JP3361904B2 - Polyester block copolymer composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition of a specific polyester block copolymer and polybutylene terephthalate. [0002] It is well known that polyester elastomers are widely used as heat-resistant and chemical-resistant thermoplastic elastomers. Among the polyester elastomers, the present inventors have proposed a block copolymer having a soft segment of a polyester comprising an aromatic dicarboxylic acid and a long-chain diol as a polyester elastomer having excellent heat resistance. [0003] However, when this elastomer has a large amount of soft segments, as in the present invention, there is often a problem that crystallization is slow during melt molding and the molded product sticks. This is a major drawback in thermoplastic elastomers, which have the greatest characteristic of being useful as a material because of having melt moldability. [0004] The object of the present invention is to solve the problem that the crystallization is slow and the molded product is sticky even when the elastomer of the present invention is used. The physical property of the molded article is that it still has the inherent properties of this elastomer. [0005] The inventors of the present invention have conducted various studies for the purpose of improving defects due to slow crystallization and improving moldability. As a result, in the case of the elastomer of the present invention, polybutylene terephthalate was obtained. Has been found to improve such disadvantages and show physical properties that are almost the same as those obtained by increasing the amount of hard segments in the production stage of the elastomer, leading to the present invention. That is, according to the present invention, there is provided a hard segment containing terephthalic acid and tetramethylene glycol as main components comprising at least 60 mol% of polybutylene terephthalate per dicarboxylic acid component, an aromatic dicarboxylic acid and 5 carbon atoms. Terephthalic acid and tetramethylene glycol are dicarboxylic acids per 100 parts by weight of the polyester block copolymer (A) with 80 to 50% by weight of a soft segment comprising a polyester in which the long-chain diol is at least 60 mol% per dicarboxylic acid component. 60 mol% or more of polybutylene terephthalate (B) per acid component
It is a polyester block copolymer composition obtained by mixing 1 to 100 parts by weight. The polyester block copolymer (A) used in the present invention contains polybutylene terephthalate as a main component as its hard segment, but may also contain other aromatic dicarboxylic acids containing benzene or naphthalene rings other than terephthalic acid, such as carbon, An aliphatic dicarboxylic acid of the formulas 4 to 12,
Diols such as aliphatic diols having 2 to 12 carbon atoms other than tetramethylene glycol and alicyclic diols such as cyclohexane dimethanol may be copolymerized, and the copolymerization ratio is less than 40 mol% based on all dicarboxylic acids. Preferably it is less than 30 mol%. The lower the copolymerization ratio, the higher the melting point, which is preferable. However, copolymerization is also performed to increase flexibility. However, when the copolymerization ratio is increased, crystallization is difficult, and the moldability and the like are deteriorated. Although this copolymerization ratio is difficult to specify in the block copolymer of the present invention, it can be considered that the copolymerization ratio can be applied when the melting point of the crystal is 160 ° C. or higher, preferably 170 ° C. or higher. On the other hand, as a soft segment of the polyester block copolymer, a polyester mainly composed of an aromatic dicarboxylic acid and a long-chain diol having 5 to 12 carbon atoms is used. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acids. Particularly, non-linear dicarboxylic acids such as phthalic acid and isophthalic acid are preferably used. As the diol, an aliphatic diol having 5 to 12 carbon atoms is used, and specific examples thereof include hexamethylene glycol, decamethylene glycol, 3-methylpentanediol, and 2-methyloctamethylenediol. . As the soft segment, a polymer having a melting point of 100 ° C. or less, preferably 50 ° C. or less, or an amorphous material is selected as a polymer composed of units constituting the soft segment. The soft segment is mainly a polyester of an aromatic dicarboxylic acid and a long-chain diol, and may be a copolymer of an aliphatic or alicyclic dicarboxylic acid other than the aromatic dicarboxylic acid and a short-chain diol. However, this copolymerization ratio is preferably 40 mol% or less based on the dicarboxylic acid component. As the copolymerizable aliphatic dicarboxylic acid or alicyclic dicarboxylic acid which can be used herein, for example, a linear dicarboxylic acid having 4 to 12 carbon atoms, particularly 8 to 1 carbon atoms
And straight-chain diols having 2 to 4 carbon atoms, and diethylene glycol. As the polyoxytetramethylene glycol, those having a relatively low molecular weight of 1200 or less, preferably 1000 or less are used. In the polyester block copolymer of the present invention, the ratio by weight of the hard segment to the soft segment is 20 to 50:80 to 50, preferably 25 to 50: 7.
5 to 50. The ratio of these amounts is because when the hard segment of the obtained polyester block copolymer is larger than this, in particular, it has sufficient moldability without carrying out the present invention, and when the soft segment is large, the crystallinity is increased. This is because the performance becomes low and the performance as an elastomer becomes insufficient. The segment length of the soft segment and the hard segment of the polyester block copolymer is approximately 500 to 7000, preferably 800 to 5,000 in terms of molecular weight, but is not particularly limited. Although it is difficult to directly measure the segment length, for example, the composition of the polyester constituting the soft and hard components, the melting point of the polyester composed of the components constituting the hard segment, and the melting point of the obtained polyester block copolymer From these, it can be estimated using Flory's equation. The method for producing the polyester block copolymer of the present invention may be any method. For example, polyesters comprising the components constituting the hard segment and the soft segment are produced and melt-mixed to form the hard segment having the melting point. There is a method of lowering the temperature by 2 to 40 ° C. than that of polyester. Since the melting point varies depending on the mixing temperature and time, it is preferable that the catalyst be deactivated by adding a catalyst deactivator such as phosphorous oxyacid at the time when the desired melting point is reached. A method of adding a lactone, which is a monomer of the soft segment, to the molten state of the polyester of the hard segment to carry out ring-opening polymerization is also a commonly used method. As the polyester block copolymer of the present invention, those having an intrinsic viscosity of 0.6 or more, preferably 0.8 to 1.5, measured at 35 ° C. in orthochlorophenol can be used. If the intrinsic viscosity is lower than this, the strength is lowered, which is not preferable. On the other hand, as polybutylene terephthalate (B), which is another composition component of the present invention, polybutylene terephthalate itself or a copolymer thereof is used. The copolymer may be any copolymer which can be generally copolymerized with a polyester. Examples thereof include other aromatic dicarboxylic acids, aliphatic or alicyclic dicarboxylic acids, and diols. And oxycarboxylic acids, and a small amount of a polyfunctional compound may be copolymerized. For example, as an aromatic dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acids, aliphatic dicarboxylic acids and alicyclic dicarboxylic acids, for example, a linear dicarboxylic acid having 4 to 12 carbon atoms, Particularly, a linear dicarboxylic acid having 4 to 12 carbon atoms, cyclohexanedicarboxylic acid and the like can be mentioned. Examples of copolymerizable short-chain diols include linear aliphatic diols having 2 to 12 carbon atoms, diethylene glycol, and the like. Further, as the oxycarboxylic acid, oxycaprosan, p
-Oxybenzoic acid and the like. The polybutylene terephthalate or a copolymer thereof as a component of the composition of the present invention generally has an intrinsic viscosity of 0.5 or more, preferably 0.6 to 1.5. If the intrinsic viscosity is lower than this, not only is the effect of accelerating the crystallization of the present invention weak, but also disadvantages such as a decrease in the overall melt viscosity and little improvement in the elastic modulus are caused. Conversely, if it is high, the overall viscosity is undesirably increased. In the present invention, a composition is obtained by mixing the polyester block copolymer (A) and the polybutylene terephthalate (B). The mixing ratio is 1 to 100 parts, preferably 2 to 50 parts, of polybutylene terephthalate (B) per 100 parts of the polyester block copolymer (A). In the present invention, the polyester block copolymer (A) and the polybutylene terephthalate (B) in the above proportions are mixed. This mixing method is not particularly limited, but generally a melt mixing method is used. For example, a method of melt-kneading at a temperature equal to or higher than the melting points of both polymers using an extruder is used. Also, after mixing the chips, supply them to the injection molding machine,
It can be mixed simultaneously with molding. In the composition of the present invention, it is also important to prevent the polyester block copolymer (A) from reacting with the polybutylene terephthalate (B). For this purpose, the melt kneading temperature is set to 270 ° C. And, if necessary, adding a catalyst deactivator. As the quenching agent, for example, derivatives such as phosphoric acid and phosphorous acid, esters of low molecular weight alcohol, acidic salts such as sodium, and those in which a part of phenylphosphonic acid or the like is substituted with an organic group are used. These are preferably used in an amount of at least equimolar to a metal such as a titanium compound, a tin compound, a zinc compound, and a manganese compound of the catalyst. The polyester block copolymer composition used in the present invention comprises, in addition to the polyester block copolymer (A) and polybutylene terephthalate (B), stabilizers, reinforcing materials, pigments, dyes, twisting agents, nucleating agents. , A lubricant and other additives, and may be a mixture with another polymer. Examples of the other polymer include copolymers such as ethylene, (meth) acrylate, vinyl acetate, styrene, and acrylonitrile. The amount of these additives and polymer is not less than the effect, and is usually 0.01 to 50 parts by weight based on 100 parts by weight of the composition of the present invention. The present invention will be described in detail with reference to examples. In the examples, “parts” means “parts by weight”. Reference Example 1 Dimethyl isophthalate 175
Part, 23 parts of dimethyl sebacate and 140 parts of hexamethylene glycol are subjected to a transesterification reaction with a dibutyltin diacetate catalyst, and then polycondensed under reduced pressure to give an intrinsic viscosity of 1.06.
An amorphous polyester (A) having no endothermic peak due to melting of the crystal was obtained by the DSC method. An intrinsic viscosity of 0.98 was obtained by separately polycondensing this polyester.
Of polybutylene terephthalate (a) was dried, 107 parts were added, and the mixture was further reacted at 240 ° C. for 45 minutes. Then, 0.1 part of phenylphosphonic acid was added to stop the reaction. The polyester block copolymer was taken out and made into chips to be used as a raw material. The melting point of this chip was 190 ° C. and the intrinsic viscosity was 0.93. Reference Example 2 Dimethyl isophthalate 125
, 54 parts of dimethyl sebacate and 140 parts of hexamethylene glycol were subjected to a transesterification reaction with a dibutyltin diacetate catalyst, followed by polycondensation under reduced pressure to obtain a polyester having an intrinsic viscosity of 1.06. This polyester was blocked in the same manner as in Reference Example 1 and then formed into chips (polyester block copolymer). Reference Example 3 This is a polyester block copolymer having the same polybutylene terephthalate content as in Reference Example 1. A polyester block copolymer was obtained in the same manner as in Reference Example 1, except that the addition amount of polybutylene terephthalate was changed to 150 parts. This had a melting point of 218 ° C. and an intrinsic viscosity of 0.91. Example 1 100 parts of the polyester block copolymer of Reference Example 1, 20 parts of polybutylene terephthalate having an intrinsic viscosity of 0.93 and 0.2 part of montanic acid wax
The portion was dried at 120 ° C. for 3 hours, melt-extruded with an extruder having a cylinder temperature of 240 ° C., cooled, and formed into chips. Under the conditions of a cylinder temperature of 230 ° C. and a mold temperature of 80 ° C., a JIS No. 3 dumbbell test piece was injection-molded from this chip. The molding cycle was 40 seconds and could be molded automatically. The bending test and the tear test were similarly formed. The test results of tensile, bending, and tearing of the obtained molded article are as shown in the table. No adhesion was observed even after the tensile test pieces were piled up and put on a 1 kg weight for one day. Was. Comparative Example 1 In a similar manner to Example 1, 120 parts of the polyester block copolymer of Reference Example 3 was extruded together with 0.2 part of montanic acid wax. Table 1 shows the results of the same physical property and adhesiveness test of the molded article as in Example 1.
At the time of molding, it was difficult to automatically remove the molded product, and the molded product was semi-automatically removed manually. [Examples 2 to 3] The results of the same study as in Example 1 were carried out using the polyester block copolymers of Reference Examples 1, 2 and 3 and changing the type and amount of polybutylene terephthalate. 1 is shown. [Table 1] By carrying out the present invention, the hard segment containing terephthalic acid and tetramethylene glycol at 60 mol% or more per dicarboxylic acid component as a main component is composed of polybutylene terephthalate at 20 to 50% by weight.
Crystallization at the time of molding of a polyester block copolymer of an aromatic dicarboxylic acid and 80 to 50% by weight of a soft segment comprising a polyester in which a long-chain diol having 5 to 12 carbon atoms is 60 mol% or more per dicarboxylic acid component. Is promoted, and molding can be easily performed, and the inconvenience that the products adhere to each other even after molding can be prevented. Another advantage is that, using one kind of polyester block copolymer and changing the addition amount of polybutylene terephthalate, it has the same characteristics as polyester block copolymers of various hardness. There are also advantages that can be made into a composition. In this case, only one type may be manufactured with a large-sized polymerization facility, and one having various hardnesses can be adjusted later by blending polybutylene terephthalate. This is easy even if the same polyester block copolymer is used, but in the case of a block copolymer of polyoxytetramethylene glycol and polybutylene terephthalate, it can be easily mixed with polybutylene terephthalate as in the present invention. This is a surprising fact compared to the fact that a variety in hardness cannot be obtained.

Claims (1)

(57) [Claim 1] 20 to 50% by weight of a hard segment containing terephthalic acid and tetramethylene glycol as main components of polybutylene terephthalate in an amount of 60 mol% or more per dicarboxylic acid component, and aromatic dicarboxylic acid The acid and the long-chain diol having 5 to 12 carbon atoms are contained in the dicarboxylic acid component in an amount of 60.
Terephthalic acid and tetramethylene glycol are 60 mol% per 100 parts by weight of the polyester block copolymer (A) with 80 to 50 wt% of a soft segment composed of a polyester which is at least mol%.
A polyester block copolymer composition obtained by mixing 1 to 100 parts by weight of the above polybutylene terephthalate (B).