JPH10237178A - Polyester elastomer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester elastomer excellent in heat resistance, oil resistance, wear resistance and impact resistance and having improved hydrolysis resistance by specifying each of hard and soft segments. SOLUTION: This polyester elastomer is composed of the following two segments: (A) a hard segment consisting of a polyester of a melting point of 220-320 deg.C consisting mainly of a polyalkylene naphthalate, preferably polyethylene naphthalate and (B) a soft segment consisting of an aliphatic polyester having an average block chain length of 1,000-5,000, preferably polycaprolactone. The objective elastomer is obtained preferably by coupling the component A with the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyester elastomer excellent in hydrolysis resistance (heat aging resistance).
More specifically, it is excellent in heat resistance, oil resistance, abrasion resistance, impact resistance and hydrolysis resistance, hoses, tubes, belts,
The present invention relates to a polyester elastomer preferably used for parts such as gears, connectors, tanks, battery parts, sockets, cord coatings, bumpers, etc. for automobiles, large-sized machines, industrial machines, home electric appliances and the like.

[0002]

2. Description of the Related Art Polyester elastomers have been preferably used for automobile parts and the like due to their excellent properties such as heat resistance, oil resistance and impact resistance. However, polyester elastomers are inferior in hydrolysis resistance, easily undergo thermal deterioration at the time of processing, and a sharp decrease in strength and impact resistance,
It has serious drawbacks such as instability of the melt viscosity during molding and a problem in durability as an automobile part. For this reason, various studies have hitherto been made to improve the hydrolysis resistance of polyester elastomers. Japanese Patent Publication No. 3-77826 discloses that a monofunctional epoxy compound and a bifunctional epoxy compound are contained in an amount of 0.3 to 10% by weight in order to improve the hydrolysis resistance of a polyester elastomer.
Addition is described. 4-19
No. 267 describes that an epoxy compound having one or more functional groups, a weather resistance stabilizer and a tertiary phosphine are added. Although a certain level of improvement effect can be obtained by these methods, further drastic improvement is demanded.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester elastomer which has improved hydrolysis resistance of a polyester elastomer and is excellent in heat resistance, oil resistance, abrasion resistance and impact resistance. .

[0004]

Means for Solving the Problems The present inventors have found that the hard segment (A) is a polyester mainly composed of polyalkylene naphthalate, and the soft segment (B) is an aliphatic having an average block chain length of 1,000 to 5,000. The inventors have found that a high-melting polyester elastomer having a unique structure, which is a polyester, has excellent hydrolysis resistance and a method for producing the same, and have completed the present invention.

That is, according to the present invention, the hard segment (A) has a melting point of 2 mainly composed of polyalkylene naphthalate.
A polyester having a temperature of 20 to 320 ° C., wherein the soft segment (B) has an average block chain length of 1000 to 500;
A polyester elastomer characterized by being an aliphatic polyester of 0. Further, the present invention provides a polyester elastomer, wherein a hard segment (A) is mainly composed of polyalkylene naphthalate and has a melting point of 220 to 320 ° C. and an aliphatic polyester as the hard segment (A). A manufacturing method is provided.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The hard segment (A) of the polyester elastomer of the present invention is an aromatic polyester mainly composed of polyalkylene naphthalate, and has an aromatic polyester having a relatively high melting point in the range of 220 to 320 ° C, preferably 230 to 300 ° C. say. If the melting point is 220 ° C. or lower, there are some uses that cannot be used due to heat resistance. The melting point is 320 ° C
Exceeding the range is not preferable because decomposition of the soft segment occurs. The aromatic polyester is a polyester obtained by a condensation reaction of naphthalene acid or a lower ester thereof with glycol. Examples of the glycol include ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, and cyclohexanedimethanol. The ratio of the polyalkylene naphthalate in the hard segment (A) is preferably 60
% By weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more. If the proportion of the polyalkylene naphthalate is less than 60%, it is not preferable because the hydrolysis resistance and heat resistance of the obtained polyester elastomer decrease. The component other than the polyalkylene naphthalate in the aromatic polyester is a polyester obtained from an aromatic dicarboxylic acid represented by terephthalic acid or isophthalic acid or a lower ester thereof, and is usually used together with naphthalene acid or a lower ester thereof. Condensed.

The component of the soft segment (B) constituting the polyester elastomer of the present invention is an aliphatic polyester having an average block chain length of 1,000 to 5,000.
Aliphatic polyesters are mainly ester bonds and
Or a polymer comprising an ether bond, having a hydroxyl group and a carboxyl group at the molecular terminal. ^The average block chain length calculated from ¹³ C-NMR is 1000 to 5000, preferably 1500 to 4000, more preferably 2000
Use up to 3000 aliphatic polyesters. If the average block chain length is smaller than 1000, the rigidity and heat resistance decrease, which is not preferable. On the other hand, if it exceeds 5,000, the toughness decreases, which is not preferable. Representative examples of the aliphatic polyester include polylactones, condensates of an aliphatic dibasic acid and glycol, and condensates of various hydroxyalkylcarboxylic acids. Specific examples thereof include polycaprolactone, caprolactone-based copolymers (these are referred to as polycaprolactones), condensates of adipic acid and ethylene glycol, 1,4-butanediol or neopentyl glycol, sebacic acid and the like. Examples include condensates of succinic acid and the above-mentioned glycols. Among these, polycaprolactones, particularly polycaprolactone, are preferred as the soft segment (B).

In producing a polyester elastomer,
The mixing ratio of the hard segment (A) and the soft segment (B) is preferably such that the hard segment (A) is 50.
To 95% by weight (the total of the hard segment (A) and the soft segment (B) is 100% by weight), more preferably 60 to 90% by weight, and particularly preferably 60 to 80% by weight. When the content of the hard segment (A) is less than 50% by weight, the rigidity and heat resistance of the obtained polyester elastomer are undesirably reduced. On the other hand, if it exceeds 95% by weight, it is not preferable because the toughness of the polyester elastomer is poor.

The reaction temperature of the coupling reaction is desirably in the range from the melting point of the polyester mainly composed of polyalkylene naphthalate, which is the hard segment (A) of the raw material, to 300 ° C. If the temperature exceeds 300 ° C. (transesterification reaction or depolymerization reaction occurs), decomposition and coloring occur, which is not preferable. The reaction time is preferably 10
Minutes to 2 hours, more preferably 20 minutes to 1 hour. If the reaction time is less than 10 minutes, the reaction is insufficient and rigidity and elasticity are low.
On the other hand, if it exceeds 2 hours, the transesterification reaction or the depolymerization reaction proceeds, and the strength is reduced and coloring is not preferred.
As the production apparatus, for example, the hard segment (A) resin and the soft segment (B) resin are supplied to one extruder and melt-kneaded, or melt-kneaded by a heating roll or a Banbury mixer, and then pelletized or pulverized. Can be obtained.

In the coupling reaction, an isocyanate group-containing compound having one or more isocyanate groups in the same molecule may be added. Examples of isocyanate group-containing compounds include, for example, diphenylmethane diisocyanate (MDI), tolylene diisocyanate, polymeric MDI, dianisidine diisocyanate, diphenyl ether diisocyanate, orthotrizine diisocyanate, naphthalenediisocyanate, triphenylmethane triisocyanate, triisocyanate phenyl thiophosphate, hexa Methylene diisocyanate,
Isophorone diisocyanate, lysine diisocyanate methyl ester, meta-xylylene diisocyanate,
Examples include 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, isopropylidenebis-4-cyclohexyl isocyanate, dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, and dimer of tolylene diisocyanate. Two or more isocyanates may be used in combination. Of these, hexamethylene diisocyanate is preferably used.

The polyester elastomer obtained according to the present invention may contain, if necessary, various additives such as a heat stabilizer, a crosslinking agent, an ultraviolet absorber, silica, talc,
An inorganic filler such as carbon, a plasticizer, and a softener such as oil can be compounded and used.

Further, the polyester elastomer of the present invention is excellent in heat resistance, oil resistance, abrasion resistance, impact resistance and hydrolysis resistance, and can be used alone or in combination with other resins to form a sheet, film, It can be used as various molded products such as injection molded products of various shapes and hollow molded products.
Further, the polyester elastomer of the present invention alone or a composition containing the same may be molded into a multilayer or a composite with another resin to form a hose, tube, belt, gear, connector, tank, battery component, socket, cord cover, bumper, etc. Of automobiles, large machines, industrial machines, home appliances, toys and the like.

[0013]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. (Measurement and evaluation method) Melt viscosity: Melt Flow Tester using Shimadzu (Ltd.), 240 ℃, 10kg / cm 2 2. 2. A / B weight ratio: weight ratio of hard segment (A) to soft segment (B), calculated from ¹ H-NMR A block chain length, B block chain length: Average block chain length of hard segment (A) and average block chain length of soft segment (B), calculated from ¹³ C-NMR, Reference “Polymer Collection” Vol.49 , No.7, pp561-568 (Jul.19
92) The average block chain length is the average chain length referred to in this document, and is determined by the product of the average number of chains and the molecular weight of each repeating unit. 4. Tensile strength 50% modulus (kg / cm ² ): JIS
K7113 5. Breaking strength (kg / cm ² ): JIS K7113 6. Elongation at break (%): JIS K7113 7. Melting point (° C.): JIS K7121 Crystal temperature (° C): JIS K7121 9. Hardness (Shore D): JIS K7215

(Example 1) Polyethylene naphthalate (manufactured by Teijin; melting point: 270 ° C) and polycaprolactone manufactured by Daicel Chemical Industries, Ltd. are respectively 6 kg / hr and 4 kg / hr, and the average residence time is 10 minutes. The mixture was fed to the inlet of a twin-screw extruder. 280 in the extruder
The mixture was melt-mixed at ℃, the discharged strand was cooled with dry cooling air, and cut with a pelletizer. The discharge strand was slightly clouded in a molten state. Then, in order to further advance the reaction between polyethylene naphthalate and polycaprolactone, the obtained pellets were again melt-mixed at 280 ° C. for about 10 minutes using the same extruder. The discharge strand became transparent in the molten state. This was cooled with dry cooling air and cut with a pelletizer to obtain a pelletized polyester elastomer (1).

(Example 2) [0015] The polyester elastomer (1) pellets obtained in Example 1 were placed in a charging port of a twin-screw extruder having an average residence time of 5 minutes by using a quantitative feeder.
It was fed at 5 kg / hr. At the same time, 0.3 kg /
Using a metering pump at hr, the mixture was fed to the feed port of the same extruder and melt-mixed at 280 ° C. Thus, the chain extension of the polyester elastomer (1) was performed, and a polyester elastomer (2) was obtained. The physical properties and mechanical properties of the polyester elastomers (1) and (2) obtained in Examples 1 and 2 were evaluated and are shown in Table 1.

[0016]

[Table 1]

[0017]

As described above, the polyester elastomer of the present invention has improved hydrolysis resistance and has heat resistance, oil resistance, abrasion resistance and impact resistance. It can be used alone or in combination with other resins, or in combination with other resins, as various molded articles such as sheets, films, injection molded articles of various shapes, and hollow molded articles.

Claims (3)

[Claims] 1. The hard segment (A) is a polyester mainly composed of polyalkylene naphthalate and having a melting point of 220 to 320 ° C., and the soft segment (B) is an aliphatic polyester having an average block chain length of 1,000 to 5,000. A polyester elastomer, characterized in that: 2. The polyester elastomer according to claim 1, wherein the hard segment (A) is polyethylene naphthalate and the soft segment (B) is polycaprolactone. 3. A polyester elastomer comprising a polyester having a hard segment (A) mainly composed of polyalkylene naphthalate and having a melting point of from 220 to 320 ° C. and an aliphatic polyester serving as a soft segment (B). Manufacturing method.