JPS58142931A - Optical resin composition and optical element - Google Patents

Abstract

PURPOSE:To prepare a resin composition having low temperature dependency of the refractive index and low linear expansion coefficient and giving an optical element having high thermal stability, by using a vinyl polymer obtained by reacting a monomer in the presence of a specific amount of crosslinking agent, as a main component. CONSTITUTION:The objective polymer is prepared by adding 0.001-20wt%, preferably 0.5-10wt% crosslinking agent to a vinyl monomer such as styrene, alkyl (oxy) styrene, methacrylate monomer, conjugated nitrile, etc., and subjecting the mixture preferably to bulk polymerization or suspension polymerization. The weight-average molecular weight of the produced polymer is preferably 100,000-1,000,000. The crosslinking agent is a compound having two or more polymerizable double bonds, such as aromatic divinyl compound (e.g. divinylbenzene) diethylenic carboxylic acid ester (e.g. ethylene glycol dimethacrylate), etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic optical element made by injection layering, compression molding, etc., and an optical resin composition used therein.

Plastic optical elements are lighter than glass ones.
High impact resistance, no polishing required, easy mass production.
Demand for aspherical lenses has been increasing in recent years because they have advantages such as being able to be mass-produced. However, compared to glass optical elements, plastic optical elements have poor precision due to the temporal characteristics of the image on the structure or the plastic material itself, and also have a small range of refractive index selection and large birefringence. However, these problems have been factors that have hindered the use of plastic optical elements until now. Plastic optical elements sometimes have linear expansion coefficients that are one order of magnitude larger than those made of glass (as a result, surface precision deteriorates due to temperature changes, and optical element design is constrained by the large temperature dependence of the refractive index). There have been major problems such as the development of plastic optical elements with better thermal stability and a smaller coefficient of linear expansion.

Therefore, an object of the present invention is to provide an optical resin composition and an optical element TM having good thermal stability.

Another object of the present invention is to provide an optical resin composition and an optical element whose refractive index has low temperature dependence.

Still another object of the present invention is to provide an optical layer IIIi111 (acid and optical element) in which the surface precision is less deteriorated due to temperature changes.

The object of the present invention is to use as a main component a vinyl polymer (hereinafter referred to as the polymer of the present invention) obtained by adding and reacting at least one crosslinking agent of o, ooi to 2 L) by weight to one monomer. This is achieved by an edible optical resin composition and an optical element obtained by molding the resin composition.

The crosslinking agent used in the production of the polymer of the present invention is a compound having two or more polymerizable double bonds, such as aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof, e.g. ethylene glycol dimethacrylate, ethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate), trimethy4-propane cyacrylate, allyl methacrylate 1, 1
″□・.

? ) Laethylene glycol dimethacrylate, 1゜3
Examples include all divinyl compounds such as diethylenic carboxylic acid esters such as -butanediol dimethacrylate, divinyl ether, and compounds having three or more vinyl groups such as divinyl acrylate F. The crosslinking agent may be used alone or in combination of two or more types. The amount of the crosslinking agent is suitably in the range of 0.001 to a) weight based on the total monomer weight.

If the amount added is too large than this range, it becomes insoluble and infusible, giving unfavorable results in terms of molding.On the other hand, if the amount added is too small, the effect tends to be weakened. The amount of crosslinking agent is more preferably in the range of 0.5 to 10% by weight, although there is a trade-off with the molecular weight of the articulating agent.

When a crosslinking agent is added, the polymer has a high molecular weight, and if the amount is increased excessively, a network structure develops, making it impossible to mold. In order to suppress this, molecular weight regulators, generally called chain transfer agents, are used to capture chains in the process of growth.
At the same time, the chain species that has been subjected to m* can be converted to ζ7 using a species that stops the increase in molecular weight and starts the chain reaction again.

The type and amount of the molecular weight modifier are selected depending on the degree of molecular weight control, but examples of those that are effective in extremely small amounts include mercaptans such as lauryl mercaptan, phenyl mercaptan, butyl mercaptan, and dodecyl mercaptan; , carbon tetrabromide and other halogenated carbons, and those that are effective in relatively large amounts include substituted aromatic compounds such as silene and isopropylbenzene, and substituted fatty acids such as trichloroacetic acid and tribulium acetate. There is. Examples of monomers that are added as polymerized monomers and are also effective as molecular weight regulators include psobylene, imbutylene, α-methylstyrene, allylbenzene, allyl acetate, Examples include allyl compounds such as aryl chloride. The molecular weight joint agents may be used alone or in combination of two or more.

For the purpose of the present invention, it is advantageous for the molecular weight regulator to be added in an amount of θ to 20% by weight relative to the monomer during the polymerization reaction of the polymer of the present invention.

The polymer of the present invention, that is, the vinyl polymer that makes up the majority of the optical resin, may be a homopolymer of vinyl monomers or a copolymer of two or more vinyl monomers. Typical monomers used to prepare the polymers of the present invention include styrene, p-styrene, p-styrene,
atomized styrene, and halogenated styrenes having a plurality of tetragene substituents on benzene, tert-butylstyrene, tert-74 styrene, alkyl-based styrene such as vinyltoluene, phenoxy group on benzene,
Alkyloxystyrenes having one or more alkyloxy groups such as pendoxy groups, alkylthiostyrenes having one or more alkylthio groups such as benzene and ruthio groups, mercapto groups, methyl methacrylate, cyclohexyl methacrylate , Ryoda! methyl methacrylate, 2-methyl cyclohexyl methacrylate, isobobenyl methacrylate, dalicidyl methacrylate, and Seibon II! $1-2519 Yahoki A series of methacrylic acid ester monomers used in the synthesis of streamers, conjugated nitrile counterfeits such as atari tetra-tolyl and methacrylate tril, bi-1-luna-7-talene, N-vinylcarbasol, etc. can be mentioned.

Examples of the formulation for producing the polymer tube of the present invention include, but are not limited to, the following.

The weight average molecular weight of the polymer is 5oooo~3000
000 is used, particularly preferably 10,000
0 to 1,000,000 is used.

The polymerization reaction equipment used to produce the polymer of the present invention is a generally used reaction equipment [can be used as is, and polymerization methods include bulk polymerization, 1l1111 polymerization,
Polymerization methods such as solution polymerization and enveloping polymerization may be used, but bulk polymerization and suspension polymerization are preferred.

The resin composition according to the present invention may contain an ultraviolet absorber in order to improve light resistance. As the ultraviolet absorber, it is not preferable to use one that reduces the transmittance in the visible region, but any ultraviolet absorber may be used as long as it effectively absorbs ultraviolet light without damaging the properties of other resins. Specific examples include Orthohi, Dokisalicil 7-crystalline chemical compound,
2-(e-
Benzotriazole compounds, cyanoalaryl compounds, etc. can be used.

In the present invention, the term "polymer e of the present invention as a main component" refers to approximately 95% of the resin composition of the present invention.
It means that it is a polymer of the invention with a weight ratio of 0.

In addition to the injection method, the method for manufacturing optical elements by layering the resin composition according to the present invention is the compression layering method or the four-linas method, which is a compromise between injection method and compression molding. Micromolding method, etc. Approximately one resin rt'fII
Any method of melting or melting may be applied.

In addition, since moisture absorption of a closed product can have a large effect on the thermal stability of a closed product, in order to improve the dimensional stability of the closed product, the surface of the capped product should be coated with resin and inorganic substances. Applying a coating may be used to prevent moisture absorption costs and improve dimensional stability. Examples of surface resin coating methods include mono! -Or prepoli! Examples include a method of applying a primer solution and then curing it by polymerization and curing by enthusiastic combination, electron beam polymerization, etc., a method of applying a primer solution, and a method of plasma polymerization.

Resins for surface coating include fluoro-alkylenes such as tetra7tethylene, organosilanes such as teshitsumethylsilane, orthosilicates such as tetraethyl orthosilinate, and pentafluoroethyl methacrylate.
Examples include polymers containing fluorocarbon alkyl methacrylates such as F, conjugated nitrites such as acrylonitrile, and styrenes such as styrene and polystyrene as a heptamer component.

Methods for coating with an inorganic substance include vapor deposition, sputtering, ion blating, etc., and examples of the inorganic substance used include fluoride, silium, magnesium oxide, and silicon.

Optical elements obtained by producing the resin composition of the present invention include so-called lenses for still cameras, video cameras, telescopes, eyeglasses, contact lenses, solar concentrators, etc. Prisms such as pentaprisms, concave mirrors, glass mirrors, optical fibers, light guide elements such as optical waveguides, video discs, audio discs, etc., perform functions by transmitting or returning light. Motoko [says]

Hereinafter, the present invention will be specifically explained with reference to Example 1. Example 1 In a series of steps in which a polymerization pot, an extruder, and a monomer removal device are connected so that the above composition can be continuously polymerized. The temperature t of the polymerization kettle was set at a controlled temperature between 130°C and 140°C to obtain a resin composition.

This polymer had a weight average molecular weight of 300,000 and a glass transition temperature of 110°C.

Jv! using this polymer and adding additives such as a heat stabilizer and ultraviolet Jl@absorbent! Once the temperature was set to 220°C, injection was carried out to produce a lens product.

This will be referred to as lens-1.

Comparative Example 1 A lens-covered product was produced in the same manner as in Example 1 except that α-methylstyrene and divinylbenzene were not used. This will be referred to as comparative lens-1.

The above composition was superimposed in the same manner as in Example-1 to obtain a resin composition.

The weight average molecular weight of this resin was 350,000, and the glass transition point was 112°C.Using this resin composition, injection molding was performed at a temperature of the resin composition of 230°C to create a lens. Let be lens-2.

Comparative Example 2 A lens molded product tube was prepared using Example H-2 and rR#A except that ethylene glycol dimethacrylate was not layered. This will be referred to as comparison lens-2.

Example 3 1 part of calcium phosphate, 0.01 part of sodium dodecylbenzenesulfonate, and 200 parts of distilled water were prepared in a reaction pot equipped with a cooling tube, nitrogen introduction tube, stirring bale, and temperature needle, and the above composition was added thereto. , polymerization was carried out at 80° C. for 3 hours. After the polymerization was completed, the resin composition was treated with hydrochloric acid, washed with water, filtered and dried to obtain a resin composition tube. The weight average molecular weight of this resin composition was 500,000, and the glass transition temperature was 90°C.

Using this resin composition, a lens molded product was prepared by subjecting it to compression at a resin temperature of t220'c.

This will be referred to as lens-3.

Comparative Example 3 A lens leakage product was prepared in the same manner as in Example 3 except that α-methylstyrene and F-limethylolpropane triacrylate were not used.

This will be referred to as Comparison Lens-3.

Comparative Example 4 A resin composition was obtained in the same manner as in Example 3, except that trimethylolpropatriacrylate (T2111) was used.

This resin composition was heated blindly at 280°C to form a compression acid 11, but it was insoluble and infusible and could not be layered.

The comparative test results of these lens samples are summarized in Table-1.

Table-1 Note (1) If the refractive index change was measured by the minimum deviation angle method.

(2) The binding tension was measured using a plastic micrometer.

From the above results, it can be seen that the lens sample produced using the SRS compound according to the present invention has a small temperature dependence of refractive index and a small MS tension coefficient, and is a lens with good thermal stability.

Substitute Yoshikazu Kuwabara

Claims (1)

[Claims] (1) Optical resin I11, which contains as a main component a vinyl polymer made by reacting monomers with at least one crosslinking agent of 0.001 N2L1 weight ratio◎
(2) An optical product obtained by laminating a resin composition containing a vinyl polymer as a main component, which is obtained by adding and reacting at least one type of crosslinking agent with a weight of 0.001 to 100% to a monomer. element.