JP3162736B2 - Antibacterial stretch film for food packaging - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial stretch film for food packaging, and more particularly, to transparency, gloss, and the like.
The present invention relates to a stretch film for food packaging having excellent self-adhesiveness and having antibacterial properties.

[0002]

2. Description of the Related Art Stretch wrapping, in which fresh foods such as fruits and vegetables, fresh fish, meat, etc. are placed directly or on a plastic tray and wrapped while stretching a film, has been widely used with the development of supermarkets. Is now widely used as an indispensable packaging method. In recent years, this stretch packaging has taken a step beyond simply improving the product value by the display effect of food, preventing adhesion of various germs, etc. or preventing drying of the packaged item, and maintaining the freshness of the packaged item. It is also required to be done. In such a situation, for example, the viewpoint that freshness of the food can be maintained by sterilizing the packaging film or the container itself and the freshness of the food due to the volatilization of the antibacterial substance from the packaging film or the container itself are reduced. From the viewpoint that it can be maintained,
Suppresses the growth of microorganisms and supplies safe substances to appropriate articles,
For example, a method has been proposed in which various foods are adsorbed on various packaging materials and adhesives and the food is brought into contact with the food surface, or food is coated or packaged with such packaging materials (for example,
JP-A-61-108359, JP-A-2-3024
42, JP-A-2-302451, JP-A-2-302451
JP-A-2747763, JP-A-2-292201, JP-A-3-39363, JP-A-3-4345.
No. 6, JP-A-3-43457, Japanese Patent Application No. 1-3
No. 06734).

On the other hand, in general food packaging, silver, copper,
An antibacterial agent in which metal ions such as zinc, gold, and platinum are supported on an inorganic silicon compound or the like, for example, a film formed by kneading a composition in which an inorganic substance such as an antibacterial zeolite is kneaded with a thermoplastic resin has a large transparency. However, it has been difficult to add an additive amount sufficient to exert a sufficient effect. In particular, in the case of a stretch film for food packaging, properties such as transparency, gloss, and self-adhesiveness are important. However, conventional methods cannot sufficiently satisfy any of the properties and satisfy market requirements. (For example, see JP-A-3-34)
No. 851). As described above, a stretch film for food packaging which has been imparted with antibacterial properties without deteriorating the properties of the conventionally used stretch film for food packaging has not yet been proposed.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
To solve the above-mentioned problems of the conventional film, research was conducted to develop an antibacterial stretch film for food packaging having excellent transparency, gloss and self-adhesiveness. As a result, they have found that a film having a layer made of a specific resin or a resin composition containing hinokitiol or the like is suitable for the above purpose. The present invention has been completed based on such findings.

[0005] That is, the present invention relates to a method for preparing a low-density linear polyethylene and / or an ethylene-vinyl acetate copolymer or a resin composition containing these as a main component, by adding hinokitiol, a salt thereof, and a cyclodextrin clathrate containing them. Hinokitiol, a salt thereof, and a hinokitiol or a salt thereof comprising at least one layer containing at least one of these compounds and one or more resin compositions of an olefin polymer.
Do not contain any cyclodextrin inclusion compound
The present invention provides an antibacterial stretch film for food packaging characterized by being laminated with at least one of the following layers.

The hinokitiol, salts thereof and cyclodextrin clathrates containing them used in the present invention are preferably hinokitiol itself, alkali metal salts of hinokitiol such as sodium and potassium salts or hinokitiol-cyclodextrin clathrate. And hinokitiol-β-cyclodextrin clathrate. Hinokitiol, its salts and cyclodextrin clathrates containing them (hereafter, hinokitiols) can be sustained-released by incorporating them into stretch films for food packaging, which maintain antibacterial properties and reduce storage and operation problems. can do. However, it is not preferable to simply coat the film surface with hinokitiols, since the hinokitiols are present on the surface, volatilization proceeds during storage and operation, and sufficient self-adhesiveness cannot be obtained. Furthermore, in the present invention, the hinokitiols are converted to a linear low-molecular-weight compound in order to obtain an appropriate sustained release effect of the hinokitiols without impairing the transparency, gloss and self-adhesiveness required as a stretch film for food packaging. It is necessary to include the high-density polyethylene and / or ethylene-vinyl acetate copolymer or a resin composition containing these as a main component.

[0007] The content of hinokitiol such case this may be suitably selected according to various situations, preferably the film 1 m ² per 0.1～5000Mg (hinokitiol basis), more preferably 10～2000Mg, More preferably, it is 15 to 1000 mg. If this content is too small, the antibacterial effect is not sufficiently exhibited, while
If the amount is too large, the coloring and odor of the film are remarkably deteriorated, which is not practical. Further, the thickness of the stretch film of the present invention is not particularly limited, and may be determined as needed,
Preferably 8 to 30 μm, more preferably 8 to 20 μm
m. If the thickness of the film is too thin, the strength of the film will be low and the film will be broken after packaging. On the other hand, if it is too thick, the tray or the article to be packaged will be undesirably deformed during stretch packaging. Furthermore, the thickness of the layer containing hinokitiols also differs depending on the thickness of the entire stretch film and other conditions and cannot be unambiguously determined, but is preferably 1 to 10 μm, more preferably 2 to 10 μm.
6 μm. If this layer is too thin, it may be difficult to develop sufficient antibacterial properties. On the other hand, if it is too thick, the transparency tends to decrease, which is not practical.

Further, the stretch film of the present invention may have at least one layer containing hinokitiols, but preferably, it is located on the food side at the time of packaging, so that the antibacterial effect is enhanced. In addition, the layer containing hinokitiols does not necessarily need to be a film surface layer because hinokitiols are easily volatilized,
In order to enhance the basic characteristics of a stretch film for food packaging such as transparency, gloss and self-adhesiveness, a layer containing hinokitiols and a linear low-density polyethylene or ethylene-vinyl acetate copolymer as a surface layer Alternatively, it is preferable to laminate a layer made of a resin composition containing these as a main component.

As the linear low-density polyethylene used in the present invention, various copolymers can be used as long as they are copolymers of ethylene and an α-olefin.
0.910 g / cm ³ , preferably 0.870 to 0.900 g
/ Cm ³ and a melt flow rate at 190 ° C. of 0.1 to 10 g / 10 min, preferably 1 to 5 g / 10 min.
Minutes are given. Here, as the α-olefin, for example, 1-propene, 1-butene, 1-hexene,
3 carbon atoms such as 1-octene and 4-methyl-1-pentene
To 12 are preferred. If the density of the linear low-density polyethylene is too low, the strength properties are degraded, and if it is too high, uneven elongation occurs when the film is stretched at the time of packaging, and the transparency may be significantly reduced. Further, if the melt flow rate at 190 ° C. is too small, the productivity of the film is reduced, and if it is too large, there is a problem that the strength characteristics and the molding stability are reduced.

Further, the ethylene-vinyl acetate copolymer preferably has a vinyl acetate unit content of 5 to 3%.
0 wt%, more preferably 5 to 25 wt%, even more preferably 8 to 20 wt%, and a melt flow rate at 190 ° C of 0.1 to 10 g / 10 min, more preferably 1 to 5 g / 10 min. There are things. If the vinyl acetate unit content is too small, the flexibility, transparency, and deformation recovery properties are liable to decrease, and if it is too large, the strength properties are reduced. If the melt flow rate at 190 ° C. is too small, not only the elongation properties are reduced, but also the moldability is reduced, and if it is too large, the strength properties are reduced.

In the present invention, various resins and additives can be added to the above-mentioned resin as necessary in order to adjust flexibility, self-adhesion, anti-fogging property and the like. . Therefore, in the present invention, the linear low-density polyethylene and / or the ethylene-vinyl acetate copolymer or the resin composition containing these as a main component refers to the linear low-density polyethylene or ethylene as a main component as described above. -A vinyl acetate copolymer containing such various resins, additives and other auxiliary components as required. Such optional components include, for example, a rubber made of an ethylene-propylene copolymer or the like to adjust flexibility, and a moderate slip property, which is a characteristic basically required as a food packaging stretch film. The following additives can be used for imparting self-adhesiveness, antifogging property and antistatic property. That is, examples of the additive include sorbitan monooleate such as sorbitan fatty acid ester, glycerin fatty acid ester, and polyglycerin fatty acid ester, sorbitan monolaurate, sorbitan monobehenate, sorbitan monostearate, glycerin monostearate, and glycerin monostearate. Rate, glycerin monolaurate, glycerin monobehenate, diglycerin monolaurate, diglycerin monostearate, diglycerin monooleate, tetraglycerin monooleate, tetraglycerin monostearate, hexaglycerin monolaurate, hexaglycerin monooleate , Decaglycerin monolaurate, decaglycerin monostearate, decaglycerin monooleate, etc., but are not limited thereto. There. These fatty acid esters are used alone or as a mixed composition, but the amount of addition is usually 0.1.
It may be appropriately selected within a range of 1 to 5.0% by weight, preferably 0.5 to 3.0% by weight.

The stretch film of the present invention comprises a laminated film in which the above-mentioned layer containing hinokitiol and another layer not containing hinokitiol are laminated. Here, typical examples of the other layers to be laminated are layers for imparting or improving various characteristics required for a stretch film for food packaging, for example, tear strength, rupture strength, and heat resistance. Specifically, low-density polyethylene, ethylene-α-
One or more resins of olefin polymers such as olefin copolymer, propylene-α-olefin copolymer, ethylene vinyl acetate copolymer, crystalline polybutene-1, butene-1-ethylene copolymer, etc. A resin composition can be used. These other layers may have a single-layer structure or a multilayer structure obtained by combining them. By laminating these layers, a multilayer laminated film with a hinokitiol-containing layer is obtained. In particular, the above-mentioned other olefin polymer resin layer is used as a central layer, and one of the layers is a linear low-density polyethylene and / or
Alternatively, an ethylene-vinyl acetate copolymer or a hinokitiol-containing layer containing these as a main component is laminated, a layer containing no hinokitiol is laminated on the other layer, and a linear low-density polyethylene and / or ethylene is further added to the hinokitiol-containing layer. -A four-layer film obtained by laminating a vinyl acetate copolymer or a resin composition containing these as a main component is preferable because the film has good transparency, gloss and self-adhesiveness.

In producing the antibacterial stretch film for food packaging of the present invention, it can be produced by various known conventional methods employed in the production of general laminated films, especially stretch films for food packaging. . For example, it can be obtained by laminating and molding a resin composition to constitute each layer by a known method such as a co-extrusion method or an extrusion lamination method by inflation molding or T-die molding using a plurality of extruders. it can. Among them, the coextrusion method by inflation molding is preferred. Furthermore, the hinokitiol-containing layer can be easily contained by adding hinokitiol to the resin at the time of molding. Alternatively, a resin composition containing hinokitiols at a high concentration may be prepared in advance, and used after being diluted to a desired amount during molding.

[0014]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. Example 1 Ethylene-vinyl acetate copolymer (vinyl acetate unit content 15% by weight, melt flow rate at 190 ° C. 2.0)
g / 10 min) 80% by weight and polybutene-1 (density 0.9
15 g / cm ³ , melt flow rate at 190 ° C
2.0 g / 10 min) composition comprising 20% by weight and linear low density polyethylene (density 0.880 g / cm ³ , 190 ° C.)
A composition comprising 98.5% by weight of a melt flow rate and 3.5% by weight of a sorbitan monooleate, and a linear low-density polyethylene (density 0.880).
g / cm ³ , melt flow rate at 190 ° C. 3.5
g / 10 minutes) 98.0% by weight, sorbitan monooleate 1.
A composition comprising 5% by weight and hinokitiol 0.5% by weight was subjected to ethylene-vinyl acetate copolymer and polybutene-1 from three annular three-layer dies using three extruders each having a diameter of 50 mm and L / D = 26. Is blown at a resin temperature of 190 ° C. and a blow-up ratio of 4.5, and the thickness of each layer is 4 μm / 6 μm / 4.
A film having a thickness of 14 μm and a total thickness of 14 μm was obtained. Table 1 shows the evaluation results of this film.

The measurement and evaluation of the physical properties of each item were carried out by the following methods. 1) Melt flow rate; JIS K7210 2) Density; JIS K7112 3) Haze; JIS K6714 4) Gloss; JIS K7105 5) Self-adhesive; Was fixed to a plate with a tape and peeled up and down for measurement. 6) Preparation of antibacterial bacterial solution; (Bacillus subtilis)
After heating for a minute, the bacteria that grew on the standard agar medium were isolated and cultured on the agar slope (presumed to be Gram-positive bacteria). Pseudomonas putatively isolated and cultured on an agar slope (confirmed to be Gram-negative bacteria) Medium: 9 ml of standard agar medium is dispensed into test tubes in a test tube and sterilized. Keep in a safe place. Potato dextrose agar medium is dispensed into test tubes in 10 ml portions, sterilized, and kept at 45 ° C. Test; (1) 10 ml of medium (standard agar, potato dextrose agar) is poured into a petri dish and solidified. (2) 0.1 ml of the bacterial solution is added to (1), and the mixture is applied with a conical rod. (3) Take off the lid of the Petri dish of (2) and package it using the film of the example so that the antibacterial substance-containing layer is on the inside. (4) The petri dish of (3) is 35 ° C for Bacillus subtilis and 2 for low temperature bacteria.
Incubate at 1 ° C. Evaluation: The presence or absence of growth was compared with the control.

Example 2 Ethylene-vinyl acetate copolymer (vinyl acetate unit content: 15% by weight, melt flow rate at 190 ° C .: 2.0)
g / 10 minutes) 60% by weight and polybutene-1 (density 0.9
08g / cm ³ , melt flow rate at 190 ° C
1.0 g / 10 min) 40 wt% of a composition comprising ethylene-vinyl acetate copolymer (vinyl acetate unit content 18 wt%, melt flow rate at 190 ° C. 2.0 g / 10 min)
Min) 98.5% by weight and diglycerin monooleate 1.5% by weight, and an ethylene-vinyl acetate copolymer (vinyl acetate unit content 18% by weight, melt flow rate at 190 ° C. 2.0 g / 10 minutes) A composition comprising 93.5% by weight, 1.5% by weight of diglycerin monooleate and 5% by weight of hinokitiol was treated in the same manner as in Example 1 by using three extruders each having a diameter of 50 mm and an L / D = 26. Using a circular three-layer die, inflation molding was performed at a resin temperature of 190 ° C. and a blow-up ratio of 4.5 so that the composition comprising the ethylene-vinyl acetate copolymer and polybutene-1 became the central layer. Is 4 μm / 6 μm / 4 μm
A film having a total thickness of 14 μm was obtained. Table 1 shows the evaluation results of this film.

Example 3 Ethylene-vinyl acetate copolymer (vinyl acetate unit content: 15% by weight, melt flow rate at 190 ° C .: 2.0)
g / 10 min) 50% by weight, polybutene-1 (density 0.90)
8 g / cm ³ , melt flow rate at 190 ° C. 1.
0 g / 10 min) 30 wt% and propylene-ethylene random copolymer (ethylene content 7 wt%, melt flow rate at 230 ° C. 1.0 g / 10 min) 20 wt%
(A) comprising ethylene-vinyl acetate copolymer (vinyl acetate unit content 18% by weight, melt flow rate at 190 ° C. 2.0 g / 10 minutes) 98.5% by weight and diglycerin monooleate 1. Composition (b) consisting of 5% by weight, 93.5% by weight of ethylene-vinyl acetate copolymer (vinyl acetate unit content: 18% by weight, melt flow rate at 190 ° C. 2.0 g / 10 minutes) 93.5% by weight, diglycerin 1.5% by weight of monooleate and 5% by weight of hinokitiol
The composition composed of (c) was prepared by mixing the composition (b) / (c) /
A resin temperature of 190 ° C. and a blow-up ratio of 4.5 were obtained from four annular extruders using four extruders each having a diameter of 50 mm and L / D = 26 so as to obtain a four-layer configuration of (a) / (b). And the thickness of each layer is 2 μm / 4 μm
A film having a total thickness of 18 μm was obtained at / 6 μm / 6 μm /. Table 1 shows the evaluation results of this film.

Comparative Example 1 Ethylene-vinyl acetate copolymer (vinyl acetate unit content: 15% by weight, melt flow rate at 190 ° C .: 2.0)
g / 10 min) 80% by weight and polybutene-1 (density 0.9
15 g / cm ³ , melt flow rate at 190 ° C
2.0 g / 10 min) composition comprising 20% by weight and linear low density polyethylene (density 0.880 g / cm ³ , 190 ° C.)
The composition comprising 98.5% by weight and 1.5% by weight of sorbitan monooleate was mixed with two extruders each having a diameter of 50 mm and an L / D = 26 to obtain a ring 3 having a melt flow rate of 3.5 g / 10 min. From the layer die, inflation molding was performed at a resin temperature of 190 ° C. and a blow-up ratio of 4.5 so that the composition comprising the ethylene-vinyl acetate copolymer and polybutene-1 became the central layer, and the thickness of each layer was 4 μm / 6 μm.
A film having a thickness of / 4 μm and a total thickness of 14 μm was obtained. Table 1 shows the evaluation results of this film.

Comparative Example 2 Ethylene-vinyl acetate copolymer (vinyl acetate unit content: 15% by weight, melt flow rate at 190 ° C .: 2.0)
g / 10 min) 80% by weight and polybutene-1 (density 0.9
15 g / cm ³ , melt flow rate at 190 ° C
2.0 g / 10 min) Composition (d) consisting of 20% by weight, linear low density polyethylene (density 0.880 g / cm ³ , 1
Melt flow rate at 90 ° C 3.5 g / 10 min) 9
A composition (e) consisting of 8.5% by weight and 1.5% by weight of sorbitan monooleate, and a linear low-density polyethylene (density 0.880 g / cm ³ , melt flow rate at 190 ° C. 3.5 g / 10 minutes) ) A composition (f) consisting of 96.5% by weight, 1.5% by weight of sorbitan monooleate and 2% by weight of an antibacterial zeolite was prepared with a 50 mm diameter, L / D =
(E) / (d) /
(F) The resin temperature is set to 19 from the annular three-layer die.
Inflation molding at 0 ° C, blow-up ratio 4.5,
Each layer has a thickness of 4 μm / 6 μm / 4 μm and a total thickness of 14 μm
m was obtained. Table 1 shows the evaluation results of this film.

[0020]

[Table 1]

[0021]

As described above, the antibacterial stretch film for food packaging of the present invention has excellent antibacterial properties. In addition, it has excellent transparency, gloss and self-adhesiveness, which are the basic characteristics of a stretch film. For example, it has better transparency and transparency than a film in which an inorganic substance such as an antibacterial zeolite is kneaded with a thermoplastic resin. It has gloss and self-adhesiveness. Furthermore, since hinokitiols volatilize appropriately from the film, they can exhibit antibacterial properties even if the food does not necessarily come into contact with the film. Therefore, the antibacterial stretch film for food packaging of the present invention can be effectively used for packaging various foods such as fresh foods such as fruits and vegetables, fresh fish, meat, etc., and has a great practical value as a highly practical film.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C08K 5/05 C08K 5/05 C08L 23/04 C08L 23/04 31/04 31/04 // C08L 23:04 31:04 (72) Invention Ritsutaro Fukazawa 4-19-10 Shozuzawa, Itabashi-ku, Tokyo Seiwa Kasei Co., Ltd. (56) Reference JP-A-61-108359 (JP, A) JP-A 1-245058 (JP, A) JP JP-A-58-101133 (JP, A) JP-A-55-81155 (JP, A) JP-A-56-20042 (JP, A) JP-A-55-51537 (JP, A) JP-A-1-135355 (JP, A) JP-A-1-211446 (JP, A) JP-A-1-166954 (JP, A) Patent 2849586 (JP, B2) Patent 3068235 (JP, B2) JP-A-8-3277 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J 5/18 CES A23L 3/00 101 B32B 27/18 B32B 27/32 B65D 81/24 C08L 23/04 C08L 31/04 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. One or more of hinokitiol, a salt thereof and a cyclodextrin clathrate containing the same in a linear low-density polyethylene and / or an ethylene-vinyl acetate copolymer or a resin composition containing these as a main component. At least to one layer which contains a compound, comprising an olefin polymer one or more kinds of resin compositions, Hino
Chithiols, their salts and cyclodextrins containing them
An antibacterial stretch film for food packaging, characterized by laminating at least one layer not containing any of the phosphorus clathrate compounds . 2. A linear low-density polyethylene and / or
Tylene-vinyl acetate copolymer or containing these as a main component
Hinokitiol, its salts and containing them in the resin composition
Formation of one or more cyclodextrin inclusion compounds
The olefin-based polymer is applied to both sides of the layer containing the compound.
Hinokiti comprising one or more resin compositions of the body
Oars, their salts and cyclodextrins containing them
At least one layer not containing any of the clathrates
The food package according to claim 1, wherein the food package is laminated.
Wearable antibacterial stretch film. 3. The content of one or more of hinokitiol, salts thereof and cyclodextrin clathrates containing them is 0.1 to 5000 m ² per m ^{2 of} film.
g (in hinokitiol conversion), The antibacterial stretch film for food packaging of Claim 1 or 2 characterized by the above-mentioned. 4. The method according to claim 1, wherein the layer containing at least one compound selected from the group consisting of hinokitiol, salts thereof and cyclodextrin clathrates containing them is 1 to 10 μm in thickness . The antibacterial stretch film for food packaging according to any one of the above. 5. A linear low-density polyethylene having a melt flow rate of 0.1 to 10 g / 10 min at 190 ° C. and a density of
Food packaging antibacterial stretch film according to claim 1 or 2, characterized in that a 0.860~0.910g / cm ^3. 6. An ethylene-vinyl acetate copolymer having a content of 190
The antimicrobial stretch film for food packaging according to claim 1 or 2, wherein the melt flow rate at 0.1C is 0.1 to 10 g / 10 minutes and the vinyl acetate unit content is 5 to 30% by weight.