JPH04135852A - Anti-fogging film for packaging foodstuff - Google Patents

Abstract

PURPOSE:To enhance favorable anti-fogging properties of the title film and improve the mechanical suitability of the same at the time of packaging foodstuffs therein by laminating a base film having printed layers and an anchor coating agent layer and a laminated film having a laminated layer and an outermost anti-fog layer to each other via molten polyethylene in such a way that the anchor coating agent layer and the laminated layer are opposed to each other and thus forming said film. CONSTITUTION:A base film 2 has printed layers 3 partly formed on one face of the base film and an anchor coating agent layer 4 formed over the entire surface of the base film on its face side where the printed layers are formed. A laminated film 6 has a laminated layer 7, an intermediate anti-fog layer 8 and an outermost anti-fog layer 9 which are all laminated in this order. When the base film 2 and the laminated film 6 are laminated to each other via molten polyethylene 5 in such a way that the anchor coating agent layer 4 is opposed to the laminated layer 7, an anti-fogging film for packaging foodstuffs is formed. The laminated layer 7 of the laminated film 6 consists of polyolefin and an ethylene alpha-olefin copolymer, and the intermediate anti-fog layer 8 consists of polypropylene or a propylene ethylene copolymer and a non-ion surfactant, while the outermost anti-fog layer 9 consists of the components of the abovementioned intermediate layer 8 and an inorganic filler.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an anti-fog film for food packaging, which is particularly suitable for machines such as food filling, and which is capable of reducing production costs in small quantity production. The present invention relates to a heat-resistant film for food packaging.

[Conventional technology]

BACKGROUND ART In recent years, various processed meat products, processed vegetable products, etc., packaged with food packaging films have been manufactured, and these products are generally placed in refrigerated or frozen showcases at stores and sold at low temperatures. However, when the food is exposed to low temperatures, the moisture contained inside the food and the moisture present on the surface of the food adhere to the inner surface of the food packaging film as water droplets, causing the food packaging film to become cloudy and causing the contents to become cloudy. There was a problem that it became difficult to recognize objects.

Therefore, by applying a surfactant to the innermost layer of the food packaging film or laminating a resin layer containing a surfactant to the innermost layer of the food packaging film, the inner surface of the food packaging film can be made hydrophobic. It has been attempted to prevent fogging of food packaging films by making them hydrophilic. However, the former coating method cannot be put to practical use due to processing steps, manufacturing costs, durability of the antifogging effect, etc., and the latter method of laminating resin layers containing a surfactant has been adopted. In this case, the base film layer constituting the food packaging film and the resin film containing a surfactant may be laminated together using a dry lamination method to form an antifogging film for food packaging, or an anchor coating agent may be applied in advance. A heat-resistant film for food packaging was formed by extrusion laminating a resin containing a surfactant on a base film layer.

[Problems to be Solved by the Invention] However, in the above dry lamination method, adhesion is inhibited due to bleed-out of the surfactant from the resin film containing the surfactant to the laminate surface, and it is expensive in terms of cost. Furthermore, although the extrusion lamination method is suitable for producing large lots of antifogging films for food packaging, it has the problem of increased production costs for small lots. In addition, anti-fog properties are imparted to food packaging films by bleeding out the surfactant from the resin layer containing the surfactant. There was also the problem that the slipperiness of the adhesive film was reduced, which hindered high-speed automatic filling of foods.

The present invention was devised in view of the above-mentioned circumstances, and provides a protective film for food packaging that exhibits good antifogging properties, has excellent mechanical suitability for food filling, etc., and is capable of reducing production costs in small-volume production. The purpose is to provide a cloudy film.

[Means to solve the problem]

In order to achieve such an object, the present invention provides a base film having a printed layer formed on at least a part of one surface and an anchor coating agent layer formed on the entire surface of the surface on which the printed layer is formed. , a laminate layer consisting of polyolefin and ethylene/α-olefin copolymer, polypropylene or propylene-ethylene copolymer (ethylene content 0.5 to 10% by weight), and one or more nonionic interfaces. A laminated film having an antifogging outermost layer consisting of an activator and an inorganic filler laminated in this order is melted so that the anchor coating agent layer of the base film and the laminate layer of the laminated film face each other. The structure is such that it is laminated with polyethylene interposed therebetween.

In addition, the laminated film has a polypropylene or propylene-ethylene copolymer (ethylene content: 0.5 to 10% by weight) and one or more nonionic interfaces between the laminate layer and the outermost antifogging layer. The structure includes an antifogging intermediate layer consisting of an activator and an activator.

[Effect]

The base film has a printed layer formed on at least a part of one surface thereof, and an anchor coating agent layer formed on the entire surface of the surface on which this printed layer is formed, and the laminated film has a laminate layer and The anti-fogging outermost layer is laminated in this order, and the base film and the laminated film are connected via molten polyethylene so that the anchor coating agent layer of the base film and the laminate layer of the laminated film face each other. By laminating, an antifogging film for food packaging is formed. The laminate layer of the laminated film is made of polyolefin and an ethylene/α-olefin copolymer, and the outermost anti-fog layer is made of polypropylene or a propylene-ethylene copolymer (ethylene content 0.5 to 10% by weight),
Since it is composed of one or more types of nonionic surfactants and inorganic fillers, the lamination of the base film and the laminated film via molten polyethylene has sufficient lamination strength, and the antifogging outermost layer can be The nonionic surfactant that bleeds out to the inner surface of the antifogging film for packaging shows good antifogging properties, and the nonionic surfactant bleeds out due to the inorganic filler contained in the outermost antifogging layer. It prevents deterioration in properties and has excellent mechanical suitability for food filling, etc., and can be adapted to small-lot production by laminating the required amount of the base film and the laminated film.

Furthermore, between the laminate layer and the outermost antifogging layer of the laminated film, polypropylene or a propylene-ethylene copolymer (ethylene content: 0.5 to 10% by weight) and one or more nonionic surfactants are added. By providing an anti-fog intermediate layer consisting of , the nonionic surfactant bleeds out not only from the outermost anti-fog layer but also from the anti-fog intermediate layer to the inner surface of the anti-fog film for food packaging, resulting in better anti-fog properties. gender is shown.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The figure is a schematic cross-sectional view showing an example of the antifogging film for food packaging of the present invention. In the figure, an anti-fog film 1 for food packaging includes a base film 2 on which a printed layer 3 is formed,
The anchor coat agent layer 4 provided on the surface metal area where the printed layer 3 of this base film 2 is formed, the polyethylene resin layer 5, and the anchor coat of the base film 2 via this polyethylene resin layer 5. It has a laminated film 6 laminated on the agent layer 4. The laminated film 6 has a laminate layer 7 made of polyolefin and an ethylene/α-olefin copolymer for adhesion to the polyethylene resin layer 5, and a laminate layer 7 made of polypropylene or a propylene-ethylene copolymer (ethylene content 0. 5-10
Anti-fog intermediate layer 8 consisting of (wt%) and a nonionic surfactant
and an antifogging outermost layer 9 made of polypropylene or propylene-ethylene copolymer (ethylene content: 0.5 to 10% by weight), a nonionic surfactant, and an inorganic filler. When food is packaged with this antifogging film 1 for food packaging, the outermost heat protection layer 9 becomes the inner layer. The anti-fog intermediate layer 8 causes the nonionic surfactant to bleed out to the inner surface of the anti-fog film 1,
The anti-fog outermost layer 9 has a non-ionic surfactant that bleeds out to the inner surface of the anti-fog film 1 and reduces the slipperiness of the anti-fog film 1 due to the non-ionic surfactant that bleeds out due to the inorganic filler it contains. It acts to prevent

The above-mentioned antifogging film 1 for food packaging is usually produced by melting a base film 2, on which a printed layer 3 and an anchor coating agent layer 4 have been previously formed on one side, and a laminated film 6 from a T-die. It is manufactured by the so-called sand lamination method, in which the product is laminated with extruded polyethylene resin. Therefore, the antifogging film 1 for food packaging can be manufactured using the base film 2 and the laminated film 6 in the amounts needed, and small-lot production becomes easy.

As the base film 2, stretched polypropylene, unstretched polypropylene, stretched polyethylene terephthalate, unstretched polyethylene terephthalate, stretched polyamide, unstretched polyamide, polycarbonate, cellophane, polyacetate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene- Films such as vinyl alcohol copolymers, or each of the above films with nitrified cotton,
A film coated with vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride, etc. is used. The thickness of the base film 2 can be appropriately determined depending on the usage pattern of the antifogging film 1 for food packaging, but is usually about 9 to 100 μm.

The printing layer 3 is formed on the above-mentioned base film 2 by back printing, and a known printing method such as a gravure method or a flexo method can be adopted depending on the base film 2 to be printed.

The anchor coating agent layer 4 provided over the entire surface of the base film 2 on the side where the printing layer 3 is formed is formed by applying an anchor coating agent such as isocyanate-based, polyethyleneimine-based, or organic titanate-based.

The polyethylene resin for laminating the laminated film 6 and the base film 2 on which the printing layer 3 and the anchor coating agent layer 4 are formed may be any of low density polyethylene, medium density polyethylene, and high density polyethylene. Good too.

The polyolefin in the laminate layer 7 constituting the laminate film 6 and the ethylene/α-olefin copolymer include polypropylene, low density polyethylene,
Medium density polyethylene, high density polyethylene, propylene-ethylene copolymer, -ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, polyto-2-butadiene, ionomer, etc. are used. However, polypropylene and propylene-ethylene copolymer are particularly preferred, and the ethylene content of the propylene-ethylene copolymer is 0.5 to 10% by weight.
degree is preferred. In addition, polyolefin and ethylene α
- The mixing ratio with the olefin copolymer is 0.2 by weight
It is preferable that it is 5-4. If the mixing ratio is less than 0.25, the production cost will increase due to the expensive ethylene/α-olefin copolymer, and if the mixing ratio exceeds 4, the adhesion between the laminate layer 7 and the anti-fog intermediate layer 8 mainly made of polypropylene will be reduced. The power becomes insufficient.

In addition, the nonionic surfactants in the heat protection middle layer 8 and the heat protection outermost layer 9 include sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, glycerin fatty acid ester, and oxyethylene/oxypropylene block copolymer. , polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol, etc., or two or more thereof can be used. Among these, the acid groups of fatty acid esters are generally lauric acid, palmitic acid, stearic acid, oleic acid, etc., and the ethers usually vary depending on the number of moles of ethylene oxide added, but are usually 4 to 4.
An additional mole of ether of 10 is used.

The content of the above-mentioned nonionic surfactant in the anti-fog intermediate layer 8 or the anti-fog outermost layer 9 is 3.
In the anti-fogging outermost layer 9, it is about 2000 to 4 oooppm. When the content in the anti-fog intermediate layer 8 is less than aoooppm, the nonionic surfactant bleeds out from the anti-fog intermediate layer 8 to the inner surface of the heat-proof film 1 is insufficient, and the content is less than 6000 ppm.
If it exceeds ppm, bleed-out will be excessive, and the anti-fogging outermost layer 9 will no longer be effective in preventing a decrease in slipperiness. Moreover, when the content in the anti-fog outermost layer 9 is less than 2oooppm, the total amount of nonionic surfactant bleed out from the heat-proof intermediate layer 8 and the anti-fog outermost layer 9 to the inner surface of the anti-fog film 1 is reduced. As a result, the desired anti-fogging properties are not achieved.
If the content exceeds 4oooppm, the inorganic filler will not be effective in preventing a decrease in slipperiness.

The method of mixing polypropylene and nonionic surfactant is
The two may be melt-blended in advance using a Banbury mixer, kneader, etc. to form a masterbatch at a predetermined mixing ratio, or the mixture may be directly mixed with a resin pellet.

In addition, as the inorganic filler contained in the heat protection outermost layer 9,
Silicon dioxide, zeilite, aluminosilicate, finely powdered takuru, etc. can be used.

The average particle size of such an inorganic filler is 0.3 to 15 μm.
degree is preferred. If the particle size is less than 0.3 μm, the effect of the present invention cannot be obtained unless the amount of inorganic filler added is increased.
If the amount added is increased, transparency will be lost and the particle size will be 1.
If it exceeds 5 μm, pinholes may be formed in the film or the film may be easily cut, which is not preferable. Further, the content of the above-mentioned inorganic filler in the antifogging outermost layer 9 is 1500 to 4
It is about 000 ppm. If the content in the outermost anti-fog layer 9 is less than 1,500 ppm, the inorganic filler will not be effective in preventing a decrease in slipperiness, and the content will be less than 4,000 ppm.
If it exceeds pm, transparency will deteriorate.

The method of mixing such an inorganic filler, polypropylene, and nonionic surfactant may be the same as the method of mixing polypropylene and nonionic surfactant described above.

The thickness of the anti-fog intermediate layer 8 to be formed is preferably about 5 to 50 μm, and the thickness of the outermost anti-fog layer 9 is preferably about 5 to 50 μm. The total thickness of the anti-fog intermediate layer 8 and the anti-fog outermost layer 9 is 10 to 100.
It is preferably about μm. If the total thickness is less than 10 μm, sufficient heat protection and slipperiness prevention effects cannot be obtained;
If it exceeds μm, an unnecessary amount of nonionic surfactant will bleed out.

In the embodiments described above, the laminated film 6 has a laminated layer 7
, an anti-fog intermediate layer 8 and an anti-fog outermost layer 9, but the anti-fog film for food packaging of the present invention has a laminated film 6 consisting of two layers: a laminate layer 7 and an anti-fog outermost layer 9. It may be a configuration.

In this case, the content of the above-mentioned nonionic surfactant in the outermost heat protection layer 9 is about 3000 to 4000 ppm. If the content in the outermost antifogging layer 9 is less than 3000 ppm, the total amount of nonionic surfactant bleed out from the outermost antifogging layer 9 to the inner surface of the antifogging film 1 will be insufficient, resulting in the desired antifogging. No properties are exhibited and the content is 4000
If it exceeds ppm, the inorganic filler will no longer be effective in preventing a decrease in slipperiness. Moreover, the thickness of the anti-fog outermost layer 9 is 10~
The thickness is preferably about 100 μm. If the total thickness is less than 10 μm, sufficient antifogging properties and anti-slip properties will not be obtained, and if it exceeds 100 μm, an unnecessary amount of nonionic surfactant will bleed out. (Experimental Example) Next, the present invention will be explained in more detail by showing an experimental example.

A stretched polypropylene with a thickness of 20 μm was used as the base film, a predetermined printing layer was formed on one side of the stretched polypropylene film by gravure printing, and further,
An organic titanate-based anchor coating agent was applied to the printing layer forming side to form an anchor coating agent layer.

In addition, polypropylene (Showa Denko Co., Ltd. Show Aroma)
and an ethylene/α-olefin copolymer (Tafmer manufactured by Mitsui Petrochemicals) in a ratio of 171, and the amounts shown in Table 1 below.

A laminate layer and an anti-fog intermediate layer were formed by coextruding polypropylene containing sorbitan monostearate (Showa Aroma, manufactured by Showa Denko K.K.).

Then, on the anti-fog intermediate layer, sorbitan monostearate and silicon dioxide (average particle size 4 μm) were added in amounts shown in Table 1 below.
A laminated film was formed by extruding polypropylene (Showa Aroma, manufactured by Showa Denko K.K.) containing m) as the outermost antifogging layer.

Next, the base film and the laminated film were laminated by melt-extruding low-density polyethylene to produce antifogging films for food packaging (Samples-1, 2, and 3).

In addition, polypropylene (Nyoaromer manufactured by Showa Denko)
A laminate layer was formed by extrusion molding a mixture of ethylene and α-olefin copolymer (Tafmer manufactured by Mitsui Petrochemical Co., Ltd.) at a ratio of 1/1. The above sample was used, except that polypropylene (Showa Aroma manufactured by Showa Denko) containing the indicated amounts of sorbitan monostearate and silicon dioxide (average particle size 4 μm) was extruded to form a laminated film as the outermost antifogging layer. - Heatproof film for food packaging (similar to 1, 2, and 3)
Samples 4, 5, 6) were manufactured.

For comparison, the content of sorbitan monostearate constituting the anti-fog intermediate layer and the content of sorbitan monostearate and silicon dioxide constituting the outermost anti-fog layer were as shown in Table 1. A heat-resistant film for food packaging (comparative samples-1, 2) was prepared in the same manner as the above samples-1, 2, and 3.
, 3) were manufactured.

Table 1 Each sample produced as described above was evaluated for antifogging properties and suitability for high-speed food filling under the following conditions.

The evaluation results are shown in Table 2.

Anti-fog property: 100mj of water at 35℃! Capacity 20 including
Cover the opening of a 0yrl beaker with the sample so that the outermost anti-fog layer faces the inside of the beaker, cool it at 5℃ for 10 minutes, then check the state of condensation on the sample surface (outermost anti-fog layer) and meet the following criteria. It was evaluated by

O...The entire surface is uniformly wet.

△...Large water droplets are attached.

×: There are cloudy areas due to the adhesion of fine water droplets.

・Suitability for high-speed food filling: The size of the bag after bag making is 14
Using a vertical pillow-type automatic filling and packaging machine with a length of 20 cm and a length of 20 cm, evaluation was performed based on the maximum number of sausages that could be packaged in 1 minute without sealing failure.

Table 2 As shown in Table 2, Samples 1 to 6 have good anti-fogging properties and are also suitable for high-speed food filling of 100 bags/100 bags/
This was more than 10 minutes, which was sufficient for high-speed filling. On the other hand, Comparative Sample 1 had good antifogging properties, but the antifogging outermost layer had low slipperiness and lacked suitability for high-speed food filling. In addition, Comparative Sample-2 had good suitability for high-speed food filling, but poor antifogging properties, and Comparative Sample-3
However, the anti-fogging property is poor, and the amount of sorbitan monostearate that bleeds out is large, causing wrinkles in the seal area during bag making. It was shown that the anti-fogging properties deteriorated.

〔Effect of the invention〕

As detailed above, according to the present invention, from the outermost anti-fog layer,
Alternatively, good anti-fog properties can be obtained by a nonionic surfactant that bleeds out from the anti-fog intermediate layer and the anti-fog outermost layer to the inner surface of the anti-fog film for food packaging, and an inorganic substance contained in the anti-fog outermost layer The filler prevents the deterioration of the slipperiness of the anti-fog film for food packaging due to bleed-out nonionic surfactant, making it highly suitable for machines such as food filling. Since it can be laminated, production costs can be reduced in small quantity production.

3...printing layer, 4... Anchor coat agent layer, 5... polyethylene resin layer, 6...Laminated film, 7... Laminate layer, 8...Heat protection middle layer, 9... Outermost heat protection layer.

Claims (1)

[Claims] 1. A printed layer formed on at least a portion of one surface;
A base film having an anchor coating agent layer formed on the entire surface of the printing layer side, a laminate layer made of polyolefin and an ethylene/α-olefin copolymer, and a polypropylene or propylene-ethylene copolymer. (ethylene content: 0.5 to 10% by weight), an antifogging outermost layer consisting of one or more nonionic surfactants, and an inorganic filler, laminated in this order. An antifogging film for food packaging, characterized in that the anchor coating agent layer of the base film and the laminate layer of the laminated film are laminated via molten polyethylene so as to face each other. 2. The laminated film contains polypropylene or propylene-ethylene copolymer (ethylene content 0.5-10% by weight) between the laminate layer and the outermost anti-fog layer.
2. The antifogging film for food packaging according to claim 1, further comprising an antifogging intermediate layer comprising one or more nonionic surfactants.