B) an ethylene / unsaturated carboxylic acid alkyl ester copolymer or ethylene / unsaturated carboxylic acid alkyl ester / Unsaturated carboxylic acid glycidyl ester copolymer
(B-1) One or more unsaturated carboxylic acid alkyl ester (co) polymers (B-2)
10% by weight of a resin comprising 5 to 30% by weight of a graft copolymer which is chemically bonded in a branched or crosslinked structure; (C) 5 to 50% by weight of a fibrous filler, a non-fibrous inorganic filler or a mixture of both. A box-shaped molded product made of polyester resin obtained using the material. 2. The box-shaped molded product according to claim 1, wherein the molded product is formed by a submarine gate or a pin gate having a diameter of 1.2 mm or less.