JPS61117730A - Substrate for disk - Google Patents

Abstract

PURPOSE:To obtain a substrate having superior dynamic performance, heat resistance and extremely superior dimensional stability and suitable for use as a substrate for a magnetic or optical disk without adding a filler for rein forcement by melting and molding a thermally liq.-crystalline polymer showing optical anisotropy during melting. CONSTITUTION:The thermally liq.-crystalline polymer made of a copolycondensate consisting of structural units represented by formulae I, II, III, IV, the thermally liq.-crystalline polymer consisting of structural units represented by formulae I, V, VI, or the thermal liq.-crystalline polymer consisting of structural units represented by formulae I, III, VII (where X is 1-5C hydrocarbon, halogen, alkoxy or phenoxy) and formula VIII (where Y is O, S, SO2, CO, alkylene or alkylidene, two rings may bond directly, and each of R1-R8 is H, halogen or hydrocarbon) is melted and molded to obtain a substrate. This substrate has superior rigidity, hardness and surface smoothness without using a reinforcing material such as glass fiber, and it is hardly deformed by a thermal change and is suitable for use as the substrate for an optical or magnetic disk.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The FJA of the present invention relates to a disk substrate molded product having excellent moldability, dimensional accuracy, and mechanical properties.

[Conventional technology]

Metals such as aluminum alloys are widely used as materials for magnetic disk substrates, and glass, synthetic resins, and the like are often used for optical disks such as magneto-optical disks and laser disks. In the case of a magnetic disk substrate, the surface or surface is 0.1-0. If foreign matter or defects exist inside the slats, the thickness of the magnetic layer will become non-uniform and the magnetic properties of the disk will deteriorate. Further, the surface of the magnetic disk is required to have extremely excellent surface smoothness. Therefore, various processes such as cutting, strain removal, and lapping are required, which requires labor and time, and the substrate itself becomes extremely expensive. Furthermore, since magnetic disks are rotated at high speeds, it is not advantageous to use materials with high specific gravity such as metals.

Therefore, it is desired that the magnetic disk substrate be made of resin.

However, in the case of synthetic resin discs, nylon, polyethylene terephthalate, polycarbonate, etc. are used, but their mechanical performance (e.g. bending strength and bending elastic modulus) is low and their coefficient of linear expansion is low. is tO-'/
Since it is on the order of 'Q, the dimensional change of the molded product due to thermal change is very large, and the basic performance as a disk substrate cannot be satisfied. Therefore, attempts are being made to improve the physical properties by adding fillers such as glass fibers and carbon fibers to compensate for these shortcomings. The presence of the filler in the vicinity makes it difficult to form a highly precise surface layer, and as a result, as described above, the thickness of the magnetic layer becomes non-uniform, degrading the magnetic properties of the disk.

Even in the case of optical disks made of glass or synthetic resin, it cannot be said that the mechanical performance is satisfactory.

[Problem that the invention seeks to solve]

As mentioned above, conventional disk substrates made of metal have problems in surface properties, heavy duty, etc., and those made of synthetic resin have problems in mechanical properties, dimensional stability, surface properties, etc.

The inventors of the present invention have conducted intensive studies to solve the problems of conventional disk substrates as described above, and have discovered that the problems can be solved by using a special resin as the substrate of the disk, and have developed the present invention. completed.

[Means for solving problems]

The gist of the present invention resides in a disk substrate obtained by melt-molding a thermoliquid crystalline polymer.

The thermoliquid crystalline polymer that can be used in the present invention may be any polymer that can be melt-molded and exhibits liquid crystallinity when melted, but is just an example.

Group, halogen atom, alkoxy group or phenoxy group is 0%
8,80t, Co, an alkylene group, an alkylidene group, or none, and R8-R8 represent a hydrogen atom, a halogen atom, or a hydrocarbon group).

~ C1 hydrocarbon group, halogen atom, alkoxy group or phenoxy group), SO! , CO1 represents an alkylene group or an alkylidene group or none, and R8 to R@ represent a hydrogen atom, a halogen atom, or a hydrocarbon group).

[V] Dicarboxylic acid unit represented by general formula (J), (wherein, at least 60 mol% of R1 is 1. Hiro-phenylene group and 17.≠Q mol% or less 2>E/, other than 4c-phenylene group) C6 to Cl11 divalent aromatic hydrocarbon group, C4 to C9 monovalent alicyclic hydrocarbon group or C2
~C, represents a covalent aliphatic hydrocarbon group. However, the hydrogen atom of the benzene ring of the aromatic hydrocarbon group (including t, a-7 dinilene group) may be substituted with a halogen atom, a C5 to C4 alkyl group, or an alkoxy group) General formula Glycol unit-0-R represented by (6)
”-0-・-・・・・(K) (wherein, R2 is C1 to C
2o U-valent aliphatic hydrocarbon group or C4-C21, co-valent alicyclic hydrocarbon group) and an oxycarboxylic acid unit represented by the general formula (L) -O-R"-C-.・・・・・・・・・(L) (In the formula, R
At least 60 moles or more of 3 is l, terphenylene group, and less than ao mole /, 4<- represents a C0 to C15 covalent aromatic hydrocarbon group other than phenylene group. However, the hydrogen atom of the benzene ring of the aromatic hydrocarbon group (l, e-yx nylene group t-containing meth) is a halogen atom, C1 to C4
may be substituted with an alkyl group or an alkoxy group).

A part of the oxycarboxylic acid unit (L) is bonded to a part of the glycol unit (K) through an ether bond to form the general formula (b) -O-R"-0-R"-C-・・・・・・・・・(M)
(In the formula, R2 and R3 are in the formulas (K) and (L), the content of the dicarboxylic acid unit (J) is 10 to qθmol, and the dicarboxylic acid unit (J) and the oxycarboxylic acid unit (L) Oxycarboxylic acid units relative to the total amount of (
The ratio of L) (L) / (J) + (L) is 3o~r
oMohchideashi, glycol unit (K) and oxycarboxylic acid unit)
Oxycarboxylic acid units relative to the total amount of (L) (
The ratio (L) / (K) + (L) of L) is 70-
The ratio of units (b) to (K) is (9)/(barrel is θ ~! θ morti is 10 molti).

A copolymerized polyester whose logarithmic viscosity +71nh measured at 30°C at a concentration of o, s 17at in a l:l (weight ratio) mixture of phenol and tetrachloroethane is equal to or higher than Q, U dl/f. etc. -CI, -Br
Or -〇H, shown in 7, 2 consists of (ΣSaku■ (BO・(Kunbegi >ocu, cu, o (indicates gigantic Σ or X-capable 匝X).

-CI or CH).

(In the formula, X represents CI, Br, CHI).

What to do.

consisting of

What will become.

etc. Among them, those shown in (I) to (V) are preferably used.

The thermoliquid crystalline polymer used in the present invention has mechanical performance and heat resistance equivalent to or superior to general-purpose engineering plastics containing fillers even without the addition of fillers. Furthermore, the thermoliquid crystalline polymer of the present invention is lO''''4
/C or less. This is smaller than general plastics and equivalent to metals, so in combination with the above-mentioned high rigidity, molded products with very excellent dimensional stability are obtained with less distortion caused by temperature changes and stress.

Further, since the thermoplastic liquid crystalline polymer used in the present invention is thermoplastic, it can be easily molded using a common molding machine at a temperature of 350C or lower. Any method such as compression molding, extrusion molding, or injection molding can be used as the molding method, but injection molding is advantageous in producing a highly accurate substrate. At this time, by applying a mirror finish to the surface of the mold, the disk substrate (required surface smoothness can be obtained).

For example, molds made from Hiroko stainless steel having a hardness of IA Hiro-414RC are known to provide highly mirror-finished surfaces.

In addition, since thermoliquid crystalline polymers exhibit crystallinity in their molten state, shearing force is applied during the forming process depending on the molding method, resulting in an oriented state, but this anisotropy of physical properties cannot be maintained in the molded disk substrate. I discovered that. This is because the disk is disc-shaped, so when KIIJ11r is compressed from the center during molding, it flows concentrically in the outer circumferential direction, which relaxes the orientation of the molecular chains, resulting in anisotropy in the physical properties. It is estimated that this will be less likely to occur. As a result, the rigidity and coefficient of linear expansion of the molded product become uniform, resulting in the advantage that even if a change in heat occurs, the molded product is less likely to be distorted.

The conditions for injection molding, etc. are as follows: The temperature should be above the melting point of the thermoliquid crystalline polymer and below the melting point +50°C, preferably below the melting point +-0°C. Although the resin flows uniformly from near the center of the disk toward the outer periphery, the present invention is not limited to the following embodiments unless the gist of the invention is exceeded.

Example 1 Terephthalic acid/4. bfrlp-acetoxybenzoic acid 9
0. Ofr, rn-acetoxybenzoic acid! r u, 0
%r, and/or Hiro-Natsuta Dibenzo rRco<t,
s 7r was charged into a polymerization tube equipped with a stirrer, and after purging with nitrogen three times, the polymerization tube was placed in an oil bath at 90°C. The mixture was stirred for 1 hour in a nitrogen stream, during which time most of the acetic acid was distilled off. Then 0. ! After creating a vacuum of Torr, the mixture was stirred for 30 minutes to complete the polymerization. Logarithmic viscosity of this polymer (solvent: phenol/tetrachloroethane-5Q
/j Q (wtac) mixed solution with concentration O, S%
, the temperature was 30C) was (7,?s (dγ/?).This polymer was heated from 260℃ to 350℃, the upper limit of the measurement temperature.
It exhibited optical anisotropy in the molten state in the temperature range up to Optical anisotropy was observed using a Nikon polarizing microscope POH model equipped with a Zeiss heat stage.

This polymer was molded into a disc shape with a diameter of QQm and a thickness of box using an injection molding machine (Model Aυ-30 manufactured by Nissei Plastics Co., Ltd.).The molding conditions were a cylinder temperature of 300-314!T°C and a center of the disc. The resin was filled from the vicinity of the part.The surface of the molded product was mirror-like.

The disk was cut into strips in the radial direction and the direction perpendicular to it, and the flexural modulus and strength were measured.

The shape of the rectangular test piece is 10XJOX/, ko (thickness) -1
, the bending speed was i m 7 minutes, the distance between the supports was Cth, and the measuring device was a Tensilon tester (Toyo Baldwin Co., Ltd. JL%).
) was used. Further, from this disk-shaped molded product, 1, C x C O x 0. Evening (thickness)
A rectangular test piece of Ig was cut out and its linear expansion coefficient was measured.

The measuring device was a thermomechanical analysis device (manufactured by Shimadzu Corporation, T
M-Co0 type) was measured in the range of 0 to 100°C.

In addition, this polymer was heated at 270℃ using a press to produce a diameter/2
m, molded into a cylinder with a height of 7.3 m, it, bky /
The heat distortion temperature was measured under aA stress.

(Toyo Seiki - Plastometer testing machine) The heat distortion temperature is indicated by the temperature at which contraction begins. Density measurements were made in a gradient tube. (JHI K-7/12) Various physical properties are shown in Table-1.

Example copolyethylene terephthalate (intrinsic viscosity o, bb), t
7. A fr, terephthal #lS t, /ir
, and N+acetoxyphenyl+3-acetoxyphthalimide//[4Pr] were charged into a polymerization tube, and polymerization was carried out in the same manner as in Example 1. Some of the polymer was insoluble and the viscosity could not be measured. Example 1
Table 7 shows the results of measuring the physical properties using the same method as above.

Example J (a) p-) Luenesulfone sulfo/acid chloride9. r? %r and dimethylformamitoco, 9 units fr
Dissolve tl-11O- in pyridine. (b) each of inphthalic acid and terephthalic acid/A & pr
Dissolve in 3-1 pyridine. (,) was added to (b) and stirred at 20°C for 70 minutes. To this solution, a solution of methylhytroquinone dissolved in 4y% rt pyridine UOtd was added dropwise over 20 minutes/N! at 20C for 3 hours! Stir downwards to react. After the reaction, the reaction solution was poured into methanol to precipitate the polymer, which was filtered and dried. The logarithmic viscosity of the obtained polymer was 0.1 (at/P).

The physical properties were measured in the same manner as in Example 1, and the results are shown in Table 7.

Example Hiroterephthalic acid lrA, Qfr1 Isophthalic acid 16.67
r, methylhydroquino74', 3. 'l fr
, 2.2-bis(terhydroxyphenyl)propane //, '1? r and 11 μm naphthalene diol/
A, 09-r and acetic anhydride/! J yr was placed in a polymerization tube equipped with a stirrer and placed in an oil bath at iso°C. After stirring for 30 minutes (U) under a nitrogen stream, the temperature was raised to 210 °C over 30 minutes. When the distillation of acetic acid and excess acetic anhydride decreased, the system was vacuumed to θ,! Torr and distilled. The polymerization was terminated after the polymerization was completed.The polymer was partially insoluble and the viscosity could not be measured.Table 7 shows the results of measuring the physical properties in the same manner as in Example.

Comparative example 6-nylon with glass fiber (NOVMID■.

toisaJo Mitsubishi Kasei (decoy), glass fiber-filled polybutylene terephthalate (NOVADUR (g)!; 01
0G) and glass fiber-filled polycarbonate (N0
VAREX 7Q CojGJθ) was molded in the same manner as in Example, and various physical properties were measured. The results are shown in Table-7.

Example! Polyethylene terephthalate (ηlnh O,1,ud
t/P (measurement conditions are the same as for the produced polymer))? 6.
? f and acetoxybenzoic acid / Of, co? was charged into a polymerization tube equipped with a stirrer. After purging the polymerization system three times with nitrogen, the polymerization tube was placed in a 5C oil bath and stirred for 1 hour under a nitrogen stream to distill most of the produced acetic acid out of the system. The pressure of the system was then reduced from normal pressure to below /Torr over 1 hour, the remaining acetic acid was distilled off, and the reaction was further carried out at K/Torr for 5 hours. The logarithmic viscosity of the produced poly 1- was o, br. Logarithmic viscosity is the natural logarithm value of relative viscosity divided by the concentration of the sample solution. In this measurement, a mixed solvent of tetrachloroethane/phenol-l/l (weight ratio) was used as the viscosity solvent, and the concentration was 0.5%. Measured by JOC. Liquid crystallinity was determined based on the presence or absence of optical anisotropy in the molten state. The apparatus used was a Zeis Nikon polarizing microscope IPOH model equipped with a heat stage.

The produced polymer showed optical anisotropy in the range of /20-J'tOC. This polymer was molded into a disc shape with an injection molding machine (manufactured by Nisseki! Resin ■, model AU-JO) with a diameter of t00 and a thickness of 100 mm. The molding conditions are cylinder temperature /9
0 to core (7C), and resin was filled from near the center of the disk. The surface of the molded product was mirror-like. The disk was cut into a rectangular shape in the radial direction and 17 cid angle direction, and the curve was determined by the elastic modulus and curvature. measured hardening.The shape of the rectangular test piece was /
OX j OX /,, 2 (thickness) 10 m 1 piece The speed was /11017 minutes, the distance between the supports was 25 M, and the measuring device used was a Tensilon tester UTM-jT type (Toyo Baldwin). Similarly, from this disc-shaped molded product, in the radial direction and in the direction perpendicular to it,
A rectangular test piece of #IjI was cut out and its linear expansion coefficient was measured. The measuring device is a thermomechanical analysis additional device (Shimadzu T
M-coO type) and -SO~io.

°C area? Measured with a trowel. The measurement of ml& was carried out using a gradient tube (JISK-71/co). Various physical properties are shown in Table 1.

Example 6 Polyethylene terephthalate oligomer (η1nh O
, / Odz/ f ) 3 JJ f p-hydroxybenzoic acid Hiroshi/i P and vinegar i stannous 0.0 Hiroshi? was charged into a polymerization tube equipped with a stirrer and purged with nitrogen three times.Then, the polymerization tube was placed in an oil bath at 4IO℃ and heated for 1 hour under a nitrogen stream.
Stir for hours. Next is acetic anhydride J6.7? was added and stirred for 1 hour and 30 minutes.

After the bath temperature was then raised to 275C while eluting acetic acid and unreacted acetic anhydride! The pressure was reduced to Torr. Furthermore, the polymerization tube was returned to normal pressure with nitrogen, and zinc acetate dihydrate o, o a
After adding 1Iy-, the mixture was stirred for 6 hours under a vacuum of Ol Torr to complete the polymerization. The logarithmic viscosity of the produced polymer is Ol
It exhibited optical anisotropy in the range of 0 to 210°C. The physical properties were measured in the same manner as in Example 5, and the results are shown in Table 1.

Comparative Examples q~6 Glass fiber-filled 6-nylon (NOVAMID■/θt
ra, yo = Ryo Kasei (Sake), glass fiber Kuborip,
V:/te, 7ri V-) (N0VADUR■!010G
JO Mitsubishi Chemical (...) and polycarbonate containing glass ff1fl (NovhRvx■7023; GJOE 9 Kasei ■) were molded in the same manner as in Example J, and the physical properties of the string were measured.

The results are shown in Table-C.

〔Effect of the invention〕

According to the present invention, a molded article can be obtained that is suitable for use as a disk substrate having excellent surface properties, light weight, mechanical properties, and dimensional stability, that is, a substrate for magnetic disks, optical disks, and the like.

Out 3 Jidai Mitsubishi Chemical Industries, Ltd. Agent: Patent Attorney Hase - (7 others)

Claims (6)

[Claims] (1) A disk substrate obtained by melt-molding a thermoliquid crystalline polymer. (2) Thermal liquid crystalline polymers are substantially (A)▲There are mathematical formulas, chemical formulas, tables, etc.▼, (B)▲▲There are mathematical formulas, chemical formulas, tables, etc.▼, (C)▲▲Mathematical formulas, chemical formulas, tables, etc. ▼, (D) ▲ Numerical formula, chemical formula, table, etc. ▼ The disk substrate according to claim 1, which is a thermoliquid crystalline polymer consisting of the structural unit ▼. (3) Thermal liquid crystalline polymers are essentially (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (E) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (F) ▲ Mathematical formulas, chemical formulas, tables, etc. The disk substrate according to claim 1, which is a thermoliquid crystalline polymer consisting of the structural unit ▼. (4) Thermal liquid crystalline polymers are essentially (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (G) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (H) ▲ Mathematical formulas, chemical formulas, tables, etc. There is ▼ (in the formula, X is C
_1 to C_8 hydrocarbon group, halogen atom, alkoxy group, or phenoxy group), (I) ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, Y is O
, S, SO_2, CO, an alkylene group, an alkylidene group, or none, and R_1 to R_8 represent a hydrogen atom, a halogen atom, or a hydrocarbon group. The disk substrate according to item 1. (5) Thermal liquid crystalline polymer has (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (D) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (G) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ , (H)▲Mathematical formulas, chemical formulas, tables, etc.▼(In the formula, X is C
_1 to C_5 hydrocarbon group, halogen atom, alkoxy group, or phenoxy group), (I) ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, Y is O
, S, SO_2, CO, an alkylene group, an alkylidene group, or none, and R_1 to R_8 represent a hydrogen atom, a halogen atom, or a hydrocarbon group. The disk substrate described in section. (6) The thermoliquid crystalline polymer is a dicarboxylic acid unit substantially represented by the general formula (J), ▲There are numerical formulas, chemical formulas, tables, etc.▼……(J) (In the formula, at least 60 of R^1 mol% or more is 1,4-
It is a phenylene group, and 40 mol% or less is a C_6 to C_1_6 divalent aromatic hydrocarbon group other than a 1,4-phenylene group, a C_4 to C_2_0 divalent alicyclic hydrocarbon group, or a C_1 to C_4_0 2 group. represents a valent aliphatic hydrocarbon group. However, the hydrogen atom of the benzene ring of aromatic hydrocarbon groups (including 1,4-phenylene group) is a halogen atom, C_
(Optionally substituted with 1 to C_4 alkyl group or alkoxy group) Glycol unit -O-R represented by general formula (K)
^2-O-......(K) (In the formula, R^2 represents a divalent aliphatic hydrocarbon group of C_1 to C_2_0 or a divalent alicyclic hydrocarbon group of C_4 to C_2_0) and general Oxycarboxylic acid unit represented by formula (L) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ...... (L) (In the formula, at least 60 mol% or more of R^3 is 1, 4-
It is a phenylene group, and 40 mol% or less represents a divalent aromatic hydrocarbon group of C_6 to C_1_6 other than the 1,4-phenylene group. However, the hydrogen atom of the benzene ring of the aromatic hydrocarbon group (including 1,4-phenylene group) may be substituted with a halogen atom, an alkyl group of C_1 to C_4, or an alkoxy group), but oxy A part of the carboxylic acid unit (L) is combined with a part of the glycol unit (K) through an ether bond to form the general formula (M) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(M) (In the formula, R^2 and R^3 have the same meaning as R^2 and R^3 in formulas (K) and (L)). The content is 10 to 40 mol%, and the oxycarboxylic acid unit (J) and the oxycarboxylic acid unit (L) are
The ratio (L)/(J)+(L) of L) is 30 to 80 mol%
and the oxycarboxylic acid unit (L) relative to the total amount of glycol unit (K) and oxycarboxylic acid unit (L).
) ratio (L)/(K)+(L) is 30 to 80 mol%, and the ratio (M)/(K) of unit (M) to glycol unit (K) is 0 to 50 mol%. , a copolymerized polyester whose logarithmic viscosity ηinh measured at 30°C at a concentration of 0.5 g/dl in a 1:1 (weight ratio) mixture of phenol and tetrachloroethane is 0.4 dl/g or more. A disk substrate according to claim 1.