KR20000055391A - styrenic thermoplastic resin compositions with good release property at sheet extrusion die - Google Patents

Abstract

PURPOSE: A styrene type thermoplastic resin composition which has excellent sheet extrusion die releasability, thereby improving work efficiency is provided by introducing fatty acids having an average diameter of 100 micrometer or less as a lubricant to ABS resin. CONSTITUTION: A styrene type thermoplastic resin composition which has excellent sheet extrusion die releasability is characteristically comprised of (A) graft copolymer resin of 25-40 wt.% containing styrene with rubber particles having average diameter of 0.28-0.40 micrometer, (B) base resin hundred parts by weight comprised of 60-70 wt.% of copolymer resin containing styrene, and (C) fatty acids having average diameter of 100 micrometer or less as a lubricant of 0.4-1.0 parts by weight. The graft copolymer resin containing styrene(A) has a grafting degree of 50-70 wt.% and a weight average molecular weight of 50000-60000, and the copolymer resin(B) has a weight average molecular weight of 120000-60000.

Description

Styrenic thermoplastic resin compositions with good release property at sheet extrusion die}

Field of invention

The present invention relates to a thermoplastic resin composition having excellent sheet extrusion die releasability. More specifically, the present invention relates to a method for producing a resin composition having excellent releasability in T-Die during sheet extrusion in preparing a composition of acrylonitrile-butadiene-styrene copolymer resin (ABS resin).

Background of the Invention

In general, ABS resins have excellent mechanical properties and are widely used in electrical and electronic parts, office equipment, automobile parts, and the like. Most of these molded products are produced by injection molding, but in the case of large molded articles or curved surfaces on the outside of the molded articles, they are manufactured by vacuum molding or blow molding. Vacuum molding is a sheet extruded resin to prepare a sheet sheet, and then the sheet is heat-softened in a vacuum molding machine and subjected to vacuum or pressure and vacuum at the same time to bring the softened sheet into close contact with a mold to obtain a product of a desired shape. It is a kind of plastic molding method.

In the sheet extrusion as described above, it is usually processed into a sheet form rather than a strand form through T-Die. At this time, if the die release of ABS resin becomes bad, it is difficult to remove the resin during disassembly and maintenance, and scratches are generated on the surface of the processed sheet due to the resins attached to the die. Let's do it. Therefore, a resin having excellent die releasability is required to smooth the surface of the sheet and to improve workability during disassembly and maintenance.

The inventors mixed ethylene bis stearamide (EBS: ethylene bis stearamide) as a lubricant in ABS resin to solve the above problems, but less than 100㎛ less than 200 mesh (bead) in the form of bead (bead) Application of fine particles has led to the development of thermoplastic resin compositions with significantly improved sheet extrusion die release properties.

An object of the present invention is to provide a thermoplastic resin composition excellent in sheet extrusion die releasability by applying EBS in the form of very fine particles filtered with 200 mesh to the ABS resin.

Another object of the present invention is to provide a thermoplastic resin composition having a smooth sheet surface and excellent die release property with improved workability during decomposition and maintenance.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The resin composition of this invention consists of 25-40 weight% of styrene containing graft copolymer resins which are 0.28-0.40 micrometers in average size of (A) rubber particle, and (B) 60-75 weight% of styrene containing copolymer resin. It is made by adding 0.4-1.0 weight part of fatty acid type lubricants with an average size of 100 micrometers or less with respect to 100 weight part.

(A) Styrene-containing graft copolymer resin

The styrene-containing graft copolymer is 90-50% by weight of one aromatic vinyl monomer such as styrene and acrylonitrile in the presence of 20-70% by weight of butadiene-based rubber having a size of 0.28-0.40 µm or more of rubber particles. Graft ratio obtained by graft copolymerization as a graft copolymer emulsion-polymerized or bulk-polymerized by a conventional polymerization method by adding 80 to 30% by weight of a mixture of monomers composed of 10 to 50% by weight of an unsaturated nitrile monomer such as This is 50 to 70%, and the weight average molecular weight of the grafted resin is 50,000 to 60,000.

(B) styrene-containing copolymer resin

The styrene-containing copolymer resin (B) is represented by a vinyl cyanide compound-aromatic vinyl compound copolymer, and is a copolymer polymerized in a conventional manner using 10 to 50 parts by weight of a vinyl cyanide compound and 90 to 50 parts by weight of an aromatic vinyl compound. .

Acrylonitrile or methacrylonitrile may be used as the vinyl cyanide compound, and styrene, α-methylstyrene, or a mixture thereof may be applied as the aromatic compound. A monomer such as methacrylic acid ester compound such as methyl methacrylate and butyl acrylate, N-phenylmaleimide, N-cyclohexyl maleimide, maleic anhydride and the like can be added and copolymerized.

In addition, by adding a compound capable of suppressing changes in crosslinking, agglomeration, or the like during the production of the resin, poor appearance and extrusion instability of the molded article generated during resin processing or extrusion can be solved. The average molecular weight of the said copolymer resin is 120,000-600,000.

(C) fatty acid lubricants having an average particle size of 100 μm or less

Fatty acid type lubricant (C) is added to the ABS resin composition to improve die release properties of the resin during sheet extrusion. The fatty acid lubricant (C) is added in an amount of 0.4 to 1.0% by weight based on 100% by weight of the ABS resin composition, and it is preferable to use ethylene bis stearamide (EBS). It is preferable to apply the EBS to very fine particles having an average particle diameter of 100 μm or less that is filtered through 200 meshes, not a general bead form, and more preferably, an average particle diameter of EBS is 70 μm or less.

The resin composition according to the present invention may be prepared by adding additives such as heat stabilizers, lubricants, and the like, which are commonly used.

The present invention can be further embodied by the following examples which are intended to illustrate the invention, and are not intended to limit the scope of the invention.

Example

(1) Preparation of Graft Copolymer (g-ABS)

45 parts by weight of polybutadiene latex (average particle size 0.32 µm) and 200 parts by weight of deionized water were added to a polymerization reactor equipped with a stirring device, a reflux cooler, a thermometer, and a preparation device. 60 parts by weight of styrene and 40 parts by weight of acrylonitrile were added to the part and the monomer mixture, and 0.1 parts by weight of t-dodecylmercaptan was continuously added for 3 hours to polymerize at 70 ° C. The latex obtained here was dropped into 4% aqueous sulfuric acid solution heated to 90 ° C., and then washed and dehydrated to obtain a graft copolymer. The graft ratio of the copolymer obtained here was 50% and the weight average molecular weight of the grafted acrylonitrile-styrene copolymer was 50,000.

(2) Preparation of Copolymer (SAN-1)

Stainless steel high pressure reactor equipped with a stirrer 71% styrene, 29% acrylonitrile, 150 parts of ion-exchanged water, 0.4 parts of the third calcium, 0.03 parts of carboxylic acid anionic surfactant, 0.01 parts of polyoxyethylene alkyl ether phosphate ester, 0.5 parts of 2,2'-azobisisobutylonitrile as an initiator and 0.1 parts by weight of t-dodecyl mercaptan were added to the reactor, and the reactor was completely sealed. After sufficiently stirring and dispersing, the temperature of the reactor was increased to 75 The polymerization was carried out for 6 hours at ℃. After the reaction was completed by cooling the inside of the reactor to room temperature, the obtained polymer was washed, dehydrated and dried to obtain a bead copolymer. The weight average molecular weight of the obtained acrylonitrile-styrene copolymer was the range of 220,000-260,000, and the content of acrylonitrile was 23-28 weight%.

(2) Preparation of Copolymer (SAN-2)

Except that 0.3 parts by weight of t-dodecyl mercaptan was applied in the same manner as in the preparation of the copolymer (SAN-1). The weight average molecular weight of the obtained copolymer was in the range of 270,000 to 330,000, and the content of acrylonitrile was 23 to 28% by weight.

Example 1

The graft copolymer and the acrylonitrile-styrene copolymer (S-1) and (S-2) are respectively mixed in a ratio of 30:55:15, and are conventional heat stabilizers and lubricants based on 100 parts by weight of the resin. A mixture of 0.7 parts by weight of EBS was prepared using a twin screw extruder having a diameter of 40 mm to produce pellets (commonly referred to as ABS resin). The EBS used at this time is in the form of beads, with an average particle diameter of 70 μm. The pellets were subjected to sheet extrusion for 72 hours using a sheet extruder having a screw diameter of 40 mm, and then the T-Die and the screw were disassembled to show the results for the release property and the amount of screw scale. 1 is shown.

Example 2

Except that 0.6 parts by weight of EBS having an average particle diameter of 1 mm and 0.1 parts by weight of EBS having an average particle diameter of 70 μm was carried out in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1

Except that the average particle diameter of 1mm or more using EBS was carried out in the same manner as in Example 1 and the results are shown in Table 1.

Example 1 Example 2 Comparative Example 1 T-Die Release ○ △ × Screw Scale amount Less Less plenty

○: When T-Die surface is exposed when T-Die upper / lower board is separated

(The resin runs out)

△: T-Die surface is partially exposed when T-Die upper / lower plate is separated

×: T-Die surface is not exposed when separating T / Die upper / lower board

(Resin stuck to Die)

The present invention has the effect of providing a styrene-based thermoplastic resin composition excellent in sheet extrusion die release property by applying a fine fatty acid-based lubricant having an average particle diameter of 100 µm or less to the ABS resin.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (4)

To 100 parts by weight of the base resin consisting of 25 to 40% by weight of a styrene-containing graft copolymer resin having an average size of (A) rubber particles of 0.28 to 0.40 µm and (B) of 60 to 75% by weight of a styrene-containing copolymer resin, (C) Styrene-based thermoplastic resin composition excellent in sheet extrusion die releasability, comprising 0.4 to 1.0 parts by weight of a fatty acid-based lubricant having a particle average size of 100 µm or less. The styrene-based thermoplastic resin composition according to claim 1, wherein the graft ratio of the styrene-containing graft copolymer (A) is 50 to 70% and the weight average molecular weight is 50,000 to 60,000. The styrene-based thermoplastic resin composition according to claim 1, wherein the average particle size of the fatty acid lubricant is 70 µm or less. The styrene-based thermoplastic resin composition according to claim 1, wherein the fatty acid lubricant is ethylene bis stearamide.