JP3060184B2 - Plastic container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic container excellent in disintegration properties.

[0002]

2. Description of the Related Art Plastic containers have many excellent functions and conveniences, are widely used in the fields of foods, cosmetics, pharmaceuticals, etc., and the amount discarded after use is increasing year by year. Environmental pollution problems caused by container waste are increasing. There are methods for waste disposal of plastic containers, such as recycling, incineration, and landfilling.Incineration treatment generally involves high calories burned by plastics, and when incinerated, generates high heat or emits harmful gases. And cause environmental pollution problems. As a method for solving the above-mentioned problem, it has been proposed to add a large amount of non-combustible inorganic substances to plastics to reduce combustion calories as disclosed in JP-B-59-40695.

[0003]

However, even with the technology described in the above-mentioned publication, there is a limit in the incineration capacity, and it is not a drastic solution in the present situation where landfill accounts for the majority of waste disposal. Therefore, at present, naturally degradable resins that are decomposed and degraded with time under natural environments such as microorganisms in the soil and ultraviolet rays of sunlight are being developed. However, this naturally decomposable resin is not only disadvantageous in physical or chemical strength, but also expensive and expensive, because it forms a part that decomposes and disintegrates in the resin. Therefore , the fact is that it has not been widely used. The present invention is, naturally degradable resins, as a multi-layer structure obtained by laminating a resin having no spontaneous decomposition of having physical or chemical strength, are obtained as physical or chemical sufficient strength, yet The resin layer that does not have natural degradability is used as the intermediate layer, and the outer and inner layers are
Together they comprise a degradable resin, by laminating a layer specific thickness ratio of the resin having no natural degradability, container
In the composition, the layer of the naturally degradable resin is divided into an outer layer and an inner layer.
To reduce the thickness of the naturally decomposable resin layer
Naturally , the surface area of the decomposable resin layer is almost doubled, and the natural decomposability function is greatly improved.
Ruue, also have the desired physical or chemical properties
Despite the fact that the function of spontaneous decomposition is large and short
An object of the present invention is to provide a plastic container that can be decomposed and disintegrated between the materials, and that is adapted to the above-mentioned effects on nature and the environment.

[0004] Further, the present invention has excellent layer comprising an oxygen barrier resin in barrier property by the intermediate layer and be Rukoto, moreover influence on the nature described above, and aims to provide a plastic container adapted to the environment Is what you do.

[0005]

Means for Solving the Problems The present invention is constituted as follows as technical means for achieving the above object. That is, the plastic container according to the present invention is a multi-layer plastic container composed of a layer made of a naturally degradable resin and a layer made of a resin having no spontaneous degradability,
A layer made of a resin that does not have spontaneous degradability is used as an intermediate layer.
The outer and inner layers are composed of layers composed of naturally decomposable resin.
Form, tensile modulus resin having no natural degradable constituting the intermediate layer is a 4000 kg / cm ² or more resins, outer
The layer composed of the naturally decomposable resin constituting the layer and the inner layer has a thickness of 80% or more of the whole. In the plastic container according to the present invention, the intermediate layer made of a resin having no spontaneous degradability has an oxygen permeability coefficient of 1 × 10 ⁻¹¹ cc.
Cm / cm ² · sec · cmHg (37 ° C, RH.
0%) or less.

[0006]

The plastic container according to the present invention is naturally degradable.
A layer made of a resin having no resin as an intermediate layer, and an outer layer thereof
And inner layer from a multilayer structure composed of a layer made of natural decomposable resin, the plastic container is naturally degradable tree
The fat layer is dispersed in the outer and inner layers to
The thickness of the layer is reduced, and the layer
The area is approximately doubled. Because of this, naturally degradable
Is greatly improved , and is decomposed and broken down over time in a short period of time by natural environments such as microorganisms in the soil and ultraviolet rays of sunlight.

Further, the plastic container according to the present invention comprises:
Since the structure is such that the resin layer having no spontaneous decomposition is used as the intermediate layer, and the spontaneous decomposable resin layer is used as the outer layer and the inner layer , the spontaneous decomposition function is extremely large as described above.
Nevertheless , desired physical or chemical properties can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described.
The plastic container according to the present invention has a multilayer structure of three or more layers. The outer layer and the inner layer are made of a naturally decomposable resin, and the intermediate layer is made of a resin having no spontaneous decomposability. Hereinafter, specific examples of the resin constituting the plastic container according to the present invention will be described. (Naturally degradable resin) Naturally degradable resin is a general term for resins that are decomposed and disintegrated over time under the natural environment such as microorganisms in the soil and ultraviolet rays of sunlight. It refers to a mixture of 10% by weight or more with another synthetic resin. (1) Addition of photodecomposition agent The photodecomposition agent is a mixture of a photosensitizer such as ketones and anthraquinones, a mixture of a transition metal salt of dithiocarbamic acid and a cerium-based transition metal compound, Mixtures of compounds having unsaturated bonds of olefins and terpenes, mixtures of halogen compounds, compounds which generate radicals by photodecomposition of halides, and others (-C =
A compound having an N-) bond corresponds to the compound, and by adding this photolytic agent to the resin, the resin itself is decomposed and broken down by light with time. (2) Synthesizing a polymer having a photodecomposable group A polymer having a photodecomposable group is a polymer having a ketone structure such as a CO copolymer or a vinyl ketone copolymer, a polymer having an unsaturated bond, or other polymer oxidized by light. A polymer having the photodecomposable group is synthesized, and the polymer itself is decomposed and degraded with time from the portion of the photodecomposable group. (3) Natural polymer The natural polymer is a plant-based polymer such as cellulose, lignin or starch, or an animal-based natural polymer such as chitin. It is decomposed and broken down with time by microorganisms in the soil. (4) Microorganism-producing polymer As the name implies, a microorganism-producing polymer is a substance that produces a substance having a plastic-like function by utilizing a polymer produced by a microorganism. Microorganisms generally store energy in the form of polyesters shown below in the form of granules. When energy is required, the energy is decomposed by a decomposing enzyme within the microorganism to take out the energy. Therefore, this polyester is easily decomposed and disintegrated with the lapse of time by a microorganism-decomposing enzyme in soil or the like.

Embedded image (5) Biochemical high-molecular-weight biodegradable aliphatic polyesters, amino acids and sugars are produced by fermentation technology and copolymerized with polyethylene, polypropylene, etc. to decompose microorganisms in the soil It is easily decomposed and broken down by enzymes over time. (6) What added a biodegradable substance A biodegradable substance is a saccharide such as corn starch, and by adding this biodegradable substance to a resin,
The resin itself is decomposed and disintegrated with time by microorganisms such as soil. (Non-degradable resin) Non-degradable resin is a general term for resins that are not easily degraded or disintegrated with time in the natural environment such as microorganisms in the soil or ultraviolet rays of sunlight. Is a resin having physical or chemical properties that does not have Specifically, polyolefins such as polyethylene and polypropylene, modified polyolefins obtained by modifying polyolefins with unsaturated carboxylic acids or anhydrides, polyethylene terephthalate, polyethylene isophthalate, polyethylene 2,6-naphthalate, polybutylene terephthalate, and copolymers thereof Polyester resins such as polyester resins represented by coalescence, polyether resins represented by polyoxymethylene, polyamide resins represented by nylon-6, nylon 66, polymethaxylene adipamide, polystyrene, poly (Meth) acrylic esters, polyacrylonitrile, vinyl resins such as polyvinyl alcohol and saponified ethylene-vinyl acetate copolymer, polycarbonate resins, cellophane, Cellulose-based resins such as acetate, as well as resins generally referred to as engineering plastics such as polyimide, polyethersulfone, polysulfone, polyetheretherketone, polyetherketoneketone, and many other resins , Copolymers, mixtures, composites and the like. Among these, the resin having no spontaneous degradability according to the present invention refers to a resin having a tensile modulus of 4000 kg / cm.
² or more, preferably 6000 Kg / cm ² or more. When a plurality of resin layers having no natural degradability are provided, the tensile elastic modulus of the non-naturally decomposable resin constituting each layer is a value obtained by distributing the tensile elastic modulus among the respective thicknesses. Among these resins having no spontaneous decomposability, an oxygen barrier resin has an oxygen permeability coefficient of 1 × 1
0 ^-11 cc · cm / cm ² · sec · cmHg (37 ° C,
R. H. 0%) oxygen barrier resin, for example, polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer, polyamide-based resin, and a modified product thereof or a mixture mainly containing them.

The plastic container according to the present invention comprises seasonings, edible oils, fruits, vegetables, cooked foods, foods such as soups, jams, fruit drinks, creams, cosmetics such as liquid hair styling agents, blood and plasma substitute liquids. And packaging containers such as bottles, tubes, cups, bags, and bags for storing pharmaceuticals such as infusions, other liquids, viscous materials, and powders.

[0010] The plastic container of the present invention is blow molded,
A multi-layer molding method such as injection molding, extrusion molding, vacuum molding, or pressure molding can be used as appropriate.

Representative examples of the layer structure of the plastic container of the present invention are shown below. (1) 3-layer structure DP / N / D P DP / NB / DP (2) 5 -layer structure DP / N / DP / N / DP DP / NA / ND / NA / DP (3) 7 -layer structure DP / N / NA / NB / NA / N / DP In the above configuration example, DP is a naturally decomposable resin, N is a resin having no spontaneous decomposability, NA is a resin having an adhesive property, and NB is a resin having an oxygen barrier property. Is abbreviated as a layer consisting of: In the present invention, the thickness of the naturally decomposable resin layer is at least 80% or more, preferably 90% or more.

(Examples 1 and 2, Test Examples 1 and 2 , Comparative Example 1
3) A food bottle 1 having a content of 500 cc shown in FIG.
(Thickness unit μ). FIG. 2 shows a five-layer structure. 2 is an outer layer, 3 is an inner layer, 4 is an intermediate layer, and 5 is an adhesive layer.

[Table 1] In Table 1, PE (light), PE (soil), PE (1), PE
(2) Adhesive and EVOH refer to the following. PE (light): NUCL2910 manufactured by Nippon Unicar, which is a synthesis of a polymer having a ketone structure PE (soil): IC composed of a microorganism-producing polymer
Company I Biopol PE (1): High density polyethylene (tensile modulus: 450
0Kg / cm ² ) PE (2): high density polyethylene (tensile modulus: 350
0Kg / cm ² ) Adhesive: modified polyolefin resin (tensile elastic modulus: 1)
500 kg / cm ² ) EVOH: ethylene content 29 mol%, saponification degree 99
% Or more of the saponified ethylene-vinyl acetate copolymer (tensile elastic modulus: 21000 Kg / cm ² ). The containers obtained in Example 1 , Test Examples 1 and 2 and Comparative Examples 1 to 3 were exposed outdoors. The tensile modulus and elongation were measured by a tensile test before and 45 days and 90 days after the exposure test, respectively.
It was shown to. The tensile test was conducted according to JIS K71 from the container.
In accordance with the standard of No.13, two test pieces were cut and prepared, and 5
It is measured at a tensile speed of 0 mm / min.

[Table 2] Further, the containers obtained in Example 2 and Comparative Example 1 were buried in soil, respectively, and a tensile test was performed to measure tensile strength and tensile modulus. Table 3 shows the results.

[Table 3] From Example 1 and Test Examples 1 and 2 , it was found that those having 80% or more of the layer of the naturally decomposable resin had lower elongation in the tensile test. In particular , those of Example 1
By outdoor exposure of 5 days next to the elongation of 8.7%, trial
15% for Test Example 1 and 13% for Test Example 2
Compared extremely seen that reduction progresses, and readily disintegrate by pressing by hand. By burying in the soil, the tensile strength was reduced by 50% in 90 days from Example 2 and Comparative Example 1. However, in the case of Comparative Example 1, no decrease in tensile strength was observed. As a result of measuring the oxygen permeability at 30 ° C. and 50% RH, Examples 1 and 2 were obtained.
In both cases, a high oxygen barrier property of 0.3 cc / m ² · 24 hr was obtained.

[0013]

According to the present invention, as described in claim 1 ,
Naturally degradable resin has physical or chemical strength
Multi-layer structure with resin that does not have natural degradability
And have sufficient strength physically or chemically.
In addition, a resin layer that does not have natural degradability
And the outer and inner layers are composed of naturally degradable resin
In both cases, the resin layer that does not have spontaneous degradability is
Decomposes naturally in container configuration
Disperse resin layer into outer layer and inner layer
The thickness of the layer of natural degradable resin
Approximately double the product to greatly improve natural degradability
Is decomposed and disintegrated in a short period of time, and
Or even though it has chemical properties
Naturally degradable function can be decomposed and collapsed in a short time
Thus, a plastic container adapted to the above-mentioned effects on nature and the environment can be obtained.

Furthermore, the present invention includes a set forth in claim 2
Cage, excellent layer comprising an oxygen barrier resin in barrier property by the intermediate layer and be Rukoto, moreover influence on the nature described above,
A plastic container suitable for the environment can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a plastic container according to the present invention.

FIG. 2 is a cross-sectional view showing a five-layer structure in which a portion surrounded by a broken-line circle in FIG. 1 is enlarged.

[Explanation of symbols]

 Reference Signs List 1 food bottle 2 outer layer 3 inner layer 4 intermediate layer 5 adhesive layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-209144 (JP, A) JP-A-4-72137 (JP, A) JP-A-4-90339 (JP, A) JP-A 48-108 100440 (JP, A) JP-A-4-299131 (JP, A) JP-A-48-1081 (JP, A) JP-A-50-86543 (JP, A) JP-A-4-311451 (JP, A) JP-A-4-311460 (JP, A) JP-A-4-298335 (JP, A) JP-A-4-298336 (JP, A) Japanese Translation of PCT Application No. 5-505354 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 1/00-1/48

Claims (2)

(57) [Claims] 1. A plastic container having a multilayer structure composed of a layer made of a naturally degradable resin and a layer made of a resin having no spontaneous degradability.
Layer as an intermediate layer, and its outer and inner layers
The resin composed of a layer made of a degradable resin and having no spontaneous degradability constituting the intermediate layer has a tensile modulus of 4000 Kg / c.
A plastic container characterized by having a thickness of at least 80% of the total thickness of a layer composed of a naturally decomposable resin, which is a resin of m ² or more and constitutes an outer layer and an inner layer. 2. An intermediate layer made of a resin having no spontaneous decomposability has an oxygen permeability coefficient of 1 × 10 ⁻¹¹ cc · cm / cm ^2.
2. The plastic container according to claim 1, further comprising a layer of an oxygen barrier resin having a value of sec · cmHg (37 ° C., RH 0%) or less.