JPH0420571A - Sheet or film for packaging food - Google Patents

Abstract

PURPOSE:To obtain the title sheet or film which has antibacterial, anti-fogging and antistatic properties and is safe even when in contact with foods by fabricating a thermoplastic resin having a small amount of a specified fatty acid monoglyceride mixture incorporated therein. CONSTITUTION:0.01-5wt.% mixture of octanoic acid monoglyceride and/or decanoic acid monoglyceride and lauric acid monoglyceride is incorporated into a thermoplastic resin (preferably a polyolefin, PVC or polyamide resin) to produce a sheet or film. This sheet or film is quite safe even when in contact with the human body and foods and has persistent antibacterial, anti-fogging and antistatic properties.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a food packaging sheet or film that has antibacterial, antifogging, and antistatic properties.

More specifically, the present invention relates to a sheet or film that has antibacterial, antifogging, and antistatic properties and is highly safe even when it comes into contact with food.

[Conventional technology]

Traditionally, food is packaged with Hatron paper or synthetic resin film to prevent contamination from dust and bacteria and to keep it clean, but it is proposed that this packaging material be treated with an antibacterial agent to further increase its effectiveness. has been done.

For example, paper impregnated with phenol-based or benzoic acid-based fungicides, and films impregnated with organic halogen-based or henzimidazole-based fungicides are manufactured, but they have drawbacks in terms of safety and efficacy. was there.

In addition, focusing on the fact that metal ions such as silver, copper and zinc have antibacterial properties, there are known methods of adhering or adding fine metal powders to polymer compounds, or methods of incorporating metal compounds into polymer compounds. There is.

One method is to make a polymer contain a functional group that has ion-exchange ability or a complex-forming ability, and have this functional group hold metal ions, but in this method, the interaction between the functional group and the polymer As a result, the physical properties of the polymer tend to change significantly, and the types of polymers that can be used and the types and amounts of functional groups that can be used are extremely limited.

On the other hand, there is a method in which metal ions with antibacterial effects are held in inorganic solid particles with ion-exchange ability, and these are added to a polymer (Japanese Patent Application Laid-Open No. 1-186804).
), agglomeration or uneven distribution of solid particles may cause variations in antibacterial activity, and may impair the physical properties of the polymer, such as flexibility and transparency. Further, a large amount (2 to 3% or more) of kneading is usually required for embedding or the like. In addition, especially for food packaging films, in addition to these antibacterial properties, it also improves the appearance and marketability, and also has anti-fog properties to prevent the formation of water droplets that can easily become a culture medium for bacteria, and to prevent adhesion such as flaking. Antistatic properties are required for food products, and there has been a strong desire for food packaging sheets or films that have both antifogging and antistatic properties as well as antibacterial properties.

[Problem to be solved by the invention]

The present invention improves the inadequacies of conventional technology, and provides films and sheets that have safe and long-lasting antibacterial activity, as well as anti-fog and antistatic properties, and maintain physical properties suitable for various uses. The purpose of the Company is to provide food packaging supplies such as containers processed from sheets.

[Means for Solving the Problems] The present invention provides octanoic acid monoglyceride, decanoic acid monoglyceride, and lauric acid monoglyceride (hereinafter each C
abbreviated as s, CIo and CI2. The present invention was achieved based on the discovery that sheets and films containing a mixture of (1) have excellent antibacterial, antifogging, and antistatic properties.

Fatty acid monoglycerides produced from edible fats and oils are such safe compounds that there are no restrictions on the foods in which they can be used or the amounts used as food additives. It is known that some of them have antibacterial properties, but nothing was known about their antibacterial properties when melted and mixed with thermoplastic resins.

The fatty acid monoglyceride used in the present invention is a mixture of either or both of C8 and 01° and 01□.

The amount used is 0.01-5% of the mixture based on the thermoplastic resin.
% by weight, preferably 0.1-3% by weight, particularly preferably 0.
It is 3 to 2% by weight. Below the lower limit, both antibacterial and antifogging effects are insufficient. Adding more than the upper limit is not preferable because it increases stickiness, which is unnecessary for practical antibacterial efficacy, and increases changes in physical properties of sheets and films.

Fatty acid monoglyceride C,,C,. The mixing ratio of CI2 is not particularly limited, but C6 or CIO or C8
+C,. The weight ratio of C1□ to C1□ is C,,C,. Or Cm + C + o: C + □ = 3.3 to 0.2:1, which exhibits excellent antibacterial properties and is preferred.

The optimal mixing ratio for antifogging properties differs depending on the environment near room temperature and the low temperature environment such as inside a refrigerator. C8 in environments above 10°C
and CIO are highly hydrophilic, so they are easily eluted and lose their antifogging properties in a relatively short period of time, so Cs, CIo or Cs
+clo: C+z=5 to 0.3:1 is preferred. At low temperatures below 10'C, hydrophobicity is emphasized and C
The elution of 8 is in the suppressed direction, but Cs, Coo or C
It is preferable to mix at a mixing ratio of a+Coo2C+z=10 to 0.3:l. Especially C.

CIO or Cs 10C+o: CIz=5~0.3
: A mixture ratio of 1 exhibits long-term antifogging properties over a wide temperature range commonly used.

The mixture of the present invention can be prepared by melt-mixing by a well-known method prior to melt-forming into a sheet, film, or the like.

The thermoplastic resin that can be used in the present invention is a polyolefin resin consisting of any one of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer, either alone or in a mixture thereof. The α-olefin of the ethylene-α-olefin copolymer has 4 to 10 carbon atoms and includes 1-butene, 1-pentene, and isobutyne.

3-methyl-butene-1,hexene-1,4-methyl-
Pentene-1, Heptene-1, Octene-1, Decene-1
etc.) Polyamide resins such as nylon 6 and Suilon 12, polystyrene resins such as polystyrene and ABS resins, vinyl resins such as polyvinyl chloride, polyvinyl acetate, and polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, and polycarbonate. .

Examples include polyacetal, polyether resins such as polyphenylene oxide, and polyurethane resins. Among these, polyolefin resins and polyvinyl chloride polyamide resins are preferred.

Any known method can be used to form the material into a sheet or film. In advance, the thermoplastic resin is uniformly kneaded using a Banbury-type mixer-shaft or multi-shaft kneading machine, etc., and processed by a normal molding method such as an inflation method, a T-die method, or a calendar method to impart other functions. Therefore, it can be multilayered by coextrusion or lamination with other sheets or films. Further, it is also preferable to perform tubular biaxial stretching or tenter biaxial stretching. The thickness usually used is 0.01~21! ll11, preferably 0
．． It is 03 to 1,5 ■.

In addition, plasticizers, heat stabilizers, antioxidants, fillers, lubricants, anti-bronching agents, ultraviolet absorbers, colorants, modifiers, etc. that are normally added to resins may be used as necessary. .

(Effect) The antibacterial activity of Cs, C1゜, and CI□ alone differs depending on the type of bacteria, but generally decreases in the order of C1l≧C3゜〉C72.However, when each is kneaded into resin, approximately CIl≦01゜〈 The order is C1□.

The reason for this is thought to be that although C8 and C4° are substances with relatively high boiling points, they still suffer considerable evaporation loss due to heat treatment when kneading into resin.

So C8, C,. Each alone or C8, C,.

C8 or C1 by adding CI2 to the mixture of
It is possible to suppress the volatilization of ゜ and significantly reduce the loss, and furthermore, the antibacterial spectra of Ce, C+o and CI□ work together in a mutually beneficial manner, thereby enhancing the antibacterial efficacy.

In addition, C8 and CIO have relatively high hydrophilicity, so Ca and C+ exist on the surface of the resin. is easily eluted by adhering water droplets, which reduces the antifogging effect; however, by mixing CI□, which has less hydrophilicity, elution can be suppressed, the antifogging effect can be enhanced, and the effective period can be extended.

The antistatic effect is due to the moderate surfactant effect of fatty acid monoglycerides.

[Examples] Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples.

Sample preparation The samples used in the examples were prepared by the following method.

(Sample of the present invention) Low density polyethylene (Mitsubishi Polyethylene F1 manufactured by Mitsubishi Chemical Corporation)
31 MFR = 1.3 ρ-0,924) 08 and 01□ were added to the crushed pellets at 1:21:3.3, respectively.
A composition in which C1° and C1□ were mixed in a weight ratio of 1:3.3:1, respectively;
A mixture of equal weights of 8 and 01° and C+z at 3:1
The compositions were mixed uniformly at a weight ratio of , and melt-kneaded using a twin-screw type kneader to prepare a 5% by weight master hatch. F this master hatch
131 pellets to contain 0.1%, 0.3%, and 0.5%, and a film with a thickness of 50 μm was obtained by an inflation method.

(Comparative sample) A sample with a thickness of 50 mm was prepared in exactly the same manner as above except that C, C, or C1□ was used alone as the monoglyceride.
A μm film was obtained.

Also, instead of monoglyceride, zeolite silver (abbreviated as X), paraoxybenzoic acid butyl ester (abbreviated as Y)
A film with a thickness of 50 μm was obtained in exactly the same manner as above except that .

(Sample without additives) Using an F131 pellet, the thickness was 5 mm using the inflation method.
A film of 0 μm was obtained.

Example-1 Using the above film sample, an antibacterial efficacy test was carried out in the following manner.

Antibacterial efficacy test method 5 taphylococcus aureus F
D A” 209P (Staphylococcus aureus) Bacillus cereus (Bacillus cereus) Escherichia coli T F O
3301 (Escherichia coli) was used, and an antibacterial test was conducted according to the revised AATCC-90 method. That is, each bacterium has a diameter of 8
5IIIIII The number of bacteria in a plastic tray is approximately 2.
The particles were adjusted to 5 x 10' pieces and uniformly dispersed and solidified on a 5 d ordinary agar medium.

A 25×25 body piece of each film sample was attached to the surface of this agar medium, and after culturing at 37° C. for 24 hours, the presence or absence of an inhibition circle was examined.

The results are shown in Table-1.

It has been shown that this method is much more effective than the comparative example. Furthermore, it can be seen that this result is effective not only on the film contact surface but also on the non-contact area.

Example 2 The film samples and bacterial strains described above were used and tested in accordance with the bacterial count measurement method of the Textile Hygiene Council.

Table 2 shows the results of sterilizing film samples using two methods: non-sterilization and autoclave sterilization at 121° C. for 920 minutes.

It can be seen that each example of the present invention is superior to the comparative example and has bacteriostatic (sterilizing) properties.

Example 3 An anti-fog test was conducted on the film sample prepared above.

For high temperature tests, fill a cup with water and adjust to 50±1°C. The film of Example 1 was covered and sealed on top of this, and the non-cloudy area of the film was expressed as a percentage for each elapsed time when the film was left in an environment of 23° C. and 150% RH.

The low-temperature state Q was measured by filling a cup with water, adjusting it to 18°C ± 1°C, covering it with the film of Example 1, sealing it, and leaving it in a refrigerator at 5°C. The area without area is expressed as a percentage.

The results are shown in Table 3. C8, C,. It can be seen that by mixing CI□ with CB, the antifogging property is improved more than when each of CB, CIO, and CI2 is used alone.

Example 4 Antistatic Efficacy Test Using the above film sample, the surface resistivity was measured in an environment of 23"C and 50% RH.

The implementation results are shown in Table-4. All exhibited good antistatic properties.

Back - 1 Antibacterial efficacy test (Hello Test Co., Ltd.) Table 2 Antibacterial efficacy test - Number measurement *Culture agent Ritsho Ikimachi volume table - 3 Anti-fogging test/test [Effect of the invention] The present invention has been shown to be effective against the human body and food. It is possible to provide a sheet or film for food packaging that has antibacterial, antifogging, and antistatic properties that are extremely safe even when in contact and exhibit long-lasting effects.

Claims (3)

[Claims] (1) Octanoic acid monoglyceride and/or decanoic acid monoglyceride and lauric acid monoglyceride are mixed at 0.0%.
1. A food packaging sheet or film comprising a thermoplastic resin containing 0.01 to 5% by weight. (2) The food packaging sheet or film according to claim 1, wherein the thermoplastic resin is a polyolefin resin, a polyvinyl chloride resin, or a polyamide resin. (3) The food packaging sheet or film according to claim 1, wherein the weight ratio of octanoic acid monoglyceride and/or decanoic acid monoglyceride to lauric acid monoglyceride is (10 to 0.3):1.