JPH03215523A - Material for optical instrument - Google Patents

Abstract

PURPOSE:To improve the optical characteristics, heat resistance, moisture resistance, impact strength, moldability, etc., by reacting a specific dihydric phenol, a carbonic ester-forming compd., and a carboxylated polyfunctional org. compd. CONSTITUTION:A dihydric phenol of formula I (wherein X is a group selected from formulas II to V; and R<1> and R<2> are each H or 1-6C alkyl) (e.g. bisphenol A) is reacted with a carbonic ester-forming compd. (e.g. phosgene) in the presence of an acid acceptor in a solvent at 10-50 deg.C to give an oligomer having a degree of polymn. of 1-10 and reactive chloroformate groups at its terminals. Then, the oligomer is reacted with a polyfunctional, at least trifunctional, org. compd. having a carboxyl group or a group which, on hydrolysis, forms a carboxyl group, the dihydric phenol, and the carbonic ester-forming compd. at 10-50 deg.C for 0.1-2hr, giving the title material comprising a branched polycarbonate resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a material for optical equipment, and more specifically, the present invention relates to a material for optical equipment, and more specifically, a material that has excellent optical properties such as small optical distortion and extremely low birefringence, and is heat resistant. Polycarbonate has excellent moisture resistance, impact resistance, moldability (fluidity during melt molding, etc.), and can be suitably used as a material for optical materials such as optical disk substrates, optical fibers, and optical lenses. Concerning resin-based materials for optical equipment. [Prior Art] Molded products used for optical purposes, such as optical disks, optical fibers, and elements for optical devices such as optical lenses, must be transparent and have small optical distortion. In particular, in optical discs that use digital signals, optical distortion is required to be a phase difference of 20 nm or less in molded products. In addition, in order to focus the light beam onto the recording film of the substrate, the light beam enters and travels obliquely to the substrate, and this obliquely incident light exhibits a large phase difference.
This may cause errors when writing or reading information.

Polycarbonate resins, acrylic resins (such as PMMA), polystyrene resins, and the like are used as polymer optical materials for conventional optical discs and the like.

However, among these, acrylic resins such as PMMA have excellent optical properties, but they have problems with heat resistance, moisture resistance, impact resistance, etc., and also cause twisting and dimensional stability during molding. There is a problem that it is bad. On the other hand, although polycarbonate resin covers the drawbacks of acrylic resins such as PMMA mentioned above, conventional polycarbonate resin has large optical distortion, which increases birefringence and reduces reading sensitivity. There are problems such as deterioration and the tendency for errors to occur. Therefore, a method has been proposed in which the optical distortion is attempted to be improved by polymerizing using trisphenols as a branching agent during the production of polycarbonate (for example, Japanese Patent Application Laid-Open No. 60-215019 ). However, in this method, the type of branching agent used is not appropriate, and if the amount of branching agent used is small, the improvement effect on optical distortion is small. When the amount used is increased, there is a problem that properties such as strength and heat resistance of the resin decrease as the amount used increases. [Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances. The object of the present invention is to have sufficiently small optical distortion of a molded product.
Polycarbonate with a specific structure that has excellent optical properties such as extremely low birefringence, as well as excellent heat resistance, moisture resistance, impact resistance, moldability (flowability during T8 melt molding, etc.) The purpose of the present invention is to provide a material for optical equipment made of nate resin.

[Means to solve the problem]

As a result of intensive research to solve the above problems, the present inventors have discovered that polyhydric polyphenols having a specific reactive group can be used as branching agents in the polymerization of specific dihydric phenols and carbonate ester-forming compounds such as phosgene. The present inventors have discovered that a material for optical equipment made of a polycarbonate resin with a specific structure obtained using a functional organic compound satisfactorily satisfies the above objectives, and based on this knowledge, the present invention has been completed. That is, the present invention is based on the following general formula l? R represents R, and R' and Rt each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ] A branched product obtained by reacting a dihydric phenol represented by the above with a carbonate ester-forming compound and a trifunctional or higher-functional polyfunctional organic compound containing a carpoxy group or a reactive group that becomes a carboxyl group upon hydrolysis. We provide materials for optical equipment made of polycarbonate resin. In the general formula (I), "or R2 may be an alkyl group having 1 to 6 carbon atoms, but as this alkyl group,
For example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, 1-methylpropyl group, tert-butyl group, bentyl group, isopentyl group,
Examples include 1-methylbutyl group, 1-ethylpropyl group, cyclopentyl group, hexyl group, isohexyl group, 1-methylbentyl group, 1-ethylbutyl group, neohexyl group, cyclohexyl group, methylcyclopentyl group, cyclopentylmethyl group, etc. ．． In addition, the RI
and at may be a hydrogen atom. Said Rl and R! Of the above, each is preferably a hydrogen atom or a methyl group.

Note that R1 and Rt may be the same or different.

X in the general formula (1) is the above-mentioned specific group CHI f However, 101 is particularly preferred.

1 CHff Specific examples of the dihydric phenol represented by the general formula (1) include 2.2-bis(4-hydroxyphunyl)propane [i.e., bisphenol A), 2.2
-bis(3-methyl-4-hydroxyphenyl)propane [i.e. bisphenol C), 2,2-bis(3
-ethyl-4-hydroxyphenyl)propane, 2.2
-Bis(3-propyl-4-hydroxyphenyl)propane, 2.2-bis(3-butyl-4-hydroxyphenyl)propane, 2.2-bis(3-benthyl-4-hydroxyphenyl)propane, 2.2 -bis(3-hexyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)brovane, 2-(4-hydroxyphenyl)-2- (3
-methyl-4-hydroxyphenyl)propane, 1,1
-bis(4-hydroxyphenyl)-1-phenylethane, 1.1-bis(3-methyl-4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, bis(3-methyl -4-hydroxyphenyl)diphenylmethane, 1,1-bis(4
-hydroxydiphenyl)cyclohexane, 1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane, and the like.

Among these, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane , 1.1-bis(3
-Methyl-4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, bis(3-methyl-4-hydroxyphenyl)diphenylmethane, I,1-bis(4-hydroxyphenyl)cyclohexane , 1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane, etc. are preferable, particularly 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl), and the like. Phenyl)broban and the like are preferred.

In addition, when manufacturing (synthesizing) the branched polycarbonate resin used in the material for optical equipment of the present invention, the dihydric phenol represented by the general formula (1) may be used alone. However, two or more types may be used in combination, if necessary.

Examples of the carbonate ester-forming compound include those used in the production of known polycarbonates, such as carbonyl dihalides such as phosgene, haloformates such as chloroformates, and carbonate esters such as dialkyl carbonates. Among these, phosgene is particularly preferred. In addition, when manufacturing (synthesizing) the branched polycarbonate resin used in the optical equipment material of the present invention, these various carbonate ester-forming compounds may be used alone, or they may be used in combination as necessary. Two or more types may be used in combination.

The polyfunctional organic compound contains a carpoxy group or a reactive group that becomes a carboxyl group upon hydrolysis, and examples of this reactive group include, for example, a chloroformyl group (-CO
haloformyl group (monofunctional group) such as CI), -CO-
0-CO- (difunctional group, equivalent to two carboxy groups)
etc. can be mentioned. Among these, chloroformyl group is particularly preferred. Further, the polyfunctional organic compound is a trifunctional or higher polyfunctional organic compound. Note that this polyfunctional organic compound having trifunctionality or more is for branching the polycarbonate molecule, and is therefore made to have trifunctionality or more. Therefore, the term ``trifunctional or higher'' as used herein means ``three or more reactive functional groups (however,
Difunctional groups are counted as two. The same applies hereafter).

One important point here is that at least one, preferably three or more, of the reactive functional groups in the trifunctional or higher polyfunctional organic compound become the carboxylic group or a carboxy group upon hydrolysis. The point is that it is a reactive group. That is, the material for optical equipment of the present invention has the above-mentioned specific reactive functional group (carboxy group or chloroformyl group, -co-o
Branched polycarbonate 1- obtained by using a polyfunctional organic compound having the above-mentioned reactive groups such as -co group, particularly preferably chloroformyl group, as a branching agent.
It should be noted that it is made of resin.

Incidentally, when using only other trifunctional or higher polyfunctional compounds (such as trisphenol) having only a phenolic hydroxyl group, which is another reactive functional group, as a branching agent, the above-mentioned A problem arises. As the polyfunctional organic compound which is a branching agent having such a specific reactive functional group, various compounds such as aromatic compounds, aliphatic compounds, and alicyclic compounds can be used. However, among others, the specific reactive functional group is 3
Those directly bonded to at least one aromatic ring such as a benzene ring are preferred.

Specific examples of this preferred aromatic polyfunctional organic compound include 1,2,4-benzenetricarboxylic acid [
That is, trimellitic acid], trimellitic anhydride, 1
, 3.5-benzenetricarboxylic acid [i.e. trimesitic acid], 1,2.4,5-benzenetetracarboxylic acid [i.e. pyromellitic acid], biromellitic anhydride, ■. 2,4-tri(chloroformyl)benzene [i.e., trimellitic acid trichloride], 1,3,5-tri(chloroformyl)benzene [i.e., trimellitic acid trichloride], 1,2,4,5-tetra(chloro formyl)benzene [i.e., biromellitic acid tetrachloride L 3.5.3'5'-tetra(chloroformyl)bih7enyl, 3,4.3',5'-tetra(chloroformyl)biphenyl, etc. Can be done.
Among these, trimesitic acid trichloride and the like are particularly preferred.

In addition, when producing (synthesizing) the branched polycarbonate resin used in the material for optical equipment of the present invention, the various polyfunctional organic compounds used as branching agents include:
One type may be used alone, or two or more types may be used in combination, if necessary.

The branched polycarbonate resin used in the optical equipment material of the present invention is obtained by reacting the dihydric phenol represented by the general formula (1) with a carbonate-forming compound such as phosgene and the polyfunctional organic compound. This can be obtained by

The average molecular weight of the branched polycarbonate resin used may be appropriately selected depending on the purpose, but generally the viscosity average molecular weight (M,) is usually 12.00.
Those in the range of 0 to 20,000, especially 14,
Those within the range of 000 to 17.000 are preferably used.

If this viscosity average molecular weight is too low, the molded product will become brittle, while if it is too high, it will be difficult to mold or the resin will not have sufficient fluidity during melt molding, resulting in a molded product with optical properties. This may result in non-uniformity and increased birefringence. When producing (synthesizing) the branched polycarbonate resin, the proportion of the polyfunctional organic compound used as a branching compound is usually 0.000 to the dihydric phenol used. A suitable range is about 1-10 mol%, preferably 1-5 mol%. If this proportion is less than 0.1 mol%, the degree of branching of the obtained resin will be insufficient, and a sufficient effect of improving optical properties may not be obtained. On the other hand, if this proportion is too large, undesirable polymers may be produced. or the strength of the resin may decrease.

In addition, when manufacturing (synthesizing) the branched polycarbonate resin used in the optical equipment material of the present invention, other dihydric phenols other than those mentioned above may be added as necessary to the extent that does not impede the purpose of the present invention. Various components such as a polymer component or a branching agent other than the above-mentioned specific polyfunctional organic compound can also be used in combination as appropriate. The branched polycarbonate resin used in the material for the optical device 2S of the present invention contains -
There is no particular restriction on the manufacturing method as long as it can be obtained by reacting a carbonate ester-forming compound with the above-mentioned specific branching agent (polyfunctional organic compound), and any known manufacturing method of polycarbonate may be used. It can be produced by various methods such as the polymerization method used.

When producing this branched polycarbonate resin,
Examples of methods that can be particularly suitably employed include the following methods.

Example of a method for producing a branched polycarbonate resin A bihydric phenol component represented by the general formula (+) such as bisphenol A1 and bisphenol C is mixed with phosgene or the like in the presence of an acid acceptor and a suitable solvent with sufficient stirring. The oligomer is reacted with the carbonate ester-forming compound to obtain an oligomer having a chloroformate reactive group at the end. At this time, a gaseous carbonate-forming compound such as phosgene is usually supplied while being blown into the reaction system.

As the acid acceptor to be used, various inorganic or organic alkali compounds used in ordinary polycarbonate polymerization can be used, but usually, for example, sodium hydroxide, potassium hydroxide, etc. are preferable. It can be used for. Note that these can be added as a solution such as an aqueous solution.

As the solvent, a solvent commonly used for polymerization of polycarbonate can be used, and specifically, for example, a halogenated hydrocarbon solvent such as methylene chloride is preferably used.

The ratio of the acid acceptor used is 1:1 of the dihydric phenol used.
per equivalent (1 mole corresponds to 2 equivalents), usually 1
equivalent or more, preferably 1.2 to 3. It is appropriate that the amount be within the range of Q equivalent.

The reaction temperature at this time is usually about 10 to 50°C, preferably about 20 to 40°C.

At this point, the degree of polymerization of the obtained oligomer is
Generally, it is desirable to select reaction conditions such as reaction time so that the reaction time is within a range of about 1 to 10, preferably about 1 to 5.

Next, the aqueous layer is removed from the reaction mixture to obtain an organic layer containing the oligomer, to which a predetermined amount of the polyfunctional organic compound such as trimesinate trichloride and an appropriate amount of a suitable terminal capping agent are added. Add a suitable solvent if necessary and add the given dihydric phenol (e.g. the same one used above) and the given acid acceptor (e.g. the same one used above) again under stirring. A predetermined amount of a mixture of (usually the same proportions as above) is added, and the reaction is completed in the presence of a suitable catalyst.

As the terminal capping agent to be used, terminal capping agents used in ordinary polycarbonate polymerization can be used, and specifically, for example, p-te, monohydric phenols such as L-butylphenol, etc. can be mentioned.

As the catalyst to be used, catalysts commonly used for polymerization of polycarbonate can be used, and specifically, for example, amines such as triethylamine are preferably used.The reaction temperature in this case is The temperature is usually about 10 to 50°C, preferably about 20 to 40''C.

It is usually sufficient for the reaction time to be about 0.1 to 2 hours.

The branched polycarbonate resin can be suitably synthesized as described above.

Post-treatment after completion of the reaction can be carried out according to conventional methods. For example, from the reaction mixture obtained above, the aqueous layer is separated and removed to obtain an organic layer containing the desired polymer,
This is washed appropriately in the order of, for example, alkali, acid, and water.
After removing impurities such as salts and catalysts, the polymer may be separated and recovered by reprecipitation using a poor solvent such as methanol. In this way, desired branched polycarbonate resins can be obtained as various homopolymers or copolymers of desired purity, or as mixtures thereof. In the manner described above, the branched polycarbonate resin used in the material for optical equipment of the present invention can be efficiently produced in a simple process.

The material for optical equipment of the present invention can be obtained by molding the branched polycarbonate resin produced by various methods, including the branched polycarbonate resin obtained as described above, into a desired shape.

Various molding methods can be used depending on the purpose; for example, in the case of optical disc substrates, melt injection molding is usually preferably used.

The molding temperature (melting temperature of the resin) at that time is usually 240
It is appropriate to set the temperature in the range of about 340°C to 340°C, preferably about 280 to 320°C. If this molding temperature is too low, the resin or resin composition will not be sufficiently melted, resulting in decreased fluidity and, as a result, optical distortion may occur in the molded product. Filling of the mold etc. may be incomplete, which may cause problems with transferability. On the other hand, if the temperature is too high, the resin may decompose, resulting in coloring or silver formation. The mold temperature is usually in the range of about 60 to 140°C, preferably about 80 to 120°C.

If this temperature is too low, birefringence is likely to occur due to residual stress in the molded product. On the other hand, if it is too high,
Molded products may be deformed. In addition, the material for optical equipment of the present invention comprises the various branched polycarbonate resins described above,
Usually, it is sufficient to use one type alone, but if necessary, two or more types can be used in combination as a polymer blend. In addition, when manufacturing and molding the material for optical equipment of the present invention, the branched polycarbonate resin may be added with, for example, ultraviolet absorbers, antioxidants, heat treatment, etc., as necessary, to the extent that does not impede the purpose of the present invention. Various additives such as a stabilizer, a weather resistance improving agent, an antistatic agent, an antifogging agent, a mold release agent, a plasticizer, and other polymer components can also be included as appropriate depending on the purpose of use.

The material for optical equipment of the present invention has excellent optical properties such as small optical distortion and extremely low birefringence, and is also heat resistant, moisture resistant, impact resistant, and moldable (flowability during melt molding, etc.) Because of its excellent properties, it can be suitably used as a raw material for various optical materials such as optical disk substrates, optical fibers, and optical lenses. [Examples] The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited thereto. In addition, in the following Examples and Comparative Examples, the physical properties of each resin and molded product sample thereof were evaluated as follows. (Evaluation method) Glass transition temperature (T.): Measured by DSC according to a conventional method.

Viscosity average molecular weight (Mv): 0. The value measured at 20°C for a solution with a concentration of 5 g/a was calculated in terms of polycarbonate made from bisphenol A as a raw material. Birefringence: Each resin was molded to a thickness of 1.2 am, 3. 5 X 3. It was molded into a 5 m square flat plate, and the molded product sample was measured using a polarizing microscope equipped with a Perec type compensator.

Photoelastic constant (C.) when melted: Each resin is melt-spun and wound using a cavilograph manufactured by Toyo Seiki Co., Ltd. At that time, the stress applied to the thread is plotted on the horizontal axis, and the birefringence of the thread is plotted on the vertical axis. The slope of the straight line taken was taken as the photoelastic constant (C.) during melting.

This C. The smaller the value, the better the optical properties.

These evaluation results were mainly used as indicators of the physical properties of the resin and the optical properties of the molded product sample as a material for optical equipment.

Examples 1-4 228 g of bisphenol A (i.e., 2,2-bis(4-hydroxydiphenyl)propane) was dissolved in 1.5N of N
After dissolving in 1.52 kg of a O 2 H aqueous solution and adding 650 d of methylene chloride to this solution, phosgene gas was blown in at a feed rate of 1,300 d/min while stirring vigorously at 15°C. When the pH of the reaction system reached 10, the supply of phosgene was stopped and the organic layer was separated by standing. This organic layer contains
It was confirmed that an oligomer having a terminal chloroformate group with a degree of polymerization of about 1 to 5 existed.

Next, the following operations were performed under the respective reaction conditions shown in Table 1 to produce four types of branched polycarbonate resins.

That is, p-tert-butylphenol (PTBP) was added to the oligomer 300d obtained above as a terminal stopper.
, trimesitic acid trichloride [i.e., 1,3.5-tri(chloroformyl)benzene] as a branching agent.
and methylene chloride from 150 companies, and while stirring vigorously at 25°C, bisphenol A was added as a monomer.
N dissolved in an aqueous solution of NaO and triethylamine (0.5 + * mol/1 aqueous solution) 1- as a catalyst were added.

Shortly thereafter, an exotherm occurred and the reaction began. After reacting for 60 minutes, the organic layer was separated, washed in this order with alkali, acid, and water, and the polymer was precipitated with methanol and collected. It was confirmed by IR analysis etc. that the polymers thus obtained were all branched polycarbonate resins having repeating units represented by the following formula and branched structural units represented by the following formula. The proportion of the branched structural unit in the polymer obtained in Example 1 was approximately 1 mol%. Molded samples were prepared from each of the resins thus obtained using the evaluation method described above, and their physical properties were evaluated according to the methods described above. The results are shown in Table 2. Examples 5 to 8 Polymers were prepared in the same manner as in Examples 1 to 4, except that bisphenol C [i.e., 2,2-bis(3-methyl-4-hydroxyphenyl)propane] was used in place of bisphenol A. was manufactured.

It was confirmed that each of the polymers thus obtained was a branched polycarbonate resin having a repeating unit represented by the following formula and the branched structural unit (similar to Examples 1 to 4). .

For each of the resins thus obtained, the physical properties of the resin and molded sample thereof were measured in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 Each physical property was measured in the same manner as in Example 1 for a commercially available polycarbonate resin (polycarbonate made from linear bisphenol A; key points of manufacturing conditions are shown in Table 3). The results are shown in Table 2.

Comparative Example 2 In Example 3, instead of trimesitic acid chloride,
α, α′. α“monotris(4-hydroxyphenyl)-
1.3.5-} It was carried out in the same manner except that lyisopropyrhenzene (trisphenol) was used and the conditions shown in Table 3 were used.

The results are shown in Table 2.

Comparative Example 3 In Example 7, instead of trimesitic acid chloride,
α. α′. α-tris(4-hydroxyphenyl)-
1.3.5-1-lyisobrobylbenzene (trisphenol) was used and the same procedure was performed except that the conditions shown in Table 3 were used. The results are shown in Table 2. Table 1 Heptanomer to be reacted with 0 oligomer Table 2 [Effects of the invention] According to the present invention, a specific bisphenol has a common carbonate-forming compound and a specific reactive functional group as a branching agent. Since we use a branched polycarbonate resin with a specific structure that can be obtained by reacting with a specific polyfunctional compound, the optical distortion of the molded product is sufficiently small and birefringence is extremely low. It has excellent optical properties, as well as heat resistance, moisture resistance, impact resistance, etc., and also has manufacturing advantages such as easy molding because the resin has excellent fluidity during melt molding. It is possible to provide materials for optical instruments that are extremely useful in practice.

Claims (1)

[Claims] 1. The following general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, X in formula (I) is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formula ,Chemical formula,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ where R^1 and R^2 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ] A branched product obtained by reacting a dihydric phenol represented by the above with a carbonate ester-forming compound and a trifunctional or higher-functional polyfunctional organic compound containing a carboxy group or a reactive group that becomes a carboxyl group upon hydrolysis. A material for optical equipment made of polycarbonate resin.