JP3408400B2 - Polyester resin - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin, and more particularly, to a polyester resin having heat resistance and excellent elasticity. [0002] Polyester-polyether polyester elastomers represented by PBT-PTMG (polybutylene terephthalate-polytetramethylene glycol) have heat resistance which cannot be obtained with olefin type elastomers. It is used as an impact-resistant structural material in many other fields, including automotive applications. In addition, polyester-polyester elastomers have also been developed and are used for applications requiring higher heat resistance. However, in recent years, there has been an increasing demand for thermoplastic resins in fields requiring high heat resistance, which cannot be used with conventional thermoplastic resins, such as around an engine of an automobile, mainly for the purpose of reducing the weight of automobiles. For this reason, polyester elastomers are required to have even higher heat resistance. Incidentally, polyester-polyether,
As a means for increasing the heat resistance of polyester elastomers such as polyester-polyester, a method of reducing the amount of soft segments introduced into the resin or a method of introducing a hard and heat-resistant structural unit into the resin is generally used. Used. However, although the heat resistance of each of these methods is improved, on the contrary, the elasticity (elasticity) originally required is impaired, and as a result, it is difficult to obtain an elastomer having both heat resistance and elasticity. Was. Another drawback of the conventional polyester elastomer is that the ether bond contained in the polymer structure is susceptible to deterioration by thermal decomposition when used at a high temperature, and therefore has a very high durability especially for automobiles and the like. Could not be used for applications requiring SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester resin having high heat resistance and excellent elasticity and having high form stability even in a high temperature environment. Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, a specific amount of maleic acid or a derivative thereof, and a specific polytetramethylene glycol The present inventors have found that a polyester resin contained as a united component can achieve the above object, and have completed the present invention. That is, the present invention provides (a) an aromatic dicarboxylic acid component, (b) a maleic acid component, (c) an aliphatic glycol component, and (d) a number average molecular weight of 800 to 300.
0), wherein the component (b) is 0.2 mol% or more with respect to the total acid component, the component (c) is 1 to 90 mol% with respect to the total glycol component, ) Component is 3% of the total polyester resin amount
Up to 95% by weight;
As described above, the polyester resin has a flexural modulus of 2000 kgf / cm ² or less. DETAILED DESCRIPTION OF THE INVENTION The aromatic dicarboxylic acid (a) used in the present invention comprises terephthalic acid, isophthalic acid, 1,4
Or 2,6-naphthalenedicarboxylic acid, sodium isophthalate, dicarboxydiphenyl, dicarboxybenzophenone, bis (4-carboxyphenyl) ethane and their ester-forming derivatives. Examples of the ester-forming derivative include terephthalic acid, isophthalic acid, dialkyl esters and diaryl esters of 1,4- or 2,6-naphthalenedicarboxylic acid. These aromatic dicarboxylic acids or ester-forming derivatives thereof are used singly or in combination of two or more. However, in order to further increase the heat resistance of the resulting polyester resin, 2,6-naphthalenedicarboxylic acid or its derivative is used. It is preferable to use the dialkyl ester of 5 mol% or more based on all acid components. More preferably, it is in the range of 7 to 100 mol%. In the present invention, an aliphatic dicarboxylic acid such as glutaric acid, adipic acid, sebacic acid, oxalic acid or succinic acid or an ester-forming derivative thereof is added in an amount of 10 mol% to the total dicarboxylic acid component of the polyester resin. You may make it contain in the range of less than. The maleic acid (b) used in the present invention is a component that forms a crosslinked structure between polymer molecular chains in the course of polycondensation and increases the elasticity that can be exhibited by a three-dimensional matrix structure. The crosslinked structure between the polymer molecular chains with maleic acid not only enhances the expression of elasticity, but also has the property of apparently controlling the macromolecular motion at high temperature by its matrix structure, so that it has high heat resistance and high temperature. , It is possible to remarkably increase the morphological stability. The amount of maleic acid used is at least 0.2 mol% based on the total acid components, preferably
７０70 mol%. The amount used is 0.2 mol%
If it is less than 3, the crosslink density is low, and sufficient elasticity and morphological stability at high temperatures cannot be obtained. The aliphatic glycol (c) used in the present invention includes ethylene glycol, 1,3-propanediol, 1,4-butanediol, pentanediol, 1,6-hexanediol, cyclohexanedimethanol, Pentyl glycol, diethylene glycol, triethylene glycol, 2-methylpropanediol, and the like are included, but are not particularly limited as long as they can be used as a glycol component of the polyester resin. These may be used alone or in combination of two or more. The amount of the aliphatic glycol to be used is in the range of 1 to 90 mol% based on the total glycol component. -Butanediol is preferably used in the range of 1 to 90 mol% based on all glycol components. The polytetramethylene glycol (d) used in the present invention is a component that reduces the elastic modulus of the obtained polyester resin and imparts flexibility. The number average molecular weight of the polytetramethylene glycol used is 8
00 to 3000. When the number average molecular weight of the polytetramethylene glycol used is less than 800, the expression of elasticity is insufficient. On the other hand, when the number average molecular weight exceeds 3,000, the probability of binding to the polyester chain due to a decrease in the number of molecular chain terminals is reduced. , And remains in the resin as an unreacted product, so that the polyester resin intended in the present invention cannot be obtained. The amount of polytetramethylene glycol (d) used is 3 to 9 based on the total amount of the obtained polyester resin.
It is in the range of 5% by weight, preferably 40-90% by weight.
If the amount of polytetramethylene glycol used is less than 3% by weight, it is difficult to exhibit flexibility, while if the amount exceeds 95% by weight, the amount of unreacted material that does not bond to the polyester molecular chain increases. Bleed out at the time of use, or during use, and degrade the performance of the product. In the production of the polyester resin of the present invention, the above-mentioned polymerization components (a) to (d) are charged into a reactor,
The temperature is increased by heating to perform an esterification reaction or a transesterification reaction. At this time, an esterification catalyst or a transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, magnesium acetate, and manganese acetate, which is used in a normal esterification reaction or transesterification reaction, can be used as necessary. Next, water or alcohol generated by the reaction is removed according to a conventional method. Thereafter, a polymerization reaction is subsequently carried out. At this time, the polymerization is carried out while distilling and removing the diol component under a vacuum of 150 mmHg or less. In the polymerization, generally known polymerization catalysts such as titanium butoxide, dibutyltin oxide,
Tin acetate, zinc acetate, tin disulfide, antimony trioxide,
Germanium dioxide or the like can be used. Further, the polymerization temperature and the amount of the catalyst are not particularly limited, and may be arbitrarily set as needed. The polyester resin of the present invention preferably has a heat-resistant temperature of 90 ° C. or higher, more preferably 90 ° C.
~ 150 ° C and flexural modulus 2000kgf / cm
² or less, more preferably 500 to
It is 1500 kgf / cm ² . This is because the heat resistant temperature is 9
If the temperature is lower than 0 ° C., the heat resistance is not sufficient, and if the flexural modulus exceeds 2000 kgf / cm ² , the elasticity is poor, and it is difficult to obtain a molded article having excellent form stability under a high temperature environment. . The polyester resin of the present invention may contain additives such as a lubricant, a releasing agent, a stabilizer, a filler, a reinforcing agent, and a coloring agent, if necessary. Hereinafter, the present invention will be described in detail with reference to examples. The evaluation of the physical properties in Examples and Comparative Examples was performed using the following methods. (1) Heat resistance The heat resistance was measured in accordance with the weight deflection temperature test method A described in JIS K7207. (2) Flexural modulus The flexural modulus was measured at a deformation rate of 2 mm / min by the bending test method described in JIS K7203. The abbreviations in Tables 1 and 2 indicate the following compounds. DMT: dimethyl terephthalate TPA: dimethyl terephthalate DMNDC: dimethyl 2,6-naphthalenedicarboxylate NDC: 2,6-naphthalenedicarboxylic acid MA: maleic acid EG: ethylene glycol BDO: 1,4-butanediol PTMG: number average molecular weight 1000 Example 1 The amounts of dimethyl terephthalate (DMT), dimethyl 2,6-naphthalenedicarboxylate (DMNDC), maleic acid (MA), ethylene glycol (EG) and 61% by weight of polytetramethylene glycol (PT
MG: number average molecular weight 1000) was charged into a reactor equipped with a stirrer, and transesterification was performed at 260 ° C. for 3 hours. Next, the obtained reaction product is sent to a polycondensation reactor, and antimony trioxide is used as a polycondensation catalyst in an amount of 40 to the acid component.
0 ppm, and 100 ppm of trimethyl phosphate as a stabilizer, and 0.5 minute over 40 minutes in the reaction system.
The pressure was reduced to mmHg, the internal temperature was maintained at 285 ° C., and a condensation reaction was carried out for 3 hours while distilling volatile components to obtain a polyester resin. Next, the polyester resin was dried at 80 ° C. for 24 hours using a vacuum dryer, and then a test piece was prepared using a commonly used injection molding machine to evaluate physical properties. Table 2 shows the resin composition and the physical properties of the polyester resin. Examples 2 to 11 and Comparative Examples 1 to 3 A polyester resin was obtained in the same manner as in Example 1 except that the polymerization charge composition was changed as shown in Table 1. Hereinafter, in the same manner as in Example 1, the obtained polyester resin was evaluated. Table 2 shows the resin composition and the physical properties of the polyester resin. [Table 1] [Table 2] The polyester resin of the present invention having the above-described structure has excellent heat resistance and elasticity.
It exhibits high flexibility and excellent morphological stability even in a relatively high temperature use environment, and can be used in many other fields including automotive applications.

Claims (1)

(57) Claims 1. An aromatic dicarboxylic acid component, (b)
A maleic acid component, (c) an aliphatic glycol component, and (d) a polytetramethylene glycol component having a number average molecular weight of 800 to 3000, wherein the component (b) is 0.2 mol% or more based on the total acid component; Wherein the component (c) is 1 to 90 mol% based on all glycol components, and the component (d) is 3 to 95 wt% based on the total polyester resin amount, and has a heat resistance temperature of 90 ° C. or higher, A polyester resin having a flexural modulus of 2000 kgf / cm ² or less.