JPH0566405B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing polyester elastomer. More specifically, the present invention relates to a method for stable melt polycondensation of a polyester elastomer using a polymer obtained by adding ethylene oxide to the terminal group of polypropylene oxide glycol as the polyether glycol to be copolymerized. <Conventional technology> Addition polymer of ethylene oxide to the terminal group of polypropylene oxide glycol (hereinafter referred to as EO)
-Polyether ester copolymers copolymerized with
55-147546). Polyether ester using EO-PPG has better compatibility with polyester, which is a hard segment, than the conventional well-known polyether ester using polytetramethylene glycol. Therefore, it has the characteristic that it can be made more flexible without significantly lowering the softening temperature. However, since EO-PPG contains relatively thermally unstable propylene oxide units,
The resulting polymer does not have sufficient thermal stability or oxidative decomposition resistance, and in particular, the molten polymer extruded from the reaction tank after the polymerization reaction is white with a marked off-odor when exposed to air. This method not only generates smoke and deteriorates the working environment, but also has the drawback of deteriorating the physical properties of the polymer. <Problems to be solved by the invention> In view of the drawbacks of the prior art, the present invention solves the problems of the EO.
- The purpose is to improve the thermal stability of the polymer during melt polycondensation when producing a polyetherester copolymer using PPG as a copolymerization component.
That is, the purpose is to prevent smoke from being generated from the polymer during discharge after the completion of the polycondensation reaction. <Means for Solving the Problems> As a result of intensive research to achieve the above object, the present inventors found that improvement of the thermal stability of the present polyetherester copolymer during melt polycondensation can be achieved by The present invention was achieved by discovering that there is a key to the combined use of a tin compound and a heat stabilizer contained in polycondensation, and that there is a significant difference in stabilizing effect depending on the type of stabilizer. That is, the present invention provides: A dicarboxylic acid mainly containing terephthalic acid and/or its ester-forming derivative; B low molecular weight glycol mainly containing 1,4-butanediol and/or its ester-forming derivative; C polypropylene oxide Polyether glycol and/or its ester-forming derivative having a molecular weight of 1,500 to 3,500 and an addition-polymerized ethylene oxide content of 15 to 35% by weight, which is a polymer in which ethylene oxide is added to the end group of glycol.D Approximately 1.0 per 100 moles of dicarboxylic acid. When producing a polyester elastomer comprising ~7.0 mol of a branching agent having a functionality of 3 to 6, a heat stabilizer having a structure represented by the formula () is added in the presence of a tin compound to stably stabilize the weight. The present invention relates to a method for producing a polyester elastomer, which is characterized by carrying out condensation. X = alkyl, aryl, isocyanurate; R = tertiary butyl n = 2-4 The heat stabilizer represented by the formula () added in the present invention is a hindered phenol type, and specific examples include 1, 3, 5-trimethyl-2,4,6
-tris(3,5-ditarsiabutyl-4-
hydroxybenzyl)benzene (a), tris(3,
5-di-tertyabutyl-4-hydroxybenzyl) isocyanurate (b), 2-methyl-1,3
-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane (c) and the like. The heat stabilizer is usually added between the start of the esterification reaction and before the completion of the polycondensation reaction in the production of polyester elastomer, but a particularly desirable addition time is to add it simultaneously with the addition of EO-PPG. The amount of the heat stabilizer added varies depending on the polycondensation conditions, but is usually 0.01 to 2.0% by weight per unit weight of the final polyester elastomer.
, preferably 0.05 to 1.0% by weight. If it is less than 0.01% by weight, the effect of stabilizing the polymer will be small, while if it is more than 2.0% by weight, it will deteriorate the quality of the polymer, especially the color tone, which is not preferable. In addition, hindered phenol stabilizers other than the present stabilizer, such as pentaerythrityl-tetrakis [3-(3,5-di-tert-butyl-4-
Hydroxyphenyl) propionate] (CIBA
- GEIGY "Irganox" 1010), N,N'-hexamethylene bis(3,5-di-tertiarybutyl-4-hydroxy-hydrocinnamamide)
(CIBA-GEIGY “Irganox” 1098), 2,2′-
Thiodiethyl bis-[3-(3,5-di-tertiarybutyl-4-hydroxyphenyl)propionate] (CIBA-GEIGY “Irganox” 1035) has little or no effect, or even if it does, the amount added is It has the disadvantage that it has to be added in a much larger amount than the heat stabilizer represented by formula (). Furthermore, the tin compound used in the present invention is
Organic tin compounds are preferred, such as monoalkyltin compounds, monoaryltin compounds, dialkyltin compounds, diaryltin compounds, trialkyltin compounds, triaryltin compounds, tetraalkyltin compounds, and the like. Specifically, mono n-
Monoalkyltin compounds such as butyl hydroxytin oxide, mono n-butyltin triacetate, mono n-butyltin monooctylate, and mono n-butyltin monoacetate are particularly preferably used because they are useful as catalysts for esterification reactions. Use one of these, but if you prefer,
Several types can also be used in combination. The amount of tin compound added varies depending on the polycondensation conditions, but the amount of tin atoms is 0.002% by weight based on the final polyether ester copolymer.
A range of 0.1% to 0.1% by weight is preferred, and 0.003 to 0.03% by weight is particularly preferred. If the amount of the tin compound added is too small, a sufficient stabilizing effect cannot be obtained, while if the amount added is too large, the polymer tends to be colored and foreign substances are likely to be generated. The tin compound may be added at any time from the start of the esterification reaction to the time when the stabilizer is added, but the most preferable addition time is at the start of the esterification reaction. The short chain ester units constituting the hard segment of the polyether ester copolymer of the present invention mainly consist of 1,-butylene terephthalate. In other words, terephthalic acid is
It is necessary to use 50 mol% or more, preferably 60 mol% or more. Other dicarboxylic acids that can be copolymerized with terephthalic acid include isophthalic acid, phthalic acid, p-oxybenzoic acid, m-oxybenzoic acid, Examples include aromatic, aliphatic, and alicyclic dicarboxylic acids such as naphthalene dicarboxylic acid, oxalic acid, adipic acid, sebacic acid, and cyclohexane dicarboxylic acid. A particularly preferred dicarboxylic acid is isophthalic acid. Furthermore, 1,4-butanediol accounts for 50 mol% or more, preferably 60 mol% or more of the total low molecular weight glycols. Other low molecular weight glycol components that can be copolymerized with 1,4-butanediol include ethylene glycol, propylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, p-xylylene glycol, cyclohexane glycol, cyclohexanedimethanol, etc. You can choose from aromatic, aliphatic, alicyclic glycols, etc. On the other hand, the components that make up the soft segment
The number average molecular weight of EO-PPG is 1500-3500. If the number average molecular weight is less than 1500, the curing speed will be unsatisfactory, and the deformation temperature and oil resistance, which are characteristics of polyether ester using EO-PPG, will not improve. Moreover, if it is 3,500 or more, the compatibility with the polybutylene terephthalate component, which is a hard segment, becomes poor and the physical properties of the polymer deteriorate, which is not preferable. A particularly preferred number average molecular weight is 1,700 to 2,500. The amount of the copolymerized polyether glycol contained in the polyester elastomer is from 10 to 70% by weight, based on the polymer. Further, the content of ethylene oxide to be addition-polymerized to polypropylene oxide glycol is 15 to 35% by weight based on the total amount of the polymer. If the ethylene oxide content is lower than this, the polycondensation reactivity is lowered and phase separation is likely to occur, while if it is higher than this, the copolymer will swell excessively with water, which is not preferable. Furthermore, the present polyetherester has a functionality of 3 to
Contains 6 branching agents. The amount of branching agent is aromatic dibasic acid
Approximately 1.0 to 7.0 moles per 100 moles. Below 1.0 mol, it becomes increasingly difficult to obtain a polymer with sufficient melt viscosity, while polymers containing more than 0.7 mol of branching agent have significantly impaired physical properties as molded articles. Typical compounds that can be used as branching agents include polycarboxylic acids, such as trimellitic acid, hemimellitic acid, pyromellitic acid,
1,1,2,2-ethanetetracarboxylic acid, 1,
3,5-pentatricarboxylic acid and 1,2,3,
There is 4-cyclopentanetricarboxylic acid. These are used as they are, or preferably in the form of an acid anhydride when an intramolecular anhydride is formed. Polyols are other typical compounds that can be used as branching agents, such as glycerol, trimethylolpropane, pentaerythritol,
Polyols such as 1,2,6-hexanetriol, sorbitol, 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane, tris(2-hydroxyethyl)isocyanurate, dipentaerythritol, and ethylene oxide propylene such as glycidyl groups Examples include compounds equivalent to polyols having an oxide structure at the end, such as diglycidyl ethers of glycols and diglycidyl esters of dicarboxylic acids. Furthermore, typical compounds that can be used as branching agents include oxyacids, such as malic acid, citric acid, tartaric acid, 3-hydroxyglutaric acid, myucic acid, trihydroxyglutaric acid, and 4-(β-hydroxyethyl)phthalic acid. can be given. Among the above, a particularly preferred branching agent is trimellitic anhydride. These branching agents may be added at any time after the start of the esterification reaction and before the addition of the polyether glycol, but it is particularly preferably added at the start of the esterification reaction. Esterification and polycondensation reactions of the polyether ester copolymer can be carried out by known methods. For example, after performing an esterification reaction of a dicarboxylic acid with a low molecular weight glycol in the presence of a branching agent and appropriate catalysts, a polycondensation catalyst, a heat stabilizer and the polyether glycol are added, and the polycondensation is carried out by heating under reduced pressure. This is the way to do it. Here, as the esterification reaction catalyst and the polycondensation catalyst, conventionally known reaction catalysts such as titanium compounds can be used.
Specifically, examples thereof include tetraalkyl titanates, reaction products of tetraalkyl titanates and alkylene glycols, partial hydrolysates of tetraalkyl titanates, metal salts of titanium hexaalkoxide, titanium carboxylates, titanyl compounds, and the like. It goes without saying that known matting agents, modifiers and other additives can be used in the polycondensation reaction if necessary. Even in this case, the effects of the present invention remain unchanged. <Example> As described above, according to the present invention, the thermal stability of the molten polymer is improved when producing the polyether ester by using a specific thermal stabilizer in the presence of a tin compound. Examples will specifically explain these effects. In addition, the relative viscosity in the examples is 8
% o-chlorophenol at 25°C. Example 1 The following raw materials were charged into an esterification reactor equipped with a stirring device and a rectification column. Terephthalic acid 55.0Kg Isophthalic acid 16.0Kg Trimellitic anhydride 410.5g 1,4-butanediol 69.3Kg Tetrabutyl titanate 47.0g Mono-n-butylhydroxytin oxide 16.0g After the addition was completed, the temperature was gradually raised while stirring. Water, a reaction product, began to distill out, and after 3 hours and 30 minutes, almost the theoretical amount of water had been distilled out. 288 g of tetrabutyl titanate was added to the reaction mixture.
1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiarybutyl-4-hydroxybenzyl)benzene (CIBA.GEIGY "Irganox") was added as a heat stabilizer. 1330) to 160
g (0.1% by weight based on the resulting polymer) was added. Next, this esterification reaction product was converted into EO-PPG.
(Number average molecular weight approximately 2150, ethylene oxide content
After transferring to the polymerization reactor containing 68.8Kg (33% by weight), the polymerization temperature was maintained at 245℃, and 0.9mm was removed in 40 minutes.
The degree of vacuum was set to below Hg. After continuing the polymerization reaction for 3 hours and 30 minutes, stirring was stopped, and the polymer was extruded into water in the form of a strand from the discharge port at the bottom of the reactor under pressure with nitrogen gas. Next, this material was cut into chips of uniform size. The relative viscosity of the obtained polymer was 48.2. At this time, when the molten polymer at about 220 to 240° C. was extruded from the 8-hole outlet at a rate of about 4 kg per minute, no smoke due to decomposition was observed from the polymer throughout the extrusion. Comparative Examples 1 to 3 In Example 1, the system without the addition of a tin compound (mono-n-butylhydroxytin oxide) and the heat stabilizer were replaced with pentaerythrityl-tetrakis[3-
(3,5-di-tertiarybutyl-4-hydroxyphenyl)propionate] (CIBA-GEIGY
Polymerization and discharge were carried out in the same manner as in Example 1 in a two-reaction system with and without mono-n-butylhydroxytin oxide. The smoke generation situation during discharge was as shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1 A dicarboxylic acid mainly consisting of terephthalic acid and/or its ester-forming derivative, B low molecular weight glycol mainly consisting of 1,4-butanediol and/or its ester-forming derivative, C polypropylene Polyether glycol and/or its ester-forming derivative having a molecular weight of 1500 to 3500 and an addition-polymerized ethylene oxide content of 15 to 35% by weight, which is a polymer in which ethylene oxide is added to the terminal group of oxide glycol, D. Approximately per 100 moles of dicarboxylic acid. When producing a polyester elastomer comprising a branching agent having a functionality of 3 to 6 and containing 1.0 to 7.0 moles, a heat stabilizer having a structure represented by the formula () is added in the presence of a tin compound. A method for producing polyester elastomer. X = alkyl, aryl, isocyanurate; R = tertiary butyl n = 2-4 2 The amount of the heat stabilizer having the structure represented by the formula () is 0.01 to 0.01 per unit weight of the produced polymer.
2.0% by weight, and the amount of tin compound added is the amount of tin atoms per unit weight of the produced polymer,
The method according to claim 1, wherein the amount is 0.002% to 0.1% by weight.