JP2918661B2 - Method for producing anti-fogging imparting easy-opening film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sealant for an easily-openable package that can be opened by peeling off a heat-sealed portion of a package that is filled with contents and packaged. The present invention relates to a method for producing a film having a layer provided with anti-fog properties.

(Prior Art) Conventionally, in a package to be filled with food or the like, an easily-openable package that can be opened by easily peeling off a heat-sealed portion to take out contents has been widely used.

And the above-mentioned easy-opening package, especially when the product is placed in a chilled stocker at about 5 to 10 ° C., the inside of the package becomes cloudy due to the outside cool air, the humidity and the air inside the package, and the content product There is a problem of a decrease in commercial value, such as disappearing.

In order to solve such a problem, a packaging material maker has generally generalized a method of applying a surfactant that is effective for wetting the inside and the surface of the sealant.

As a means for imparting a surfactant, generally, either a method of kneading the surfactant into a sealant or a method of applying the sealant to the seal surface is employed, but the method of maintaining the antifogging effect has a long lasting effect. In this respect, the kneading method is common.

The type of surfactant used is a nonionic surfactant which is compatible with plastics such as polyethylene, polypropylene or ethylene-vinyl acetate copolymer, which is most used as a sealant.

(Problem to be Solved by the Invention) The easily-openable sealant, which is an object of the present invention, is opened by peeling off the heat-sealed portion with the force of a human hand after sealing by heat sealing. It is a sealant that can heat seal strength is 500 ~ 1800g
It is adjusted by modifying the sealant resin etc. to about / 15 mm.

Modification of the sealant resin or the like can be achieved by various resin blends or additive blends such as an adhesive imparting agent, a lubricant, and an antiblocking agent.

Even if a surfactant effective for a general polyolefin resin is mixed with such a modified resin, an anti-fogging imparting easy-opening sealant which is satisfactory in terms of uniformity and durability of the effect is currently obtained. Not.

The reason for this is that the development of the anti-fog effect is said to be effective even when kneading, by bleeding to the uniform surface, as if the crystal structure is arranged on the surface. Since the sealant is modified with various resins, additives, and the like, it is assumed that a uniform bleed and a uniform crystal structure are hardly obtained.

Next, in the case of the coating method, a uniform surfactant crystal structure is certainly formed on the surface, and an excellent antifogging effect can be obtained.

However, the first problem with this method is the problem of the persistence of the effect as described above, and it is necessary to increase the coating amount of the surfactant in order to increase the sustainability. In this case, The biggest problem in the case of the easy-open sealant, as well as the surface sticking property, is a problem such as a large decrease in the seal strength with respect to the sealant adjusted to a low heat seal strength.

The present invention is intended to improve the above-mentioned drawbacks, without impairing the heat sealing property, and for obtaining an anti-fogging imparting easy-opening film which is extremely useful for an easy-opening package having an anti-fogging property. It is intended to provide a manufacturing method.

(Means for Solving the Problems) A means of the present invention for achieving the above-mentioned object is to provide a non-ionic surfactant in the innermost layer sealant of the package which can be opened by peeling off the heat seal portion by hand force. And a surfactant of the same or similar type is coated on the surface of the film to produce an anti-fogging imparting easy-opening film.

The amount of the incorporated nonionic surfactant is 0.5% by weight or less based on the innermost sealant film, and the amount of the applied nonionic surfactant is 0.5 g / m2.
² or less, and the nonionic surfactants are polyoxyethylene alkyl ether, polyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid It is composed of one or more of esters and polyoxyethylene alkylamines.

(Operation) The present invention configured as described above has the following operation.

Even with an easily-openable sealant film having a poor antifogging effect incorporating a surfactant, the same or similar surfactant is not hindered in the heat sealing property on the surface, and the minimum required to exhibit an antifogging effect. It is based on the research results that the antifogging effect can be remarkably maintained by surface-coating the surfactant in an amount.

The reason for this is that the surfactant layer having an anti-fog effect formed on the surface of the easily-openable sealant has a kind of priming effect and uniformly arranges the surfactant bleeding from the inside to prevent the effect. It can be assumed that the clouding effect is maintained.

It can be said that the kneading of the surfactant alone is a very useful action for an easily-openable sealant or the like in which an antifogging effect cannot be easily obtained, but the present invention is not limited to this theory.

(Example) Next, an example of a method for producing an anti-fogging property imparting easy-opening film according to the present invention will be described.

Easy-open sealant made of polypropylene and other resins such as polyethylene and ethylene-propylene rubber (A)
An easy-opening sealant (B) comprising an ethylene-vinyl acetate copolymer, a petroleum resin-based adhesion-imparting agent, an anti-blocking agent, a lubricant and the like will be described by way of examples.

(A) and (B) Both easy-open sealants are used as cover material sealant for polypropylene containers by sealing the flange portion of the container by heat sealing, and then opening the heat seal portion with the power of a human hand when opening. It is set to 1500-1800g / 15mm, which is the strength that can be opened in a container.

(A) can be used as an easy-open bag because it has a function of peeling off the portion even after heat sealing itself.

To give these easy-open sealants anti-fog properties,
An example in which a surfactant is provided will be described in detail with reference to Table 1 below.

The preparation of the sample and the measurement of the main physical property values were performed by the methods described below.

The mixing of the resin and the kneading of the surfactant were performed by blending with a blend mixer commonly used in the art, followed by compounding with an extruder set at an extrusion temperature of 200 to 230 ° C. to form pellets.

The resin was extruded at a temperature of 230 ° C. at an extrusion temperature of 50 μm using a T-die film casting apparatus widely used in the art.
Heat molding was performed.

Next, the molded film was treated with a 15 μm-thick biaxially stretched nylon film as a base material and an isocyanate-based primer treatment at an extrusion temperature of 320 ° C. with an extrusion laminator at a extrusion temperature of 320 ° C. and a low-density polyethylene having a thickness of 20 μm. The film was sandwiched to prepare a composite film of the substrate and (A) and (B).

Further, the surface of the sealant of the composite film was coated with a surfactant by a coating device.

The coating liquid used was diluted to a solid content of 10% with isopropyl alcohol. After coating, the coating liquid was sufficiently dried at a drying temperature of 80 ° C.

 Thus, a sample was prepared.

The anti-fog rating was 2 in a 130 ml polypropylene container.
/ 3 volume of hot water at 95 ° C. was injected, and this was heat-sealed using a cup sealer with the prototype sample. Thereafter, the sample was stored in a refrigerator, and the surface of the lid material was gradually removed. I checked the cloudiness.

The criteria for the judgment in the test were: 、: very good, ○: good,
Δ: Somewhat cloudy, ×: Very cloudy.

Similarly, the criterion for stickiness on the sealant surface is ◎:
Very good, ：: good, Δ: slightly sticky, ×: very sticky.

Heat seal strength, the cup seal strength for polypropylene container indicates (Kg / 15 mm), the sealing conditions are sealing temperature (180 ° C.) × sealing pressure (10 Kg / cm ²⁾ × sealing time (1.0 seconds), the measurement It was measured by a Tensilon tensile test at a width of 15 mm from the inside of the container.

As the surfactant, KF-1 (fatty acid ester / powder type) manufactured by Kawaken Fine Chemical Co., Ltd., which is a nonionic surfactant, is used for kneading, and KF-123 manufactured by the company is used for coating.
(Fatty acid ester, liquid) was diluted with isopropyl alcohol and used.

Regarding the physical properties of the resin used for the easy-open sealant (A), polypropylene (MFI = 18, at 230 ° C., d = 0.90), polyethylene (MI = 7, at 190 ° C., d = 0.92), ethylene / propylene rubber (MI = 8.0 , at 190 ° C, d = 0.88).

Regarding the physical properties of the resin used for the easily-openable sealant (B), an ethylene-vinyl acetate copolymer resin (MI = 15, at 190
° C, d = 0.94, vinyl acetate component = 15% by weight).

As the petroleum resin-based adhesive, an additive such as Alcon P-125 manufactured by Arakawa Hayashisan Co., Ltd., an antiblocking agent, a lubricant, and the like, which are widely used in the art for polyolefins, particularly for foods, were used.

In FIG. 1, reference numeral 1 denotes a surfactant-coated layer;
Denotes a surfactant kneading layer, and 3 denotes an anti-fogging imparting easy-opening film composed of the surfactant coating layer 1 and the surfactant kneading layer 2.

(Effect of the Invention) The anti-fogging imparting easy-opening film of the present invention obtained as described above is used in the field of easy-opening packaging such as lids, bags, etc. In tilt distribution, which is greatly affected by cloudiness and the like, it has applicability to a wide range of products in order to further stimulate consumers' willingness to purchase without impairing its product value.

Further, it is effective for solving the problem of partial discoloration due to uneven moisture adhesion to the product and for maintaining freshness of vegetables due to uniform dispersion of moisture inside the package.

Further, since a charge leakage effect is obtained by ionization of the water adsorbed by the surfactant, it can also be used for easily openable antistatic packaging such as molded containers and bags.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view showing one embodiment of an anti-fogging imparting easy-opening film employing a production method according to the present invention. In the figure, 1 is a surfactant-coated layer. 2 is a surfactant-kneaded layer. 3 is an anti-fogging imparting easy-opening film.

Claims (4)

(57) [Claims] 1. A nonionic surfactant is kneaded into the innermost sealant of a package which can be opened by peeling off the heat seal portion by hand force, and further, the same or similar surfactant is applied to the film surface. A method for producing an anti-fogging imparting easy-opening film, characterized by coating. 2. The amount of the kneaded nonionic surfactant is:
The method of claim 1, wherein the amount is 0.5% by weight or less based on the innermost sealant film. 3. The amount of the nonionic surfactant to be applied is 0.5 g.
/ m ² or less, the method for producing an anti-fogging imparting easy-opening film according to claim (1). 4. Nonionic surfactants include polyoxyethylene alkyl ether, polyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, The method for producing an anti-fogging imparting easy-opening film according to claim 1, wherein the polyoxyethylene alkylamine is one kind or two or more kinds.