JPS60194401A - Optical element - Google Patents

Abstract

PURPOSE:To obtain an optical element having a high refractive index and causing no yellowing, especially a lens by using polyurethane obtd. by reacting a specified S-contg. polyol combined optionally with other polyhydric compound contg. active hydrogen with polyisocyanate. CONSTITUTION:An S-contg. polyol having a bivalent residue or higher represented by formula I (where each of R<1> and R<2> is lower alkyl, halogen or a bonding radical, and each of k and l is 0, 1 or 2) and two or more alcoholic OH groups or a combination of >=10wt% said polyol with other polyhydric compound contg. active hydrogen is reacted with a polyisocyanate compound to obtain polyurethane resin. Said polyol includes a compound represented by formula II (where A is a bivalent residue represented by the formula I , R is 2-4C alkylene, and m>=1). When the resulting polyurethane resin is used, an optical element having about 1.60 high refractive index, free from haze, causing no yellowing, and having superior light and heat resistances, especially a lens is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to optical elements (2) made of polyurethane synthetic resin, and in particular to eyeglass lenses and other optical elements made of polyurethane synthetic resin obtained from a specific sulfur-containing polyol as a raw material. It relates to optical elements.

Optical elements such as glasses, cameras, and projector lenses have traditionally been made of glass and certain synthetic resin materials.

In particular, diethylene glycol bisallyl carbonate (hereinafter referred to as DGBAO) polymer and polymethyl methacrylate are used as synthetic resin materials because they are lighter, stronger and more transparent than glass, and have less birefringence. It was widely used. However, since these synthetic resins have a low refractive index of about 1.5, their range of application has been inevitably limited. Moreover, with the recent progress in optoelectronic technology and the spread of copying machines, facsimile machines, video cameras, etc., it has become possible to produce lenses with higher refractive indexes such as irregularly shaped lenses, Fresnel lenses, diffraction gratings, aspheric lenses, etc. at high speeds and high speeds. In order to develop synthetic resin materials that can be manufactured with precision (3), the development of new synthetic resin materials is desired.

Taking eyeglass lenses as an example, most conventional synthetic resin eyeglass lenses are made of DGBAO polymer. DG
BAO is well known under the trade name 1'''0R-39J.

In recent years, the development of synthetic resin materials for eyeglass lenses with high refractive index has progressed, and polymerizable monomers having a halogenated aromatic nucleus, particularly a brominated aromatic nucleus, are known as relatively successful examples. For example, representative monomers include (meth)acrylic acid ester of nuclear brominated hisphenol AR conductor and nuclear brominated styrene. Although these polymers of brominated aromatic monomers have a refractive index close to about 1.6, they still have various problems in practical use as optical elements.

The biggest problem with polymers of brominated aromatic monomers as optical elements is their weather resistance, particularly the fact that they are easily colored.

Other properties such as hardness, except for the refractive index, are sufficiently satisfactory compared to conventional DGBAO polymers. The reason for the low weather resistance of polymers of brominated aromatic nucleus (4) monomers is thought to be that bromine atoms are easily detached from the aromatic nucleus by the action of light or heat. Furthermore, bromine atoms are likely to be eliminated by the action of radical-generating polymerization initiators, and therefore, even if the monomer itself is sufficiently purified, the polymer is likely to be colored. Aromatic nuclei also have the effect of increasing the refractive index. Therefore, polymers of aromatic vinyl monomers (such as styrene) that do not contain halogens have a somewhat high refractive index and have few problems in weather resistance, but are difficult to satisfy in terms of mechanical properties and the like. In addition, although the specific gravity of the polymer of brominated aromatic monomer is lighter than that of glass, DG
It also has a melting point that is much higher than that of BAO polymers and is not necessarily sufficient in terms of weight reduction.

The present inventors have studied synthetic resins for optical elements that can solve the above problems. Since it is difficult to obtain the desired refractive index with aromatic nuclei alone, we conducted research on polymers that contain components effective in improving the refractive index in addition to aromatic nuclei.
It has been found that a polyurethane synthetic resin containing an aromatic nucleus and a sulfur atom is desirable. Lenses made of polyurethane synthetic resin are basically known, for example, disclosed in Japanese Patent Application Laid-Open No. 57-1
They are described in Japanese Patent No. 36601, West German Patent No. 2929313, US Pat. No. 3,907,865, US Pat. No. 3,954,584, etc. However, these conventional optical elements made of polyurethane synthetic resins were not always satisfactory due to reasons such as insufficient refractive index and insufficient weather resistance. The present inventor has discovered that a polyurethane synthetic resin obtained using a specific sulfur-containing polyol as a raw material has a high refractive index as an optical element and also has excellent other physical properties such as weather resistance. The present invention relates to an optical element made of this specific polyurethane synthetic resin, namely, a sulfur-containing polyol containing a divalent or higher residue represented by the following formula [I] and two or more alcoholic hydroxyl groups. , or a polyurethane obtained by reacting a combination of the (6) sulfur-containing polyol and another polyvalent active hydrogen-containing compound, and a polyisocyanate compound, in which the proportion of the sulfur-containing polyol is at least 10% by weight. Optical element made of synthetic resin.

RlkBZ but Hl, Hl: Same or different lower alkyl group, halogen atom, or bond, 1: 1, 1, or 2, respectively In the present invention, the polyisocyanate compound is preferably a non-yellowing polyisocyanate described below. . Polyurethane synthetic resins obtained using yellowing polyisocyanates tend to yellow when exposed to ultraviolet light. Therefore, when used as an optical element with little risk of exposure to ultraviolet light, yellowing polyisocyanate can be used as a raw material.

However, preferably a non-yellowing polyisocyanate is used as the polyisocyanate compound (7). Similarly, it is more preferable that the sulfur-containing polyol does not contain nitrogen. However, polyurethane resins obtained using sulfur-containing polyols containing NO-RODAN have better weather resistance and lower specific gravity than conventional polymers of aromatic monomers containing NO-RODAN. . The reason for the former is that the production of polyurethane synthetic resin does not require the use of a radical-generating polymerization initiator. Therefore, when a high refractive index is required even if the weather resistance is low to some extent, it is preferable to use a sulfur-containing polyol containing nitrogen.

The sulfur-containing polyol in the present invention must contain a divalent residue represented by the above formula [I] (hereinafter referred to as a sulfur-containing nucleus) and two or more alcoholic hydroxyl groups. A typical starting material for producing sulfur-containing polyols is a diphenol having a sulfur-containing nucleus and two hydroxyl groups bonded to it. That is, dihydroxydiphenyl sulfide and its nuclear lower alkyl-substituted products and its nuclear-substituted products. However, other diphenols with sulfur-containing nuclei can also be used. For example, -ol and its substituted products can also be used as starting materials for producing sulfur-containing polyols. In some cases, 2.2. '4.4'
Tri- to tetravalent holifers such as -tetrahydroxydiphenyl sulfide can also be used as starting materials for the production.

The sulfur-containing polyol is preferably a polyol obtained using the above polyphenol as a starting material, particularly a compound obtained using dihydroxydiphenyl sulfide and its substituted product as a starting material. Particularly preferred sulfur-containing polyols are monoepoxide adducts of the above-mentioned polyphenols, and hydrolysates of glycidyl ethers of the above-mentioned polyphenols or oligomers thereof. These two types of sulfur-containing polyols will be explained below.

(9) A sulfur-containing polyol can be obtained by adding a monoepoxide to a polyphenol.

A monoepoxide is a compound having one three-membered cyclic ether group, and includes, for example, alkylene oxide and styrene oxide. The amount added must be at least equivalent to the polyphenol; for example, two or more molecules of monoepoxide should be added to one molecule of diphenol. The number of alcoholic hydroxyl groups in the resulting adduct corresponds to the number of hydroxyl groups in the starting polyphenol, regardless of the addition-11 of the monoepoxide. That is, diols can be obtained from diphenols, and tetraols can be obtained from tetraphenols. Two or more types of monoepoxides can be used, and in that case, a mixture of two or more types of monoepoxides may be added, or different monoepoxides may be added sequentially. The monoepoxide is preferably an alkylene oxide having 2 to 4 carbon atoms,
Particularly preferred are ethylene oxide and propylene oxide. When the divalent or higher residue represented by 2〇〕 is a divalent residue (i.e., when R1 and (10) R2 are not bonding hands), and the monoepoxide is purkylene oxide having 2 to 4 carbon atoms, The resulting sulfur-containing polyol is a compound represented by the following formula [n].

AHOR~0■]2...[111 M is the above-mentioned divalent residue, R is an alkylene group having 2 to 4 carbon atoms, and m is an integer of 1 or more.

+ROi represents the statistical average. That is, for example, m is an integer in one molecule, but in a mixture of compounds with different m, the average value of m is often not an integer. In addition, the addition of alkylene oxide is a sequential reaction and strictly m
It is difficult to obtain a compound in which m is constant, and even a compound where m is 1 often contains a compound where m is 2 or more. Furthermore, +10% is two or more types of + with different R.
May also include RO+. Also, two 16 in one molecule
Ro% may be different. As will be described later, it is not preferable for m to be too large. The average value of m is preferably in the range of 1.0 to 5, particularly 1.0 to 3, and most preferably (11) is about 1.0.

Glycidyl ethers of polyphenols such as bisphenol A and their oligomers are typical epoxy resins. Furthermore, glycidyl ether, which is an alkylene oxide adduct of polyphenol, is also known as an epoxy resin. Hydrolysates of these epoxy resins are well known and are sometimes called phenoxy compounds. Other examples of the sulfur-containing polyol in the present invention are phenoxy compounds similar to the above-mentioned sulfur-containing cores and monoepoxide adducts thereof. That is, polyols obtained by converting the epoxy groups of the above-mentioned polyphenols containing sulfur-containing nuclei or their monoepoxide adducts, glycidyl ethers, or oligomers of the glycidyl ethers into two hydroxyl groups, and monoepoxide additions of limb polyols. is one of the preferred sulfur-containing polyols in the present invention. For example, more preferred examples of such sulfur-containing polyols are compounds represented by the following formula [1nl (12) and alkylene oxide adducts thereof.

... [■] B is the same divalent residue as A above except for the two hydroxyl groups of the diene enol, or the divalent residue of the diol represented by formula (n]
It is a divalent residue with hydroxyl groups removed. n is 0 or 1
is an integer greater than or equal to (7) The alkylene oxide adduct of the compound represented by formula [1] is a compound in which part or all of the alcoholic hydroxyl groups of this compound have been converted to +no%on. As in the above formula [11], n represents a statistical average; for example, the average n may be less than 1. Preferably n is about 0-5, especially about 0-3. Among the compounds represented by the formula [■], a more preferred one is one in which B is a residue of the dienol represented by A above.

In the compounds represented by formula [111 and formula [■], the diphenol residue represented by A is the polyvalent residue represented by formula (13) [I], in which R1 and R2 are the same or different, respectively. It is preferably a lower alkyl group or a halogen atom, where k and 1 are each 0 or 1, and a diphenyl sulfide group. That is, A
is preferably a divalent diphenyl sulfide group, and its lower alkyl substituted products and -.rogen substituted products. The lower alkyl group is an alkyl group having 4 or less carbon atoms, and a methyl group is particularly preferred. The halogen may be chlorine or bromine, with chlorine being preferred from the viewpoint of weather resistance.

Each bond is preferably located at a para position relative to the sulfur atom bonding position. Particularly preferred A is a divalent diphenyl sulfide group having a bond at the para position, that is, the sulfur-containing polyol is a derivative of 414'-dihydroxydiphenyl sulfide.

The sulfur-containing polyol in the present invention has the above formula [11]
The present invention is not limited to the representative compounds represented by the formula [kawa]. For example, there is a compound (14) represented by the following formula [J'] other than those represented by both formulas. A is the divalent residue described above.

AfOR3+0H)p]2 ...[■]R3:p +
Monovalent aliphatic or alicyclic residue p: An integer of 1 or more p is preferably 1, and R3 is preferably a cycloalkylene group or an alkylene group having 8 or less carbon atoms. Still other sulfur-containing polyols include, for example, alkylene oxide adducts of 4,4'-diaminodiphenyl sulfide.

Specific examples of the most preferred sulfur-containing polyols are listed below, but the sulfur-containing polyols in the present invention are not limited to the following.

Bis-C4-(hydroxyethoxy)phenyl sulfide, bis-[4-(2-hydroxypropoxy)phenyl]
Sulfide, Bis-[4-(2,3-dihydroxyprophox(15)cy)phenyl]sulfide, Bis-(4-(4-hydroxycyclohexyloxy)phenylsulfide, Bis-[2-methyl-4-( hydroxyethoxy)-6
-butylphenyl] sulfite, and compounds to which an average of 3 or less molecules of ethylene oxide and/or propylene oxide per hydroxyl group are added.

As the molecular weight of the hydroxyl group of the sulfur-containing polyol increases, the resulting polyurethane synthetic resin tends to have lower hardness and become more flexible. Therefore, unless flexibility is particularly required, it is preferable that the molecular weight of the hydroxyl group is low. The hydroxyl value is well known as a factor indicating the molecular weight of the hydroxyl group, and the hydroxyl value is proportional to the reciprocal of the molecular weight of the hydroxyl group. That is, the lower the hydroxyl value, the higher the molecular weight per hydroxyl group. The hydroxyl value of the sulfur-containing polyol in the present invention is preferably about 100 or more, particularly preferably about 150 to 800. However, even if the sulfur-containing polyol (16) has a lower hydroxyl value than this, it can be combined with an active hydrogen-containing compound that has a lower molecular weight per active hydrogen atom (described below) to lower the average molecular weight of both, making it harder. A polyurethane-based synthetic resin can be produced, so the hydroxyl value is not necessarily limited to the above range. It goes without saying that two or more types of sulfur-containing polyols can be used in combination in the present invention.

The sulfur-containing polyol can be used alone as a polyurethane synthetic resin. However, it can be used in combination with other polyvalent active hydrogen-containing compounds such as polyols and polyamines. The polyvalent active hydrogen-containing compound is a compound having at least two functional groups having active hydrogen atoms that are reactive with isocyanate groups such as alcoholic hydroxyl groups, amino groups, or imino groups. Preferred polyvalent active hydrogen-containing compounds are polyols, but known compounds other than polyols, known in the field of polyurethane chemistry as chain extenders or crosslinkers, particularly polyamines such as diamines, may be used (17). sell. Various compounds can be used as polyols. In particular, polyols having a relatively low average molecular weight per hydroxyl group are preferred. The average molecular weight per hydroxyl group is not particularly limited, but is preferably about 500 or less, particularly about 200 or less. When the polyisocyanate compound remains unchanged, the hardness of the polyurethane synthetic resin tends to increase as the average molecular weight per hydroxyl group in the total of these polyols and the sulfur-containing polyol decreases. Therefore, in order to obtain a hard polyurethane synthetic resin, the average molecular weight per hydroxyl group of the polyol used in combination with the sulfur-containing polyol must be approximately equal to or lower than the average molecular weight per hydroxyl group of the sulfur-containing polyol. preferable. The number of hydroxyl groups in the polyol is suitably 2 to 8, particularly preferably 2 to 4. The proportion of the sulfur-containing polyol needs to be within the range of about 10 to 100% by weight, preferably about 30 to 100% by weight, based on the total of the sulfur-containing polyol and the polyvalent active hydrogen-containing compound. 18) I am in charge of weights. Also, from the point of view of refractive index, especially about 6
A weight ratio of 0 to 100 is preferred. Note that when a polyvalent active hydrogen-containing compound is used in combination with a sulfur-containing polyol, it is not necessarily necessary to use a mixture of both. For example, in the case of production using the prepolymer method, a prepolymer is produced from a sulfur-containing polyol and a non-yellowing polyisocyanate compound, and this prepolymer is cured with a polyvalent active hydrogen-containing compound to produce a polyurethane synthetic resin. be able to.

The above polyols that can be used in combination include polyhydric alcohols,
These include poly(oxy7 alkylene) diols, other polyether polyols, polyester polyols, and other polyols. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, neopentyl glycol, glycerin, trimethylolpropane, 1,4-cyclohexanediol, tricyclo[5,2,1,O''
・6] Decane dimetatool, 1.2.6 (19) Monocyclohexanetriol, dibromoneopentyl glycol, etc. Examples of poly(oxyalkylene) diols include hashethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like.

As polyether polyols, the above polyhydric alcohols,
poly(oxyalkylene glycol), polyhydric phenol (e.g. bisphenol A), alkanolamine,
There are compounds obtained by adding the above-mentioned monoepoxides (especially ethylene oxide and propylene oxide) to polyamines and the like. Examples of polyester polyols include polyester polyols having residues of adipic acid, phthalic acid, isophthalic acid, and other polyhydric carboxylic acids and polyhydric alcohol residues as described above. Of course, two or more of these polyols can also be used in combination.

The polyisocyanate compounds can be broadly divided into non-yellowing polyisocyanates and yellowing polyisocyanates (20). As mentioned above, the polyisocyanate compounds in the present invention are preferably non-yellowing polyisocyanates. The non-yellowing polyisocyanate is a polyisocyanate compound that does not contain an incyanate group directly bonded to an aromatic nucleus, and may also be a compound having an aromatic nucleus as described below. Yellowing polyisocyanates are aromatic polyisocyanate compounds containing in7anate groups directly bonded to aromatic nuclei. As mentioned above, aromatic nuclei are effective in improving the refractive index of polyurethane synthetic resins. Therefore, the polyisocyanate compound is preferably a compound having an aromatic nucleus.

On the other hand, yellowing polyinsyanate is easily yellowed by ultraviolet rays and is therefore difficult to use for optical elements exposed to ultraviolet rays. Therefore, the most preferred polyisocyanate compound is a non-yellowing polyisocyanate having an aromatic nucleus.

As a non-yellowing polyisocyanate having an aromatic nucleus,
Examples include xylylene diisocyanate and tetramethylxylylene diisocyanate (21). Non-yellowing polyisocyanates without aromatic nuclei include aliphatic polyisocyanates and alicyclic polyisocyanates, such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, cyfchlorohexylmethyl diisocyanate, Examples include bis(isocyanatomethyl)cyclohexane. Furthermore, yellowing polyisocyanates that may be used in some cases include tolylene diisocyanate, diphenylmethane diincyanate, polymethylene polyphenylisocyanate, and naphthalene diisocyanate. The polyisocyanate compound may also be a modified polyisocyanate as described above, such as a prepolymer type modified product, a carbodiimide modified product, a urea modified product, a billet modified product, an isocyanurate modified product, and the like. Two or more of these polyisocyanate compounds can also be used in combination. The amount of polyincyanate compound used is sulfur-containing compound (22
) When a diol and the above-mentioned polyvalent active hydrogen compound are used in combination, the appropriate amount is about 0.9 to 1.2 volume per equivalent of the total of the diol and the sulfur-containing polyol, particularly about 0.9 to 0.95 to 1.2.
1.1 equivalents are preferred.

The polyurethane synthetic resin of the present invention is produced using various auxiliary raw materials in addition to the above-mentioned main raw materials. Auxiliary raw material 1
One is the catalyst. It is said that a catalyst is often required especially when the reaction proceeds gradually in the casting method etc. described below.
Catalysts are often used to promote the polyurethane forming reaction. As the catalyst, those known in the field of polyurethane chemistry can be used, and representative catalysts include tertiary amine catalysts and organometallic compound catalysts. Examples of the former include triethylenediamine, triethylamine, N-
Examples of the latter include dibutyltin dilaurate, stannath octoate, and other organotin compounds. Other auxiliary raw materials include, for example, stabilizers such as ultraviolet absorbers, light stabilizers, and antioxidants, and anti-coloring agents, which may be used in combination with the main raw material if necessary (23). Further, a coloring agent such as a dye may be added to the eyeglass lens. Of course, dyeing can be carried out after the spectacle lens is molded as is commonly done.

The manufacturing method and molding method of the polyurethane synthetic resin are not particularly limited. The polyurethane synthetic resins used in the present invention can be roughly divided into two types: those having thermoplasticity and those having no thermoplasticity (hereinafter referred to as thermosetting). The former thermoplastic polyurethane synthetic resin is obtained using substantially divalent raw materials. That is, when a sulfur-containing diol, a non-yellowing diisocyanate compound, and a polyvalent active hydrogen compound are used together, it is obtained by reacting a divalent compound (for example, a diol such as a dihydric alcohol). however,
A small amount of polyurethane from which trivalent or higher valent compounds can be obtained as a small portion of the raw materials may be used in combination so long as the thermoplasticity is not lost. Thermosetting polyurethane synthetic resins are obtained by using trivalent or higher valent compounds as part of the raw materials. A trivalent or higher valent compound may be used in combination with a divalent compound (24), for example, a combination of a tetravalent sulfur-containing polyol and a divalent sulfur-containing polyol, or a divalent sulfur-containing polyol and a trivalent or higher valent polyol. A thermosetting polyurethane synthetic resin can also be obtained by using a polyol other than the sulfur-containing polyol in combination. However, thermosetting polyurethane synthetic resin is a term commonly used in the field of polyurethane chemistry, and refers to a three-dimensional network polymer that does not necessarily require curing with heat. Molding methods that can be commonly applied to thermoplastic polyurethane synthetic resins and thermosetting polyurethane synthetic resins are cast molding methods and R-M molding methods. The cast molding method is a method in which a raw material mixture is injected into a predetermined mold and then heated, etc. to harden and mold. Although it is inferior to the R-M method and the injection molding method described below in terms of productivity, A molded product with little molding distortion and good optical performance can be obtained. The RIM method, or reaction injection molding method, improves productivity (25
) is the most expensive method. On the other hand, in the case of thermoplastic polyurethane synthetic resin, secondary molding methods such as injection molding methods can be applied. For example, molding can be carried out by injection molding using granular or powder molding materials of thermoplastic polyurethane synthetic resin obtained by various methods.

The injection molding method is a highly productive method and has fewer restrictions such as molding conditions than the R/M molding method. The molding method for optical elements is not limited to these methods; for example, optical elements can be manufactured by processing blocks or sheets of polyurethane synthetic resin, and in the case of thermoplastic polyurethane synthetic resin, pressing methods can also be applied. It is possible. In addition to the molding method, various methods for forming polyurethane from raw materials can be employed, such as a one-shot method, a prepolymer method, and a quasi-prepolymer method.

Lenses are particularly suitable as the optical element of the present invention, including spherical lenses, aspheric lenses, irregular lenses, and 7-Lesnel lenses.

(26) Although it is particularly preferable to use it for eyeglasses, it can also be used for various optical devices as described above. Further, the optical element is not limited to a lens, but may also be a diffraction grating, a prism, or other elements.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

The physical properties were measured using the following method.

Refractive index: refractive index Y for light with a wavelength of 589.3 nm at 20° C.: Yellow index (represents the degree of coloring). Measured values using color computer SM2 model manufactured by Suga Test Instruments.

Haze: (represents the degree of transparency) Measured value using a haze meter manufactured by Suga Test Instruments ■.

Example 1 306 parts (by weight, the same applies below) of bis-(4-(hydroxyethoxy)phenyl) sulfide, 188 parts of xylylene diisocyanate, 2 parts of dibuty(27)tin dilaurate, and 4000 parts of chlorobenzene
1 part was placed in a four-eye flask equipped with a reflux condenser and a stirrer, and heated at 80°C for 1 hour in a nitrogen stream, and 13 hours.
Heated at 0°C for 4 hours. After the reaction was completed, the contents were poured into a large amount of methanol, and the resulting precipitate was reprecipitated with a dimethylformamide-methanol mixture, and the molecular weight was approximately 24.
407 parts of a white thermoplastic polyurethane synthetic resin was obtained. When this synthetic resin was molded into a lens with an outer diameter of 55 mm by injection molding, it was extremely transparent and had the physical properties shown in Table 1.
In addition, a lens with a high refractive index and little coloring was obtained.

Example 2 75 parts of a diol with a hydroxyl value of 286 consisting of a propylene oxide adduct of 4.4'-thiodiphenol, bis-[
36 parts of 4-(2,s-dihydroxypropoxy)phenyl]sulfide, 85 parts of isophorone diisocyanate,
and dibutyltin dilaurate to the above total amount.
.

(28) After adding the amount of ppm and heating and mixing, the mixture was poured into a mold made up of two glass lens molds whose surfaces had been treated with a release agent in advance and a fluororesin gasket. Then 80
C. for 4 hours, followed by heating at 100.degree. C. for 48 hours in a hot air oven to cure. Table 1 shows the properties of the obtained lens.

Example 3 Bis-(: 4-(2,3-dihydroxybroboxy7)
phenyl]sulfide 180 parts, tricyclo[5,2,
A lens was manufactured in the same manner as in Example 2 using 20 parts of Deforcen Dimethator, 265 parts of tetramethylxylylene diisocyanate, and 100 ppm of dibutyltin dilaurate. The physical properties are shown in Table 1.

Example 4 300 parts of bis-C4-(hydroxyethoxy)phenyl]sulfide, 100 parts of a highly branched polyester polyol with a hydroxyl value of 275 (Kemirafu, Werke, Huels, trade name "Oxyborie (29) Stell V-2922'), A lens was manufactured in the same manner as in Example 2 using 272 parts of dicyclohexylmethane diisocyanate and 100 ppm of dibutyltin dilauret.The physical properties are shown in Table 1.

Example 5 306 parts of bis-C4-(hydroxyethoxy)phenyl]sulfide, hydroxypivalic acid-neobentyl glycol ester diol (BASF
A lens was manufactured in the same manner as in Example 2 using 204 parts of Japan Co., Ltd. (trade name - HPli''), 444 parts of isophorone diisocyanate), and 1100 pp of dibutyltin dilaurate.The physical properties are shown in Table 1.

Example 6 314 parts of bis-(4-(2-hydroxypropoxyS/)phenyl]sulfide, 6 parts of bis-[4-(2,3-dihydroxypropoxy)phenyl]sulfide)"3h, 4.4'- 75 parts of diphenylmethane diisocyanate and dibutyltin silica (30) urate were added in an amount of 50 ppm,!: based on the above total amount, mixed with heat, poured into the same mold as in Example 2, and heated at 100°C for 6 hours. It was heated and cured at 120° C. for 48 hours.The physical properties of the obtained lens are shown in Table 1.

Example 7 An epoxy resin with an epoxy oxygen content of 95% obtained by the reaction of 4.4'-thiodiphenol and epichlorohydrin was hydrolyzed to obtain a polyol compound with a hydroxyl value of 583.

Silens was obtained in the same manner as in Example 2 using 100 parts of this polyol compound, 127 parts of tetramethylxylylene diisocyanate, and 120 ppm of dibutyltin dilaurate. The physical properties are shown in Table 1.

Example 8 The same procedure as in Example 2 was carried out using 375 parts of bis-[5-chloro-2-(hydroxyethoxy)phenyl]sulfide, 244 parts of tetramethylxylylene diisocyanate, and 200 ppm of dibutyltin dilaurate (31). Silens was obtained by the method. The physical properties are shown in Table 1.

Comparative Example 1 Bis-[4-hydroxyethoxyphenyl] of Example 1
Example 1 by replacing the sulfide with 316 parts of 2'-bis-[4-hydroxyethoxyphenyl]propane.
I gave it back. The refractive index of the obtained lens was only 1.574, which was 1.6 OB when using a sulfur-containing compound.
The value was significantly lower than that of .

Comparative Example 2 100 parts of 2.2-bix-(4-7!J-ruoxycarbonyloxyethoxy-2,45,6-titrabromophenyl)propane and 55 parts of diisopropyl peroxydicarbonate were mixed, Pour into a mold assembled with a glass lens mold and a fluororesin gasket, and
When the temperature was gradually increased from 120° C. to 120° C. and the material was cured for 18 hours, a yellow lens with a Y and a strength of 4.5 was obtained. The refractive index of this lens was as high as 1.610 (32), but the specific gravity #i was 1.58, which was significantly heavier than the lens of the present invention.

Table 1 (33)

Claims (1)

[Claims] 1. A sulfur-containing polyol containing a divalent or higher residue represented by the following formula [11] and two or more alcoholic hydroxyl groups, or a sulfur-containing polyol in which the proportion of the sulfur-containing polyol is at least 10
An optical element made of a polyurethane synthetic resin obtained by reacting a combination of the sulfur-containing thread polyol, which is a weight factor, with another polyvalent active hydrogen-containing compound, and a polyisocyanate compound. However, Hl, R1: the same or different lower alkyl group, halogen atom, or bond, 1: 0, 1, respectively. Alternatively, 2 (1) Z The optical element according to claim 1, wherein the sulfur-containing polyol is a sulfur-containing diol represented by the following formula [■]. HOR~oH] [■] Mu: Divalent residue represented by formula [1] R: Alkylene group having 2 to 4 carbon atoms m: Integer 5 of 1 or more The sulfur-containing polyol is as follows The optical element according to claim 1, which is a sulfur-containing polyol represented by formula [1[1]. ...[■] B: Divalent residue represented by formula [11, or formula (11
Residue n of the sulfur-containing diol with two hydroxyl groups removed: 0 or an integer of 1 or more