JPH0819322B2 - Polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a polyester resin comprising a thermotropic liquid crystalline phosphorus-containing polyester and another thermoplastic resin, which is excellent in heat resistance, flame retardancy and moldability. It relates to a composition.

(Prior Art) A wholly aromatic polyester (polyarylate) is conventionally known as a heat-resistant polymer. In general, wholly aromatic polyester has extremely high melting point and high melt viscosity at the same time even though it has excellent physical properties, and therefore it is extremely inconvenient to process at high temperature and high pressure. However, long-term exposure to high temperature is not a good idea from the viewpoint of polyester decomposition and is economically disadvantageous.

In recent years, thermotropic liquid crystalline polyester, which has excellent processability, has been attracting attention and is being actively researched.

However, the thermotropic liquid crystalline polyesters that have been proposed hitherto have insufficient melt processability, heat resistance, and flame retardancy.

On the other hand, thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate, and polycarbonate are
It is widely used as an engineering plastic with good moldability, but the required performance is increasing year by year, and problems such as insufficient heat distortion resistance and flame retardancy have arisen.

In addition, blending of other polymers has been attempted for the purpose of improving the moldability and mechanical properties of the thermotropic liquid crystalline polyester. For example, a thermotropic liquid crystalline polyester having a 2,6-naphthalene group has been used. It has been proposed to blend polyalkylene terephthalate, polycarbonate, etc. (JP-A-57-25234, 57
-44551). However, although such a composition improves moldability and mechanical properties to some extent, it is not sufficient and flame retardancy is not improved at all.

As a solution to such a problem, the present inventors previously proposed a composition comprising a specific thermotropic liquid crystalline phosphocopolyester and another thermoplastic resin (Japanese Patent Laid-Open No. 62-265341). ).

However, the copolyester in this composition has a problem that the raw material phosphorus-containing aromatic diol is expensive.

(Problems to be Solved by the Invention) The present invention solves the drawbacks of conventional thermoplastic resins as thermotropic liquid crystalline polyesters and engineering plastics, and has excellent moldability and good heat resistance,
Moreover, it is intended to provide a polyester resin composition having high flame retardancy at low cost.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have found that a composition of a phosphocopolyester containing a thermotropic liquid crystallinity having a specific structure and another thermoplastic resin. The present invention has been accomplished by finding that it is effective to use the product.

 That is, the gist of the present invention is as follows.

It mainly consists of structural units represented by the following structural formulas, and the molar ratios of the units are substantially equal to and,
And are 5/95 to 95/5 and consist of a thermotropic liquid crystalline random copolyester with an intrinsic viscosity of 0.5 or more and a thermoplastic resin selected from polyethylene terephthalate, polybutylene terephthalate and polycarbonate, the former being a composition Of the polyester resin composition, which occupies 8 to 80% by weight.

—OC—Ar ² —CO— —O—Ar ³ —CO— [Ar ¹ represents a trivalent aromatic group, and Ar ² and Ar ³ represent a divalent aromatic group. However, the aromatic ring may have a substituent. ] As the Ar ^{1 in the} formula, a benzene ring and a naphthalene ring are most preferable. Further, in the formula, the hydrogen atom of the aromatic ring may be substituted with an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, an aryloxy group or a halogen atom.

Specific examples of the aromatic diol forming the unit of the formula include those represented by the following formulas (a) to (d),
Particularly preferred are those represented by formula (a) and formula (b).

Further, as specific examples of the aromatic dicarboxylic acid forming the unit of the formula, terephthalic acid and isophthalic acid are preferable, and the molar ratio of terephthalic acid and isophthalic acid is 100/0.
~ 0/100, preferably 100/0 to 50/50, optimally 100/0 to 70/3
It is suitable to use it at a ratio of 0.

In addition to terephthalic acid and isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl, 2,2-
Bis (4'-carboxyphenyl) propane, bis (4
-Carboxyphenyl) methane, bis (4-carboxyphenyl) ether and the like can also be used.

Furthermore, specific examples of the aromatic hydroxycarboxylic acid forming the unit of the formula include 4-hydroxybenzoic acid, 4-hydroxy-3-phenylbenzoic acid, 4-hydroxy-3-
Chlorobenzoic acid, 2-hydroxy-6-naphthoic acid and 1
-Hydroxy-4-naphthoic acid and the like can be mentioned, but the most preferable one is 4-hydroxybenzoic acid.

In the copolyester of the present invention, the ratio of each constitutional unit is substantially equal to the unit in molar ratio,
The unit is 5/95 to 95/5, preferably 20/80 to 70/30, most preferably 30/70 to 50/50.

A copolyester having a high degree of polymerization cannot be obtained unless the units are substantially equimolar. On the other hand, if the proportion of the units is too large, the strength of the molded product will be lowered, while if the proportion of the units is too small, the melting point will be too high or the flame retardancy will be lowered, which is not preferable.

In addition, components other than the above may be copolymerized within the range of forming a thermotropic liquid crystalline copolyester having good melt moldability. Examples of such copolymerization components include hydroquinone, resorcin, 1,4-naphtho Hydroquinone, 2,6
-Naphthohydroquinone, 4,4'-dihydroxydiphenyl, 2,2-bis (4'-hydroxyphenyl) propane,
Bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, ethylene glycol, 1,4
Examples include cyclohexanedimethanol, pentaerythritol, 1,4-cyclohexanedicarboxylic acid, adipic acid and trimellitic acid.

Next, an example of the method for producing the copolyester in the present invention will be described.

(A) The amount of phosphorus acetate-containing aromatic diol diacetate, aromatic dicarboxylic acid, and aromatic hydroxycarboxylic acid acetate is such that the hydroxyl residue and the carboxyl group are equivalent (and preferably 0.01% of the total hydroxyl group).
To 0.25 equivalent of acetic anhydride) or (b) phosphorus-containing aromatic diol, aromatic dicarboxylic acid and aromatic hydroxycarboxylic acid in an amount of 1.05 to 1.25 of the amount in which hydroxyl groups and carboxyl groups are equivalent and the total amount of hydroxyl groups. A double equivalent of acetic anhydride is charged into the reactor, and the esterification reaction or acid exchange reaction is carried out at a temperature of about 140 ° C for about 2 hours under normal pressure. After that, raise the temperature sequentially, distill acetic acid while reducing the pressure if necessary, and raise the temperature to about 280 ° C. Then finally normal, 2
A thermotropic liquid crystalline copolyester can be obtained by carrying out a polycondensation reaction in a melt phase or a solid phase at a temperature of 80 to 320 ° C. under a high reduced pressure of less than 1 torr for several tens of minutes to several hours.

Usually, a catalyst is used in the polycondensation reaction, but in the production of the copolyester in the present invention, one or more kinds of compounds selected from various metal compounds and organic sulfonic acid compounds are used.

As the metal compound, compounds such as antimony, titanium, germanium, tin, zinc, aluminum, magnesium, calcium, manganese, sodium or cobalt are used, while as the organic sulfonic acid compound, sulfosalicylic acid, o-sulfobenzoic acid are used. A compound such as an anhydride is used. Particularly preferred are dimethyltin maleate and o-sulfobenzoic anhydride.

The amount of the catalyst added is usually 0.1 × 10 ^{-4 to} 100 × 10 ^-4 mol, preferably 0.5, per 1 mol of the polyester repeating unit.
X10 ^-4 to 50 X 10 ^-4 mol, optimally 1 X 10 ^-4 to 10 X 10 ^-4 mol are suitable.

The copolyester of the present invention has an intrinsic viscosity [η]
It is necessary to be 0.5 or more, preferably 1.0 to 10.
0, optimally 3.0-6.0. When [η] is smaller than this range, various physical and mechanical properties such as heat resistance are inferior, while when [η] is larger than this range, melt viscosity becomes high and fluidity is impaired. Undesirably, the melting point becomes too high and the molding temperature must be raised significantly.

The thermal characteristic value of the copolyester according to the present invention is such that the flow initiation temperature is 330 ° C. or lower, preferably 240 to 28.
A temperature of 0 ° C. and a heat distortion temperature of 155 ° C. or higher, preferably 160 to 220 ° C. are suitable from the viewpoint of achieving both heat resistance and various physical and mechanical property values.

Next, the thermoplastic resin to be blended with the thermotropic liquid crystalline copolyester may be any one that improves the moldability of the thermotropic liquid crystalline copolyester, and can be crystalline, amorphous, or thermotropic liquid crystalline. However, a material that does not have thermotropic liquid crystallinity is usually used.

In the present invention, as such a thermoplastic resin, polyethylene terephthalate, polybutylene terephthalate (including a copolymer containing them as a main component) and polycarbonate are preferably used.

As the polycarbonate, 4,4'-dioxydiallyl alkane-based polycarbonate is particularly preferable, and examples thereof include bis (4-hydroxyphenyl) methane and bis (4
-Hydroxyphenyl) ethane, 2,2-bis (4'-hydroxyphenyl) propane, bis (4-hydroxy-3,
4,4 'such as 5-dichlorophenyl) methane, 2,2-bis (4'-hydroxy-3', 5'-dimethylphenyl) propane, bis (4-hydroxyphenyl) phenylmethane
A polycarbonate obtained from dihydroxydiphenylalkane and phosgene or diphenylcarbonate is preferably used.

The ratio of the thermotropic liquid crystalline copolyester and the thermoplastic resin should be 8 to 80% by weight of the composition, preferably 20 to 80% by weight, and optimally 50 to 80% by weight. . If the amount of copolyester is too large, the strength of the molded product will decrease, while if it is too small, the glass transition temperature will be low and the flame retardancy will be insufficient, which is not preferable.

To obtain a composition by mixing the thermotropic liquid crystalline copolyester and another thermoplastic resin, both components are uniformly mixed by a solution blending method or a mixing method using a two-roll, Banbury mixer, melt extruder or other mixer. Can be mixed with.

(Function) The reason why the composition of the present invention has high heat resistance and excellent moldability is not clear, but it is easy to use the thermotropic liquid crystalline copolyester excellent in heat resistance and the thermoplastic resin. It is presumed that a composition having thermotropic liquid crystallinity was obtained by uniformly mixing the two with each other, and the excellent physical properties of both were synergized.

Further, since the copolyester in the present invention is an aromatic copolyester containing a phosphorus atom, it exhibits high flame retardancy.

(Example) Next, the present invention will be described in more detail with reference to examples.

 The measuring method of the characteristic value is as follows.

Intrinsic Viscosity [η] It was calculated from the solution viscosity measured at 20 ℃ using an equal weight solvent mixture of phenol and ethane tetrachloride.

Flow starting temperature Tf Using a flow tester (CTF-500 type manufactured by Shimadzu Corporation),
Under the conditions of a load of 100 kg / cm ² , a nozzle diameter of the die of 0.5 mm, and a length of 2.0 mm, the temperature was raised from the initial temperature of 200 ° C at a heating rate of 10 ° C / min, and the temperature was calculated as the temperature at which the polymer began to flow.

Heat distortion temperature Measured under a large load according to HDT ASTM D648.

Bending strength and flexural modulus A test specimen with a thickness of 1/8 inch was measured according to the ASTM D790 standard.

Izod impact strength Measured according to IZ ASTM D256 standard with a thickness of 1/8 inch and a notch. (Unit: kgf · cm / cm) Flame retardant For samples with a thickness of 1/16 inch, flame retardant class (HB, V-2, V-1, V-0) according to UL-94 standard and JIS K 7201 The limiting oxygen index (LOI) according to the standard was determined.

Formability Using a J-100-S type injection molding machine manufactured by Japan Steel Works, 100φ
A 1/8 inch disk-shaped test piece was molded and evaluated according to the following criteria according to the conditions at that time.

◎: Injection time is 10 seconds or less and molding temperature is 330 ° C or less ○: Injection time is 10 to 15 seconds and molding temperature is less than 330 ° C △: Injection time is 15 to 30 seconds and molding temperature is Less than 330 ℃ ×: Injection time is 30 seconds or more or molding temperature is 330 ℃ or more. Thermotropic liquid crystal property is with hot stage.
Confirmed with a Leitz polarization microscope.

Examples 1 to 9 The aromatic diol (PPQ), 4 of the above formula (a) was added to the reactor.
-Hydroxybenzoic acid (4HBA) and acetic anhydride in molar ratio
Charge terephthalic acid (TPA) equimolar to 35/65/145 and PPQ, add dimethyltin maleate as catalyst to 4 × 10 ^-4 mol per 1 mol of polyester repeating unit, and under nitrogen atmosphere at atmospheric pressure, The mixture was reacted at 140 ° C. for 2 hours while mixing. This reaction product was further subjected to 280 at 240 ° C. for 2 hours under normal pressure.
The reaction was performed at 0 ° C for 2 hours. Then gradually reduce this pressure to 0.
Under a reduced pressure of 1 torr, the temperature is raised sequentially to carry out the reaction, and finally 320
The temperature was raised to 0 ° C. and melt polymerization was performed at that temperature for 3 hours.

The obtained copolyester has [η] 2.1, Tf253 ℃, LOI6
It was 3, and was a liquid crystalline copolyester with a good color tone.

After thoroughly mixing this copolyester with polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT) or polycarbonate resin (PC) in the proportion shown in Table 1, screw type melting with a 4 mm diameter die attached to the tip It is supplied to an extruder (screw diameter 30 mm, L / D20), and is extruded in a strand at a processing temperature according to the composition at a screw rotation speed of 30 rpm, cooled, and then cut into a length of 3 mm to obtain granules. It was

Table 1 shows the results of measuring the physical properties by molding 1/8 × 1/8 × 5 (inch) sample pieces using this granular material.

As Comparative Examples 1 to 3, the results of molding each of the above resins alone are shown in Table 1.

Examples 10 to 12 Instead of PPQ in Example 1, the above formula (b),
Table 2 shows the physical properties of test pieces obtained in the same manner as in Example 1 except that the aromatic diols (c) and (d) were used.

Comparative Examples 4 to 5 Example 1 using PPQ, TPA, isophthalic acid (IPA) and 4HBA as a charge molar ratio of 99/90/9 / (Comparative Example 4) or 1/1/0/99 (Comparative Example 5). The same experiment as in Example 1 was conducted using a copolyester having no thermotropic liquid crystallinity obtained in the same manner as in.

In Comparative Example 4, it could not be uniformly mixed with PET, and in Comparative Example 5, the melting point and melt viscosity of the copolyester became too high, and molding was not possible with a general-purpose molding machine.

(Effects of the Invention) According to the present invention, the high heat resistance and flame retardancy of the phosphorus-containing thermotropic liquid crystalline copolyester and the excellent moldability of the thermoplastic resin are exhibited in a well-balanced manner, and are useful as engineering plastics. Provided is a polyester resin composition having excellent heat resistance, flame retardancy, and good moldability.

And since the phosphorus-containing thermotropic liquid crystalline copolyester becomes cheaper than the conventional one, the cost can be reduced.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP 62-265341 (JP, A) JP 55-5916 (JP, A) JP 53-128195 (JP, A) JP 49- 18145 (JP, A) JP 64-66195 (JP, A) JP 63-313795 (JP, A)

Claims (2)

[Claims] 1. A constitutional unit represented by the following structural formulas (1) to (5) is mainly used, and the molar ratio of each unit is substantially equal to and, and and are 5/95 to 95/5, and the intrinsic viscosity is 0.5
A polyester resin composition comprising the above thermotropic liquid crystalline random copolyester and a thermoplastic resin selected from polyethylene terephthalate, polybutylene terephthalate and polycarbonate, the former occupying 8 to 80% by weight of the composition. —OC—Ar ² —CO— —O—Ar ³ —CO— [Ar ¹ represents a trivalent aromatic group, and Ar ² and Ar ³ represent a divalent aromatic group. However, the aromatic ring may have a substituent. ] 2. The copolyester Ar ¹ is And Ar ² and Ar ³ are The polyester resin composition according to claim 1, which is