JP2001026699A - Liquid crystal polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide liquid crystal polyester resin compositions which excel in dispersion of a fluororesin component and have good external appearance, mechanical strengths, and sliding properties of the resulting resin molded articles and are particularly useful as the starting materials for resin molded articles in electric/electronic fields and the like. SOLUTION: Liquid crystal resin compositions comprise 100 pts.wt. liquid crystal polyester resin and 0.2-50 pts.wt. low molecular weight fluorocarbon polymer having an incipient fluidization temperature, obtained by the method shown below, of not higher than 350 deg.C. The incipient fluidization temperature is a temperature showing a melt viscosity of 40,000 P measured by heating the polymer at a rate of raising temperature of 4 deg.C/min and extruding the melt under a load of 100 kg/cm2 through a nozzle with an inner diameter of 1 mm and a length of 10 mm of a capillary rheometer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal polyester resin composition having good appearance, mechanical strength and slidability, which can be used as a raw material of a resin molded product in the electric and electronic fields and the like. The present invention relates to a liquid crystal polyester resin composition having an improved dispersibility of a fluororesin.

[0002]

2. Description of the Related Art A molten liquid crystalline polyester resin (hereinafter sometimes referred to as LCP) which exhibits liquid crystallinity when melted has excellent heat resistance and excellent fluidity and workability at the time of melting, so that precision molding is possible. As a resin molding material, it is being used in various fields such as electric and electronic fields.
In addition, polytetrafluoroethylene (hereinafter, PT
It is known that a resin composition containing a fluororesin such as FE) has improved self-lubricating properties, and improved releasability from a mold and friction and wear characteristics during molding. I have. Techniques relating to a resin composition comprising a liquid crystal polyester resin and PTFE are disclosed in, for example, US Pat. Nos. 4,417,020 and 4,429,078.

[0003]

However, generally, fluororesins, especially PTFE having a high self-lubricating effect, have a high melting point, and have a very high melt viscosity or hardly flow even at a temperature higher than the melting point. Therefore, in a resin composition in which such a fluororesin is blended with a liquid crystal polyester resin, it is difficult to satisfactorily disperse the fluororesin even by shearing in processing such as kneading and extrusion, or injection molding, and it also causes aggregation. Extremely poor dispersibility. As a result, the appearance of the molded article is reduced, the mechanical strength is reduced, the mold release from the mold is insufficient, or the fluororesin particles fall off the surface of the molded article. An object of the present invention is to provide a liquid crystal polyester resin composition having excellent dispersibility, particularly excellent dispersibility of a fluororesin component. Another object of the present invention is to provide a liquid crystal polyester resin composition having good appearance, mechanical strength and slidability of the obtained resin molded product, and particularly useful as a raw material of the resin molded product in the electric and electronic fields. To provide.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned object can be achieved by adding a specific fluorocarbon polymer to a liquid crystal polyester resin. And led to the present invention. That is, according to the present invention, based on 100 parts by weight of the liquid crystal polyester resin, a liquid crystal polyester resin composition containing 0.2 to 50 parts by weight of a low-molecular-weight fluorocarbon polymer having a flow start temperature of 350 ° C. or lower determined by the following method. Is provided. Flow start temperature: inner diameter 1 mm, length 1
Using a capillary rheometer with a 0 mm nozzle,
A temperature at which a melt viscosity measured by extruding a heated melt from a nozzle at a heating rate of 4 ° C./min under a load of 100 kg / cm ² shows 48,000 poise.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention contains a liquid crystal polyester resin and a specific low molecular weight fluorocarbon polymer in a specific ratio. Examples of the liquid crystal polyester resin used in the present invention include polyesters generally called a thermotropic liquid crystal polymer. For example, the following (1) to (4)
And the like. (1) Polyester comprising a combination unit of aromatic dicarboxylic acid, aromatic diol and aromatic hydroxycarboxylic acid, (2) Polyester comprising different aromatic hydroxycarboxylic acid units, (3) Aromatic dicarboxylic acid and aromatic Polyester comprising a combination unit with a diol, (4)
A polyester obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate.
These liquid crystal polyester resins may be used in combination of two or more. Further, instead of the aromatic dicarboxylic acid, aromatic diol and aromatic hydroxycarboxylic acid, ester-forming derivatives thereof may be used.
Liquid crystal polyester resin is 400 ℃
Preference is given to using polyesters which form anisotropic melts at the following temperatures:

Examples of the repeating structural unit of the liquid crystal polyester include, but are not limited to, the following structural units. Repeating structural unit derived from aromatic hydroxycarboxylic acid:

[0007]

Embedded image Repeating structural unit derived from aromatic dicarboxylic acid:

[0008]

Embedded image Repeating structural unit derived from aromatic diol:

[0009]

Embedded image

[0010]

Embedded image

The liquid crystal polyester resin used in the present invention is preferably a liquid crystal polyester resin containing at least 30 mol% of the repeating structural unit represented by the formula (A ₁ ) in view of the balance between heat resistance, mechanical properties and workability. Use is particularly preferred. As a combination of the above repeating structural units,
The following combinations (a) to (g) are preferred. (a): Combination of (A ₁ ), (B ₁ ) and (C ₁ ), (b): (A ₁ ), (B ₁ ), (B ₂ ) and (C ₁ ) (C): a combination of (A ₁ ) and (A ₂ ); (d): a combination of the structural units of (a) or (b)
Combinations replaced a part of (A ₁₎ with (A _2), in combination with structural units of (e) :( a) or (b),
A combination of (B ₁ ) in which a part of (B ₃ ) is replaced, (f): in the combination of the structural units of (a) or (b),
Combinations replaced partially with (C ₃₎ of (C _1), the combination of the structural units of (g) :( c), ( B 1) and (C ₂₎
Combination with the addition of structural units. The liquid crystal polyester resins (a), (b) and (c) having the basic structure are described in, for example,
No. 47870, JP-B-63-3888, and the like.

The specific fluorocarbon polymer used in the present invention is not particularly limited as long as it has a flow starting temperature of 350 ° C. or lower according to the above-mentioned method. The flow start temperature is preferably 225 ° C. to 350 ° C., more preferably 26 ° C.
5 ° C to 350 ° C. The fluorocarbon polymer,
It has a low molecular weight as indicated by the flow start temperature, has good fluidity during melt kneading, and has excellent dispersibility in a liquid crystal polyester resin. For example, PTFE, tetrafluoroethylene-hexafluoropropylene copolymer, polytrichlorofluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and the like can be mentioned, and low molecular weight PTFE in which the terminal is fluorinated is particularly preferable. Commercial products of such PTFE include "Sefralube I" and "Sefralube IP" manufactured by Central Glass Co., Ltd.
In the present invention, the content of the fluorocarbon polymer is based on 100 parts by weight of the liquid crystal polyester resin.
0.2 to 50 parts by weight. If the amount is less than 0.2 parts by weight, it is difficult to obtain the effect of adding the fluorocarbon polymer.
On the other hand, if the amount is more than 50 parts by weight, the resulting molded article will have reduced mechanical strength and moldability.

The resin composition of the present invention may contain a filler in order to improve the properties such as the elastic modulus and mechanical strength of the obtained molded article. As the filler, glass fiber or carbon fiber is particularly useful, and both can be used in combination. The length of the fiber as such a filler is not particularly limited, and can be appropriately selected according to a desired molded product. The mixing ratio when compounding a filler such as glass fiber or carbon fiber is in the range of 10 to 100 parts by weight with respect to 100 parts by weight of the liquid crystal polyester resin. It is preferable from the point.
In addition to the above glass fibers and carbon fibers, if necessary, for example, fibrous fillers such as ceramic fibers, silica alumina fibers, wollastonite, potassium titanate fibers, and aramid fibers; calcium carbonate, talc, mica, clay ,
One or more kinds of inorganic fillers such as glass beads may be blended.

The resin composition of the present invention contains a coloring agent such as a dye and a pigment, as long as the object of the invention is not impaired; an antioxidant;
One or more conventional additives such as a heat stabilizer, an ultraviolet absorber, an antistatic agent, and a surfactant can be added. Also,
In the present invention, in addition to the liquid crystal polyester resin, a small amount of other thermoplastic resin or thermosetting resin can be blended. Examples of the thermoplastic resin include polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide and the like. Examples of the thermosetting resin include a phenol resin, an epoxy resin, and a polyimide resin. These may be used in combination of two or more.

The means for compounding the resin composition of the present invention is not particularly limited. For example, a liquid crystal polyester resin and the above fluorocarbon polymer, and, if necessary, a filler such as glass fiber, and further various additives, a Henschel mixer,
A method of mixing by a tumbler or the like and melt-kneading using an extruder is generally used.

A part molded from the resin composition of the present invention;
The use of the member is not particularly limited. For example, electrical and electronic components such as connectors, sockets, relay components, coil bobbins, optical pickups, oscillators, printed wiring boards, computer-related components; semiconductor manufacturing process-related components such as IC trays and wafer carriers; VTRs, televisions, irons, Home appliance parts such as air conditioners, stereos, vacuum cleaners, refrigerators, rice cookers, and lighting fixtures; lighting fixture parts such as lamp reflectors and lamp holders; acoustic product parts such as compact discs, laser discs (registered trademark), and speakers; optical cables Ferrules, telephone parts,
Communication equipment parts such as facsimile parts and modems;
Copier-related parts such as heater holders; mechanical parts such as impellers, fan gears, gears, bearings, motor parts and cases; automotive parts such as automobile mechanical parts, engine parts, engine room parts, electrical parts, and interior parts; Cooking utensils such as microwave cooking pots and heat-resistant dishes; heat insulation and soundproofing materials such as flooring and wall materials; supporting materials such as beams and columns; building materials such as roofing materials; and civil engineering building materials; aircraft , Spacecraft,
Space equipment parts; radiation facility members such as nuclear reactors, marine facility members, cleaning jigs, optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts and medical materials, sensors It can be used for a wide range of applications such as similar parts and sanitary equipment.

The resin composition of the present invention can be used as an industrially useful material by forming it into a film or sheet. For example, it can be used for parts for display devices, films for electrical insulation, films for flexible circuit boards, films for packaging, films for recording media, and the like.

Further, the resin composition of the present invention comprises a continuous fiber,
It can be used as an industrially useful material by processing it into a fibrous form such as short fiber or pulp. Examples include clothing, heat-insulating materials, reinforcing materials for FRP, rubber reinforcing materials, ropes, cables, nonwoven fabrics, and the like.

[0019]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. In addition, the performance evaluation of the molded article in the examples was based on the following method. (i) Dispersibility of PTFE: The injection molded product was polished, observed with a scanning electron microscope at a magnification of 500 to 1000 times, and the dispersibility and dispersed particle diameter were evaluated. (ii) Tensile strength: ASTM No. 4 dumbbell was molded using an injection molding machine, and measured in accordance with ASTM D638. (iii) Deflection temperature under load: 12.7 m using an injection molding machine
m × 6.4 mm × 127 mm test piece
It was measured according to MD648. (iv) Izod impact strength (without notch): 127 m long
ASTM D2 was obtained by dividing a bending test piece having a width of 12.7 mm, a width of 12.7 mm and a thickness of 6.4 mm into two in the injection direction.
It measured according to 56. (v) Release resistance: Using an injection molding machine (Cycap N110 / 45 manufactured by Sumitomo Heavy Industries, Ltd.), inner diameter 11 mm, outer diameter 15
A cylindrical bush having a height of 15 mm and a height of 15 mm was molded at a cylinder temperature of 350 ° C. and a mold temperature of 130 ° C., and the release resistance when releasing from the mold was detected by installing a pressure sensor on an ejector pin. At this time, the mold release resistance of the composition of the present invention was expressed in% with respect to a composition not containing PTFE as a reference (100%), and was regarded as the mold release resistance. (vi) Coefficient of friction: A wear ring having an outer shape of 25.6 mm, an inner diameter of 20 mm, and a height of 15 mm is injection-molded, and the mating material is set to SUS304 using a Suzuki-type friction and wear tester, pressure P = 6 kg.
/ cm ² , velocity V = 40 m / min. (vii) Molded product appearance: The surface of the injection molded product was visually observed.

Examples 1 and 2, Comparative Examples 1, 2 and 3 The repeating structural units consist of A ₁ , B ₁ , B ₂ and C ₁ , and the molar ratio of A ₁ : B ₁ : B ₂ : C ₁ Is 60: 15: 5: 2
The liquid crystal polyester resin having a flow starting temperature of 330 ° C. and a melting point of 318 measured by the above method as PTFE.
C. and fluorinated to the end (Central Glass Co., Ltd., trade name "Sefrallube I") or the measurement by the above-mentioned flow starting temperature measurement method, 380
Fluorine resin with a melting point of 326 ° C
(Trade name: "Fluon L169J", manufactured by K.K.) and short glass fibers (EFH75-01, manufactured by Central Glass Co., Ltd.) were mixed with a composition shown in Table 1 using a Henschel mixer. Next, granulation was performed at a cylinder temperature of 340 ° C. using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) to obtain pellets of a liquid crystal polyester resin composition. The obtained pellets were subjected to a cylinder temperature of 350 ° C. and a mold temperature of 130 using a PS40E5ASE type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd.
A test piece for the above evaluation was formed by injection molding at ℃. Table 1 shows the evaluation results. It has been found that the liquid crystal polyester resin composition of the present invention gives a good dispersion of PTFE and provides a molded article having excellent self-lubricating properties.

[0021]

[Table 1]

Example 3 The repeating structural unit comprises A ₁ , B ₁ , B ₂ and C ₁ , and the molar ratio of A ₁ : B ₁ : B ₂ : C ₁ is 60: 15: 5: 2.
The liquid crystal polyester and PTFE having a flow start temperature of 344 ° C. and a melting point of 323 ° C. measured by the above method were used as PTFE
Fluorine resin fluorinated to the end and (Central Glass Co., Ltd., trade name "Sefrallube IP"), short glass fiber (Central Glass Co., Ltd. EFDE90-01),
And talc (S talc manufactured by Hayashi Kasei Co., Ltd.) were mixed with the composition shown in Table 2 using a Henschel mixer. Next, granulation was performed at a cylinder temperature of 340 ° C. using a twin-screw extruder (PCM-30, Ikegai Iron Works Co., Ltd.) to obtain pellets of a liquid crystal polyester resin composition. The obtained pellets were injection-molded at a cylinder temperature of 350 ° C. and a mold temperature of 130 ° C. using a PS40E5ASE type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd. to form test pieces for the above evaluation. Table 2 shows the evaluation results.

Comparative Example 4 As a PTFE, a fluororesin which does not flow even at 380 ° C. and has a melting point of 326 ° C. (manufactured by Asahi Glass Co., Ltd., trade name “Fluon L169
J)), except that the resin composition was granulated and a test piece was molded in the same manner as in Example 3, and each test was conducted. Table 2 shows the evaluation results. From the results in Table 2, it was found that the resin composition according to the present invention was excellent in the dispersibility of PTFE and exhibited good performance.

[0024]

[Table 2]

[0025]

Since the liquid crystal polyester resin composition of the present invention contains a specific fluorocarbon polymer in a specific ratio in the liquid crystal polyester resin, the dispersibility of the fluorocarbon polymer is excellent, and the appearance of the obtained resin molded product is improved. The mechanical strength and the slidability can be improved. Therefore,
In particular, it is useful as a raw material for resin molded articles in the electric and electronic fields, and for a wide range of uses.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 67/03 C08L 67/03 F term (Reference) 4J002 BD122 BD152 BD162 CF001 CF061 CF161 CF181 DA016 DL006 FA046 FD016 GB01 GD00 GG02 GL00 GM00 GM05 GN00 GP00 GQ00 GS00

Claims (5)

[Claims] 1. A liquid crystal polyester resin composition containing 0.2 to 50 parts by weight of a low molecular weight fluorocarbon polymer having a flow start temperature of 350 ° C. or less, determined by the following method, based on 100 parts by weight of a liquid crystal polyester resin. Flow start temperature: 100 kg / cm ² using a capillary rheometer having a nozzle having an inner diameter of 1 mm and a length of 10 mm.
The melt viscosity measured by extruding the heated melt from the nozzle at a heating rate of 4 ° C./min under a load of
Temperature indicating 00 poise. 2. The liquid crystal polyester resin composition according to claim 1, wherein the low molecular weight fluorocarbon polymer is polytetrafluoroethylene fluorinated to the terminal. 3. The liquid crystal polyester resin contains a repeating structural unit represented by the formula (A ₁ ) in an amount of at least 30 mol% of the whole.
The liquid crystal polyester resin composition according to claim 1, further comprising: Embedded image 4. The liquid crystal polyester resin composition according to claim 1, further comprising a glass fiber and / or a carbon fiber as a filler. 5. The content ratio of glass fiber and / or carbon fiber is 1 to 100 parts by weight of liquid crystal polyester resin.
The liquid crystal polyester resin composition according to claim 4, wherein the amount is from 0 to 100 parts by weight.