JPS5858380B2 - Polyester material - Google Patents

Description

[Detailed description of the invention] The present invention relates to polyester elastomer compositions.

More specifically, the present invention relates to a polyester elastomer composition that has good mold releasability, can shorten the molding cycle, and provides an injection molded product with a good appearance without surface sink marks.

Furthermore, the molded article obtained from the composition of the present invention has excellent transparency and high tensile strength at break, as well as good elastic recovery and relaxation rates.

In recent years, polyether ester block copolymers (hereinafter sometimes abbreviated as polyether esters), which have terephthalic acid as an acid component and tetramethylene glycol and high molecular weight polyoxydialkylene gelicol as diol components, have been developed for their good properties. It is attracting attention because of its moldability, heat resistance, low-temperature properties, etc.

However, if the polyether ester block copolymer contains a large amount of polyoxyalkylene glycol component (for example, if this content exceeds 60 parts by weight) or if a part of the terephthalic acid and/or tetramethylene glycol is Polyetherester block copolymers substituted with dicarboxylic acids and/or other low molecular weight glycols (hereinafter sometimes abbreviated as copolymerized polyetheresters) have poor mold release properties during molding, and the molding cycle is short. In addition, there are many undesirable problems such as the formation of sink marks on the surface of the molded product.

One way to solve these molding problems is to
It has been proposed to add a sodium salt (especially sodium stearate) of a linear aliphatic saturated monocarboxylic acid having 10 to 20 carbon atoms to the above polyether ester or copolymerized polyether ester (JP-A-50-11784).
(See Publication No. 5).

However, although this method can improve mold releasability, sink marks still appear on the molded products obtained, and
It is difficult to obtain good injection molded products.

In order to solve these problems, the inventors conducted intensive studies and arrived at the present invention.

That is, the present invention provides (4) a dicarboxylic acid component mainly consisting of terephthalic acid, a low molecular weight glycol component mainly consisting of tetramethylene glycol, and an average molecular weight ranging from 600 to 580 per weight of the polyether ester block copolymer. 100 parts by weight of a polyether ester block copolymer containing a polyoxyalkylene glycol component consisting of a polyoxyalkylene glycol of 6,000% and (8) sodium salt of monk wax acid o, oi~5
Parts by weight of a polyester elastomer composition.

The dicarboxylic acid component constituting the polyether ester block copolymer of component (4) above is mainly terephthalic acid, but a portion thereof (less than 50 molar proportion of the total acid components, preferably less than 40 molar proportion, (more preferably 30 molar or less) can be replaced with other dicarboxylic acids.

Examples of the other dicarboxylic acids include isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. Aromatic dicarboxylic acids: Alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid: succinic acid, adipic acid,
Aliphatic dicarboxylic acids such as sepacic acid, dodecanedioic acid, etc. can be mentioned.

One type of these can be used, but two or more types can also be used in combination.

In addition, the low molecular weight glycol component is mainly tetramethylene glycol, but a part of it (low molecular weight glycol component of 50 molar or less, preferably 40 molar or less, more preferably 30 molar or less) has a molecular weight of 300 or less. can be replaced with other low molecular weight glycols.

Examples of other low molecular weight glycols include ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, 1,1-cyclohexane dimetatool 1,4-cyclohexane di Metatool, tricyclodecane dimetatool, xylylene glycol, bis(P-hydroxy)diphenyl, bis(P-hydroxyphenyl)propane, 2,2bis(4-(2-hydroxyethoxy)phenyl)propane, bis (4-(2-hydroxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenylcocyclohexane, etc.).

One type of these can be used, but two or more types can also be used in combination.

Furthermore, the polyoxyalkylene glycol component has a molecular weight of 600 to 6000, preferably 600 to 3.
000, and polyoxyalkylene glycols having a carbon atom/oxygen atom ratio of approximately 2 to 45 are preferred, with polyoxyethylene glycol and polyoxytetramethylene glycol being particularly preferred.

The amount of the polyoxyalkylene glycol component is 5 to 8 based on the total weight of the polyether ester block copolymer.
0 weight ratio or 10 to 70 weight ratio weight.

The polyether ester block copolymer made of the above-mentioned components can be produced by a known method.

For example, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol, and a polyoxyalkylene glycol is transesterified in the presence of a catalyst, and the resulting reaction product is polycondensed; Examples include a method in which polyoxyalkylene glycol is subjected to an esterification reaction in the presence of a catalyst, and the resulting product is polycondensed.

As a common catalyst for transesterification or esterification reactions and polycondensation reactions, titanium catalysts give good results.

Particularly preferred are tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate; titanium oxalate metal salts such as potassium titanium oxalate; and the like.

Examples of other catalysts include tin compounds such as dibutyltin oxide and dibutyltin dilaurate, and lead compounds such as lead acetate.

The polyether ester block copolymer used in the present invention as component (4) preferably has a reduced viscosity of 1 to 4.

Further, the polyether ester block copolymer may contain a known stabilizer (for example, a heat-resistant stabilizer, a light-resistant stabilizer, etc.).

As the heat stabilizer, for example, 4,4/-bis(2,6-
phenolic compounds such as ditert-butylphenol),
Examples include amine compounds such as N,N'-bis(β-naphthyl)-p-phenylenediamine, and sulfur compounds such as dilaurylthiodipropionate.

Examples of light stabilizers include substituted benzophenone,
Examples include benzotriazole compounds.

The composition of the present invention consists of a polyether ester block copolymer as the component (4) and a sodium salt of monk wax acid as the component (2).

This Monkwax acid is an acid mixture consisting primarily of aliphatic monocarboxylic acids with a chain length of 26 to 32 carbon atoms.

The sodium salt of monk's wax acid is usually produced by a neutralization reaction between monk's wax acid and a sodium compound such as sodium hydroxide, but in this case, the sodium equivalent is 0 relative to the acid equivalent of monk's wax acid. .5 or more, preferably 0.7 or more, more preferably 0. g equivalent or more1. It is desirable that the amount is less than or equal to O equivalent.

The amount of the thorium salt of monk's wax acid is 0.0 parts by weight per 100 parts of the polyether ester block copolymer.
0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, more preferably o, i to 1 parts by weight.

The method of mixing the sodium salt of Monchun wax acid is arbitrary, for example, adding it to a polymerization pot during or after the production of the polyether ester block copolymer and melt-mixing it, or adding it together with the polyether ester block copolymer chips. Examples include a method of melt-mixing using an extruder.

Also, the same effect can be obtained by mixing it with solid polyetherester block copolymer chips before injection molding and using it directly for injection molding.

In the present invention, a known crystallization accelerator (for example, talc, alkaline earth carbonate, titanium oxide, aluminum oxide, etc.) may be used together with the sodium salt of monk's wax acid.

The injection molded product obtained from the composition of the present invention has good mold releasability, has a good appearance with no sink marks on the surface, and has good heat resistance, weather resistance, transparency, tensile strength at break, and elastic recovery rate. and relaxation rate have been greatly improved.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that "parts" in the examples mean parts by weight.

In addition, the reduced viscosity shown in the text and examples is that of polymer 1200.
Dissolve ■ in 10011 Ll of orthochlorophenol,
This is a value measured at 35°C.

The softening point of the polymer is a value measured with a needle-type softening point measuring device.

Tensile breaking strength and elongation are according to JISK-6301.
Measurement was performed using a No. 3 dumbbell.

Furthermore, the elastic recovery rate was 50% elongated, then relaxed for 5 minutes,
It is expressed as the length recovery rate immediately after the load is removed.

The relaxation rate was determined from the stress at the time of 50 modulus elongation and the stress after relaxation for 5 minutes.

Example 1 and Comparative Examples 1 and 2 In a reactor equipped with a rectification column, 1-56.1 parts of dimethyl terephthalate, 241 parts of dimethyl isophthalate, 55.8 parts of tetramethylene gellicol, and polytetramethylene with an average molecular weight of 1.000 were added. 60 parts of glycol 1O and 0.042 parts of tetrabutyl titanate were charged, and transesterification was carried out at an internal temperature of 170 to 220°C until the theoretical amount of 90 methanol was distilled out.

The obtained reaction product was transferred to a polymerization reactor, followed by 10 minutes of normal pressure reaction at a temperature of 240°C, 30 minutes of medium vacuum reaction of 15 to 20 m7 ILHJ, and further 0.3 to 0.11 n) (high vacuum reaction of 9 was carried out for 2 It took 10 minutes.

After the high vacuum reaction, the reaction system was returned to normal pressure, 1.0 part of Irganox 1035 (Findert phenol compound) manufactured by Ciba Geigy was added as a stabilizer, and then the degree of vacuum was gradually increased. After stirring and mixing under high vacuum for 10 minutes, the reaction product was taken out, cooled, and chipped.

The resulting polyetherester block copolymer had a reduced viscosity of 1.70 and a softening point of 170.4°C.

After drying the obtained polyether ester block copolymer, polyether ester block copolymer 100
Mix 1 part to 1 part of Monchun wax acid sodium salt or sodium stearate to a cylinder temperature of 2.
After passing through transesterification at 00° C. and melt-mixing, the mixture was rechiped.

The sodium salt of monchun wax acid used here was Hoechst Wax S■ (acid value 147) manufactured by Hoechst.
and an equivalent amount of sodium hydroxide.

The chips with the additives or the chips without additives were injection molded at a cylinder temperature of 205°C and a mold temperature of 55°C, and the mold releasability, injection cycle, presence or absence of surface sink marks, and molded products were evaluated. The tensile strength and elongation at break, elastic recovery rate, and relaxation rate were investigated.

The results were as shown in the table below.

As is clear from the above table, the molded products obtained from the polyether ester block copolymer mixed with the sodium salt of monk wax acid have a good appearance without any sink marks, and have good tensile strength and elasticity. It can be seen that the recovery rate and relaxation rate are also good.

On the other hand, when sodium stearate was mixed, sink marks appeared and the elastic recovery rate decreased.

Furthermore, this material has poor heat resistance and weather resistance compared to the material of the present invention.

Example 2 and Comparative Examples 3 and 4 48.0 parts of dimethyl terephthalate, 16.0 parts of dimethyl isophthalate, 59.5 parts of tetramethylene glycol
30.0 parts of polyoxytetramethylene glycol with an average molecular weight of 1000 and 0.0 parts of tetrabutyl titanate)
The reaction was carried out using the same equipment and operation as in Example 1, except that 56 parts were used, and the reduced viscosity was 1.76 and the softening point was 171.1'.
Chips of polyetherester block copolymer C were obtained.

This polyether ester block copolymer chip lO
1 part of sodium waxate in part O (Example 2)
Or, by mixing 1 part of sodium stearate (Comparative Example 3), the cylinder temperature was 210°C and the mold temperature was 55°C.
Injection molding was performed.

A polyether ester block copolymer without the above additives was also molded under the above conditions (Comparative Example 4).

The molding cycle was 25 seconds when sodium waxate or sodium stearate was used and 30 seconds when no additives were added.

Although mold releasability was good in all cases, molded products other than those using sodium chloride wax had sink marks and poor appearance.

Claims (1)

[Scope of Claims] 1(A) A dicarboxylic acid component mainly consisting of terephthalic acid, a low molecular weight glycol component mainly consisting of tetramethylene glycol, and a weight ratio of 5 to 80 per weight of the polyether ester block copolymer. 100 parts by weight of a polyether ester block copolymer containing a polyoxyalkylene glycol component consisting of polyoxyalkylene glycol of 600 to 6,000 and (6) 0.01 to 5 parts of sodium salt of monk wax acid.
A polyester elastomer composition consisting of parts by weight.