Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2000-09-25
2003-04-15
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S323000, C428S500000, C428S522000
Reexamination Certificate
active
06548150
ABSTRACT:
TECHNICAL FIELD
The present invention relates to recording media, and in particular, relates to recording media for ink jet printers, in which ink absorptivity is superior, surface strength is superior, there is no decrease in density and no changing in color tone in direct sunlight or in room light, and in which ink is quickly absorbed, thereby satisfying future high speed printing technique requirements.
BACKGROUND ART
The use of ink jet printers is further increasing in recent years because they have characteristics such as vividness of recorded images, quiet operation, ease of coloring, and the like. In order to prevent the nozzle from being blocked due to drying of ink, an ink which is difficult to dry must be used in the ink jet printer. As ink having this property, water-soluble ink which is dissolved or dispersed with dye, solvent, additives, or the like, in water, is generally employed. However, a letter or an image formed on the recording medium by using the water-soluble ink is more inferior to that in printed matter using pigment-type inks or to that in silver halide photographs from the viewpoint of water resistance, moisture resistance (having no color changing or fading even if the medium is left under high temperature and high humidity), and light resistance such as shelf-life in a room and resistance to direct sunlight.
In recent years, as ink jet printers become less expensive and high vividness and colorfulness of printed image is anticipated, the requirements for various properties such as light resistance of recorded images, surface strength of recording media for ink jet printers, etc., are gradually becoming severe. Therefore, completely satisfying these various requirements, such as light resistance, surface strength, etc., is an essential goal for recording media for ink jet printers.
In conventional recording media for ink jet printers, improvements in light resistance of recordings of letters, images, etc., in particular, full color recordings, have been proposed; however, they are not yet sufficient. Furthermore, in the recording media for ink jet printers, an ink receiving layer containing many pigment components having superior ink absorbability is formed, and a large amount of ink is used in full color recordings. Surface strength of the ink receiving layer is thereby deteriorated, so that there are problems with respect to surface strength, such as flaking off of the pigment, or peeling of the ink receiving layer, when the media are rubbed on the surface or are bent.
DISCLOSURE OF INVENTION
Therefore, the present invention has been made in view of the above circumstances, and it is an object thereof to provide a recording medium for ink jet printers having superior recording properties for ink jet printers, and having superior light resistance, which did not exist in the past, and having superior surface strength so that recorded images are not easily peeled off.
The inventors have conducted various research with regard to recording media for ink jet printers, and have found that the light resistance and the surface strength of the recording media for ink jet printers are improved very effectively by providing an ink receiving layer containing an acrylic type copolymer in which (metha)acrylate, hydroxyalkyl (metha)acrylate, and antioxidation monomers and/or ultraviolet ray absorption monomers are copolymerizing components.
Therefore, a recording medium for ink jet printers according to the present invention has been made on the basis of the above knowledge, and it is characterized in that an ink receiving layer is provided on a base material, the ink receiving layer contains an acrylic type copolymer in which at least three components, an A component: (metha)acrylate, a B component: hydroxyalkyl (metha)acrylate, and a C component: antioxidation monomer and/or ultraviolet ray absorption monomer are copolymerizing components.
A recording medium for ink jet printers according to the present invention has a structure in which at least one ink receiving layer is laminated on at least one surface of a base material by a laminating method such as a coating method, and the ink receiving layer may consist of two or more layers. If it consists of two or more layers, the acrylic type copolymer of the present invention may be contained in at least either of the layers.
A preferable embodiment according to the present invention has a structure in which two or more ink receiving layers are laminated. A first embodiment is characterized in that the acrylic type copolymer of the present invention is contained in a first ink receiving layer being on a base material side and a second embodiment is characterized in that it is contained in a second ink receiving layer being on a surface side, and these will be explained in detail. The above first ink receiving layer and second ink receiving layer may consist of two or more layers, respectively.
In the first embodiment, the A component: (metha)acrylate is preferably alkyl acrylate, and in the second embodiment, it is preferably dialkylamino alkyl methacrylate. Furthermore, in the second embodiment, not only the above A, B, and C components, but also acrylamide, must be contained as an essential copolymerizing component of the acrylic type copolymer.
1. First Embodiment
(1) Base Material
As a base material provided for an ink receiving layer according to the present invention, a base paper which is mixed wood pulp, such as a chemical pulp such as LBKP, NBKP, or the like; mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP, CGP, or the like; recycled pulp such as DIP, or the like; etc.; or synthetic fiber pulp such as polyethylene fiber, or the like, as a primary component, with pigment and any type of additive which is typically employed in paper, such as sizing agents, yield improving agents, strengthening agents, or the like, alone or in combination, as necessary, and produced by using any type of paper-making apparatus such as a fourdrinier paper machine, cylinder paper machine, twin wire paper machine, or the like; can be preferably employed. In addition, a base paper provided with starch, polyvinyl alcohol, or the like using a size press; a base paper provided with an anchor coat layer; a coated paper such as art paper, coated paper, cast coat paper, or the like, which is provided with a coat layer on these base papers, can preferably be employed. These base papers and coated papers may be provided with an ink receiving layer directly, and a paper controlled flattening before coating the ink receiving layer, using a calender apparatus such as a machine calender, TG calender, soft calender, or the like, may be employed.
As a base material, a polyolefin resin layer may be provided on the surface of the above-described base paper, and synthetic resin such as polyethylene, polypropylene, polyester, nylon, rayon, polyurethane, or the like; film material comprised of mixture with these; and fiber-formed media of these synthetic resins may be employed.
(2) First Ink Receiving Layer
In this embodiment, as a main component of the binder resin in the first ink receiving layer provided on the base material, acrylic type copolymer in which at least three components consisting of the A component: alkyl acrylate, the B component: hydroxyalkyl (metha)acrylate, and the C component: antioxidation monomer and/or ultraviolet ray absorption monomer are copolymerizing components, is employed. Superior recording properties for ink jet printers can thereby be attained. The first ink receiving layer is formed by adding other binder resins or additives to this acrylic type copolymer and pigment as necessary.
(a) Copolymerizing Component of Acrylic Type Copolymer
Alkyl acrylate of the above A component has effects on film strength, miscibility with pigments, stability of the coating material, etc., and as alkyl acrylate, a chemical compound shown in the following chemical formula 1 can be employed. The content of alkyl acrylate in the acrylic type copolymer is preferably 50 mole % or more. If it is less than 50 mole %, the film strengt
Ishikawa Takayuki
Ishikawa Yukari
Iwamoto Kiyoshi
Kobayashi Shin-ichiro
Kubota Nobuhiro
Kelly Cynthia H.
Scully Scott Murphy & Presser
Seiko Epson Corporation
Shewareged B.
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