Compositions: coating or plastic – Coating or plastic compositions – Silicon containing other than solely as silicon dioxide or...
Reexamination Certificate
2000-08-04
2002-06-04
Brunsman, David (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Silicon containing other than solely as silicon dioxide or...
C106S177100, C524S188000, C162S158000, C162S164400, C162S177000
Reexamination Certificate
active
06398860
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to a sizing agent composition for printing paper, and more specifically relates to a sizing agent composition for printing paper which improves the printing characteristics and sheet separating characteristics of printing paper.
Conventionally, when printing is performed by an electronic copier using recycled paper, especially in the rainy season when the humidity is high, problems such as the simultaneous feeding of two sheets due to a deterioration in the sheet separating characteristics, and the breaking of printed characters due to a deterioration in the printing characteristics, are encountered. Furthermore, in cases where a facsimile transmission is performed with several sheets of facsimile paper in a stack, the transmission may be made with two or three sheets superimposed if the sheet separating characteristics are poor, so that the entire text is not transmitted. One cause of such problems is that the tacky adhesion of the sizing component (sizing agent), such as a polyvinyl alcohol, starch sizing, or carboxymethylcellulose, etc., that adheres to the surface of the paper increases as the humidity rises. In order to prevent such problems, a method has been proposed in which a polyalkylsiloxane modified by means of carboxyl groups, hydroxy groups, epoxy groups, amino groups, isocyanate groups, thioether groups, or mercapto groups, etc., is used as an offset-preventing liquid (see Japanese Patent Application Kokoku No. Sho 58-52589). Furthermore, a method in which a recording paper is coated with a pigment, a polyvinyl alcohol, and a silicone emulsion (see Japanese Patent Application Kokoku No. Hei 3-24908), a method in which a silicone oil is introduced into a thermally fusible ink layer (see Japanese Patent Application Kokai No. Hei 3-42280), and a method in which a coating liquid prepared by dissolving an organic resin and a silicone oil in an organic solvent is applied as a coating to a heat-transfer recording paper (see Japanese Patent Application Kokai No. Hei 4-142989) are also known.
However, in the case of the abovementioned method using an offset-preventing liquid, the following drawback is encountered: specifically, if copying is continued over a long period of time, the heat rolls or heating rolls become worn so that the roll surfaces become rough, thus causing a gradual deterioration in the release characteristics. Furthermore, in the case of the abovementioned method using a silicone emulsion, the emulsion is caused to break down by the numerous ingredients used, and in the case of the abovementioned method using an organic solvent, consideration must be given to the possibility of contamination of the working environment and danger of fire. Furthermore, in the case of the abovementioned methods, various types of printing papers cannot be provided with sufficient sheet separating characteristics or printing characteristics suitable for color copying. For example, even in cases where a facsimile transmission is performed by re-utilizing several receiving sheets “as is” in the facsimile machine, two or three sheets may be superimposed during the transmission so that the entire text cannot be transmitted.
Because of such problems, there is a demand for improved sheet separating characteristics and printing characteristics, and in particular, there is a demand for superior sheet separating characteristics which allow re-utilization of receiving sheets in a facsimile machine. The object of the present invention is to provide a sizing agent composition for printing paper which can provide various types of printing papers, such as papers used in black and white electronic copiers used in business applications, papers used in color copiers, papers used in ink jet printers, and receiving papers used in facsimile machines, with superior sheet separating characteristics, printing characteristics, and copying characteristics.
SUMMARY OF INVENTION
The present invention is a sizing agent composition for printing paper comprising
(A) a water-soluble diorganopolysiloxane described by formula
where each R is independently selected from the group consisting of a hydrogen atom, methyl group, and ethyl group, each R
1
is an independently selected monovalent hydrocarbon group comprising 1 to 20 carbon atoms, Q is an organic group comprising an amino group or quaternary ammonium salt, m is an integer equal to or greater than 2, n is 0 or an integer equal to or greater than 1, and (m+n) is in the range of 2 to 100;
(B) a sizing agent; and
(C) water.
DESCRIPTION OF INVENTION
The present invention is a sizing agent composition for printing paper comprising
(A) a water-soluble diorganopolysiloxane described by formula
where each R is independently selected from the group consisting of a hydrogen atom, methyl group, and ethyl group, each R
1
is an independently selected monovalent hydrocarbon group comprising 1 to 20 carbon atoms, Q is an organic group comprising an amino group or quaternary ammonium salt, m is an integer equal to or greater than 2, n is 0 or an integer equal to or greater than 1, and (m+n) is in the range of 2 to 100;
(B) a sizing agent; and
(C) water.
To describe the respective components of the present invention in detail, component (A) is a component which not only improves the sheet separating characteristics by providing the printing paper with release characteristics, lubrication, smoothness, and anti-blocking characteristics, but also improves the water resistance by making the binder component comprising component (B) hydrophobic, and which also imparts the effect of fixing pigments to ink jet printer media and sublimation type printer media. The diorganopolysiloxane comprising component (A) is a water-soluble siloxane described by Chemical Formula 1.
In the present composition with regards to the diorganopolysiloxane, the term “water solubility” refers to the property of dissolving and dispersing in cases where 5 g of the diorganopolysiloxane is added to 100 g of water, and the resulting mixture is agitated. This may refer to dissolution into a transparent state, or uniform dispersion with some degree of turbidity. In the abovementioned Chemical Formula 1, each R is independently selected from the group consisting of a hydrogen atom, methyl group, and ethyl group. R is generally a hydrogen atom or a methyl group, and is preferably a hydrogen atom from the standpoint of water solubility. Each R
1
is an independently selected monovalent hydrocarbon group comprising 1 to 20 carbon atoms; with specific examples of such groups including saturated aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, and dodecyl; unsaturated aliphatic hydrocarbon groups such as vinyl, allyl, and hexenyl; saturated alicyclic hydrocarbon groups such as cyclopentyl and cyclohexyl; aromatic hydrocarbon groups such as phenyl, tolyl, and naphthyl; aralkyl groups such as styrene and methylstyrene; and halogen-substituted hydrocarbon groups in which some of the hydrogen atoms bonded to the carbon atoms of the abovementioned groups are replaced by halogen atoms. Among these groups represented by R
1
, methyl groups are most common. However, the groups indicated by R
1
need not all be the same within the molecule; combinations of two or more different types of groups may be used. Especially in cases where the present composition is used on full-color or ink jet printer papers or on sublimation type printer papers, it is desirable from the standpoints of affinity for and compatibility with printing pigments such as red, yellow, blue, and black pigments, that at least a portion of the groups represent by R
1
have 2 to 20 carbon atoms, preferably 6 to 15 carbon atoms, and most preferably 8 to 14 carbon atoms.
In Chemical Formula 1, Q represents an organic group comprising an amino group or quaternary ammonium salt; a group in which a nitrogen atom is bonded to a silicon atom of the principal chain via a carbon atom is desirable. In specific terms, organic grou
Ishikawa Hiroki
Naganawa Tsutomu
Ona Isao
Takimoto Tadashi
Brunsman David
Dow Corning Toray Silicone Co. Ltd.
Scaduto Patricia M.
Troy Timothy J.
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