JPH0341402A - Transparent antifogging material - Google Patents

Abstract

PURPOSE:To obtain the transparent antifogging material which simultaneously satisfies the improvement in an antifogging property and surface hardness by forming a porous layer of 3000Angstrom to 10mum thickness consisting of silicon oxide on a transparent synthetic resin base material on which a surface layer satisfying specific formula is provided. CONSTITUTION:The transparent synthetic resin base material 1 consists of the base material 10, such as transparent acrylic resin, and the surface layer 11 which is provided on the surface thereof and satisfies the formula I. In the formula, F is the value of the molar number (mumol/cm<2>) at which a basic dye can react or stick per unit area of the base material surface and Hv is the value of the Vickers hardness measured by a method complying with JIS-Z-2244. The thickness of the porous layer 3 consisting of the silicon oxide formed on this base material 1 is specified to 3000 deg. to 10mum thickness. The adhesive property of the porous layer 2 consisting of the silicon oxide is enhanced and the improvement in the antifogging property and the surface hardness is simultaneously attained if the compd. satisfying the formula I is used as the surface layer 11. In addition, the transparent antifogging material with which the high adhesive property is obtainable is obtd. without being affected by the kind of the resin material used as the base material.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to transparent materials such as mirrors, eyeglass lenses, windows, etc. that require antifogging properties, and a humidity sensor that utilizes impedance changes due to moisture absorption. The present invention relates to an anti-fogging material that is transparent and has a high surface hardness, and is suitable for applications such as the following.

(Prior Art) There is a high demand for imparting antifogging properties to transparent synthetic resin materials, especially in the fields mentioned above, and many methods have been developed and attempts have been made to put them into practical use for a long time. Representative examples are as follows.

■ A method of coating a transparent synthetic resin with a hydrophilic organic thin film, ■ A method of adding water-absorbing inorganic particles such as silica gel into a transparent synthetic resin, ■ A method of making the surface of a transparent synthetic resin hydrophilic by a physical method such as plasma discharge treatment. Methods: (1) A chemical method of generating hydrophilic groups on the surface of a transparent synthetic resin by surface hydrolysis, etc. (2) A method of forming a hydrophilic inorganic compound layer on the surface of a transparent synthetic resin (see JP-A-60-210641).

(Problem M that the invention seeks to solve) However, among the above conventional methods, method (2) has a problem with the durability of the anti-fog property, and at the same time, it is not possible to increase the hardness of the surface and improve the scratch resistance. Methods (2) and (2) cannot be expected to have a sufficient antifogging effect, nor can they be expected to improve surface hardness. Furthermore, the physical or chemical methods described in (1) and (2) are also unable to satisfy the requirements of anti-fogging properties and improvement of surface hardness.

Method (2) involves forming a silicon-based compound directly on the surface of a transparent synthetic resin using vacuum evaporation or sputtering.
This method can be expected to improve the surface hardness of the treated surface, but this method has the disadvantage that it is difficult to obtain adhesion to the type of synthetic resin used as the base material, especially the highly transparent acrylic resin.

In view of these circumstances, the present invention has been developed to provide a transparent anti-fog that can simultaneously exhibit anti-fog properties and improved surface hardness, and that also provides high adhesion without being affected by the type of transparent synthetic resin used as the base material. The purpose is to obtain materials.

(Means for Solving the Problems) That is, the present invention has been made to achieve the above-mentioned problems. , thickness 3000
Transparent antifogging material F' X Hv≧0.3 (where P is the unit area of the base material surface where the basic dye is It is the value of the number of moles (μmot/crl?) that can react or adhere per contact, and is the value of Vickers hardness measured by a method based on Hv J Engineering 5-Z-2244).

The present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view showing an example of the transparent antifogging material of the present invention, in which (1) is a transparent synthetic resin base material and (2) is a porous layer made of silicon oxide. In this example, the transparent synthetic resin base material (1) consists of a base material (10) made of transparent acrylic resin, and a surface layer (11) provided on the surface of the base material (10) that satisfies the following formula.

F By using a compound that satisfies this formula, the adhesion of the porous layer (11) made of silicon oxide can be improved. ) acrylate, neopentyl alcohol di(meth)acrylate,
Triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, diethylene glycol di(meth)acrylate, 2-hydroxyethyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, N-vinylpyrrolidone, cyclohexyl(meth)acrylate ) acrylate, dipentaerythritol hexaacrylate, bentaerythritol triacrylate, tripropylene glycol diacrylate, and the like. Although the transparent resin base material may be composed of such a compound alone, it is preferable to form it as a thin layer on the surface of a base material such as acrylic resin as shown in the figure. The thickness of the surface layer (11) at this time is not particularly limited, but it is sufficient if it is 2 μm or more,
When the base material (1o) is an acrylic resin, the thickness is preferably about 2 to 30 μm. The acrylic resin used for the suit base material (10) is one that is widely used as an acrylic resin, such as a polymer of methyl methacrylate alone or a copolymer made of methyl methacrylate as the main component and copolymerized with other vinyl thread monomers. sell.

Next, the porous layer (2) is made of silicon oxide and has a thickness of 3000 Å.
-10 pm, more preferably less than 5,000, the antifogging effect will be insufficient; conversely, if it exceeds 10 pm, cracks will easily occur, causing problems in handling. In order for this silicon oxide to exhibit excellent antifogging properties, it has a favorable structure in which the silicon oxide has an extremely fine particle shape that aggregates to form a porous thin film layer. More preferably, the particle size is 200OA or less.

The above porous layer is formed by using P, V, D,
More preferably, an RF sputtering method targeting Sl is used, and by using oxygen as the active gas, the desired porous silicon oxide film can be obtained.

(Example) Examples of the present invention will be described below, and evaluation of physical properties was measured by the following method.

(The value Q of 111P (the number of moles that a basic dye can react or adhere to per unit area of the substrate surface), the concentration of Eisen methyl violet was set to 1.0 using IN sodium acetate buffer (pH 4, 5). A transparent synthetic resin substrate with a size of 50 x 50 sheets was immersed in this solution for 48 hours, washed with water-99 ethanol solution-water, and wiped with water.
The absorbance of light at 0 nm was measured.

On the other hand, a calibration curve of dye concentration was determined from the above dye solution, and the number of moles of functional groups that could react with or adhere to the basic dye was calculated.

(2) Value of Hv (Vickers hardness), T-work 5-Z-
(3) Total light transmittance Measured in accordance with ASTM D-1003 (4) Adhesion Peeling test of cellophane tape by cross-cutting, that is, cutting into the porous membrane until it reaches the base material. Cellophane tape was adhered to 100 squares, spaced 1 meter apart by 11 people vertically and horizontally, and then rapidly peeled upward to examine the situation. The evaluation is as follows.

・5th grade: No peeling ・4th grade: 1 to 24 pieces peeling ・3rd grade: 25 to 49 pieces peeling ・2nd grade: 50 to 74 pieces peeling ・1st grade: 75 or more pieces peeling (5) Anti-fogging temperature 20℃, humidity 65% In a room, the sample was observed by directly blowing steam in a constant temperature water bath with a water temperature of 60°C, and the sample surface was judged as × if it became cloudy, △ if it was slightly cloudy, and ○ if it was not cloudy at all.

Example 1 Acrylic resin plate “Acrylite Lj” manufactured by Mitsubishi Rayon Co., Ltd.
A liquid having the following composition was spin-coded onto a sample having a thickness of 2III+1 (vertical and horizontal: 50 x 50) and irradiated for 15 minutes using a high-pressure mercury lamp (20 W) at a distance of 15 crn to form a surface layer with a thickness of 2 μm.

- 30 parts by weight of tetrahydrofurfuryl acrylate - 30 parts by weight of a condensate of succinic acid/trimethylolethane/acrylic acid - 40 parts by weight of dipentaerythritol hexaacrylate - 2 parts by weight of Darocure 1173J (photoinitiator manufactured by Merck & Co.) The F X Hv value of the surface layer obtained with the composition is 1
．． 42 (II' = 0.063, HV = 22.5), but when we measured the surface of "Acrylite L" just to be sure, the F
v=22.4).

Next, on this surface layer, the target was set to Si by RF sputtering method, and the Ar partial pressure was changed to 6×10-” TOr.
r, 02 partial pressure to 1.5 X 10-' Torr,
The RF input power was set to 200 W, and silicon oxide films of various thicknesses were formed to produce transparent antifogging plates. The silicon oxide at this time was a fine porous layer with an average particle size of 2000A or less.

These performances are shown in Table 1, and it was confirmed that the product of the present invention was excellent in antifogging properties and surface hardness.

Table 1 For comparison, when silicon oxide was directly formed on the surface of "Acrylite L" by RF sputtering under the same conditions, the layer thickness was 1,000 to 20. OD OA
The adhesion was grade 1 in all cases.

Example 2 0.03 Ni part of benzoyl peroxide was added as a polymerization initiator to a mixture of ethylene glycol dimethacrylate (A) and methyl methacrylate (B), and the mixture was polymerized at 65°C to form a substrate with a thickness of 2 cm. It was created.

Then, a porous layer of silicon oxide was formed on this substrate under the same conditions as in Example 1. The performance of the obtained transparent antifogging material is shown in Table 2, and it was confirmed that the performance was excellent.

Table 1 (Effects of the Invention) Since the present invention has the structure described in detail above, it is possible to obtain a durable and transparent anti-fog that satisfies both anti-fog properties and scratch resistance due to improved surface hardness. It has the advantage that it can be used as a material for various optical materials such as eyeglass lenses and mirrors, and as a humidity sensor material.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view showing one embodiment of the present invention. (1) Transparent synthetic resin base material, (2) porous layer

Claims (1)

[Claims] Transparent antifogging material FXH_v characterized in that a porous layer made of silicon oxide with a thickness of 3000 Å to 10 μm is formed on a transparent synthetic resin base material whose surface portion satisfies the following formula: ≧0.3 (wherein, F is the number of moles (μmol/cm^2) that the basic dye can react or adhere to per unit area of the substrate surface, and H_v is the value based on JIB-Z-2244. Vickers hardness measured by the method).