Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-04-19
2004-06-22
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S186000, C525S190000
Reexamination Certificate
active
06753379
ABSTRACT:
The present invention relates to thermally activated adhesive compositions that form adhesive films wherein the surface practically does not have adhesive properties and adhesive films made from said adhesive compositions.
Adhesives that have as their main component an adhesive polymer, also called pressure sensitive adhesive (adhesive agent), and it is a material where only by the application of pressure it is easily and strongly adhered. However, because of the fact that it has adhesive properties, the processing properties for punching processing etc., are poor and also the positioning is difficult.
Then, there have been numerous technologies for the control of the adhesive properties of the adhesive films (that have a binding layer that is formed from an adhesive agent). For example, there is the method where onto the adhesive surface, by using an embossing technological process indentations and protrusions are provided and the apparent adhesive properties are reduced, and then by heating these are smoothed out and flattened and by that the adhesive force is increased (disclosed according to the reported in the Japanese Patent Application Laid Open Number Hei-Sei 4-309583). Namely, it is a method where at the time of the processing and positioning, the state of protrusions and indentations of the adhesive surface, that has a low adhesive force relative to the material that is the subject of the adhesion, is maintained, and at the state where the adhesion is to be completed, the adhesive surface is smoothed out and flattened and the adhesive force is increased.
Also, as an adhesive film that has an adhesive layer containing a crystalline component, there is a material that has been disclosed according to the reported in PCT Publication WO 97/46633. By the adhesive layer of this adhesive film inside the adhesive polymer material a crystalline acrylate component is incorporated as a continuous phase. Also, by this adhesive layer, it is relatively difficult to lose the adhesive force and to completely lose the adhesive properties and usually, the binding surface (the adhesive surface) has adhesive properties. Consequently, properties of memory of its shape are generated and the adhesive surface that has protrusions and indentations as the secondary shape, is changed to the smooth adhesive surface which is the memory shape state (the primary state), and by that the same way as in the above described the easiness of the processing properties and the positioning properties, is increased.
However, in the case of such adhesive films, after the stage of the processing and the positioning (initial stages) it is not possible to form a smooth binding surface possessing film adhesive. In the case when the binding surface has adhesive properties and not only that but also it has a structure containing protrusions and indentations, the elimination of the impurities that are adhered at the time of the processing and positioning, is difficult. Also, in order to reliably sustain such binding surface with protrusions and indentations, it is necessary to have a specific liner (a material where the release surface also has a structure containing protrusions and indentations, etc.), and the economics are also complicated. Also, the Tg of the adhesive polymer material itself is relatively low, and the thermal resistance properties are also low.
On the other hand, adhesives are also known where adhesive properties are generated or increased by heating, and they are so-called thermally activated adhesive. In the case of the thermally activated adhesive, it is also called hot melt film adhesive, or heat sensitive type adhesive. Also, in order to increase its binding strength, the material is also known where an adhesive polymer material and a thermoplastic resin material are combined.
Regarding the thermoplastic resin materials that are used as thermally activated adhesive, there are many types, for example, it is possible to use polyester material. For example, in the reported in the description of the Japanese Patent Application Laid Open Number Showa 56-501131, thermally activated adhesive composition material with improved thermal resistance properties, has been disclosed. Namely, it is a adhesive composition material that contains (i) approximately 100 weight parts of a thermoplastic polymer material, (ii) a cross-adhesive (crosslinking agent), and (iii) approximately from 1 to 100 weight parts of an organic polymer material that has a complex number of functional radicals that can be used for the crosslinking reaction with the above described crosslinking agent. As the above described thermoplastic polymer material, it is possible to use polyester or polyurethane etc., and as the above described organic polymer material, it is possible to use polyalcohol type or polyamine type polymers, etc. Also, as the above described crosslinking agent, it is possible to use diisocyanate or polyisocyanates. In the case of such crosslinked thermally activated adhesive composition materials, it is possible to efficiently increase the thermal resistance properties. Also, in the case of such thermally activated adhesives, usually, they do not have adhesive properties at room temperature, and because of that it is also possible: to increase the ease of processing and positioning properties. However, in this disclosed adhesive composition material, an adhesive polymer is not contained and because of that it is difficult to increase the binding strength.
On the other hand, in the description reported according to the Japanese Patent Application Laid Open Number Hei-Sei 8-134428, a hot melt adhesive composition material is disclosed that contains a thermoplastic adhesive, and an adhesive polymer. In this patent report, as the thermoplastic adhesive polyester, and as the adhesive polymer material isooctyl acrylate—acrylic acid type copolymer material, are correspondingly given as the examples. In the case of this composition material also it is necessary that there is a phase separation of the adhesive polymer material and the thermoplastic adhesive. The reason for that is so that the coating properties of the hot melt adhesive agent at the time when it is coated in a liquid state, are increased, and also, so that the adhesive properties are maintained for a relatively long period of time (even when after cooling it is apparently solidified) after the coating technological process. Namely, in the case of this composition material, it is a material that is more appropriate to be used as a adhesive of the type that is liquefied and then used, than the material used as a film adhesive, where by heating the adhesive properties of the binding surface are increased.
In the descriptions reported according to the Japanese Patent Application Laid Open Number Hei-Sei 6-256746, Japanese Patent Application Laid Open Number Hei-Sei 5-339556, a thermally activated film adhesive has been disclosed that is formed from a composition material, where as the thermoplastic resin material a phenoxy resin, and then an epoxy resin, and their crosslinking agents are contained. In the case of the above described adhesive acrylic type polymer material, it is preferred that it is a material that contains in its molecule a carboxyl radical, a hydroxyl radical, or an epoxy radical.
Usually, the adhesives in the form of films that are usable in electrical type applications, are used so that after the punching, they are positioned and the electronic part etc., is bonded, and because of that it is good if the adhesive properties (the adhesive properties at room temperature, at approximately 25° C.) are as low as possible, and the materials that practically do not have adhesive properties are especially appropriate. Also, regarding the adhesives for electrical applications, there are many cases where thermal resistance properties are required and because of that usually, the pressure sensitive adhesive agents are not appropriate for these types of applications.
On the other hand, in the case of the combination of the usual adhesive polymer material
Kawate Kohichiro
Muramatsu Akito
Takamatsu Yorinobo
Yamaguchi Hitoshi
Bardell Scott A.
Short Patricia A.
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