JPH1025402A - Liquid-crystal polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid-crystal polyester resin composition giving a molding which has excellent sliding properties and is satisfactory in mechanical properties and thermal stability. SOLUTION: The composition comprises: 100 pts.wt. liquid-crystal polyester; 5-180 pts.wt. at least one compound selected among the oxides, peroxides, composite oxides, and carbonates of metals belonging to Groups 1A and 2A of the Periodic Table, e.g. talc, wollastonite, dolomite, magnesium oxide, and potassium titanate; and 0.1-80 pts.wt. fluororesin.

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 excellent sliding properties and providing a molded article having good mechanical properties and thermal stability.

[0002]

2. Description of the Related Art Along with the recent progress in lightening, thinning, and miniaturization, demands for weight reduction and cost reduction are increasing in various mechanical parts applications, and synthetic resins are increasingly used.
In such mechanical component applications, good sliding characteristics are often required. Conventionally, resins such as polyacetal, polyamide, and polytetrafluoroethylene, or solid lubricants, lubricating oils, etc., have been slid on them. Compositions added as a property improving material have been used. They exhibit good sliding characteristics in normal machine operating temperature atmospheres, for example, in the temperature range of -40 ° C to 70 ° C, but under high temperature and high humidity conditions, increase wear, dimensional change, deformation, etc. You will not be able to use it. In the case of OA equipment and electronic components, polyamide, polyamide,
General-purpose engineering plastics, such as polyacetal, lacked heat resistance and were unusable due to melting, let alone deformation. In addition, such general-purpose engineering plastics cannot satisfy the dimensional accuracy required for small precision mechanical parts and the like because of their large molding shrinkage and linear expansion coefficient.

For the purpose of solving the problems of heat resistance and dimensional stability and imparting sliding characteristics, it has been proposed to add fillers such as glass fibers, carbon fibers, and various whiskers to liquid crystal polyester. But the mating material of the sliding part is
Conventional steel, hard metals such as stainless steel and ceramics, etc., soft metals such as aluminum and copper, or so-called super engineering plastics with excellent heat resistance and dimensional stability are increasingly used, In this case, there is also a problem that the mating material is easily damaged depending on the filler used. For example, Japanese Patent Laid-Open No. 4-4296 proposes using glassy carbon as a filler for liquid crystal polyester. In this case, the mating material is good for hard metals such as stainless steel. Although it exhibits sliding characteristics, it is not preferable for a soft metal such as aluminum because the mating material is worn. JP-A-59-147034 proposes to use wollastonite having a specific shape as a filler in a liquid crystal polyester. However, in the above-mentioned publication, although its own wear is suppressed, its effect is insufficient to reduce the friction coefficient. JP-A-5-320675 and JP-A-5-320676 propose to use an inorganic powder having a Mohs hardness of 2 to 4 as a filler in a liquid crystal polyester. The effect of reducing the coefficient was insufficient. JP 5-10
No. 5804 proposes to use a specific fluororesin as a filler for liquid crystal polyester. In this case, the friction coefficient was rather increased under sliding conditions, especially under light sliding conditions, such as small precision mechanical parts, and it could not be used.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and provides a liquid crystal polyester resin composition which provides a molded article having excellent sliding characteristics and good mechanical properties and thermal stability. The purpose is to provide things.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that liquid crystal polyesters contain oxides, peroxides, and the like of metals belonging to Group 1A or 2A of the periodic table. At least one compound selected from a complex oxide and a carbonate, and a fluororesin are respectively blended in a specific amount to obtain a liquid crystal polyester resin composition that achieves the above object, and using the composition. The present inventors have found that a component having excellent sliding characteristics can be produced by the method of the present invention. That is, the present invention is as described below. (1) At least one selected from the group consisting of oxides, peroxides, double oxides, and carbonates of metals belonging to Group 1A or 2A of the periodic table with respect to 100 parts by weight of the liquid crystal polyester.
5 to 180 parts by weight of at least one kind of compound and 0.1% of fluororesin
A liquid crystal polyester resin composition comprising -80 parts by weight. (2) at least one compound selected from the group consisting of oxides, peroxides, double oxides, and carbonates of metals belonging to Group 1A or 2A of the periodic table is composed of talc, wollastonite, dolomite, or oxidized metal; The liquid crystal polyester resin composition according to the above (1), which is at least one compound selected from magnesium and potassium titanate. (3) At least 90% by weight or more of at least one compound selected from the group consisting of oxides, peroxides, double oxides, and carbonates of metals belonging to Group 1A or 2A of the Periodic Table is 300 mesh. The liquid crystal polyester resin composition according to the above (1) or (2), having the following size. (4) The above-mentioned (1), (2) or (1), wherein the fluororesin is a low-molecular-weight fluorocarbon polymer having a flow temperature of 350 ° C. or lower determined by the following method, wherein the fluorocarbon resin is fluorinated to the molecular chain end. 3) Liquid crystal polyester resin composition described in [1] Flowing temperature: using a capillary rheometer having a nozzle having an inner diameter of 1 mm and a length of 10 mm, under heating at a rate of 4 ° C./min under a load of 100 kg / cm ² , using a hot melt nozzle. The temperature at which the melt viscosity shows 48,000 poise when extruded from (5) The liquid crystal polyester resin composition according to the above (1), wherein the liquid crystal polyester contains at least 30 mol% of a repeating structural unit represented by the following formula (A ₁ ). (6) A molded article comprising the liquid crystal polyester resin composition according to (1), (2), (3), (4) or (5).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal polyester used in the present invention is a polyester called a thermotropic liquid crystal polymer, which comprises (1) a combination of an aromatic dicarboxylic acid and an aromatic hydroxycarboxylic acid;
(2) An aromatic hydroxycarboxylic acid was reacted with (3) an aromatic dicarboxylic acid, a combination of an aromatic dicarboxylic acid and an aromatic diol, and (4) a polyester such as polyethylene terephthalate. And an anisotropic melt at a temperature of 400 ° C. or lower. In addition, in place of these aromatic dicarboxylic acids, aromatic diols, and aromatic hydroxycarboxylic acids, ester-forming derivatives thereof may be used. Examples of the repeating structural unit of the liquid crystal polyester include, but are not limited to, the following. 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

Balance between heat resistance, mechanical properties and workability
Particularly preferred liquid crystal polyesters are those of the formula A₁Represented by
Containing at least 30 mol% of repeating structural units
It is. Specifically, the combination of repeating structural units is
The following (a) to (f) are preferred. (A): (A₁), (B₁) Or (B)₁) And (B_Two) Mixture
Compound, (C₁). (B): (A₁), (A_Two). (C): Smell of the combination of the structural units of (a)
A₁A part of_TwoReplaced by (D): Smell of the combination of the structural units of (a)
And B₁Part of B_ThreeReplaced by (E): Smell of the combination of the structural units of (a)
And C₁Part of C_ThreeReplaced by (F): B is added to the combination of the structural units of (b).₁When
C₁With the addition of structural units. Of these, in the combination of (a), A
₁/ C₁Is 0.2 to 1.0, (B₁+ B_Two)
/ C₁Is 0.9 to 1.1, B₁/ B _TwoMole of
More preferred is a molar ratio of 0 to 1.0.
And the flow temperature defined by the method described above is 28
0 to 400 ° C, preferably 300 to 360 ° C, further
Preferably, a temperature of 315 to 330 ° C is used.
it can. Liquid crystal poly of (a) and (b), which are basic structures
As for the ester, for example, JP-B-47-4
No. 7870, JP-B-63-3888, etc.
Have been.

The oxides and peroxides of metals belonging to Group 1A or 2A of the periodic table used in the present invention are represented by the general formula M
₂ O, M'O or M'O ₂ (wherein M is 1A
Group M ′ is a metal element belonging to Group 2A. ). In particular, M is preferably selected from Na and K, and M 'is preferably selected from Mg, Ca, and Ba. Examples include calcium oxide (99.9%), magnesium oxide (heavy, special grade reagent), barium oxide (for chemicals), barium peroxide (wako first grade), Kyowa Chemical Industry, available from Wako Pure Chemical Industries, Ltd. Examples include, but are not limited to, Pyrokissma 3320 and Micromag 3-30 available under the trade name available from Co., Ltd.

The double oxide containing a metal belonging to Group 1A or 2A of the periodic table used in the present invention is represented by the general formula M ₂
O · mM ”O ₂ · xH ₂ O, pM′O · mMm” O ₂ · x
_{H 2 O, M 2 O ·} pM '''2 O 3 · mM "O 2 · xH 2 O
Or M ₂ O.pM'Om m '" ₂ O ₃ .nM" O ₂ .x
H ₂ O (wherein M is a metal element belonging to Group 1A,
M ′ is a metal element belonging to group 2A, M ″ is a tetravalent metal element, M ″ ′ is a trivalent metal element, p, m, and n are positive numbers of 1 or more, and x is a positive number of 0 or more. In particular,
M is preferably K, and M ′ is Mg, Ca, Ba
It is preferably selected from the following. Examples include, but are not limited to, talc, wollastonite, attapulgite, sericite, mica, potassium titanate, barium titanate, and the like.

The carbonate containing a metal belonging to Group 1A or 2A of the periodic table used in the present invention is represented by the general formula M ₂
CO ₃ , M′CO ₃ or M ′ · M ″ (CO ₃ ) ₂ (wherein M is a metal element belonging to Group 1A and M ′ and M ″ are metal elements belonging to Group 2A). In particular, M is preferably K, and M ′ and M ″ are preferably selected from Mg, Ca, and Ba. Examples thereof include potassium carbonate, calcium carbonate, and dolomite. The talc, wollastonite, dolomite, magnesium oxide, and potassium titanate are preferable, and wollastonite and talc are particularly preferable. Or one or more of them may be used at the same time.
The particle size of at least one compound selected from the group consisting of oxides, peroxides, double oxides, and carbonates of metals belonging to Group A or 2A is preferably 300 mesh or less. If it is larger than 300 mesh pass, the effect of imparting sliding properties to the liquid crystal polyester is 3
Although it is not so different from those having a mesh pass of not more than 00, it is not preferable in terms of appearance of the molded article, uniform dispersibility in the molded article, and the like.

The fluororesin used in the present invention is a polymer comprising an olefin containing a fluorine atom in the molecule. Examples of the basic polymer include polytetrafluoroethylene (hereinafter abbreviated as PTFE) and tetrafluoroethylene. -Hexafluoropropylene copolymer, polytrichlorofluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, etc.
TFE is preferred. Fluororesin used in the present invention,
Preferably, it is a low molecular weight fluorocarbon polymer that is fluorinated to the end of the molecular chain and has a flow temperature of 350 ° C. or less as defined by the above method. The fluorocarbon polymer is disclosed in JP-A-61-118331 and JP-A-61-183331.
As described in JP-A-162503, 25 fluorine-containing polymers containing non-fluorinated hydrogen atoms are used.
It is produced by contact reaction with a nitrogen-containing fluorine compound at 0 to 550 ° C., or at least one of molecular fluorine, halogenated fluoride and rare gas fluoride.
Manufactured by contact reaction with a species. Examples of this include Sefrallube I, IP, and the like, available from Central Glass Co., Ltd.

In the liquid crystal polyester resin composition of the present invention, at least one compound selected from the group consisting of oxides, peroxides, double oxides and carbonates of metals belonging to Group 1A or 2A of the periodic table. The compounding ratio is 5 to 180 parts by weight, preferably 10 to 150 parts by weight, and more preferably 20 to 120 parts by weight based on 100 parts by weight of the liquid crystal polyester. The compounding ratio of at least one compound selected from the group consisting of oxides, peroxides, double oxides, and carbonates of metals belonging to Group 1A or 2A is 180.
When the amount is more than the weight part, the fluidity during the molding process is deteriorated, and it is difficult to obtain a good molded product, and the abrasion of the cylinder and the mold of the molding machine is undesirably increased. An oxide of a metal belonging to Group 1A or 2A;
If the compounding ratio of at least one compound selected from peroxides, double oxides, and carbonates is less than 5 parts by weight, the desired effect of improving the sliding properties is not sufficient, which is not preferable. In the liquid crystal polyester resin composition of the present invention, the mixing ratio of the fluororesin is 1
0.1 to 80 parts by weight, preferably 0.5 to 50 parts by weight, more preferably 1 to 100 parts by weight, per 100 parts by weight.
30 parts by weight. When the mixing ratio of the fluororesin is more than 80 parts by weight, it is not preferable because the mechanical strength and the heat resistance decrease. Also, when the compounding ratio of the fluororesin is less than 0.1 part by weight, the desired effect of improving the sliding properties is insufficient, which is not preferable. In addition, the liquid crystal polyester resin composition used in the present invention, a reinforcing material such as glass fiber, glass beads, and carbon fiber; a coloring agent such as a dye and a pigment; an antioxidant; One or more conventional additives such as a heat stabilizer, an ultraviolet absorber, an antistatic agent, and a surfactant can be added. Further, it is also possible to add one or more substances having an external lubricant effect such as higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, and fluorocarbon surfactants.

Also, a small amount of a thermoplastic resin such as polyamide, polyester, polyphenylene sulfide,
Polyetherketone, polycarbonate, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide and the like, and a small amount of thermosetting resin, for example, phenol resin, epoxy resin,
One or more kinds such as a polyimide resin may be added. The means for compounding the raw material components for obtaining the liquid crystal polyester resin composition of the present invention is not particularly limited, and each component is separately supplied to a melt mixer, or these raw materials are mortar, Henschel mixer, ball mill, It can be preliminarily mixed using a ribbon blender or the like and then supplied to a melt mixer. The liquid crystal polyester resin composition of the present invention can be used for various mechanical parts having movable parts, for example, electric / electronic parts (switches, relays, connectors, sockets, etc.), OA / AV equipment (printers, copiers, facsimiles, video decks). , Video camera, floppy disk drive, hard disk drive, C
It is suitably used for D-ROM drives, magneto-optical disk drives, etc., and other mechanical parts (steel cameras, cooking devices using electromagnetic waves, automobile parts).

[0018]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The physical properties in the examples were measured by the following methods. (1) Friction coefficient Using a Suzuki-type friction and wear tester (TRI-S100D: manufactured by Takachiho Seiki Co., Ltd.), a ring test piece having an inner diameter of 17 mm, an outer diameter of 21 mm, and a height of 10 mm was applied at a pressure of 2 kg / cm ² and a speed of 5
The measurement was performed using the same material as the mating material under the condition of m / min. (2) Tensile strength Using an ASTM No. 4 tensile dumbbell, ASTM D63
8 was measured. (3) Creep test Creep tester (PSS-6: manufactured by Shimadzu Corporation)
A bar-shaped test piece having a width of 12.6 mm, a thickness of 6.4 mm and a length of 126 mm was attached to a three-point bending test jig using
At 0 ° C. under a load of 150 kg / cm ² , the time change of the deformation amount was measured.

Examples 1 to 3 and Comparative Examples 1 to 3₁, B₁, B_Two, C₁From
A₁: B₁: B _Two: C₁Is a molar ratio of 60:15:
5:20, the flow onset temperature defined by the method described above
Is 323 ° C and 1A of the periodic table
Or oxides, peroxides, double oxidations of metals belonging to Group 2A
, And at least one or more selected from carbonates
Wolasse as a compound of 300 mesh pass or less
Tonight (NYCO # 400, trade name NYAD # 400),
And PTFE (Central Glass)
A set shown in Table 1 with the product name Sefrallube I)
After mixing with a Henschel mixer, the twin-screw extruder (Pond
Using a PCM-30 (made by Kaikai Tekko Co., Ltd.), the cylinder
Granulate at a temperature of 340 ° C. to obtain a liquid crystal polyester resin composition.
Obtained. These liquid crystal polyester resin compositions were heated at 120 ° C.
After drying for 3 hours with an injection molding machine (Nissei Plastic Industry Co., Ltd.
S40E5ASE type) and cylinder temperature of 350
At ℃ and mold temperature of 130 ° C, ASTM No.4
Forming tension dumbbells and rod-shaped test specimens for creep tests
did. Using these test pieces, the coefficient of friction, tensile strength,
And creep test measurements. Table 1 and Table
It is shown in FIG. Similarly, liquid crystal poly that does not contain fluororesin
Ester resin composition (Comparative Example 1), wollastonite
The filling amount is 0.05 parts by weight, and the fluororesin is 5 parts by weight.
Liquid crystal polyester resin composition (Comparative Example 2)
133 parts by weight lastonite, fluororesin
Liquid crystal polyester resin composition having a filling amount of 100 parts by weight
For Comparative Example 3, the friction coefficient and the tensile strength were measured.
Was. Table 1 shows the results. Wollastonite and fluoroplastic
(Examples 1 to 3) containing a fluororesin
Coefficient of friction is lower than that of the composition (Comparative Example 1)
In addition to its small change over time, it has excellent mechanical properties.
I understand. Further, the filling amount of wollastonite is 0.0
5 parts by weight of liquid crystal polyester containing 5 parts by weight of fluororesin
The resin composition (Comparative Example 2) is not effective in reducing the coefficient of friction.
Was enough. On the other hand, the filling amount of wollastonite is 13
3 parts by weight, liquid with 100 parts by weight of fluororesin
Crystalline polyester resin composition (Comparative Example 3)
Large change with time and significant decrease in tensile properties
Was. Further, the compositions of Examples 1 and 3 were prepared in a high temperature atmosphere.
Specimen shows little heat deformation under the specimen and excellent heat resistance
ing.

Examples 4-7, Comparative Examples 4-7 Instead of wollastonite, talc (Nippon Talc Co., Ltd.) was used.
(Trade name: X-50), dolomite (trade name: Microdol I, manufactured by Hoechst Synthetic Co., Ltd.), potassium titanate (trade name: HT300, manufactured by Titanium Industry Co., Ltd.), magnesium oxide (trade name, manufactured by Kyowa Chemical Co., Ltd.) , Trade name Pyro Kisuma 3
An experiment was performed in the same manner as in Example 1 except that 320) was used. Table 1 shows the results. It can be seen that the liquid crystal polyester resin composition containing talc, dolomite, potassium titanate, magnesium oxide and a fluororesin has a low coefficient of friction, a small change with time, and excellent mechanical properties. Further, the liquid crystal polyester resin compositions containing no fluororesin (Comparative Examples 4 to 7) had a large coefficient of friction and a large change with time.

Example 8 A liquid crystal polyester resin composition containing 47 parts by weight of wollastonite, 3 parts by weight of fluororesin, and 17 parts by weight of glass fiber was measured for friction coefficient and tensile strength in the same manner as in Example 1. . Table 1 shows the results. Wollastonite and those obtained by adding glass fibers to a fluororesin also have a good coefficient of friction, have little change over time, and have excellent mechanical properties.

Comparative Example 8 Instead of the liquid crystal polyester resin composition, a polyphenylene sulfide resin composition containing 46 parts by weight of glass fiber and 8 parts by weight of a fluororesin was used as the polyphenylene sulfide resin, and the cylinder temperature was 280 ° C. and the mold temperature was 160 The time change of the test piece deformation was measured in the same manner as in Example 1 except that injection molding was performed at a temperature of ° C. In this case, the test piece was deformed beyond the measurement limit in a short time, and was not practically usable (Table 2).

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

The liquid crystal polyester resin composition of the present invention has excellent sliding properties (low friction coefficient) and can give a molded article having good mechanical properties and thermal stability. Slidable member can be obtained efficiently.

Claims (6)

[Claims] (1) 100 parts by weight of a liquid crystal polyester,
5 to 180 parts by weight of at least one compound selected from the group consisting of oxides, peroxides, double oxides and carbonates of metals belonging to Group 1A or 2A of the periodic table, and 0.1 to 80 of a fluororesin A liquid crystal polyester resin composition comprising parts by weight. 2. The method according to claim 1, wherein at least one compound selected from the group consisting of oxides, peroxides, double oxides and carbonates of metals belonging to Group 1A or 2A of the periodic table comprises talc, wollastonite, dolomite. 2. The liquid crystal polyester resin composition according to claim 1, which is at least one compound selected from the group consisting of magnesium oxide and potassium titanate. 3. At least one compound selected from the group consisting of oxides, peroxides, double oxides and carbonates of metals belonging to Group 1A or 2A of the periodic table.
3. The liquid crystal polyester resin composition according to claim 1, wherein 0% by weight or more has a size of 300 mesh pass or less. 4. A low molecular weight fluorocarbon polymer, wherein the fluororesin is fluorinated to the molecular chain end and the flow temperature determined by the following method is 350 ° C. or less. Liquid crystal polyester resin composition. Flow temperature: When using a capillary rheometer having a nozzle having an inner diameter of 1 mm and a length of 10 mm, when extruding a heated melt from a nozzle at a rate of 4 ° C./min under a load of 100 kg / cm ² , the melt viscosity is 48,000. Temperature indicating poise. 5. The liquid crystal polyester resin composition according to claim 1, wherein the liquid crystal polyester contains at least 30 mol% of a repeating structural unit represented by the following formula (A ₁ ). Embedded image 6. A molded article comprising the liquid crystal polyester resin composition according to claim 1, 2, 3, 4, or 5.