JPH05339450A - Synthetic resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition, capable of improving the molding processability and having satisfactory properties especially as a lining sheet for electric refrigerators without impairing mechanical characteristics in spite of the fluorocarbon resistance maintained at a high level. CONSTITUTION:The objective resin composition is composed of 100 pts.wt. resin composition composed of (A) 5-80 pts.wt. graft copolymer comprising 30-95wt.% rubber polymer and 5-70wt.% vinyl cyanide compound and aromatic vinyl compound which are grafting components at 0.35-0.8 weight ratio of the [vinyl cyanide compound/(vinyl cyanide compound + aromatic vinyl compound)] and (B) 20-95 pts.wt. vinyl copolymer composed of 35-80wt.% vinyl cyanide compound and 20-65wt.% aromatic vinyl compound and/or (meth)acrylic acid ester compound and (C) 0.1-20 pts.wt. aliphatic polyester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a resin composition having excellent chlorofluorocarbon resistance and having sufficient properties as a resin composition for a sheet, and in particular, having a property satisfying as a lining sheet for an electric refrigerator. And a resin composition having the same.

[0002]

2. Description of the Related Art As a resin used as a material for an electric refrigerator inner box, it has relatively good chemical resistance like ABS resin, has sufficient mechanical strength, and has an appropriate working fluidity. Is required.

The electric refrigerator has a structure in which a space between the outer box and the inner box is filled with a foamed polyurethane heat insulating layer, and the resin material used for the inner box is not affected by CFC, a foaming agent for urethane foaming. Is required. As a method for satisfying such properties, Japanese Patent Laid-Open No. 2-284
As in the technique disclosed in Japanese Patent Publication No. 906, in order to improve the chemical resistance, it is common to increase the acrylonitrile content in the resin as compared with ordinary ABS, but the acrylonitrile content in the resin is If the amount is greatly increased, there are problems in production such as a decrease in color tone and an increase in gelation reaction.

On the other hand, as another method for improving the CFC resistance, there is a method in which another resin having excellent chemical resistance is blended with the ABS resin and used, and a method in which an ethylene-vinyl acetate copolymer is blended (special (Kaihei 3-292112), a method of blending a thermoplastic polyester elastomer (Japanese Patent Laid-Open No. 4-132762), and the like are known.

[0005]

The method of blending the resins as described above has a drawback that it is difficult to obtain a desired molded article because the compatibility of both resins is inherently poor.
Therefore, it has excellent compatibility, mechanical strength, and moldability,
Moreover, a resin material having excellent chlorofluorocarbon resistance is required.

[0006]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a method for improving molding processability without impairing mechanical properties while maintaining a high level of freon resistance was obtained.
The inventors have found that the above object can be achieved by using a resin composition comprising a graft copolymer having a high vinyl cyanide compound content and an aliphatic polyester, and have reached the present invention. Unlike the thermoplastic polyester elastomer, the aliphatic polyester has an excellent affinity with the above graft copolymer, and is characterized in that it does not impair mechanical properties, appearance, and the like.

That is, the present invention relates to a graft copolymer (A) in which a vinyl cyanide compound and an aromatic vinyl compound are grafted onto a rubber-like polymer, wherein the rubber-like polymer is 30 to 95% by weight. The component is 5 to 70% by weight, and the weight ratio of vinyl cyanide compound / (vinyl cyanide compound and aromatic vinyl compound) is 0.
5 to 80 parts by weight of the graft copolymer having a range of 35 to 0.8, and 35 to 80% by weight of the vinyl cyanide compound (B).
And 100 parts by weight of a resin composition comprising 20 to 95 parts by weight of a vinyl copolymer comprising 20 to 65% by weight of an aromatic vinyl compound and / or a (meth) acrylic acid ester compound, and (C) an aliphatic polyester 0.1. It is a resin composition consisting of 20 parts by weight.

The present invention will be described in detail below. Examples of the vinyl cyanide compound used in the present invention include acrylonitrile and methacrylonitrile. Particularly preferred is acrylonitrile. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, and paramethylstyrene.

The rubbery polymer has a glass transition temperature of 0 ° C. or lower, preferably -20 ° C. or lower. Specifically, polybutadiene, styrene-butadiene copolymer rubber, diene rubber such as acrylonitrile-butadiene copolymer rubber, acrylic rubber such as polybutyl acrylate,
Block copolymers such as polyisoprene, polychloroprene, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, styrene-butadiene block copolymer rubber, styrene-isoprene block copolymer rubber, and hydrogenated products thereof. Can be used. Preferred are polybutadiene, styrene-butadiene copolymer rubber, and acrylonitrile-butadiene copolymer rubber.

The proportion of the rubber-like polymer in the graft copolymer (A) is used in the range of 30 to 95% by weight, but it is preferably 50 from the viewpoint of the balance between impact resistance and working fluidity.
To 90% by weight. Further, the proportion of the graft component needs to be 5 to 70% by weight. 5% by weight
If less than, compatibility with the matrix resin decreases,
It is not preferable because the rubbery polymer agglomerates and the surface gloss of the resin decreases. On the other hand, if it exceeds 70% by weight, the impact resistance of the resin decreases, which is not preferable. A more preferable range is 10 to 50% by weight, and further preferable is 2
It is 0 to 60% by weight.

The ratio of the rubbery polymer to the graft component in the graft copolymer is specifically measured by dissolving the polymer produced by the polymerization in acetone and separating and removing the insoluble matter by a centrifuge. You can
The component that dissolves in acetone is the component that did not undergo graft reaction in the copolymerized polymer (non-graft polymer), and the value obtained by subtracting the amount of rubber polymer from the acetone insoluble content is defined as the value of the graft component. To be done.

The ratio of the copolymerization component in the graft copolymer (A) must be such that the value of vinyl cyanide compound / (vinyl cyanide compound + aromatic vinyl compound) is 0.35 to 0.8. is there. If it is less than 0.35, sufficient chemical resistance cannot be obtained. On the other hand, when it exceeds 0.8, the cyclization reaction and the cross-linking reaction of the vinyl cyanide compounds proceed at the time of high temperature processing, which is not preferable. More preferably 0.
The range is 35 to 0.6, and more preferably 0.4 to
It is in the range of 0.5.

Examples of the (meth) acrylic acid ester compound in the vinyl copolymer (B) include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate. Butyl acrylate is particularly preferred.

The proportion of vinyl cyanide compound in the vinyl copolymer (B) must be in the range of 35 to 80% by weight. If it is less than 35% by weight, sufficient CFC resistance cannot be obtained. If it exceeds 80% by weight, the cyclization reaction and the crosslinking reaction of the vinyl cyanide compounds proceed unfavorably during high temperature processing. More preferably 35-
It is in the range of 60% by weight, more preferably 40 to 50.
It is in the range of% by weight.

The preferred molecular weight of the vinyl copolymer (B) is in the range of 3 to 20 centipoise when the viscosity at 25 ° C. is measured using a methyl ethyl ketone solvent at a polymer concentration of 10% by weight.

The copolymer (B) may contain a non-graft polymer component produced during the production of the graft copolymer (A). However, the composition and the content of the non-graft polymer component derived from the graft copolymer (A) are as follows even if it is contained in the copolymer (B).
It is necessary that it is within the range of the above-mentioned copolymer (B) as a whole.

Examples of the (C) aliphatic polyester in the present invention include polyesters of adipic acid and alkylene glycol such as polycaprolactone, polyethylene adipate, and polybutylene adipate; polyesters of succinic acid and alkylene glycol such as polyethylene succinate; Polyesters of sebacic acid and alkylene glycol such as butylene sebacate and polyesters of dicarboxylic acid such as polycyclohexane dimethylene succinate and cyclohexane dimethylene glycol are typically used, and polycaprolactone is particularly preferable.

The aliphatic polyester has a molecular weight of 20.
Those in the range of 00 to 500,000 are used. Particularly preferably 10,000 to 15,000 from the mechanical properties of the resin.
The range is 0. The blending ratio of the polymers (A), (B) and (C) is such that (C) is in the range of 0.1 to 20 parts by weight when the total amount of (A) and (B) is 100 parts by weight. It is necessary to be.

First, the mixing ratio of (A) and (B) is
Determined according to the required resin properties, (A) +
When (B) is 100 parts by weight, it is necessary that (A) is in the range of 5 to 80 parts by weight in order to obtain a balance of mechanical properties. Next, when the amount of (C) added to 100 parts by weight of (A) + (B) is less than 0.1 parts by weight, the effect of improving the CFC resistance and molding processability is not sufficient, and 2
If the amount exceeds 0 parts by weight, the compatibility of the resin decreases and peeling of the molded piece occurs, which is not preferable. A more preferable range is 0.5 to 10 parts by weight.

The method for producing the resin composition in the present invention is not particularly limited, and the resin composition can be produced by an ordinary method, for example, melt blending by kneading with an extruder. At this time, it is possible to add usual additives such as an antistatic agent, an antioxidant, an ultraviolet absorber, a flame retardant, a pigment, a dye and a lubricant, if necessary.

[0021]

According to the present invention, as is clear from the physical properties shown in the following examples, a synthetic resin composition excellent in molding processability and CFC resistance while maintaining mechanical properties is provided.

[0022]

EXAMPLES In order to explain the present invention more specifically, examples and comparative examples will be described below, but these do not limit the present invention. (Hereinafter, "part" means "part by weight".)

Examples 1 to 4 and Comparative Examples 1 to 4 [Method for producing graft copolymer] (Graft copolymer A-1) 40 parts of polybutadiene rubber latex (weight average particle diameter 3000Å) and 100 parts of deionized water. And 1.5 parts of potassium rosinate were added and the gas phase was replaced with nitrogen, and the temperature was raised to 70 ° C. Then, a monomer mixture liquid consisting of 27 parts of acrylonitrile, 33 parts of styrene, 0.6 part of tertiary edyl decyl mercaptan and 0.1 part of cumene hydroperoxide, and 50 parts of deionized water and 0.2 parts of sodium formaldehyde sulfoxylate.
Solution, 0.004 parts of ferrous sulfate and 0.04 parts of ethylenediaminetetraacetic acid disodium salt were added over 7 hours, and the reaction was completed at a polymerization temperature of 70 ° C.

The content of acrylonitrile units in the components excluding the rubbery polymer determined by an infrared spectrophotometer is 4
It was 3%. This graft copolymer latex is salted out and dehydrated, and then dried to obtain powdered graft copolymer A-1.
Got

The graft copolymer A-1 contained 58% by weight of acetone-insoluble matter and 42% by weight of acetone-soluble matter. When the composition of the acetone insoluble matter in the graft copolymer was measured by an infrared spectrophotometer, the content of the rubber polymer was 69% by weight, the content of the graft component was 31% by weight, and the ratio of the acrylonitrile unit was Was 0.43. This acetone insoluble matter is referred to as a graft copolymer I.

(Graft copolymer A-2) Graft copolymer A-2 was prepared in the same manner as graft copolymer A-1, except that 17 parts of acrylonitrile and 43 parts of styrene in the monomer mixture were used. -2 was obtained. The content of acrylonitrile units in the components excluding the rubber-like polymer determined by an infrared spectrophotometer was 27%.

The content of acetone insoluble in the graft copolymer A-2 was 60% by weight, and the content of soluble in acetone was 40% by weight. When the composition of the acetone insoluble matter in the graft copolymer was measured by an infrared spectrophotometer, the content of the rubber polymer was 70% by weight, the content of the graft component was 30% by weight, and the ratio of the acrylonitrile unit was Was 0.27. This acetone insoluble matter is referred to as a graft copolymer II.

(Copolymer B-1) An AS resin (acrylonitrile-styrene copolymer) having a solution viscosity of 10 centipoise and an acrylonitrile content of 40 parts in the resin. (Copolymer B-2) A terpolymer having a solution viscosity of 12 centipoise, an acrylonitrile content of 43 parts in the resin, butyl acrylate of 11 parts, and styrene of 46 parts. (Copolymer B-3) AS resin (acrylonitrile-styrene copolymer) having a solution viscosity of 11 centipoise and an acrylonitrile content in the resin of 27 parts. (Aliphatic polyester C-1) Weight average molecular weight 7,000
It was set to C-1 using the polycaprolactone of 0. (Aliphatic polyester C-2) Weight average molecular weight 1500
It was set to C-2 using the polycaprolactone of 00.

The above resins were blended in the composition shown in Table 1 and kneaded and granulated by a twin-screw extruder having a cylinder temperature of 240 ° C. Then, a test piece for measuring physical properties was obtained by injection molding at a molding temperature of 240 ° C. Table 2 shows the measurement results of these physical properties. It is apparent from the above examples that the one to which the aliphatic polyester is added is excellent in molding processability and chlorofluorocarbon resistance while maintaining the mechanical properties.

(Measurement Method) Melt Flow Rate (MFR) Based on JIS K-7210. Impact strength (1/4 IzoD): ASTM D-2
Based on 56. Flexural Modulus (FM): Based on ASTM D-790. CFC resistance Cover the center of compression-molded and annealed test piece (width 12.7 mm x thickness 1.0 mm) with gauze and the outside with Saran wrap, and apply a load of 0.75% to the test piece. After the application, Freon 141b was injected with a syringe to perform a creep test, and the time from the injection to the break of the test piece was measured. Freon 1 sometimes to prevent the gauze from drying during the test
41b was injected, and the time (seconds) until fracture was measured. Peelability: The fractured surface of the sample after the IzoD impact strength measurement was visually observed to determine the peeled state. ◯: Peeling is not seen ×: Peeling is seen

[0031]

[Table 1]

[0032]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 55/02 LMF 7142-4J F25D 23/06 T 7380-3L // (C08L 33/18 55: 02 67:02)

Claims (3)

[Claims] 1. A graft copolymer obtained by grafting (A) a vinyl cyanide compound and an aromatic vinyl compound onto a rubber polymer, wherein the rubber polymer is 30 to 95% by weight.
And the graft component is 5 to 70% by weight, and the weight ratio of vinyl cyanide compound / (vinyl cyanide compound and aromatic vinyl compound) is 0.35 to 0.8. A vinyl copolymer 20-9 comprising 5 to 80 parts by weight of the combined product and (B) 35 to 80% by weight of a vinyl cyanide compound and 20 to 65% by weight of an aromatic vinyl compound and / or a (meth) acrylic acid ester compound.
A resin composition comprising 100 parts by weight of a resin composition consisting of 5 parts by weight and 0.1 to 20 parts by weight of (C) an aliphatic polyester. 2. A sheet molded article obtained by using the resin composition according to claim 1. 3. An inner box for an electric refrigerator, which comprises the sheet molded product according to claim 2.