Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Noninterengaged fiber-containing paper-free web or sheet...
Reexamination Certificate
1999-11-18
2002-10-22
Weisberger, Rich (Department: 2164)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Noninterengaged fiber-containing paper-free web or sheet...
C428S297400, C428S297700, C428S298100, C428S220000, C428S423100, C052S385000, C349S073000
Reexamination Certificate
active
06468643
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laminated tile or laminated sheet which is obtained by using urethane-based resin, has excellent dimensional stability and application ability in site, and can be suitably used for indoor and outdoor flooring, wall covering and road paving.
BACKGROUND ART
Floor covering materials generally include wood-based, stone-based, fiber-based, resin-based and rubber-based materials and are selectively used depending upon property, function and use. Particularly, polyvinyl chloride resin is a representative resin-based flooring material, is inexpensive and has excellent ability in processing and design application. Thus, the resin becomes widespread use for residence flooring in the form of a cushion tile or design tile. The resin is also used for flooring of shops, public services and other broad range of uses. However, polyvinyl chloride resin contains a large amount of plasticizer when used for flooring, and thus, after application, leads to problems on inferior dimensional stability with time. That is, shrinkage due to decrease in plasticizer generates a gap in a corner portion or joint area. As an essential problem, polyvinyl chloride resin has a large linear expansion coefficient as compared with wood-based, stone-based and metal-based materials, and thus leads to large dimensional change under environment of great temperature variation. For example, when a polyvinyl chloride tile is directly heated, the tile greatly swells on account of a large coefficient of linear thermal expansion and causes knockout of the joint area or peeling of the tile. On the other hand, remarkably low temperature leads to tile shrinkage and develops a gap at the joint area. These problems are not limited to polyvinyl chloride resin. Any resin has the same essential problem to some extent.
Further, conventional tiles of polyvinyl chloride resin are mostly prepared by extrusion or rolling continuously in one axis. As a result, difference in dimensional change between the longitudinal and transverse directions due to the difference in density or residual stress is observed in a finished product. Consequently, in the step of applying tiles to the substrate, caution must be taken to the application direction so as to eliminate local deviation of dimensional change in the longitudinal and transverse directions. That is, extremely complicated laying operation is required.
On the other hand, urethane-based resin is excellent in impact resistance, abrasion resistance, thermal resistance, chemical resistance and waterproof property as compared with polyvinyl chloride resin, and is used for veranda, corridor, floor and roof of factories and public services and other objects where durability and waterproof property are required in particular. Thus, urethane-based resin has good result as a high functional flooring material. In the case of urethane-based resin, general application method to flooring is to coat or spray urethane raw materials on the substrate in the application site. These methods do not form joint area and thus can sufficiently exhibit essential waterproof property of urethane-based resin. Further, urethane raw materials before curing are liquid having relatively low viscosity, excellent in self-leveling property, and advantageous in increasing flatness after application even in the presence of surface irregularity of the substrate. However, the process for curing urethane raw materials in the application site requires a long coating time and prolonged curing period. And the spray coating method requires large sized equipment and considerable working space. Further, generation of urethane mist during course of spraying provides problems on workability. Prohibition of putting an article on the whole application area during curing is also a factor for the extending application period. When the substrate is smooth and inclined, it becomes difficult to coat with a constant thickness on the overall surface of application.
On the other hand, particularly quick curing type urethane are accompanied by considerable exothermic heat in the application period. Thus, after curing, volume shrinkage due to curing of urethane raw materials overlaps volume shrinkage accompanied by temperature reduction, and increases the possibility of warpage and peeling when adhesion to the substrate is weak. Even though adhesion of the substrate is sufficient and no peeling is observed in the application period, peeling force acts latently and thus peeling becomes possible, when markedly great external force is applied or when adhesive force is decreased after a long passage of time. Consequently, in a view point including the curing period, the operation of coating and curing urethane raw materials on the substrate in the application site remains strongly uncertain feeling for future dimensional stability and peeling. Further, cured urethane-based resin has also poor dimensional stability like polyvinyl chloride resin for large temperature variation, and thus generation of gap or knockout in a joint area is anticipated when used for a tile material. Though urethane-based resin can be greatly expected as a high-functional flooring material, improvement in dimensional stability and application ability has become a great problem to be solved.
Firstly, a process for improving application ability of urethane-based resin has been proposed in Japanese Laid-Open Patent HEI 9-131834. According to the process, urethane-based resin is cured before application and not during application. The resulting prefabricated tile-like material is put on a portion or the whole area of the substrate to be applied. The process can reduce the time for application. However, dimensional stability of the tile itself has not been improved because the tile is a laminated product consisting of urethane-based resin and uncured butyl rubber. On the other hand, a structure of inorganic long fiber reinforced waterproof layer using urethane-based resin as a waterproof layer has been disclosed in Japanese Laid-Open Patent HEI 9-300521. However, conventional process is used and urethane materials are coated in the application site. Thus, the application time cannot be reduced as mentioned above. Further, presence of the inorganic long fiber reinforced layer can supposedly maintain dimensional stability as overall laminated product. However, in view of including the cure time, volume shrinkage takes place as a result of curing of urethane raw materials as mentioned above, shrinking force generates in the urethane layer, and damage of warpage and peeling develops latently.
Therefore, the object of the invention is to overcome the above problems and to provide an urethane-based resin laminated product having excellent dimensional stability and application ability.
DISCLOSURE OF THE INVENTION
As a result of an intensive investigation on urethane-based resin materials having excellent dimensional stability and application ability in view of the above subject, the present inventors have found that a laminated product having excellent dimensional stability and application ability in site can be obtained by laminating urethane-based resin on a fiber-reinforced resin. Thus, the present invention has been completed.
That is, the aspect of the invention relates to the following (1)~(11).
(1) A laminated product characterized by laminating a urethane-based resin layer on a fiber-reinforced resin layer, consisting of two or more layers, and having a linear expansion coefficient of 2.0×10
−5
/° C. or less and thermal dimensional change of 0.1% or less in the dimensional stability for the two fiber directions, wherein the fiber-reinforced resin layer is obtained by laminating two or more prepreg sheets so as to intersect fiber directions at right angles or obtained by further laminating a non-woven fabric on one or both surface of the resulting laminated prepreg, and said prepreg sheet has a thickness of 50 to 1,000 &mgr;m and is obtained by arranging a continuous reinforcing fiber in one direction and impregnating the
Iiyama Takashi
Kanbayashi Takashi
Katayama Hiroyuki
Kawasumi Tamio
Burns Doane Swecker & Mathis L.L.P.
Mitsui Chemicals Inc.
Weisberger Rich
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