JPH10298311A - Degradable embossed film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject film easy in disposed due to being soluble in water and low in combustion calorie, by using a polyvinyl alcohol as a synthetic resin to provide a base resin of an embossed film having a great number of projected parts. SOLUTION: A polyvinyl alcohol is used as a synthetic resin to provide an embossed film 1 having a great number of projected parts 2. The polyvinyl alcohol has preferably 300-800 polymerization degree and >=86% saponification degree and a modified polyvinyl alcohol containing 25-60% hydrophilic group such as carboxyl group is preferable. A polyvinyl alcohol containing 0.3-10 % of a plasticizer (e.g. glycerol) is preferable. Optionally a liner film may be stuck to the surface of the projected parts 2 of the embossed film 1. The embossed film 1 is useful as an eliminable spacer for a protecting material, a curing material, a mold for molding, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decomposable embossed film which is easily used in post-treatment and is used for protective materials, curing materials, spacers and the like.

[0002]

[Prior art]

Conventionally, paper or synthetic resin sheets, synthetic resin foams, or the like have been used singly or in combination for protection of objects and curing of buildings.

A sheet made of the synthetic resin as a raw material is not decomposed even when buried in the soil, and its form is left semipermanently. In addition, the same thing can be said for those using paper as a raw material, since most of them have a surface laminated with a synthetic resin for reinforcement.

As a means for solving these problems, a method of kneading a decomposable substance such as starch into a synthetic resin as a raw material has been considered. However, even with such a method, the main raw material is a synthetic resin. Since only the starch portion is removed, it is difficult to discriminate the morphology with the naked eye, and it is difficult to say that it has true degradability. Also, the improvement of materials alone did not solve the problem of volume reduction.

[0006]

[Problems to be solved by the invention]

Therefore, the inventors have concluded that a material having more excellent degradability has the following properties. When buried in soil, it is broken down by microorganisms. What can be decomposed without depending on microorganisms when buried in the soil. What can be decomposed in the everyday environment, not only in the soil.

[0008]

The present inventors have selected water-soluble synthetic resins, particularly polyvinyl alcohol, as the main raw materials having the above properties and the above properties. The shape and properties will be described with reference to FIGS.

[0009]

FIG.

FIG. 1 is a perspective view of an embossed film according to an embodiment of the present invention, wherein 1 is the embossed film of the present invention, 2 is a convex portion, D is the diameter of the convex portion, and H is the height of the convex portion. is there. Because of the rigidity and restoring force of the film on the side wall of the convex portion obtained by forming the film with the irregularities in this manner,
Has a certain buffering effect.

The projection 2 shown in FIG. 1 is a cylinder having a general shape, and the height H of the projection is in the range of 2 to 20 mm, and the diameter D of the projection is in the range of 3 to 50 mm. However, the shape of the embossed film of the present invention is not limited to this. For example, the shape of the convex portion 2 may be larger, and the shape may be a rectangular parallelepiped or the like. I don't care.

[0012]

FIG. 2

Further, as shown in FIG. 2, the embossed film of the present invention may be a two-layer product in which a liner film 3 is adhered to the top of an embossed film 1 having a large number of projections.

The material of the embossed film of the present invention includes:
As described above, polyvinyl alcohol is used as a synthetic resin as a base resin. Polyvinyl alcohol has a large number of hydroxyl groups in its molecule and can be easily dissolved in water. Therefore, when buried in soil, it is easily dissolved by the moisture. Further, since it has the property of being dissolved in water even in the soil, it can be easily post-treated. In addition, the burning calories are 11,000 kcal /
g, which is as low as 6,000 kcal / g compared to 10,500 kcal / g of polypropylene, which is about half that of the conventional polyolefin resin, so that it can be easily burned and treated.

The polyvinyl alcohol is obtained by saponifying vinyl acetate, and the saponified acetate group of 99% or more is called a completely saponified product, and the polyvinyl alcohol up to about 86% is called a partially saponified product. Completely saponified compounds dissolve when left in water for a long time or are poured into boiling water, but do not dissolve quickly in cold water. Up to a saponification degree of about 86%, the degree of saponification decreases and polyvinyl alcohol becomes easily soluble in water. However, when the saponification degree is lower than about 86%, the content of residual vinyl acetate increases, so that the decomposability decreases. As a result, residual components are left. Further, when the partially saponified product comes into contact with an alkaline substance, the saponification reaction of the remaining acetate group proceeds, and the rapid solubility in cold water is lost. From this, it is necessary that the polyvinyl alcohol used in the embossed film of the present invention has a saponification degree of 86% or more, preferably 95% or more, and more preferably 99% or more. If the saponification degree is 86% or less, it is not preferable because it becomes too soluble in water, which makes it difficult to handle and store as an embossed film, degrades the decomposability, and lowers the objective function of the present invention. .

However, the higher the degree of saponification of polyvinyl alcohol, the higher the rigidity of the film at the time of forming the film, the narrower the range from the melting point to the glass transition point, and the more severe the temperature conditions of the thermoforming. Extreme difficulty. In such a case, to improve the physical properties, a carboxyl group,
Modified polyvinyl alcohols such as silanol groups and cations are known. For example, Japanese Unexamined Patent Publication (Kokai) No. 63-25021 discloses a polyvinyl alcohol which is completely saponified and is blended with 5 to 20% of a soluble amide and is soluble in cold water and has alkali resistance.
No. 0888 is obtained by reacting a polyalkylene glycol compound obtained by addition-polymerizing an alkylene oxide containing an ethylene compound with an organic compound having two active hydrogen groups and a divalent carboxylic acid, an anhydride thereof or a lower alkyl ester thereof. There is a disclosure of a film base made of a water-soluble polymer obtained, and this film is based on a water-soluble film despite its solubility in water being 3 to 5 times faster than a conventional water-soluble film. Low moisture absorption compared to JP-A-6-179235 discloses an extrudable alkylene group-containing polyvinyl alcohol obtained by copolymerizing oxyalkylene monoallyl ether having an average degree of condensation of oxyalkylene of 10 with vinyl acetate and then saponifying with an alkali. is there. The inventors of the present invention have made further studies and found that modified polyvinyl alcohol having 25% to 60% of a hydrophilic group such as a carboxyl group has high water solubility, high continuous thermoformability and processability despite low moisture absorption. I came to the conclusion. If the content of the hydrophilic group is 25% or less, no remarkable improvement is observed as compared with polyvinyl alcohol alone. Also, those with 60% or more are difficult to manufacture with current technology.

The modified embossed polyvinyl alcohol alone may be formed and formed to produce the embossed film of the present invention. However, the water content of polyvinyl alcohol varies depending on the surrounding environment. In an environment of high temperature or low humidity, the rigidity increases, which may hinder secondary processing such as manufacturing or cutting. As a countermeasure, it is necessary to reduce the rigidity of the formed film itself and increase the flexibility.

In such a case, various problems can be solved by lowering the rigidity by adding a plasticizer preferably in the range of 0.3% to 10%, more preferably in the range of 0.5% to 5%. . DOP, DBP and the like can be considered as the plasticizer, but glycerin is particularly preferably used. If the added amount is less than 0.3%, the effect of adding the plasticizer does not appear, and if added more than 10%, the physical properties of polyvinyl alcohol itself deteriorates,
When heated, glycerin vaporized significantly generates smoke, which hinders film formation and molding.

Polyvinyl alcohol itself has a maximum of 1
Although there are those having a degree of polymerization of 500 or more, those having a degree of polymerization of about 800 to 300 are suitable for the embossed film of the present invention. Extrusion molding is difficult for those having a degree of polymerization of 800 or more because of high melt viscosity, and those having a degree of polymerization of 300 or less are not particularly problematic during extrusion molding. The strength drops extremely.

The decomposable embossed film of the present invention composed of such a material is a protective material and a curing material which are extremely excellent in terms of post-processing, and is a model for molding which is conventionally frequently used with wax. It is also effective to use it as a disappearing spacer. If you use wax,
Heat must be applied to the base material when removing the mold,
It was necessary to provide an outlet for the melted wax. However, if the base material is washed with water if the decomposable embossed sheet of the present invention is used, since the mold is dissolved in water and flows out from a small gap in the base material, the heat resistance of the base material is lower than that of wax. In this case, it can also be used for applications in which the wax dissolved in the base material permeates.

The embossed film of the present invention uses polyvinyl alcohol as a synthetic resin as a base resin of the material. Since polyvinyl alcohol has many hydroxyl groups having hydrophilicity in its molecule, it can be easily dissolved in water. Therefore, when buried in soil, it is easily dissolved by its moisture. Further, since it has the property of being dissolved in water even in the soil, it can be easily post-treated. In particular, the inventors of the present invention have conducted intensive studies and found that a modified polyvinyl alcohol having 25% to 50% of a hydrophilic group such as a carboxyl group has high water solubility, high continuous thermoformability and processability despite low hygroscopicity. I came to the conclusion. In addition, the modified emulsified polyvinyl alcohol alone may be formed and formed to produce the embossed film of the present invention, but due to its properties, the water content of polyvinyl alcohol decreases when heated in film formation and the like, and the rigidity decreases. Due to the increase in the thickness, there is a possibility that secondary processing such as film formation, molding, taking over, or cutting may be hindered depending on the film thickness and operating conditions. In such a case, various problems can be solved by lowering the rigidity by adding a plasticizer. The decomposable embossed film of the present invention composed of such a material is a very excellent protective material and curing material from the viewpoint of post-processing, and also disappears a model for molding, which is conventionally used frequently with wax. It is also effective to use it as a spacer. If wax is used, heat must be applied to the base material when the mold is removed, and a discharge port for the melted wax must be provided. However, if the base material is washed with water if the decomposable embossed sheet of the present invention is used, since the mold is dissolved in water and flows out from a small gap in the base material, the heat resistance of the base material is lower than that of wax. In this case, it can also be used for applications in which the wax dissolved in the base material permeates.

[0021]

The height H of the projections was 4 mm and the diameter D of the projections was 10
mm embossed film was obtained. The material was a modified polyvinyl alcohol having a polymerization degree of 700 containing 40% of a carboxyl group as a hydrophilic group and weighing 100 g / m 2.

[0022]

[Comparative Example] Height of convex part H = 4 mm, diameter D of convex part = 10
mm embossed film was obtained. The material was polyethylene and the weight was 100 g / m 2.

[0023]

[Disassembly test] Both buried in soil, 1 month, 3 months, 6
A month later, the state of decomposition was confirmed.

[0024]

[Test Results] The embossed film of the present invention in Examples was decomposed so as to almost lose the form of the embossed film one month after embedding, and completely disappeared after three months. On the contrary, the conventional embossed film of the comparative example keeps its form completely during the test period,
No decomposition was performed.

[0024]

[Effect] The embossed film of the present invention has a large number of hydroxyl groups in a molecule of polyvinyl alcohol as a main raw material,
It is water soluble. For this reason, even when buried in the soil, the decomposition is performed more stably than a synthetic resin that decomposes by microorganisms. Further, by using polyvinyl alcohol as a modified polyvinyl alcohol containing a hydrophilic group such as a carboxyl group, low moisture absorption, high water solubility, high continuous thermoformability and workability can be realized. In addition, by using polyvinyl alcohol as the material, it has become possible to reduce the calorie of combustion to about half that of the conventional polyolefin resin. Further, during storage and disposal when not in use, unlike the conventional bubble sheet, since there is no air layer, the volume can be easily reduced. In addition, since it is water-soluble, it is also effective to use it as a disappearing spacer for a model for molding, for example, in which wax is conventionally frequently used. In this case, it can also be used in cases where the conventional wax cannot be used, when the heat resistance of the base material is lower than that of the wax, or where the wax dissolved in the base material permeates.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the embossed film of the present invention.

FIG. 2 is a perspective view of another embodiment of the embossed film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Embossed film 2 Convex part 3 Liner film D Diameter of convex part H Height of convex part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B29K 29:00 B29L 7:00

Claims (6)

[Claims] 1. An embossed film having a large number of projections, wherein the main material is polyvinyl alcohol. 2. The embossed film according to claim 1, wherein another flat liner film is adhered to the surface of the convex portion of the embossed film. 3. The polymerization degree of the polyvinyl alcohol is 3
3. The embossed film according to claim 1, wherein the embossed film has a range of from 00 to 800 and a degree of saponification of from 86% to 100%. 4. The embossed film according to claim 1, wherein the polyvinyl alcohol is a modified polyvinyl alcohol containing a hydrophilic group such as a carboxyl group in a range of 25% to 60%. 5. The embossed film according to claim 1, wherein 0.3 to 10% of a plasticizer is added to said polyvinyl alcohol. 6. The embossed film according to claim 5, wherein said plasticizer is glycerin.