JP2002194099A - Heat resistant vinylchloride resin pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat resistant vinylchloride resin pipe with high heat resistance and improved in impact resistance and mechanical strength. SOLUTION: This heat resistant vinylchloride resin pipe is characterized by stretching a resin pipe at least in the circumference direction of the pipe at 120 to 170 deg.C at a stretching ratio of 1.3 to 10 times in the circumference direction and 1 to 10 times in the axial direction, where the pipe is obtained by molding a vinylchloride-based resin composition comprising 100 pts.wt. of a chlorinated vinylchloride resin containing 60 to 71 wt.% chlorine and the average degree of polymerization of original vinylchloride resin before chlorination being 600 to 1,400 and 2 to 20 pts.wt. of a methylmethacrylate-butadiene- styrene copolymer (referred to as MBS).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat-resistant vinyl chloride resin tube obtained by molding a chlorinated vinyl chloride resin composition.

[0002]

2. Description of the Related Art A molded article of vinyl chloride resin has mechanical strength,
Utilizing excellent properties such as chemical resistance and oil resistance, for example,
It is widely used for building materials, water supply, agricultural, industrial pipes and joints, flat plates, etc., and is also used in applications requiring heat resistance.

As a method for improving the heat resistance of a vinyl chloride resin molded product, there is a method of producing a molded product using a chlorinated vinyl chloride resin composition obtained by chlorinating a vinyl chloride resin. By this method, it is possible to use the polyvinyl chloride resin molded product, for example, for hot water supply pipes, fire extinguishing sprinkler piping materials, industrial piping materials, industrial boards, etc., and cannot be used with conventional vinyl chloride resin molded products. It has become possible to use various molded products in various application fields or use environments.

Japanese Patent Application Laid-Open No. 10-296821 proposes a resin pipe using a chlorinated vinyl chloride resin in order to improve impact resistance. However, if the mechanical strength and heat resistance other than impact resistance decrease, the creep property and water pressure resistance decrease, so when used as a hot water supply pipe, fire extinguisher sprinkler piping material, industrial piping material, its use environment, There is a problem that the life is greatly limited. As described above, the pipe formed using the chlorinated vinyl chloride resin molded article has a problem that the impact resistance and the effect of suppressing crack propagation are not sufficient.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a heat-resistant vinyl chloride resin having high heat resistance and improved impact strength and mechanical strength. To provide tubes.

[0006]

The heat-resistant vinyl chloride resin tube of the present invention has a chlorine content of 60 to 71% by weight and an average degree of polymerization of the vinyl chloride resin before chlorination of 600 to 140.
A resin obtained by molding a vinyl chloride resin composition comprising 100 parts by weight of a chlorinated vinyl chloride resin which is 0, and 2 to 20 parts by weight of a methyl methacrylate-butadiene-styrene copolymer (hereinafter referred to as "MBS"). Tubes 120-
The film is stretched at least in the circumferential direction at 170 ° C., and the stretching ratio is 1.3 to 10 times in the circumferential direction of the tube and 1 to 10 times in the axial direction of the tube.

Hereinafter, the configuration of the present invention will be described in detail. The chlorinated vinyl chloride resin used in the present invention has a chlorine content of 60 to 71% by weight and an average degree of polymerization of the chlorinated vinyl chloride of 600 to 1400.

As the chlorination method of the vinyl chloride resin, a conventionally known water suspension method, solution chlorination method and the like are used, but the water suspension method is industrially preferable. As a method of adjusting the chlorine content to the above range, it may be adjusted at the reaction stage, or may be adjusted by blending a vinyl chloride resin having a high chlorine content and a vinyl chloride resin having a low chlorine content. Good.

The vinyl chloride resin before being chlorinated as described above includes a vinyl chloride homopolymer, a copolymer with a copolymerizable monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer, and a vinyl chloride monomer as the polymer. And a graft copolymer obtained by graft copolymerizing the above.

In the present invention, these polymers may be used alone or in combination of two or more. As the polymerization method, conventionally known bulk polymerization, solution polymerization, emulsion polymerization and the like are used, and the above-mentioned degree of polymerization is adjusted in the polymerization stage.

Examples of the copolymerizable monomer having an unsaturated bond copolymerizable with vinyl chloride include α-olefins such as ethylene, propylene and butylene; vinyl acetate;
Vinyl esters such as vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl acrylate and phenyl methacrylate; styrene, α-
Aromatic vinyls such as methylstyrene; vinylidene chloride;
Vinyl halides such as vinylidene fluoride; N-phenylmaleimide and N-cyclohexylmaleimide;
Substituted maleimides and the like are used, and one or more of these are used.

The polymer for graft-copolymerizing vinyl chloride is not particularly limited as long as it is capable of graft-polymerizing vinyl chloride. For example, ethylene-vinyl acetate copolymer; ethylene-vinyl acetate-carbon monoxide Copolymer; ethylene-ethyl acrylate copolymer; ethylene-butyl acrylate-carbon monoxide copolymer; ethylene-methyl methacrylate copolymer; ethylene-propylene copolymer; acrylonitrile-butadiene copolymer; polyurethane; Chlorinated polypropylene and the like. These may be used alone,
Two or more kinds may be used in combination.

In the present invention, the chlorine content of the chlorinated vinyl chloride resin must be 60 to 71% by weight.
Preferably, it is 62 to 68% by weight. Chlorine content is 6
If it is less than 0% by weight, sufficient heat resistance cannot be obtained.
If the content is more than 50% by weight, the moldability becomes difficult.

[0014] The chlorine content is determined by neutralization by the oxygen flask combustion method in accordance with JIS K7229.

In the present invention, the average degree of polymerization represents the average degree of polymerization of the vinyl chloride resin before chlorination and is determined by a solution viscosity method and must be 600 to 1400. Preferably it is 700-1100. If the average degree of polymerization of vinyl chloride before chlorination is less than 600, elongation characteristics at the stretching temperature are deteriorated, cracks are easily generated during stretch molding, and the impact strength of the molded product may be reduced. On the other hand, if it is larger than 1400, the formability of the original tube before stretching may be deteriorated.

In the present invention, the amount of MBS added is 2 to 2
It is limited to 0 parts by weight. If the addition amount is 2 parts by weight or less, impact resistance may not be sufficiently exhibited or uniform stretching may be difficult, and if it exceeds 20 parts by weight, the load during molding may increase. Sometimes.

The chlorinated vinyl chloride resin composition used in the present invention may contain, if necessary, a polyvinyl chloride resin, a heat stabilizer such as an alkyltin mercapto compound or an alkyltin malate, di-2-ethylhexyl phthalate (DOP). ), Plasticizers such as 2-ethylhexyl adipate (DOA); lubricants such as polyethylene-based wax, ester-based wax, stearic acid, montanic acid-based wax, and calcium stearate; An inorganic filler such as calcium carbonate, talc, clay, mica, and a processing aid such as a methacrylate resin;
It is manufactured by uniformly mixing each component by a conventionally known means.

The above chlorinated vinyl chloride resin composition is formed into a resin tube as a raw tube by using a conventionally known molding method such as extrusion molding, and then the raw tube is cooled in a temperature range of 120 to 170 ° C. The heat-resistant vinyl chloride resin tube of the present invention is manufactured by stretching.

The stretching method in the present invention is not particularly limited. For example, a method for stretching a raw tube at a stretching temperature of 120 ° C. to 170 ° C. in a circumferential direction or in a circumferential direction and an axial direction by a stretching mold, air or the like. The original tube is stretched with liquid at a temperature of 120.
A method of stretching in the circumferential direction, or in the circumferential and axial directions by heating and pressurizing to 120 ° C to 170 ° C,
A method of stretching a billet by extruding the billet at 70 ° C. by solid is exemplified.

The stretching ratio is from 1.3 to 1.3 in the circumferential direction of the tube.
It is limited to 10 times and 1 to 10 times in the tube axis direction. If the stretching ratio is small, the improvement in mechanical properties is small and the effect of suppressing crack propagation is also small. If the stretching ratio is large,
Stretch forming becomes difficult, and the elongation of the tube is reduced, and the tube is weakened against displacement and easily broken. In the present invention, the stretching ratio refers to the rate of change in outer diameter of the pipe (OD
1 / OD0 OD1: Outer diameter of pipe after drawing, OD0: Outer diameter of original pipe before drawing, and rate of change in pipe length in the pipe axis direction (L1 / L0 L1: Length of pipe after drawing, L0: Length of the tube before stretching) was calculated.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically with reference to the following examples. The present invention is not limited by these examples. (Examples 1 to 3, Comparative Examples 1 to 3) A predetermined amount of a chlorinated vinyl chloride resin shown in Table 1 (trade name "H" manufactured by Tokuyama Sekisui Industry Co., Ltd.)
A-52K ”average degree of polymerization before chlorination 1000, chlorine content 67% by weight, polyvinyl chloride resin (manufactured by Tokuyama Sekisui Industry Co., Ltd., trade name“ TS-1000R ”, average degree of polymerization 100)
0), MBS (Kanebuchi Chemical Industry Co., Ltd., trade name "M-51")
1)), tin-based heat stabilizer (trade name “J
F-10B "," OMF "), stearic acid (manufactured by NOF CORPORATION, trade name" Sakurain stearic acid "), polyethylene lubricant (manufactured by Mitsui Petrochemical Co., Ltd., trade name" Hiwax220M ")
P ”) was heated to 120 ° C. with a Henschel mixer and mixed to prepare a resin composition.

The above resin composition was supplied to a twin screw extruder having a screw diameter of 90 mm to extrude each raw tube having an outer diameter such that the draw ratio shown in Table 1 was obtained. Then, the inner diameter 1
It is set in a 14 mm, 2 m long mold, the inner and outer surfaces of the original tube are heated to 120 to 170 ° C. with polyethylene glycol, and the inside is stretched to 114 mm in outer diameter and 3.5 mm in thickness by pressurizing the inside with a pump The molded resin tube was molded.

The following evaluation items were tested for the obtained resin pipes, and the results are shown in each table. "Evaluation items" Appearance after stretching: Observed visually and evaluated according to the following evaluation criteria. ：: The wall thickness accuracy is equivalent to the wall thickness accuracy of the original tube, and the inner and outer surfaces are excellent in smoothness. ×: The wall thickness accuracy is worse than the wall thickness accuracy of the original tube, or a locally thin portion is generated. Vicat softening temperature: JIS K 7206 (1K
g load)

Stretching magnification: circumferential direction rate of change in outer diameter of pipe (OD1 / OD0, OD1: outer diameter of pipe after drawing, OD0: before drawing, OD0: outer diameter of original pipe) Axial direction pipe length change rate (L1 / L0, L1: length of tube after stretching, L0: length of tube before stretching)

Dropping impact value: A 25 cm short tube of a test specimen was conditioned at 0 ° C. for 60 minutes, and a 50% breaking height when a 9 kg column-shaped heavy cone was dropped was measured in accordance with JIS K7211. Breaking water pressure: A water pressure was applied to a short pipe of 1 m at room temperature as a test body, and the pressure at which the pipe was broken was measured.

[0026]

[Table 1]

[0027]

According to the present invention, it is possible to provide a heat-resistant vinyl chloride resin tube having excellent heat resistance and improved impact strength and mechanical strength.

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Claims (1)

[Claims] 1. The method according to claim 1, wherein the chlorine content is 60 to 71% by weight and the average degree of polymerization of the vinyl chloride resin before chlorination is 600 to 14%.
100 parts by weight of a chlorinated vinyl chloride resin, and a methyl methacrylate-butadiene-styrene copolymer 2
A resin tube obtained by molding a chlorinated vinyl chloride-based resin composition of from 20 to 20 parts by weight is stretched at least in the circumferential direction at 120 to 170 ° C, and the stretching ratio is 1.3 to 1.3 in the circumferential direction.
A heat-resistant vinyl chloride resin tube characterized in that the ratio is 10 times and 1 to 10 times in the tube axis direction.