JPS59136310A - Resin for lens - Google Patents

Abstract

PURPOSE:To provide the titled resin having high refractive index and small aberration, by polymerizing tribromophenyl methacrylate, benzyl methacrylate, polyethylene glycol di(meth)acrylate and brominated phenyl acrylate at specific ratios. CONSTITUTION:The objective resin having an Abbe number of >=34, preferably >=35 and a refractive index of >=1.55, preferably >=1.58 can be prepared by polymerizing a mixture containing (A) 40-90wt%, preferably 50-80wt% of tribromophenyl methacrylate, (B) 5-50wt%, preferably 15-35wt% of benzyl methacrylates, (C) 2-30wt%, preferably 5-20wt% of one or more polyethylene glycol di(meth)acrylates of formula (R is H or methyl; n is 1-23) and (D) 3- 40wt%, preferably 5-30wt% of one or more brominated phenyl acrylates having 1-5 bromine atoms on the aromatic ring. EFFECT:It has excellent surface hardness, impact resistance, processability, and heat resistance and low moisture absorptivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin composition for a lens that has a refractive index of about 100% and has small aberrations.

Various studies have been conducted on synthetic resins for lenses that can replace inorganic glass. Examples of these include polydiethylene glycol bisallyl carbonate (hereinafter abbreviated as CR-39), polymethyl methacrylate, polycarbonate, and polystyrene. However, CR-39 and polymethyl methacrylate have the advantages of being lightweight and impact resistant, but have a refractive index of 1.
While polycarbonate and polystyrene have a high refractive index of 159, they have the drawback of large chromatic aberration. In recent years, research has been conducted to produce resins with high refractive index and small chromatic aberration, and Japanese Patent Application Laid-open No. 13747/1983 describes di(meth)acrylic esters, (meth)acrylic esters, or styrene. There is a description of a high refractive index resin composition obtained by copolymerizing a monomer with a monomer having a chlorine, bromine or iodine atom in an aromatic ring, and carbonates in JP-A-54-77686. Alternatively, there is a description of a transparent high refractive index resin composition obtained by copolymerizing with (meth)acrylic acid esters.

The resin composition thus obtained has a refractive index of 1.60.
It is stated that the lens has a high light transmittance of 85% or more, and has a small chromatic aberration. However, monomers with chlorine, bromine, or iodine atoms in their aromatic rings become solid needle-like crystals at room temperature as the amount of halogen atoms they contain increases. It is extremely difficult to degas, the polymer is extremely brittle, and its heat resistance and weather resistance are also unsatisfactory. Moreover, if the above monomer is dissolved in (meth)acrylic acid esters,
Cast polymerization is possible in the same process as with ordinary liquid monomers, but even in this case, as the content of the monomer increases, the impact strength, heat resistance, and weather resistance of the resulting polymer also decrease. do.

We, the inventors, conducted research aimed at obtaining a resin for lenses that has a high refractive index, low chromatic aberration, and has excellent transparency, impact resistance, and heat resistance.As a result, we found a composition that generally has tribromophenyl methacrylate as its main component. However, the remaining monomers in the resin can be reduced by copolymerizing specific monomers in a specific ratio. They discovered that it is possible to obtain a resin that has a high refractive index and low chromatic aberration, and also satisfies the transparency, impact resistance, heat resistance, weather resistance, etc. desired as a resin for lenses.
This invention was completed.

In other words, this invention provides ``'C(A
)) Lipromophenyl methacrylate 40-90% by weight [B] Benzyl methacrylate 5-50% by weight (C)
At least one compound represented by the general formula (l)
30% by weight II n II OO and [D] At least one type of brominated phenyl acrylate having 1 to 5 bromine atoms in the aromatic ring. , a lens resin having a refractive index of at least 1.55.

In this invention, the content of tribromophenyl methacrylate is 40 to 90% by weight, preferably 50 to 80% by weight.
is suitable. The higher the content of tribromophenyl methacrylate, the better the refractive index, hardness, heat resistance, hygroscopicity, and heat resistance of the resulting resin. However, if the content of tribromophenyl methacrylate exceeds 90% by weight, impact The strength decreases significantly, and along with the decrease in the polymerization rate, the heat resistance and weather resistance also decrease. On the other hand, if the content of tribromophenyl methacrylate is less than 40% by weight, the refractive index value is small and the object of the invention cannot be achieved.

The content of benzyl methacrylate is preferably 5 to 50% by weight, preferably 15 to 35% by weight. If the content of methyl methacrylate is less than 5% by weight, not only will it be difficult to dissolve tribromophenyl methacrylate, but the dissolved tribromophenyl methacrylate will not precipitate during various processes such as injection into a mold and degassing. Workability deteriorates as it is necessary to maintain the temperature at a high temperature, and as a result, defects such as polymerization distortion are likely to occur.

If the content of methyl methacrylate exceeds 50% by weight, the refractive index and heat resistance will decrease.

Polyethylene glycol di(
As a meth)acrylate, diethylene glycolzo(
meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate
Examples include those in which the average molecular weight of the acrylate and polyethylene glycol moieties is 400.600.1000.

The content of the compound represented by the general formula (■) is suitably 2 to 30% by weight, preferably 5 to 20% by weight. General formula (
If the content of the compound represented by I) is less than 2% by weight, the resulting resin composition will have insufficient impact resistance, and if it exceeds 30% by weight, the resulting resin will contain a large amount of unpolymerized residual monomers. Not only does the heat resistance decrease, but also the shrinkage of the polymer increases at the end of polymerization, which tends to cause partial peeling of the resin composition from the mold surface, resulting in poor surface properties.

In general formula (T), the value of n is preferably in the range of 1 to 23, and among these, 4 to 23 are particularly effective in improving impact resistance.
The range is 20.

The content of the brominated phenyl acrylate having 1 to 5 bromine atoms in the aromatic ring used in this invention is suitably 3 to 40% by weight, preferably 5 to 30% by weight. If the content of brominated phenyl acrylate is less than 3% by weight, the desired effect of reducing residual monomers will be small, and if it exceeds 40% by weight, although the residual monomers will be reduced, heat resistance will decrease and A partial peeling phenomenon occurs. That is, in this invention, by using a brominated phenyl acrylate having 1 to 5 bromine atoms in the aromatic ring, a high polymerization rate can be obtained without a significant decrease in refractive index or transparency. can.

According to the present invention, the composition has the above-mentioned composition, the Abbe number, which is a measure of chromatic aberration, is 34 or more, preferably 35 or more, and the refractive index is 15.
It is suitably used for lenses having a diameter of 5 or more, preferably 158 or more. Resin can be obtained.

The resin composition of the present invention can be obtained by conducting polymerization in a suitable mold in the presence of a polymerization initiator. Examples of such polymerization initiators include lauroyl peroxide, benzoyl peroxide, dicumyl peroxide, di-t-late, t-butylperoxy-2-ethylhexanoate, di-t-butylshiba-oxyisophthalate, and the like. Organic peroxides or 2,21-azobisisopropyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1-azobis-1-'iohexanecarbonitrile, dimethyl-2,2'-azo Known radical initiators such as bisisobutyrate can be used alone or in combination.

As described above, the lens resin composition of the present invention not only has a higher refractive index than conventionally known CR-39 and polymethyl methacrylate, and has smaller chromatic aberration than polycarbonate and polystyrene, but also has surface properties necessary for a lens resin. , has surface hardness, high impact resistance, excellent workability, high heat resistance, and low moisture absorption, so lenses made from this resin composition have excellent morphological stability during use.

Additionally, known ultraviolet absorbers such as salicylic acid esters, benzophenones, and benzotriazoles, higher alcohols, higher fatty acids, and mold release agents such as wax can be added to this resin composition.

The present invention will be specifically explained below with reference to Examples.

Example 1 After heating and dissolving 20 parts by weight of tribromophenyl acrylate and 20 parts by weight of tribromophenyl acrylate in 25 parts by weight of benzyl methacrylate at 50°C, 5 parts by weight of n-14 polyethylene glycol dimethacrylate was added, and further evaporated. 0.05 parts by weight of lauroyl oxide was added and stirred.

Insoluble materials were removed through a filter, and the mixture was poured into a plate-making glass cell prepared by sandwiching a vinyl chloride gasket between two flat glass sheets spaced apart by 5 mm.

After degassing under reduced pressure, polymerization was carried out at 70°C for 2 hours, and further 1
After being left at 30°C for 2 hours, it was cooled to obtain a 5 mm flat plate. The refractive index of this plate was measured at 25° C. with an Atsube refractometer and was 1,661, and the Atsube number was 9,351. In addition, the total red light transmittance is 91%, the residual monomer is 09%, and the Pickert softening point (v, s, p,)
was 124°C.

As a measure of the impact resistance of the obtained plate, cutting with a circular saw cutter, drilling with a drill press, etc. were attempted, and it was found that it had sufficient workability as a plastic material for lenses.

The outline of the cutter and drill press used in the test is as follows.

Circular saw cutter Ball chick model %formula% Rake angle O.

Lead angle: 20° 1' - Outer diameter barb angle: 15° Examples 2 to 9, Comparative Examples 1 to 6 Table 1 shows the physical properties of the compositions prepared in the same manner as in Example 1.
Shown below. For comparison, commercially available plastic materials for lenses are also listed. This clearly shows that the composition of the present invention has excellent physical properties.

11- Table 1 −13− 　 　 　 　 　 　 　 　 　

=12- Note: Workability is a comprehensive judgment based on the results of cutting, cutting, drilling, etc., and is indicated as O: Good, Δ: Poor, ×: Significantly poor.

TBPMA...tribromophenyl methacrylate B
ZMA...Benzyl methacrylate BPA
...Brominated phenol acrylate () is the number of bromine atoms PEGMA...Polyethylene glycol dimethacrylate) is the value of n CR-39...Polydiethylene glycol bisallyl carbonate p, c...Polycarbonate p st...Polystyrene patent L! , 1 person Kyowa Gas Chemical Industry Co., Ltd. r8
-14- Procedural amendment (
Method) 1. Indication of the incident Japanese Patent Application No. 1982-10968 2, Name of the invention: Resin for lenses 3, Person making the amendment 4, Date of the amendment order: April 6, 1988 Description on page 13, Table 1, and page 14 of the specification shall be corrected as shown in the attached sheet. (There are no changes to the content.)

Claims (1)

[Scope of Claims] 1) [A] 40 to 90% by weight of tribromophenyl methacrylate, [B] 5 to 50% by weight of benzyl methacrylate, and (C) at least one of the compounds represented by general formula (I) based on the total amount of the monomer mixture. Atsube number obtained by polymerizing a mixture containing 2 to 30% by weight of one type RR 100 and (D) 3 to 40% by weight of at least one type of brominated phenyl acrylate having 1 to 5 bromine atoms in the aromatic ring. 34 and a refractive index of at least 155.