JPH03217407A - Preparation of high refractive index resin - Google Patents

Abstract

PURPOSE:To prepare a colorless high refractive index resin having a high light permeability and useful for preparing optical lenses, etc., by mixing a compound containing a specific sulfur-containing acrylic monomer as a main component with a photopolymerization initiator, radically polymerizing the mixture with the irradiation of UV rays and subsequently heating the polymer at a specific temperature. CONSTITUTION:A compound comprising mainly a sulfur-containing acrylic monomer [e.g. p-bis(beta-acryloyloxyethylthio)xylene]of the formula (R<1>, R<2> are H, methyl; Ar is 6-30C arylene, etc.; X is-O-, etc.; Y is -S-, etc.; m and n are 1-5; p is 0-10) and a photopolymerization initiator (preferably benzophenone, etc.,) are mixed with each other preferably in a ratio of 100 pts.wt.: 0.01-5 pts.wt. and radically polymerized by the irradiation of UV rays to prepare a colored polymer, which is heated at 80-15 deg.C, preferably 100-130 deg.C, to provide a high refractive index resin having excellent optical uniformity, heat resistance, etc.

Description

[Detailed description of the invention] [Background of the invention] Concerning a method for producing resin.

Prior Art Techniques Techniques related to resins that provide high refractive index plastic lenses have been disclosed. Among them, acrylic compounds typified by diacrylate or dimethacrylate compounds are known to be easily radically polymerized and provide lenses with excellent transparency. For example, bromine-containing bisphenol skeletons (JP-A-59-184210, JP-A-59-193915, etc.) and sulfur-containing aromatic skeletons (JP-A-60-2601-0, JP-A-61)
-123614, JP-A No. 61-254612, JP-A No. 62-195357, etc.) It has been revealed that the lenses obtained from JP-A No. 61-254612, JP-A No. 62-195357, etc.) exhibit excellent balanced optical properties with a high refractive index and a high Appe number. ing. In particular, the latter acrylic compounds with a sulfur-containing aromatic skeleton have excellent optical properties, are low-viscosity liquid compounds, and have low density polymers, making them extremely convenient for producing lightweight lenses. It is something.

Methods of radically polymerizing these acrylic compounds to form a polymer include a method of blending an organic peroxide such as penzoyl peroxide, then injecting it into a mold and heating it;
Or, after blending a photoinitiator such as penzophenone, it is poured into a mold made of a transparent base material such as glass,
A method of irradiating with ultraviolet light is known. The hue of lens resin is an extremely important quality, and it is especially important to avoid coloring it as much as possible during polymerization molding, which involves heating and irradiating ultraviolet rays.

It has been known for a long time that the method of obtaining lens resin using ultraviolet rays has an extremely high polymerization rate, is expected to have high productivity, and is an economical method. However, in applications such as lenses where extreme tinting is discouraged,
There are many practical problems.

It has been found that when attempting to obtain a polymer by blending a photoinitiator into a sulfur-containing acrylic compound and irradiating it with ultraviolet light, the resulting polymer is significantly colored. As mentioned above, this phenomenon causes a very serious quality problem as a lens resin, and therefore, in this case, ultraviolet irradiation polymerization cannot be used practically.

In order to obtain a high-productivity, high-refractive-index lens resin using a sulfur-containing acrylic compound, it is necessary to eliminate the coloring that occurs during polymerization and to increase the light transmittance to an extent that can be put to practical use. is important.

[Summary of the invention]

Problems to be Solved by the Invention> The present invention solves the above problems and provides a colorless high refractive index material that has a high refractive index and also has excellent optical properties such as high light transmittance and optical uniformity. The purpose of this invention is to provide a method for producing resin.

Means for Solving the Problems> The method for producing a colorless, high refractive index resin with excellent light transmittance according to the present invention uses a compound mainly composed of a sulfur-containing acrylic monomer represented by the following formula (I); The method is characterized in that a colored polymer obtained by radical polymerization by irradiating ultraviolet rays to a mixture consisting of a prepolymerization initiator and a prepolymerization initiator is heated in a temperature range of 80 to 150°C.

(Here, R1 and R2 each represent a hydrogen atom or a methyl group, and A' represents an arylene group having 6 to 30 carbon atoms, an aralkylene group, or a group thereof substituted with a halogen atom excluding fluorine. , X indicates 101 or -S1, and Y indicates -S if X indicates 101.
- or SO2-, and when X indicates -S, S
-, S O 2-, -co-, all have 1 or more carbon atoms
12; m and n each represent an integer of 1 to 5; p is O to Shows the number 10. ) Effect of the invention> The above object is achieved. That is, the high refractive index resin according to the present invention has a high refractive index, that is, n(,≧],58, and has excellent optical properties such as high light transmittance and optical uniformity, and also has excellent heat resistance and the like. Moreover, according to the present invention, the coloring of the polymer produced during the photopolymerization process of monomers is made colorless, thereby producing an optical resin that has a high refractive index, is colorless, and has high light transmittance. can be formed.

[Specific description of the invention]

Monomer> The high refractive index resin according to the present invention is formed by polymerizing a compound mainly composed of a sulfur-containing acrylic monomer represented by the above formula [I].

The sulfur-containing acrylic compound represented by formula CI) has a structure in which acrylic acid or methacrylic acid is linked by a sulfur-containing chain.

Specific examples of the compound of formula (1) include the following. p-bis(β-acryloyloxyethylthio)xylylene, p-bis(β-methacryloyloxyethylthio)xylylene, m-bis(β-acryloyloxyethylthio)xylylene, m-bis(β-methacryloyloxyethylthio) Xylylene, α, α′
-di(β-acryloyloxyethylthio)-2.3
, 5.6-tetrac-p-xylylene, α,α di(
β-methacryloyloxyethylthio)2, 3,
5. 6-tetrac-p-xylylene, 4.4'
-di(β-acryloyloxyethoxy)diphenyl sulfide, 4.4'-di(β-methacryloyloxyethoxy)diphenyl sulfide, 4.4'-
Di(β-acryloyloxyethoxyethoxy)diphenylsulfone, 4,4'-di(β-methacryloyloxyethoxyethoxy)diphenylsulfone, 4,4'
-di(β-acryloyloxyethylthio)diphenyl sulfide, 4,4'-di(β-methacryloyloxyethylthio)diphenyl sulfide, 4,4-
Di(β-acryloyloxyethylthio)diphenylsulfone, 4,4'-di(β-methacryloyloxyethylthio)diphenylsulfone, 4,47-di(β
-methacryloyloxyethylthio)diphenyl ketone, β,β' -di(p-acryloyloxyphenylthio)diethyl ether, β,β' -di(p-methacryloyloxyphenylthio)diethyl ether, β,β
' -di(p-methacryloxyphenylthio)diethylthioether, and -[Y-
Ar]-related oligomers, etc.

0 Q Q U-u-un ■ These can be used alone or in combination of two or more.

The sulfur-containing acrylic compound of formula [1] is the sulfur-containing acrylic compound of formula [I
1) to the sulfur-containing polyol represented by the following formula [III
) can be obtained by reacting with an acylating agent shown in

0 However, in formula [■] and formula [■], 2 represents a halogen atom, a hydroxyl group or a lower alkoxy group,
The definitions of other substituents are the same as in the case of formula [I]. ) Specific examples of the sulfur-containing polyol of formula [I1] include the following.

p-bis(β-hydroxydiethylthio)xylylene, m
-bis(β-hydroxyethylthio)xylylene, α,
α'-di(β-hydroxyethylthio)-2.
3, 5. 6-tetrac-p-xylylene,
4.4'-di(β-hydroxyethoxy)diphenyl sulfide, 4.4'-di(β-hydroxyethoxyethoxy)diphenylsulfone, 4.4'-di(
β-hydroxyethylthio)diphenyl sulfide, 4
．． 4'-di(β-hydroxyethylthio)diphenylsulfone, 4.4'di(β-hydroxyethylthio)
Oligomers related to diphenyl ketone, 4,4'-di(hydroxyphenylthio)diethyl ether, β,β'-di(p-hydroxyphenylthio)diethylthioether, and -[Y-Ar]- represented by the following formula.

Specific examples of the acylating agent of formula (m) include the following. Acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, acrylic acid chloride, methacrylic acid chloride, etc.

It should be noted that monomers (which may be a mixture within the group) consisting of the sulfur-containing acrylic compound of formula CI) enjoy the advantages of the present invention to the fullest.

However, in order to adjust the optical properties and other properties of the resulting polymer, or to adjust the viscosity of the monomer, this monomer may be combined with a radically polymerizable compound as a comonomer to the extent that the purpose of the present invention is not impaired. It may be contained in a small amount (preferably 20 parts by weight or less per 100 parts by weight of the sulfur-containing acrylic compound of formula (I)). This is why the monomer in the present invention is defined as "a compound mainly composed of a sulfur-containing acrylic monomer."

Specific examples of radically polymerizable compounds include the following. (a) Monofunctional acrylic acid and methacrylic acid esters such as methyl acrylate and methyl methacrylate; phenyl] Bifunctional acrylic acid and methacrylic esters such as propane, (c) trifunctional acrylic acid and methacrylic esters such as trimethylolpropane trimethacrylate, (di) aromas such as styrene and divinylbenzene. group vinyl compounds, etc.

Polymer> The lens resin according to the present invention can be formed by polymerizing one or more monomers consisting of a sulfur-containing acrylic compound of formula CI').

Polymerization is carried out by a photopolymerization method using ultraviolet irradiation using a general photopolymerization initiator, and for example, known techniques of radical polymerization methods such as suspension polymerization, bulk polymerization method, and emulsion polymerization method can be used. can.

In addition, a radical polymerization initiator may be used in combination with a radical polymerization method and a photopolymerization method.

The photopolymerization initiator used during polymerization is not particularly limited, and general photopolymerization initiators can be used.

For example, (a) aromatic ketones such as penzophenone, benzoin, benzoin ethyl ether, benzyl, acetophenone, and 1-hydroxycyclohexylphenyl ketone; (b) aromatic compounds such as anthracene and α-chloromethylnaphthalene; c) Sulfur compounds such as diphenyl sulfide and thiocarbamate can be used.

In addition, aromatic ketones, especially penzophenone,
Preference is given to using 1-hydroxycyclohexyl phenyl ketone.

The radical polymerization initiator that may be used in combination during polymerization is not particularly limited, and general radical polymerization initiators can be used.

For example, organic peroxides such as benzoyl peroxide, diisopropyl peroxycarbonate, tert-butyl peroxyisobutyl peroxide, and di-tert-butyl peroxide can be used.

It is appropriate to use the photopolymerization initiator in an amount of 0.001 to 20 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the sulfur-containing acrylic compound of formula (1).

The radical polymerization initiator is suitably used in an amount of 0 to 10 parts by weight based on 100 parts by weight of the sulfur-containing acrylic compound of formula CI).

A radical polymerization initiator is often used in combination when polymerization cannot be substantially quantitatively completed even if the amount of ultraviolet irradiation is increased.

Method for producing a polymer> The method for producing a high refractive index resin according to the present invention involves photopolymerizing the sulfur-containing acrylic compound of formula [1), and then heating the resulting polymer at 80 to 150°C, preferably at 100 to 130°C. It consists of heating at a temperature of , to make the produced polymer colorless.

The heating time at the above heating temperature is long enough to keep the hue and light transmittance of the colored polymer constant. Therefore, the heating time varies depending on the degree of coloring of the produced polymer, but colorlessness can be achieved in about 0.5 to 10 hours.

Further, the polymerization reaction is preferably carried out by irradiation with ultraviolet rays in the absence of molecular oxygen.

In that case, the wavelength of the ultraviolet rays is 0. 1~600
It is preferred that the nLI1 is preferably 190 to 430 nm. Further, the ultraviolet irradiation is performed in air or inert gas at room temperature to 100°C, preferably room temperature to 60°C.
Preferably, the reaction is carried out at a temperature of .

In this way, first, a monomer consisting of a sulfur-containing acrylic compound of formula CI in the presence of a photopolymerization initiator (or a radical polymerization initiator) is placed in a polymerization container (for example, in a cast polymerization container). photopolymerization or radical polymerization to form a polymer.

The resulting polymer is colored due to some action during the polymerization process. Therefore, in the present invention, the colored produced polymer is heated to make the produced polymer colorless. Heating for decolorization usually involves heating the polymer at 80 to 150°C, preferably 100°C, in air or inert gas after demolding.
This is usually carried out at ~130°C for 0.5 to 10 hours.

Heating may be performed until the hue and/or light transmittance of the polymer becomes constant.

Coloration during the polymerization process is thought to occur due to some kind of interaction between the photopolymerization initiator, the sulfur-containing acrylic compound, and/or trace impurities contained therein, and the generation of substances that cause coloration during ultraviolet irradiation. I can do it.

Furthermore, colorlessness can be considered to be due to the fact that the causative agent of coloration caused by interaction is eliminated by heating.

As the photopolymerization initiator and the radical polymerization initiator, those described above can be used, and the amounts of these polymerization initiators to be used are also as described above.

Similarly, photopolymerization and radical polymerization can be carried out in combination.

When obtaining final products such as optical lenses and prisms, the casting mold is configured to have the same shape as the final product. In addition, if the final product is to be processed by cutting, surface finishing, etc., the shape is configured in consideration of the processing. It is also possible to produce lenses, prisms, etc. by making a polymer block, such as a block or a plate, and then cutting it out or by other means.

Experimental Examples The following experimental examples explain the present invention more specifically. The present invention is not limited in any way by these experimental examples.

Parts in the experiment indicate parts by weight, and the various physical properties obtained in the experimental examples were measured by the following test methods.

(1) Light transmittance: 45% using a 3mm thick test piece
It shows the transmittance of a light beam of 0nII1.

(2) Refractive index and Abpe number: Measured at 25° C. using an Appe refractometer (manufactured by Atago).

(3) Polymerization reaction rate: Determined by measuring DSC (manufactured by Seiko Electronics Co., Ltd.) using the following formula.

Polymerization reaction rate (%) - (1 - (calorific value per unit weight of sample after polymerization) / (heat value per unit weight of sample before polymerization f)
fi)) After stirring and mixing uniformly, the system was evacuated and degassed, and returned to normal pressure with nitrogen.20 After repeating the degassing operation three times, filter through a 0.3 μ filter to thoroughly defoam. This liquid was injected into a mold with a diameter of 5 cm and a thickness of 5 mm made of a glass plate and silicone rubber.Then, using a high-pressure mercury lamp with an output of 80 W/am, the glass plate was poured from a distance of 40 cm. Ultraviolet rays were irradiated through the surface for 10 minutes (5 minutes on each side of the glass plate).The obtained polymer was colored yellow with a light transmittance of 72% and a polymerization reaction rate of 96%.

The polymer was demolded and heated in an air oven at 100° C. for 1 hour and at 130° C. for 1 hour, thereby becoming colorless, with a light transmittance of 92% and a polymerization reaction rate of 100%.

The results obtained are shown in Table 1.

Example 2 100 parts of p-bis(β-methacryloyloxyethylthio)xylylene in Example 1 was replaced with 80 parts of p-bis(β-methacryloyloxyethylthio)xylylene and 2.
2-di[4-(2-methacrylicethoxyethoxy)
A colorless and highly transparent polymer was obtained in exactly the same manner except that 20 parts of phenyl]broban was used. The results obtained are shown in Table 1.

Example 3 A sulfur-containing acrylic compound represented by the following formula was used in place of p-bis(β-methacryloyloxyethylthio)xylylene in Example 1, and 0.2 part of 1-hydroxyhexyl phenyl ketone was added. in place of 0.2 parts of benzoin ethyl ether and 0.2 parts of penzoyl peroxide.
A colorless and highly transparent polymer was obtained in exactly the same manner except that 2 parts were used. The results obtained are shown in Table 1.

Shifl 2shi! '12 0; A colorless polymer with excellent transparency was obtained in exactly the same manner. The results obtained are shown in Table 1.

Example 5 In place of 100 parts of p-bis(β-methacryloyloxyethylthio)xylylene in Example 1, 60 parts of 4,4'-di(β-methacryloyloxyethylthio)diphenylsulfone and m-bis(β-methacryloyloxyethylthio)diphenylsulfone were used. A colorless and highly transparent polymer was obtained in exactly the same manner except that 40 parts of -methacryloyloxyethylthio)xylylene was used. The results obtained are shown in Table 1.

Claims (1)

[Scope of Claims] A colored compound obtained by irradiating ultraviolet rays to radically polymerize a compound consisting mainly of a sulfur-containing acrylic monomer represented by the following formula [I] and a photopolymerization initiator. A method for producing a colorless, high refractive index resin with excellent light transmittance, the method comprising heating a polymer in a temperature range of 80 to 150°C. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (Here, R^1 and R^2 each represent a hydrogen atom or a methyl group, and Ar is an arylene group or aralkylene group having 6 to 30 carbon atoms. , or those groups substituted with a halogen atom excluding fluorine, and X is -O
- or -S-, Y indicates -S- or -SO_2- when X indicates -O-, -S- when X indicates -S-,
-SO_2-, -CO-, each represents an alkylene group, an aralkylene group, an alkylene ether group, an aralkylene ether group, an alkylenethioether group, or an aralkylenethioether group having 1 to 12 carbon atoms, m and n each represents an integer from 1 to 5, p is 0
- Indicates a number of 10. )