KR940011409B1 - Polypropylene copolymer resin composition for plastic pipe for heating - Google Patents

Abstract

The polypropylene copolymer resin composition for a hot water heating plastic pipe is composed of 70-98 wt.% of propylene-ethylene copolymer havign 1-30 % ethylene content, 1-10 wt.% of propylene-butylene copolymer having 1-30 % butylene content, 1-30 wt.% of propylene polymer, and additives of at most 5 wt.% of antioxidant, at most 5 wt.% of acid acceptor i.e. calcium stearate (or zinc peroxide) and at most 5 wt.% of ultraviolet stabilizer. The resin compsn. is used as a molding material of a heating pipe having a good durability and transparency.

Description

Polypropylene copolymer resin composition for heating plastic pipe

The present invention relates to a blending composition comprising a copolymer of a propylene polymer and a propylene-αolefin, which is a pipe forming material for heating having excellent durability and transparency.

The plastic pipe forming materials for heating used so far are polyvinyl chloride, crosslinked polyethylene, polypropylene copolymer and the like.

The polyvinyl chloride has the disadvantage that the pipe can be ruptured at low temperature, the process is complicated in construction and the pipe life at high temperature is not long.

On the other hand, the crosslinked polyethylene is difficult to solve the problem of poor workability due to the connection problem of plastic pipes because of the difficulty of production due to the control of the degree of crosslinking during molding and the thermal fusion during construction.

In addition, since the conventionally used polypropylene copolymer does not have the characteristics of a pipe alone by the copolymer of propylene and ethylene, ethylene-propylene elastomers (EPR, EPDM) must be melt-mixed, and productivity and economical efficiency are reduced due to melt mixing. Was the problem.

Accordingly, the present inventors have proposed a molding material made of a propylene block copolymer obtained by sequentially polymerizing propylene, ethylene, and butylene in a reactor.

In the present invention, a composition having a pipe performance can be obtained by blending the composition described below in addition to the method proposed above. More specifically, propylene-ethylene copolymer containing propylene-ethylene copolymer containing 1-30% ethylene, propylene-butylene copolymer containing 1-30% butylene and propylene homopolymer 2 A composition blended with two or more resins.

A catalyst and a promoter are used in the reactor to produce each resin polymer and polymerized at a reaction temperature of 50-150 ° C. and a reaction pressure of 10-50 Kg / cm 2. At this time, the catalyst is preferably titanium tetrachloride supported on magnesium chloride, and as an organic aluminum compound, triethyl aluminum (TEAL), diethyl aluminum chlorate (DEAC), and the like are preferable.

The polymer produced in each polymerization process is melt-mixed and extruded with a mixer, a single screw extruder, a twin screw extruder, etc. At this time, the extrusion temperature range is 180-250 ° C, and the rpm is 60-180. Antioxidants, acid acceptors, and / or UV stabilizers may be used as additives used in melt mixing.

As antioxidants, for example, phenolic antioxidants, phosphite antioxidants, thiodipropinoenite synergists and the like are used, and as acid acceptors, for example, calcium stearate and zinc peroxide are used.

0.01-5% by weight of antioxidant, 0.01-5% by weight of acid acceptor and 3% by weight or less of UV stabilizer are preferable. In blending, the composition of each resin is 70-99% of the propylene-ethylene copolymer, 0-30% of the propylene-butylene copolymer resin, and 0-30% of the propylene homopolymer resin. The specific gravity of each resin is 0.90-0.93, and MI is in the range of 0.1-3.

All the pipes manufactured in the present invention were subjected to the PP-C pipe performance test based on KS M-3362. As a result, all the pipes manufactured by the above method passed the performance test. Specific matters are described in the following examples.

Example 1

A titanium tetrachloride catalyst and a triethylammonium promoter supported on magnesium chloride were charged into a 5 l autoclave, and 96 parts by weight of propylene and ethylene were made into 4 parts by weight of copolymerized resin (a), propylene and butylene, 98 parts by weight. Parts and 2 parts by weight of the copolymerized resin (b) propylene homopolymer resin (c) three resins and additives are melt-mixed in the following composition and injected into a barrel at 200 ° C. The barrel temperature was 210/230/240/220/220 and the rpm was 150 to form molding particles. The composition of the resin used at this time is as follows.

Propylene-ethylene copolymer resin 92.0%

Propylene butylene copolymer resin 1.5%

Propylene Homopolymer 5.0%

Small amount of phenolic antioxidant

Small amount of zinc peroxide

Thiodipropionate Synergy

Example 2

Molding particles were prepared in the same manner as in Example 1 with the resin compositions shown.

Propylene-ethylene copolymer resin 96.0%

Propylene butylene copolymer resin 3.5%

Small amount of phenolic antioxidant resin

Small amount of zinc peroxide

Thiodipropionate Synergy

Example 3

In preparing the propylene-ethylene copolymer in the same reactor as in Example 1, the content of ethylene was 6 parts by weight, the content of butylene was 3 parts by weight, and the content of butylene was 3 parts by weight. The composition of each resin was changed as follows, blended, and extruded with a twin screw extruder. The reaction conditions are the same as in Example 1.

Propylene-ethylene Copolymer 88.0%

Propylene-Butylene Copolymer 3.0%

Propylene Homopolymer 8.5%

Small amount of phenolic antioxidant

Small amount of calcium stearate

Thiodipropionate Synergy

The pipe made of the resin polymerized in Example 1-3 passed the 1 hour break pressure creep test carried out at 20 ° C. and 16 N / mm 2, and the 1,000 Hr was carried out at 95 ° C. and 1.9 N / mm 2. The pressure resistant creep test also passed. This performance represents 50 years of durability at 65 ° C. In addition, it passed both the low temperature impact strength test and the high temperature numerical stability test performed at 0 degreeC. Thus, this invention can obtain the resin composition for heating plastic pipes with long pipe life, excellent workability, and transparency, without degrading productivity and economy.

Claims (6)

(a) 70-98% by weight propylene-ethylene copolymer having an ethylene content of 1-30%, (b) 1-10% by weight of butylene content having a 1-30% propylene-butylene copolymer, and (c) propylene Resin composition for heating plastic pipes containing 1-30 weight% of homopolymer parts. Heating plastic comprising (a) 70-99% by weight propylene-ethylene copolymer with 1-30% ethylene content, and (b) 1-30% by weight propylene-butylene copolymer with 1-30% butylene content Resin composition for pipes. A composition for pipe molding of poor heating plastics having an additive of 13% or less in the resin composition of claim 1. The composition for forming a heated plastic pipe according to claim 1, wherein the additive is 5 wt% or less of an antioxidant, 5 wt%, an acid acceptor, and 3 wt% or less of an ultraviolet stabilizer based on the resin composition. A composition for molding a poor heating plastic pipe comprising up to 13% of an additive in the resin composition of claim 2. The heating plastic pipe molding composition according to claim 2, wherein the additive is 5 wt% or less of an antioxidant, 5 wt% or less of an acidic solvent, and 3 wt% or less of an ultraviolet stabilizer based on the resin composition.