JPH0577317A - Biodegradable synthetic paper - Google Patents

Abstract

PURPOSE:To provide a biodegradable synthetic paper having the same levels of strength, water resistance, bending strength and printability as those of the conventional paper and being biodegradable with microorganisms after disposal to avoid environmental pollution by drawing a crystalline and biodegradable polyester CONSTITUTION:A biodegradable polyester which is crystallizable as a raw material and wherein for example, 45wt.% 3-hydroxy-butylate-3-hydroxyvalerate copolmer contg. 10mole% hydroxy-valerate component and 55wt.% calcium carbonate as an inorg. filler are incorporated is drawn to prepare a synthetic paper. It is possible thus to obtain a synthetic paper with improved physical properties namely, with excellent dimensional stability, tensile strength, rigidity and heat resistance by drawing a crystalline and biodegradable polyester like this and after disposal, it is biodegradable by the action of micro-organism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic paper which is made of synthetic polymer and has paper-like properties.

[0002]

2. Description of the Related Art Conventional paper made of conventional pulp or the like has excellent printability and writability, and decomposes in the natural environment after disposal, but has weak strength, folding endurance, water resistance, etc. There was a problem. In addition, although synthetic paper made of polypropylene, polyethylene, polyethylene terephthalate, etc. is superior to natural paper in strength, water resistance, folding resistance, printability, writability, acid resistance and alkali resistance, it is not There was a problem that it did not decompose and damages the environment.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to provide the same strength, water resistance, and folding strength as conventional synthetic papers. Another object of the present invention is to provide a synthetic paper which has printability and writability and which, like natural paper, is biodegradable by microorganisms after disposal and does not pollute the environment.

[0004]

In order to solve this problem, the present invention provides a synthetic paper obtained by stretching a crystalline and biodegradable polyester.

The present invention will be described in detail below. The biodegradable polyester is melted by an extruder and extruded in a flat state from a die. The extruded film is stretched in the machine direction by utilizing the speed difference of the rolls. After that, both ends of the film are grasped with grips and stretched in the transverse direction while heating. After that, a well-known surface treatment is performed to turn the surface into paper.

The biodegradable polyester used in the present invention is poly-3-hydroxybutyrate, 3-hydroxybutyrate-3-hydroxyvalerate copolymer, 3-hydroxybutyrate-4-hydroxybutyrate copolymer,
3-Hydroxybutyrate-3-hydroxyvalerate-4-hydroxybutyrate terpolymer can be used.

Conventional extruders, dies, drawing machines, and coolers can be used to produce the biodegradable synthetic paper of the present invention. However, the extrusion temperature should be 170 to 200 ° C., and if it exceeds this temperature, the biodegradable polyester undergoes thermal decomposition, which is not preferable. Further, the stretching temperature is 70 to 120 ° C. in order to exert the stretching effect. Draw ratio is 2
~ 4 times.

A conventional method can be applied to give the film a paper-like property. For example, inorganic filler, foaming agent, pigment addition, or embossing roll compression, surface roughening by sandblasting, or corona discharge,
For example, the surface may be modified by treating with an oxidant or a chemical agent, or the surface may be made into paper by pigment coating or pulp coating.

[0009]

As described above, it is important that the synthetic paper according to the present invention is made of crystalline and biodegradable polyester and stretched. That is, the crystalline polyester is excellent in improving the physical properties by stretching, dimensional stability, tensile strength, rigidity, and heat resistance. Therefore, by stretching a crystalline and biodegradable polyester, a biodegradable synthetic paper excellent in dimensional stability, tensile strength, rigidity and heat resistance can be obtained.

[0010]

【Example】

<Example 1> As a biodegradable polyester, 3-hydroxybutyrate containing 10 mol% of a hydroxyvalerate component-
45% by weight of 3-hydroxyvalerate copolymer (Bottle molding grade of "Biopol" manufactured by ICI Japan Co., Ltd.) (hereinafter referred to as 3HB-3HV), calcium carbonate as an inorganic filler 55% by weight was used.

With the extruder "L / D28", the screw compression ratio was 3.0, the extrusion temperature was 170 ° C, the stretching temperature was 115 ° C,
Draw ratio 4 times, draw speed 3.0 m / min, average thickness 6
0 μm synthetic paper was molded.

<Example 2> As a biodegradable polyester,
3HB-3HV containing 10 mol% of hydroxyvalerate component
45% by weight. 55 calcium sulfate as an inorganic filler
Used by weight%.

With the extruder "L / D28", the screw compression ratio was 3.0, the extrusion temperature was 170 ° C, the stretching temperature was 115 ° C,
Draw ratio 4 times, draw speed 3.0 m / min, average thickness 6
0 μm synthetic paper was molded.

<Example 3> As a biodegradable polyester, 4% of 3HB-3HV containing 5 mol% of hydroxyvalerate was used.
5% by weight and 55% by weight of calcium carbonate were used as the inorganic filler.

With the extruder "L / D28", the screw compression ratio was 3.0, the extrusion temperature was 190 ° C, the stretching temperature was 115 ° C,
Draw ratio 4 times, draw speed 3.0 m / min, average thickness 6
0 μm synthetic paper was molded.

Comparative Example 1 Polypropylene was used as the film base material in an amount of 45% by weight, and calcium carbonate was used as an inorganic filler in an amount of 55% by weight.

With an extruder "L / D28", a screw compression ratio of 3.0, an extrusion temperature of 230 ° C, a stretching temperature of 150 ° C,
Draw ratio 4 times, draw speed 3.0 m / min, average thickness 6
0 μm synthetic paper was molded.

Data of these physical properties are shown in Table 1, and data of degradability are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

EFFECTS OF THE INVENTION According to the present invention, it has strength, water resistance, folding resistance, printability, essentiality, acid resistance, and alkali resistance equivalent to those of conventional synthetic papers, and after disposal, like natural papers. It is possible to obtain synthetic paper that is biodegradable by microorganisms and the like and does not pollute the environment.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tomoaki Takasaki 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (1)

[Claims] 1. A synthetic paper obtained by stretching a crystalline and biodegradable polyester.