KR910003589B1 - Preparation for polyester copolymer - Google Patents

Abstract

The polyester block copolymer is prepd. by addition and copolymerization of the soft segment component comprising the aliphatic polyester diol of formula (I) and aromatic dicarboxylic acid, and the hard segment component comprising the lower molecular weight diol and aromatic dicarboxylic acid. In the formula, R1 is methyl or ethyl; R2 is H, methyl or ethyl; X is integer of 1-10; n is integer of 1-30. The obtd. copolymer has a good heat resistance and elasticity by using the aliphatic polyester diol in place of polyeter in soft segment part.

Description

Manufacturing method of polyester block copolymer having excellent heat resistance and elasticity

The present invention relates to a method for producing a polyester block copolymer having excellent thermal oxidation resistance and elasticity. A polyester polyether block copolymer having a polyester portion and a polyether portion alternately in a molecular chain is a thermoplastic resin having a high elasticity in rubber because the polyester portion is bonded as a hard segment and the polyether portions as a soft segment. Known.

The hard segment of the thermoplastic copolyether ester is formed by esterification of dicarboxylic acid with low molecular weight diol, and the soft segment is formed by reaction of dicarboxylic acid with polyether glycol.

Here, as the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 1.5-naphthalenedicarboxylic acid, 2.6-naphthalenedicarboxylic acid, etc. are used, and as the low molecular weight diol component, ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexa Methylene glycol, 2.2-dimethyltrimethylene glycol, and the like are used, and polyether glycol components include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

These copolyetherester polymers are applied to hoses, belts, tubes, som gears, wheel parts, and sporting goods by using their high elasticity, but are deteriorated due to the action of oxygen, heat and ozone in the air. Cracks are formed on the surface, and elasticity decreases due to stretching, resulting in a decrease in polymerization degree and a significant decrease in mechanical properties. Therefore, in order to prevent such deterioration, various special stabilizers are added in Japanese Unexamined Patent Publication No. 46-42025 and US Patent No. 4,136,090. In addition, various problems such as discoloration due to the addition of stabilizers are exposed.

On the other hand, in order to improve the elasticity of the copolymer, a method by adding a special additive is conventionally disclosed in Japanese Patent Laid-Open No. 48-55235, and a method of adding a crosslinking agent has been disclosed in US Pat. No. 4,349,469. These methods have the problem of increasing the elasticity of the copolymer while causing other physical and mechanical properties to weaken.

The inventors have noted that polyester-polyether copolymers have ether portions that are susceptible to oxidation and result in reduced elasticity by crystallization of soft segments that impart rubber elasticity, and therefore use aliphatic polyester diols instead of polyethers in soft segments. Thus, the inventors have invented a polyester block copolymer that is stable to heat and excellent in elasticity.

Hereinafter, the present invention will be described in more detail.

The present invention is a method for producing a polyester block copolymer having excellent thermal stability and elasticity using an aromatic dicarboxylic acid and a low molecular weight diol as a hard segment and an aromatic dicarboxylic acid and an aliphatic polyester diol as a soft segment.

In the present invention, the aromatic dicarboxylic acid component is terephthalic acid, isophthalic acid, 1.5-naphthalenedicarboxylic acid, 2.6-naphthalenedicarboxylic acid and esters thereof and the like. The low molecular weight diol is ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexa Methylene glycol, 2.2-dimethyltrimethylene glycol and the like are used. Moreover, aliphatic polyester diol is a compound represented by general formula (I).

In the above formula, R ₁ is a methyl or ethyl group, R ₂ is a hydrogen or methyl or ethyl group, X is an integer of 1-10, n is an integer of 1-30. Specific examples thereof include polyneopentyl adipate diol, polyneopentyl sebagate diol, polyneopentyl-acylate diol, polyisopropyl adipate diol, polyisopropyl sebagate diol, and polyisopropyl azilate diol. The soft segment content in the polyester block polymer may be 5-85 parts based on 100 parts by weight of the polyester block polymer. Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

A mixture of 39 g of dimethylene terephthalate, 27 g of tetramethylene glycol, and 20 g of polyneopentyl-adipate diol (average molecular weight 850-1150) was placed in a polymerization vessel, and contacted with air was removed, followed by a catalyst (a mixture of magnesium diacetate and titanium tetrabutoxide). ) After adding 0.5g, the reaction is fixed at 200 ℃ under normal pressure and methanol is released. When the methanol outflow was almost stopped, the temperature was gradually raised to 250 ° C. to completely remove the remaining methanol, and then slowly depressurized and reacted under vacuum of 0.1 mmHg for 2 hours, followed by cooling in cold water. Physical properties of the synthesized copolymer are shown in Table (1).

Comparative Example 1

A mixture of 39 g of dimethylene terephthalate, 25 g of tetramethylene glycol and 41 g of polytetramethylene glycol (average molecular weight 1900-2100) was placed in a polymerization vessel, and nitrogen was blown to remove contact with air, followed by a catalyst (magnesium diacetate and titanium tetrabutoxide). 0.4 g of the mixture is added, and the reaction is carried out by fixing the temperature at 200 ° C. at atmospheric pressure to release methanol. When the methanol outflow was almost stopped, the temperature was gradually raised to 250 ° C. to completely remove the remaining methanol, and then slowly depressurized and reacted under vacuum of 0.1 mmHg for 2 hours, followed by cooling in cold water. Physical properties of the synthesized copolymer are shown in Table (1).

Example 2

A mixture of 33 g of dimethylene terephthalate, 5.8 g of dimethylphthalate, 25 g of tetramethylene glycol, and 41 g of polyneopentadiadiate diol (average molecular weight 850-1150) was placed in a polymerization vessel, and 0.4 g of a catalyst was added thereto. To synthesize. Physical properties of the synthesized copolymer are shown in Table (1).

Comparative Example 2

A mixture of 40 g of dimethylene terephthalate, 27 g of tetramethylene glycol, and 35 g of polycapurolactone diol (average molecular weight 2000) was placed in a polymerization vessel, 0.4g of a catalyst was synthesized in the same manner as in Comparative Example 1. Physical properties of the synthesized copolymer are shown in Table (1).

Example 3

A mixture of 42 g of dimethylene terephthalate, 0.2 g of trimellitic acid, 28 g of tetrakenylene glycol, and 34 g of polyneopentadiadiate diol (average molecular weight 850-1150) was placed in a polymerization vessel, and 0.4 g of a catalyst was added thereto. Synthesize in the same way. Physical properties of the synthesized copolymer are shown in Table (1).

TABLE 1

* Melting Point of Co-Medium: Measured by Differential Thermal Analyzer

Pyrolysis onset temperature: measured by thermogravimetric method

Elastic recovery rate: A film with a width of 1 cm, a length of 10 cm, and a thickness of 1 mm was made and obtained as the elastic recovery rate at 100% elongation.

Claims (1)

It is characterized by using an aliphatic polyester diol and an aromatic dicarboxylic acid represented by the general formula (I) as a soft segment component, and to the heat resistance to copolymerize by adding a low molecular weight diol and an aromatic dicarboxylic acid, which is a conventional hard segment component Method for producing a block copolymer having excellent elasticity.

Wherein R ₁ is a methyl or ethyl group, R ₂ is a hydrogen or methyl or ethyl group, X is an integer from 1-10 and n is an integer from 1-30.