JP4341061B2 - Plastic lens - Google Patents

Description

【００３７】
【表２】

【００３８】
表１及び表２において用いた略号の意味は以下の通りである。
ＨＤＩ ：ヘキサメチレンジイソシアネート
ＴＭＰ ：トリメチロールプロパン
ＰＥＴＭＡ：ペンタエリスリトールテトラキス（メルカプトアセテート）
ｍ−ＭＸＴ：１，３−ビス（メルカプトメチル）ベンゼン
ＤＢＴＤＬ：ジブチルチンジラウレート
【００３９】
【発明の効果】
本発明によって得られたプラスチックレンズは、屈折率、耐熱性、耐湿性、耐衝撃性に優れ、眼鏡レンズ、カメラレンズ及びその他の光学素子に好適である。また、脱泡が容易であることから、光学素子に好適なプラスチックレンズの生産性が著しく向上した。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic lens comprising an organic polyisocyanate containing an allophanate-modified product of hexamethylene diisocyanate and a mercapto group-containing compound, and a method for producing the same.
[0002]
[Prior art]
Plastic lenses are widely used because they are advantageous in terms of lightness, safety, moldability, and the like as compared with inorganic glass lenses. In particular, polydiethylene glycol bisallyl carbonate (CR-39) has been widely used in spectacle lenses. However, since CR-39 has a low refractive index, there is a drawback that the lens becomes thick. Therefore, various proposals for increasing the refractive index of plastic lenses have been made. For example, a polythiourethane resin obtained by reacting an aromatic polyisocyanate compound and a polythiol compound described in JP-A-63-46213 has been widely used because of its high refractive index. It is coming.
[0003]
[Problems to be solved by the invention]
However, the methods disclosed in JP-A-55-13747 and JP-A-63-23908 have limitations in increasing the refractive index of plastic lenses, and the water resistance and impact resistance are insufficient.
[0004]
The plastic lens described in Japanese Patent Laid-Open No. 63-46213 uses a polythiourethane resin having a good refractive index. However, since the polythiourethane resin has insufficient moisture resistance, the lens may become clouded or deformed due to water absorption after long-term use, and the impact resistance is insufficient.
[0005]
As a means for improving the impact resistance of a plastic lens, there are a method using a polythiourethane resin composed of an alicyclic isocyanate and a polyfunctional polythiol, and a method using a polyurethane resin using an isocyanurate modified product of an aliphatic isocyanate. Proposed. However, since the isocyanurate-modified product has a high viscosity, there is a problem of poor production efficiency that it takes time to remove bubbles (so-called “defoaming”) mixed in the production of the plastic lens. It was insufficient.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have improved the above-mentioned drawbacks by using specific organic polyisocyanates, etc., and are easy to defoam, so that production efficiency is good, and refractive index / heat resistance -A plastic lens having excellent moisture resistance and impact resistance and good curability, and a manufacturing method thereof have been found.
[0008]
That is, the present invention relates to a plastic lens obtained from a composition having (A) an organic polyisocyanate, and (B) a compound having two or more mercapto groups.
The organic polyisocyanate of (A) contains an allophanate-modified product composed of hexamethylene diisocyanate and an aliphatic monool having 1 to 6 carbon atoms, and the viscosity of the modified product at 25 ° C. is 500 mPa · s or less. ,
The compound having two or more active hydrogen groups in (B) is pentaerythritol tetrakis (mercaptoacetate) and / or 1,3-bis (mercaptomethyl) benzene,
(A) The mixing ratio of the organic polyisocyanate and (B) the compound having two or more mercapto groups is such that the ratio of isocyanate group / active hydrogen group is 0.9 to 1.2,
It is a plastic lens characterized by.
[0009]
The present invention is a method for producing a plastic lens, which comprises injecting a composition having the above (A) and (B) into a mold and heating and curing the composition.
[0010]
The greatest feature of the present invention is that (A) an organic polyisocyanate containing an allophanate modified product of HDI and having a viscosity at 25 ° C. of 500 mPa · s or less is used as the organic polyisocyanate. . The inventors of the present invention have improved productivity by easily defoaming bubbles that are mixed in the production of plastic lenses, and have almost the same refractive index, heat resistance, moisture resistance, and impact resistance as before. The present inventors have invented a good plastic lens and a method for manufacturing the same that sufficiently satisfy the required performance.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in more detail. The organic polyisocyanate (A) used in the present invention is mainly composed of an HDI monoallophanate-modified product having a viscosity at 25 ° C. of 500 mPa · s or less. When the viscosity at 25 ° C. exceeds 500 mPa · s, problems such as an increase in the time required for defoaming tend to occur.
[0012]
As a method for producing this allophanate-modified product of HDI, an aliphatic monool (a) having 1 to 6 carbon atoms and an organic diisocyanate (b) are mixed with an isocyanate group at 70 to 150 ° C. in the presence of an allophanate catalyst (c). Is reacted to 1.9 to 2.1 moles of the hydroxyl group, and when the predetermined reaction rate is reached, the catalyst poison (d) is added to stop the reaction. More preferably, the residual monomer is removed by distillation or extraction. It is a method of removing.
[0013]
The C1-C6 aliphatic monool (a) used in the present invention is a compound having one alcoholic hydroxyl group in the molecule, and specifically includes methanol, ethanol, propanol (various isomers). ), Butanol (including various isomers), propanol (including various isomers), and hexanol (including various isomers).
[0014]
The organic polyisocyanate used at the time of the allophanate reaction is mainly composed of polyol, polythiol, hydroxythiol, thioether polyol and HDI having a number average molecular weight of 62 to 1,000, preferably 62 to 500, which will be described later, in addition to a pure monomer of HDI. An isocyanate group-terminated prepolymer obtained by reacting an organic polyisocyanate can also be used. These may be used alone or in combination of two or more. Moreover, you may use organic polyisocyanate other than HDI together.
[0015]
Other organic polyisocyanates that can be used in combination include 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4, 4'-diphenylpropane diisocyanate, o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene Socyanate, aromatic diisocyanate such as 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, aliphatic diisocyanate such as 1,4-tetramethylene diisocyanate, lysine diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p- Examples include alicyclic diisocyanates such as xylene diisocyanate and tetramethylxylene diisocyanate, hydrogenated xylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate. Also, so-called modified organic polyisocyanates such as adduct-modified products, burette-modified products, isocyanurate-modified products, uretonimine-modified products, uretdione-modified products, and carbodiimide-modified products of these organic diisocyanates can be used. Furthermore, what is called a polymeric body like polyphenylene polymethylene polyisocyanate, crude toluene diisocyanate, etc. can also be used. These organic polyisocyanates can be used alone or in a mixture of two or more. These organic polyisocyanates may be mixed with HDI and then subjected to an allophanatization reaction, or may be mixed with an allophanate-modified product of HDI.
[0016]
As an allophanatization catalyst (c) used for this invention, the metal salt of organic carboxylic acid is mentioned. Examples of the organic carboxylic acid include acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-ethylhexanoic acid and other saturated aliphatic carboxylic acids, cyclohexanecarboxylic acid A saturated alicyclic carboxylic acid such as cyclopentanecarboxylic acid, a saturated bicyclic carboxylic acid such as bicyclo (4.4.0) decane-2-carboxylic acid, a mixture of the above carboxylic acids such as naphthenic acid, oleic acid, Examples thereof include unsaturated aliphatic carboxylic acids such as linoleic acid, linolenic acid, soybean oil fatty acid and tall oil fatty acid, aromatic aliphatic carboxylic acids such as diphenylacetic acid, and aromatic carboxylic acids such as benzoic acid and toluic acid. Examples of the metal constituting the metal salt of the carboxylic acid include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium, calcium and barium, manganese, iron, cobalt, nickel, copper, zinc and zirconium Transition metals, boron groups such as aluminum, and carbon group metals such as tin and lead. Among these, metal salts of alkylcarboxylic acid such as zirconium, zinc and lead are preferable, and zirconium salts of alkylcarboxylic acid are particularly preferable.
[0017]
Examples of the catalyst poison (d) used in the present invention include inorganic acids such as phosphoric acid and hydrochloric acid, organic acids having a sulfonic acid group, a sulfamic acid group, and the like, and esters thereof and acyl halides.
[0018]
Further, the allophanate-modified organic polyisocyanate thus obtained is reacted with an active hydrogen group-containing compound to be partially thiourethanized or urethanized and used as the component (A) in the present invention.
[0019]
When the active hydrogen group-containing compound is introduced into (A) by the method as described above, the active hydrogen group-containing compound preferably has 2 functional groups. When the number of functional groups is less than 2, the number of functional groups of the obtained organic polyisocyanate becomes small. For this reason, the crosslink density in the polyurethane-based resin at the time of lens molding becomes small, and the physical properties tend to be lowered. When the number of functional groups exceeds 2, gelation tends to occur during the reaction.
[0020]
Specific examples of the active hydrogen-containing compound include 1,2-propanediol (hereinafter abbreviated as “1,2PD”), 1,2-butanediol (hereinafter abbreviated as “1,2BD”), 1,3 butanediol. (Hereinafter abbreviated as “1,3-BD”), 2-methylpentanediol (hereinafter abbreviated as “2-MPD”), 3-methylpentanediol (hereinafter abbreviated as “3-MPD”), neopentyl glycol (hereinafter abbreviated) "NPG"), 2,2-diethyl-1,3-propanediol (hereinafter abbreviated as "DEPD"), 2-butyl-2-ethyl-1,3-propanediol (hereinafter abbreviated as "BEPD") 2,2,4-trimethyl-1,3-pentanediol (hereinafter abbreviated as “TMPD”), 2-ethyl-1,3-hexanediol (hereinafter abbreviated as “EHD”), 1,2-bis (hydroxy) Methyl) benzene, 1,3- (Hydroxymethyl) benzene, 1,4-bis (hydroxymethyl) benzene, 1,2-bis (hydroxyethyl) benzene, 1,3-bis (hydroxyethyl) benzene, 1,4-bis (hydroxyethyl) benzene Bisphenol A, bisphenol F, bisphenol S, alkylene oxide adduct of bisphenol A, alkylene oxide adduct of bisphenol F, alkylene oxide adduct of bisphenol S, tetrakis (mercaptomethyl) methane, diethylene glycol bis (3-mercaptopropionate ), Trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), 1,2-bis (1′-mercaptomethylthio) -3-mer Captopropane, 1,2-bis (1′-mercaptoethylthio) -3-mercaptopropane (hereinafter abbreviated as “BMETMP”), 1,2,3-tris (1′-mercaptomethylthio) propane, 1,2, 3-tris (1′-mercaptomethylthio) propane (hereinafter abbreviated as “TMETP”), 1,2,3-tris (3′-mercaptopropylthio) propane, thioglycerol, dithioglycerol, dimercaptopropanol, pentaerythritol tetrakis (Mercaptoacetate) (hereinafter abbreviated as “PETMA”) and 1,3-bis (mercaptomethyl) benzene (hereinafter abbreviated as “m-MXT”).
[0021]
The compound (B) having two or more mercapto groups used in the present invention is specifically pentaerythritol tetrakis (mercaptoacetate), 1,3-bis (mercaptomethyl) benzene alone or a mixture thereof.
[0023]
Furthermore, use of PETMA or m-MXT is particularly preferable because a lens having a high refractive index can be obtained.
[0024]
The plastic lens is molded by combining (A) an organic polyisocyanate, (B) a mercapto group-containing compound, and, if necessary, a urethanization catalyst and additives, defoaming as necessary, and glass or metal. A known cast molding method such as a method of injecting into a mold in which a mold made of resin and a resin gasket are combined and heat-curing can be used. In addition, in order to make it easy to take out a molded product at the time of mixing raw materials, the mold may be treated with a release agent, or a release agent may be mixed in (A) and / or (B).
[0025]
The mixing ratio of the (A) organic polyisocyanate and the (B) mercapto group-containing compound is such that the ratio of isocyanate group / mercapto group is in the range of 0.9 to 1.2, particularly in the range of 0.92 to 1.18. preferable. When the ratio of isocyanate group / mercapto group is outside the range of 0.9 to 1.2, the amount of polymerized and crosslinked structure introduced is insufficient, and a plastic lens having the high physical properties intended by the present invention can be obtained. Absent.
[0026]
The reaction time and reaction temperature are 20 to 150 ° C for 0.5 to 72 hours, preferably 30 to 130 ° C for 1 to 50 hours. The reaction may be a one-stage reaction or a multi-stage reaction of two or more stages, but a multi-stage reaction is preferable in consideration of a thermal history and the like. If the reaction temperature or reaction time exceeds the upper limit, problems such as coloration occur on the lens, which is not preferable for a plastic lens.
[0027]
Examples of the urethanization catalyst that can be used in the present invention include known ones such as dibutyltin dilaurate, dimethyltin dichloride, organometallic salts such as bismuth stearate and bismuth oleate, and tertiary amines such as triethylamine and triethylenediamine. It is done.
[0028]
Additives that can be used in the present invention include ultraviolet absorbers, antioxidants, anti-coloring agents, fluorescent dyes, dispersible dyes, lubricants, surfactants, and the like.
[0029]
【Example】
The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “%” means “% by mass”.
[0030]
The refractive index, heat resistance, moisture resistance, and impact resistance of the resins obtained in Examples and Comparative Examples were determined by the following test methods.
Refractive index: Measured at 20 ° C. using a Purfrich refractometer.
Moisture resistance: A molded product having a diameter of 70 mm and a thickness of 2 mm was immersed in warm water at 85 ° C., and the water absorption after 1 hour, 100 hours and 150 hours was measured.
Impact resistance: The height (cm) at which 50% of the sample was broken by a DuPont impact tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) with a sample size of 3.5 × 3.5 cm and a weight of 300 g. .
Heat resistance: The obtained lens was heated at 90 ° C. for 1 week, and the impact resistance was measured by the same method as described above.
In addition, in order to confirm the productivity of the plastic lens when obtaining the resin in the examples and comparative examples, the time required from the start of mixing at room temperature to the complete defoaming of the mixed solution (hereinafter referred to as “defoaming”) Time was abbreviated as “)”.
[0031]
(Synthesis of modified HDI allophanate)
Synthesis example 1
A reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube was charged with 950 g of HDI, 50 g of isopropanol, 0.006 g of zirconium 2-ethylhexanoate, and 110 ° C. under a nitrogen atmosphere. Was reacted for 3 hours, and when the isocyanate content reached 41%, 0.2 g of phosphoric acid was added as a catalyst poison, and the mixture was further stirred for 2 hours. The obtained reaction solution was subjected to thin-film distillation at 150 ° C. and 0.7 kPa to remove unreacted HDI, thereby obtaining an allophanate-modified product of HDI. This is designated isocyanate A. Isocyanate A had a viscosity of 100 mPa · s at 25 ° C. and an isocyanate content of 19.3%.
[0032]
Synthesis example 2
In an apparatus similar to Synthesis Example 1, 900 g of HDI, 100 g of tridecanol, 0.006 g of zirconium 2-ethylhexanoate were added, and the mixture was reacted at 110 ° C. for 3 hours in a nitrogen atmosphere. The isocyanate content was 41%. Then, 0.2 g of phosphoric acid was added as a catalyst poison, and the mixture was further stirred for 2 hours. The obtained reaction solution was subjected to thin-film distillation at 150 ° C. and 0.7 kPa to remove unreacted HDI, thereby obtaining an allophanate-modified product of HDI. This is designated Isocyanate B. Isocyanate B had a viscosity at 25 ° C. of 180 mPa · s and an isocyanate content of 14.6%.
[0033]
Comparative Synthesis Example To the same apparatus as in Synthesis Example 1, 2,000 g of HDI was charged, 32 g of 1,3-butanediol was added, and the reaction was performed at 55 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, 0.10 g of potassium 2-ethylhexanoate was added and reacted at 55 ° C. for 2 hours under a nitrogen atmosphere. When the isocyanate content reached 42%, 0.06 g of phosphoric acid was added as a catalyst poison. The mixture was further stirred for 2 hours. The obtained reaction solution was subjected to thin-film distillation at 150 ° C. and 0.7 kPa to remove unreacted HDI, thereby obtaining an isocyanurate-modified product of HDI. This is designated isocyanate C. Isocyanate C had a viscosity at 25 ° C. of 2,500 mPa · s and an isocyanate content of 21.2%.
[0034]
Example 2
After mixing and homogenizing 100 g of isocyanate A and 49.6 g of PETMA at room temperature, the mixture was poured into a mold composed of a glass mold treated with a silicon baking type mold release agent and a Teflon (registered trademark) gasket. After the injection, it was cured by heating at 40 ° C. for 3 hours, 60 ° C. for 2 hours, 80 ° C. for 2 hours, and 100 ° C. for 2 hours. Table 1 shows the defoaming time and the refractive index, moisture resistance, impact resistance, and heat resistance of the obtained lens.
[0035]
Examples 3 , 5 , 6 and Comparative Examples 1-6
A plastic lens was obtained in the same manner as in Example 2 using the raw materials shown in Table 1. Table 1 shows the characteristics of the obtained lens, and Table 2 shows a comparative example.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
The meanings of the abbreviations used in Tables 1 and 2 are as follows.
HDI: hexamethylene diisocyanate TMP: trimethylolpropane PETMA: pentaerythritol tetrakis (mercaptoacetate)
m-MXT: 1,3-bis (mercaptomethyl) benzene DBTDL: dibutyltin dilaurate
【The invention's effect】
The plastic lens obtained by the present invention is excellent in refractive index, heat resistance, moisture resistance and impact resistance, and is suitable for eyeglass lenses, camera lenses and other optical elements. Further, since the defoaming is easy, the productivity of a plastic lens suitable for an optical element is remarkably improved.

Claims (2)

In a plastic lens obtained from a composition having (A) an organic polyisocyanate, and (B) a compound having two or more mercapto groups,
The organic polyisocyanate of (A) contains an allophanate-modified product composed of hexamethylene diisocyanate and an aliphatic monool having 1 to 6 carbon atoms, and the viscosity of the modified product at 25 ° C. is 500 mPa · s or less. ,
The compound having two or more active hydrogen groups in (B) is pentaerythritol tetrakis (mercaptoacetate) and / or 1,3-bis (mercaptomethyl) benzene,
(A) The mixing ratio of the organic polyisocyanate and (B) the compound having two or more mercapto groups is such that the ratio of isocyanate group / active hydrogen group is 0.9 to 1.2,
Plastic lens characterized by Injecting the composition of claim 1 into a mold and heating and curing the composition;
A method for producing a plastic lens.