JPH0629362B2 - Polyester ester block copolymer molding composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a composition for molding a polyetherester block copolymer having excellent moldability and rubber properties.

<Prior Art> Blending a polyetherester block copolymer with a polyetherester block copolymer is disclosed in JP-B-55-24467 and JP-A-59-58051.
It is known from the publication.

<Problems to be solved by the invention> Polybutylene terephthalate as a main hard component,
Polyether ester block copolymers containing poly (tetramethylene oxide) glycol as a soft component are thermoplastic with excellent properties such as flexibility, elastic properties, mechanical strength, oil and chemical resistance, and heat resistance. It has come to be used in the fields of rubber and flexible plastics by taking advantage of the fact that it can be molded similarly to the processing technology of plastics.

This polyether stell block copolymer is expected to have a high solidification rate during molding due to the excellent crystallinity of polybutylene terephthalate, which constitutes the hard component, and the molding cycle can be set short, resulting in high molding productivity. To be done.

However, when small moldings such as sound deadening gears and packings of watches and thin-walled moldings are actually injection-molded, the flowability decreases due to the crystallization of the polybutylene terephthalate hard component, resulting in short shots and unfilled moldings. It has been pointed out that the problem is. As a method for solving this problem, a method of using a polyetherester block copolymer having a low degree of polymerization and a method of raising the molding temperature to reduce the melt viscosity of the polyetherester block copolymer are considered. When a polyether ester block copolymer having a low degree of polymerization is used, the rubber properties represented by bending fatigue of the obtained molded product are poor, and the polyether ester block copolymer is molded at a high molding temperature. In this case, the soft component of the poly (alkylene oxide) glycol is inferior in heat resistance, so that it is thermally decomposed to lower the degree of polymerization, and the rubber properties are similarly deteriorated. Further, the method of using a polyetherester block copolymer having a low degree of polymerization and the method of increasing the molding temperature have a problem that burrs are apt to be generated in a molded article.

The present invention solves the above problems and provides a molding composition in which the molding processability is improved in order to obtain an excellent molded product in a short molding cycle, and the resulting molded product has excellent rubber properties. With the goal.

JP-B-55-24467 discloses that a crystalline polyetherester block copolymer is blended with an amorphous polyetherester block copolymer to soften the crystalline polyetherester block copolymer. It is shown. In this composition, there is a problem that blending of an amorphous polymer lowers the solidification rate, prolongs the molding cycle, and easily causes burrs on the molded product. The blends of crystalline polyetherester block copolymers and crystalline polyetherester block copolymers of the present invention are different.

JP-A-59-58051 discloses a polyether ester block copolymer containing a large amount of poly (alkylene oxide) glycol component and a polyether ester block copolymer containing a small amount of poly (alkylene oxide) glycol component. A method is shown to blend the coalesce to improve tack, primarily when formed into fibers. The polyether ester block copolymer containing a large amount of poly (alkylene oxide) glycol component is
Since the block chain length of the hard component, polyalkylene terephthalate, is short, the polymer has extremely poor crystallinity, and when molding represented by injection molding is performed, the molding cycle is long and burrs occur in the molded product. Products with high commercial value cannot be obtained. Unlike the polyetherester block copolymers of the present invention which contain relatively small amounts of poly (alkylene oxide) glycol.

<Means for Solving the Problems> The object of the present invention is to contain X% by weight of poly (alkylene oxide) glycol as a soft component, and
Polyether ester block copolymer containing X wt% polybutylene terephthalate as a hard component
(A) and a polyether ester block copolymer (B) containing Y-wt% poly (alkylene oxide) glycol as a soft component and 100-Y wt-% polybutylene terephthalate as a hard component. , X and Y are in the range of 10 <X <60 10 <Y <60 2 ≦ | X−Y | ≦ 20, to provide a polyether tester block copolymer molding composition. Can be achieved.

The polyether ester block copolymers (A) and (B) used in the present invention have poly (alkylene oxide) glycol as a soft component and poly (butyle terephthalate) as a hard component.

As the poly (alkylene oxide) glycol constituting the soft component, polyethylene glycol, poly (1,
2- and 1,3-propylene oxide) glycol,
Poly (alkylene oxide) glycols such as poly (tetramethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, and copolymers of ethylene oxide and tetrahydrofuran are mentioned. Of these, particularly high temperature characteristics and elastic recovery are required. Poly (tetramethylene oxide) glycol is suitable for certain applications. The number average molecular weight of the poly (alkylene oxide) glycol is 300 to 6000, more preferably 500 to 45.
When the molecular weight is too large, the poly (alkylene oxide) glycol unit itself becomes crystalline, and the function of elastic recovery is lost, and the compatibility is deteriorated. On the contrary, when the molecular weight is 300 or less, the length of the polyester block which is a hard segment becomes too short, so that the elastic recovery property is lost in this case as well.

The contents X and Y of the poly (alkylene oxide) glycol contained in the polyether ester block copolymer may be in the range of 10 <X <60 10 <Y <60 (X, Y:% by weight). is necessary. When the values of X and Y are 10 or less, the obtained polyether ester block copolymer has poor rubber properties and cannot be used. When it is 60 or more, the crystallinity of the polyether ester block copolymer is low and the moldability is poor, so that it cannot be used.

As the polybutylene terephthalate constituting the hard component, the dicarboxylic acid component is terephthalic acid or an ester-forming derivative thereof, and the diol component is 1,
It consists of 4-butanediol, but is 30 mol%
If within, isophthalic acid, phthalic acid, naphthalene-
Aromatic dicarboxylic acids such as 2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid and sodium 3-sulfoisophthalate, 1,4 -Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanedioic acid, aliphatic dicarboxylic acids such as dimer acid, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol , Aliphatic diols such as neopentyl glycol, decamethylene glycol, 1,1-cyclohexanedimethanol, 1,4
Alicyclic diols such as cyclohexanedimethanol and tricyclodecanedimethanol, xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, 2,2-bis [4- (2
-Hydroxyethoxy) phenyl] propane, bis [4
Polybutylene terephthalate copolymerized with a diol containing an aromatic group such as-(2-hydroxy) phenyl] sulfone and 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane can also be used.

The polyether ester block copolymers (A) and (B) composed of the soft component and the hard component can be produced by a known method. For example, a method of subjecting a lower alcohol diester of terephthalic acid, an excess amount of 1,4-butanediol and poly (alkylene oxide) glycol to a transesterification reaction in the presence of a catalyst and polycondensing the obtained reaction product, or terephthalic acid and 1 , 4-butanediol and poly (alkylene oxide) glycol are allowed to react with ester in the presence of a catalyst to polycondense the obtained product, or polybutylene terephthalate is prepared in advance, and other dicarboxylic acid or diol or Any method may be used, such as a method of adding poly (alkylene oxide) glycol or a method of adding other copolymerized polyester and performing randomization by transesterification.

As a catalyst common to transesterification or esterification and polycondensation reactions, titanium catalysts give good results.
Particularly preferred are tetraalkyl titanates such as tetrabutyl titanate and tetraisopropyl titanate, and titanium oxalate metal salts such as potassium oxalate. Examples of other catalysts include tin compounds such as dibutyltin oxalate and dibutyltin laurate, and lead compounds such as lead acetate.

Further, a polycarboxylic acid, a polyfunctional hydroxy compound, an oxy acid or the like may be copolymerized as a part of terephthalic acid or 1,4-butanediol. The polyfunctional component effectively acts as a viscosity increasing component, and its copolymerizable range is 3
It is not more than mol%. Examples of such polyfunctional components that can be used include trimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, butanetetracarboxylic acid, glycerin, pentaerythritol and their esters, and acid anhydrides. it can.

The relative viscosity of the polyether ester in the present invention is at least 1.35 or more, preferably 1.40 or more.

Polyetherester block copolymer of the present invention (A)
It is important that the contents X and Y of the soft components in (B) and (B) are in the range of 2 ≦ | X−Y | ≦ 20 when forming a molding composition. When it is less than 2, the effect of improving the moldability when the composition is a molding composition is small, and when it is 20 or more, the compatibility of the (A) polymer and the (B) polymer is reduced, and a coarse phase separation structure is formed, resulting in rubber properties. Cannot be used because the molded product has a pearlescent luster. More preferably, 5 ≦ | X−Y | ≦ 15.

The composition of the present invention is usually one in which two types of polyether ester block copolymers are melt-mixed, but the melt-mixing method is not particularly limited. They may be mixed using an extruder, or two types of pellets may be dry blended, and injection and extrusion molding may be performed. In addition, the molding composition of the present invention contains other components as long as the object of the present invention is not impaired, such as pigments, dyes, flame retardants, heat resistance agents, antioxidants, weathering agents, lubricants, release agents, and electrostatic charges. Inhibitor, plasticizer,
It is possible to add crystal nucleating agents, foaming agents, reinforcing agents, fillers and other polymers.

<Examples> Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 [Polyether ester block copolymer] A predetermined amount of dimethyl terephthalate so as to have a polymer composition shown in Table 1, poly (tetramethyloxide) glycol having an average molecular weight of 1000, and 1,4-butanediol (based on dimethyl terephthalate). 1.5 times the molar amount) and 0.05% by weight of tetrabutyl titanate with respect to dimethyl terephthalate in a nitrogen atmosphere at 220 ° C. after distilling methanol by transesterification, and charging the resulting mixture in a polymerization vessel at 240 ° C. Polymerization was carried out by gradually reducing the pressure until the pressure reached 0.2 mmHg, and a discharge pellet was formed at a predetermined degree of polymerization. Table 1 shows the relative viscosity, melting point and crystallization temperature of the obtained polyetherester block copolymer.

Examples 2-5, Comparative Examples 1-10 Two kinds of the polyether ester block copolymers obtained in Example 1 were dry blended so as to have the composition shown in Table 2, and the injection capacity of 5-ounce was obtained. Using an injection molding machine having a temperature of 240 ° C and a mold temperature of 60 ° C.
A square plate having a size of × 100 × 1 mm was formed. At this time, the molding lower limit pressure was measured as a measure of the fluidity of the polymer, the molding cycle was observed as a measure of the solidification speed, and the burr length of the obtained molded product was measured.

A 25 × 100 × 1 mm test piece was cut out from this square plate, and the bending fatigue property was measured by the method described in JIS K6301.

The results are summarized in Table 2.

Comparative Example 11 According to the method described in Example 1, a polyether ester block copolymer (P-8) having a poly (tetramethylene oxide) glycol content of 60% by weight and a polyether ester block copolymer having a poly (tetramethylene oxide) glycol content of 75% by weight (P-9) were obtained. It was Table 3 shows the relative viscosities, melting points and crystallization temperatures of P-8 and P-9.

67 parts of P-8 and 33 parts of P-9 are used in Examples 2 to 5,
100 × 10 by injection molding under the same conditions as Comparative Examples 1-10
A 0 × 1 mm square plate was formed. The molding lower limit pressure at that time is 2
55 kgf / cm ² , the molding cycle was 118 seconds, the solidification rate was extremely slow, and the burr length of the obtained molded product was 16.2 mm, showing that the moldability was remarkably poor as compared with the polymers of the examples. .

<Effects of the Invention> From the examples, it is clear that the composition of the present invention is excellent in moldability and flex fatigue.

Claims (1)

[Claims] 1. 100% by weight of X-containing poly (alkylene oxide) glycol as a soft component.
A polyether ester block copolymer (A) containing polybutylene terephthalate as a hard component, and Y
And a polyether ester block copolymer (B) containing 100% by weight of poly (alkylene oxide) glycol as a soft component and 100-Y% by weight of polybutylene terephthalate as a hard component. <X <60 10 <Y <60 2 ≦ | X−Y | ≦ 20 A composition for molding a polyetherester block copolymer, characterized in that: