JP2951933B2 - Molding materials for products using paper fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable product utilizing paper fiber such as waste paper or paper pulp, for example, a seedling growing container, or a product requiring anti-static properties, for example, a CD packaging container for mailing. The present invention relates to the technology of molding materials for molding such as.

[0002]

2. Description of the Related Art As a conventional molding material for molding a product using waste paper, a material obtained by mixing starch and water with kneaded waste paper and kneading the mixture has been proposed by the applicant. And
When molding using the molding material, a step of kneading the molding material to facilitate supply and filling into the cavity of the molding die, and water added to the molding material filled in the cavity by a degassing means. A step of vaporizing and drying and solidifying is required (for example, see JP-A-9-76213 and JP-A-9-109113).

[0003]

When a product using waste paper is molded from a conventional molding material, in the step of kneading the molding material, the molding material is liable to stick to a vessel wall, a die, or the like. There was a problem that the property became worse.

In the step of drying and solidifying the molding material filled in the cavity of the molding die, the filled molding material starts drying from the surface in contact with the mold wall surface forming the cavity to form a skin layer. Moreover, the skin layer is extremely thin immediately after the filling is completed, and there is a fear that the skin layer will adhere to the mold wall surface when a steam pressure or a filling pressure is applied to the skin layer. When the skin layer adheres to the mold wall surface, when the water added to the molding material is turned into steam by the mold heated to a high temperature,
There is a problem that the water vapor hardly deaerates from the deaeration means via the interface between the mold wall surface and the skin layer.

[0005] Furthermore, when the skin layer is in close contact with the mold wall surface, when the solidified molded body is released from the mold, the molded body tends to crack due to frictional resistance with the mold wall surface. .

According to the present invention, when the molding material is kneaded, it does not easily adhere to the vessel wall, etc., when the molding material is used, the added water is easily deaerated, and when the mold is released, the release is easy. The purpose is to prevent the occurrence of cracks.

[0007]

In order to solve the above-mentioned problems, the present invention relates to a molding material for a product utilizing paper fibers, wherein at least paper and fibers to which starch and water have been added are made of a non-alkali metal. Long-chain fatty acid salts are added and mixed.

When kneading, the workability can be improved without sticking to a vessel wall or the like.
In molding, water can be easily degassed to shorten the drying time, and the mold can be released without cracking.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A molding material for a product utilizing the paper fiber of the present invention is obtained by adding at least starch, water and a non-alkali metal long-chain fatty acid salt to the paper fiber and kneading the mixture. .

[0010] Since the paper fibers are generally finely divided, they are easily dispersed even when compounded as a molding material, and the surface of the molded article can be made excellent in smoothness. Further, since starch has a molecular structure very similar to paper fibers, the paper fibers can be firmly adhered and bonded to form a molded body in which the paper fibers are firmly integrally bonded. Furthermore, since starch effectively acts as a binder, even when the thickness of the molded body is thin, the molded body has high strength and high rigidity and is less likely to be warped, and the starch removes water. Since it becomes infusible later, the molded body can be easily released from the mold in the high temperature state.

Further, the non-alkali metal long-chain fatty acid salt is
Having a non-polar part based on a fatty acid chain part and a polar part based on a non-alkali metal part, so that it has a surfactant function,
In addition, it is insoluble in water and has water repellency, and further, has lubricity regardless of whether it is in a molten or powder state. Therefore, by adding such a metal salt of a long-chain fatty acid, the metal salt of the long-chain fatty acid acts as an internal mold release agent, and in the step of plasticizing and kneading the molding material, the molding material becomes The workability can be improved by preventing adhesion to a die or the like. In addition, even if a skin layer is formed on the surface of the molding material by drying in the cavity, the presence of the metal salt of the long-chain fatty acid makes it difficult to adhere to the cavity wall surface. When the heated water is turned into steam by the heated mold, the steam passes through the interface between the skin layer of the molding material and the cavity wall surface, and then is easily removed from the degassing means or the parting surface of the mold. Can be degassed. Further, since the metal salt of the long-chain fatty acid is present on the surface of the molded body and reduces the frictional resistance with the mold wall surface,
The molded article can be released from the mold without cracking.

A mixture of paper fiber, starch and a metal salt of a long-chain fatty acid is solid or clay at room temperature by adding water and kneading the mixture. In the case of molding by a method, when filled in a high-temperature mold, it becomes an extremely low-viscosity fluid state, and becomes a molding material that can be smoothly filled even in a thin portion in a cavity in a molding step. When the molding material is filled in the cavity, the surface is first dried from the surface to form a skin layer, and the skin layer is solidified in a state where the water vapor pressure is applied from the inside and is constantly pressed against the mold wall surface. Therefore, the appearance dimensions of the molded article match those of the cavity, and a molded article free from molding shrinkage and warpage can be obtained.

Further, the water added into the molding material is
In the hot cavity, it is rapidly released as water vapor. Since bubbles are formed in the trace of the evaporation of water, the proportion of water to be added directly affects the density of the molded body. In order to increase the size and obtain a high-density and high-strength molded body, it can be achieved by reducing the proportion of water added.

The paper fibers include used newspapers, magazines, papers such as corrugated cardboard, paperboard, cut waste paper, broken paper generated in the paper making process, waste paper, cut-off paper, used waste paper, and the like. Although it can be used in such a paper state, it can also be used in a pulp state.

[0015] Further, since the main components paper fiber, starch and polyvinyl alcohol are biodegradable, the obtained molded article also has biodegradability. In addition, the metal salt of a long-chain fatty acid reduces the adhesiveness to a device wall or the like in the process of plasticizing and kneading the molding material, improves workability, and easily releases and degass water vapor in the molding process. The molding cycle can be shortened. In the step of releasing the molded product, the metal salt of a long-chain fatty acid imparts lubricity to the surface of the molded product, thereby facilitating release and preventing the molded product from cracking. Has the effect that can be. Further, water enables uniform kneading of the molding material, makes the molding material flowable in a high-temperature mold, and facilitates filling in the cavity.

Further, from the viewpoints of the strength of the molded product, the shape retention of the molded product, the fluidity of the molding material, the kneading property of the molding material, the deaeration of water vapor, etc. 100 parts of a mixture of 100 to 90 parts of starch and 10 to 50 parts of starch, and 50 parts to 200 parts of water, and 100 parts of a mixture of 0.2 to 2.
0 parts are added. The preferred mixing ratio of paper fiber, starch and water is 60-80 parts of paper fiber and 20-starch.
60 to 150 parts of water is added to 100 parts of the mixture with 40 parts of the mixture, and the preferable mixture ratio of the metal salt of the long-chain fatty acid is 100 parts of the mixture to which water is added, and Is added in an amount of 0.5 to 1.5 parts.

The main component of the molding material is paper fiber 50.
A mixture of about 90 parts and 10 to 50 parts of starch is used, but when the paper fiber is 50 parts or less and the starch is 50 parts or more,
Although molding is possible, the strength of the molded article is unpreferably reduced because the strength of the molded article is remarkably reduced. Also, when the paper fiber is 90 parts or more and the starch is 10 parts or less, the surface state of the molded article becomes rough, and Is undesirably reduced. In addition, 50 to 200 parts of water is added to and kneaded with 100 parts of the above-mentioned composition, and when the added water is 50 parts or less, the kneaded molding material is formed into a pellet or tablet. It is difficult to maintain the shape, and the fluidity in the heated mold rapidly decreases, which is not preferable. On the other hand, when 200 parts or more of water is added and kneaded, the resulting kneaded material becomes a remarkably low-viscosity mud, and is molded into a deaeration means when molded by a normal molding method such as injection molding or compression molding. The material easily penetrates to make continuous molding difficult, and it takes time to dry and solidify the molding material, which is not preferable.

Further, a blend of paper fiber, starch and water 10
0 to 0 parts, 0.2 to 2.
0 parts, preferably 0.5 to 1.5 parts are added, but when 0.2 parts or less of the non-alkali metal long-chain fatty acid salt is added, the lubricant effect is rapidly weakened, and the molding material In the kneading step, the sticking prevention function is reduced, so that the sticking to the device walls and the like becomes easy, and in the forming step, the time for degassing the steam becomes longer. If the size is small, it is difficult to release the mold smoothly, and there is a fear that cracks may occur in the molded body, which is not preferable. On the other hand, when the non-alkali metal long-chain fatty acid salt is added in an amount of 2.0 parts or more, the lubricating effect is too strong and the frictional resistance with the apparatus wall is reduced in the kneading process of the molding material, so that the uniformity can be obtained in a short time. It becomes difficult to knead, and further, if the molding materials merge inside the cavity, the strength of the joint decreases, which is not preferable.

The non-alkali metal long-chain fatty acid salts include calcium stearate, magnesium stearate, zinc stearate, aluminum stearate,
Strontium stearate, calcium laurate,
Magnesium laurate, zinc laurate, aluminum laurate, and strontium laurate alone or in combination of two or more are easily mixed homogeneously with paper fiber and starch, and have excellent lubricity in both molten and powdered states. This is effective because the workability can be improved by the lubricating action and the releasing action by the interfacial lubrication effect.

Furthermore, when a starch obtained by compounding polyvinyl alcohol by replacing 10 to 50%, preferably 20 to 40% of starch with polyvinyl alcohol is used, the resulting molded article exhibits excellent toughness and cracks. There is no effective.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to an example of a molding material for molding a seedling growing container as shown in FIG. FIG. 1 is a side view of the seedling raising container in which a main part is cut away, 1 is a container main body, and 2 is a drain hole.

In the composition of the material for forming the container body 1, sliced powder generated during assembling a milk pack, so-called paper powder, is used as the paper fiber, and corn flour (Oji Cornstarch Co., Ltd.) is used as the starch. Cone Y)
NM-14 manufactured by Nippon Synthetic Chemical Industry Co., Ltd. is used as a polyvinyl alcohol (hereinafter referred to as PVA) which partially substitutes the starch. Examples of the non-alkali metal long-chain fatty acid salt (hereinafter abbreviated as metal soap) include zinc stearate (hereinafter abbreviated as St-Zn), barium stearate (hereinafter abbreviated as St-Ba), Zinc laurate (hereinafter abbreviated as La-Zn) is used. These materials are blended at the ratios shown in Table 1. In addition, as metal soap,
A product manufactured by Kishida Chemical Co., Ltd. adjusted for test research is used.

The mixing ratio of paper powder and starch, which are solid materials, is 7: 3, the mixing ratio of solid material and water is 10: 7 or 10:10, and water is added to the solid material. The mixing ratio between the main material and the metal soap is as follows.
Metal soap is 0.5 to 1.5 parts with respect to 00 parts.

[0024]

[Table 1]

Next, adjustment of the molding material will be described. Paper powder, starch, metal soap, and water are sequentially weighed in a polybeaker having an inner volume of about 1 liter to a total amount of 55 to 60 g, and then stirred, plasticized and kneaded to obtain a molding material. As the kneading conditions, a Labo Plastomill 15-50 manufactured by Toyo Seiki Seisaku-sho, Ltd. was used, and kneading was performed at a set temperature of 70 ° C. and a kneading speed of 100 rpm for 5 minutes. did. The temperature for plasticizing and kneading the molding material is effectively from 60 to 100 ° C., preferably from 65 to 80 ° C. If the kneading temperature is 60 ° C. or less, gelatinization of the starch becomes insufficient and the homogenization occurs. Molding material is difficult to obtain, and 100
If the temperature is higher than 0 ° C., drying of the material starts during kneading, which is not preferable.

Further, since this molding material is biodegradable and contains a large amount of water, mold generation is observed in 7 to 10 days under ordinary storage conditions of sealing at 15 ° C. Therefore, when stored for a long period of 10 days or more, as an antibacterial agent, for example, Amorden SK-95 manufactured by Daiwa Chemical Industry Co., Ltd.
0 is preferably added at the time of about 0.3% kneading. However, in this example, an antibacterial agent was not added because the storage period was short.

The effect of the compounded molding material on the kneading performance will be described with reference to Table 2.

[0028]

[Table 2]

When PVA is combined with starch, it can be seen that the torque value at the time of kneading only slightly increases, and the adhesion due to adhesion to the vessel wall of the kneading device hardly changes (Comparative Example 2). , 4, and Examples 2 to 4, 6, 8, and 10). In the case of the example in which the metal soap was added, it was found that the adhesiveness to the vessel wall of the kneading apparatus was improved as compared with the comparative example, and that the larger the blending amount was, the more effective it was to prevent the adhesiveness. (See Examples 1 to 4). When the mixing amount of water is increased, the torque value during kneading is significantly reduced and becomes soft, so when removing the kneaded material, it cannot be easily peeled off with only a fingertip, and when dried on the wall Can not be peeled off with a wire brush (see Comparative Examples 3 and 4), but by adding metal soap, it can be easily peeled off with a wire brush even when it is dried on the container wall, and it can be cleaned. (See Examples 9 and 10). In addition, in the case of Comparative Examples 1-4,
It is difficult to remove the substance adhered to the container wall and dried by peeling with a wire brush, and it was necessary to immerse in hot water to soften and then peel with a wire brush. Further, regarding the type of metal soap, St-Zn
In contrast, in the case of St-Ba and La-Zn, there is a slight difference in the torque value during kneading, but it can be seen that there is no difference in the releasability due to the adhesion to the vessel wall. (See Examples 1, 2, 5 to 8).

Next, a case where a seedling raising container is molded using the molding tablet formed as described above will be described.

As a molding device, a double-acting 50-ton compression press manufactured by Marunachi Iron Works Co., Ltd. was used. As a mold, steam generated during molding was released to the outside of the mold to remove air. An air vent and a degassing means are used. Further, when the molding tablet is filled in the cavity, if the pressure in the cavity becomes 30 kgf / mm ² or more,
Since there is a possibility that the molding material may flow into the degassing vent, the parting surface of the mold, which is the final filling position of the molding material,
An outlet for discharging excess material is provided, and the mold temperature is 160
２００200 ° C. The tablet for molding is solid at room temperature, but softens instantaneously in the mold by heat and pressure to have a low viscosity, and a maximum of 210 kgf /
Molding could be performed at a pressure of 5 kgf / mm ² or less with respect to a gauge pressure of ² mm ² .

The water vapor generated in the cavity is released to the outside of the mold mainly through the degassing vent. When the release of the water vapor is completed, the drying of the molded article is completed. The molded article can be released.

The effects of the above-described molding on the formability will be described with reference to Tables 3 and 4 in terms of the drying time and the occurrence of cracks. The drying time was measured from the time when the mold clamping was started until the time when the release of water vapor was completed. The cracking rate indicates the rate at which cracks occurred in 30 molded articles. ing.

[0034]

[Table 3]

[0035]

[Table 4]

Table 3 shows the case where the mold temperature was set to 180 ° C., but in the case of the example in which the metal soap was added, the drying time was shorter and the occurrence of cracks was smaller than in the comparative example. I understand. When the drying time is shortened, the molding cycle can be shortened, which is extremely advantageous in the molding step. The addition of the metal soap can shorten the drying time because the presence of the metal soap makes it difficult for the molding material to adhere to the cavity wall surface, and the generated steam passes through the interface between the wall surface and the molding material. This is due to the fact that it is easy to release the material outside the mold. If the amount of water added is large and the moisture content of the molding material is high, the material becomes soft and the release of water vapor becomes difficult, the density of the molded product after drying decreases, the strength decreases, and cracks easily occur. However, it was found that by adding the metal soap, the drying time could be shortened and the cracks were reduced (see Examples 9 and 10).

When the temperature of the mold is high, the drying time can be shortened, but the steam is also generated rapidly. Therefore, even in the step of filling the molding material, the steam is partially generated and foamed. And easily cause cracking. However, it can be seen that by adding the metal soap, the drying time can be shortened and the occurrence of cracks can be reduced (see Table 4). However, in the case of a material having a high moisture content, if the mold temperature is 200 ° C., cracks cannot be avoided even if metal soap is added. Therefore, in order to realize stable production, the mold temperature should be lower than 200 ° C. Is preferred.

[0038]

The present invention is embodied in the form described above and has the following effects.

In the kneading step before the molding material is supplied to the cavity, it becomes difficult to adhere to a vessel wall or the like. In the molding step in which the kneaded material is filled into the cavity and molded, even the corners of the cavity are formed. It exhibits low viscosity fluidity that facilitates smooth filling, and the added water is extremely degassed and easily dried. Further, a product molded using this molding material has excellent surface smoothness, does not warp even in the case of high rigidity and is thin, and has little shrinkage and cracks.

Further, the obtained product has heat resistance that can be used at a high temperature of 200 ° C. or less, has no chargeability, and is easily biodegraded by bacteria in soil and easily broken down.

This molding material can reuse waste paper and the like and is easily broken down by biodegradation. Therefore, it can be used for an environmentally friendly seedling raising container, or even if its thickness is thin. Since there is no warpage and no electrification, it can be used as a packaging container for mailing CDs.

[Brief description of the drawings]

FIG. 1 is a side view of a seedling raising container molded using a molding material according to an embodiment of the present invention, in which main parts are cut away.

[Explanation of symbols]

 1 container body 2 drain hole

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiko Funaki 1-3-7 Oinmachi, Moriguchi-shi, Osaka Examiner, Keiko Nagai, Daiho Kogyo Co., Ltd. (56) References JP-A-9-76213 (JP) , A) JP-A-64-45894 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B27N 3/00-5/00 D21H 1/00-1/22

Claims (6)

(57) [Claims] A non-alkali metal long-chain fatty acid salt is added to 100 parts of a mixture obtained by adding 50 to 200 parts of water to 100 parts of a mixture of 50 to 90 parts of paper fiber and 10 to 50 parts of starch. A molding material for a product using paper fibers kneaded by adding 2.0 parts. 2. 100 parts of a mixture of 50 to 90 parts of paper fiber and 10 to 50 parts of starch and 50 to 200 parts of water are added to 100 parts of a mixture of 0.5 to 0.5 parts of a non-alkali metal long-chain fatty acid salt. A molding material for a product using paper fiber kneaded by adding 1.5 parts. 3. A non-alkali metal long-chain fatty acid salt is added in an amount of 0.2 parts to 100 parts of a mixture obtained by adding 60 to 150 parts of water to 100 parts of a blend of 60 to 80 parts of paper fiber and 20 to 40 parts of starch. A molding material for a product using paper fibers kneaded by adding 2.0 parts. 4. A mixture of 60 to 80 parts of paper fiber and 20 to 40 parts of starch and 100 parts of a mixture of 60 to 150 parts of water is added with 0.5 part of a non-alkali metal long-chain fatty acid salt. A molding material for a product using paper fiber kneaded by adding 1.5 parts. 5. A molding material for a product using paper fibers according to claim 1 , wherein 10 to 50% of the starch is substituted by polyvinyl alcohol. 6. The molding material for a product using paper fibers according to claim 1 , wherein 20-40% of the starch is substituted with polyvinyl alcohol.