JP2003237825A - Transparent resin composition for food container and packaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent resin composition for food containers and food packaging materials which can prevent any discoloration of foods, degradation of the quality thereof, etc., caused by ultraviolet rays without impairing the appearance by the sign of yellowing. <P>SOLUTION: The transparent resin composition for food containers and food packaging materials is constituted by containing ultraviolet ray absorbent and fluorescent brightening agent in the transparent resin. The ratio of the ultraviolet ray absorbent in the transparent resin composition is preferably 0.01 to 0.3 wt.%, and the ratio of the fluorescent brightening agent in the transparent resin composition is preferably 0.0001 to 0.05 wt.%. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a transparent resin composition (hereinafter referred to as “transparent resin composition for food container / packaging material”) used as a container for food or a base material for packaging material for packaging food. More specifically, it protects food from discoloration or deterioration of quality by blocking ultraviolet rays, and does not spoil the appearance due to yellowing.
The present invention relates to a transparent resin composition for packaging materials.

[0002]

2. Description of the Related Art Conventionally, a transparent resin composition comprising a transparent resin containing an ultraviolet absorber has been used as a transparent resin composition for food containers and packaging materials capable of preventing discoloration of foods due to ultraviolet rays or deterioration of quality. It is known to be used.
However, in this conventional transparent resin composition containing an ultraviolet absorber, a slight yellowish color is unavoidable, and therefore, for example, the color tone of the food of the contents is subtly changed in appearance, and there is a problem of impairing the appearance. is there.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, an object of the present invention is to prevent food from being discolored or deteriorated in quality by ultraviolet rays without being yellowed and impairing its appearance. It is to provide a transparent resin composition for a material.

[0004]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that a transparent resin composition for food containers and packaging materials, which can prevent discoloration and deterioration of quality of food due to ultraviolet rays. As a result, it has been found that if the transparent resin composition is constituted by using a fluorescent whitening agent together with an ultraviolet absorber, the yellowing of the transparent resin composition can be suppressed and the above object can be achieved. Further, it has been found that the fluorescent whitening agent is generally relatively unstable to light and easily deteriorates, but when used together with the ultraviolet absorber, the deterioration is suppressed. The present invention has been completed based on these findings.

That is, in order to achieve the above object, the present invention provides a transparent resin composition for a food container / packaging material, which comprises a transparent resin containing an ultraviolet absorber and a fluorescent whitening agent. To do.

In the transparent resin composition of the present invention, the yellowing is suppressed by the combined use of the fluorescent whitening agent of 340 to 400.
It absorbs the energy of UV rays of nm and it is 400-5
It is considered that the light is emitted as blue light in the visible region of 00 nm, which cancels the yellowing of the transparent resin composition and becomes colorless. In the field of transparent resin compositions for food containers and packaging materials, the combined use of an ultraviolet absorber and a fluorescent whitening agent, no examples of which have been found before the present invention, and the first achievement of the present invention. is there.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the transparent resin composition of the present invention, various conventionally known transparent resins can be appropriately selected and used as the base transparent resin, provided that they are harmless to the human body. . Examples thereof include polyethylene, polypropylene, polymethylpentene, polybutene-1, butadiene resin, polystyrene, AS resin,
Examples thereof include ABS resin, fluororesin, polymethacrylstyrene, nylon, polyethylene terephthalate, polycarbonate, polyvinyl alcohol, polybutylene terephthalate, polyarylate and polycyclohexylene dimethylene terephthalate.

As the ultraviolet absorber, various conventionally known ultraviolet absorbers can be appropriately selected and used, which are harmless to the human body. As an example,
Salicylic acid-based UV absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-
Benzophenone-based UV absorbers such as sulfobenzophenone and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane; 2- (2'-hydroxy-5 '
-Methylphenyl) benzotriazole, 2- (2'-
Hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-
Di-tert-butylphenyl) benzotriazole,
2- (2'-hydroxy-3'-tert-butyl-5
′ -Methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-ter
t-Butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-ter
t-amylphenyl) benzotriazole, 2- {2 '
-Hydroxy-3 '(3 ", 4", 5 ", 6"
-Tetrahydrophthalimidomethyl) -5'-methylphenyl} benzotriazole, 2,2-methylenebis {4- (1,1,3,3-tetramethylbutyl) -6-
(2'-benzotriazol-2-yl) phenol}
And other benzotriazole-based UV absorbers; 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate, ethyl-2-cyano-3,3'-diphenyl acrylate, and other cyanoacrylate-based UV absorbers. . These ultraviolet absorbers may be used alone or in combination of two or more as required. The amount of the ultraviolet absorber used is preferably about 0.01 to 0.3% by weight in the transparent resin composition. Generally, when the amount of the ultraviolet absorber used is a small amount of less than 0.01% by weight, the effect of blocking the ultraviolet rays is not sufficient, whereas
If the amount is more than 3% by weight, the ultraviolet absorber may infiltrate the food from the transparent resin composition.

As the fluorescent whitening agent, various conventionally known fluorescent whitening agents can be used by appropriately selecting ones that are harmless to the human body. As an example, the following formulas (I-a to d)

[0010]

[Chemical 1]

A bisbenzoxazole-based optical brightening agent such as a compound represented by the following formula (II-a, b)

[0012]

[Chemical 2]

A naphthalimide-based optical brightener such as a compound represented by the following formula (III)

[0014]

[Chemical 3]

A pyrarizone-based optical brightening agent such as a compound represented by the following formula (IV-a, b)

[0016]

[Chemical 4]

Coumarin-based optical brighteners such as compounds represented by the following formulas (Va to c)

[0018]

[Chemical 5]

A diaminostilbene disulfonic acid-based optical brightener such as a compound represented by the following formula (VI)

[0020]

[Chemical 6]

An imidazolone-based optical brightener such as a compound represented by the following formula (VII)

[0022]

[Chemical 7]

Examples thereof include benzidine-based optical brighteners such as compounds represented by These optical brighteners may be used alone or in combination of two or more, if necessary. The amount of the fluorescent whitening agent used is preferably about 0.0001 to 0.05% by weight in the transparent resin composition. Generally, when the amount of the fluorescent whitening agent used is a small amount of less than 0.0001% by weight, the yellowing of the transparent resin composition cannot be sufficiently suppressed, while the amount thereof exceeds 0.05% by weight. And the transparent resin composition is too bluish,
After all, there is a possibility that it may cause a problem in appearance.

In the transparent resin composition of the present invention, in addition to the above-mentioned ultraviolet absorber and fluorescent whitening agent, if necessary, additives such as antioxidants, heat stabilizers, lubricants, antibacterial and antifungal agents are added. Can be added in an appropriate amount. As the above-mentioned various additives, those conventionally used in resin compositions in general, but those harmless to the human body can be appropriately selected and used. Examples of the above-mentioned antioxidant include phenol-based, amine-based, sulfur-based, phosphorus-based, and other antioxidants.
The amount added is 0.0 in the transparent resin composition.
It is preferably about 1 to 0.1% by weight. As an example of the above-mentioned phenolic antioxidant, 2,6-di-
tert-butyl-p-cresol (3,5-di-tertiary
Butyl-4-hydroxy-toluene), 2,4,6-tri-tert-butylphenol, n-octadecyl-3-
(4'-Hydroxy-3 ', 5'-di-tert-butylphenol) propionate, 4-hydroxy-methyl-2,6-di-tert-butylphenol, butylhydroxyanisole and the like can be mentioned. Further, examples of the amine-based antioxidant include phenyl-α-naphthylamine,
Phenyl-β-naphthylamine, N, N'-diphenyl-p-phenylenediamine, N, N'-di-β-naphthyl-p-phenylenediamine, N, cyclohexyl-N
′ -Phenyl-p-phenylenediamine and the like can be mentioned. Further, examples of the sulfur-based antioxidant include 2-
Examples thereof include mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dilauryl thiodipropionate, and distearyl thiodipropionate. Further, examples of the phosphorus-based antioxidant include tri (nonylphenyl) phosphite, 4,4-butylidene-bis (3-methyl-).
6-tert-butylphenyl-ditridecylphosphite), distearyl-pentaerythritol diphosphite, trilauritrithiophosphite and the like.

The transparent resin composition of the present invention can be prepared according to a conventional method for preparing a resin composition.
Add UV absorbers, fluorescent whitening agents, and additives such as antioxidants, heat stabilizers, lubricants, antibacterial and antifungal agents to the transparent resin of the base, Henschel mixer, open roll mixer, Banbury mixing It can be easily prepared by melt-kneading with a conventionally known kneader such as a kneader, a kneader, and an extruder. For example, it is convenient to prepare the transparent resin composition of the present invention in the form of pellets in advance, because the pellets can be molded into an arbitrary shape. In addition, each composition constituent component of the base transparent resin, the ultraviolet absorber, the fluorescent whitening agent, and if necessary, additives such as an antioxidant is directly supplied to a molding machine such as an extrusion molding machine, and molded. Needless to say, it is also possible to melt and knead in a machine to form a transparent resin composition and perform molding.

In using the transparent resin composition of the present invention as a base material for food container / packaging materials, for example, injection molding, extrusion molding, blow molding, vacuum / pressure molding, T-die, inflation, etc. are conventionally known. By the molding method, it can be molded into a container or packaging material having any shape, thickness, size such as bottle, box, film, plate, etc. It is not limited.

One example of the use of the transparent resin composition of the present invention as a base material for a container / packaging material for food is as follows: a sprinkle pack, a jelly confectionery container and a film-like lid thereof,
Examples include wraps for food packaging, food trays, bottles of beverages such as tea, cosmetic containers, medical / pharmaceutical containers, and the like. In particular, tea bottles have conventionally been colored green to prevent the tea from being deteriorated by ultraviolet rays. Therefore, there has been a situation that it cannot be melted together with other colorless and transparent beverage bottles for reuse. However, by adopting the transparent resin composition of the present invention, it becomes possible to recycle without having to separate it from other colorless and transparent bottles, which is preferable from the viewpoint of environmental protection.

[0028]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the invention is not limited thereto.

Example 1 Polypropylene [CX-50 (trade name), manufactured by Grand Polymer Co., Ltd.] was used as a base transparent resin, and 2- (2'-hydroxy-3'-tert-) as an ultraviolet absorber. Butyl-5'-methylphenyl) -5-chlorobenzotriazole [Adeka Stab LA-36 (trade name), manufactured by Asahi Denka Kogyo Co., Ltd.] is used and is represented by the above formula (Id) as a fluorescent whitening agent. 2,5-bis (5'-tert-butylbenzoxazolyl (2))
Using thiophene [UVITEX OB (trade name), manufactured by Ciba Specialty Chemicals], these are melt-kneaded by an extruder to obtain the above polypropylene 99.825.
A transparent resin composition having a composition of 10% by weight, 0.15% by weight of the ultraviolet absorber and 0.025% by weight of the fluorescent whitening agent was obtained.
A plate having a thickness of 1 mm was prepared using the obtained transparent resin composition, and the ultraviolet transmittance of the plate was measured. The result is shown in FIG. As is clear from the result of FIG.
It was proved that light in the ultraviolet region (about 400 nm or less) is hardly transmitted. The yellowness of the obtained transparent resin composition was measured and found to be 19.48. The yellowness of the plate formed of only the transparent resin as the base was measured in the same manner and found to be 15.33. From this, it is clear that the resin composition according to the present invention exhibits characteristics comparable to those of the case where only the transparent resin as the base is used.

(Example 2) In Example 1, except that the composition of the transparent resin composition was 99.65 wt% polypropylene, 0.3 wt% ultraviolet absorber, and 0.05 wt% fluorescent whitening agent. A transparent resin composition was obtained in the same manner as in Example 1. A plate having a thickness of 1 mm was prepared using the obtained transparent resin composition, and the ultraviolet transmittance of the plate was measured. The result is shown in FIG. As is clear from FIG.
It was proved that almost no ultraviolet light was transmitted. Also,
When the yellowness of the obtained transparent resin composition was measured, it was 1
It was 7.16.

(Comparative Example 1) In Example 1, no fluorescent whitening agent was used (the composition of the resin composition was 99.70 wt% polypropylene and 0.3 wt% ultraviolet absorber).
A resin composition was obtained in the same manner as in Example 1 except for the above.
When a plate was prepared from the obtained resin composition and the ultraviolet transmittance of the plate was measured, the transmittance in the ultraviolet to blue region was small, and the plate was visually yellowed.
The yellowness of the obtained transparent resin composition was measured and found to be 37.84.

[0032]

According to the present invention, there is provided a transparent resin composition for a food container / packaging material, which can prevent discoloration or deterioration of quality of food due to ultraviolet rays without being yellowed or impairing its appearance. It

[Brief description of drawings]

FIG. 1 is a diagram showing measurement results of ultraviolet transmittance of the transparent resin compositions obtained in Examples 1 and 2.

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Claims (2)

[Claims] 1. A transparent resin composition for food container / packaging material, which comprises a transparent resin containing an ultraviolet absorber and a fluorescent brightening agent. 2. The ratio of the ultraviolet absorber in the transparent resin composition is 0.01 to 0.3% by weight, and the ratio of the fluorescent whitening agent in the transparent resin composition is 0.0001 to 0.05% by weight. % Of food container according to claim 1, characterized in that
Transparent resin composition for packaging material.