JPH04367455A - Packaging material - Google Patents

Abstract

PURPOSE:To obtain the packaging material which retains the weatherability in use and may be buried under the ground after use to be decomposed to accelerate the degradation by forming the packaging material of the synthetic resin containing the substance decomposable under the ground to accelerate the degradation. CONSTITUTION:As a main material of packaging material, the synthetic resin containing the substance decomposable under the ground to accelerate the degradation is used. As such a decomposable substance, at least one kind of natural or synthetic high-molecular compound is used, preferably with metal salts added thereto. In this example, biodegradable substances 3 are provided scatteringly in the synthetic resin layer 2 constituting a major portion of the packaging material. With the passage of time after burying under the ground, the biological substances 3 are degraded and the places with the biodegradable substances present are also degraded, eventually fallen off from the synthetic resin layer and assimilated into the soil, resulting in the formation of a number of holes in the resin layer. Such holes become increasingly large to make the degradation of the synthetic resin layer 2 easy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to packaging materials whose deterioration is accelerated by rotting or decomposing in the soil.

0002

[Prior Art] It has been a long time since used and discarded synthetic resin products have been taken up as a pollution problem because they pollute the natural environment, but the disposal methods currently in use can be roughly divided into three types. . Namely, there are three methods: incineration, collection and reuse, and solidification and disposal.

[0003] However, each method has problems and is not a complete solution. Therefore, if left outside for a certain period of time, the best solution would be to turn it into a synthetic resin that naturally rots or decomposes like paper products or straw rope, and then molding products using this material. There was a time when a method of accelerating the photodeterioration of synthetic resins was considered as a measure for this purpose, and many proposals were made regarding this (see, for example, Japanese Patent Publication No. 50-27487).

0004

[Problems to be Solved by the Invention] However, when using these photodegradation acceleration methods, the photodegradation effect already progresses while the product is in use, and especially in the case of packaging materials that are frequently exposed and used outdoors, the photodegradation effect is severe. Become. Furthermore, even when products are kept in stock, this photodeterioration cannot be prevented unless light shielding measures are taken. In this way, even the best-of-breed products are limited in their usable period, and special considerations are required for storage.

Furthermore, in the case of the method of promoting photodeterioration, if the material is buried in soil or the like, the deterioration will not be accelerated because it will not receive light after that, and even if it is dumped, it will not be effective unless it is exposed. Since it cannot be obtained, it ends up being incinerated, which is not a complete solution as a disposal method. The present invention solves the above-mentioned drawbacks of the prior art, and particularly in the field of packaging materials, when used as a product, it has the same weather resistance as ordinary synthetic resin packaging materials, and therefore has sufficient strength as a product. It is possible to maintain the appearance, and when it is used, the packaging material is made of synthetic resin, which decomposes and accelerates deterioration when buried in the soil. The purpose is to provide

[0006]

[Means for Solving the Problems] The present inventors have found that in the field of synthetic resin products, such as packaging materials, which are frequently exposed to the outdoors and are required to maintain mechanical strength and appropriate appearance during use. The most appropriate synthetic resin product is one that decomposes and accelerates deterioration when placed in soil that is subject to active biological activity and slow physical or chemical influences. After thinking about it, I came to complete the present invention.

The gist of the invention set forth in claim 1 is a packaging material characterized in that it is molded from a synthetic resin containing a substance that decomposes in the soil and accelerates deterioration. The invention described in claim 1 is characterized in that the substance that decomposes in the soil and promotes deterioration is mainly a natural polymer compound or a synthetic polymer compound, and a metal salt is mixed therein. Its gist is packaging materials.

In the invention according to claim 1, the substances that decompose in the soil and promote deterioration (hereinafter referred to as "biodegradation promoting substances") include starch, cellulose, chitin, chitosan, and 3-hydroxybutyrate (abbreviation: 3HB). )-3 hydroxyvalerate (abbreviation: 3HV) copolymer, natural polymer compounds such as gluten, amylose, polyvinyl alcohol, polyamino acids, polycaprolactone, aliphatic polyesters, starch derivatives such as acetylation, esterification, etherification Alternatively, it refers to synthetic polymer compounds such as methylated starch, cellulose derivatives such as acetylated, esterified, etherified or methylated cellulose, and carboxymethyl cellulose, and one or more of these may be selected and used as appropriate.

[0009] When these biodegradation promoting substances are exposed to soil, they are decomposed by natural temperature, humidity, pressure, microorganisms, bacteria, small animals, and other elements existing in nature, and undergo chemical or biochemical reactions. Its molecular structure is broken and its quality changes. Furthermore, it falls off from the product due to slow physical or chemical influences in the natural environment. As a result, holes or cavities are formed in the product, making it porous and moth-eaten, and the synthetic resin layer continues to deteriorate under the above-mentioned effects of the natural world in the soil, accelerating decomposition.

[0010] In the invention as claimed in claim 1, the objective can be achieved simply by blending the biodegradation promoting substance into the synthetic resin, but in the invention as claimed in claim 2, the purpose is achieved by intentionally adding the biodegradation promoting substance to the synthetic resin to further promote its decomposition. , this biodegradation promoting substance is
The main ingredient is a natural or synthetic polymer compound, and a metal salt or the like is further mixed therein. In the invention according to claim 1 or 2, the blending ratio of the biodegradation promoting substance is usually 0.01 to 100 parts by weight of the synthetic resin.
It is added in an amount of 50 parts by weight, preferably 5 to 20 parts by weight. If the amount added is less than 0.01 parts by weight, the desired effect cannot be obtained, and if it exceeds 50 parts by weight,
The original properties of the synthetic resin cannot be maintained.

[0011] The above metal salts include zinc stearate,
Calcium stearate, Magnesium stearate,
Examples include calcium nitrate, calcium sulfate, calcium acetate, magnesium nitrate, magnesium sulfate, and magnesium acetate. The amount added is usually synthetic resin 1
The amount is 0.01 to 10 parts by weight per 00 parts by weight. The synthetic resin used in the invention according to claim 1 or 2 includes:
Various resins are used depending on the intended product, but general-purpose resins such as polyethylene, polypropylene, and polyester are often used.

[0012] Methods for producing synthetic resins containing biodegradation promoting substances include mixing predetermined amounts of biodegradation promoting substances, metal salts, etc. into these synthetic resins at the raw material stage, or When the synthetic resin is charged into the hopper of an extruder, injection molding machine, blow molding machine, or other synthetic resin molding machine, it may be mixed at the same time. As the synthetic resin containing the biodegradation accelerator, a conventionally known photodegradation accelerator may optionally be used in combination without departing from the object of the invention as set forth in claim 1 or 2.

[0013] The packaging material as used in the invention described in claim 1 or 2 refers to packaging supplies and packaging supplies used in the industrial field, distribution field, home, etc., and specifically includes films, sheets, containers, strings, and tapes. , ropes, nets, etc., and are manufactured using synthetic resin molding methods suitable for manufacturing each product.

[0014]

[Operation] The invention as claimed in claim 1 is a packaging material characterized by being molded from a synthetic resin containing a biodegradation promoting substance, so that during use, it has almost the same characteristics as general synthetic resin products. When used and exposed to soil, it is exposed to natural temperature, humidity, pressure, microorganisms, bacteria,
The biodegradation promoting substance is first broken down by chemical or biochemical reactions by small animals and other elements present in nature, its molecular structure is broken and its quality changes, and as a result, it falls off from the product. As a result, holes or cavities are formed in the product, resulting in a porous, moth-eaten state. The remaining synthetic resin layer continues to deteriorate under the above-mentioned influence of the natural world in the soil, and decomposition is accelerated.

[0015] The invention according to claim 2 uses a natural polymer compound or a synthetic polymer compound as the biodegradation accelerator, mixed with a metal salt, so that it does not decompose in the soil after use. , the progress of deterioration is further accelerated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The product shown in the drawing is an example of a so-called PP band that is commonly used for packaging cardboard boxes, etc. Figure 1 shows the product's appearance during storage, transportation, or use after shipment from the factory. FIG. 2 is a partially cutaway perspective view illustrating the used product, and FIG. 2 is a plan view illustrating the external appearance after a lapse of time when a used product is buried in soil for disposal.

In FIG. 1, 1 is a PP band, 2 is a main synthetic resin layer, and 3 is a biodegradable material scattered within this synthetic resin layer. When the product is being stored, transported, or used as a packaging material after being shipped from the factory, the shape of the product is almost the same as that of a conventional PP band. However, after being used and buried in the soil, as time passes, as shown in Figure 2, the areas where biodegradable materials were present will decompose and change in quality and fall off, becoming a component of the soil and forming bands. The body portion that was previously formed becomes a porous body, and the pores gradually become larger, and the synthetic resin layer 2, which is originally hard to deteriorate, becomes susceptible to deterioration. As more time passes, the synthetic resin layer 2 becomes individual fragments and small particles, and finally returns to soil and does not retain its shape at all.

Experimental Example 1 Starch (JIS
Three types of samples with 0, 5, 10, and 20 parts by weight of K 8658-78) added and a sample with no additive were prepared, and using these samples as raw materials, films with a thickness of 0.03 mm were each made by inflation. The tensile strength and elongation of each film obtained by molding were measured for those that were not buried in the soil and those that were taken out after being buried in the soil for 6 months. The results are shown in Table 1 for tensile strength and Table 2 for elongation.

[0019]

[Table 1]

[0020]

[Table 2]

Experimental Example 2 Cellulose (
KC flock manufactured by Sanyo Kokusaku Pulp) 0, 5, 10, 2
Three types of samples with each part by weight of 0.0 added and a sample with no additive were prepared, and these samples were used as raw materials to make each one with a thickness of 0.0.
A 3 mm film was molded using the inflation molding method, and the tensile strength and elongation rate of each film obtained were measured for those that were not buried in the soil and those that were taken out after being buried in the soil for 6 months. The results are shown in Table 3 for tensile strength and Table 4 for elongation.

[0022]

[Table 3]

[0023]

[Table 4]

Experimental Example 3 Polypropylene PP band prototype (width 15.5 mm,
0.5 mm thick), 100 parts by weight of polypropylene resin (manufactured by Chisso Petrochemical Co., Ltd.) as a raw material resin, and 0, 5, 10, and 20 parts by weight of starch (JIS K 8658-78) as a biodegradable substance. We prepared three types of samples with additives and a sample without additives, molded the above products using these samples as raw materials, and molded the resulting products into the soil for 6 months. After embedding, the sample was taken out and measured for breaking strength and elongation at break, and the results are shown in Table 5 for breaking strength and Table 6 for elongation.

[0025]

[Table 5]

[0026]

[Table 6]

[0027]

Effects of the Invention: The invention as claimed in claim 1 is a packaging material characterized by being molded from a synthetic resin containing a biodegradation accelerator, so that it is hardly different from a general synthetic resin product during use. When used and exposed to soil, it is exposed to the natural temperature, humidity, pressure, microorganisms,
As a result of chemical or biochemical reactions caused by bacteria, small animals, and other naturally occurring elements, the molecular structure of the biodegradation accelerator is first broken and altered, and as a result, it falls off from the product. As a result, the product becomes porous and moth-eaten, with holes or cavities forming. The remaining synthetic resin layer continues to deteriorate under the above-mentioned influence of the natural world in the soil, and decomposition is accelerated.

[0028] Therefore, since the photodegradation effect does not progress during the use of the product, there are no restrictions on its use. Further, there is no need to perform light shielding treatment while the product is in stock. Furthermore, if the material is buried in soil or the like, it will naturally decompose and deteriorate even if it is not exposed to light, and will not cause any pollution problems. The invention according to claim 2 uses a natural polymer compound or a synthetic polymer compound as the biodegradation accelerator, which is mixed with a metal salt, so that there is no decomposition or deterioration in the soil after use. Progress is further accelerated.

[0029] Therefore, the effects of the invention recited in claim 1 are further enhanced.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view illustrating the external appearance of the product during storage, transportation, and use after shipment from the factory.

FIG. 2 is a plan view illustrating the appearance of a used product after a period of time has elapsed after it was buried in soil.

[Explanation of symbols]

1 PP band 2 Synthetic resin layer 3. Biodegradable substances

Claims (2)

[Claims] 1. A packaging material characterized by being molded from a synthetic resin containing a substance that decomposes in the soil and accelerates deterioration. [Claim 2] A substance that decomposes in the soil and accelerates deterioration is
The packaging material according to claim 1, characterized in that the packaging material is mainly composed of a natural polymer compound or a synthetic polymer compound, and a metal salt is mixed therein.