Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-05-26
2002-07-16
Eashoo, Mark (Department: 1732)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S244240, C156S244210, C264S171100, C264S173190, C264S210100
Reexamination Certificate
active
06419778
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a covering sheet which can give matt feeling and, furthermore, preferred soft touch feeling, to a portion where people may touch, e.g., interior of automobiles, architectural interiors, housings of office automation equipment, household electrical goods, etc., stationery, sanitary goods, and is daily necessities; and to a method of producing the sheet and a molding using the sheet.
BACKGROUND ART
In order to provide surfaces of plastic moldings or metallic moldings with matt feeling (for example, suede-like soothing external appearance), suede-like covering coats are formed using paints or a shoot for moldings obtained by using paints.
For example, a suede-like shoot for molding is proposed in Japanese Laid-Open Patent Publication No. 2-41243 which is obtained as follows. The matt point which includes a bead pigment and an ionizing radiation curable resin vehicle is coated onto a base film having good moldability and cured.
However, since it is necessary to cure the ionized radiation curable resin composition by irradiation with an electron beam, etc. after the application thereof on a film, production steps for the sheet become complicated and the productivity is not satisfactory. Moreover, since a coating film of the sheet is made of a resin which is crosslinked using an electron beam, etc., the extensibility of the entire sheet is poor.
Japanese Laid-Open Patent Publication No. 59-202830 proposes an apparatus in which a molding is decorated while being engaged in injection molding using the sheet.
When the sheet disclosed in above-mention Japanese Laid-Open Patent Publication No. 2-41243 and the apparatus proposed in Japanese Laid-Open Patent Publication No. 59-202830 area incorporated in an attempt to obtain a molding having a soft touch feeling on the surface, the following problem arises.
When attempts are made to adhere the sheet onto the surface of the molding having unevenness or curves, there is a risk of the sheet being cracked since the extensibility of the shoot in poor. In particular, it is difficult to easily give matt feeling and soft touch feeling to the molding in deep draw forming.
Furthermore, Japanese Laid-Open Patent Publication No. 62-251111 proposes a method of producing a molding, comprising the steps of: previously placing a thermoplastic resin sheet in a mold; introducing a resin in the mold; and pressing the resin in the mold with a cope, thereby obtaining a molding having the thermoplastic resin sheet (decorating sheet) adhered to the surface thereof.
However, the molding obtained by the method proposed in Japanese Lain-Open Patent Publication No. 62-251111 does not produce matt feeling since its surface layer is formed only of the thermoplastic resin and minute unevenness is not formed on the surface. Also, touch feeling is rather stiff. Therefore, this production method cannot be used to produce products which require matt feeling or soft touch feeling to the human skin, e.g. interior of automobiles, housings, cases, etc.
DISCLOSURE OF THE INVENTION
The present invention overcomes the above-mentioned problems, and has the features of providing a covering sheet which has matt condition on its exterior and, furthermore, which has a soft touch feeling; a method of producing the same with good productivity without creating problems associated with conventional painting space or environmental problems associated with using solvents; and a method of producing a molding using the covering sheet.
Another feature of the present invention is to provide a method which can produce the above-mentioned covering sheet at relatively low cost.
A covering sheet of the present invention is made of a composition containing urethane type thermoplastic elastomer and elastic fine particles as main components.
A surface layer having minute unevenness on the surface thereof, an adhesive layer, and a substrate layer comprising an olefin type thermoplastic elastomer are laminated in this order to form the covering sheet.
In a method of producing the covering sheet of the present invention, the composition containing the thermoplastic elastomer and the elastic fine particles as main components is extruded, and then expanded, thereby obtaining the covering sheet having minute unevenness on the surface.
Since the covering sheet obtained in the method of the present invention is formed of the composition containing the-thermoplastic elastomer and the elastic fine particles as main components, and since the covering sheet has the surface layer having minute unevenness on the surface; matt feeling on the appearance, and generally, soft touch feeling can be given to a surface of a molding.
According to the method of producing the covering sheet of the present invention, minute unevenness is formed on the surface by extruding the composition containing the thermoplastic elastomer and the elastic fine particles as main components into a sheet-like shape, and then by expanding it. Therefore, it is not necessary to use a solvent and the sheet can be produced in good working environment. Moreover, since the sheet may be produced in a co-extruding method in a case where the covering sheet has a substrate layer, it is possible to perform continuous production in a single stop unlike the case where a paint is applied after the production of the substrate layer. Minute unevenness refers to the presence of bumps or waviness on the surface.
Therefore, a covering sheet which has matt feeling on its appearance, and generally, a soft touch feeling can easily be produced with considerably good productivity without creating conventional problems associated with a paint space or an environmental problem associated with using solvents, and the like.
Thermoplastic Elastomer
The thermoplastic elastomer for use in the present invention refers to a polymeric material which exhibits what is called rubber elasticity at room temperature and is capable of being plasticized into a variety of moldings at high temperature.
Examples of the above-mentioned thermoplastic elastomer include polyurethane type, polystyrene type, polyolefin type, polyester type, polyvinyl chloride type, polyamide type, ionomer type, fluororubber, 1,2-polybutadiene type, trans 1,4-polyisoprene type, synthetic natural rubber type, etc., which can be used either alone or in combination.
It is often the case that thermoplastic elastomer generally includes within a molecule both a rubber component (soft segment) having entropy elasticity and a molecular binding component (hard segment) preventing plastic deformation, and it sometimes includes a partial crosslinkage structure in a moldable range. However, it does not include an extensive, 3-dimensional network crosslinkage structure.
Hardness of the thermoplastic elastomer is preferably in the range of 20 to 98 in A hardness of JIS K6301, although it differs depending on the degree of touch feeling desired and the hardness of elastic fine particles (elastic beads are often used) to be used.
Specific examples of the above-mentioned thermoplastic elastomer of polyurethane type include block copolymer having polyurethane as hard segment, and polyether, polyester, polycarbonate, etc. as soft segmnent.
Specific examples of polystyrene type include block copolymer which has polystyrene as hard segment, and which has polybutadiene, polyisoprene, polyethylene-polybutylene as soft segment (referred to as SBS, SIS, SEBS block copolymers, respectively); and a block copolymer in which said block copolymer is further hydrogenated or supplemented with additional functional groups.
Specific examples of polyolefin type include
those which have polyolefin such as polypropylene as a hard segment, and which have ethylene as a soft segment (referred to as EPM (ethylene-propylene-methylene bonding)); those which have a polyolefin such as polypropylene as a hard segment, and which have a small amount of diene component together with ethylene as a soft segment (referred to as EPDM (ethylene-propylene-dienemethylene bonding), EPM and EPDM together being called EP
Miyake Akitaka
Tsuji Toshimitsu
Uematsu Tomoko
Eashoo Mark
Kinney & Lange , P.A.
Sekisui Kagaku Kogyo Kabushiki Kaisha
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