JPH05178332A - Applying method for heat sealable resin - Google Patents

Abstract

PURPOSE:To form a heat seal material having a given shape and a given area with high precision by a method wherein a laminate having a base material to which a heat sealable resin layer is formed is superposed with a part intended to produce a heat seal surface of a pack material, and heat transfer is applied on at least a part of the heat sealable resin layer. CONSTITUTION:A laminate 5 wherein the laminate comprises a base material 3 and a heat sealable resin layer 4 and when heating or peal after heating, the heat sealable resin layer 4 has cohesive failure properties or the heat sealable resin layer 4 and the base material 3 indicate interlayer rupture is prepared. The laminate 5 is superposed with a cup-form container 1 in a position relation in which the heat sealable resin layer 4 is positioned facing a flange 2, and a hot plate 6 having an area conforming to that of the heat seal part is pressed and heated. Thereafter, the hot plate 6 is removed and by removing the laminate 5 from the flange 2, a part 7 where the heat sealable resin layer 4 is positioned facing the hot plate 6 is thermally transferred to the flange 2 to form the heat sealable resin layer having a given shape and a given area is formed in a given position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a heat-sealable resin layer to a packaging material, and more specifically to a method for applying a heat-sealable resin layer to a packaging material using thermal transfer, and particularly Easy-to-peel properties that packaging materials originally do not have,
The present invention relates to a method of imparting properties such as low-temperature sealability and heat-sealability with a different resin to an arbitrary place where it is required.

[0002]

2. Description of the Related Art The sealing technique by heat sealing is widely used for sealing various containers such as a plastic container, a plastic-metal foil composite container, a metal can and a glass bottle. It is possible to use a lid provided with a sealing material layer, a container provided with a heat sealing material layer on the entire inner surface, or a container coated with a heat sealing material on the peripheral portion to be heat sealed. It is being appreciated.

Olefin resins such as polyethylene and polypropylene and resin compositions containing these olefin resins are excellent heat seal materials. However, in order to apply this resin only to the portion of the container or lid to be heat sealed, It is necessary to apply the resin in the form of powder, dispersion, solution or the like, or to punch the film of the resin into a shape corresponding to the heat seal portion, for example, a ring shape, and apply this to the portion to be heat sealed. Becomes

Japanese Patent Application Laid-Open No. 1-99
No. 330 discloses a method of circumferentially applying a layer of a heat-sealing material to a container or a lid to be heat-sealed, wherein the heat-sealing material resin has a size slightly larger than the outer dimensions of the container or the lid. A shrinkable tubular film is prepared, and the tip of the tubular film is projected outward from the mold corresponding to the container, the lid, or the heat-sealing portion thereof by an amount corresponding to the heat-sealing width, and the tube-shaped film By heating and shrinking the protruding portion, a circumferential heat-sealing layer is formed along the heat-sealing surface, and the heat-sealing layer is adhered to a container or a lid. And a method of circumferentially applying a layer of heat-sealing material to a container or lid to be heat-sealed, the heat-shrinkability comprising a heat-sealing material resin having a width slightly larger than the heat-sealing width of the container or lid. Prepare the tape of this tape Wrap the tape around the outer periphery of the mold corresponding to the container, lid, or their heat-sealing part so that only the part corresponding to the heat-sealing width protrudes outward, and then fix the protruding part of the tape to shrink it. Describes a method for applying a heat-sealing material, which comprises forming a circumferential heat-sealing layer along the heat-sealing surface and adhering the heat-sealing layer to a container or a lid.

[0005]

However, in the method of applying the heat-sealing material in the form of powder, dispersion or solution, the heat-sealing material layer by this method has a large variation in thickness, and the heat-sealing material layer is further formed. Film defects such as pinholes are likely to occur. Further, in the method using a solvent, the heat-sealable resin is limited to those having solubility, or the solvent odor remains in the heat-sealable resin layer formed, or other parts are contaminated with the solvent. And because it goes through an oven to remove the solvent,
There is a problem that applicable packaging materials are limited to those which are heat stable.

On the other hand, the method of punching a film and applying it eliminates the above-mentioned drawbacks of the powder or dispersion or solution coating method, but it causes a step at the part to which the film is applied and limits the cut shape of the film. That there is
A flexible or flexible heat-sealing material layer must be applied to the container or the lid in a precisely positioned state, which is troublesome in operation and difficult to apply to a narrow portion. I'm not satisfied.

By the way, it is necessary to apply a heat-sealing material only to the portion of the container or lid to be heat-sealed, which is necessary in the case of an internally coated metal container or a glass container. As described in Japanese Patent Publication No. JP-A-2003-264, a container in which opposing portions of a plurality of container materials are hermetically sealed by heat sealing, and at least an unsealing start portion of the sealing portion is inserted between the plurality of container materials. Having an intermediate material and a laminated structure, one of the intermediate material and one of the plurality of container materials is a tight seal, and the other of the intermediate material and the plurality of container materials is an easily-openable seal. The inner peripheral side edge is located closer to the center side than the inner peripheral side edge of the tight seal part, and the outer peripheral side edge of the easy-open seal part is at the outer peripheral side edge of the tight seal part at the opening start position. Same position There is also required to produce the easily openable sealed food containers, characterized in that in the center side thereof.

An object of the present invention is that the heat-sealing material can be accurately applied to a predetermined shape, area and thickness by heat transfer only on the portion of the container or the lid to be heat-sealed. It is another object of the present invention to provide a method capable of imparting properties such as easy peeling property, low temperature sealing property, and heat sealing property with different kinds of resins which cannot be originally provided to any place where it is required.

Another object of the present invention is to provide a heat-sealant resin or resin composition having various functions with excellent workability in a container or a container without any restrictions on film-forming property on a film or solubility in a solvent. It is to provide a method applicable to any heat-sealing surface of a packaging material such as a lid.

[0010]

According to the present invention, the heat-sealable resin layer is composed of a substrate and a heat-sealable resin layer and has cohesive failure or heat-peelability upon heating or peeling after heating. A laminate in which the sealable resin layer and the substrate exhibit interlaminar destruction is superposed on a packaging material in a positional relationship where the heat-sealable resin layer and a portion to be the heat-sealing surface of the packaging material face each other, Provided is a method for applying a heat-sealable resin, which comprises thermally transferring at least a part of the heat-sealable resin layer of the laminate to a portion of the packaging material to be a heat-seal surface.

The heat-sealable resin layer used in the present invention is
In order to exhibit various functions, it is preferable that it is composed of a blend of two or more kinds of resins, and in particular, one component of the blend exhibits a heat-sealing property to at least one of the packaging material surface and the heat-sealed material. Component, the other component of the blend is an easily peeling imparting resin component, or one component of the blend is a resin component showing heat sealability to the packaging surface, and the other component of the blend Is preferably a resin component having heat sealability with respect to the material to be heat sealed.

Further, the heat-sealable resin layer is made of a copolymer containing a monomer component common to the resin constituting at least one of the packaging material surface and the heat-sealed material. It is preferable with respect to the retention of the resin layer.

[0013]

In FIG. 1 for explaining the principle of the present invention,
The packaging material on which the heat-sealable resin layer should be applied is the cup-shaped container 1
Flange 2 of. First, in step A, for application of the heat-sealable resin layer, the heat-sealable resin layer 4 is composed of the substrate 3 and the heat-sealable resin layer 4 and has cohesive failure property at the time of heating or peeling after heating. Alternatively, a laminate 5 in which the heat-sealable resin layer 4 and the substrate 3 exhibit interlaminar destruction is prepared. Next, in step B, the laminated body 5 is superposed on the cup-shaped container (packaging material) 1 in a positional relationship in which the heat-sealable resin layer 4 and the flange (portion to be the heat-sealing surface of the packaging material) 2 face each other. In addition, the heat plate 6 having an area corresponding to the heat seal portion is pressed and heated from the base body side of the laminate. Finally, in step C, when the hot plate 6 is removed and the laminated body 5 is removed from the flange 2, the portion 7 of the heat-sealable resin layer 4 corresponding to the hot plate 6 becomes the flange 2.
By heat transfer to, a heat-sealable resin layer having a predetermined shape and a predetermined area is formed at a predetermined position.

In the present invention, the heat-sealable resin layer can be thermally transferred from the substrate side to the predetermined surface of the packaging material because the adhesive strength of the heat-sealing resin to the packaging material is the cohesive force of the heat-sealing resin layer or the heat-sealing resin. Although the property of being larger than the interlayer adhesive force between the layer and the substrate is skillfully utilized, in the present invention, as a combination of the heat-sealable resin layer and the substrate, heat sealing is performed at the time of heating or peeling after heating. The heat transfer of the heat sealable resin layer is made possible by selecting one having a cohesive failure property as the heat resistant resin layer or by selecting one having the interlayer breakability between the heat sealable resin layer and the substrate.

Whether the heat-sealable resin layer is subjected to cohesive destructive thermal transfer or interlaminar destructive thermal transfer largely depends on the composition and properties of the heat-sealable resin layer and the combination with the substrate. For example, in general, the relationship between the cohesive force (Ta) of the heat seal resin layer and the interlayer adhesive force (Tb) between the heat seal resin layer and the substrate is expressed by

When the relationship of Ta ≦ Tb is established, cohesive failure occurs inside the heat-sealable resin layer of the laminate, and interlayer destructive thermal transfer of the heat-sealable resin layer occurs. On the other hand, the formula

When the relationship of Ta> Tb is established, interlayer breakage occurs between the substrate and the heat-sealable resin layer, and the heat-sealable resin layer is subjected to interlayer destructive thermal transfer. From the standpoint of thermally transferring the heat-sealable resin layer to a reliably set thickness, it is preferable to satisfy “Equation 2”.

In the present invention, the use of thermal transfer in applying the heat-sealable resin to the portion to be the heat-sealing surface of the packaging material is very reasonably related to the final heat-sealing operation. It can be called a purposeful and purposeful method. That is, since the heat-sealing surface of the packaging material is a portion to which the other material to be heat-sealed is originally applied to this packaging material and a heating mechanism for heat-sealing such as a heat-seal bar comes into contact with or acts on, Similarly, the operation, device, control means and the like for sealing can be similarly applied to the heat transfer of the heat-sealable resin layer to the packaging material, which provides an advantage that the operation is reliable and easy. Further, in the present invention, not only can the heat-sealable resin layer be applied as a layer that is accurately positioned and has an accurate area and thickness, but there is no defect such as flavor reduction due to residual solvent, and heat-sealing is possible. The advantage that there is no step or wrinkle in the flexible resin layer is also achieved.

From another point of view, it is possible to provide a necessary function even if the container base does not have a complicated multi-layered structure, or even when the multi-layered structure is difficult. In addition, a heat-sealable resin that is difficult to form into a film, or even a heat-sealable resin having a material and a thickness that cannot be handled as a single film,
There is also an advantage that it can be applied as a required minimum thin film state by laminating it on a substrate.

[0018]

Preferred Embodiment of the Invention

(Heat Transfer Material) The heat transfer material for applying the heat-sealable resin layer to the packaging material comprises a substrate and a heat-sealable resin layer applied on the substrate. The combination of the substrate and the heat-sealable resin layer is one in which the heat-sealable resin layer has cohesive failure property at the time of heating or peeling after heating, or the heat-sealable resin layer and the substrate show interfacial destructive property. Must.

The substrate is a metal foil such as aluminum foil, tin foil, steel foil, tin foil, etc., or a heat resistant resin film such as biaxially oriented polyethylene terephthalate film, biaxially oriented nylon film, polycarbonate film or polypropylene film. It is made of a thermoplastic resin film, various papers, or a laminate of these.

The heat-sealable resin layer is generally low-,
Medium-, high-density polyethylene, linear low-density polyethylene, isotactic polypropylene, propylene-
Ethylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ion-crosslinked olefin copolymer (ionomer), ethylenically unsaturated carboxylic acid or its anhydride Modified olefin resin such as olefin resin graft-modified with styrene; polyamide or copolyamide resin having a relatively low melting point or low softening point; polyester or copolyester resin having a relatively low melting point or low softening point; It consists of the above combinations. Further, various fillers may be blended with these heat seal resins in order to impart cohesive failure and prevent stringing at the time of transfer. For example, titanium oxide, talc, mica, etc. are preferably applied as the filler for the inorganic thread.

The material to be specifically used is appropriately selected depending on the types of the packaging material, the substrate of the thermal transfer material, and the material to be heat-sealed (material to be heat-sealed later). That is, basically, the heat-sealable resin layer has a strong heat-seal property with respect to materials made of the same kind of resin. Thus, as the heat-sealable resin layer, when a copolymer containing a monomer component common to the resin constituting at least one of the packaging material surface and the heat-sealing material is used, the packaging material surface and the heat-sealing material Heat sealing (including thermal transfer) can be performed between at least one of them.

Further, a modified olefin resin such as an olefin resin graft-modified with an acid or an acid anhydride can be heat-sealed with respect to an olefin resin having no polar group, as well as having a polar group. It exhibits excellent heat-sealing properties to other members such as metal foil, paper, polar group-containing resin films such as polyester and polyamide.

The heat-sealable resin layer used in the present invention is
Of course, it can be used as a single resin, in order to impart various functions to this heat-sealable resin layer,
It is preferable to use a plurality of types of resin compositions or a plurality of resin layers. As a combination of this composition,
The following examples can be given as examples of the multilayer resin layer, but the present invention is not limited to this example.

(1) One component of the blend is a resin component showing heat sealability to at least one of the packaging material surface and the heat-sealed material, and the other component of the blend is a resin component imparting easy peeling property. What is. This composition is advantageously used to form an easily peelable heat seal. For example, with respect to polypropylene, a propylene resin acts as a heat-sealable component, and an ethylene resin acts as an easily peelable component. On the contrary, with respect to polyethylene, the ethylene resin acts as a heat-sealable component and the propylene resin acts as an easily peelable component. When the acid-modified olefin resin is the heat-sealable resin component, the unmodified olefin resin acts as an easily peelable component.

(2) One component of the blend is a resin component having heat sealability with respect to the packaging material surface, and the other component of the blend is a resin component having heat sealability with respect to the heat-sealed material. What is. This composition is useful for different packaging surfaces and heat-sealed materials. For example, when the surface of the packaging material is polypropylene and the material to be heat-sealed is polyethylene, the propylene resin in the blend is a heat-sealable component for the surface of the packaging material, and the ethylene-based resin in the blend is a heat-seal material for the material to be heat-sealed. Acts as a sealing component.

(3) One layer of the multi-layer heat-sealable resin layer is a resin layer having a tight seal property with respect to at least one of the packaging material surface and the heat-sealed material, and the other layer is an easily peelable heat-seal. What is a resin layer. For the tight-sealing resin layer, the same kind of resin as the packaging material surface or the heat-sealed material is used, while as the easily peelable heat-sealing resin layer, the one described in the above item (1) is used. The tight-sealing resin layer may be provided in two layers by sandwiching the easily peelable heat-sealing resin layer.

(4) One layer of the multi-layer heat-sealable resin layer is a normal heat-sealable resin for the surface of the packaging material, and the other layer is a resin layer exhibiting low-temperature heat-sealability with respect to the heat-sealed material. some stuff. This type of multi-layer heat sealable resin layer
It is useful for imparting low temperature heat sealability.

As the low temperature heat-sealable resin layer used alone or in combination in the present invention, it is preferable to use a resin having a melting point at least 10 ° C. lower than the melting point of the original resin. The melting point of the resin layer is adjusted by selecting a polymerization method or a copolymerization method at the time of producing the resin, or by selecting the amount of the comonomer. Generally, the lower the density of the polymer, the lower the melting point,
Examples are PE) and low density polyethylene (LDPE). Further, a copolymer obtained by copolymerizing a certain amount of a comonomer with a homopolymer has a low melting point, and a propylene-ethylene copolymer (PPE) to homopolypropylene (PP) is an example of this. .. Even if the same copolymer is used, the melting point of the random copolymer is lower than that of the block copolymer, and the propylene-ethylene block (B) copolymer and the random (R) copolymer have Here is an example.

As the method for providing the heat-sealable resin layer on the substrate, generally, a method of co-extruding the heat-sealable resin at the time of forming the substrate film, a preformed film, a metal foil, paper, or a laminate of these is used. A method such as heat lamination or extrusion coating of a heat-sealable resin on a substrate such as a body is preferably applied. The heat-sealable resin layer preferably has a thickness of generally 1 to 50 μm, particularly 2 to 20 μm.

(Packaging material) Examples of the packaging material include a container body, a lid and the like, and these are any container forming materials known per se, for example, resin, metal, paper, glass, ceramic or a laminated body thereof. Can be formed from. The present invention is advantageous in that the heat-sealable resin layer can be applied to any packaging material regardless of the shape or material of the container. Examples of such a container include a two-piece or three-piece type with a flange or a bead. And a narrow or wide-mouthed glass or plastic bottle, a plastic cup container, a cup container of metal foil or a laminate thereof, a tray-shaped container, and the like. For the lid,
Molded lids such as flexible heat-seal lids and various caps can be used.

The container body particularly useful in the present invention is a cup container with a flange formed of a resin, a metal foil or a laminate of these, and the resin exemplified is the heat-sealable resin. Suitable examples of the resin cup-shaped container include ethylene vinyl alcohol copolymer, vinylidene chloride resin, gas barrier polyamide resin, gas barrier polyester resin and other gas barrier thermoplastic resin as an intermediate layer, and olefin resin. A sheet formed by molding a moisture-resistant thermoplastic resin as an inner or outer layer is subjected to plug assist molding in a molten state or in a solid phase.

Suitable examples of the cup-shaped container made of metal foil include a metal foil such as an aluminum foil, a steel foil, a tin foil, and an electrolytic chromic acid treated steel foil as an intermediate layer, and a plastic film such as an olefin resin or a polyester resin. It is formed by drawing a laminated body laminated as inner and outer layers with a combination of a punch and a die.

The lid is made of metal foil such as aluminum foil, tin foil, steel foil and tin foil, thermoplastic resin film such as biaxially oriented polyethylene terephthalate film, biaxially oriented nylon film and polycarbonate film, various papers or further. It is also possible to use these laminates or the like as a base material and laminate the above-mentioned heat-sealable resin layer as an inner surface material.

(Thermal Transfer Method) In the present invention, the laminate for transferring the heat-sealable resin layer is placed at a position where the heat-sealable resin layer and a portion of the wrapping material to be the heat-sealing surface face each other. Then, at least a part of the heat-sealable resin layer of the laminate is heat-transferred to a part of the packaging material that is to be the heat-sealing surface.

Thermal transfer is carried out by selectively heating the portion to which the heat-sealable resin layer is to be transferred, with the heat-sealable resin layer and the packaging material surface being in sufficient contact. For this heating, a heating / pressurizing mechanism by heat transfer such as a heat seal bar may be used, or high-frequency induction heating may be used when a metal material is included in the packaging material to be thermally transferred. .. The use of high frequency induction heating has the advantage that thermal transfer is performed in an extremely short time. Further, the heat transfer of the heat-sealable resin layer can be performed by irradiating ultrasonic vibration. The temperature of thermal transfer is a temperature equal to or higher than the melting point or softening point of the heat-sealable resin, and the melting point or softening point here means the unique melting point when the resin has a melting point, and does not have a definite melting point. In this case, it means the softening point. In the present invention, it is desirable that the heat-sealable resin exhibits cohesive failure at this heating temperature or the heat-sealable resin layer and the substrate exhibit interlaminar failure. The transfer of the heat seal resin layer may be completed by.

In the present invention, the heat transfer of the heat-sealable resin layer can be carried out to one or both of the packaging materials which are heat-sealed to each other, that is, to one or both of the container and the lid, but in general, to one of them. The desired purpose can be achieved by simply doing the following.

The heat transfer pattern of the heat sealable resin layer is not particularly limited. For example, in the case of a flanged container, it can be provided over the entire circumference of the flange or a part of the flange. Examples of the former are cases where low-temperature sealability is provided between the flange and the lid, cases where an easily peelable seal is provided, and examples of the latter are where an easily peelable seal is formed only at the opening start portion. If the outer peripheral side of the flange is an easily peelable seal and the inner peripheral side of the flange is a tight seal, the outer peripheral side and the inner peripheral side of the flange are the easily peelable seals, and the center of the flange is a tight seal. In such a case, the easily peelable seal portion and the tight seal portion may be alternately arranged in a circumferential shape on the flange. The tight seal is
By forming the heat-sealing surface of the container and lid with the same type of heat-sealable resin, the part where the easily peelable heat-sealable resin is lacking can be formed by heat-seal with the same type of resin. become.

In the heat transfer of the present invention, a heat sealing device known per se is used as it is or with some modifications, and a tape of a laminate for heat transfer of a heat sealable resin is intermittently or continuously supplied. By doing so, it can be easily performed. It goes without saying that the final packaging material can be heat-sealed in any manner using any heat-sealing device known per se.

[0039]

EXAMPLES The present invention will be specifically described in the following examples. Examples 1, 2, 3, 445 45 μm polypropylene layer and 5 μm propylene-
A coextruded film composed of two layers of a blend of an ethylene random copolymer and a linear low density polyethylene in a ratio of 3: 2 was prepared as a film for thermal transfer. The blend layer side of this film is placed on the heat seal flange surface of a multi-layer cup with polypropylene resin as the outer layer,
Heat fusion was performed under the condition of 180 ° C.-1 second. When the film was peeled off from this cup, the blend layer was cohesively broken, and a part of the blend layer was transferred to the flange surface in the same shape as the tip shape of the heat-sealing head used for transfer, with a uniform thickness. At this time, by using a heat-sealing head having a different tip shape, a container in which heat transfer is uniformly performed over the entire circumference of the heat-sealing flange (Fig. 2-
A), a container provided on the outer peripheral side and the inner peripheral side so as to exclude the central portion of the heat-sealing flange (FIG. 2-B), and a portion that is transferred only to the opening start portion and is not transferred in a bird's mouth shape. Each of the formed containers (Fig. 2-C) was created.

Of the containers prepared in this way, FIG.
Packaging material in which hot water at 70 ° C was placed in a cup that was heat-transferred to the pattern shown in Fig. 12, a biaxially stretched polyethylene terephthalate film of 12 µm, a soft aluminum foil of 7 µm, and a linear low-density polyethylene film of 50 µm were laminated as a heat seal resin Was used as a lid material and sealed under heat sealing conditions of 160 ° C. and 2 seconds. The sealed container was turned upside down and left for 1 week, but there was no leakage or reduction of the contents. Further, when the heat seal strength between the container and the lid was measured, it was 0.8 kgf per 15 mm width. Also, it could be easily opened by hand. [Example 1]

Similarly, hot water of 70 ° C. was placed in a cup which was subjected to thermal transfer in the pattern shown in FIG. 2A, and a biaxially stretched polyethylene terephthalate film of 12 μm and 7 μm were added.
Soft aluminum foil and heat seal resin 70μm
Using the packaging material obtained by laminating the propylene-ethylene block copolymer film of 1. as a lid material, it was sealed under heat sealing conditions of 180 ° C. and 2 seconds. Invert this sealed container 1
It was left for a week, but there was no leakage or reduction of the contents.
When the heat seal strength between the container and the lid was measured, it was 15 m.
It showed 1.4 kgf per m width. Also, it could be easily opened by hand. [Example 2] In the case of a cup not subjected to thermal transfer, it was necessary to raise the heat-sealing condition by about 20 ° C, and moreover, the heat-sealing strength was 4 kgf or more per 15 mm width, and opening by hand was difficult. ..

Hot water at 70 ° C. was placed in a cup which was subjected to thermal transfer in the pattern shown in FIG. 2-B, a 12 μm biaxially stretched polyethylene terephthalate film, a 15 μm biaxially stretched nylon film, a 20 μm soft aluminum foil, and
A 45 μm polypropylene layer, a 5 μm propylene-ethylene random copolymer, and a low density polyethylene were used in a ratio of 3: 1.
At a temperature of 210 ° C., using a packaging material laminated with a coextrusion film composed of two layers blended at a ratio of
It was sealed under a heat-sealing condition of −2 seconds and subjected to retort sterilization at 120 ° C. for 30 minutes. Invert this sealed container 1
After leaving for a week, the inner container did not leak or decrease.
Further, when the heat seal strength was measured, it was 2.5 kgf per 15 mm width, but it was easy to open by hand because the heat seal strength of the heat-transferred portion was low. [Embodiment 3] Although the heat seal strength of the cup not subjected to thermal transfer was the same as 2.5 kgf per 15 mm width, it was difficult to open it by hand.

Hot water at 70 ° C. was placed in a cup which was subjected to thermal transfer in the pattern shown in FIG. 2-C, and the cup was sealed with the lid material used in Example 3 under heat sealing conditions of 210 ° C. and 2 seconds.
Retort sterilization was performed at 0 ° C for 30 minutes. The sealed container was turned upside down and left for 1 week, but there was no leakage or reduction of the contents. Further, when the heat seal strength was measured, it was 2.5 kgf per 15 mm width as in Example 3, but due to the low heat seal strength of the heat-transferred portion and the fact that the transfer was devised in a bird's mouth shape, It was easier to start the opening than in Example 3. [Example 4]

As in Examples 1, 2, 3, and 4, by simply devising the shape of the heat seal head used at the time of transfer,
It became possible to apply the heat-sealable resin layer to a required portion with a constant thickness. In addition, heat sealing between different types of resins such as polypropylene-based cup containers and polyethylene-based lid materials has become possible. Further, it has become possible to impart low-temperature heat-sealing property and easy-opening property to the container.

Comparative Example 1 From the heat transfer film used in Example 1, cut pieces having the patterns shown in FIGS. 2-A, 2-B and 2-C were cut and heat-sealed in the cup container used in Example 1 as well. Tried to do. However, with this method, handling such as cutting out a section having a complicated shape from the film and accurately positioning the section at a predetermined position of the heat-sealing flange has been very difficult. In addition, a step is created at the boundary between where there is a section and where there is no section, and it is easy for air to be entrapped during filling and sealing, and when it becomes a bite seal such as water droplets, there is a sealing defect such as foaming at the heat seal part. It was seen.

In this way, the method of sticking a film has an undesired problem in handling and product quality. In addition, a special device is required to carry out this method with a device, which is not preferable in practice.

Example 5 An epoxy / phenolic coating film of 6 μm was formed on the outer surface,
1 μm of maleic acid modified polypropylene on the inner surface
A cup container with a flange for heat sealing was prepared by deep drawing a 75 μm steel foil on which an epoxy / phenolic coating film containing 0 part by weight was formed. A heat transfer film made of the co-extruded film used in Example 1 was placed on the heat-sealing flange surface of this container, and the flange side of the container was heated and fused by a high-frequency induction heating device.
When the base material is peeled off from this cup, the blend layer undergoes cohesive failure, and part of the blend layer is transferred to the same shape as the rubber pad between the high frequency seal head and the flange, with a uniform thickness all around the flange. It was

A drop lid made of low density polyethylene having the same shape as the outer shape of the heat-sealing flange of the container and having a grip portion for opening was formed by the compression molding method. The powder was placed in a cup container subjected to thermal transfer, and the lid side was heated by a high-frequency induction heating device to seal the flange side of the container. The sealed container was left for one week, but the contents did not absorb moisture. In addition, it could be easily opened by hand. The heat sealing between the cup container and the lid has been performed via the heat-sealable resin layer transferred to the container.

Example 6 A paint having a solid content of 10% by weight, in which a maleic acid-modified polypropylene was dissolved in a mixed solvent of MIBK and xylol, an acid component such as terephthalic acid, isophthalic acid, sebacic acid, maleic acid, and ethylene glycol, A coating material having a solid content of 30% by weight was prepared by dissolving a copolymerized polyester resin composed of a glycol component such as neopentyl glycol or propylene glycol in a mixed solvent of toluene and MEK. A coating material A was prepared by mixing the polypropylene coating material and the polyester coating material in a weight ratio of 9: 1 and the coating material A in a weight ratio of 1: 1. Next, using a poly (4-methylpentene-1) film of 50 μm as a base material, the coating material A was applied to one surface of the film using a roll coater,
It was dried in an oven at 150 ° C. The thickness of the coating film after drying was 6 μm. Further, the coating material B was applied in the same manner by using a roll coater and dried in an oven at 150 ° C. The total coating thickness after drying was 14 μm. The film thus double-coated was used as a film for thermal transfer, and the film was laminated on the heat-sealing flange surface of a crystallized polyethylene terephthalate cup at 200 ° C-
Heat fusion was performed under the condition of 1 second. When the substrate was peeled off from this cup, delamination occurred between the substrate film and the coating film, and the coating film was transferred to the same shape as the heat seal head with a uniform thickness over the entire circumference of the flange.

Put 70 ° C hot water in this cup,
Biaxially stretched polyethylene terephthalate film and 7μ
m soft aluminum foil and heat seal resin 70μ
Using a packaging material laminated with a polypropylene film of m, it was sealed under heat sealing conditions of 200 ° C. and 2 seconds.
The sealed container was turned upside down and left for 1 week, but there was no leakage or reduction of the contents. The heat seal strength was measured and found to be 1.8 kgf per 15 mm width.

As described above, according to the present invention, it becomes possible to apply the heat-sealable resin layer to only a necessary portion with a constant thickness without directly contacting the solvent with the solvent. In addition, heat sealing between different resins such as a polyethylene terephthalate type cup and a polypropylene type packaging material has become possible.

Comparative Example 2 Attempts were made to directly apply the paint A and the paint B used in Example 6 to the cup container used in Example 6 as well. First, the paint B was applied to the heat-sealing flange surface using a brush, but it is difficult to apply the paint uniformly only to a predetermined position, and the paint drips inside the container where the application amount is large. Oops. When this was dried in an oven at 150 ° C., the coating film thickness became non-uniform, and foaming was observed in areas where the coating amount was large. Next, the paint B was applied so that the heat-sealing flange surface of the container was facing down, and only the heat-sealing surface was immersed in the paint surface, and the container was dried in an oven at 150 ° C. while holding the container upside down. In this case, the paint was applied to almost the entire surface of the heat-sealing flange, and the amount of application varied widely. In addition, the coating film in the central portion of the flange became thick and foaming was observed.

Applying the paint directly to the heat-sealing flange portion of the container in this manner makes it difficult to secure a constant application area and application amount, and to apply the paint to parts other than necessary parts such as the inside of the container. It is not preferable from the standpoints of contamination by water and migration of solvent. Further, it is not practically preferable to apply a certain pattern because a special device is required.

[0054]

According to the present invention, the heat-sealable resin layer is composed of the substrate and the heat-sealable resin layer and has cohesive failure property at the time of heating or peeling after heating, or the heat-sealable resin layer A laminated body having a substrate and interlaminar destructive properties is superposed on a packaging material in such a positional relationship that the heat-sealable resin layer and a portion of the packaging material that should be the heat-sealing surface face each other, and the laminated body is heat-sealed. By heat-transferring at least a part of the functional resin layer to a part to be the heat-sealing surface of the packaging material, a desired shape of the heat-sealing material is applied to any selected part of the part to be heat-sealed of the container or the lid, The area and the thickness can be accurately applied, and in particular, properties such as easy peeling property, low temperature sealing property, and heat sealing property with different kinds of resin which the target packaging material originally cannot have can be imparted.

In addition, heat-sealing resin or resin composition having various functions can be applied to a packaging material such as a container or a lid with excellent workability without limitation on film forming property to a film or solubility in a solvent. It can be applied to any heat-sealed surface.

Further, the heat-sealing surface of the packaging material is a portion to which the other material to be heat-sealed is originally applied to this packaging material and a heating mechanism for heat-sealing such as a heat-seal bar comes into contact with or acts on. Therefore, the operation for heat sealing, the device, the control means, etc. can be similarly applied to the heat transfer of the heat sealing resin layer to the packaging material,
It offers the advantage of being reliable and easy to operate.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining the principle of the present invention.

FIG. 2 is a diagram showing an example of a thermal transfer pattern of a heat-sealable resin layer.

[Explanation of Symbols] 1 is a cup-shaped container, 2 is a flange, a substrate, 4 is a heat-sealable resin layer, 5 is a laminate, and 6 is a hot plate.

Claims (5)

[Claims] 1. A heat-sealable resin layer comprising a substrate and a heat-sealable resin layer and having cohesive failure during heating or peeling after heating, or between the heat-sealable resin layer and the substrate at interlaminar failure. Is laminated on the packaging material in a positional relationship in which the heat-sealing resin layer and a portion of the packaging material to be the heat-sealing surface face each other, and at least one of the heat-sealing resin layers of the laminate is laminated. A method for applying a heat-sealable resin, characterized in that the part is thermally transferred to a part to be the heat-sealing surface of the packaging material. 2. The application method according to claim 1, wherein the heat-sealable resin layer comprises a blend of two or more resins. 3. One component of the blend is a resin component exhibiting heat sealability to at least one of the packaging material surface and the heat-sealed material, and the other component of the blend is a resin component imparting easy peeling property. Claim 2 characterized by the above.
Application method described. 4. One of the components of the blend is a resin component having heat sealability with respect to the packaging material surface, and the other component of the blend is a resin component having heat sealability with respect to the heat-sealed material. The application method according to claim 2, wherein the application method is present. 5. The application method according to claim 1, wherein the heat-sealable resin layer comprises a copolymer containing a monomer component common to the resin constituting at least one of the packaging material surface and the heat-sealed material.