Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2002-01-16
2003-10-28
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S354000, C428S344000, C428S915000, C428S916000, C428S913000, C428S042100, C428S041700, C428S688000, C428S323000, C428S142000, C428S143000, C106S287350
Reexamination Certificate
active
06638606
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a hardcoat for a highly transparent plastic substrate, having good suitability for printing. More particularly, the present invention relates to a hardcoat which has a surface capable of realizing high-speed printing and, in addition, possessing excellent scratch resistance and, at the same time, possesses excellent crack preventive properties, adhesion, and capability of preventing influence of, for example, the deformation of a plastic substrate from extending to the hardcoat, a hardcoat for holograms, a hardcoat film, an antireflection film, and a production process thereof.
The present invention further relates to a hardcoat provided on a highly transparent plastic substrate film, a hardcoat film, and a production process thereof, and more particularly to a hardcoat possessing excellent scratch resistance and, at the same time, excellent crack preventive properties, adhesion, and capability of preventing influence of, for example, the deformation of a plastic substrate from extending to the hardcoat, a hardcoat film, and a production process thereof. The present invention further relates to an antireflection film comprising an antireflection layer provided on the hardcoat. The present invention further relates to a heat reflecting film comprising a heat reflecting layer provided on the hardcoat. The present invention further relates to an ultraviolet shielding film comprising an ultraviolet shielding layer provided on the hardcoat.
BACKGROUND OF THE INVENTION
In recent years, plastic products are being substituted for glass products from the viewpoints of moldability and a reduction in weight. Since, however, the surface of the plastic products is likely to be scratched, a hardcoat film is in many cases applied to the plastic products to impart scratch resistance. Also in the case of the conventional glass products, there is a growing tendency for a plastic film to be applied thereto to prevent scattering. Due to unsatisfactory hardness of the plastic films, however, a hardcoat is in most cases formed on the surface of the plastic films.
The conventional hardcoat film has been produced by coating the surface of a plastic substrate film with a highly scratch-resistant resin, generally a thermosetting resin or an ionizing radiation curing resin, such as an ultraviolet curing resin, either directly or through an about 1 &mgr;m-thick primer layer to a small thickness of about 3 to 15 &mgr;m (for example, Japanese Patent Laid-Open No. 151914/1995).
Further, in the conventional hardcoat films, an attempt has been made to add an inorganic filler to a film-forming organic component having a polymerizable functional group to enhance the hardness (for example, Japanese Patent Laid-Open No. 41362/1990).
The conventional hardcoats, however, have a small coating thickness and, hence, hardcoat is directly influenced by the deformation of the plastic substrate film underlying the hardcoat. That is, the surface strength is low and unsatisfactory.
On the other hand, merely increasing the thickness of the hardcoat to a larger value than the conventional thickness, that is, more than 3 to 15 &mgr;m, can improve the surface hardness of the hardcoat film, but on the other hand, cracking or peeling is likely to occur and, at the same time, curling derived from cure shrinkage is increased. Therefore, the hardcoat film cannot be put to practical use.
In the conventional hardcoat films, incorporation of the inorganic filler into the organic component having a polymerizable functional group can provide a film having improved surface hardness. In this case, however, cracking and peeling are likely to occur and, at the same time, curling derived from cure shrinkage is increased. This renders the hardcoat film unsatisfactory for practical use.
When the hardcoats are used as protective films for preventing specific products from being scratched, production numbers, dates and the like associated with the product are printed on the hardcoats. In this case, for hardcoats to which scratch resistance has been imparted, for example, by forming a dense film as the surface layer or by imparting slipperiness to the surface, a printing ink is less likely to be penetrated thereinto or a dye for sublimation transfer is less likely to be fixed. This results in poor productivity.
When a tacky layer is present on the backside of the plastic substrate film, the formation of a hardcoat on the other side of the substrate film followed by superposition or winding of the assemblies poses a problem that the tacky layer is transferred to the hardcoat.
When the hardcoats are used as protective films for preventing specific products from being scratched, production numbers, dates and the like associated with the product are printed on the hardcoats. In this case, for hardcoats to which scratch resistance has been imparted, for example, by forming a dense film as the surface layer or by imparting slipperiness to the surface, a printing ink is less likely to be penetrated thereinto or a dye for sublimation transfer is less likely to be fixed. This results in poor productivity.
DISCLOSURE OF THE INVENTION
First Invention
Accordingly, it is an object of the first invention to solve the above problems involved in hardcoat films using a plastic substrate and to provide a hardcoat for a plastic substrate, a hardcoat for a hologram, a hardcoat film comprising the hardcoat applied to a plastic substrate, an antireflection film comprising an antireflection layer applied onto the hardcoat, and a process for forming a hardcoat which can realize satisfactory hardness properties while enjoying good suitability for printing even in the case of a small coating thickness, can prevent the influence of the deformation of the plastic substrate on the hardcoat, can prevent cracking and peeling of the hardcoat, can bring the pencil hardness of the surface of the hardcoat film to H to 5H, and, further, even when a tacky layer is present on the backside of the plastic substrate with a hardcoat formed on the front side thereof, can prevent the transfer of the backside layer onto the hardcoat. Thus, according to the first invention, there is provided a hardcoat for a plastic substrate, characterized by being produced from a coating component containing one or more organic components having a polymerizable functional group and an inorganic filler, at least one of the organic components being free from a hydrogen bond-forming group.
Further, according to the present invention, there is provided a process for producing a hardcoat for a plastic substrate, characterized by comprising the steps of: coating the surface of a plastic substrate with a coating liquid comprising one or more organic components having a polymerizable functional group and an inorganic filler, at least one of the organic components being free from any hydrogen bond-forming group; drying the coating to remove the solvent in the coating; aging the dried coating at a temperature of 20 to 100° C. for 5 sec to 5 min; and then curing the coating.
In the hardcoat film of the present invention comprising a hardcoat applied onto a plastic substrate film, hardness properties have been imparted, for example, by coating the hardcoat either directly or through other layer onto at least one side of the plastic substrate.
According to the hardcoat for a plastic substrate film of the present invention, the content of the inorganic filler in the surface of the hardcoat is larger than that in the interior of the hardcoat, and the surface of the hardcoat has irregularities. This increases the surface area, or a porous structure is present in a very small region. Therefore, the suitability for printing can be enhanced, and the hardcoat is highly non-tacky.
According to the hardcoat for a plastic substrate film of the present invention, reticular connection of at least a part of the inorganic filler is preferred from the viewpoints of preventing cracking and peeling of the hardcoat, preventing curling of the hardcoat film per se, and, at the same time, en
Hojo Mikiko
Kunimine Noboru
Ota Yurie
Shioda Satoshi
Takahashi Nobuko
Boss Wendy
Dai Nippon Printing Co. Ltd.
Jones Deborah
Parkhurst & Wendel L.L.P.
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