JPH0693173A - Liquid crystal polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition excellent in and well-balanced among mechanical properties, heat resistance, moldability into a thin-wall product, dimensional accuracy and slidability by mixing a polyester which forms an anisotropic molten phase with a specified scaly or flaky graphite. CONSTITUTION:The composition is prepared by kneading 100 pts.wt. liquid crystal polyester comprising structural units of formulas I, II and IV or of formulas I, II, III and IV and forming an anisotropic molten phase with 1-100 pts.wt. scaly graphite and/or flaky graphite each having a fixed carbon atom content of 95%, a mean particle diameter of 1-10mum, a specific surface area of 5-15m<2>/g and a lamella spacing of crystal of 350Angstrom or above. In the formulas, R1 is a group of formula V or VI or the like; R2 is a group of formula VII or VIII or the like; X is II or Cl; and the amount of structural units of formulas II and III is equimolar to that of structural units of formula IV.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal polymer resin composition having excellent mechanical properties, heat resistance, thin-wall moldability, dimensional accuracy and slidability, and having balanced performance for giving a good molded product. More specifically, a liquid crystal polyester resin composition having excellent sliding properties such as fluidity during molding of a thin molded product and dimensional accuracy of the molded product, and extremely small degree of damage to a soft metal such as an aluminum alloy during sliding. Regarding goods, electrical / electronic / electrical equipment related parts, automobile related parts,
The present invention relates to a liquid crystal polyester resin composition suitable for use in precision machinery-related parts, acoustic-related parts, optical fiber-related parts, OA equipment-related parts, chemical device-related parts, and the like.

[0002]

2. Description of the Related Art In recent years, demands for higher performance of plastics have been increasing, and many polymers having various new properties have been developed and put on the market. Among them, optics characterized by parallel arrangement of molecular chains Attention has been paid to anisotropic liquid crystal polymers because they have excellent fluidity and mechanical properties.
As the polymer forming these anisotropic melt phases, for example, liquid crystal polyester obtained by copolymerizing p-hydroxybenzoic acid with polyethylene terephthalate (Japanese Patent Laid-Open No. 49-7239).
3), a liquid crystal polyester obtained by copolymerizing p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid (Japanese Patent Laid-Open No. 54-77691), and p-hydroxybenzoic acid containing 4,4′-dihydroxy. A liquid crystal polyester obtained by copolymerizing biphenyl with terephthalic acid or isophthalic acid (Japanese Patent Publication No. 57-24407) is disclosed.

[0003]

However, these liquid crystal polymers have a low mechanical strength in the direction perpendicular to the flow direction and a high molding shrinkage, that is, mechanical anisotropy and dimensional anisotropy. It is known to have drawbacks such as being very large. It is also known that these liquid crystal polymers have a large dynamic friction coefficient because the molecular chains are easily oriented and form fibrils, and thus there is a problem in slidability.

As a method for improving these drawbacks, in JP-A-61-2185249, an attempt was made to improve slidability by compounding a liquid crystal polymer, a fibrous filler and a solid lubricant together for a gear. However, although the mechanical strength was improved, the slidability was not always sufficient. Also,
Japanese Unexamined Patent Publication (Kokai) No. 63-146959 discloses a composition in which a plate-like powder and a fibrous substance are used in combination with a liquid crystal polymer, but this composition is improved in anisotropy and mechanical strength to some extent. However, the slidability was still unsatisfactory due to some problems.

Therefore, the present invention solves the above-mentioned problems, is excellent in mechanical properties, heat resistance, thin-wall moldability, dimensional accuracy and slidability, and has a balanced liquid crystal polyester resin which gives excellent molded products. It is an object to obtain a composition.

[0006]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the present invention provides (A) the following structural units [(I), (II) and (IV)] or [(I), (II), (III) and (IV)
], And (B) fixed carbon is 95% or more, the average particle size is 1 to 10 μm, and the specific surface area is 5 with respect to 100 parts by weight of the liquid crystal polyester forming the anisotropic molten phase.
~15m a ² / g, there is provided a lamellar spacing of the crystal obtained by kneading 1 to 100 parts by weight flake graphite and / or scaly graphite is 350 angstroms or more liquid crystal polyester resin composition.

[0007] (However, R1 in the formula is

[0008] R1 represents one or more groups selected from

[0009] Represents one or more groups selected from Further, in the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (II
I)] and structural unit (IV) are substantially equimolar. The liquid crystal polyester referred to in the present invention is a polyester that forms an anisotropic melt phase, an aromatic oxycarbonyl unit,
A polyester comprising a structural unit selected from aromatic dioxy units, aromatic dicarbonyl units, ethylenedioxy units and the like, and the structural unit (I) is a structural unit of a polyester produced from p-hydroxybenzoic acid. (II) is 4,4'-dihydroxybiphenyl, 3,3 ',
5,5'-tetramethyl-4,4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis
A structural unit formed from an aromatic dihydroxy compound selected from (4-hydroxyphenyl) propane and 4,4′-dihydroxydiphenyl ether is represented by a structural unit (II
I) is a structural unit produced from ethylene glycol, and structural unit (IV) is terephthalic acid, isophthalic acid, 4,4′-biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane. Each of the structural units formed from an aromatic dicarboxylic acid selected from -4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and diphenyl ether dicarboxylic acid is shown. Of these, R1

[0010] And R2 is

[0011] Are preferred. The liquid crystal polyester of the present invention is
The above structural units (I), (II), (IV) or (I), (II), (I
II), a copolymer consisting of (IV), the above structural unit
The copolymerization amounts of (I), (II), (III) and (IV) are arbitrary. However, from the viewpoint of fluidity, the following copolymerization amount is preferable.

That is, when the structural unit (III) is contained, the structural unit [(I) + (II)] is [(I) + (II)] in view of heat resistance, flame retardancy and mechanical properties. + (III)]
60 to 95 mol% is preferable, and 82 to 92 mol% is more preferable. Further, the structural unit (III) is [(I) + (II)
+ (III)] is preferably 40 to 5 mol%, more preferably 18 to 8 mol%. The molar ratio of the structural unit (I) / (II) is preferably 7 from the viewpoint of the balance between heat resistance and fluidity.
5/25 to 95/5, more preferably 78/22
~ 93/7. The structural unit (IV) is substantially equimolar to the structural unit [(II) + (III)].

On the other hand, when the structural unit (III) is not contained, the structural unit (I) is [(I) + (I
I)] is preferably 40 to 90 mol%, and 60
It is particularly preferable that the content of the structural unit (I
V) is substantially equimolar to the structural unit (II). In addition,
In the polycondensation of the liquid crystal polyester which can be preferably used in the present invention, in addition to the components constituting the structural units (I) to (IV), 3,3'-diphenyldicarboxylic acid, 2,2'-
Aromatic dicarboxylic acids such as diphenyldicarboxylic acid, adipic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone,
Aromatic diols such as methylhydroquinone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl Aliphatic and alicyclic diols such as glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and p-amino Phenol, p-aminobenzoic acid and the like can be further copolymerized in a small proportion within a range that does not impair the object of the present invention.

The method for producing the above-mentioned liquid crystal polyester which can be preferably used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method. For example,
In the production of the liquid crystal polyester preferably used above, the following production methods (1) and (2) are preferable when the structural unit (III) is not contained, and the following production method (3) is preferable when the structural unit (III) is contained. .

(1) p-acetoxybenzoic acid and 4,
A method for producing a diacylated aromatic dihydroxy compound such as 4′-diacetoxybiphenyl or paraacetoxybenzene and an aromatic dicarboxylic acid such as terephthalic acid by a deacetic acid polycondensation reaction. (2) p-Hydroxybenzoic acid and 4,4′-dihydroxybiphenyl, aromatic dihydroxy compounds such as hydroquinone, aromatic dicarboxylic acids such as terephthalic acid are reacted with acetic anhydride to acylate the phenolic hydroxyl group, A method for producing by deacetic acid polycondensation reaction.

(3) In the presence of a polyester polymer such as polyethylene terephthalate, an oligomer or a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid such as bis (β-hydroxyethyl) terephthalate.
A method of manufacturing by the method of (1) or (2). Although these polycondensation reactions proceed without a catalyst, it is sometimes preferable to add a metal compound such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, or magnesium metal.

Some of the above-mentioned liquid crystal polyesters which can be preferably used in the present invention can measure the logarithmic viscosity in pentafluorophenol, and in that case, 0.1 g is used.
The value measured at 60 ° C at a concentration of / dl is preferably 0.5 or more, and particularly 1.0 to 3.0 when the above structural unit (III) is contained.
0 dl / g is preferable, and when the above structural unit (III) is not included, 2.0 to 10.0 dl / g is preferable.

The liquid crystal polyester of the present invention has a melt viscosity of preferably 10 to 20,000 poise, more preferably 20 to 10,000 poise. The melt viscosity is a value measured by a Koka flow tester under the conditions of melting point (Tm) + 10 ° C. and shear rate of 1,000 (1 / sec). Here, the melting point (Tm) is Tm1 + 20 ° C. after the observation of the endothermic peak temperature (Tm1) observed in the differential calorimetric measurement when the polymerization completed polymer is measured under the temperature rising condition from room temperature to 20 / min. After holding at the temperature of 5 minutes for 5 minutes, the temperature was once cooled to room temperature under the temperature lowering condition of 20 ° C./minute, and then the endothermic peak temperature (Tm2) observed when measured again under the temperature rising condition of 20 / minute was measured.

The scale-like graphite and / or scale-like flake graphite (B) used as an essential component of the present invention means that fixed carbon is 95%.
It is necessary to be above, and 97% or more is preferable.
If the fixed carbon content is less than 95%, sufficient sliding properties cannot be obtained. Further, the average particle diameter is required to be 1 to 10 μm, preferably 4 to 7 μm. If the average particle diameter is less than 1 μm, aggregation occurs and the dispersion becomes poor, and if it exceeds 10 μm, mechanical properties are deteriorated, which is not preferable. Further, the specific surface area needs to be 5 to 15 m ² / g, and 7-1
0 m ² / g is preferred. When the specific surface area is less than 5 m ² / g,
There is a large difference in shrinkage between the flow direction and the right angle direction of the molded product.
If it exceeds 5 m ² / g, fluidity may be impaired and a thin-walled molded product may not be obtained, which is not preferable.

Here, the specific surface area is measured by the BET method, and the adsorption amount (Vm) required for monomolecular formation from the adsorption isotherm.
Was calculated and the specific surface area (Σ) was calculated by the following formula. Σ = S × (Vm / 22400) × 6.02 × 10 ²³ (where S is the cross-sectional area of adsorbed molecules) The amount of the above-mentioned scaly graphite and / or scaly graphite (B) added is 100 1 to parts by weight
It is 100 parts by weight, preferably 5 to 50 parts by weight. If the addition amount is less than 1 part by weight, the effect of improving the wear resistance cannot be expected, and if it exceeds 100 parts by weight, not only the appearance of the molded article is impaired but also the mechanical properties are deteriorated, which is not preferable.

The lamella spacing of the crystal obtained by X-ray analysis is required to be 350 angstroms or more, preferably 400 angstroms or more, and more preferably 500 angstroms or more. If the lamellar spacing of the crystals is 350 angstroms or less, the mechanical properties of the composition, particularly the flexural modulus will be reduced, which is not preferable.

The surface of the scaly graphite and / or flake graphite (B) used in the present invention is treated with a known coupling agent (eg, silane coupling agent, titanate coupling agent) or the like. Can also be used. In the present invention, scaly graphite and / or scaly graphite
By adding a specific amount of (B), the anisotropy of the molding shrinkage can be reduced, and the fluidity is extremely good, so that thin-wall molding can be performed. Further, since the crystallinity is high, the mechanical properties, especially the bending elastic modulus are improved, and other mechanical properties are also improved in balance.

Further, a reinforcing agent and a filler can be used together in the composition of the present invention. Examples of these reinforcing agents and fillers are glass fiber, carbon fiber, aromatic polyamide fiber, potassium titanate fiber, gypsum fiber, brass fiber,
Fibers such as stainless steel fiber, steel fiber, ceramics fiber, boron whisker fiber, asbestos fiber, mica, talc, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, wollastonite, titanium oxide, molybdenum disulfide, etc. Inorganic fillers in the form of powder, powder, granules or plates are included.
As the filler and the reinforcing agent, those treated with a silane-based or titanate-based coupling agent or other surface treatment agent may be used.

Further, the resin composition of the present invention contains an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, and the like) to the extent that the object of the present invention is not impaired.
Phosphites and their substitution products), UV absorbers (eg resorcinol, salicylate, benzotriazole, benzophenone, etc.), lubricants and mold release agents (montanic acid and its salts, their esters, their half esters, stearic alcohol, stearamide) And polyethylene wax), dyes (eg nigrosine) and pigments (eg cadmium sulfide, phthalocyanine, carbon black etc.), conventional additives such as colorants, plasticizers, flame retardants, flame retardant aids, antistatic agents, etc. Or other thermoplastic resin (fluorine resin, etc.) is added,
It is possible to impart predetermined characteristics.

The resin composition of the present invention is preferably produced by melt kneading, and known methods can be used for melt kneading. For example, using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, and the like, the composition can be melt-kneaded at a temperature of 200 to 400 ° C to obtain a composition.

[0026]

EXAMPLES The present invention will be described in more detail with reference to Examples below. Reference Example 1 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4′-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0. 216 parts by weight of 6 dl / g polyethylene terephthalate and 960 parts by weight of acetic anhydride were charged into a reaction vessel equipped with a stirring blade and a distillation tube, and deacetic acid polymerization was carried out under the following conditions.

First, 130 to 250 in a nitrogen gas atmosphere.
After reacting at 50 ° C for 5 hours and at 250 to 300 ° C for 1.5 hours, the pressure was reduced to 0.5 mmHg at 320 ° C for 1 hour, and further 1.
When the reaction was carried out for 00 hours to complete the polycondensation, almost the theoretical amount of acetic acid was distilled out, and a resin having the following theoretical structural formula was obtained.
(a) was obtained.

[0028]

The polyester was placed on the sample stage of a polarizing microscope and the temperature was raised to confirm the optical anisotropy.
The liquid crystal starting temperature was 293 ° C., which showed good optical anisotropy. The melting point (Tm) was 314 ° C. The logarithmic viscosity of this polyester (measured in pentafluorophenol at a concentration of 0.1 g / dl at 60 ° C.) is 1.98 dl /
and the melt viscosity at 324 ° C. and the shear rate of 1000 / sec was 400 poise. Reference Example 2 p-Hydroxybenzoic acid 994 parts by weight, 4,4'-dihydroxybiphenyl 222 parts by weight, 2,6-diacetoxynaphthalene 147 parts by weight, acetic anhydride 1078 parts by weight, terephthalic acid 299 parts by weight, stirring blades and outflow After charging into a reaction vessel equipped with a tube and reacting under a nitrogen gas atmosphere at 130 to 250 ° C. for 5 hours and at 250 to 333 ° C. for 2.5 hours,
When the pressure was reduced to 1.0 mmHg in 1.5 hours at 335 ° C. and the reaction was further continued for 0.75 hours to complete polycondensation, a theoretical amount of acetic acid was distilled out, and a resin having the following structural formula was obtained.
(b) was obtained.

[0030]

When this polyester was placed on a sample stage of a polarizing microscope and the temperature was raised to check the optical anisotropy, good optical anisotropy was exhibited at 296 ° C. or higher. The melting point (Tm) was 323 ° C. The logarithmic viscosity of this polyester (measured under the same conditions as in Reference Example 1) was 4.9.
dl / g, and the melt viscosity at 333 ° C. and shear rate of 1000 / sec was 520 poise. Reference Example 3 "Vectra" A950 (Hoechst Celanese)
(C) The liquid crystal polyester had a liquid crystal onset temperature of 251 ° C. and a melting point (Tm) of 283 ° C. The melt viscosity is 18
It was 00 poise. Examples 1-6, Comparative Examples 1-5 Liquid crystalline polyester (A) obtained in Reference Example 1, scaly graphite
(B) was fed to a 30 mmφ twin-screw extruder set at 310 to 325 ° C. to be melted, fed at a ratio shown in Table 1 and further melt-kneaded to form pellets. The pellets were subjected to a Sumitomo Nestal injection molding machine Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions of a cylinder temperature of 325 ° C and a mold temperature of 90 ° C. 5x
125 mm) and 30 × 30 × 3.2 mm square plates were molded.

The bending elastic modulus of the obtained bending test piece was measured by Tensilon UTM4-200 type (manufactured by Toyo Baldwin Co., Ltd.).
Was measured using. Further, using a 30 × 30 × 3.2 mm square plate, a thrust wear tester (Suzuki wear tester) was used to perform a wear test under the following conditions to evaluate slidability. P = 5 kgf / cm ² , V = 20 m / min Mating material: Aluminum alloy 5056 Also, with a cylinder temperature of 325 ° C. and a mold temperature of 90 ° C., a film gate was provided on one side of a square plate 70 × 70 ×
A square plate with a thickness of 2 mm is formed, and after the formation, the flow direction of the square plate
Mold shrinkage in (MD) and right-angle direction (TD) is measured, and | Mold shrinkage in right-angle direction (TD) |-| Flow direction
The anisotropy was evaluated by obtaining the molding shrinkage ratio | of (MD).

The liquid crystalline polyester of Reference Example 2 (b)
When was used, the extruder temperature was 325 to 340 ° C., and the molding temperature was 340 ° C. In addition, "Vectra" A950 of Reference Example 3 (manufactured by Hoechst Celanese)
When (c) was used, the extruder temperature was 280 to 290 ° C and the molding temperature was 290 ° C. The results are also shown in Table 1.

[0034] From Table 1, it is apparent that the molded product obtained from the liquid crystal polyester resin composition of the present invention has small anisotropy, is excellent in thin-wall moldability, and is superior in slidability as compared with Comparative Examples.

[0035]

The liquid crystal polyester resin composition of the present invention has excellent mechanical properties and heat resistance, and in particular, is excellent in thin-wall moldability and slidability, and has small anisotropy and excellent dimensional accuracy. For example, sensors, LEP lamps, connectors, sockets, resistors, relay case switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards,
Transformer, plug, printed circuit board, tuner, speaker, microphone, headphones, small motor, magnetic head base, power module, semiconductor, liquid crystal, F
Electric / electronic parts such as DD carriage, FDD chassis, motor brush holder, parabolic antenna, computer related parts; VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave parts, audio parts, audio Audio equipment parts such as laser disk, compact disk, lighting parts, refrigerator parts, air conditioner parts, typewriter parts,
Household and office electrical product parts such as word processor parts; office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning equipment, motor parts, lighters, machine related parts such as typewriters Parts: Optical equipment such as microscopes, binoculars, cameras, watches, precision machinery related parts: Alternator connector, IC regulator,
Potentiometer base for light deer, various valves such as exhaust gas valve, fuel related / exhaust system / intake system various pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine cooling water joint, captor main body, captor spencer, Exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, slot position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, air conditioner thermostat base, heating warm air flow control valve, radiator motor Brush holder, water pump impeller, turbine vane, wiper motor related parts, dust tributer, starter switch , Starter relay, wire harness for transmission, window washer nozzle, air conditioner panel switch board, coil for fuel related electromagnetic valve, fuse connector, horn terminal, electrical component insulating plate, step motor rotor, solenoid bobbin, engine oil filter, ignition device It is useful for automobiles, vehicle-related parts such as cases, and other various applications.

Claims (1)

[Claims] 1. (A) The following structural units [(I), (II) and (IV)] or [(I), (II), (III) and (IV)]
] Based on 100 parts by weight of the liquid crystal polyester forming the anisotropic molten phase, (B) fixed carbon is 95% or more, the average particle size is 1 to 10 μm, and the specific surface area is 5
A liquid crystalline polyester resin composition obtained by kneading 1 to 100 parts by weight of scaly graphite and / or scaly graphite having a lamellar spacing of crystals of 350 angstroms or more and ˜15 m ² / g. (However, R1 in the formula is R2 represents one or more groups selected from Represents one or more groups selected from Further, in the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (II
I)] and structural unit (IV) are substantially equimolar. )