JPH0826130B2 - Aliphatic polyester - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aliphatic polyester having improved heat resistance, and more particularly to an aliphatic polyester preferably used as a molding material.

(Prior Art) Generally, in order for a material to exhibit rubber elasticity, it is necessary that an amorphous polymer whose molecular chain rotation is easy is partially crosslinked. For example, in rubber having elasticity, sulfur molecules bridge between molecular chains by a chemical bond to form a network structure. In addition to rubber, materials in which various polymer compounds and a crosslinking agent are combined have been proposed. Cross-linking materials cannot be molded by injection molding or extrusion because they require a cross-linking step to mold these materials and they do not exhibit thermoplasticity after being chemically cross-linked.

In recent years, thermoplastic elastomers that exhibit rubber elasticity at room temperature and are plasticized at high temperatures have been developed, and various types of thermoplastic elastomers have been manufactured and sold. This thermoplastic elastomer does not require a long-time cross-linking step unlike the conventional rubber, and can be molded by injection molding or extrusion molding.

The characteristic of the molecular structure of the thermoplastic elastomer is the cross-linking that does not rely on a strong chemical bond, that is, a system that applies some kind of inter-polymer constraint that is effective only at around room temperature, and is a polymer assembly consisting of soft and hard segments. The body is the typical structure of thermoplastic elastomers. The chemical structure of the soft segment is different from that of the hard segment. In the hybrid composition of the soft segment and the hard segment, the homogeneous portions are aggregated and the heterogeneous portions are phase-separated from each other to form a microscopic imbalanced structure. At that time, the agglomerated portion of the hard segment exhibits a binding effect between the molecules.

Examples of the thermoplastic elastomer include styrene type, olefin type, urethane type, ester type and amide type. In the styrene type, polystyrene forms a frozen phase as a hard segment and restrains between molecular chains, resulting in rubber elasticity. In the olefin system, the crystalline phase of polypropylene acts as a hard segment. Further, in the urethane type, the polyurethane segment causes physical cross-linking between molecular chains by hydrogen bond. Further, a polybutylene terephthalate chain works as a hard segment in the ester system, and a nylon chain such as 6-nylon or 6-6 nylon works as a hard segment in the amide system.

(Problems to be Solved by the Invention) As described above, since the thermoplastic elastomer exhibits rubber elasticity at room temperature and can be molded, it is widely used for automobile parts and various industrial products. However, conventional thermoplastic elastomers have lower heat resistance due to the restriction of the softening melting point of the part because the cross-linking is performed by physical restraint as compared with cross-linking type rubber, and the creep property is also inferior. Was becoming. For example, the melting point of Perprene S-9001 manufactured by Toyobo Co., Ltd., which is known as the ester type having the highest heat resistance among thermoplastic elastomers,
223 ℃, heat distortion temperature (low load) 146 ℃, even in the urethane system, its softening point is 140 ℃ at most.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an aliphatic polyester which has performance as a thermoplastic elastomer, is excellent in heat resistance and mechanical properties, and is also excellent in molding processability.

(Means for Solving the Problems) In the present invention, a segment based on a compound represented by the following formula [I] having a remarkably high crystallinity as a hard segment and a melting point of 300 ° C. or more is formed between the molecular chains of the aliphatic polyester. Alternatively, the present invention has been completed based on the finding that a thermoplastic elastomer having a high melting point and excellent heat resistance can be obtained by introducing it at the terminal.

That is, the aliphatic polyester of the present invention has the following formula [I]
And a dihydroxy compound represented by the following general formula [II]
And an aliphatic dicarboxylic acid represented by the following general formula [II
I) represented by alkylene glycol as a main constituent component, the dihydroxy compound is blended in a proportion of 0.1 to 30 mol% of the diol component formed by combining the dihydroxy compound and the alkylene glycol, o- The limiting viscosity measured by an Ubbelohde viscometer using a dilute solution of chlorophenol at 30 ° C. is 0.4 or more and 2.0 or less, which achieves the above object.

(Wherein, R represents -H, or _{-CH 2 CH 2 OH) HOOC- (} CH 2) ( wherein, n an integer of 0) n-COOH [II] HO- (CH ₂₎ n -OH [III] (In the formula, n is an integer of 2 to 10) The dihydroxy compound represented by the above formula [I] is a low molecular weight compound exhibiting liquid crystallinity, and specifically represented by the following formula [IV]. 4,4 "-dihydroxy-p-terphenyl and 4,4" -di (2-hydroxyethoxy) -p-terphenyl represented by the following formula [V].

These liquid crystalline molecules generally have high crystallinity and are 4,4 "
-Dihydroxy-p-terphenyl and 4,4 "-di (2
-Hydroxyethoxy) -p-terphenyl has a high transition point, so that when these dihydroxy compounds are incorporated into the polymer chain, it results in very strong physical crosslinks with high heat resistance and high heat resistance. It is assumed that a thermoplastic elastomer is produced. These dihydroxy compounds may be used alone or in combination.

The above alkylene glycol has the general formula HO- (CH ₂ ) n-OH
The one represented by (n is an integer of 2 to 10) is used, and the alkylene glycol having more than 10 carbon atoms is not used because the physical properties are deteriorated. As the alkylene glycol, for example, ethylene glycol, propylene glycol and butylene glycol are preferably used. Further, another diol component may be used as long as it does not deteriorate the physical properties by substituting a part of the alkylene glycol. The diol component includes propylene-1,2-diol, butane-1,2-diol, butane-1,3-diol, and substituted aliphatic diols such as neopentyl glycol; hydroquinone, resorcin, methylhydroquinone, chlorohydroquinone, Bromohydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4 '
-Aromatic diols such as dihydroxybiphenyl and 2,6-naphthalene diol; and alicyclic diols such as 1,4-cyclohexanediol.

In the present invention, the dihydroxy compound and the alkylene glycol are used in combination. The mixing ratio of the dihydroxy compound in the diol component formed by combining the dihydroxy compound and the alkylene glycol is preferably 0.1 to 30 mol% in terms of molar ratio. When the molar ratio of the dihydroxy compound in the diol component is less than 0.1%, physical cross-linking by the hard segment becomes insufficient, and sufficient physical properties, particularly heat resistance, are difficult to develop.
Further, when the molar ratio of the dihydroxy compound in the diol component exceeds 30%, the elastic modulus of the aliphatic polyester tends to be high and tends to be unsuitable as an elastomer. However, it has high heat resistance and can be suitably used as a thermoplastic resin having excellent mechanical properties.

The above aliphatic dicarboxylic acid has the general formula HOOC- (CH ₂ )
What is represented by n-COOH (n is an integer of 0 to 10) is used, and the physical properties of the dicarboxylic acid having more than 10 carbon atoms are deteriorated. Examples of the aliphatic dicarboxylic acid include oxalic acid,
Malonic acid, succinic acid, glutaric acid, adipic acid and the like are preferably used. Further, other dicarboxylic acids may be used as long as they do not deteriorate the physical properties by substituting a part of these aliphatic dicarboxylic acids. Examples of the dicarboxylic acid include alkyl groups such as methyl group, ethyl group, n-propyl group and iso-propyl group; alkoxy groups such as methoxy group and ethoxy group; allyloxy groups such as phenoxy group; chloro group, bromine group and the like. Aliphatic dicarboxylic acids substituted with halogen groups, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, aromatic dicarboxylic acids such as 4,4 ″ -biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. And alicyclic dicarboxylic acid of the above.

As the method for producing the aliphatic polyester of the present invention, any method may be adopted. For example, the above aliphatic dicarboxylic acid [I
After esterification of I], it is reacted with about 2 molar equivalents of alkylene glycol [III] at 100 ° C to 250 ° C to produce an alkylene glycol adduct of an aliphatic dicarboxylic acid by dealcoholation, and then this adduct A method for producing an aliphatic polyester by deethylene glycol to react with the dihydroxy compound [I] at 200 ° C to 350 ° C,
Alternatively, a method of esterifying a constituent dicarboxylic acid [II] and then reacting with a diol component [[I] + [III]] to polymerize by dealcoholization, dicarboxylic acid [II]
Of the diol component [[I] + [III]] in a suitable solvent such as pyridine, and the metal alcoholate of the diol component [[I] + [III]] is a halogen of dicarboxylic acid [II]. Such as reacting with a compound
An aliphatic polyester can be produced by a conventionally known reaction between a carboxylic acid and an alcohol.

It is also possible to regulate the structure of the aliphatic polyester obtained by changing the order of addition of the dihydroxy compound during polymerization. For example, when the dihydroxy compound [I] is charged together with the aliphatic dicarboxylic acid [II] and the alkylene glycol [III], a random copolymer can be easily obtained, and the aliphatic dicarboxylic acid [II] and the alkylene can be obtained. When the dihydroxy compound [I] is charged in the latter stage of the polymerization after the reaction with the glycol [III], a block copolymer can be easily obtained. In addition, the previously synthesized aliphatic polyester is kneaded with the dihydroxy compound [I] or an acetylated product of the dihydroxy compound under reduced pressure heating, and a segment based on the dihydroxy compound [I] is introduced into the molecular chain by deethylene glycol or transesterification reaction. It is also possible to do so.

In the aliphatic polyester of the present invention, within a range that does not impair its practicality, in order to improve heat resistance, rigidity, etc., glass fibers, carbon fibers, whiskers, wollastonite and other reinforcing materials can be added up to 50% by weight. You may add in the range. In addition, stabilizers such as phosphite and flame retardants can be added.

The aliphatic polyester of the present invention is formed into a molded product by extrusion molding, injection molding, blow molding, etc., and the resulting molded product has excellent heat resistance, mechanical properties, etc., and is used in automobile parts, hoses, belts, packings and other industrial products. It is preferably used for molded products such as products.

(Examples) Hereinafter, the present invention will be described in detail based on examples.

In this example, 4,4 "-dihydroxy-p-terphenyl (DHT) was prepared by using 4-methoxy-4" -bromobiphenyl in Mg in tetrahydrofuran to prepare a Grignard reagent, which was converted to 4-bromoanisole. , As catalyst Ni
Coupling with Cl ₂ (dppp) led to the synthesis of 4,4 ″ -dimethoxybiphenyl, followed by PBr _{3 in} methylene chloride.
Was synthesized using

In addition, 4,4 "-di (2-hydroxyethoxy) -p-
Terphenyl (DHET) is 4,4 "-dihydroxy-p-
It was synthesized by reacting terphenyl with ethylene carbonate.

Example 1 <Synthesis of bis-2-hydroxyethyl adipate (BHEA)> 87.1 g (0.5 mol) of dimethyl adipate was placed in a glass flask having an internal volume of 1 equipped with a stirrer, a thermometer, a gas blowing port, and a distillation port. , Ethylene glycol 74.4g (1.2mo
l), a small amount of calcium acetate and a small amount of antimony oxide as a catalyst were added, and the inside of the flask was replaced with nitrogen, and then the temperature inside the flask was raised to react at 180 ° C. for 2 hours. As the reaction progressed, methanol began to distill from the flask, and bis-2
-Hydroxyethyl adipate formed.

<Synthesis of Aliphatic Polyester> To the flask described above, 16.9 g (0.05 mol) of 4,4 ″ -dihydroxy-p-terphenyl was added, the temperature of the flask was raised to 280 ° C., and the reaction was carried out at this temperature for 1 hour. Next, the distillation port was connected to a vacuum device, and the reaction was carried out for 2 hours while the pressure inside the flask was reduced to 1 mmHg.Ethin glycol was distilled out along with the reaction, and an extremely viscous liquid was formed inside the flask.

The melting point of the aliphatic polyester thus obtained was measured, and the results are shown in Table 1.

Example 2 In the same manner as in Example 1 except that 4,4 ″ -dihydroxy-p-terphenyl (DHT) and bis-2-hydroxyethyl adipate (BHEA) were mixed in the molar ratios shown in Table 1. An aliphatic polyester was obtained, and the melting point of the aliphatic polyester was measured and the results are shown in Table 1.

Example 3 Except that 4,4 ″ -di (2-hydroxyethoxy) -p-terphenyl (DHET) and bis-2-hydroxyethyl adipate (BHEA) were mixed in the molar ratios shown in Table 1,
An aliphatic polyester was obtained in the same manner as in Example 1. The melting point of the aliphatic polyester was measured, and the results are shown in Table 1.

Example 4 A glass flask having an inner volume of 1 equipped with a stirrer, a thermometer, a gas blowing port and a distillation port was charged with dimethyl adipate.
87.1g (0.5mol), butylene glycol 108.0g (1.2mo
l), a small amount of calcium acetate and a small amount of antimony oxide as a catalyst were added, and the inside of the flask was replaced with nitrogen, and then the temperature inside the flask was raised to react at 180 ° C. for 2 hours. With the reaction,
Methanol started to distill from the flask and bis-2-hydroxybutyl adipate was formed.

Next, the bis-2-hydroxybutyl adipate (BHBA) obtained above and 4,4 ″ -di (2-hydroxyethoxy) -p-terphenyl (DHET) were used in a molar ratio shown in Table 1. An aliphatic polyester was obtained in the same manner as in Example 1 except that the aliphatic polyester was blended, and the melting point of the aliphatic polyester was measured, and the results are shown in Table 1.

Comparative Example 1 The melting point of bis-2-hydroxyethyl adipate (BHEA) alone was measured, and the results are shown in Table 1.

Comparative Examples 2 and 3 Melting points of commercially available Perprene S-9001 manufactured by Toyobo Co., Ltd. and Hytrel 7247 manufactured by Toray DuPont were measured, and the results are shown in Table 1.

From the results in Table 1, the aliphatic polyester containing the dihydroxy compound in the molecular chain has a higher melting point than the polymer containing no dihydroxy compound (Comparative Example 1) or the commercially available thermoplastic elastomers (Comparative Examples 2 and 3). It can be seen that the heat resistance is excellent.

(Effect of the invention) The composition of the aliphatic polyester of the present invention is as described above, and the aliphatic polyester mainly composed of the aliphatic carboxylic acid and the alkylene glycol has high crystallinity,
Since a segment based on a dihydroxy compound having a high melting point is introduced, it has not only performance as a thermoplastic elastomer, but also excellent heat resistance, mechanical properties, molding processing properties, and the like.

Front page continued (72) Inventor Hiroki Kadomachi 7-20 Otemachi, Ibaraki City, Osaka Prefecture (72) Inventor Daishiro Kishimoto 2-11-20 Mishimaoka, Ibaraki City, Osaka Prefecture (56) References 61-241317 (JP, A) JP 62-70419 (JP, A) JP 2-1768 (JP, A) JP 47-25296 (JP, A) JP 48-29896 (JP, A) JP-A-50-90697 (JP, A)

Claims (1)

[Claims] 1. A dihydroxy compound represented by the following formula [I], an aliphatic dicarboxylic acid represented by the following formula [II], and an alkylene glycol represented by the following formula [III]. And an aliphatic polyester having as a main component, the dihydroxy compound is blended in a proportion of 0.1 to 30 mol% of a diol component formed by combining the dihydroxy compound and the alkylene glycol, and o-chloro An aliphatic polyester having an intrinsic viscosity of 0.4 or more and 2.0 or less as measured by an Ubbelohde viscometer using a dilute phenol solution at 30 ° C. (Wherein, R represents -H, or _{-CH 2 CH 2 OH) HOOC- (} CH 2) ( wherein, n an integer of 0) n-COOH [II] HO- (CH ₂₎ n -OH [III] (In the formula, n is an integer of 2 to 10)