JP2023048059A - Method for manufacturing organic glass product - Google Patents

Abstract

To provide a method for manufacturing an organic glass product that can make it much quicker to cure a hard coat when manufacturing an organic glass product having a hard coat layer of a thermosetting type on an organic glass.SOLUTION: The present invention relates to a method for manufacturing an organic glass product having a hard coat layer of a thermosetting type on an organic glass. A hard core composition includes (A) alkoxysilane or its hydrolysate to be a mother material monomer, (B) an acetylacetone metal complex as a curing catalysis, and (C) a ceramic colloid sol. Superheated steam (atmosphere pressure) is used as means for heating for curing. The temperature of the superheated steam is set to be not higher than the temperature which thermally affects the base material of the organic glass such as deformation in the curing time (the heating exposure time).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing an organic glass product through a hard coat forming step in which a coating composition is applied onto an organic glass substrate and then cured by heating. Here, optical element substrates are taken as an example of organic glass substrates for explanation, but the same applies to display screens of various mobile devices, window glasses of vehicles and buildings, and three-dimensional organic glass products .

In the present application, “superheated steam” refers to steam heated to a temperature exceeding the atmospheric boiling point (100° C.), and has a large latent heat. In addition, the unit of the number of parts means "mass unit" unless otherwise specified.

In recent years, various glass products have been replacing inorganic glass with organic glass. This is because organic glass is superior to inorganic glass in lightness, impact resistance, workability, dyeability, and the like. However, organic glass is inferior to inorganic glass in scratch resistance.

In order to improve this scratch resistance, the surface of the organic glass base material of optical elements such as spectacle lenses is often coated with a heat-curable silicone-based hard coat (hereinafter simply referred to as "hard coat") (Patent Document 1 [Abstract], [Claim 1], [Claim 2], etc., Patent Document 2 [Claim 2], [0008], etc.). Such a heat-curable hard coat not only has excellent properties such as scratch resistance, adhesion and weather resistance, but also enables reprocessing of the hard coat by immersion in an alkaline aqueous solution. feature. For this reason, the heat-curable hard coat is often used in organic glass substrates such as lenses.

Techniques for ultraviolet curing (Patent Document 3 [0032], etc.) or electron beam polymerization (Patent Document 4 [Claim 1], etc.) using a silane compound introduced with an acrylic group as a matrix are known. However, since these patent documents do not relate to heat-curable hard coats, they do not affect the patentability (inventive step) of the present invention.

Japanese Patent Application Laid-Open No. 5-1258 Japanese Patent Application Laid-Open No. 9-5679 JP-A-10-282302 JP-A-2004-149737

The heat-curable hard coat requires long-time heating to complete curing (obtain practical scratch resistance) of the composition. Practical scratch resistance has been stringent for organic glasses, especially for spectacle lenses. This long heat treatment may cause thermal deformation of the base material, adhesion of foreign matter, and product defects due to non-uniform coating (Patent Document 4 [0004]). Incidentally, if the curing temperature of the hard coat is raised, the curing time will be shortened. For example, Tomoi, "Fundamentals of Thermosetting Resins", Electronics Mounting Society Journal, Vol. 4 No. 6 (2001), p. 539, "The heat release rate strongly depends on the curing temperature. If the curing temperature is raised by 10°C, the curing rate will be approximately doubled, and the curing time will be approximately halved. It will be shortened." However, as shown in Comparative Test Examples, it has been confirmed that hot air heating cannot be expected to significantly shorten the curing completion time (Comparative Example 3 compared to Example 3).

In other words, heating over 100° C. for hard coating hardening of organic glass has been hesitant. This is supported by the descriptions in the following patent documents.
[0052] of Patent Document 1 states that "80 to 100° C. is particularly desirable, and good results can be obtained by heating 2 to 3 times or more." The conditions for the heat treatment in Examples 1 to 3, which are aspects, are also "100° C.×2 hours." Furthermore, the heat treatment conditions in Example 1 of the preferred combination of the epoxy group-introduced silane compound and the acetylacetone metal complex similar to the present invention in Patent Document 2 are also "100° C.×2 h" ([0029]).

In view of the above, the present invention provides an organic glass product having one or more functional layers, including a heat-curable hard coat layer, on an organic glass base material, which can significantly shorten the curing time. It is an object (object) to provide a manufacturing method of.

In order to solve the above problems, the present inventor focused on superheated steam, which is a heating medium exceeding 100 ° C., which has been hesitant in the past, and as a result of intensive research efforts, a hard coat composition (paint) was developed. As a specific example, by performing heat curing with superheated steam (atmospheric pressure), the hard coat curing time (heat exposure time) can be shortened beyond expectations, resulting in long heating (thermal effects) on organic glass. The inventors have found that the occurrence of defective products associated with this can be reduced, and have conceived of the present invention according to the following configurations.

A method for producing an organic glass product having one or more functional layers including a heat-curable hard coat layer on an organic glass substrate, comprising: a hard coat composition comprising (A) a silane compound as a base material; (B) an acetylacetone metal complex as a curing catalyst, and (C) a ceramic colloid sol, together with any one or more of monomers and their hydrolysates and condensates, and heat curing is performed with superheated steam. Characterized by

With the above configuration, the curing time can be shortened beyond expectations by performing heat curing with superheated steam, as shown in test examples described later. In particular, the inclusion of colloidal sol makes it easier to obtain scratch resistance.

In the above invention, the silane compound monomer of (A) consists of or consists mainly of a functional group-containing organic group-introduced silane compound into which a functional group such as an amino group, an epoxy group, a vinyl group, a methacrylic group, a mercapto group, or a halogenated alkyl group is introduced. It is preferable to By having these highly reactive functional groups in the silane compound, the curing time can be shortened, and the effects of adding colloidal sol to the hard coat (scratch resistance, refractive index adjustment, adhesion to anti-reflection coatings, etc.) are ensured. becomes easier. This is because the functional group-introduced silane compound also exhibits a silane coupling action.

In each of the above inventions, it is preferable to preheat the hard coat prior to heat curing to volatilize the residual organic solvent of the coating composition. It is possible to suppress the occurrence of surface defects due to non-uniform curing and bumping caused by residual organic solvent.

In each of the above inventions, the organic glass substrate is molded with a single layer or multiple layers of any of allyl diglycol carbonate resin, polycarbonate resin, thiourethane resin, thioepoxy resin, (meth)acrylate resin and alicyclic polyolefin resin. It is preferable to use a lens substrate with a These resins are preferable from the viewpoint that a thermosetting hard coat can be easily applied.

In the above invention, a function further comprising any one or more of an adhesion function, an impact resistance function, a coloring function, an ultraviolet absorption function, a photochromic function, and a specific wavelength cut function between the organic glass substrate and the hard coat layer. It is preferable to form a flexible coating layer. Drying and curing of these layers can be performed at the same time as curing of the hard coat, and improvement in quality or addition of functionality to organic glass products can be expected.

In the above invention, it is desirable to further form a single-layer or multiple-layer antireflection film on the hard coat layer. It is possible to increase the product value of organic glass products, especially eyeglass lenses.

In each of the above configurations, a configuration in which the hard coat composition does not contain (C) the colloidal sol also belongs to the technical scope of the present invention.

Hereinafter, each of the above configurations (invention specifying matters) of the present invention will be described in detail.
The hard coat composition contains (A) a silane compound, (B) an acetylacetone metal complex, and (C) a ceramic colloid sol, as described above.

(A) In the present invention, the silane compound is not particularly limited as long as it is used for a heart coat. It includes more than one species.
General formula R ¹ _a R ² _b Si(OR ³ ) _4-(a+b)
(Here, R ¹ is a functional group-containing organic group, R ² is an alkyl group having 1 to 3 carbon atoms or a phenyl group, and R ³ is an alkyl group having 1 to 4 carbon atoms or an acyl group. a=0 or 1, b=0, 1 or 2, a+b≦2).
Among these, glycidoxyalkyl groups having 1 to 4 alkyl groups, aminoalkyl groups, methacryloxyalkyl groups, halogenated alkyl groups, and the like can be preferably used as functional group-containing organic groups.

Specifically, known silane compounds exemplified in Patent Documents 1 [0015], [0017] and Patent Document 2 [0014], and further known silane couplings exemplified in Patent Documents 4 [0036] to [0040] agents (functional group-containing organic group alkoxysilanes) can be mentioned.

In addition, in order to adjust the crosslink density and the adhesion to the substrate, tetraalkoxysilane, alkyl-phenyltrimethoxysilane, etc., selected from the above general formulas, can be appropriately used together with the functional group-containing organic group-introduced silane compound. . Here, glycidoxypropyltrimethoxysilane is most preferable as the functional group-containing organic group-introduced silane, tetraethoxysilane as the latter tetraalkoxysilane, and methyltrimethoxysilane as the alkyltrimethoxysilane, respectively.

These silane compounds are preferably hydrolyzed or partially hydrolyzed before use. Furthermore, it is also possible to use the hydrolyzed silane compound after aging it at a low temperature and partially condensing it.
The hydrolysis is carried out by a conventional method of mixing and stirring the silane compound and water in the presence of an acid or base catalyst.

(B) The curing accelerator is appropriately selected from acetylacetonato (acac) complexes of metal ions represented by the following general formula in the present embodiment.
General formula: M _{( CH2COCH3} )n
provided that M is any one of Zr(IV), Fe(III), Sn(II), Al(III), In(III), Zn(II), Co(III), and Cr(III); , n is a number corresponding to the ionic valence of M: 2 or 3.

Among these, (acac) ₃ Al(III), (acac) ₃ Fe(III), and (acac) ₂ Sn(II) are preferable from the viewpoint of curing speed in low temperature curing at 150° C. or less, and particularly , (acac) ₃ Al(III) is preferred.

The blending ratio (converted value after hydrolysis) of these acetylacetonato complexes (C) to the silane compound (A) varies depending on the combination of the two, but (C)/(A)=0.001 to 0. .1, preferably 0.003 to 0.08, more preferably 0.005 to 0.06. If the ratio is too small, it will be difficult to obtain the effect of accelerating the curing.

(C) The ceramic colloidal sol is added from the standpoint of improving scratch resistance and adjusting the refractive index. Specifically, those exemplified in Patent Document 2 [0016] and Patent Document 4 [0010] can be used. From the viewpoint of adhesion to the substrate, it is preferable to contain "silicon dioxide" (Patent Document 4 [0043]). [Claim 3] and [0044] contain a metal oxide having a refractive index of 1.60 or more and a composite oxide thereof. The particle diameter (dynamic light scattering method) varies depending on the layer thickness of the hard coat layer and the refractive index of the organic glass substrate, but for example, 1 to 100 nm, preferably 2 to 50 nm, more preferably 3 to 30 nm. A suitable particle size is used from the range. These colloidal sols are prepared by dispersing them in water or an organic solvent by a conventional method. The solid content concentration varies depending on the particle size and the combination of the dispersion medium and the ceramic fine powder, but it is prepared in the range of 10 to 50%. In this case, the surface of the metal oxide fine particles may be modified with a silane compound, or the fine particles dispersed using a dispersant such as a phosphorus compound may be used.

The mixing ratio of the colloidal sol (B) (converted to solid content) to the silane compound (A) (calculated after hydrolysis) varies depending on the combination of the two, but for example, (B)/(A)=0.1 to 1.5, preferably 0.15 to 1.30, and more preferably 0.2 to 1.2. If the ratio of (B) is small, it is difficult to improve the hardness and to ensure adhesion with the optical thin film (antireflection film, mirror film, optical filter, etc.) formed on the upper layer. Conversely, if the ratio is large, the organic glass It tends to be difficult to ensure adhesion to the base material and difficult to ensure surface smoothness (leveling property).

The hard coat composition of the present embodiment is obtained by appropriately hydrolyzing or partially condensing a general-purpose silane compound (A), and adding a curing catalyst such as an acetylacetone metal complex (B), a ceramic colloid sol (C), or a Add and mix. In this preparation, an organic solvent and a surfactant are appropriately added to the paint from the viewpoint of uniform coating and coating film leveling properties.

The hard coat composition (coating liquid) thus prepared is applied to the organic glass substrate. As this coating method, a dip coating method, a spin coating method, a spray coating method, or the like is appropriately selected, depending on the shape of the base material.

Here, examples of the organic glass used as the molding material for the substrate include general-purpose organic glass such as Patent Document 1 [0053], Patent Document 3 [0011], transparent nylon, alicyclic polyolefin resin, and the like. can be done. For spectacle lenses, general-purpose polymethacrylate and transparent polyamide may be used, but allyl diglycol carbonate resin ("CR39" registered trademark) and polycarbonate resin are used from the viewpoint of strength and water absorption, and thiourethane resin is used from the viewpoint of high refractive index. Resin ("MR-8" registered trademark), episulfide resin (thioepoxy resin) ("MR-174" registered trademark) are preferred.

The uncured coating film formed by coating the hard coating composition on the organic glass substrate in this manner is preheated with hot air or far infrared rays and dried to the touch before being cured by heating with superheated steam. is preferred. The preheating conditions at this time vary depending on the composition of the coating composition (solid content concentration, diluent solvent, etc.), but are, for example, 40 to 100° C., preferably 60 to 95° C., and 3 to 30 minutes. If the preheating temperature is too low or the preheating time is too short, there is a risk that curing failure will occur due to residual solvent during heat curing with superheated steam. If the preheating temperature is too high, the solvent will evaporate rapidly, possibly spoiling the appearance of the hard coat layer. If the preheating time is long, not only is it contrary to the object of the present invention, but it is also undesirable from the viewpoint of energy saving.

The present invention uses superheated steam for heat curing of the hard coat layer. During heating, a very large latent heat is given to the object to be heated. By this method, it is possible to obtain a transparent organic glass substrate having excellent adhesiveness and scratch resistance in spite of the extremely short processing time. The curing conditions with superheated steam vary depending on the combination of (A), (B), and (C) above, but for example, treatment with superheated steam at 105 to 150 ° C. for 10 to 60 minutes is preferable, and productivity ( From the viewpoint of shortening the treatment time) and the thermal effect on the organic glass substrate, treatment with superheated steam at 110 to 140° C. for 15 to 40 minutes is more preferable. If the curing temperature is less than 105° C., the coating layer will be poorly cured, making it difficult to obtain the required scratch resistance. If the temperature exceeds 150° C., the organic glass substrate may be deformed due to heat, and cracks may occur in the hard coat. If the curing time is too short, poor curing may occur, and if the curing time is too long, the hard coat may be damaged due to thermal effects, and excessive heating may occur, which is undesirable from the viewpoint of energy saving.

In the curing with superheated steam according to the present invention, condensed water may be adsorbed on the hard coat layer depending on the conditions. In that case, there is no problem if the condensed water is removed by a conventional drying treatment (heat drying or vacuum drying).

Curing of the coating layer with superheated steam according to the present invention combines latent heat from condensed water, convective heating from superheated steam, and radiant heat, thereby increasing the heating efficiency and exposing the coating layer to superheated steam in a flexible state. Therefore, it is considered that the hard coat is sufficiently cured by hydrolysis and further dehydration condensation of unreacted alkoxy groups.

In addition, in the organic glass substrate according to the present invention, a functional coat can be appropriately interposed between the plastic substrate and the hard coat layer for the purpose of imparting functionality. Here, the functionality is not particularly limited and includes adhesion function, impact resistance function, coloring function, ultraviolet absorption function, photochromic function, specific wavelength cutting function containing a specific wavelength cutting agent, and the like.

Further, in the organic glass substrate according to the present invention, a single-layer or multi-layer general-purpose antireflection film can be formed on the hard coat layer by a conventional vacuum deposition method, sputtering, or ion plating.

Hereinafter, the present invention will be described more specifically based on examples together with comparative examples. However, the technical scope of the present invention is not limited to the aspects described in these examples, and extends to various aspects within the scope described in each claim.

(I) The organic glass substrates used in Examples and Comparative Examples were cast-molded from the following commercially available products.
・“CR-39” (registered trademark): diallyl glycol acrylate resin manufactured by PPG ・“MR-8” (registered trademark): thiourethane resin A (nd: 1.59) manufactured by Mitsui Chemicals, Inc.
・"MR-7" (registered trademark) ... the same thiourethane resin B (nd: 1.67),
・"MR-174" (registered trademark) ... the same thioepoxy resin (nd: 1.74),

(II) Preparation of hard coating solution According to the formulation shown in Table 1, the solution was prepared by the following procedure. In Table 1 and the following description, "Example" and "Comparative Example" are abbreviated as "actual" and "comparative", respectively, followed by corresponding numbers. Each silane compound was diluted with methanol to an appropriate viscosity, and hydrolyzed with stirring at room temperature for about one day using an acid catalyst. Next, after diluting this hydrolyzate with methanol to an appropriate viscosity, the indicated colloidal sol and curing accelerator were blended together with an appropriate amount of leveling agent (nonionic surfactant), and stirred at room temperature for about one day. A hard coat liquid was prepared.

As the ceramic colloidal sol, commercial products having the following specifications were used.
・ "Silica sol" ... average particle size (dynamic light scattering method): 22 nm, solid content concentration: 35%, aqueous dispersion system,
"Zirconia sol" ... average particle size (dynamic light scattering method): 3 nm, solid content concentration: 30%, methanol dispersion system,

(III) Formation of hard coat layer Each organic glass substrate is immersed in each hard coat liquid, pulled up at a speed of 150 mm/min (dip coating method), preheated at 90°C for 10 minutes, and then Each coat layer was formed by heating and curing under each condition shown.

(IV) Preparation of Functional Coating Solution To 60 g of commercially available water-dispersed self-emulsifying polyurethane emulsion (solid content 30%, pH 8), 2 g of carbodiimide as a cross-linking agent is added to 400 g of methanol, and an appropriate amount of leveling agent (nonionic interface activator), and stirred at room temperature for about a day and night to prepare.

(V) Formation of functional coating layer After being immersed in the above functional coating solution, it was pulled up at a speed of 150 mm/min (dip coating method) and heat-treated at 100°C for 15 minutes (pre-drying treatment) to improve adhesion. A coat layer was formed for the purpose of imparting After that, the hard coat layer was formed.

(VI) Formation of Antireflection Film In Example/Comparative Example 6, SiO ₂ /ZrO ₂ : 1/4λ, ZrO ₂ : were deposited on the hard coat layer formed on the organic glass substrate by vacuum deposition. An antireflection film having a structure of 1/2λ and SiO ₂ : 1/4λ was formed.

[Evaluation Test of Transparent Organic Glass Substrate]
The specimens of Examples and Comparative Examples prepared above were subjected to the following evaluation tests.

[Evaluation method]
(1) Appearance The transparent organic glass substrates of the above examples and comparative examples were visually checked for abnormalities (cracks, cloudiness, etc.) in the coating layer directly under a three-wavelength fluorescent lamp.

(2) Scratch resistance test The surfaces of the transparent organic glass substrates of the above examples and comparative examples were subjected to a load of 700 g on Bonstar Steel Wool #0000 (manufactured by Nippon Steel Wool Co., Ltd.), and the test was performed 30 reciprocations/30 seconds. (stroke length), and the degree of scratching was visually evaluated according to the following criteria.
5: Almost no scratches 4: Slight scratches 3: Considerable scratches 2: Scratches on almost the entire rubbed area 1: Deep scratches on almost the entire rubbed area

(3) Normal state adhesion test A cutter knife was used to cut the surface of each test piece at intervals of 1 mm to form 100 squares of 1 mm square, and after strongly pressing a cellophane adhesive tape (manufactured by Nichiban), 90 It was rapidly peeled off in the direction of degrees (10 times), and the number of squares not peeled off at all was counted and judged according to the following criteria.
5: The number of remaining squares is 100 (no peeling)
4: The number of remaining squares is 90 or more and less than 100 3: The number of remaining squares is 70 or more and less than 90 2: The number of remaining squares is 50 or more and less than 70 Less than 1: Less than 50 remaining squares

(4) Adhesion Test after Immersion in Boiling Salt Water After the boiling test in which each specimen was immersed in boiling 10% salt water for 60 minutes, the adhesion test was performed. In addition, the antireflection coating was not carried out in Example 6, in which the antireflection coating was formed, because the antireflection coating would be damaged.

(5) Adhesion Test after Immersion in Hot Water Each specimen was immersed in hot water (80° C.) for 30 minutes and then subjected to the adhesion test described above. Actual ratio 6 on which an antireflection film was formed was performed instead of the adhesion test after immersion in boiling salt water.

From Table 2 showing the results of each evaluation test, the following has been confirmed. There were no problems with any of the specimens in terms of the appearance and condition of the specimens, and the adhesion of the specimens immersed in boiling salt water.
(i) Example 1 1'... Comparison 1 using coating liquid H4 containing no colloid sol (silica sol) has better scratch resistance (hardness) than Example 1 using coating liquid H1 containing colloid sol. Inferior.
(ii) Example/Comparative Example 2...Comparison 2 using H5, in which the curing accelerator is a carboxylic acid/dicyandiamide combination system, has better scratch resistance ( hardness) is inferior.
(iii) Example/Comparative Example 3: Comparative Example 3, in which the heating means is hot air, is inferior in scratch resistance (hardness) to Example 3, in which the same superheated steam is used, even if the heating temperature and time are the same. .
(iv) Example/Comparative Example 4: In Comparative Example 4, in which hot air was used as the heating means, the heating time was set to about 20 to 120 minutes in order to obtain the same scratch resistance as Example 4, in which the same superheated steam was used. need to be significantly longer.
(v) Example/Comparative Example 5: Even when the organic glass base material is an episulfide resin and a functional coating layer is interposed, as in Example 3, Ratio 5 is lower than Example 5. Inferior scratch resistance.
(vi) Example/Comparative Example 6: Even when an anti-reflection film is formed in Example/Comp.

Claims (7)

A method for producing an organic glass product having a heat-curable hard coat layer on an organic glass substrate, wherein the hard coat composition comprises (A) a silane compound monomer as a base material and a hydrolyzate thereof and condensate, (B) an acetylacetone metal complex as a curing catalyst, and (C) a ceramic colloid sol, and the heat curing is performed with superheated steam. How the product is made. The silane compound of (A) consists of or is mainly composed of a functional group-containing organic group-introduced silane compound having a functional group such as an amino group, an epoxy group, a vinyl group, a methacrylic group, a mercapto group, or a halogenated alkyl group. The method for producing an organic glass product according to claim 1. 3. The method for producing an organic glass product according to claim 1, wherein the hard coat is preheated to volatilize the residual organic solvent of the coating composition prior to the heat curing of the hard coat. A lens substrate obtained by molding the above organic glass substrate into a single layer or multiple layers of any one of allyl diglycol carbonate resin, polycarbonate resin, thiourethane resin, thioepoxy resin, (meth)acrylate resin and alicyclic polyolefin resin. The method for producing an organic glass product according to claim 1, 2 or 3, characterized in that: A functional coat layer further provided between the organic glass substrate and the hard coat layer and having at least one of an adhesion function, an impact resistance function, a coloring function, an ultraviolet absorption function, a photochromic function and a specific wavelength cut function. 5. The method of manufacturing an organic glass product according to claim 4, characterized in that forming a. 6. The method for producing an organic glass product according to claim 1, further comprising forming a single-layer or multi-layer antireflection film on the hard coat layer. A method for producing an organic glass product having one or more functional layers including a heat-curable hard coat layer on an organic glass substrate, wherein the hard coat composition is used as (A) a base material monomer. (B) an acetylacetone metal complex, which is a curing catalyst, in addition to any one or more of silane compounds and/or their hydrolysates and condensates, and superheated steam (large A method for producing an organic glass product, characterized in that atmospheric pressure is used.