JPS5922735B2 - Method for manufacturing polyester elastomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester elastomers.

More specifically, the present invention relates to a method for producing a polyester elastomer having excellent mechanical strength and weather resistance. Conventionally, natural rubber, vinyl-based synthetic rubber, polyurethane, and the like have been widely used as elastomers, but aromatic polyester-based elastomers have recently attracted attention because they have excellent bending fatigue resistance and low-temperature properties.

However, despite its excellent properties, such polyester elastomers have poor heat resistance and weather resistance, which limits their use. For example, its use as an engine gasket or for covering electric wires is restricted. The present inventors focused on this point and, as a result of intensive research, found that a polyester elastomer containing an aromatic dicarboxylic acid as an acid component was copolymerized with a specific amount of aliphatic dicarboxylic acid, and the heat resistance and The present invention has been achieved based on the discovery that weather resistance is improved, solubility in solvents is improved, and mechanical properties such as tensile strength and tear strength are surprisingly improved.

That is, the present invention provides dicarboxylic acids mainly including terephthalic acid and/or ester-forming derivatives thereof, (m low molecular weight glycols and/or ester-forming derivatives thereof,
and (C) when producing a polyester elastomer by reacting polyoxytetramethylene glycol and/or its ester-forming derivative having an average molecular weight of 500 to 5,000, the W component dicarboxylic acid and/or its ester-forming derivative is aliphatic. containing a dicarboxylic acid and/or an ester-forming derivative thereof, and having the following formula [wherein, M
is the average molecular weight of polyoxytetramethylene glycol,
W is the mol% of the aliphatic dicarboxylic acid and/or its ester-forming derivative in component (4).

This is a method for producing a polyester elastomer characterized by satisfying the following.

The dicarboxylic acid component (4) consists mainly of terephthalic acid and aliphatic dicarboxylic acid.

Examples of the aliphatic dicarboxylic acids include polymethylene dicarboxylic acids such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and decamethylene dicarboxylic acid; 2-methyladipic acid, 2-ethyl suberic acid, 2-ethyl suberic acid,
Examples include side chain aliphatic dicarboxylic acids such as 2,3,3-tetramethylsuccinic acid. Moreover, an aliphatic oxycarboxylic acid such as ε-oxycaproic acid can be used instead of the aliphatic dicarboxylic acid. Furthermore, similar to the aforementioned terephthalic acid and aliphatic dicarboxylic acid, ester-forming derivatives thereof can also be used.

Such ester-forming derivatives include lower alkyl esters such as methyl ester, ethyl ester, etc.;
Substituted aliphatic esters such as hydroxybutyl esters;
Examples include aryl esters such as phenyl esters; carbonic acid esters; acid halides, and preferred examples include dimethyl terephthalate, dimethyl decamethylene dicarboxylic acid, dimethyl sebacate, and ε-caprolactone. Among these, lower alkyl esters are particularly preferred. (4) The main components are terephthalic acid and/or its ester-forming derivatives and aliphatic dicarboxylic acids and/or its ester-forming derivatives, but up to 15 mol% of the total acid components are other dicarboxylic acids and / or an ester-forming derivative thereof.

Examples of the other dicarboxylic acids include aromatic acids other than terephthalic acid such as isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl-4,4' dicarboxylic acid, and 4,4 diphenoxyethane dicarboxylic acid. Dicarboxylic acid; 1,4-diclohexanedicarboxylic acid, 4,4
'-Methylenebis-(cyclohexyl)carbonyl 77
Examples include oxycarboxylic acids such as i′,″.′.7τroundwork≦:.

Examples of other ester-forming derivatives of dicarboxylic acids include dimethyl isophthalate, dimethyl 2,6-naphthalene dicarboxylate, and ethyl P-(β-oxyethoxy)benzoate. In the present invention, the aliphatic dicarboxylic acid and/or
or its ester-forming derivative has the formula (in the above formula, M
is the average molecular weight of polyoxytetramethylene glycol, W
is the mol% of the aliphatic dicarboxylic acid and/or its ester-forming derivative in component (4).

) must be used to satisfy the requirements.

Although the reason is not clear when the mole percent of the aliphatic dicarboxylic acid and/or its ester-forming derivative in component (4) satisfies the above formula, the resulting elastomer is It shows little decrease in tensile strength even when exposed to high temperatures or after accelerated weathering tests, has excellent heat resistance and weather resistance, and has good solubility in solvents, making it suitable for molding by dipping. Furthermore, it has excellent mechanical properties such as tensile strength and tear strength. If W in the above formula is smaller than the left side, the tensile strength and tear strength among the above-mentioned excellent physical properties will decrease, and if it is larger than the right side, the heat resistance will deteriorate, which is not preferable. Examples of the low molecular weight glycol used as the component (8) include aliphatic glycols such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, and neopentyl glycol; 1,1-cyclohexanedimethanol, 1,
Aliphatic glycols such as 4-cyclohexanedimethanol; 2,2'-bis[4-(2-oxyethoxy)phenyl]propane, bis[4-(2-oxyethoxy)
Aromatic glycols such as phenyl]sulfone and the like can be mentioned. Among these, aliphatic glycols are preferred. Even if only one type of low molecular weight glycol is used,
Moreover, two or more types may be used. Further, the low molecular weight glycol preferably has a molecular weight of 400 or less. Similar to the above-mentioned low molecular weight glycols, ester-forming derivatives thereof can also be used.

Examples of such ester-forming derivatives include monoesters and diesters with monocarboxylic acids. As the monocarboxylic acid, aliphatic monocarboxylic acids (eg, acetic acid, propionic acid, butyric acid, etc.) are preferred. The average molecular weight of the component (C) is 500 to 5000, preferably 1000.
~2000 polyoxytetramethylene glycol is used.

The average molecular weight of the polyoxyalkylene glycol is 50
If the average molecular weight is less than 0, the resulting polyester will have insufficient elasticity, and if the average molecular weight is more than 5,000, it will be difficult to copolymerize into the polyester and will tend to become a mere blend, which is not preferred. Similar to the polyoxytetramethylene glycol described above, its ester-forming derivatives can also be used.

Examples of such ester-forming derivatives include monoesters and diesters with monocarboxylic acids. Component (C) is preferably used so that its polyoxytetramethylene component accounts for 30 to 65% by weight of the polyester elastomer produced.

The polyoxytetramethylene component referred to herein refers to a polyoxytetramethylene moiety composed only of repeating units of the polyoxytetramethylene glycol or its ester-forming derivative. In the present invention, in addition to the above three components, trifunctional or higher functional ester-forming monomers such as pentaerythritol, trimellitic acid, etc. may be used in an amount of up to 1 mol % based on the dicarboxylic acid.

In the present invention, a preferred method for producing a polyester elastomer by reacting the three components is to react a lower alkyl ester of dicarboxylic acid with polyoxytetramethylene glycol and an excess of low molecular weight glycol in the presence of a catalyst at 160 to 240°C. At the same time, methanol produced by the transesterification reaction is distilled off to form a low polymer, and this low polymer is further heated under high vacuum at 220 °C.
Polycondensation was carried out by heating and stirring at a temperature of ~260°C and distilling off excess glycol, resulting in polyester Eral 58.2
8 parts, 0.17 parts of pentaerythritol, and 0.085 parts of tetrabutyl titanate, and heated to 170-220°C.
The methanol produced by heating was distilled out of the system. After the methanol distillation was almost completed, the reaction product was transferred to a polymerization vessel equipped with a stirrer and reacted at normal pressure for 30 minutes at a temperature of 240°C.
Next, the reaction was carried out for 30 minutes under a weak vacuum of about 20% Hg, and further for 3 hours under a high vacuum of 0.1 to 0.311 Hg. Next, as a stabilization system, 1.66 parts of IrganOxlO35 (manufactured by Ciba-Geigi Co., Ltd.) and Tinuvin327 (
0.10 part of Ciba-Geigi Co., Ltd.) was added thereto, and the mixture was further stirred for 15 minutes under high vacuum. The reduced viscosity and softening point of the obtained polyester elastomer are as shown in Table 1. This polyester elastomer was chipped, and after drying, a tampel-type sample (according to JIS K63Ol) was prepared using an injection molding machine, and surface hardness, tensile strength, tear strength, weather resistance, and heat resistance were measured. The results are shown in Table 1.
This polyester elastomer chip is molded into a thread with a diameter of 11 mm and a length of 1 C! It was cut into RL and its solubility in the drug was examined. The results are shown in Table 1. Example
2 87.39 parts of terephthalic acid dimethyl ester, 12.92 parts of decamethylene dicarboxylic acid dimethyl ester (10 mol % based on the total acid components), 90.12 parts of tetramethylene glycol, polyoxytetramethylene glycol with an average molecular weight of 1500 59 .1 part pentaesritol 0.
17 parts, tetrabutyl titanate 0.085 parts, Irg
1,69 parts of anOxlO35 (manufactured by Ciba Geigi Co., Ltd.) and 0.10 parts of Tinuvin327 (manufactured by f-Bagaigi Co., Ltd.)
A polyester elastomer was produced in the same manner as in Example 1.

The reduced viscosity, softening point, surface hardness, tensile strength, tear strength, weather resistance, heat resistance, and solubility in solvents of the obtained polyester elastomer were measured. The results are shown in Table 1.

Comparative Example 1 97.10 parts of dimethyl terephthalate, 90.12 parts of tetramethylene glycol, 85.88 parts of polyoxytetramethylene glycol with an average molecular weight of 1500, 0.19 parts of pentaerythritol, 0.085 parts of tetrabutyl titanate, IrganOxlO35 ( A polyester elastomer was produced in the same manner as in Example 1 using 1.91 parts of Tinuvin 327 (manufactured by Ciba-Geigi Co., Ltd.) and 0.11 parts of Tinuvin 327 (manufactured by Ciba-Geigi Co., Ltd.).

The reduced viscosity, softening point, surface hardness, tensile strength, tear strength, weather resistance, heat resistance, and solubility in solvents of the obtained polyester elastomer were measured. The results are shown in Table 1.

In Table 1, the surface hardness is the value according to Shore (9), the tensile strength and tear strength are the values according to JISK63Ol, and the weather resistance is measured using a tampel-type sample with a standard xenon weather meter (manufactured by Toho Rika Kogyo). So 12
Retention rate of tensile strength after irradiation for days (value expressed in degrees,
Heat resistance is a value expressed as tensile strength retention (%) after exposing a tampel-type sample to hot air at 140°C for 14 days.
(This is the value expressed in n, the time required for complete dissolution, such as when placed in Jl. and stirred under heating and reflux.

Example 3 5, 6, 7, 8 parts of dimethyl terephthalate, 11.17 parts (15 mol%) of dimethyl azelaate, tetramethylene glycol JMoV. 5 parts, 1000 parts of polyoxytetramethylene glycol with an average molecular weight of 2000, 0.14 parts of pentaerythritol, 2.00 parts of RganOxlO35 (manufactured by Ciba-Geigi Co., Ltd.), and 0.10 parts of Tinuvin327 (manufactured by Chiba-Geigi Co., Ltd.). A polyester elastomer having a reduced viscosity and softening point as shown in Table 2 was obtained in the same manner as in Example 1, except that the vacuum reaction was carried out for 4 hours.

Table 2 shows the values obtained by molding and measuring in the same manner as in Example 1. Comparative Example 2 66.8 parts of dimethyl terephthalate, tetramethylene glycol JMoV. 5 parts, 130.0 parts of polyoxytetramethylene glycol with an average molecular weight of 2000, 0.14 parts of pentaerythritol, 0 parts of tetrabutyl titanate
．． A polyester elastomer was obtained in the same manner as in Example 1, except that 085 parts of RganOxlO35 (manufactured by Ciba Geigi Co., Ltd.), 2.00 parts of Tinuvin 327 (manufactured by Ciba Geigi Co., Ltd.) and 0.10 parts of Tinuvin 327 (manufactured by Ciba Geigi Co., Ltd.) were used, and the high vacuum reaction was carried out for 4 hours. It was molded in the same manner as in Example 1.

The results are shown in Table 2. In addition, in Table 2, the weather resistance is the value for the same measurement as in Table 1, except that the weather resistance was changed after 4 days of irradiation with a standard xenon weather meter, and the heat resistance was changed after 14 days of exposure in hot air at 120 ° C. .

Claims (1)

[Scope of Claims] 1 (A) dicarboxylic acid mainly consisting of terephthalic acid and/or
or an ester-forming derivative thereof (B) a low molecular weight glycol and/or an ester-forming derivative thereof, and (C)
When producing a polyester elastomer by reacting polyoxytetramethylene glycol and/or its ester-forming derivative having an average molecular weight of 500 to 5,000, the component (A) dicarboxylic acid and/or its ester-forming derivative is an aliphatic dicarboxylic acid. and/or an ester-forming derivative thereof, and has the following formula M-300/500
≦W≦M+5500/375 [wherein, M is the average molecular weight of polyoxytetramethylene glycol, and W is (A)
It is the mole percent of the aliphatic dicarboxylic acid and/or its ester-forming derivative in the component. ], and the component (C) is 30% of the produced polyester.
A method for producing a polyester elastomer, characterized in that it accounts for ~65% by weight.