Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Physical dimension specified
Reexamination Certificate
2001-09-25
2004-09-14
Zacharia, Ramsey (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Physical dimension specified
C428S411100, C428S913300, C428S914000
Reexamination Certificate
active
06790525
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to decorative materials to be used for building interior materials such as walls, surface materials of furniture and fixture such as doors and vehicle interior materials, and particularly, to decorative materials which show excellent abrasion resistance because of their structure having a surface protective layer comprising a crosslinked resin.
Heretofore, decorative materials, such as decorative sheets, for applications such as those described above are usually required to have abrasion resistance. Thus, decorative materials whose surface protective layers are formed from two-component curing urethane resin paints, ionizing-radiation-curing resin paints and the like are practically used today.
(1) For example, JP-B 49-31033 and JP-B 4-22694 disclose a decorative material wherein a pattern layer is formed on a substrate by printing and then a surface protective layer is further formed, the surface protective layer comprising a resin resulting from a procedure comprising applying an ionizing-radiation-curing resin paint of unsaturated polyester type, acrylate type or the like to form a coating film, and then curing the film by crosslinking with electron beams.
(2) Furthermore, for the case where a greater abrasion resistance is required, the published specification of Japanese Patent No. 2740943 discloses the addition of spherical particles such as spherical &agr;-alumina as an abrasion reducing agent to an ionizing-radiation-curing resin forming a surface protective layer.
However, even though a surface protective layer is formed of a crosslinked resin like in the above (1), abrasion resistance can not be improved beyond a certain limit and only insufficient abrasion resistance may be obtained. The addition of hard inorganic particles as an abrasion reducing agent to the resin of a surface protective layer like in the above (2) can improve abrasion resistance, but it may cause a problem of generating a rough feeling in the surface of the surface protective layer. Moreover, in the approach of the above (2), a problem, which is caused by the addition of the abrasion reducing agent, that a plate, a doctor blade and the like become easy to be worn during the formation of a surface protective layer is solved by the use of spherical particles as an abrasion reducing agent. The use of such a specific abrasion agent, however, may also cause a high cost problem.
SUMMARY OF THE INVENTION
The problem to be solved by the present invention is to provide to a decorative material with excellent abrasion resistance.
In order to solve the above problem, the decorative material of the present invention has a structure, that is, a decorative material comprising an intermediate resin layer and a surface protective layer including a crosslinked resin, the layers being laminated in this order on a substrate, wherein a temperature dependency characteristic at a measuring frequency of 10 Hz of loss elastic modulus determined by a dynamic viscoelasticity method of the intermediate resin layer has a peak at least at a temperature lower than room temperature.
If, as described above, an intermediate resin layer whose dynamic viscoelastic characteristic is specified to have a peak of loss elastic modulus in the region under room temperature is provided, an excellent abrasion resistance can be achieved without adding any abrasion reducing agent such as inorganic particles to a surface protective layer. This is probably because the intermediate resin layer which became moderately soft at room temperature where an abrasion stress is added serves as a cushion. In other words, it is probable that when an adequate elastic restoring force is applied and simultaneously an external force (abrasion stress) that wears a surface is applied to a surface protective layer, an intermediate layer underlying the surface protective layer absorbs and relieves the external stress by dispersing the external stress to a large area (volume) to reduce it and further converting it to heat to dissipate, and as a result, the surface protective layer becomes difficult to be worn and its abrasion resistance is improved. For this reason, the necessity of adding abrasion reducing agents such as inorganic particles to the surface protective layer may be eliminated depending upon the degree of abrasion resistance required and it will become possible to avoid a rough feeling of a surface and abrasion of plates occurring during the formation of a surface protective layer, which would occur when abrasion reducing agents were added.
Moreover, the decorative material of the present invention may further have a structure where the value of storage elastic modulus determined by a dynamic viscoelasticity method of the intermediate resin layer is 1×10
7
to 2×10
9
Pa in the range of room temperature, based on the above-mentioned structure.
By adopting the structure of specifying the dynamic viscoelastic characteristics also about the storage elastic modulus, excellent abrasion resistance can be obtained more certainly without adding any abrasion reducing agent such as inorganic particles to the surface protective layer. This is probably because an intermediate layer can be provided with such a moderate elastic restoring force that a surface protective layer is prevented from excessive deformation and a surface layer is allowed to recover from its deformation and the surface hardness of the surface protective layer is maintained.
Moreover, the decorative material of the present invention may further have a structure where the temperature dependency characteristic at a measuring frequency of 10 Hz of loss elastic modulus determined by the dynamic viscoelasticity method of the intermediate resin layer further has a peak at a temperature higher than room temperature.
By adopting the structure of specifying to have a peak of loss elastic modulus also in the temperature region higher than that where decorative materials are practically used, excellent abrasion resistance can be obtained more certainly without adding any abrasion reducing agent such as inorganic particles to the surface protective layer. This is probably because the peaks of the temperature dependency characteristic of loss elastic modulus appearing, respectively, at a temperature under room temperature and at a temperature over room temperature make storage elastic modulus at room temperature easy to fall within a moderate region, thereby providing to the intermediate resin layer such a moderate elastic restoring force that the surface protective layer is prevented from excessive deformation and a surface layer is allowed to recover from its deformation and the surface hardness of the surface protective layer is maintained.
According to the decorative material of the present invention, an excellent abrasion resistance can be obtained due to the intermediate resin layer having a specific dynamic viscoelastic characteristic of having a peak of loss elastic modulus under room temperature. For this reason, for some abrasion resistance required, it is not necessary to add abrasion reducing agents such as inorganic particles into a surface protective layer. For this reason, the necessity of adding abrasion reducing agents such as inorganic particles to the surface protective layer may be eliminated depending upon the degree of abrasion resistance required and it will become possible to avoid a rough feeling of a surface and abrasion of plates at the formation of the surface protective layer, which would occur when abrasion reducing agents were added.
Furthermore, by specifying the dynamic viscoelastic characteristic of the intermediate resin layer to a specific storage elastic modulus, adequate elastic restoring force required for improving abrasion resistance and for maintaining surface hardness is obtained and therefore the above-mentioned effect (1) can be obtained more certainly.
In addition to the above (1) or (2), it becomes easy to obtain adequate elasticity restoring force required for improving abrasion resistanc
Endo Keisuke
Kitagawa Shoichi
Takeuchi Hajime
Dai Nippon Printing Co. Ltd.
Ladas & Parry
Zacharia Ramsey
LandOfFree
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