JPH0285353A - Method for coating plastic - Google Patents

Abstract

PURPOSE:To carry out coating excellent in adhesive strength, wear resistance, and heat resistance by successively forming a film of an Si-containing substance of a specific thickness and a film of a substance containing Ce, Ta, Zn, etc., on the surface of a plastic base material. CONSTITUTION:Simple-substance Si or Si-containing oxide is vacuum-deposited as a first layer to 10-10000Angstrom film thickness on the surface of a base material composed of plastic, such as poly methyl methacrylate. Subsequently, a dielectric substance which contains Ce-containing oxide or fluoride, Ta-containing oxide, and Zn-containing oxide or sulfide by >=60wt.% is vacuum-deposited onto the above surface, by which a second film is formed. Then, coating is carried out by using the first and the second film mentioned above as base coat films. By this method, a conductive film, an optical film, etc., excellent in adhesive strength, wear resistance, and heat resistance can be formed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for coating plastics, and more specifically, the present invention relates to a coating method for plastics, and more specifically, a method for coating plastics using a vacuum evaporation method to coat dielectric materials formed in two layers as a base coat film. , relates to a plastic coating method that can form a deposited film that has excellent adhesion to a substrate when a film corresponding to various purposes and uses is formed on the film.

[Prior art and its problems] Plastic materials with excellent translucency are lightweight, have excellent mechanical strength, are easy to work with, and can be designed freely, so they have been used particularly in the optical field as a substitute for glass. It is widely used in etc.

Transparent plastics that are currently widely used include thermoplastic polyvinyl chloride (PVC) and polystyrene (
PS), polycarbonate (PC), polymethyl methacrylate (PMMA), and thermosetting polydiethylene glycol bisallyl carbonate (CR-39).

Among these plastics, polymethyl methacrylate (PMMA) is used as an optical component due to its transparency, lightweight,
It has excellent processability and impact resistance, and especially has the best light transmittance compared to other resins.

However, this plastic substrate has two major drawbacks; the first is that its surface is easily damaged by friction, scratches, etc. due to its low surface hardness. The second method is to form a metal layer or a metal compound layer on the plastic base material in order to impart optical properties,
This is often used as a mirror surface or as a conductive film, but problems such as peeling cracks (cracks in the film) occur during adhesion heat resistance tests.

Therefore, various methods have been proposed to improve these drawbacks.

One of the methods is to form an undercoat as a base layer (formed by ultraviolet curing method, electron beam irradiation curing method, thermosetting method, etc.) in order to increase the adhesion strength when forming a metal vapor deposition pattern on a plastic base material. Alternatively, there is a method of applying a top coat as a protective film. However, undercoats and topcoats can be uneven or have foreign matter attached to them, so it is necessary to maintain a clean level during the manufacturing process, making it difficult to maintain a manufacturing environment and creating difficulties in mass production. there were. In addition, the film thickness of the film is usually 3
~51J! Since it is coated within the It range, it is not suitable for applications that require surface precision.

Therefore, several methods have been reported to improve adhesion and hard coat properties by forming undercoat films and topcoat films using vacuum evaporation methods. However, sufficient adhesion strength could not be obtained, and no product was found to be suitable for practical use.

This is thought to be due to the fact that the plastic base material has a higher water content and coefficient of linear expansion than inorganic substances such as glass, and also has a higher residual stress generated when molded. Therefore, when a heat cycle test at +70 to -30°C is performed on a film formed on a plastic base material,
As the base material expands and contracts, hairs may cause cracks in the metal, and the film may peel off.

As means for solving the problems of vacuum evaporation as described above, there are a plasma ion blating method and an ion bombardment cleaning method performed before evaporation. Both of these are achieved by introducing a gas (reactive gas, inert gas), causing a gas discharge (excitation) in a vacuum, and ionizing the evaporated matter that enters the substrate from the evaporation source, resulting in characteristics that are difficult to obtain with vacuum evaporation. can form a thin film of

Methods for generating gas discharge include the matrix method, RF excitation method, multi-cathode method, holocathode method, and bias prog method, all of which use excited reactive or inert gas ions, excited particles, or radicals. Particles etc. are generated in the vacuum chamber. These charged particles (evaporation molecules) are then accelerated and attracted by the voltage on the substrate side, forming a film with excellent adhesion on the plastic substrate, but on the other hand, they adhere to the vapor deposition tank. Other vapor deposition molecules will also be sputtered together. Therefore, in a vacuum chamber where evaporation is repeated many times, these ions that should not be activated increase and may enter the intended film, causing a decrease in adhesion. .

From the above points, it has been difficult and difficult to form a metal film on a plastic substrate directly by vacuum deposition or to form a coating film with good adhesion to the surface.

[Means for Solving the Problems] The present inventor has made extensive efforts with the aim of forming an optical film or a conductive film that can meet various purposes on plastic lenses, which have recently seen a rapid increase in demand as an alternative to glass. As a result of research, when forming a target metal, dielectric material, etc. on the surface of a plastic base material by vacuum evaporation, a silicon (Si)-containing material is formed as a base film, and then a cerium (Ce)-containing material is formed on the base film. ) containing substance, tantalum (Ta)
The present invention was completed by discovering that adhesion, abrasion resistance, and heat resistance can be significantly improved by forming a zinc (Zn)-containing substance or a zinc (Zn)-containing substance.

That is, the present invention provides the following [1] on the surface of a plastic base material.
After forming a first film by vacuum evaporating a substance consisting of 10 to 10,000 layers in thickness, a second film is formed by vacuum evaporating a substance consisting of the following [2] on the first film. , a plastic coating method characterized in that the first and second films are used as base coat films.

■ Simple silicon or silicon-containing oxide ■ Dielectric material containing 60% by weight or more of cerium-containing oxide or fluoride, tantalum-containing oxide, or zinc-containing oxide or sulfide The present invention particularly applies to cerium (ce)-containing materials. This was based on the knowledge that these materials are compatible with both plastics and silicon, and with this base film interposed, a conductive film of the desired metal, dielectric material, etc. is deposited in a single layer or in multiple layers, The optical film shows excellent results in adhesion, abrasion resistance, heat resistance tests, etc.

Plastic substrates used in the method of the present invention include, for example, thermoplastic resins such as polymethyl methacrylate, polystyrene, polycarbonate, polyvinyl chloride, copolymers of methyl methacrylate and other vinyl heptamers, and thermosetting resins. Examples of such resins include polydiethylene glycol bisallyl carbonate, etc., and plates or lenses manufactured from these resins by injection molding or cast molding. Among these, polymethyl methacrylate, which has excellent translucency, is particularly preferred.

When forming a film on the surface of these plastic substrates by vacuum deposition, there may be stains such as burns, fingerprints, and oil on the surface of the substrate, so do not use neutral detergents, Freon, etc. Clean, degrease, and dehydrate the surface. Furthermore, since some types of plastic substrates have very high water absorption rates, it is desirable to pre-dry them after washing.

The base material that has undergone the previous step is subjected to vacuum evaporation, and the evaporation equipment used at this time may be of any known type, and the exhaust system may be either a diffusion pump or a cryopump, and is not particularly specified. Further, as the conditions at this time, it is desirable that the starting degree of vacuum is 2×10 −5 Torr or less.

Furthermore, examples of dielectric materials used in the method of the present invention include titanium dioxide (Ti02), zirconium oxide (ZrO2), alumina (Al2O3>, silicon dioxide (5i02), and magnesium fluoride ()).
Examples include I(]F2) and mixtures of other dielectric substances, but the substance is not particularly limited.

Also, as metals, M, Cr, 8g, Cu, Bi
, In.

Examples include Hg, Ni, Se, Te, Ti, AU, and mixtures of other metals, but the substance is not particularly limited.

[Example] Next, examples of the present invention will be described.

Examples 1-2. Comparative Examples 1 to 3 A PMMA resin having a refractive index of 1.492 (at 20°C) was used as a base material, and after being subjected to ultrasonic cleaning, it was annealed and dried, and then attached to a dome in a vacuum evaporation device. , vacuum was applied. At this time, the substrate temperature was set at 70° C., and the vacuum was evacuated to a degree of vacuum of 2.0×10 −5 TOrr.

Next, an antireflection layer was formed under five conditions shown in Table 1 below.

Environmental tests were conducted on each of the obtained acrylic plates under the following conditions.

■Tape test: Peeling test of adhesive tape 20 times ■Heat test: Leaving in an atmosphere at a temperature of 70°C for 48 hours.The results are also shown in Table 1. In addition, in the table, the number of layers indicates the number of layers from the base material.

(The following is a blank space) As can be seen from Table 1, Examples 1 and 2 both showed good results in terms of adhesion and heat resistance.

In Comparative Example 1, both adhesion and heat resistance were poor, and in Comparative Example 2, the adhesion was good because the Ce-containing substance was used directly on the substrate, but since no Si was interposed,
A minute rack occurred during the heat test. Comparative example 3
, the physical thickness of the first layer 5i02 is i i
, There were too many people (300 people), so the close contact was poor.

Partial cross-sectional views of the deposited films 1q in each Example and Comparative Example are shown in FIG. 1(a) (Example 1) and FIG. 1(b)(
Example 2), Figure 1(C) (Comparative Example 1), Figure 1(d)
(Comparative Example 2) and FIG. 1(e) (Comparative Example 3).

In the figure, 1 is the base material, 2 is 5i02.3 is CeF3.4 is H
(JFz, 5 is CeO2, 6 is CEO2 + TiO2 (
20%).

Further, FIG. 2 shows a diagram of these optical characteristics. In the figure, A-
B and C-E are Examples 1 and 2 and Comparative Examples 1 and 2.3, respectively.
corresponds to Note that F indicates the reflectance when there is no antireflection layer.

Example 3. Comparative Example 4 In this example, a comparative test was conducted between the case where the base film according to the present invention was interposed and the case where the base film according to the present invention was not interposed when forming Gicrocoat (10 alternating layers of ZnS/)fgF2).

Evacuating under the same conditions as in Example 1, vapor deposition was performed with the following film configuration, and an adhesion test was conducted.

Example 3 Base material I 5i02/CeO2/ZnS/H(J
F2 / ZnS / HgF2 / ZnS / H! J
F2 / ZnS/ MOF2 /2nS/ H(]F
A 12 layer coating including 2 I air and a base coat film was performed.

The film thickness is 5i02, and CEO2 is each 1/8・λ0 (λo=
550nm) ZnS and HgF2 are each 1/4・λ0 (λo=55
0nm) (CeO2 used at this time was CeO2+Ti02(
Comparative Example 4 Base material I ZnS/H (lFz/ZnS/Hg
F2/ZnS/M(JF2/ZnS/H(]F2
/ZnS/HClF2 l air and 10 layers coating was performed.

The film thickness was 1/4·λ0 (λo=550 nm). When the performance of the obtained acrylic resin plate with the dichroic film was evaluated, the results shown in Table 2 were obtained.

Table 2 Book 2) Adhesion test: When lines are made with a cutter knife at 1 mm intervals of ioxlomm on the dichrome film layer and cellophane tape is applied and peeled off, this is the number of pieces that peeled off (molecular is the remaining number).

83) Imaging test: Single-chord harmonic imaging (2
0 to 60H2 cycles) for 20 minutes each in the vertical and horizontal directions.
It will last for a total of 1 hour. At this time, the case where the deposited film does not fall off the substrate is judged as good, and the case where it falls off the substrate is judged as bad.

Example 4 In this example, when performing metal coating, a base film (5i0
2/CeF3) was interposed.

A square plate (height: 100 mm) of thermosetting resin polydiethylene glycol bisallyl carbonate (CR-39).

(width: 100 mm, board thickness: 3 mm) was ultrasonically cleaned using neutral detergent, pure water, and Freon. Then, it was loaded into a vacuum chamber with the vapor deposition side facing down. While maintaining the substrate temperature at 70 to 80°C, the temperature was evacuated to 2X10-5 orr, and after evaporating 5i02 as a base film with a thickness of 100 layers and 100% CeF3 with a thickness of 200 layers, metals Cu and Cr were deposited with a thickness of 1000 layers each. It was coated with a film thickness of

An adhesion test was conducted under the same conditions as in Example 3, and the results showed an excellent result of 100/100.

Examples 5 and 6 In this example, 5i was used as a base film on the acrylic molded product.
02/Cho a205 (Example 5) and 5i02/ZnO (Example 6)
The heat resistance of the material was investigated.

Thermoplastic resin polymethyl methacrylate (P)f)f
A square plate (100 mm x 100 mm, plate thickness: 3 mm) was ultrasonically cleaned with neutral detergent, pure water, and chlorofluorocarbons, and then loaded into a vacuum chamber with the deposition surface facing down.

Thereafter, the vacuum was evacuated under the same conditions as in Example 4, and vapor deposition was performed as shown in Table 3.

(Left below) Table 3 λo = 550nllll (5500 people) After deposition, 4
After 8 hours had elapsed, a heat cycle test as shown below was conducted, but in both Examples 5 and 6, no cracks were generated and no abnormalities were observed.

Heat cycle test conditions: +70 to -30°C x 10 cycles The above heat cycle test conditions are illustrated in FIG. 3. In the figure, the vertical axis represents temperature and the horizontal axis represents time.

[Effects of the Invention] As explained above, the optical film, conductive film, etc. deposited on a plastic base material by the coating method of the present invention has excellent adhesion and abrasion resistance, and does not reduce the surface precision of the base material. However, the desired optical properties, electrical properties, etc. can be satisfied, and especially excellent results are shown in terms of adhesion.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a vapor deposited film obtained according to an example of the present invention, FIG. 2 is a diagram showing their optical characteristics, and FIG. 3 is a diagram showing heat cycle conditions.

Claims (1)

[Claims] (1) After forming a first film by vacuum-depositing a substance consisting of the following [1] to a film thickness of 10 to 10,000 Å on the surface of a plastic base material, a substance consisting of the following [2] is deposited on the first film. vacuum depositing a substance to form a second film;
A method for coating plastics, characterized in that the film is used as a base coat film. [1] Single silicon or silicon-containing oxide [2] Dielectric material containing 60% by weight or more of cerium-containing oxide or fluoride, tantalum-containing oxide, or zinc-containing oxide or sulfide