JPS60158242A - Resin composition - Google Patents

Abstract

PURPOSE:A methyl methacrylate/styrene resin composition having an excellent antistatic effect and a good balance between mechanical and thermal properties, prepared by mixing a higher fatty acid monoglyceride with a specified sec. amine. CONSTITUTION:Use is made of a sec. amine of the formula (wherein R1 is an aliphatic, alicyclic or aromatic hydrocarbon group, and R2 is a 1-8C alkylene group), e.g., Dasper 125B(a product of Miyoshi Yushi Ltd.). Namely, 100pts.wt. methyl methacrylate/styrene resin is melt-blended with 1-4pts.wt. higher fatty acid monoglyceride (e.g., stearic acid monoglyceride) and 1-3pts.wt. above sec. amine by means of an extruder or the like.

Description

[Detailed description of the invention] This invention relates to an acid methyl-styrene resin composition.

Methyl methacrylate-styrene thread resin (hereinafter referred to as MS resin) is used for audio equipment nameplates, office equipment nameplates, lighting equipment, etc. because of its transparency, gloss when colored, and beautiful appearance1. However, since its surface resistivity is extremely high, it tends to be easily charged, and its appearance is often damaged due to the adhesion of dirt and dust due to the charging.

Conventionally, as a method for preventing static electricity on synthetic resins, additives such as surfactants are added and kneaded, but in the additive kneading method, additives that have an antistatic effect are added to polystyrene resin. MSI (Even if it is applied to fats, the effect is not sufficient or the transparency is inhibited, so there is no satisfactory result.In addition, if the amount of additives added is increased until the antistatic ability is recognized, the MSS side It cannot be put to practical use because it is accompanied by a decrease in the physical properties of wood, especially heat resistance, thermal stability, and strength.For example, as a surface coating method, Statyside (trade name, An
alyt1calCh@mical Laborato
(manufactured by Ries, Inc.) is effective, but the effect is lost when washed with water after application, and it is not permanent, and there are problems in terms of cost, so it cannot be said to be an excellent method.

In addition, in order to impart antistatic properties to acrylic resin compositions, a method of adding I higher fat fatty acid glyceride, polyalkylene glycol, and phosphorus compound to acrylic resin (%Kasho 5l-49246) and glycerin A method of adding fatty acid ester and sodium alkylsulfonate has been proposed (Japanese Patent Application Laid-open No. 58-125741), but no significant effect is observed when any of these methods is applied to MS resin.

The inventor of the present invention arrived at the present invention as a result of intensive studies to obtain an MS resin with antistatic properties. By adding higher fatty acid monoglyceride and a specific secondary amine together, a small amount of MS resin can be obtained. MS with excellent antistatic effect and good balance of mechanical and thermal properties
They were able to obtain resin.

That is, the present invention provides 1.0 to 460 parts by weight of higher fatty acid monoglyceride and the formula (1
) The present invention relates to a resin composition having excellent antistatic properties, which is characterized by containing 1.0 to 3.0 parts by weight of a secondary amine represented by the following formula.

(However, R1 is an aliphatic, alicyclic or aromatic hydrocarbon group, and R2 is a C1 to C3 alkylene group.) In formula (1), R8 is a C□ to CIl+ linear alkyl group. Secondary amines in which R2 is CH or CH are particularly preferably used.

When higher fatty acid monoglyceride was cooled alone to MS resin, the surface resistivity value of the product hardly decreased even if 10 parts by weight was added to 100 parts by weight of MS resin, and the antistatic effect was not sufficient. .

In addition, when the specific secondary amine shown in formula (1) is used alone, when 10 parts by weight is added to 100 parts by weight of MS resin, the surface resistivity value decreases to 10° ohm, resulting in good antistatic properties. Although it was effective, the heat resistance of the MS resin was significantly lowered and yellowing was severe, making it impossible to put it to practical use. However, when higher fatty acid monoglyceride and the specific secondary amine shown by formula (1) are added in combination, the total amount of addition required can be reduced compared to when they are added alone. It was possible to obtain an antistatic MS resin having favorable physical properties.

Examples of higher fatty acid monoglycerides constituting the composition of the present invention include monoglycerides such as lauric acid, palmitic acid, stearic acid, montanic acid, oleic acid, linoleic acid, and behenic acid. Usually, these contain small amounts of diglyceride and triglyceride, but those with high purity of 90% or more of monoglyceride are preferable.

If the purity is low, even a small amount of addition may inhibit the transparency of the MS resin. The amount of higher fatty acid monoglyceride added is 1.0 to 4.0 parts by weight per 100 parts by weight of the MS resin. If the amount is less than 1.0 parts by weight, the antistatic effect will be poor, and if it is used in excess of 4.0 parts by weight, the physical properties of the MS resin, especially the heat resistance, will be significantly reduced, and furthermore, it will become cloudy and its transparency will be significantly reduced. Something may go wrong.

The amount of the secondary amine represented by formula (1) constituting the composition of the present invention is M S it (1 part by weight per 100 parts by weight of fat).
．． It is 0 to 3.0 parts by weight. If the amount is less than 1.0 parts by weight, the antistatic effect will be poor, and if it is used in excess of 3.0 parts by weight, the physical properties of the MS resin, especially the heat resistance, will be significantly reduced, and yellowing will be severe enough to make it impossible to use it as a product. I can't stand it anymore.

In the present invention, M S g (fat) refers to a copolymer containing 20% by weight or more of methyl methacrylate and 20% by weight or more of styrene, the total of which is 50% by weight or more, 20% by weight or more of methyl methacrylate. and a styrene derivative, for example, a copolymer containing 20% by weight or more of α-substituted styrene such as α-methylstyrene, or nuclear-substituted styrene such as p-methylstyrene, and the total of both is 50% by weight or more, and A copolymer made by copolymerizing the above monomer composition as an essential component with one or more copolymerizable monomers such as acrylic ester, methacrylic ester, acrylonitrile, etc., and mixing or grafting of synthetic rubber to these copolymers. It means a polymer contained in the form of a chemical bond such as
It can be obtained by commonly known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk-suspension polymerization.

The composition of the present invention can be obtained by melt-kneading M S $1 fat, higher fatty acid monoglyceride, and a secondary amine represented by formula (1) in an extruder or the like. Also,
The formula (1
) can also be obtained by melt-kneading a secondary amine represented by () using an extruder or the like.

Molded products obtained by molding the MS resin composition of the present invention obtained in this manner by a molding method such as injection molding or extrusion molding have a small surface resistivity value, a short charge decay half-life, and have excellent properties. Shows antistatic properties. Examples of molded products include nameplates for home appliances, meter covers, IC-related cases, covers and cases for office automation equipment.

Additives commonly used in the compositions of the invention, such as plasticizers, stabilizers, colorants, etc., may be added.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Examples 1 to 9, Comparative Examples 1 to 5 100 MS resin beads with a weight average molecular weight of 150,000, consisting of 501f% methyl methacrylate and 50% styrene
Stearic acid monoglyceride (trade name Rigmar 5100A, manufactured by Riken Vitamin Co., Ltd.) and formula (1) are added to the weight part.
Secondary amine represented by (Formula (1), R6 is CH,
CH, and R1 is a mixture of an alkyl group of C1t and an alkyl group of C14.

Product name Das/”-125Be (manufactured by Myoshi Yushi Co., Ltd.) is shown in Table 1.
They were added at various ratios shown in , and melt-kneaded at 200°C using a 40ytanφ extruder to form pellets. The obtained pellets were molded using a 2-ounce injection molding machine at a cylinder temperature of 230℃ and a mold temperature of 40℃ for 40 m,
A 40 rtrrr, X 2 van flat plate was obtained by injection molding.

The antistatic performance of the obtained flat plate was measured. The results are summarized in Table-1.

From Table 1, it can be seen that the resin composition according to the present invention has good antistatic performance and has an appearance that is sufficiently useful as a commercial product.

Example 10 57.5 parts by weight of methyl methacrylate and 42 parts by weight of styrene.
100 parts by weight of MS resin produced by graft polymerizing 5 parts by weight of styrene-butadiene rubber whose refractive index matches that of this monomer mixture to a monomer mixture consisting of 5 parts by weight,
Stearic acid monoglyceride (part name Rikemar S1
0. OA, manufactured by Riken Vitamin Co., Ltd.) and 3 parts by weight of formula (1
) (in formula (1), R2 is CH
, CH, and R1 is a mixture of an alkyl group of CO and an alkyl group of CI4. Product name: Mesper 1
25B (manufactured by Miyoshi Oil Co., Ltd.) was added in an amount of 2N, and the temperature was 40 mmφ.
The mixture was melt-kneaded at 200°C using an extruder to form pellets. The resulting pellets were molded using a 2 oz injection molding machine.
Cylinder temperature 230℃.

40 mm x 40 mn x at mold temperature 40℃
A 2 wn flat plate was obtained by injection molding. The surface resistivity value of the obtained flat plate was 8×10ζ], and the charge decay half-life was 3 seconds. Moreover, the flat plate was pale yellow and completely transparent.

Comparative Example 6 In Example 10, when stearic acid monoglyceride and the secondary amine represented by the formula il+ were not added to the MS resin, the surface specific resistance value was I x 1016Ω, and the charge decay half-life was infinite.

Special liver applicant: Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] Methyl methacrylate - 1.0 to 4.0 parts by weight of higher fatty acid monoglyceride and 1.0 to 3.0 parts of secondary amine represented by formula (1) per 100 parts by weight of styrene resin. A resin composition characterized in that it contains a heavy weight. (However, R8 is an aliphatic, alicyclic, or aromatic hydrocarbon group, and R2 is a C8 to C8 alkylene group.)