JP2017115065A - Molding material and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding material for manufacturing an injection molded body or a compression molded body which is dispersed quickly in water.SOLUTION: There is provided a molding material consisting of a natural fiber, a water-soluble binding material, water and a long chain aliphatic acid salt of non-alkali metal, used for molding an injection molded article or the compression molded article and having water dispersibility with dispersion starting in 10 min. and separation to a fragment having area of about 50 mm2 or less in 15 min. when a molded flat sheet with length of 10 mm, width of 10 mm and thickness of 1 mm is put into water of 300 ml and stirred at 650 rpm.SELECTED DRAWING: None

Description

  The present invention relates to a molding material capable of producing an injection molded product or a compression molded product that is rapidly dispersed in water, and a molded product using the same.

  Conventionally, a fibrous main raw material kneaded by adding a water-soluble binder and water is filled in a heated mold, and the added water is vaporized and removed to dry and solidify the injection molded product and the compression molded product, and these Molding materials used for production are known.

  For example, Patent Document 1 discloses a molding material in which starch, water and a non-alkali metal long-chain fatty acid salt are added to a paper fiber and kneaded. Patent Document 2 and Patent Document 3 contain vegetable fiber, binder, water, and metal soap, and in order to reduce the amount of water contained in the material, glycerin that gives fluidity to the material instead of water. A molding material containing such a fluidity imparting material and an injection molded product using the same are disclosed. Further, Patent Document 4 supplies a raw material kneaded by adding water to a biodegradable plant-based fiber such as waste paper and a biodegradable water-soluble binder such as starch, to a heated mold, A seedling container having biodegradability obtained by evaporating and removing water in a raw material to dry and solidify is disclosed. In addition, Patent Document 5 discloses a tray for storing a food that is formed by molding a molding material made of a mixture of paper fibers, a starch-based binder, and water, and vaporizes and removes moisture to dry and solidify.

  By the way, since the water-soluble polymer is used for the injection molded product or the compression molded product molded by using the molding material in Patent Documents 1 to 5 above as a binder or binder, Although it swells and deforms, it does not swell, disperse or disintegrate in a short time after being poured into water, and an injection molded product or a compression molded product that is rapidly dispersed in water has not been obtained.

  For example, in Examples 1 to 4 of Patent Document 4, the immersion test result of a compression molded product obtained by molding and drying a molding material in which starch and water are added to a paper material is disclosed. It does not collapse even afterwards, and it is shown that it retains its form although there is a difference in hardness. Patent Document 5 describes that an injection molded product obtained by molding and drying a molding material obtained by adding starch-based binder and water to paper fiber can absorb moisture leached from food, It has been suggested that the molded article maintains its form as a moisture absorbing container without swelling, deformation or dispersion with water.

Japanese Patent No. 2995133 JP 2002-309095 A JP-A-2005-15814 Japanese Patent Laid-Open No. 10-309135 JP 2008-94463 A

  The molded product, which is formed by adding a water-soluble binder and water to a fibrous main raw material and kneading it in a heated mold and then dried and solidified, can be discarded as burning waste, and a biodegradable substance is used as the raw material. What was used is expected to be used as a material for reducing the environmental load that biodegrades in the soil.

  However, since the conventional molded product does not swell, disperse or disintegrate in water in a short time, there is a problem that it cannot be used as a disposable article that is dispersed and disintegrated in water after use like a toilet article.

  The present invention solves the above-described problems, and an object thereof is to provide a molding material for producing an injection molded product or a compression molded product that is rapidly dispersed in water and a molded product using the same.

  The gist of the present invention will be described.

A molding material made of natural fiber, water-soluble binder, water and a long-chain fatty acid salt of non-alkali metal, and used for molding an injection molded product or a compression molded product. A molded flat plate having a length of 10 mm, a width of 10 mm and a thickness of 1 mm A molding material characterized by having a water dispersibility that disperses into fragments having an area of about 50 mm ² or less within 15 minutes when the mixture is poured into 300 ml of water and stirred at 650 rpm. It is concerned.

  It is a molding material used for molding injection molded products or compression molded products, consisting of natural fibers, water-soluble binders, water and non-alkali metal long-chain fatty acid salts, and uses carboxymethylcellulose salt as a water-soluble binder. The present invention relates to a molding material characterized by the above.

  The molding material according to any one of claims 1 and 2, wherein the water-soluble binder is carboxymethylcellulose salt, and a ratio of the natural fiber to the water-soluble binder is natural fiber: water-soluble binder. = 75 to 30% by mass: 50 to 100 parts of water and 0.3 to 2.0 parts of a non-alkali metal long-chain fatty acid salt are blended in 100 parts of a mixture of 25 to 70% by mass. This relates to the molding material to be used.

  The molding material according to any one of claims 1 to 3, wherein the water-soluble binder is a carboxymethyl cellulose salt, and the carboxymethyl cellulose salt is an alkali metal salt having a degree of etherification of 0.5 to 1.0. The present invention relates to a molding material.

  Moreover, the molding material of any one of Claims 1-4 WHEREIN: 25-50 mass% of the carboxymethylcellulose salt used as the said water-soluble binder is replaced with cold water soluble polyvinyl alcohol, It is characterized by the above-mentioned. It relates to molding materials.

  Further, the present invention relates to a molded article obtained by injection molding or compression molding the molding material according to any one of claims 1 to 5.

  Since this invention was comprised as mentioned above, it becomes a molding material for manufacturing the injection molded product or compression molded product which disperse | distributes rapidly in water, and a molded product using the same.

It is a table | surface which shows an experimental result. It is a table | surface which shows an experimental result. It is a table | surface which shows an experimental result.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  An injection molded product or a compression molded product molded using a molding material comprising the natural fiber of the present invention is rapidly dispersed in water.

  Therefore, the molded product formed according to the present invention is a disposable product such as a packaging buffer that can be reduced in water after use, a container for dried food, and a toilet that can be dispersed and washed away using a dedicated water dispersion treatment facility after use. It can be used for cleaning tools, urinalysis containers, toilet articles such as disposable pots, and festival items such as sink lanterns and sinks.

  Specific embodiments of the present invention will be described with reference to the drawings.

  The present embodiment is a molding material made of natural fiber, a water-soluble binder, water, and a long-chain fatty acid salt of a non-alkali metal and used for molding an injection molded product or a compression molded product.

Specifically, when the molding material for producing the water-dispersible injection molded product or compression molded product of this example is molded into a flat plate having a length of 10 mm, a width of 10 mm, and a thickness of 1 mm by an injection or compression molding method, Dispersion begins within 10 minutes by being poured into 300 ml of water and stirred at 650 rpm, and has a rapid water dispersibility that breaks up into pieces having an area of about 50 mm ² or less within 15 minutes.

  Since the degree of water dispersibility required for a molded product varies depending on the purpose of use, a molded product having water dispersibility suitable for the application can be produced by adjusting the composition of the molding material and the shape of the molded product. .

  A molding material for producing an injection molded product or a compression molded product having water dispersibility includes a natural fiber, a water-soluble binder, water, and a long-chain fatty acid salt of a non-alkali metal.

  Natural fibers include wood pulp such as paper pulp, dissolving pulp, mercerized pulp, fluff pulp, non-wood pulp obtained from cotton, linter, flax, manila hemp, sisal hemp, bagasse, kenaf, straw, etc. And pulverized plant pulp such as used paper pulp, rice husk, and wood flour. In addition, lyocell fiber obtained by purifying natural cellulose and rayon fiber obtained by regenerating natural cellulose can be used in the category of natural fiber.

  The water-soluble binder is soluble in water when kneaded with natural fibers and water, and can be easily dissolved in water even after the kneaded product is molded, dried and solidified in a mold. Preferred are carboxyalkyl cellulose salts such as carboxymethyl cellulose salt and carboxyethyl cellulose salt, cold water soluble polyvinyl alcohol, carboxymethylated starch, methyl cellulose, hydroxyethyl cellulose, polyacrylate, butenediol / vinyl alcohol copolymer, and the like.

  These water-soluble binders are kneaded with natural fibers and water to form a molding material, but the fluidity and the like when filling in the mold and the water dispersibility and biodegradability of the molded product are appropriate. Select and use alone or in combination of two or more.

  Among the water-soluble binders, carboxymethylcellulose salt is excellent in water dispersibility of molded products, binding power with natural fibers, and fluidity when filling a mold, and selects a specific degree of etherification and salt type. As a result, the best water dispersible molding can be obtained.

  The degree of etherification of the carboxymethyl cellulose salt is 0.5 to 1.0, preferably 0.60 to 1.00, more preferably 0.65 to 0.75. If the degree of etherification is less than 0.5, the flowability when filling the molding material into the mold is low and the molded product becomes brittle. Since it takes time to dry and solidify the molding material filled in the mold, productivity of the molded product is lowered.

  Carboxymethylcellulose salts are known to be water-soluble alkali metal salts, calcium salts, magnesium salts, ammonium salts, etc., but alkali metal salts such as sodium salts are preferred in that the water dispersibility of the molded product is good. Preferably, calcium salt, magnesium salt, and ammonium salt are inferior in water dispersibility of the molded product. Therefore, in this example, carboxymethylcellulose sodium salt is employed.

  In this example, carboxymethyl cellulose salt is used as a water-soluble binder, and the ratio of natural fiber to water-soluble binder is natural fiber: water-soluble binder = 75-30% by mass: 25-70% by mass. A mixture obtained by adding 0.3 to 2.0 parts by mass of a non-alkali metal long-chain fatty acid salt to a mixture obtained by adding 50 to 100 parts by mass of water to the part is preferable.

  The ratio of the number of blends of natural fiber and carboxymethylcellulose salt in the molding material affects the moldability when filling the mold, the water dispersibility and physical properties of the molded product, and the ratio of appropriate natural fiber: carboxymethylcellulose salt is 75 mass. %: 25% by mass to 30% by mass: 70% by mass, and preferably the ratio of natural fiber: carboxymethylcellulose salt is 70% by mass: 30% by mass to 40% by mass: 60% by mass. If the natural fiber exceeds 75% by mass and the carboxymethyl cellulose salt is less than 25% by mass, the flowability when filling the molding material into the mold, the shape retention of the molded product, the surface property, the strength, etc. are not preferable. . On the other hand, when the natural fiber does not reach 30% by mass and the carboxymethyl cellulose salt exceeds 70% by mass, the surface smoothness and strength of the molded product decrease, and the amount of carboxymethyl cellulose salt more expensive than the natural fiber increases, resulting in cost reduction. It is unfavorable to increase.

  Of the carboxymethylcellulose salt used as the water-soluble binder, 25 to 50% by mass can be replaced with cold water-soluble polyvinyl alcohol. Replacing a part of the carboxymethylcellulose salt with cold water-soluble polyvinyl alcohol improves the water dispersibility and strength of the molded product. When the replacement amount of the cold water-soluble polyvinyl alcohol is less than 25% by mass or exceeds 50% by mass, the water dispersibility of the molded product is lowered, which is not preferable.

  In this example, 50 to 100 parts by mass of water is added to 100 parts by mass of a mixture of natural fiber and carboxymethyl cellulose salt which is a water-soluble binder. When the amount of water added is less than 50 parts by mass, the load during kneading increases, making uniform kneading impossible, and it becomes difficult to maintain the shape of the kneaded molding material in the form of pellets or tablets. . On the other hand, when the amount of water added exceeds 100 parts by mass, it becomes an extremely low viscosity and mud-like kneaded product, which makes it difficult to form and dry.

  The non-alkali metal long-chain fatty acid salt of this example consists of a non-polar part based on a fatty acid chain part and a polar part based on a non-alkali metal part, is insoluble in water, has water repellency and a surface active function, and melts. Even if it is in any state of powder and powder, it has lubricity.

  For this reason, the non-alkali metal long-chain fatty acid salt acts as an internal lubricant when the molding material is kneaded, and can prevent the molding material from sticking to the vessel wall and improve workability. In addition, it acts as an external lubricant in the mold, and inhibits adhesion to the mold wall surface when a skin layer is formed on the surface of the molding material by drying, and a flow path through which water is vaporized and removed from the molding material. It has the effect of facilitating the formation, reducing the frictional resistance between the molded product and the mold wall surface, and releasing the molded product without generating cracks.

  Non-alkali metal long chain fatty acid salts include, for example, calcium stearate, magnesium stearate, zinc stearate, calcium laurate, magnesium laurate, zinc laurate, aluminum laurate, strontium laurate, aluminum stearate, strontium stearate, etc. However, it is not particularly limited to these. These may be used alone or in combination.

  The non-alkali metal long-chain fatty acid salt is preferably added with 0.3 to 2.0 parts by mass with respect to 100 parts by mass in total of the natural fiber and the water-soluble binder. When the added amount of the non-alkali metal long chain fatty acid salt is less than 0.3 parts by mass, the lubricant effect is lowered, and the adhesion preventing function is lowered in the kneading process of the molding material, so that it easily adheres to the wall surface of the molding apparatus. Moreover, in the molding process, the time for degassing water vapor becomes longer. Further, when releasing the molded product, if the draft is small, it is difficult to release smoothly, and cracks may occur in the molded product, which is not preferable.

  On the other hand, if the addition amount of the non-alkali metal long chain fatty acid salt exceeds 2.0 parts by mass, the lubricant effect is too strong in the kneading process of the molding material and the frictional resistance with the wall surface of the kneading machine is reduced. It becomes difficult to knead uniformly. Furthermore, if the molding material joins inside the mold during molding, the strength of the joint is lowered, which is not preferable.

  In the molding material thus obtained, an antibacterial agent for preventing wrinkles and a polyhydric alcohol such as glycerin for imparting flexibility can be added as necessary.

  The moisture content of the molding material is 30% by mass to 65% by mass, preferably 35% by mass to 50% by mass, and more preferably 40% by mass to 45% by mass. If the water content is less than 30% by mass, the fluidity of the molding material is remarkably lowered and molding becomes difficult. On the other hand, if the water content exceeds 65% by mass, it takes a long time for degassing and releasing water vapor, and the time required for molding cannot be shortened.

  Since the present embodiment is configured as described above, it is possible to obtain a molded article and a molding material that have sufficient mechanical strength and good appearance and can be rapidly dispersed in water.

  An experimental example supporting the effect of the present embodiment will be described below. Moreover, the evaluation method used in the experimental example is shown below. This was commonly used in each experimental example.

-Preparation of test piece A molding material was put into an injection molding machine (NEX5000 manufactured by Nissei Plastic Industries), and a JIS No. 1 type test piece having a thickness of 1 mm as defined in JIS K7113 was prepared.

-Water dispersion time A 10 mm square test piece was cut out from the JIS No. 1 test piece. A 300 ml beaker was charged with 300 ml of deionized water, and one test piece was added while stirring at 650 rpm with a stirrer. The dispersion state of the test pieces was observed when 10 minutes and 15 minutes had passed after the addition. A sample whose area around the test piece was dispersed in water and the area was reduced by about 20% was subdivided into ^two or more pieces having an area of about 1 mm ² or more and about 50 mm ² or less. B is a specimen, C is a specimen dispersed in small particles of about 1 mm square, there is a small amount of undispersed material, but most of the specimen is D, the specimen is completely monofilament Dispersed samples are classified as E, those in which the shape of the test piece does not change is classified as Z, and those after 10 minutes are classified as A, B, C, D, E and evaluated as having rapid water dispersibility. It was written as “○”, and those of Z were evaluated as “no water dispersibility” and written as “x”.

-Injection moldability The test piece was prepared and visually observed for defects in the shape of the test piece, peelability from the mold, and the like, and the moldability of the molding material into the mold was investigated. A test piece with no defect and good peeling from the mold is evaluated as good injection moldability and marked with a circle, and there is a part that is not filled with molding material in the mold, and the specimen has a defect Those having a part that could not be peeled off from the mold were evaluated as poor injection moldability and indicated by x.

-Surface property of molded article The surface property was investigated by visually observing the surface of the test piece. A molded article having a smooth surface was evaluated as having good surface properties and marked with a circle. The surface of the molded product with large irregularities and poor smoothness was evaluated as x with an evaluation of poor surface properties.

-Strength of molded product The tensile strength of the test piece was measured in accordance with JIS K7113, and the strength of 50% or less of the tensile strength of the molded product having no water dispersibility shown in Comparative Example 1 was considered insufficient. It evaluated and described with x.

[Experimental Example 1]
60% by weight of softwood bleached kraft pulp and 40% by weight of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 are blended as a water-soluble binder, and 100 parts by weight of 70 parts by weight of water and 1.6 parts by weight of zinc stearate. A molding material having a water content of 40% by mass added and kneaded was prepared. A test piece was prepared from this molding material, and the water dispersibility, injection moldability, surface property and strength of the molded product were evaluated and shown in FIG.

  In addition, in FIGS. 1-3, CMC shows carboxymethylcellulose sodium salt, PVA shows cold water soluble polyvinyl alcohol, and starch shows corn starch.

[Experiment 2]
A test piece was prepared and evaluated in the same manner as in Experimental Example 1 except that the water-soluble binder was changed to carboxymethylcellulose sodium salt having a degree of etherification of 0.9, and is shown in FIG.

[Experiment 3]
A test piece was prepared and evaluated in the same manner as in Experimental Example 1 except that the water-soluble binder was carboxymethylcellulose sodium salt having a degree of etherification of 0.6, and is shown in FIG.

[Experimental Example 4]
Except for blending 70% by weight of softwood bleached kraft pulp and 30% by weight of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder, a test piece was prepared and evaluated in the same manner as in Experimental Example 1, This is described in FIG.

[Experimental Example 5]
Except that 50% by mass of bleached softwood bleached kraft pulp and 50% by mass of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder were prepared and evaluated in the same manner as in Experimental Example 1, This is described in FIG.

[Experimental Example 6]
Except that 40% by mass of bleached softwood bleached kraft pulp and 60% by mass of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder were prepared and evaluated in the same manner as in Experimental Example 1, It described in FIG.

[Experimental Example 7]
Except for blending 30% by weight of softwood bleached kraft pulp and 70% by weight of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder, a test piece was prepared and evaluated in the same manner as in Experimental Example 1, It described in FIG.

[Experimental Example 8]
Tested in the same manner as in Experimental Example 1 except that a mixture of 30% by mass of sodium carboxymethylcellulose having a degree of etherification of 0.7 and 10% by mass of cold water-soluble polyvinyl alcohol having a saponification degree of 71% was used as the water-soluble binder. A piece was prepared and evaluated and is shown in FIG.

[Experimental Example 9]
Tested in the same manner as in Experimental Example 1, except that a mixture of 20% by mass of sodium carboxymethylcellulose having a degree of etherification of 0.7 and 20% by mass of cold water-soluble polyvinyl alcohol having a saponification degree of 71% was used as the water-soluble binder. A piece was prepared and evaluated and is shown in FIG.

1 and FIG. 2, the molded articles prepared from the molding materials described in Experimental Examples 1 to 9 all start to disperse within 10 minutes when stirred in water, and have an area of about 50 mm ² or less within 15 minutes. It is obvious that the fragments having slashed into pieces and rapidly disperse in water. Further, the fluidity when filling the molding material into the mold and the releasability of the molded product from the mold are good, the molded product has no defects, and the surface property and strength of the molded product are good.

[Comparative Example 1]
Except that a mixture of corn starch 30% by mass and polyvinyl alcohol 10% by mass was used as the water-soluble binder, the amount of water added was 54 parts by mass, and the moisture content of the molding material was 45% by mass. Test pieces were prepared and evaluated, and are shown in FIG. A molded article made from the molding material according to Comparative Example 1 that does not contain carboxymethylcellulose salt in the water-soluble binder does not change in shape even when stirred in water for 60 minutes, and has rapid water dispersibility. There wasn't.

[Comparative Example 2]
A test piece was prepared and evaluated in the same manner as in Experimental Example 1 except that 40% by mass of cold water-soluble polyvinyl alcohol having a saponification degree of 71% was used as the water-soluble binder, and is shown in FIG. A molded article made from the molding material according to Comparative Example 2 that does not contain carboxymethylcellulose salt in the water-soluble binder does not change in shape even when stirred in water for 30 minutes, and gradually disperses after 30 minutes. Since it started, it did not have rapid water dispersibility.

[Comparative Example 3]
Test piece as in Experimental Example 1 except that the water-soluble binder was changed to carboxymethylcellulose sodium salt having a degree of etherification of 0.25, the amount of water added was 82 parts by mass, and the moisture content of the molding material was 45% by mass. This is shown in FIG. Although the molded article made from the molding material according to Comparative Example 3 using carboxymethyl cellulose salt having a low degree of etherification as the water-soluble binder has rapid water dispersibility, the molding material is filled in the mold. The fluidity was insufficient, and some of the molded products were damaged, making it difficult to produce stably.

[Comparative Example 4]
Except for blending 80% by weight of softwood bleached kraft pulp and 20% by weight of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder, the test piece was prepared and evaluated in the same manner as in Experimental Example 1, It was described in FIG. Although the molded article made from the molding material according to Comparative Example 4 in which the blending ratio of the carboxymethyl cellulose salt, which is a water-soluble binder, is low, has rapid water dispersibility, the flow when filling the molding material into the mold Insufficient property, insufficient strength of the molded product, and partial defects due to defective peeling due to this occurred, making it difficult to produce stably.

[Comparative Example 5]
Except for blending 20% by weight of softwood bleached kraft pulp and 80% by weight of carboxymethylcellulose sodium salt having a degree of etherification of 0.7 as a water-soluble binder, a test piece was prepared and evaluated in the same manner as in Experimental Example 1, It was described in FIG. Although the molded product produced from the molding material according to Comparative Example 5 having a high blending ratio of the carboxymethyl cellulose salt that is a water-soluble binder has rapid water dispersibility, the molded product surface has low smoothness, large depressions and The appearance was bad due to the uplift, which hindered actual use.

Claims (6)

A molding material made of natural fiber, water-soluble binder, water and a long-chain fatty acid salt of non-alkali metal, and used for molding injection-molded products or compression-molded products, 10 mm long, 10 mm wide, 1 mm thick molded flat plate A molding material characterized by having a water dispersibility that disperses into fragments having an area of about 50 mm ² or less within 15 minutes when it is poured into 300 ml of water and stirred at 650 rpm.   Made of natural fiber, water-soluble binder, water and non-alkali metal long-chain fatty acid salt, which is a molding material used for molding injection molded products or compression molded products, and carboxymethyl cellulose salt is adopted as water-soluble binder Molding material characterized by   The molding material according to any one of claims 1 and 2, wherein the water-soluble binder is a carboxymethyl cellulose salt, and a ratio of the natural fiber to the water-soluble binder is natural fiber: water-soluble binder = 75. ~ 30% by mass: Molding characterized in that 50 to 100 parts of water and 0.3 to 2.0 parts of non-alkali metal long-chain fatty acid salt are blended with 100 parts of a mixture of 25 to 70% by mass. material.   The molding material according to any one of claims 1 to 3, wherein the water-soluble binder is a carboxymethyl cellulose salt, and the carboxymethyl cellulose salt is an alkali metal salt having a degree of etherification of 0.5 to 1.0. A molding material characterized by that.   The molding material according to any one of claims 1 to 4, wherein 25 to 50% by mass of the carboxymethyl cellulose salt used as the water-soluble binder is replaced with cold water-soluble polyvinyl alcohol. .   A molded article obtained by injection molding or compression molding the molding material according to any one of claims 1 to 5.

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