JP2001234081A - Light clay for modeling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight clay for forming greatly excellent in deformation resistance when dried and excellent in workability and physical properties such as a touch feeling when used in a handicraft, etc. SOLUTION: This lightweight clay is composed of a micro hollow sphere of a synthetic resin having 20-120 μm particle diameter, polyvinyl alcohol resin, a vinyl acetate resin containing a plasticizer, polyethylene oxide and water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modeling lightweight clay used for handicrafts and the like.

[0002]

2. Description of the Related Art Conventionally, clay has been used for handicrafts and the like. This clay generally has the flexibility of being able to be formed, and is formed into a desired shape by hand. Is formed and dried by natural drying or the like, whereby the cured product is cured, and the shape of the modeled object can be maintained for a long period of time. This clay used to be based on high-weight inorganic clay before, but lightweight clay has been widely used due to its ease of molding and transportation. . As the lightweight clay, for example, a clay obtained by blending a sizing agent, fiber powder, water and the like with a lightweight micro hollow sphere as a main component is known.

One example of this is disclosed in US Pat.
No. 80 proposes a lightweight clay comprising a mixture of micro hollow spheres, polyvinyl alcohol, a gelling agent for polyvinyl alcohol, water, and the like, to reduce the weight of the clay.

[0004]

However, such a lightweight clay has a problem in formability. In other words, clay generally does not adhere to hands, easily deforms clay, can be stably stretched to a thin shape, the stretched surface has smoothness, and the shape is preserved on the molded object Although it is necessary for the conventional lightweight clay to adhere to the hand, it is hard and difficult to deform, or even if deformed, the clay is too elastic and can be stretched to the desired shape It could not be done, the stretched surface was not smooth, or the shape retention after molding was not sufficient. In addition, the molded product after molding and drying using this conventional clay hardens, becomes brittle, and has the disadvantage of losing its deformation durability, such as breaking due to external pressure, and the work produced is It could not be kept stable and it was difficult to store for a long time.

[0005] The clay of the present invention ameliorates such disadvantages,
The following objectives are achieved. INDUSTRIAL APPLICABILITY The present invention is very lightweight, and can be easily lifted and carried by infants and elementary school children at the time of molding, and the product can be easily carried. Gives a touch feeling, has moderate extensibility, and can be easily deformed into a desired shape by hand force at the time of modeling,
An object of the present invention is to provide a shaping clay which has a deformed surface having smoothness, an appropriate hardness, and an excellent shape-retaining property for maintaining a shape formed during shaping. Furthermore, the present invention does not adhere to the hands of the creator at the time of modeling, enabling a comfortable modeling operation,
It is an object of the present invention to provide a modeling clay in which a molded article obtained by drying has excellent durability against bending deformation and the like and can be stored for a long period of time.

[0006]

According to the present invention, a particle size of 20 to 1 is provided.
This is a lightweight clay for molding, which is made of synthetic hollow microspheres of 20 μm, polyvinyl alcohol, vinyl acetate resin, polyethylene oxide, and water.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A synthetic resin micro hollow sphere used in the present invention is formed by heating and foaming a synthetic resin thermally expandable micro sphere containing a liquid such as a hydrocarbon having a low boiling point. It is desirable that the synthetic resin be a copolymer of various combinations of vinylidene chloride, acrylonitrile, acrylate, and the like, but is not limited thereto. The synthetic resin micro hollow spheres preferably have a particle size of 20 to 150 μm. It is desirable that the bulk specific gravity of the synthetic resin micro hollow sphere is about 0.01 to 0.04. Usually, this synthetic resin micro hollow sphere is
A commercially available product in a water-containing state (70 to 90% by weight of water) can be used.

The compounding amount of the synthetic resin hollow microspheres is as follows:
It is preferably 5 to 15% by weight (by dry weight) based on the total weight of the clay, and if it is less than 5% by weight, other components may be increased, stickiness may be lost, and the formability may be impaired, and the weight of the clay is not significantly reduced. If the amount exceeds 15% by weight, the shaped article after drying tends to be easily damaged by external pressure.

Since the synthetic resin hollow microspheres used in the present invention are lightweight, the volume occupied by the clay of the present invention is very large, and occupies most of the total volume of the clay. Furthermore, although the micro hollow spheres can be deformed to some extent, since they are spherical, there is a gap between the micro hollow spheres, and water and other components are formed in a soft kneading state in these gaps. Sometimes it is movable and facilitates modeling, and only the water present in the gaps evaporates during drying, so there is almost no change in volume between wet and dry, and the molded article has excellent shape retention. I have.

The polyvinyl alcohol resin used in the present invention is a partially saponified polyvinyl acetate,
The saponification degree is desirably 80 to 95, particularly 85 to 90 mol%. Here, the polyvinyl alcohol is used in the form of a powder or an aqueous solution, but usually, a powder is often used. When powdered polyvinyl alcohol is used, it is desirable to use a powdered polyvinyl alcohol so that the polyvinyl alcohol does not clump when kneaded with water. The polyvinyl alcohol resin used in the present invention is particularly a modified polyvinyl alcohol resin, and has a 3% aqueous solution viscosity at 400C of 400 to 400%.
900 mpa. s is highly desirable.

[0011] Polyvinyl alcohol binds the micro hollow spheres while maintaining flexibility, and retains the shape of the molded article after molding and drying. The blending amount of the polyvinyl alcohol resin is 5-1 to the total amount of the clay.
0% by weight (expressed in dry weight), particularly 5 to 8% by weight, is preferred. When the blending amount of the polyvinyl alcohol-based resin powder is less than 5% by weight, the tackiness (plasticity, extensibility) during molding
When the decoy exceeds 10% by weight, the clay becomes hard, and the physical properties such as workability and feel when shaping with clay tend to deteriorate.

The vinyl acetate resin used in the present invention includes polyvinyl acetate, polymodified vinyl acetate, ethylene vinyl acetate copolymer resin, vinyl acetate / vinyl versatate copolymer resin, vinyl acetate / acrylic acid copolymer, acetic acid Vinyl acetate resins such as vinyl / acrylate copolymer, vinyl acetate / methacrylic acid copolymer, vinyl acetate / methacrylic ester copolymer, vinyl acetate / acrylamide copolymer, vinyl acetate / diene copolymer It is.
The vinyl acetate resin is used in the form of powder or emulsion, but is usually used in the form of emulsion. When used in the form of an emulsion, it is desirable to use one containing 50% or more of a vinyl acetate resin component.

The vinyl acetate resin used in the present invention has a 59% aqueous solution viscosity at 30 ° C. of 1,000 to 1%.
50,000 cps is desirable. The vinyl acetate resin, together with polyvinyl alcohol, binds the micro hollow spheres while maintaining plasticity, and also maintains the shape of the molded article after molding and drying.

It is desirable that the vinyl acetate resin be added with a plasticizer. Examples of the plasticizer include dibutyl phthalate. The amount of the plasticizer is preferably 4 to 10% by weight based on the weight of the vinyl acetate resin emulsion. The compounding amount of the vinyl acetate resin containing a plasticizer is preferably 1.5 to 7% by weight (expressed in dry weight), particularly preferably 2 to 5% by weight, based on the total amount of the clay.

The use of a polyvinyl alcohol-based resin and a vinyl acetate-based resin in combination allows fine hollow spheres to be bonded while maintaining good flexibility, and at the same time, to maintain the shape of a formed article after forming and drying. Is necessary.
Clay must have good plasticity when wet, so that it can be shaped with the power of children's hands, and must have extensibility that can be stretched to thin and thin shapes. Hardness (shape retention) that can maintain the shape is required, but can be achieved by using a polyvinyl alcohol-based resin and a vinyl acetate-based resin in combination.
Furthermore, the clay must not only avoid cracking and brittleness during drying, but also have durability against deformation such as bending.

The mixing ratio of polyvinyl alcohol and polyvinyl acetate resin containing a plasticizer is 10: 7 to 10: 3 by weight.
It is desirable that If the compounding ratio of the vinyl acetate resin containing a plasticizer exceeds 7, the clay may become sticky and the formability may be impaired. If it is less than 3, the material tends to be easily damaged by an external pressure after drying.

The polyethylene oxide used in the present invention is a polymer obtained by ring-opening polymerization of ethylene oxide, and is a water-soluble highly polymerized polymer having an ether group in the middle and a hydroxyl group at a terminal. The polyethylene oxide used in the present invention has a molecular weight of about 300,000 to
Desirably, it is 1.2 million, especially 600,000 to 800,000. Even a very low concentration aqueous solution shows high viscosity, and the viscosity of a 2.0% by weight aqueous solution at 25 ° C. is 1%.
It is desirably 00 to 2000 cps, particularly 200 to 700 cps (measured with a rotational viscometer). Further, those having a melting point of 65 to 67 ° C are desirable. It has excellent compatibility with synthetic resin micro hollow spheres, polyvinyl alcohol and vinyl acetate.

The polyethylene oxide is used in the form of a powder or an aqueous solution, but usually the powder is often used. When powdered polyethylene oxide is used, it is desirable to use finely powdered polyethylene oxide so that the lump of polyethylene oxide does not occur during kneading with water. Polyethylene oxide not only improves the plasticity and extensibility of the clay at the time of forming the clay, but also improves the adhesiveness of the clay and reduces the adhesion to the hand, thereby making the molding work comfortable. This compounding amount is 0.5 to 1.5% by weight (expressed in dry weight) based on the total amount of clay,
Is preferred. When the blending amount of polyethylene oxide is 0.5
If the amount is less than 1.5% by weight, the extensibility and surface smoothness of the obtained clay at the time of molding are desired. If the amount exceeds 1.5% by weight, the clay may become sticky at the time of molding and adhere to hands.

[0019] In addition to the above, fiber powder can be added to the clay of the present invention. The fiber powder enhances shape retention after shaping and drying, and has an effect of preventing shrinkage. Examples of the fiber powder include powdered pulp, vinylon fiber, powdered cotton, and crushed sheet pulp. Fiber powder length 0.5 ~
Natural fibers, synthetic fibers, etc. of 5.5 mm, especially 1-3 mm, are desirable. The compounding amount is 0.5 to 4 of the total weight of the clay.
% By weight is preferred.

A dispersant may be added to the clay of the present invention in addition to the above. The dispersant enhances the affinity between water and micro hollow spheres, PVA, etc.,
As the dispersant, higher alcohol sulfates,
Examples thereof include sodium polyoxyethylene lauryl ether sulfate and high molecular polycarboxylic acid. The blending amount of the dispersant is 2 to the total weight of the clay.
8% by weight is preferred.

[0021] In addition to the above, a carboxymethylcellulose salt, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, a natural polymer guar gum, and a guar gum derivative can be added to the clay of the present invention. These improve the extensibility, surface smoothness, and texture of the clay, and are preferably contained in an amount of 0.5 to 1.5% by weight based on the total weight of the clay.

[0022] In addition to the above, a humectant can be added to the clay of the present invention. Examples of the humectant include liquid paraffin, sorbitol, polyethylene glycol, propylene glycol and the like. The compounding amount of the humectant is preferably 0.5 to 1.5% by weight based on the total amount of the clay. Further, the mixing amount of water is preferably 50 to 80% by weight, particularly preferably 60 to 75% by weight based on the total weight of the clay.

The clay of the present invention is mainly composed of a large number of lightweight micro hollow spheres (by volume), so that it is lightweight and can be easily lifted or carried by infants and elementary school children at the time of molding. Yes, and the products can be easily carried. Since the clay of the present invention has many fine hollow spheres, which are fine and flexible, the clay of the present invention does not make the creator's hand uncomfortable at the time of modeling and has a moderate flexibility. It can be easily deformed to the desired shape by hand force at the time of molding, and it has moderate hardness and is excellent in shape retention that retains the shape formed at the time of molding. It is excellent. Furthermore, since the clay of the present invention does not stick to the hands of the creator at the time of modeling and is rich in releasability, comfortable modeling work can be performed without soiling the hands and clothes of the creator. The clay of the present invention has excellent durability against bending deformation and the like, and can be stored for a long period of time.

[0024]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, various properties of the obtained lightweight clay were evaluated by the following methods.

(1) Physical Properties of Clay (Adhesion to Hands, Extensibility of Clay, Surface Smoothness, Hardness) The evaluation of the modeling of a molded article by ten clay users using clay is as follows. Was evaluated by the number of people. When 8 to 10 persons are good ◎ When 6 to 7 persons are good ○ When 3 to 5 persons are good △ 0 When 2 persons are good ×

(2) Bending durability test A flat test piece having a length of 30 mm, a width of 120 mm and a thickness of 2 mm was prepared using a water-resistant lightweight clay. This test piece was placed in a dryer and dried at a temperature of 50 ± 2 ° C. for 24 hours, and then placed in a desiccator in a room adjusted to 20 ± 2 ° C.
Cool down to room temperature, take out, and extend 60 m vertically to cover half of the test piece at a position 60 mm from the end of the test piece.
m, width 60mm, thickness 2mm Acrylic plate is fixed so that the ends match, and the test piece (length 60mm) not covered by the acrylic plate is lifted and placed on the acrylic plate. The test piece was bent at the boundary line between the existing portion and the non-existing portion, and the bending angle at the time when the test piece cracked or fractured was measured. This test was performed three times, and the average value was calculated.

Example 1 Methyl methacrylate-acrylonitrile copolymer resin fine hollow particle dispersion (Matsumoto Microsphere F-50E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20-80 μm,
Solid content 15-20% by weight, water 80-85% by weight) 70g
And 10 g of polyvinyl alcohol, 1 g of polyethylene oxide and 4 g of fiber powder were put into a kneader and kneaded well. 10 g of a vinyl acetate resin emulsion (Polysol S-6, manufactured by Showa Polymer Co., Ltd., solid content 59 ± 2% by weight, plasticizer 4 to 10% by weight), and monogen 170
3 g of T (higher alcohol sulfate manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 2 g of water were added and kneaded to produce 100 g of a lightweight clay for modeling. The obtained clay had no sticking to the hands and was not sticky, and was excellent in extensibility, surface smoothness, and hardness of the clay, that is, excellent in feel and workability. Evaluation that 8 to 10 people were good was obtained. As shown in Table 1, the result of the bending bending durability test shows that even at a bending angle of 180 degrees,
No cracks needed.

[0028]

[Table 1]

Example 2 A dispersion of fine hollow particles made of acrylonitrile / vinylidene chloride copolymer resin (Matsumoto Microsphere F-30E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20 to 120 μm, solid content 10 to 15% by weight, water 85) ~ 90% by weight)) 67g
And 13 g of polyvinyl alcohol and 1 g of polyethylene oxide were put into a kneader and kneaded well. This was mixed with a vinyl acetate resin aqueous emulsion (Polysol S-6, manufactured by Showa Kogyo Co., Ltd., solid content: 59 ± 2% by weight, plasticizer 4 to 4%).
(10% by weight), 5 g of Monogen 170T (Daiichi Kogyo Seiyaku Co., Ltd.) and 1 g of water were added, and the mixture was further kneaded to produce 100 g of a lightweight clay for bending and forming.

The obtained clay has no sticking to the hand, has no stickiness, and is excellent in extensibility, surface smoothness, and shape retaining properties of the clay, that is, excellent in feel and workability. Thus, the evaluation that 8 to 10 out of 10 persons were good was obtained. As shown in Table 1, as a result of the bending durability test, even at a bending angle of 180 degrees, no bending occurred and no crack was required.

Comparative Example 1 Methyl methacrylate-acrylonitrile copolymer resin fine hollow particle dispersion (Matsumoto Microsphere F-50E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20-80 μm,
Solid content 15-20% by weight, water 80-85% by weight)) 70
g, polyvinyl alcohol 10 g and fiber powder 4 g were put in a kneader and kneaded well. An aqueous emulsion of vinyl acetate resin (Polysol S manufactured by Showa High Polymer Co., Ltd.)
−6, solid content 59 ± 2% by weight, plasticizer 4 to 10% by weight)
10g, Monogen 170T (Daiichi Kogyo Seiyaku Co., Ltd.)
3 g and 3 g of water are added, and the mixture is further kneaded.
00 g was produced.

The obtained clay has some adhesion to hands and is not sufficient in surface smoothness, that is, not enough in touch and workability.
Only five people were evaluated as good. As shown in Table 1, the results of the bending durability test were as follows.
It didn't break anymore and didn't need any cracks.

Comparative Example 2 Methyl methacrylate-acrylonitrile copolymer resin fine hollow particle dispersion (Matsumoto Microsphere F-50E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20-80 μm,
Solid content 15-20% by weight, water 80-85% by weight)) 70
g, 16 g of polyvinyl alcohol and 1 g of polyethylene oxide were put in a kneader and kneaded well. 3g of monogen 170T (Daiichi Kogyo Seiyaku Co., Ltd.) and 6 of water
g was further added and kneaded to produce 100 g of a modeling lightweight clay. Although the obtained lightweight clay did not use the aqueous vinyl acetate resin emulsion, it was subjected to a bending durability test in the same manner as in Example 1. As shown in Table 1, it was found that the bending angle was 80 °. Broke.

Evaluation of physical properties such as workability and touch of clay was 8 to 10 out of 10 persons attached to the hand, and 6 to 10 persons were extensible.
Seven persons were evaluated as being good, and the smoothness of the surface and the hardness of the clay were evaluated as being good for three to four persons out of ten persons.
According to the results of the bending durability test, the clay containing no vinyl acetate resin aqueous emulsion (containing 4 to 10% of a plasticizer) was used as the clay.
) As compared with the clay using the same. Further, when the aqueous vinyl acetate resin emulsion is considered as a binder for clay and replaced with poval, it is considered that the hardness of the clay becomes harder and also affects the smoothness of the surface.

Comparative Example 3 Micro hollow particles made of methyl methacrylate-acrylonitrile copolymer resin (Matsumoto Microsphere F-50E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20-80 μm, solid content 15-20 wt%, water 80-85) Weight%)) 70 g,
1 g of polyethylene oxide and 4 g of fiber powder were put in a kneader and kneaded well. To this, vinyl acetate resin aqueous emulsion (solid content 60 ± 3%, plasticizer 4-10% contained)
20g and Monogen 170T (Daiichi Kogyo Seiyaku Co., Ltd.) 3
g and 2 g of water were added, and the mixture was further kneaded to produce 100 g of a bent high-strength lightweight clay (kneading time was 30 minutes, 4 minutes).
0 minutes and 50 minutes). The obtained lightweight clay was too sticky to be sticky and could not be used as a clay capable of producing a handicraft work, and a test piece for a bending durability test could not be prepared.

Comparative Example 4 Micro hollow particles made of a methyl methacrylate-acrylonitrile copolymer resin (Matsumoto Microsphere F-30E manufactured by Matsumoto Yushi Co., Ltd., average particle size 20-120 μm, solid content 10-15 wt%, water 85-90) Weight)) 70 g
And 10 g of polyvinyl alcohol, 1 g of polyethylene oxide and 4 g of fiber powder were put into a kneader and kneaded well. This was mixed with a vinyl acetate resin aqueous emulsion (Polysol PS manufactured by Showa Kogaku Kagaku Co., Ltd .;
%, No plasticizer) and 3 g of Monogen 170T (Daiichi Kogyo Seiyaku Co., Ltd.) were added and kneaded to produce 100 g of a bent high-strength lightweight clay.

The obtained lightweight clay was subjected to a bending durability test in the same manner as in Example 1. As shown in Table 1, it was broken at a bending angle of 90 °. Evaluation of physical properties such as workability and touch of clay is adhesion to hands and extensibility is 8 to 1 for 10 persons.
0 was evaluated as good, and the surface smoothness and the hardness of the clay were evaluated as being good for 6 to 7 out of 10 persons.
From these results, it was found that the clay using the vinyl acetate resin aqueous emulsion containing no plasticizer had a lower bending durability than the clay using the vinyl acetate resin aqueous emulsion (containing 4 to 10% of the plasticizer). became.

[0038]

As is apparent from the above description, according to the present invention, the deformation durability during drying is extremely excellent, and the workability and the physical properties such as touch of clay used in handicrafts and the like are excellent. It has become possible to provide lightweight clay.

Claims (3)

[Claims] 1. A lightweight clay for molding, comprising synthetic resin micro hollow spheres having a particle size of 20 to 120 μm, polyvinyl alcohol resin, vinyl acetate resin containing a plasticizer, polyethylene oxide, and water. 2. The lightweight clay for molding according to claim 1, wherein the compounding ratio of polyvinyl alcohol and vinyl acetate resin is 10: 7 to 10: 3 by weight. 3. A synthetic resin micro hollow sphere having a particle size of 20 to 120 μm, 5 to 15% by weight, a polyvinyl alcohol resin 5 to 5% by weight.
10% by weight, 1.5 to 7% by weight of a vinyl acetate resin containing a plasticizer, 0.5 to 1.5% by weight of polyethylene oxide,
A lightweight clay for modeling, comprising 50 to 80% by weight of water.