JPS624721A - Production of polyester elastomer - Google Patents

Abstract

PURPOSE:To obtain the titled elastomer excellent in strength, weathering resistance, etc., by adding an aliphatic long-chain glycol to the raw material in the production of a polyester by reacting a terephthalic acid-based dicarboxylic acid with a low-MW glycol. CONSTITUTION:The titled elastomer is obtained by reacting a terephthalic acid-based dicarboxylic acid (esterifiable derivative) (A) (e.g., dimethyl terephthalate) with a low-MW glycol (esterifiable derivative) (B) (e.g., ethylene glycol) and an aliphatic long-chain glycol (esterifiable derivative) (C) of an average MW of about 350-6,000 (e.g., hydrogenated liquid polybutadiene glycol) at such a ratio that 65-97wt% of the formed polymer consists of a short-chain ester segment which is the reaction product between components A and B and the balance consists of a long-chain ester segment which is the reaction product between components A and C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing a polyester elastomer. More specifically, the present invention relates to a method for producing a polyester elastomer having excellent mechanical strength and weather resistance.

(Prior art and problems to be solved by the invention) Conventionally, natural rubber, synthetic rubber, polyurethane, etc. have been widely used as elastomers (but they have poor mechanical properties and heat resistance, and have poor mechanical properties at high temperatures. There is a problem.Recently,
Aromatic polyester elastomers are attracting attention because of their mechanical properties and heat resistance. However, conventional polyester elastomers mainly contain polytetramethylene glycol or polycaprolactone in their long chain ester segments, and have poor heat resistance, heat aging resistance, and moisture resistance, which limits their use in outdoor applications. It was.

(Means for solving the problem) The present inventors focused on this point, and as a result of intensive research, 2 polyester elastomers do not contain oxygen atoms in the main chain of the molecule except for the terminal pipe group in the long chain ester segment. The present invention was achieved by discovering that by using an aliphatic long-chain glycol, the resulting polyester elastomer has improved heat resistance, weather resistance, and moisture resistance, and also has excellent mechanical properties.

That is, the present invention provides: (A) a dicarboxylic acid mainly consisting of terephthalic acid and/or an ester-forming derivative thereof; (
B) When producing a polyester elastomer by reacting a low molecular weight glycol and/or an ester-forming derivative thereof and (C) an aliphatic long-chain glycol having an average molecular weight of about 350 to 6,000 and/or an ester-forming derivative thereof, 65 ~97% by weight is (A) and (B
) is used in a proportion such that short chain ester segments are formed as a reaction product of polyester elastomer.

(Function) The polyester elastomer according to the present invention substantially consists of a short chain ester segment and a long chain ester segment, and the short chain ester segment consists of a dicarboxylic acid as the component (A) and a low molecular weight glycol as the component (B). (A>
The main component is terephthalic acid and/or its ester-forming derivative, but the amount is 30 mol% based on the total acid component.
may contain other dicarboxylic acids and/or ester-forming derivatives thereof.

Examples of the dicarboxylic acids mentioned above include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, and 2,6-naphthalene dicarboxylic acid, oxycarboxylic acids such as p-oxybenzoic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid. ,
Straight chain saturated aliphatic dicarboxylic acids having 4 to 20 carbon atoms such as decamethylene dicarboxylic acid and octadecane dicarboxylic acid;
2-methyladipic acid, 2-ethylsperic acid, 2,
Examples include side-chain aliphatic dicarboxylic acids such as 2,3.3-tetramethylsuccinic acid, aliphatic oxycarboxylic acids such as ε-oxycaproic acid, and dimer acids. (
Component B) is a low molecular weight glycol and/or an ester-forming derivative thereof, such as ethylene glycol, trimethylene glycol, 1,4-butanediol, 1.
Aliphatic glycols such as 5-bentanediol, 1゜6-hexanediol, neopentyl glycol, 1.4-
Examples include alicyclic glycols such as cyclohexane dimetatool, among which ethylene glycol and 1,4-butanediol are preferred. The 2° long-chain ester segment, which can be used alone or in combination of two or more low molecular weight glycols, is the component (A) component dicarboxylic acid and (
C) Consists of component aliphatic long chain glycol. Component (C) is an aliphatic long chain glycol with an average molecular weight of about 350 to 6,000 and/or an ester-forming derivative thereof, 9 such as 1,2-polybutadiene glycol, 1,4-polybutadiene glycol, or a combination thereof. Polymers or mixtures thereof, hydrogenated products thereof, polyolefin glycols, etc. are preferably used. When polybutadiene is used, hydrogenated polybutadiene whose double bonds are hydrogenated is preferred because it is stable during polymerization. The average molecular weight of component (C) is approximately 350 to 6000. Preferably 800-3000.
More preferably, it is 1000-2500. If the molecular weight is less than 350, the elasticity of the polyester will be insufficient, and if the molecular weight is more than 6,000, it will be difficult to copolymerize as a polyester.

The polyester copolymer of the present invention contains 65 to 97% by weight, preferably 75 to 95% by weight of short chain ester segments.
More preferably, it contains 80 to 95% by weight, with the remainder being long chain ester segments. 65 short chain ester segments
Polyester copolymers containing less than 97% by weight of short chain segments have a lower initial modulus and reduced resistance to aging by solvents and heat, and polyester copolymers containing more than 97% by weight of short chain segments have less elasticity.
It has poor low temperature properties and no longer exhibits elastomer properties.

The melting point of the polyester elastomer in the present invention is 15
The temperature is preferably 0°C or higher. If the temperature is less than 150°C, the heat deformation temperature will become low, causing problems and making it difficult to put it to practical use as a molded product.

In the present invention, in addition to the above-mentioned three components, tri- or higher-functional ester-forming monomers such as trimethylolpropane, pentaerythritol, trimellitic acid, etc. can be used depending on the case. In the present invention, a preferred method for producing a polyester elastomer by reacting the above three components is to react a lower alkyl ester of a dicarboxylic acid with an aliphatic long chain glycol and an excess low molecular weight glycol in the presence of a catalyst at a temperature of 160 to 240°C. The mixture is heated to perform a transesterification reaction to first form a low polymer, and then this low polymer is heated and stirred at a temperature of 220 to 280°C under high vacuum.
This method involves polycondensation to produce a polyester elastomer.

The low polymers can also be obtained by direct esterification reaction of dicarboxylic acids with aliphatic long chain glycols and low molecular weight glycols. Furthermore, after performing a transesterification reaction using a part of the dicarboxylic acid in the form of an alkyl ester,
The remaining dicarboxylic acid may be added to carry out the esterification reaction. Also.

Obtained by transesterification reaction or esterification reaction,
A polyester elastomer can also be obtained by subjecting a low polymer of a dicarboxylic acid component and a low molecular weight glycol component to a five-poly condensation reaction with an aliphatic long-chain glycol.

Furthermore, a low polymer of a part of the dicarboxylic acid component and an aliphatic long chain glycol is prepared in advance, and the remaining dicarboxylic acid component and low molecular weight glycol are added thereto, followed by transesterification or esterification reaction, followed by polycondensation. Polyester elastomers can also be obtained. Any of the various catalysts known during these polymerization or transesterification reactions.

Stabilizers may also be used.

In the present invention, various stabilizers such as oxidation stabilizers, heat stabilizers, and light stabilizers, R materials, glass fibers, and other reinforcing agents,
Various additives such as carbon black, alumina, silica gel, clay, etc. can be added as necessary.

(Example) The present invention will be explained in more detail below using two examples.

Note that "parts" in the examples mean "parts by weight." Further, the characteristic values in the examples were measured by the following method.

(2) Intrinsic viscosity Measured at 20°C in a mixed solvent of phenol:tetrachloroethane=1:1 (weight ratio).

■Melting point (°C) Using PerkinElmer DSCZC type, 20°C/
The temperature was increased in minutes and the melting peak temperature was measured.

■Surface hardness Value is Shore D according to JIS K-6301.

■Tensile strength (Kg/e11!) According to JIS K~6301.

(2) Weather resistance and moisture resistance This value is expressed as the retention rate (%) of tensile strength after irradiating a dumbbell-shaped sample with a sunshine weather meter for 200 hours.

(2) Heat Aging Resistance This value is expressed as the retention rate (%) of tensile strength after exposing a dumbbell-shaped sample to a hot air constant temperature bath at 140° C. for 300 hours.

Example 1 117 parts of dimethyl terephthalate, 73 parts of 1,4-bucundiol, average molecular weight of about 1. '300 hydrogenated liquid polybutadiene glycol (GI4000 manufactured by Nippon Soda Co., Ltd.
) 31 parts and 0.082 parts of tetra-n-butyl titanate
The mixture was heated to 200°C, and the generated methanol was distilled out of the system to carry out a transesterification reaction. After the methanol distillation was almost completed, the reaction product was transferred to a polymerization vessel equipped with a stirrer, and the vacuum was gradually lowered over 30 minutes at a temperature of 240°C to a high vacuum of 0.1 to 0.3 mm and 11 g. The polycondensation reaction was carried out for 4 hours.

The short chain ester segment of the obtained polyester elastomer was 79% by weight, and the intrinsic viscosity and melting point were as shown in Table 1. This polyester elastomer was made into chi-nobu, and after drying, a dumbbell-shaped sample (
(according to JIS K-6301) was prepared and its surface hardness, tensile strength, weather resistance, moisture resistance, and heat aging resistance were measured. The results are shown in Table 1.

Example 2 104 parts of dimethyl terephthalate, 14 parts of decamethylene dicarboxylic acid dimethyl ester (10 mol % based on the total acid components), 71 parts of L4-butanediol, average molecular weight of about 1
, 300 hydrogenated liquid polybutadiene glycol (
Nippon Soda Co., Ltd. G1-1000) 31 parts and Tetler. −
A polyester elastomer was produced in the same manner as in Example 1 by adding 0.081 part of butyl titanate. The resulting polyester elastomer had a short chain ester segment of 79% by weight and an intrinsic viscosity.

Melting point 1 Surface hardness, tensile strength, weather resistance, moisture resistance, and heat aging resistance were measured. The results are shown in Table 1.

Comparative Example 1 Using 121 parts of dimethyl terephthalate, 76 parts of 1,4-butanediol, 25 parts of polyoxytetramethylene glycol having an average molecular weight of about 1,000, and 0.085 parts of tetra-n-butyl titanate), the same procedure as that of Example 1 was carried out. A polyester elastomer was produced in the same manner. The resulting polyester elastomer had a short chain ester segment of 82% by weight, and its intrinsic viscosity, melting point 1 surface hardness, tensile strength, Wf+ weather, moisture resistance, and heat aging resistance were measured. The results are shown in Table 1.

Example 3 102 parts of dimethyl terephthalate, 26 parts of dimer acid (Empol 1010 manufactured by Emery, USA) (8 mol % based on the total acid components), and 70 parts of 1.4-butanediol.

Hydrogenated liquid polybutadiene glycol with an average molecular weight of about 1.300 (Gl-1000 manufactured by Nippon Soda Co., Ltd.) 22
part and 0.078 part of tetra-n-butyl titanate.

A polyester elastomer was produced in the same manner as in Example 1. The resulting polyester elastomer has short chain ester segments of 85% by weight, intrinsic viscosity, melting point 1, surface hardness, tensile strength, weather resistance, and moisture resistance.

Heat aging resistance was measured. The results are shown in Table 1.

Table 1 Example 4 108 parts of dimethyl terephthalate, 67 parts of 1,4-butanediol, and 0.038 parts of tetra-n-butyl titanate.
of the mixture was added as a catalyst and heated at 200° C. for 1 hour under a nitrogen atmosphere to carry out a transesterification reaction.

Next, hydrogenated liquid polybutadiene glycol having an average molecular weight of about 2.000 (Gl-2000 manufactured by Nippon Soda Co., Ltd.) 4
4 parts and 0.038 parts of tetra-n-butyl titanium) were added thereto, and the mixture was brought to a high vacuum of 30.1 to 0.3 mm and 11 g while gradually lowering the degree of vacuum at a temperature of 240° C. for 30 minutes.

Thereafter, a polycondensation reaction was carried out for 4 hours. The short chain ester segment of the resulting polyester elastomer was 71% by weight.
So, the intrinsic viscosity is 0.75. The melting point was 212°C. This polyester elastomer is made into chips.

After drying, a dumbbell-shaped sample (JIS
(according to K-6301) and has a surface hardness of 59° and a tensile strength of 352.3 Kg/cn! , weather resistance, moisture resistance 82
%, and heat aging resistance was 89%.

Comparative Example 2 Using 97 parts of dimethyl terephthalate, 64 parts of 1,4-butanediol, 61 parts of hydrogenated liquid polybutadiene glycol having an average molecular weight of about 2000, and 0.068 parts of tetra-n-butyl titanate, the same procedure as that of Example 4 was carried out. A polyester elastomer was produced in the same manner. The resulting polyester elastomer contains 60% by weight of short chain ester segments.
The intrinsic viscosity was 0.77 and the melting point was 204°C. The surface hardness of this polyester elastomer molded product is 55. Tensile strength 308.1 Kg/cflt, weather resistance.

The moisture resistance was 82% and the heat aging resistance was 88%.

(Effects of the Invention) The polyester elastomer obtained by the production method of the present invention has superior mechanical strength, weather resistance, moisture resistance, and heat aging resistance compared to conventionally known polyester elastomers. It is particularly effective for molded articles for use outdoors or in heated atmospheres. It can also be used as an adhesive having these characteristics, especially as a true melt adhesive or a sealant.

Claims (1)

[Claims] (1) (A) dicarboxylic acid mainly consisting of terephthalic acid and/or its ester-forming derivative, (B) low molecular weight glycol and/or its ester-forming derivative, and (C
) When producing a polyester elastomer by reacting an aliphatic long chain glycol with an average molecular weight of about 350 to 6,000 and/or its ester-forming derivative, 65 to 97% by weight of the polymer is a reaction product of (A) and (B). A method for producing a polyester elastomer, characterized in that it is used in such a proportion that it is formed of short chain ester segments.