Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-11-03
2002-09-03
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S503000, C524S803000, C524S378000
Reexamination Certificate
active
06444728
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to modeling lightweight dough for hand crafting used by a worker, such as children and artist.
2. Description of the Prior Art
Heretofore, dough has been used for hand crafting. Generally, dough is plastic so as to be used for forming, can be deformed into a desired shape by hands to form a craft, dried naturally to harden it, and the shape of the craft can be maintained for a long time. Inorganic heavyweight clay has been used previously as the main component of the dough; however, currently lightweight dough has been used widely instead of heavyweight clay because of easy modeling and easy carrying. Lightweight dough that contains, for example, lightweight hollow microspheres as the major component in volume, and binder, fiber powder, and water as the minor component in volume has been known.
An example of lightweight dough containing hollow microspheres, polyvinyl alcohol, polyvinyl alcohol gelling agent, and water has been proposed in U.S. Pat. No. 5,506,280 to realize the lightweight dough.
However, the above-mentioned lightweight dough is not sufficient in formability or workability. In detail, it is necessary for the dough to be rendered non-sticky to hand, easily deformable, stably ductile for forming to a fine shape, smooth on the surface of the stretched shape, and long shape preservation of the modeled product. However, the conventional lightweight dough does not sufficiently satisfy the above-mentioned requirements. In detail, the conventional lightweight dough is still sticky to hand, hard to deform easily, too elastic to stretch dough to obtain a desired shape even though it is deformed, not sufficiently smooth on the stretched surface, or insufficient in shape preservation after modeling. Furthermore, a modeled product made of the conventional dough becomes brittle after modeling and drying, and is poor in deformation resistance, that causes the breaking of the model product when the external force is exerted. The conventional dough is disadvantageous as described hereinabove, the craft modeled by use of the conventional dough cannot be maintained stably, and the long time preservation is difficult due to weakness to the external force.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide modeling dough that is lightweight so that children can lift and carry it easily for modeling and can carry the modeled craft easily.
It is another object of the present invention to provide modeling dough that gives comfortable hand feeling to a worker during modeling, is suitably ductile so that it is easily deformable to a desired shape by use of a force of the hand during modeling, is smooth on the deformed surface, and is suitably hard so that the modeled shape is maintained and excellent in shape preservation.
It is still another object of the present invention to provide modeling dough that is not sticky to the hand of a worker during modeling, excellent in releasability, stain-resistant on hand and clothes of a worker, and enables comfortable modeling work.
It is a further object of the present invention to provide modeling dough that forms a modeled product obtained by modeling and drying of the dough of the present invention excellent in resistance to bending deformation and a model product excellent in long preservation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a modeling dough comprising synthetic resin hollow microspheres having a particle diameter of 20 to 120 &mgr;m, polyvinyl alcohol, vinyl acetate resin, and water, and a modeling dough comprising synthetic resin hollow microspheres having a particle diameter of 20 to 120 &mgr;m, polyvinyl alcohol, vinyl acetate resin, polyethylene oxide, and water.
The synthetic resin hollow microspheres used in the present invention are hollow microspheres formed by heating synthetic resin heat-expandable minute spheres containing low-boiling point hydrocarbon or the like. The synthetic resin used is desirable various copolymers selected from vinylidene chloride, acrylonitrile, and acrylic ester, but not limited to these copolymers. The particle diameter of the synthetic resin hollow microsphere is desirably 20 to 150 &mgr;m. The specific gravity of the synthetic resin hollow microsphere is desirably about 0.01 to 0.04. Usually, aqueous dispersion of the synthetic resin hollow microspheres that contain some water (containing 70 to 90% by weight of water) is commercially available, and such synthetic resin hollow microspheres may be used.
The content of synthetic resin hollow microspheres is preferably 5 to 15% by weight (based on dry weight) to the total weight of the dough. If the content is less than 5% by weight (other components are contained much), then the dough is likely sticky and not sufficient in formability, and likely not sufficient in lightweight property of the dough; on the other hand, if the content is more than 15% by weight, then the modeled product is apt to be weak to the external force.
Because the synthetic resin hollow microspheres used in the present invention are lightweight, the volume in the dough of the present invention are very large, and the synthetic resin hollow microspheres occupy the majority of the dough volume. Furthermore, because the hollow microsphere is spherical, there are spaces among hollow microspheres, spaces accommodate water and other ingredients that form soft mixture so as to be movable during modeling and so as to make modeling or manuplating easy. Because only water the majority of which is in the space among hollow microspheres is evaporated during drying, the volume scarcely changes with concomitant change from wet state to dry state, and the modeled product is excellent in shape preservation.
Polyvinyl alcohol used in the present invention is partially hydrolized polyvinyl acetate, and the degree of hydrolysis is desirably 80 to 95 mol %, and more desirably 85 to 90 mol %. Polyvinyl alcohol in the form of powder or aqueous solution is used herein, and powder is usually used. Fine powder is desirably used so that powder does not coagulate each other when the powder is mixed with water.
Modified polyvinyl alcohol having a high viscosity of 400 to 900 mpa.s measured under conditions of 3% aqueous solution at 20° C. is used desirably as the polyvinyl alcohol used in the present invention.
Polyvinyl alcohol functions to bind hollow microspheres maintaining plasticity during modeling and to maintain the shape of the modeled product after modeling and drying.
The content of polyvinyl alcohol is preferably 5 to 10% by weight to the total dough (expressed in dry weight base), and more preferably 5 to 8% by weight. If the content of polyvinyl alcohol is less than 5% by weight, then the plasticity and ductility is likely not sufficient; on the other hand, if the content exceeds 10% by weight, then the dough is too hard, and the workability for modeling and hand feeling property become likely poor.
Examples of vinyl acetate resin used in the present invention include vinyl acetate based resins, such as polyvinyl acetate, modified polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl acetate-acrylic acid copolymer, vinyl acetate-acrylic ester copolymer, vinyl acetate-methacrylic acid copolymer, vinyl acetate-methacrylic ester copolymer, and vinyl acetate-acryl amide copolymer. Vinyl acetate resin is used in the form of powder or emulsion, and usually emulsion is used. An emulsion containing vinyl acetate resin component of 50% or more is desirably used.
Vinyl acetate resin having a viscosity of 1,000 to 150,000 mpa.s measured under conditions of 59% aqueous solution at 30° C. is preferable used in the present invention.
Vinyl acetate resin functions to bond hollow microspheres together with polyvinyl alcohol with maintaining plasticity during modeling, and functions to maintain the shapes of the modeled product after modeling and drying.
Vinyl acetate resin emulsion containing plasticizer is desirably used. Dibutyl phthalate or the like is exem
Padico Co., Ltd.
Yoon Tae H.
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