JPH10130377A - Polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new polymer excellent in hydrolytic resistance, having no crystallization tendency, improved in handleability, containing a specific repeating unit comprising 3-methylpentanedicarboxylic acid or its alkyl ester as a dicarnboxylic acid component. SOLUTION: This polyester comprises >=20mol%, preferably >=60mol% of a repeating unit of the formula -CO-CH3 -CH(CH3 )-CH2 -CO-O-R (R is a 3-20C branched alkylene or a cycloalkylene which may contain a branched chain) and has 300-30,000, preferably 700-20,000 number-average molecular weight. The objective polymer is obtained by subjecting a dicarboxylic acid component essentially comprising 3-methylpentanedicarnoxylic acid or its alkyl ester and a diol component such as propylene glycol or cyclohexanedimethanol to polycondensatin by a known method. 3-Methylpentanedicarnboxylic acid is obtained, for example, by oxidizing 3-methyl-1,5-pentanediol with oxygen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to novel polyesters, and more particularly to polyesters suitable for applications such as paints, adhesives, polyurethanes and polyamide elastomers and polyester elastomers.

[0002]

2. Description of the Related Art In the field of paints, adhesives, polyurethanes and the like, polyesters having a hydroxyl group at the molecular terminal have been used. Such polyesters include ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6
Polyesters obtained from polyhydric alcohols such as hexanediol, trimethylolpropane and glycerin and polybasic acids or anhydrides or ester derivatives thereof are known. Among these polyesters, an aromatic dicarboxylic acid such as phthalic anhydride, isophthalic acid, and terephthalic acid is used in combination with an aliphatic dicarboxylic acid such as adipic acid as a polybasic acid, and a dihydric or trihydric or higher polyhydric alcohol and an ester are used. Hydroxyl-terminated polyesters obtained by the chemical reaction are widely used in the fields of paints and adhesives.

A hydroxyl-terminated polyester obtained by subjecting an aliphatic dicarboxylic acid such as adipic acid to an esterification reaction with a dihydric or trihydric or higher polyhydric alcohol is a 2-terminal polyester.
Polyurethane can be made by reacting with isocyanate compounds having functionalities or higher, and is used for a wide range of applications such as elastomers, paints, adhesives, coating agents, and foams. Furthermore, a polyester having a carboxyl group at the molecular end can be reacted with an isocyanate compound having two or more functionalities to obtain a polyester polyamide having excellent heat resistance.

[0004]

A conventional polyester having a hydroxyl group or a carboxyl group at a molecular terminal generally has poor hydrolysis resistance. For this reason, the products obtained from these conventional polyesters have a problem that the surface tends to become tacky or crack easily in a relatively short time.

In order to improve the hydrolysis resistance of the polyester, it is generally effective to reduce the ester group concentration of the polyester. In order to reduce the ester group concentration in the polyester, it is preferable to form the polyester from a diol having a large number of carbon atoms and a dicarboxylic acid having a large number of carbon atoms.However, the obtained polyester has a high tendency to crystallize and generally has a high viscosity liquid or There is a problem that it becomes solid and is inferior in workability. In addition, paints, adhesives, polyurethanes, and polyamide elastomers and polyester elastomers obtained from polyesters formed from a diol having a large number of carbon atoms and a dicarboxylic acid having a large number of carbon atoms have improved hydrolysis resistance, but are not crystallized. When left in a low-temperature atmosphere such as −20 ° C., for example, the low-temperature characteristics represented by bending resistance, flexibility (flexibility), low-temperature adhesion, and the like are significantly reduced.

The inventors of the present invention have conducted studies to provide a polyester having excellent hydrolysis resistance and no tendency to crystallize using industrially available raw materials. 8-octanediol and / or 1,9-
A polyester containing nonanediol has been found and a patent application has already been filed (see JP-A-63-182330). However, even with this polyester,
Some crystallization tendency may be observed at a temperature in a range usually used. Further, it is practically desirable to further improve the hydrolysis resistance of the polyester itself.

Thus, the present invention has excellent hydrolysis resistance,
A novel polyester which does not have a tendency to crystallize and provides a product having excellent hydrolysis resistance when used for applications such as paints, adhesives, polyurethanes, polyamide elastomers and polyester elastomers. That is the task.

[0008]

According to the present invention, in order to solve the problem] The problem is, the following equation _{(1) -CO-CH 2 -CH} (CH 3) -CH 2 -CO-O-R-O- ( 1) (wherein R represents at least one group selected from the group consisting of a branched alkylene group having 3 to 20 carbon atoms and a cycloalkylene group which may have a branch) And a number average molecular weight of 300 to 30,000.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyester of the present invention must contain at least 20 mol% of a repeating unit represented by the formula (1). If the content of the repeating unit represented by the formula (1) in the polyester is less than 20 mol%, the obtained polyester will have a high tendency to crystallize and will have poor physical properties such as hydrolysis resistance. The content of the repeating unit represented by the formula (1) in the polyester is preferably at least 40 mol%, more preferably at least 60 mol%.

In the above formula (1), examples of the branched alkylene group having 3 to 20 carbon atoms represented by R include propylene, 2-methyltetramethylene, 2-isopropyltetramethylene, 2-methylpentamethylene group, 2-methyloctamethylene group, 2,7
-Dimethyloctamethylene group, 2-methylnonamethylene group and the like. The branches in these alkylene groups preferably have 1 to 4 carbon atoms. Examples of the optionally branched cycloalkylene group represented by R include a 1,4-cyclohexylene group.

The repeating unit represented by the formula (1) is composed of a dicarboxylic acid unit represented by the following formula (2) and a diol unit represented by the following formula (3). —CO—CH ₂ —CH (CH ₃ ) —CH ₂ —CO— (2) —O—R—O— (3) (where R is as defined above) Here, the formula (2) The dicarboxylic acid unit represented by is derived from 3-methylpentanedioic acid or an alkyl ester of 3-methylpentanedioic acid. 3-Methylpentanedioic acid is, for example, 3-methyl-1,5-pentanediol, β-methyl-δ-valerolactone or 2-hydroxy-4-methyltetrahydropyran which is mass-produced and easily available. It can be industrially produced by oxygen oxidation. The alkyl ester of 3-methylpentanedioic acid can be obtained, for example, by esterifying 3-methylpentanedioic acid. Thus, any of the compounds can be industrially manufactured at low cost.

The polyester provided by the present invention is:
Other polycarboxylic acid units can be contained in addition to the dicarboxylic acid unit represented by the formula (2). As such other polycarboxylic acid units, low-molecular dicarboxylic acid units are preferably used, and examples thereof include succinic acid, methylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and aliphatic acids such as sebacic acid. Units of dicarboxylic acids;
Units of an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; units of an aromatic dicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; and the like, with aliphatic dicarboxylic acid being preferred. These polycarboxylic acid units are derived from the corresponding polycarboxylic acid or its ester derivative.

These polycarboxylic acids may be used alone or as a mixture of two or more. Further, a unit of a polycarboxylic acid having three or more functionalities may be contained. The content of the polycarboxylic acid units other than the dicarboxylic acid unit represented by the formula (2) is desirably less than 20 mol% based on the total amount of the polycarboxylic acid units constituting the polyester.

The diol unit represented by the formula (3) includes, for example, propylene glycol, 2-methyl-
1,3-propanediol, 1,3-butylene glycol, 2-methyl-1,4-butanediol, 2-isopropyl-1,4-butanediol, 3-methyl-1,5
-Pentanediol, 2-methyl-1,8-octanediol, 2,7-dimethyl-1,8-octanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9-nonane Diol, 2,2-diethyl-
1,3-propanediol, 2-butyl-2-ethyl-
A unit of an aliphatic diol such as 1,3-propanediol;
Examples of alicyclic diol units such as 1,4-cyclohexanediol, cyclohexanedimethanol, 3 (or 4), 8 (or 9) -dihydroxytricyclo (5.2.1.0 ^2,6 ) decane and the like. . These diols are
It is appropriately selected and used depending on the use of the obtained polyester. These diols may be used alone or as a mixture of two or more.

The polyester of the present invention may be an aromatic ring-containing diol such as 1,4-bis (β-hydroxyethoxy) benzene or bis (β-hydroxyethoxy) terephthalate as long as the gist of the invention is not impaired. May be contained. Also, trimethylolpropane, trimethylolethane, glycerin, 1,2,6-
It may contain a unit of a polyol having three or more functionalities such as hexanetriol and 1,2,4-butanetriol.

The polyester of the present invention is 300 to 3000
It is necessary to have a number average molecular weight of 0. When the number average molecular weight of the polyester is less than 300, the low-temperature properties and flexibility of the polyurethane or polyester polyamide obtained from the polyester become poor, and when the number average molecular weight of the polyester is more than 30,000, the polyurethane or the polyester obtained from the polyester The mechanical properties such as strength and flexibility of the polyamide become poor. The polyester preferably has a number average molecular weight in the range of 700 to 20,000.

When the polyester of the present invention is used for applications such as production of polyurethane, it is necessary that the polyester has a hydroxyl group at a molecular terminal. Further, when used for applications such as production of polyamide elastomer, it is necessary to have a carboxyl group at the molecular terminal. The terminal structure of the polyester can be appropriately adjusted by changing the charged molar ratio of the polyol component as the raw material and the polycarboxylic acid component.

The number of hydroxyl groups or carboxyl groups present in the polyester is different depending on the intended use, but the number of hydroxyl groups or carboxyl groups is generally 2 or more per molecule, and more preferably 2 to 3 per molecule. If
Polyester can be used for most applications and has versatility.

The method for producing the polyester of the present invention is not particularly limited, and a known polyester polycondensation method can be applied. For example, 3-methylpentanedioic acid or an ester derivative thereof and a diol component are charged at a predetermined ratio, an esterification or transesterification reaction is performed, and the obtained reaction product is subjected to high temperature and vacuum in the presence of a polycondensation catalyst. Further, a polyester having a desired molecular weight can be produced by a polycondensation reaction. A wide range of polycondensation catalysts can be used for the production of polyester. Such polycondensation catalysts include, for example, tetramethoxytitanium, tetraethoxytitanium, tetra-titanium
n-propoxytitanium, tetraisopropoxytitanium,
Titanium compounds such as tetrabutoxytitanium; di-n-butyltin oxide, di-n-butyltin dilaurate,
Tin compounds such as dibutyltin diacetate; and combinations of acetates such as magnesium, calcium, and zinc with antimony oxide or the above titanium compounds. These polycondensation catalysts are used in an amount of 5 to
It is preferable to use it within the range of 500 ppm.

The polyester obtained according to the present invention has excellent hydrolysis resistance and does not have a tendency to crystallize, and when used as a raw material for producing paints, adhesives, polyurethanes, polyamide elastomers and polyester elastomers, Gives products with excellent hydrolysis resistance and the like. Further, the polyester obtained by the present invention is a novel high-performance material applicable to various other uses.

[0021]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, measurement of the number average molecular weight of polyester and evaluation of hydrolysis resistance were performed by the following methods.測定 Measurement of number average molecular weight It was determined by calculation based on the hydroxyl value and acid value of the polyester. ◎ Evaluation of hydrolysis resistance 0.5 g of polyester was placed in 10 ml of hot water at 100 ° C.
After immersion for one day, the acid values of water and polyester were measured according to JIS K1577, and the sum of the two was taken as the acid value and used as an index of hydrolysis resistance. The smaller the acid value, the better the hydrolysis resistance.

Example 1 452 g of 3-methylpentanedioic acid and 3-methyl-
560 g of 1,5-pentanediol is charged into a reactor,
The mixture was heated to 200 ° C. in a nitrogen atmosphere under normal pressure, and an esterification reaction was carried out while distilling off generated water out of the reaction system. At the time when the amount of generated water was reduced, 15 mg of tetraisopropyl titanate was added, and 200
The reaction was continued while reducing the pressure to １００100 mmHg. When the acid value reached 1.0 KOH mg / g, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. As a result, a hydroxyl value of 56.1 KOH mg / g and an acid value of 0.20 K
A polyester having OH mg / g and a number average molecular weight of 2,000 (hereinafter abbreviated as polyester A) was obtained. The hydrolysis resistance of polyester A was measured according to the method described above. Table 1 shows the results.

Example 2 and Comparative Examples 1 to 3 The diol component and dicarboxylic acid component shown in Table 1 were used in the same molar ratio as in Example 1, and the esterification reaction and the polycondensation reaction were carried out in the same manner as in Example 1. Thus, a polyester (hereinafter, the polyester obtained in Example 2 is abbreviated as polyester B, and the polyesters obtained in Comparative Examples 1 to 3 are abbreviated as polyesters CE, respectively) was obtained. Table 1 shows the physical properties of the polyesters B to E. Among the polyesters A to E, polyesters A to D were low-viscosity liquids at 20 ° C, and polyester E was a solid at 20 ° C. The hydrolysis resistance of polyesters BE was measured according to the method described above. Table 1 shows the results.

Reference Example 100 g (0.05 mol) of each of polyesters A to E obtained in Examples 1 and 2 and Comparative Examples 1 to 3, 9 g (0.10 mol) of 1,4-butanediol, 4,4 37.5 g (0.15 mol) of '-diphenylmethane diisocyanate and 340 g of dimethylformamide were mixed and reacted at 80 ° C. for 8 hours to obtain a DMF solution of polyurethane (nonvolatile content: about 30% by weight). DMF of polyurethane obtained
The solution was cast on a glass plate and dried to produce a dry film having a thickness of 100 μm. 100 ° C.
The film was allowed to stand in hot water for 7 days, and before and after that, the breaking strength of the film was measured, and the retention (%) of the breaking strength was determined according to the following formula, and used as an index of the hydrolysis resistance of the polyurethane. The breaking strength of the film was measured using a dumbbell-shaped test piece prepared from the film and a tensile speed of 50 cm using an Instron universal testing machine (manufactured by Instron).
/ Min. Retention rate of breaking strength (%) = (breaking strength after leaving in hot water for 7 days) / (rupture strength before leaving in hot water for 7 days) × 100 The results are also shown in Table 1. (The retention of the above breaking strength was described as the hydrolysis resistance of polyurethane.)

[0025]

[Table 1]

In Table 1, the dicarboxylic acid component and the diol component are indicated by the following abbreviations, respectively. MGA: 3-methylpentanedioic acid AD: adipic acid MPD: 3-methyl-1,5-pentanediol BD: 1,4-butanediol From the results in Table 1, a repeating unit represented by the formula (1) It can be seen that the polyesters A and B containing the polyester have improved hydrolysis resistance as compared with the polyesters CE which do not contain the repeating unit represented by the formula (1). Further, polyurethanes obtained from polyesters A and B are excellent in hydrolysis resistance.

[0027]

According to the present invention, hydrolysis resistance is excellent,
A polyester that does not have a tendency to crystallize and has excellent handleability, and that has excellent hydrolysis resistance when used for applications such as paints, adhesives, polyurethanes, polyamide elastomers and polyester elastomers. A new polyester is provided.

Claims (1)

[Claims] 1. A compound represented by the following formula (1): —CO—CH ₂ —CH (CH ₃ ) —CH ₂ —CO—O—R—O— (1) At least one group selected from the group consisting of 20 alkylene groups and a cycloalkylene group which may have branching), and a number average molecular weight of from 300 to 30,000 A polyester characterized by the following.