JP2001329132A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material that can minimize the reduction of transmitted light, even when it absorbs water and has excellent impact strength and surface resistivity. SOLUTION: The objective thermoplastic resin composition comprises polymer components (A), (B) and (C) wherein the component (A) includes (a-1) 30-70 pts.wt. of an acrylic resin, (a-2) 30-70 pts.wt. of a copolymer obtained by grafting a vinyl cyanide and an aromatic vinyl onto a rubber polymer and (a-3) 0-30 pts.wt. of a copolymer of a vinyl cyanide and an aromatic vinyl and the component (B) consists of 5-30 pts.wt. of a specific elastomer and the component (C) 0-10 pts.wt. of at least one of organic and inorganic electrolytes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition in which transmitted light is hardly reduced even when water is absorbed.

[0002]

2. Description of the Related Art In recent years, transparent plastics have been used in large quantities. However, since they are electrically poor conductors, they often cause troubles and dust caused by static electricity. For this reason, it is considered that plastics are given antistatic properties. For the transparent resin, for example, polymethyl methacrylate (PMMA), methyl methacrylate-butadiene styrene copolymer (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS / transparent ABS) and the like are currently frequently used. Have been. However, the antistatic properties of these resins are low, and there have been claims that electrostatic damage (malfunction of ICs, etc.), adhesion of dust, and the like occur. However, there was no transparent resin having all of the antistatic performance, transparency, water absorption whitening, and impact properties.

As a method of imparting antistatic properties to the transparent resin, a method has been proposed in which the refractive index of the rubbery polymer and the refractive index of the resin of the matrix are made substantially equal. An example is shown below. (1) JP-A-55-36237, JP-A-63-63
No. 63739: A method in which a vinyl copolymer having a polyoxyethylene chain and a sulfonate, carboxylate or quaternary ammonium salt structure is kneaded with an acrylic resin. (2) JP-A-1-308444: Acrylic resin contains a polyamide elastomer and at least one of a carboxyl group, an epoxy group, an amino group and a hydroxyl group.
A permanent antistatic resin with excellent surface gloss without delamination by adding a modified vinyl polymer containing various functional groups and, if necessary, a rubber graft copolymer.

(3) JP-A-63-309552,
JP-A-63-31342: Report on impact-resistant and transparent thermoplastic resin using polyetheresteramide. (4) JP-A-63-200837: Report on impact-resistant and transparent thermoplastic resin using polyetheresteramide (TPA) having low crystallinity. (5) JP-A-06-100747 and JP-A-08-100747
No. 59948: Report on a transparent antistatic resin obtained by melt-mixing an acrylic resin, an AS resin, and TPA. (6) JP-A-8-120147: A report on a transparent antistatic resin in which TPA having reduced crystallinity is dispersed in an acrylic resin.

However, many of these reported polymer antistatic agents (for example, polyetheresteramide) have a high water absorption, and the light transmittance changes at high temperature and high humidity (water absorption and whitening). There were many. There has been no example in which transparent and sufficient impact resistance, antistatic property and low water absorption are achieved.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a high-impact, long-lasting antistatic resin which does not lose its transparency due to water absorption.

[0007]

Means for Solving the Problems The inventor of the present invention has studied to solve the above-mentioned problems and arrived at the present invention. That is, in the present invention, the component (A) comprises (a-1) an acrylic resin 30 to
70 parts by weight, (a-2) a graft copolymer 30 obtained by grafting vinyl cyanide and aromatic vinyl onto a rubbery polymer
70 to 70 parts by weight, and (a-3) a transparent matrix resin 70 to 5 to 40 parts by weight of a rubbery polymer obtained by mixing 0 to 30 parts by weight of a copolymer of vinyl cyanide and aromatic vinyl. 95 parts by weight, component (B), refractive index 1.51 to
1.54, a thermoplastic elastomer 5 having a water absorption at 23 ° C. of 100% by weight or less and a surface resistivity of 1 × 10 ¹¹ Ω or less
-30 parts by weight (provided that the difference in the refractive index between the matrix resin containing the rubbery polymer as the component (A) and the thermoplastic elastomer as the component (B) is 0.02 or less), and the component (C) is an organic electrolyte And at least one selected from inorganic electrolytes
A thermoplastic resin composition comprising 0 to 10 parts by weight of a seed.

The (A-1) acrylic resin of the component (A) of the present invention is a methyl methacrylate homopolymer and a methyl methacrylate copolymer containing not more than 15% by weight of a methyl acrylate unit or an ethyl acrylate unit. Among them, preferred is a methyl methacrylate copolymer containing 85 to 99% by weight of methyl methacrylate units and 15 to 1% by weight of methyl acrylate units or ethyl acrylate units. Normally methyl methacrylate polymer (PMMA), methyl acrylate polymer (PMA)
Can be used.

The component (A) (a-2) of the present invention is a rubbery polymer, a graft copolymer of vinyl cyanide and aromatic vinyl. As the rubbery polymer of the present invention,
Polybutadiene, polyisoprene, diene rubber such as styrene-butadiene copolymer, ethylene-propylene rubber as ethylene α-olefin rubber, non-diene rubber such as ethylene-butene rubber, acrylate rubber, methacrylate rubber, Silicon acrylic rubber and the like can be mentioned.

The vinyl cyanide of the present invention includes acrylonitrile, methacrylonitrile and the like, and acrylonitrile is preferably used. Examples of the aromatic vinyl of the present invention include styrene and α-methylstyrene such as α-methylstyrene.
-Substituted styrene, vinyltoluene, m-, p-chlorostyrene and the like, one or more of these are used, and styrene is most preferred. Typically, an ABS resin obtained by polymerizing acrylonitrile and styrene on polybutadiene is a typical example.

The rubbery polymer, vinyl cyanide and aromatic vinyl of the present invention are produced by known bulk polymerization, suspension polymerization and emulsion polymerization. Component (A-3) of the present invention (A-3)
Is a copolymer of vinyl cyanide and aromatic vinyl. The above-mentioned vinyl cyanide and aromatic vinyl are used, but an AS resin obtained by polymerizing acrylonitrile and styrene is preferably used as a typical example.

The (a-4) acid-modified or epoxy-modified resin of the component (A) of the present invention is the above-mentioned (a-1),
It is a resin obtained by partially modifying (a-2) and (a-3) with acid or epoxy as long as compatibility with the matrix resin is not impaired. There is no particular limitation on the monomer used for the copolymer of the acid-modified resin, but it must maintain transparency (total light transmittance of 60% or more) when mixed with the matrix resin. For example, the (a-
1) A resin obtained by copolymerizing a vinyl monomer containing a carboxyl group in a resin, and (a-3) a resin obtained by copolymerizing a vinyl monomer containing a carboxyl group in the resin.

Examples of the vinyl monomer having a carboxyl group include unsaturated compounds having a free carboxyl group such as acrylic acid, crotonic acid, cinnamic acid, itaconic acid and maleic acid, maleic anhydride, and maleic anhydride. Examples thereof include unsaturated compounds containing an acid anhydride type carboxyl group such as itaconic acid, chloromaleic anhydride and citraconic anhydride, and among these, acrylic acid, methacrylic acid and maleic anhydride are preferred. Other modifications include copolymers of monomers having a sulfonic acid, glycidyl group or the like as a functional group.

The component (B) of the present invention has a refractive index of 1.51.
１．５1.54, the saturated water absorption at 23 ° C. is 100% by weight or less,
It is a thermoplastic elastomer having a surface resistivity of 1 × 10 ¹¹ Ω or less. If the refractive index is less than 1.51, it is difficult to obtain a thermoplastic elastomer having the above conditions. On the other hand, if the refractive index exceeds 1.54, the raw material of the thermoplastic elastomer becomes expensive and has a yellowish color. The refractive index is more preferably 1.51 to 1.53.

The saturated water absorption at 23 ° C. is desirably as low as possible. If it exceeds 100% by weight, the resin composition of the present invention discolors at the time of absorbing water and the total light transmittance decreases. The water absorption is more preferably 80% by weight or less. The surface resistivity of the elastomer may as low, 1 × 10 ¹¹
If it exceeds Ω, only those having high surface resistivity of the resin composition of the present invention can be obtained, and the object of the present invention cannot be achieved. It is particularly preferable to use a polyetheresteramide prepared from bisphenol A ethylene oxide adduct described in JP-A-8-120147, but other JP-A-1-144417, Showa 6
Among the polyetheresteramides described in JP-A-3-309552, JP-A-63-31342, JP-A-6-100747, etc., those having a low water absorption can be used.

The present invention relates to a thermoplastic elastomer having a low water absorption and a low surface resistivity, as described above, and a matrix resin containing a rubbery polymer having a specific refractive index. The components (A) and (D) of the present invention are transparent resins containing 5 to 40 parts by weight of a rubbery polymer. However, if the amount of the rubbery polymer is 5 parts by weight or less, there is a problem in impact resistance. When the amount is more than 40 parts by weight, the rigidity of the thermoplastic resin composition obtained by mixing becomes low and the transparency is poor. More preferably, the rubbery polymer is contained in an amount of 10 to 30 parts by weight.

Preferred examples of the component (D) of the present invention include a graft copolymer using butadiene rubber having a refractive index of 1.51 to 1.53. In the present composition, to further improve its antistatic performance,
As the component (C), dodecylbenzenesulfonic acid, p-
Aromatic sulfonic acids such as toluene sulfonic acid, dodecyl diphenyl ether disulfonic acid, naphthalene sulfonic acid, condensates of naphthalene sulfonic acid and formalin; alkyl sulfonic acids such as lauryl sulfonic acid; stearic acid, lauric acid, and organic acids such as polyacrylic acid carboxylic acid,
At least one selected from organic phosphoric acids such as diphenyl phosphite and diphenyl phosphate, and alkali metal salts and alkaline earth metal salts thereof can be used.

Of these, alkali metal salts and alkaline earth metal salts are preferred, and sodium salts and potassium salts are particularly preferred. The amount of the component (C) is preferably selected in the range of 0.1 to 2 parts by weight. This amount is 0.1
When the amount is less than 10 parts by weight, the effect is not sufficiently exhibited.
If the amount is more than the weight part, rigidity is reduced, and when a molded product is formed, unfavorable situations such as surface roughening and coloring of the molded product are caused.

As to the components (A) and (D) used in the present invention, acrylic acid esters, methacrylic acid esters, maleic anhydride,
It is also possible to use a copolymerizable vinyl monomer such as acrylic acid, methacrylic acid, p-methylstyrene, pt-butylstyrene, butyl acrylate, acrylonitrile, methacrylonitrile, N-phenylmaleimide and the like. Specific examples of acrylates and methacrylates include ethyl acrylate, propyl acrylate, butyl acrylate, stearyl acrylate, glycidyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, stearyl methacrylate And glycidyl methacrylate.

There are no particular restrictions on the mixing of each component of the present invention, and melt mixing (extruder, Banbury mixer)
For example, a commonly known method can be used. Also, (A)
There is no particular limitation on the method for producing component (D), and bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization,
A generally known method such as suspension polymerization and melt mixing can be used.

Further, if necessary, an antioxidant, a weathering agent, a metal deactivator, an ultraviolet absorber, a light stabilizer, a bleed / blooming agent, a sealability improving agent, a crystal nucleating agent, a flame retardant,
Crosslinking agents, co-crosslinking agents, vulcanizing agents, antibacterial, antifungal agents, dispersants,
Softeners, plasticizers, clay modifiers, coloring inhibitors, foaming agents, foaming aids, coloring agents such as titanium oxide and carbon black,
Metallic powder such as ferrite, inorganic fiber such as glass fiber and metal fiber, organic fiber such as carbon fiber and aramid fiber,
Composite fibers, inorganic whiskers such as potassium titanate whiskers, glass beads, glass balloons, glass flakes, asbestos, mica, calcium carbonate, talc, silica, calcium silicate, hydrotalcite, kaolin, diatomaceous earth, graphite, pumice stone, evo Fillers such as powder, cotton flocks, cork powder, barium sulfate, fluororesins, polymer beads, or mixtures thereof, or other rubbery polymers such as SBR, NBR, B
R, NR, IR, 1.2-polybutadiene, AR, C
R, IIR, and, if necessary, a thermoplastic resin other than the above components, for example, a diene resin, a polyvinyl chloride resin, a polycarbonate resin, a polyacetal resin,
A polyamide resin, a polyester resin, a polyether resin, polysulfone, polyphenylene sulphite and the like can be appropriately compounded.

The housing according to the present invention refers to housings for electric and OA equipment such as televisions, personal computers, printers, copiers, air purifiers, telephones, faxes, personal computers, cellular phones, etc. Also refers to cases such as IC cards. The covers and cases according to the present invention refer to switches, box-shaped containers, top plates of office furniture, front panels, covers of lighting fixtures, and the like. The tray of the present invention refers to trays for ICs, connectors, and the like.

Preferred embodiments of the thermoplastic resin composition of the present invention are as follows. A transparent and persistent antistatic resin using a mixture of PMMA and ABS as a matrix resin.
A transparent and persistent antistatic resin using a mixture of PMMA, ABS and a modified resin as a matrix resin. MBS or MAB
A transparent persistent antistatic resin using S as a matrix resin.
From the resin composition of the present invention, a desired molded product can be obtained by a generally known method such as press molding, injection molding or extrusion molding.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention will be described in more detail with reference to examples unless the gist of the invention is exceeded. Is not limited in any way by these examples. In addition, the present invention relates to the examples,
Are by weight unless otherwise specified. In addition, each physical property of the thermoplastic resin composition was calculated | required according to the method shown below.

(1) Izod impact strength: ASTM D
Measurement was performed at 23 ° C. and 50% RH using a notched 入 っ inch thick test piece according to 256. If the Izod is 80 J / m or less, it is liable to break due to dropping of the package. (2) Surface resistivity: Using a flat plate having a thickness of 1/8 inch, using a pole insulation type SM-10E manufactured by Toa Denpa Kogyo KK
After molding, the condition was measured for 24 hours under the conditions of 23 ° C. and 50% RH, and the measurement was performed.

(3) Total light transmittance: The total light transmittance was measured using a flat plate having a size of 5 cm × 9 cm and a thickness of 2.5 mm. The haze meter of Suga Test Instruments Co., Ltd. (S
M-3). * The value at the time of water absorption is as follows.
The measurement was carried out after standing at 90% for 7 days and then at 23 ° C. and 50% RH for 1 hour. Reduction rate (%) of total light transmittance = (total light transmittance before test−total light transmittance after test) / transmittance before test × 100

(4) -1 Water absorption of elastomer (JI
S-K7209): A molded product having a thickness of 1 mm
After drying for a period of time, the weight change after standing in pure water at 23 ° C. for 2 days was measured. (4) -2 Water absorption at the time of water absorption test: The weight of the test piece of the total light transmittance was measured. Water absorption (%) = (weight after test−weight before test) / weight before test × 100 (5) Refractive index: according to JIS K7142 5.1 A method
The film was measured with an Abbe refractometer. (23
° C, 50% RH)

(6) Production Example of Type C 500 equipped with a stirrer, a nitrogen inlet and a distillation tube
97 g of caprolactam in a ml separable flask,
90 g of polyoxyethylene glycol having a number average molecular weight of 1470, 16.4 g of trimellitic acid, and 4.52 g of diphenylmethane diisocyanate were added to N, N-hexamethylene-bis (3,5-di-t-butyl-4-hydroxycinnamic acid amide). ) (Product name "Irganox" 1098:
Antioxidant) Charge with 0.3g, 50ml of nitrogen
After melting at 150 ° C. while flowing at
Polymerization was performed at 0 ° C. for 4 hours.

1 hour, 2 hours, 4 hours after 260 ° C
0.7, 0.5, 0.3 weight of water during reaction after time
%Met. Next, after adding 0.3 g of tetrabutyl orthotitanate, the pressure was gradually reduced to 1 Torr, and unreacted caprolactam was distilled out of the system. Further, polymerization was carried out at the same temperature under a pressure of 1 Torr or less for 2 hours to obtain a single yellow transparent elastomer (Type C) (Haze 46).
%). This elastomer contains 49% by weight of a polyoxyethylene glycol segment and has a relative viscosity of 1.93.
The melting point was 190 ° C., the crystallization temperature was 121 ° C., and the decomposition temperature was 330 ° C. Table 2 shows the type of antistatic agent.
The physical properties of A, B, and C are shown.

[0030]

Example 1 According to the composition shown in Table 1, they were mixed by a tumbler and melt-mixed at 260 ° C. by a 40 mmφ extruder to obtain desired pellets. The pellets were injection-molded with a 7 oz molding machine to obtain predetermined test pieces, and physical properties were measured. Table 1 shows the results. The contents of the used antistatic agent are shown in Table 2.

[0031]

Examples 2 and 3 Example 1 was repeated except that the formulation was changed to Table 1.
Table 2 shows the results obtained in a similar manner.

[0032]

Comparative Examples 1 to 3 Table 1 shows the results obtained using the formulations shown in Table 1.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

The resin composition of the present invention is excellent in impact strength, has a small decrease in total light transmittance before and after water absorption, has a low surface resistivity, and is a sufficient material as a member for an in-room game machine. .

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 5/51 C08L 25/02 C08L 25/02 33/12 33/12 33/18 33/18 51/04 51/04 55/02 55/02 77/12 77/12 B65D 1/00 A F term (reference) 3E033 AA09 BA11 BA23 BA24 BB01 CA03 CA17 CA18 4F071 AA22 AA33 AA34 AA57 AA77 AC09 AC14 AC15 AF38 AH12 AH19 BC07 4J002 BC06Y BC07W BG04WBG BG04WBG BG10Y BN03X BN12X BN14X BN15X BN16X CL08Z EG016 EV256 EW046 EW066 FD106

Claims (5)

[Claims] 1. A graft copolymer comprising (a-1) 30 to 70 parts by weight of an acrylic resin and (a-2) a rubbery polymer grafted with vinyl cyanide and aromatic vinyl. A transparent matrix resin 70 containing 5 to 40 parts by weight of a rubbery polymer obtained by mixing 30 to 70 parts by weight and (a-3) 0 to 30 parts by weight of a copolymer of vinyl cyanide and aromatic vinyl A thermoplastic elastomer 5 having a refractive index of 1.51 to 1.54, a saturated water absorption at 23 ° C. of 100% by weight or less, and a surface resistivity of 1 × 10 ¹¹ Ω or less; To 30 parts by weight (provided that the difference in refractive index between the transparent matrix resin containing the rubbery polymer as the component (A) and the thermoplastic elastomer as the component (B) is 0.02 or less),
And the component (C) is at least 0 to 10 parts by weight of at least one selected from an organic electrolyte and an inorganic electrolyte, has a surface resistivity of 5 × 10 ¹³ Ω or less, and has little change in total light transmittance when absorbing water. Thermoplastic resin composition. 2. The component (D) in place of the component (A) according to claim 1, comprising (d-1) 0 to 70 parts by weight of a copolymer of methyl methacrylate and aromatic vinyl, and (d-2) A transparent matrix resin 70 containing 5 to 40 parts by weight of a rubbery polymer, 30 to 100 parts by weight of a graft copolymer obtained by grafting methyl methacrylate and aromatic vinyl onto a rubbery polymer
A transparent thermoplastic resin composition characterized by using up to 95 parts by weight. 3. A rubbery polymer obtained by mixing the component (A) according to claim 1 or 2 with 0 to 30 parts by weight of an (a-4) acid-modified or epoxy-modified resin. 4
70 to 95 parts by weight of a transparent matrix resin containing 0 parts by weight,
A transparent thermoplastic resin composition, characterized in that: 4. A housing characterized by using a member molded using the thermoplastic resin composition according to claim 1. 5. A cover and a case using a member molded using the thermoplastic resin composition according to claim 1. Description: