JPS6142602A - Synthetic resin lens - Google Patents

Abstract

PURPOSE:To obtain a synthetic resin lens having high dimension stability by consisting said lens of a copolymer contg. methyl methacrylate and phenyl methacrylate respectively in a specific weight % range. CONSTITUTION:The synthetic resin lens consists of the copolymer composed of 10-90wt% methyl methacrylate and 10-90wt% phenyl methacrylate. Any method such as, for example, suspension polymn., emulsion polymn., mass polymn. or soln. polymn. can be adopted to copolymerize these monomer component compsn. A free radical initiator or oxidation-reduction system polymn. initiator, for example, a combination of peroxide and amine is used as the polymn. initiator to be used. Arom. mercaptan, etc, are used for the chain transfer agent for adjusting the degree of polymn.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a synthetic resin lens with high one-dimensional stability.

[Prior art]

Methacrylic resin, whose main component is methyl methacrylate, not only has excellent transparency and weather resistance, but also has well-balanced mechanical properties, thermal properties, moldability, etc. It is used for 8i optical applications.

In particular, when used as optical lenses, it is expected that the demand for it will further increase in the future due to its advantages such as lighter weight and mass production compared to conventional inorganic glasses.

However, on the other hand, methacrylic resin is similar to other transparent materials2.
For example, it has higher hygroscopicity than polystyrene, polycarbonate, etc., and also has disadvantages such as warping, which causes the product to deform when left in a humid environment for a long period of time. For this reason, there are some fields in the field of precision optics where the use of methacrylic resin lenses is restricted; [Problems to be Solved by the Invention] The purpose of the present invention is to The goal is to develop highly stable synthetic resin lenses.

[Means for solving the problems] The synthetic resin lens of the present invention is made of methyl methacrylate) 10
~901L ratio and phenyl methacrylate) 10-9
It consists of 0% by weight of copolymer.

The resin used in the resin of the present invention must contain 10 to 90% by weight of methyl methacrylate as a constituent component. If it is less than 10% by weight, the original properties of the methacrylic resin will be impaired.

Moreover, when the content exceeds 9-Oi%, the effect of reducing hygroscopicity is small. Furthermore, it is important that the second component, phenyl methacrylate, is contained in the copolymer in an amount of 10 to 90% by weight. 10 If the weight is less than 5, there is no effect of reducing hygroscopicity, and if the weight is less than 9
If it exceeds 0% by weight, mechanical properties will deteriorate. Furthermore, as other constituents, other copolymerizable monomers such as methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc., may be used. Up to 20% by weight, preferably 1 to 15% by weight of alkyl (meth)acrylates, cyclohexyl (meth)acrylates, styrene, acrylonitrile, etc. having chain or branch alkyl groups can be introduced.

The resin composed of the above components used in the lens of the present invention can be easily obtained by copolymerizing the monomer component compositions thereof. For the polymerization, any of conventionally known methods such as suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization can be employed.

In the suspension polymerization method, for example, a monomer mixture to which a radical polymerization initiator and a chain transfer agent for controlling the trap molecular weight are added is dispersed in water in which a suspension dispersant is dissolved, and then 50 to 1
The polymerization may be carried out at a temperature range of 30° C. for several hours.

In addition, in the bulk polymerization method by casting, a radical polymerization I initiator is added to a monomer mixture blended in a predetermined ratio, and then poured into a reinforced glass or stainless steel cell fitted with a vinyl chloride frame. For example, 0.3-1 at 45-90℃
It is then carried out for 10 minutes to 5 hours at 80 DEG to 1,50 DEG C. for 5 hours.

The polymerization initiators used in each of the above polymerization methods are 2
For example, diacyl peroxide, peroxy ester,
Dialkyl peroxide.

Examples include free radical initiators such as ketone peroxides and azobis-based compounds.

It is also possible to use a redox polymerization initiator 9, for example, a combination of peroxides and amines. These polymerization initiators can be used not only individually but also in combination of two or more, and the amount used is 0.001 to 1 part by weight per 100 parts by weight of the monomer mixture.

In each of the above polymerization methods, 1) chain transfer agents for adjusting the degree of polymerization include 2, for example, alkyl mercaptans, thioglycolic acid, and esters thereof.

Aromatic mercaptans such as β-mercaptopropionic acid and its esters, thiophenol, and thiocresol are used.

Additionally, antioxidants are added to the resin as necessary.

Antistatic agents, ultraviolet absorbers, mold release agents, and other additives may also be added.

The synthetic resin lens according to the present invention can be produced by injection molding or compression molding a copolymer produced by the above polymerization method, by injecting the monomer mixture or a partial polymer thereof into a lens mold and polymerizing by casting. It can be easily obtained by a method of cutting or polishing a copolymer block.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples and Comparative Examples.

Example 1 2,2'-azobis(
2,4-dimethyl)valeronitrile 0, IP was added and uniformly dissolved. This mixture is injected into the lens mold through the gasket.

It was cured by heating at 65° C. for 6 hours and then at 120° C. for 3 hours. After cooling, the center part was removed from the disk, thickness 3m, diameter 2
The 0m5+ lens has extremely good transparency and two-sided accuracy of 5.
After being left in water at 0° C. for 12 hours, no change was observed in the number of changes in Newton's rings measured by optical measurement. Further, the thermal deformation temperature of this lens was 105° C. according to ASTM-D6j8 method.

On the other hand, when 100% methyl methacrylate was polymerized in the same manner, the number of Newton rings changed was 5.

Example 2 A lens was produced by repeating the same method as in Example 1, except that the monomer composition was changed to methyl methacrylate 60P and phenyl methacrylate 140F. In this lens, no change in Newton's ring was observed, and the thermal deformation temperature was as high as 107°C.

Example 3 Into a 201 glass flask equipped with a stirrer and a reflux condenser, ion-exchanged water of 9000F was added. Next, copolymer 1.27' of sodium salts of methyl methacrylate and 2-sulfoethyl methacrylate and sodium sulfate were added as a dispersant. 30. P was added and dissolved. Then, methyl methacrylate) 3900 P, phenyl methacrylate 1800 /, methyl acrylate 3007
A polymerization raw material prepared by adding and dissolving azobisisobutyronitrile 60F as a polymerization initiator, U-octyl mercaptan 12t as a chain transfer agent, and stearic acid monoglyceride 6, Ot as a mold release agent to a monomer mixture consisting of was put into the flask. After nitrogen substitution, 3
While stirring at 50 rpm, at 80°C for 2 hours, then 9
Polymerization was carried out at 8°C for 2 hours. The obtained bead-shaped polymer was washed with water, separated by F, dried at 75° C. for 24 hours, and extruded into pellets using a 305 m extruder equipped with a vent. The obtained pellets were injection molded at a cylinder temperature of 240° C. and a mold temperature of 60° C., and a lens having a center thickness of 2.5 m and a diameter of 20 mm was obtained.

After this lens was left in water at 50° C. for 12 hours, the number of changes in the number of two Newton rings was as small as 0 to 1.

On the other hand, in the injection molded product of 2 ordinary methacrylic resin (Acrivet VH, Tokama trademark, manufactured by Mitsubishi Rayon Co., Ltd.), the number of Newton rings changed was five.

〔Effect of the invention〕

As mentioned above, the synthetic resin lens of the present invention has lower hygroscopicity and superior two-dimensional stability than conventional methacrylic resin lenses, so it can be used for eyeglasses, sunglasses lenses, and camera lenses.

[In addition to lenses for vehicle lamps, it is useful as optical lenses such as Fresnel lenses, lenticular lenses, and microprism matte lenses that have special shapes that are difficult to process using inorganic materials.

Claims (1)

[Claims] A synthetic resin lens made of a copolymer of 10 to 90% by weight of methyl methacrylate and 10 to 90% by weight of phenyl methacrylate.