JPH05170932A - Tubular polypropylene resin molding for watersupply and drainage - Google Patents

Abstract

PURPOSE:To provide a tubular polypropylene resin molding for watersupply and drainage, having improved durability and resistant to the deterioration of the resin e.g. in the use as a water-supply and drainage pipe or joint. CONSTITUTION:The objective molding is composed of a polypropylene resin composition produced by compounding (A) 100 pts.wt. of a polypropylene resin with (B) 0.05-3 pts.wt. of 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane and 0.05-3 pts.wt. of a dialkyl-3,3'-thiodipropionate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin tubular molded article for water supply and drainage, and in particular, it is prevented from being deteriorated when used for non-circulating system water supply and drainage piping such as tap water, rainwater, and sewage. The present invention relates to a tubular molded body for water supply and drainage having improved durability.

[0002]

2. Description of the Related Art Conventionally, hard polyvinyl chloride resin and high-density polyethylene resin have been mainly used as plastics for water supply and drainage pipes and joints having an inner diameter of about 100 mm or more, but the former has poor impact resistance. Therefore, there is a drawback that the pipe is easy to break during transportation and construction, and the latter has a drawback that the pipe is easily flattened when buried in the soil due to its poor rigidity.

On the other hand, there is polypropylene resin as a plastic that can provide a material that eliminates the drawbacks of both resins at the same time. However, polypropylene resin is particularly useful for use in water supply / drainage of non-circulating systems such as tap water, rain water, and sewage. There is a problem that it deteriorates early. Then, conventionally, for example, tetrakis [methylene-3- (3 ', 5'
-Di-t-butyl-4'-hydroxyphenyl) propionate] A method of preventing deterioration of the polypropylene resin by contact with water by adding an antioxidant such as methane has been proposed, but it can still be put to practical use. At present, the degree of improvement has not been reached.

[0004]

SUMMARY OF THE INVENTION In view of the above situation, the present inventors have made diligent studies to prevent deterioration of the resin when using a water / drainage pipe made of polypropylene resin, a tubular molded body for water supply / drainage such as a joint. By using an antioxidant compounded with polypropylene resin as a combination system of specific antioxidants, not only for hot water supply of circulating system, but also for non-circulating water supply / drainage of tap water, rainwater, sewage, etc. It has also been found that the deterioration of the resin can be prevented, and the present invention has been achieved. Therefore, the present invention prevents the deterioration of the resin when used as a pipe for water supply and drainage, a joint, etc. It is an object of the present invention to provide an improved polypropylene resin tubular molded article for water supply and drainage.

[0005]

Means for Solving the Problems The polypropylene resin tubular molded article for water supply and drainage of the present invention is made of polypropylene resin,
It is characterized by being molded from a polypropylene resin composition in which each of the following components (A) and (B) is blended in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the resin. (A) 3,9-bis {2- [3- (3-t-butyl-4
-Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-
Tetraoxaspiro [5.5] undecane and 1,
At least one compound selected from the group consisting of 3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (B) dialkyl-3,3 ′ -Thiodipropionate,
And at least one compound selected from the group consisting of pentaerythritol-tetra (β-alkyl-thiopropionate) (wherein the alkyl group has 12 to 18 carbon atoms).
Is. )

The polypropylene resin used in the present invention is a homopolymer of propylene, propylene and ethylene, butene-1, pentene-1, hexene-1,4-.
Α-Olefins such as methyl-pentene-1, unsaturated carboxylic acids such as acrylic acid, ethyl acrylate, maleic anhydride and their derivatives, vinyl esters such as vinyl acetate and vinyl butyrate, unsaturated fragrances such as styrene and methylstyrene. Random, block, or graft copolymers with group compounds, and the like. Of these, a propylene-ethylene block copolymer is preferable.

In the present invention, the component (A) blended with the polypropylene resin is 3,9-bis {2-
[3- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.
5] Undecane and 1,3,5-trimethyl-2,
It is at least one compound selected from the group consisting of 4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, and compounds other than these are the same as those used as a tubular molded body. The effect of preventing deterioration of polypropylene resin cannot be obtained.

The component (B) to be blended with the polypropylene resin in the present invention is a dialkyl-3,3'-thiodipropionate having an alkyl group of 12 to 18 carbon atoms and pentaerythritol. -At least one compound selected from the group consisting of tetra (β-alkyl-thiopropionate), in a combination system with the component (A), when other compounds are used as a tubular molded body. The effect of preventing deterioration of the polypropylene resin cannot be obtained.

Specific examples of these components (B) include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate and distearyl-.
3,3′-thiodipropionate, lauryl stearyl-3,3′-thiodipropionate, pentaerythritol-tetra (β-lauryl-thiopropionate), pentaerythritol-tetra (β-stearyl-thio) Propionate) and the like, among which, distearyl-
3,3'-thiodipropionate and pentaerythritol-tetra (β-lauryl-thiopropionate) are preferred.

In the present invention, the component (A), and
The blending amount of the component (B) is 100% of the polypropylene resin.
0.05 to 3 parts by weight with respect to 0 parts by weight, and 0.
It is preferably from 1 to 1 part by weight. If the amount of both components (A) and (B) is less than this range, the effect of preventing deterioration of the polypropylene resin will be insufficient, while if the amount exceeds the range, bleed-out on the surface of the molded product and coloring of the molded product itself will occur. Problems such as occur.

The polypropylene resin composition constituting the polypropylene resin tubular molded body for water supply and drainage of the present invention essentially consists of the polypropylene resin mixed with the components (A) and (B). You may mix an additional component. Examples of the additional component include an antioxidant other than the components (A) and (B), a light stabilizer, a neutralizer, a lubricant, an antistatic agent, a metal deactivator, a colorant, a dispersant, There are nucleating agents, fillers, resins other than the polypropylene resin, rubber and the like.

In particular, 2,6-di-t is used as an antioxidant.
-Butylphenol, 4,4'-thiobis (3-methyl-6-t-butylphenol), 4,4'-butylenebis (3-methyl-6-t-butylphenol), 2,
2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-ethylidenebis (4,6-di-t)
-Butylphenol), hindered phenolic compounds such as d, l-α-tocopherol, tris (mixed-mono and di-nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, Bis (2,4-di-t-butylphenyl) pentaerythritol-diphosphite, tetrakis (2,4)
-Di-t-butylphenyl) 4-4'-biphenylene-
Aromatic phosphorus compounds such as diphosphonite are added in an amount of 0.001-1 based on 100 parts by weight of the polypropylene resin.
By blending parts by weight, it is possible to improve the stability against deterioration when the polypropylene resin composition is molded into the tubular molded product of the present invention.

Further, as a filler, 5 to 30 parts by weight of talc, mica, glass fiber or the like is mixed with 100 parts by weight of the polypropylene resin to improve the flatness resistance of the tubular molded article of the present invention. You can Resin, rubber as an additional component, low / medium / high density polyethylene, polybutene, ethylene-propylene copolymer rubber,
Examples thereof include ethylene-butene copolymer rubber. In the present invention, tubular moldings such as pipes and joints are molded from the polypropylene resin composition by a conventional method such as extrusion molding.

[0014]

EXAMPLE A propylene-ethylene block copolymer resin (melt flow rate 0.5 g / 10 min) was mixed with the resin 1
A composition obtained by mixing various parts such as the various antioxidants shown in Table 1 with 100 parts by weight in an amount of 40 parts by weight using a 40 mm diameter extruder (L / D = 24) was used. It was extruded at 0 ° C., and a straight pipe having an outer diameter of 27 mm and a wall thickness of 2 mm was molded by water cooling to obtain a polypropylene resin tubular molded body for water supply and drainage.

Each of the obtained tubes was cut into a length of 300 mm, and 80 ° C. clean water (oxygen content 7 ppm) was continuously passed through the tubes at a rate of 10 liters / hour. The temperature of the outside air at this time was also 80 ° C. After passing 5000 hours, stop the flow of water and visually observe the occurrence of cracks on the inner surface of the pipe. Furthermore, measure the time until brittle fracture in each air-circulated oven at 150 ° C for each pipe after passing water. did. The results are shown in Table 1.

[0016]

[Table 1]

The symbols of antioxidants in Table 1 indicate the following compounds, respectively. A-1; 3,9-bis {2- [3- (3-t-butyl-
4-Hydroxy-5-methylphenyl) propionyloxy] -1,1'-dimethylethyl} -2,4,8,1
0-Tetraoxaspiro [5.5] undecane A-2; 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene B-1; distearyl-3,3′-thiodipropionate B-2; pentaerythritol-tetra (β-lauryl-
Thiopropionate) C-1; tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane C-2; tris (2,4-di-t). -Butylphenyl) phosphite C-3; 2,6-di-t-butyl-4-methylphenol

[0018]

EFFECT OF THE INVENTION Since the polypropylene resin tubular molded article for water supply / drainage of the present invention is formed from a resin composition in which a specific amount of polypropylene resin is used in combination with a specific antioxidant, a water supply / drainage pipe, joint, etc. As a result, the resin is prevented from being deteriorated during use, and the durability is improved.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location C08L 51/06 LLD 7142-4J 53/00 LLW 7142-4J C08L 23:10 (72) Inventor Inagaki 1 Toho-cho, Yokkaichi-shi, Mie Prefecture Yokkaichi Research Institute, Mitsubishi Petrochemical Co., Ltd.

Claims (1)

[Claims] 1. A polypropylene resin containing 0.05 parts each of the following components (A) and (B) per 100 parts by weight of the resin.
A tubular molded body for water supply and drainage made of polypropylene resin, characterized by being molded from a polypropylene resin composition blended in an amount of 3 to 3 parts by weight. (A) 3,9-bis {2- [3- (3-t-butyl-4
-Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-
Tetraoxaspiro [5.5] undecane and 1,
At least one compound selected from the group consisting of 3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (B) dialkyl-3,3 ′ -Thiodipropionate,
And at least one compound selected from the group consisting of pentaerythritol-tetra (β-alkyl-thiopropionate) (wherein the alkyl group has 12 to 18 carbon atoms).
Is. )