JPH03134045A - Vinyl chloride resin composition and molded article thereof - Google Patents

Abstract

PURPOSE:To prepare the title resin compsn. having excellent thermal stability and thermal flowability and giving a molded article having an excellent flame retardance by compounding a vinyl chloride resin having a specified mean chlorine content with a specific impact modifier and calcium stearate each in a specified amt. CONSTITUTION:40-80 wt.% vinyl chloride resin having a mean chlorine content of 60-70 wt.% is compounded with 5-30 wt.% at least one impact modifier selected from the group consisting of an acrylonitrile-butadiene-styrene resin, a methacrylate-butadiene-styrene resin, a chlorinated polyethylene, and an acrylic rubber and 0-40 wt.% copolymer of a styrenic compd. with a vinyl cyanide compd. (e.g. a styrene-acrylonictile copolymer). Then, 100 pts.wt. resulting compsn. is compounded with 2.5-6 pts.wt. calcium stearate to give the title resin compsn., which is easily injection molded and suitably used for an automotive interior part, a housing of office automation equipment, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vinyl chloride resin composition and a molded article obtained by injection molding the same.

(Prior art) PVC resin has excellent properties such as flame retardancy, chemical resistance, and weather resistance, but because of its low heat resistance, it is used in housings for office automation (hereinafter referred to as OA) equipment and automobiles. It was unsuitable for use on parts exposed to high temperatures, such as the internal parts of a car.

ABS is a method of imparting heat resistance to vinyl chloride resin.
The addition of resin has been actively researched. For example, JP-A-63-191851 discloses a flame-retardant resin made of a vinyl chloride resin made of polyvinyl chloride or a copolymer of a monomer copolymerizable with polyvinyl chloride, and a rubber-modified thermoplastic resin. A resin composition has been proposed, and the rubber-modified thermoplastic resin is a graft copolymer made by copolymerizing a styrene copolymer of a styrene compound and a vinyl cyanide compound, and a conjugated diene rubber, a styrene compound, and a vinyl cyanide compound. It is described that it is made of a polymer.

Although the above composition has improved heat resistance, it has poor thermal fluidity, and when molded using methods such as injection molding, it is necessary to use bisamide lubricants such as ethylene bisstearamide, polyethylene wax, and higher alcohols. , lubricating agents such as stearic acid metal salts are added.

However, the thermal fluidity during injection molding is still insufficient, and a molded product with a perfect shape may not be obtained due to short shots during injection molding, or shear heat generation occurs when the injection speed is increased to obtain silver (silver). However, there were disadvantages in that poor appearance such as discoloration occurred.

(Problems to be Solved by the Invention) In view of the above-mentioned drawbacks, the object of the present invention is to have excellent thermal stability and thermal fluidity, be easily injection molded, and have flame retardant, chemical resistant, heat resistant, etc. An object of the present invention is to provide a vinyl chloride resin composition capable of obtaining a molded article having excellent properties, and a molded article obtained by injection molding the same.

(Means for Solving the Problems) The vinyl chloride resin (a) used in the present invention refers to vinyl chloride resin, vinyl chloride, and ethylenically unsaturated bonds such as ethylene and propylene that can be copolymerized with vinyl chloride. This refers to copolymers with monomers having the following and post-chlorinated products of these resins.

The average degree of polymerization of the vinyl chloride resin (a) is preferably from 300 to 800, because if it becomes small, the impact resistance of the obtained molded product will decrease, and if it becomes large, the thermal fluidity will decrease. Preferably, a vinyl chloride resin having a degree of polymerization of 300 to 800 is post-chlorinated. It is preferable to use a vinyl chloride resin having an average degree of polymerization of 300 to 800 and a chlorinated vinyl chloride resin obtained by post-chlorinating the vinyl chloride resin having an average degree of polymerization of 300 to 800.

The average chlorine content of the vinyl chloride resin (a) is limited to 60 to 70 wt%, because if it is too low, the heat resistance will be lowered, and if it is too high, the thermal fluidity will be low, making injection molding difficult. Therefore, the vinyl chloride resin (a) is used alone or in combination of two or more resins so that the chlorine content falls within this range.

The impact modifier (b) used in the present invention is selected from the group consisting of ABS resins, MBS resins, chlorinated polyethylenes, and acrylic rubber resins, and one or more of them are used in combination.

The above ABS resin is a resin in which styrene, acrylonitrile, methacrylonitrile, etc. is graft-polymerized to a rubber component such as polybutadiene or styrene-butadiene copolymer, and contains 20 to 70 wt% of the rubber component. preferable. Moreover, its molecular weight is 0.5 to 0.0 in terms of specific viscosity.
8 is preferred. In addition, the specific viscosity is 0.4g/100m
A chloroform solution with a concentration of 1 was measured at 25°C.

The above-mentioned MBS resin refers to rubber resins such as polybutadiene and styrene-butadiene copolymers, acrylic monomers such as methyl acrylate, ethyl acrylate, and ethyl methacrylate, acrylonitrile monomers such as acrylonitrile and methacrylonitrile, styrene, α−
A graft polymer obtained by graft polymerizing styrenic monomers such as methylstyrene, with a rubber resin component of 4
It is preferably 0 to 60 wt%, and examples thereof include Kane Ace B-23 manufactured by Shibuchi Kagaku Co., Ltd. and Metaprene C-110 manufactured by Mitsubishi Rayon Co., Ltd.

The above-mentioned chlorinated polyethylene has a chlorinated degree of 30 to 40 W, since the impact improvement effect decreases if the degree of chlorination is too high or low.
t% is preferred. Also, the average molecular weight is 100,000 to 15
Ten thousand is preferable.

The above acrylic rubber resin is mainly composed of acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and octyl acrylate, and is a combination of acrylate and monomers such as 2-chloroethyl vinyl ether, methyl vinyl ketone, acrylic acid, acrylonitrile, and butadiene. It is a polymer, and examples thereof include Kane Ace PM manufactured by Shibuchi Kagaku Co., Ltd., and Kureha KM-334 manufactured by Kureha Chemical Co., Ltd.

The styrenic copolymer (c) used in the present invention is a copolymer of a styrene compound and a vinyl cyanide compound.

Examples of the above styrene compounds include styrene, α
-Methylstyrene, etc., and styrene is preferred because it has excellent thermal fluidity.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile, with acrylaterile being preferred because it has excellent compatibility with vinyl chloride resins.

The styrenic copolymer contains a styrene compound and a vinyl cyanide compound in a ratio of 60% due to its impact resistance and thermal fluidity properties.
It is preferable that they are copolymerized at a ratio of 40 to 80:20 (weight ratio), and the weight average molecular weight should be 30,000 to 30,000, since the smaller the weight average molecular weight, the lower the impact resistance of the molded product, and the larger it is, the lower the thermal fluidity. ~100,000 is preferred, and acrylonitrile-styrene resin is preferably used.

The resin composition of the present invention is composed of the vinyl chloride resin (a), the impact modifier (b), and the styrene copolymer (c). If the amount of the impact modifier (b) added decreases, the impact resistance decreases, and if it increases, the thermal fluidity and heat resistance decrease, and if the amount of the styrenic copolymer (c) added decreases, the impact resistance decreases. If this happens, the impact resistance will decrease, so if the vinyl chloride resin (a)
0~80wt% added, impact modifier 佽) is added 5~30w
t% added, styrenic copolymer (c) is 0 to 40w
t% is added.

The vinyl chloride resin composition of the present invention is the above-mentioned resin composition 10.
0 parts by weight and 2.5 to 6 parts by weight of calcium stearate. Conventionally, the amount of calcium stearate added was 2 parts by weight or less, but such a small amount caused discoloration during injection molding and caused poor appearance.

When the amount of calcium stearate added is 2.5 parts by weight or more, thermal stability, especially stability when heated for a long time, is improved, no burning occurs during injection molding, and the appearance of the molded product is good. The range of injection conditions under which good molded products can be obtained becomes wider. If the amount exceeds 6 parts by weight, it tends to bleed from the surface, resulting in decreased weather resistance, whitening, and decreased impact resistance.

The composition of the vinyl chloride resin composition of the present invention is as described above, and further includes polyethylene wax, higher alcohol, and ester, which are commonly used to improve moldability, thermal stability, etc. of vinyl chloride resin. lubricants such as polymethyl methacrylate processing aids, diptyltin malate, dibutyltin mercapto, metal soaps, heat stabilizers such as lead compounds, antioxidants, ultraviolet absorbers, lubricants, calcium carbonate, glass fibers. fillers such as, pigments such as titanium oxide, dyes, etc. may be used in combination.

The vinyl chloride resin composition of the present invention can be molded by any conventionally known heating method such as extrusion molding, calendar molding, roll press molding, injection molding, etc., but is suitable for injection molding. The second invention of the present invention is a molded article obtained by injection molding the vinyl chloride resin composition.

In order to injection mold the above vinyl chloride resin composition, for example, the composition may be uniformly dispersed using a super mixer, or this mixture may be fed to an extruder and pellets obtained by cutting the composition using a Berekizer may be fed into an injection molding machine. The injection condition is generally a barrel temperature of 170 to 190'.
C1 injection pressure is 120 to 150 Kg/cd.

(Example) Next, the present invention will be explained in detail. Note that "parts" hereinafter mean "parts by weight". In addition, the method for measuring physical properties is as follows.

1.Create a sample with thermal deformation degree of -2' x 12 x 90m+, fix one end, apply a load of 2g, and heat at 85°C
After standing for a period of time, the deflection distance (L) was measured and calculated from the following equation.

Thermal deformation degree (%) = (L/90)X1002, impact strength (notched isot strength) - ASTM D-256
0.125 inch thick samples were measured at 23°C.

Examples 1 to 3, Comparative Example 1.2 A total of 100 parts of the predetermined amounts of vinyl chloride resin, impact modifier, and styrene copolymer shown in Table 1, calcium stearate, and diptyltin malate 3.0 parts. and 0.5 parts of dibutyltin mercapto to a super mixer;
After mixing well, pelletization was performed using a twin-screw extruder with a screw diameter of 45 mm and an extrusion pelletizer to obtain pellets.
-450), barrel temperature 185°C, injection pressure 1
40Kg/ei! A 300 g box-shaped fax housing part was injection molded at a mold temperature of 40'C and the conditions shown in Table 1. The resin filling time, the temperature of the resin discharged from the nozzle, and the filling rate during injection molding were measured and are shown in Table 1. In addition, the appearance of the obtained sample was observed and the physical properties were measured, and the results are shown in Table 1.

(Left below) Table 1 Degree of polymerization: 500, chlorine content: 61% (2) Degree of polymerization: 50
0, chlorine content 65% polymerization degree 500, chlorine content 67% AN content 24%, St content 31%, rubber content 45%, specific viscosity 0.63 AN content 24%, St content 76%, weight average molecular weight 65, 000 (Effects of the Invention) The structure of the vinyl chloride resin composition of the present invention is as described above, and it has excellent thermal stability and thermal fluidity, and can be easily injection molded without burning etc. The molded product obtained by injection molding has excellent flame retardancy, chemical resistance, heat resistance, etc., and is suitably used for housings of OA equipment, interior parts of automobiles, etc.

Claims (1)

[Claims] 1. (a) 40 to 80 wt% of a vinyl chloride resin having an average chlorine content of 60 to 70 wt%; (b) an ABS resin;
One or more impact modifiers selected from the group consisting of MBS resin, chlorinated polyethylene, and acrylic rubber resin5-
(c) 100 parts by weight of a resin composition consisting of 0 to 40 wt% of a styrenic copolymer obtained by copolymerizing a styrene compound and a vinyl cyanide compound; and (d) 2.5 to 6 parts by weight of calcium stearate. A vinyl chloride resin composition comprising: 2. (a) 40 to 80 wt% of vinyl chloride resin with an average chlorine content of 60 to 70 wt%, (b) ABS resin,
One or more impact modifiers selected from the group consisting of MBS resin, chlorinated polyethylene, and acrylic rubber resin5-
(c) 100 parts by weight of a resin composition consisting of 0 to 40 wt% of a styrenic copolymer obtained by copolymerizing a styrene compound and a vinyl cyanide compound; and (d) 2.5 to 6 parts by weight of calcium stearate. A molded article obtained by injection molding a vinyl chloride resin composition comprising: