Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2001-05-31
2003-09-02
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S323000, C428S328000, C428S331000
Reexamination Certificate
active
06613418
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet recording material for a backlit use, particularly as a medical use, to an ink-jet recording material for a backlit use which is excellent in ink-absorption property and transparency, having a sufficient transmittance even in a use of back-lighting system in which an image is directly observed by a transmitted light from the opposite side of the printing surface and is free from such a problem that an image is hard to be observed due to a reflection (back light) of outside light that is not the transmitted light. Moreover, it relates to an ink-jet recording material for a backlit use excellent in fingerprint resistance.
2. Prior Art
As a recording material to be used for an ink-jet recording method, it has been known a recording material which comprises an ink-receptive layer made of a hydrophilic polymer or a porous ink-receptive layer containing a pigment such as amorphous silica, etc. and a hydrophilic polymer, being provided on a support such as a usual paper or the so-called ink-jet recording sheet.
There have been proposed recording sheets obtained by coating a hydrophilic polymer such as starch, polyvinyl alcohol, etc. onto a support as disclosed in, for example, Japanese Provisional Patent Publications No. 080489/1981, No. 174381/1984, No. 220750/1985, No. 32788/1986, No. 160875/1988, No. 69388/1991, and the like.
There have been proposed recording sheets obtained by coating a silicon-containing pigment such as silica, etc. and an alumina sol, with an aqueous binder onto a paper support as disclosed in, for example, Japanese Provisional Patent Publications Nos. 51583/1980, 157/1981, 107879/1982, 107880/1982, 230787/1984, 160277/1987, 184879/1987, 183382/1987, 11877/1989, 21508/1991, 67986/1992 and the like.
Also, in Japanese Patent Publication No. 56552/1991, Japanese Provisional Patent Publications Nos. 188287/1990, 132728/1996, 81064/1998, 119423/1998, 175365/1998, 203006/1998, 217601/1998, 20300/1999, 20306/1999 and 34481/1999, and the like, there have been disclosed ink-jet recording materials using synthetic silica fine particles prepared by a gas phase process (hereinafter referred to as “fumed silica”).
On the other hand, there has been an attempt to produce a film for a medical use by the ink-jet recording method. For those recording sheets, ink-absorption property or transparency is a matter of importance, and in addition, in a medical use where back lighting system is used in which an image is observed by a transmitted light from the opposite side of the printing surface, properties such as an fingerprint resistance and surface glare resistance against a back light are of importance. That is, a problem resides in a difficulty of observation due to surface glare or a stain due to fingerprints during handling. Fingerprint resistance is a property that is not significant in case of using a non-transparent or opaque support but is evident in case of using a light transmitting support. In Japanese provisional Patent Publication No. 276789/1995, there has been disclosed a recording material with a high ink-absorption property and high transparency, comprising a transparent support and provided thereon, a coloring agent receptive layer in which a weight ratio of silica fine particles having an average primary particle size of 10 nm or less and a water soluble polymer is 1.5:1 to 10:1. However, there is no description regarding improvement in surface glare or fingerprint resistance.
In Japanese Provisional Patent Publication No. 237682/1986, there has been proposed that fingerprint resistance is improved by adsorbing a hydrophobic material onto a surface, but there is a defect that printing property is lowered. There has been proposed in Japanese Provisional Patent Publication No. 157286/1998 to improve water resistance and fingerprint resistance by using polyvinyl alcohol with a saponification degree of 78 to 92 mol % and a polymerization degree of 1700 or more and an acrylic emulsion, however, in order to have a sufficient fingerprint resistance, lowering in ink-absorption property and bleeding of ink cannot be avoided, and there was no description regarding improvement in surface glare.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an ink-jet recording material for a backlit use which has high ink-absorption property and high transparency, is excellent in image-reproducing property, particularly in a medical field where it is free from difficulty in observing images due to reflection of outside light when it is used in a back-lighting system in which an image is directly observed by a transmitted light from the opposite side of the printing surface. Further, it is to provide an ink-jet recording material for a backlit use that is excellent in fingerprint resistance.
As a result of extensive and intensive studies, the above objects of the present invention can be accomplished by the means as mentioned below.
(1) An ink-jet recording material for a back lit use having a light transmitting support and an ink-receptive layer provided on the support, wherein the ink-receptive layer comprises a hydrophilic polymer and an inorganic pigment having an average particle diameter of 0.5 to 10 &mgr;m, a Haze value of the ink receptive layer defined by JIS-K-7105 is 25% or less and an image clarity C value of a surface of the ink receptive layer defined by JIS-H-8686 is 85% or less.
(2) An ink-jet recording material for a back lit use having a light transmitting support and an ink-receptive layer provided on the support, wherein the ink-receptive layer comprises inorganic fine particles having an average primary particle diameter of 3 to 50 nm and an average secondary particle diameter of less than 0.5 &mgr;m, a hydrophilic polymer and an inorganic pigment having an average particle diameter of 0.5 to 10 &mgr;m, a Haze value of the ink receptive layer defined by JIS-K-7105 is 25% or less and an image clarity C value of a surface of the ink receptive layer defined by JIS-H-8686 is 85 % or less.
(3) An ink-jet recording material for a back lit use described in either (1) or (2), wherein a contact angle of the surface of the ink-jet recording material for a back lit use with water is 13 to 35°, and a contact angle with linseed oil is 8 to 20°.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, the embodiments of the present invention are explained in detail.
According to the preferred embodiments of the present invention, for the ink-receptive layer coated on the light transmitting support, there are a case where it comprises a hydrophilic polymer, an inorganic pigment with an average particle diameter of 0.5 &mgr;m or more and optionally containing a cationic polymer and a hardening agent (hereinafter referred to as a swelling-type ink-receptive layer) and a case where it comprises inorganic fine particles with an average particle diameter of the secondary particles is less than 0.5 &mgr;m, an inorganic pigment with an average particle diameter of 0.5 &mgr;m or more and a hydrophilic polymer and optionally containing a cross-linking agent, a cationic polymer, a surfactant and the like (hereinafter referred to as a void-type ink-receptive layer). A coating solution of the ink-receptive layer is so coated that a coated layer is formed with a thickness of several tens to several hundreds of &mgr;m, and then it is subjected to drying. In a preferred example of the production method, the ink-receptive layer coated on the light transmitting support is once cooled down in an atmosphere of 20° C. or lower, then dried in a drying process.
The coating solution for the ink-receptive layer before coating is generally kept at a temperature of about 30 to 50° C., and by once cooling down after being coated, it gives a high transparency.
In a general comparison between the swelling-type ink-receptive layer and the void-type ink-receptive layer, the former has high glossiness, while its surface tends to have surface glare and it is inferior in ink-absorption prop
Kaneko Satoshi
Tachikawa Masashi
Kelly Cynthia H.
Manelli Denison & Selter PLLC
Mitsubishi Paper Mills Limited
Shewareged B.
White, Jr. Paul E.
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