JPH04126710A - Optical material having low specific gravity and excellent impact resistance, optical molded article using the same material and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title optical material having high transparency, heat resistance and refractive index by casting a mixture of a bifunctional (meth) acrylate, an aromatic vinyl and a comonomer together with a radical polymerization initiator to a mold, gradually raising temperature, polymerizing and curing. CONSTITUTION:The objective optical material having low density and excellent impact strength, comprising a resin obtained by subjecting a polymerizable monomer mixture composed of (A) 30-80wt.% one or more of bifunctional (meth) acrylates (e.g. tetramethylene glycol dimethacrylate) shown by the formula (R<1>, R<2> and R<4> are H or CH3; n is 3-18 integer), (B) 20-70wt.% one or more aromatic vinyl monomers (e.g. styrene) and (C) 0-50wt.% one or more of polymerizable monomer (e.g. methyl methacrylate) having a polymerizable double bond and >=98 molecular weight and a polymerizable oligomer to radical polymerization.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention provides an optical material that is excellent in transparency, heat resistance, and impact resistance, has a low specific gravity, is lightweight, and provides a molded article with a high refractive index; The present invention relates to optical molded bodies using the optical material and methods for producing them. The optical molded article of the present invention can be used for various lenses used in optical equipment, eyeglasses, etc.
It is useful as a prism, optical waveguide, disk substrate, etc.

[Prior Art] Materials used to manufacture optical components such as lenses, prisms, optical waveguides, and disk substrates need to be colorless and transparent, but they also need to be lightweight, impact resistant, and moldable. It is attracting attention as a material that can replace inorganic optical materials such as transparent synthetic resins because of its good processability and dyeability.

Transparent synthetic resins used as optical materials are required to have various other properties in addition to those listed above, but refractive index is extremely important.For example, in the case of lenses, transparent synthetic resins with a high refractive index are Their use allows the lens to be thinner to achieve the same focal length than when using low-index materials, thereby reducing the space occupied by the lens in the optical assembly. This has the advantage of reducing the weight and size of the optical device. In addition, transparent synthetic resins have superior impact strength compared to inorganic optical materials such as glass, so
It can also be said to have excellent durability.

By the way, as resins used as optical materials such as plastic lenses, diethylene glycol bisallyl carbonate resin, polymethyl methacrylate, polycarbonate, etc. are generally known, but diethylene glycol bisallyl carbonate resin and polymethyl methacrylate have a low refractive index. is as small as 1.49 to 1.50, so when these resins are molded into plastic lenses, they have the disadvantage that the center thickness, edge thickness, and curvature become larger than inorganic optical glass lenses. Further, although polycarbonate has a high refractive index of 1.58 to 1659, it tends to generate birefringence during molding, and has drawbacks in optical uniformity. Furthermore, since polymethyl methacrylate and polycarbonate are thermoplastic resins with a non-crosslinked structure, the resin fuses during cutting and polishing, and is used in fields that require such processing, such as lenses for precision optical equipment. , it cannot be said that it is a preferable material for optical elements or eyeglass lenses.

In order to improve the above-mentioned drawbacks of thermoplastic resins, it is also known to use ethylene glycol dimethacrylate as a crosslinking agent to create a resin with a crosslinked structure (Japanese Patent Application Laid-Open No. 49-64691). The structural resin has poor impact resistance.

In addition, a method for producing a crosslinked resin using trimethylolpropane tri(meth)acrylate (Japanese Unexamined Patent Publication No. 63
-291841), but this resin material is made by dispersing and curing a genuine metal oxide and has poor transparency, so it cannot be used as an optical material.

Furthermore, JP-A-62-34102 discloses the use of a styrene derivative in which the aromatic ring is substituted with a halogen as a high refractive index component, but when a halogen-substituted styrene derivative is used, it It has the drawbacks of increased specific gravity and poor weather resistance.

In addition, in order to improve the above-mentioned drawbacks, optical materials such as plastic lenses for eyeglasses and optical molded bodies using resins with high refractive index have been developed. When manufacturing optical molded objects such as plastic lenses using high refractive index resin, halogen atoms such as chlorine and bromine atoms; nitrogen atom-containing components such as urethane; sulfur atom-containing components such as thiol; or aromatic rings. A cast polymerization method has been adopted in which a polymerizable component having in the molecule, such as a vinyl monomer, a prepolymer, or a (polymerized) polymer, is injected into a mold and polymerized.

However, the method of producing an optical molded article with a high refractive index by cast-polymerizing the above-mentioned polymerizable components has a lower molding yield than when allyl carbonate or the like is used as a raw material. In general, polymerizable components such as those described above have the disadvantage that polymerization is difficult to control compared to allyl carbonate, and that distortion remains in the optically molded article and adhesion to the mold is insufficient, resulting in peeling from the mold.

[Problems to be Solved by the Invention] The present invention has been made by focusing on the problems of the prior art as described above, and its purpose is to achieve excellent transparency, heat resistance, impact resistance, and low specific gravity. The objective is to provide a novel optical material that is lightweight, has a high refractive index, and has excellent optical properties. Another object of the present invention is to provide an optical molded article made of the above-mentioned optical material and having excellent transparency, heat resistance, impact resistance, and optical properties. Still another object of the present invention is to provide a method for efficiently producing the above-mentioned optical materials and optical molded bodies.

[Means for Solving the Problems] The optical material of the present invention that has achieved the above problems includes (A) one or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers = 20
~70% by weight (C) A polymerizable monomer mixture consisting of 20 to 50% by weight of one or more polymerizable monomers or polymerizable oligomers having a polymerizable double bond and having a molecular weight of 98 or more is radicalized. Copolymerized, with the general formula % formula % () [wherein R1, R2 and R3 are each independently H or C
H3, and n is an integer from 3 to 18].

Alternatively, the above components (A), (B), and (C) can be combined with the following components FD) or (E) (D) in the molecule selected from the group consisting of an alkoxysilyl group, an epoxy group, an alcoholic hydroxyl group, and a carboxyl group. A polymerizable monomer or oligomer having at least one functional group and a radically polymerizable type 2 bond.
Species or two or more: the above components (A), (B),
0.0001 to 30 per 100 parts by weight of (C)
Weight part (E) At least 1ff of alkoxysilyl group, epoxy group, alcoholic hydroxyl group, or carboxyl group in the molecule
One or more compounds having 1 and no polymerizable double bond: the above components (^), (B), (C
) is obtained by radical copolymerization in the presence of 0.0001 to 30 parts by weight based on a total of 100 parts by weight.

Further, the optical molded article of the present invention includes the above components (A), (B
) and (C) into a mold together with a radical polymerization initiator, or the above component (A)
, (B), (c) above component (0) or (E
) and a radical polymerization initiator into a mold, and
Polymerization was started at 0°C, and the temperature increased to 90 to 140% over 8 to 48 hours.
It can be obtained by polymerizing and curing by gradually raising the temperature to ℃.

[Function] The component (A) used in the present invention has the above-mentioned general formula (
There is no particular restriction as long as it is shown in A), for example,
Triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, tetradecaethylene glycol di(meth)acrylate, nonabrobylene glycol di(meth)acrylate, etc. These can be used alone or in combination of two or more.

This component (^) imparts a cross-linked structure to the optical material to increase its heat resistance, prevents fusion and clogging during cutting and polishing, and prevents resin materials from adhering to processing tools.
Furthermore, it is used to impart excellent impact resistance to the obtained optical molded article, and in order to express such characteristics, n in the general formula (A) is 3 to 18.
must be used. Is it resistant to those with n less than 3? The effect of imparting rIS properties is insufficient, and on the other hand, if it exceeds 18, heat resistance cannot be sufficiently increased.

In addition, when m pieces of two or more types of this component (A) are used together, the r molar average (N) defined by the following formula is 3.2
-10 is preferred.

If N is less than 3.2, it is difficult to obtain sufficient impact resistance, while if it exceeds 10, the effect of improving heat resistance will be insufficient.

This component (A) is composed of components (A), (B), (C
) is used in an amount of 30 to 80% by weight based on the total amount.

If the amount is less than 30% by weight, the crosslinking density of the resulting optical material will be small, and the effect of improving heat resistance, cutting workability, beading workability, impact resistance, etc. will be insufficient, while if the amount exceeds 80% by weight, The refractive index of the optical material obtained becomes small, and the polymerized and cured product becomes soft, resulting in poor shape retention. A more preferred amount of component (^) is in the range of 35 to 70% by weight.

Component (B) used in the present invention includes styrene and various styrene derivatives, but in order to obtain an optical material with low specific gravity and excellent weather resistance, a styrene conductor without halogen substitution is desirable and preferred. Examples include styrene, α-methylstyrene, and divinylbenzene. Among them, styrene, α-
It is methylstyrene.

Component (8) functions to impart a high refractive index to the obtained optical material and optical molded article, and in order to effectively express this effect, component (B) must be combined with component (A).
, (B), 20 to 7 in the total amount of (C)
It must be used in a range of 0% by weight.

If it is less than 20% by weight, its contribution to the change in the refractive index of the resulting optical material is small, while if it exceeds 70% by weight, the amount of component (A) used will not reach the specified amount, and the resulting optical molded article will have a small contribution. The crosslinking density decreases, making it impossible to ensure the effects of improving heat resistance, cutting workability, beading workability, impact resistance, and the like. A more preferable amount of component (B) is in the range of 25 to 60% by weight.

The polymerizable monomer component serving as a raw material for the optical material and optical molded article according to the present invention may consist only of the above components (A) and (B), but other physical properties may be added as necessary. Other components (C) may be used as copolymerization components for the purpose of There are no particular restrictions as long as the ingredients are above (
Polymerizable polymers collectively referred to as monofunctional monomers and polyfunctional oligomers that do not fall under A) and component (B) can be used. Specific examples of such component (C) include methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 4=t-butylcyclohexyl methacrylate, 2,3-dibromopropyl methacrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-methacryloyloxymethylthiophene, 3-methacryloyloxymethylthiophene, 2-(2-methacryloyloxyethyl)thiophene, 2-tricyclo[5,2,1,0”
6-3-decenyloxyethyl methacrylate, methyl-2-chloroacrylate, methyl-2-bromoacrylate, cyclohexyl-2-chloroacrylate,
Monofunctional (meth)acrylates such as cyclohexyl-2-bromoacrylate, 2-tricyclo[5,2,1,02']-3-decenyloxyethyl-2-chloroacrylate; ethylene glycol di(meth)acrylate; ) acrylate, diethylene glycol di(meth)acrylate, 1
．． 3-butylene glycol di(meth)acrylate, 1
．． 4-butylene glycol di(meth)acrylate, 1
．． Polyfunctional (meth)acrylates such as 6-hexanethiol di(meth)acrylate; (meth)allyl benzoate;
Di(meth)allyl phthalate, diethylene glycol bisallyl carbonate, 2,2-bis(4-allyloxycarbonyloxyethoxy-3,5-dibromophenyl)propane, 2,2-bis(4-allyloxy-3,5)
(meth)allyl esters such as -dibromophenyl)propane, allyl carbonates, and allyl ethers; reactive oligomers such as epoxy (meth)acrylates, polyester (meth)acrylates, and urethane (meth)acrylates. Among these, (meth)acrylate monomers are preferred in consideration of copolymerizability, homogeneity of the resulting optical material, heat resistance, etc.

In the present invention, the above-mentioned polymerizable monomer (C) is used to add various properties other than those described above to the resulting optical material, as necessary. In order not to impair the properties, there is a limit to the amount used, and the amount should be kept to 50% by weight or less in the total amount of components (A), (B), and (C). In the present invention, at least one of the above components (C) has a solubility parameter (sp value;
ter) is 8.0 to 9.3 (cat/cm')
It is preferable to use a monofunctional polymerizable monomer which is Component (A) and (B) because the homogeneity of the optical material obtained is improved.

The amount in the total amount of (C) is in the range of 5 to 30% by weight.

Among the above-mentioned component (C), monofunctional (meth)acrylates are used as the above-mentioned component (A) and the above-mentioned component (B) to arbitrarily adjust the refractive index, heat resistance, moldability, etc. of the optical material obtained.
It has a compensating effect. Moreover, while polyfunctional (meth)acrylates have the effect of further increasing the heat resistance of the resulting optical material, they reduce the impact resistance. Therefore, when using polyfunctional (meth)acrylates as component (C),
Considering the overall physical properties of the optical material obtained, component (A),
0.1 to 5 in the total amount of (B) and (C)
It is preferable to use it in a range of 0% by weight, more preferably in a range of 5 to 35% by weight.

In the present invention, by using a polyfunctional (meth)acrylate that satisfies the requirements of the following formula as at least one of the above components (C), the crosslinking density of the polymerized cured product is increased and the heat resistance is further improved. This is preferred because an optical material can be obtained. However, if it is too much, it will become too hard and the impact resistance will deteriorate, so the amount used should be determined by adjusting the amount of ingredients (^), (B),
The amount of (C) in the total amount is preferably suppressed to about 30% by weight or less.

85≦M W / r≦128 where MW is the molecular weight of the polyfunctional (meth)acrylate r is the number of polymerizable functional groups in the polyfunctional (meth)acrylate, and component (C) is the polyfunctional (meth)acrylate described above. The above-mentioned component (A), component (
B) and components other than polyfunctional (meth)acrylate (C
) is preferably used in the amount used as component (A).

The amount of (B) and (C) in the total amount is 30 to 75, respectively.
% by weight, 20-65% by weight and 0-20% by weight.

In addition, (meth)allyl ester, allyl carbonate,
Allyl ethers are useful in suppressing the polymerization reactivity of the polymerizable monomer mixture, and have the effect of increasing the production yield especially in cast polymerization, and are effective as components (A) and (B).
, 0.1 to 30% by weight in the total amount of (C)
, more preferably in an amount of 0.5 to 20% by weight, the effect can be effectively exhibited. Furthermore, among component (C), reactive oligomers such as polyester (meth)acrylate and urethane (meth)acrylate have the effect of moderating the shrinkage rate during polymerization, and are effective in increasing the production yield in cast polymerization. Yes, components (A) and (B)
The effect can be effectively exhibited by using (C) in an amount of 1 to 35% by weight, more preferably 5 to 30% by weight, based on the total amount.

It is also possible to use acrylonitrile or methacrylonitrile as this component (C), but these have a molecular weight of less than 98 and a low boiling point, so they boil during cast polymerization as described below and will not enter the optical material. In the present invention, materials with a molecular weight of 98 or less should not be used because they may cause vacancy defects.

The optical material of the present invention contains the above-mentioned component (^) and component (B
) as an essential component, and is obtained by radical polymerization of a polymerizable monomer mixture containing component (C) as required.

Then, when a polymerization initiator is added to the polymerizable monomer mixture having the above-described specific composition and cast polymerization is performed, an optical molded article is obtained by polymerizing and curing within the mold.

By the way, in general, polymerization of monomer components including vinyl monomers is more difficult to control than in the case of polymerizing allyl compounds.This is because the heat generated by polymerization is large, and the polymerization progresses in a short period of time. If too much, the optical properties as a lens etc. may not be satisfied, and problems are particularly likely to occur due to internal distortion during polymerization and incomplete transfer due to peeling from the molded surface of the lens etc. It is.

However, these components (A), (B), (C
), a polymerizable monomer (D) having a polymerizable double bond and at least one of an alkoxysilyl group, an epoxy group, an alcoholic hydroxyl group, and a carboxyl group in the molecule.
Hereinafter, a polymerizable monomer having an alkoxysilyl group is a component (Ds), a polymerizable monomer having an epoxy group is a component (Ds), and a polymerizable monomer having an epoxy group is a component (Ds).
i), the polymerizable monomer having an alcoholic hydroxyl group may be referred to as component (DA), and the polymerizable monomer having a carboxyl group may be referred to as component (Da)],
0.0 for the total weight of (B) and (C).
When 0,001 to 30 parts by weight are used, the adhesion between the mold and the optical molded article is improved, the molding accuracy of the optical molded article is increased, and the molding yield can be improved. In particular, the component (Dg) having an alkoxysilyl group exhibits the above-mentioned effects significantly when a glass mold is used, and even a small amount of addition can improve the adhesion between the mold and the optical material.

The component having an alkoxysilyl group used here (I
lg, ) is a general term for those that have a radically polymerizable double bond in the molecule among those generally known as silane coupling agents, such as 3-methacryloyloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc. , and polymerizable silane coupling agents such as vinyltriethoxysilane.

The alkoxysilyl group-containing component (Ds) is effective when used in an amount of 0.0001 parts by weight or more based on the total of 100 parts by weight of the components (A), (B), and (C). If the amount is too large, the adhesion of the optical material to the mold will become too strong and release from the mold will become difficult, so it is preferable to limit the amount to 0.5 part by weight or less.

A more preferable amount of the component (O5) having an alkoxysilyl group is in the range of 0.001 to 0.2 parts by weight.

Further, as a component (DE) having an epoxy group in the molecule, glycidyl (meth)acrylate is exemplified as a typical example. The effect of the component (DE) having an epoxy group is effectively exhibited by blending 0.1 part by weight or more with respect to the total of 100 parts by weight of the components (A), (B), and (C). However, if the amount is too large, the adhesion of the optical material to the mold becomes too strong and it becomes difficult to release the mold, so it is preferable to limit the amount to 20 parts by weight or less. The component (D
A more preferred amount of E) is 1 to 10 parts by weight.

In addition, components with alcoholic hydroxyl groups in the molecule (DA)
It is a compound that has an alcoholic hydroxyl group and a polymerizable double bond in the molecule, such as a (meth)acryloyl group, an allyl group, a vinyl group, etc., and especially a polymerization compound that has a secondary or tertiary alcoholic hydroxyl group. Polymeric monomers are preferred.

Specific examples include allyl alcohol, 2-hydroxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 4-hydroxybutyl (meth)acrylate.
Acrylate, 6-hydroxyhexyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane monoallyl ether, trimethylolpropane diallyl ether Polymerizable monomers having a primary alcoholic hydroxyl group such as; 2-hydroxypropane (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy -3-phenoxypropyl (meth)acrylate, 2-hydroxy-
3-(meth)acryloyloxypropyl (meth)acrylate, 1,2-bis(2-hydroxy-3-(meth)acryloyloxypropoxy)ethane, 1,2-bis(2-hydroxy-3-(meth)acryloyl oxypropoxy)propane, 1,3-bis(2-hydroxy-3-(meth)acryloyloxypropoxy)propane, 2,2-bis[4-(2-hydroxy-3-(meth)acryloyloxypropoxy)-3 Polymerizable monomers having secondary and tertiary alcoholic hydroxyl groups such as , 5-dibromophenyl copropane; and primary and secondary alcoholic monomers such as 2,3-dihydroxypropyl (meth)acrylate.
．． Examples include polymerizable monomers having a tertiary alcoholic hydroxyl group.

The effect of the component (DA) having these alcoholic hydroxyl groups is the sum of the components (A), CB), and (C) 100
It is effective when blended with 0.1 parts by weight or more, but if it is too large, the adhesion between the molded product and the mold becomes too strong and it becomes difficult to release the mold, so it should not exceed 20 parts by weight. It is best to keep it to A more preferable amount of the component (DA) is 1 to 10 parts by weight.

Next, examples of the component (D) having a carboxyl group in the molecule include those having a carboxyl group and a polymerizable double bond, such as a (meth)acryloyl group, an allyl group, a vinyl group, etc. Specific examples thereof include acrylic acid, methacrylic acid, fumaric acid, maleic acid, cinnamic acid, itaconic acid, methaconic acid, citraconic acid, oleic acid, linoleic acid, linolic acid, erucic acid, and the like.

The effects of these carboxyl group-containing components (DC) are as follows:
The total sum of the components (^), (B), and (C) is 100
It is effective when blended with 0.1 parts by weight or more, but if it is too much, the adhesion between the molded product and the mold becomes too strong and it becomes difficult to release the mold, so keep it below 10 parts by weight. Should. A more preferable amount of this component (DC) is in the range of 0.5 to 8 parts by weight.

As mentioned above, in the present invention, the components (A) and (B)
, (C), a polymerizable monomer having an alkoxysilyl group (OS), a polymerizable monomer having an epoxy group (D
), a polymerizable monomer having an alcoholic hydroxyl group (DA
) or a polymerizable monomer having a carboxyl group (DC)
By using , it is possible to improve the adhesion between the molded body and the mold and improve the molding accuracy.

In addition, in the present invention, the above components (Ds), (Dc)
.

A compound (E) having an alkoxysilyl group, an epoxy group, an alcoholic hydroxyl group, or a carboxyl group in the molecule and having no polymerizable double bond as a component for improving adhesion with the mold in place of (DA) and (Dc). [Hereinafter, a compound having an alkoxysilyl group will be referred to as component O:S), a compound having an epoxy group as component (EE), a compound having an alcoholic hydroxyl group as component (EA), and a compound having a carboxyl group as component (Ec). Even when at least one of the following is blended, the same effects as above can be obtained. Specific examples of compounds having such effects include 3-glycidoxyprobyltrimethoxysilane, as the component (E5) having an alkoxysilyl group,
3-glycidoxypropylmethyldimethoxysilane, 2
- Non-polymerizable silane coupling agents such as (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane; As a component (EE) having an epoxy group, ethylene Glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 2.2-bis(4-glycidoxycyclohexyl)propane, 2.2-bis(4-glycidoxyphenyl)propane, 2.2 Components having alcoholic hydroxyl groups (EA ), octatool, polyethylene glycol, benzyl alcohol, S-butyl alcohol, t-butyl alcohol, cyclohexyl alcohol, 4-t-butylcyclohexyl alcohol, 2,2-bis(4-(2-hydroxypropoxy)phenylpropane), etc. , as a component (Ec) having a carboxyl group, valeric acid,
Caproic acid, enanthic acid, Kundecanoic acid, Adipic acid,
Preferred examples include benzoic acid and phthalic acid.

In addition, each component (Es) having these alkoxysilyl group, epoxy group, alcoholic hydroxyl group or carboxyl group
, (EE), (Ea) and (lc) are preferably used in the amounts of the components (Ds), (Dri, (Da
) and (DC) are the same as the ranges and reasons for setting them, respectively.

The raw material components for obtaining the optical material according to the present invention are as described above, but if necessary, adhesion improving aids such as isocyanate compounds may be used in combination with other components, or other known additives, For example, ultraviolet absorbers, antioxidants,
Appropriate amounts of drip-proofing agents, coloring agents, mold release agents, etc. can also be added.

The optical material and optical molded article of the present invention contain the component (A)
and component (B) as essential components, and component (C) as necessary.
or the component (DI) having an alkoxysilyl group, an epoxy group, an alcoholic hydroxyl group, or a carboxyl group in the molecule if necessary.
, (DC), (D- or (Oc), or component (El), (Et), (EA) or (E
It is obtained by reacting a mixture containing c) in the presence of a radical polymerization initiator. The method of radical polymerization is not particularly limited (conventionally well-known methods can be employed, but specific examples include: (1) heating and polymerizing the above mixture in the presence of a radical polymerization initiator; (2) heating the above mixture in the presence of a radical polymerization initiator; Examples include a method of ultraviolet polymerization in the presence of a photosensitizer, and (2) a method of electron beam polymerization of the above mixture.

Method (2) is the most common method, the equipment is simple, and the radical polymerization initiator is relatively inexpensive.

In the case of method (2), the curing speed is fast and the polymerization time can be shortened.

In the method (2), since polymerization can be performed even in the absence of a radical polymerization initiator or a photosensitizer, it is also possible to reduce the amount of impurities mixed into the high refractive index resin.

Specific examples of method (2) include known methods such as bulk polymerization, solution polymerization, and suspension polymerization.

Among these methods, when producing optical molded objects such as lenses, the cast polymerization method is preferable because it can be formed into a desired shape at the same time as the polymerization. An example of this method is to inject a polymer mixture into a glass mold, raise the temperature, and polymerize it. In this case, it is necessary to prevent the cured product from peeling off from the inner surface of the mold due to internal strain during polymerization, resulting in incomplete transfer of the optical surface, and to obtain an optically uniform optical molded product. , polymerization started at 20-60℃ after mold injection, and 8-48℃
It is preferable to gradually raise the temperature to 90 to 140°C over time to advance the polymerization reaction. In particular, if the temperature until the polymerizable monomer mixture gels is kept at a low temperature of 70°C or less and the polymerization reaction is allowed to proceed slowly, internal strain during polymerization can be suppressed, and peeling from the mold surface can be prevented and the optical surface can be The transfer becomes more complete, and a molded article with high optical uniformity can be obtained.

In order to cause gelation at temperatures below about 70°C, it is desirable to select at least one radical polymerization initiator that has a 10-hour half-life temperature of less than 70°C. . Specific examples of low-temperature decomposable radical polymerization initiators that meet such selection criteria include t-butylperoxyneodecanate, t-hexylperoxyneohexanate, t-butylperoxypivalate,
3,5.5-trimethylhexanoyl peroxide,
Peroxide polymerization initiators such as lauroyl peroxide,
and 2.2′-azobis(2,4-dimethylvaleronitrile), 2.2′-azobis(isobutyronitrile)
Preferred examples include azo compound-based polymerization initiators such as , 2,2°-azobis(2-methylbutyronitrile), and the like. Even if the compound itself decomposes at temperatures above 70°C, compounds that substantially decompose at temperatures below 70°C when combined with a reducing agent or a decomposition accelerator can similarly be used as preferred radical polymerization initiators. .

In addition, in order to reduce the amount of residual agglomerates as much as possible at the end of cast polymerization, the temperature at the end of polymerization is set at 90 to 140°C.
and "10" as at least one radical polymerization initiator.
It is desirable to use an initiator with a half-life temperature exceeding 70° C. Such high-temperature decomposable radical polymerization initiators include, for example, t-butylperoxy-2-ethylhexanate, 1. 1-bis(t-butylperoxy)
- A peroxide-based polymerization initiator such as 3,3,5-trimethylcyclohexane, t-butyl peroxylaurate, t-butyl peroxyallyl carbonate, and 1.1'
-Azobis(cyclohexane-1-carbonitrile),
Examples include azo compound-based polymerization initiators such as 1-[(1-cyano-1-methylethyl)azocoformamide.

These radical polymerization initiators are usually used in an amount of 0.01 to 10% by weight, preferably 0.05 to 10% by weight, based on the polymerizable monomer mixture.
It is used in a range of 5% by weight.

Incidentally, as a specific method for producing an optical molded body by cast polymerization, known methods such as an all-cast method and a semi-finish method can be employed, and preferred methods are as follows.

That is, a mixture of the aforementioned raw material components and a radical polymerization initiator (hereinafter referred to as the raw material mixture) is injected into a cavity composed of a glass or metal mold and a resin gasket or adhesive tape. After fixing with a spring-loaded clip or the like if necessary, polymerization is carried out by heating and raising the temperature so as to satisfy the above-mentioned conditions. The material of the resin gasket or adhesive tape is not particularly limited as long as it has sufficient rigidity to maintain the shape of the cavity during injection; It is preferable to use an elastic material in order to alleviate the occurrence of this phenomenon.

Spacer materials called resin gaskets include:
Low density polyethylene, soft polyvinyl chloride, ethylene/
Preferred examples include synthetic resin materials such as vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyolefin elastomer, polyester elastomer, and polyamide elastomer.

In the present invention, the aromatic vinyl monomer (B) is used as one of the polymerizable monomer components as described above, and the aromatic vinyl monomer (B) is a resin constituting the gasket. Plasticizers and low molecular weight components contained therein may be eluted during heat polymerization, making the optical molded object cloudy, or the gasket may swell and a portion of the raw material mixture may leak out, causing shape defects in the optical molded object. Problems arise. Therefore, when performing cast polymerization, before injecting the raw material mixture, the inner surface of the mold (molding surface) is cleaned with an organic solvent such as saturated hydrocarbon, halogenated hydrocarbon, dimethylformamide, etc. to remove dirt and dust from the inner surface of the mold. It is good to remove plasticizers and low molecular weight components near the molding surface in advance.Ultrasonic cleaning is the most effective cleaning method. It is also possible to form a film of thermoplastic polyamide or the like on the inner surface of the mold to prevent elution of plasticizers and low molecular weight components from the mold constituent materials.

The optical molded product obtained in this way has high transparency, excellent heat resistance and impact resistance, and has a low specific gravity and high refractive index, and is suitable for various lenses and prisms used in optical equipment, glasses, etc. It is useful as a leading waveguide, a disk substrate, etc.

[Example] Next, the present invention will be specifically explained with reference to Examples. In the following examples, a plastic lens was selected as the optical molded body.

In addition, the method of evaluating physical properties in the following examples is as follows.

(Appearance) Visually observe the hue, transparency, and optical surface condition of a 1.5 mta thick sheet polymer or plastic lens obtained by cast polymerization, and select one that is colorless, transparent, and in good surface condition.
"Good" was displayed. For other items, their status is described. "Poor r-surface condition" indicates that the polymer (molded body) has peeled off from the molding surface of the mold, resulting in incomplete transfer of the lens surface.

(Refractive index and Abbe number) Measured using an Abbe refractometer according to JIS K7105.

(Total light transmittance) Measurement was performed using a turbidity meter on a sheet-like polymer having a thickness of 15 +u+ obtained by cast polymerization.

(Yield) The percentage of lenses with good optical surface condition among the 20 lenses is shown.

(Cutting workability) The edge portion of the lens was polished using a polishing machine, and the condition was observed. If no cracks, cracks, or fusions were observed, the lens was designated as O.

(Heat resistance) The lens was placed in a hot air dryer at a predetermined temperature for 2 hours, and the presence or absence of deformation such as warp was observed during this time.

Those in which no deformation was observed are marked with an O mark.

(Impact resistance) ＾Evaluated according to STM Fe12. That is, the center thickness T
W (g) hard ball to the lens of c (m intestine)) I (cm)
Drop the lens from a height that will not break the lens (wxi
i)/Tc. In addition, the impact energy at this time was calculated in terms of potential energy and is also displayed. Also r
"FDA Rejected" indicates that the lens was broken when a 16.2g steel ball was dropped from a height of 127CI11 in accordance with ASTM F 659.

Example 1 A polymerizable monomer mixture consisting of 40 parts by weight of tetraethylene glycol dimethacrylate, 10 parts by weight of nonaethylene glycol dimethacrylate, and 50 parts by weight of styrene was
．． 2°-azobis(2°4-dimethylvaleronitrile) 0
．． The raw material mixture to which 1 part by weight was added was poured into a mold consisting of two glass plates and a silicone rubber gasket, held at 50°C for 6 hours, and then heated to 110°C for 16 hours.
The temperature was raised over time to polymerize. The mixture was further held at 110° C. for 2 hours for post-polymerization. The obtained flat optical material was colorless and transparent. Various physical properties of this optical material are shown in Table 342 (1).

Examples 2 to 20 and Comparative Examples 1 to 4 Using polymerizable monomer mixtures having the compositions shown in Table 1 (1) to (3), the same operations as in Example 1 were repeated to produce flat optical materials. Obtained. Table 2 (1) shows the physical properties of these optical materials.
- Shown in (3).

Example 21 2,2°-Azobis (2 , 4-dimethylvaleronitrile) and 2 parts by weight of 2.2-bis(4-glycidoxyphenyl)propane, the same operation as in Example 1 was repeated to form a flat plate. An optical material was obtained. Table 2 (3) shows the physical properties of these optical materials.
It is also shown in .

Example 22 0.2 parts of lauroyl peroxide was added to a polymerizable monomer mixture consisting of 40 parts by weight of tetraethylene glycol dimethacrylate, 50 parts by weight of styrene, 10 parts by weight of nonaethylene glycol dimethacrylate, and 5 parts by weight of methacrylic acid.
Part by weight and 0.1 part by weight of t-butylperoxy-2-ethylhexanoate were added to the raw material mixture, and the inner diameter was 75 mm.
A glass mold designed to obtain a lens with a dioptric power of -3 and an OOD, and a center thickness of 1. F+++m and alcohol soluble polyamide (BASF
It was injected into the cavity of a mold made of a gasket made of a polyolefin elastomer (trade name "Milastomer", manufactured by Mitsui Petrochemical Co., Ltd.) whose inner surface was coated with "Ultraamide IC" (trade name, manufactured by Mitsui Petrochemical Co., Ltd.).

This was kept at 50°C for 4 hours in a constant temperature bath, then gradually heated to 120°C over 15 hours, and then held at 120°C for 30 minutes to perform cast polymerization. By removing the gasket from the polymerization product, a plastic lens with a diameter of 75 mm and a power of -3,00 D was obtained. The optical surface condition of the obtained plastic lens was good, and the various physical properties as a lens were excellent as shown in Table 4 (1).

Examples 23 to 36's3 Plastic lenses were obtained by repeating the same operations as in Example 22 using a polymerizable monomer mixture having the composition shown in Tables (1) and (2), a polymerization initiator, and the following gasket. . The physical properties of the obtained plastic lens are 'tSJ
As shown in Tables (2) and (2), the results were excellent.

Gasket A: A polyolefin elastomer (“Milastomer 1”; manufactured by Mitsui Petrochemical Co., Ltd.) gasket whose inner surface is coated with alcohol-soluble polyamide (“Ultraamide IC”; manufactured by BASF).

Gasket B: Gasket made of ethylene-vinyl acetate copolymer whose inner surface is coated with alcohol-soluble polyamide (“Ultraamide IC”; manufactured by BASF).

Gasket C: A low-density polyethylene (“F-Selen” manufactured by Sumitomo Chemical Co., Ltd.) gasket that was ultrasonically cleaned in n-hebutane for 5 minutes.

Gasket D = untreated ethylene-vinyl acetate copolymer gasket.

Comparative Examples 5 to 9 Using a polymerizable monomer mixture, a polymerization initiator, and a gasket having the compositions shown in Table 3 (1) and (2), Example 2
A comparison lens was obtained by repeating the same operation as in 2. The physical properties of this comparative lens are as shown in Table 4 (1) and (2), and it did not satisfy the physical properties required for a lens.

Table 1 (1) to (3), Table 2 (1) to (3), Table 3 (1), (2) and Table 4 (1), (2) below
) The abbreviations of the compounds shown in ) are as follows.

(A): Bifunctional (meth)acrylate (^) (B): Aromatic vinyl monomer (B) (C): Polymerizable monomers other than (A) and (B) (
C) (DC): Polymerizable monomer having a carboxyl group and a polymerizable double bond in the molecule (Ds): Polymerizable monomer having an alkoxysilyl group and a polymerizable double bond in the molecule (Dt) :Polymerizable monomer (DA) having an epoxy group and a polymerizable double bond in the molecule :Polymerizable monomer additive (E) having an alcoholic hydroxyl group and a polymerizable double bond in the molecule A compound having a carboxyl group, an alkoxysilyl group, an epoxy group, or an alcoholic hydroxyl group and no polymerizable double bond EG: Ethylene glycol dimethacrylate 3EG Cotriethylene glycol dimethacrylate 4EG: Polyethylene glycol non-200 dimethacrylate (Shin Nakamura) 4EG': Polyethylene glycol #200 diacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) 9EG: Polyethylene glycol #400 dimethacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) 9PG: Polybrobylene glycol #400 dimethacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) 14EG: Polyethylene glycol #600 dimethacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) 23EG: Polyethylene glycol 5too.

Dimethacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) St: Styrene α-5t: α-methylstyrene BZMA: Benzyl methacrylate MMA: Methyl methacrylate BG: 1,3-butylene glycol dimethacrylate ADC diethylene glycol bisallyl carbonate MAA: methacrylic acid AA Niacryl Acid MOPS-M: 3-methacryloyloxypropyltrimethoxysilane CPS-M: 3-chloropropyltrimethoxysilane GMA nigericidyl methacrylate GPP: 2,2-bis(4-glycidoxyphenyl)propane HEMA: 2-hydroxyethyl Methacrylate BPPP: 2.2-bis[4-(2-hydroxypropoxy)phenyl]propane 40EM: 1.2-bis(2-hydroxy-3-methacryloyloxyproxy)ethane (manufactured by Kyoeisha Yushi Co., Ltd.) -200PA: ( (manufactured by Kyoeisha Yushi Co., Ltd.) VB2: 2,2°-azobis(2,4-dimethylvaleronitrile) V2O: 2,2'-azobis(isobutyronitrile) V2O: 1,1'-azobis(cyclohexane-1-carbo Nitrile) IPP: Isopropyl peroxydicarbonate LPO: Lauroyl peroxide BEH: t-Butylperoxy-2-ethylhexanoate Table 1 (1) Table 1 (2) Table 2 (2) Table 2 (3) ) [Effects of the Invention] The present invention is constructed as described above, and transparency can be improved by specifying the type of polymerizable monomer to be used or by radical polymerization by adding a compound having a specific functional group. It has now become possible to provide an optical material with excellent impact resistance and heat resistance, low specific gravity, and high refractive index, and an optical molded article made of this optical material. This optical molded body can be used for lenses such as eyeglass lenses and lenses for various optical devices, prisms, optical fibers, etc.
It can be widely used as a member for guiding waveguides, optical disks, etc.

Applicant: Nippon Shokubai Chemical Co., Ltd.

Claims (7)

[Claims] (1) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more types of polymerizable monomers or polymerizable oligomers having a polymerizable double bond and a molecular weight of 98 or more: 0 to 50% by weight. An optical material with low specific gravity and excellent impact resistance characterized by being made of a resin obtained by polymerization. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2 and R^3 each independently represent H or CH_3, and n is an integer from 3 to 18. ) (2) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more polymerizable monomers or polymerizable oligomers having a polymerizable double bond and having a molecular weight of 98 or more: 0 to 50% by weight (D) Alkoxysilyl group in the molecule A polymerizable monomer or oligomer having at least one functional group selected from the group consisting of , epoxy group, alcoholic hydroxyl group, and carboxyl group and a radically polymerizable double bond.
Species or two or more species: characterized by being made of a resin obtained by radical polymerization of 0.0001 to 30 parts by weight per 100 parts by weight of the above components (A), (B), and (C). An optical material with low specific gravity and excellent impact resistance. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2, R^3 and n have the same meanings as above) (3) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more polymerizable monomers or polymerizable oligomers with a molecular weight of 98 or more having a polymerizable double bond: 0 to 50% by weight, (E) Alkoxysilyl in the molecule One or two compounds having at least one of a group, an epoxy group, an alcoholic hydroxyl group, and a carboxyl group and having no polymerizable double bond.
Species or more: Total of the above components (A), (B), and (C) 100
An optical material with low specific gravity and excellent impact resistance, characterized in that it is made of a resin obtained by radical polymerization in the presence of 0.0001 to 30 parts by weight. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2, R^3 and n have the same meanings as above) (4) An optical molded article comprising a molded article of the optical material according to claims (1) to (3). (5) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more polymerizable monomers or polymerizable oligomers having a polymerizable double bond and having a molecular weight of 98 or more: 0 to 50% by weight, together with a radical polymerization initiator. A method for producing an optical molded article, which comprises injecting it into a mold, starting polymerization at 20 to 60°C, and gradually increasing the temperature to 90 to 140°C over 8 to 48 hours to polymerize and harden. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2, R^3 and n have the same meanings as above) (6) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more polymerizable monomers or polymerizable oligomers having a polymerizable double bond and having a molecular weight of 98 or more: 0 to 50% by weight (D) Alkoxysilyl group in the molecule A polymerizable monomer or oligomer having at least one functional group selected from the group consisting of , epoxy group, alcoholic hydroxyl group, and carboxyl group and a radically polymerizable double bond.
Seed or two or more: A mixture consisting of 0.0001 to 30 parts by weight based on 100 parts by weight of the above components (A), (B), and (C) is injected into the mold together with a radical polymerization initiator, A method for producing an optical molded article, which comprises starting polymerization at 20 to 60°C, and gradually increasing the temperature to 90 to 140°C over 8 to 48 hours to polymerize and harden. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2, R^3 and n have the same meanings as above) (7) (A) One or more bifunctional (meth)acrylates represented by the following general formula (A): 30 to 80% by weight (B) One or more aromatic vinyl monomers :20
~70% by weight (C) One or more polymerizable monomers or polymerizable oligomers with a molecular weight of 98 or more having a polymerizable double bond: 0 to 50% by weight, (E) Alkoxysilyl in the molecule One or two compounds having at least one of a group, an epoxy group, an alcoholic hydroxyl group, and a carboxyl group and having no polymerizable double bond.
Species or more: Total of the above components (A), (B), and (C) 100
It is injected into a mold together with 0.0001 to 30 parts by weight and a radical polymerization initiator, and polymerization is started at 20 to 60°C, and the temperature is gradually raised to 90 to 140°C over 8 to 48 hours. A method for producing an optical molded article, which is characterized by polymerizing and curing. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (In the formula, R^1, R^2, R^3 and n have the same meanings as above)