JPH0790149A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in chemical resistance, transparency, compatibility between resins, and moldability and reduced in molding shrinkage by mixing a specific copolymer with an aromatic polyester resin. CONSTITUTION:100-80wt.% mixture of vinyl cyanide and an aromatic vinyl is copolymerized with 0-20wt.% other copolymerizable vinyl monomer(s) to obtain a copolymer (A) having an intrinsic viscosity of 0.3-1.3 and a ratio of weight-average mol.wt. to number-average mol.wt., Mw/Mn of 3.8 or lower. 40-95 pts.wt. the ingredient (A) is mixed with 60-5 pts.wt. aromatic polyester resin (B) having as essential components a dicarboxylic acid component consisting mainly of an aromatic dicarboxylic acid and a glycol component comprising cyclohexanedimethanol, in such a proportion that (3.85x-1.0)<=y<=(3.85x-0.2) [wherein x is the content by weight of the vinyl cyanide copolymer units contained in the ingredient (A) and y is the content by weight of the segments contained in the ingredient (B) which are made up of a cyclohexanedimethanol residue and a dicarboxylic acid residue].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has excellent chemical resistance, transparency, and compatibility between resins, so that there is no delamination of molded products, molding processability is excellent, and molding heat shrinkage is small. It relates to a plastic resin composition.

[0002]

2. Description of the Related Art Acrylonitrile-styrene copolymer resin (AS resin) has excellent moldability and transparency,
Widely used as a general-purpose thermoplastic resin. But,
There is a drawback that the chemical resistance is insufficient, and there are problems such as cracking of molded products by various chemical solutions and surface roughness due to suction of paint, and the present situation is that use is limited depending on the application.

On the other hand, an aromatic polyester resin (hereinafter abbreviated as polyester) generally has excellent chemical resistance, mechanical properties, electrical properties, heat resistance, low hygroscopicity, processability, etc., and is an engineering plastic. Widely used as.

Attempts have already been made to blend AS resins with polyesters. For example, US Pat.
No. 22,854, JP-A-54-133547, JP-A-52-152448, and JP-A-58-162655, hot melt adhesives containing polybutylene terephthalate as a polyester, polybutylene terephthalate and polyether ester, respectively. A composition having improved paintability by blending with, a composition having excellent surface smoothness with polybutylene terephthalate and an inorganic filler, and the like are disclosed.

Further, US Pat. No. 4,987,187 discloses a composition of 5 to 35% by weight of AS resin and 95 to 5% by weight of polyester copolymerized with cyclohexanedimethanol.

[0006]

However, the conventional method does not disclose a composition which retains the excellent moldability and transparency of AS resin and improves the chemical resistance. Generally, blending AS resin with polyester is recognized to improve chemical resistance,
Since the compatibility between the two resins is insufficient, there are drawbacks that mechanical properties are deteriorated, a delamination phenomenon occurs, and transparency, which is a characteristic of the AS resin, is significantly impaired. further,
When a resin with high crystallinity is blended, the characteristics such as molding shrinkage change greatly with respect to the AS resin, so it may be necessary to renew the conventionally used mold. Has the drawback of being difficult to use.

The object of the present invention is to maintain the excellent basic characteristics represented by the transparency and molding processability of AS resin,
It is an object of the present invention to provide a resin composition having improved chemical resistance, which is a drawback of AS resin.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by combining an AS resin of a specific composition with a polyester, the AS resin has excellent transparency and moldability. Therefore, the inventors have found that a molded article having improved chemical resistance and excellent compatibility without deteriorating the molding shrinkage rate can be obtained without deteriorating the molding shrinkage, and that a molded article without delamination can be obtained.

That is, the present invention relates to vinyl cyanide (a)
And a total of aromatic vinyl (b) 100 to 80% by weight,
Other copolymerizable vinyl monomer (c) 0 to 20% by weight
A copolymer obtained by copolymerizing a monomer mixture consisting of
40 to 95 parts by weight and 60 to 5 parts by weight of an aromatic polyester resin (b), the main dicarboxylic acid component of which is an aromatic dicarboxylic acid, and cyclohexanedimethanol as a glycol component as an essential component. When the copolymerization weight fraction of vinyl cyanide in b) is x and the weight fraction of the segment composed of the cyclohexanedimethanol residue and the dicarboxylic acid residue of the aromatic polyester resin (b) is y, x , Y provides a thermoplastic resin composition satisfying the formula (I).

3.85x−1.0 ≦ y ≦ 3.85x−0.2 (I) The present invention will be specifically described below.

The copolymer (a) in the present invention is a copolymer composed of vinyl cyanide, aromatic vinyl, and optionally other copolymerizable monomers.

Examples of vinyl cyanide include acrylonitrile and methacrylonitrile.
Acrylonitrile is preferably used.

Examples of aromatic vinyl include styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene and the like. Among them, styrene and / or α-methylstyrene is preferably used.

As other copolymerizable monomers, methyl methacrylate, ethyl methacrylate, methacrylic acid-t-
Butyl, α-β-unsaturated carboxylic acid esters such as cyclohexyl methacrylate, unsaturated dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride or derivatives thereof, N-phenylmaleimide, N-methylmaleimide, N- Examples thereof include imide compounds of unsaturated dicarboxylic acid such as t-butylmaleimide.

The composition of the copolymer (a) includes vinyl cyanide (a) and aromatic vinyl (b) in the range of 100-80.
When it is defined as weight%, the other copolymerizable vinyl monomer (c) may be contained in the range of 0 to 20 weight%.

Further, the copolymer (a) has an intrinsic viscosity of 0.3.
Within the range of 1.3 to 1.3, a thermoplastic resin composition having further excellent chemical resistance, transparency and molding processability can be obtained. The intrinsic viscosity is a value measured at 30 ° C. using N, N-dimethylformamide.

Further, by setting the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight of the copolymer (a) to be 3.8 or less, a thermoplastic resin composition having more excellent transparency can be obtained. To be

There are no particular restrictions on the production of the copolymer (a), and generally known methods such as bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization and emulsion polymerization can be used.

The polyester used in the present invention is a copolymer whose main dicarboxylic acid component is an aromatic dicarboxylic acid and which contains cyclohexanedimethanol as an essential component as a glycol component.

The aromatic dicarboxylic acid constituting the polyester includes terephthalic acid, isophthalic acid, phthalic acid,
1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,
2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, 4,4 '
-Diphenylmethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-diphenyl isopropylidene dicarboxylic acid, 1,2-bis (phenoxy)
Ethane-4,4'-dicarboxylic acid, 2,5-anthracene dicarboxylic acid, 2,6-anthracene dicarboxylic acid,
4,4'-p-terphenylenedicarboxylic acid, 2,5-
Pyridine dicarboxylic acid and the like, terephthalic acid,
Isophthalic acid is particularly preferably used.

Two or more kinds of these aromatic dicarboxylic acids may be mixed. A small amount, usually about 30 mol% or less, together with these aromatic dicarboxylic acids, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids One or more types can be mixed and used.

The diol components other than cyclohexanedimethanol include ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol,
2-Methyl-1,3-propanediol, diethylene glycol, triethylene glycol and the like can be mentioned. Ethylene glycol is particularly preferably used as a diol component other than cyclohexanedimethanol.

The weight fraction y of the segment composed of the cyclohexanedimethanol residue and the dicarboxylic acid residue in the aromatic polyester resin of the present invention is represented by the formula (I).
It is the range shown in.

3.85x−1.0 ≦ y ≦ 3.85x−0.2 (I) (where x represents the copolymerization weight fraction of vinyl cyanide in the copolymer (a)). When y is less than or exceeds the range represented by the formula (I), transparency of the resulting thermoplastic resin composition is significantly impaired, which is not preferable.

In the thermoplastic resin composition of the present invention, the blending ratio of the copolymer (a) and the aromatic polyester resin (b) is 40 to 95 parts by weight, preferably 45 to 9 parts by weight.
0 parts by weight, more preferably 50 to 85 parts by weight,
(B) is 60 to 5 parts by weight, preferably 55 to 10 parts by weight, more preferably 50 to 15 parts by weight, and
The ratio is such that the total of (a) and (b) is 100 parts by weight. If (a) is less than 40 parts by weight, molding processability such as excellent fluidity of the AS resin is impaired, and if (b) is less than 5 parts by weight, the effect of improving chemical resistance to the AS resin is small, which is not preferable.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and a generally known method can be adopted. That is, the copolymer (a) and the aromatic polyester resin (b) are uniformly mixed in pellets, powder, fine particles, granules, etc. using a high-speed stirrer, etc., and then uniaxial or multi-axial with sufficient kneading ability. Various methods such as a method of melt-kneading with a shaft extruder and a method of melt-kneading with a Banbury mixer or a rubber roll machine can be adopted.

The molding resin composition of the present invention comprises, in addition to the copolymer (a) and the aromatic polyester resin (b), polystyrene, polymethyl methacrylate, polyphenylene ether, if necessary, within a range not impairing transparency. , Thermoplastic resin such as polycarbonate, polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / brene-1 Polyolefin rubbers such as polymers, ethylene / propylene / cyclopentadiene copolymers, ethylene / propylene / 5-ethylidene-2-norbornene copolymers, ethylene / vinyl acetate copolymers, ethylene / butyl acrylate copolymers More desirable physical properties and characteristics by mixing appropriately It is also possible to adjust.

Further, depending on the purpose, reinforcing materials and fillers such as pigments and dyes, glass fibers, metal fibers, metal flakes and carbon fibers, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants. , A plasticizer, an antistatic agent, a flame retardant and the like can also be added.

[0029]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples.

The intrinsic viscosity [η] was measured at 30 ° C. using N, N-dimethylformamide as a solvent.

Mw / Mn was measured using gel permeation chromatography (GPC).

The total light transmittance was measured using a disc having a thickness of 2 mm and a diameter of 10 mm. A direct-reading haze meter manufactured by Toyo Seiki Co., Ltd. was used for the measurement.

The lower limit of molding pressure, which is a measure of fluidity, was measured by measuring the lowest injection pressure required to fill the resin with a mold during injection molding, and compared with this.

For chemical resistance, the injection-molded square plate was immersed in methanol and gasoline at 23 ° C. for 24 hours, and the square plate surface was visually observed.

The molding shrinkage is ASTM D-955-
51 was measured.

The following parts and% represent parts by weight and% by weight, respectively, except for the total light transmittance (%).

Reference Example A copolymer (a) was produced according to the following formulation.

A-1: A monomer consisting of 75% styrene and 25% acrylonitrile was copolymerized by an emulsion polymerization method. The obtained AS copolymer is coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to obtain powdery AS.
A copolymer (A-1) was prepared. (X = 0.25,
[Η] = 0.512 dl / g, Mw / Mn = 2.5) A-2: A monomer consisting of 80% styrene and 20% acrylonitrile was copolymerized by an emulsion polymerization method. The obtained AS copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered, and dried to prepare a powdery AS copolymer (A-2). (X = 0.20, [η] = 0.
552 dl / g, Mw / Mn = 2.8) A-3: A monomer composed of 60% styrene and 40% acrylonitrile was copolymerized by an emulsion polymerization method. The obtained AS copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered, and dried to prepare a powdery AS copolymer (A-3). (X = 0.40, [η] = 0.
711 dl / g, Mw / Mn = 2.9) A-4: A monomer consisting of 70% styrene and 30% acrylonitrile was copolymerized by an emulsion polymerization method. The obtained AS copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered, and dried to prepare a powdery AS copolymer (A-4). (X = 0.30, [η] = 1.
515 dl / g, Mw / Mn = 2.2) A-5: A monomer consisting of 65% styrene and 35% acrylonitrile was copolymerized by an emulsion polymerization method. The obtained AS copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered, and dried to prepare a powdery AS copolymer (A-5). (X = 0.35, [η] = 0.
663 dl / g, Mw / Mn = 4.5) The following were used as the aromatic polyester (b).

B-1: An aromatic polyester resin comprising terephthalic acid as a dicarboxylic acid, 65 mol% of ethylene glycol and 35 mol% of 1,4-cyclohexanedimethanol as a diol component. (Y = 0.435) B-2: An aromatic polyester resin composed of terephthalic acid as a dicarboxylic acid and 46 mol% of ethylene glycol and 54 mol% of 1,4-cyclohexanedimethanol as a diol component. (Y = 0.626) B-3: An aromatic polyester resin composed of terephthalic acid as a dicarboxylic acid, 20 mol% of ethylene glycol and 80 mol% of 1,4-cyclohexanedimethanol as a diol component. (Y = 0.851) B-4: Polybutylene terephthalate resin (Toray Industries, Inc.)
Manufactured by PBT-1200L).

B-5: Polyethylene terephthalate resin (J-025 manufactured by Mitsui Pet Resin Co., Ltd.).

[0041]

Examples 1 to 12 Copolymers (a) A-1 to A-5 and aromatic polyesters (b) B-1 to B-3 produced in Reference Examples were mixed in the mixing ratio shown in Table 1. Then, it is extruded at an extrusion temperature of 260 ° C. by a 30 mmφ twin-screw extruder and pelletized, and then each pellet is subjected to injection molding under the conditions of a molding temperature of 250 ° C. and a mold temperature of 60 ° C. to prepare each test piece, The physical properties were evaluated.

Comparative Examples 1 to 7 The copolymers (a) A-1 to A-3 and the aromatic polyesters (b) B-1 to B-5 produced in Reference Examples were blended in the proportions shown in Table 1. After mixing and extruding with a 30 mmφ twin-screw extruder at an extrusion temperature of 260 ° C. and pelletizing each, each pellet was subjected to injection molding under the conditions of a molding temperature of 250 ° C. and a mold temperature of 60 ° C. to prepare each test piece. The physical properties were evaluated.

The following is clear from the examples and comparative examples. That is, each of the resin compositions obtained by the present invention has good transparency, excellent moldability and chemical resistance, and a molding shrinkage ratio substantially equal to that of the AS resin. On the other hand, when the polyester copolymer composition deviates from the copolymer composition represented by the formula disclosed in the present invention, the transparency of the composition is impaired. On the other hand, when the blending ratio of the resin composition exceeds the range of the present invention, the lower limit pressure for molding becomes high, and the moldability may be impaired. Further, the ABS resin alone has poor chemical resistance. A system using polybutylene terephthalate and polyethylene terephthalate as the polyester has drawbacks that transparency is lowered and molding shrinkage is large.

[0045]

[Table 1]

[0046]

EFFECTS OF THE INVENTION According to the present invention, a thermoplastic resin having excellent chemical resistance, transparency and compatibility between resins does not cause delamination of a molded product, has excellent moldability, and has a small molding shrinkage ratio. A composition is obtained.

Claims (4)

[Claims] 1. A monomer mixture comprising 100 to 80% by weight of vinyl cyanide (a) and aromatic vinyl (b) in total, and 0 to 20% by weight of other copolymerizable vinyl monomer (c). Aromatic polyester resin (b) 60 containing 40 to 95 parts by weight of a copolymer (a) obtained by copolymerization, an aromatic dicarboxylic acid as a main dicarboxylic acid component, and cyclohexanedimethanol as an essential component as a glycol component. A segment composed of cyclohexanedimethanol residues and dicarboxylic acid residues of the aromatic polyester resin (b), wherein x is the copolymerization weight fraction of vinyl cyanide in the copolymer (b), A thermoplastic resin composition in which x and y satisfy the formula (I), where y is the weight fraction of 3.85x-1.0≤y≤3.85x-0.2 (I) 2. The intrinsic viscosity of the copolymer (a) is 0.3 to
The thermoplastic resin composition according to claim 1, which is in the range of 1.3. 3. The thermoplastic resin composition according to claim 1, wherein the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight of the copolymer (a) is 3.8 or less. 4. The intrinsic viscosity of the copolymer (a) is 0.3 to
The thermoplastic resin composition according to claim 1, wherein the ratio is in the range of 1.3 and the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight is 3.8 or less.