JP2003113296A - Resin composition and attaching part for recording disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition excellent in flowability, stiffness and creep resistance at high temperature and to provide an attaching part for recording disk driving device having a stable attaching strength at a high operating environment temperature, especially an integrated type centering adjuster. SOLUTION: This resin composition comprises 10-40 wt.% of an inorganic filler and 2-20 wt.% of a styrene based modifier compounded to 40-88 wt.% of a polyester resin composition comprising 30-100 wt.% of a polyarylate resin and 70-0 wt.% of a polycarbonate resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent fluidity and creep resistance at high temperature, and a recording disk fixing drive device component using the resin composition, especially an integrated centering for fixing recording disks. It is about the adjuster.

[0002]

2. Description of the Related Art Audio CDs, MDs, CD-ROMs,
In a driving device (generally called a drive) for reading or writing recording discs such as CD-RW and DVD, when fixing these recording discs at fixed positions on a turntable, reading or High position accuracy is required to reduce writing errors. A component for fixing the recording disc in a fixed position is called a centering adjuster, and is composed of a centering component for determining the position of the recording disc and a chucking spring component for fixing the position by elasticity. The former requires rigidity and the latter requires creep resistance. Conventionally, a centering part made of resin and a chucking spring part made of a metal material such as stainless steel have been used in combination. However, in addition to the weight saving, in recent years, a resin composition in which a reinforcing material is mixed with a polycarbonate resin has been mainly used as an integrated centering adjuster because of a demand for an integrated structure for cost reduction. However, in the above-mentioned drive, the operating environment temperature tends to increase due to the speeding up of reading / writing and the prolonged irradiation of reading light in order to cope with the recent increase in the amount of information. A resin composition prepared by mixing a polycarbonate resin with a reinforcing material has sufficient rigidity, but the creep resistance under high operating environment temperature is insufficient, so that the recording disk cannot be fixed with a stable mounting force. was there. On the other hand, the present inventors have tried to improve the resin composition using a polyarylate resin. However, with this product, although the creep resistance is improved, the fluidity during molding is somewhat insufficient, and the amount of molding shrinkage tends to increase for precision molded product applications or sink marks are likely to occur. was there. If high-speed, high-pressure molding or a mold is rapidly cooled in order to suppress these, there is a problem that warp is likely to occur due to internal strain.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, improves the fluidity of the resin composition without impairing the creep resistance in a high temperature region, and a recording disk fixing using the same. (EN) Provided is an integrated centering adjuster in which a drive device component, in particular, a centering component and a chucking spring component are combined.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a polyester resin composition comprising a polyarylate resin and a polycarbonate resin contains a specific amount of an inorganic reinforcing material and a styrene-based fluid. The present invention has been accomplished by finding that the object can be achieved by incorporating a property improving agent. That is, the gist of the present invention is as follows. (1) 40 to 88% by mass of a polyester resin composition comprising 30 to 100% by mass of polyarylate resin and 70 to 0% by mass of a polycarbonate resin, 10 to 40% by mass of an inorganic filler, and 2 to 20% by mass of a styrenic modifier. % Of the resin composition. (2) The inorganic filler is at least one selected from glass fiber, glass beads and glass flakes (1)
The resin composition described. (3) The resin composition according to (1) or (2) above, wherein the styrene-based modifier is a styrene / N-phenylmaleimide copolymer. (4) A recording disk fixing drive device component using the resin composition described in (1) to (3) above. (5) The above (4) which is an integrated centering adjuster.
A drive device component for fixing the recording disk described.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The resin composition in the present invention comprises a polyester resin composition prepared by mixing a polyarylate resin and a polycarbonate resin, an inorganic filler, and a styrene-based modifier. When the total amount of the polyester resin composition is 100% by mass, the content of the polyarylate resin is 30 to 100% by mass.
It is necessary to be in the range of, and preferably 50 to 100% by mass. 30% by weight of polyarylate resin
If it is less than the above range, the effect is poor in improving the creep resistance in the high temperature region. The compounding amount of the inorganic filler needs to be 10 to 40% by mass of the whole resin composition, and is 20 to 3%.
More preferably, it is in the range of 5% by mass. Compounding amount is 1
If it is less than 0% by mass, the rigidity is insufficient, and 40% by mass
If it exceeds, there is a problem in manufacturing that pelletization by kneading and extrusion becomes difficult.

It is necessary that the amount of the styrene-based modifier is 2 to 20% by mass, and more preferably 5 to 10% by mass. If the content is less than 2% by mass, the effect of improving the fluidity is insufficient, and if it exceeds 20% by mass, the physical properties of the molded product deteriorate.

The polycarbonate resin used in the present invention comprises a bisphenol residue unit and a carbonate residue unit. Examples of the raw material bisphenols include 2,2-bis (4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4)
-Hydroxyphenyl) propane, 1,1-bis (4-
Hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) decane, 1,4-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclododecane, 4,4′-dihydroxydiphenyl ether,
4,4'-dithiodiphenol, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-dihydroxydiphenyl ether and the like can be mentioned. In addition, US Patent Specification No. 2,99
9,835, 3,028,365, 3,33
The diphenols described in 4,154 and 4,131,575 can be used. These may be used alone or in combination of two or more. Examples of the precursor for introducing the carbonate residue unit include phosgene and diphenyl carbonate.

The polyarylate resin is an aromatic polyester polymer composed of an aromatic dicarboxylic acid residue unit and a bisphenol residue unit. Examples of the bisphenols as raw materials include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,
5-dimethylphenyl) propane, 2,2-bis (4-
Hydroxy-3,5-dibromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ether,
4,4'-dihydroxydiphenyl sulfide, 4,
4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenylmethane, 1,1-bis (4-hydroxyphenyl) cyclohexane and the like can be mentioned. These may be used alone or in combination of two or more.

Preferable examples of the raw material of the aromatic dicarboxylic acid residue unit include terephthalic acid and isophthalic acid. Particularly, when they are used as a mixture, the polyarylate resin obtained has melt processability and overall performance. In terms of, favorable results can be obtained. The mixing ratio (terephthalic acid / isophthalic acid) can be arbitrarily selected, but the molar fraction is preferably in the range of 90/10 to 0/100, more preferably 70/30 to 0/100, It is particularly preferably 50/50 to 0/100. If the mixed mole fraction of terephthalic acid exceeds 90%, it becomes difficult to obtain a sufficient degree of polymerization.

The polycarbonate resin used in the resin composition of the present invention preferably has an inherent viscosity of 0.40 to 0.64. If it exceeds 0.64, the melt viscosity becomes high and it becomes difficult to carry out kneading extrusion and injection molding. 0.4
If it is less than 0, the impact strength of the obtained molded article tends to be insufficient.

The polyarylate resin used in the resin composition of the present invention preferably has an inherent viscosity of 0.50 to 0.74. If it exceeds 0.74, the melt viscosity becomes high and it becomes difficult to carry out kneading extrusion and injection molding. 0.50
If it is below the range, the impact strength of the obtained molded article tends to be insufficient. The logarithmic viscosity of the entire component (organic component) including the polyester resin and the styrenic modifier is 0.48 to 0.6, excluding the inorganic filler from the resin composition of the present invention.
It is preferably 0, and more preferably 0.48 to 0.55. If it exceeds 0.60, the melt viscosity becomes high and it becomes difficult to carry out kneading extrusion and injection molding. If it is less than 0.48, the impact strength of the obtained molded article tends to be insufficient.

The inorganic filler to be added to the resin composition of the present invention is not particularly limited, and examples thereof include glass, mica, clay and the like, and glass is effective in improving rigidity. Fibers, glass beads, and glass flakes are more preferable, and among them, glass flakes are particularly preferable because the warpage of the molded product can be reduced.

Examples of the styrenic modifier compounded in the resin composition of the present invention include styrene modified products such as polycarbonate and polyarylate, and styrene / N-phenylmaleimide copolymers. From the viewpoint of heat resistance stability, a styrene / N-phenylmaleimide copolymer is most preferable. The molecular weight is preferably 100,000 or more.

In addition to the above, a pigment,
A weathering agent, an antioxidant, a flame retardant, a release agent, a sliding agent such as ultra-high molecular weight polyethylene, a fluororesin and the like can be added. In the resin composition of the present invention, the method of blending the polyarylate resin, the polycarbonate resin, the inorganic filler and the styrene-based modifier is not particularly limited, and each component is uniformly dispersed in the resin composition. You just need to be in a state of being. Specifically, a method in which a polyarylate resin, a polycarbonate resin, an inorganic filler, and a styrene-based modifier are uniformly blended using a tumbler or a Henschel mixer, and then melt-kneaded to form pellets can be mentioned.

Further, in the production of the resin composition of the present invention, in order to reduce the breakage of the inorganic filler in the kneading step, it is preferable to perform melt kneading using an extruder equipped with a side feeder. At this time, it is preferable that the polyarylate resin, the polycarbonate resin, and the styrene-based modifier are charged from the main supply port, and the inorganic filler is charged from the side feeder.

Since the pellets of the obtained resin composition have good fluidity, it is possible to obtain a recording disk fixing drive device part such as an integral centering adjuster by a conventional injection molding method. Since this recording disk fixing drive device component has sufficient rigidity and creep resistance in a high temperature region, when used in an integrated centering adjuster or the like, the recording disk can be fixed with a stable mounting force. It is possible to maintain excellent positional accuracy.

[0017]

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples. 1. Raw material, polyarylate resin; U-powder (logarithmic viscosity 0.64) manufactured by Unitika. Hereinafter referred to as PAR. -Polycarbonate resin; Sumitomo Dow Caliber 200-3
0 (logarithmic viscosity 0.44). Hereinafter referred to as a PC.・ Glass flake; Nippon Sheet Glass REFG-301, average diameter 1
40 μm, average aspect ratio 30. Hereinafter referred to as Gf.・ Glass beads: Toshiba Ballotini EGB731A, particle size 1
8 μm. Hereinafter, referred to as Gb. Glass fiber; EPG 70M-80A manufactured by Nippon Electric Glass Co., Ltd., fiber diameter 9 μm, fiber length 70 μm. Hereinafter referred to as Gd. -Styrene / N-phenylmaleimide copolymer; MS-NA manufactured by Denki Kagaku Kogyo. Hereinafter referred to as SPMI. 2. Evaluation method (1) Logarithmic viscosity 1,1,2,2-tetrachloroethane was used as the solvent,
The value at 1.0 g / dl and a temperature of 25 ° C. was measured. When measuring the logarithmic viscosity of the organic component, the resin composition was dissolved in a solvent so that the amount of the organic component was 1.0 g / dl, and the inorganic filler was filtered off. In Comparative Examples 3 and 4 described later, it was not possible to obtain the amount of pellets required for molding evaluation, but it was possible to sample the amount (several grams) required for evaluation of logarithmic viscosity. Was used. (2) Injection pressure for pressure control using a bar-shaped mold with a fluidity of 1 mmt
An injection molding test was performed at 110 MPa, and the flow length was measured. (3) Flexural strength and flexural modulus Measured according to ASTM D790. (4) Izod impact value Measured according to ASTM D256. (5) Deflection temperature under load According to ASTM D648, the load was measured at a load of 0.46 MPa. (6) Creep resistance ASTM strips (width 12.7 mm x length 40.0 mm x
Using a thickness of 3.2 mm), the strain rate was 1.0%, the relaxation elastic modulus after 100 hours at an ambient temperature of 80 ° C., and the instantaneous elastic modulus were measured for evaluation. The larger the ratio of the relaxation elastic modulus to the instantaneous elastic modulus, the better the creep resistance. (7) Amount of warpage Square flat plate
A molding test of a die of mm × 60.0 mm × thickness 11 mm) was performed. The molding condition is that the molding shrinkage in the flow direction is 0.2%.
It was set to be ~ 0.3%. The obtained flat plate molded article was placed on a horizontal table with the convex side up and the height was measured. The amount of sled is (sledge height / diagonal length of flat plate) x 100
It was evaluated by. (8) As a mounting force test piece, including the chucking spring portion, 15.
Several kinds of integrated centering adjusters having an outer diameter within a dimensional tolerance of 20 to 15.22 mm and different chucking spring thicknesses were prepared.
The mounting force was measured by mounting a disc having an inner diameter standard of 5 mm (the mounting allowance was 0.05 to 0.22 mm depending on the centering adjuster outer diameter and the disc inner diameter).
Range). The mounting force was measured with a universal tensile tester manufactured by Intesco using a dedicated jig. Initially, a standard 15.10 mm inner diameter disc was mounted to measure the initial mounting force. If the initial mounting force is 1.50 N or more, the product passes. Next, an integral type centering adjuster having an initial mounting force of 1.50 N or more was selected to have a minimum chucking spring thickness and used as a test sample. For this disc, remove the disc with an inner diameter of 15.10 mm that had been attached to the disc, and the inner diameter will be the largest at 15.00.
Mount a mm disc and hold it for 10 minutes at an ambient temperature of 80 ° C.
I left it for 0 hours. After this, the inner diameter 1 with the smallest mounting allowance
The disc was mounted on a 5.15 mm disc and the mounting force was measured.
If the mounting force at this time is 0.5 N or more, it passes.

Example 1 35 parts by mass of PAR, 35 parts by mass of PC and 10 parts by mass of SPMI were used as a phosphorus heat-resistant agent (PEP-3 manufactured by Asahi Denka Kogyo KK).
6) 0.1 parts by mass and phenolic antioxidant (irganox 101 manufactured by Ciba Specialty Chemicals)
0) Using a continuous constant-flow feeder manufactured by Kubota Co. together with 0.05 parts by mass, it was supplied to the main feed port of a co-directional twin-screw extruder with a side feeder (TEM-37BS manufactured by Toshiba Machine Co., Ltd.).
Further, 20 parts by mass of Gf was supplied from the side feeder. Melt-kneading is performed at a resin temperature of 320 ° C. and a discharge rate of 14 kg / hr. The resin composition drawn in the form of a strand from a nozzle is passed through a water bath to cool and solidify, cut with a pelletizer, and dried with hot air at 120 ° C. for 12 hours. By doing so, pellets of the resin composition were obtained. Then, the obtained resin composition pellets are treated with an injection molding machine (IS manufactured by Toshiba Machine Co., Ltd.
100E-3S) at a resin temperature of 340 ° C.,
Various test pieces were produced. Measure the flow length of the bar mold,
The fluidity was evaluated. Further, the test pieces for measuring physical properties were left at room temperature for one day or more, and then mechanical strength, thermal properties, creep resistance, and warpage amount were examined. In addition, an integrated centering adjuster was manufactured and the mounting force was measured.

Example 2 The same melt kneading as in Example 1 was carried out except that 49 parts by mass of PAR and 21 parts by mass of PC were used in Example 1 to obtain pellets of the resin composition. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 3 The same melt kneading as in Example 1 was carried out except that 63 parts by mass of PAR and 7 parts by mass of PC were used in Example 1 to obtain pellets of the resin composition. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 4 In Example 1, 70 parts by weight of P as polyester was used.
Melt kneading was performed in the same manner as in Example 1 except that only AR was used to obtain pellets of the resin composition. Molding temperature 3
The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1 except that the temperature was 50 ° C.

Example 5 The same melt kneading as in Example 1 was carried out except that 42 parts by mass of PAR, 18 parts by mass of PC and 30 parts by mass of Gf were used in Example 1, to obtain a resin composition. Pellets were obtained.
The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 6 Pellets of a resin composition were obtained by performing the same melt-kneading as in Example 1 except that 25 parts by mass of PAR and 45 parts by mass of PC were used in Example 1. Molding temperature 32
The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1 except that the temperature was 0 ° C.

Example 7 The same melt kneading as in Example 1 was carried out except that 56 parts by mass of PAR, 24 parts by mass of PC and 10 parts by mass of Gf were used in Example 1, to obtain a resin composition. Pellets were obtained.
The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 8 In Example 1, 54.5 parts by weight of PAR, 23.5
Melt-kneading was performed in the same manner as in Example 1 except that PC of 2 parts by mass and SPMI of 2 parts by mass were used to obtain pellets of the resin composition. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 9 Example 1 was repeated except that 42 parts by mass of PAR, 18 parts by mass of PC and 20 parts by mass of SPMI were used in Example 1.
The same melt-kneading was carried out to obtain pellets of the resin composition. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Example 10 The same melt kneading as in Example 1 was carried out except that 10 parts by mass of Gb and 10 parts by mass of Gd were used in place of Gf in Example 1, to obtain pellets of the resin composition. Obtained. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1. Table 1 collectively shows the evaluation results of Examples 1 to 10.

[0028]

[Table 1]

Comparative Example 1 In Example 1, 70 parts by mass of PC was used without PAR.
And 10 parts by mass of SPMI are directly supplied to the extruder, 20 parts by mass of Gf are supplied from the side feeder, and the temperature is 30
The same procedure as in Example 1 was carried out except that the kneading was carried out at 0 ° C. to obtain pellets of the resin composition. Molding temperature 30
A test piece and an integral centering adjuster were produced and evaluated in the same manner as in Example 1 except that the temperature was 0 ° C.

Comparative Example 2 In Example 1, 59.5 parts by mass of PAR, 25.5
Melt-kneading was performed in the same manner as in Example 1 except that parts by mass of PC and 5 parts by mass of Gf were used to obtain resin composition pellets. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Comparative Example 3 Melt kneading was carried out in the same manner as in Example 1 except that 28 parts by mass of PAR, 12 parts by mass of PC and 50 parts by mass of Gf were used in Example 1, but from an extruder. The discharged resin composition was cut into pieces, and it was difficult to take it into a strand shape, and pellets required for molding evaluation could not be obtained.

Comparative Example 4 Example 1 was repeated except that 35 parts by mass of PAR, 15 parts by mass of PC and 30 parts by mass of SPMI were used in Example 1.
Although the same melt-kneading was carried out as in the above, the resin composition discharged from the extruder was cut into pieces and it was difficult to take it into a strand form, and pellets required for molding evaluation could not be obtained.

Comparative Example 5 A resin composition was prepared by the same melt kneading as in Example 1 except that 56 parts by mass of PAR, 24 parts by mass of PC and 0.5 parts by mass of SPMI were used. The product pellet was obtained. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Comparative Example 6 The same melt-kneading as in Example 1 was carried out except that 39 parts by mass of PAR, 39 parts by mass of PC were used, SPMI was not added, and 22 parts by mass of Gf were supplied. Then, pellets of the resin composition were obtained. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

Comparative Example 7 The same melt-kneading as in Example 1 was carried out except that 55 parts by mass of PAR, 23 parts by mass of PC were used, SPMI was not added and 22 parts by mass of Gf were supplied. Then, pellets of the resin composition were obtained. The test piece and the integrated centering adjuster were evaluated in the same manner as in Example 1.

The results of Comparative Examples 1 to 7 are shown in Table 2.

[0037]

[Table 2]

Examples 1 to 10 of the present invention are resin compositions which are excellent in fluidity, flexural strength, flexural modulus, Izod impact value and deflection temperature under load, and at the same time have small warpage and excellent creep resistance. I understand. In addition, all the integrated centering adjusters using this composition showed a sufficient value in the mounting force even after 80 ° C. × 100 hours.

The resin composition of Comparative Example 1 had an amount of PAR falling outside the range of the present invention, so that although it had excellent fluidity, it had low deflection temperature under load and creep resistance, and integrated centering using this resin composition. The initial mounting force of the adjuster satisfied the acceptance criteria, but the mounting force after 80 ° C. × 100 hours decreased, and the adjuster was rejected. The resin composition of Comparative Example 2 was excellent in fluidity and creep resistance because the compounding amount of the inorganic filler was outside the range of the present invention, but the bending strength,
The flexural modulus was low and the warpage was large. If this is an integrated centering adjuster, the mounting force will be 8
The value after 0 ° C. × 100 hours satisfied the acceptance criteria, but even the sample with the largest chucking spring thickness had a low initial value and did not satisfy the acceptance criteria. In the resin composition of Comparative Example 3, since the blending amount of the inorganic filler was outside the range of the present invention, stable operation could not be performed in the melt-kneading step, and pellets required for characteristic evaluation could not be obtained. In the resin composition of Comparative Example 4, since the SPMI content was outside the range of the present invention, stable operation could not be performed in the melt-kneading step, and pellets required for characteristic evaluation could not be obtained. The resin composition of Comparative Example 5 had a flexural strength,
The resin composition was excellent in flexural modulus, Izod impact value, and deflection temperature under load, and was also excellent in creep resistance. In addition, all the integrated centering adjusters using this composition showed a sufficient value in the mounting force even after 80 ° C. × 100 hours. However, since the compounding amount of SPMI was outside the range of the present invention, the fluidity at the time of molding was poor and the warpage was large. The resin compositions of Comparative Examples 6 and 7 were excellent in mechanical properties, deflection temperature under load, and creep resistance, but because SPMI was not compounded, they had poor fluidity during molding and large warpage. .

[0040]

The resin composition of the present invention is excellent in fluidity, rigidity and creep resistance at high temperature and has a small warpage. Therefore, by using this, a stable mounting force is provided even at a high operating environment temperature. It is possible to obtain a drive disk component for fixing a recording disk, particularly an integrated centering adjuster. Then, it becomes possible to fix the recording disk such as the optical disk to the fixed position of the turntable with a stable mounting force.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F071 AA22X AA37X AA48 AA50                       AA76 AB28 AB30 AD01 AH16                       BA01 BB05 BC07                 4J002 BC043 CF16W CG00X DJ036                       DJ056 DL006 FA016 FA046                       FA086 GM00

Claims (5)

[Claims] 1. A polyester resin composition composed of 30 to 100% by mass of a polyarylate resin and 70 to 0% by mass of a polycarbonate resin, 40 to 88% by mass, and an inorganic filler 1.
A resin composition comprising 0 to 40 mass% and a styrenic modifier 2 to 20 mass%. 2. The resin composition according to claim 1, wherein the inorganic filler is at least one selected from glass fiber, glass beads and glass flakes. 3. The resin composition according to claim 1, wherein the styrene-based modifier is a styrene / N-phenylmaleimide copolymer. 4. A drive unit for fixing a recording disk, which is made of the resin composition according to claim 1. 5. The recording disk fixing drive device component according to claim 4, which is an integral centering adjuster.