JPH0251444A - Adhesive sheet for glass coating and coating method - Google Patents

Abstract

PURPOSE:To easily apply glass coating to an inorg. object in good yield and high accuracy of positioning by applying pressure-sensitive layers to both surfaces of a glass powder sheet having glass powder and org. binder as main component. CONSTITUTION:As occasion demands, 100 pts.wt. usual glass powder (usually 0.1-50mum, preferably 0.5-10mum particle size) such as PbO-B2O3-SiO2 glass is added with 1-50 pts.wt. inorg. powder such as SiC and compounded with 5-40 pts.wt. org. binder (especially preferably acrylic resin) to prepare the glass sheet having 10-200mum thickness. The ordinary temp. pressure-sensitive layers (having the thermal decomposition temp. higher than that of the org. binder) are applied to both surfaces of the sheet. On the one surface, self-supporting material is temporarily attached utilizing the adhesive property and the sheet is pressure- adhered on the inorg. object through the adhesive layer on the other surface. Then, after stripping the self-supporting material off, the glass coating layer is produced by burning.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a glass powder sheet for applying glass coating to the surface of an inorganic object made of ceramic, metal, glass, etc., and a glass powder sheet using the above sheet. The present invention relates to a coating method.

(Prior art) Conventionally, it has been used for the purpose of imparting properties such as surface smoothness, wear resistance, corrosion resistance, surface hardness, and electrical insulation to inorganic objects such as ceramics, metals, and glasses, and for decoration of appearance. Various glass coatings are used for this purpose.

The mainstream method has been to use a paste containing glass powder to screen print onto an inorganic object and then bake it. However, the following points have been pointed out as problems with this method.

(1) It is necessary to print several times to obtain the required thickness,
Production efficiency is poor.

(2) It is difficult to screen print onto an object having an irregular cross section such as a curved surface or uneven surface.

(3) The glass paste used must be easy to screen print, but its adjustment is not easy, and there are restrictions on the type and composition of materials.

There are other methods such as spray coating, dipping, and brush coating, but these have drawbacks such as uneven coating thickness, poor yield, and low productivity.

Therefore, as a method to solve these difficulties and to easily control the thickness in a simple process, a so-called sheet method has been proposed in which a sheet is prepared in advance using glass powder and an organic binder, and the sheet is laminated and pressed and then fired. There is. However, it is difficult to obtain sufficient sheet strength, resulting in poor lamination efficiency and difficulty in automating lamination. In particular, when the thickness of the coating layer is made thin, the sheet itself is also thin, so there is a problem that the sheet lacks stiffness and the lamination position accuracy cannot be achieved. Sheet strength can be improved to some extent by increasing the content of organic binder in the sheet, but on the other hand, the release of decomposed gas becomes difficult and carbon tends to remain, which tends to worsen the appearance after firing. In practice, it is difficult to improve the strength simply by adjusting the binder content.

(Problem to be Solved by the Invention) The problem to be solved by the present invention is to solve the above-mentioned difficulties of the prior art. It is an object of the present invention to provide an adhesive sheet for glass coating that can be applied and automated.

(Means for Solving the Problems) The present invention has been made as a result of intensive research to achieve the above object, and has the purpose of achieving the above-mentioned object by applying a powder to both sides of a glass powder sheet containing glass powder and an organic binder at room temperature. An adhesive layer with pressure-sensitive adhesive properties is provided, and this adhesive property is used to temporarily attach a self-supporting material to one side, and the self-supporting material is pressed onto an inorganic object via the adhesive layer on the other side. This problem can be solved by peeling off the glass and then firing it to form a glass coating layer.

(Structure and operation of the invention) In the present invention, in forming a glass coating layer on the surface of an inorganic object, a glass powder sheet containing glass powder and an organic binder as main components is applied to the inorganic object using a pressure-sensitive adhesive layer. There is no need to employ conventional methods such as printing or spraying in order to press-bond the material, and therefore all the various problems caused by these methods can be avoided. In other words, since there is no need to dry the paste, production efficiency is increased, and it is also easier to coat objects with curved or uneven surfaces with glass.

In addition, there is no need to consider screen printability at all, and there are no restrictions on the selection of material types or formulations, and a wide range of materials can be used as appropriate. Furthermore, since it uses a pressure-sensitive adhesive layer, it can be sufficiently pressed with a weak force, and can be applied to fragile inorganic objects.

In addition, at least one of the pressure-sensitive adhesive layers has a higher thermal decomposition temperature than the organic binder forming the glass powder sheet. Even if the organic binder disappears, the adhesion is still good, making it difficult for the glass powder sheet to peel off.

Furthermore, since a pressure-sensitive adhesive layer is provided on both sides of the glass powder sheet, by temporarily attaching a self-supporting material such as a release-treated film to one side, it is possible to give stiffness to the thin glass powder sheet. As a result, it becomes extremely easy to handle when pasting on an inorganic object, and the precision of pasting also improves.

In the present invention, ordinary Pb0-Bz is used as the glass powder.
Owl-3to type glass, and Nag OBz 02 S jog type, B for lead-free types.
Known materials such as a OCa OS i Oz system can be used. The size of the glass powder at this time is usually 0.
．． The thickness is about 1 to 50 am, preferably about 0.5 to 10 μm.

Further, if necessary, an inorganic powder may be added to the glass powder in an amount of 40% by weight or less. This inorganic powder is used for the purpose of improving surface properties, and its particle size is usually 0.1 to 100.
μm Preferably about 0.5 to 50 μm. The amount used is about 1 to 50 parts by weight per 100 parts by weight of glass powder. Preferred inorganic powders are SiC, S
iN4, BN, Aj2t 03, Zr0z, S j
Examples include og, Tilt, BaTi0z, etc.

On the other hand, as the organic binder, synthetic polymers such as hydrocarbon resins, vinyl resins, acetal resins, acrylic resins, styrene resins, polyester resins, and polyurethane resins, and semi-synthetic polymers such as cellulose resins can be used. Hydrocarbon resins, acrylic resins, acetal resins, and cellulose resins are preferred because they are easily thermally decomposed, and acrylic resins are particularly preferred. The amount to be blended varies depending on the specific gravity and particle size of the glass powder or inorganic powder, but it is preferably in the range of 5 to 40 parts by weight per 100 parts by weight of the glass powder. If the amount is too low, the strength of the powder sheet will be reduced, resulting in significantly poor workability. Further, in the present invention, a dispersant can also be used to improve uniform mixing of the glass powder or inorganic powder and the organic binder. As the dispersant in this case, various usual surfactants as well as other fatty acids, fatty acid esters, fish oils, acrylic oligomers, etc. can be used. The amount of the dispersant used in this case is about 0.01 to 10 parts by weight, preferably about 0.1 to 2 parts by weight, based on 100 parts by weight of the total amount of glass powder and inorganic powder.

When preparing a powder sheet, additives such as a suitable solvent and antifoaming agent are added to the above composition components, and a powder sheet can be prepared by a conventional doctor blade method or the like.

That is, a powder sheet with good thickness accuracy can be obtained by mixing glass powder, an organic binder, a solvent, and optionally additives such as an inorganic powder dispersant and a mold release agent in a ball mill, and casting with a doctor blade. can. Furthermore, by sufficiently defoaming the slurry before casting, it is possible to prevent air bubbles from remaining inside the sheet.

A major feature of the present invention is that pressure-sensitive adhesive layers are provided on both sides of the glass powder sheet. In order to obtain a glass coating layer with good appearance and adhesion after firing, it is necessary that the glass powder sheet and the inorganic object are in sufficient contact with each other during lamination, and also that the organic binder in the powder sheet is removed during firing. It is important that the glass powder sheet does not peel off before it disappears. Therefore, it is preferable that the thermal decomposition temperature of the pressure-sensitive adhesive layer on the side that is pressed onto the inorganic object is set higher than the thermal decomposition temperature of the organic binder constituting the powder. If a pressure-sensitive adhesive layer is not formed, or if the thermal decomposition temperature of the pressure-sensitive adhesive layer is lower than that of the organic binder, the powder sheet may peel off from the inorganic object, or the edge portion may shrink. However, the position where the coating is applied may be misaligned.

On the other hand, plastic film or sheet, paper, etc. that has been subjected to release treatment on the side of the pressure-sensitive adhesive layer that is not pressure-bonded to the inorganic object,
By temporarily attaching a self-supporting material made of a stiff support such as metal foil, it is possible to facilitate the handling of the aluminous object and improve the accuracy of the attachment. In other words, if the adhesive sheet for glass coating is too thin and stiff, there is a risk that air will be trapped at the interface when it is bonded to an inorganic object.
By giving it a waist, it can be pasted sequentially from one end, eliminating air entrapment. After the pasting process is completed, the self-supporting material is peeled off and subjected to the subsequent firing process, so the pressure-sensitive adhesive layer used on this surface can be the same as the other side, but at a thermal decomposition temperature. It is preferable to use one with a low

These high and low thermal decomposition temperature pressure sensitive adhesives include acrylic pressure sensitive adhesives, polyvinyl ether pressure sensitive adhesives, diene rubber based pressure sensitive adhesives, and neoprene pressure sensitive adhesives. For example, an ordinary acrylic pressure-sensitive adhesive with a low thermal decomposition temperature may be selected, and an ordinary acrylic adhesive with a high thermal decomposition temperature such as acrylonitrile may be selected as appropriate from adhesives. An example of the method is to use a copolymerized monomer that forms a polymer with a high thermal decomposition temperature, or a blend of an appropriate amount of a resin with a high thermal decomposition temperature such as a phenol resin or a xylene resin.

When forming a pressure-sensitive adhesive layer on a glass powder sheet, a pressure-sensitive adhesive solution is applied onto a release liner such as release-treated paper or polyethylene terephthalate film using a roll coater, spray, etc., and dried. Although a method of transferring the powder onto the surface of the powder sheet is a common method, the method is not necessarily limited to this method. For example, it may be directly applied by spraying or the like. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive force will be low, and if it is too thick, the amount of pyrolysis gas generated will increase, making it impossible to obtain sufficient adhesion. Therefore, it is preferably in the range of 1 to 100 μm.

The adhesive sheet for glass coating produced by the above method can be easily bonded to an inorganic object through a pressure-sensitive adhesive layer having a high thermal decomposition temperature.

This crimping operation will be explained in more detail with reference to the drawings as follows. However, as a glass powder sheet, 1. An example is given in which a self-supporting material that has been subjected to a release treatment is temporarily attached. First, as shown in Figure 1 (a), a pressure-sensitive adhesive layer (2) with a low thermal decomposition temperature and a pressure-sensitive adhesive layer (2') with a high thermal decomposition temperature are applied on both sides of a glass powder sheet (1), respectively. A self-supporting material (3) that has been subjected to a release treatment is temporarily attached to the side of the pressure-sensitive adhesive layer (2) having a lower thermal decomposition temperature, and this is pressure-bonded to the inorganic object (4). When crimping, the first
As shown in Figure (B), the pressure-sensitive adhesive layer with a high thermal decomposition temperature (
2) onto the inorganic object (4). At this time, it is preferable to apply heat and pressure using a hot roll, hot press, etc., since even better adhesion can be obtained. Next, the same figure (
As shown in c), the self-supporting material (3) is peeled off.

After peeling off the surface, it is fired according to a conventional method.

In this invention, the inorganic object can be made of a wide variety of materials as long as it does not deteriorate during the next firing process. Typical examples include ceramic, glass, and metal, with ceramic being particularly preferred. There is.

The thus obtained inorganic substance laminate in which the adhesive sheet for glass coating according to the present invention is laminated is subjected to a firing treatment at high temperature to thermally decompose and eliminate organic substances such as organic binders and pressure-sensitive adhesives, A glass coating layer can be formed with high bonding strength and without peeling, disconnection, misalignment, etc. of the coating layer.

The heating temperature in the above firing process varies depending on the type of glass powder used, but is usually 400 to 1400°C.
It may be appropriately set within a certain range depending on the type of each powder.

(Effects of the Invention) As described above, since the present invention uses an adhesive sheet for glass coating that has been formed into a sheet in advance, unlike the case of using glass paste, drying time is not required, resulting in high production efficiency and screen printing. There are no restrictions on the selection of materials based on their printing properties. In addition, since a pressure-sensitive adhesive layer is provided, good adhesion can be easily obtained with a weak force, and it can be easily attached to inorganic objects with irregular cross sections such as curved surfaces and uneven surfaces. Since there is a pressure-sensitive adhesive layer on the opposite side, this can be used to temporarily attach self-supporting materials, and even when using a thin glass powder sheet, it is easy to work and adhere The accuracy is very good. Furthermore, when bonding to an inorganic object, the thermal decomposition temperature of the pressure-sensitive adhesive layer on the side is set higher than the thermal decomposition temperature of the organic binder used in the glass powder sheet, which has the following advantages. That is, first, at the temperature at which the pressure-sensitive adhesive layer begins to thermally decompose, most of the organic binder in the glass powder sheet has already disappeared;
The glass powder sheet has air permeability.

Therefore, the decomposed gas generated by thermal decomposition of the pressure-sensitive adhesive layer can easily pass through the glass powder layer, so that the glass powder sheet does not become encapsulated and cause blisters during the firing process. As a result, the coating layer does not peel off. Second, at temperatures where the pressure-sensitive adhesive layer decomposes and loses adhesive strength, the glass powder sheet is powdered, so even if the organic binder remains in the glass powder sheet,
No displacement of the glass powder sheet layer due to curling up, shrinkage, etc. occurs.

(Example) EXAMPLES The present invention will be explained in more detail with reference to Examples below.

However, parts indicate parts by weight.

Example 1 As the glass powder, SiO□-CaO-BaO glass powder having a softening temperature of 850°C and a mesh size of 325 or less was used. butyl acrylate per 100 parts of glass powder,
Copolymer of methyl methacrylate and methacrylamide (6
0:35:5, thermal decomposition end temperature 560°C) 15 parts, sorbitan monooleate 1 part as a dispersant, toluene 2
After mixing and dispersing 4 parts of methyl ethyl ketone and 16 parts of methyl ethyl ketone at room temperature using a ball mill, a polyester film (thickness 5
0 μm) using a doctor blade to obtain a glass powder sheet with a thickness of 100 μm.

Next, an acrylic adhesive N containing polybutyl acrylate as a main component (thermal decomposition end temperature: 610° C.) was laminated to a thickness of 10 μm on the glass powder sheet, and this was attached to the surface. On the other hand, a rubber adhesive mainly composed of isoprene rubber (thermal decomposition end temperature: 390°C) is laminated on the back side to a thickness of 10 μm, and on this side, a release-treated polyethylene terephthalate (hereinafter abbreviated as PET) is laminated to a thickness of 50 μm. ) The film was temporarily attached as a support.

Next, it was attached to an alumina sintered body, which is an inorganic object, via an acrylic adhesive layer, which is a bonding surface. Pasting was successful.

Next, the PET film serving as the support was peeled off and exposed to air for 40 minutes.
After baking at 0°C for 60 minutes to remove the organic binder, the temperature was raised to 1300°C at a heating rate of 10°C/min, held at the same temperature for 120 minutes, and then cooled in a furnace.

The formed glass coating layer was in good condition with no displacement or peeling.

Example 2 As the glass powder, a NA20-Af□03.P2O type glass powder having a softening point of 450°C and a mesh of 325 or less was used. To 100 parts of glass powder, add 12 parts of polygotyl methacrylate (thermal decomposition end temperature: 350°C), 3 parts of dibutyl phthalate as a plasticizer, 1 part of sorbitan monooleate as a dispersant, 30 parts of toluene as a solvent, and 15 parts of methyl ethyl ketone at room temperature. After mixing and dispersing using a ball mill, it was cast onto a PET film (thickness 50μm) using a doctor blade to form a film with a thickness of 80μm.
A glass powder sheet of m was obtained.

Next, a rubber adhesive mainly composed of isoprene rubber (thermal decomposition end temperature: 390°C) was laminated to a thickness of 10 μm on both sides of the glass powder sheet, and one side was subjected to mold release treatment to a thickness of 100 μm. Temporarily attached using paper as a support.

Next, it was attached to a 5US304 board via a rubber adhesive layer that served as a bonding surface. Pasting was successful. Then, the paper support was peeled off and heated at 350°C in the atmosphere.
After baking for 60 minutes at 10°C to remove the organic binder.
The temperature was raised to 500°C at a heating rate of C/min, held for 10 minutes, and then cooled in the furnace. The formed glass coating layer was in good condition with no displacement or peeling.

[Brief explanation of the drawing]

Figure 1 is a reference diagram showing the operation of pasting the glass coating adhesive sheet of the present invention onto an inorganic object. Figure (c) shows the state in which the self-supporting material has been peeled off. 1...Glass powder sheet 2. 2'...Pressure sensitive adhesive layer 3...Self-supporting material (or more)

Claims (5)

[Claims] (1) An adhesive sheet for glass coating, characterized in that pressure-sensitive adhesive layers are provided on both sides of a glass powder sheet containing glass powder and an organic binder as main components. (2) The adhesive sheet for glass coating according to claim 1, wherein the pressure-sensitive adhesive layer provided on at least one surface of the glass powder sheet is thermally decomposed at a higher temperature than the organic binder. (3) The adhesive sheet for glass coating according to claim 1, wherein the glass powder sheet has a thickness of 10 to 200 μm. (4) The adhesive sheet for glass coating according to claim 1, wherein a self-supporting material is temporarily attached to one of the pressure-sensitive adhesive layers provided on both sides of the glass powder sheet. (5) A self-supporting material is temporarily attached to one side of the adhesive sheet for glass coating, which is made by providing a pressure-sensitive adhesive layer on both sides of a glass powder sheet mainly composed of glass powder and an organic binder, and the other side is A method of coating glass, characterized in that it is laminated under pressure onto an object to be coated via a pressure-sensitive adhesive layer, then the self-supporting material is peeled off and fired.