Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Composite having voids in a component
Reexamination Certificate
1998-12-15
2002-01-08
Copenheaver, Blaine (Department: 1771)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Composite having voids in a component
C428S317300, C428S3550AC
Reexamination Certificate
active
06337128
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a pressure-sensitive adhesion sheet for a silicone oxide-containing material, wherein an inorganic material comprising SiO
2
such as glass or tile is used as an adherend.
BACKGROUND OF THE INVENTION
In order to simplify workability or to improve safety and sanitation, an adhesion treatment using a pressure-sensitive adhesion tape instead of a conventional liquid adhesive is gradually currently used. With expanding the use of the pressure-sensitive adhesion tape, demanded properties are becoming hard. Of these demanded properties, as a practical property, moisture and heat resistance can be mentioned. In any use for household appliances, office appliances and automobiles, influences from temperature or humidity cannot be avoided. In particular, in such a circumstance as a surrounding of a bath, an influence from humidity is stronger than from temperature. However, conventionally currently used acrylic pressure-sensitive adhesives do not have sufficient moisture and resistance to an inorganic material mainly comprising SiO
2
such as glass or tile so that the adhesives lose their adhesion under high temperature and high humidity conditions, which may result in the detachment of a fixed member.
For the purpose of improving adhesion to glass, a method wherein a glass surface has been preliminary subjected to a silane-coupling treatment is commonly used. Further, is also disclosed a method wherein a silane-coupling agent is blended with an acrylic pressure-sensitive adhesive (refer to JP-B-62-30233) (The term “JP-B” as used herein means an “examined Japanese patent publication”). However, the former method requires a drying treatment at a high temperature and costly facilities, and also takes time. Further, the method is difficult to be applied to constructed glass windows. The latter method has severe restrictions in storage humidity conditions and storage term because of a short pot life of an alkoxysilane in a silane coupling agent. Thus, both methods are lacking of practical utility.
Further, in the pressure-sensitive adhesive tape, in order to reduce or disperse external force or vibration exerted on a member fixed by adhesion, or for improving follow-up property of the tape to the rough surface of the member, it has been well-known to use a foamed base material such as urethane, polyethylene or acrylfoam. Also in such a kind of double side pressure-sensitive adhesion sheet, if it is subjected to a circumstance of high temperature and high humidity, moisture permeates into a foamed base material and the permeated water penetrates into a glass interface from the back side of the pressure-sensitive adhesive layer so that the decrease in adhesion may occur. Even if a pressure-sensitive adhesive having an improved moisture resistance, the penetration of water from a foamed base material cannot be prevented so that the decrease in adhesion occurs as well.
It can be currently seen that a film or a label having a pressure-resistant adhesive layer is adhered to a glass plate or a container. For example, for imparting a design property to a window glass of a store, a print film having a pressure-sensitive adhesive layer is adhered. Further, a film for reflection prevention/light-screening or a film for preventing glass from scattering, each having a pressure-sensitive adhesive layer, is adhered to a window glass of a building. Still further, a reflection prevention film is adhered to a picture ray tube of a television installed outdoors or to a glass panel of a liquid crystal panel plasma display.
A pressure-sensitive adhesive used in these films is required to have excellent weather resistance and heat resistance. Further, since it is often subjected to rain or moisture condensation, it is also required to have water resistance and moisture resistance. Still further, in addition to the above-described films to be adhered to a window glass, for imparting a design property to a plain tile in a bathroom, a print film having a pressure-sensitive adhesive layer sometimes required to be adhered. Such kind of film, however, is to be subjected to a hot water and a high humidity, a pressure-sensitive adhesive having excellent moisture and heat resistance is required.
As a pressure-sensitive adhesive for these various kinds of films, acrylic pressure-sensitive adhesives having excellent weather resistance and heat resistance have been conventionally used. However, acrylic pressure-sensitive adhesives do not have sufficient moisture and heat resistance with respect to inorganic materials comprising SiO
2
as main components such as glass and tile. Therefore, when it is subjected to moisture and heat after being adhered to a film, such problemsmayoccur that the film is floated to form creases or to cause peeling.
In order to improve adhesion to a glass, has been currently used a method wherein the glass surface is previously subjected to a silane-coupling treatment. A method wherein a silane coupling agent is blended in an acrylic pressure-sensitive adhesive (JP-B-62-30233) was also disclosed. However, the former method requires a drying treatment at a high temperature and costly facilities, and also takes time. Further, the method is difficult to be applied to already constructed glass windows. The latter method has severe restrictions in storage humidity conditions and storage term because of a short pot life of an alkoxysilane in a silane coupling agent. Thus, both methods are lacking of practical utility.
As described in the above, in the prior art, have not been known practical pressure-sensitive adhesion sheets having excellent moisture and heat resistance for inorganic materials such as glass and tile. A foamed base material was used particularly for reducing or dispersing external force or vibration, or for improving follow-up property to the rough surface of a member. Those having excellent above-described properties can be scarcely found.
Thus, in the prior art, a practical film having a pressure-sensitive adhesive layer excellent in moisture and heat resistance for inorganic materials such as glass and tile has been scarcely known.
SUMMARY OF THE INVENTION
Under the above-described circumstances, an object of the present invention is to provide practical pressure-sensitive adhesion sheets having a high adhesion to inorganic materials such as glass and tile without using a silane coupling agent, and particularly those having excellent moisture and heat resistance, i.e., a high adhesion even under high temperature and high humidity conditions.
The object can be achieved by a first pressure-sensitive adhesion sheet for a silicone oxide-containing material, which comprises a foamed base material having formed on at least one surface thereof a layer composed of an acrylic pressure-sensitive adhesive comprising a copolymer comprising:
a) 60 to 94% by weight of an acrylic monomer represented by formula (1): CH
2
=C(R
1
)COOR wherein R
1
is a hydrogen atom or a methyl group; and R
2
is an alkyl group having 4 to 14 carbon atoms,
b) 5 to 40% weight of a (meth)acrylamide represented by formula (2): CH
2
=C(R
3
)CONR
4
R
5
wherein R
3
is a hydrogen atom or a methyl group; R
4
is a hydrogen atom or an alkyl group; and R
5
is an alkyl group or an organic group which is bonded to R
4
to form a hetero ring together with a N atom, and
c) 1 to 10% by weight of a monomer having an acidic group, each based on the total content of components a), b) and c),
wherein the foamed base material has a water absorption rate less than 15%, by weight after having been immersed in warm water having a temperature of 40° C. for 24 hours.
Furthermore, the object can be achieved by a second pressure-sensitive adhesion sheet for a silicone oxide-containing material, which comprises a plastic film formed on at least one surface thereof a layer composed of an acrylic pressure-sensitive adhesive comprising a copolymer comprising:
a) 60 to 95% by weight of an acrylic monomer represented by formula (1): CH
2
=C(R
1
)COOR
3
wherein R
1
is
Kitamura Yoshinao
Oji Katsunari
Yoshikawa Takao
Copenheaver Blaine
Nitto Denko Corporation
Roché Leanna
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