Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Noninterengaged fiber-containing paper-free web or sheet...
Reexamination Certificate
2000-10-23
2001-11-13
Dixon, Merrick (Department: 1774)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Noninterengaged fiber-containing paper-free web or sheet...
C428S200000, C428S300700, C428S301400
Reexamination Certificate
active
06316088
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a dispersion of a hot-melt sheet powder used for coating a hot-melt adhesive powder on a sheet such as a cloth, a non-woven fabric, and the like and said sheet may be used as a heat sensitive adhesive sheet, a thermoformable fiber sheet, and used in an interior and a carpet.
BACKGROUND OF THE INVENTION
To give a heat sensitive adhesion property, a hot-melt adhesive powder is coated on a sheet such as a cloth, a non-woven fabric and the like. Hitherto, to coat said hot-melt adhesive powder on said sheet, a method A wherein an aqueous dispersion in which the hot-melt adhesive powder is dispersed is coated on the sheet by using a mesh roller, a method B wherein said hot-melt adhesive powder is strewed on the sheet, and the like have been provided.
Nevertheless, the method A has a disadvantage that said mesh roller is apt to be clogg by the nap of the cloth or the non-woven fabric and the method B has a disadvantage that it is difficult to hold said hot melt adhesive powder on the surface of the cloth or the non-woven fabric since a considerable amount of said hot-melt adhesive powder enters into the space between the naps of the cloth or the non-woven fabric resulting in a poor heat sensitive adhesion.
To solve the above described disadvantages, a dispersion in which a hot-melt adhesive powder is dispersed in the water the viscosity of which is increased by adding a thickener has been provided. Said dispersion has a structural viscosity such that said dispersion may not enter into the space between the naps to be held on the surface of the cloth or the non-woven fabric and said hot melt adhesive powder is effectively fixed on the surface of the cloth or the non-woven fabric.
DISCLOSURE OF THE INVENTION
Hitherto, polysodiumacrylate has been used for a thickener of said dispersion of said hot-melt adhesive powder. Nevertheless, since polysodiumacrylate has a big moisture absorption property and when polysodiumacrylate is dissolved in the water, clod is apt to be produced and as a result, a long time is necessary to dissolve polysodium acrylate in the water. Further, the dispersion in which polysodiumacrylate is used for thickening does not show the plastic flow and cannot prevent the sedimentation of said hot-melt adhesive powder completely, so the stirring of said dispersion is necessary. If the stirring is not enough, the coating of said hot-melt powder on the sheet may be uneven.
Accordingly, the object of the present invention is to provide the dispersion of a hot-melt adhesive powder in which the sedimentation of said hot-melt adhesive powder is effectively prevented and the product having an uniform quality by using said dispersion.
To attain the above described object, the present invention provides a dispersion of a hot-melt adhesive powder consisting of the water and a hot-melt adhesive powder which is dispersed in said water wherein an alkali-thickening type thickener is used for thickening of said dispersion. It is desirable to select an alkali-thickening type acrylic emulsion and/or a slightly cross-linked polyacrylic emulsion. Herein “slightly cross linked” means “cross linked in low density so as to maintain water soluble property”.
A desirable method to prepare said dispersion is the method in which a hot-melt adhesive powder is dispersed and said alkali-thickening type thickener is added in the water and then an alkali agent is added for thickening or an alkali-thickening type thickener is added in the water and then an alkali agent is added for thickening followed by dispersing a hot-melt adhesive powder but the method in which a hot-melt adhesive is dispersed and an alkali agents added in the water and then an alkali-thickening type thickener is added for thickening may be applicable.
Said dispersion of a hot-melt adhesive powder using an alkali-thickening type thickener shows plastic flow to prevent substantially the sedimentation of the hot-melt adhesive powder, stirring said dispersion is not always necessary.
Further, when said alkali-thickening type thickener is added in water before adding an alkali agent, the viscosity of the water may not be remarkably increased such that said alkali-thickening type thickener can be dissolved uniformly in the water. Especially, when an acrylic emulsion as an alkali-thickening type thickener is used, said acrylic emulsion is very easy to disperse in the water and when a slightly cross-linked polyacrylic acid is used, said slightly cross-linked polyacrylic acid can be dispersed and dissolved uniformly in the water without producing clod.
The product using said dispersion of a hot-melt adhesive powder such as a heat sensitive adhesive sheet, a thermoformable fiber sheet, and a carpet, and further an interior or a molded fiber sheet using said sheet have an uniform quality since a hot-melt adhesive powder is uniformly coated on said sheet when said dispersion of a hot-melt adhesive powder is sprayed to said sheet.
Accordingly, the present invention further provides a heat sensitive adhesive sheet manufactured by the process consisting of spraying said dispersion on a base sheet and drying, and a synthetic resin may be impregnated in said sheet. When said base sheet has gas permeability, said dispersion is preferably coated by spraying on one side of said base sheet by forming a vacuum on the other side of said base sheet.
The present invention further provides an interior using said heat sensitive adhesive sheet as a surface layer by attaching it on a base of the interior, a thermoformable fiber sheet manufactured by the process consisting of spraying said dispersion to fiber and forming a sheet by using said fiber and a carpet having dotted backing layer on its backside manufactured by the process consisting of spraying said dispersion on the backside of said carpet and drying.
DETAILED DESCRIPTION
In the present invention, as hot-melt adhesive, polyoelfin type resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like,modified polyolefin type resin, polyvinyl chloride, polyurethane, polyester, polyester copolymer, polyamide, polyamide copolymer and the like may be used singly or as a mixture of two or more kinds. The particle size of said hot-melt adhesive is usually in the range between 50 to 300 mesh.
A thickener used in the present invention is an alkali-thickening type thickener. A desirable alkali-thickening type thickener is an alkali-thickening type acrylic emulsion and the other desirable alkali-thickening type thickener is a slightly cross-linked polyacrylic acid.
Said alkali-thickening type acrylic emulsion may include a copolymer of acrylic ester and &agr;, &bgr;-unsaturated carboxylic acid, a copolymer of acrylic ester, another vinyl monomer(s) which can be copolymerized with said acrylic ester, and &agr;, &bgr;-unsaturated carboxylic acid.
As said acrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfury 1 methacrylate, stearyl methacrylate, lauryl methacrylate, &bgr;-hydroxyethyl acrylate, &bgr;-hydroxyethyl methacrylate, &bgr;-hydroxypropyl acrylate, &bgr;-hydroxypropyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, glycidyl methacrylate and the like may be used.
As said &agr;, &bgr;-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, atropic acid, citraconic acid and the like may be used.
As a vinyl monomer which can copolymerize with said acrylates, a vinyl ether monomer such as methylvinyl ether, ethylvinyl ether, n-propylvinyl ether, n-butylvinyl ether, isobutylvinyl ether and the like, styrene and styrene derivative(&agr;-methlystyr
Ito Kuninori
Kioka Norihiko
Ogawa Masanori
Cooper & Dunham LLP
Dixon Merrick
Dowden Donald S.
Nagoya Oilchemical Co., Ltd.
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