JPH02147308A - Manufacture of polyurethane lens - Google Patents

Abstract

PURPOSE:To enhance the heat resistance of a polyurethane lens by casting a liquid mixture prepared by adding polyisocyanate to a reaction product obtained by reacting polyol with a specific ratio of polyisocyanate in a lens manufacturing mold to polymerize the same. CONSTITUTION:A reaction product is obtained by reacting polyol with polyisocyanate in a ratio of 0.001 - 0.3 equivalent per one equivalent of polyol. Further, polyisocyanate is added to the reaction product to obtain a liquid mixture. The mixing amount of polyisocyanate is pref. set to such a range that the equivalent ratio of polyisocyanate to polyol is set to 0.5 - 3.0 in the sum amount containing the amount of polyisocyanate to be used. The liquid mixture is cast in a lens manufacturing mold and polymerized to obtain a polyurethane lens. With respect to the polymerization temp. in casting polymerization, initial temp. is pref. 5 - 40 deg.C and may be raised to 100 - 130 deg.C over 10 - 70hr.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a polyurethane lens having excellent heat resistance and used for various optical lenses such as eyeglass lenses and camera lenses.

<Prior Art> In recent years, demand for plastic lenses, for example, as eyeglass lenses, has been increasing both domestically and internationally. Plastic lenses that have been used in recent years are generally made of DAC81 resin, which is obtained by cast-polymerizing diethylene glycol bisallyl kaobonate (hereinafter abbreviated as DAC). DAC resin has the advantages of being lighter than glass, less likely to break, and has excellent dyeability, and can meet the rich fashion needs of combining colored lenses with today's large frames. However, the refractive index (hereinafter abbreviated as NO) of DAC resin is 1.500, which is lower than the No. 1°523 of a glass Ill lens. Therefore, especially when the lens power is strong, users are forced to make the lens thicker. It is not very well liked.

Therefore, the ND is 1°56~ than that of the DAC resin lens.
Polyurethane lenses are known as plastic lenses that have a relatively high refractive index of 1.64. As a method for manufacturing this polyurethane lens, for example, a special fml
In 1160-217229, polyisocyanate and S atom-containing polyol are simultaneously mixed,
A method has been proposed in which polyurethane lenses are obtained by performing cast polymerization with uniform stirring. Also, JP-A-60-19
Publication No. 9016 proposes a method of obtaining a polyurethane lens by simultaneously mixing polyisocyanate and a polythiol in which all of the water m groups of the polyol have been replaced with mercapto groups, stirring uniformly, and carrying out casting overloading. .

<Problems to be Solved by the Invention> However, polyurethane lenses obtained by the methods proposed in JP-A-60-217229 and JP-A-60-199016 are generally made from radical polymerization type resins with olefin groups. For example, because it has inferior heat resistance compared to DAC resin, it tends to deform during post-processing such as lens dyeing or surface coating, which usually requires heat processing at about 60 to 90°C. There are drawbacks that must be kept low.

Therefore, an object of the present invention is to use polyisocyanates and polyols (including those in which one or more of the 011 groups is substituted with an SH group; the same applies hereinafter) in order to increase the degree of freedom in selecting thermal conditions in post-processing such as dyeing and surface coating. ) It is an object of the present invention to provide a manufacturing method for relatively improving the heat resistance of various polyurethane lenses.

Means for Solving the Problems> In view of the above circumstances, the present invention involves casting a monomer mixture containing a polyisocyanate and a polyol in a lens manufacturing mold to inject a polyurethane lens. A method for producing a polyurethane lens is characterized in that it includes the following three steps.

(a) A first step in which the polyol is reacted with a polyisocyanate at a ratio of 0.001 to 0.3 equivalents per 1 equivalent age of the polyol to obtain a reaction product.

(0) A second step of adding polyisocyanate to the reaction product to obtain a mixed solution.

(c) A third step in which the mixed solution is cast-polymerized in a lens manufacturing mold to obtain a polyurethane lens.

The present invention will be explained in detail below.

Polyisocyanates used as monomers for producing polyurethane lenses in the present invention are not particularly limited, but include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, naphthylene diisocyanate, hexamethylene diisocyanate, Hydrogenated diphenylmethane diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanate phenyl)thiophosphate, trans-cyclohexalene 1.4-diisocyanate, P-phenylene diisocyanate, 1.8-
Polyisocyanate compounds such as diisocyanate-4-isocyanate methyl octane, lysine ester triisocyanate, 1.3.6-hexamethylene triisocyanate, bicyclopeptane triisocyanate, isophorone diisocyanate, and allophanate modified products and biuret modified products of these compounds. , an isocyanurate modified product, a polyol or an adduct modified product with a polythiol, etc., and may be used alone or as a mixture of two or more types. Other isocyanate compounds having two or more functional groups can be used, and furthermore, a halogen atom such as C1 or 8r may be introduced into the aromatic isocyanate compound (having two or more functional groups).

Particularly preferred isocyanate compounds include non-yellowing isocyanate compounds represented by xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

In the present invention, the polyol used in the reaction with polyisocyanate for producing polyurethane lenses is also not particularly limited. Examples include ethylene glycol, diethylene glycol, propylene glycol, glycerol butanediol, glycerol, bentanediol, pentanediol, hexanediol, hexanediol, cyclohexanediol, cyclohexanetriol, etc., but some or all of the hydroxyl groups of these polyols In terms of reactivity in cast polymerization and refractive index as a resin for lenses, compounds in which the Particularly preferred are derivatives of pentaJ-lythritol. Of course, these polyols can be used alone or as a mixture of 211 or more.

Next, 0 for the polyol and 1 equivalent of the polyol.
．． The first step of obtaining a reaction product by reacting with polyisocyanate at a ratio of 0.001 to 0.3 equivalent ω will be explained.

If the amount of polyisocyanate exceeds a ratio of 0.3%, the effect of improving heat resistance will be small and optical distortion will easily occur.
On the other hand, if the ratio is less than 0.001'Jffl, the effect of improving heat resistance is almost lost, which is not preferable.

In this reaction, the remaining amount of polyisocyanate used was 1
Of! It is desirable to carry out the process until t11% or less.

If the residual m of the polyisocyanate used exceeds 10% by weight, the effect of improving heat resistance will decrease, which is not preferable.

The conditions for this reaction are not particularly different from ordinary urethane production reactions (the reaction temperature varies depending on the type of monomer used, etc., but - for boat fishing, the temperature is -20°C to 150°C, 0.5°C).
Carry out under stirring for ~72 hours. Reaction temperature is 150℃
Exceeding this is not preferable because the resulting lens is likely to be colored, optical distortion, or non-uniform.

Further, in the first step, known additives can be added as necessary. Examples include light stabilizers, ultraviolet absorbers, antioxidants, polymerization catalysts, antifoaming agents, and the like.

Furthermore, the second step of adding polyisocyanate to the reaction product to obtain a mixed solution will be explained.

The amount of polyisocyanate to be mixed in the second step, including the amount of polyisocyanate used in the first step, is such that the equivalent ratio of polyisocyanate to polyol is 0.5.
A peak within the range of ~3.0 is preferred. If the equivalent ratio of polyisocyanate to polyol used is less than 0.5 or more than 3.0, it is undesirable because it becomes difficult to obtain a lens having good properties not only in terms of heat resistance, which is the objective of the present invention, but also in terms of optical distortion. .

Moreover, additives can be added to the mixed liquid as necessary. Examples include light stabilizers, ultraviolet absorbers, 9M inhibitors, polymerization catalysts, mold release agents, antifoaming agents, and the like.

The polyisocyanate used in the second step may be the same polyisocyanate used in the first step, or a different polyisocyanate.

Furthermore, the third step of obtaining a polyurethane lens by casting the mixed liquid in a lens manufacturing mold will be explained.

As for the polymerization temperature in cast polymerization, the initial temperature is 5 to 4
The temperature range is preferably 0°C, and the temperature is 100 to 1
It is best to raise the temperature to 30°C. If the initial temperature is lower than 5°C, the polymerization time will be unnecessarily long, and the initial temperature will be too long! J temperature is 40
If the temperature is higher than ℃, the resulting lens will become optically inhomogeneous. Furthermore, if the final temperature is less than 100°C, unreacted substances tend to remain and the degree of polymerization will be low, resulting in a decrease in physical properties such as refractive index and surface hardness, and if the final temperature exceeds 130°C, the resulting lens will turn yellow. do.

Examples of lens manufacturing molds include combinations of glass molds, metal molds, ceramic molds, and Teflon gaskets.

The obtained polyurethane lenses can be dyed, polished, and coated with abrasion-resistant silicon-containing or acrylic thin films or anti-reflection films made of inorganic or organic substances, as well as anti-fog and water- and oil-repellent treatments. may be applied.

<Examples> Hereinafter, the present invention will be specifically explained using examples. The refractive index, Abbe's number, impact resistance, optical distortion, and heat resistance of the lens resins obtained in the examples were determined by the following methods.

Refractive index, Atsube number: Measured using a tJ Atsube refractometer manufactured by Elma Optical Co., Ltd.

Impact resistance: Those that satisfied the US FDA safety standards for eyeglass lenses were rated as good, and those that did not were rated as poor.

Optical distortion: Evaluated using a strain meter.

Heat resistance: Thickness 3 using Rigaku Denki Co., Ltd. TMA8140
．． Indentation method (bottle diameter Q
, 5 mm, load 10 g), the temperature was raised at 10° C. per minute, and the thermal deformation onset temperature was measured.

Example 1 [First step] m-xylene diisocyanate (m-XDI) 11.8
Dibutyl dene dilaurate (D
BTL) 0.1 part by weight of pentaerythritol tetrakis 3-mercaptopropionate (
PETMP) 122.0 parts by weight (the equivalent ratio of polyol and polyisocyanate is 0.126) was added and dissolved uniformly, and then heated at 80°C for 24 hours to obtain m-x
oI and PETMP were reacted to obtain a reaction product.
When the infrared absorption spectrum of the obtained reaction product was measured, no absorption based on the isocyanate group of m-XD I was detected.

[Second step] The reaction product obtained in the first step was cooled to 20°C, and m
-XD I was added in 91.6 weight parts and stirred sufficiently until it became homogeneous. ) was obtained.

[Third step] After stopping the stirring of the mixed liquid obtained in the second step and forming sharp bubbles in a stationary state, a lens manufacturing mold consisting of a glass mold treated with a silicone mold release agent and a Teflon gasket is formed. The mixed solution was poured into the reactor, and the initial temperature was maintained at 1125°C for 5 hours, and then the temperature was raised and maintained at 40°C for 5 hours, 60°C for 7 hours, 80°C for 3 hours, and 120°C for 2 hours to polymerize. A polyurethane lens was obtained. Obtained polyurethane lens N
O was 1.592, ν0 was 36, the thermal deformation onset temperature indicating heat resistance was 95.5°C, there was no optical distortion, and the impact resistance was also good.

Example 2-6 Lenses were produced with each composition in Table 1 under the same manufacturing conditions as in Example 1, and the results are shown in Table 1.

Comparative Example 1 The physical properties of a polyurethane lens obtained by mixing polyol and polyisocyanate at once without reacting the polyol and polyisocyanate beforehand, stirring uniformly, and performing cast polymerization were investigated. The m-XDIffl and PETMPffi used in Comparative Example 1 were the same as those used up to the second step of Example 2, and the physical properties were compared with the polyurethane lens obtained in Example 2.

First, m-XDI 103.4 fold ω part: DBTLO
, imtim, FC solution, PET
M1) Add 122.0 parts by weight (equivalent ratio with polyol or polyinsyanate is 1.10, which is the same as the equivalent ratio in the second step of Example 2), dissolve uniformly, and carry out the following steps. A polyurethane lens was obtained under the same conditions as in the third step of Example 1. The obtained lens had a ν0 of 36, no optical distortion, and good impact resistance, but the thermal deformation starting temperature was 85.8°C, which was inferior to the thermal deformation starting temperature of 92.4°C in Example 2. Ta.

Comparative Example 2 Similarly to Comparative Example 1, polyurethane lenses were obtained by mixing polyol and polyisocyanate at once without reacting them in advance, stirring uniformly, and performing cast polymerization. Various physical properties were investigated.
The m-XDIffi, tolylene diisocyanate (TDI) amount, and PETMPffi used in Comparative Example 2 were the same as those used up to the second step of Example 4, and
The physical properties were compared with that of the polyurethane lens obtained in .

First, m-XDI 87.0 superposition part, TOllo,
9 parts by weight (the equivalent ratio of polyol and polyisocyanate is 1.05, which is the same as the equivalent ratio in the second step of Example 4).
becomes. ), 0.1 parts by weight of DBTL were added and uniformly dissolved, and thereafter a polyurethane lens was obtained under the same conditions as in the third step of Example 1.

The obtained lens had NO of 1,600, ν0 of 33, no optical distortion, and good I impact resistance, but the thermal deformation onset temperature was 90.2°C, which was 99°C, which was the thermal deformation onset temperature in Example 4. ．．
It was inferior to 4°C.

Comparative Example 3 A polyurethane lens was prepared under the conditions that the equivalence ratio of polyol and polyisocyanate exceeds 0.3 in the first step of the present invention, and various physical properties were investigated.

[First step] m=XDI 32.9 In the overlapping part, P E 1' M
After adding and uniformly dissolving 22.0 ml of Pl (the equivalent ratio of polyol and polyisocyanate is 0.350), it was heated at 80°C for 24 hours to dissolve m-XDI and Pl.
When reacted with ETMP and measured the reaction product using an infrared absorption spectrum, no absorption based on the isocyanate group of m-XDI was detected.

[Second step] The reaction product obtained in the first step was cooled to 20°C, and m
-XDI was added in an amount of 70.5 parts by weight, and the mixture was thoroughly stirred until the mixture became homogeneous to obtain a mixed solution of the reaction product and m-XDI (the equivalent ratio of polyol to polyisocyanate was 1.10). .

(Step 31 1 A polyurethane lens was obtained using the mixed liquid obtained in the second step under the same conditions as in the third step of Example 1.

The obtained lens had an ND of 1.592, a νO of 36, a thermal deformation onset temperature of 90.3°C, and good II impact resistance, but it was so poor that it could not be used for eyeglass lenses, camera lenses, etc. Bad optical distortion was observed.

Comparative Example 4 A polyurethane lens was prepared under the conditions that the equivalent ratio of polyol to polyisocyanate in the first step of the present invention was less than 0.001, and various physical properties were investigated.

[First step] Add DBTL O to m-XDI 0.2ffiffi part
, IEl fR addition site t-%, PETMP 366
, O@ffi part (the equivalent ratio of polyol and polyisocyanate is 0.0007) was added and uniformly dissolved, and then heated at 80° C. for 24 hours to obtain a reaction product.

When the infrared absorption spectrum of the obtained reaction product was measured, no absorption based on the isocyanate group of m-Xr)I was detected.

[Second step] The reaction product obtained in the first step was cooled to 20°C, and m
Add 310.0 Iflf5 parts of -XDI and stir thoroughly until the mixture becomes homogeneous.A mixture of the reaction product and m-XDI (equivalency ratio of polyol and polyisocyanate is 1.
It becomes 10. ) was obtained.

[Third Step] A polyurethane lens was obtained using the mixed liquid obtained in the second step under the same conditions as in the third step of Example 1. The NO of the obtained lens was 1,592. νD was 36, which was good with no optical distortion observed, but the thermal deformation onset temperature was 86.0° C., which was a lens with heat resistance comparable to that of the lens obtained in Comparative Example 1.

(Left below) (Note) The compounds indicated by abbreviations in Table 1 are as follows.

m-XDI m-xylene diisocyanate PETM
P Pentaerythritol Detrakismerkabutoprobionate TDI t-lylene diisocyanate The polyurethane lens manufacturing method, which includes the three steps described above, allows various polyurethane lenses to be relatively improved in heat resistance, dyed, surface coated, etc. It has become possible to increase the degree of freedom in selecting thermal conditions in post-processing.

<Effects of the Invention> A method for manufacturing a polyurethane lens by cast-polymerizing a monomer mixture containing a polyisocyanate and a polyol in a lens manufacturing mold, comprising: (a) the polyol, the polyol 1 and the polyol; The first step is to react with polyisocyanate at a ratio of o, ooi to 0.3 to obtain a reaction product.

(b) A second step of adding polyisocyanate to the reaction product to obtain a mixed solution.

(c) A third step in which the mixed solution is cast-polymerized in a lens manufacturing mold to obtain a polyurethane lens.

Claims (1)

[Claims] (1) Polyurethane lenses are produced by cast-polymerizing a monomer mixture containing polyisocyanate and polyol (including those in which one or more OH groups are replaced with SH groups) in a lens production mold. A method for producing a polyurethane lens, the method comprising the following three steps. (a) A first step in which the polyol is reacted with a polyisocyanate in a proportion of 0.001 to 0.3 equivalents per equivalent of the polyol to obtain a reaction product. (b) A second step of adding polyisocyanate to the reaction product to obtain a mixed solution. (c) A third step in which the mixed solution is cast-polymerized in a lens manufacturing mold to obtain a polyurethane lens.