JP3508886B2 - Thermoplastic polyester elastomer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyester elastomer, and more particularly to a thermoplastic polyester elastomer having a very low tetrahydrofuran content in a polymer. It is suitable for various uses mainly. A polyester-polyether copolymer having an aromatic polyester as a hard segment and a polyalkylene glycol as a soft segment, that is, a polyester elastomer, is produced by dicarboxylic diester, glycol or the like. , And a polyalkylene glycol are first subjected to a transesterification reaction, followed by polycondensation. A transesterification polymerization method is known. In a polymer obtained by this transesterification method, a large amount of tetrahydrofuran (THF) remains, It has been considered a problem that the heat resistance of the polymer decreases. In addition, polyester elastomers produced by this transesterification polymerization method are problematic because the time required for polycondensation is long, the production cost is low, and the viscosity is greatly reduced during casting (polymer removal) after the completion of polycondensation. SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester elastomer which solves the above-mentioned drawbacks of the prior art, reduces the amount of residual THF in the polyester elastomer, and has excellent heat resistance. It is in. That is, the present invention relates to a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid,
-A polyester elastomer obtained from a glycol component having a molecular weight of less than 250 mainly composed of butanediol and polytetramethylene glycol (PTMG) having a molecular weight of 400 to 6000, wherein the phosphoric acid content in the PTMG is 5 to 20 ppm and fluorine is contained. A thermoplastic polyester elastomer having a content of 100 ppm or less and a THF content (A) contained in the elastomer satisfying a relationship represented by the following formula (1). A / 20 <C / B (1) A: Tetrahydrofuran content in elastomer (pp
m) B: Content of phosphoric acid in polytetramethylene glycol (ppm) C: Content of polytetramethylene glycol in the elastomer (% by weight) The polytetramethylene glycol in the present invention has a molecular weight of 400. It may be a copolymer in which other components are copolymerized with polytetramethylene glycol in some cases. [0006] If the molecular weight of polytetramethylene glycol is less than 400, the resulting polyester elastomer will have poor blocking properties, and the melting point and softening point of the polymer will be low. Further, when the molecular weight exceeds 6,000, there is a problem that the copolymer undergoes phase separation and becomes opaque and pearl-like. [0007] Polytetramethylene glycol is generally produced using a fluorine compound such as fluorosulfonic acid as a catalyst, and a fluorine-containing compound resulting from these catalysts tends to remain. For this reason, generally commercially available polytetramethylene glycols often contain a fluorine compound far exceeding 100 ppm. On the contrary,
In the present invention, the fluorine content in polytetramethylene glycol is 100 ppm or less, preferably about 50 pp.
m, more preferably about 20 ppm or less. At this time, if a polytetramethylene glycol having a fluorine content exceeding 100 ppm is used, only a polymer having a low heat resistance can be obtained even by a transesterification polymerization method, and there are drawbacks such as foaming and a decrease in viscosity during casting. The polytetramethylene glycol having a fluorine content of 100 ppm or less can be obtained, for example, by a method using a non-fluorine-based strong acid catalyst (eg, perchloric acid or the like), or a polymerization reaction when using a fluorine-based strong acid catalyst. After completion, it can be obtained by a method of sufficiently washing with an alkaline aqueous solvent to remove fluorine-based impurities. Further, the polytetramethylene glycol of the present invention has a phosphoric acid content of 6 to 20 ppm, preferably 10 to 15 ppm, in addition to the above-mentioned fluorine content. At this time, when polytetramethylene glycol having a phosphoric acid content of less than 6 ppm is used, the reduction of the residual THF amount is extremely small,
If m exceeds m, the amount of residual THF is greatly reduced, but the color tone of the polymer deteriorates. The polytetramethylene glycol in the present invention may be added with phosphoric acid after polymerization by using a stirrer such as a tumbler-Henschel mixer. Further, when polymerizing the polyester elastomer, phosphoric acid and conventional polytetramethylene glycol may be added separately or simultaneously. The dicarboxylic acid component in the present invention is mainly composed of an aromatic dicarboxylic acid component.
0 mol% or more is an aromatic dicarboxylic acid or a diester thereof, and the aromatic dicarboxylic acid is terephthalic acid,
Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,
5-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid, diphenyl-
p, p-dicarboxylic acid and the like. In particular, terephthalic acid,
Isophthalic acid and 2,6-naphthalenedicarboxylic acid are preferably used. Further, succinic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,4
-Cyclohexanedicarboxylic acid. Isoaliphatic dicarboxylic acids can be used at less than 50 mol%. Further, the glycol used in the present invention is:
Preferably, it is a glycol containing 1,4-butanediol at 70 mol% or more and having a molecular weight of less than 250, such as ethylene glycol, 1,3-propanediol, 1,6.
A diol compound such as -hexanediol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol or the like may be used in combination of less than 30 mol%. The molar ratio of glycol to the acid component consisting of dicarboxylic acid or diester thereof is preferably 1.2 or more and 2.2 or less. In particular, it is preferably from 1.4 to 2.0. The weight percentage of the block repeating unit composed of polytetramethylene glycol and a dicarboxylic acid component, that is, the soft segment unit, based on the produced polyester elastomer can be selected according to the required elastic properties. About 80% by weight, especially 5
About 70% by weight is preferable. As a catalyst common to the transesterification reaction and the polycondensation, a titanium catalyst is preferred. Particularly, tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate, and metal oxalates such as potassium potassium oxalate are preferable. Examples of other catalysts include tin compounds such as dibutyltin oxide and dibutyltin dilaurate, and lead compounds such as lead acetate. The polyester elastomer may contain known stabilizers (for example, heat stabilizers, light stabilizers, etc.). Examples of the heat stabilizer include phenol compounds such as 4,4-bis (2,6-di-tert-butylphenol) and N, N′-bis (β-naphthyl)-.
Examples thereof include amine compounds such as p-phenylenediamine and sulfur compounds such as dilauryl thionate.
As the light stabilizer, for example, substituted benzophenone,
Benzotriazole compounds and the like can be mentioned. The polyester elastomer thus obtained has good polymer color tone without deteriorating the heat resistance, which is a characteristic feature of the polymer produced by the conventional transesterification polymerization method, and has the conventional transesterification polymerization method. It is more productive and more advantageous in terms of manufacturing cost. Hereinafter, the present invention will be described in detail with reference to examples. The properties of the polymer (elastomer) in this example were measured by the following method. In the examples, "parts" means parts by weight. (1) 20 mg of reduced viscosity polymer was mixed with 10 ml of a mixed solvent (phenol /
Tetrachloroethane = 60/40 weight ratio) and measured at 30 ° C. using an Ostwald viscometer. (2) L value (indicating lightness; the larger the value, the brighter) and the a value (the larger the value, the more reddish the color) using an automatic color difference meter (manufactured by Toyo Rika Kogyo Co., Ltd.) using a cylindrical chip sample of polymer color tone. Large) and b value (the larger the value, the greater the yellowishness). (3) THF content in polymer 10 ml of DMF and 5 μl of n-propyl acetate were added to 10 g of a sample, eluted with heating at 60 ° C. for 6 hours, allowed to cool, and then the amount of THF was quantified by gas chromatography. (4) The heat-resistant polymer was melted at 250 ° C. in an air atmosphere, and the time (minute) until foaming started was measured. Examples 1-5, Comparative Examples 1-5 48.4 parts of dimethyl terephthalate were placed in a reactor equipped with a rectification column.
49.5 parts of polytetramethylene glycol (fluorine content and phosphoric acid content are described in Table 1), 33.8 parts of 1,4-butanediol, 0.1 part of tetrabutyl titanate, Irganox 1330 (Nippon Ciba Geigy ( Co., Ltd.)
0.20 parts were charged and transesterification was carried out at an internal temperature of 130 ° C. to 225 ° C. until 90% of the theoretical amount of methanol had flowed out. The obtained reaction product was transferred to a polymerization reactor, and 240
The polycondensation reaction was carried out at a temperature of ° C. and in a high vacuum up to 2 torr. The reduced viscosity of the obtained polymer is 2.0 (g / d
l). As a result of NMR analysis, the weight% of the soft segment unit composed of the polytetramethylene glycol component and the like was 50% with respect to the polymer. The properties of the obtained polymer, the amount of residual THF in the polymer and the heat resistance of the polymer are shown in Table 1. As shown by these results, Examples 1 to 4 using a polytetramethylene glycol having a fluorine content of 100 ppm or less and a phosphoric acid content of 5 to 20 ppm as a raw material.
The resulting polymer No. 5 has a low THF content and good heat resistance. On the other hand, the polymer produced in Comparative Examples 1 and 4 in which the phosphoric acid content in polytetramethylene glycol does not exceed 5 ppm (including 0 ppm) has a large amount of residual THF, and has a problem in heat resistance. Further, the produced polymer of Comparative Example 5 in which the phosphoric acid content in polytetramethylene glycol exceeds 20 ppm has a poor polymer color tone. Furthermore, the produced polymers of Comparative Examples 1 to 3 using polytetramethylene glycol having a fluorine content exceeding 100 ppm have poor heat resistance (the time until foaming starts is short). [Table 1] Examples 6-9, Comparative Examples 6-9 50.6 parts of dimethyl terephthalate were placed in a reactor equipped with a rectification column.
19.2 parts of polytetramethylene glycol (fluorine content and phosphoric acid content are described in Table 2), 39.5 parts of 1,4-butanediol, 0.1 part of tetrabutyl titanate, Irganox 1330 (Nippon Ciba Geigy ( Co., Ltd.)
0.20 parts were charged and transesterification was carried out at an internal temperature of 130 ° C. to 225 ° C. until 90% of the theoretical amount of methanol had flowed out. The obtained reaction product was transferred to a polymerization reactor, and 240
The polycondensation reaction was performed at a temperature of ° C. and in a high vacuum state of up to 2 torr for 2 hours. The reduced viscosity of the obtained polymer is 1.40.
(G / dl). As a result of NMR analysis, the weight% of the soft segment unit composed of the polytetramethylene glycol component and the like was 25% with respect to the polymer. Table 2 shows the properties of the obtained polymer, the amount of residual THF in the polymer, and the heat resistance of the polymer. Example 6 similar to the example of Table 1 using polytetramethylene glycol having a fluorine content of 100 ppm or less and a phosphoric acid content of 5 to 20 ppm as a raw material.
The resulting polymers of Nos. To 9 have a low THF content and good heat resistance. When polytetramethylene glycol having a fluorine content of more than 100 ppm is used, the resulting polymer has poor heat resistance (the time until foaming starts is short). [Table 2] The thermoplastic polyester elastomer of the present invention has a low content of THF, has excellent heat resistance and good color tone, and is required to have heat resistance for automobiles, home electric parts and the like. Useful for applications.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (1)

(57) Claims 1. A dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid, a glycol component mainly composed of 1,4-butanediol having a molecular weight of less than 250, and a molecular weight of 400 to 60.
And a polytetramethylene glycol having a phosphoric acid content of 5 to 20 ppm and a fluorine content of 100 ppm or less in the polytetramethylene glycol. A) a thermoplastic polyester elastomer, wherein A) satisfies the relationship represented by the following formula (1). A / 20 <C / B (1) A: Tetrahydrofuran content in elastomer (pp
m) B: Content of phosphoric acid in polytetramethylene glycol (ppm) C: Content of polytetramethylene glycol in the elastomer (% by weight)