Paper making and fiber liberation – Processes and products – With coating after drying
Reexamination Certificate
2000-05-22
2001-07-31
Pyon, Harold (Department: 1772)
Paper making and fiber liberation
Processes and products
With coating after drying
C162S135000, C162S112000, C162S158000, C162S164400, C427S387000, C427S391000, C428S447000, C428S452000
Reexamination Certificate
active
06267842
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to a water-based treatment agent for tissue paper, and to a tissue paper treatment method. More specifically, the invention relates to (i) a water-based treatment agent for tissue paper which can suppress any feeling of slipperiness or wetness in tissue papers such as ordinary tissue paper or toilet paper, so that the papers have a dry touch, ample smoothness, and a clean, smooth, tactile impression, and which provides the paper with superior softness; and (ii) a tissue paper treatment method for obtaining tissue paper having superior softness in which any feeling of slipperiness or wetness is suppressed, so that the paper has a dry touch, ample smoothness, and a clean, smooth, tactile impression.
BACKGROUND OF THE INVENTION
When ordinary tissue paper and toilet paper lacks softness and smoothness, the frequent use of such paper can result in rough, red, and painful skin. Therefore, many methods have been proposed to solve this problem. For example, one technique involves a method in which such tissue paper is treated with a dimethylpolysiloxane or a dimethylpolysiloxane having a functional group such as an amino group, carboxy group, hydroxy group, ether group, polyether group, aldehyde group, ketone group, amido group, ester group, or thiol group, and this method is described in Japanese Patent Application Kokai No. Hei 2-224626, and Japanese Patent Application Kokai No. Hei 3-900, the English equivalents of which are EP 347153, U.S. Pat. Nos. 5,059,282, and 5,164,046. Another technique involves a method in which such papers are treated with an emulsion of an organopolysiloxane containing amino groups, and a diorganopolysiloxane containing polyether groups, and this method is described in Japanese Patent Application Kokai No. Hei 6-311943. Other known techniques include a method in which such papers are treated with a diorganopolysiloxane and a polyhydric alcohol, as described in Japanese Patent Application Kokai No. Hei 7-145596.
However, it has been found that tissue paper treated according to these methods does not have satisfactory softness, but that the paper has a rough feeling and an unsatisfactory hand. This is especially true when the paper is treated with a diorganopolysiloxane containing an amino group, in which case, an excessively slippery feeling is produced, so that the sensation produced by contact with the skin of the hands is unsatisfactory. Furthermore, when the paper is treated with a diorganopolysiloxane containing a polyether group, the smoothness and slipping sensation is unsatisfactory.
BRIEF SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide
(i) a water-based treatment agent for tissue paper which suppresses any feeling of slipperiness or wetness in tissue paper such as ordinary tissue paper or toilet paper, so that the paper has a dry touch, ample smoothness, and a clean, smooth, tactile impression, and which imparts paper with superior softness; and
(ii) a tissue paper treatment method for obtaining tissue paper having superior softness in which any feeling of slipperiness or wetness is suppressed, so that the paper has a dry touch, ample smoothness, and a clean, smooth, tactile impression.
The water-based treatment agent for tissue paper is characterized by it being an agent consisting of a silicone oil emulsion in which crosslinked silicone particles with a mean particle size of 0.01-100 &mgr;m are contained in silicone oil droplets with a mean particle size of 0.05-500 &mgr;m, which are dispersed in water. The particle size of the crosslinked silicone particles is smaller than the particle size of the silicone oil droplets.
Likewise, the tissue paper treatment method is characterized by it being one in which tissue paper is treated with a water-based treatment agent for tissue paper which consists of a silicone oil emulsion in which crosslinked silicone particles with a mean particle size of 0.01-100 &mgr;m are contained in silicone oil droplets with a mean particle size of 0.05-500 &mgr;m, which are dispersed in water. Again the particle size of the crosslinked silicone particles is smaller than the particle size of the silicone oil droplets.
These and other features of the invention will become apparent from a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
The water-based treatment agent for tissue paper according to this invention consists of a silicone oil emulsion in which crosslinked silicone particles are contained in silicone oil droplets that are dispersed in water. In this emulsion, the crosslinked silicone particles are obtained by crosslinking a crosslinkable silicone composition.
Examples of crosslinkable silicone compositions include compositions crosslinked by a hydrosilylation crosslinking reaction, compositions crosslinked by a condensation crosslinking reaction, compositions crosslinked by an organic peroxide crosslinking reaction, and compositions crosslinked by a high-energy radiation crosslinking reaction. Most preferred are compositions crosslinked by hydrosilylation crosslinking reactions and compositions crosslinked by condensation crosslinking reactions.
In the emulsion, there are no limitations on the type of silicone oil used to form the silicone oil droplets, but it is preferred that the silicone oil be a silicone oil with a linear molecular structure, a linear molecular structure with some degree of branching, a cyclic molecular structure, or a branched molecular structure. Silicone oils with linear molecular structure are most preferred. The silicone oil should be a silicone oil that does not participate in the crosslinking reaction that takes place when the crosslinked silicone particles are formed, i.e., a silicone oil that does not undergo a crosslinking reaction and that does not hinder crosslinking reactions.
When the crosslinked silicone particles are obtained by a hydrosilylation crosslinking reaction, the silicone oil should have no alkenyl groups or hydrogen atoms bonded to silicon atoms in its molecule. Some representative examples include dimethylpolysiloxanes in which both ends of the molecular chain are terminated with trimethylsiloxy groups, methylphenylpolysiloxanes in which both ends of the molecular chain are terminated with trimethylsiloxy groups, dimethylsiloxane/methylphenylsiloxane copolymers in which both ends of the molecular chain are terminated with trimethylsiloxy groups, dimethylsiloxane-methyl (3,3,3-trifluoropropyl) siloxane copolymers in which both ends of the molecular chain are terminated with trimethylsiloxy groups, cyclic dimethylsiloxanes, cyclic methylphenylsiloxanes, and silicone oils in which hydrogen atoms in hydrocarbon groups on side chains and ends of the silicone oil are substituted by epoxy groups, carboxyl groups or polyether groups.
When the crosslinked silicone particles are obtained by a condensation crosslinking reaction, the silicone oil should have no silanol groups, hydrogen atoms bonded to silicon atoms, or hydrolyzable groups bonded to silicon atoms in its molecule. Some representative examples of suitable silicone oils are dimethylpolysiloxanes in which both ends of the molecular chain are terminated with trimethylsiloxy groups, methylphenylpolysiloxanes in which both ends of the molecular chain are terminated with trimethylsiloxy groups, dimethylsiloxane/methylphenylsiloxane copolymers in which both ends of the molecular chain are terminated with trimethylsiloxy groups, dimethylsiloxane-methyl (3,3,3-trifluoropropyl) siloxane copolymers in which both ends of the molecular chain are terminated with trimethylsiloxy groups, cyclic dimethylsiloxanes, cyclic methylphenylsiloxane, dimethylpolysiloxanes in which both ends of the molecular chain are terminated with dimethylvinylsiloxy groups, dimethylsiloxane/methylvinylsiloxane copolymers in which both ends of the molecular chain are terminated with dimethylvinylsiloxy groups, methylvinylpolysiloxanes in which both ends of the mole
Ishikawa Hiroki
Kobayashi Kazuo
Morita Yoshitsugu
Naganawa Tsutomu
Ona Isao
Cesare James L. De
Dow Corning Toray Silicone Company, Ltd.
Pyon Harold
Tsoy Elena
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