JPH0362186B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition with excellent cold resistance containing polyalkylene terephthalate as a main component, and more specifically to a resin composition with improved cold resistance by blending polyalkylene terephthalate with a specific diene-based rubber graft copolymer. The present invention relates to a composition. Polyalkylene terephthalate resins, particularly polybutylene terephthalate and polyethylene terephthalate, are used for various purposes because they have excellent heat resistance, weather resistance, and chemical resistance. However, a serious drawback of this polyalkylene terephthalate is its low impact resistance, and various proposals have been made to improve it. For example, there have been proposals in JP-A-52-150466, JP-A-54-31456, and JP-A-57-94037 to mix an acrylic rubber-based graft copolymer with polyalkylene terephthalate. Japanese Patent Publication No. 51-25261, Japanese Patent Application Laid-open No. 57-94038, etc. have proposed methods for mixing graft copolymers mainly composed of rubber. The reason why various proposals have been made regarding graft copolymers of acrylic rubber or diene rubber is that even when blended with polyalkylene terephthalate, there is little improvement in impact resistance. This is because there are many cases in which no effects are observed, or even if improvements are made, they are not sufficient. For example, in Japanese Patent Publication No. 51-25261, it is stated that ABS resin with a high rubber content has an excellent impact resistance improvement effect, but MBS resin, which is generally commercially available and well-known,
It is said that such excellent effects cannot be obtained with resin. The present inventors took advantage of the excellent heat resistance and chemical resistance of polyalkylene terephthalate resin to
After conducting various studies to provide high impact resistance, especially cold resistance, which is required for electrical parts, it became clear that although various proposals have been made in the past, nothing satisfactory has yet been achieved. In light of this current situation, we have conducted extensive studies to improve the cold resistance of polyalkylene terephthalate resins, and have surprisingly discovered that diene-based rubber gluto copolymers produced by a specific method have not been thought to be sufficiently effective in improving impact resistance. Nevertheless, the present invention has been achieved by discovering that by blending this with polyalkylene terephthalate, it has a truly excellent effect of improving cold resistance and impact resistance. That is, the present invention relates to a butadiene-based elastomer containing 50% by weight or more of 1,3-butadiene as a constituent component.
(A) methyl methacrylate in the presence of 35 to 80 parts by weight;
12 to 57% by weight, (B) 1 to 24% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms,
(C) 80-40% by weight of styrene and (D) 0-3% by weight of a polyfunctional crosslinking agent having one or more allyl groups in the molecule.
When graft polymerizing 65 to 20 parts by weight of a monomer mixture consisting of 65 to 20 parts by weight, a polymer latex containing carboxyl groups is first added, and then the following amount of monomer (A) methacrylic acid is added as the first stage of grafting. Methyl 6-51.3% by weight (B) Acrylic acid alkyl ester having an alkyl group having 1-8 carbon atoms 0.5-21.6% by weight and (D) Multifunctional crosslinking agent having one or more allyl groups in the molecule 0- 3% by weight (however, (A)>(B)) is graft-polymerized, then in the second stage, styrene is graft-polymerized, and then in the third stage, the following monomer (A) methyl methacrylate is graft-polymerized. 3 to 45 parts by weight of a graft copolymer obtained by graft polymerization of 1.2 to 28.5% by weight and (B) 0.1 to 12.0% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, and a polyalkylene terephthalate resin 97 ~55 parts by weight of a resin composition with excellent cold resistance. Furthermore, the present invention contains 2 reinforcing fillers in the entire resin composition.
The present invention also provides a resin composition containing up to 50% by weight. The butadiene elastomer constituting the graft copolymer used in the present invention contains 50% by weight or more of 1,3-butadiene and monoolefin monomers such as acrylonitrile, styrene, acrylic acid alkyl ester, methacrylic acid alkyl ester, etc. It is obtained by polymerizing a polyfunctional monomer such as divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, etc. in an amount of 50% by weight or less and 2% by weight or less. Particularly preferably, the butadiene elastomer is 1,3-butadiene98
It is obtained by polymerizing ~100% by weight and 2~0% by weight of a polyfunctional monomer. A composition containing more than 2% by weight of a polyfunctional monomer is not preferred because the impact resistance of the final composition decreases. Further, the average particle diameter of the butadiene-based elastomer is preferably 0.12 μm or less. The particle size is
If it exceeds 0.12μ, it will take a long time to polymerize the elastomer, resulting in poor productivity and, on the other hand, it will not be possible to obtain a product with excellent cold resistance. In producing graft copolymers, it is particularly important to add a polymer latex containing carboxyl groups to the elastomer prior to graft polymerization. Polymer latexes containing carboxyl groups include 97 to 40% by weight of alkyl acrylates whose alkyl groups have 1 to 12 carbon atoms, 3 to 30% by weight of unsaturated acids that can be copolymerized with these, and vinyl compounds that can be copolymerized with these. A latex with a pH of 4 or higher containing a copolymer of 0 to 30% by weight (total 100% by weight), preferably n-butyl acrylate and methacrylic acid, ethyl acrylate and methacrylic acid, or n-butyl acrylate and acrylic acid. It is a latex made by emulsion copolymerization of monomers such as acids. The amount of the polymer latex containing carboxyl groups added is 0.01 to 100 parts by weight (as solid content) of the butadiene-based elastomer latex.
Added 10 parts by weight (as solids). By this addition, the rubber particles can be significantly enlarged, and at the same time large particle size rubber and small particle size rubber can coexist, which improves the cold resistance of the final composition and satisfies the maintenance of desirable rigidity and heat resistance. be able to. For example, just by adding 0.5% isomorphic content of the polymer latex, butadiene-based elastomer
It is possible to enlarge 0.07μ latex to a rubber particle size of 0.3μ or more, and in this case, the particle size distribution has a distribution in which a distribution with a center at 0.3μ or more and a distribution with a center at 0.1μ or less are overlapped. ing. In the presence of such enlarged latex, as a first stage, (A) 6 to 51.3% by weight of methyl methacrylate, (B) 0.5 to 21.6% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, (however,
(A)>(B)), (D) 0 to 3% by weight of a polyfunctional crosslinking agent having one or more allyl groups in the molecule is added and graft polymerized, and then styrene is grafted in the second stage. After polymerization, as a third stage, (A) methyl methacrylate corresponding to the remaining amount of the first stage 1.2 to 28.5
Weight% and (B) alkyl acrylate 0.1-12.0% by weight
obtained by graft polymerization. The amount of monomers used in such graft polymerization is 12 to 57% by weight of methyl methacrylate and 1 to 8 carbon atoms.
1 to 24% by weight of an acrylic acid alkyl ester having an alkyl group, 80 to 40% by weight of styrene, and 0 to 3% by weight of a polyfunctional crosslinking agent having one or more allyl groups in the molecule. It is essential to graft polymerize 50 to 90% by weight of the total amount of methyl methacrylate and alkyl acrylate in the first stage from the viewpoint of cold resistance and impact resistance, and then graft polymerize styrene in the second stage. Polymerize. Furthermore, in the present invention, it is necessary to graft-polymerize 10 to 50% by weight of the total amount of methyl methacrylate and acrylic acid alkyl ester in the third stage. If this amount is less than 10% by weight, impact resistance will decrease and residual styrene monomer will increase. Further, in the third stage, it is preferable to increase the amount of methyl methacrylate as much as possible and reduce the amount of alkyl acrylate. Examples of the polyfunctional crosslinking agent containing one or more allyl groups in the molecule include triallyl cyanurate, triallyl isocyanurate, allyl methacrylate, allyl acrylate, diallyl itaconate,
Diallyl phthalate and the like are used. The content of elastomer in the graft copolymer is
35-80% by weight, preferably 50-75% by weight. Generally known polymerization initiators, emulsifiers, etc. are used in the production of the graft copolymer of the present invention. More than 80 mol% of the polyalkylene terephthalate resin that is a component of the present invention has 2 to 2 carbon atoms.
A polyester consisting of a homopolymer, a copolymer, or a mixture of these polymers in which 80 mol% or more of alkylene glycol of No. 8 is condensed with terephthalic acid or its alkyl ester, and the copolymer contains less than 20 mol% of other dicarboxylic acids, e.g. It is a co-condensation product of isophthalic acid, halogenated terephthalic acid, poly(alkylene glycol), etc. Preferred polyalkylene terephthalate resins are polyethylene terephthalate,
It is polytetramethylene terephthalate. The blending ratio of the graft copolymer and polyalkylene terephthalate resin is graft copolymer 3.
-45 parts by weight of polyalkylene terephthalate resin (97-55 parts by weight total). If the amount of the graft copolymer added is less than 3 parts by weight, the effect of improving cold resistance will be insufficient, and if it exceeds 45 parts by weight, the excellent heat resistance and mechanical properties of the polyalkylene terephthalate resin will be impaired, which is not preferable. The resin composition of the present invention further contains a reinforcing filler in an amount of 2 to 50% by weight based on the total resin composition for the purpose of reinforcing the resin composition.
It can be made to contain. As the reinforcing filler, various types and shapes can be used. For example, fibrous, plate-like (flake-like), spherical, granular, etc. shapes are used, and specifically, glass fibers, carbon fibers, metal fibers,
Asbestos, potassium titanate, whiskers, ceramic fiber, milled fiber, glass powder, glass beads, glass foil (flake), talc, clay, kaolin, calcium carbonate, calcium metasilicate, processed mineral fiber, dawsonite, silica powder, quartz powder , mica, metal powder,
Titanium oxide, lithopone, carbon black, graphite, boron chloride, antimony trioxide, sodium antimonate, etc., and one or two of these
More than one species is used. Fibrous fillers have a large effect on improving mechanical properties, and can be shaped into flakes, spheres, plates, etc.
The granular filler has the effect of improving rigidity and heat resistance. When these and a fibrous filler are used together, the warpage of the molded product can be reduced more than when the fibrous filler is used alone. If the amount of such reinforcing filler added is less than 2% by weight, the reinforcing effect will be insufficient, and if it exceeds 50% by weight, the appearance of the molded product will deteriorate, reducing its commercial value. The reinforcing filler used in the present invention is preferably one that has been subjected to an appropriate surface treatment,
A well-known silane coupling agent,
Commercially available fillers such as surface-treated fillers such as titanate coupling agents and fillers treated with fatty acids can be used as they are or after surface treatment. The composition of the present invention may optionally contain stabilizers against light or heat such as ultraviolet absorbers and antioxidants, known modifiers such as epoxy resins and fatty acid ester waxes, mold release agents, fluidity improvers, and bromine. Additives such as flame retardants such as chemically modified epoxy and dyes and pigments can be added. The present invention will be explained in detail below with reference to Examples. Example 1 Synthesis of graft copolymer (1) Synthesis of rubber latex (A-1) 1,3-butadiene 100 parts by weight Sodium laurate 4 n-lauryl mercaptan 0.5 Potassium persulfate 0.4 Deionized water 180 Above at 60℃ in a pressure autoclave according to the composition.
Rubber latex (average particle size
0.09μ) was obtained. (2) Synthesis of latex for enlargement (B-1) and preparation of latex for enlargement Ethyl acrylate Part by weight Methacrylic acid 10 〃 Potassium persulfate 0.5 〃 Nonsal TK-1 (manufactured by NOF Corporation) 2 〃 Rapizol 80 (〃 ) 1 〃 Water 200 parts by weight The above composition was polymerized at 70°C for 4 hours to obtain a latex (B-1) with a pH of 5.9. Put 100 parts by weight (solid content) of rubber latex (A-1) into a reaction vessel equipped with a stirrer and add 0.8 parts by weight (solid content) of latex (B-1) while stirring.
Added in 10 seconds. The particle size of the latex after stirring for 3 minutes had an average particle size of 0.3 microns, and showed enlarged particle sizes with many particles having a diameter of 0.6 microns to 0.4 microns. (3) Synthesis of graft copolymer Add 0.15 parts by weight of Rongalit as a reducing agent to 65 parts by weight (solid content) of the enlarged latex.
At 70°C, a mixture of 10 parts by weight of methyl methacrylate and 3 parts by weight of butyl acrylate to which 0.08 parts by weight of kyumene hydroperoxide (CHP) was added was continuously added dropwise over 1 hour, and after holding for another 1 hour, a second 18 parts by weight of styrene as the stage
A mixture of 0.12 parts by weight of CHP was added dropwise over 1 hour and held for an additional 2 hours. Then, in the third stage, a mixed solution of 4 parts by weight of methyl methacrylate and 0.02 parts by weight of CHP was added dropwise over 15 minutes and held for 1 hour to complete the polymerization. 0.5 parts by weight of butylated hydroxytoluene (BHT) was added to the obtained latex, coagulated with a 0.2% aqueous sulfuric acid solution, and washed with warm water.
It was dried to obtain a graft copolymer (G-1). Comparative Example 1 Instead of adding the enlargement latex (B-1) to the rubber latex (A-1) of Example 1, 0.4% and 0.5% of dioctylsulfonesodium succinate were added, respectively.
Aqueous sulfuric acid solution was added little by little to lower the pH to 4.7. The average particle diameter of the obtained latex was 0.3μ. This rubber was stabilized by adding 2% potassium oleate, and in the presence of 65 parts by weight of this rubber, 10 parts by weight of methyl methacrylate and 3 parts by weight of butyl acrylate were first graft-polymerized in the first stage, and then In the second stage, 18 parts by weight of styrene is graft-polymerized,
In the third stage, 4 parts by weight of methyl methacrylate was graft-polymerized to obtain a graft copolymer latex. This latex was solidified in the same manner as in Example-1.
After washing and drying, a graft copolymer (CE-1) was obtained. Example 2 Graft copolymer synthesized in Example 1 (G-
1) and polytetramethylene terephthalate with an intrinsic viscosity [η] of 1.20 were weighed in the proportions shown in Table 1, and V
After mixing in a mold blender, the mixture was melt mixed and extruded using a 65φ vent extruder at a cylinder temperature of 230 to 260°C and shaped into pellets to obtain the resin composition of the present invention. These resin compositions were molded using a famous SJ 35B injection molding machine at a cylinder temperature of 250°C and a mold temperature of 60°C to obtain various molded products for evaluation. The evaluation results of these cold resistance etc. are shown in Table 1. Comparative Example-2b is the graft copolymer (G
It was obtained and evaluated in exactly the same manner as in this example except that the graft copolymer (CE-1) synthesized in Comparative Example-1 was used instead of -1). As is clear from Table 1, the graft copolymer (G-
The molded product obtained from the composition of the present invention using 1) shows excellent cold resistance, whereas the molded product using the graft copolymer (CE-1) as in Comparative Example-2b and the molded product obtained from the composition of the present invention using Comparative Example-2b -2c, which uses commercially available MBS resin, has the same rigidity but does not have sufficient cold resistance.

[Table] Example 3 In the above Example-2c, instead of 70 parts by weight of polytetramethylene terephthalate, the intrinsic viscosity [η] was
Using a total of 70 parts by weight of 40 parts by weight of polyethylene terephthalate with a concentration of 0.88 and 30 parts by weight of polytetramethylene terephthalate with [η] of 1.05, the extrusion temperature was adjusted to 240°C.
Melt mixing extrusion at ~270℃, others are Example-2c
A composition of the present invention was obtained in exactly the same manner. The cold resistance of this material was measured by Izotnotch impact strength at -30°C and was found to be 12.5 Kgcm/cm, which was good. Example 4 Polytetramethylene terephthalate with an intrinsic viscosity [η] of 0.95, the graft copolymer of Example 1 (G
-1), each filler shown in Table 2 as a reinforcing filler was weighed in the proportion shown in Table 2, and the composition of the present invention was obtained in exactly the same manner as in Example 2, and a molded article for evaluation was also obtained. . These evaluation results are shown in Table 2. The molded article obtained from the reinforced resin composition of the present invention showed good cold resistance. In addition, the enlarged latex in Example 1 was
30 parts by weight of the remaining graft monomer, 20 parts by weight of methyl methacrylate and 10 parts by weight of butyl acrylate as the first stage, 38 parts of styrene as the second stage, and methacrylate as the third stage. 20 parts by weight of a graft copolymer obtained by graft polymerization with 2 parts by weight of methyl acid was melt-mixed with 80 parts by weight of polytetramethylene terephthalate, but sufficient impact resistance was not exhibited. That is, it is important that the ratio of each component of the graft copolymer is within a specific range.

【table】

Claims (1)

[Scope of Claims] 1. In the presence of 35 to 80 parts by weight of a butadiene-based elastomer containing 50% by weight or more of 1,3-butadiene as a constituent component, (A) 12 to 57% by weight of methyl methacrylate, (B) carbon 1 to 24% by weight of acrylic acid alkyl ester having 1 to 8 alkyl groups, (C) styrene
When graft polymerizing 65 to 20 parts by weight of a monomer mixture consisting of 80 to 40% by weight and (D) 0 to 3% by weight of a polyfunctional crosslinking agent having one or more allyl groups in the molecule, the carboxyl group is A polymer latex containing methacrylate is added, and then, as the first stage of grafting, the following amounts of monomers (A) methyl methacrylate 6 to 51.3% by weight (B) acrylic having an alkyl group having 1 to 8 carbon atoms are added. 0.5 to 21.6% by weight of an acid alkyl ester and (D) 0 to 3% by weight of a polyfunctional crosslinking agent having one or more allyl groups in the molecule (wherein (A)>(B)) are graft-polymerized, and then After graft polymerizing styrene in the second stage, the following monomers (A) 1.2 to 28.5% by weight of methyl methacrylate and (B) acrylic having an alkyl group having 1 to 8 carbon atoms are added in the third stage. A resin composition with excellent cold resistance comprising 3 to 45 parts by weight of a graft copolymer obtained by graft polymerizing 0.1 to 12.0% by weight of an acid alkyl ester and 97 to 55 parts by weight of a polyalkylene terephthalate resin. 2. The resin composition according to claim 1, which contains 2 to 50% by weight of reinforcing filler in the total resin composition. 3 Butadiene elastomer contains 98-100% by weight of 1,3-butadiene and 2-0% by weight of polyfunctional monomer.
3. The resin composition according to claim 1 or 2, which is obtained by polymerizing the following.