JPS6163802A - Resin for optical use - Google Patents

Abstract

PURPOSE:To obtain a transparent resin having superior heat resistance and adhesive property and suitable for use as a material for the clad of an optical fiber, an optical adhesive or the like by providing specified light transmittance or above and a specified refractive index or below to a resin contg. a specified percentage of a metal other than the alkali metals and fluorine. CONSTITUTION:A salt of a metal other than the alkali metals such as Ba, Mg or Sn and perfluoroalkyl (meth)acrylate are added to a mixture of an unsatd. acid such as (meth)acrylic acid or itaconic acid with (un)satd. carboxylic acid contg. fluorine, and they are copolymerized to obtain a colorless and transparent resin contg. said metal by 1-50wt% of the total amount of the resin and having >=80% light transmittance and <=1.55 refractive index. The metal is used as a cross-linking component. The resulting resin has superior heat resistance and adhesive property and is suitable for use as a material for various optical parts such as a lens and an optical waveguide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a resin for optical use that is transparent and has excellent heat resistance and adhesive properties.

[Background of the invention]

Since resins containing fluorine have a low refractive index, their use as various optical materials including optical fibers has been studied. Among these, copolymers of vinylene fluoride and fluorine-containing olefin monomers such as tetra-70 fluoroethylene, as described in Japanese Patent Publication No. 53-42260, have excellent heat resistance and adhesive properties; The polymer is crystalline and cloudy, so it has the disadvantage of high light scattering. On the other hand, polyfluoromethacrylates and acrylates are known as fluorine-containing resins with excellent transparency, but these polymers generally have poor heat resistance and adhesive properties. Therefore, as a method to solve these drawbacks, a method of copolymerizing and exploding a vinyl monomer capable of forming a hydrophilic homopolymer is disclosed in JP-A-59-15411 and JP-A-59-7906.

It is described in Publications No. 59-9604 and No. 59'-7311.

These methods have improved heat resistance and adhesive properties compared to those that do not use vinyl monomers that can form hydrophilic homopolymers.
Although it can be improved to a certain extent, the thermal decomposition resistance increases with high-temperature heating.6 Also, the glass transition temperature of the resin is low at 90°C or less. Furthermore, since the type of fluoromethacrylate used is limited to 2-3a types such as ethyl and propyl esters, it is difficult to freely adjust the optical properties depending on the type of material. [Object of the Invention] An object of the present invention is to provide an optical resin that is transparent and has excellent heat resistance and layer adhesion.

[Summary of the invention]

To summarize the present invention, the present invention relates to an optical resin, which is composed of a resin containing a metal other than an alkali metal and fluorine, and the content of the metal is 1 weight per total weight of the resin. % or more, and the light transmittance of the resin is 80%.
As mentioned above, the material is characterized in that the refractive index is 1.55 or less.

The inventors 1. As a result of intensive research to improve the shortcomings of the conventional technology, we introduced metals and hydrophilic groups into the fluorine-containing resin, and by ionically bonding the hydrophilic groups with the metal, transparent However, it was discovered that an optical resin with excellent heat resistance and adhesiveness could be obtained, and the present invention was achieved.

Resins containing gold R and fluorine tend to crystallize due to their molecular structure, so it is difficult to make them transparent. Furthermore, compositions containing metals have low solubility in vinyl monomers such as general methacrylic esters or acrylic esters, so fine particles remain in the resin after copolymerization, which scatters transmitted light and makes it transparent. inferior in sex. Therefore, to prevent resin crystallization.

The idea is to ionicly bond a group with a bulky molecular structure to the side chain via a metal. Furthermore, the solubility was increased by selecting a group 2a- which is merely bulky but has good compatibility with the above-mentioned vinyl monomer as a group to be bonded to the side chain. □The resin obtained in this way is
It has at least a remaining fund expressed by the following general formula (1).

R, Coo -・-Mne...K・00CR=)
(n-1') ... (1) (wherein, R represents a group forming the polymer main chain, M represents a metal, R, d represents a group having fluorine, and n represents a metal (represents oxidation number) Therefore, carboxyl groups and metals are effective in improving the adhesiveness of resin.

Furthermore, in addition to the residue represented by the general formula (1), a residue represented by the following general formula (2) can also be introduced into the resin by changing the blending amount of the organic carboxylic acid. .

R1C00O---Mne---(θ0OCRt)(n
-1)"(2) Therefore, ionic crosslinking of carboxyl groups by metal becomes possible, which is effective for the purpose of improving heat resistance.

In the present invention, the transparent resin containing metal and fluorine is produced by using the above formula (1), or a composition represented by formulas (1) and (2) alone or by copolymerizing it with a general vinyl monomer. Obtainable. 6 In the present invention, the above (1)
), formula (2) As the organic carboxylic acid used for R1, ethylenic mono- or dicarboxylic acid monomers are used, such as acrylic acid, methacrylic acid, itaconic acid monoalkyl ester salt, itaconic acid, Examples include crotonic acid, maleic acid, hexamalic acid, glutaconic acid, and citraconic acid. Among these, methacrylic acid, acrylic acid, and itaconic acid monoalkyl ester salts are particularly effective in terms of transparency and heat resistance.

In the present invention, the fluorine-containing carboxylic acid used for the group R2 represented by the above formula (1) includes, for example, a saturated or unsaturated aliphatic carboxylic acid, a saturated or unsaturated carboxylic acid containing a benzene ring, etc. However, for the purpose of lowering the refractive index of the resin, saturated or unsaturated aliphatic carboxylic acids are useful.

Examples of saturated aliphatic carboxylic acids include heptafluorobutyric acid, pentafluoropropionic acid, perfluorodecane, perfluorooctanoic acid, perfluorohebbutanoic acid, perfluorononane ffi, +1H-icosafluoroundecanoic acid. , 3-trifluoromethyl-5-hydroxybutyric acid, etc. Examples of unsaturated aliphatic carboxylic acids include β-trifluoromethylcrotonic acid.

These compounds can be used alone or in combination of two or more, but it is of course also possible to use them in combination with a fluorine-free saturated or unsaturated aliphatic carboxylic acid.

In the present invention, the metals contained in the plastic include Pb,
Ba%Sr, Zn%Sn, Sb%Mg%H
g.

Ca, La, Ti, Zr%Ta%Th, Nl),
Tt.

Ge, C! s%cd etc. Particularly useful among these are Pb, Ba, Sr%Zn, Mg,
Ca.

These include La, Cid, and Hg, but an appropriate metal can be selected depending on the refractive index of the resin. Further, these metals may be contained alone or in combination of two or more.

In the present invention, the above formula (1), or formula (1) and (2)
) Examples of vinyl monomers copolymerized with the composition represented by the formula include methyl methacrylate, ethyl methacrylate,
n-propyl methacrylate, n-7' thyl methacrylate, t-butyl methacrylate, lauryl methacrylate, nonyl methacrylate, methyl acrylate,
Examples include butyl acrylate, 2-ethylhexyl acrylate, and the like, but methacrylate is preferred from the viewpoint of copolymer properties. Please note that in addition to the above monomers (fluoromethacrylate monomers, fluoroacrylate monomers, etc.) may also be used.As the fluoroalkyl methacrylate monomers, trifluoroethyl methacrylate, 2.2.A3-tetrafluoropropyl methacrylate, 2.2. 3゜3,3-pentafluoropropyl methacrylate, 2-trifluoromethyl-3, mu3
-Trifluoropropyl methacrylate, 2-trifluoromethyl-Otsugo 3-tetrafluoropropyl methacrylate, 2.2. A4.4.4-Hexafluorobutyl methacrylate, 2.2°3, A4. A, 4
-Hebutafluorobutyl methacrylate, 1-methyl-
2,2,A 4.4.4-Hexafluorobutyl methacrylate, 1.1.2.2-tetrahydroperfluorodeflu methacrylate, 1゜1,2.2-tetrahydro-9-trifluoromethylperfluorodecyl methacrylate , 1.1-dihydroperfluorobutyl methacrylate, 1.1-dimethyl-2,2,A3-tetrafluoropropyl methacrylate, 1.1-dimethyl-2,
2゜55-4.4.5.5-octafluoropentyl methacrylate, 1,1-dimethyl-Otsu 2.314.4.4
-hexafluorobutyl methacrylate and the like. As the fluoroalkyl acrylate monomer, trifluoroethyl acrylate, 2.2. A5.3-pentafluoropropyl acrylate, 1-methyl-2,
2,5-3-tetrafluoropropyl acrylate, 1,
1-Dimethyl-2,2゜-3-tetrafluoropropyl acrylate, 2,2.3.4.4.4-hexafluorobutyl acrylate, 2,2.55-4.4.4-heptafluorobutyl acrylate , 1-methyl-2,'L
3.4,4.4-hexafluorobutyl acrylate,
Examples include 1.1-dimethyl-2,'Z, l 4.4°4-hexafluorobutyl acrylate. The above fluoroalkyl acrylates and fluoroalkyl acrylates may be used alone or in combination of two or more.

The content of fluorine introduced in this manner is preferably 510 or more based on the total weight of the resin. When the weight is less than 5%, there is little effect on lowering the refractive index of the resin. Further, the fluorine content can be determined based on the transparency of the resin.

Transparent resin containing metal and fluorine can be produced, for example, as follows.

Mix M-yagura, carboxylic acid, and metal compounds (the above-mentioned metal commercial products, hydroxides, chlorides, nitrates, acetates, carbonates, etc.) in a solvent such as alcohols or ketones in a predetermined ratio, and leave the mixture at room temperature. Alternatively, the reaction can be carried out by stirring at a low temperature. After this go, a clear homogeneous liquid is obtained. In this case, the combination of organic carboxylic acid and metal compound -! lth
It varies depending on each type. Further, since by-products generated by the reaction, water, unreacted substances, etc. are dissolved in these solutions, these by-products and the solvent are removed by distillation under reduced pressure. This composition alone or by adding a predetermined amount of vinyl monomer to form a monomer composition is cured by heat, ultraviolet rays, or the like. In this case, the polymerization method includes emulsification,
Although suspension, bulk or solution polymerization may be used, bulk polymerization is preferred in order to obtain a highly pure polymer.

Polymerization initiators used when thermally curing the obtained monomer composition include benzoyl peroxide, lauroyl peroxide, diisopropyl peroxydicarbonate, dimyristyl peroxydicarbonate, and azobisisobutyronitrile. Usual radical polymerization initiators such as the following can be used. In addition, when curing with ultraviolet rays, benzoin propyl ether, benzoin ethyl ether, pentwinisobutyl ether, α-allyl benzoin, α-methylbenzoin, benzophenone, benzyl, 2-ethylant 2 are used as polymerization initiators. Quinone etc. can be used. These ultraviolet curing type polymerization initiators can not only be used alone, but also thermosetting type polymerization initiators can be used in combination.

The amount of polymerization initiator is based on 100 parts by weight of the monomer composition,
It is possible to mix α02 to 5 parts by weight.

In the optical resin of the present invention that can be obtained as described above, the light transmittance means a value measured according to the regulations of M8'l'M-100s, and the refractive index means nvO
means value.

Therefore, in the present invention, the resin specified to have a light transmittance of 8Q9j or more has good transparency, so it can be used not only as a cladding material for optical fibers, but also as a regular optical resin plate or TL film. Can be used.

On the other hand, in the case of a resin with a light transmittance of less than 80 cm, the optical fiber has a large optical loss, and in the case of a normal resin plate, the thicker the plate, the greater the absorption and scattering of light, which significantly impairs transparency. Due to these drawbacks, it is not suitable for use in optical applications.

Furthermore, the optical resin of the present invention has various uses, such as cladding materials for optical fibers, adhesives for quartz glass or acrylic resin, and modifiers for acrylic resins due to its low refractive index. It is desirable that there be. in general,
Polystyrene (refractive index n!Smi 1.59) and polymethyl methacrylate (refractive index fi!'==149) are mainly used as core materials in plastic optical fibers, so the clad material The refractive index is at most nv
= 1.55 is the limit, and in order to increase the numerical aperture of the optical fiber, a lower refractive index becomes the sensitivity difference.

Therefore, it is essential that the optical resin used in the present invention has a refractive index nM of 1.55 or less, but as long as this condition is satisfied, the refractive index of the resin can be freely controlled depending on the application. I can do it.

[Embodiments of the invention]

In order to explain the present invention more specifically, the present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The physical properties of the resulting resin were measured using the following test methods.

(1) Refractive index The refractive index at 25°C was measured using the refractive index of Atsube. (A8TM-100
3) (3) Heat distortion temperature (7g) Heat distortion temperature (Tg3t!) was measured from the temperature change in linear expansion coefficient using a thermophysical tester TMA (manufactured by Shinku Riko Co., Ltd.).

(4) Heat Resistance The heat resistance is after being released for 206 seconds (in the air), and the amount of electricity is 1.1%. I guessed it.

(5) Using two 2×4 quartz glass plates with adhesive optical polishing,
The above monomer composition was applied to the ×2 ctn portion, and they were bonded to each other. These two glass plates were fixed with pressure and a spring, and heated at 60° C. for 3 hours and at 80° C. for 2 hours. This product was soaked alternately in cold water at 0°C and hot water bath at 80°C, and heat cycle test t-
After repeating 500 times, the state of adhesion was examined.

Hereinafter, methods for producing resins are shown in Examples 1 to 8 and Comparative Examples 1 and 2, and characteristics of these resins are shown in Table 1.

In addition, in 6 examples, 1 part means the amount taken.

Example 1: 100 ml of methyl alcohol, 12 parts of methacrylic acid, and 57 parts of perfluorooctane powder. tl and 55℃
After maintaining the temperature, 31 parts of -lead oxide was gradually added to carry out the reaction. After filtering this solution, water and methyl alcohol
The monomer composition was obtained by removing under pressure. This monomer 15
50 parts of composition, 2.2. 55.4.4.50 parts of 4-heptafluorobutyl methacrylate and 0.3 parts of similystyl peroxydicarbonate as a polymerization initiator were mixed uniformly at 60°C for 3 hours and at 80°C for 3 hours in a nitrogen gas atmosphere. Make sure to carry out the bulk polymerization reaction.

Example 2 After 25 parts of methacrylic acid and 45 parts of perfluorooctanoic acid were dissolved in 100 d of methyl alcohol and maintained at 50°C, 30 parts of -lead oxide was gradually added to carry out a reaction.

After filtering this solution, water and methyl alcohol were removed under reduced pressure to obtain a monomer composition. This monomer composition 100
per part, cimilistyl peroxydicarbonate c
1 part of L was added and mixed at 60°C, and then heated at 60°C under nitrogen.
A bulk polymerization reaction was carried out at 80° C. for 3 hours.

Example 3 20 parts of the nine monomer set paraboloid obtained in Example 1, 2.2.2
- 80 parts of trifluoroethyl methacrylate and 2 parts of similystyl peroxydicarbonate Q were uniformly mixed, and a bulk polymerization reaction was carried out at 55°C for 3 hours and at 80°C for 3 hours in nitrogen.

Example 4 After dissolving 26 parts of afrylumi and mss part of perfluorooctane in 100-g of methyl alcohol and maintaining at 55°C, barium hydroxide monohydrate CBa(OH)2-a2
o ] 19 parts was gradually added to carry out the reaction. After P7a of this solution, water and methyl alcohol were removed under reduced pressure to obtain a monomer composition. 60 parts of this monomer composition, 2.
2.2-) 40 parts of trifluoroethyl methacrylate and 2 parts of similisyl peroxydicarbonate Q were uniformly mixed, and a combination reaction was carried out in the same manner as in Example 3.

Example 5 11 parts of methacrylic acid and 48 parts of perfluorohebutane were dissolved in 100% methyl alcohol and kept at 55°C.
20] 41 parts were gradually added to carry out the reaction. After filtering this solution, water and methyl alcohol are removed under reduced pressure to obtain a monomer composition. 20 parts of monomer composition, 2.2
．． 2-)! 80 parts of J fluoroethyl methacrylate and 12 parts of dimyristyl peroxydicarbonate were uniformly mixed, and a single reaction was carried out in the same manner as in Example 3.

Example 6 11 parts of methacrylic acid in 100-methyl ethyl ketone,
After 54 parts of perfluorooctanoic acid was dissolved and maintained at 55° C., 35 parts of strontium hydroxide was gradually added by 71 D to carry out the reaction. After filtering this solution, water and methyl ethyl ketone were removed under reduced pressure to obtain a monomer composition.

This mono ff-fJlgml 5%, 2.2. A53-
85 parts of pentafluoropropyl methacrylate and 13 parts of similystyl peroxydicarbonate were mixed uniformly, and a polymerization reaction was carried out in the same manner as in Example 3.

Example 7 After adding 31 parts of methacrylic acid and 54 parts of perfluorooctanoic acid to 100 d of methyl alcohol and maintaining the mixture at 55° C., 15 parts of barium hydroxide 1 water λ salt was gradually added to carry out a reaction. After filtering this solution, water and methyl alcohol were removed under reduced pressure to obtain the monomer composition 't, L%.
Ta. 15 parts of this monomer composition, 10 parts of methyl methacrylate, 5 parts of 2,2.3.3.3-pentafluoroprobyl methacrylate-8, and 0.3 part of dimyristilbaroquine dicarbonate were uniformly mixed, A polymerization reaction was carried out in the same manner as in Example 3.

Example 8 Itaconic acid monomethyl ester 2 b parts % barfluorohebbutanoic acid 6 in 100 rRt methyl ethyl ketone
After dissolving 7 parts and maintaining the temperature at 55°C, 7 parts of magnesium oxide was gradually added to carry out the reaction. This melt'ffL1
ft: After filtration, water and methyl ethyl ketone were removed under reduced pressure to obtain a monomer composition.

30 parts of this 7-mer composition, 70 parts of 2.2.2-)lifluoroethyl methacrylate, and 12 parts of dimylinutyl peroxydicarbonate were uniformly mixed, and a polymerization reaction was carried out in the same manner as in Example 3. Ta.

Comparative Example 1 2, 2. i 3 parts of dimylisterperoxydicarbonate α was dissolved in 100 parts of 3-pentafluoropropyl methacrylate, and the mixture was heated at 60°C for 5 hours in a nitrogen gas atmosphere.
A bulk polymerization reaction was carried out at 80° C. for 3 hours.

Comparative Example 2 2, λ&5 70 parts of 3-pentafluoropropyl methacrylate, 28 parts of methyl methacrylate, -bonate 0.
[Effects of the Invention] As explained in detail above, the optical resin containing metal and fluorine according to the present invention is transparent. It has a low refractive index nHs of 1655 or less, and has excellent heat resistance and adhesive properties, so it is used not only as a clad material for optical fibers and general optical resin plates, but also as optical adhesives, lenses, etc. It can be used as a material for various optical components such as optical waveguides.

Therefore, the present invention is an invention that has remarkable effects in terms of its usefulness.

Claims (1)

[Claims] 1. Consisting of a resin containing a metal other than an alkali metal and fluorine, the content of the metal is 1% by weight or more based on the total weight of the resin, and the resin has a light transmittance. rate is 80% or more,
An optical resin having a refractive index of 1.55 or less. 2. The optical resin according to claim 1, wherein the content of the metal is 2 to 50% by weight based on the total weight of the resin. 3. The content of fluorine is 5% by weight based on the total weight of the resin.
The optical resin according to claim 1, which is the above. 4. A patent claim in which the resin includes at least one carboxylic acid polymer substance having at least one carboxyl group in the polymer chain that is ionically bonded to the carboxyl group of a fluorine-containing carboxylic acid via a metal. The optical resin according to item 1.