JPS63221148A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having surface dullness which can give an elegant visual sensation and is excellent in strengths and moldability, by mixing an acrylonitrile/styrene resin with a specified crosslinked rubber component. CONSTITUTION:A thermoplastic resin composition comprising 70-95wt.% acrylonitrile/styrene resin (A) (e.g., AS resin or ABS resin) and 5-25wt.% rubber component (B) containing at least 10wt.% unsaturated nitrile/conjugated diene polymer rubber (preferably, a copolymer rubber of 10-50wt.% unsaturated nitrile such as acrylonitrile and 90-50wt.% conjugated diene such as 1,3-butadiene) and crosslinked with a crosslinking agent (a crosslinking agent usually used in the rubber industry, such as a sulfur vulcanizer system or an organic peroxide vulcanizer system). Because this composition has surface dullness of a low gloss value, it requires no embossed mold, is improved in mechanical properties which are problems of a conventional matted molding material and is useful for housings of OA machines and household appliances and automobile interior trims, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an acrylonitrile-styrene thermoplastic resin composition having excellent matte properties.

(Prior art and problems to be solved by the invention)AS
Acrylonitrile-styrene resins such as resins or ABS resins have excellent moldability and mechanical properties, and are therefore used in large quantities as housings for office automation equipment, home appliances, interior materials for automobiles, and the like. These molded objects are sometimes required to have a matte appearance in order to match the color tone with other devices and to provide an elegant visual impression. Conventionally, in order to meet such requirements, addition of inorganic fillers, rubber blends, blends of partially crosslinked polyvinyl chloride (Japanese Patent Laid-Open No. 61
-126173), etc. have been attempted.

Inorganic fillers reduce impact resistance and processability, rubber blends have a low matting effect, and partially crosslinked polyvinyl chloride blends tend to have uneven matting, etc. - there are advantages and disadvantages.

In view of the above problems, the present inventors conducted extensive research to develop a thermoplastic resin composition that provides an elegant visual appearance and has excellent strength properties and moldability. It was discovered that the matting properties of thermoplastic resins made of vulcanized rubber are significantly improved, and the present invention was completed.

(Means for Solving the Problems) Thus, according to the present invention, the rubber composition contains (1) 70 to 95% by weight of an acrylonitrile-styrene resin and (2) at least 10% by weight of an unsaturated nitrile-conjugated diene polymer rubber. Provided is a thermoplastic resin composition with improved matting properties, characterized in that the rubber component is crosslinked with a crosslinking agent in a resin composition comprising 5 to 30% by weight of a rubber component.

The acrylonitrile-styrene resin used in the present invention is a copolymer resin of acrylonitrile and styrene/or α-methylstyrene, which is usually called As resin, AB
An impact-resistant resin in which As resin is grafted onto dispersed polybutadiene rubber particles called S resin [for example, Polymer Science Society of Japan, Polymer Data Handbook Applied Edition, ABS resin,
39-44 (Published by Baifukan on January 30, 1985)], a weather-resistant and impact-resistant polymeric resin called AAS or ASA resin, which is made of acrylic rubber partially grafted with acrylonitrile-styrene copolymer. , EP called ABS resin
A weather-resistant/impact-resistant resin in which acrylonitrile-styrene copolymer is partially grafted to DM rubber is included, and these are used alone or in a mixture of 2 ai or more.

An unsaturated nitrile-conjugated diene polymer rubber or a mixed rubber of this and another rubber is added as a rubber component to the acrylonitrile-styrene resin described above.

The unsaturated nitrile-conjugated diene polymer rubber used in the present invention is preferably a copolymer rubber containing 10-50% by weight of unsaturated nitrile and 90-50% by weight of conjugated diene. Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile; examples of conjugated dienes include 1,3-butanoene,
2,3-dimethylbutadiene, isogren, 1.3--
'? Examples include ntadiene and the like.

There is no problem in replacing a part of the conjugated diene with another copolymerizable monomer as long as the gist of the present invention is not impaired. Such monomers include aromatic vinyl monomers such as styrene and α-methylstyrene, alkyl acrylates such as methyl acrylate, ethyl acrylate), phthyl acrylate, and 2-ethyl acrylate; Alkoxyalkyl acrylates such as methoxy mesol acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, and methquine ethoxyethyl acrylate; unsaturated carganic acids or their alkalis such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid; Salts such as metal salts and ammonium salts, cyanogen-substituted alkyl esters of (meth)acrylic acid such as cyanomethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, and 4-cyanobutyl (meth)acrylate. Monomers other than those exemplified above can also be used as long as they are copolymerizable with unsaturated nitriles and conjugated dienes. Specific examples of unsaturated nitrile-conjugated diene polymer rubbers include acrylonitrile-butadiene copolymer rubber, acrylonitrile-isobray copolymer rubber, and acrylonitrile-isobrae copolymer rubber.
Examples include acrylonitrile-butadiene-isoprene copolymer rubber, acrylonitrile-butadiene-acrylic acid copolymer rubber, and rubbers in which the conjugated diene units in these rubbers are hydrogenated.

Other rubbers that can be used in combination with the unsaturated nitrile-conjugated diene polymer rubber used in the present invention can be crosslinked with crosslinking agents commonly used in the rubber industry, such as sulfur vulcanization and organic peroxide vulcanization. Any rubber may be used, such as polybutadiene rubber, styrene-butadiene copolymer rubber (random, block), natural rubber, conjugated tsene-based polymer rubber such as polyisoprene rubber, polychloroprene rubber, and its hydride, EPD
Examples include M. For mixing the unsaturated nitrile-conjugated diene polymer rubber with the other rubbers mentioned above, the proportion of the unsaturated nitrile-conjugated diene polymer rubber in the mixed rubber should be at least 10% by weight, 10% by weight. If the amount is less than % by weight, the matting properties will not be improved.

Preferably it is 20 folds or more.

The thermoplastic resin composition of the present invention is obtained by mixing the acrylonitrile-styrene resin described above and a rubber component. When a mixed rubber is used as a rubber component, two or more rubbers may be mixed in advance and then mixed with the resin, or they may be added to the resin simultaneously or separately. The content of the rubber component in the resin composition is 5 to 3
If the amount is less than 5% by weight, the matting properties will be insufficient, and if it exceeds 30% by weight, the hardness of the molded product will be low.

Preferably it is in the range of 7 to 25% by weight.

Furthermore, it is necessary that the rubber component be crosslinked with a crosslinking agent in the resin composition of the present invention.

In the present invention, there is no particular restriction on the method of crosslinking the rubber component, but in the process of mixing the resin and the rubber component, so-called dynamic vulcanization is performed in which the rubber component is crosslinked at the same time as mixing in the presence of a crosslinking agent for the rubber component. This method is particularly suitable.

When dynamic vulcanization is used, the resin and the rubber component are sufficiently melted and mixed in advance, and then a crosslinking agent for the rubber component is added, and the temperature and temperature necessary for the resin to melt and the rubber component to be vulcanized is maintained. Continue time mixing. Since the mixing temperature and time for vulcanizing the rubber components vary depending on the type of rubber component and the type of crosslinking agent, it is necessary to determine the vulcanization conditions through preliminary experiments. The temperature is usually 150 to 230°C for 5 to 10 minutes.

When using ABS, etc. containing dispersed rubber particles as the acrylonitrile-styrene resin, the dispersed rubber particles may cause thermal deterioration at the temperature of dynamic vulcanization of the rubber component. A mixture of the resin and the rubber component is prepared by crosslinking the rubber component by a dynamic vulcanization method, and this is mixed with ABS, etc. to form a predetermined thermoplastic resin composition. A preferred manufacturing method is a method of producing a product. In order to fully achieve the purpose of the present invention, it is essential that the rubber component is crosslinked, but the glue content (insoluble when the crosslinked rubber component is immersed in methyl ethyl ketone for 48 hours at 25°C) is It is desirable that the crosslinking be carried out so that it becomes 80 inches or more. Further, it is preferable that the rubber component is dispersed in the resin composition in the form of particles of 10 μm or less, more preferably 1 to 5 μm, from the viewpoint of matting properties and impact resistance.

The vulcanizing agent used in the present invention is not particularly limited as long as it vulcanizes the rubber component. Typically, sulfur and/or sulfur-donating compounds (e.g. thiuram compounds such as tetramethylthiclam disulfide, tetraethylthiuram disulfide, morpholin compounds such as morpholin disulfide) and zinc oxide, magnesium oxide, zinc stearate, etc. Vulcanization aids such as stearic acid, vulcanization accelerators, such as guanidine compounds such as nophenylguanidine, thiazole compounds such as mercaptobenzothiazole, benzothiazyl disulfide, cyclohexylbenzothiazyl sul-7enamide, tetra Sulfur vulcanization system using thiuram compounds such as methylthiuram monosulfide and tetramethylthiuram disulfide, dicumyl peroxide, 2,5-
Dimethyl-2,5-no(t-pterno9-oxy)-
Hexane, 2,5-tmethyl-2,5-no(t-butylnozaroxy)-hexyne-3,1,3-bis(1-
Organic peroxide vulcanization systems such as butylene/l/peroxy-isopropyl) benzene and the like are used. The amount of these vulcanization systems used is such that the amount of the rubber component becomes the amount described above.

Various compounding agents such as fillers, colorants, plasticizers, lubricants, and stabilizers are usually added to the resin composition of the present invention as appropriate depending on the required performance. ,
Alternatively, it may be added after vulcanization of the rubber component, and the timing of addition of the compounding agent is not particularly limited.

(Effects of the Invention) The thus obtained thermoplastic resin composition of the present invention is elegant and has a matte property with a low gloss value, so it does not require the use of a textured mold and also solves the problems of conventional matte molding materials. Since the deterioration of mechanical properties, which is a point, has been improved, it is useful as housings for office automation equipment, home appliances, etc., automobile interior materials, etc.

(Example) The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these examples. In the Examples and Comparative Examples, the number of parts used is based on weight, unless otherwise noted.

Examples 1 to 15, Comparative Examples 1 to 4 First, As resin (Sunrex 5AN-C manufactured by Mitsubishi Monsanto Chemical Co., Ltd.) and the rubber components listed in Tables 1 and 2 were mixed into 1
Mixing was performed using a roll at 60°C. After mixing until good rotation puncture is obtained, add the crosslinking agent listed in each table,
The mixture was mixed again until good rotation puncture was obtained, dynamic vulcanization was performed, and sheeting was performed (7 minutes from addition of the vulcanizing agent to sheeting). The resulting AS resin/rubber component mixture and Ag5llti (Diapet 3 manufactured by Mitsubishi Rayon Co., Ltd.)
001) were mixed using a roll at 170°C in the proportions listed in each table. After mixing until a good rotational puncture is obtained and taking out a sheet, the pellet forming machine is used to i)-! A pelletized thermoplastic resin composition was obtained. These pellets were molded using a 40 mm diameter injection molding machine, with a head temperature of 220°C, a screw rotation speed of 6 Orpm, and an injection pressure of 50 kg/cTn.
”, molded at a gauge injection speed of 50 cm, length 9 cm
A 1110 plate of rlL×width 5crIL×thickness 2 was obtained.

Impact resistance conforms to DIN53453, gloss level conforms to JIS
Measured according to Z8741. The impact resistance is inferior to that of ABS resin that does not contain vulcanized rubber components] ×, 5
An improvement of less than 1 inch is indicated by Δ, an improvement of 5% to less than 10% is indicated by ○, and a case of an improvement of 10 channels or more is indicated by ◎. Glossiness is the average value of the results measured at five different positions on one plate.

The evaluation was made by taking into account the visual sensation. Similar to the impact resistance evaluation, when compared to ABS resin that does not contain a vulcanized rubber component, a cross value of 80 inches or more is ×, less than 80% to 65% or more is △,
Less than 65 inches to 50 inches or more were marked ◎. rubber component r
To measure the Ti content, a certain amount of small pieces of the As resin/vulcanized rubber component mixture were immersed in methyl ethyl ketone at 25° C. for 48 hours, and the insoluble fraction was determined as a percentage of the Ti content in the rubber component in the mixture. The above results are shown in Tables 1 and 2.

Note) αQ Diapet 3001α1 manufactured by Mitsubishi Rayon Co., Ltd. Dibenzothiazyl di-y' ruphide θ→ Diphenylguaninone

Claims (2)

[Claims] (1) Acrylonitrile-styrene resin 70-95% by weight (2) A resin composition comprising 5 to 25% by weight of a rubber component containing at least 10% by weight of unsaturated nitrile-conjugated diene polymer rubber, characterized in that the rubber component is crosslinked with a crosslinking agent. A thermoplastic resin composition with improved matte properties.