JPS5938978B2 - thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin composition with excellent processability and heat resistance, and particularly to a thermoplastic resin composition that provides good surface gloss to molded articles obtained by injection molding and extrusion molding. relating to things.

A resin composition consisting of an acrylonitrile-chlorinated polyethylene-styrene three-component resin (hereinafter abbreviated as ACS resin) and a vinyl chloride resin is known as a composition with excellent impact resistance, weather resistance, and flame retardancy. It is being

However, since the heat resistance (heat distortion temperature) of the vinyl chloride resin is low, the heat resistance of this composition is lower than that of ACS resin, and this composition cannot be processed by extrusion processing, which is commonly used. However, depending on the molding conditions, the surface gloss of the resulting molded product may be impaired. In order to improve this drawback, a method is known in which, for example, a high molecular weight methyl methacrylate resin is blended into a composition consisting of an ACS resin and a vinyl chloride resin.

However, although this method has the advantage of having excellent surface hardness, tensile strength, and impact resistance, as well as improved surface gloss and heat resistance, it has drawbacks in processability (flow characteristics). As mentioned above, in conventional improvement methods, improving one physical property often results in a decrease in other physical properties.
It is extremely difficult to obtain a resin composition.

As a result of various studies on the heat resistance of a resin composition made of an ACS resin and a vinyl chloride resin and the surface gloss of a molded article, the present inventors discovered that it is possible to add a polyamide resin having a specific melting point to the composition. found that the processability and heat resistance of the composition and the surface gloss of the molded article were significantly improved, and that a molded article having good physical properties could be obtained,
We have arrived at the present invention.

In the present invention, 100 parts by weight of the resin composition contains (2) 5 to 45% of chlorinated polyethylene with a chlorine content of 20 to 50% by weight.
30 to 90 parts by weight of ACS resin containing % by weight, (B)
The present invention relates to a thermoplastic resin composition comprising 40 to 5 parts by weight of a vinyl chloride resin and (C) 30 to 5 parts by weight of a polyamide resin having a melting point of at most 230°C.

The ACS resin used in the present invention is a so-called graft type ACS resin obtained by polymerizing a mixed monomer of acrylonitrile and styrene in the presence of chlorinated polyethylene.
Resin (Japanese Patent Publication No. 39-17057) or so-called blended ACS resin obtained by mixing chlorinated polyethylene and acrylonitrile-styrene copolymer resin (Japanese Patent Publication No. 41
-6351), but in order to improve the heat resistance of ACS resin, some of the styrene is replaced with α-methylstyrene, and some of the acrylonitrile is replaced with methacrylate to improve the transparency. Substituting methyl acid may also be used.

The required amount of α-methylstyrene is 5 to 2 of the total monomer components.
0% by weight, and the required amount of methyl methacrylate is 20-80% by weight of the total monomer component. Hereinafter, all of these resins will be referred to as ACS resin. The raw material chlorinated polyethylene includes chlorinated polyethylene obtained by chlorinating polyethylene, chlorinated ethylene copolymers such as ethylene-propylene copolymer or ethylene-butene-1 copolymer, and chlorosulfonated polyethylene. things are also used.

Chlorinated polyethylene has a chlorine content of 20 to 50% by weight,
More preferably, 30 to 40% by weight is suitable for improving the impact resistance of the composition, and the proportion of chlorinated polyethylene in the ACS resin is 5 to 45% by weight, preferably 5 to 40% by weight. %. If the proportion of chlorinated polyethylene in the ACS resin exceeds 45% by weight, impact resistance will improve, but tensile strength will decrease. On the other hand, ACS
If the proportion of chlorinated polyethylene in the resin is 5% by weight or less, the ACS resin becomes hard and the tensile strength improves, but the impact resistance decreases, which is not preferable. The proportion of acrylonitrile and styrene in the ACS resin is 95 to 55% by weight, preferably 95 to 60% by weight, in which the ratio of acrylonitrile to styrene is selected in the range of 10 to 90% by weight. When the ratio of acrylonitrile increases, the tensile strength increases for the same amount of chlorinated polyethylene.
Impact resistance improves, and workability increases as the proportion of styrene increases. Furthermore, the vinyl chloride resin used in the present invention includes hard vinyl chloride resin having a degree of polymerization of 500 to 2,000, preferably 700 to 1,500, as well as vinyl chloride containing at least 80% by weight of vinyl chloride, vinyl acetate, vinylidene chloride, or It also includes copolymers with other vinyl monomers and post-chlorinated vinyl chloride resins.

The polyamide resin, which is yet another component used in the present invention, has a melting point of at most 230°C, preferably 150 to 230°C.

These polyamide resins are synthesized by polycondensation reaction according to conventional methods. The polyamide resins obtained in this way have various melting points depending on the types of diamines, dicarboxylic acids and lactams used, the mixing ratio of these monomers, etc., but if the melting point is too high, it will not be able to match ACS resins or vinyl chloride resins. It is impossible to intimately knead the polyamide resin due to the poor compatibility of the polyamide resin, and on the other hand, if the melting point becomes too low, the improvement effect of the present invention will be poor, so it is preferable to use a polyamide resin having the above melting point.

In carrying out the present invention, it is particularly preferable to use nylon 6, nylon 6/10, nylon 11, nylon 12, and the like. When preparing the desired resin composition by mixing the three components described above, the mixing ratio of each component is 30 to 30 parts by weight of (A) ACS resin in 100 parts by weight of the total composition.
90 parts by weight of the vinyl chloride resin, and 30 to 5 parts of the Q polyamide resin.

These mixing ratios were obtained as a result of various experiments and studies by the inventors, and were determined from the viewpoint of practicality of the composition based on processability, heat resistance, surface gloss of the molded product, and various other properties. This is a critical value. That is, if the mixing ratio of the ACS resin is less than 30 parts by weight, the processability will deteriorate, which is undesirable. On the other hand, if the mixing ratio of the ACS resin exceeds 90 parts by weight, the heat resistance will not be sufficient. In addition, if the mixing ratio of vinyl chloride resin exceeds 40 parts by weight, heat resistance will be poor;
If the mixing ratio of the vinyl chloride resin is less than 5 parts by weight, the flame retardance will decrease, which is not preferable. Furthermore, if the mixing ratio of the polyamide resin exceeds 30 parts by weight, flame retardancy and processability will deteriorate, which is undesirable.On the other hand, if the mixing ratio of the polyamide resin exceeds 5 parts by weight, surface gloss and heat resistance will be improved. The effect is not sufficient. The flame retardance of the resin composition of the present invention can be improved by further adding a flame retardant.

As the flame retardant, any known flame retardants such as halogenated esters, phosphoric acid esters, aromatic halides, etc. may be used, but in particular, the degree to which the antimony-based compound changes the various properties of the resin composition of the present invention may be used. It is preferably used because it is small in size and has the advantage of significantly improving flame retardancy due to its synergistic effect with chlorine. The amount of the antimony compound added is at most 20 parts by weight based on 100 parts by weight of the total amount of the composition. The composition of the present invention can be prepared by adding the specified ingredients using a conventional method such as using a hot roll, a Banbury mixer, or an extruder. At this time, various additives such as stabilizers, antioxidants, lubricants, plasticizers,
Antistatic agents, fillers, colorants, etc. can be added. The resin composition of the present invention has the above-mentioned properties, particularly excellent processability, heat resistance, and surface gloss, and is therefore suitable for use as internal parts of electrical equipment parts, such as calculators, copiers, registers, microwave ovens, etc. Useful.

The present invention will now be illustrated in detail with reference to Examples and Comparative Examples.

In the examples, parts are by weight unless otherwise specified. In addition,
Physical property values of the molding materials were determined according to the following. Surface Gloss The surface gloss of ASTM tampel No. 1 was measured using a Cardner crossmeter and expressed as light reflectance.

Heat resistance (heat distortion temperature) [1] According to ASTM D648-72, load 18.5 kg and 4
．． Measured at 6 kg.

Heat resistance (heat distortion temperature) [] Radio molding (210 x 100 x 60
mm1 average wall thickness 3 mm), and heated it at 80°C and 900°C.
C1100C, 1100C, and 120C, respectively, for 7 hours in an oven, and the deformation rate was measured.

Tensile strength ASTM D638 Impact resistance ASTM D256-73 Workability ASTM D1238-73, 190, C110k
It was measured with a load of g.

Combustion test Examples 1 to 8 and Comparative Examples 1 to 6 according to the UL-94 vertical combustion test method using a test piece with a flame retardant thickness of 1.6 m 1 L Chlorinated polyethylene with a chlorine content of 30% by weight (Showa Denko ), abbreviated as Erasuren 301AsCPE)
and acrylonitrile/styrene copolymer resin (composition ratio 25
ACS resin, polyvinyl chloride (Japan Zeo 7 Co., Ltd.) mixed with /75) to have the CPE content listed in Table 1.
manufactured by S9Ol, degree of polymerization 1000, abbreviated as PVC)
and polyamide resin (abbreviated as polyamide) as the first
Add to the ratio listed in the table, and add 65mmφ at 200℃.
The mixture was kneaded using an extruder (vent type).

At this time, 2 parts of dibutyltin maleinate is added to 100 parts by weight of the total amount of resin. Next, the composition was molded using a 3-ounce injection molding machine, the cylinder temperature was set at 16°C - 180°C - 20°C from the hopper part to the screw end, the injection pressure was 80kg/Cli, and the mold temperature was 50°C. were set, and each was molded into a predetermined test piece.

Using this test piece, gloss, heat resistance, tensile strength, and impact resistance tests were conducted. The mold for the radio for the heat resistance D test was made using a 10-ounce injection molding machine, and the cylinder temperature was controlled at 160°C (C) from the hopper part to the screw end.
1) -180°C (C2) -200°C (C3) -20'C
(C4) and was molded at an injection pressure of 100 kg/CTIl mold temperature of 5'C. In addition to these tests, for comparison, a product consisting of two components of ACS resin and PVC, AC
S resin with a CPE content outside the range of the present invention, PV
The blending amount of C is outside the range of the present invention, the blending amount of polyamide is outside the range of the present invention, the melting point of polyamide is outside the range of the present invention, and methyl methacrylate resin is blended with ACS resin and PVC. He did the same thing with things.

The results are shown in Table 1. The polyamide and methyl methacrylate resin used in these examples are
It is as follows.

As is clear from Table 1, all of the compositions of the present invention have improved gloss and heat resistance, and are well-balanced in terms of physical properties.

Examples 9 to 11, Comparative Example 7 The ratio of acrylonitrile to styrene was 25/75, and the content of chlorinated polyethylene (manufactured by Showa Denko K.K., Elasrene 301A1, chlorine content 30% by weight) in the resin composition was 40%. Graft type ACS resin, polyvinyl chloride (made by Nippon Zeo 7 Co., Ltd., S9Ol, degree of polymerization 1000)
, PVC) and nylon 12 were blended in the ratios shown in Table 2.

Claims (1)

[Claims] 1 100 parts by weight of the resin composition has (A) chlorine content 2
5-45% by weight of 0-50% chlorinated polyethylene
30 to 90 parts by weight of an acrylonitrile-chlorinated polyethylene-styrene ternary resin, (B) 40 to 5 parts by weight of a vinyl chloride resin, and (C) 30 parts by weight of a polyamide resin with a melting point of at least 230°C. 5 parts by weight of a thermoplastic resin composition.