KR100891705B1 - Polypropylene Resin Composition for Pipe and Heat Water Pipe Device - Google Patents

Abstract

The present invention relates to a polypropylene resin composition for pipes and hot water pipe apparatus, and more particularly, ethylene random polypropylene having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 10 mol%, and a melt index of 0.1 to 10 g / 10. The present invention relates to a polypropylene resin composition for pipes comprising a propylene block polypropylene having a ethylene content of 0.1 to 20 mol%, rubber and a heat stabilizer, wherein the resin composition of the present invention has improved pressure resistance, impact resistance, It has shrinkage rate, heat resistance and workability, and can be applied to pipes, hot water pipe apparatuses and pipe fittings and the like.

Pipe, Hot Water Pipe Arrangement, Ethylene Random Polypropylene, Ethylene Block Polypropylene

Description

Polypropylene Resin Composition for Pipe and Heat Water Pipe Device

The present invention relates to a polypropylene resin composition for pipes and hot water pipe devices, and more particularly to a polypropylene resin composition exhibiting improved heat resistance, impact resistance, pressure resistance, shrinkage and workability.

Conventionally, metal materials have been mainly used in pipe and hot water pipe devices, but they have been rapidly replaced with plastic materials in recent 20 years. This is because plastics are cheap, hygienic and environmentally friendly. In addition, plastic materials are non-toxic and chemically resistant, stable from stray currents, and resistant to condensation and low thermal conductivity, which minimizes heat loss. In addition, due to the improvement of the physical properties of the plastic material itself and the development of processing technology, the pressure resistance and long-term heat resistance of plastics are improved as pipe materials. Among them, the demand for ethylene random copolymerized polypropylene pipes is rapidly increasing not only in the European market, which is the pioneer of the pipe market, but also in the Middle East and China, and PVC, which is the most representative material among plastic pipes, is due to environmental problems. Due to the tendency to be replaced by polyethylene or polypropylene.

Conventionally, ethylene random copolymerized polypropylene or ethylene block copolymerized polypropylene resin was generally used alone for pipe production. When ethylene random copolymerized polypropylene is used alone, flexibility and high temperature pressure resistance are good, and when ethylene block copolymerized polypropylene is used alone, bending strength and impact strength are excellent. In addition, in terms of processability, ethylene random copolymerized polypropylene has a low processing temperature, and ethylene block copolymerized polypropylene is advantageous in terms of cooling rate and extrusion pressure.

On the other hand, the conventional polypropylene resin has a long-term heat resistance and the specificity of the opposite properties between ethylene random copolymerized polypropylene and ethylene block copolymerized polypropylene, despite the favorable physical properties such as long-term heat resistance, impact resistance, chemical resistance and processability It was difficult to achieve pressure resistance at the same time.

Therefore, much research has been done to overcome these disadvantages.

For example, Korean Patent No. 10-0267459 discloses a vinyl acetate content in a polypropylene copolymer having an ethylene content of 11 to 20 mol%, a weight average molecular weight of 300,000 to 700,000, and a melt index of 0.1 to 3.0 g / 10 minutes. Ethylene vinyl acetate having a weight average molecular weight of 20,000 to 60,000 and a melt index of 0.5 to 5.0 and a crosslinking agent such as di-tert-butyl peroxide and divinylbenzene. Although a method of manufacturing is proposed, this method has a problem of lowering the processability of the polypropylene resin.

In addition, Korean Patent Publication No. 1996-0001009 discloses stiffness and impact strength consisting of a polypropylene block copolymer having an ethylene content of 3 to 25%, an ethylene propylene rubber having a propylene content of 20 to 60%, and fine talc having an average particle diameter of 2 μm or less. Although the polyolefin resin composition excellent in this is disclosed, this resin composition is low in pressure resistance, and cannot be used for a pipe and a hot water pipe apparatus.

Meanwhile, Korean Patent Publication No. 1998-0009364 discloses 60 to 80% by weight of polypropylene having a melt flow index of 1 to 5g / 10 minutes, 10 to 30% by weight of ethylene-propylene rubber, and 5 to 20% by weight of ethylene alpha-olefin copolymer resin. A thermoplastic polypropylene resin composition comprising% is disclosed. The resin composition satisfies both high impact properties and high stiffness properties at room temperature or low temperature, and has excellent heat resistance and surface hardness and can be processed by injection molding. The pressure resistance of the resin composition is lowered and cannot be used for pipes and hot water pipe apparatuses.

Accordingly, the present inventors have diligently studied to solve the above-mentioned problems of the prior art, and as a result, by mixing ethylene block polypropylene, rubber, and heat stabilizer with ethylene random polypropylene exhibiting low-temperature melting characteristics, It was found that a propylene resin composition was obtained and the present invention was completed.

It is an object of the present invention to provide a polypropylene resin composition for pipe and hot water pipe devices with improved heat resistance, impact resistance and pressure resistance.

The polypropylene resin composition of the present invention is an ethylene random polypropylene having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 10 mol%, or a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 20 mol%. Polypropylene resin comprising phosphorus ethylene block polypropylene; 69.45-99.7 wt%, 0.1-30 wt% rubber, and 0.2-0.55 wt% heat stabilizer.

Hereinafter, the present invention will be described in detail.

In the present invention, the polypropylene resin is an ethylene random polypropylene having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 10 mol%, and an ethylene block having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 20 mol%. The polypropylene resin including polypropylene is used in the range of 69.45 to 99.7 weight% based on the total weight of the polypropylene resin composition of the present invention. When the ethylene content of the ethylene random polypropylene is 0.1 mol to 10 mol%, pressure resistance, impact resistance, etc. can be optimized. When the ethylene content is less than 0.1 mol%, pressure resistance and flexibility are lowered, and more than 10 mol%. In this case, flexural strength and impact resistance are reduced. In addition, when the ethylene content of the ethylene block polypropylene is 0.1 to 20 mol%, impact resistance and flexural strength may be optimized. That is, when the ethylene content is less than 0.1 mol%, the flexibility decreases, and when the ethylene content exceeds 20 mol%, the pressure resistance is lowered.

The rubber used in the present invention uses PP plastomer. The rubber is blended 0.1 to 30% by weight relative to the total weight of the polypropylene resin composition of the present invention to improve long-term pressure resistance, impact resistance and freeze resistance. When the blending ratio of the rubber is less than 0.1% by weight, the impact resistance is lowered. When the rubber is more than 30% by weight, the pressure resistance and the shrinkage rate are lowered.

The polypropylene resin composition of the present invention uses a heat stabilizer of 0.2 to 0.55% by weight based on the total weight of the polypropylene resin composition of the present invention. Preferred heat stabilizers include 3,3 ', 3', 5,5 ', 5'-nucleated-tert-butyl-a, a', a '-(mesitylene-2,4,6-triyl) tri- p-cresol is mentioned. When the heat stabilizer is used in the resin composition of the present invention in less than 0.2% by weight, there is a problem of lack of long-term pressure resistance due to lack of heat resistance, when used in excess of 0.55% by weight there is a problem in economic efficiency.

In addition, the polypropylene composition of the present invention is 1 ~ 98.7% by weight of ethylene random polypropylene having a melt index of 0.1 to 10g / 10 minutes, ethylene content of 0.1 to 10 mol%, a melt index of 0.1 to 10g / 10 minutes and an ethylene content of 0.1 1 mol% to 68.45 wt% of ethylene block polypropylene, ˜20 mol%, 0.1 to 30 wt% of rubber and 0.2 to 0.55 wt% of heat stabilizer.

On the other hand, the polypropylene composition of the present invention may be added to the polypropylene composition of the present invention, additives such as antioxidants, neutralizing agents such as molecular weight regulators, primary antioxidants and secondary antioxidants.

Polypropylene resin composition according to the present invention is excellent in heat resistance and pressure resistance, excellent flexural strength, can be easily adjusted to workability according to the user's use can be applied to various applications. In particular, the heating material may be used for pipes, pipe fittings, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples are provided to explain preferred embodiments of the present invention, and the scope of the present invention is not limited by the following examples.

Examples and Comparative Examples

The propylene-ethylene random copolymer resin having an ethylene content of 3.5 mol%, the propylene-ethylene block copolymer resin having an ethylene content of 8 mol%, rubber, an antioxidant and a heat stabilizer were heated to 210 ° C. in the composition ratios shown in Table 1 below. Into the twin-screw extruder and melt kneaded to produce an alloy of chip-like propylene-ethylene random copolymer resin and propylene-ethylene block copolymer resin, which was then heated at a temperature of 90 ° C. in a dehumidifying dryer for 5 hours. Dried over.

The physical properties of the dried chipped resins were evaluated according to the following physical property measurement method, and the results are shown in Table 1 below.

[Measurement of physical properties]

(1) Pressure resistance: The composition was extruded to prepare a pipe, and evaluated at 300C for 60 hours to measure the pressure resistance with or without abnormality of the pipe.

(2) Shrinkage rate: After a certain size of the specimen was stored at 60 ℃ for 72 hours, the change in length due to thermal expansion was measured.

(3) Impact resistance: According to ASTM D256, after the specimen was prepared in the pellet (Pellet) of the resin composition of the present invention, the impact resistance was measured.

(4) Flexural Strength: The flexural strength was measured after preparing the resin composition of the present invention in accordance with ASTM 790 as a specimen.

Ethylene Random Polypropylene ⁽¹⁾ Content (wt%) Ethylene Block Polypropylene ⁽²⁾ Content (% by weight) Rubber ⁽³⁾ Content (% by weight) Heat stabilizer ⁽⁴⁾ Content (% by weight) Pressure resistance (bar) Shrinkage (%) Impact resistance 23 / -10 ℃ (kgcm / cm) Flexural Strength (kg / cm ² ) Example 1 80 10 9.5 0.5 35.9 1.2 68.5 / 6.1 11,820 Example 2 70 20 9.5 0.5 33.1 1.2 68.2 / 6.3 11,200 Comparative Example 1 90.4 0 9.5 0.1 35.1 1.3 60.7 / 6.0 10,900 Comparative Example 2 0 90.4 9.5 0.1 23.5 1.4 70.1 / 6.1 13,100 Comparative Example 3 99.5 0 0 0.5 32.1 1.3 49.9 / 5.2 10,900 Comparative Example 4 0 99.5 0 0.5 29.3 1.2 69.0 / 6.0 13,200 Comparative Example 5 60 39.5 0 0.5 35.1 1.2 62.4 / 6.1 12,800 Comparative Example 6 65 25.4 9.5 0.1 32.1 1.2 70.8 / 7.1 11,200

Note: (1) Ethylene Random Polypropylene: Uses ethylene content of 3.5 mol% and melt index of 0.25 g / 10 min.

(2) Ethylene block polypropylene, which uses ethylene content of 8 mol% and melt index of 0.35 g / 10 minutes

(3) Rubber: PP Plastomer (Dow Co., d = 0.867g / ml)

(4) Heat stabilizers: 3,3 ', 3', 5,5 ', 5'-nucleated-tert-butyl-a, a', a '-(mesitylene-2,4,6-triyl) tree -p-cresol

As can be seen in Table 1, in the case of Comparative Examples 1 and 2 is less content of the heat stabilizer used, the pressure resistance is lowered, Comparative Example 3 lacks impact resistance, when using only ethylene block polypropylene as in Comparative Example 4 In spite of the use of a sufficient amount of heat stabilizer, the impact resistance is excellent but the pressure resistance is lowered. In addition, in the case of Comparative Example 5, the pressure resistance is insufficient and the impact strength is insufficient, in the case of Comparative Example 6, the heat resistance stabilizer content is low, the pressure resistance is lowered.

However, as can be seen from the physical property measurement results for Examples 1 and 2, it can be seen that the polypropylene resin composition according to the present invention shows excellent results in terms of pressure resistance, impact resistance and processability.

The polypropylene resin composition of the present invention is improved in pressure resistance, impact resistance and processability, and can be applied to a pipe, a hot water pipe device, a pipe fitting, and the like.

Claims (2)

(i) ethylene random polypropylene having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 0.1 to 10 mol% and an ethylene block polypropylene having a melt index of 0.1 to 10 g / 10 minutes and an ethylene content of 1 to 20 mol%. Polypropylene resin 69.45-99.7 wt%; (ii) 0.1 to 30 weight percent PP plastomer and (iii) A polypropylene resin composition for pipes and hot water pipe devices, comprising 0.2 to 0.55 wt% of a heat stabilizer. The heat stabilizer according to claim 1, wherein the heat stabilizer is 3,3 ', 3', 5,5 ', 5'-nucleated-tert-butyl-a, a', a '-(mesitylene-2,4,6-tri (I) a tri-p-cresol. Polypropylene resin composition for pipes and hot water pipe apparatuses.