JP2760412B2 - Food trays and cases - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to food trays and cases used for transporting meat, fish, vegetables, eggs, and the like, and displaying in a showcase.

[Conventional technology and its problems]

2. Description of the Related Art In recent years, when fresh foods such as meat, fish, vegetables, eggs, and the like are transported or displayed in a showcase at a food store such as a supermarket, a department store, or a retail store, a small portion of the food is received in a tray using styrene foam resin. Food trays and cases are used. The amount of food trays used is enormous, and most of them are discarded by general households, food processors and the like to become garbage.

These food trays and cases are foamed resin products, so they have a large volume in spite of their light weight and do not disassemble when discarded in landfills, which poses a serious problem.

In the metropolitan areas of Tokyo and Osaka, it is predicted that the places where urban garbage will be dumped will disappear in the last few years, and even if incinerated, the generation of harmful gas becomes a problem, causing environmental pollution.

There is a great social need to make food trays and cases into products that can be quickly degraded by microorganisms in the soil.

[Means for solving the problem]

The present invention is light, as a food tray or case in view of the above drawbacks, has strength, has shape stability and water resistance,
An object of the present invention is to provide a tray that is safe, inexpensive, and has biodegradability.

That is, the present invention is to form a fiber formed of a cellulose structure such as cotton or rayon into a web, and to form a nonwoven fabric which is decomposed by microorganisms in soil with an interfiber binder mainly composed of chitosan. Then, the above problem is solved by heating and compression molding.

The fiber used in the present invention achieves its purpose as long as it is a natural fiber such as cotton or hemp having a cellulose structure, a regenerated fiber such as viscose rayon or copper ammonia rayon, or a semi-synthetic fiber such as acetate. It is also possible to use these mixed fibers.

The formation of the nonwoven fabric using the above fibers may be any of a parallel web, a cross web or a random web constituted by using a known web forming machine, and these webs are directly treated with an interfiber binder mainly composed of chitosan salt. Alternatively, these webs may be subjected to needle punching or water needle punching to physically entangle the fibers in advance.

Next, the entangled web is prepared by dissolving chitosan in a 0.5 to 1.0% aqueous solution of an organic acid such as acetic acid or citric acid to a concentration of 0.5 to 1.0%, or mixing fine cellulose with the chitosan salt aqueous solution. The aqueous solution of chitosan salt is used as an inter-fiber binding agent by dipping or spraying.
Chitosan is added in an amount of 1 to 5 parts by weight (solid content) with respect to 0 parts by weight (solid content), and the water repellent is adjusted to an adhesion amount of 1 to 10 parts by weight (solid content) and then dried to form a nonwoven fabric. If the water repellent is less than 1 part by weight, it is not preferable because it absorbs water and easily loses its shape, and if it exceeds 10 parts by weight, the biodegradation time will be unnecessarily prolonged.

Also, the basis weight of the nonwoven fabric is required to be 200 g / m ² or more,
If it is less than m ^2, sufficient strength required for shape retention cannot be obtained.

As a method for molding the water-repellent-treated biodegradable nonwoven fabric thus formed, heat compression molding by a press machine is effective, and the fiber density is increased to 0.2 g / cm ³ or more by compression molding. If it is less than 0.2 g / cm ³ , the effect of the water repellent will not be sufficiently exhibited, and the cellulose fiber will easily lose its shape due to its absorbency, and the strength will be insufficient.

It is known that a chitosan salt aqueous solution solidifies when dried, but since the solidified product is a chitosan salt, it swells in water unless further fixed with alkali, and further dissolves. However, if heated and dried together with the cellulose, a reaction with the cellulose occurs, and the cellulose does not dissolve in water.

Furthermore, by mixing fine cellulose fibers having a diameter of 1 μm or less formed by beating pulp or the like into a chitosan salt aqueous solution, the water resistance can be improved.

In addition, food trays need to be water-repellent so that they do not absorb protein juice such as fish juice and meat juice. As the water-repellent agent, carbon atoms that are easily biodegraded by microorganisms in the soil are required. A water-repellent agent of an aliphatic compound and an aliphatic compound derivative having a structure connected in a chain in a line is preferable.

Specifically, N-octadecyl ethylene urea, stearic acid chloride, alkyl ketene dimer, quaternary ammonium salt of fatty acid, stearic acid amide, 2-ethylhexyl zirconate and the like are used.

(Operation)

The food tray according to the present invention, having the structure shown in FIGS. 1 and 2, has a sufficient practical strength as a food container, has excellent water repellency, is light and easy to handle, and is made of plastic. It does not break even when folded like a container, and after use, it is eliminated in the soil in a short time in landfill as industrial waste, and it is released from environmental pollution.

 Hereinafter, an embodiment of the present invention will be described.

〔Example〕

As shown in FIG. 1 , (1) is a sectional view of the structure of the biodegradable nonwoven fabric used in the present invention. The nonwoven fabric is formed by a web forming machine using rayon fibers (2) 2d × 38 mm as cellulosic fibers. For example, a cross web (3) having a basis weight of 350 g / m ² is used.

The web is subjected to a needle punching process of 100 P / cm ^{2 by} a needle punching machine, whereby the fibers are entangled with each other to form a temporarily fixed needle punch web. (4) shows a fiber entangled state after needle punching.

The thus-prepared temporary-needle punch web is prepared by preparing an aqueous solution of chitosan salt having a concentration of 1% with a chitosan: lactic acid ratio of 1: 1 (weight ratio), and fine cellulose and a water repellent having the following composition. After being immersed in the contained solution, the mixture is dried at 100 ° C. for 5 minutes in a hot air drier to form a decomposable nonwoven fabric in which fibers are fixed with chitosan salt (5).

(Combination) (parts by weight) 1% chitosan salt aqueous solution 100 parts (Kyowa Oil & Fat Flownac C) fine cellulose fiber 2.3 parts (Daicel MFC-100) Water repellent (octadesil ethylene urea) 1.25 parts Hodogaya Chemical Octex EM 40% This nonwoven fabric had a solid content of chitosan of 7.0 g / m ² , a water repellent of 3.5 g / m ^{2 of} solid content adhered to the fiber, and had a basis weight of 361 g / m ² and a thickness of 1.2 mm. . This nonwoven fabric was heat-compressed using a heat-compression molding machine.

The above nonwoven fabric is sandwiched between the concave mold and the convex mold, and the pressure is about 5
Tons are added, the mold is heated to 100 ° C and the compression time is 30 seconds, length 20cm x width 11cm x depth 10mm, weight 7.5g, nonwoven fabric density 0.
A tray-like food tray of 27 g / cm ³ was obtained. FIG. 2 is a perspective view of the food tray (6) formed in this manner, and a dense and excellent container is formed.

When this biodegradable food tray was buried in the soil, it completely decomposed and disappeared in about 2.2 months. The shape and size of the tray are not limited to those in the above-described embodiment, and a desired shape and size can be obtained by changing a molding die.

FIG. 3 shows another embodiment of the present invention, in which a water repellent and an aqueous solution of chitosan salt containing fine cellulose fibers are used as an interfiber binder in the same manner as in the above-mentioned embodiment. Glued, chitosan 15g / m ² ,
About thick water repellent adhering to 8 g / m ² fibers 2.0mm basis weight 523 g / m ²
Using a decomposable nonwoven fabric, a desired number of small containers (7) are adjacent to each other in an uneven state, and a pair of upper and lower uneven containers formed continuously are pressured to 10 tons by a mold using a hot compression molding machine. 100
Thermoforming was performed at 30 ° C for 30 seconds to form an egg case (8) in which several small containers were connected. The present invention is not limited to the above-described embodiment, and various shapes of food cases can be formed by molding by changing the mold.

〔The invention's effect〕

Since the present invention uses chitosan as an interfiber binder as described above, the decomposition of cellulose fibers by microorganisms in the soil is promoted, the cellulose fibers are completely decomposed in a short period of time, and the activity of microorganisms in the soil may be inhibited. Absent. Further, this tray has sufficient strength even when food is placed thereon, and prevents water absorption of meat juice, fish juice and the like from being absorbed, and is excellent in water repellency.

This biodegradable tray is very useful in the distribution of fresh food such as meat, fish, vegetables, etc., and the garbage waste from general consumers and food processors is decomposed in landfills in a short time. It is an invention that has various effects such as becoming fertilizer, helping to reduce urban garbage, and being free from environmental pollution.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a biodegradable nonwoven fabric used in the present invention, FIG. 2 is a perspective view of a food tray showing one embodiment of the present invention, and FIG. It is a perspective view of a case. (1) ... biodegradable nonwoven fabric (2) ... rayon fiber (3) ... cross web (4) ... fiber entangled state (5) ... chitosan salt (6) ... food tray (7) ... … Small container (8) … Egg case

Continued on the front page (72) Inventor Takamasa Kubo 2-3-3 Hananomiyacho, Takamatsu-shi, Kagawa Prefecture Inside the Industrial Technology Research Institute, Shikoku Industrial Research Institute (72) Inventor Kazunori Yoshihara 2 Hananomiyacho, Takamatsu-shi, Kagawa Prefecture 3-3-3, Shikoku Industrial Technology Laboratory, National Institute of Industrial Science (72) Inventor Mutsumi Nakagawa 1-21-15, Mefu, Takarazuka-shi, Hyogo (72) Inventor Teruhiro Komatsu 2-4-2-50 Mukotoyo-cho, Amagasaki-shi, Hyogo ― 306 Examiner Yasushi Ohashi (58) Field surveyed (Int. Cl. ⁶ , DB name) B65D 1/34 B65D 1/00

Claims (3)

(57) [Claims] 1. A fibrous web composed of cellulosic natural fibers, cellulosic regenerated or semi-synthetic fibers or a mixture thereof, is bonded with an interfiber binder mainly composed of chitosan salt, and 100 parts by weight of the fibers. the water repellent in solids consists basis weight 200 g / m ² or more were attached to 10 parts by weight of the biodegradable nonwoven fabric, formed into an apparent density 0.2 g / cm ³ or more compression molded saucer shape against A food tray, comprising: 2. The food tray according to claim 1, wherein the water repellent is an aliphatic compound or an aliphatic compound derivative. 3. A food case, wherein a plurality of small containers obtained by compression-molding the biodegradable nonwoven fabric according to claim 1 comprise a pair of upper and lower containers which are continuously formed in an uneven state. .