JPH0452288B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a surface-modified plastic with excellent chemical resistance and weather resistance on the surface and improved wettability, adhesiveness, etc., and a method for producing the same. It is.

(Prior art) General-purpose plastics such as polyethylene, polystyrene, polycarbonate, and polymethyl methacrylate are easy to measure, process and mold, and are inexpensive, making them useful as building interior materials and vehicle components. . Transparent plastics are also in high demand as materials for optical equipment such as glasses, cameras, and lenses, as well as household and office materials such as windows, doors, cupboards, and display cases. However, these plastics
Many materials are easily attacked by organic solvents, and are easily attacked by light.
It has problems such as deterioration due to exposure to ozone, rain, etc., and also being easily scratched due to its low surface hardness.

As a solution to these problems, various attempts have been made to coat the surface of plastic with fluororesin or silicone resin, which have excellent chemical resistance and weather resistance, but protective films made of these resins are However, due to its low polarity and extremely low surface wettability, it had the disadvantage of poor adhesion to other plastics. For this reason, even if a protective film is formed on the surface of the plastic to be protected, water or other impurities may enter the interface between the protective film and the plastic, causing the protective film to peel off, or these substances may enter the interface. The current situation is that even if the protective film does not penetrate, it is easily peeled off when a strong peeling force is applied to the protective film.

In addition to the above methods, protective film formation methods include a wet method in which the plastic molded product to be protected is immersed in a solution containing a resin and the solvent is evaporated to form a resin film on the plastic surface, and a plasma method. A dry method using polymerization is also known, but good adhesion of the protective film is not always obtained. Examples of these methods include, for example, a method for forming a protective film using an organic silicon compound as a raw material, as described in Japanese Patent Application Laid-open No. 52-65575, and an attempt to improve adhesion by undercoating boron trifluoride under the protective film. A method of undercoating with an aromatic compound is described in JP-A-54-7474, and a method of undercoating with an aromatic compound is described in JP-A-54-7474.
Although these methods are disclosed in Japanese Patent No. 58-147431, the present invention has created a protective film with good adhesion using a method different from these methods.

(Object of the invention) The present invention provides excellent chemical resistance and weather resistance, as well as improved wettability and adhesiveness, by forming a film on the surface of the plastic substrate to be protected.
Furthermore, it is an object of the present invention to provide a surface-modified plastic having scratch resistance and optionally transparency as well as a method for producing the same.

(Structure of the Invention) The surface-modified plastic of the present invention consists of a plastic base material, an adhesive side to the plastic base material and a non-adhesive side provided on the surface of the plastic base material. The surface modified film is made of two or more compounds selected from compounds containing unsaturated hydrocarbon bonds and organic nitrogen-containing compounds or organic silicon-containing compounds as raw materials. , is characterized in that it is formed by plasma polymerization in the presence of a non-polymerizable gas other than an inert gas.

The surface-modified plastic of the present invention uses two or more types of raw materials consisting of at least one type of compound containing an unsaturated carbon bond and at least one type of organic nitrogen-containing compound or organic silicon-containing compound, and supplies each of these raw material compounds. By plasma polymerizing in the presence of a non-polymerizable gas other than an inert gas, the amount of which is varied with respect to the polymerization time, the surface of the plastic substrate is bonded to the adhesive side and the non-adhesive side to the plastic substrate. It can be manufactured by forming a surface-modified film that has different chemical composition or physical properties such as wettability on the surface side.

In the surface-modified membrane of the present invention, the internal chemical composition of the membrane can be changed continuously or stepwise in the thickness direction depending on the method of supplying the raw material compounds.

Compounds that can be used as raw materials for forming a surface-modified film in the present invention include:
Examples of compounds containing unsaturated carbon bonds include ethylene, acetylene, propylene, butadiene,
Examples include benzene, toluene, xylene, ethylbenzene, and styrene.

Examples of organic nitrogen-containing compounds include acetonitrile, acrylonitrile, aniline, pyridine, and vinylpyridine.

On the other hand, examples of organic silicon-containing compounds include tetramethylsilane, trimethylmethoxysilane,
Dimethyldimethoxysilane, trimethoxymethylsilane, tetramethoxysilane, ethoxytrimethylsilane, diethoxydimethylsilane, triethoxymethylsilane, tetraethoxysilane, vinyltrimethylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyl Examples include triacetoxysilane, tetravinylsilane, hexamethyldisiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane.

In the present invention, in polymerizing the above-mentioned raw material compounds, it is necessary to have a non-polymerizable gas such as oxygen, nitrogen, ammonia, water vapor, etc. present. Such a non-polymerizable gas does not by itself form a polymerization product in the plasma even if it is introduced into the polymerization reactor as a gas alone. However, judging from conventional plasma surface treatment methods for plastics to improve the wettability and adhesion of plastic surfaces, these non-polymerizable gases, when excited in plasma, for example, It is thought that polymerization active species including radical species are generated on the surface of the plastic by reacting with the plastic inside. It is also believed that the above compound containing an unsaturated carbon bond reacts with the excited non-polymerizable gas to form a polymerized product that has good adhesion to the plastic surface.

Furthermore, by plasma polymerizing an organic nitrogen-containing compound or an organic silicon-containing compound in the presence of a non-polymerizable gas, C-N, Si-
O bonds and the like are introduced, and the scratch resistance or transparency of the surface-modified film is improved. In particular, the above effect is remarkable in plasma polymerization of compounds containing unsaturated carbon bonds and organic nitrogen-containing compounds or organic silicon-containing compounds in the presence of oxygen.

In the present invention, the plastic that serves as the base material on which the surface-modified film is formed is not particularly limited, but includes, for example, styrene resin, vinyl chloride resin, vinyl chloride resin, polyolefin resin such as polyethylene and polypropylene, acrylic or methacrylic resin. resin, ionomer, polycarbonate,
Examples include epoxy resin and unsaturated polyester resin. These plastic substrates are
Its shape is not particularly limited, such as a sheet, film, or molded product.

In order to obtain a surface-modified plastic with excellent water resistance and adhesion, a compound with the same or similar chemical composition to the base plastic should be selected as one of the raw materials for the surface-modified film. is preferred. For example, if the base material is styrene resin,
Styrene is selected as one of the raw materials, and at the beginning of polymerization, styrene alone or a combination composition with a high amount of styrene is supplied into the reaction vessel, and styrene is plasma polymerized in the presence of a non-polymerizable gas to form a plastic substrate and surface. By ensuring adhesion with the modified film and further performing plasma polymerization of the organic silicon-containing compound in the presence of a non-polymerizable gas, a styrene resin with improved surface water resistance or scratch resistance is obtained. The surface-modified plastic thus obtained does not peel off easily because the surface-modified film is bonded to the base plastic with a substance of the same or similar chemical composition.

In the present invention, when the base plastic is transparent and it is desired to obtain a transparent surface-modified plastic, it is possible to obtain a transparent and optically-modified plastic by appropriately selecting the raw material compound and the thickness of the surface-modified film. It is also possible to form plasma polymerized membranes with excellent properties. However, when the film thickness is usually 1 μm or less, transparency is good, but physical and mechanical strength such as scratch resistance decreases. Therefore, especially when the purpose is a surface-modified plastic with physical properties such as scratch resistance,
The film thickness is preferably 1 μm or more.

In the present invention, the conditions for plasma polymerization are not particularly limited, and conditions conventionally used in this type of field can be used as they are. The surface-modified film of the present invention is not limited to the above description, and a polymer film of any thickness can be formed by arbitrarily shortening or extending the polymerization time.

(Example) The present invention will be explained below with reference to Examples.

Example 1 A polystyrene plate (thickness: 5 mm) was placed as a plastic substrate in a bell jar type reactor, and then the pressure inside the reactor was reduced to 0.01 Torr or less. After that, oxygen and styrene were first introduced into the reactor, and plasma polymerization was performed at a constant pressure of 0.1 Torr, an input of 100 W, and a high frequency of 13.56 MHz. This plasma polymerization was carried out by introducing hexamethyldisiloxane into the reactor in place of styrene under the above-mentioned constant pressure as the polymerization time progressed. At this time, the composition ratio of the raw materials supplied into the reactor was continuously changed as shown in FIG. Plasma polymerization was performed in this manner for about 36 minutes to form a surface-modified film on the surface of the polystyrene plate.

Formed and bonded to the surface of a polystyrene plate,
This surface-modified film did not peel off even when a peel test was performed using an adhesive tape (cellophane tape). In addition, when the surface wettability was measured using a surface contact angle measuring device, the contact angle of water (distilled water) on the surface of the polystyrene plate was 85°, but that of the surface of the surface-modified polystyrene plate was It was 90°. Next, scratch resistance was evaluated using a surface property tester.
When a scratch test was conducted on the surface-modified film coated and uncoated parts of a polystyrene plate using a sapphire needle under a load of 3g to 5g, the surface-modified film-coated parts were more resistant than the uncoated parts. The scratch resistance was good. The thickness of the surface modified membrane is 1 μm.
It was transparent and warm.

Example 2 A polycarbonate plate was used as a plastic substrate, and a plasma polymerized film was formed and adhered to the surface of the plate in the same manner as in Example 1 using the same raw materials.

The surface modified film formed on the surface of the polycarbonate plate by plasma polymerization in this example is transparent;
Further, even when a peel test using tape was performed, no peeling occurred. The thickness of the surface modified film formed was 1 μm. The polycarbonate plate surface-modified in this way was more water repellent and had better scratch resistance than the polycarbonate plate that was not surface-modified.

Example 3 Surface modification was carried out in the same manner as in Example 1, except that a polystyrene plate was used as the plastic base material and the composition ratio of raw materials supplied into the reactor during plasma polymerization was continuously changed as shown in Figure 2. Manufactured plastic.

The surface modified film formed on the surface of the polystyrene plate by plasma polymerization in this example is transparent, water resistant,
It had excellent adhesive properties. The film thickness was 1 μm.

Example 4 A surface-modified polystyrene plate was manufactured in the same manner as in Example 3 using the same raw materials except that nitrogen was used instead of oxygen as the non-polymerizable gas.

The surface modified film formed on the surface of the polystyrene plate by this plasma polymerization was transparent, had good water resistance and adhesion, and also had scratch resistance.

Example 5 A surface-modified polystyrene plate was produced in the same manner as in Example 4, except that acrylonitrile was used instead of hexamethyldisiloxane. However, the composition ratio of the raw materials in the plasma polymerization was continuously changed as shown in FIG.

The contact angle of water on the surface of the polystyrene plate surface-modified by this plasma polymerization method was 60°. Moreover, the adhesion of this surface modified film was good.

(Effects of the Invention) The present invention does not require special pre-treatment of the plastic material whose surface is to be modified, and since no solvent is used for modification, the plastic material to be treated is It's not limited either.

According to the present invention, the raw material compound to be plasma polymerized is appropriately selected from a compound containing an unsaturated hydrocarbon bond and an organic nitrogen-containing compound or an organic silicon-containing compound, and by selecting the combination, transparency and water resistance can be achieved. It is possible to obtain surface-modified plastics with excellent adhesiveness, adhesion, abrasion resistance, and even chemical resistance, which has many excellent effects such as the ability to use inexpensive general-purpose plastics for higher-grade applications. play.

[Brief explanation of drawings]

FIGS. 1 to 3 are graphs showing the non-polymerizable gas used and the polymerization time and composition ratio of raw material compounds used in each example.

Claims (1)

[Scope of Claims] 1. A plastic base material and a surface modification provided on the surface of the plastic base material in which the chemical composition or physical properties such as wettability are different between the adhesive side and the non-adhesive side to the plastic base material. The surface modified film consists of a
By plasma polymerizing two or more compounds selected from compounds containing unsaturated hydrocarbon bonds and organic nitrogen-containing compounds or organic silicon-containing compounds in the presence of a non-polymerizable gas other than an inert gas. A surface-modified plastic characterized by being formed by 2. The surface-modified plastic according to claim 1, wherein the chemical composition of the surface-modified film changes continuously in the thickness direction. 3. The surface according to claim 1 or 2, wherein the compound containing an unsaturated hydrocarbon bond is selected from ethylene, acetylene, propylene, butadiene, benzene, toluene, xylene, ethylbenzene, and styrene. Modified plastic. 4. The surface-modified plastic according to claim 1 or 2, wherein the organic nitrogen-containing compound is selected from acetonitrile, acrylonitrile, aniline, pyridine, and vinylpyridine. 5 The organic silicon-containing compound is tetramethylsilane,
Trimethylmethoxysilane, dimethyldimethoxysilane, trimethoxymethylsilane, tetramethoxysilane, ethoxytrimethylsilane, diethoxydimethylsilane, triethoxymethylsilane, tetraethoxysilane, vinyltrimethylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl The surface according to claim 1 or 2, characterized in that the surface is selected from trichlorosilane, vinyltriacetoxysilane, tetravinylsilane, hexamethyldisiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane. Modified plastic. 6. Surface-modified plastic according to claim 1 or 2, characterized in that the non-polymerizable gas is selected from oxygen, nitrogen, ammonia, water vapor and mixtures thereof. 7. Claims 1 or 2, characterized in that the plastic base material is selected from the group consisting of styrene resin, vinyl chloride resin, polyethylene, methacrylic resin, ionomer, polycarbonate, epoxy resin, and unsaturated polyester resin. Surface-modified plastics as described in Section. 8 Using two or more types of raw materials consisting of at least one type of compound containing an unsaturated carbon bond and at least one type of organic nitrogen-containing compound or organic silicon-containing compound, and changing the supply amount of each of these raw material compounds with respect to the polymerization time. By plasma polymerizing in the presence of a non-polymerizable gas other than an inert gas, the chemical composition or A method for producing surface-modified plastics, characterized by forming a surface-modified film that has different physical properties such as wettability.