JP2003322701A - Plastic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic lens having excellent refractive index, heat resistance, moisture resistance and shock resistance, having easy defoaming property which results in a high production efficiency, and having favorable curing property, and to provide a method of manufacturing the lens. <P>SOLUTION: In the plastic lens obtained from a composition comprising (A) organic polyisocyanate and (B) a compound having two or more active hydroxyl groups, the organic polyisocyanate (A) contains an allophanate modified product of hexamethylene diisocyanate and the viscosity of the modified product at 25°C is ≤500 mPa×s. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plastic lens comprising an organic polyisocyanate containing an allophanate-modified hexamethylene diisocyanate and an active hydrogen group-containing compound, and a method for producing the same.

[0002]

2. Description of the Related Art Plastic lenses are widely used because they are advantageous in lightness, safety, moldability, etc., as compared with lenses made of inorganic glass. Particularly in spectacle lenses, polydiethylene glycol bisallyl carbonate (CR-39) and the like have been widely used. But CR
Since -39 has a low refractive index, it has a drawback that the lens becomes thick. Therefore, various proposals for increasing the refractive index of plastic lenses have been made. For example, JP-A-63-46
The polythiourethane resin obtained by reacting an aromatic polyisocyanate compound and a polythiol compound described in Japanese Patent No. 213 has been widely used because of its high refractive index.

[0003]

However, in the methods disclosed in JP-A-55-13747 and JP-A-63-23908, there is a limit to increase the refractive index of the plastic lens, and water resistance and The impact resistance was also insufficient.

The plastic lens described in JP-A-63-46213 uses a polythiourethane resin having a high refractive index. However, since the polythiourethane resin does not have sufficient moisture resistance, the lens may become cloudy or deform due to water absorption after long-term use.
Moreover, the impact resistance was also insufficient.

As a means for improving the impact resistance of a plastic lens, a method using a polythiourethane resin composed of an alicyclic isocyanate and a polyfunctional polythiol, or a polyurethane resin using an isocyanurate modified product of an aliphatic isocyanate is used. The method used is proposed. However, since the modified isocyanurate has a high viscosity,
There is a problem of poor production efficiency that it takes time to remove air bubbles mixed in during the production of a plastic lens (so-called "defoaming"), which is still insufficient in practical use.

[0006]

As a result of intensive studies, the present inventors have improved the above-mentioned drawbacks by using a specific organic polyisocyanate, etc. We have found a plastic lens that is good and has excellent refractive index, heat resistance, moisture resistance, and impact resistance, and has good curability, and a method for manufacturing the same.

That is, the present invention provides a plastic lens obtained from a composition comprising (A) an organic polyisocyanate and (B) a compound having two or more active hydrogen groups, wherein (A) is hexamethylene diisocyanate (hereinafter Abbreviated as "HDI") and has a viscosity at 25 ° C. of 500
It is a plastic lens characterized by having mPa · s or less.

The present invention is the plastic lens characterized in that the active hydrogen group in the above (B) is selected from a hydroxyl group and a mercapto group.

The present invention is a method for producing a plastic lens, which comprises injecting the composition having (A) and (B) into a mold and heating the composition to cure the composition.

The greatest feature of the present invention is that (A) an organic polyisocyanate contains a modified product of HDI allophanate, and the modified product has a viscosity at 25 ° C. of 500.
It is to use an organic polyisocyanate of mPa · s or less. The present inventors have improved productivity by easily defoaming bubbles mixed in when manufacturing a plastic lens, and have a refractive index
The inventors have invented a good plastic lens that sufficiently satisfies the required performances such as heat resistance, humidity resistance, and impact resistance, and a method for manufacturing the same.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail. The (A) organic polyisocyanate used in the present invention is 25
HDI whose viscosity at ℃ is less than 500mPa · s
The main component is the modified mono-allophanate of. If the viscosity at 25 ° C. exceeds 500 mPa · s, problems such as a longer defoaming time tend to occur.

The HDI allophanate-modified product can be produced by subjecting a monool (a) having 1 to 10 carbon atoms and an organic diisocyanate (b) to an isocyanate at 70 to 150 ° C. in the presence of an allophanatization catalyst (c). The group is reacted up to 1.9 to 2.1 times the molar amount of the hydroxyl group, and when the reaction rate reaches a predetermined level, the catalyst poison (d) is added to stop the reaction, and more preferably, the residual monomer is removed by distillation or extraction. Is the method of removing.

The monool (a) having 1 to 10 carbon atoms used in the present invention is a compound having one alcoholic hydroxyl group in the molecule, and specifically, methanol, ethanol, propanol (various isomers). , Butanol (including various isomers), propanol (including various isomers), hexanol (including various isomers), heptanol (including various isomers), octanol (including various isomers), nonanol Aliphatic monools (including various isomers), decanol (including various isomers), cyclohexanol, methyl-cyclohexanol (including various isomers), alicyclic monools such as alkyl-substituted cyclohexanol , Benzyl alcohol, aromatic monools such as alkyl-substituted benzyl alcohol, ethylene glycol monomethy Ether, mono-ols such as propylene glycol monomethyl ether, hydroxyacetic acid, carboxylic acid-based mono-ol such as hydroxypropionic acid, hydroxyacetic acid ester, ester mono-ols such as hydroxypropionic acid ester, etc. can be mentioned. Preferred (a) in the present invention is an aliphatic monool having 1 to 6 carbon atoms.

The organic polyisocyanate used in the allophanate reaction is, in addition to a pure HDI monomer, a number average molecular weight of 62 to 1,000, preferably 62 to 50, which will be described later.
0 polyol, polythiol, hydroxythiol,
An isocyanate group-terminated prepolymer obtained by reacting a thioether polyol and an organic polyisocyanate containing HDI as a main component can also be used. These alone,
You may use it in mixture of 2 or more types. Moreover, you may use together organic polyisocyanate other than HDI.

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, 4,4'-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 diisocyanate, 3 ，
Aromatic diisocyanates such as 3'-dimethoxydiphenyl-4,4'-diisocyanate, 1,4-tetramethylene diisocyanate, aliphatic diisocyanates such as lysine diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, tetra There are alicyclic diisocyanates such as araliphatic diisocyanates such as methyl xylene diisocyanate, hydrogenated xylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated diphenylmethane diisocyanate and hydrogenated tetramethyl xylene diisocyanate. In addition, modified adducts of these organic diisocyanates,
So-called modified organic polyisocyanates such as buret modified products, isocyanurate modified products, uretonimine modified products, uretdione modified products and carbodiimide modified products can also be used. Further, so-called polymeric compounds such as polyphenylene polymethylene polyisocyanate and crude toluene diisocyanate can also be used. These organic polyisocyanates can be used alone or as a mixture of two or more kinds. Moreover, these organic polyisocyanates may be mixed with HDI and then subjected to an allophanate-forming reaction, or may be mixed with an allophanate-modified product of HDI.

Examples of the allophanatization catalyst (c) used in the present invention include metal salts of organic carboxylic acids. 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-
Saturated aliphatic carboxylic acids such as ethylhexanoic acid, saturated cycloaliphatic carboxylic acids such as cyclohexanecarboxylic acid and cyclopentanecarboxylic acid, bicyclo (4.4.0) decane-2
-Saturated polycyclic carboxylic acids such as carboxylic acids, mixtures of the above-mentioned carboxylic acids such as naphthenic acid, unsaturated carboxylic acids such as oleic acid, linoleic acid, linolenic acid, soybean oil fatty acid, tall oil fatty acid, diphenylacetic acid, etc. And aromatic carboxylic acids such as araliphatic carboxylic acid, 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, zirconium and the like. Examples of the transition metal include metals of the boron group such as aluminum, and metals of the carbon group such as tin and lead. Among these, metal salts of alkylcarboxylic acids such as zirconium, zinc and lead are preferable, and zirconium salts of alkylcarboxylic acids are particularly preferable.

As the catalyst poison (d) used in the present invention, known acids such as inorganic acids such as phosphoric acid and hydrochloric acid, organic acids having sulfonic acid group, sulfamic acid group and the like, esters thereof, acyl halides and the like can be used. Can be mentioned.

Further, the allophanate-modified organic polyisocyanate thus obtained is reacted with an active hydrogen group-containing compound to form a thiourethane or a urethane, which can be used as the component (A) in the present invention.

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 resulting organic polyisocyanate has a small number of functional groups. Therefore, the cross-linking density in the polyurethane resin at the time of lens molding becomes small, and the physical properties are likely to deteriorate. When the number of functional groups exceeds 2, gelation is likely to occur during the reaction.

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 "2-MPD")
Abbreviated), 3-methylpentanediol (hereinafter referred to as "3-M
PD) and neopentyl glycol (hereinafter "NP")
G "), 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 (hydroxymethyl) benzene, 1,3-bis (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-mercaptopropane, 1,2-bis (1'-mercaptoethylthio) -3-mercaptopropane (hereinafter referred to as "B
Abbreviated as "METMP"), 1,2,3-tris (1'-mercaptomethylthio) propane, 1,2,3-tris (1'-mercaptomethylthio) propane (hereinafter "TM"
ETP "), 1,2,3-tris (3'-mercaptopropylthio) propane, thioglycerol, dithioglycerol, dimercaptopropanol, pentaerythritol tetrakis (mercaptoacetate) (hereinafter abbreviated as" PETMA "), 1 , 3-bis (mercaptomethyl) benzene (hereinafter abbreviated as "m-MXT").

The compound (B) having two or more active hydrogen groups used in the present invention has a number average molecular weight of 62 to 1,00.
0, preferably 62 to 500. The active hydrogen group (B) is preferably selected from a hydroxyl group and a mercapto group in consideration of reactivity and the like. Specifically, it is a single product or a mixture of a polyol, a polythiol, a hydroxythiol, and a thioether polyol which can be introduced into the above-mentioned HDI allophanate-modified product.

The (B) active hydrogen group-containing compound used in the present invention includes 1,2-PD, 1,2-BD, 1,3-BD and 2
-MPD, 3-MPD, NPG, DEPD, BEPD,
TMPD, EHD, tetrakis (mercaptomethyl) methane, diethylene glycol bis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), 1,2 -Bis (1'-mercaptomethylthio) -3-mercaptopropane, BMETMP, 1,2,3-tris (1'-mercaptomethylthio) propane, TMETP, 1,2,
The use of 3-tris (3'-mercaptopropylthio) propane, thioglycerol, dithioglycerol, dimercaptopropanol, PETMA, m-MXT often gives favorable results.

Furthermore, 1,2-PD, 1,2-BD,
1,3-BD, 2-MPD, 3-MPD, NPG, DE
PD, BEPD, TMPD, EHD, BMETMP, T
Use of METP, PETMA, and m-MXT is particularly preferable because a lens having a high refractive index can be obtained.

The molding method of the plastic lens is (A)
An organic polyisocyanate, (B) an active hydrogen group-containing compound, and a urethane-forming catalyst and an additive as required, were mixed, defoamed as required, and a glass or metal mold and a resin gasket were combined. A known cast molding method such as a method of injecting into a mold and curing by heating can be used. In addition, at the time of blending the raw materials, the mold may be treated with a mold release agent or a mold release agent may be mixed in (A) and / or (B) in order to facilitate removal of the molded product.

The mixing ratio of (A) the organic polyisocyanate and (B) the compound containing an active hydrogen group is preferably such that the ratio of isocyanate group / active hydrogen group is in the range of 0.9 to 1.2,
The range of 0.92 to 1.18 is particularly preferable. When the isocyanate group / active hydrogen group ratio is out of the range of 0.9 to 1.2, the polymerization and the introduction amount of the crosslinked structure are insufficient, and the plastic lens having the high physical properties intended by the present invention is obtained. I can't.

The reaction time and reaction temperature are 20 to 150 ° C.
At 0.5 to 72 hours, preferably 30 to 130 ° C. for 1 to
50 hours. The reaction may be a one-step reaction or a multi-step reaction of two or more steps, but a multi-step reaction is preferable in consideration of heat history and the like. If the reaction temperature or the reaction time exceeds the upper limit, problems such as coloring of the lens occur, which is not preferable as a plastic lens.

Examples of the urethane-forming catalyst that can be used in the present invention include known organic metal salts such as dibutyltin dilaurate, dimethyltin dichloride, bismuth stearate and bismuth oleate, and tertiary amines such as triethylamine and triethylenediamine. There are things.

Examples of additives that can be used in the present invention include ultraviolet absorbers, antioxidants, anti-coloring agents, fluorescent dyes, dispersible dyes, lubricants and surfactants.

[0029]

EXAMPLES 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 the examples and comparative examples, "%"
All mean "mass%".

The refractive index of the resins obtained in the examples and comparative examples,
The heat resistance, moisture resistance, and impact resistance were based on the following test methods. Refractive index: Measured at 20 ° C. using a Pulfrich refractometer. Moisture resistance: 85 ° C for molded products with a diameter of 70 mm and a thickness of 2 mm
The amount of water absorption was measured after 1 hour, 100 hours and 150 hours of immersion in warm water. Impact resistance: Dupont impact tester (manufactured by Yasuda Seiki Co., Ltd.) with a sample size of 3.5 × 3.5 cm,
Height (cm) at which 50% is destroyed using a 300g weight
Was represented. Heat resistance: The obtained lens was heated in an atmosphere of 90 ° C. for 1 week, and impact resistance was measured by the same method as above. In addition, in order to confirm the productivity of plastic lenses when obtaining resins in Examples and Comparative Examples, the time required from the start of mixing at room temperature until the mixed solution is completely defoamed (hereinafter, "defoaming"). (Abbreviated as "time") was measured.

(Synthesis of Allophanate Modified Product of HDI) Synthesis Example 1 A reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with 950 g of HDI and 50 g of isopropanol, and 2-ethylhexane. Add 0.006g of zirconium acid and add 3 at 110 ° C under nitrogen atmosphere.
After reacting for a time, 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 is at 150 ° C and 0.7 kP
Perform thin film distillation at a to remove unreacted HDI and remove H
A DI allophanate modified product was obtained. This is called isocyanate A. The viscosity of Isocyanate A at 25 ° C. is 100 mPa · s, and the isocyanate content is 19.3.
%Met.

Synthetic Example 2 In a device similar to Synthetic Example 1, 900 g of HDI and 100 g of tridecanol were charged, 0.006 g of zirconium 2-ethylhexanoate was added, and the mixture was mixed with 1 in a nitrogen atmosphere.
After reacting at 10 ° C for 3 hours, the isocyanate content is 41
At the time when the content reached%, 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 is heated to 150 ° C.
-Thin film distillation was performed at 0.7 kPa to remove unreacted HDI to obtain a modified HDI allophanate. This is called isocyanate B. Isocyanate B 25 ° C
The viscosity was 180 mPa · s and the isocyanate content was 14.6%.

Comparative Synthesis Example In 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 mixture was reacted at 55 ° C. for 2 hours in a nitrogen atmosphere. Then, 0.10 g of potassium 2-ethylhexanoate was added, and the mixture was reacted at 55 ° C. for 2 hours under a nitrogen atmosphere to give an isocyanate content of 4
At the time of reaching 2%, 0.06 g of phosphoric acid as a catalyst poison
Add and stir for an additional 2 hours. The resulting reaction solution was added to 15
Unreacted HD after thin film distillation at 0 ° C and 0.7 kPa
I was removed to obtain an isocyanurate modified product of HDI. This is designated as isocyanate C. Isocyanate C
Had a viscosity of 2,500 mPa · s at 25 ° C. and an isocyanate content of 21.2%.

Example 1 100 g of isocyanate A, 20.5 g of TMP,
Glass mold and Teflon (registered trademark) treated with a silicone-based baking type release agent after mixing at room temperature to make them uniform
It was poured into a mold consisting of a gasket made of. 4 after injection
3 hours at 0 ° C, 2 hours at 60 ° C, 2 hours at 80 ° C, 10
It was heated at 0 ° C. for 2 hours to be cured. Table 1 shows the defoaming time, the refractive index, the moisture resistance, the impact resistance, and the heat resistance of the obtained lens.

Examples 2 to 6 and Comparative Examples 1 to 6 Using the raw materials shown in Table 1, a plastic lens was obtained in the same manner as in Example 1. Table 1 shows the characteristics of the obtained lens, and Table 2 shows the comparative example.

[0036]

[Table 1]

[0037]

[Table 2]

The abbreviations used in Tables 1 and 2 have the following meanings. HDI: hexamethylene diisocyanate TMP: trimethylolpropane PETMA: pentaerythritol tetrakis (mercaptoacetate) m-MXT: 1,3-bis (mercaptomethyl) benzene DBTDL: dibutyltin dilaurate

[0039]

The plastic lens obtained by the present invention has excellent refractive index, heat resistance, moisture resistance and impact resistance, and is suitable for spectacle lenses, camera lenses and other optical elements. In addition, since defoaming is easy, the productivity of plastic lenses suitable for optical elements is significantly improved.

Claims (3)

[Claims] 1. A plastic lens obtained from a composition comprising (A) an organic polyisocyanate, and (B) a compound having two or more active hydrogen groups,
The organic polyisocyanate (A) contains an allophanate-modified hexamethylene diisocyanate, and
A plastic lens, wherein the modified product has a viscosity at 25 ° C. of 500 mPa · s or less. 2. The plastic lens according to claim 1, wherein the active hydrogen group in the compound (B) having two or more active hydrogen groups is selected from a hydroxyl group and a mercapto group. 3. A method for producing a plastic lens, which comprises injecting the composition according to claim 1 or 2 into a mold and heating the composition to cure the composition.