JPS5921890B2 - Polybutylene terephthalate resin molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polybutylene terephthalate resin molded articles having excellent mechanical properties.

In recent years, polybutylene terephthalate has attracted attention as an engineering plastic with excellent moldability and well-balanced mechanical strength.

In order to produce polybutylene terephthalate 10-ml, which is generally used for molding applications such as fibers, films, injection, extrusion, and sheets, terephthalic acid and 1|4-butanediol are esterified and bis-(δ- (hydroxybutyl) terephthalate and its low polymers, and such products are heated at high temperature (approximately 250°C) and high vacuum (O, 5 mmHg or less).
A direct esterification method in which polymerization 15 is carried out under the conditions of It is usually produced by either the transesterification method, in which polymerization is carried out under high temperature and high vacuum conditions, similar to the above-mentioned direct esterification method. Examples of catalysts for the above-mentioned esterification reactions, transesterification reactions, and polymerization reactions include those disclosed in JP-A-50-24389 and JP-A-50-2439025.
No. 1, JP-A No. 50-34394, and JP-A-Sho 5
It is known that titanate alkyl ester compounds and organic tin compounds are effective, as described in Japanese Patent No. 0-38791 and the like.

However, titanate alkyl ester compound 30 has a drawback that it is highly reactive with water, and when it comes into contact with water, it instantly turns into a muddy white compound and loses its catalytic activity. When producing polybutylene terephthalate by the direct esterification method using 35, the catalyst is likely to be deactivated by the moisture in the raw material butanediol and the esterification reaction water. Therefore, unreacted terephthalic acid, dimethyl terephthalate, oligomers thereof, and reaction products of titanate alkyl ester and water are present in polybutylene terephthalate produced using an alkyl titanate compound as a catalyst. The mechanical properties of the polymer are not satisfactory since they are dispersed as foreign matter.

In addition, by melt polymerization using ordinary titanate alkyl ester compounds and organic tin compounds as catalysts, the relative viscosity t
) Sl. When producing polybutylene terephthalate of 49 or more, the polymerization degree of the polymerization system competes with the thermal decomposition reaction, so the degree of polymerization reaches a plateau, and it may not be possible to obtain a polymer with the desired degree of polymerization, or even if it is not obtained. Even if it were possible, the polymer would have a large number of carboxyl terminal groups, have poor heat resistance and weather resistance, and have extremely low commercial value.

Polybutylene terephthalate, which has a large number of terminal carboxyl groups, not only does not have a high degree of polymerization, but also tends to have a lower molecular weight due to the terminal carboxyl groups when melted to form a molded product, and inevitably deteriorates mechanical properties. Therefore, the present inventors conducted intensive studies to obtain polybutylene terephthalate that retains excellent catalytic activity and has excellent mechanical properties even under melt polymerization conditions where trace amounts of moisture are present. By using titanate glycol ester obtained by reacting an alkyl ester compound with a specific alkylene glycol as a catalyst for esterification reaction, transesterification reaction, and polymerization reaction,
In particular, it has excellent mechanical properties even with a lower degree of polymerization than before.
It has been discovered that polybutylene terephthalate S suitable for molding applications can be obtained, and furthermore, when a specific sulfonic acid metal salt compound is used together with the titanate glycol ester as a polymerization catalyst, a high degree of polymerization can be achieved under a shortened polymerization time. It has been found that polybutylene terephthalate can be obtained, and polybutylene terephthalate resin molded products with excellent mechanical properties, heat resistance, weather resistance, and color tone can be obtained.

That is, the present invention mainly consists of an acid component mainly consisting of terephthalic acid or (lower) dialkyl terephthalate, and an acid component mainly consisting of 1,
A diol component consisting of 4-butanediol is esterified with glyco-fulster titanate, which is a reaction product of alkyl titanate and 1,4-butanediol and/or 1,6-hexanediol, or a transesterification catalyst and /Or polymerization using an alkali metal or alkaline earth metal salt compound of an aromatic sulfonic acid having at least one ester-forming functional group as a polymerization catalyst and molding the obtained polybutylene terephthalate. The present invention provides a method for manufacturing a polybutylene terephthalate resin molded product characterized by the following.

Polybutylene terephthalate obtained using a normal titanate alkyl ester compound as a catalyst has a strain rate of 50%,
Relative viscosity is at least 1 to exhibit tensile elongation at break of 200%
．． A polymerization degree of 61 or higher is required, but surprisingly, the polybutylene terephthalate produced using the titanate glycol ester of the present invention as a catalyst has a relative viscosity of 1.54.
The above tensile elongation at break is 200%.

The reason for this is that the reaction product of titanate alkyl ester and alkylene glycol has high catalytic activity in esterification reactions, transesterification reactions, and polymerization reactions, and can be effectively used without deactivation even in the presence of trace amounts of moisture. This is thought to be due to the fact that the bis-(δ-hydroxybutyl) terephthalate produced in the esterification reaction and transesterification reaction is highly homogeneous, and there is little unreacted terephthalic acid or lower alkyl terephthalic acid ester.

Therefore, the mechanical properties of a polymer polymerized from such bis-(δ-hydroxylbutyl) terephthalate are excellent as described above, and are suitable as a molding resin. The polybutylene terephthalate used to form the molded product of the present invention refers to a polyester whose main components are terephthalic acid and 1,4-butanediol, and up to 50 mol% of the acidic or diol component is phthalic acid, isophthalic acid, Succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, hexahydroterephthalic acid, 2,6-naphthalene dicarboxylic acid, 2,5-dibromoterephthalic acid,
Acids such as diphenyl dicarboxylic acid, trimellitic acid, trimesic acid, pyromellitic acid and ethylene glycol, propylene glycol, diethylene glycol, polytetramethylene glycol, polyethylene glycol,
1,6-hexanediol, trimethylene glycol,
Neopentyl glycol, p-xylylene glycol,
Also included are polyesters substituted with alcohols such as 1,4-cyclohexanedimethanol, bisphenol A1 glycerin, pentaerythritol, trimethanolpropane, trimethanolbenzene, and triethanolbenzene.

The titanate glycol ester used as a catalyst in the present invention is obtained by reacting a titanate alkyl ester compound represented by the general formula Ti(0R)4 (R is an alkyl group having 1 to 10 carbon atoms) with an alkylene glycol. Specifically, titanate alkyl esters such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, isobutyl titanate, and 1,4-butanediol. and/or a reaction product with 1,6-hexanediol, particularly a reaction product of tetraisopropyl titanate or tetra-n-butyl titanate with 1,4-butanediol or 1,6-hexanediol. It is.

As a specific method for synthesizing these titanate glycol esters, a method is adopted in which a titanate alkyl ester and an alkylene glycol are heated and reacted, and the alcohol is distilled off through a transesterification reaction to obtain a product. At this time, a distillate obtained by distilling 20% or more of the theoretical distillate amount can be used as a catalyst, but it is particularly preferable to use a product which has undergone transesterification of 50% or more. The amount of this titanate glycol ester catalyst used is 0.0005 to 1 mole based on the acid component of polybutylene terephthalate. , particularly preferably 0.025 to 0.2 mol %, and is suitably added before esterification reaction, before transesterification reaction, and before polymerization reaction. Furthermore, even when this titanate glycol ester catalyst is used in combination with other known catalysts, its effects are not impaired in any way.

For example, even if other organotin catalysts are used in combination for the purpose of reducing tetrahydrofuran as a by-product during the production of polybutylene terephthalate, the effect of improving the physical properties of the titanate glycol ester catalyst is not impaired. However, in the present invention, it is not preferable to coexist a pentavalent antimony compound during polymerization because it not only has no effect at all, but also increases the number of terminal carboxyl groups. Examples of the alkali metal or alkaline earth metal salt compounds of aromatic sulfonic acids having at least one ester-forming functional group used in the present invention include sodium carboxybenzenesulfonate, potassium carboxybenzenesulfonate,
Sodium 3,5-di(carboxy)benzenesulfonate, calcium 3,5-di(carboxy)benzenesulfonate and their methyl alcohol, ethyl alcohol, phenol, ethylene glycol, 1,4-butanediol, 1,2- Typical examples include esters such as propanediol and 1,6-hexanediol.

The sulfonic acid metal salt compound can be added at any stage during the production of polybutylene terephthalate, such as during the esterification reaction, transesterification reaction, or polymerization reaction, and most preferably immediately before the melt polymerization reaction or before the melt polymerization reaction. The reaction is in progress. The amount of the sulfonic acid metal salt compound added is 5 mol% or less, preferably 0.05 mol% to 2 mol%, based on the acid component. When polybutylene terephthalate with a relative viscosity of 1.49 or more is produced by a normal melt polymerization method, the degree of polymerization peaks out as described above, so it is difficult to obtain a polymer with the desired degree of polymerization. In order to obtain the desired polymer with a high degree of polymerization, it is necessary to increase the amount of catalyst, which not only reduces the color stability of the polymer during melting, but also has a large number of terminal carboxyl groups, resulting in poor heat resistance and weather resistance, resulting in low commercial value. Only molded products can be obtained. However, according to the second aspect of the present invention, in which melt polymerization is carried out in the presence of a sulfonic acid metal salt compound together with titanate glycol ester, a polymer having a relative viscosity of 1.49 or more can be easily produced due to the rapid polymerization effect of the sulfonic acid metal salt compound. It is possible to obtain polybutylene terephthalate resin molded products with a small number of terminal carboxyl groups and excellent mechanical properties, color tone, heat resistance, and weather resistance. The appropriate melt polymerization temperature for the present invention is usually 250°C, and the desired degree of polymerization and mechanical properties can be obtained in 2 hours of polymerization.

If polybutylene terephthalate with a high relative viscosity is desired, the degree of polymerization can be increased by performing melt polymerization until the relative viscosity reaches about 1.40 and then performing solid phase polymerization. The polybutylene terephthalate resin thus obtained is molded by a conventional method.

For example, when molding a rectangular plate with a length of 22 (V7!, width 2C!!L1, and thickness of 3 mm) using an injection molding machine with an injection molding capacity of 5 ounces, an ordinary titanate alkyl ester compound is used as a catalyst. Polybutylene terephthalate, which had a relative viscosity of 1.62, has a high melt viscosity and cannot be molded into a complete molded product unless the injection pressure is 24 vs/Cd or higher.

On the other hand, when polybutylene terephthalate using the titanate glycol ester of the present invention as a catalyst is similarly molded, a sufficient molded product can be obtained with an injection pressure of 13 kg/CdO. Furthermore, the mechanical properties of the molded products are exactly the same when compared in terms of the tensile elongation at break, which is 210% and 220%, respectively. From the above, the polybutylene terephthalate used in the present invention has good flow.
A molded product with significantly improved moldability and excellent mechanical properties can be obtained. In addition, other thermoplastic resins such as styrene resins and polyolefin resins may be blended with the polybutylene terephthalate of the present invention during melt polymerization or at other stages in order to further improve various physical properties such as impact resistance. and aromatic halogen compounds and nonflammable polymer compounds to make the polymer flame retardant.
It is possible to incorporate known flame retardants and flame retardant aids such as antimony trioxide, as well as inorganic fillers such as glass fiber, asbestos, calcium metasilicate, and potassium titanate, and nucleating agents and lubricants such as talc. , a heat stabilizer, an anti-static agent, and other various additives may be optionally added.

In the present invention, the relative viscosity refers to orthochlorophenol (0
CP) as a solvent and a 0.5% polymer solution was measured at 25°C. In addition, the intrinsic viscosity is a divisor obtained by dividing the natural logarithm value of the relative viscosity by the polymer concentration (=0.5). The present invention will be specifically explained below with reference to Examples.

Example 1 85V of tetra-n-butyl titanate and 850Y of 1,4-butanediol were charged into a Mitsuro flask equipped with a fractionator, and the temperature was gradually raised to 200°C while stirring.
After reacting for about 1 hour, 70y of n-butanol was distilled out.

This reaction product is designated as catalyst A. Terephthalic acid 85kg
and 1,4-butanediol 90 and the catalyst shown in Table 1 were charged into an esterification vessel equipped with a rectification column, and reacted at 160 to 210°C for 3 hours and 30 minutes at normal pressure,
The reaction was completed by continuously distilling off the distillate.

This reaction product was transferred to a polymerization reactor, each of the catalysts shown in Table 1 was added thereto, and 2
The intrinsic viscosity at 50°C is 0.877 to 0.889 (
Polymerization was carried out for a time until the relative viscosity reached 1.55-1.56). The measurement results of the melt polymerization time, intrinsic viscosity (relative viscosity), number of terminal carboxyl groups, softening point, tensile elongation at break, tensile impact strength and polymer color tone before and after the 13 month heat resistance test of each of the obtained polymers were summarized in the second table. Shown in the table.

As is clear from Table 2, the catalyst system of the present invention has a shorter polymerization time than when conventional tetrabutyl titanate is used, has fewer terminal carboxyl groups, and has improved mechanical properties, heat resistance, and color tone. A polybutylene terephthalate resin molded product with excellent properties can be obtained.

Example 2 Dimethyl terephthalate 9 instead of terephthalic acid 85 snake
The transesterification reaction and polymerization reaction were carried out in the same manner as in Example 1, except for using a 9-carboxylic resin.
106y polybutylene terephthalate was obtained.

Comparative Example 3 A catalyst prepared by adding antimony pentoxide 12y (Sb/Ti atomic ratio = 1/1) to Catalyst A as a catalyst added before melt polymerization in Example 1 and 3,5-dicarbomethoxy)
A polymerization reaction was carried out in the same manner as in Example 1 except for using sodium benzenesulfonate, and the intrinsic viscosity was 0.687 (
Polybutylene terephthalate having a relative viscosity of 1.41) and a number of terminal carboxyl groups of 6.18 equivalents/1067 was obtained.

Claims (1)

[Claims] 1 Reaction of an acid component mainly consisting of terephthalic acid or (lower) dialkyl and a diol component consisting of 1,4-butanediol with an alkyl titanate ester and 1,4-hexanediol and/or 1,6-hexanediol The product glycol titanate is used as an esterification or transesterification catalyst and/or a polymerization catalyst, and an alkali metal or alkaline earth metal salt compound of an aromatic sulfonic acid having at least one ester-forming functional group is used as a polymerization catalyst. 1. A method for producing a polybutylene terephthalate resin molded product, which comprises polymerizing the polybutylene terephthalate using a polybutylene terephthalate resin and molding the obtained polybutylene terephthalate.