JPH01207307A - Production of resin with high refractive index - Google Patents

Abstract

PURPOSE:To readily produce the title resin, excellent in colorless transparency and useful as a resin for optical materials such as lenses or optical fiber, by radical-polymerizing specified polymerizable monomer(s). CONSTITUTION:A radical polymerization is carried out using a mixture of polymerizable monomers containing one or more polymerizable monomers [e.g., S-methylthio(meth)acrylate] of formula I (R1 is H or CH3; R2 is 1-16C alkyl, halogenated alkyl, alkoxy alkyl, alkyl thioalkyl or heterocyclic substituted alkyl) as an essential component, preferably in an amount of >=15wt.% of the polymerizable monomer components and when needed, other polymerizable monomer(s) with a refractive index of pref. >=1.48 capable of radical copolymerization with said polymerizable monomer(s) (e.g., methyl methacrylate or acrylonitrile) to produce the objective resin with high refractive index (normally >=1.55).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a novel method for producing a high refractive index resin that is colorless and transparent.

BACKGROUND OF THE INVENTION Optical components such as lenses, prisms, and optical waveguides are known in the art. The materials used to manufacture such optical components need to be colorless and transparent. Further, it is desirable that these materials have a high refractive index. In the case of lenses, the use of high-index materials makes it possible to create thin lenses that have the same focal length as thick lenses made from low-index materials. The use of thin lenses has the advantage of reducing the volume of space occupied by the lenses in the optical assembly, making the optical device lighter and smaller. In particular, for eyeglass lenses, high refractive index lens resin made of transparent synthetic resin is used as a material to replace inorganic optical lenses because of its light weight, impact resistance, moldability, and dyeability, making it a popular material for plastic lenses. The field of application is expanding as a result.

Conventionally, as resins used as glass lens materials, noethylene glycol bisallyl carbonate resin, polymethyl methacrylate, polycargonate, etc. are generally used, but noethylene glycol bisallyl carbonate resin Resins and polymethyl methacrylate have a small refractive index of 1.49 to 1.50, so when these resins are molded into glass lenses, the center thickness, edge thickness, and curvature will be larger than inorganic optical glass lenses. There were drawbacks. Furthermore, although polycargonate has a high refractive index of 1.58 to 1.59, it tends to cause birefringence during molding and has a drawback in optical uniformity.

In addition, although vinylnaphthalene and vinyl carbazole provide resins with high refractive index, the resulting resins have large dispersion and significant coloring, and are not satisfactory as optical plastic lens materials.

<Problems to be Solved by the Invention> It is an object of the present invention to provide a method for producing a high refractive index resin that is colorless and transparent and has low decomposition.

Means and Effects for Solving the Problems In view of the current situation, the present inventors have made extensive studies and have developed a radical polymerization initiator using a sulfur-containing polymerizable monomer with a specific structure as an essential component. The present inventors have discovered that a resin obtained by polymerization in the presence of the above problem solves the above-mentioned problems, has a high refractive index, and is excellent in colorless transparency, leading to the completion of the present invention.

That is, the present invention provides a method for producing a high refractive index resin by radical polymerization, in which one or more polymerizable monomers (I) represented by the following general formula (1) are used as essential components, and the necessary A method for producing a high refractive index resin characterized by using a polymerizable monomer component containing the polymerizable monomer (1F and another polymerizable monomer [I[] that can be radically copolymerized with It is.

(Note) General formula (1) % represents an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, an alkylthioalkyl group, or an alkyl group substituted with a heterocycle. ) The polymerizable monomer [1) in the present invention is represented by the above general formula (1) (meth)
Acrylic acid thioester can be used without any restrictions, and can be obtained, for example, by converting a thiol corresponding to the ester moiety into a (meth)acrylic acid ester using a conventional method. For example, a method of dehydrohalogenating a thiol corresponding to the ester moiety and a (meth)acrylic acid halide can be mentioned.

Specific examples of such polymerizable monomer [I] include S-methylthio(meth)acrylate, s-ethylthio(meth)acrylate, 5-n-propylthio(meth)
Acrylate, 5-1-propylthio(meth)acrylate S -n-butylthio(meth)acrylate,
5-see-butylthio(meth)acrylate, 5-t
-Butylthio(meth)acrylate, 5-1-butylthio(meth)acrylate, S-amylthio(meth)acrylate), 5-n-hexylthio(meth)acrylate, S-cyclohexylthio(meth)acrylate%5-
n-octylthio(meth)acrylate, 5-t-nonylthio(meth)acrylate, 5-n-dodecylthio(
meth)acrylate, 5-1-dodecylthio(meth)acrylate, s-hexadecylthio(meth)acrylate, 5-(3-chloropropyl)thio(meth)acrylate, 5-(2-methoxyethyl)thio(meth)acrylate , 5-(2-ethoxyethyl)thio(meth)acryle), 5-(2-furfurylmethyl)thio(meth)
Examples include, but are not limited to, acrylates.

In the production method of the present invention, only one kind or 2ai or more of the polymerizable monomer CD may be used as the polymerizable monomer component, but if necessary, other polymerizable monomers (II) may be copolymerized. May be used as a component. Other polymerizable monomers that can be used [
The ID is not particularly limited as long as it can be lanocal copolymerized with the polymerizable monomer (1), and in addition to monofunctional monomers and polyfunctional monomers, polymerizable polymers collectively called oligomers can be used. The single N@integral refractive index is preferably 1.48 or more.

methacrylate, 4-tert-butylcyclohexyl methacrylate, 2,3-sopromoglovir methacrylate, phenyl acrylate, phenyl methacrylate, pentyl acrylate, be/zyl methacrylate, chlorophenylacrylate, chlorophenyl methacrylate, bromophenyl acrylate, bromophenyl methacrylate , trichlorophenyl acrylate, trichlorophenyl methacrylate, tribromophenyl acrylate, tribromophenyl methacrylate, 2-methacryloyloxymethylthiophene, 3-methacryloyloxymethylthiophene, 2-(2-methacryloyloxyethyl)thiophene, bromo 2-methacryloyloxymethylthio % Nopromo 2-methacryloyloxymethylthiophene, Tripromo 2-methacryloyloxymethylthiophene, 2-Tricyclo[5
,2,1,0214]-3-deJ hyoxyethyl methacrylate, 2-tricyclo(5,2,1,02=' ]
-3-de, celthioethyl methacrylate, 2-tricycloC5,
2,1,02*6]-3,4-nochlorodecyltheoethyl methacrylate, 2-tricyclo[5,2,1,02
ψ6] Monofunctional acrylic normal esters and methacrylic acid esters such as -3,4-dibromodecylthioethyl methacrylate; ethylene glycol dimethacrylate, flopylene glycol dimethacrylate, trimethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, hekite Methylene glycol dimethacrylate, noethylene glycol dimethacrylate, trimethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolgulono9trimethacrylate, 2,2-bis-(4-acryloyloxyphenyl) Propane, 2,2-bis-(4-methacryloyloxyphenyl)propane, 2,2-bis-(4
- methacryloyl oxy7-ethoxyphenyl)furopane,
Bis-(4-methacryloylox7ethoxyphenyl)
Sulfone, 2,2-bis-(3,5-nopromo-4-methacryloyloxyethoxyphenyl)chloroA? N, 2
, 5-bismethacryloyloxymethylthiophene, 2
, 5-bismethacryloyloxymethyl-3,4-nobromothiophene and other polyfunctional acrylic esters and methacrylic esters: methyl-2-chloroacrylate, methyl-2-bromoacrylate, cyclohexyl-2-chloroacrylate, cyclo Hexyl-2-bromoacrylate, 2-tricyclo[5,2,1,02+
' ] -] 3-de! pillow oxyethyl-2-chloroacrylate 2-tricycloC5,2,1,02=6)
-3-deJR thioethyl-2-chloroacrylate, 2
-tricyclo[5,2,1,02+6]-3,4-dibromodecylthioethyl-2-chloroacrylate, etc.
- Halogenoacrylic acid esters; aromatic thioacrylic acid esters and thiomethacrylic acid esters such as phenylthioacrylate, phenylthiomethacrylate, benzylthioacrylate, pennorthiomethacrylate; 1,2-bis((meth)acryloylthio) Polyfunctional thio(meth)acrylic acid esters such as ethane, bis-(2-(meth)acryloylthioethyl)ether, and 1,4-bis((meth)acryloylthiomethyl)benzene; Saturated nitriles; ammonium, allyl sulfate, diallyl phthalate, diethylene glycol bisallyl carbonate, 2.2-
Bis-(4-allyloxycar?nyloxyethoxy-
3,5-dibromophenyl) fo pan, 2,2-bis-
Allyl esters, allyl carbonates, and allyl ethers such as (4-allyloxy-3,5-dibromophenyl)pronobenzene; styrene, chlorostyrene, bromostyrene, dichlorostyrene, dipromostyrene/, methylstyrene, divinylbenzene, etc. Vinyl aromatics; epoxy acrylate, epoxy methacrylate, polyester acrylate, polyester methacrylate, I
urethane acrylate? Reactive oligomers such as urethane methacrylate can be mentioned, and one or more of these can be used.

In the production method of the present invention, the polymerizable monomer [11] is used to obtain a resin with low dispersion and high refractive index.

In order to fully express these characteristics, the amount of polymerizable monomer [13] used is 5' in the polymerizable monomer component! It is preferably ks or more, more preferably 10 weight or more.

If the amount is less than 5% by weight, the contribution of the polymerizable monomer (1) to increasing the refractive index becomes small.

The type and amount of the polymerizable monomer (n) are selected as necessary, taking into consideration the refractive index of the high refractive index resin to be obtained. In order to obtain a resin with a high molecular weight, it is preferable that the amount used is less than 95 parts by weight, more preferably less than 90 parts by weight in the polymerizable monomer components. However, when the high refractive index resin obtained by the production method of the present invention is used for applications such as lenses, polyfunctional (
Monomers with two or more polymerizable unsaturated groups in the molecule, such as meth)acrylic acid esters, are essential for high refractive index resins that have excellent heat resistance, cutting workability, and beading workability. It is preferable in terms of the amount obtained, and the amount thereof can be 5 to 95% by weight, more preferably 10 to 90% by weight, in the polymerizable monomer component.

K more achieved. The method of radical polymerization is not particularly limited, and conventionally well-known methods can be employed, but
Specific examples include: (1) a method of heating and polymerizing a polymerizable monomer component in the presence of a radical polymerization initiator, (2) a method of polymerizing a polymerizable monomer component by ultraviolet light in the presence of a photosensitizer, (2) polymerization. Examples include a method of electron beam polymerization of a monomer component.

Method (2) is the most common method, and 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.

In the case of method (2), the polymerization method is not particularly limited, and conventionally known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used. Among these methods, in the present invention, it is preferable to use bulk polymerization because it is possible to cast a shadow into a desired shape when using heavy metals.For example, bulk polymerization is preferable. Pour into mold and heat to 30~60℃
A specific example is a method in which polymerization is carried out by gradually raising the temperature. Furthermore, by appropriately selecting the type and amount of the polymerization initiator used, a high refractive index resin can also be produced by reaction injection or in-mold molding methods. In cases other than cast polymerization, a step of shading into a desired shape is required after polymerization. Examples of radical polymerization initiators that can be used during polymerization include benzoyl peroxide, acetyl/
Peroxides such as 4'-ogicide, di-t-butyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxy-2-ethylhexanoate, etc.
．． 2'-azobisisobutyronitrile, 2.2'-azobis-(2,4-trimethylvaleronitrile), 1.1
'-7 Sopis (cyclohexane-1-carbonitrile)
and the like, and one or more of these can be used in an amount of 0.0% relative to the polymerizable monomer component.
It can be used in an amount of 1 to 10% by weight, preferably 0.05 to 5% by weight, in combination with an accelerator if necessary.

Polymerization conditions cannot be definitively defined as they are affected by the type of polymerizable monomer components, composition ratio, type of polymerization initiator, etc., but in general, polymerization is started at a relatively low temperature and the temperature is slowly increased. It is preferable to use a polymerization method in which the temperature is increased, and when the polymerization is completed, post-polymerization is performed at a high temperature for curing. In addition, since the polymerization time varies depending on various conditions, it is preferable to determine the optimal time according to these conditions in advance, but in general, 0.
．． It is preferable to select conditions such that polymerization is completed in 5 to 40 hours.

In the case of methods (1) and (2), it is usually preferable to employ bulk polymerization by casting. However, method (2) requires the presence of a photosensitizer. For example, in the method (■), a photosensitizer is blended with the polymerizable monomer component,
In method (2), a high refractive index resin can be easily obtained by directly irradiating the polymerizable monomer component with ultraviolet rays or electron beams. Examples of photosensitizers that can be used in the method (2) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, pency/isobutyl ether,
Photosensitizers such as 2-hydroxy-2-benzoyl gulonone, pennoldimethyl ketal, azobisin butyronitrile, and thioxanthone can be used, and one or more of these are usually used. For the polymerizable monomer component,
It can be used in an amount of 0.01 to 10% by weight, preferably 0.05 to 8% by weight.

In the present invention, which of the methods (1) to (4) is used may be appropriately selected depending on the desired performance of the high refractive index resin, and in some cases, a plurality of methods may be combined.

The high refractive index resin produced by the production method of the present invention may appropriately contain known additives such as ultraviolet absorbers, antioxidants, drip-proofing agents, colorants, and the like.

<Effects of the Invention> Since the high refractive index resin obtained by the production method of the present invention is obtained using polymerizable monomer III) as an essential component, it has a high refractive index and is excellent in colorless transparency. It can be used as a resin for optical materials, such as lenses, optical fibers, optical disks, films, etc., and can also be used for decorative and building material moldings by adding pigments, fillers, etc.

The present invention provides a method for easily obtaining a high refractive index resin having such characteristics.

<Example> Hereinafter, this will be explained in detail using examples.

Example I S-methylthiomethacrylate 100i parts and 2.2
'-Azobis(2,4-dimethylvaleronitrile) 0.
5 parts by weight was poured into a mold made of two glass plates and a silicone rubber gasket, and heated at 50°C for 6 hours.
hr, 16 hr at 60℃ and 2 hr at 90℃
It was heated and polymerized. The obtained high refractive index resin [1] was colorless and transparent. Table 1 shows the physical properties of this high refractive index resin.

Similarly, the physical properties were evaluated as follows.

Colorless transparency: The degree of coloring of the sheet-like polymer obtained by cast polymerization was visually determined.

Refractive index and Atsube number: The refractive index of a small piece of the sheet-like polymer obtained by cast polymerization was measured using an Atsube refractometer, and the Atsube number was determined directly from the dispersion. The larger the Atsube number, the better the derivation characteristics.

Total light transmittance: A sheet-like polymer obtained by cast polymerization was measured using a turbidity meter.

Cutting workability: The sheet-like polymer obtained by cast polymerization was cut with a diamond cutter, and the cut surface was observed for cracks, cracks, and fusion. Items without such information are marked with a circle.

Heat resistance: A sheet-like polymer obtained by cast polymerization was placed in a hot air dryer at 100° C. for 3 hours, and deformation such as warp was observed during this time. Those in which no deformation was observed are marked with a circle.

Examples 2 to 11 High refractive index resin [2] was prepared by repeating the same operation as in Example 1 except that the composition of the polymerizable monomer component in Example 1 was as shown in Table 1. ~[11] was obtained. Their physical properties are also shown in Table 1.

(Note) MTMA Methylthiomethacrylate EGDMA
Ethylene glycol no methacrylate Br4B
M[1lJ)P 2-2-bis(3,5-nopromo-4-methacryloyloxyethoxyphenyl)f ropane St styrene BMTE 1.2-bismethacryloylthioethane TBPMA 2.4.6-dolipromophenyl methacrylate TBTMA t- Butylthiomethacrylate ETMA Ethylthiomethacrylate IPTMA i-furovirthiomethacrylate BTMA Benzylmethylthiomethacrylate MMP 4-methacryloyloxy-2
,2,6,6-titramethylpiperidi/

Claims (1)

[Claims] 1. In a method for producing a high refractive index resin by radical polymerization, a polymerizable monomer represented by the following general formula (1) [
A polymerizable monomer component containing one or more of the above polymerizable monomers [I] as an essential component and, if necessary, another polymerizable monomer [II] that can be radically copolymerized with the polymerizable monomer [I]. A method for producing a high refractive index resin. (Note) General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 is H or CH_3, R_2 is C_1
~C_1_6 represents an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, an alkylthioalkyl group, or an alkyl group substituted with a heterocycle. 2. The method for producing a high refractive index resin according to claim 1, wherein the polymerizable monomer [I] is used in an amount of 5% by weight or more in the polymerizable monomer component. 3. Polymerizable monomer [II] has a homopolymer refractive index of 1
．． 4. The method for producing a high refractive index resin according to claim 1 or 2, wherein the refractive index resin is 48 or more. 4. The method for producing a high refractive index resin according to any one of claims 1 to 3, wherein the obtained polymer has a refractive index of 1.55 or more.