JP3881211B2 - Food containers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a food container for storing food.
[0002]
[Prior art]
Japanese Laid-Open Patent Publication No. 6-239334 discloses a paper container in which a natural fiber or recycled fiber is impregnated with 5 to 20% by weight of a polyolefin-based thermoplastic synthetic resin to form a sheet, and the sheet is formed into a container by pressing. is doing. Despite having paper as the main component, this container can be molded into a complex shape using press molding technology and has the strength, water resistance and oil resistance required for food containers. It has the effect of being able to.
[0003]
[Problems to be solved by the invention]
The container disclosed in the publication is formed by pressing a sheet in which natural fiber or recycled fiber is impregnated with 5 to 20% by weight of a polyolefin-based thermoplastic synthetic resin, and the container is made by a molding method other than pressing. And other molding techniques such as injection molding, blow molding, inflation molding, vacuum molding, and melt compression molding cannot be used. Moreover, in this container, since natural fiber and a reproduction | regeneration fiber are exposed to the inner surface, when food is stored in a container, those fibers may mix in food.
[0004]
In natural fibers and regenerated fibers, if these fibers are bleached by chlorination and then are not dechlorinated, trace amounts of chlorine may remain on the fibers. Moreover, in order to reduce the yellowing of these fibers, a fluorescent brightening agent may be added to these fibers. In the container disclosed in the above publication, if natural fiber or recycled fiber containing chlorine is used, or if natural fiber or recycled fiber to which a fluorescent whitening agent is added is used, chlorine or fluorescent whitening agent remains in the container. Resulting in. Chlorine and fluorescent brightening agents adversely affect the human body when they are ingested in large amounts, and therefore it is not preferable that the fiber containing them is mixed into food through the container.
[0005]
The subject of this invention is providing the container for foodstuffs which can be made by press molding and other shaping | molding methods, and an unnecessary substance does not mix in foodstuffs.
[0006]
[Means for Solving the Problems]
The premise of the present invention for solving the above-mentioned problem is a food container in which a food container is defined from a bottom wall and a peripheral wall extending upward from the periphery of the bottom wall.
[0007]
Feature of the present invention, the food container has a container body formed from a molding composition of a mixture of paper powder over having an average particle size of the thermoplastic synthetic resin and 30~80μm of polyolefin in said premise, coating at least the inner surface of the inner and outer surfaces of the container body, is composed of a synthetic resin layer having a port Li olefin thermoplastic synthetic resin, the paper powder, chlorine and fluorescent brightening agent- It is made by pulverizing pulp containing no paper or chlorine and no optical brightener, and the paper powder is substantially uniformly dispersed in the thermoplastic synthetic resin .
[0008]
According to one preferred embodiment of the present invention, the weight ratio of the thermoplastic synthetic resin to the total weight of the container body is in the range of 25 to 80 wt%, the weight of the paper powder to the total weight of the container body The ratio is in the range of 20 to 75% by weight.
[0009]
[0010]
As another example of the embodiment of the present invention, the synthetic resin layer has a thickness dimension in the range of 1 to 250 μm.
[0011]
As another example of the embodiment of the present invention, the thermoplastic synthetic resin may be ethylene-propylene elastomer, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene / olefin crystal block copolymer, metallocene polyethylene (C4, C6, C8). In the molding composition, the weight ratio of the modifying substance to the total weight of the thermoplastic synthetic resin is in the range of 0.1 to 20% by weight. is there.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The details of the food container according to the present invention will be described with reference to the accompanying drawings.
[0013]
1 and 2 are a perspective view of the food container 1 and an end view taken along line AA of FIG. In FIG. 1, the horizontal direction is indicated by an arrow X, and the vertical direction is indicated by an arrow Y. In FIG. 2, the paper powder 7 that cannot be visually observed is indicated by dots.
[0014]
The food container 1 has a substantially rectangular parallelepiped shape that is long in the vertical direction, and is formed of a substantially rectangular bottom wall 2 and four substantially rectangular side walls 3 (peripheral walls) extending upward from the periphery of the bottom wall 2. In the food container 1, the flange 4 extends outward in the circumferential direction from the top edge 3 a of the side wall 3 so as to be parallel to the bottom wall 2. The food container 1, food storage unit 5, which is more surrounded by the bottom wall 2 and side walls 3 are defined. However, the food container 1 is not limited to the illustrated one, and the shape thereof is not particularly limited as long as the storage portion 5 capable of storing food is defined from the bottom wall 2 and the peripheral wall 4.
[0015]
Food container 1 comprises a container body formed from a thermoplastic synthetic resin 6 and paper powder 7 and the molding composition 8 prepared by mixing the polyolefin, the formed type composition 8, a thermoplastic synthetic resin 6 The paper powder 7 is dispersed almost uniformly. Container body, its inner surface 1a is coated with a synthetic resin layer 9 made of a thermoplastic synthetic resin of the polyolefin, and thereby form a food container 1. Here, the inner surface 1a of the container body refers to the surface on the food storage unit 5 side.
[0016]
As the polyolefin-based thermoplastic synthetic resin 6 , any one of polypropylene and polyethylene, or a mixture of them in a given ratio can be used. As the polypropylene, at least one of block polymerized polypropylene, random polymerized polypropylene, homopolymerized polypropylene, metallocene catalyst polypropylene, and modified polypropylene can be used. As the polyethylene, at least one of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, metallocene catalyzed polyethylene, and modified polyethylene can be used.
[0017]
The paper powder 7 has a particle size in the range of 1 to 200 μm and an average particle size in the range of 30 to 80 μm. The paper powder 7 does not contain chlorine and a fluorescent brightening agent. The paper powder 7 may be made by finely pulverizing the paper itself, or may be made by finely pulverizing broken paper or damaged paper generated when the paper is manufactured. As the paper for making the paper powder 7, it is preferable to use at least one of sanitary paper, food container base paper, and electrical insulating paper.
[0018]
As the sanitary paper, at least one of tissue paper, dust paper, toilet paper, and sanitary paper can be used. The food container base paper is a base paper used for paper cups, paper plates, and small liquid containers. The electrical insulating paper includes at least one of insulating paper for communication cable, insulating paper for power cable, coil insulating paper, electrolytic capacitor paper, capacitor thin paper, high voltage capacitor paper, insulating thin paper, press board, fish paper, press pan. One can be used. When the pulp that is the raw material of these papers is bleached by chlorination, it is necessary that the bleached pulp has been dechlorinated. In addition, these papers need to be made from pulp to which no optical brightener has been added.
[0019]
The paper powder 7 can also be made by finely pulverizing the pulp itself. The paper powder 7 made from pulp preferably has a lignin component of 1% or less. As the pulp, at least one of mechanical pulp, chemical mechanical pulp, semi-chemical pulp, and chemical pulp can be used. As the pulp, wood pulp is preferably used, but at least one of rag pulp, stalk and straw pulp, and bast pulp can be mixed with wood pulp. If the pulp is bleached by chlorination, use a pulp that has been dechlorinated. The pulp is not added with an optical brightener.
[0020]
An injection molding technique can be used to manufacture the container body . Into a hopper of an injection molding machine (not shown), a thermoplastic synthetic resin 6 and a paper powder 7 that are preliminarily formed into a pellet are put. Inside the injection molding machine, the thermoplastic synthetic resin 6 and the paper powder 7 are heated, and the thermoplastic synthetic resin 6 and the paper powder 7 are kneaded through a screw of the injection molding machine to melt at a high temperature. Composition 8 is obtained. In the molten molding composition 8, the paper powder 7 is dispersed substantially uniformly in the thermoplastic synthetic resin 6. The molding composition 8 is poured into a mold from a nozzle formed at the tip of the injection molding machine, and is cooled and solidified in the mold to become a container body . The container body can be manufactured by using blow molding or inflation molding technology in addition to the injection molding technology.
[0021]
The container body can also be manufactured by subjecting the molding composition 8 to secondary processing. For the secondary processing, it is possible to use a molding technique such as vacuum molding, melt compression molding, or press molding. The molding composition 8 for secondary processing can be produced using an extruder (not shown). A thermoplastic synthetic resin 6 and a paper powder 7 that are preliminarily formed into a pellet are put into a hopper of the extruder. Inside the extruder, the thermoplastic synthetic resin 6 and the paper powder 7 are heated, and the thermoplastic synthetic resin 6 and the paper powder 7 are kneaded through the screw of the extruder to melt at a high temperature. It becomes thing 8. The molten molding composition 8 is extruded from a die attached to the tip of the extruder, and is cooled and solidified into a given shape. The molding composition 8 can be formed into a pellet, plate or sheet depending on the lip shape of the die.
[0022]
In the food container 1, it is possible to form a synthetic resin layer 9 by applying a molten polyolefin-based thermoplastic synthetic resin to the container body. Also, the food container 1, it is possible to form a synthetic resin layer 9 by immersing the container body molten polyolefin-based thermoplastic synthetic resin. In the food container 1, the thickness dimension L1 of the synthetic resin layer 9 is in the range of 1 to 250 μm, preferably the thickness dimension L1 is in the range of 10 to 100 μm.
[0023]
If the thickness L1 of the synthetic resin layer 9 is less than 1 μm , the paper powder 7 cannot be covered with the synthetic resin layer 9 and the paper powder 7 is exposed from the inner surface 1a of the container 1 so that food is stored in the food container 1. When doing so, the paper powder 7 may be mixed into the food.
[0024]
In the container body formed by the molding composition 8, the weight ratio of the polyolefin-based thermoplastic synthetic resin 6 to the total weight is in the range of 25 to 80% by weight, and the weight ratio of the paper powder 7 to the total weight is It is in the range of 20 to 75% by weight. The molding composition 8 has a melt flow index in the range of 1 to 10 g / 10 min.
[0025]
In the case where the thermoplastic synthetic resin 6 of polyolefin exceeds 25% by weight less than and paper powder 7 75% by weight, the original, the presence of paper powder 7 no indicate Succoth fluidity even when heated is a factor since thus significantly reduce the fluidity of the molding composition 8 Te, for example, when producing the container body by injection molding, does not flow smoothly in the molding composition 8 is the mold from the nozzle of the injection molding machine In some cases, the production of the container body may be hindered. In addition, the amount of the paper powder 7 with respect to the molding composition 8 is increased more than necessary, and the strength of the container body is significantly reduced, which is easily broken. In the case where the paper powder 7 is less than 20% by weight and the thermoplastic synthetic resin 6 exceeds 80% by weight, the amount of the thermoplastic synthetic resin 6 having higher combustion calories than the paper powder 7 is increased with respect to the molding composition 8, Burning calories during incineration of the container body cannot be reduced. In addition, the container body cannot be completely burned unless the incineration temperature is high.
[0026]
When the average particle size of the paper powder 7 is less than 30 μm, a plurality of steps are required to process the paper and pulp into an average particle size of less than 30 μm, which increases the production cost of the paper powder 7 and results. The production cost of the container 1 will increase. When the average particle diameter of the paper powder 7 exceeds 80 μm, the paper powder 7 may cause poor dispersion in the thermoplastic synthetic resin 6 , and a lump of the paper powder 7 may be formed in the molding composition 8. Yes, the strength of the container body at the site where the lump of paper powder 7 exists is significantly reduced.
[0027]
In the food container 1, the inner surface 1 a of the container body is covered with the synthetic resin layer 9, and the synthetic resin layer 9 prevents the contact between the paper powder 7 exposed from the inner surface 1 a of the container body and the food. Even if food is stored in the container, the paper powder 7 is not mixed into the food from the container body . In food container 1, since no food is in contact with the inner surface 1a of the container body, never food moisture and oil to seep therein from the inner surface 1a of the container body, the strength of the container body is reduced There is no end. Moreover, in the food container 1, the inner surface 1a of the container main body is not colored by the colorant added to the food. This food container 1 can be used repeatedly as well as disposable.
[0028]
Molding composition 8 than paper powder 7 to form it does not contain chlorine and fluorescent whitening agent, the container body is chlorine or fluorescent whitening made from this formed mold composition 8 It does not contain the agent. Further, the container body, because the molding composition 8 forming the same comprises paper powder 7, compared with the case where the container body is formed from only thermoplastic synthetic resin, the combustion during incineration of the container body Calories can be reduced. Since the molding composition 8 has a melt flow index in the above range, the molding composition 8 exhibits good fluidity and does not hinder the molding process of making a container body from the molding composition 8.
[0029]
In the container body, the polyolefin-based thermoplastic synthetic resin 6 forming the molding composition 8 may contain a modifying substance. In the molding composition 8, it is preferable that the weight ratio of the modifying substance to the total weight of the thermoplastic synthetic resin 6 is in the range of 0.1 to 20% by weight.
[0030]
As the modifying material, at least one of ethylene-propylene elastomer, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene / olefin crystal block copolymer, metallocene polyethylene (C4, C6, C8) can be used. .
[0031]
Hydrogenated styrene-butadiene rubber and styrene-ethylene butylene / olefin crystal block copolymer are highly random copolymers formed from ethylene and butene-1, and do not have a double bond in the polymer molecule. In addition, it is a polyolefin-based thermoplastic synthetic resin having low crystallinity and flexibility and high transparency.
[0032]
Reforming material, those having a thermoplastic synthetic resin 6 and mutual affinity, to form a thermoplastic synthetic resin 6 with the mixture, it is possible to improve the fluidity of the thermoplastic synthetic resin 6. In addition, the modifying substance functions as a binder that bonds the thermoplastic synthetic resin 6 and the paper powder 7 together. These modifiers have a melt flow index in the range of 25-100 g / 10 min.
[0033]
When the modifying substance is less than 0.1% by weight and the melt flow index of the modifying substance is less than 25 g / 10 minutes, the modifying substance does not function sufficiently and the fluidity of the molding composition 8 is improved. I can't.
[0034]
In the molding composition 8 forming the container body , at least one of starch and powdered inorganic substance may be mixed therein. In the molding composition 8, the weight ratio of starch to the total weight of the paper powder 7 is preferably in the range of 10 to 25% by weight, and the average particle size of starch is preferably in the range of 5 to 150 μm. In the molding composition 8 containing starch, the burning calories of starch are lower than that of the paper powder 7, so that the burning calories of the container body can be further reduced.
[0035]
In the molding composition 8, the weight ratio of the inorganic substance to the total weight of the paper powder 7 is preferably in the range of 1 to 25% by weight. In the molding composition 8 in which an inorganic substance is mixed, since the inorganic substance is nonflammable, the combustion calories of the container body can be further reduced. As the inorganic substance, at least one of titanium oxide, talc, calcium carbonate, calcium sulfate, barium sulfate, and kaolin can be used.
[0036]
The melt flow index between the molding composition 8 and the modifying material is such that the temperature of the molding composition 8 and the modifying material is 160 to 180 ° C., the extrusion pressure is 3.0 to 5.0 / kg, and the extrusion time is It is a value measured by extruding from an orifice having a specified diameter and length for 10 minutes.
[0037]
In the illustrated food container 1, the thermoplastic synthetic resin layer 9 covers the inner surface 1 a of the container main body , but the inner surface 1 a and the outer surface 1 b of the container main body may be covered by the thermoplastic synthetic resin layer 9. .
[0038]
【The invention's effect】
According to a food container according to the present invention, at least the inner surface of the inner and outer surfaces of the container body is covered with a synthetic resin layer comprising a polyolefin-based synthetic resin, paper powder synthetic resin layer is exposed from the inner surface of the container body and so prevents contact with food, even food was stored in food containers, never paper powder from the container body will be mixed into the food, to prevent unwanted materials are mixed into the food Can do. In this food container, since the container body is formed from a molding composition in which a polyolefin-based thermoplastic synthetic resin and paper powder are mixed, compared to the case where it is formed only from a thermoplastic synthetic resin. The combustion calories at the time of incineration of the container body can be reduced.
[0039]
In this food container, the food does not come into contact with the inner surface of the container body , so that the moisture and oil content of the food does not permeate into the container body from the inner surface and the strength of the container body is reduced. There is no. This food container can be used repeatedly as well as disposable. In this food container , the container body can be made not only by press molding, but also by using molding techniques such as injection molding, blow molding, inflation molding, vacuum molding, and melt compression molding.
[0040]
In food containers, including paper bodies where the paper powder does not contain chlorine and optical brightener, or a container body made by pulverizing pulp that does not contain chlorine and optical brightener, the container body is chlorine In addition, it does not contain a fluorescent brightening agent, improves safety, and is suitable for foods.
[0041]
In the molding composition containing the modifying substance in the polyolefin-based synthetic resin , the fluidity can be improved. Therefore, the container body can be easily made from the molding composition by using the molding processing technique. It will not interfere with the manufacture of the container body .
[Brief description of the drawings]
FIG. 1 is a perspective view of a food container.
FIG. 2 is an end view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Food container 1a Inner surface 1b Outer surface 2 Bottom wall 3 Side wall (peripheral wall)
5 Food Storage 6 Polyolefin Thermoplastic Synthetic Resin 7 Paper Powder 8 Molding Composition 9 Synthetic Resin Layer L1 Thickness

Claims (4)

In the food container in which the food storage portion is defined from the bottom wall and the peripheral wall extending upward from the periphery of the bottom wall,
The food container includes a container body formed from a molding composition of a mixture of paper powder over having an average particle size of the thermoplastic synthetic resin and 30~80μm of polyolefin, the inner and outer surfaces of the container body coating at least the inner surface of the inner, it is composed of a synthetic resin layer having a port Li olefin thermoplastic synthetic resin,
The paper powder is made by pulverizing paper that does not contain chlorine and optical brightener or pulp that does not contain chlorine and optical brightener, and the paper powder is abbreviated to the thermoplastic synthetic resin. A food container characterized by being uniformly dispersed . The weight ratio of the thermoplastic synthetic resin to the total weight of the container body is in the range of 25 to 80 wt%, the weight ratio of the paper powder to the total weight of the container body, in the range of 20 to 75 wt% food containers of a claim 1, wherein. The food container according to claim 1, wherein the synthetic resin layer has a thickness dimension in the range of 1 to 250 μm . The thermoplastic synthetic resin is a modified material comprising at least one of ethylene-propylene elastomer, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene / olefin crystal block copolymer, and metallocene polyethylene (C4, C6, C8). 4. The molding composition according to claim 1, wherein a weight ratio of the modifying substance to a total weight of the thermoplastic synthetic resin is in a range of 0.1 to 20 wt% in the molding composition. Container for food.

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