JPH05307103A - Optical lens - Google Patents

Abstract

PURPOSE:To provide the optical lens consisting of a crosslinked copolymer having excellent physical characteristics of a high crosslinking density, excellent heat resistance and solvent resistance, and low sp. gr. and good optical characteristics. CONSTITUTION:This optical lens consists of the crosslinked copolymer obtd. by copolymerizing a monomer mixture into which a monomer mixture consisting of 50 to 90wt.% 1,12-stearyl dimethacrylate or 1,12-stearyl diacrylate (component A) and 10 to 50wt.% monomer (component B) expressed by formula is contained at least at 80wt.% ratio. In the formula, R denotes a 6 to 22C alkyl group and X denotes a hydrogen atom or a methyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical lens, and more particularly to an extremely lightweight optical lens made of a crosslinked copolymer.

[0002]

2. Description of the Related Art Conventionally, various inorganic glass lenses have been used in optical lenses, but recently,
Synthetic resin lenses have started to be widely used with inorganic glass lenses because of their lightness, processability, stability, dyeability, mass productivity, and cost reduction potential.

Of the various physical properties required for optical lens materials, low specific gravity is extremely important. By using an optical lens made of a material having a small specific gravity, for example, it is possible to reduce the weight of a lens system that occupies an important position in an optical device such as a microscope, a camera, a telescope, or a spectacle lens. For this reason, even synthetic resin lens materials tend to have a lower specific gravity and emphasize their superiority to inorganic glass lens materials. For example, the most widely used synthetic resin lens material for spectacles at present is a diethylene glycol bisallyl carbonate resin called "CR-39". The specific gravity of this resin is 1.3
1 (refers to a value at a temperature of 20 ° C., the same applies below). Further, recently, an optical lens material containing a halogen atom or a sulfur atom has been known as a high refractive index lens material, and the specific gravity of such an optical lens material is 1.
It is concentrated in about 3 to 1.4.

On the other hand, as an optical lens material having a relatively small specific gravity, thermoplastic resins such as polystyrene (specific gravity: 1.02), polymethylmethacrylate (specific gravity: 1.20) and polycarbonate (specific gravity: 1.19) are known. Has been.
However, these optical lens materials are unsatisfactory in various properties such as heat resistance, solvent resistance, and mechanical strength, and development of an optical lens material having both high crosslink density and low specific gravity is strongly desired. There is.

[0005]

As described above, conventionally, a synthetic resin lens having high crosslink density and excellent physical properties such as low specific gravity and good optical properties is known. Absent. The present invention has been made based on such circumstances, and its purpose is to:
An object of the present invention is to provide an optical lens made of a crosslinked copolymer having a high crosslink density, excellent heat resistance, solvent resistance, and the like, and having excellent physical properties such as low specific gravity and good optical properties.

[0006]

The optical lens of the present invention comprises:
1,12-stearyl dimethacrylate or 1,12-
Stearyl diacrylate (A component) 50 to 90% by weight
And a monomer composition containing 10 to 50% by weight of a monomer (component B) represented by the following chemical formula 2 in a proportion of at least 80% by weight. And a cross-linked copolymer.

[0007]

[Chemical 2] (In Chemical Formula 2, R represents an alkyl group having 6 to 22 carbon atoms, X
Represents a hydrogen atom or a methyl group. )

The present invention will be described in detail below. The optical lens of the present invention comprises a cross-linked copolymer,
The crosslinked copolymer contains a mixed monomer composed of a component A which is a specific crosslinkable monomer and a component B which is a specific acrylate-based monomer as an essential monomer component. It is obtained by copolymerizing a monomer composition.

<Component A> The component A constituting the cross-linked copolymer by the copolymerization reaction is 1,12-stearyl dimethacrylate or 1,12-stearyl diacrylate (hereinafter referred to as “1,12-stearyl di (meth)”). Acrylate "
Also called. ).

Since the 1,12-stearyl di (meth) acrylate as the component A has two radically polymerizable unsaturated double bonds in the molecule, a copolymer obtained by using it. Has a strong three-dimensional crosslinked structure.
As a result, the copolymer, that is, the cross-linked copolymer that constitutes the optical lens of the present invention, has excellent heat resistance and organic solvent resistance, and good polishing characteristics. Further, there is an A component 1,12 Suteariruji (meth) acrylate, alkylene group [- (CH _{2) 12} -] consisting a relatively long main chain consisting of an alkyl group (-C ₆ HH ₁₃₎ side Since it has a structure in which chains are bound, its molecular volume is large. Therefore, this 1,12-stearyl di (meth) acrylate greatly contributes to lowering the specific gravity of the obtained crosslinked copolymer, as compared with the linear diacrylate compound.

<Component B> The component B constituting the cross-linked copolymer by the copolymerization reaction is the alkyl acrylate or alkyl methacrylate (hereinafter, also referred to as "alkyl (meth) acrylate") represented by the above chemical formula 2.

In the chemical formula 2 representing the alkyl (meth) acrylate as the component B, the carbon number of the alkyl group R is importantly related to the physical properties of the resulting crosslinked copolymer. Has 6 to 22 carbon atoms. When the number of carbon atoms in the alkyl group R is less than 6, the resulting crosslinked copolymer cannot achieve a low specific gravity of 1.10 or less. On the other hand, the alkyl group R has 2 carbon atoms.
When it exceeds 2, the optical lens made of the obtained cross-linked copolymer has poor heat resistance and is not practical. Thus, as long as the alkyl group R has an alkyl (meth) acrylate whose carbon number is within the range of 6 to 22, various ones may be selected and used as the B component depending on the intended use of the optical lens. it can.

Specific examples of the alkyl (meth) acrylate represented by Chemical formula 2 include n-hexyl acrylate and n-hexyl acrylate.
-Hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-lauryl acrylate, n-lauryl methacrylate, n-cetyl acrylate, n-cetyl Methacrylate, n-stearyl acrylate, n-stearyl methacrylate, isostearyl acrylate, isostearyl methacrylate, isodecyl acrylate, isodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, behenyl acrylate, behenyl methacrylate and the like can be mentioned. They may be used alone or in combination of two or more.

<Composition ratio of component A and component B> A or more
The component and the component B constitute a mixed monomer which is an essential monomer component. As the composition ratio of the A component and the B component in the mixed monomer, the ratio of [A component: B component (weight ratio)] is 50:50 to 90:10, preferably 55:45 to 85:15. The ratio is If the proportion of the component A in the mixed monomer exceeds 90% by weight, the crosslink density of the obtained crosslinked copolymer becomes too high, and the optical lens becomes brittle and easily broken. On the other hand, when the proportion of the component A is less than 50% by weight, the crosslinking becomes insufficient and the heat resistance and solvent resistance of the optical lens become poor.

<Component C> The monomer composition used for obtaining the cross-linked copolymer contains the above-mentioned mixed monomers as an essential component, but is an optional component constituting the monomer composition. As the above, a copolymerizable monomer (component C) that can be copolymerized with each component constituting the mixed monomer may be contained. It is also possible to adjust the refractive index, dyeability, surface characteristics and the like of the obtained optical lens by the C component. For example, when a hard coat layer is formed on the surface of an optical lens, by using a copolymerizable monomer having excellent compatibility with the hard coat layer as the C component, the adhesion with the hard coat layer is improved. be able to. Further, the viscosity of the monomer composition can be adjusted by the component C to improve the injection property into the polymerization type.

Specific examples of the copolymerizable monomer (component C) include acrylic acid, methacrylic acid, β-methacryloyloxyethyl hydrogen phthalate, β-acryloyloxyethyl hydrogen phthalate, and β-methacryloyloxyethyl hydrogen succinate. Carboxylic acid group-containing monomers such as nates, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyl-acryloxy-3-methacryloxypropane, 3-chloro-2-hydroxypropylmethacrylate and other hydroxyl-containing monomers , Styrene, α-methylstyrene, 4-methylstyrene, 4-methoxystyrene, 4-
Chlorostyrene, 4-hydroxymethylstyrene, 2-
Aromatic vinyl compounds such as ethylstyrene, 4-ethylstyrene, 4-bromostyrene, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-
Examples thereof include polyfunctional (meth) acrylates such as bis [4- (acryloxyethoxy) phenyl] propane, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, ditrimethylolpropane tetraacrylate, and ditrimethylolpropane tetramethacrylate. Is alone or 2
It is also possible to use a mixture of two or more species.

The proportion of this C component in the monomer composition is within the range not departing from the gist of the present invention, and specifically within the range of 0 to 20% by weight of the monomer composition. When the ratio of the C component exceeds 20% by weight, that is, when the ratio of the mixed monomer which is an essential component is less than 80% by weight, the specific gravity is kept at 1.10 or less and various performances are excellent. The objective of the invention of obtaining an optical lens cannot be achieved.

The copolymerization reaction of the mixed monomer composed of the components A and B, or the copolymerization reaction of the monomer composition composed of the mixed monomer and the component C is carried out by an ordinary radical polymerization initiator. To do. Therefore, the polymerization method and reaction conditions for these copolymerization reactions may be the same as in the case of a normal radical polymerization reaction. However, since 1,12-stearyl di (meth) acrylate used as the component A is a bifunctional monomer, the crosslinking reaction proceeds,
As a result, it is virtually impossible to carry out a treatment that involves dissolution or melting of the crosslinked copolymer that is formed.Therefore, use the cast polymerization method that directly gives the desired shape as an optical lens. Is preferred.

The cast polymerization method is a well-known technique, and can be directly applied to the present invention. As the casting polymerization container, plate-shaped, lens-shaped, cylindrical, prismatic, conical, spherical,
Other molds or molds and other containers designed according to the purpose or use are used. The material can be selected from inorganic glass, plastic, metal, and any other material depending on the purpose. The actual polymerization reaction can be carried out by charging a mixture of a monomer composition having a mixed monomer as an essential component and a polymerization initiator into a casting polymerization vessel and heating the mixture. It is also possible to carry out the reaction by previously reacting the monomer composition to a certain extent using another reaction vessel, and adding the prepolymer or syrup having an increased viscosity to the casting polymerization vessel to complete the polymerization. The required amount of the monomer composition and the polymerization initiator may be mixed all at once or may be mixed stepwise. The monomer composition contains antistatic agents, colorants, fillers, UV absorbers, heat stabilizers, antioxidants, and other auxiliary materials, depending on the intended use of the resulting copolymer. Can be made

[0020]

The crosslinked copolymer according to the optical lens of the present invention is obtained by copolymerizing a monomer composition containing a mixed monomer as an essential component. 1,12-stearyl di (meth) acrylate (component A) which is a polymerizable monomer, and a specific alkyl (meth) acrylate (component B) are contained in a specific ratio. Therefore, the optical lens of the present invention has a high crosslink density, is excellent in heat resistance and solvent resistance, and has an extremely low specific gravity of 1.10 or less, as is clear from Examples described later, and further, is excellent. It also has excellent optical characteristics.

The optical lens of the present invention is characterized in that the cross-linked copolymer constituting the optical lens is obtained from the specific monomer composition as described above. Therefore, in order to obtain an actual optical lens by using the crosslinked copolymer, conventionally used means can be applied. That is, means for directly obtaining an optical lens having a specific shape by the casting polymerization method, means for cutting out an optical lens having a desired shape from a plate-shaped body or a lump, and the like can be used. This optical lens, if necessary,
Surface polishing treatment, antistatic treatment, and other post-treatments can be performed, whereby an optical lens having desired performance can be obtained. Furthermore, in order to increase the surface hardness of the optical lens, it is possible to coat the surface with an appropriate inorganic material or an organic coating agent by dipping or the like.

[0022]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to these. In the following examples and comparative examples, "part" means "part by weight". Further, the amount of polymerization charged is shown as a pure content unless otherwise specified.

The various properties of the optical lenses obtained in the respective examples and comparative examples were evaluated as follows. (1) Transparency: Measurement of visible light transmittance based on JIS K7105. (2) Refractive index, Abbe number: Measured using an Abbe refractometer at a temperature of 20 ° C. (3) Specific gravity: The weight M of the lens and the weight w in water are measured,
It was calculated by calculation [M / (Mw)]. (4) Surface hardness: Measurement of pencil hardness based on JIS K5400. (5) Heat resistance: Measurement of the temperature (penetration temperature) at which the penetration is 0.4 mm according to JIS K7206. (6) Organic solvent resistance: The lens was immersed in each of acetone and benzene, and after 24 hours, the appearance was visually observed.

<Example 1> 80 parts of 1,12-stearyl dimethacrylate (component A), 15 parts of n-stearyl methacrylate (component B), and 5 parts of cetyl methacrylate (component B) were mixed to prepare a single mixture. A monomer composition comprising a monomer was prepared, and 1.2 parts of tert-butyl peroxyneodecanoate was added to the monomer composition and mixed sufficiently. This mixed solution is poured into a glass lens mold, which is then heated at 50 ° C. for 10 hours and 60 ° C. for 8 hours.
Polymerization was completed by sequentially heating at 0 ° C. for 3 hours and 100 ° C. for 2 hours at different temperatures, thereby producing a -2.00 diopter colorless and transparent lens. This lens is
The visible light transmittance was 92%, the refractive index was 1.4938, the Abbe number was 50.7, and the specific gravity was 0.994, which was extremely small. The surface hardness of this lens is 3H,
The penetration temperature was 94 ° C., and it was completely insoluble in acetone and benzene and had a high resistance to organic solvents.

Example 2 66.4 parts of 1,12-stearyl diacrylate (component A), 12.45 parts of n-stearyl acrylate (component B), and 4.15 parts of cetyl acrylate (component B). , 10 parts of isostearyl methacrylate (B component), 2 parts of styrene (C component),
Polymerization was performed in the same manner as in Example 1 except that 5 parts of α-methylstyrene (C component) was sufficiently mixed to prepare a monomer composition, and a colorless and transparent lens of -4.25 diopter was obtained. Manufactured. This lens has a visible light transmittance of 91.
3%, refractive index 1.4992, Abbe number 53,
The specific gravity was 0.997, which was extremely small. Also,
The surface hardness of this lens was 2H, and the penetration temperature was 82 ° C. Further, it was completely insoluble in acetone and benzene and had a high resistance to organic solvents.

<Example 3> 56 parts of 1,12-stearyl dimethacrylate (A component), 10.5 parts of n-stearyl methacrylate (B component), 3.5 parts of cetyl methacrylate (B component), and 15 parts of stearyl methacrylate (B component) and α-methylstyrene (C component)
Polymerization was carried out in the same manner as in Example 1 except that 8 parts and 7 parts of ditrimethylolpropane tetraacrylate (C component) were sufficiently mixed to prepare a monomer composition, and +
A 3.00 diopter colorless transparent lens was produced. This lens has a visible light transmittance of 91% and a refractive index of 1.5.
No. 02, the Abbe number was 55.3, and the specific gravity was 1.015, which was sufficiently small. Further, the surface hardness of this lens was 2H, the penetration temperature was 92.5 ° C, and it was completely insoluble in acetone and benzene and had a high resistance to organic solvents.

<Example 4> 47 parts of 1,12-stearyl dimethacrylate (component A), 45 parts of lauryl methacrylate (component B) and 8 parts of pentaerythritol tetraacrylate (component C) were thoroughly mixed. Polymerization was carried out in the same manner as in Example 1 except that the monomer composition was prepared to produce a +1.00 diopter colorless and transparent lens. This lens has a visible light transmittance of 91.4%, a refractive index of 1.494, an Abbe number of 52, and a specific gravity of 1.
It was sufficiently small as 010. Further, the surface hardness of this lens was 2H, the penetration temperature was 88 ° C, and it was completely insoluble in acetone and benzene and had a high resistance to organic solvents.

<Example 5> 66 parts of 1,12-stearyl dimethacrylate (component A), 24 parts of lauryl methacrylate (component B), 2,2-bis [4- (methacryloxyethoxy) phenyl] propane ( Polymerization was carried out in the same manner as in Example 1 except that 5 parts of C component) and 5 parts of α-methylstyrene (C component) were sufficiently mixed to prepare a monomer composition, and -3.75 was obtained. Diopter colorless and transparent lenses were produced. This lens has a visible light transmittance of 9
The refractive index was 1.2%, the refractive index was 1.506, the Abbe number was 52, and the specific gravity was 1.04, which was sufficiently small. The surface hardness of this lens was 2H, the penetration temperature was 90 ° C., and it was completely insoluble in acetone and benzene, and had a high resistance to organic solvents.

<Example 6> 70 parts of 1,12-stearyl dimethacrylate (component A), 23 parts of behenyl methacrylate (component B), 2 parts of styrene (component C), α
Polymerization was carried out in the same manner as in Example 1 except that 5 parts of methylstyrene (component C) was thoroughly mixed to prepare a monomer composition, and a colorless and transparent lens of -4.00 diopter was produced. did. This lens has a visible light transmittance of 91.2.
%, The refractive index was 1.4982, the Abbe number was 55, and the specific gravity was 0.995, which was extremely small. The surface hardness of this lens is 2H, and the penetration temperature is 80 ° C.
Further, it was completely insoluble in acetone and benzene and had a high resistance to organic solvents.

<Example 7> 47 parts of 1,12-stearyl dimethacrylate (component A), 45 parts of n-hexyl methacrylate (component B), and 8 parts of pentaerythritol tetraacrylate (component C) were thoroughly mixed. Polymerization was carried out in the same manner as in Example 1 except that the monomer composition was prepared in the above manner to produce a colorless and transparent lens of +1.50 diopter. This lens has a visible light transmittance of 91%, a refractive index of 1.498, an Abbe number of 52, and a specific gravity of 1.
It was sufficiently small as 033. The surface hardness of this lens was 2H, the penetration temperature was 90 ° C., and it was completely insoluble in acetone and benzene, and had a high resistance to organic solvents.

As described above, the cross-linked copolymers according to each lens of Examples 1 to 7 have excellent optical characteristics, good physical characteristics of low specific gravity, good mechanical strength, heat resistance and It is understood that it has a good balance with a high cross-linking density that exhibits organic solvent resistance, and is extremely preferable as an optical lens.

Comparative Example 1 40 parts of 1,12-stearyl dimethacrylate (A component), 7.5 parts of n-stearyl methacrylate (B component), 2.5 parts of cetyl methacrylate (B component), iso- A lens was produced by polymerizing in the same manner as in Example 1 except that 50 parts of stearyl methacrylate (component B) was mixed to prepare a monomer composition. This lens is transparent and has a specific gravity of 0.96
It was 4 which was extremely small. However, this lens is flexible so that it can be easily deformed by the force of a finger at room temperature, and has a penetration temperature of 50 ° C. or lower, and its heat resistance is considerably small, so that it cannot be used. It is understood that this is because the ratio of the component A in the mixed monomer was too low.

<Comparative Example 2> 94 parts of 1,12-stearyl dimethacrylate (component A), 4.5 parts of n-stearyl methacrylate (component B) and 1.5 parts of cetyl methacrylate (component B) were mixed. Polymerization was carried out in the same manner as in Example 1 except that the monomer composition was prepared to prepare a lens. This lens is transparent and has a refractive index of 1.
It was 4976. The specific gravity was 1.008, which was sufficiently small. But this lens is very fragile,
When dropped from a height of 50 cm, the lens crushed, and when the "edge" was polished, the lens cracked, resulting in lack of practical strength. It is understood that this is because the ratio of the component A in the mixed monomer was too high and the crosslink density was too high.

<Comparative Example 3> 47 parts of 1,12-stearyl dimethacrylate (component A), 45 parts of methyl methacrylate, and 8 parts of pentaerythritol tetraacrylate (component C) were sufficiently mixed to form a monomer composition. Polymerization was performed in the same manner as in Example 1 except that the product was prepared.
A 1.00 diopter colorless transparent lens was produced. This lens had a refractive index of 1.494. However, the specific gravity of this lens is as large as 1.108, which does not satisfy the object of the present invention. It is understood that this is because methyl methacrylate in which the carbon number of the alkyl group R in the above Chemical Formula 2 is 1 was used.

<Comparative Example 4> 40 parts of 1,12-stearyl dimethacrylate (component A), 15 parts of lauryl methacrylate (component B), 2,2-bis [4- (methacryloxyethoxy) phenyl] propane ( (C component) 40 parts and α-methylstyrene (C component) 5 parts were sufficiently mixed to prepare a monomer composition, and polymerization was performed in the same manner as in Example 1 to produce a lens. .. This lens was transparent and had a refractive index of 1.526. However, the specific gravity of this lens is as large as 1.142, which does not satisfy the object of the present invention. This is because the proportion of the mixed monomer (A component and B component) which is an essential component is 80
It is understood that this is because it was less than wt%.

<Comparative Example 5> 80 parts of 1,12-dodecyl diacrylate, 15 parts of n-stearyl methacrylate (component B), and 5 parts of cetyl methacrylate (component B) were mixed to prepare a monomer composition. Example 1 except that it was prepared
Polymerization was performed in the same manner as in 1. to produce a lens. The specific gravity of this lens was as large as 1.102, which did not satisfy the object of the present invention. It is understood that this is because a linear diacrylate compound having no side chain was used in place of the component A.

[0037]

As described above, the optical lens of the present invention is
It has a high degree of colorless transparency and satisfies suitable optical characteristics required for an optical lens. Further, the cross-linked copolymer constituting the optical lens has a very small specific gravity of 1.10 or less and has a high degree of cross-linking structure, and has physical properties such as surface hardness, heat resistance and solvent resistance. Is also excellent and has a very good performance balance.

Claims (1)

[Claims] 1. 1,12-stearyl dimethacrylate or 1,12-stearyl diacrylate (component A) 5
0 to 90% by weight and 10 to 50% by weight of the monomer (component B) represented by the following chemical formula 1.
An optical lens comprising a cross-linked copolymer obtained by copolymerizing a monomer composition containing a mixed monomer of at least 80% by weight. [Chemical 1] (In Chemical Formula 1, R represents an alkyl group having 6 to 22 carbon atoms, X
Represents a hydrogen atom or a methyl group. )