JP2002356365A - Lightweight clay and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lightweight clay and a method of manufacturing it, which is easy to mould into a predetermined form, while having a moderate light weightiness and preservability, and is low in manufacturing cost. SOLUTION: A mean grain diameter of an organic hollow minute ball is set at a value within the range of 30-150 μm, and an adding amount thereof is set at a value within the range of <0.1-3 wt.% of total amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight clay and a method for producing the same, and more particularly, to a lightweight clay having an appropriate lightness and formability, excellent storage stability (expandability), and low production cost. And its manufacturing method.

[0002]

2. Description of the Related Art Conventionally, clay used in arts and crafts and school teaching materials is mainly made of granular materials or disintegrated plant bodies.
In many cases, the main material is formed by adding additives such as a binder, a fragrance, a pigment, moisture, and an oil for binding the granular material. Therefore, there was a problem that the conventional clay was heavy and inconvenient to use. For that reason,
No. 893 discloses a lightweight clay composed mainly of powdered styrene foam and added with pulp material, water and the like. However, the powdered polystyrene foam has a large number of voids on the surface due to its structure, and water or the like penetrates into these voids, so that it becomes rich in water or liquid. For this reason, there remains a problem in weight reduction that the weight of the entire lightweight clay is not reduced so much. In addition, there was also a manufacturing problem that it was not easy to miniaturize the polystyrene foam and it was difficult to uniformly mix the polystyrene with the compounding material.

[0003] Japanese Patent Publication No. 59-50615 discloses that 30 to 40 micro hollow particles made of a foamed inorganic material having a particle size of less than 150 µm and a bulk specific gravity of 0.6 or less.
Weight% and fiber powder having a fiber length of 10 mm or less
3% by weight and a talc powder having a particle size of 150 μm or less
60% by weight, 3 to 8% by weight of a water-soluble synthetic paste alone or in combination and water are kneaded, and the penetration is 100%.
A glazing molding clay adjusted to ~ 350 is disclosed, and a sculpture material having a similar configuration is disclosed in
No. 7-16356. However, such molding clays and sculptures are difficult to mix and disperse due to the large amount of fine hollow particles and rock powder made of expanded inorganic material, and the obtained molding clays and sculptures are However, there was a problem that the handling and the formability were poor and the manufacturing cost was high.

Japanese Patent Application Laid-Open No. 2-123390 discloses that organic hollow microspheres whose outer shell is made of a copolymer containing acrylonitrile or vinylidene chloride are contained in an amount of 3 to 20% by weight, based on the total amount, of a synthetic binder. (Carboxymethylcellulose) 5-20% by weight, fiber powder 10-30% by weight,
A lightweight clay that is lightweight, has high whiteness, and can be easily incinerated by mixing water at a ratio of 50 to 60% by weight has been proposed. That is, for example, if the blending ratio of the organic hollow microspheres is less than 3% by weight, a predetermined target weight cannot be achieved. This is because the property as is impaired. Further, when the blending ratio of the fiber powder is less than 10% by weight, the function as a binder becomes insufficient. On the other hand, when the blending ratio of the fiber powder exceeds 30% by weight, a large amount of water is stored. This is because the weight reduction is impaired. Further, if the mixing ratio of water is less than 50% by weight, the molding operation becomes difficult. On the other hand, the mixing ratio of water is 60% by weight.
If it exceeds 3, softening will result in poor formability, and furthermore, weight reduction will be impaired. However, such lightweight clay is not easy to mix and disperse the organic hollow microspheres because of the large amount of the organic hollow microspheres added, and the obtained lightweight clay is excessively lightweight, and is difficult to handle and form. However, there was a problem that the production cost was high. In addition, since such lightweight clay has a large amount of organic hollow microspheres to be added, there is a problem that so-called unfoamed organic hollow microspheres in which a foaming gas (foaming liquid) remains remain. It was observed. Therefore, when the lightweight clay is covered with a packaging material such as polyethylene film and stored for a long time, or when the ambient temperature rises in summer, etc.,
In the case of high temperature, due to the residual foaming gas,
There was a problem that the lightweight clay covered with the packaging material expanded to about 1.2 to 3 times the volume of the original clay (hereinafter referred to as expansion problem). Furthermore, in such a lightweight clay, since the amount of the organic hollow microspheres to be added is large, when a pigment is added, there is also a problem that the dispersibility of the pigment is inhibited, and excellent color developability cannot be obtained. .

Japanese Patent Application Laid-Open No. 10-268755 discloses glass micro hollow spheres 30 to 70 having a particle size of 1 to 200 μm.
Parts by weight, 30 to 60 parts by weight of fiber powder, 10 to 50 parts by weight of carboxymethyl cellulose, and 200 to 400 parts by weight of water (based on the total amount of glass micro hollow spheres, fiber powder, and carboxymethyl cellulose). By doing so, a lightweight clay having a small number of dry days and a small shrinkage rate is disclosed. That is, for example, if the mixing ratio of the glass micro hollow spheres is less than 30 parts by weight, it is not possible to achieve a predetermined weight reduction, while if the mixing ratio of such glass micro hollow spheres exceeds 70 parts by weight,
This is because shrinkage and cracking in the lightweight clay are increased. Further, when the blending ratio of the fiber powder is less than 30 parts by weight, the shrinkage and cracking in the lightweight clay become large. On the other hand, when the blending ratio of the fiber powder exceeds 60 parts by weight, a large amount of water is stored. This is because weight reduction is impaired. Further, when the mixing ratio of the water is less than 200 parts by weight, it is difficult to perform the molding operation on the lightweight clay. On the other hand, when the mixing ratio of the water exceeds 400 parts by weight, the water softens and the molding property is poor. And furthermore, it is easy to adhere to hands. However, such a lightweight clay has a problem in that the proportion of glass micro hollow spheres or fiber powder added is too large, so that the moldability is poor and the production cost is high. In addition, since such lightweight clay has a large amount of added glass organic hollow microspheres, when a pigment is added, there is also a problem that the dispersibility of the pigment is inhibited, and excellent color-forming properties cannot be obtained. .

[0006]

SUMMARY OF THE INVENTION The inventors of the present invention
The average particle size and the amount of organic hollow microspheres in lightweight clay are examined to the extent that problems have been considered to occur in the past.
Or they found that it affected the expansion problem.
In other words, the present invention is excellent in moldability and lightness, and has a problem of expansion even when it is covered with a packaging material and stored for a long period of time, or when the ambient temperature rises and becomes high temperature in summer or the like. It is an object of the present invention to provide a lightweight clay which can provide excellent storage properties by eliminating the above problems and which is inexpensive to produce, and a method for producing the same.

[0007]

According to the present invention, in a lightweight clay containing organic hollow microspheres, the average particle size of the organic hollow microspheres is set to a value within the range of 30 to 150 μm, and A lightweight clay characterized in that the amount of added microspheres is a value within the range of 0.1 to less than 3% by weight based on the total amount is provided, and the above-mentioned problems can be solved. That is, by considering both the average particle size and the addition amount of the organic hollow microspheres in this way, even if the addition amount of the organic hollow microspheres, which has conventionally been considered to cause a problem, is sufficient and moderate. In addition to achieving a light weight, it is possible to obtain a lightweight clay excellent in formability. Also, since the amount of organic hollow microspheres to be added can be reduced, not only the mixing and dispersion of lightweight clay becomes easy, but also the abundance of unfoamed organic hollow microspheres is reduced, and moreover, expensive organic hollow microspheres are reduced. Since the amount used can be reduced, excellent storage properties (expandability) can be obtained, and production costs can be kept low. Furthermore, because the addition amount of the organic hollow microspheres is small, even when a dye is added for colorization, excellent color developability can be obtained without inhibiting the dispersibility of the dye. .

In constituting the lightweight clay of the present invention, the organic hollow microspheres are preferably white. The organic hollow microspheres having a shell made of a vinylidene chloride-acrylonitrile copolymer and the like disclosed in JP-A-2-123390 and the like are ocher to brown in color, and thus, organic materials having a high whiteness are obtained. By using hollow microspheres,
It is possible to obtain a lightweight clay having more excellent coloring properties.

Further, in constituting the lightweight clay of the present invention, a hydroxyl group-containing compound and a carboxyl group-containing compound, or one of the polar compounds are further contained, and the amount of the polar compound added to the total amount is , 0.1 to 30% by weight. By using a polar compound in this way, a lightweight clay having more excellent formability and color development can be obtained.

[0010] Further, in constituting the lightweight clay of the present invention, fibers are further contained, and the amount of the fibers to be added is set to a value within a range of less than 1 to 10% by weight based on the total amount. preferable. By using the fibers in this way, a lightweight clay having more excellent formability and lightness can be obtained. In addition, as described above, conventionally, when the amount of added fiber is less than 10% by weight based on the total amount,
It was said that the function as a binder was insufficient,
By taking into account both the average particle size and the amount of organic hollow microspheres, the restriction on the amount of such fibers can be greatly relaxed.

In constituting the lightweight clay of the present invention, water is further contained, and the amount of the water added is
It is preferable to set the value in the range of 65 to 85% by weight based on the total amount. By using water in this way,
It is possible to obtain a lightweight clay having more excellent formability and coloring. As described above, conventionally, the amount of water added is
It is said that if the content exceeds 60% by weight based on the total amount, the composition softens, the formability becomes poor, and the weight reduction is impaired. By taking this into account, the restriction on the amount of water to be added can be greatly eased.

In constituting the lightweight clay of the present invention, a pigment is further contained, and the amount of the pigment to be added is within a range of 0.1 to 10% by weight based on the total amount. Is preferred. When a pigment is added in this manner, coloration can be easily performed, and a lightweight clay excellent in coloring property can be obtained.

Further, in constituting the lightweight clay of the present invention, inorganic hollow microspheres are further contained, and the amount of the inorganic hollow microspheres added is 0.01 to 0.01 with respect to the total amount.
It is preferable to set the value in the range of 10% by weight. By adding inorganic hollow microspheres in addition to organic hollow microspheres in this way, lightweight clay with even better shapeability and lightness can be obtained, and expansion problems caused by unfoamed organic hollow microspheres And the problem of reduced color developability can be effectively reduced.

According to another aspect of the present invention, there is provided a method for producing a lightweight clay containing organic hollow microspheres, wherein the organic hollow microspheres having an average particle size in a range of 30 to 150 μm are used. While using, the organic hollow microspheres are kneaded using a kneader, and the amount added, with respect to the total amount,
A method for producing a lightweight clay, characterized in that the value is within a range of 0.1 to less than 3% by weight. When implemented in this way, it is possible to efficiently obtain an inexpensive lightweight clay while being excellent in formability and lightness.

[0015]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention is a lightweight clay containing organic hollow microspheres, a polar compound, fibers, water, and a pigment, wherein the average particle size of the organic hollow microspheres is Lightweight clay having a diameter in the range of 30 to 150 μm and the amount of organic hollow microspheres in the range of 0.1 to less than 3% by weight based on the total amount, and a method for producing the same. It is. Hereinafter, the description will be made separately for constituent elements such as organic hollow microspheres and polar compounds.

1. Organic Hollow Microspheres (1) Type 1 The organic hollow microspheres can be suitably used as long as they have an outer shell (shell wall) made of an organic material and have voids therein. As such organic hollow microspheres, for example, the outer shell is made of vinylidene chloride-acrylonitrile copolymer resin, vinyl acetate-acrylonitrile copolymer resin, methyl methacrylate-acrylonitrile copolymer resin, acrylonitrile resin, etc. , And those containing gas or liquid are preferable. Among these organic hollow microspheres, in particular, organic hollow microspheres having an outer shell made of vinylidene chloride-acrylonitrile copolymer resin are easy to produce, but can be expanded to a desired size when heated. preferable. Also,
Organic hollow microspheres having an outer shell made of a vinyl acetate-acrylonitrile copolymer resin, a methyl methacrylate-acrylonitrile copolymer resin, an acrylonitrile resin, or the like are more preferable because of their high whiteness.

(2) Type 2 In addition to the organic hollow microspheres, it is also preferable to use inorganic hollow microspheres whose outer shell is made of an inorganic material, for example, a glass material. Such inorganic hollow microspheres are colorless and transparent and have high pressure resistance, for example, 750 psi (1 ps).
i = 6.90 × 10 ³ N, 1 kgf = 9.807 N / c
m ² ), the residual ratio when pressurized at the measurement pressure of 90 to 92
(VOL%) and is light.
Therefore, by using the organic hollow microspheres and the inorganic hollow microspheres together, the weight per unit volume of the lightweight clay can be remarkably reduced, and the organic hollow microspheres exist around the inorganic hollow microspheres. By doing so, the inorganic hollow microspheres can be effectively prevented from being destroyed and the dispersibility of the inorganic hollow microspheres can be further improved by serving as a cushion material. In addition, by using the organic hollow microspheres and the inorganic hollow microspheres in this way, in relation to the pigment, the coloring property is enhanced, the shape retention of the lightweight clay is increased, and the shrinkage rate is reduced. can do. Furthermore, the combined use of the organic hollow microspheres and the inorganic hollow microspheres as described above allows the use amount of the organic hollow microspheres to be relatively reduced. The expansion problem can be effectively prevented, and more excellent storability can be obtained.

However, even when the organic hollow microspheres and the inorganic hollow microspheres are used in combination, the amount of the organic hollow microspheres to be added is within a range of less than 3% by weight based on the total amount. There is a need to. That is, the addition amount of the organic hollow microspheres is 3
When the content is more than 10% by weight, the abundance of the unfoamed organic hollow microspheres rapidly increases, so that it is difficult to prevent the expansion problem caused by the unfoamed organic hollow microspheres, or in relation to the pigment, This is because the coloring property is reduced.

(3) Whiteness It is preferable that the color of the organic hollow microspheres is white or a color similar thereto. As mentioned above,
The organic hollow microspheres having an outer shell made of a vinylidene chloride-acrylonitrile copolymer or the like disclosed in JP-A-123390 and the like usually have a color of ocher to brown, and as described above, an organic material rich in whiteness is used. By using hollow microspheres, it is possible to obtain a lightweight clay having more excellent coloring properties. In addition, the color of the organic hollow microspheres can be compared with a color sample, and can be determined visually or using a microscope,
Visual luminosity (L value) measured by a reflectometer may be used as a relative reference. That is, regarding the color of the organic hollow microspheres, a reflectometer (for example, TR-10 manufactured by Tokyo Denshoku Co., Ltd.)
(00D type) is preferably set to a value of 50 or more. The reason is that such visual luminosity is 50
When the value is less than 1, the organic hollow microspheres have a brownish color, and when added to a lightweight clay together with a pigment, particularly a white pigment or a yellow pigment, it becomes turbid, and the color developability may be significantly reduced. It is. However, if the value of the luminosity is too high, the constituent materials of the organic hollow microspheres may be excessively limited. Therefore, such visual luminosity is 7
The value is preferably in the range of 0 to 99,
More preferably, the value is in the range of 5. It should be noted that such adjustment of visual luminosity can be easily achieved by adding white particles such as titanium oxide or silica to the outer shell of the organic hollow microspheres, or by coating the periphery with these white particles. Can be. Reducing the amount of vinyl chloride resin, vinylidene chloride resin, or formaldehyde resin (phenol resin, melamine resin, guanamine resin, urea resin) or the like in the outer shell of the organic hollow microsphere;
Specifically, it can be easily achieved by setting the value to 10% by weight or less.

(4) Average Particle Size 1 The average particle size of the hollow organic microspheres is set to a value within the range of 30 to 150 μm. The reason for this is that when the average particle diameter of the organic hollow microspheres is less than 30 μm, the formability of the lightweight clay may be reduced, or it may be difficult to reduce the weight when a predetermined amount is added. is there. On the other hand, if the average particle diameter of the organic hollow microspheres exceeds 150 μm, mixing and dispersion may become difficult, or the formability of the lightweight clay may decrease. Therefore, the average particle diameter of the organic hollow microspheres is more preferably set to a value in the range of 50 to 130 μm, and further preferably to a value in the range of 70 to 120 μm. Note that the average particle diameter of the organic hollow microspheres can be calculated using an image processing apparatus, by capturing an image of the organic hollow microspheres with an optical microscope and then using the image.

(5) Average particle size 2 In determining the average particle size of the organic hollow microspheres,
It is preferable to consider the average particle size of the dye described below. That is, when the average particle size of the dye is D1 and the average particle size of the organic hollow microspheres is D2, the ratio of D2 / D1 is 10
It is preferable that the value be in the range of ５０50,000. The reason for this is that if the ratio of D2 / D1 is less than 10, the pigment is not uniformly dispersed, and the organic hollow microspheres may hinder color development. Meanwhile, such D2
When the ratio of / D1 exceeds 50,000, the dye is likely to be aggregated, and may not be uniformly dispersed, so that the coloring property may be reduced. Therefore, in order to improve the coloring property of the dye, the D2 / D1
Is more preferably in the range of 50 to 10,000, and even more preferably in the range of 100 to 1,000.

(6) Addition amount The addition amount of the organic hollow microspheres is
It is necessary to set the value within the range of 0.1 to less than 3% by weight. The reason is that if the amount of the organic hollow microspheres is less than 0.1% by weight, it is difficult to reduce the weight of the lightweight clay. On the other hand, when the addition amount of the organic hollow microspheres is 3% by weight or more, the formability and handling of the lightweight clay are remarkably reduced, and the amount of the remaining unfoamed organic hollow microspheres is increased, and the lightweight clay is coated with a packaging material. This is because, when stored for a long period of time, or when the ambient temperature rises in summer or the like, the packaging material expands, and the storage properties are significantly reduced. Also,
The reason is that organic hollow microspheres are extremely expensive, so that if the added amount is 3% by weight or more, the cost of the obtained lightweight clay becomes extremely expensive. Therefore, since the balance between the formability and expansibility of the lightweight clay and the lightness is better, the amount of the organic hollow microspheres to be added is set to a value within the range of 0.5 to 2.9% by weight. Are more preferable, and 1-2.
More preferably, the value is in the range of 5% by weight.

Here, with reference to FIGS. 1 and 2, the relationship between the amount of the organic hollow microspheres added, the lightness and the formability of the lightweight clay, and the relationship with the expandability will be described in detail. FIG. 1 is a numerical representation of the data of lightness and formability in Table 1, with 5 points for ◎, 3 points for ○, 1 point for Δ, and 0 points for ×. Was calculated. The horizontal axis in FIG. 1 shows the addition amount (% by weight) of the organic hollow microspheres, and the left vertical axis shows the lightness (relative value). Curve A shows the relationship. Is shown. On the other hand, the right vertical axis in FIG. 1 shows the formability (relative value).
, Respectively, and the curve B shows the relationship with the added amount (% by weight) of the organic hollow microspheres. As can be understood from FIG. 1, as the amount of the organic hollow microspheres is increased, the evaluation of the lightness of the lightweight clay is improved, but the evaluation of the formability is not more than 3% by weight.
Extremely low. Therefore, by setting the addition amount of the organic hollow microspheres to a value within the range of 0.1 to less than 3% by weight, it is possible to achieve an excellent balance between the lightness of the lightweight clay and the moldability, It can be understood that by setting the addition amount of the organic hollow microspheres to a value within the range of 1 to 2.5 weight, a further excellent balance can be obtained between these properties. FIG. 2 is a numerical representation of the expandability data of Table 1, with 5 points for ◎, 3 points for ○, 1 point for Δ, and 0 points for ×. Numerical values were calculated. The horizontal axis in FIG. 2 shows the addition amount (% by weight) of the organic hollow microspheres, and the left vertical axis shows the expandability (relative value). As can be understood from FIG. 2, as the amount of the organic hollow microspheres increases, the evaluation result of the swelling property decreases, that is, the storability decreases. Therefore, by setting the addition amount of the organic hollow microspheres to a value within the range of 0.1 to less than 3% by weight, not only the lightness and formability of the lightweight clay, but also
It can be understood that the problem of expansion during storage can be effectively reduced and the characteristics can be improved.

(7) Bulk density The bulk density of the hollow organic microspheres is 0.001 to 0.5 g.
/ Cm ³ is preferable. The reason is that the bulk density of such organic hollow microspheres is 0.001 g / c.
If the value is less than m ^3, it may be difficult to uniformly mix and disperse the compound in the lightweight clay. On the other hand, if the bulk density of such organic hollow microspheres exceeds 0.5 g / cm ³ , the ductility of the lightweight clay may be reduced or the weight may be difficult to reduce. Therefore, the bulk density of the organic hollow microspheres is more preferably set to a value within the range of 0.005 to 0.2 g / cm ³ , and 0.01 to 0.1 g / cm ^3.
More preferably, the value is in the range of g / cm ³ .
The bulk density of such organic hollow microspheres is determined according to JIS K
It can be measured according to 5101 (pigment test method).

(8) pH value It is preferable that the pH value of the organic hollow microspheres is a value within the range of 3 to 11. The reason for this is that if the pH value of the organic hollow microspheres becomes less than 3, the hydroxyl group-containing compound or the carboxyl group-containing compound may be added, and the organic hollow microspheres may gel when stored for a long period of time. On the other hand, when the pH value of such organic hollow microspheres exceeds 11, mixing and dispersion and handling may become difficult. Therefore, the pH value of the organic hollow microspheres is 6-1 to 1.
Preferably, the pH value is within the range of 0.5, and the pH value is 7
It is further preferable to set the value to a value within a range from neutral to weakly alkaline to 10.5.

2. Polar Compound (1) Type The polar compound is preferably a hydroxyl group-containing compound or a carboxyl group-containing compound. In addition, like polyacrylic acid and polyvinyl alcohol,
Although there are compounds containing both a hydroxyl group and a carboxyl group, they are separately described for convenience.

Hydroxyl-containing compound Examples of the hydroxyl-containing compound include polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyethylene vinyl acetate, urea resin, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose and the like. This is because the addition of such a hydroxyl group-containing compound facilitates the adjustment of the malleability and creep resistance of the lightweight clay. Further, since these hydroxyl group-containing compounds are usually water-soluble, excellent compatibility can be obtained even when water is added to lightweight clay. In particular,
Polyvinyl alcohol has a large amount of hydroxyl groups per unit weight, and therefore, by adding a relatively small amount,
Since the malleability and handleability of the lightweight clay can be effectively improved, it is a more preferable hydroxyl group-containing compound. Also, polyvinyl formal and polyvinyl butyral are resins obtained by acetalizing polyvinyl alcohol with formaldehyde and butyraldehyde, respectively.
It is effective when used when obtaining heat resistance. further,
Polyvinyl acetate is a raw material before polyvinyl alcohol is saponified, but is an effective hydroxyl group-containing compound when it is desired to obtain a lighter clay having better malleability.

Carboxyl Group-Containing Compound Examples of the carboxyl group-containing compound include carboxymethyl cellulose (CMC), acrylic acid, polyvinyl acetate and the like. Here, when carboxymethylcellulose is used, carboxymethylcellulose having a degree of etherification within a range of 0.1 to 2 is preferable.
The reason for this is that if the degree of etherification of carboxymethyl cellulose is less than 0.1, the lightweight clay becomes sticky and handling may be difficult. On the other hand, when the degree of etherification of carboxymethyl cellulose exceeds 2, the ductility of the lightweight clay is reduced, and it may be difficult to form a thin film.

(2) Addition amount The addition amount of the polar compound is adjusted to the total amount (10%) of the lightweight clay.
0% by weight) is preferably in the range of 0.1 to 30% by weight. The reason for this is that if the amount of the polar compound is less than 0.1% by weight, the handling properties and moldability of the lightweight clay may be significantly reduced. On the other hand, if the amount of the polar compound exceeds 30% by weight, the malleability of the lightweight clay may be reduced or the mixing and dispersion may be difficult. Therefore,
Since the balance between the handleability and moldability of the lightweight clay and the malleability of the lightweight clay is better, the amount of the polar compound to be added is set to 0.1 to the total amount (100% by weight) of the lightweight clay.
Preferably, the value is in the range of 5 to 20% by weight.
More preferably, the value is in the range of 15 to 15% by weight.
More preferably, the value is in the range of 2 to 10% by weight.

3. Fiber (1) Type The type of fiber (pulp) as an additive is not particularly limited, and for example, it is preferable to use hardwood and softwood as raw materials. However, it can be said that it is more preferable to use fibers made of hardwood. The reason for this is that fibers made from hardwood are usually shorter and averaged in length than fibers made from softwood, and can be easily dispersed when making lightweight clay. .

(2) Average Fiber Length The average fiber length of the fibers is preferably set to a value within the range of 0.01 to 20 mm. The reason for this is that if the average fiber length of such fibers is less than 0.01 mm, the ductility of the lightweight clay may be reduced, or it may be difficult to reduce the weight. On the other hand, the average fiber length of such fibers is 2
If the thickness exceeds 0 mm, it may be difficult to uniformly mix and disperse the compound in the lightweight clay. Therefore,
Since the balance between the spreadability of the lightweight clay and the mixing and dispersibility becomes better, the average fiber length of the fibers is 0.1 to 10 m.
m is more preferably in the range of 0.5 to 5
More preferably, the value is in the range of mm.

(3) Amount of Addition The amount of the fiber to be added is preferably determined in consideration of the handleability and moldability of the lightweight clay, or the ease of manufacturing the lightweight clay. For example, it is preferable to set the value within a range of 1 to less than 10% by weight based on the total amount. The reason for this is that when the amount of such fiber is less than 1% by weight,
This is because the effect of addition may not be exhibited. On the other hand, if the amount of the fiber is 10% by weight or more, it may be difficult to control and manufacture the ductility of the lightweight clay. Therefore, it is more preferable that the amount of the fiber added is in the range of 2 to 9% by weight based on the total amount, and it is further preferable that the amount is in the range of 3 to 8% by weight.

4. Water Water is preferably determined in consideration of the handleability and moldability of the lightweight clay or the ease of manufacturing the lightweight clay. For example, it is preferable to set a value within a range of 65 to 85% by weight based on the total amount. The reason for this is that when the amount of water added is less than 65% by weight, the effect of addition is not exhibited,
This is because adjustment of the lightweight clay may be difficult. On the other hand, if the amount of water exceeds 85% by weight, it may be difficult to control the malleability and creep resistance of the lightweight clay. Therefore, it is more preferable that the amount of water to be added is set to a value within the range of 66 to 83% by weight, and more preferably to a value within the range of 67 to 80% by weight based on the total amount.

5. Dye (1) Kind The kind of the dye is not particularly limited, but may be any one which has been conventionally used in the field of ink, paint, etc., for example, an organic pigment, an inorganic pigment, or a dye. Is mentioned. As such an organic pigment,
Azo lakes, azo pigments such as insoluble azo pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, polycyclic rings such as thioindigo pigments, isoindolinone pigments, quinophthalone pigments Formula pigments, dye lakes and the like. Examples of the inorganic pigment include oxides such as titanium oxide, red iron oxide, chromium oxide, and iron black, cadmium yellow, chrome vermillion, navy blue, ultramarine blue, carbon black, yellow iron oxide, and pearl pigment. Furthermore, when more vivid colors are required, plastic type organic pigments based on formalin condensed resin, acrylic resin, guanamine resin, etc., and zinc sulfide, zinc silicate, zinc cadmium sulfide, etc. were sintered. It is also preferable to use an inorganic pigment or the like.

(2) Average Particle Size The average particle size of the dye is preferably set to a value within the range of 0.01 to 0.2 μm. The reason for this is that when the average particle size of the pigment is less than 0.01 μm, it becomes extremely easy to aggregate, it becomes difficult to uniformly disperse and disperse the pigment in lightweight clay, and the coloring property may decrease. It is. On the other hand, when the average particle size of the pigment exceeds 0.2 μm, a synergistic effect with the organic hollow microspheres is not exerted, and the coloring property of the lightweight clay is reduced. Therefore, since the balance between the cohesiveness of the dye and the color forming property is better, the average particle size of the dye is more preferably set to a value within the range of 0.06 to 0.18 μm, and more preferably 0.07 to 0 μm. .12μ
More preferably, the value is within the range of m.

(3) Particle size distribution 1 Regarding the particle size distribution of the pigment, the standard deviation is 0.05 μm.
The following values are preferred. The reason for this is that if the standard deviation of such a dye exceeds 0.05 μm, the light scattering becomes large or the particles are easily aggregated, so that the coloring property of the dye may be reduced. However, if the standard deviation of such a dye is excessively small, the production cost may increase due to control.
Therefore, since the balance between the coloring property of the dye and the production cost is better, the standard deviation in the particle size distribution of the dye is more preferably set to a value in the range of 0.04 to 0.01 μm, and 0.03 to 0.01 μm. More preferably, the value is in the range of 0.01 μm to 0.01 μm. The standard deviation in the particle size distribution of the dye can be measured, for example, using a laser type particle counter.

(4) Particle Size Distribution 2 Further, it is preferable that 95% of the particle size of the dye exists within a range of ± 10% of the average particle size. The reason for this is that by using a pigment having such a narrow particle size distribution, it is possible to obtain a lightweight clay having excellent color developability and formability. Conversely, the particle size of the pigment is 95%.
If the% is more than ± 10% of the average particle size, the dye is likely to aggregate, and it may be difficult to exhibit a synergistic relationship with the organic hollow microspheres. Therefore, if the particle size distribution of the dye is widened, the coloring property of the dye may be reduced. Therefore, in order to obtain a better coloring property with a dye, it is necessary to use 95% of the particle size of the dye.
Is more preferably in the range of ± 8% of the average particle size, and even more preferably in the range of ± 5% of the average particle size. The 95% particle size distribution in the average particle size of the dye can be measured, for example, using a laser type particle counter.

(5) Addition amount The addition amount of the dye is 0.1 to 10 with respect to the total amount.
It is preferable to set the value in the range of% by weight. The reason for this is that when the amount of such a dye is less than 0.1% by weight,
This is because the coloring effect of the dye may be reduced without exhibiting the addition effect or the synergistic effect with the organic hollow microspheres. On the other hand, if the added amount of the dye exceeds 10% by weight, light scattering becomes large or cohesion is remarkably liable to occur, and conversely, coloring properties may be reduced. Therefore, since the coloring property by the dye becomes better, it is more preferable that the amount of the dye to be added is within a range of 0.2 to 8% by weight, and a value within a range of 0.3 to 7% by weight. More preferably,

(6) Water Dispersibility The dye is preferably water-dispersible (including alcohol-dispersible), that is, hydrophilic. The reason for this is that by using a pigment having such properties, even when the lightweight clay contains water or alcohol, the pigment can be obtained without aggregation and excellent color developability and formability can be obtained. Also, if the dye is water-dispersible, even if the dye is fine particles, it can be stored in water,
Furthermore, it can be blended while keeping the solution in a stored state.

In order to make the pigment water-dispersible as described above, it is preferable that the acid value of the resin constituting the pigment is in the range of 50 to 300. The reason for this is that if the acid value of such a resin is less than 50, the water dispersibility of the resulting dye may be significantly reduced, while if the acid value of such a resin exceeds 300, it is obtained. This is because the dye may be easily aggregated. Therefore, the balance between the water dispersibility of the obtained dye and the cohesion becomes better, so that the acid value of the resin constituting the dye is 70 to 250.
More preferably within the range of 90 to 200
It is more preferable to set the value within the range. The resin constituting the dye preferably has a hydrophilic group such as a carboxyl group, a sulfonic acid group and a hydroxyl group in the molecule in order to control the acid value within the above range. That is, it is preferable to use a styrene-maleic acid copolymer resin, a styrene-sulfonic acid copolymer resin, a styrene-acrylic acid copolymer resin, or the like.

Further, in order to make the dye water-dispersible, it is preferable that the emulsion is in the form of an emulsion containing a surfactant such as an anionic surfactant or a nonionic surfactant. Examples of such surfactants include sodium dodecylbenzenesulfonate, sodium lauryl sulfate, ammonium salts of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, Polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene alkylamides, and acetylated products thereof may be used alone or in combination of two or more.

6. Other additives In lightweight clay, as additives, in addition to the additives described above,
Fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, oils,
It is also preferable to add one kind of waxes, glycerin, a thickener, a plasticizer, a surfactant, an organic solvent, or a combination of two or more kinds.

7. Production method (1) Mixing step This is a step of uniformly mixing the compounding raw materials such as the organic hollow microspheres, the pigment, the polar compound, the fiber, and water. For example, it is preferable to use a propeller mixer, a kneader, a planetary mixer, a three-roll mill, a ball mill, or the like so that these compounding raw materials can be uniformly mixed and dispersed. In particular, the organic hollow microspheres are light and are easily broken during kneading, while dispersion is apt to occur. Therefore, using a kneader, the number of rotations is 10 to 1,000 rpm, and the time is 1 to 1.
It is preferable to extrude and knead under the conditions of 60 minutes, using a kneader at a rotation speed of 30 to 300 rpm for 1 hour.
It is more preferable to carry out extrusion kneading under the conditions of 0 to 30 minutes.

The pigment is also dispersed in water or alcohol to prepare a solution so that the pigment can be uniformly mixed and dispersed, and an alkaline agent or the like is added to the solution to prevent the solution from aggregating. Is preferably adjusted to a value of 7 or more, more preferably adjusted to a value in the range of 8 to 10, and more preferably adjusted to a value in the range of 8.5 to 10. preferable. Further, when mixing the compounding raw materials, it is preferable to maintain the temperature, for example, in the range of 30 to 70 ° C. The reason for this is that if the mixing temperature is lower than 30 ° C., the compounding raw materials may not be uniformly mixed. On the other hand, if the mixing temperature is higher than 70 ° C., the obtained lightweight clay loses elongation and becomes brittle. This is because there are cases. Therefore, it is more preferable to maintain the mixing temperature at the time of mixing the compounding raw materials at a temperature in the range of 35 to 60 ° C, and it is even more preferable to maintain the mixing temperature in the range of 40 to 55 ° C.

(2) Viscosity adjustment step This is a step of adjusting the viscosity of the lightweight clay. By adding water, alcohol, or an organic solvent, the viscosity of the lightweight clay is, for example, 1 × 10 ³ to 1 × 10 ⁹ mPa · s (25
(° C.). The reason for this is
The viscosity of such lightweight clay is 1 × 10 ³ mPa · s (25
If the viscosity of the lightweight clay exceeds 1 × 10 ⁹ mPa · s (25 ° C.), the viscosity becomes too high. The lightweight clay that has been grown loses its elasticity and becomes brittle,
Conversely, handleability may be reduced. Therefore, the viscosity of such lightweight clay is 1 × 10 ⁴ to 1 × 10 ⁸
The value is more preferably in the range of mPa · s (25 ° C.), and even more preferably in the range of 1 × 10 ⁵ to 1 × 10 ⁷ mPa · s (25 ° C.).

(3) Packaging Step It is preferable to provide a step of subdividing the produced lightweight clay and packaging it. That is, usually, lightweight clay contains a relatively large amount of water and alcohol,
In order to maintain the water content in the lightweight clay and maintain the handleability, it is preferable to package the lightweight clay with a moisture-proof material, for example, a plastic material such as polyethylene or polypropylene. However, in order to reduce the expansion problem due to degassing of the unfoamed organic hollow microspheres, it is preferable to provide ventilation holes in the packaging material or to configure the packaging material from a gas-permeable material. In this case, in order to balance the maintenance of the water content in the lightweight clay and the reduction of the expansion problem, it is preferable to set the size of the vents to a value in the range of 0.01 to 100 μm, and 0.05 to 50 μm. Is more preferable, and the value is more preferably in the range of 0.1 to 20 μm.

[0047]

EXAMPLES [Example 1] (1) Preparation of lightweight clay After the following compounding materials were placed in a kneader having a capacity of 100 liters, a lightweight clay was prepared by rotating the kneader at a rotation speed of 40 rpm. White organic hollow microspheres 0.35 kg (average particle diameter 100 μm, L value 50 or more, weak alkali) Yellow pigment pigment (solid content) 0.19 kg (average particle diameter 0.086 um, standard deviation 0.026 um, 95% range 83-90 um) ) Carboxymethyl cellulose 0.20 kg (degree of etherification: 0.6) PVA 1.20 kg (degree of polymerization 1,800, saponification degree 95 mol%) Hardwood pulp 0.98 kg (average fiber length 1 mm) Water 11.05 kg phenolic preservative 0.03kg

(2) Evaluation of lightweight clay The obtained lightweight clay was evaluated for the following formability (film-forming property), light-weight property, color-forming property, stickiness and swelling property (storage property). . Obtained result (n = 5)
Are shown in Table 1.

Formability The formability (film formability) of the lightweight clay was evaluated according to the following criteria. In addition, if the evaluation of (circle) or more is obtained, it can be said that it has the moldability suitable for lightweight clay. A: A film having a thickness of 0.2 mm or less can be formed using a roll. ：: A film having a thickness of 1 mm or less can be formed using a roll. Δ: A film having a thickness of 5 mm or less can be formed using a roll. X: Even if a roll is used, a film having a thickness of 5 mm or less cannot be formed.

Lightweight The lightness of the lightweight clay was evaluated according to the following criteria. In addition, ○
If the above evaluation is obtained, it can be said that the lightweight clay has sufficient lightness. A: Density is 0.3 g / cm ³ or less. ：: The density is a value of 0.5 g / cm ³ or less. Δ: Density is a value of 0.7 g / cm ³ or less. X: The density is a value exceeding 0.7 g / cm ³ .

Colorability The colorability of the lightweight clay was evaluated according to the following criteria. In addition, ○
If the above evaluation is obtained, it can be said that the light clay has good color developability. ：: Clear color with a sense of transparency. ：: Vivid color. Δ: Slightly clear color. X: Unclear color.

Stickiness The tackiness of the lightweight clay was evaluated by touching the clay with the following criteria. In addition, if the evaluation of ○ or more is obtained, it can be said that the tackiness of the lightweight clay is good. A: Almost no stickiness. ：: There is some stickiness. Δ: Notable tackiness, but light weight clay does not transfer to fingers. X: There is remarkable stickiness, and lightweight clay is transferred to the finger.

Expandability 100 g of lightweight clay was formed into a rectangular shape, and the periphery thereof was wrapped with a polyethylene film having a thickness of 100 μm. After being left in an oven at 40 ° C. for one week in this state, the volume was measured, and the swellability (storage property) was evaluated based on the following criteria from the relationship with the initial volume. In addition, if the evaluation of (circle) or more is obtained, it can be said that it has the expandability (storage property) suitable for lightweight clay. A: Volume change rate is less than 3%. ：: Volume change rate is less than 10%. Δ: Volume change rate is less than 30%. X: Volume change rate is 30% or more.

[Examples 2 to 3, Comparative Examples 1 to 3] Light weight clay was prepared in the same manner as in Example 1 by changing the average particle diameter of the organic hollow microspheres and changing the addition amount in the composition shown in Table 1. Created. Next, the obtained lightweight clay was evaluated in the same manner as in Example 1. Table 1 shows the obtained results. As can be easily understood from the results, it was found that when the added amount of the organic hollow microspheres exceeded 3% by weight, the evaluation of the shaping property, the coloring property, and the swelling property of the lightweight clay was remarkably reduced.
On the other hand, it has been found that even when the amount of the organic hollow microspheres is less than 3% by weight, the weight of the lightweight clay can be sufficiently reduced.

[0055]

[Table 1]

[Examples 4 to 6, Comparative Examples 4 to 6] (1) Preparation of lightweight clay Example 1 was prepared by changing the addition amount of the fiber material in the composition shown in Table 1.
I made a lightweight clay as well. Next, the obtained lightweight clay was evaluated in the same manner as in Example 1. Table 2 shows the obtained results. In addition, Example 6 is a reproducibility test of Example 1, and Comparative Example 4 is a reproducibility test of Comparative Example 1.
As can be easily understood from the results, the amount of the added fiber material is 1
When it exceeds 0% by weight, it has been found that the formability and swellability of the lightweight clay are significantly reduced. On the other hand, it has been found that even when the amount of the fiber material added is less than 10% by weight, the weight of the lightweight clay can be sufficiently reduced.

[0057]

[Table 2]

[Examples 7 to 9, Comparative Examples 7 to 9] The amount of water added was changed so as to obtain the composition shown in Table 1, and in Examples 7 to 9, the amount of organic hollow microspheres was changed to 2.5. weight%,
In Comparative Examples 7 to 9, the addition amount of the organic hollow microspheres was 5% by weight.
, A lightweight clay was prepared in the same manner as in Example 1 except that inorganic hollow microspheres made of glass were added. Next, the obtained lightweight clay was evaluated in the same manner as in Example 1. Table 3 shows the obtained results. As can be easily understood from the results, when the amount of water added is less than 65% by weight,
It was found that the formability and color development of the lightweight clay were significantly reduced. It was also found that even when the amount of water exceeds 65% by weight, the tackiness of the lightweight clay can be sufficiently adjusted to an appropriate value. On the other hand, it has been found that by adding a predetermined amount of the inorganic hollow microspheres, the formability and color developability of the lightweight clay are further improved.

[0059]

[Table 3]

Example 10 Instead of the white organic hollow microspheres (average particle diameter 100 μm, L value of 50 or more, slightly alkaline) used in Example 1, brown organic hollow microspheres (average particle diameter 100 μm, L value) A lightweight clay was prepared and evaluated in the same manner as in Example 1 except that an acid (less than 50, acidic) was used.
Table 4 shows the obtained results together with the results of Example 1 and Comparative Example 1.

[0061]

[Table 4]

[0062]

According to the lightweight clay of the present invention, the average particle size of the organic hollow microspheres is set to a value within the range of 30 to 150 μm, and the amount of the organic hollow microspheres added is controlled with respect to the total amount. By setting the value within the range of 0.1 to less than 3% by weight, the moldability and the lightness are excellent, and the ambient temperature rises in the case of storing for a long time after covering with a packaging material, Even if the temperature is high, the problem of expansion is eliminated, excellent storage properties can be obtained, and a lightweight clay which is inexpensive to manufacture can be provided. Furthermore, according to the lightweight clay of the present invention, the addition amount of the organic hollow microspheres is small, so that even when a pigment for coloring is added, the dispersibility of the pigment is not hindered. , Excellent color developability can be obtained. According to the method for producing a lightweight clay of the present invention, the average particle size is 30 to 1
The organic hollow microspheres having a value within the range of 50 μm are used and kneaded with a kneader, and the amount of the organic hollow microspheres is within a range of 0.1 to less than 3% by weight based on the total amount. By making the value of, it is possible to provide a lightweight clay which is excellent in the formability and the lightness and also excellent in the storage property (expandability) at a low cost.

[0063]

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of organic hollow microspheres added to lightweight clay and the lightness and formability of the lightweight clay.

FIG. 2 is a diagram showing the relationship between the amount of organic hollow microspheres added to lightweight clay and the results of swelling evaluation.

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[Procedure amendment]

[Submission date] June 1, 2001 (2001.6.1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (8)

[Claims] In a lightweight clay containing organic hollow microspheres, the average particle diameter of the organic hollow microspheres is 30 to 150 μm.
m. A lightweight clay characterized by having a value within the range of m and an addition amount within a range of 0.1 to less than 3% by weight based on the total amount. 2. The lightweight clay according to claim 1, wherein the hollow organic microspheres are white. 3. The lightweight clay further contains a hydroxyl group-containing compound and a carboxyl group-containing compound, or any one of the polar compounds, and the amount of the polar compound added is 0.1 to 0.1% based on the total amount. The lightweight clay according to claim 1 or 2, wherein the value is within a range of 30% by weight. 4. The lightweight clay further contains fibers, and the added amount of the fibers is 1 to 1 with respect to the total amount.
The lightweight clay according to any one of claims 1 to 3, wherein the value is within a range of less than 10% by weight. 5. The lightweight clay further contains water, and the added amount of the water is 65 to 8 with respect to the total amount.
2. A value within a range of 5% by weight.
The lightweight clay according to any one of claims 4 to 4. 6. The lightweight clay further contains a pigment, and the amount of the pigment added is set to 0.1 to the total amount.
The lightweight clay according to any one of claims 1 to 5, wherein the value is within a range of 1 to less than 10% by weight. 7. The lightweight clay further contains inorganic hollow microspheres, and the added amount of the inorganic hollow microspheres is
The lightweight clay according to any one of claims 1 to 6, wherein the value is in the range of 0.01 to 10% by weight based on the total amount. 8. A method for producing a lightweight clay containing organic hollow microspheres, wherein the organic hollow microspheres having an average particle diameter within a range of 30 to 150 μm are used, and the organic kneaded mixture is kneaded using a kneader. A method for producing a lightweight clay, wherein the addition amount of hollow microspheres is a value within the range of 0.1 to less than 3% by weight based on the total amount.