JPH11256014A - Polyester blockcopolymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an elastomer compsn. formable to a molded article with heat resistance and high transparency, moreover easy to adjust the flexibility, by blending a polyester blockcopolymer composed of a hard segment and a soft segment, a polybutylene terephthalate, an organic carboxylic acid sodium salt, etc. SOLUTION: A compsn. comprises a melt blend: 100 pts.wt. of a polyester blockcopolymer composed of 20-70 wt.% of a hard segment with the main component of a polybutylene terephthalate in which terephthalic acid and tetramethylene glycol are of 60 mole % or more relative to dicarboxylic acid component and 80-30 wt.% of a soft segment of a polyester in which an aromatic dicarboxylic acid and a long-chain diol of HO(CH2 CH2 O)1 H (wherein i is 2-5) are of 60 mole % or more relative to dicarboxylic acid component; 0-200 pts.wt. of a polybutylene terephthalate; and 0.5-10 pts.wt. of at least one kind compd. selected from a sodium salt of an organic carboxylic acid having the number of carbons of 7-40 and a sodium salt of an organic phosphoric partial ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester elastomer composition having heat resistance and high transparency.

[0002]

It is well known that polyester elastomers are widely used as heat-resistant and chemical-resistant thermoplastic elastomers. Among them, those using polytetramethylene glycol as the soft segment may still have insufficient heat resistance, chemical resistance, and the like. As a countermeasure, the present inventors have previously proposed a polyester block copolymer having a soft polyester as a soft segment and having excellent heat resistance and chemical resistance (JP-A-4-153216). Especially as a soft segment,
A polyester block copolymer using a polyester of terephthalic acid and an ether glycol such as triethylene glycol is a preferable polyester block copolymer having a high crystallization rate and good heat resistance and chemical resistance.

[0003] A polyester block copolymer using a polyester comprising terephthalic acid and triethylene glycol or the like shows a nearly transparent state in a molten state. However, even if this polymer is quenched and molded, only rapid crystallization and an opaque molded product can be obtained.

[0004] On the other hand, depending on the application, a transparent and flexible molded product having high heat resistance is required, for example, when it is necessary to view light or a picture later through the molded product. Such heat resistance,
There has been a demand for a composition having transparency in addition to flexibility and capable of controlling flexibility.

[0005]

An object of the present invention is to provide a polyester elastomer composition which can be formed into a molded article having high transparency, and furthermore, the flexibility of the composition can be easily adjusted by changing the composition ratio of the composition. It is to obtain a polyester elastomer composition that can be used.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have repeatedly studied to find a polyester elastomer composition having the above-mentioned excellent properties, and as a result, it has been found that a specific polyester block copolymer has compatibility with polybutylene terephthalate. The present invention has been found to be almost transparent at the time of melting, and to be transparent when a sodium carboxylate or the like is further added thereto.

That is, according to the present invention, (A) terephthalic acid and tetramethylene glycol are used in an amount of 60 per dicarboxylic acid component.
20 to 70% by weight of a hard segment containing at least mol% of polybutylene terephthalate as a main component, an aromatic dicarboxylic acid and HO (CH ₂ CH ₂ O) _i H (i = 2 to 2)
5) Soft segment 8 comprising a polyester in which the long-chain diol is at least 60 mol% per dicarboxylic acid component.
Polyester block copolymer 10 with 0 to 30% by weight
0 parts, (B) polybutylene terephthalate 0 to 200
(C) a polyester block copolymer composition comprising 0.5 to 10 parts by weight of at least one selected from the group consisting of sodium salts of organic carboxylic acids having 7 to 40 carbon atoms and sodium salts of organic phosphoric acid partial esters. .

In the polyester block copolymer used in the present invention, the hard segment is mainly composed of polybutylene terephthalate, but in addition to terephthalic acid, an aromatic dicarboxylic acid containing a benzene or naphthalene ring, and having 4 to 4 carbon atoms. 12 aliphatic dicarboxylic acids, aliphatic diols having 2 to 12 carbon atoms other than tetramethylene glycol, and diols such as cycloaliphatic diols such as cyclohexanedimethanol may be copolymerized. Less than 40 mol%, preferably less than 30 mol%, per dicarboxylic acid. 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. This copolymerization ratio is difficult to specify in the block copolymer of the present invention, but the melting point of the crystal is 15%.
A copolymerization ratio of 0 ° C. or higher, preferably 160 ° C. or higher is preferable.

On the other hand, as the soft segment, a polyester mainly composed of terephthalic acid and a long-chain diol of HO (CH ₂ CH ₂ O) _i H (i = 2 to 5) is used. An aromatic dicarboxylic acid other than an acid, an aliphatic or alicyclic dicarboxylic acid, or a copolymer of a short-chain diol may be used. This copolymerization ratio is less than 40 mol%, preferably less than 30 mol%, based on the dicarboxylic acid component.

The copolymerizable aromatic dicarboxylic acid, aliphatic dicarboxylic acid and alicyclic dicarboxylic acid which can be used herein include, for example, isophthalic acid, phthalic acid, naphthalenedicarboxylic acids, linear C 4-12 Dicarboxylic acids, especially linear dicarboxylic acids having 8 to 12 carbon atoms, cyclohexanedicarboxylic acids, and the like. Examples of copolymerizable short-chain diols include linear aliphatic diols having 2 to 12 carbon atoms. Is done. The polyoxyalkylene glycol has a molecular weight of 1200 or less, preferably 10
Those having a relatively low molecular weight of 00 or less are preferably used.

In the polyester block copolymer used in the present invention, the ratio by weight of the hard segment to the soft segment is from 20 to 70 to 80 to 30, preferably 25.
~ 50 to 75-50. If the number of hard segments is more than this, the resulting polyester block copolymer becomes hard and causes problems such as curling.
When the number of soft segments is large, the crystallinity of the obtained polyester block copolymer decreases, and it is difficult to use the polyester block copolymer as a polyester elastomer.

The segment length of the hard segment and the soft segment constituting the polyester block copolymer is preferably about 500 to 7000, more preferably 800 to 5,000 in terms of molecular weight. Although it is difficult to directly measure the segment length, for example, the total ratio of the components constituting the hard segment and the soft segment, the melting point of the polyester composed of the components constituting the hard segment, and the weight of the obtained polyester block. From the melting point of the coalescence, it can be estimated using Flory's melting point drop equation.

The polyester block copolymer of the present invention preferably has a melting point T (° C.) satisfying the following formulas (I) and (II).

[0014]

T ₀ −5>T> T ₀ −60 (I) T> T ′ + 10 (II) [where T ₀ is the melting point (° C.) of the polymer composed of the components constituting the hard segment, and T ′ is the hard Shows the melting point (° C) of the random copolymer consisting of all the components constituting the segment and the soft segment]

The process for producing the polyester block copolymer used in the present invention comprises producing a polyester comprising the components constituting the hard segment and a polyester comprising the components constituting the soft segment, respectively.
A method of melt-mixing and copolymerizing so that the melting point is lower by 50 to 60 ° C, still more preferably by 2 to 40 ° C than the polyester constituting the hard segment is preferable.

Since the melting point of the copolymer varies depending on the mixing temperature and time, it is preferable that the copolymer be prepared by adding a catalyst deactivator to deactivate the catalyst when the desired melting point is reached. . As the catalyst deactivator used for such a purpose, phosphorus oxyacid is preferable.

The polyester block copolymer used in the present invention has an intrinsic viscosity of 0.6 or more, preferably 0.8 to 1.5, measured at 35 ° C. in orthochlorophenol. If the intrinsic viscosity is lower than this, the strength is lowered, which is not preferable.

On the other hand, the butylene terephthalate used in the present invention is a polyester containing terephthalic acid and tetramethylene glycol as main components.
It may contain other dicarboxylic acids or glycols of less than 0 mol%.

The polytetramethylene terephthalate has an intrinsic viscosity (measurement method is the same as that of the polyester block copolymer) of 0.6 or more, more preferably 0.7 to 0.7.
1.5 is preferably used.

As the organic sodium carboxylate as the component (C) used in this composition, an organic sodium carboxylate having 10 to 40 carbon atoms is used, and an aliphatic carboxylic acid is particularly preferable, and an aliphatic monocarboxylic acid is particularly preferable. Sodium carboxylate is preferred. Sodium montanate, sodium palmitate and sodium stearate are particularly preferred.

As the component (C), a sodium salt of an organic phosphoric ester can also be preferably used. As the sodium salt of an organic phosphate, a compound represented by the following structural formula is particularly preferred.

[0022]

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As for the amount of the component (C), the higher the amount, the higher the transparency. However, if the amount is too large, it is not preferable because it is colored yellow. On the other hand, if the amount is small, transparency is insufficient, which is not preferable.

In the composition of the present invention, the weight ratio of the components (A), (B) and (C) is (A) :( B):
(C) = 100: (0-200) :( 0.5-10), preferably (A) :( B) :( C) = 100:
(5-100): (0.5-10), and more preferably (A) :( B) :( C) = 100: (5-10)
0): (1 to 5).

The composition of the present invention can be produced by a usual melt-mixing method. For example, a screw type continuous extruder can be used.

The composition thus obtained is melt-molded. At this time, the temperature of the cooling medium is preferably as low as possible. For example, in the case of injection molding, molding should be performed at a mold temperature of 50 ° C. or less, preferably 0 to 40 ° C. Further, in forming a sheet using a cooling roller, the temperature of the cooling roller is 50 ° C or less, preferably 0 to 0 ° C.
When the temperature is set to 40 ° C. and a cooling medium such as water is used in extrusion molding, it is preferable to set the medium temperature as described above.

Further, since the crystal grain size increases as the cooling rate decreases, it is preferable that the thickness of the molded product be about 1 mm or less in a portion where the thickness of the molded product is desired to be transparent. However,
Even if the thickness is thicker, the transparency is increased as compared with the case where the component (C) is not added. Therefore, when the material is translucent, the thickness is not necessarily limited.

The polyester block copolymer composition used in the present invention contains other polymers, stabilizers, pigments, dyes, flame retardants, nucleating agents, lubricants and other additives in addition to the polyester block copolymer composition. You may. The amount of these additives and polymers is 0.01 to 10 parts by weight based on 100 parts by weight of the composition of the present invention.

[0029]

The present invention will be described in detail with reference to examples. In the examples, “parts” means “parts by weight”.

The haze was measured with a reflection / transmission meter (HR-10).
0; manufactured by Murakami Color Research Laboratory).

The heat treatment was carried out by keeping in air at 120 ° C. for one day.

Reference Example 1 Dimethyl terephthalate 194
And 160 parts of triethylene glycol, were subjected to a transesterification reaction with a dibutyltin diacetate catalyst, and then polycondensed under reduced pressure to obtain a starch-like polyester (A) having an intrinsic viscosity of 0.76. Polybutylene terephthalate (a) having an intrinsic viscosity of 0.98 obtained by separately polycondensing this polyester.
Was dried, 107 parts were added, and the mixture was further reacted at 250 ° C. for 75 minutes.
The reaction was stopped by adding one part. The polyester block copolymer was taken out and made into chips to be used as a raw material. The melting point of the chip was 176 ° C. and the intrinsic viscosity was 0.83.

Reference Example 2 Dimethyl Terephthalate 180
Part, 20 parts of dimethyl sebacate, 140 parts of tetraethylene glycol and 30 parts of diethylene 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 and the same polybutylene terephthalate chip (107 parts) as in Reference Example 1 were used to form a block in the same manner as in Reference Example 1 to obtain a polyester block copolymer.
Chips.

Example 1 80 parts of the polyester block copolymer of Reference Example 1, polytetramethylene terephthalate (intrinsic viscosity 1.02) and sodium palmitate 2
The section was melt extruded at 250 ° C. with an extruder. Extruded polyester block copolymer into chips
After drying, the mold temperature is 20 ° C and the cylinder temperature is 240
Injection molding was performed at ℃ to obtain a flat plate having a thickness of 1 mm. Although this plate was slightly cloudy, it was transparent enough to see the other side, and the haze measured by a haze meter was 45%.

[Comparative Example 1] In Example 1, when molding was performed without using sodium palmitate, a flat opaque plate was obtained, and the haze was 85%.

Examples 2 to 4, Comparative Example 2 In Example 1, when the polyester block copolymer of Reference Example 2 or 3 was used instead of the polyester block copolymer of Reference Example 1, Table 1 shows the results when the amount of tetramethylene terephthalate was changed.

[0037]

[Table 1]

[Examples 5 to 8] Table 2 shows the results obtained in Example 1 using various sodium salts in place of sodium palmitate.

[0039]

[Table 2]

From Examples 1 to 8, it can be seen that the composition of the present invention has high transparency and high heat resistance of transparency.
A short molding cooling time is sufficient, indicating that the elastomer is excellent in moldability.

[0041]

According to the present invention, a polyester elastomer composition having high moldability, high heat resistance and good moldability can be obtained.

Claims (1)

[Claims] 1. (A) 20 to 70% by weight of a hard segment containing terephthalic acid and tetramethylene glycol as main components of polybutylene terephthalate at 60 mol% or more per dicarboxylic acid component, aromatic dicarboxylic acid and HO (CH _{2 CH 2 O) i H (i} = 2~5) long chain diol is a polyester at least 60 mol% per the dicarboxylic acid component soft segment 80 to 30 wt%
At least one selected from 0 to 200 parts of (B) polybutylene terephthalate, and (C) a sodium salt of an organic carboxylic acid having 7 to 40 carbon atoms and a sodium salt of an organic phosphoric acid partial ester.
A polyester block copolymer composition comprising 0.5 to 10 parts by weight of a seed.