JP2003020385A - Resin composition for optical pickup parts - Google Patents

Abstract

(57) Abstract: A resin composition for an optical pickup component capable of producing a molded article having improved rigidity while maintaining high internal loss of LCP and excellent melt fluidity, and injection using the same. Provide molded products. The liquid crystal polyester resin precursor powder having a flow temperature of 200 ° C. to 240 ° C. is heat-treated. A resin composition for an optical pickup component, and an injection molded product obtained from the resin composition for an optical pickup component.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for optical pickup parts and an injection molded article using the same.

[0002]

2. Description of the Related Art In recent years, in order to reduce the weight of optical pickup parts mounted on an optical disk device, substitution of metal for resin has been promoted. Polyphenylene sulfide (PPS), liquid crystalline polyester (LCP) and the like are known as resins used for the parts. However, PPS
Is not suitable as an optical pickup component due to its small internal loss, while LCP has a high internal loss and excellent melt flowability, so it is easy to manufacture thin-walled molded products, Since the rigidity is low, there is a problem that sufficient vibration damping property cannot be obtained.

[0003]

The object of the present invention is to provide an LCP.
(EN) Provided are a resin composition for optical pickup parts capable of producing a molded article having improved rigidity while maintaining high internal loss and excellent melt fluidity, and an injection molded article using the same.

[0004]

Means for Solving the Problems As a result of intensive studies to find a resin composition for optical pickup parts which does not have the above-mentioned problems, the present inventors have found that the flow temperature is 200 ° C. to 240 ° C.
The resin composition for optical pickup parts, which comprises 50% by weight to 90% by weight of the liquid crystalline polyester resin and 10% by weight to 50% by weight of the inorganic filler, which has a high LCP The inventors have found that it is possible to produce a molded body having improved rigidity while maintaining internal loss and excellent melt fluidity, and completed the present invention.

That is, according to the present invention, the flow temperature is 200 ° C to 240 ° C.
A resin composition for optical pickup parts, which comprises 50 wt% to 90 wt% of a liquid crystalline polyester resin obtained by heat-treating a liquid crystalline polyester resin precursor powder Is provided.

The liquid crystalline polyester resin precursor powder used in the present invention includes, for example, (1) a combination of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol, and (2) different aromatic compounds. Examples thereof include those comprising a hydroxycarboxylic acid, (3) those comprising a combination of an aromatic dicarboxylic acid and an aromatic diol, (4) those obtained by reacting a polyester such as polyethylene terephthalate with an aromatic hydroxycarboxylic acid, and the like. It shows a flow temperature of 200 to 240 ° C. here,
The flow temperature is 4 ° C under a load of 100 kgf / cm ² using a capillary rheometer with a nozzle having an inner diameter of 1 mm and a length of 10 mm.
When extruding the heated melt from the nozzle at a heating rate of a minute,
It means the temperature at which the melt viscosity shows 48000 poise. In addition,
Instead of these aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids and aromatic diols, their ester-forming derivatives may be used.

As the ester-forming derivative of carboxylic acid, for example, one in which the carboxyl group is a derivative having a high reaction activity for acid chlorides, acid anhydrides, etc. and accelerating the reaction to form polyester, Examples thereof include those in which a carboxyl group forms an ester with an alcohol, ethylene glycol, or the like, and is a derivative that produces a polyester by a transesterification reaction. Examples of the ester-forming derivative of the phenolic hydroxyl group include those in which the phenolic hydroxyl group forms an ester with a carboxylic acid and forms a polyester by a transesterification reaction.

The aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid and aromatic diol are substituted with a halogen atom, an alkyl group such as a methyl group or an ethyl group, an aryl group or the like, as long as the ester-forming property is not impaired. May be.

Examples of the repeating structural unit which constitutes the liquid crystalline polyester resin precursor are shown below, but not limited thereto.

Repeating structural unit derived from aromatic hydroxycarboxylic acid: The above repeating structural unit may be substituted with a halogen atom or an alkyl group.

Repeating structural unit derived from aromatic dicarboxylic acid: The above repeating structural unit may be substituted with a halogen atom, an alkyl group or an aryl group.

Repeating structural unit derived from aromatic diol: The above repeating structural unit may be substituted with a halogen atom, an alkyl group or an aryl group.

In the repeating structural units derived from the above aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid and aromatic diol, the alkyl group has 1 to 1 carbon atoms.
An alkyl group having 10 carbon atoms is preferable, and an aryl group having 6 to 20 carbon atoms is preferable as the aryl group.

The liquid crystalline polyester resin precursor powder contains at least 30 mol% of repeating units represented by the above formula A _1.
It is preferable to include. Preferred combinations of repeating structural units include, for example, the following formulas (a) to (f). (A): (A ₁ ), (B ₁ ), (C ₃ ), or (A ₁ ),
A mixture of (B ₁ ) and (B ₂ ), (C ₃ ). (B) in those combinations of the structural units of :( a), obtained by replacing a part or all of (C ₃₎ to (C _1). (C) in those combinations of the structural units of :( a), obtained by replacing a part or all of (C ₃₎ to (C _2). (D) In those combinations of the structural units of :( a), obtained by replacing a part or all of (C ₃₎ to (C _4). (E) in what combination of structural units of :( a), replaced with the mixture of (C ₃₎ of some or all the _{(C 4) (C 5)} . (F) In those combinations of the structural units of :( a), obtained by replacing a part of (A ₁₎ to (A _2).

The liquid crystalline polyester resin precursor used in the present invention has a repeating structural unit of 30 to 80 mol derived from p-hydroxybenzoic acid (A ₁ ) from the viewpoint of exhibiting liquid crystallinity.
%, Hydroquinone (C ₁ ) and 4,4′-dihydroxybiphenyl (C ₃ ) at least one compound selected from the group consisting of 10 to 35 mol% of repeating structural units, terephthalic acid (B ₁ ), isophthalic acid It is preferably composed of 10 to 35 mol% of repeating structural units derived from at least one compound selected from the group consisting of (B ₂ ) and naphthalenedicarboxylic acid (B ₃ ). From the viewpoint of heat resistance and rigidity of the liquid crystalline polyester obtained by heat treatment, 40 to 70 mol% of repeating structural units derived from p-hydroxybenzoic acid (A ₁ ),
Repeating structural units 15～30Mol% derived from 4,4'-dihydroxybiphenyl (C _3), repeating structural units derived from a mixture of terephthalic acid (B ₁₎ or terephthalic acid (B ₁₎ and isophthalic acid (B ₂₎ More preferably, it comprises 15 to 30 mol%.

The method for producing the liquid crystalline polyester precursor powder used in the present invention is not particularly limited, but, for example, the phenolic hydroxyl group of an aromatic compound is acylated with a fatty acid anhydride, and the aromatic carboxylic acid is heated while heating It can be obtained by a method such as mechanically pulverizing a product obtained by transesterification with an acid. Examples of the fatty acid anhydride used here include lower fatty acid anhydrides such as acetic anhydride and propionic anhydride, and acetic anhydride is preferably used in terms of cost and handleability. The amount of the fatty acid anhydride used when acylating the phenolic hydroxyl group is preferably 1.05 to 1.1 times that of the phenolic hydroxyl group. Liquid crystal polyester precursor powder flow temperature 20
In order to adjust the temperature to 0 ° C. to 240 ° C., it is preferable to perform the acylation and transesterification reaction at 100 ° C. to 300 ° C. under normal pressure in an inert gas atmosphere. The particle size of the mechanically pulverized liquid crystalline polyester precursor powder is 3 mm because it can be uniformly heat-treated to obtain a uniform polymer with a small molecular weight distribution.
The following is preferable.

As a method of heat-treating the liquid crystalline polyester precursor powder to obtain the liquid crystalline polyester, for example, the liquid crystalline polyester precursor powder is heated in a high boiling point solvent such as a mixture of diphenyl and diphenyl ether or diphenyl sulfone at 240 ° C. to 370 ° C. After stirring at a temperature of ℃, a method of removing the high boiling point solvent to obtain a liquid crystalline polyester, or after changing the shape such as pelletizing the powder or the obtained powder by a granulator, 240 ℃ ~ 370 Examples include a method of treating at 0 ° C. under an inert gas atmosphere or under reduced pressure for 1 to 20 hours. When heat treatment is performed at a temperature lower than 240 ° C, the molecular weight tends to not reach sufficient mechanical strength,
Heat treatment at 370 ° C or higher tends to cause decomposition reaction. Examples of the heat treatment apparatus include known dryers, reactors, inert ovens, mixers, electric furnaces, and the like.

When the liquid crystalline polyester precursor powder is heat-treated, it is preferable to appropriately select the temperature rising rate of the heat treatment and the treatment temperature so that the liquid crystalline polyester particles are not fused. When fusion occurs, the reaction tends to be hindered. The atmosphere for heat treatment is preferably an inert gas atmosphere or a reduced pressure atmosphere, and examples of the inert gas include:
Examples thereof include nitrogen, helium, argon, carbon dioxide gas, and the like.

The flowing temperature of the liquid crystalline polyester obtained by heat-treating the liquid crystalline polyester precursor powder is not particularly limited, but the liquid crystalline polyester having a flowing temperature of 280 ° C. to 420 ° C. has excellent heat resistance and mechanical properties. A liquid crystalline polyester having a flow temperature of 310 ° C to 390 ° C is more preferable. If the flow temperature is lower than 280 ° C, problems such as blisters may occur in molding. Further, if the flow temperature exceeds 420 ° C, it tends to be difficult to mold without a decomposition reaction.

Examples of the inorganic filler used in the liquid crystalline polyester resin composition of the present invention include fibrous or plate-shaped inorganic fillers. Examples of the fibrous filler include glass fibers, carbon fibers, tyranno fibers, wollastonite, ceramic fibers such as potassium titanate fibers and aluminum borate, and organic fibers such as metal fibers and aromatic polyamide fibers. Especially, glass fibers are preferable from the viewpoint of economy and performance. Examples of the plate-shaped filler include talc, mica, graphite and the like, with talc being preferred.

The size of the fibrous inorganic filler is not particularly limited, but one having an average fiber diameter of 5 to 20 μm is preferable, and one having an average fiber diameter of 5 to 15 μm is more preferable. Average fiber diameter
When it is less than 5 μm, the fluidity and heat resistance tend to be insufficient, and when the average fiber diameter is more than 20 μm, the appearance of the molded product and the uniform dispersibility in the molded product tend to be poor. The average fiber length is preferably 10 to 300 μm, more preferably 50 to 300 μm. When the average fiber length is less than 10 μm, the fluidity and heat resistance tend to be insufficient, and when the average fiber length is more than 300 μm, the appearance of the molded product, the uniform dispersibility in the molded product, etc. are poor. Tend.

The size of the plate-like inorganic filler is not particularly limited, but one having an average particle size of 1 to 20 μm is preferable, and
It is more preferably about 20 μm. Average particle size is 1 μm
If it is less than the above range, fluidity and heat resistance may be insufficient, which is not preferable. If the average particle size is larger than 20 μm, it is not preferable in terms of appearance of the molded product and uniform dispersibility in the molded product.

In the liquid crystalline polyester resin composition of the present invention. The blending ratio of the fibrous and / or plate-like inorganic filler is 10 to 50% by weight based on the total amount of the resin composition,
It is preferably 20 to 40% by weight. If it is less than 10% by weight, the heat resistance is not sufficient, and if it exceeds 50% by weight, the thin-wall fluidity is deteriorated and the wear of the cylinder and die of the molding machine is increased.

In the liquid crystalline resin composition used in the present invention, a release-improving agent such as a fluororesin or a metallic soap; a coloring agent such as a dye or a pigment, to the extent that the object of the present invention is not impaired.
Antioxidant; heat stabilizer; UV absorber; antistatic agent;
Surfactants; higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, fluorocarbon-based surfactants and other external lubricants; polyamides, polyesters, polyphenylene sulfides, polyetherketones, polycarbonates, polyphenylene ethers and modified products thereof; Thermoplastic resin such as polysulfone, polyether sulfone, polyether imide; phenol resin, epoxy resin,
One or more thermosetting resins such as polyimide resin may be added.

The method of mixing the liquid crystalline polyester resin and the inorganic filler is not particularly limited. For example, the liquid crystalline polyester resin and the inorganic filler may be separately supplied to a melt mixer, or the liquid crystalline polyester resin and the inorganic filler may be supplied. The materials may be pre-mixed by using a mortar, a Hencil mixer, a ball mill, a ribbon blender, etc., and then supplied to the melt mixer.

The liquid crystal resin composition of the present invention is used for reading data, which is mounted on an optical disc device such as a digital video disc player, a CD-ROM player, a compact disc player for music, and a laser disc (registered trademark) player. It is a resin composition suitable for a lens holder of an optical pickup used, and by using the resin composition, an optical pickup component which is lightweight and excellent in rigidity can be manufactured.

[0027]

EXAMPLES The present invention will be described below with reference to examples, but it goes without saying that the present invention is not limited to the examples.

Synthesis Example 1 759.7 g (5.5 mol) of p-hydroxybenzoic acid was added to a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, and 4,4'-. Dihydroxybiphenyl 512.1 g (2.75 mol), terephthalic acid 434.0 g (2.61 mol), isophthalic acid 22.
8 g (0.138 mol) and 1235 g of acetic anhydride (1
2.1 mol) was charged. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes in a nitrogen gas stream, the temperature was maintained, and the mixture was refluxed for 3 hours. afterwards,
While distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised to 300 ° C over 2 hours and 30 minutes, and when the torque increase was recognized, the reaction was considered to be complete, and the contents were taken out in a molten state. It was The yield of the obtained liquid crystalline resin precursor is 1
It was 336 g. After crushing the liquid crystalline polyester resin precursor taken out into particles with an average particle size of 3 mm or less with a crusher, the flow temperature was measured to be 239 ° C, and at temperatures above 280 ° C, optical anisotropy was observed in the molten state. Was done.

Synthesis Example 2 759.7 g (5.5 mol) of p-hydroxybenzoic acid was added to a reactor equipped with a stirrer, a torque meter, a nitrogen gas introducing tube, a thermometer and a reflux condenser. Dihydroxybiphenyl 512.1 g (2.75 mol), terephthalic acid 434.0 g (2.61 mol), isophthalic acid 22.
8 g (0.138 mol) and 1235 g of acetic anhydride (1
2.1 mol) was charged. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes in a nitrogen gas stream, the temperature was maintained, and the mixture was refluxed for 3 hours. afterwards,
While distilling off the by-produced acetic acid and unreacted acetic anhydride which were distilled off, the temperature was raised to 330 ° C. over 3 hours, and when the increase in torque was observed, the reaction was considered to be completed, and the contents were taken out in a molten state. The yield of the obtained liquid crystalline resin precursor is 1357.
It was g. After crushing the liquid crystalline polyester resin precursor taken out into particles with an average particle size of 3 mm or less with a crusher, the flow temperature was measured to be 273 ° C, and at temperatures above 300 ° C, optical anisotropy was observed in the molten state. Was done.

Example 1 The liquid crystalline polyester precursor powder obtained in Synthesis Example 1 was heated from room temperature to 250 ° C. in 1 hour under a nitrogen atmosphere, and from 250 ° C. to 323 ° C. in 5 hours. 323
After heat-treating at ℃ for 3 hours, it was taken out. The liquid crystal polyester thus obtained had a flow temperature of 386 ° C. This liquid crystalline polyester is mixed with glass fiber (REV- manufactured by Nippon Sheet Glass Co., Ltd.).
8) was mixed at 40% by weight, and then granulated at a cylinder temperature of 390 ° C. using a twin-screw extruder (PCM-30 manufactured by Ikegai Tekko KK) to obtain a resin composition. After drying these resin compositions at 120 ° C. for 3 hours, using an injection molding machine (PS40E5ASE type manufactured by Nissei Plastic Industry Co., Ltd.), cylinder temperature 400 ° C., mold temperature 130 ° C., 64 mm × 13 mm × 3 mm
The rod-shaped test piece was molded. Also, using this test piece,
The flexural modulus was measured according to D790 at a distance between bending spans of 40 mm. The results are shown in Table 1.

Comparative Example 1 The liquid crystalline polyester precursor powder obtained in Synthesis Example 2 was heat treated in the same manner as in Example 1, and the flow temperature was 387 ° C.
A liquid crystalline polyester of The obtained liquid crystalline polyester was mixed with glass fiber in the same manner as in Example 1 and the bending elastic modulus was evaluated. The results are shown in Table 1.

[0032]

[Table 1]

In Example 1 using the liquid crystalline polyester precursor powder having a flowing temperature of 239 ° C., the flexural modulus was higher than in Comparative Example 1 using the liquid crystalline polyester precursor powder having a flowing temperature of 273 ° C. It can be seen that the rigidity is improved.

[0034]

According to the present invention, the high internal loss of LCP,
It is possible to provide a resin composition for an optical pickup part and an injection-molded article using the same, which is capable of producing a molded article having improved rigidity while making use of excellent melt fluidity.

Continued front page    F-term (reference) 4F071 AA43 AA48 AA84 AB01 AB28                       AB30 AD01 AE17 AF12 AH12                       BB05                 4J002 CF001 CF161 CL002 DA016                       DA026 DA066 DE136 DE186                       DJ006 DJ046 DJ056 DK006                       DL006 FA042 FA046 FD012                       FD016 GS02                 5D118 AA01 AA12 FB03 FC07 FC10                 5D119 AA01 AA35 AA38

Claims (5)

[Claims] 1. From 50% by weight to 90% by weight of a liquid crystalline polyester resin and 10% by weight to 50% by weight of an inorganic filler obtained by heat treating a liquid crystalline polyester resin precursor powder having a flow temperature of 200 ° C. to 240 ° C. A resin composition for optical pickup parts, wherein 2. A liquid crystalline polyester resin precursor powder is p
-Repeating structural unit derived from hydroxybenzoic acid 30-
80 mol%, repeating structure unit derived from at least one compound selected from the group consisting of hydroquinone and 4,4'-dihydroxybiphenyl 10-35 mol%, terephthalic acid,
The resin composition for optical pickup parts according to claim 1, which comprises 10 to 35 mol% of repeating structural units derived from at least one compound selected from the group consisting of isophthalic acid and naphthalenedicarboxylic acid. 3. A liquid crystalline polyester resin precursor powder is p
-Repeating structural unit derived from hydroxybenzoic acid 40 ~
The optical pickup according to claim 1, comprising 70 mol%, 15 to 30 mol% of repeating structural units derived from 4,4'-dihydroxybiphenyl, and 15 to 30 mol% of repeating structural units derived from terephthalic acid or a mixture of terephthalic acid and isophthalic acid. Resin composition for parts. 4. The inorganic filler is glass fiber.
3. The resin composition for optical pickup parts described in 3. 5. An injection-molded article obtained from the resin composition for optical pickup parts according to claim 1.