JPH0826129B2 - Aromatic polyester - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aromatic polyester that is preferably used as a material for molded articles, fibers, films, paints, adhesives, and the like.

(Prior Art) Generally, an aromatic polyester is obtained by polycondensing an aromatic dicarboxylic acid and a dihydroxy compound.
For example, a polycondensate containing terephthalic acid and ethylene glycol is polyethylene terephthalate (PET).
Known as. Further, a polycondensate containing terephthalic acid and butylene terephthalate as constituent components is known as polybutylene terephthalate (PBT). These resins are excellent in mechanical properties, electrical properties, flame resistance, weather resistance, and chemical resistance.

However, since polyethylene terephthalate is slow to crystallize, when injection molding is performed using a normal mold that is heated with hot water and used at a temperature of 100 ° C or less, the resin does not crystallize in the mold. It has the drawbacks that it does not proceed sufficiently, the dimensional stability of the resulting molded product is poor, and the surface condition of the molded product is poor.

When polyethylene terephthalate is molded at a mold temperature of 130 ° C or higher, the above-mentioned problem of slow crystallization is solved, but in this case it is necessary to use a high-temperature mold, which is economically difficult. It is a disadvantage.

Therefore, various methods have been tried so far in order to improve the crystallinity of polyethylene terephthalate.

For example, by adding a plasticizing component or copolymerizing it, a method of activating movement between polymer molecules to promote molecular orientation for crystallization, or a method of adding a crystal nucleating agent to facilitate crystallization. is there.

Regarding the method of the above, Japanese Patent Publication No. 47-3027 and Japanese Patent Publication No.
47-4140 and Japanese Patent Application Laid-Open No. 57-38849 disclose a technique of introducing a flexible chain such as polyether glycol into the molecular chain of an aromatic polyester. However, this method cannot avoid deterioration in heat resistance and mechanical properties of the aromatic polyester.

Regarding the above method, JP-A-54-158452,
Japanese Patent Application Laid-Open No. 56-57825 and Japanese Patent Publication No. 54-38622 disclose a technique of adding a metal salt of an organic acid or a high melting point polyethylene terephthalate. However, the method of adding such an external nucleating agent has a limitation in promoting crystallization, and the crystallization cannot be said to be sufficiently fast.

Further, JP-A-55-82150 discloses a technique of adding specific liquid crystal molecules. However, with this method, the crystallization of the aromatic polyester is delayed. Further, Japanese Patent Application Laid-Open No. 56-104933 also discloses a method of binding a compound that gives a liquid crystal segment structure to a molecule, but even with this method, crystallization of an aromatic polyester cannot be said to be sufficiently fast.

On the other hand, since polybutylene terephthalate crystallizes faster than polyethylene terephthalate, a good molded product can be obtained even with a mold of 100 ° C. or lower. However, this polybutylene terephthalate is disadvantageous in that it has lower heat resistance and lower mechanical properties than polyethylene terephthalate.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and an object of the invention is to provide an aromatic polyester that is rapidly crystallized, and has improved heat resistance and mechanical properties. Is.

(Means for Solving the Problems) In the present invention, a segment based on a compound represented by the following formula [I] having high crystallinity and a melting point of 300 ° C. or higher is formed between the molecular chains of aromatic polyester molecules or at the terminals. The present invention has been completed by obtaining the knowledge that a resin excellent in heat resistance, which has a high crystallization rate and a high melting point, can be obtained by introducing it into the present invention.

That is, the aromatic polyester of the present invention contains a dihydroxy compound represented by the following formula [I], an aromatic dicarboxylic acid, and an alkylene glycol as main components, and the dihydroxy compound is the dihydroxy compound and the alkylene glycol. Is blended in a proportion of 0.1 to 30 mol% of the diol component which is combined with, and has an intrinsic viscosity of 0.4 or more and 4.0 or less by an Ubbelohde viscometer measured at 30 ° C. using a dilute solution of o-chlorophenol, Thereby, the above object is achieved.

(In the formula, R represents —H or —CH ₂ CH ₂ OH) The dihydroxy compound represented by the above formula [I] is a low-molecular compound exhibiting liquid crystallinity, and specifically, represented by the following formula [II ] And 4,4 "-dihydroxy-p-terphenyl represented by the formula] and 4,4" -di (2-hydroxyethoxy) -p-terphenyl represented by the following formula [III].

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. A resin can be obtained. These dihydroxy compounds may be used alone or in combination.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,
4 ″ -biphenyldicarboxylic acid and the like.

The alkylene glycol has the general formula HO- (CH ₂ ).
Those represented by n-OH (n is an integer of 2 to 10) are preferable,
For example, ethylene glycol, propylene glycol,
Butylene glycol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, hexamethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol and other aliphatic and alicyclic glycols Can be mentioned. An alkylene glycol having more than 10 carbon atoms may deteriorate the physical properties.

The dihydroxy compound [I] is preferably contained in an amount of 0.1 mol% to 30 mol% in the diol component obtained by combining the alkylene glycol and the dihydroxy compound [I]. When the content of the dihydroxy compound [I] in the diol component is less than 0.1 mol%, the crystallization rate of the obtained aromatic polyester is not sufficiently high,
Further, it is difficult to exhibit sufficient physical properties, particularly heat resistance. Further, even if the content of the dihydroxy compound [I] in the diol component is more than 30 mol%, not only the improvement in the crystallization rate of the aromatic polyester is not observed, but the cylinder temperature during injection molding is set to 300%. Since it is necessary to set the temperature above ℃, it tends to be disadvantageous in terms of moldability and raw material cost.

Any method can be adopted for producing the aromatic polyester. It can be obtained by reacting a diol component composed of a dihydroxy compound and an alkylene glycol with an aromatic carboxylic acid in an approximately equimolar ratio.

For example, the following method can be mentioned as a method for introducing a segment based on a dihydroxy compound into a polyethylene terephthalate molecule.

That is, after esterifying terephthalic acid, it is reacted with 2 molar equivalents of ethylene glycol at 100 ° C to 250 ° C,
Bishydroxyethyl terephthalate is synthesized by dealcoholization, and this is reacted with the above dihydroxy compound [I] at 200 ° C. to 350 ° C. to produce an aromatic polyester by a deethylene glycol reaction. Here, bishydroxyethyl terephthalate may be synthesized by direct esterification of terephthalic acid and ethylene glycol. Also, after acetylating the diol component,
A method of reacting with a dicarboxylic acid to polymerize by deacetic acid, a method of esterifying a dicarboxylic acid and then reacting with a diol component to polymerize by dealcoholization, a halide of dicarboxylic acid and a diol component in a suitable solvent such as polyzine. The aromatic polyester can be produced by a conventionally known reaction between a carboxylic acid and an alcohol, such as a reaction method or a method in which a metal alcoholate of a diol component is reacted with a dicarboxylic acid halide.

Further, a pre-synthesized polyethylene terephthalate is kneaded with a dihydroxy compound [I] or an acetylated product thereof under reduced pressure heating, and a segment based on the dihydroxy compound [I] is introduced into the molecular chain of polyethylene terephthalate by deethylene glycol or transesterification reaction. It is also possible to produce an aromatic polyester. The above method is applicable not only to polyethylene terephthalate but also to other aromatic polyesters. Some or all of the diol components of other aromatic polyesters such as polybutylene terephthalate may be represented by the formula [I]. An aromatic polyester having a high crystallization rate and improved heat resistance and mechanical properties can also be obtained by substituting the compound represented by

Further, in the aromatic polyester of the present invention, another dicarboxylic acid compound or another dihydroxy compound may be copolymerized in order to adjust mechanical properties and moldability. Other dicarboxylic acids include an alkyl group such as a methyl group and an ethyl group, an aromatic dicarboxylic acid having a substituent such as a halogen group such as a chloro group and a bromo group, 1,4-cyclohexanecarboxylic acid, and adipic acid. Alicyclic and aliphatic dicarboxylic acids such as suberic acid and sebacic acid. Examples of the dihydroxy compound include hydroquinone, resorcin, 4,4'-dihydroxybiphenyl, bisphenol A, 2,6-naphthalenediol and other dihydroxy compounds, and the above-mentioned aliphatic and alicyclic glycols. In addition, para-hydroxybenzoic acid, 4-hydroxy-4'-
Hydroxycarboxylic acids such as carboxybiphenyl and 2-hydroxy-6-naphthoic acid may be copolymerized.

The transition temperature from the crystal of the dihydroxy compound [I] to the liquid crystal state is 300 ° C. or higher, and the molecules are molten in the liquid crystal state, but the orientation of the molecules is maintained. By introducing a segment based on the dihydroxy compound [I] which is extremely easily crystallized into the molecular chain of the aromatic polyester, the crystallinity of the aromatic polyester is increased and various physical properties such as heat resistance are improved. It seems to be one. Further, since the transition temperature of the dihydroxy compound [I] is high, the crystallinity of the aromatic polyester is increased by introducing the dihydroxy compound [I] into the molecular chain of the aromatic polyester, and at the same time, the heat resistance is high. It is speculated that a resin can be obtained.

The aromatic polyester of the present invention, within a range not impairing its practicality, in order to improve heat resistance, rigidity, etc., 1 to 50% by weight of a reinforcing material such as glass fiber, carbon fiber, whiskers, and wollastonite. You can add up to a range of up to. Further, as a crystallization accelerator, talc, inorganic substances such as barium sulfate, alumina, and silicon oxide, higher fatty acid salts such as sodium stearate, barium stearate, and sodium palmitate, organic compounds such as benzyl alcohol, and benzophenone, or high crystals. A known nucleating agent such as polyethylene terephthalate or polytrans-cyclohexanedimethanol terephthalate may be added. Further, stabilizers such as phosphite, flame retardants, antistatic agents, and release agents may be added as desired.

Since the aromatic polyester of the present invention has a high crystallization rate, it is optimal as a molding material for various molded products. It can also be used in films, fibers, adhesives and paints. Further, the aromatic polyester of the present invention is mixed with another thermoplastic resin such as polyolefin, modified polyolefin, polystyrene, polyamide, polycarbonate, polysulfone, polyester, or the like, or is mixed with a rubber component to modify its properties. You may use it.

(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" -bromobienyl in Mg in tetrahydrofuran to prepare a Grignard reagent, which was treated with 4-bromoanisole. Ni as catalyst
Coupling with Cl ₂ (dppe) was used to synthesize 4,4 ″ -dimethoxybiphenyl, followed by PBr ₃ in methylene chloride.

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 97.1 g (0.5 mol) of dimethyl terephthalate was placed in a flask equipped with a stirrer, a thermometer, a gas blowing port and a distillation port.
74.5 g (1.2 mol) of ethylene glycol, calcium acetate and a small amount of antimony oxide as a catalyst were added, and after the inside of the flask was replaced with nitrogen, the temperature of the flask was raised and the reaction was carried out at 180 ° C. for 2 hours. With the reaction, methanol began to distill out from the flask, and bis-2-hydroxyethyl terephthalate (BHET) was produced.

To this flask, 25.4 g (0.075 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 about 1 hour. Next, the distillation port was vacuumed. It was connected to a vessel and reacted for 2 hours under a reduced pressure of 1 mmHg in the flask.Ethin glycol was distilled out along with the reaction, and an extremely viscous polymer was produced in the flask. Diameter 10 μm,
A glass fiber having a length of 3 mm was kneaded at 30% by weight to obtain a composition.

This composition is used in injection molding equipment (Toshiba Machinery Co., Ltd., IS
30EPN), cylinder temperature 270 ℃, nozzle temperature 265
℃, mold temperature 65 ℃, full cycle 23 seconds molding conditions, JIS
It was possible to continuously mold No. 1 type test pieces with K7113. The surface of the obtained test piece was smooth. When the tensile strength was measured using this test piece, the tensile strength was 19
It was 50 kg / cm ² . Further, when the heat distortion temperature (18.5 kg / cm ² ) of the test piece was measured according to JIS K7207, the heat distortion temperature was 257 ° C.

Comparative Example A polymer was obtained in the same manner as in Example 1 except that the dihydroxy compound (DHT) was not added. A glass fiber was added to the obtained polymer in the same manner as in Example 1 to obtain a composition.

When the moldability of the obtained composition was evaluated, crystallization of the composition was too slow, so that a test piece having good surface smoothness could not be obtained under the molding conditions of Example 1, and continuous molding was performed. I couldn't.

Examples 2 to 5 Polymers were obtained in the same manner as in Example 1 except that the composition of the aromatic polyester was changed as shown in Table 1.

Next, the crystallization rate of the aromatic polyester was evaluated by measuring the elevated temperature crystallization temperature of the sample obtained by rapidly cooling the obtained aromatic polyester. As a result, the exothermic peak of crystallization could be observed at 118 ° C. for the aromatic polyester obtained by polymerization without adding the dihydroxy compound, but the aromatic polyesters obtained in Examples 2-5 were completely No exothermic peak was seen. This suggests that the crystallization was already completed when the aromatic polyester was quenched.

Also, the isothermal crystallization half-life of the obtained aromatic polyester was measured. As a result, the aromatic polyester obtained by the polymerization without adding the dihydroxy compound had an isothermal crystallization half-life of 6 minutes and 40 seconds, whereas the samples of Examples 2 to 4 had extremely low isothermal crystallization half-lives as shown in Table 1. It was very short. Particularly in Example 4, the crystallization was so fast that the peak was absorbed in the baseline during quenching, and the accurate crystallization half-life could not be read. The results are shown in Table 1.

The elevated temperature crystallization temperature and the isothermal crystallization half-life were measured as follows.

Measurement of temperature rising crystallization temperature; the obtained aromatic polyester was dried in a vacuum oven at 110 ° C, and the aromatic polyester was pressed between the polytetrafluoroethylene-coated stainless steel plates at a pressure of 18 MPa and a temperature of 280 ° C. Thickness 0.375m
Got a film of m. Next, this film was pressed with a predetermined pressure for 2 minutes, and then the film was cooled in ice. A sample of about 10 mg was cut from this film, and the sample was heated at a rate of 16 ° C / min using a Perkin Elmer IB type flow calorimeter (DSC) to draw the exothermic peak of crystallization. The temperature was recorded.

Measurement of isothermal crystallization half-life; Using the above-mentioned flow calorimeter (DSC), the sample was melted at 270 ° C for 10 minutes and then rapidly cooled to 200 ° C. The crystallization exothermic peak was drawn while the temperature was kept at 1, and the time required to reach the half of the peak area was shown.

(Effect of the invention) The composition of the aromatic polyester of the present invention is as described above, and since the segment based on the dihydroxy compound is introduced between the molecular chains of the aromatic polyester molecule or at the terminal, crystallization is sufficiently fast. Moreover, an aromatic polyester having excellent mechanical properties and heat resistance can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroki Kakumachi, 7-20 Otemachi, Ibaraki-shi, Osaka (72) Inventor Daishiro Kishimoto 2-11-20, Mishimaoka, Ibaraki-shi, Osaka (56) References JP 62-70419 (JP, A) JP 61-241317 (JP, A) JP 2-1768 (JP, A) JP 54-158452 (JP, A) JP 55-82150 (JP, A)

Claims (1)

[Claims] 1. An aromatic polyester comprising a dihydroxy compound represented by the following formula [I], an aromatic dicarboxylic acid, and an alkylene glycol as main components, wherein the dihydroxy compound and the dihydroxy compound are It is blended in a proportion of 0.1 to 30 mol% of the diol component combined with alkylene glycol, and has an intrinsic viscosity of 0.4 or more and 4.0 or less by an Ubbelohde viscometer measured at 30 ° C using a dilute solution of o-chlorophenol. An aromatic polyester. (In the formula, R represents -H or -CH ₂ CH ₂ OH)