JPH08113685A - Heat resistant vinyl chloride resin composition - Google Patents

Abstract

(57) [Summary] [Objective] To provide a heat-resistant vinyl chloride resin composition which can be easily molded by an ordinary vinyl chloride molding method and the resulting molded product is excellent in impact resistance and heat resistance. [Structure] Chlorinated vinyl chloride resin having a chlorine content of 59 to 71% by weight, a weight average molecular weight of 50,000 to 400,
000, chlorination degree 37-55% by weight and residual crystallinity 3
-20% chlorinated polyethylene as well as methyl methacrylate-butadiene-styrene copolymer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat resistant vinyl chloride resin composition.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resin takes advantage of its high heat resistance, and it is difficult to use conventional vinyl chloride resin because it is deformed by heat. It is used for hot water supply pipes at around 70-80 ° C. However, in such a hot water supply pipe,
It is known that when used at high temperature for a long period of time, it deteriorates due to hot water and leads to destruction. Specific examples of such a phenomenon include expansion deterioration and cracking due to water absorption.

Generally, a chlorinated vinyl chloride resin has a high tensile strength as compared with a normal vinyl chloride resin because of its rigid molecular chain, but has a problem of poor impact resistance. This is because the workability of the chlorinated vinyl chloride resin is poor, that is, it is difficult to disintegrate or fuse the chlorinated vinyl chloride particles. That is, the poor kneadability causes poor gelation and the original strength of the resin is not expressed.

Generally, impact modifiers are added to improve the impact strength of chlorinated vinyl chloride resins. Such impact modifiers include methyl methacrylate-butadiene-styrene copolymers; acrylic toughening agents; NB
Reinforcing agents such as R and ABS; chlorinated polyethylene and the like can be mentioned, and these impact modifiers are added in an amount of 3 to 15 parts by weight based on 100 parts by weight of the resin.

However, the above-mentioned acrylic reinforcing agent,
The reinforcing agents such as NBR and ABS have a problem that a large amount of them must be added in order to improve the impact resistance of a chlorinated vinyl chloride resin having a high degree of chlorination.

In addition, the addition of these impact modifiers often causes other problems. That is, in the methyl methacrylate-butadiene-styrene copolymer, by increasing the ratio of the butadiene rubber component,
Although it is possible to improve impact strength, an increase in the butadiene rubber component causes an extra load during processing, so
In addition to the high load peculiar to chlorinated vinyl chloride resin, there is a problem that an extra load is added. Further, by increasing the ratio of the butadiene rubber component, there is a problem that shearing between the resins increases and heat generation increases, so that decomposition occurs during molding and the thermal stability of the molded body is lost.

The above-mentioned chlorinated polyethylene is usually a polymer having a molecular weight of about 300,000, a chlorination degree of about 35% by weight, and almost no residual crystals, and exhibits strength without impairing the moldability of the vinyl chloride resin. Because you can
It is used for many purposes. However, when adding chlorinated polyethylene to chlorinated vinyl chloride resin,
Since it is processed at high temperature and high shear, there is a problem that the rubber elasticity of chlorinated polyethylene is difficult to be expressed.

In order to solve the above-mentioned problems, it is possible to add a large amount of the above-mentioned impact modifier together with a lubricant, a processing aid, a stabilizer and the like. However, addition of a large amount causes a decrease in heat resistance and an extrusion amount. However, there is a problem in that it causes a decrease in cost and an increase in cost.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and the object of the present invention is to obtain a product which can be easily molded by an ordinary vinyl chloride molding method. A molded article is to provide a heat resistant vinyl chloride resin composition having excellent impact resistance and heat resistance.

[0010]

[Means for Solving the Problems]

The heat-resistant vinyl chloride resin composition of the present invention comprises a chlorinated vinyl chloride resin, chlorinated polyethylene and a methyl methacrylate-butadiene-styrene copolymer.

The above chlorinated vinyl chloride resin (hereinafter referred to as CP
The degree of chlorination of VC) is 59 to 71% by weight. The chlorination degree is determined by the required heat resistance,
As the chlorination method, various methods such as a conventionally known water suspension method and solution chlorination method can be used, but the water suspension method is industrially preferable.

When the degree of polymerization of CPVC is small, the physical properties of the molded article deteriorate, and when it is large, molding becomes difficult. Therefore, the average degree of polymerization of the vinyl chloride resin before chlorination is 800 to 1,400. Preferably 9
It is 00 to 1,100.

As the vinyl chloride resin before chlorinating the CPVC, those known in the art can be used, for example, vinyl chloride homopolymers, vinyl chloride and polymerizable substances other than vinyl chloride. Examples thereof include a copolymer with a monomer and a graft copolymer obtained by grafting vinyl chloride on a polymer other than vinyl chloride.

The polymerizable monomer other than vinyl chloride is not particularly limited as long as it has a reactive double bond and can be copolymerized with vinyl chloride by a radical polymerization initiator. , Propylene, butylene, etc.
Olefins; vinyl acetates such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl acrylate and phenyl methacrylate. Aromatic vinyls such as styrene and α-methylstyrene; Vinyl halides such as vinylidene chloride and vinyl fluoride; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide. May be used alone or in combination of two or more.

The polymer other than vinyl chloride used in the graft copolymer is not particularly limited, and examples thereof include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene. -Ethyl acrylate copolymer, ethylene-ethyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer and the like, these are used alone. Or two or more kinds may be used in combination.

If the weight average molecular weight of the above chlorinated polyethylene (hereinafter referred to as CPE) is small, the impact strength of the molded article is reduced, and if it is large, the effect of improving the impact strength of the molded article is not exhibited. Therefore, it is 50,000 to 400. 1,000
And preferably 150,000 to 350,000.
0. The weight average molecular weight is a polystyrene equivalent value measured by GPC.

When the chlorination degree of the above CPE is low, it has a bad influence on the physical properties and appearance of the molded article, and when it is high, it is CPVC.
Since the compatibility with and improves the moldability improving effect, it is limited to 37 to 55% by weight.

The residual crystallinity of the CPE can be adjusted by the reaction temperature of chlorination, and is measured by a differential scanning calorimeter (DSC).
Is calculated by measuring the heat of fusion of the peak near the melting point of polyethylene using. The chlorination reaction temperature is
Usually, it is carried out in the range of 80 to 120 ° C., and the residual crystals decrease when the temperature is raised.

The above-mentioned residual crystallinity has a great influence on the formability of CPVC, and when it is small, the gelling time is delayed, so that the effect of improving the formability is lowered, and when it is larger, the chlorination distribution is biased and the formability is increased. It is limited to 3 to 20% by weight because the improvement effect and the physical properties decrease.

When the amount of the CPE used is small, the effect of improving the moldability is not exhibited, and when it is large, the gelation is suppressed and the physical properties are deteriorated. Therefore, the amount is 0.1 to 10 parts by weight based on 100 parts by weight of CPVC. Limited, preferably 2-5
Parts by weight.

As a chlorination method for obtaining the above CPE, a usual suspension method carried out in water is preferable in terms of cost and productivity. Further, as a method for performing chlorination in a more uniform manner in a short time, reaction at high temperature, irradiation with ultraviolet rays, etc. can be mentioned.

In order to further improve the impact resistance of the CPVC, a methyl methacrylate-butadiene-styrene copolymer (hereinafter referred to as MBS) is added in addition to the CPE. The MBS may be an impact modifier used for ordinary vinyl chloride resins, for example, "BTA" manufactured by Kureha Chemical Industry Co., Ltd., "B-56" manufactured by Kanebuchi Chemical Industry Co., Ltd.,
Examples of commercially available products include "Metabrene C" manufactured by Mitsubishi Rayon Co., Ltd.

The amount of MBS used is limited to 3 to 20 parts by weight with respect to 100 parts by weight of CPVC, because the effect of improving impact resistance is not exhibited when the amount is reduced and the moldability is decreased when the amount is increased.

In the heat-resistant vinyl chloride resin composition of the present invention, if necessary, di-2-ethylhexyl phthalate (DOP) and di-2-ethylhexyl adipate (DO).
Plasticizers such as A); lubricants such as polyethylene wax, stearic acid, montanic acid wax, calcium carbonate;
In addition, pigments, fillers such as glass fibers, antistatic agents, flame retardants, processing aids, and ultraviolet absorbers may be added.

The heat-resistant vinyl chloride resin composition of the present invention can be molded by a usual molding method of vinyl chloride resin such as an extrusion molding method, an injection molding method and a hot press molding method.

[0027]

Next, embodiments of the present invention will be described. Preparation of chlorinated polyethylene Weight average molecular weight 2.2 × 10 ⁵ , density 0.96 (g / c
m ³ ), 100 parts by weight of polyethylene having an average particle size of 100 μm were charged into a pressure reactor (capacity: 3 liters) provided with an inner surface glass lining equipped with a stirrer, and further 800 parts by weight of ion-exchanged water, ethylene oxide-propylene block Polymer (molar ratio 1: 1, weight average molecular weight 8,000
0) 0.2 parts by weight and 5 parts by weight of an aqueous ammonium salt solution of a methyl methacrylate-acrylic acid copolymer (molar ratio 1: 1, molecular weight 15,000, solid content concentration 30% by weight) were added. Then, after performing a chlorination reaction at a predetermined reaction temperature and a reaction time shown in Table 1 while blowing a chlorine gas until a predetermined chlorine content shown in Table 1 is obtained, the obtained resin is washed, After drying, white powdery CPE (A to F in the table) was obtained. In addition, the crystallinity of the obtained CPE is
It was calculated from the heat of fusion peak near the melting point of polyethylene measured by the DSC method and is shown in Table 1.

[0028]

[Table 1]

(Examples 1 to 5 and Comparative Examples 1 to 6) 100 parts by weight of a predetermined amount of chlorinated vinyl chloride resin shown in Tables 2 and 3, organotin mercapto ("JF-10" manufactured by Sansha Machine Synthesis Co., Ltd.).
B ") 2 parts by weight, stearic acid 1 part by weight, lubricant (" WaxOP "manufactured by Hoechst) 0.8 part by weight, and oxidized polyethylene lubricant (Mitsui Petrochemical" Hiwax 220 ").
1.2 parts by weight and the predetermined amount of M shown in Tables 2 and 3
BS and CPE were kneaded with a Henschel mixer at 120 ° C. and then cooled to 40 ° C. to obtain a heat resistant vinyl chloride resin composition.

After the above resin composition was kneaded with a mixing roll at 200 ° C. for about 3 minutes to obtain a sheet, 150 kg /
A plate having a thickness of 3 mm was produced by press molding at cm ² for 4 minutes.

Regarding the heat-resistant vinyl chloride resin compositions and plates obtained in the above Examples and Comparative Examples, the following (1)
The physical properties of (4) to (4) were measured and the moldability was evaluated, and the results are shown in Tables 2 and 3. (1) Impact resistance The Charpy impact strength of the plate was measured according to JIS K7110. (2) Heat resistance According to JIS K7206, the Vicat softening temperature of the plate was measured. (3) Moldability Evaluation A steady torque at 200 ° C. of the heat resistant vinyl chloride resin composition was measured using a torque rheometer (manufactured by Haake). (4) Extrudability evaluation A heat-resistant vinyl chloride resin composition was extrusion-molded using a 50 mm bi-directional extruder, and the resulting pipe (molded body) was obtained.
The appearance was evaluated by visual observation, and those having no problem in appearance were evaluated as ◯, those having slight streaks or waviness in appearance were evaluated as Δ, and those having poor appearance were evaluated as ×.

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

The constitution of the heat-resistant vinyl chloride resin composition of the present invention is as described above, and it can be easily molded by the usual molding method of vinyl chloride resin. Since it has excellent properties, heat resistance and appearance, it can be suitably used for applications requiring heat resistance such as hot water supply pipes.

Claims (1)

[Claims] 1. A chlorinated vinyl chloride resin having a chlorine content of 59 to 71% by weight and a weight average molecular weight of 50.0.
Chlorinated polyethylene having a chlorination degree of 37 to 55% by weight and a residual crystallinity of 3 to 20% by weight.
A heat resistant vinyl chloride resin composition comprising 1 to 10 parts by weight and 3 to 20 parts by weight of a methyl methacrylate-butadiene-styrene copolymer.