JPH06306262A - Polyester elastomer composition - Google Patents

Abstract

PURPOSE:To obtain the composition having excellent moldability, heat-resistance and flexibility by mixing respective specific aromatic polyester, aliphatic polycarbonate diol, pyromellitic anhydride, etc., at specific ratios. CONSTITUTION:The objective composition is produced by mixing (A) 100 pts.wt. of an aromatic polyester copolymerized with >=40wt.% of polytetramethylene glycol with (B) 10-100 pts.wt. of an aliphatic polycarbonate diol having an average molecular weight of 500-3,000, (C) 0.5-20 pts.wt. of pyromellitic anhydride and/or trimellitic anhydride and preferably (D) 0.1-2 pts.wt. of 2,2'-bis(2-oxazoline).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester elastomer composition having flexibility. For more details,
The present invention relates to a flexible composition which suppresses deterioration of moldability and heat resistance of a polyester elastomer.

[0002]

2. Description of the Related Art Aromatic polyesters copolymerized with polytetramethylene glycol are well known as polyester elastomers. This polyester elastomer is widely used by taking advantage of heat resistance, moldability, chemical resistance and the like. However, since this polyester elastomer generally has an intermediate hardness between rubber and plastic, it is often too hard to substitute for rubber.

In such a case, generally, a method of increasing the amount of polytetramethylene glycol as a soft component or copolymerizing an aromatic polyester as a hard component is used. However, when such a method is used, the melting point is lowered and the crystallinity is also lowered, so that the characteristic of the polyester elastomer, which is one of the good moldability, is lost, which is not preferable.

There is also a method of softening by adding a plasticizer, but there is a bleeding out of the plasticizer. For example, when injection molding is repeated, mold stains occur and it is necessary to clean the mold frequently. There are inconveniences such as

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible polyester elastomer composition having less deterioration of moldability and less exudation of a plasticizer.

[0006]

As a result of repeated studies to solve the above problems, the inventors of the present invention added a reaction product of a polycarbonate diol and an acid anhydride to a polyester elastomer to make it flexible, and It was found that moldability and bleeding were also reduced.

That is, according to the present invention, << claim 1 >> 100 parts by weight of an aromatic polyester copolymerized with at least 40% by weight of polytetramethylene glycol is added to an average molecular weight of 50.
0-3000 aliphatic polycarbonate diols 10-
A polyester elastomer composition obtained by mixing 100 parts by weight with 0.5 to 20 parts by weight of at least one of pyromellitic anhydride and trimellitic anhydride, and at least 40 parts of << claim 2 >> polytetramethylene glycol. % To 100 parts by weight of an aromatic polyester copolymerized with 10 to 100 parts by weight of an aliphatic polycarbonate diol having an average molecular weight of 300 to 3000, and at least one of pyromellitic anhydride and trimellitic anhydride 0.5 to 20 A polyester elastomer composition comprising 1 part by weight and 0.1 to 2 parts by weight of 2,2'-bis (2-oxazoline).

The present invention will be described.

The aromatic polyester copolymerized with at least 40% by weight of polytetramethylene glycol is a copolymer having a soft segment of polytetramethylene glycol having an average molecular weight of 600 to 3000, or with this copolymer. It is a block copolymer of a polyester of an aromatic dicarboxylic acid and an aliphatic and / or aliphatic diol. This copolymer preferably has a melting point of 170 ° C. or higher.

The aromatic dicarboxylic acid is particularly preferably terephthalic acid or 2,6-naphthalenedicarboxylic acid, and the diol is preferably tetramethylene glycol. These acid component and diol component may be copolymerized in an amount of 20 mol% or less. The dicarboxylic acid or diol to be copolymerized is not particularly limited.

As the polytetramethylene glycol, a copolymerized product may be used. The copolymerization component is
Ethylene glycol residue, propylene glycol residue,
Examples thereof include 2,2-bis (4-hydroxyphenyl) propane residue and the like, and these are usually copolymerized in an amount of 20 mol% or less. Of course, homopolymers are common. The copolymerization amount of this polytetramethylene glycol in the block copolymer is 40% by weight or more, preferably 5% by weight or more. This weight percent is calculated as follows.

The weight in the form of polytetramethylene glycol (the weight of the charged polymerization reaction) was calculated on the assumption that the total amount of polytetramethylene glycol remained, and the percentage (%) based on the weight of the theoretically obtained block copolymer. ).

This block copolymer has an intrinsic viscosity (35
℃, measured in orthochlorophenol) 0.8 or more,
It is preferably 1.0 or more.

On the other hand, the polycarbonate diol means a compound in which an aliphatic diol is carbonate-bonded and a terminal of which is a hydroxyl group. In the present invention, (polyhexamethylene) diol is particularly preferably used. This polycarbonate diol has an average molecular weight of 1,000 to 300.
Those in the range of 0 are used.

Pyromellitic dianhydride and / or trimellitic dianhydride, which are the third addition component, are preferably pyromellitic dianhydride, but those of the level of ordinary reagents can be used. It is desirable that the 2,2′-bis (2-oxazoline) used as necessary is purified by sublimation before use.

The amount of pyromellitic dianhydride and / or trimellitic dianhydride used is 0.5 to 20 parts, but the amount (mol number) of the polycarbonate diol used is 0.9 to
About 1.1 mole times is preferable. 2,2′-Bis (2-oxazoline) may not be used, but when it is used in an amount of 0.1 to 2 parts by weight, the viscosity becomes high and burrs at the time of molding are reduced. It is preferable to appropriately change the amount used depending on the application. 2,2'-bis (2-oxazoline) also has an effect of preventing bleeding to the surface.

In the present invention, the above polyester,
Polycarbonate diol, pyromellitic dianhydride and /
Alternatively, trimellitic anhydride may be mixed. Such mixing is usually performed by melt mixing. For example, a method is generally used in which the above components are simultaneously or separately supplied to an extruder and melt-extruded. At this time, 2,2′-bis (2-oxazoline) can be added, if necessary.

As another method of the present invention, a method in which the polycarbonate diol and the acid anhydride are preliminarily reacted and then supplied can be employed. This is the preferred method of the present invention. As the method of reacting in advance, the polycarbonate diol and the acid anhydride may be heated and mixed, and the reaction may be carried out until they become uniform. This reaction product does not necessarily have to be wholly reacted, so the reaction conditions may be set appropriately.
The reaction product may be mixed with the polyester as in the unreacted case. Also in this case, it is preferable to add 2,2′-bis (2-oxazoline) in the same manner.

The composition thus obtained is shaped and used by injection molding, extrusion molding, blow molding or the like.

The composition of the present invention may contain stabilizers, reinforcing materials, pigments, dyes, release agents, lubricants and other additives.

[0021]

By carrying out the present invention, an elastomer which is significantly softer than the original polyester elastomer can be obtained, and the moldability of this composition is not so different from the original polyester elastomer. Also, the melting point is not significantly lowered.

[0022]

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

[0023]

Example 1 and Comparative Example 1 63 parts of polytetramethylene glycol (molecular weight 2000), dimethyl terephthalate 3
3 parts and 35 parts of tetramethylene glycol were polycondensed according to a conventional method to obtain an intrinsic viscosity (in orthochlorophenol, 3 parts).
A polyester elastomer of 1.48 (measured at 5 ° C.) was obtained.

To 100 parts of this polyester elastomer, 50 parts of poly (hexamethylene carbonate) diol having a molecular weight of 2000, 5.4 parts of pyromellitic dianhydride and 0.7 part of 2,2'-bis (2-oxazoline) were mixed,
Extruded at 240 ° C. in an extruder. Thickness of the obtained chip is 2
A flat plate of mm was injection-molded and a JIS No. 6301 No. 1 dumbbell was punched out from this to perform a tensile test. The mold temperature of this molding was 40 ° C., and the cooling time at this time was 30 seconds. As a measure of hardness, the stress measured at 50% elongation was 3.8 MPa. The melting point of this product was 182 ° C.

For comparison, a similar test was conducted using only the polyester elastomer, and as a result, the stress at 50% elongation was 6.1 MPa. It can be clearly seen that the composition of the invention is softened. Since the melting point of this elastomer is 190 ° C., it does not differ much from the melting point of the composition of the present invention.

In order to increase the flexibility of the polyester elastomer, the composition is the same as that in which the copolymerization amount of polytetramethylene glycol is increased, and the polytetramethylene glycol is charged in the above polycondensation in the same amount as 80 parts. Then, a polyester elastomer having an intrinsic viscosity of 1.50 was obtained, and the tensile test and the measurement of the melting point were performed.
The stress at 50% elongation was 4.2 MPa, but the melting point was 164 ° C., clearly lower than the composition of the invention. This polyester elastomer was slow to solidify even in injection molding and could not be molded because it adhered to the mold unless the cooling time was about 120 seconds.

[0027]

Example 2 In Example 1, dimethyl 2,6-naphthalenedicarboxylate was used instead of dimethyl terephthalate, and the polytetramethylene glycol had a molecular weight of 100.
It was set to 0 and the amount was 40 parts and polycondensation was carried out. The obtained polyester elastomer has a melting point of 198 ° C. and an intrinsic viscosity of 1.
It was 26.

To this elastomer was added 20 parts of the same polycarbonate diol as in Example 1, 2 parts of pyromellitic dianhydride, 2,2'-bis (2-oxazoline).
4 parts was added and the mixture was extruded at 250 ° C.

As a result of molding the obtained chips, it was possible to sufficiently mold them with a cooling time of 30 seconds.
The stress at% elongation was 5.0 MPa (6.7 MPa when no polycarbonate diol was added).

[0030]

Examples 3 to 5 Extrusion molding was performed in the same manner as in Example 1 except that the additives were changed as shown in Table 1 in Example 1. However, polyhexamethylene carbonate diol (average molecular weight 1000) (PCDL) and pyromellitic dianhydride (PMDA) are mixed at 100 ° C. under a nitrogen atmosphere.
Examples 3 and 4 were used by reacting with stirring for a time.
Then, 0.5 part of 2,2'-bis (2-oxazoline) was added, and 2,2'-bis (2-oxazoline) was not used in Example 5. In Example 5, the viscosity was slightly low, but no particular problem was observed. The obtained results are shown in Table 1.

[0031]

[Table 1]

[0032]

Example 6 A molded article was obtained in the same manner as in Example 4, except that 1.9 parts of trimellitic anhydride was added instead of pyromellitic dianhydride. A cooling time of 30 seconds was sufficient for molding this material, the stress at 50% elongation was 5.5 MPa, and the melting point was 187 ° C.

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Claims (2)

[Claims] 1. An aromatic polyester 100 copolymerized with at least 40% by weight of polytetramethylene glycol.
Polyester elastomer obtained by mixing 10 to 100 parts by weight of aliphatic polycarbonate diol having an average molecular weight of 500 to 3000 and 0.5 to 20 parts by weight of at least one of pyromellitic anhydride and trimellitic anhydride. Composition. 2. An aromatic polyester 100 copolymerized with at least 40% by weight of polytetramethylene glycol.
10 to 100 parts by weight of an aliphatic polycarbonate diol having an average molecular weight of 300 to 3000, 0.5 to 20 parts by weight of at least one of pyromellitic anhydride and trimellitic anhydride, and 2,2′-bis A polyester elastomer composition containing 0.1 to 2 parts by weight of (2-oxazoline).