JPS5810429B2 - Polyester elastomer - Google Patents

Description

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

More specifically, the present invention aims to provide a method for improving the oxidation resistance and weather resistance of polyester elastomers at high temperatures.

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 of their excellent bending fatigue resistance and low-temperature properties.

Polyester elastomers include, for example, terephthalic acid,
It can be obtained by polycondensing tetramethylene glycol, polyoxytetramethylene glycol, etc. using a specific catalyst such as an organic titanium compound (Japanese Patent Laid-Open No. 47-25295).
(see specification).

However, when polyester elastomer is used alone, it deteriorates due to the action of oxygen in the air and light.

Therefore, various stabilizers are added to polyester elastomers for the purpose of preventing deterioration phenomena.

However, these have drawbacks such as insufficient effects, scattering during polymerization or molding, or coloring of the polymer when added, and none of them are satisfactory.

As a result of intensive research into a method for stabilizing polyester elastomers that does not have such drawbacks, the present inventors have found that a compound represented by the following general formula (1) and a compound represented by the following general formula [■] and/or (■) The present inventors have discovered that by adding these compounds at any stage of polyester elastomer production, the thermal stability and light stability of the polyester elastomer can be significantly improved, and the color tone can also be maintained in a favorable state. .

That is, the present invention provides (A) dicarboxylic acids and/or ester-forming derivatives thereof, (B) low molecular weight glycols and/or ester-forming derivatives thereof, and (C) polyoxyalkylene glycols having an average molecular weight of 500 to 5,000 and/or ester-forming derivatives thereof. When stabilizing the polyester elastomer obtained by polycondensing the three sex derivatives so that component C accounts for 10 to 90% of the total weight of the polyester elastomer, the molding of the polyester elastomer is completed from the raw material preparation stage of the polyester elastomer. (1) General formula (I) (However, R1 is an alkylene group having 2 to 12 carbon atoms.)

) and (2) general formula (■] (However, R3 and R4 are the same or different hydrogen atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 2 to 10 carbon atoms) , Xl is a halogen atom, and n is 0 or 1.

) and/or general formula (provided that it is a hydrogen atom, an alkoxy group, or a hydroxyl group).

) is a method for stabilizing a polyester elastomer, which is characterized by adding one or more of the compounds shown below.

The dicarboxylic acid used as component (A) constituting the polyester elastomer preferably has at least 55 molar force occupied by only one type of dicarboxylic acid, and the dicarboxylic acid is preferably an aromatic dicarboxylic acid.

Preferred aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid,
-naphthalene dicarboxylic acid, diphenyl-4,4'
-dicarboxylic acid, 3,3'-dimethyldiphenyl-4
, 4'-dicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid and the like.

Although aliphatic dicarboxylic acids and alicyclic dicarboxylic acids can also be used, it is preferable to limit these to 45% or less of component (A).

Such dicarboxylic acids include oxalic acid, adipic acid,
Examples include cepatic acid, 1,4-cyclohexanedicarboxylic acid, and decahydronaphthalene-2,6-dicarboxylic acid.

The dicarboxylic acids may be used alone or in combination of two or more.

Similar to the dicarboxylic acids mentioned above, their ester-forming derivatives can also be used.

Examples of such ester-forming derivatives include methyl ester,
Examples include lower alkyl esters such as ethyl ester, substituted aliphatic esters such as 2-hydroxyethyl ester, aryl esters such as phenyl ester, carbonic acid esters, and acid halides.

As the component (B), aliphatic glycols such as tetramethylene glycol, hexamethylene glycol, etc. are preferably used, but glycols containing aromatic groups such as bishydroxyethoxybisphenol A, 4,4'-bishydroxyethoxydiphenyl sulfone, etc. Glycols having alicyclic groups such as glycol and cyclohexanedimetatool can also be used.

The glycol used as component (B) preferably has a molecular weight of 400 or less.

Similar to the glycols mentioned above, ester-forming derivatives thereof can also be used.

Examples of such ester-forming derivatives include monoesters and diesters with monocarboxylic acids.

Oxycarboxylic acids and ester-forming derivatives thereof can also be used as part of the components (5) and (B).

An example of a preferred oxycarboxylic acid is p-hydroxybenzoic acid.

As the component (C), polyoxyalkylene glycol having an average molecular weight of 500 to 5,000 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.

The polyoxyalkylene glycol oxyethylene glycol, polyoxyethylene glycol, poly-1,2-butylene ether glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, polyoxyheptamethylene glycol, polyoxyoctamethylene glycol, polyoxy Examples include nonamethylene glycol.

Among these, polyoxytetramethylene glycol is particularly preferred.

As the polyoxyalkylene glycol, not only non-copolymerized polyoxyalkylene glycols but also random or block copolymerized polyoxyalkylene glycols can be used.

An ethylene oxide propylene oxide copolymer is exemplified as a typical copolymer.

For copolymers, 80 mol% of the number of repeating units.
Preferably, the above groups are occupied by one type of oxyalkylene group.

The polyoxyalkylene glycols may be used alone or in combination of two or more.

In this case, it is preferable that 80 mol% or more of the number of repeating units in the mixed polyoxyalkylene glycol be accounted for by one type of oxyalkylene group.

Similar to the above-mentioned polyoxyalkylene glycol, its ester-forming derivative 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 polyoxyalkylene component accounts for 10 to 90% by weight, particularly 20 to 70% by weight, of the polyester produced.

The polyoxyalkylene component referred to herein refers to a polyoxyalkylene moiety composed only of repeating units of the polyoxyalkylene glycol or its ester-forming derivative.

In order to produce a polyester elastomer, the above (A)
, (B) and (C) components may be polycondensed by any method.

During polycondensation, ■ the above (A), (B), (C
) A method of starting polycondensation after charging all three components ■ After charging both components (A) and (B) and causing them to polycondense, add component (C) and copolymerize. Method for completing the condensation ■ Any method can be used, such as a method in which the above-mentioned (A) and (C) components are charged and polycondensed to a certain extent, and then the (B) component is added and copolymerized to complete the polycondensation. used.

As a reaction catalyst, a conventionally known transesterification catalyst and/or polymerization catalyst can be used.

In particular, it is preferable to use organic titanates as catalysts.

One of the stabilizers used in the present invention is of the general formula (I) (However, R1 is an alkylene group having 2 to 12 carbon atoms.

) is a compound represented by

Examples of the alkylene group for R1 in the general formula (1) include ethylene group, propylene group, butylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, dodecamethylene group, etc. be done.

A representative compound is N,N'-ethylenebis(3
-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], N,N'-propylene bis(3
-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide].

N,N'-hexamethylenebis(3-(3,5-di-t)
-butyl-4-hydroxyphenyl)propionamide), N,N'-dodecamethylenebis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide), N,N'-pentamethylene Bis(3-3,5-
di-t-butyl-4-hydroxyphenyl)propionamide].

N,N'-octamethylenebis(3-(3,5-di-t)
-butyl-4-hydroxyphenyl)propionamide], N,N'-nonamethylenebis[3-(3,5-di-
Examples include t-butyl-4-hydroxyphenyl)propionamide), N,N'-decamethylenebis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide), and the like.

Further, the stabilizer used in combination with the compound represented by the general formula [I] is represented by the general formula (■) (However, R3 and R4 are the same or different hydrogen atoms.

It is an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 2 to 10 carbon atoms, Xl is a halogen atom, and n is 0 or 1.

) and/or the general formula (■) (However, R
5 is a hydrogen atom, an alkoxy group or a hydroxyl group.

).

R3 in the general formula (■) above. R4 is a hydrogen atom: an alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, propyl, butyl, t-butyl, or ethoxy.

It is an alkoxy group having 2 to 10 carbon atoms such as butoxy, octoxy, etc.

Xl is a halogen atom such as a chlorine atom, a bromine atom, etc.

Representative examples of the compound represented by the general formula 1 include 2-(2-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2
'-Hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dimethylphenyl)benzotriazole, 2-(2' -hydroxy-37-1-butylphenyl)benzotriazole.

2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxyphenyl)-5-chlorobenzotriazole, 2-(
2'-hydroxy-57-ethoxyphenyl)benztriazole, 2-(2'-hydroxy-5'-butoxyphenyl)-5-chlorobenzotriazole, 2-(2
Examples include '-hydroxy-37-methyl-5'-ethoxyphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole.

Further, R5 in the general formula (■) is a hydrogen atom: an alkoxy group such as methoxy, octoxy, or ethoxy: a hydroxy group.

Representative examples of the compound represented by the general formula (■) include 2-hydroxy-5-methylbenzophenone, 2-hydroxy-5-methylbenzophenone, and
, 4-dihydroxybenzophenone, 2-hydroxy-
4-methoxybenzophenone, 2-hydroxy-4-n
-Octoxybenzophenone, 2-hydroxybenzophenone, 2,5-hydroxybenzophenone and the like are exemplified.

The stabilizer may be added at any stage from the stage of raw material preparation of the polyester elastomer to the completion of molding of the polyester elastomer.

The amount of the stabilizer compound represented by the general formula (I) is preferably 0.001 to 5% by weight based on the polyester;
Particularly preferred is 0.005 to 2% by weight.

If it is less than 0.001% by weight, the effect of the present invention is not sufficient, and if it is more than 5% by weight, the effect does not increase and tends to reach a plateau.

Further, the amount of the compound represented by the general formulas (■) and (■) is preferably 0.001 to 3% by weight, particularly preferably 0.01 to 1% by weight, based on the polyester.

If it is less than 0.001% by weight, the effect of the present invention is not sufficient, and if it is more than 3% by weight, the effect does not increase and tends to reach a plateau.

The polyester elastomer stabilized by the method of the present invention has excellent thermal oxidation resistance and ultraviolet resistance.

Carbon black, titanium oxide, pigments, other modifiers, etc. can be added to the polyester elastomer stabilized by the method of the present invention.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In exogenous terms, "parts" means parts by weight.

Further, the reduced specific viscosity is a value measured at 35° C. by dissolving 120 mg of the sample polymer in 10 ml of 0-chlorophenol, and (COOH) represents the molar equivalent of carboxyl groups per 106 g of the polymer.

Examples 1 to 5 and Comparative Example 1 558 parts of dimethyl terephthalate and 3 parts of tetramethylene glycol were placed in a reactor equipped with a stirrer, a distiller, and a nitrogen introduction tube.
88 parts, 90.8 parts of polyoxytetramethylene glycol with an average molecular weight of 2,000 (6 parts of this component in the total polymer)
0% by weight) and 0.0245 parts of tetrabutoxy titanate were charged, heated to 180 to 220°C to distill out 90% of the theoretical amount of methanol produced, and then the temperature was raised to 240°C. The reaction was carried out at normal pressure for 30 minutes, then in a weak vacuum of about 30 mmHgabs for 30 minutes.
The mixture was reacted for 200 minutes, and further polymerized for 200 minutes under high vacuum of 0.1 to 0.3 mmHgabs.

Next, the thread was returned to normal pressure with nitrogen, and 0.75 parts of N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyphenyl)propionamide (0.5 parts based on the polymer) % by weight) and the prescribed light stabilizer (see Table 1) 0.
15 parts (0.1% by weight based on polymer) and 1
Stirred for 0 minutes.

The obtained polyester elastomer was made into chips and
It was vacuum dried at ℃ for 5 hours and molded.

The reduced specific viscosity (ηsp/C) of the obtained sample was 2.1
3, (COOH) was 11.2.

As a result of irradiating the sample with a weather-o-meter for 48 hours, ηsp/C, its retention rate, and (COOH) value were
It was as shown in the table.

Example 6 Contains 0.5% by weight (based on the polymer) of N,N'-hexamethylenebis(3,5-di-butyl-4-hydroxyphenyl)propionamide, polymerized by the same method as in Example 1. polyester elastomer,
2-Hydroxy-4-methoxybenzophenone 0.07
5 parts (0.05% by weight based on polymer) and 2-(2
-hydroxy-4-octoxyphenyl)benzotriazole 0.075 part (0.05% by weight based on polymer)
) and mixed for 10 minutes.

The obtained polyester elastomer was made into chips and
It was vacuum dried at ℃ for 5 hours and molded.

The reduced specific viscosity (ηSP/C) of the obtained sample was 1.9
5° (COOH) was 12.6.

Next, the sample was irradiated with a weatherometer for 48 hours, and the result was ηSP/C of 1.37. The retention rate of ηSP/C is 70
．． 5%, (COOH) was 29.4.

Example 7 1 part of N,N'-butylenebis(3,5-t-butyl-4-hydroxyphenyl)propionamide and 2-hydroxy-3-t-butyl were added to a polyester elastomer polymerized by the method shown in Example 1. 1 part of -5-methylbenzotriazole was added.

The obtained polyester elastomer was molded to obtain a sample.

The reduced specific viscosity (ηSP/C) of this sample is 2.08
, (COOH) was 11.8.

The sample was then irradiated with a weatherometer for 48 hours, and as a result, ηSP/C was 1.50°, the retention rate of ηSP/C was 72.6%, and [C00H) was 21.7.

Example 8 N,N'-dodecamethylene bis(3,5-
di-t-butyl-4-hydroxy)propionamide 1
and 2-(2'-hydroxy-3',5'-di-t-
butyl)-5-chlorobenzotriazole 0.5 part and 2
, 0.04 part of 4-dihydroxybensylenon was added.

The obtained polyester elastomer was molded to obtain a sample.

The reduced specific viscosity (ηSP/C) of this sample is 2.05
, (COOH) was 12.3.

Next, the sample was irradiated with a weatherometer for 48 hours, and as a result, ηSP/C was 1.47°, the retention rate of ηSP/C was 71.8%, and (COOH) was 20.8.

Claims (1)

[Scope of Claims] 1 (A) Dicarboxylic acid and/or its ester-forming derivative (B) Low molecular weight glycol and/or its ester-forming derivative (C) Polyoxyalkylene glycol with an average molecular weight of 500 to 5,000 and/or When stabilizing a polyester elastomer obtained by polycondensing three of the three ester-forming derivatives thereof such that the C component accounts for 10 to 90% of the total weight of the polyester elastomer, the polyester elastomer can be stabilized from the raw material preparation stage of the polyester elastomer. At any stage until the completion of molding, one or more compounds represented by (1) general formula (wherein R1 is an alkylene group having 2 to 12 carbon atoms) and (2) general formula (however, R3, R4 are the same or different hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, or alkoxy groups having 2 to 10 carbon atoms, Xl is a halogen atom, and n is 0 or 1.
It is. ) and (or) one or more compounds represented by the general formula (wherein R5 is a hydrogen atom, an alkoxy group, or a hydroxy group). Methods for stabilizing elastomers.