JPH0340732B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to polyester elastomers with improved moldability, rubber properties and low temperature flexibility. More specifically, the present invention relates to a polyether ester block copolymer which is obtained by copolymerizing a specific amount of a high molecular weight poly(tetramethylene oxide) glycol with a narrow molecular weight distribution and has particularly improved low temperature properties. The main hard segment is polybutylene terephthalate, and poly(tetramethylene oxide)
The polyether ester block copolymer with glycol as a soft segment has excellent properties such as flexibility, elasticity, mechanical strength, oil resistance, chemical resistance, and heat resistance, and because it is thermoplastic, it can be processed using the same technology as plastics. Because of its advantage of being able to be formed into plastic, it came to be used in the fields of rubber and flexible plastics. In particular, the content of polyether soft segments is generally in the range of approximately 15 to 50% by weight, and in order to take advantage of the characteristics of high crystallinity and high strength of polybutylene terephthalate hard segments, the polyether content is is suppressed to a small amount of components. In this polyether ester, poly(tetramethylene oxide) glycol having a number average molecular weight of 1000 has generally been used as the soft segment. The reason for this is mainly that the compatibility of poly(tetramethylene oxide) glycol with the polybutylene terephthalate hard segment has a strong correlation with the molecular weight of poly(tetramethylene oxide) glycol. The problems include the formation of agglomerated phases of poly(tetramethylene oxide) glycol, coarse phase separation, poor physical properties, and poor fluidity of the molten polymer. These phenomena are also shown in JP-A-49-31795, for example, and the larger the number average molecular weight of poly(tetramethylene oxide) glycol, the more coarse phase separation is formed, and the homogeneous copolymer is formed. Furthermore, it has been revealed that when the number average molecular weight is 2000, a homogeneous molten polymer cannot be obtained unless the poly(tetramethylene oxide) glycol content is about 50% by weight or more. If coarse phase separation is formed, the balancing effect will be large, as if it were a two-component blend with poor compatibility, and it will be very difficult to discharge from the polymerization can and form a lump due to draw resonance, and furthermore, extrusion molding will be difficult. This causes problems such as unevenness in ejection at the time of discharging, making it difficult to obtain a good molded product. Poly(tetramethylene oxide) in polyetherester block copolymer
As the molecular weight of glycol increases, the thermal properties of the copolymer, such as melting point and crystallization properties, associated high-temperature mechanical properties, injection moldability, etc., are improved, but in reality, poly(tetramethylene The reality is that oxide) glycols with a number average molecular weight of about 1000 have no choice but to be used. Therefore, the present inventors first conducted various studies on the effects of the number average molecular weight and molecular weight distribution of poly(tetramethylene oxide) glycol on the structure of polyether ester block copolymers, particularly on the phase separation structure and physical properties. For relatively hard elastomers containing 5 to 50% by weight of copolymers of tetramethylene oxide) glycol, poly(tetramethylene oxide) glycol, which has a narrow molecular weight distribution, can be used with a number average molecular weight of approximately 1500.
Even in the polymer range of ~2500, there is no formation of coarse phase separation (almost transparent when melted), fluidity, thermal properties,
They discovered that it was possible to make a block copolymer with improved rubber elasticity and filed a patent application (Japanese Patent Laid-Open No. 158497/1983). In the invention application, the present inventors discovered that the copolymer of poly(tetramethylene oxide) glycol
The properties of poly(tetramethylene oxide) glycol, which does not form coarse phase separation, were specified for the copolymer structure range that is relatively small at 50% by weight and is likely to form coarse phase separation, but poly(tetramethylene oxide) Polyether ester block copolymers with a high glycol content of 55% or more by weight do not form coarse phase separation, so no special values are required for the properties of poly(tetramethylene oxide) glycol. The reality is that this could not have been considered. That is, it has been thought that poly(tetramethylene oxide) glycol, which has a wide distribution, can be used for copolymers with a high polyether content that do not cause coarse phase separation. However, when high-molecular-weight poly(tetramethylene oxide) glycol is used at a high copolymerization ratio for the above-mentioned purpose, the poly(tetramethylene oxide) glycol does not degrade under low-temperature conditions of use below -20°C, even though coarse phase separation does not occur. A major problem was that the ether ester block copolymer became hard. Therefore, the present inventors developed a polyether ester block copolymer that has a high copolymerization ratio of poly(tetramethylene oxide) glycol, has excellent moldability and crystallinity, and does not lose flexibility even at low temperatures. We have carefully considered whether to manufacture
This is what led us to the present invention. (1) a dicarboxylic acid component of which at least 90 mol % of the short chain dicarboxylic acid component is terephthalic acid or its ester-forming derivative; (2) at least 90 mol % of the short chain diol component
(3) A short chain diol component which is 1,4-butanediol or its ester-forming derivative, and (3) a number average molecular weight as a long chain diol component.
A polyether ester block copolymer obtained by copolymerizing poly(tetramethylene oxide) glycol with a molecular weight distribution dispersion value α of 1300 to 3000 as shown by the following formula; Polyester elastomer characterized by copolymerizing 55 to 90 wt.
v is the viscosity average molecular weight defined by the following formula. v=anti log ₁₀ (0.493 _{log 10} μ+3.0646) where μ is the melt viscosity at 40° C. in poise. ) Among the above polyether esters, the polyesters constituting the short chain ester hard segment are:
polybutylene terephthalate derived from terephthalic acid and 1,4-butanediol, or
Furthermore, they are derived from comonomers with other dicarboxylic acids and/or other diols. Examples of copolymerizable dicarboxylic acids other than terephthalic acid include isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, and naphthalene-2,7-dicarboxylic acid.
- Aromatic dicarboxylic acids such as dicarboxylic acid, diphenyl-4,4-dicarboxylic acid, diphenoxyethane dicarboxylic acid, sodium 5-sulfoisophthalate, etc., alicyclic dicarboxylic acids such as 1,4-cyclohexane dicarboxylic acid, succinic acid, etc. acids, oxalic acid, adipic acid, sebacic acid, dodecanedioic acid,
Examples include aliphatic dicarboxylic acids such as dimer acids. Of course, ester-forming derivatives of dicarboxylic acids such as lower alkyl esters,
Aryl esters, carbonate esters, and acid halides can also be used at the same time. Examples of diol components other than 1,4-butanediol include aliphatic diols such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol;
Alicyclic diols such as cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanemethanol, xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-
Bis[4-(4-hydroxyethoxy)phenyl]
Examples include diols containing aromatic groups such as propane, bis[4-(2-hydroxy)phenyl]sulfone, and 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane. Such diols can also be used in the form of ester-formable derivatives, such as acetyl derivatives, alkali metal salts, and the like. The main reason why polybutylene terephthalate units are preferable as hard polyester units is that they have a high crystallization rate and excellent moldability, but polyetherester elastomers also have good rubber elasticity, mechanical properties, heat resistance, chemical resistance, etc. It depends on being well-balanced. The polyether forming the soft segment of the polyether ester of the present invention has a number average molecular weight of
The poly(tetramethylene oxide) glycol has a molecular weight distribution of 1,300 to 3,000 and has a molecular weight distribution represented by the following formula (1). Molecular weight distribution dispersion value: α=M/-v/Mn≦1.60 (1) (where n is the number average molecular weight and v is the viscosity average molecular weight defined by the following formula. v=anti log ₁₀ (0.493log ₁₀ μ+3 .0646) Here, μ is the melt viscosity in poise at 40°C.) The molecular weight distribution of poly(tetramethylene oxide) glycol is generally wide, although it depends on the manufacturing method, and the higher the molecular weight, the wider it becomes. Poly(tetramethylene oxide) glycol having a number average molecular weight of about 2000, which is conventionally available as a commercial product, has a dispersion value according to the above formula (1) ranging from 1.9 to 2.5. When a polyether ester block copolymer is synthesized with high molecular weight poly(tetramethylene oxide) glycol having a wide molecular weight distribution accounting for 55 to 90% by weight of the total copolymer, clear coarse phase separation is formed. It is possible to obtain a substantially homogeneous copolymer that is transparent to translucent when melted without any melting. This block copolymer has high rubber elasticity at room temperature, and in particular, the higher the molecular weight poly(tetramethylene oxide) glycol used, the better the moldability. However, this polymer has a major drawback in that it hardens rapidly at low temperatures (-20 to -50°C) and loses elastic recovery. This drawback can be improved by using poly(tetramethylene oxide) glycol with a very narrow molecular weight distribution. The dispersion value of the molecular weight distribution is 1.60 as shown in equation (1).
The narrowness is more preferably 1.50 or less. It is possible to produce poly(tetramethylene oxide) glycol with a narrow molecular weight distribution by selecting reaction conditions and catalysts. For example, TG
Croucher et al., Polymer 17, 205 pages, Canadian Patent No. 800659 and Japanese Patent Publication No. 52-32797, 32798
However, it is of course possible to produce poly(tetramethylene oxide) glycol with a narrow molecular weight distribution by any means such as cationic polymerization conditions, separation and purification of the polymer, and depolymerization. It's okay. A polyether ester block copolymer made of the above-mentioned components can be produced by a known method. For example, lower alcohol diesters of dicarboxylic acids, excess low molecular weight glycols and poly(tetramethylene oxide) glycols are transesterified in the presence of a catalyst, and the resulting reaction product is polycondensed, or dicarboxylic acids and glycols and There is a method in which poly(tetramethylene oxide) glycol is subjected to an esterification reaction in the presence of a catalyst and the resulting product is polycondensed. Alternatively, polybutylene terephthalate is prepared in advance, and then other dicarboxylic acids, diols, or poly(tetramethylene oxide) ) add glycol or
Alternatively, any method such as adding another copolymerized polyester and randomizing it by transesterification may be used. As a common catalyst for transesterification or esterification reactions and polycondensation reactions, Ti catalysts give good results, as well as Mg, Sn,
Metal catalysts such as Pb, Zr, and Zn are useful. Additionally, polycarboxylic acids, polyfunctional hydroxy compounds, oxyacids, and the like may be copolymerized as part of the dicarboxylic acids and glycols. The polyfunctional component effectively acts as a viscosity increasing component, and the range in which it can be copolymerized is 3 mol% or less. Examples of compounds that can be used as such polyfunctional components include trimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, butanetetracarboxylic acid, glycerin, pentaerythritol and their esters and acid anhydrides. can. The polyether ester block copolymer of the present invention can contain heat-resistant and light-resistant stabilizers such as antioxidants, thermal decomposition inhibitors, and ultraviolet absorbers during polymerization or after polymerization and before molding. In addition, the polyether ester block copolymer of the present invention includes hydrolysis resistance improvers, colorants (pigments, dyes), antistatic agents, conductive agents, flame retardants, reinforcing materials, fillers, lubricants, nucleating agents, and mold release agents. , a plasticizer, an adhesion aid, an adhesive, etc. can be optionally contained. The present invention will be explained below with reference to Examples. In the examples, all "parts" or "%" are expressed as weight ratios. Further, the logarithmic viscosity shown in the text and examples is a value measured in orthochlorophenol at 30°C and at a concentration of 0.5%. Example 1, Comparative Examples 1 and 2 1133 parts of dimethyl terephthalate, 2000 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of 2000 with a molecular weight distribution variance α = 1.50, and 307 parts of 1,4-butanediol were mixed with titanium tetrabutoxide. The mixture was charged together with 1.2 parts of the catalyst into a reaction vessel equipped with a helical ribbon stirring blade, and heated at 210°C for 2 hours to distill 95% of the theoretical amount of methanol out of the system. After adding 6.6 parts of “Irganox” 1010 to the reaction mixture, the temperature was raised to 245°C.
Next, the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out under these conditions for 4 hours and 20 minutes, yielding a transparent viscous polymer. Approximately 3 in the water
It was discharged as mmφ guts, cut through a take-off machine, and made into pellets. This polyether ester (A) had a melting point of 191°C and a logarithmic viscosity of 1.50.
Guttu immediately turned white in water and was not sticky. A test piece was prepared from this polymer pellet by injection molding, and the physical properties shown in Table 1 were evaluated. Comparative Examples 1 and 2 The number average molecular weight is approximately 2000 and the molecular weight distribution variance value α is
Polybutylene terephthalate hard segment/ Two types of polyether ester block copolymers (B) and (C) were prepared for comparison by adjusting the copolymerization ratio of poly(tetramethylene oxide) glycol terephthalate soft segment. (B) was cured at low temperature and its elastic recovery was also significantly impaired. On the other hand (C)
There were problems with formability and high temperature properties.

[Table] Examples 2 and 3 and Comparative Examples 3 and 4 The number average molecular weight is approximately 2300, and the molecular weight distribution dispersion value is
Polybutylene terephthalate hard segment/poly(tetramethylene oxide) glycol terephthalate soft segment copolymerization ratio 25/ Four polyether esters of 75 were prepared. These four types of polyether esters showed equivalent mechanical properties at room temperature, but showed large differences in flexibility, particularly in rubbery elastic recovery properties, at low temperatures. The results are shown in Table 2. Note that all test pieces for evaluation were created by press molding.

【table】

Claims (1)

[Scope of Claims] 1 (1) At least among the short chain dicarboxylic acid components
a dicarboxylic acid component of which 90 mol% is terephthalic acid or its ester-forming derivative; and (2) at least 90 mol% of a short chain diol component.
(3) A short chain diol component which is 1,4-butanediol or its ester-forming derivative, and (3) a number average molecular weight as a long chain diol component.
A polyether ester block copolymer obtained by copolymerizing poly(tetramethylene oxide) glycol with a molecular weight distribution dispersion value α of 1300 to 3000 as shown by the following formula; Polyester elastomer characterized by copolymerizing 55 to 90% by weight of (methylene oxide) glycol units; molecular weight distribution dispersion value α=v/n≦1.60 (where n is the number average molecular weight determined by the terminal group determination method, v
is the viscosity average molecular weight defined by the following formula. v=anti log ₁₀ (0.493 _{log 10} μ+3.0646) where μ is the melt viscosity at 40° C. in poise. )