JP3056562B2 - Easy peeling laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily peelable laminated film used for interleaving sheets and labels of communication postcards used to conceal transmitted information such as postcards, protect secrets, and prevent tampering. Things.

[0002]

2. Description of the Related Art Conventionally, as for an intervening sheet or label of a communication postcard capable of concealing transmitted information, a transparent film (polyester film, polypropylene film, etc.) made of a high melting point resin and a lower melting point than this are used. And
In addition, an ethylene-vinyl acetate copolymer or an ethylene-acrylic acid copolymer is provided on both front and back surfaces of a low-adhesion laminate film obtained by heat-sealing (pseudo-adhesion) both films of a transparent thermoplastic resin (eg, polyethylene). A concealment communication paper (postcard) or the like in which a four-layer laminated film provided with a heat-sensitive resin film layer is inserted into the opposing inner surfaces of the wrappable communication paper and sealed by pressing with a heat roll or the like. Proposed. The postcards and the like mailed in this manner are separated from the interface between the high-melting resin film and the low-melting resin film when the adhesive surface is peeled off, and since both films are transparent, the postcard and the postcard are opposite. The characters on both sides are readable.

Further, a sheet made of the above-mentioned four-layer transparent laminated film is bonded to a cover sheet having a hiding power by, for example, depositing aluminum on a resin film or paper, bonding aluminum foil, or applying an ink paste. A communication label or the like has been proposed in which a composite label is attached to a concealed information portion such as a postcard with heat, an adhesive, or the like to conceal transmitted information.

However, the quasi-adhesion point between the high melting point resin transparent film such as the interposition sheet and the composite label of the above concealment postcard and the low melting point film is an interface between the high melting point resin film and the low melting point polyethylene resin. After the third party peels off the concealed portion and easily reads the information described therein, the peeled surfaces are again overlapped, and the cover sheet shielding side,
Alternatively, since re-adhering is possible by applying heat, pressure, or the like from the communication paper side, there has been a problem that the party receiving the information cannot judge whether or not the information has leaked, which is not preferable. In addition, the pseudo-bonding strength between a transparent high-melting resin film and a polyethylene-based resin film is problematic in that the bonding strength increases as the manufacturing temperature or the outside air temperature rises, and the pseudo-bonded portion cannot be separated smoothly. was there.
In addition, these concealing intervening sheets and composite labels have a problem that the production cost is high because the number of laminations is large.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art relating to the pseudo-adhesive interposed sheet and the composite label. This makes it impossible to recover the information after reading it secretly, so that the information provider and the information receiver can exchange information with peace of mind, and one party receiving the information can immediately leak the information. In addition, the peel strength of the pseudo-adhesive surface can be kept below a certain level even when the temperature changes, and furthermore, by minimizing the number of layers of the interposing sheet for concealment and the composite label, the problem of curling can be reduced. An object of the present invention is to provide an easily peelable laminated film for preventing tampering, which can be manufactured at low cost.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a laminated film having an adhesive layer on at least a deposited film or a coating film of a substrate provided with a deposited film or a coating film. The adhesive strength at 20 ° C. is less than 200 g / 5 cm width, and the adhesive strength between the film and the adhesive at 20 ° C. is 200 g / 5 cm width or more.

One embodiment of the easily peelable laminated film of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a foldable sheet in which an adhesive layer 3 'is further provided on the back surface of an easily peelable laminated film 2 in which an adhesive layer 3 is provided on a deposition film or a coating film 8 provided on a substrate 4 of the present invention. A state in which a part of the communication paper that has been heated and pressed and adhered from both sides of the communication paper is sandwiched between the folded sides of the communication paper 1 with the printed or written communication items facing inward (see FIG. 2). FIG. 5 is a partially enlarged cross-sectional view showing a pseudo-adhesion interface at the interface between the base material 4 and the vapor-deposited film or the coating film 8, which is less than 200 g / 5 cm in width, and is peeled off from the interface. It is.

After the film is once peeled off from the interface, it does not adhere again even by heat or pressure, especially when a deposited film is provided on the substrate. In addition, since the deposited film or the coating film is generally very thin, characters and the like under the deposited film can be easily read through. Also, since a transparent synthetic resin film is generally used as the base material, Are also readable.

In the present invention, the adhesion strength between the deposited film or the coating film 8 and the substrate 4 is 200 g / at a temperature of 20 ° C.
It is essential that the width is less than 5 cm, and 200 g / 5 c
When the adhesive strength becomes not less than m width, the adhesive strength of the adhesive portion between the vapor deposition film or the coating film 8 and the base material 4 becomes stronger than the adhesive strength between the communication paper 1 and the base material 4, and when the communication paper itself is peeled off. A break occurs between the sheets, making it impossible to read the information written on the communication sheet, or separating at the interface between the communication sheet and the adhesive layer 3 so that the information cannot be read reliably. In the present invention, the more preferable adhesion strength between the deposited film or the coating film 8 and the substrate 4 at 20 ° C. is 5 to 100 g / 5 cm width, and the adhesion strength at 100 ° C. is also 5 to 200 g / 5 cm width.

The deposited film or the coating film used in the present invention may be, for example, a metal (aluminum, nickel, chromium, etc.) or a vitreous substance (oxidized titanium, tin, indium, silicon, aluminum, etc.). Magnesium, magnesium fluoride, etc.), and is formed on the substrate surface by vacuum processing such as sputtering and ion plating, in addition to normal vacuum deposition. Further, as the coating film forming agent, a silicone resin or a coating type liquid resin obtained by mixing colloidal silica with a resin aqueous emulsion or a resin adhesive solution is used. In addition, the thickness of the deposition material is generally 50 to 2,000.
Å, preferably in the range of 100Å-1000Å. The thickness of the coating film is 0.1-5 μm, preferably 0.3-1 μm.

Further, the substrate used in the present invention includes:
There are transparent films such as polyethylene, polypropylene, polyester, polystyrene, polyvinyl chloride, polyvinylidene fluoride and cellophane, and tracing paper.

The thickness of the substrate is usually about 6 to 100 μm, preferably about 9 to 50 μm, and the biaxially stretched resin film is more preferable because a thinner one can be used.

The adhesive layers 3, 3 'are made of low-density polyethylene having a melting point of 60 to 164 ° C., ethylene-acrylic acid copolymer,
Melt-extrusion lamination of an ethylene-vinyl acetate copolymer or the like on a vapor-deposited film or a coating layer 8 or a base material 4;
It is formed by applying and drying an acrylic resin solution or a polyvinyl acetate emulsion. The adhesive substance may have an adhesive strength of 200 g / 5 cm or more at 20 ° C. between the deposited film or the coating layer 8 or the substrate 4 and the communication paper, and the thickness is preferably 3 to 50 μm.

The adhesive layers 3 and 3 'may contain ordinary amounts of ordinary additives and auxiliaries, such as lubricants, antiblocking agents and antistatic agents. An uneven shape may be provided to improve blocking resistance and slipperiness. Further, in order to improve the adhesiveness between the adhesive layer and the communication paper surface or the like, for example, an oxidation treatment (corona treatment, ozone treatment, or the like) may be performed.

The communication paper 1 shown in FIGS. 1 and 2 of the present invention is, for example, pulp paper, coated paper, size-pressed paper, polyethylene laminated paper, etc., as well as synthetic paper, metal foil, metal vapor-deposited paper. It is made of a film or a laminate thereof, and the address, name, etc. of the recipient and sender are written on the outer surface of the two pieces of paper 1, 1 and the inner surface of the two pieces of paper is used for concealment. There is no particular limitation as long as the message can be printed.

The easily peelable laminated film of the present invention can be used as a label. That is, as shown in FIGS. 3 to 5, a pulp paper 5 or the like is attached to one piece of the vapor-deposited or coated film 4 with the above-mentioned adhesive layer 3 and has a shape smaller than that of a normal postcard. The information location can be sufficiently hidden. In addition, on the surface of this label 6, characters, printing,
Alternatively, a table, a graph, or the like may be printed.

The easily peelable laminated film of the present invention is used for communication paper 1
As a method of bonding the label 6 to the inner surface (FIG. 2) or the postcard 1 as a label 6 (FIG. 4), the adhesive layer is heated by hot air, a hot roll, or the like, and a heating / pressing roll provided with a constant roll interval and a pressure load. And press-fit.

In a communication postcard or a label for use of the present laminated sheet, a depth reaching the pseudo bonding portion 7 of the pseudo bonding body 5 is set within 2 to 5 mm inside the edge of one paper (1 or 1 '). A perforation or a slit may be provided so that the pseudo-adhesion portion 7 can be easily peeled off.

[0019]

On the sender's side, a laminated film having an adhesive layer on a vapor-deposited film or a coating film surface of a substrate provided with a vapor-deposited film or a coating film is placed on the inner surface of a double-folded or more folded communication paper on which concealment information is described, or On the receiving side, the communication postcard pasted as a label on the postcard is peeled off and developed at the interface between the deposited film and the deposited film, which is a pseudo-adhesive layer, and the deposited or coated film, and the deposited or coated film The concealment information can be read through.

Further, even if heat or pressure is applied, re-adhesion does not occur between the peeled and developed deposited film and the deposited film, and the deposited film transferred to the adhesive layer is not cracked. In such a case, information leakage can be immediately determined by the receiving side, for example, when an error occurs.

Further, since the concealment information is protected by a vapor-deposited film, a coating film, or a vapor-deposited or coated film, the influence of external friction, contamination, moisture and the like can be prevented.

[0022]

The tamper-proof laminated film of the present invention, by adopting the above structure, makes it impossible for a third party to secretly read information. It is excellent in that the receiving side can exchange information with peace of mind, and that the party receiving the information can immediately determine the leakage of information, it is excellent in keeping the peel strength of the pseudo-adhesive surface below a certain level, and furthermore, it is excellent for concealment postcards and labels. The number of laminations can be minimized, so that the curling problem can be solved and low-cost manufacturing can be achieved.

[0023]

【Example】

Example 1 Biaxially stretched polypropylene film having a thickness of 500 angstroms and having a deposited aluminum film (thickness: 25 μm)
Laminated film (15 μm / 500 ° / 25 μm / 15 μm) on both sides of which an ethylene-vinyl acetate copolymer resin (vinyl acetate content 20% by weight) was laminated as an adhesive layer.
m) was converted to a high-quality paper having an inner surface printed thereon (basis weight: 157 g /
m ² ), and put between double-folded communication paper sheets, and put between pressure rolls at a heating temperature of 125 ° C. and a rotation speed of 3 m / min to bond the communication paper and the adhesive layer to obtain a communication postcard. .

The obtained postcard for communication was cut to a width of 5 cm, and was cut between the aluminum vapor-deposited film and the surface of the biaxially stretched polypropylene film, between the biaxially stretched polypropylene film and the adhesive layer, and further between the adhesive layer and the high-quality paper. The adhesive strength and pseudo-adhesiveness, as well as anti-tampering properties and others (confirmation of concealment information, etc.) were evaluated, and the results are shown in the table.

Example 2 A coating material consisting of a toluene solution of an ethylene-vinyl acetate copolymer (Adcoat 33G-1A manufactured by Toyo Morton Co., Ltd.) was dried on both surfaces of the vapor-deposited film of Example 1 to a thickness of 5 μm. Then, an adhesive layer was formed by coating and drying at the following ratio, and a postcard for communication was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in the table.

Examples 3-4, Comparative Example 4 Communication was performed in the same manner as in Example 1 except that the type and thickness of the deposited film or coating film and the film to be deposited and the thickness thereof were changed as shown in the table. A postcard was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5 On both sides of a biaxially oriented polypropylene film coated on one side with a coating agent 0.5 g / m ² having the following composition,
A four-layer laminated film obtained by laminating an ethylene-vinyl acetate copolymer resin to a thickness of 15 μm was evaluated in the same manner as in Example 1, and the results are shown in the table. (A) Polymer-A: 100 parts by weight (b) Alcohol-dispersed colloidal silica (methanol silica manufactured by Nissan Chemical Co., Ltd.): 35 parts by weight (c) Polyoxyethylene lauryl ether (surfactant): 15 Parts by weight (d) Methanol: 450 parts by weight However, the polymer A in the active ingredient is the following component (e) to
This is a resin cord material obtained by reacting the mixed solution of (h) at 60 ° C. for 5 hours and neutralizing with a 20% aqueous ammonia solution. (E) 2-hydroxyethyl acrylate: 99 parts by weight (f) Acrylic acid: 1 part by weight (g) Azobisisobutyronitrile (reaction catalyst): 0.1 part by weight
5 parts by weight (h) methanol: 200 parts by weight

Example 6 Fine paper (52.3 g / basis weight)
m ² ) with an ethylene-vinyl acetate copolymer resin (thickness 15
μm), and a vapor-deposited laminated label obtained by laminating the same resin on the opposite vapor-deposited film surface was superimposed on the back side of the printed postcard, evaluated in the same manner as in Example 1, and the results are shown in the table.

Comparative Example 1 A three-layer laminated film in which an ethylene-vinyl acetate copolymer (vinyl acetate content: 20% by weight) was extrusion-laminated to a thickness of 15 μm on both sides of a polyethylene terephthalate film (PET) (thickness: 16 μm). Evaluation was performed in the same manner as in Example 1, and the results are shown in the table.

Comparative Examples 2 and 3 Polyethylene terephthalate film (16 μm thick)
A low-density polyethylene resin (melting point: 108 ° C.) having a thickness of 20 μm is laminated at 280 ° C. and 315 ° C. on one side, and then an ethylene-vinyl acetate copolymer (vinyl acetate content: 20% by weight) is coated on both sides of the laminated film. 15μ
The laminated film obtained by m-lamination was evaluated in the same manner as in Example 1, and the results are shown in the table. The laminated film was curled. When the laminated film was inserted into the inner surface of a double-folded communication paper and passed through a heat roll, the laminated film was partially thermally bonded in a bent state.

The adhesive strength between the layers is determined by cutting the obtained postcard or label for communication to a width of 5 cm, attaching a part which has been peeled off in advance with Tensilon to a chuck,
A value of 90 ° peeling was shown at a pulling speed of / min.

The pseudo-adhesion was evaluated by the following method at 20.degree. C. and 40.degree. C. on the peelability of the layer B and the layer C by hand. 〇: good △: heavy peeling ×: no peeling

The anti-falsification property was evaluated by passing the separated paper surfaces through a pressure roll at a temperature of 125 ° C. again. 〇 ・ ・ ・ No adhesion × ・ ・ ・ Re-adhesion

The concealment information was confirmed visually. 〇: Good △: Some characters are floating. ×: Cannot be confirmed. Aluminum deposited biaxially oriented polypropylene film (O
PP): Aluminum vapor-deposited polypropylene film (CPP) manufactured by Nimura Chemical Co., Ltd.
・ ・ Toyo Metallizing Aluminum evaporated polyethylene terephthalate film ・ ・ ・ Toyo Metallized silicon oxide evaporated polyethylene terephthalate film (12 μm thick) ・ ・ ・ Toyo Ink (GT film) Polyethylene terephthalate film (16 μm thick) ・
・ ・ Mitsubishi Resin Co., Ltd. (diafoil) Ethylene-vinyl acetate copolymer (EVA) ・ ・ ・ Mitsubishi Yuka (V401S) Ethylene-vinyl acetate resin coating agent ・ ・ ・ Toyo Morton Adcoat (33G-1A)

[0035]

【table】

[0036]

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view in which a part of a postcard, which is obtained by sandwiching the easily peelable laminated film of the present invention between two folded communication papers in which communication items are described on an inner surface thereof and pressure-heated and adhered, is peeled off.

FIG. 2 is a diagram showing a state in which the easily peelable laminated film of the present invention is inserted into a folded communication paper postcard.

FIG. 3 is a diagram showing a state in which a laminated film (label) of the present invention attached to the back of a postcard is peeled off.

FIG. 4 is a view showing a state in which a laminated film (label) of the present invention is stuck to a part to be concealed on the back surface of a postcard.

FIG. 5 is a diagram showing a state in which a laminated film (label) attached to the back of a postcard is peeled off.

[Explanation of symbols]

1. Communication paper, 2. Laminated film of the present invention, 3, 3 '...
Adhesive layer, 4 ... evaporated film film or coating film, 6
... label, 7 ... pseudo adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B32B 7/12 B32B 7/12 D21H 5/00 B

Claims (1)

(57) [Claims] 1. A laminated film having an adhesive layer (3) on at least a deposited film or a coating film of a substrate (4) provided with a deposited film or a coating film (8),
The adhesive strength between the deposited film or the coating film (8) and the substrate (4) is less than 200 g / 5 cm width at 20 ° C., and the adhesive strength between the film 8 and the adhesive layer 3 at 20 ° C. is 200 g.
An easily peelable laminated film having a width of / 5 cm or more.