JPH0762163A - Polyolefin resin composition for food container - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. giving a food container from which the contents thermally solidified therein can be easily and smoothly taken out by compounding a polyolefin resin with an ingredient such as a polyhydric alcohol (deriv.). CONSTITUTION:The title compsn. is obtd. by compounding a polyolefin resin such as polyethylene or polypropylene with an ingredient selected from a polyhydric alcohol, its deriv., and a polyoxyethylene deriv. Examples of the polyhydric alcohol and its deriv. are ethylene glycol, propylene glycol, and stearic acid glyceride; an example of the polyoxyethylene deriv. is a polyoxyethylenealkylamine. When a container made by molding the compsn. is filled with the material of e.g. a pudding, the contents can easily be taken out without adhering to the inside wall of the container or without being partially chipped off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin-based resin composition for food containers, and particularly to the one obtained by heating and solidifying the contents of raw materials such as pudding, egg tofu and water yokan in a container after heating and solidifying. The present invention relates to a technique that makes it easy to take out the product and prevents the contents from being partially chipped or attached to the inner surface of the container.

[0002]

2. Description of the Related Art A polyolefin resin represented by polypropylene resin, which is characterized by its heat resistance, safety and hygiene, transparency, etc., is used as a molding material for containers such as pudding, egg tofu and water yokan. However, the contents such as pudding, egg tofu, and water yokan contain water, and since they are heated and solidified by retort processing after filling the raw material contents, they easily adhere to the inner surface of the container, and therefore the contents are extracted. , When the product is taken out to the outside, part of the contents may be chipped or it may be difficult to take out because it adheres to the inner surface of the container. For this reason, a protrusion is provided on the bottom surface of the container, which is bent at the time of use, and air is introduced into the container to improve the releasability. However, in this case, there is a problem that the product shape becomes complicated due to the presence of the protrusions, the mold must be devised, and the molding process cannot be performed smoothly. Further, even if such a measure is taken, there are still problems such that the content does not come off easily when it is extracted, or a part of the content adheres to the container so that the content cannot be removed properly.

As another method, corona treatment of a molded article,
Electron beam treatment, other radiation treatment, chemical treatment such as acid,
A method of applying an antistatic agent or the like can be considered, but there is a problem that the processing is complicated.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of the prior art, and in particular, after filling the contents of raw materials such as pudding, egg tofu and water yokan into a container, it is heated and solidified. It is an object of the present invention to provide a technique that makes it easy to take things out and to prevent the contents from being partially chipped or attached to the inner surface of the container. Another object of the present invention is to maintain the characteristics as a good food container material such as heat resistance, safety and hygiene and transparency, and at the same time, for the food container having a good releasability of the contents as described above. It is an object of the present invention to provide a technique capable of obtaining a polyolefin material. Other objects and novel features of the present invention will be apparent from the entire description of the present specification.

[0005]

The present invention for achieving the above object is characterized in that a compounding agent selected from polyhydric alcohols or their derivatives and polyoxyethylene derivatives is added to a polyolefin resin. The present invention relates to a polyolefin resin composition for food containers.
According to the present invention, since the raw material content containing water is heated and solidified in the retort process after filling, it easily adheres to the inner surface of the container, and therefore, when the content is extracted and taken out, the content is For containers such as pudding, egg tofu, and water cans that are difficult to remove because they are partially chipped or adhere to the inner surface of the container, they are easy to remove, so it is easy to remove the contents when extracting them and removing them to the outside. be able to.
In addition, since it is an improvement in terms of the molding material, it is possible to avoid the problems of the related art.

Examples of the polyolefin resin used in the present invention include ethylene, α-olefins such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and other olefin homopolymers, and olefins. Alternatively, a copolymer with two or more kinds of other olefins and the like are exemplified. These polyolefin resins can be used not only individually, but also as a mixture thereof.
Further, in the case of a mixture, it is possible to use one produced by stepwise (co) polymerizing the same or different olefin monomers.

The compounding agent used in the present invention is selected from polyhydric alcohols or their derivatives and polyoxyethylene derivatives. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, pentanediol, glycerin, tetrit, pentaerythritol, sorbitol, polyethylene glycol, and the like, and the derivatives thereof include the above polyhydric alcohol and 6 to 22 carbon atoms. Fatty acids such as stearic acid,
Lauric acid, oleic acid, caproic acid, palmitic acid,
Esters of linoleic acid and linolenic acid, 1,3,2,4
Sodium (para-methylbenzylidene) sorbitol and the like. Specific examples of the ester of the above polyhydric alcohol and the above fatty acid include stearic acid monoglyceride, oleic acid monoglyceride, lauric acid monoglyceride, sorbitan monolaurate, sorbitan monostearate, and propylene glycol monostearate. Examples of the polyoxyethylene derivative include polyoxyethylene alkylamine represented by the general formula RN [(CH ₂ CH ₂ O) nH] ₂ , and general formula RCON [(CH ₂
CH ₂ O) nH] [(CH ₂ CH ₂ O) mH] represented by the general formula RO (C
Examples thereof include polyoxyalkyl ethers represented by H ₂ CH ₂ O) nH. In each of the above formulas, R has 6 carbon atoms
To 22 alkyl groups or alkenyl groups, and n and m are integers of 1 or more and 100 or less. Specific examples of the polyoxyethylene derivative include, for example, stearyl-diethanolamine, lauriludiethanolamine,
Examples thereof include oleyldiethanolamine, stearyl-diethanolamide, lauriludiethanolamide, oleyldiethanolamide, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether and the like. Further, these derivatives can be used as a mixture with a higher alcohol such as stearyl alcohol.

In the present invention, one or more of the above compounding agents may be added to the polyolefin resin, melt-kneaded, and molded into a food container. The amount of the compounding agent added may be such that the contact angle of the inner surface of the molded food container with water is 60 degrees or less, preferably 40 degrees or less, and the amount is usually 0.05 to 2 0.0%, preferably 0.1 to 0.
5%. Therefore, the food container is molded such that the contact angle of its inner surface to water is 60 degrees or less, preferably 40 degrees or less, and the obtained food container contains raw material contents such as pudding, egg tofu, and water yokan. And then,
The process moves to the retort treatment step and is heated and solidified. The content contains water and is closely packed to the inner surface of the food container.

If necessary, a neutralizing agent, an antioxidant, an inorganic filler and the like can be added to the above composition of the present invention. Preferred examples of the neutralizing agent include magnesium stearate, calcium stearate, barium stearate, zinc stearate, aluminum stearate, calcium citrate, calcium lactate, 1
Examples thereof include calcium 2-hydroxystearate, calcium stearyl lactate, and calcium lauryl lactate. An example of the antioxidant is pentaerythritol-tetrakis [3- (3, which is a phenolic antioxidant.
5-di-t-butyl-4-hydroxyphenyl) propionate]; phosphorus-based antioxidant tris (2,4-
Di-t-butylphenyl) phosphite and the like can be mentioned. Examples of inorganic fillers include talc, calcium carbonate, gypsum, carbon black, clay, kaolin,
Examples thereof include silica and diatomaceous earth. Further, if necessary, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a coloring agent, a natural rubber, a synthetic rubber, another resin or the like can be added appropriately.

[0010]

EXAMPLES Next, the present invention will be explained based on the following examples and comparative examples. The molding materials used in the following examples are as follows. Polypropylene resin: ethylene-propylene random copolymer (ethylene content 3%, MFR = 15 g / 10
Min) GMS: glycerin monostearate (Riken Vitamin Co., trade name Liquemal S100) Oxyethylenealkylamine: Stearyl-L-Glue Ethanolamine and stearyl alcohol mixture (Kao, trade name Electrostripper TSK) Gel All MD: 1,3 , 2,4-Di (para-methylbenzylidene) sorbitol (manufactured by Shin Nippon Rika Co., Ltd.) IR1010: tetrakis [methylene-3- (3 ',
5'-t-butyl-4'-hydroxyphenyl) propionate] methane (antioxidant, Irganox
1010, product of Ciba Geigy, trade name MARK 2112: tris (2,4-di-t-butylphenyl) phosphite (antioxidant, product of Asahi Denka Co., Ltd., trade name) CA-ST: calcium stearate (neutralizing agent) The evaluation results of the releasability of the contents are shown in the following three stages. ◯: Defect failure of 10 out of 10 Δ: Defect defect of up to 2 in 2 or less ×: Failure of releasability in 10 of 3 or more

Examples 1-3. According to the formulation shown in Table 1, polypropylene resin was blended with various additives and dry-blended using a super mixer, and then a single-screw extruder (50
mmφ, L / D = 28), and the obtained pellets are injection-molded to 70 mm (length) × 70 mm (width) × 3.
A 0 mm (height) container was molded. The contact angle of the inner surface of this container with water was measured. Next, the raw material of egg tofu was placed in this container, sealed with a polypropylene film, and then heat-treated at about 90 ° C. for 30 minutes. The results are shown in Table 1.

Comparative Example 1. In the same manner as in Example 1 except that the compounding agent was not added, a container made of polypropylene resin was molded according to the composition shown in Table 1, and the contact angle of the inner surface of the container with water was measured. Next, the raw material of egg tofu was placed in this container, sealed with a polypropylene film, and then heat-treated at about 90 ° C. for 30 minutes. The results are shown in Table 1.

[0013]

[Table 1]

Although the invention made by the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

[0015]

As described above, according to the present invention, since water is contained and the raw material contents are filled and heated and solidified by retort treatment, they easily adhere to the inner surface of the container. When removing to a part, the contents are partially chipped, and it is difficult to remove the contents because it adheres to the inner surface of the container and it is easy to remove it in containers such as pudding, egg tofu, and water yokan It can be easily taken out when taking it out. Also, because it is an improvement from the molding material side, by providing a protrusion on the bottom surface of the conventional container, when using,
The product shape becomes complicated as seen in the method of bending and putting air in to improve the mold releasability, and the mold needs to be devised, or the molding process does not go smoothly. The problem can be avoided, and the process is complicated and manufactured as seen in methods such as corona treatment, electron beam treatment, other radiation treatment, chemical treatment such as acid, coating of antistatic agent, etc. on molded products. Problems such as cost increase can be avoided.

Claims (1)

[Claims] 1. A polyolefin-based resin composition for food containers, which is obtained by adding a compounding agent selected from polyhydric alcohols or their derivatives and polyoxyethylene derivatives to a polyolefin resin.