JPH0388757A - Production of clay for work - Google Patents

Abstract

PURPOSE:To obtain clay for work which is excellent in tackiness, the touch, moldability and viscoelasticity and does not discolor by mixing PVA with boric acid and/or borax in the existence of water and mixing the obtained gellike substance with clay base material for work made of starchy material main body. CONSTITUTION:Gellike substance is prepared by mixing PVA with boric acid and/or borax in the existence of water. As the blending rate, about 1-20 pts.wt. PVA and about 1-60 pts.wt. water are preferably utilized for 1 pts.wt. at least one of boric acid and/or borax. Clay for work is obtained by mixing this previously prepared gellike substance with the clay base material for work in which starchy material (e.g. wheat powder, potato starch) is incorporated as a main raw material. Thereby, clay for work excellent in tackiness and resistance to discoloring is produced because the gellike substance of boric acid for a raw material is previously prepared and blended with the clay base material for work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing working clay based on starchy materials.

[Conventional technology]

Craft clay, which is made mainly from starchy materials, is highly safe, has little viscosity change due to temperature, does not bleed oil, is odorless, and is easy to obtain materials, so it has been widely used in traditional learning. - Widely used in place of play clay (e.g. clay made by kneading bentonite, wax or paraffin with oil, or clay based on plastic or rubber). Moreover, in addition to the above-mentioned properties, craft clay made mainly from starchy materials has excellent moldability and coloring properties, so it is not only used for learning and play, but also for making dolls, flowers, etc. Recently, it has come to be used in various ways as a plastic material for manufacturing various crafts.

Craft clay (which uses starchy materials as the main raw material)
(hereinafter referred to as "starchy working clay") is usually made by adding a synthetic resin emulsion such as a polyvinyl acetate emulsion, a salting-out astringent, a filler, a wetting lubricant, borax, and other additives to a starchy material. It is manufactured by kneading.

Although such conventional starchy clay has the above-mentioned good properties, it tends to turn brown in a short period of time, especially when wheat flour is used as the main starchy material. This browning, especially when colored clay, results in extremely poor product quality and color tone, making it difficult to manufacture workpieces with the desired color. In addition, when raw starch is used as a starchy material, the starch's α
This gelatinization of starch does not result in a good clay. Therefore, it is necessary to control and adjust the temperature during clay production so that it is always kept below about 60°C. .

[Contents of the invention]

The present inventors aimed to obtain starchy craft clay that does not require strict temperature control during clay production and that can maintain a beautiful color tone without discoloring for a long period of time even after the product is completed. I have continued my research. As a result, if a gel is made in advance from one or both of boric acid and borax and polyvinyl alcohol, and this gel is blended into a craft clay base material based on a starchy material to produce clay, The present invention has been completed based on the discovery that the above object can be achieved.

Therefore, the present invention prepares a gel-like material in advance by mixing boric acid and/or borax and polyvinyl alcohol in the presence of water, and uses the gel-like material as a clay material for construction mainly made of starchy material. This is a method for producing clay for construction, which is characterized by mixing it into a base material.

In the present invention, the above-mentioned gel-like material is usually made of polyvinyl alcohol per 1 part by weight (hereinafter, parts by weight is simply referred to as parts) of at least one of boric acid and borax (hereinafter referred to as "boric acid/1!l sand"). About 1-20 parts of alcohol and about 1-20 parts of water
It can be manufactured by mixing at a ratio of 60 parts. Among them, when boric acid/borax = polyvinyl alcohol trihydrate is mixed in a weight ratio of about 1:2 to 15:1 to 60, it can be easily mixed and dispersed into a craft clay base material made of starchy materials, etc. Moreover, it is possible to obtain a gel-like material that improves the quality (color fastness, adhesion, texture, moldability, viscoelasticity, etc.) of the produced craft clay.

In this case, any polyvinyl alcohol that can be dissolved or swelled in water or hot water can be used, and modified polyvinyl alcohol can also be used.

The mixing of the three components, borax III/borax, polyvinyl alcohol, and water, can be carried out by any method, for example, by mixing the three components at the same time, or by mixing one of the boric acid/W'A sand and polyvinyl alcohol in advance. This can be done by mixing or dissolving in water and adding the rest to this, or by separately mixing or dissolving boric acid/borax and polyvinyl alcohol in water and then mixing both. Here, the mixing of the three components is usually carried out at about 30 to 90°C. In particular, an aqueous solution is formed in advance from polyvinyl alcohol and water, and this is mixed with a previously formed boric acid/Ta sand aqueous solution and
Mixing and stirring at 80° C. is preferable in order to quickly form a uniform gel-like material. In this case, the concentration of the polyvinyl alcohol aqueous solution is adjusted to about 5 to 30% by weight, and boric acid/
A concentration of the aqueous borax solution of about 2-15% by weight is preferred for gel formation.

The gel thus prepared can be used immediately as is for the production of construction clay, or it can be stored in a container or other packaging material and used at any time for the production of construction clay. You can.

If stored, it is usually about 10-25° CI7'1
From the viewpoint of clay suitability, it is preferable to store it at a cold temperature.

Boric acid/1ill! ! The gel-like material prepared by mixing sand, polyvinyl alcohol, and water is a transparent jelly-like product that does not stick to the hands, stretches like chewing gum when stretched loosely, and easily breaks when pulled hard. It is a thing.

As described above, in the present invention, boric acid and/or borax can be used to produce the gel-like material, but it is particularly preferable to use boric acid to produce the gel-like material.

The reason for this is that when borax is used, it produces a gel-like substance that is slightly lumpy and less sticky, whereas when boric acid is used, it produces a gel-like substance that is slightly lumpy and less sticky.
A gel-like material with extremely good elongation and easy processing is obtained, and when mixed with a base material for craft clay whose main ingredient is starchy material, it has plasticity that allows it to be easily torn by hand into the desired size. This is because it is possible to produce even better clay for construction.

Additionally, alcohol or the like may be added for the purpose of improving extensibility, etc., if necessary during the production of the gel-like material.

Next, the gel-like material prepared above is mixed with a construction clay base material whose main raw material is a starchy material, and kneaded to produce construction clay.

In this case, starchy materials include grain flours such as wheat flour, rice flour, buckwheat flour, and rye flour; starches such as corn starch, potato starch, wheat starch, sweet potato starch, and charasaba starch;
Products made of flour such as white bread can be used.

As the starchy material, only type 111 may be used, or a plurality of types may be used in combination. Among the starchy materials mentioned above, potato starch, corn starch, wheat flour and rice flour are preferred in terms of extensibility and processability.

Furthermore, as the starch material, both non-σ and gelatinized starch materials can be used, and furthermore, gelatinized and non-gelatinized starch materials may be used in combination. When a pregelatinized clay and a non-pregelatinized clay are used together, a clay for construction that dries quickly and is suitable as clay for crafts can be obtained.

The above-mentioned "craft clay base material whose main raw material is starchy material" (hereinafter referred to as "starchy craft clay base material") is mixed with a gel-like substance to produce clay for construction. , (1
It is preferable to use either a) starchy material itself, or (2) a combination of starchy material and synthetic resin.

Starchy Crafting Clay When producing crafting clay using the starchy material itself as a base material, the starchy material 10
About 1 to 100 parts of gel-like material to 0 parts, especially about 2 to I
It is preferable to mix and knead at a ratio of O part. Mixing and cross-talk between the two is normally 15-60'C! It can be done at a temperature of
In particular, from the viewpoint of preventing deterioration of starchy materials, the temperature is about 30 to 40℃.
It is best to mix and knead with a . As a result of such mixing and kneading of the above-mentioned gel-like material and starch material, there is no discoloration (9@ change) for a long period of time, and no undesirable sigmaization of starch occurs during kneading, and there is no stickiness, tactility, and moldability. An excellent working clay with good properties such as elasticity and viscoelasticity is produced.

In addition, when using a combination of starch material and synthetic resin as a starch clay base material, synthetic resins such as polyvinyl acetate, polyvinyl chloride, and poly(meth)acrylate may be used in the form of an emulsion. It is preferable to use such a synthetic resin emulsion in combination with a starchy material together with a small amount of polyvinyl alcohol powder prepared separately from the one for producing the gel-like material. As a synthetic resin emulsion, the synthetic resin solid content concentration in the emulsion is about 1 to 3.
It is preferable to use 5% by weight, and polyvinyl acetate emulsion is particularly preferred among synthetic resin emulsions.

In this case, about 10 to 50 parts of synthetic resin and about 0.0 parts of polyvinyl alcohol powder are added to 100 parts of gel-like material.
It is preferable to mix in a proportion of 1 to 10 parts.

Mixing and kneading of the gel-like material, starch material, synthetic resin emulsion and polyvinyl alcohol powder are carried out in the same manner as above.
It is usually carried out at a temperature of 15-60°C, preferably about 30-40°C.

As a result of such mixing and kneading, there is no discoloration (browning) over a long period of time, no undesirable gelatinization of the flour during kneading, and good properties in terms of stickiness, texture, viscoelasticity, etc. Crafting clay with excellent shrinkage properties is produced.

Furthermore, in the present invention, when manufacturing clay by mixing the gel-like material and the starchy clay base material, in addition to the above components, aluminum sulfate, potassium sulfate, sodium sulfate, sodium chloride, Salting-out astringents with low toxicity such as light deposition;
Plasticizers (@ warm lubricants) such as glycerin, propylene glycol, paraffin, sorbitol, vegetable oil, mineral oil, lecithin, glycerin fatty acid ester, sucrose fatty acid ester, propylene glycol, dibutyl phthalate; talc, clay, diatomaceous earth, fired china clay, Fillers such as silica and alumina; emulsifiers such as sorbitan fatty acid ester, carboxymethylcellulose, and propylene glycol fatty acid ester; coloring agents such as food additives; antioxidants, etc. can be added as needed, and clay for construction It is possible to make the characteristics even better. In particular, when manufacturing clay by mixing and kneading the above boric acid/borax gel with a starchy clay base material consisting of a starchy material, a synthetic resin emulsion, and a polyvinyl alcohol powder, a salting-out astringent, When emulsifiers, plasticizers, etc. are added, a clay for construction with better properties such as color fastness, adhesion, texture, moldability, and viscoelasticity is produced.

〔Effect of the invention〕

In the present invention, a gel-like material is prepared in advance from boric acid and/or borax and polyvinyl alcohol, and this gel-like material is mixed with a craft clay base material whose main raw material is a starchy material to produce construction clay. By doing this, compared to manufacturing clay without preparing the gel-like material in advance, it is superior in adhesiveness, feel, moldability, and viscoelasticity, and the color tone does not change color (browning) over a long period of time. As a result, it is possible to produce works with a desired color and no discoloration, and such discoloration resistance is achieved by using wheat flour as the main starchy material. This is especially noticeable when

Furthermore, in the present invention, good viscosity can be produced without strictly controlling and adjusting the temperature so that the temperature during clay production is always kept at 60° C. or lower.

The present invention will be specifically explained below by giving examples, but the present invention is not limited by these examples.

Example 1 and Comparative Example 1 14 g of polyvinyl alcohol (hereinafter referred to as rPVAJ) (degree of polymerization 500 to 2500) and 43 g of water were mixed,
This mixture was stirred at a temperature of about 75-80°C for 30 minutes to prepare a PVA aqueous solution.

Separately, prepare a boric acid aqueous solution by dissolving 4.5 g of boric acid in 38.5 g of boiling water at about 75°C, and add this boric acid aqueous solution to the above-mentioned PV.
A 1i21 acid gel was prepared by adding the solution to the A aqueous solution while maintaining the temperature at about 70 to 80°C and stirring for 5 minutes.

48g cornstarch, 2.3g pregelatinized flour,, P
A mixed powder was prepared by mixing 0.3 g of VA powder (degree of polymerization 500-2500) and 0.3 g of aluminum sulfate (salting-out astringent) at room temperature. This mixed powder was put into a kneader-type mixing/kneading machine (manufactured by Bengami Seisakusho), and 35% of the polyvinyl acetate aqueous solution (polyvinyl acetate content: 2.8% by weight) was added to it.
g, span■ (emulsifier) 0.5g, propylene glycol (plasticizer) 3g and water 7.8g to make approximately 30~4
0'C! The mixture was stirred and mixed for 25 minutes at a temperature of , and then 2.8 g of the gel material prepared above was added thereto and kneaded for 25 minutes at room temperature to produce a clay for construction (A-1) (Example 1).

Separately, without preparing the gel-like material in advance.

The same types and amounts of ingredients as used in Example 1 were put into the same mixing/kneading machine as above and kneaded at about 30 to 40°C for 25 minutes to produce clay for construction (A-2). (Comparative example 1
).

Various properties of the construction clays A-1 and A-2 prepared above were investigated.

First, for the measurement of discoloration, manufactured clay A
-1 and A-2 were left at room temperature to determine the number of days until they changed color.

In addition, tackiness, feel, moldability, and viscoelasticity were evaluated by five panelists according to the following criteria, and the average value was rounded off.

Adhesion criteria 3. Craft clay does not stick to hands and craft sticks.

2... Crafting clay slightly adheres to hands and crafting sticks.

1... Crafting clay adheres to hands and crafting sticks, making it impossible to craft.

Criteria for tactile sensation 4... Craft clay has a fine texture and soft texture.

3. The texture of the clay for construction is a little rough and the texture is a little hard.

2...The fine texture of the craft clay is sticky.

1... Craft clay has a rough texture and a hard feel.

Criterion 4 for moldability: When several small lumps of construction clay are collected and kneaded, they come together very well.

3. When you collect a few small lumps of craft clay and knead them, they come together well, but are a little soft.

2...When I gathered a few small lumps of craft clay and kneaded them, they didn't come together well and were too soft.

l... When I collect a few small lumps of craft clay and knead them, they don't come together easily.

Measurement of viscoelasticity 3: When approximately 50g of clay was rolled up and stretched with both hands, it collapsed after being stretched appropriately.

2. When I rolled up about 50g of clay and stretched it out with both hands, it stretched out so long that it was difficult to break it.

Engineering: When I rolled up about 50g of clay and then stretched it out with both hands, it barely stretched and broke.

The results obtained above are shown in Table 1 below.

[Table 1] Example A-L A-
2. Discoloration No discoloration after 2 months Browning and tackiness after 2 months 31. Touch 42. Moldability 41. Viscoelasticity 31 From the results in Table 1 above, a gel-like material was made in advance from polyvinyl alcohol and boric acid, and then starch was prepared. In Embodiment 1 of the present invention, in which clay for construction is produced by mixing with a quality material,
Compared to Comparative Example 1, in which construction clay was manufactured by mixing all the components without producing a gel-like material in advance, the resulting construction clay exhibited extremely little browning over time, and had a high adhesiveness. It can be seen that the texture, moldability, and viscoelasticity are also excellent.

Example 2 and Comparative Example 2 A gel-like material was prepared in advance from boric acid and polyvinyl alcohol in the same manner as in Example 1.

This 1il! 3g acid gel and 100g cornstarch
into the same mixing/kneading machine used in Example 1,
Mix and knead for 25 minutes at about 30 to 40℃ to make craft clay (
B-1) was produced (Example 2).

On the other hand, PVA, boric acid, corn starch, and water were simultaneously added in the same amounts as in Example 2 directly into the mixer/mixer, mixed and kneaded for 25 minutes at about 30 to 40°C, and then the clay for construction (B -2) was produced (Comparative Example 2).

The quality of the construction clays B-1 and B-2 produced above was examined in the same manner as in Example 1 and Comparative Example 1.

The results are shown in Table 2 below.

[Table 2] Example B-1 Discoloration No discoloration after 2 months Adhesion 3 Touch 3 Moldability 4-2 Browning after 2 months Example 3 and Comparative Example 3 In the same manner as in Example 1, with boric acid and A gel-like material was prepared in advance from polyvinyl alcohol.

34g of wheat flour 3.5g of pregelatinized potato starch and PVA
A mixed powder was prepared by mixing 0.2 g of powder (!! degree of about 500 to 2500) at room temperature. This mixed powder was put into the same mixing/kneading machine used in Example 1, and a polyvinyl acetate aqueous solution (polyvinyl acetate content 28% by weight) was added to the mixer.
Add 30.3 g of gel and mix with stirring for 25 minutes at a temperature of about 30 to 40°C, and then add the gel material 32 prepared above.
g and kneaded for 25 minutes at room temperature to form construction clay (C-1).
) was produced (Example 3).

Separately, without preparing the gel-like material in advance, Example 3
The same types and amounts of ingredients as those used in were put into the same mixer and mixer as above and kneaded for 25 minutes at about 30 to 40°C to produce construction clay (C-2) (Comparative Example 3).

The quality of the construction clays C-1 and C-2 produced above was examined in the same manner as in Example 1 and Comparative Example 1.

The results are shown in Table 3 below.

example Discoloration sticky sense of touch Formability Viscoelasticity [Table 3] -1 No discoloration after 2 months -2 Browning after 2 months

Claims (1)

[Claims] Preparing a gel-like material in advance by mixing boric acid and/or borax with polyvinyl alcohol in the presence of water, and mixing this gel-like material into a clay base material for crafts whose main raw material is starchy material. A method for manufacturing clay for construction, characterized by: