JP2830680B2 - Plastic paper containers - 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 paper container, and more particularly to a plastic paper container having heat resistance and water resistance for food use and having complete biodegradability.

[0002]

2. Description of the Related Art Conventionally used plastic paper containers have rigidity and impact resistance required for the container, as well as a function of preventing leakage of contents, a function of maintaining hygiene of contents, a function of heat sealing and sealing, and the like. Therefore, paper and a polyolefin such as polyethylene and polypropylene are laminated as a coating layer and a sealant layer.

When the plastic paper container is discarded after use, if it is landfilled or scattered as garbage in the natural environment, the polyolefin remains as it is without being decomposed. This may shorten the life of the treatment plant and cause environmental pollution.

The above problem can be solved by making the plastic laminated on the paper also biodegradable.
The present inventors have also proposed a laminate that can be used for such a paper container in Japanese Patent Application No. 3-249106. But now,
Many biodegradable plastics are known, but all have different physical properties from conventionally used polyolefins, and a single-layered paper container cannot provide a paper container with sufficient performance.

For example, paper and 3-hydroxybutyric acid-3-
Hydroxyvaleric acid copolymer (hereinafter P (3HB-3HV)
The paper container formed of the laminate of the above has insufficient lamination strength and water resistance as compared with that of paper and polyethylene, and paper and poly ε-caprolactone (hereinafter referred to as PCL).
The paper container made of the laminate of the above is insufficient in heat resistance.

[0006] As described above, paper containers which can be used for food applications, satisfy all of the functions of preventing leakage of contents, maintaining the hygiene of contents, and sealing and sealing by heat, and having complete biodegradability are still available. Not developed.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to be used for food applications, to prevent leakage of contents.
It is a plastic paper container that satisfies all the functions of maintaining the hygiene of the contents and the function of heat sealing and sealing.
An object of the present invention is to provide a plastic paper container characterized by using a biodegradable plastic, which is completely decomposed by the action of microorganisms even when scattered as garbage in the natural environment.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a plastic paper container made of a laminate of paper and plastic, wherein P (3HB-3HV) is applied to paper through an adhesive layer made of PCL. The present invention provides a plastic paper container comprising a laminate provided with a surface layer. The present invention also provides a plastic paper container, wherein the adhesive layer made of PCL is a mixture of PCL and another biodegradable plastic, and the content of PCL is 50% by weight or more.

Hereinafter, the present invention will be described in detail. FIG. 1 shows an embodiment of the configuration of the plastic paper container of the present invention. For the surface layer 1, P (3HB-3HV) is used.

This is because the surface layer in the container places the highest importance on the function of maintaining hygiene, and P (3HB-3HV), which is a microorganism-produced polyester, can be regarded as a natural material similar to paper. This is because there is no problem in hygiene. PCL, on the other hand, has a melting point of 60 (° C.) and a softening point of 50 (° C.). Further, a chemically synthesized product such as PCL contains an oligomer and a monomer, and these may be eluted, but the sanitary property at that time has not been confirmed.

The adhesive layer 2 is made of PCL or a mixture of PCL and another biodegradable plastic having a PCL content of 50% by weight or more.

This does not mean that P (3HB-3HV) in the surface layer does not adhere to the paper at all, but the laminate strength is weaker than other plastics, and there is a possibility that it will peel off when used as a paper container. Because there is. Further, it is difficult to have water resistance, and when the contents containing a large amount of water are filled, cracks may be generated and the water may leak out of the container.

As the biodegradable plastic that can be used for mixing with the PCL, any plastic can be used as long as it has a biodegradability equal to or higher than that of paper. For example, microorganisms such as P (3HB-3HV) can be used. Produced polyesters, aliphatic polyesters similar to PCL, polyglycolides such as polylactic acid, polyvinyl alcohol, polyvinyl alcohol starch composites and the like can be used, and even a mixture of these biodegradable plastics can be used. good. These have a weight ratio of PCL of 50% or more in terms of adhesion to paper and water resistance.

The paper 3 may be paper used in a normal paper container.

The method of laminating the biodegradable plastic and paper in the present invention may be a method used in the production of ordinary plastic laminated paper, such as lamination (lamination) of a plastic film on paper or melting of plastic on paper. Lamination can be performed by a method such as extrusion coating, but from the viewpoint of efficiency, melt extrusion coating by coextrusion is desirable.

Processing of a plastic laminated paper made of biodegradable plastic and paper into a plastic paper container can be performed by a conventional method, for example, using an apparatus such as a punching machine, a sack sticking machine, or a box making machine.

[0017]

As described above, in the present invention, the plastic to be laminated on paper is made of P (3HB-3HV), which has no problem in heat resistance and hygiene, for the surface layer,
By using PCL with excellent water resistance or a mixture of PCL and other biodegradable plastics, it can be used for food applications, preventing leakage of contents, maintaining hygiene of contents, and sealing by heat sealing. Is satisfied, and a plastic paper container having complete biodegradability is obtained.

[0018]

【Example】

<Example 1> using a paperboard having a basis weight of 350 g / m ² as a paper, so that the adhesive layer PCL (Union Carbide Bird Chemical Co. (USA): "TONE P-767")
To a thickness of 15 μm and P (3HB-
3HV) (manufactured by ICI (UK): “Biopole (HV)
The content was 15%)), and was co-extruded with a multi-manifold type co-extruder to a thickness of 15 µm and laminated.

The above configuration (paperboard / PCL / P (3HB-
3HV)) was punched into a shape as shown in FIG. 2 by a punching machine, and was box-formed so that the paper came to the outside as shown in FIG.

<Example 2> Instead of the PCL of Example 1, a mixture of PCL and P (3HB-3HV) (weight ratio of 75) was used.
%: 25%) in the same manner as in Example 1.

<Example 3> The procedure of Example 2 was repeated except that the weight ratio of PCL was 50% and P (3HB-3HV) was 50%.

<Comparative Example 1> PCL and P of Example 1
In the same manner as above (3HB-3HV), punching was performed using laminated paper in which polyethylene of 20 μm was laminated, and the box was produced.

<Comparative Example 2> A 30 μm PCL (“TONE P-767” manufactured by Union Carbourd Chemical Company (USA)) was laminated in place of the polyethylene of Comparative Example 1 and punched in the same manner. I made it.

Comparative Example 3 A laminated paper obtained by laminating 30 μm of P (3HB-3HV) (manufactured by ICI (UK): “Biopol (HV content: 15%)) instead of polyethylene of Comparative Example 1 was used. It was similarly punched and used to make a box.

<Comparative Example 4> The procedure of Example 2 was repeated except that the weight ratio of PCL was 25% and P (3HB-3HV) was 75%.

The heat resistance, laminate strength, water resistance and degradability of the plastic paper container thus prepared were measured by the following methods.

<Heat resistance> Put boiled beans in a container, wrap it with a polyvinylidene chloride film, and heat at 50 ° C and 25% RH.
After 3 days storage under the environment, the surface condition is visually observed,
When there was a clear change, it was marked as x, and when there was no change, it was marked as o.

<Lamination Strength> A rectangular test piece having a width of 15 mm was cut out from the container, and the force required for peeling the paperboard from the laminated plastic was measured using a tensile tester.

<Water resistance> A gauze soaked in water is placed in a container and wrapped with a polyvinylidene chloride film.
After storage for 5 days in an environment of 60 ° C. and 60% RH, gauze was removed, and water leakage was checked visually and with turpentine oil. × indicates that there is a clear leak visually, 微小 indicates that no pinholes and cracks are observed with turpentine oil application, but 変 化 indicates that there is no leakage even with turpentine oil application. And

<Degradability> The activated sludge tank of the wastewater treatment plant is wrapped in a net made of polyvinyl chloride and hung. The state of decomposition is periodically evaluated. What was stopped was marked as x.

[0031]

[Table 1]

In Table 1, in the column of the lamination strength, the term "paper waste" means that the paperboard and the laminated plastic cannot be peeled off, and if the paperboard is forcibly peeled off, it peels between the fibers of the paperboard. This indicates that the adhesion between the two is stronger.

From Table 1, it can be seen that, even when the plastic layer was made of polyethylene alone, the paper absorbed water and loosened the fibers even after immersion in the activated sludge layer for one month (Comparative Example 1).

The plastic layer is made of P (3HB-3H).
V) In the case of a simple substance, water leakage was apparently visually observed in the water resistance evaluation. The lamination strength is 200g
It was f / 15 mm, which was not extremely low, but peeling was possible (Comparative Example 2).

When the plastic layer was a single PCL, the surface was softened in the heat resistance evaluation, and adhesion to the boiled beans as contents was observed. In addition, the container was deformed due to the contraction of PCL due to heat (Comparative Example 3).

In the case of the PCL having a weight ratio of 25%, the water resistance was evaluated to be substantially good visually, but there were fine cracks and pinholes in the turpentine oil check, and the turpentine oil penetrated into the paper. In addition, the laminate strength was 300 gf / 15 mm, but peeled off.

The weight ratio of PCL is 50% or more, and the surface layer which is in direct contact with the food as the content is P (3HB-
3HV) alone had good heat resistance and no visual change was observed. In addition, there was no peeling between the paper and the layer of the adhesive surface, and all peeled off between the fibers of the paper. In addition, visual inspection of water resistance, water leakage and cracks,
It was not seen as a pinhole. In addition, the degradability was that the shape of the paper and the plastic layer did not remain after immersion in the activated sludge tank for one month (Examples 1, 2, and 3).

<Embodiment 4> Configuration of Embodiment 1 (paperboard / PC
L / P (3HB-3HV)) laminated paper of 1 liter in inner volume as shown in Fig. 4 was filled with hot water at 60 ° C.
Neither deformation of the container, change in surface condition, nor leakage of drinking water was observed.

[0039]

As described above, the conventional plastic paper container uses a non-degradable plastic such as polyolefin as the plastic laminate, so that it is buried after use or scattered as garbage in the natural environment. , Had retained its form almost permanently, but by using biodegradable plastics, paper is biodegradable, so the entire paper container becomes biodegradable and decomposes in landfills and natural environments . In addition, by forming a layer structure of the biodegradable plastic as in the present invention, it can be used for food applications, and satisfies all the functions of preventing leakage of contents, maintaining hygiene of contents, and sealing by heat sealing. A plastic paper container can be obtained.

[0040]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a laminate showing a configuration of a plastic paper container of the present invention.

FIG. 2 is a developed view showing one embodiment of the plastic paper container of the present invention.

FIG. 3 is a perspective view of a plastic paper container according to an embodiment of the present invention after a box is made.

FIG. 4 is a perspective view of a plastic paper container according to an embodiment of the present invention after a box is made.

[Explanation of symbols]

 1: Surface layer 2: Adhesive layer 3: Paper

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Motoyoshi Yoshikawa 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. Examiner Yuko Nitani (56) References JP-A-4-298345 (JP, A) JP-A-5-43793 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B65D 5/56

Claims (2)

(57) [Claims] 1. A plastic paper container comprising a laminate of paper and plastic, wherein a surface layer comprising 3-hydroxybutyric acid / 3-hydroxyvaleric acid copolymer is provided on the paper via an adhesive layer comprising poly-ε-caprolactone. A plastic paper container comprising a laminated body. 2. The adhesive layer comprising poly-ε-caprolactone, comprising a mixture of polyε-caprolactone and another biodegradable plastic, wherein the content of polyε-caprolactone is 50% by weight or more. The plastic paper container according to claim 1, wherein: