JPS6234321B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention particularly relates to a method for producing a high refractive index resin with excellent moldability. Conventionally, various synthetic resins have been researched and proposed to replace inorganic glass, but synthetic resins such as diethylene glycol bisallyl carbonate polymers have a refractive index as low as 1.49 compared to inorganic glasses. In recent years, the refractive index of synthetic resins has been further improved,
Proposals have been made to produce high refractive index resins.
For example, JP-A-55-13747 and JP-A-54-77686. In order to obtain these high refractive index resins, it is necessary to use monomers with high refractive index, and generally dimethacrylates, diacrylates, etc. having aromatic rings are used.
Monofunctional vinyl compounds having aromatic rings, methacrylates and acrylates have been proposed as monomers. However, in the case of high refractive index resins such as those mentioned above, the refractive index has improved to 1.58 to 1.61, but in order to increase the refractive index, monomers with aromatic rings are generally used as raw material monomers. Therefore, the hydrophobicity of the monomer is large. On the other hand, materials such as glass and metal are generally used as molds for cast polymerization, and both have hydrophilic surfaces. Therefore, in the cast polymerization of a monomer having an aromatic ring as described above, the adhesion between the monomer and the mold is poor, and the surface condition of the cast polymer is particularly poor.
Polymerization moldability is poor, such as surface unevenness caused by shrinkage during polymerization. Therefore, especially when obtaining optical elements such as lenses as cast polymers, poor surface conditions of the polymers are a fatal drawback.
Not only does it have no commercial value, but it also reduces product productivity. Therefore, the above-mentioned cast polymerization is generally carried out by curing at a relatively low temperature for a long time and then lowering the temperature to a high temperature for a short period of time to perform post-curing, but even then, the surface condition of the cast polymer remains It's bad (very uneven) and requires quite severe operation. The present inventors, when manufacturing a high refractive index resin,
We have discovered that by adding a radically polymerizable monomer having an alcoholic hydroxyl group, a resin with excellent moldability can be obtained without deterioration in high refractive index and other physical properties, and in order to provide the present invention. I've reached it. That is, in the present invention, when copolymerizing a first monomer of dimethacrylate or diacrylate having an aromatic ring and a radically polymerizable second monomer having an aromatic ring, a radically polymerizable monomer having an alcoholic hydroxyl group is used. This is a method for producing a high refractive index resin with excellent moldability, which is characterized by adding a third monomer. According to the present invention, since the adhesion between the monomer to be cast-polymerized and the mold is good, the surface condition of the resin obtained by cast-polymerization is good, and there are almost no surface irregularities caused by shrinkage. do not have. In addition, depending on the type of the third monomer added in the present invention, it is possible to obtain a resin that has not only moldability but also improved dyeability and adhesion with the coating film because it has a hydrophilic alcoholic hydroxyl group. be able to. The present invention will be explained in detail below. The first monomer of dimethacrylate and diacrylate having an aromatic ring used in the present invention includes:
It is a general term that includes its nuclear halogen-substituted products.
Any known material can be used without particular limitation. Typical examples that can be suitably used are as follows. For example, 1,4-dimethacryloxybenzene, 1,4-diacryloxybenzene, 1,3
-, dimethacryloxybenzene, 1,3-diacryloxybenzene, dimethacryloxy-phenylmethane, diacryloxy-phenylmethane, di(2-methacryloxyethyl) terephthalate,
Di(2-acryloxyethyl) terephthalate, 1,5-dimethacryloxinaphthalene, 1,5
-Diacryloxyethoxynaphthalene, 2,2-
bis(4-methacryloxyphenyl)propane,
2,2-bis(4-acryloxyphenyl)propane, 2,2-bis(4-methacryloxyethoxyphenyl)propane, 2,2-bis(4-acryloxyethoxyphenyl)propane, bis(4-methacryloxyphenyl)propane
-methacryloxyphenyl) sulfone, bis(4
-acryloxyphenyl) sulfone, bis(4-
Methacryloxyethoxyphenyl) sulfone, bis(4-acryloxyethoxyphenyl) sulfone, bis(4-methacryloxypropoxyphenyl) sulfone, etc. are used. Particularly in the present invention, when the above-mentioned dimethacrylate and diacrylate substituted with nuclear halogen (however, fluorine is excluded) is used, a resin having a high refractive index and further imparted with flame retardancy can be obtained. Examples of such nuclear halogen (excluding fluorine) substituents include 1,4-dimethacryloxy-2,3,5,6-tetrabromobenzene, 1,4-diacryloxy-
2,3,5,6-tetrabromobenzene, dimethacryloxy-di(4-chlorophenyl)methane,
Tetrabromophthalate-di(2-methacryloxyethyl), Tetrabromophthalate-di(2-
acryloxyethyl), 2,2-bis(4-methacryloxy-3-chlorophenyl)propane,
2,2-bis(4-acryloxyethoxy-3,
5-dibromphenyl)propane, 2,2-bis(4-methacryloxy-3-bromphenyl)propane, 2,2-bis(4-acryloxy-3,
5-dibromophenyl)propane, 1,5-dimethacryloxy-2,4,6,8-tetrachloronaphthalene, 1,5-dimethacryloxyethoxy-
2,4,6,8-tetrabromnaphthalene, bis(4-methacryloxyethoxy-3-bromophenyl) sulfone, bis(4-methacryloxyethoxy-3-chlorophenyl) sulfone, bis(4-methacryloxyethoxy-3-chlorophenyl) sulfone
-methacryloxyethoxy-3,5-dibromophenyl) sulfone, bis(4-methacryloxyethoxy-3,5-dichlorophenyl) sulfone,
Bis(4-methacryloxy diethoxy-3,5
-dibromophenyl) sulfone, bis(4-methacryloxydiethoxy-3,5-dichlorophenyl) sulfone, bis(4-methacryloxypropoxy-3,5-dibromophenyl) sulfone,
Bis(4-methacryloxypropoxy-3,5-
dichlorophenyl) sulfone, etc. are used. Further, as the radically polymerizable second monomer having an aromatic ring used in the present invention, vinyl, methacrylate, acrylate, etc. are preferable, and those having a homopolymer having a refractive index of 1.55 or more are particularly preferable. For example, styrene; styrene derivatives such as vinyltoluene and methoxystyrene; nuclear halogen-substituted styrenes such as chlorstyrene, bromstyrene, iodostyrene, dichlorostyrene, dibromstyrene, trichlorostyrene, and tribromstyrene; phenyl methacrylate, phenyl Acrylate, Chlorphenyl methacrylate, Dichlorophenyl methacrylate, Bromphenyl methacrylate, Dibromphenyl methacrylate, Dibromphenyl acrylate, Methoxyphenyl acrylate, Benzyl methacrylate, Benzyl acrylate, Chlorbenzyl methacrylate, Chlorbenzyl acrylate, Brombenzyl methacrylate, bromobenzyl acrylate, dibromobenzyl methacrylate,
Acrylates and methacrylates such as dichlorobenzyl methacrylate, dibromobenzyl acrylate, tribromobenzyl methacrylate, pentabrome methacrylate, tribrome methacrylate, pentachlor methacrylate, trichlormethacrylate, pentabrome acrylate; other α-naphthyl methacrylate, β
- Naphthyl methacrylates such as naphthyl methacrylate; vinylnaphthalenes such as phenoxyethyl acrylate, phenoxyethyl methacrylate, 1-vinylnaphthalene, 2-vinylnaphthalene; 4-vinylbiphenyl, vinylphenyl sulfide, etc., and mixtures thereof etc. Further, the radically polymerizable three monomers having an alcoholic hydroxyl group used in the present invention are not particularly limited, and known ones can be used. Typical examples that can be suitably used as the third monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1-methyl-2
-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 1-methyl-2-hydroxyethyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, hydroxymethyl acrylamide , hydroxymethyl methacrylamide, tetramethylolmethane triacrylate, aliphatic monohydroxy methacrylates or acrylates such as tetramethylolmethane trimethacrylate; 2,3-dihydroxypropyl methacrylate, 2,3-dihydroxypropyl acrylate, ethylene glycol di(3 ―
Methacryloxy-2-hydroxypropyl ether), ethylene glycol di(3-acryloxy-2-hydroxypropyl ether), propylene glycol di(3-methacryloxy-2-hydroxypropyl ether), 2-hydroxypropylene glycol di(3-methacryloxy- 2-
Aliphatic polyhydroxy methacrylates or acrylates such as hydroxypropyl ether); 3-phenoxy-2-hydroxypropyl methacrylate, 3-phenoxy-2-hydroxypropyl acrylate, P-hydroxymethylbenzyl methacrylate, P-hydroxymethylphenyl methacrylate , P-hydroxymethylphenyl acrylate, (2-methacryloxyethyl)-(2-hydroxyethyl)-terephthalate, (2-methacryloxyethyl)-(2-hydroxyethyl)phthalate, and other monohydroxy methacrylates having an aromatic nucleus. or acrylates; 2,2-bis[4(3-methacryloxy-
2-hydroxypropoxy)phenyl]propane, 2,2-bis[4-[3-(3-methacryloxy-2-hydroxypropoxy)-2-methylpropoxy]phenyl]propane, 2,2-bis[4(3- Dihydroxymethacrylates or acrylates with an aromatic ring such as acryloxy-2-hydroxypropoxy)phenyl]propane; also diallyl tartrate (diallyl tartrate), diallyl mareate (diallyl malate), triallyl citrate (triallyl citrate) , diethylene glycol monoallyl carbonate, allyl esters having an alcoholic hydroxyl group such as 3-butenoic acid glycerin ester, and mixtures thereof. The first monomer has a ratio of 1 to 99 with respect to the second monomer.
It is most commonly used in weight percent, preferably in the range of 5 to 95 weight percent. That is, if the amount of the first monomer used relative to the second monomer is small, the mechanical properties of the copolymer will deteriorate. On the other hand, if the amount of the first monomer used is too large, the crosslinking density becomes too high, which tends to increase the coloring and brittleness of the copolymer. Therefore, the amounts of the first monomer and the second monomer to be used are preferably determined in advance depending on the physical properties required for the copolymer. The amount of the third monomer to be used varies depending on the polymerization type, polymerization conditions, the type and amount of the first monomer and the second monomer, and the type of the third monomer, but cannot be absolutely limited. If the amount is too small, the surface condition of the resin obtained will be poor and the effects of the present invention will not be exhibited, and if it is too large, the mechanical properties of the resin obtained will be deteriorated. Therefore, it is generally most suitable to use it in an amount of 0.01 to 20 parts by weight, preferably 0.02 to 15 parts by weight, based on the first and second monomers. In the present invention, a high refractive index resin with excellent moldability is produced by polymerizing a mixture of the first monomer, second monomer, and third monomer in the presence of a radical polymerization initiator. You can get it. The above-mentioned radical polymerization initiator is not particularly limited and any known one can be used, but typical examples include common radical polymerization initiators such as diisopropyl peroxycarbonate, azobisisobutyronitrile, and benzoyl peroxide. The amount of radical polymerization initiator used varies depending on the polymerization type, polymerization conditions, type of monomer in the copolymerization component, and type and amount of the third monomer, but generally it is It is most suitable to use it in a range of 0.0001 to 10% by weight. The first monomer of dimethacrylate and diacrylate having an aromatic ring in the present invention and the refractive index are
The method of copolymerizing the monofunctional vinyl, methacrylate, and acrylate second monomer having an aromatic ring of 1.55 or more and the radically polymerizable third monomer having an alcoholic hydroxyl group is not particularly limited. Known polymerization methods can be employed. An example of a typical polymerization method is a cast polymerization method. For example, a mixture of the copolymer monomers containing a radical polymerization initiator may be injected into a mold held by an elastomer gasket or a spacer, cured in an air oven, and then taken out. It is also possible to preliminarily polymerize a mixture of the copolymerizable monomers described above in the presence of a polymerization initiator to increase the viscosity of the mixture, and then perform cast polymerization. Among the polymerization conditions, temperature particularly affects the properties of the high refractive index resin obtained. Generally, it is preferable to carry out so-called two-stage polymerization, in which polymerization is started slowly at a relatively low temperature and then cured at a high temperature when the polymerization is completed. For example, after polymerizing slowly at room temperature to 70℃,
It is preferable to terminate the polymerization at a high temperature of about 120°C. Of course, taper polymerization is also a preferred method. Since the polymerization time varies depending on various conditions, it is preferable to determine the optimal time according to these conditions in advance, but it is generally preferable to select conditions so that copolymerization is completed in 2 to 40 hours. . Of course, during the copolymerization, additives such as ultraviolet absorbers, antioxidants, various stabilizers, color inhibitors, antistatic agents, fluorescent dyes, etc. can be selected and used as necessary. In order to explain the present invention more specifically, comparative examples and examples will be described below, but the present invention is not limited to these examples. The physical properties of the high refractive index resins obtained in Examples and Comparative Examples were measured by the following test methods. (1) Refractive index The refractive index at 20°C was measured using an Atsube refractometer. Monobromnaphthalene was used as a contact liquid. (2) Surface condition of the cast polymer. Visually observe the surface (front and back) of the cast polymer. ◎ when both sides are smooth. ○ when there is very slight unevenness after careful observation. A case where there were sharp irregularities was rated as △, and a case where unevenness was observed on the entire surface was rated as ×. Furthermore, among the 10 polymerized sheets, the number (x) of sheets in which polymerization peeled off was expressed as x/10. (3) Dyeability The ease of dyeing when dyed with disperse dye at 80° x 15 minutes is shown below. ◎ means it can be dyed well, 〇 means it can be dyed normally, △ means it can be dyed but it is weak, × means it cannot be dyed. (4) Coating properties Glass was vapor-deposited and immersed in boiling water for 24 hours, and those with no film peeling were rated ◎, and the others were rated ×. Examples 1 to 6 Chlorstyrene (65% by weight of ortho form, 35% of para form)
2,2-bis(4-methacryloxyethoxyphenyl)propane with the composition shown in Table 1 was added to the mixture (% by weight mixture), and ethylene glycol bis[3-methacryloxy(2-hydroxy)propyl ether] was added. The composition shown in Table 1 was added, and 1.0 part by weight of diisopropyl peroxydicarbonate was added as a radical polymerization initiator and thoroughly mixed. This mixed solution was poured into a mold consisting of a glass plate with a diameter of 73 mm and a gasket made of ethylene-vinyl acetate copolymer, and cast polymerization was performed.
For polymerization, the temperature was gradually raised from 30°C to 80°C in 20 hours using an air oven. Polymerization was further carried out at 80°C for 2 hours. After polymerization, remove the mold from the air furnace and
After removing the gasket and allowing it to cool, the polymer was peeled off from the glass mold. Various physical properties of the polymer were measured and shown in Table 1. Comparative Examples 1 to 3 Example 1 except that ethylene glycol bis[3-methacryloxy(2-hydroxy)propyl ether] was not used in Examples 1 to 6.
It was carried out in exactly the same manner as in 6. The results are shown in Table 1. From Table 1, it is clear that the effect of adding the polymerizable third monomer having an alcoholic hydroxyl group in the present invention is excellent. That is, when ethylene glycol bis[3-methacryloxy(2-hydroxy)propyl ether] is added as the third monomer, the adhesion between the glass plate of the mold and the copolymer is improved, probably because the casting polymer The surface condition becomes very good. In addition, the addition of EGBMHPE has shown a positive effect on the dyeability of the copolymer.

[Table] Examples 7 to 12 To 40 parts by weight of styrene, 60 parts by weight of 2,2-bis(4-methacryloxyethoxy-3,5-dibromophenyl)propane was added, and then various tertiary compounds shown in Table 2 were added. The monomers were added, and 1.0 parts by weight of dimyristyryl peroxydicarbonate as a radical polymerization initiator was added and thoroughly mixed. The rest was carried out in exactly the same manner as in Examples 1 to 6. The results are shown in Table 2.

【table】

[Table] Comparative Example 4 Examples 7 to 12 were carried out in exactly the same manner as in Examples 7 to 12, except that the third monomer was not used.
The results are shown in Table 2.

Claims (1)

[Claims] 1. When copolymerizing a first monomer of dimethacrylate or diacrylate having an aromatic ring and a radically polymerizable second monomer having an aromatic ring,
A method for producing a high refractive index resin, which comprises adding a radically polymerizable third monomer having an alcoholic hydroxyl group. 2. The method for producing a high refractive index resin according to claim 1, wherein the third monomer is a methacrylate or acrylate having an alcoholic hydroxyl group. 3. The method for producing a high refractive index resin according to claim 1, wherein the third monomer is an allyl ester having an alcoholic hydroxyl group.