JP6858489B2 - In-mold label continuum and its manufacturing method - Google Patents

Description

The present invention relates to an in-mold label continuum in which a plurality of in-mold labels are attached side by side on a release sheet, and a method for producing the same.

The in-mold label is a label that is integrally incorporated in the resin molded body. As for the in-mold label, it is not necessary to separately attach the label to the container, and when the in-mold label is used, the feeling of unity with the resin is excellent, so that an in-mold molded product that is preferable in appearance can be obtained.
The in-mold label having a heat-sensitive adhesive has a single-wafer shape, and is stored and transported in a state of a laminate in which a plurality of the in-mold labels are stacked in the thickness direction (Patent Document 1). When the in-mold label is used (during molding), the in-mold label is taken out one by one from the stacked laminate.

However, since the heat-sensitive adhesive is activated by heat to generate adhesiveness, the in-mold labels stacked on the top and bottom are pseudo-adhered to each other during storage of the laminate, and one by one at the time of use. It may not be possible to take it out. In particular, as described in Patent Document 1, such a situation is likely to occur in an in-mold label using a heat-sensitive adhesive that is activated at 60 ° C to 70 ° C.
Further, the use of the in-mold label has an advantage that an in-mold molded product that is preferable in terms of appearance can be obtained, but the in-mold label may become cloudy and the appearance of the in-mold molded product may be deteriorated. In particular, when the in-mold label becomes cloudy, the transparent portion of the in-mold label loses a sense of unity with the resin molded body, and improvement thereof is required.

Japanese Unexamined Patent Publication No. 2014-071369

The purpose of the present invention can be taken out one by one reliably in-mold label in use, further, in-mold label strip and a manufacturing method thereof hardly-mold label with white turbidity upon the Lee Nmorudo moldings Is to provide.

The in-mold label continuum of the present invention has an in-mold label having a label base material, an adhesive layer provided on the back surface of the label base material and composed of a heat-sensitive adhesive, and a transparent portion, and a long strip shape. A plurality of the in-mold labels are attached side by side with the back surface of the adhesive layer abutting on the release surface of the release sheet, and the adhesive is adhered to the release surface. The adhesive strength of the layer is 0.05 N / 15 mm to 0.7 N / 15 mm, and the ten-point average roughness Rz of the back surface of the adhesive layer and the ten-point average roughness Rz of the release surface of the release sheet are , Each is 3 μm or less .

In the preferred in-mold label continuum of the present invention, the heat-sensitive adhesive contains an olefin-based elastomer .
In the preferred in-mold label continuum of the present invention, the heat-sensitive adhesive is a low-temperature active type heat-sensitive adhesive.

According to another aspect of the present invention, there is provided a method for producing an in-mold label continuum.
In this manufacturing method, the 10-point average roughness Rz of the release surface was melted between the release surface of the long strip-shaped release sheet and the original fabric of the long strip-shaped label base material. A step of obtaining a laminate in which a release sheet, an adhesive layer made of a heat-sensitive adhesive, and a label base material raw material are laminated in this order by interposing a heat-sensitive adhesive, and the label base material raw material is cut in the thickness direction. This includes a step of partitioning the label base material raw fabric into a plurality of in-mold labels arranged in the longitudinal direction and having a transparent portion.

In the preferred method for producing an in-mold label continuum of the present invention, the heat-sensitive adhesive contains an olefin-based elastomer .
In the preferred method for producing an in-mold label continuum of the present invention, the heat-sensitive adhesive is a low-temperature active type heat-sensitive adhesive.

The in-mold label continuum of the present invention can reliably take out the in-mold labels one by one.
Further, the in-mold label provided in the in-mold label continuum of the present invention is less likely to become cloudy when incorporated into an in-mold molded product, and by using such an in-mold label, an in-mold molded product having a good appearance is obtained. Can be produced.
Further, according to the method for producing an in-mold label continuum of the present invention, the in-mold label continuum can be easily produced.

A plan view of the in-mold label continuum of one embodiment as viewed from the surface side. Side view of the in-mold label continuum. An enlarged cross-sectional view taken along the line III-III of FIG. FIG. 5 is an enlarged cross-sectional view taken along the line IV-IV of FIG. The plan view which looked at the in-mold label continuum of another embodiment from the surface side. The schematic diagram which shows typically each process in the manufacturing method of an in-mold label continuum. The perspective view which shows the state which took out the in-mold label from the in-mold label continuum.

Hereinafter, the present invention will be specifically described with reference to the drawings.
In this specification, the "front surface" in the description of the in-mold label and the in-mold label continuum refers to the surface that is the front surface side of the molded product when it is an in-mold molded product, and the "back surface" is the surface thereof. Refers to the opposite surface (the surface that is on the resin molded body side when made into an in-mold molded product).
The numerical range represented by "~" means a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value.
Please note that the dimensions, scales and shapes of the parts and members shown in each figure may differ from the actual ones.

[First Embodiment]
In FIGS. 1 to 4, the in-mold label continuum 1 includes a long strip-shaped release sheet 2 and a plurality of in-mold labels 3 attached side by side on the release surface 2a of the release sheet 2. Has.
The in-mold label 3 has a label base material 4 and an adhesive layer 5 composed of a heat-sensitive adhesive, and the adhesive layer 5 is provided on the back surface of the label base material 4. The back surface 5a of the adhesive layer 5 is brought into contact with the release surface 2a of the release sheet 2, and a plurality of in-mold labels 3 are independently attached to the release surface 2a of the release sheet 2.

In the in-mold label continuum 1, the back surface 5a of the adhesive layer 5 is weakly adhered to the release surface 2a of the release sheet 2, so that the in-mold labels 3 are attached side by side on the release sheet 2.
The adhesive strength of the adhesive layer 5 of the in-mold label 3 to the release surface 2a of the release sheet 2 is such that the in-mold label 3 does not peel off even when the in-mold label continuum 1 is wound in a roll shape. The strength is not particularly limited as long as the strength is such that the in-mold label 3 can be easily peeled off when necessary. For example, the adhesive strength of the adhesive layer 5 to the release sheet 2 is 0.05 N / 15 mm to 0.7 N / 15 mm, preferably 0.1 N / 15 mm to 0.5 N / 15 mm. The adhesive strength refers to a value measured by a method similar to JIS Z 0237 180 degree peeling. Specifically, the adhesive strength is such that the in-mold label attached to the release surface of the release sheet via the adhesive layer is cut out in a length × width = 100 mm × 15 mm to prepare a sample, and the sample is prepared. The maximum strength when the in-mold label is peeled off at a temperature of 23 ± 2 ° C., a humidity of 50 ± 5% RH, and a speed of 300 mm / min.
In the in-mold label 3, the adhesive strength between the back surface of the label base material 4 and the front surface of the adhesive layer 5 is extremely high, and it is difficult to separate the label base material 4 and the adhesive layer 5.

As shown in FIG. 2, the in-mold label continuum 1 is usually wound into a roll and stored / transported. In this case, the in-mold label continuum 1 may be wound with the in-mold label 3 on the outside, or may be wound with the in-mold label 3 on the inside. In the illustrated example, the in-mold label continuum 1 is wound around the core material 91 with the in-mold label 3 on the outside.

The release sheet 2 has a long strip shape. Here, in the present specification, the long strip shape is a substantially rectangular shape whose length in one direction is 10 times or more the length in the direction orthogonal to the length, preferably 30 times or more, and more preferably 100. More than double.
The release sheet 2 is made of a sheet having a surface having a small wettability.
In the illustrated example, the release sheet 2 has a base sheet 21 and a release layer 22 laminated on the entire surface of the base sheet 21. The release layer 22 is formed in a solid shape on the entire surface of the base sheet 21. In the present specification, when a certain layer is solid, it means that the materials constituting the layer extend in the plane direction to form one continuous layer. The surface of the release layer 22 is the release surface 2a of the release sheet 2.

The release layer 22 can be typically formed by a method such as applying a release agent containing a silicone resin or the like to the surface of the base sheet 21.
The base sheet 21 is not particularly limited, and is, for example, a synthetic resin sheet such as polyester, polystyrene, vinyl chloride resin; a laminated resin sheet in which a plurality of different or similar resin layers are laminated; synthetic paper; plain paper, high-quality paper, etc. Paper; Examples thereof include a laminated sheet in which two or more types of sheets selected from these are laminated. The base sheet 21 is preferably a synthetic resin sheet or a laminated resin sheet. By using the synthetic resin sheet or the laminated resin sheet, the adhesive layer 5 in contact with the release sheet 2 becomes a mirror surface state, and it is possible to prevent the in-mold label 3 from becoming cloudy due to the unevenness of the adhesive layer 5.
The base sheet 21 may have enough strength to be conveyed by the conveying line provided in the molding apparatus, and its thickness is not particularly limited, and is, for example, 30 μm to 300 μm. The thickness of the release layer 22 is not particularly limited, and is, for example, about 0.1 μm to 3 μm. The base sheet 21 may be transparent or opaque.
When a base sheet 21 having a low wettability (a base sheet 21 having an excellent mold release property) is used, the release layer 22 may be omitted. In this case, the surface of the base sheet 21 becomes the release surface 2a of the release sheet 2.

A plurality of in-mold labels 3 are attached side by side at desired intervals in the longitudinal direction of the long strip-shaped release sheet 2 or with the edges in contact with each other. In the illustrated example, the in-mold labels 3 adjacent to each other in the longitudinal direction are arranged at desired intervals. Since the in-mold labels 3 are arranged at intervals, the individual in-mold labels 3 can be independently peeled off when the release sheet 2 is inverted at the peel portion described later.
Note that FIG. 1 illustrates an in-mold label continuum 1 in which the in-mold labels 3 are arranged in a row in the lateral direction of the release sheet 2, but as shown in FIG. 5, for example, the in-mold labels 1 are in-molded. The labels 3 may be arranged in two rows in the lateral direction, and may be arranged in three or more rows in the lateral direction, although not particularly shown.

The plan-view shape of the in-mold label 3 is not particularly limited, and is appropriately designed in consideration of the shape and design of the in-mold molded product to be obtained. For example, the plan view shape of the in-mold label 3 (label base material 4) is a substantially rectangular shape in a plan view as shown in FIG. Examples include a circular shape and a substantially elliptical shape. In the present invention, the "abbreviation" of the plan view shape means a shape permitted in the technical field to which the present invention belongs. The "abbreviation" of a substantially polygonal shape such as a substantially rectangular shape or a substantially triangular shape in a plan view is, for example, a shape in which corners are chamfered, a shape in which a part of a side is slightly bulged or recessed, or a shape in which a side is slightly curved. Includes the shape of the shape. Further, the "abbreviation" of the substantially circular shape and the substantially elliptical shape in the plan view includes, for example, a shape in which a part of the circumference is slightly bulged or recessed, a shape in which a part of the circumference is slightly straight or diagonal, and the like. Is done.

The in-mold label 3 has a label base material 4 and an adhesive layer 5. Further, the in-mold label 3 may have a print layer 61 and, if necessary, any suitable functional layer (not shown) such as an anchor coat layer and a protective layer. These functional layers are preferably transparent. The thickness of the functional layer such as the protective layer is not particularly limited, but is, for example, 1 μm to 10 μm.
As the label base material 4, a flexible sheet that does not melt due to heat during the production of the in-mold molded product is used. The label base material 4 is not particularly limited, and a sheet selected from synthetic resin sheets, paper, synthetic papers, foamed resin sheets, non-woven fabrics, and the like can be used. Further, a sheet provided with a barrier layer (gas barrier and / or a light-shielding layer) on a sheet such as the synthetic resin sheet, a sheet provided with other functional layers such as thin-film deposition, heat insulation, and antibacterial, and these sheets are 2 A laminated body in which more than seeds are laminated may be used. The synthetic resin sheet and foamed resin sheet are made of polypropylene, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, ethylene-cyclic olefin copolymer and other polyolefin-based materials; polyethylene terephthalate, polylactic acid and other polyester-based materials. Vinyl halides such as polyvinyl chloride; Polypropylenes such as 6,6 nylons; One type of thermoplastic resins such as polystyrenes and polystyrenes such as ABS, and mixtures thereof. As the synthetic resin sheet, a biaxially stretched polyethylene terephthalate resin sheet is particularly preferable.
Further, the label base material 4 may have a relatively large heat shrinkage property, but a label base material 4 having a slight heat shrinkage property or a material having substantially no heat shrinkage property is preferable.

The label base material 4 may be transparent or opaque. A transparent label base material 4 is preferable because when an in-mold molded product is formed, the resin molded body can be seen through the label and a sense of unity with the resin molded body can be obtained. Examples of such a transparent label base material 4 include the synthetic resin sheet as described above.
In the present specification, transparent (colorless transparent or colored transparent) means a case where the total light transmittance is 70% or more, preferably 80% or more, and more preferably 90% or more. However, the total light transmittance refers to a value measured by a measurement method based on JIS K 7361 (test method for total light transmittance of plastic-transparent material). In addition, opacity means transparency to the extent that the design displayed on the back surface side of the label base material 4 cannot be recognized from the front surface side.
The thickness of the label base material 4 is not particularly limited, but is, for example, 10 μm to 100 μm, preferably 15 μm to 60 μm, and more preferably 20 μm to 50 μm. The in-mold label 3 made of the label base material 4 having such a thickness is generally thin and difficult to handle, but in the present invention, since the in-mold label 3 is attached to the release sheet 2, the label base material is attached. Problems such as curl due to the thickness of 4 and the like do not occur.

The print layer 61 may be transparent or opaque. The opaque print layer is formed using a known coloring ink, and the transparent printing layer is formed using an ink that does not contain a known coloring agent. The opaque print layer may be a print layer representing a desired design, or may be a patternless one-color print layer. Further, the transparent or opaque print layer may be one layer or two or more layers may be provided in layers.
Further, the printing layer 61 is provided on the front surface or the back surface of the label base material 4, or is provided on the front surface and the back surface of the label base material 4. Preferably, the print layer 61 is provided on the surface of the label base material 4 as shown in the illustrated example.
The print layer 61 may be provided on the entire front surface (or back surface) of the label base material 4, or may be provided in a partial region thereof. In the illustrated example, the opaque print layer 61 is provided except for the peripheral edge portion of the transparent label base material 4, and therefore, the peripheral edge portion of the label base material 4 is a region having no print layer 61. In FIG. 1, innumerable dots are added to the range where the opaque print layer 61 is provided for convenience.
The thickness of the print layer 61 is not particularly limited, but is, for example, 1 μm to 10 μm.

When the print layer 61 is provided on the surface of the label base material 4, a transparent protective layer (not shown) may be provided at least on the surface of the print layer 61 in order to protect the print layer 61. When the print layer 61 is provided in a part of the surface of the label base material 4, the protective layer is only the surface of the print layer 61, or the print layer of the surface of the print layer 61 and the label base material 4. It is provided on the surface of the region where 61 is not provided. The protective layer is formed using a known varnish or the like. A transparent synthetic resin sheet may be separately attached as the protective layer. In this case, from the viewpoint of transparency, the synthetic resin sheet is preferably a polyethylene terephthalate resin sheet.

The adhesive layer 5 is composed of a heat-sensitive adhesive, preferably a low-temperature active type heat-sensitive adhesive. In the low temperature active type heat-sensitive adhesive, the activation temperature can be appropriately selected, but is preferably 60 ° C. to 110 ° C., more preferably 60 ° C. to 90 ° C., and further preferably 60 ° C. to 70 ° C. Is. The in-mold label 3 having an adhesive layer 5 composed of a heat-sensitive adhesive that is activated at such a temperature can be suitably used for producing an in-mold molded product by various molding methods. Among them, the in-mold label 3 having an adhesive layer 5 composed of a heat-sensitive adhesive that is activated at 60 ° C. to 70 ° C. can be particularly suitably used for producing an in-mold molded product by an injection blow molding method. The in-mold label 3 on which the adhesive layer 5 is formed using such a low-temperature active heat-sensitive adhesive is suitable for producing an in-mold molded product made of polyethylene terephthalate having a low molding temperature and a relatively weak molding pressure. An in-mold molded product that can be used and has high transparency can be obtained.
The adhesive layer 5 is provided in a solid shape on the entire back surface of the label base material 4. The adhesive layer 5 may be laminated on the back surface of the label base material 4 with a difference in thickness, but preferably, the adhesive layer 5 has a substantially uniform thickness in the surface direction of the label base material 4. When the adhesive layer 5 has a difference in thickness, the thickness of the adhesive layer 5 (adhesive layer peripheral edge) corresponding to the peripheral edge of the back surface of the label base material 4 corresponds to the adhesive layer 5 (adhesive) other than the peripheral edge. The thickness is smaller than the thickness of the central portion of the layer), and the thickness gradually increases from the peripheral edge of the adhesive layer toward the central portion of the adhesive layer.
The thickness of the adhesive layer 5 is not particularly limited, but is, for example, 5 μm to 30 μm, preferably 10 μm to 20 μm.
A known anchor coat layer (not shown) is provided on the back surface of the label base material 4 in order to firmly bond the back surface of the label base material 4 and the adhesive layer 5, and an adhesive layer is provided on the back surface of the anchor coat layer. 5 may be provided.

Sensitive Netsuse' Chakuzai shows a glue that is applied by heating and melting by a hot-melt coater or extrusion laminator, after coating, the adhesive I'll be heated and do not exhibit adhesiveness at room temperature It is an adhesive.
The heat-sensitive adhesive is preferably transparent.

As the feeling Netsuse' Chakuzai, for example, ethylene - vinyl acetate copolymer (EVA), ethylene - acrylic ester copolymer, ethylene - methacrylic acid ester copolymer, a thermoplastic elastomer (synthetic rubber, ethylene - Adhesive-imparting agents such as petroleum-based, terpen-based, terpenphenol-based, and chroman-inden-based adhesives, and additives such as wax and lubricant are mixed with base resins such as α-olefin and other olefin-based and urethane-based and other thermoplastic elastomers. The ones that have been made are listed. Examples of the wax include higher fatty acid-based waxes and polyethylene-based waxes, and examples of the lubricant include amide-based waxes. The base resin and the like can be used alone or in combination of two or more. Preferably, the base resin of the heat-sensitive adhesive contains an ethylene-based copolymer and an olefin-based elastomer, and more preferably contains an ethylene-vinyl acetate copolymer and an olefin-based elastomer. Such thermal adhesives are activated at relatively low temperatures. When the base resin contains an ethylene-based copolymer (preferably an ethylene-vinyl acetate copolymer) and an olefin-based elastomer, the content ratio thereof is not particularly limited. The content of the ethylene-based copolymer in the heat-sensitive adhesive is, for example, 20% by mass to 60% by mass, preferably 25% by mass to 55% by mass, and the content of the olefin-based elastomer is, for example, It is 10% by mass to 50% by mass, preferably 15% by mass to 45% by mass, and the content of the tackifier is, for example, 1% by mass to 40% by mass, preferably 5% by mass. ~ 35% by mass. Among them, a heat-sensitive adhesive containing an ethylene-based copolymer (preferably an ethylene-vinyl acetate copolymer) and an olefin-based elastomer as a base resin and having a melting point of about 80 ° C. is preferable.

The back surface 5a of the adhesive layer 5 and the release surface 2a of the release sheet 2 are preferably as smooth as possible. Since the back surface 5a of the adhesive layer 5 is smooth, it is possible to prevent the in-mold label 3 incorporated in the in-mold molded product from becoming cloudy.
Preferably, the ten-point average roughness Rz of the back surface 5a of the adhesive layer 5 is 3 μm or less, more preferably 2 μm or less, and further preferably 1 μm or less. By using the in-mold label 3 having such an adhesive layer 5, it is possible to obtain an in-mold molded product that is less likely to become cloudy and is preferable in appearance. The lower limit of the ten-point average roughness Rz of the back surface 5a of the adhesive layer 5 is theoretically zero, but a realistic numerical value exceeds zero.
In the present specification, the ten-point average roughness Rz is a value measured by a method according to JIS B 0601-1994. Specifically, for example, using a surface roughness measuring machine (trade name "Handy Surf E-35A" manufactured by Tokyo Seimitsu Co., Ltd.), the surface of the sample is subjected to a surface scanning method based on JIS B 0601-1994. The ten-point average roughness Rz is measured by measuring an arbitrary point.

The in-mold label 3 has a transparent portion 3b (transparent portion). The transparent portion 3b is composed of a portion of the transparent label base material 4 whose transparency is not substantially impaired. The transparent portion 3b is, for example, (1) a region of the transparent label base material 4 provided with the transparent adhesive layer 5 and not provided with the opaque printing layer 61 (in the illustrated example, the peripheral edge of the label base material 4). The portion is a transparent portion 3b), (2) a region of the transparent label base material 4 provided with the transparent adhesive layer 5 and not provided with other opaque layers, and the like.
The transparent portion 3b of the in-mold label 3 may be either colorless and transparent or colored and transparent, and is preferably colorless and transparent. The transparent portion 3b of the in-mold label 3 refers to, for example, a case where the total light transmittance is 70% or more, preferably 80% or more, and more preferably 90% or more.

[Manufacturing method of in-mold label continuum]
The in-mold label continuum 1 can be manufactured, for example, as follows. However, the in-mold label continuum 1 of the present invention is not limited to that obtained by the following manufacturing method.
In the method for producing the in-mold label continuum 1 of the present invention, a melted heat-sensitive adhesive is interposed between a long strip-shaped release sheet and a long strip-shaped label base material raw material for mold release. A step of obtaining a laminated body in which the sheet 2, the adhesive layer 5 made of a heat-sensitive adhesive, and the label base material raw material are laminated in this order. By cutting the label base material raw material in the thickness direction, the label base material raw material is cut. Has a step of partitioning the label into a plurality of in-mold labels in the longitudinal direction.
Specifically, the method for producing the in-mold label continuum 1 includes a step of preparing a long strip-shaped release sheet and a label base material raw material, a step of obtaining the laminate, and a step of partitioning into the plurality of in-mold labels. A step of removing an unnecessary portion of the label base material raw material is provided in this order.
Each of these steps may be carried out in a series on one production line, or one or more steps selected from the above steps may be carried out on one line, and the remaining steps may be carried out on the other one or more. You may go on two or more lines. In addition, one performer may perform all of the steps, or one performer may perform one or more steps selected from the steps, and the remaining steps may be performed by another. May be done by a person.

<Preparation process>
Prepare a long strip-shaped release sheet 2 and a long strip-shaped label base material raw material.
The long strip-shaped release sheet 2 may be prepared as described above, but the release sheet 2 having a ten-point average roughness Rz of the release surface 2a of 3 μm or less can be prepared. preferable. By using such a release sheet 2, the in-mold label 3 having the adhesive layer 5 having excellent back surface smoothness as described above can be easily formed.
The release sheet 2 having a ten-point average roughness Rz of the release surface 2a of 3 μm or less has a release layer having a thickness of 0.1 μm to 3 μm on the surface of the long strip-shaped base sheet 21 using a gravure coater or the like. It can be obtained by applying a release agent so that it can be obtained.

As the material of the long strip-shaped label base material raw material, those as exemplified in the above label base material 4 can be used. It is preferable that the length of the long strip-shaped label base material in the lateral direction is the same as the length of the release sheet 2 in the lateral direction.
The long strip-shaped label base material is provided with a printing layer 61, a protective layer, and the like representing the above design at desired intervals in the longitudinal direction thereof. Further, if necessary, an anchor coat layer is provided in a solid shape on the back surface of the raw material of the label base material.
The long strip-shaped release sheet and the long strip-shaped label base material raw fabric are stored and transported in a rolled state, respectively.

<Laminating process>
As shown in FIG. 6, the long strip-shaped release sheet 2 and the long strip-shaped label base material raw fabric 4A are independently conveyed to one side in the longitudinal direction. The transport direction is indicated by an arrow.
During this transfer, the mold release sheet 2 and the label base material raw fabric 4A are interposed between the release surface of the release sheet 2 and the back surface of the label base material raw fabric 4A while the melted thermal adhesive 5A is interposed. Is crimped. Specifically, as shown in FIG. 6, the release surface of the release sheet 2 and the back surface of the label base material original fabric 4A are passed through a crimping roll 83 composed of a main roll 81 and a sub roll 82 so as to face each other. .. Immediately before passing the release sheet 2 and the label base material raw fabric 4A between the main roll 81 and the secondary roll 82, the release sheet 2 was melted on the release surface of the release sheet 2 or the back surface of the label base material raw fabric 4A. Place the thermal adhesive 5A. The heat-sensitive adhesive 5A is heated and melted by an extruder (not shown) and extruded from the die 84 in the form of a film over the entire lateral direction of the release sheet 2 (so-called sand laminate). The heating temperature of the heat-sensitive adhesive is equal to or higher than the melting point of the heat-sensitive adhesive (for example, 200 ° C. to 250 ° C.), and is appropriately set according to the type of the heat-sensitive adhesive.

At least one of the main roll 81 and the sub roll 82 is provided with a cooling device (not shown). While passing through the pressure-sensitive adhesive roll 83, the melted heat-sensitive adhesive 5A is cooled, and an adhesive layer made of the heat-sensitive adhesive is formed between the release surface of the release sheet 2 and the back surface of the label base material raw fabric 4A. It is formed. In this way, a long strip-shaped laminated body 7A laminated in the order of the release sheet / adhesive layer / label base material raw fabric is obtained.
After obtaining the laminated body 7A, it may be wound up in a roll shape once, and the laminated body 7A may be pulled out from the roll to perform the next cutting step, or after the laminated body 7A is obtained, the next step is continued as it is. The cutting step of the above may be performed.

<Cutting process>
By cutting the label base material raw fabric 4A in the thickness direction of the laminated body 7A, the in-plane of the label base material raw fabric 4A is divided into a plurality of in-mold labels 3 arranged in the longitudinal direction thereof. A plurality of in-mold labels 3 can be formed by cutting the in-plane of the label base material raw fabric 4A so as to match the plan-view shape of the in-mold label 3. The cutting can be performed using, for example, a die roll 85 or the like.
On the condition that the release sheet 2 is not cut, only the label base material raw material 4A may be cut, or the label base material raw material 4A may be cut including the adhesive layer. Since the adhesive layer itself is brittle, unnecessary portions described later can be removed even when only the label base material raw fabric 4A is cut.

<Removal process>
The unnecessary portion 71A of the label base material raw fabric 4A, excluding the in-mold label 3 partitioned in the cutting step, is removed from the release sheet 2 and recovered. At this time, the unnecessary portion 71A is peeled off between the adhesive layer adhered to the back surface of the unnecessary portion 71A and the release surface of the release sheet 2, and the unnecessary portion 71A with the adhesive layer is released from the release sheet. Removed from 2.
In this way, as shown in FIGS. 1 to 4, an in-mold label continuum 1 in which a plurality of in-mold labels 3 are attached to the release sheet 2 at desired intervals can be obtained. The obtained in-mold label continuum 1 is wound into a roll.
By setting the adhesive strength of the adhesive layer 5 of the in-mold label 3 to the release surface 2a of the release sheet 2 within the above range (0.05N / 15mm to 0.7N / 15mm), the unnecessary portion 71A It is possible to prevent the in-mold label 3 from being peeled off from the release sheet 2 when removing the in-mold label 3, and it is possible to prevent the in-mold label 3 from being inadvertently peeled off when the in-mold label 3 is wound into a roll.

According to the above manufacturing method, the in-mold label continuum 1 can be easily manufactured.
In particular, using the release sheet 2 having a ten-point average roughness Rz of 3 μm or less on the release surface 2a, the melted heat-sensitive adhesive 5A is applied to the release surface 2a of the release sheet 2 and the back surface of the label base material original fabric 4A. The surface shape of the release surface 2a is transferred to the back surface 5a of the adhesive layer 5 by passing the release sheet 2 and the label base material raw material 4A through the pressure-bonding roll 83 and applying pressure. That is, when the release surface 2a of the release sheet 2 is a mirror surface, an adhesive layer 5 having a mirror surface on the back surface 5a is formed, and the release surface 2a of the release sheet 2 has fine irregularities. Is formed with an adhesive layer 5 in which the back surface 8a has a convex corresponding to the concave of the release surface 2a and a concave corresponding to the convex of the release surface 2a.
Therefore, the back surface 5a of the adhesive layer of the in-mold label 3 is formed with irregularities due to the fine irregularities of the release surface 2a of the release sheet 2.
Therefore, by using the release sheet 2 in which the ten-point average roughness Rz of the release surface 2a is 3 μm or less, the adhesive layer 5 having excellent back surface smoothness (for example, the ten-point average roughness Rz of the back surface 5a can be obtained. The in-mold label 3 having the adhesive layer 5) having an adhesive layer of 3 μm or less can be easily formed.
Further, since the back surface 5a of the adhesive layer 5 is attached in contact with the release sheet 2 in a state of excellent back surface smoothness, the back surface 5a of the adhesive layer 5 is protected during storage and transportation of the in-mold label 3. Will be done. Therefore, the in-mold label 3 is easy to handle.

[Use of in-mold label continuum]
The in-mold label continuum 1 is used when manufacturing an in-mold molded product. An in-mold molded product is obtained by pulling out the in-mold label continuum 1 wound in a roll shape, peeling the in-mold label 3 from the in-mold label continuum 1, and in-mold molding.
In the in-mold label continuum 1 of the present invention, since the in-mold label 3 is attached to the release sheet 2, the in-mold labels 3 do not block each other. Further, since the plurality of in-mold labels 3 are arranged in the longitudinal direction of the release sheet 2 and are detachably attached to the release sheet 2, the in-mold label 3 is removed from the in-mold label continuum 1 at the time of use. It can be easily taken out one by one. In particular, the adhesive strength of the adhesive layer 5 of the in-mold label 3 to the release surface 2a of the release sheet 2 is within the above range (0.05N / 15 mm to 0.7N / 15 mm), so that the release sheet 2 The in-mold label 3 can be reliably peeled off from the surface.

The in-mold molded product (not shown) has a resin molded body molded by in-mold molding and an in-mold label 3 incorporated on the surface of the resin molded body by in-mold molding.
The resin material constituting the resin molded product is not particularly limited as long as it is a thermoplastic resin, and known materials can be appropriately used. The resin material (resin molded product) may be transparent or opaque, but is preferably transparent.
Examples of the resin material include olefin-based materials such as high-density polyethylene and polypropylene, polyester-based materials, polystyrene-based materials, polyvinyl chloride-based materials, and polycarbonate-based materials. The resin material is usually non-foaming, but may be foamed if necessary. Of these, polyesters such as polyethylene terephthalate are preferable because of their excellent transparency.
The wall thickness of the resin molded product is not particularly limited, but is preferably 0.3 mm or more, more preferably 0.5 mm or more, in order to obtain a molded product having a certain degree of rigidity.

The use of the in-mold molded product of the present invention is not particularly limited, and various containers (bottle-shaped container, box-shaped container, cup-shaped container, etc.) for storing beverages, foods, sanitary products, chemicals, supplements, cosmetics, toys, etc. ) Is a typical application, but it can also be used for the lid of a container. Further, the in-mold molded product of the present invention can also be applied to applications other than those related to containers, for example, device parts and the like.
The shape of the in-mold molded product is also not particularly limited, and is formed into an appropriate shape according to the application.
The fixing position of the in-mold label 3 with respect to the resin molded body is not particularly limited, and the in-mold label 3 can be incorporated at an arbitrary position such as the body or bottom of the resin molded body. When the in-mold molded product is used as a container, it is preferable to incorporate the in-mold label 3 in the body of the resin molded product.

In producing the in-mold molded product, as shown in FIG. 7, the in-mold label continuum 1 is fed in the longitudinal direction using a transport device, and the release sheet 2 is inverted at the peel portion 86 in the middle of the feed. , The in-mold label 3 is peeled off from the release surface 2a of the release sheet 2. By feeding the continuum 1 to the peel portion 86 at a constant speed, each in-mold label 3 can be removed from the release sheet 2 at regular intervals. Further, for example, by reading the boundary between the transparent portion 3b of the in-mold label 3 and the non-transparent print layer 61 using a sensor or the like, each in-mold label 3 is desired while adjusting the feed timing of the continuum 1. It can also be removed at intervals.
The peeled in-mold label 3 is set at a predetermined position on a mold (not shown) of a known molding apparatus, and the melted resin material is placed in the mold. In the case of injection blow molding, a parison (corresponding to a molten resin material) is installed in the mold, and compressed air is blown into the parison. When the resin material comes into contact with the adhesive layer 5 of the in-mold label 3, the heat-sensitive adhesive constituting the adhesive layer 5 is activated and integrated with the resin material. In this way, an in-mold molded product in which the resin molded body and the in-mold label 3 are integrated can be obtained.
From the time when the in-mold label 3 is peeled off from the in-mold label continuum 1 until it is set in the mold, the back surface 5a of the adhesive layer 5 of the in-mold label 3 is prevented from coming into contact with foreign matter such as an apparatus member. Is preferable. By transporting the in-mold label 3 so that foreign matter does not come into contact with the back surface 5a of the adhesive layer 5, the in-mold label 3 having the adhesive layer 5 having excellent back surface smoothness can be incorporated into the resin molded body.
The molding method of the resin molded product (in-mold molded product) is not particularly limited, and examples thereof include known molding methods such as injection molding, blow molding, differential pressure molding, compression molding, and foam molding. Above all, when the resin molded body is formed by injection molding or blow molding, the in-mold label 3 can be satisfactorily integrated with the resin molded body, which is preferable. In particular, when a low-temperature active heat-sensitive adhesive is used as the adhesive layer 5, an in-mold molded product can be satisfactorily formed even by an injection blow molding method.

The in-molded product has a good appearance because the in-mold label 3 is integrally adhered to the resin molded product via the adhesive layer 5.
In particular, since the in-mold label 3 of the present invention has excellent smoothness on the back surface, it is difficult to become cloudy, and therefore, the transparent portion 3b of the in-mold label 3 has an excellent sense of unity with the resin molded body.
The present inventors have diligently studied the cause of the conventional in-mold label becoming cloudy, and found that the cause is that the back surface of the adhesive layer is roughened. Specifically, if there are relatively large irregularities on the back surface of the adhesive layer as in the conventional in-mold label, the adhesive layer is formed when the resin material, which is the material for forming the resin molded body, comes into contact with the back surface of the adhesive layer during molding. The convex portion of the adhesive layer is sufficiently melted, while the concave portion of the adhesive layer is not sufficiently melted, resulting in heating spots on the adhesive layer. In this state, when the resin material is cooled and the resin material and the adhesive layer are cured, an in-mold molded product is produced with relatively large irregularities remaining on the back surface of the adhesive layer. Therefore, in the in-mold molded product, the interface between the resin molded body (cured resin material) and the adhesive layer becomes uneven. If the back surface of the in-mold label is uneven as described above, the light that passes through the transparent part of the in-mold label or is reflected through the transparent part becomes a mixture of various refractive indexes, which is the cause. As a result, the transparent portion of the in-mold label appears cloudy, and its transparency is reduced.
In this respect, in the in-mold label 3 of the present invention, since the back surface 5a of the adhesive layer 5 is excellent in smoothness, heating spots of the adhesive layer 5 are less likely to occur during molding, and the interface between the resin molded body and the adhesive layer 5 is less likely to occur. A smooth in-mold molded product can be obtained. Since such an in-mold molded product is excellent in transparency of the transparent portion 3b of the in-mold label 3, the resin molded product can be visually recognized through the transparent portion 3b. In particular, the in-mold label 3 having a ten-point average roughness Rz of 3 μm or less on the back surface 5a of the adhesive layer 5 can obtain an in-mold molded product having excellent transparency in the transparent portion 3b.
Since the in-mold molded product of the present invention has excellent transparency in the transparent portion 3b, when the resin molded product is transparent, the transparency of the resin molded product is hindered in the transparent portion 3b of the in-mold label 3. It is excellent in the sense of unity between the label and the resin molded product, and is preferable in terms of appearance.

1 In-mold label continuum 2 Release sheet 2a Release surface of release sheet 3 In-mold label 3b Transparent part 4 Label base material 4A Label base material original fabric 5 Adhesive layer 5a Back side of adhesive layer 7A Laminated body

Claims (6)

It has an in-mold label having a label base material, an adhesive layer provided on the back surface of the label base material and composed of a heat-sensitive adhesive, a transparent portion, and a long strip-shaped release sheet.
A plurality of the in-mold labels are attached side by side with the back surface of the adhesive layer abutting on the release surface of the release sheet, and the adhesive strength of the adhesive layer to the release surface is 0.05 N / 15 mm. It is said to be ~ 0.7N / 15mm,
An in-mold label continuum in which the ten-point average roughness Rz of the back surface of the adhesive layer and the ten-point average roughness Rz of the release surface of the release sheet are 3 μm or less, respectively. The in-mold label continuum according to claim 1 , wherein the heat-sensitive adhesive contains an olefin-based elastomer. The in-mold label continuum according to claim 1 or 2, wherein the heat-sensitive adhesive is a low-temperature active type heat-sensitive adhesive. A melted heat-sensitive adhesive is interposed between the release surface of a long strip-shaped release sheet having a 10-point average roughness Rz of 3 μm or less on the release surface and the original fabric of the long strip-shaped label base material. A step of obtaining a laminate in which a release sheet, an adhesive layer made of a heat-sensitive adhesive, and a label base material raw fabric are laminated in this order.
By cutting the label base material raw material in the thickness direction, the label base material raw material is divided into a plurality of in-mold labels arranged in the longitudinal direction and having a transparent portion . A method for manufacturing an in-mold label continuum. The method for producing an in-mold label continuum according to claim 4, wherein the heat-sensitive adhesive contains an olefin-based elastomer. The method for producing an in-mold label continuum according to claim 4 or 5, wherein the heat-sensitive adhesive is a low-temperature active type heat-sensitive adhesive.

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