JPH0782376A - Production of high-refractive-index resin - Google Patents

Abstract

PURPOSE:To produce an optical resin which is colorless and transparent and has excellent heat and impact resistance, a low specific gravity, a high refractive index, and a low dispersion by reacting a trifunctional or higher thiol compd. with a specific monomer in the presence of a radical polymn. initiator. CONSTITUTION:A trifunctional or higher thiol compd. is reacted with at least one member elected from monomers of formulas I, II, and III in the presence of a radical polymn. initiator, giving the objective resin. In the formulas, R<1> and R<2> are each H or CH3; X is -CH2CH2-, -CH2-Ph-CH2, etc.;R<3> is -CH2CH= CH2 or -CH2CH2-O-C(=O)-C(-R<4>)=CH2 (wherein R<4> is H or CH3); and R<5> and R<6> are each H or CH3. The resin is usable as an optical resin for a lens, a prism, an optical fiber, an optical waveguide, an optical disc, a film, etc., and, when compounded with a pigment, a filler, etc., is usable for a molding for decoration or construction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel high refractive index resin.

[0002]

2. Description of the Prior Art Materials used for manufacturing optical members such as lenses, prisms, optical waveguides, and disk substrates must be colorless and transparent. As a material that can replace the material, transparent synthetic resin is expanding its range of application as an organic optical material because of its light weight, impact resistance, molding processability, and dyeability.

Various properties are required for transparent synthetic resins as optical materials, and among them, the refractive index thereof has a very important effect. For example, when used as a lens, in order to obtain a lens having the same focal length, a transparent synthetic resin having a high refractive index can make the thickness of the lens thinner than a material having a low refractive index. The use of thin lenses reduces the volume of space occupied by the lenses in the optical assembly, which has the advantage of reducing the weight and size of the optical device.

Conventionally, as the resin used as a plastic lens material, diethylene glycol bisallyl carbonate resin, polymethyl methacrylate, polycarbonate, etc. are generally known. Bone resin and polymethylmethacrylate have a small refractive index of 1.49 to 1.50. Therefore, when these resins are molded into a plastic lens, the center thickness, edge thickness and curvature are smaller than those of an inorganic optical glass lens. Has the drawback that it becomes large. In addition,
Bone has a high refractive index of 1.58 to 1.59, but birefringence is apt to occur during molding, and there is a drawback in optical uniformity. In addition, polymethyl methacrylate and polycarbonate
Since the resin is a non-crosslinked thermoplastic resin, the resin is fused during cutting and ball-sliding, and in fields where such processing is required, such as lenses for precision optical equipment, optical elements and eyeglass lens materials. I was not satisfied with it.

In order to improve the above-mentioned drawbacks of the thermoplastic resin, a method for producing a resin having a crosslinked structure by using ethylene glycol dimethacrylate as a crosslinking agent is conventionally known. -The resin obtained by using rudimethacrylate has poor impact resistance.

Further, Japanese Patent Application Laid-Open No. 62-34102 discloses an example of using a styrene derivative in which an aromatic ring is substituted with halogen as a high refractive index component. The use of this compound increases specific gravity and light resistance. It has the disadvantage of poor sex.

Further, Japanese Patent Application Laid-Open No. 5-70524 discloses that an optical resin is obtained by subjecting a bifunctional thiol compound and a bifunctional vinyl compound to an addition reaction. With this combination, a high density three-dimensional resin is obtained. No crosslinked product was obtained,
The two-dimensional linear polymer is formed in a considerable proportion, and there is a drawback that only a resin having poor machinability and heat resistance can be obtained. Further, JP-A-5-142501 discloses that an eyeglass lens is obtained by addition-reacting a trifunctional thiol compound and a bifunctional vinyl compound, but dimethacrylate having a sulfur atom directly bonded to an aromatic ring is an essential component. However, there is a drawback in that coloring is inevitable due to this compound. The cause of the coloring is not clear, but it is speculated that it may be due to the resonance delocalization of the electrons via the sulfur atom.

[0008]

An object of the present invention is to provide a method for producing a resin for optical materials, which is excellent in colorless transparency, heat resistance and impact resistance, has a low specific gravity, and has a high refractive index and a low dispersion. is there.

[0009]

Means and Actions for Solving the Problems The inventors of the present invention have made extensive studies in view of such a situation, and as a result, initiated a radical polymerization of a monomer component having a specific composition and a trifunctional or higher functional thiol compound. The resin obtained by polymerization in the presence of an agent solves the above problems, and is found to be colorless and transparent, heat resistant, and has excellent impact resistance, low specific gravity, high refractive index, and low dispersion, thus completing the present invention. It has come to do.

That is, the present invention relates to a method for producing a high refractive index resin, wherein a trifunctional or higher functional thiol compound and the general formula (1) are used.

[0011]

[Chemical 4]

[In the formula, R ¹ and R ² are independently H or CH ₃ , and X is -CH ₂ CH ₂ -,-(CH ₂ CH ₂ O) _n -CH ₂ CH _2- , -CH ₂
-Ph-CH ₂ -,-(CH ₂ CH ₂ S) _m -CH ₂ CH _2- (where m and n are 1 to
It is an integer of 3. ) Represents. ] The monomer (b
1), general formula (2)

[0013]

[Chemical 5]

(In the formula, R ³ is -CH ₂ CH = CH ₂ or -CH ₂ CH ₂ -O.
-C (= O) -C (-R 4) = CH 2 ( where, R ⁴ is H or CH _3.) Represents the. ) And a general formula (3)

[0015]

[Chemical 6]

(Wherein R ⁵ and R ⁶ each independently represent H or CH ₃ ) and at least one monomer (B) selected from the group consisting of monomers (b3). The present invention relates to a method for producing a high-refractive-index resin, which comprises reacting a resin in the presence of a radical polymerization initiator.

Examples of the monomer (b1), the monomer (b2) and the monomer (b3) used in the present invention include:
2-bis [(meth) acryloylthio] ethane, bis [2- (meth) acryloylthioethyl] ether, bis [2- (2- (meth) acryloylthioethoxy) ethyl] ether, 1,4 -Bis [(meth) acryloylthiomethyl] benzene, bis [2- (meth) acryloylthioethyl] sulfide, 1,2-bis [2- (meth)]
Acryloylthioethylthio] ethane, diallyl diphenate, di (meth) acryloyloxyethyl diphenate,
2,2-bis [(4- (meth) acryloyloxyethoxy) -2,6-dibromophenyl] propane and the like can be mentioned, and one or more of these can be used.

Examples of the trifunctional or higher functional thiol compound used in the present invention include trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthiopropionate and trimethylolpropane tristhiopropionate. -, Pentaerythritol tetrakisthioglycolate and the like. The high refractive index resin according to the present invention comprises a trifunctional or higher functional thiol compound and a monomer (b).
1), at least one monomer (B) selected from the group consisting of the monomer (b2) and the monomer (b3), but optionally other copolymerizable monomer. A monomer may be contained to such an extent that the present invention is not impaired.

In the manufacturing method of the present invention, the heat resistance is excellent, and fusion or clogging is less likely to occur during cutting or ball-sliding (when the surface of a lens or the like is rubbed), and the resin component is not attached to the processing tool. In order to obtain a heat-resistant high refractive index resin, a trifunctional or higher functional thiol compound and a monomer (b
1), the amount of the monomer (b2) and the amount of the monomer (b3) used are the ratio of the functional group equivalents, that is, the thiol group / double bond group is 1
It is preferably used in the range of / 10 to 1/1. Thio
Group / double bond group is less than 1/10, ie thio-
When the amount of the thiol compound is small, the effect of the addition of the thiol compound is small, and the resin tends to have poor impact resistance. Further, when the thiol group / double bond group is larger than 1/1, that is, when the thiol compound is excessive, the crosslink density does not increase and at most a rubber-like resin is obtained, and it is difficult to maintain the shape.

Radical polymerization initiators that can be used in the polymerization include, for example, benzoylperoxide, acetylperoxide, di-t-butylperoxide, diisopropylperoxydicarbonate, t-butylperoxide.
Peroxides such as oxy-2-ethylhexanoate and 2,
Examples thereof include azo compounds such as 2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), and 1,1′-azobis (cyclohexane-1-carbonitrile). It is possible to add one or more of these to 0.01 to 1 with respect to the polymerizable monomer component.
If necessary, it may be used in combination with an accelerator in an amount of 0% by weight, preferably 0.05 to 5% by weight.

The polymerization conditions cannot be unconditionally limited because they are influenced by the type of polymerizable monomer, the composition ratio and the type of polymerization initiator, but generally the polymerization is started at a relatively low temperature and the temperature is slowly raised. A polymerization method in which post-polymerization is performed at a high temperature at the end of the polymerization to cure the composition is preferable. Further, since the polymerization time varies depending on various conditions, it is preferable to determine the optimum time according to these conditions in advance, but generally 2
It is preferable to select the conditions so that the polymerization is completed in about 40 hours.

The high refractive index resin produced by the production method of the present invention may optionally contain known additives such as an ultraviolet absorber, an antioxidant, a drip-proofing agent and a coloring agent.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples.

<Example 1> 24.4 parts by weight of bis (2-methacryloylthioethyl) sulfide, trimethylo-
2040 parts by weight of propane tris thioglycolate,
A mixture of 0.088 parts by weight of 2,2'-azobis (2,4-dimethylvaleronitrile) and 0.088 parts by weight of azobisisobutyronitrile was used as a model consisting of two glass plates and a gasket made of silicon rubber. -Injected into the field, 5
The temperature was maintained at 0 ° C for 6 hours, and then the temperature was raised to 110 ° C over 16 hours to polymerize. Further, it was kept at 110 ° C. for 2 hours to carry out post-polymerization. The obtained high refractive index resin [1] was colorless and transparent. Various physical properties of this high refractive index resin were measured by the following methods and the results are shown in Table 2.

-Physical Property Evaluation Method- (Colorless transparency) The degree of coloring of the polymer obtained by the cast polymerization was visually evaluated.

(Refractive Index and Abbe's Number) A small piece of the polymer obtained by the cast polymerization was measured for its refractive index with an Abbe's refractometer (manufactured by Atago Co.) in accordance with JIS K7105. The value of the number was calculated.

(Total Light Transmittance) The polymer obtained by cast polymerization was measured using a turbidimeter (manufactured by Nippon Denshoku Co., Ltd.). The thickness of the test piece was 1.5 mm.

(Machinability) The polymer obtained by cast polymerization was cut with a diamond cutter, and the presence or absence of cracks, cracks, fusion or the like on the cut surface was visually observed. Items with no cracks, cracks, or fusion were marked with a circle.

(Heat resistance) The polymer obtained by casting polymerization was
It was placed in a hot air dryer at 00 ° C. for 3 hours, and the deformation of warpage and the like at that time was visually observed. The ones in which no deformation was observed were marked with a circle.

<Examples 2 to 7> High refractive index resins [2] to [7] were obtained in the same manner as in Example 1 except that the composition of the polymerizable monomer component was as shown in Table 1. It was Evaluation of various physical properties was performed in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 1 29.1 parts by weight of tetraethylene glycol dimethacrylate and 20 parts by weight of trimethylolpropane tristhioglycolate and 2,2'-azobis (2,4-dimethylvaleronitrile) 0.098
A mixed solution of 1 part by weight and 0.098 parts by weight of azobisisobutyronitrile was poured into a mold consisting of two glass plates and a gasket made of a silicon rubber and kept at 50 ° C. for 6 hours. The temperature was raised to 16 ° C over 16 hours to polymerize.
Further, the mixture was kept at 110 ° C. for 2 hours and then post-polymerized. Various properties of this comparative resin [1] were measured in the same manner as in Example 1, and the results are shown in Table 4.

Comparative Examples 2 to 10 Comparative resins [2] to [10] were obtained in the same manner as in Comparative Example 1 except that the composition of the polymerizable monomer component was as shown in Table 3. . Various physical properties were evaluated in the same manner as in Example 1, and the results are shown in Table 4.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

Abbreviations in Tables 1 to 4 BMTEE: Bis (2-methacryloylethyl) ether BMTES: Bis (2-methacryloylethyl) sulfide BMTMB: 1,4-bismethacryloylthiomethylbenzene DMDS: Bis (2 -Mercaptoethyl) sulfide DPDA: diallyl diphenate 4EG: tetraethyleneglycol dimethacrylate MPS: bis (p-mercaptophenyl) sulfide PETP: pentaerythritol tetrakisthiopropionate St: styrene TMPTG: trimethylol Propane tristhioglycolate V-65: 2,2'-azobis (2,4-dimethylvaleronitrile) AIBN: azobisisobutyronitrile BDT: 1,4-benzenedithiol HDAP: 2-hydroxy-1, 3-Diacryloxypropane DVB: Divinylbenzene MPSMA: Bis [(4-methacryloylthio) phenyl] Rufido TMPTP: trimethylolpropane - Le propane tris (beta-Chiopuropione - DOO) TMPTM: trimethylolpropane - Le propane trimethacrylate TBAM: 2,2-bis (4-methacryloyl-ethoxy-3,5-dibromophenyl) propane

[0038]

The high refractive index resin obtained by the production method of the present invention is a trifunctional or higher functional thiol compound and a monomer (b).
1), at least one monomer selected from the group consisting of the monomer (b2) and the monomer (b3) is used as an essential component, so that the refractive index is high and the transparency is excellent. Since it is also excellent in heat resistance and machinability, it is used as a resin for optical materials, for example, as a member such as a lens, a prism, an optical fiber, an optical waveguide, an optical disk, a film, etc., and further mixed with a pigment, a filler, etc. for decoration. It can also be used for building materials.

The present invention provides a method for easily obtaining a high refractive index resin having such characteristics.

Claims (2)

[Claims] 1. A trifunctional or higher functional thiol compound (A) and a compound represented by the general formula (1): [Wherein R ¹ and R ² are each independently H or CH ₃ ,
X is -CH ₂ CH ₂ -,-(CH ₂ CH ₂ O) _n -CH ₂ CH _2- , -CH ₂ -Ph-CH _2- ,
- represents a (where, m, n is an integer of 1 to _{3.) - (CH 2 CH 2} S) m -CH 2 CH 2. ] The monomer (b1) represented by the general formula (2): (In the formula, R ³ is -CH ₂ CH = CH ₂ or -CH ₂ CH ₂ -OC (= O) -C (-
R ⁴ ) = CH ₂ (wherein R ⁴ is H or CH ₃ ). ) A monomer (b2) represented by the formula (3) and a general formula (3): (In the formula, R ⁵ and R ⁶ each independently represent H or CH _3. ) Radical polymerization with at least one monomer (B) selected from the group consisting of monomers (b3) A method for producing a high refractive index resin, which comprises reacting in the presence of an initiator. 2. A ratio of functional group equivalents of a thiol group in a trifunctional or higher functional thiol compound (A) and a double bond group in a monomer (B), that is, thiol group / diamine. Heavy bond groups are 1/10 to 1 /
1. The method for producing a high refractive index resin according to claim 1, wherein