JPH0782377A - Sulfonated aromatic polysulfone - Google Patents

Abstract

(57) [Summary] [Object] To provide a high refractive index material having a high refractive index exceeding 1.70 and being suitable for use in optical lenses, antireflection films and the like. A sulfonated aromatic polysulfone, characterized in that at least one hydrogen atom on the aromatic ring of an aromatic polysulfone having a repeating unit represented by the following formula (I) is substituted with a —SO ₂ OH group. . [Chemical 1]

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sulfonated aromatic polysulfone which has a high refractive index and can be suitably used for optical lenses, antireflection films and the like.

[0002]

2. Description of the Related Art Plastic optical materials are lighter in weight, harder to crack, and easier to process than inorganic materials.
It is rapidly becoming popular as an optical element such as an eyeglass lens and a camera lens.

Resins widely used for these purposes are those obtained by radically polymerizing diethylene glycol bisallyl carbonate. This resin has various characteristics such as excellent impact resistance, light weight, excellent dyeability, and good processability such as machinability and abrasiveness. There is. However, the refractive index of this resin is (n _D
= 1.52), n _D = 1.50, which is small. Therefore, in order to obtain the optical properties equivalent to those of the glass lens, it is necessary to increase the center thickness, the edge thickness and the curvature of the lens, which has a drawback that the overall thickness is inevitable. .

For use as an optical multilayer film (selective reflection film, selective transmission film, etc.), a higher refractive index (n _D ≧
1.70) is required, but there are few plastic materials having such a high refractive index, and even a high refractive index material has problems of transparency and coloring, which is not suitable for practical use. Had a point.

The currently used optical multilayer films are formed by vapor-depositing an inorganic material. However, it is difficult to vapor-deposit a large area and the cost is high. Has not yet been used. Therefore, there has been an increasing demand for a plastic high-refractive material capable of forming a coating film by a simple coating method.

Japanese Unexamined Patent Publication (Kokai) No. 62-47601 discloses an antireflection film composed of three thin films having different refractive indexes formed by a coating method. Here, each layer is formed from a colloidal dispersion of antimony oxide particles.
However, this antireflection film has a problem of poor transparency.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems.
It is an object of the present invention to provide a sulfonated aromatic polysulfone having a high refractive index of more than 1.70 and being suitable for use in optical lenses, antireflection films and the like.

[0008]

The inventors of the present invention have conducted extensive studies in order to solve the above problems, and as a result, a material obtained by partially sulfonation of an aromatic polysulfone having a specific structure showed 1.70. The inventors have found that a high refractive index exceeding the above is provided and completed the present invention.

The sulfonated aromatic polysulfone of the present invention has at least one hydrogen atom on the aromatic ring of the aromatic polysulfone having a repeating unit represented by the following formula (I) substituted with a --SO ₂ OH group. It is characterized by

[0010]

[Chemical 2]

The present invention will be described in detail below.

The aromatic polysulfone used in the present invention has a repeating unit represented by the above formula (I).

Examples of the monomer capable of forming the repeating unit represented by the above formula (I) include 4-chloro-4'-
(P-hydroxyphenyl) diphenyl sulfone, 4-
Chloro-4 ′-(p-chlorophenyl) diphenyl sulfone, 4-hydroxy-4 ′-(p-hydroxyphenyl) diphenyl sulfone, 4-bromo-4 ′-(p-hydroxyphenyl) diphenyl sulfone, 4-iodo-
4 '-(p-hydroxyphenyl) diphenyl sulfone and the like can be mentioned. Of these, 4-chloro-4 ′-(p-hydroxyphenyl) diphenyl sulfone is preferable because of its ease of synthesis and availability.

The aromatic polysulfone may be copolymerized with a copolymerizable aromatic monomer in an amount of less than 30 mol%. Such aromatic monomers include 4,4'-dihydroxydiphenyl sulfone, bisphenol A, bisphenol F, p-hydroxyphenol, 4,4'-
Dihydroxybiphenyl, 4,4 '''-dihydroxy-p-quaterphenyl,4,4'-dihydroxydiphenyl ether, diol such as 4,4'-dihydroxydiphenyl ketone, 4,4'-dichlorodiphenyl sulfone, 4,4 Examples include dihalides such as'-dichlorodiphenyl ketone. Among them, 4,4 '''-
When dihydroxy-p-quaterphenyl is used as a comonomer, it is preferable because it has the effect of improving the refractive index of the obtained sulfonated aromatic polysulfone, but when the content of the comonomer is 30 mol% or more. However, since it exhibits crystallinity and impairs transparency, it cannot be used as an optical material. Of the above, 4,4'-dichlorodiphenyl sulfone is easily available,
When it is copolymerized at a ratio of less than 30 mol%, the refractive index is increased, which is preferable, but when copolymerized at a ratio of 30 mol% or more, the refractive index of the sulfonated aromatic polysulfone obtained is decreased. To do.

A preferred method for producing the aromatic polysulfone used in the present invention is a monomer having a hydroxyl group and a monomer having a halogen group (at least one of them) in a polar solvent in the presence of an alkali metal or a metal salt. Has a sulfonyl group) is used, for example, a method of polymerizing these monomers in an aprotic polar solvent in the presence of an alkali metal carbonate. The alkali metal carbonate is capable of forming an alkali metal salt by reacting with a monomer for forming the repeating unit represented by the formula (I) or a monomer having a hydroxyl group among the copolymerizable monomers. So, specifically, sodium carbonate, potassium carbonate,
Examples thereof include rubidium carbonate and cesium carbonate.

In the polymerization, the monomer capable of forming the repeating unit of the formula (I), the above-mentioned monomer having a hydroxyl group and the monomer having a halogen group are mixed in such a manner that the total amount of halogen of the monomer is different from that of the monomer. It is preferable to carry out in the range such that the group becomes 90 to 110 mol%. In order to obtain a higher polymer, it is preferably used within the range of 95 to 105 mol%.

Examples of the aprotic polar solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and 1,3-
Examples thereof include amide solvents such as dimethyl-2-imidazolidinone and dimethylimidazoline, and sulfone solvents such as dimethyl sulfoxide, sulfolane and diphenyl sulfone. If necessary, an azeotropic dehydration solvent such as benzene, toluene, xylene, chlorobenzene, monochloroethane, dichloroethane, trichloroethane, tetrachloroethane, monochloroethylene, dichloroethylene, trichloroethylene and the like can be added.

In the production of the aromatic polysulfone, the polymerization reaction temperature is usually in the range of 80 to 400 ° C., though it varies depending on the reaction raw materials, the types of components, the type of polymerization reaction, etc.
It is preferably carried out in the range of 100 to 350 ° C. When the reaction temperature is lower than the above temperature range, the intended polymerization reaction does not proceed at a speed that can be practically used, and it is difficult to obtain a polymer having a required molecular weight. On the other hand, when the reaction temperature is higher than the above range, side reactions other than the intended polymerization reaction cannot be ignored, and the resulting polymer is significantly colored. The time required for the polymerization reaction varies depending on the type of reaction raw material components, the type of polymerization reaction, etc., but is usually 10 minutes to 1 minute.
The time is in the range of 00 hours, preferably 1 hour to 24 hours.

In the production of the aromatic polysulfone, it is preferable that oxygen is not present as an atmosphere for carrying out the reaction, and if the reaction is carried out in nitrogen or other inert gas, good results can be obtained. This is because the alkali metal salt that has reacted with the hydroxyl group is easily oxidized when heated in the presence of oxygen, which hinders the intended polymerization reaction and makes it difficult to increase the molecular weight, and also causes coloring of the produced polymer. Because.

In the production of the aromatic polysulfone, the reaction mixture is usually cooled to stop the polymerization reaction. Further, in order to stabilize the phenoxide group which may be present at the terminal of the polymer and stop the polymerization reaction, addition reaction of an aliphatic halide, an aromatic halide or the like is carried out as necessary. . Specific examples of the above halides include methyl chloride, ethyl chloride, methyl bromide, 4-chlorodiphenyl sulfone, 4-chlorobenzophenone, 4,
4'-dichlorophenyl sulfone, 4-chloronitrobenzene, etc. can be mentioned.

The molecular weight of the above-mentioned aromatic polysulfone can be expressed by using the reduced viscosity as a guide, and the reduced viscosity is 0.35 dl / g to 0.10 when measured at a concentration of 1 g / dl in dimethylformamide at 30 ° C. It is preferably 6 dl / g. When the reduced viscosity is less than 0.35 dl / g, the mechanical strength of the molded product obtained by using the obtained polymer is not sufficient, and when it exceeds 0.6 dl / g, the moldability as a lens material and the optical multilayer film are improved. Is not preferable because the coating film forming property of is reduced.

The method of substituting hydrogen atoms on the aromatic ring of aromatic polysulfone with --SO ₂ OH groups (hereinafter referred to as sulfonation method) is a method in which aromatic polysulfone obtained by the above method is concentrated in sulfuric acid (concentration: 95%). The above is achieved by dissolving in. The degree of sulfonation can be controlled by the holding time in a state of being a sulfuric acid solution, and the solution sulfonated for a predetermined time is then put into a poor solvent of sulfonated aromatic polysulfone such as water or alcohol. , The polymer can be precipitated. At this time, it is possible to accelerate the sulfonation by heating the solution. Also, the degree of sulfonation is preferably less than 5% of the hydrogen atoms on the aromatic ring. When the degree of sulfonation is 5% or more of the hydrogen atoms on the aromatic ring, the resulting polymer becomes water-soluble and is not preferable because it is limited in use as an optical material. A particularly preferable degree of sulfonation is 0.5 to 4.5%.

As a method for obtaining a molded article using the sulfonated aromatic polysulfone of the present invention, for example, the sulfonated aromatic polysulfone is dissolved in a solvent such as dimethylformamide and the solution is cast into a film or the like by a casting method. There is a method. The molded product thus obtained can be used for various optical materials, particularly optical lenses and optical multilayer films, as a material having a high refractive index of 1.70 or more, and has great industrial utility value.

[0024]

EXAMPLES The present invention will be described in more detail based on the following examples.

(Example 1) 4-chloro-4 '-(p-hydroxyphenyl) was placed in a polymerization reaction vessel equipped with a stirrer, a gas introduction tube, a thermometer and a condenser having a receiver at its tip.
100 parts by weight (100 mol%) of diphenyl sulfone, 22.8 parts by weight of anhydrous potassium carbonate, and 100 parts by weight of diphenyl sulfone were charged, and nitrogen substitution was carried out. Then, stirring and temperature increase were started under a nitrogen atmosphere to increase the system temperature to 26
The reaction was carried out by holding at 0 ° C for 3 hours. After completion of the reaction, the reaction solution was cooled to 50 ° C., 100 ml of dimethylformamide was poured into the solidified sample, and the dissolved sample was poured into an acetone-methanol mixed solvent to precipitate a polymer powder. By further washing with water to remove potassium chloride,
After drying at 120 ° C. for 24 hours in a vacuum dryer, a white polymer was obtained. The polymer obtained had a reduced viscosity of 0.40 dl
/ G (30 ° C., 1 g / dl in dimethylformamide).

This polymer was dissolved in concentrated sulfuric acid (95%) to prepare a 5% by weight solution. After standing for 24 hours, this solution was put under stirring of water to precipitate a white fine powder of sulfonated aromatic polysulfone. The obtained powder is
After repeated washing with water, it was dried at 120 ° C. When the sulfur atom content was measured by elemental analysis, it was 12.7% by weight, and it was found that 2.8% of the hydrogen atoms on the aromatic ring were replaced by —SO ₂ OH groups. This sulfonated aromatic polysulfone was dissolved in dimethylformamide to give 1
A 0 wt% solution was prepared, and a film was formed from this solution by a casting method. As a result, a colorless transparent film was obtained.
When the refractive index of this film was measured with an Abbe refractometer at 25 ° C., n _D = 1.73.

Example 2 The procedure of Example 1 was repeated, except that the aromatic polysulfone polymer polymerized in Example 1 was dissolved in concentrated sulfuric acid, allowed to stand for 48 hours, and then poured into water. When the sulfur atom content rate was measured by elemental analysis, it was 13.7% by weight, which was 4.2% of the hydrogen atoms on the aromatic ring.
% Was found to be replaced by -SO ₂ OH group.
When the refractive index was measured in the same manner as in Example 1, n _D =
It was 1.76.

(Example 3) 4-chloro-4 '-(p-hydroxyphenyl) diphenylsulfone 100 parts by weight (60 mol%), 4,4 "'-dihydroxy-p-quarterphenyl 32.8 parts by weight (20 mol%), 4,
27.9 parts by weight of 4'-dichlorodiphenyl sulfone (2
0 mol%), anhydrous potassium carbonate 33.0 parts by weight, and sulfolane 290 parts by weight were polymerized in the same manner as in Example 1 to obtain an aromatic polysulfone. The reduced viscosity of the obtained polymer was 0.40 dl / g (30 ° C., 1 g / dl in dimethylformamide). Further, it was sulfonated in the same manner as in Example 1 to obtain a sulfonated aromatic polysulfone.
As a result of elemental analysis, 10.3% by weight of sulfur atoms were contained, and 1.7% of hydrogen atoms on the aromatic ring contained -SO ₂ OH.
It was found that the group was substituted. When a film was prepared in the same manner as in Example 1, a colorless transparent film was obtained. Further, when the refractive index was measured by the same method as in Example 1, n _D = 1.75.

(Examples 4 and 5) 4-chloro-4'-
(P-hydroxyphenyl) diphenyl sulfone, 4,
The amounts of 4 ′ ″-dihydroxy-p-quaterphenyl and 4,4′-dichlorodiphenyl sulfone are shown in Table 1.
Aromatic polysulfone was obtained by polymerizing in the same manner as in Example 1 except that the components were blended as shown in FIG. Further, it was sulfonated in the same manner as in Example 1 to obtain a sulfonated aromatic polysulfone. Elemental analysis was performed in the same manner as in Example 1. Further, a film was prepared in the same manner as in Example 1 and the refractive index was measured. The results obtained are shown in Table 1 below.

Example 6 The aromatic polysulfone prepared in Example 1 was retained as a concentrated sulfuric acid solution for 100 hours for sulfonation. The resulting polymer was water soluble.
Therefore, the polymer was deposited by pouring it into ethanol and solidifying it. The sulfonation rate of the obtained polymer was 6.0%. The results obtained are shown in Table 1 below.

Comparative Example 1 A film was prepared without sulfonation of the aromatic polysulfone obtained in Example 1, and the sulfonation rate and the refractive index were measured in the same manner as in Example 1. The results obtained are shown in Table 1 below.

Comparative Example 2 To 100 parts by weight of diethylene glycol bisallyl carbonate, 3 parts by weight of diisopropyl peroxydicarbonate was added, and 50 × 50 × 1 was added.
Pour into a 05mm mold and 40 ° C under nitrogen atmosphere.
In an oven for 24 hours. Then, at 80 ℃ 4
The temperature was kept at 120 ° C. for 2 hours to complete the curing. The results obtained are shown in Table 1 below.

The compositional ratios of the aromatic polysulfones used in Examples 1 to 6 and Comparative Examples 1 to 2, and the measurement results of the reduced viscosity, sulfonation rate and refractive index are shown in Table 1 below.

[0034]

[Table 1]

[0035]

According to the present invention, it is possible to provide a high refractive index material having a high refractive index exceeding 1.70 and being suitable for use in optical lenses, antireflection films and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Nakayama 2-2 Hyakusan, Shimamoto-cho, Mishima-gun, Osaka Prefecture (2-2) Inventor Tonosuke Saito 5-17-21 Yamatedai, Ibaraki-shi (72) Hiroki Kakumachi 1-11-3 Minami Kasugaoka, Ibaraki City (72) Inventor Daishiro Kishimoto 2-24-23 Mishimaoka, Ibaraki City Sun Heights Mishimaoka 306

Claims (1)

[Claims] 1. A sulfonated aroma wherein at least one hydrogen atom on an aromatic ring of an aromatic polysulfone having a repeating unit represented by the following formula (I) is substituted with a —SO ₂ OH group. Group polysulfones. [Chemical 1]