JPS63291916A - Resin for optical base material - Google Patents

Abstract

PURPOSE:To obtain the titled resin useful for optical disc substrate, etc., having excellent dimensional stability, double refraction and strength, consisting of a reaction product of a 4,4'-bis(hydroxyethyl)bisphenol, etc., and a polyisocyanate, having a specific urethane unit structure. CONSTITUTION:A diol compound such as a 4,4'-bis(hydroxyethyl)bisphenol and a polyisocyanate compound are heated and extruded by the use of an extruder to give the aimed resin comprising a polymer having a urethane unit structure shown by formula I [A is group shown by formula II (R is 1-3C bifunctional aliphatic group or sulfone; X is 1-15C lower alkyl, Cl or Br; m is 0-2 integer; p and q are 0-2 integer) or group shown by formula III (U is 1-15C bifunctional aliphatic group; Y is mere bond or COO; S is 1-20 integer; T is 5-10 integer); B is tolyene or group shown by formula IV; n is 5-300] as a repeating unit.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a material for optical equipment, and particularly to a resin material suitable for digital audio discs, optical memory discs, video discs, optical lenses, and the like.

[Conventional technology] Conventionally, materials for optical transparent molded products have been used for light transmittance,
Acrylic resins and polycarbonates are the most preferred and have been put into practical use in terms of moldability and the like. As the molding method, injection molding or compression molding is usually used.

However, especially as a material for disk substrates, acrylic resin has a high water absorption property, and has the problem of dimensional changes due to moisture absorption, warpage of the substrate, or cracks due to long-term repetition of drying and moisture absorption.

On the other hand, polycarbonate has low water absorption and a high glass transition temperature, but orientation tends to occur during injection molding or compression molding, and its birefringence is not sufficient. In order to eliminate the above-mentioned drawbacks, a polycarbonate having a clay average molecular weight of 15.000 to 18°OOO has been proposed (Japanese Patent Application Laid-open No. 180553/1982), but this is still insufficient and has large birefringence. However, there are still limits to its use.

Particularly in precision optical systems used for reading and writing information using light such as lasers, birefringence in optically transparent molded products is a major problem, and the development of plastics with lower birefringence is desired. Ta.

[Problems to be Solved by the Invention] The present invention attempts to solve these drawbacks of the prior art, and uses a molding method with high productivity such as injection molding or compression molding, and The purpose of this invention is to provide a material suitable for optical disk substrates, optical memories, optical lenses, etc., which is excellent in terms of substrate warpage, heat softening resistance, and birefringence.

[Means for solving the problem] In order to achieve the above object, the present invention has the following configuration.

[A resin for optical substrates comprising a polymer having a urethane unit structure represented by the following general formula [I] as a repeating unit.

Thousand-A -00CHN-B -NHCOO→Bottom
[I] [However, A and B have the following structures.

or (in component A, R is a divalent aliphatic, alicyclic or sulfone having 1 to 3 carbon atoms,
/L/ group, C1 or 3r, an integer of n-5 to 300, an integer of m-0 to 2, p and q represent an integer of O to 2, U is a divalent aliphatic group of C1 to 15, aliphatic It is a ring group or a]-substituted alkyl group, Y is a simple bond or -coo-, s is an integer of 1 to 20, and T is an integer of 5 to 10. ) B: One or more organic groups selected from. ]” In order to impart the structure of A, the following compounds can be used during production. Specifically, bis(4-hydroxyethylphenyl)methane, 1,1-bis(4-hydroxyethylphenyl)ethane, 2,2-
Bis(4-hydroxyethylphenyl)propane, bis(4-dihydroxyethylphenyl)methane, 2,2-
Bis(4-dihydroxyethylphenyl)ethane, 2,
2-bis(4-dihydroxyethylphenyl)propane, 4.4-bis(hydroxyethyl)bisphenol A
, 4.4-bis(dihydroxyethyl)bisphenonyl A, 4.4-bis(hydroxyethyl)tetrabromobisphenol A, bis(4-hydroxyethylphenyl)sulfone, bis(dihydroxyethylphenyl)sulfone, 2゜2-bis Examples include (4-cyclohexanol)propane, 2,2-bis(4-hydroxyethylcyclohexyl)propane, and 2,2-bis(4-hydroxyethylcyclohexyl)sulfone.

In the above, 4.4-bis(hydroxyethyl)bisphenol A, 4.4-bis(hydroxyethyl)tetrabromobisphenol A1 bis(4-hydroxyethylphenyl)sulfone, 2゜2-bis(4-cyclohexanol)propane is particularly effective.

In order to impart the structure B, the following compounds are used during production. Specifically, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, 4,4-isopropylidenediphenyl diisocyanate, naphthalene diisocyanate, hydrogenated product of tolylene diisocyanate, hydrogenated product 1 of diphenylmethane diisocyanate, water of xylylene diisocyanate. Additives etc. are useful.

Furthermore, as an isocyanate compound, 1,3-bis(
α,α-dimethyl-isocyanatomethyl)benbin,
Another name may be used: tetramethylxylylene diisocyanate. This compound is a non-yellowing diisocyanate having a benzene ring in the molecule, and the isocyanate group is shielded by two methyl groups. Therefore,
Although the isocyanate group is adjacent to the benzene ring, it is resistant to yellowing.

A urethane resin is produced using the above-mentioned components in a conventional manner. The urethane reaction may be carried out in a suitable solvent, or for compounds with a low melting point, it may be carried out directly. The OH group in the A component and the NGO group in the 8 components are reacted at an appropriate ratio, but usually the NGO10H ratio is preferably around 1.0, and the reaction may be performed using a catalyst or chain extender if necessary. Can be done. The reaction temperature is 50-2
oo'c is appropriate. Particularly preferred is 70 to 120'C.

On the other hand, the molecular weight is selected depending on the purpose. That is, the melt viscosity of the urethane resin of the present invention needs to be selected in accordance with the conditions of injection molding, compression molding, etc., while taking birefringence into consideration. For injection molding, the molding temperature is 150-25
0''C is preferable, and the viscosity during molding is suitably around i ooo poise.

The structure of the urethane resin constituted in the present invention is FT-
IR, NMR, elemental analysis, GC, HPLC.

It can be easily confirmed by conventional analytical means such as GC-MS.

In producing the material for optical equipment of the present invention, conventional additives such as antioxidants and ultraviolet absorbers may be added.

Furthermore, a feature of the present invention is a method for producing urethane resin. That is, in the present invention, the above-mentioned diol compound and isocyanate compound can be put into an extruder, for example, and the urethane resin can be produced while being heated and extruded in the extruder. A molding machine that is directly connected to the extruder allows the urethane resin to be molded as it is without having to take it out. Therefore, the molded curtain plate is extremely clean, and it is possible to prevent the contamination of dirt, dust, etc. that would adversely affect recording characteristics and impair high quality.

This is one of the problems with conventional acrylic resins and polycarbonates, and great efforts are being made by manufacturers, but this problem has been solved with the present invention.

In the present invention, the urethane reaction may be performed using a catalyst or may be carried out as it is without using a catalyst. The isocyanate used in the present invention is not highly reactive. Rather, it is one of the slower isocyanates. Therefore, sufficient defoaming can be achieved even at temperatures around 100°C.

Further, in the present invention, the polycarbonate may be a terminal alcoholic polycarbonate. When such end-stopped polymers are used, for example, 4.4'-dihydroxydiphenylalkanes are used to create polymers of such structure.

Examples of 4.4°-dihydroxydiphenylalkanes include bis(4-hydroxyphenyl)methane, 1.1-
Bis(4-hydroxyphenyl)ethane, 2゜2-bis(4-hydroxyphenyl)propane, 2゜2-bis(
4-hydroxyphenyl)butane, 1,1-bis(4
-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-dichlorophenyl)propane, -Hydroxy-
3,5-dimethylphenyl)propane, 2゜2-bis(
These include 4-hydroxy-3,5-diethylphenyl)propane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, and bis(4-hydroxyphenyl)-diphenylmethane.

Compounds used as terminal capping agents include hydroxyethylphenol, hydroxyethylphenol, hydroxypropylphenol, hydroxylaurylphenol, hydroxyoctylphenol, methanol hydroxybenzoate, ethanol hydroxybenzoate, propatool hydroxybenzoate, and octylbenzoate. Tool, hydroxybenzoic acid octatool, etc.

To obtain the above terminal alcoholic polycarbonate,
Manufactured by interfacial polymerization method. The average degree of polymerization of the terminal alcoholic polycarbonate is suitably in the range of 5 to 10. When the average Φ degree is larger than this range, the melt viscosity becomes too high and the birefringence of the molded substrate tends to increase. On the other hand, if the average degree of polymerization is smaller than the above range, there is a problem that the mechanical properties of the substrate are significantly deteriorated. Therefore, preferred polycarbonates are terminal alcoholic polycarbonate oligomers.

On the other hand, as the isocyanate compound to be reacted with the terminal alcoholic polycarbonate oligomer, a bifunctional diisocyanate compound can be used. In particular, compounds having an aromatic ring or a cyclohexane ring are useful. Examples include tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated products of tolylene diisocyanate, hydrogenated products of diphenylmethane diisocyanate, and hydrogenated products of xylylene diisocyanate.

The OH group of the above terminal alcoholic polycarbonate oligomer and the NCO of the bifunctional diisocyanate compound
A urethane resin is produced by reacting with the group. The urethane reaction may be carried out in a suitable solvent or directly while melting, according to a conventional method.

The urethane resin obtained in the present invention has a lower water absorption than acrylic resins used as conventional optical transparent molding materials, and has better birefringence than polycarbonate. Therefore, when the urethane resin is used as a material for various optical devices, it operates stably under various conditions.

Therefore, the material of the present invention can be effectively used for digital audio discs, optical memory discs, video discs, and optical lenses.

[Example code] Next, the present invention will be explained by examples.

EXAMPLES In order to clarify the gist of the present invention, Examples are given below, but the present invention is not limited to these Examples. In addition, in Examples and Comparative Examples, characteristics were measured by the following test method.

■ Birefringence: The molded substrate was sandwiched between deflection plates, and birefringence was determined by visual observation.

■ Water absorption rate: According to JIS K-7209. In other words, a test piece of 50mm x 50mm x 3Qmm was placed at 23'c.
The water absorption rate was measured after 24 hours.

■ Tg: By DSC (differential scanning calorimetry) method,
The midpoint of the temperature range in which the amount of heat changes was determined as Tg. Hereinafter, it will be expressed as a glass transition point.

Example 1 4.4-bis(hydroxyethyl)bisphenol A6
2.4 parts by weight, diphenylmethane diisocyanate 3
7.61 parts of ffi was dissolved in a dimethylformamide solvent, stirred uniformly, and heated to 100°C to carry out an addition reaction to produce a urethane resin.

After heating this solution to 200°C and desolventizing it in an extruder, it was subsequently injection molded under conditions of a cylinder temperature of 200°C and a mold temperature of 80°C.
A 2 mm transparent disk substrate was made. The water absorption rate of this substrate was 0.6%, which was extremely low compared to 1.2% of the acrylic resin, and the birefringence was also good. The results of the characteristics are shown in Table 1.

Example 2 2.2-bis(4-cyclohexanol)propane 5
6.511 parts, xylylene diisocyanate 43.5
A disk substrate was prepared according to Example 1 using parts by weight. The water absorption rate of this substrate was 0.6%, and the birefringence was also good. The results of the characteristics are shown in Table 1.

Example 3 77.1 parts by weight of 4.4-bis(hydroxyethyl)tetrabromo bisphenol A and 22.9 parts by weight of xylylene diisocyanate were used.

A disk substrate was produced according to Example 1. The water absorption rate of this substrate is 0.3%, which is comparable to polycarbonate.
Birefringence was also good. The results of the characteristics are shown in Table 1.

Example 4 Bis(4-hydroxyethylphenyl)sulfone 57
．． 2 parts by weight, hydrogenated diphenylmethane diisocyanate
A disk substrate was produced according to Example 1 using 42.7 parts by weight. The water absorption rate of this substrate is 0.5%,
Birefringence was also good. The results of the characteristics are shown in Table 1.

Example 5 Bis(4-hydroxyethylphenyl)sulfone 59
．． A disk substrate was prepared according to Example 1 using 42.7 parts by weight of 0.0 xylylene diisocyanate.

The results of the characteristics are shown in Table 1.

Comparative Example 1 A disk substrate having a diameter of 12α and a thickness of 1.2 m was obtained by injection molding using polymethyl methacrylate.

The results of the characteristics are shown in Table 1. Although it has good birefringence, it has a drawback of high water absorption.

Comparative Example 2 Injection molded using polycarbonate, diameter 12 cm
A disk substrate with a thickness of 1.2 ai was obtained. The results of the characteristics are shown in Table 1. Excellent water absorption, but poor birefringence.

Table 1 Polymer properties Example 6 4.4-bis(hydroxyethyl)bisphenol A
(OH value 350) 56.4 parts ffi, as an isocyanate compound, 1,3 bis(α,α dimethyl isocyanate methyl)benzene (NCO content 34.4w
A mixture of 43.6 parts by weight of t%) and 0.011 parts by weight of dibutyl tin dilaurate was put into an extruder directly connected to the molding machine, and heated at 140°C for about 10 minutes while the extruder was running. An addition reaction was performed to produce a urethane resin.

This polymer is heated to 200℃ and sent into a cylinder.
Injection molded at a mold temperature of 80℃, diameter 12cm.
A transparent disk substrate with a thickness of 1.2 mm was made.

The water absorption rate of this substrate is 0.5%, and the water absorption rate of acrylic resin is 1%.
．． The birefringence was extremely low compared to 2%, and the birefringence was also good. The results of the characteristics are shown in Table 2.

Example 7 2.2-bis(4-cyclohexanol)propane (O
8 valent 460) 49.6 parts by weight, 1,3 bis (α, α dimethyl isocyanate methyl) benzene 50.4 parts by weight 1
A disk substrate was prepared according to Example 1 using a mixture of 0.01 parts by weight of dibutyl tin dilaurate and 0.01 parts by weight of dibutyltin dilaurate. The water absorption rate of this substrate was 0.6%, and the birefringence was also good. The results of the characteristics are shown in Table 2.

Example 8 A disk substrate was prepared according to Example 1 using 72.0 parts by weight of 4.4-bis(hydroxyethyl)tetrabromobisphenol A (OH value 178), 28.01 parts by weight of xylylene diisocyanate, and dibutyltinsila. Created. The water absorption rate of this substrate was 0.3%, which was comparable to polycarbonate, and the birefringence was also good. The results of the characteristics are shown in Table 2.

Comparative Example 3 Injection molding using polymethyl methacrylate, diameter
A disk substrate of +2 cm and thickness of 1.2M111 was obtained.

The results of the characteristics are shown in Table 1. Although it has good birefringence, it has a drawback of high water absorption.

Comparative Example 4 Injection molded using polycarbonate, diameter 12 cm,
A disk substrate with a thickness of 1.2M was obtained. Table 1 shows the characteristics results.
Shown below. Excellent water absorption, but poor birefringence.

Reference Example 1 Sodium hydroxide 3.7- was dissolved in water 42Q and heated at 20°C.
2.2-(4-bishydroxyphenyl) while keeping
7.3 kq of propane (BPA) and 8 g of hydrosulfide were dissolved.

Add to this 433g of 12-hydroxylauric acid chloride.
was added and then 2.5 to 9 of phosgene was bubbled over 60 minutes.

After the phosgene injection was completed, the reaction solution was vigorously stirred to emulsify it, and after emulsification, 8 g of triethylamine was added and the mixture was stirred for about 1 hour to allow polymerization.

The polymerization solution was separated into an aqueous phase and an organic phase, and the organic phase was neutralized with phosphoric acid. After repeating water washing until the pH of the washing solution became neutral, 35M of isopropanol was added to the washing solution. The polymer was precipitated. The precipitate was filtered and then dried to obtain a polycarbonate oligomer as a white powder. The average degree of polymerization of this oligomer was about 7.

Example 9 89 parts by weight of the terminal alcoholic polycarbonate oligomer obtained in Reference Example 1 and 11 parts by weight of diphenylmethane diisocyanate were dissolved in a solvent of dimethylformamide, and 89 parts by weight of the terminal alcoholic polycarbonate oligomer obtained in Reference Example 1 were uniformly stirred. The mixture was heated to 100'C to perform an addition reaction to produce a urethane resin.

After heating this solution to 200°C and removing the solvent under reduced pressure in an extruder, the temperature at the cylinder temperature was 270°C.
, injection molded at a mold temperature of 100℃, diameter 12cm
A transparent disk substrate with a thickness of 1.2 mm was made. The water absorption rate of this substrate was 0.5%, which was extremely low compared to 1.2% of the acrylic resin, and the birefringence was also good. The results of the characteristics are shown in Table 3.

Example 10 91 parts by weight of the terminal alcoholic polycarbonate oligomer obtained in Reference Example 1, 9 parts by weight of xylylene diisocyanate
A disk substrate was manufactured according to Example 1 using the heavy ω portion. The water absorption rate of this substrate was 0.4%, and the birefringence was also good. The results of the characteristics are shown in Table 3.

Example 11 A disk substrate was prepared according to Example 1 using 91 parts by weight of the 1q-terminated alcoholic polycarbonate oligomer and 9 parts by weight of the water additive of kylylene diisocyanate. The water absorption rate of this substrate was 0.4%, which was comparable to polycarbonate, and the birefringence was also good. The results of the characteristics are shown in Table 3.

Comparative Example 5 Injection molded using polymethyl methacrylate, diameter 1
A disk substrate of 2 cm and 1.2 sides in thickness was obtained.

The results of the characteristics are shown in Table 3. Although it has good birefringence, it has a drawback of high water absorption.

Comparative Example 6 Injection molded using polycarbonate, diameter 12 cm,
A disk substrate with a thickness of 1.2 cm was used. The results of the characteristics are shown in Table 3. The water absorption property is excellent, but the birefringence is poor.

[Effects of the invention] The urethane resin of the invention can be used as an optical molding material,
In particular, when used in optical disk substrates, it is possible to produce optical disk substrates that have excellent dimensional stability, excellent birefringence, and toughness due to their excellent water absorption.

Claims (1)

[Claims] (1) A resin for optical substrates comprising a polymer having a urethane unit structure represented by the following general formula [I] as a repeating unit. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, A and B have the following structures. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the A component, R is carbon Among them, 1 to 3 divalent aliphatic, alicyclic or sulfone, X is a lower alkyl group of C_1 to_1_5, Cl or Br, n = an integer of 5 to 300, m =
An integer of 0 to 2, p and q represent integers of 0 to 2, U is a divalent aliphatic, alicyclic, or phenyl-substituted alkyl group of C_1 to_1_5, and Y is a simple bond or -COO- , S represents an integer of 1 to 20, and T represents an integer of 5 to 10. ) B: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ One or more organic groups selected from. ]