JPH0480819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a method for laminating a plastic film on the surface of printing paper or the like by a simple means without using ordinary adhesives, organic solvents, etc.

(Prior art) The method of laminating plastic film on the surface of printing paper, etc. using ordinary adhesives and organic solvents has been used for a long time, but there are problems such as pollution, so it is not necessary to use organic solvents. A lamination method was requested.

Therefore, the present applicant previously proposed a laminating method that solved the above problems in Japanese Patent Application Laid-Open No. 59-24669. This method uses a heated metal roll and a pressure roll to heat-press and laminate a print lamination film consisting of at least two layers, a base film layer and a heat-sensitive adhesive resin layer, with a printing paper or the like.

(Problems to be Solved by the Invention) However, in the above method, the surface of the base film layer was insufficiently glossy because it was only instantaneously thermocompressed between a heated metal roll and a pressure roll.

In view of the above, an object of the present invention is to provide a method for manufacturing a printed laminated product having a base film layer with good gloss and excellent smoothness.

(Means for Solving the Problems) In order to achieve the above object, the present invention uses a heated metal roll and a pressure roll, and provides a film for print lamination consisting of at least two layers, a base film layer and a heat-sensitive adhesive resin layer. In a method of thermocompression laminating a film and printing paper, etc., the outer periphery of a first heated metal roll provided along the film transport direction and a second heated metal roll whose temperature is higher than that of the roll is mirror-finished. A first crimping part and a second crimping part are constructed by stretching a metal endless belt and providing a first crimping roll and a second crimping roll facing both heating metal rolls, respectively, via the metal endless belt. For print lamination, using a device made of A film and a printing paper, etc. are fed, and first they are laminated by thermocompression at the first pressure bonding section, and then the laminated material is transferred while being in close contact with the metal endless belt, and the residual heat of the metal endless belt is transferred. A method was adopted in which a printed laminated product with an even higher gloss was obtained by performing glossing using a laminate and then further heat-compression laminating at a second compression bonding section.

(Example) The present invention will be explained in detail below.

The film for printed lamination according to the present invention is a laminated film having at least two layers, a base film layer and a heat-sensitive adhesive resin layer, and the base film layer is made of polyolefin such as polypropylene, polyester, polyamide, Examples include stretched or unstretched films made of thermoplastic polymers having a higher melting point than the polymer forming the thermosensitive adhesive resin layer, and preferably biaxially stretched polypropylene films. can. In this case, the above-mentioned biaxially oriented polypropylene film is a polypropylene homopolymer with a boiling n-heptane extraction residue of 90% or more, a propylene-α-olefin copolymer with an α-olefin content of 5 mol% or less, or It is preferable to use a mixture of a propylene homopolymer and a propylene-α-olefin copolymer blended so that the total propylene content is 95 mol% or more. Preferably, the layer is made of the above-mentioned polypropylene resin. There are no particular restrictions on the thickness of the base film layer, but a thickness of about 10 to 20 μm is usually preferred. Products to which a kinging agent, stabilizer, ultraviolet absorber, antistatic agent, etc. have been added may also be used as required.

Further, the heat-sensitive adhesive resin layer laminated on the above base film layer is not particularly limited as long as it is a solvent-free type with a melting point lower than that of the base film, but it is preferably a polymer mainly composed of ethylene, Examples include polyethylene or a copolymer containing at least 70% by weight of ethylene, or a mixture of polymers with a total ethylene content of 70% by weight or more. The monomer to be copolymerized with ethylene at this time is not particularly limited, and any monomer that can be copolymerized with ethylene may be used. Such monomers include, for example, propylene, butene-1, hexene-1,
1. Examples include vinyl acetate, ethyl acrylate, and acrylic acid. Furthermore, those modified by copolymerization followed by hydrolysis or crosslinking with metal ions, and those obtained by grist polymerization of maleic anhydride or the like can also be used. However, the total ethylene content is 70
If the amount is less than % by weight, it is difficult to return the film waste generated in the film manufacturing process or the slitting process to the base film layer, for example, the above-mentioned polypropylene layer, and reuse it, which is undesirable from the viewpoint of resource saving.

This is because, if these are intentionally returned, the transparency, slipperiness, dimensional stability, etc. may be significantly deteriorated, and there is a risk that a polypropylene film that cannot be put to practical use may be produced. Therefore, the total ethylene content is at least 70
Weight %, more specifically weight %, can be cited as a desirable range. Of course, if the above-mentioned return is not taken into consideration, it goes without saying that it can be used even outside this range. Furthermore, in addition to the above-mentioned polymers mainly composed of ethylene, polymers mainly composed of propylene such as polypropylene, propylene-ethylene copolymers containing a large amount of propylene (for example, 60 mol% or more), and propylene-1-butene can be used. A polymer or the like may also be added. It is convenient to add these polymers containing propylene as a main component to improve lubricity and the like. In addition, lubricants, anti-blocking agents, stabilizers, colorants, ultraviolet absorbers, antistatic agents, other thermoplastic polymers, etc. may be added to the heat-sensitive adhesive resin layer to meet various requirements such as transparency and thermal adhesiveness. It goes without saying that the present invention can also be applied to substances added within a range that does not impair quality.

Any known method may be used to produce the print lamination film, which is a laminated film comprising a base film layer and a heat-sensitive adhesive resin layer according to the present invention. The thickness of the heat-sensitive adhesive resin layer may be appropriately selected depending on the smoothness of the surface of the printing paper, the required adhesive strength, etc., and is usually preferably 1 to 5 microns.
Although it does not prevent the use of materials with a thickness of 5μ or more, it results in an unnecessary layer thickness.

Although there are no particular restrictions on the heat-sensitive adhesive resin layer, it is desirable that the layer be subjected to surface treatment in order to impart thermal adhesion to printing paper and the like. Examples of such treatment methods include common chemical treatment, flame treatment, corona discharge treatment, etc., but corona discharge treatment is particularly effective, and among them, corona discharge treatment in a nitrogen atmosphere with an oxygen concentration of less than 20.9% by volume It is even more effective to do this. At this time, the effect is recognized when the residual oxygen concentration in the nitrogen atmosphere is less than 20.9 volume %, which is the oxygen concentration in air, and the lower the residual oxygen concentration, the greater the effect. % or less. Corona discharge treatment strength and film temperature during treatment may be selected appropriately depending on the desired adhesive strength, but usually 20 to 100 W/min.
m ² and a temperature of room temperature to 90° C. is preferred. Any known method may be used to create a nitrogen atmosphere, such as enclosing the entire corona discharge treatment mechanism in a box and replacing the air inside with nitrogen gas, or spraying nitrogen gas onto the corona discharge section through a slit or the like. can be exemplified. Further, there are no particular restrictions on whether the surface treatment to be applied to the heat-sensitive adhesive resin layer as required may be carried out before or after lamination. Further, the printing film according to the present invention may be formed by laminating a film layer made of an appropriate material on the base film layer, or by laminating an appropriate thermoplastic layer between the base film layer and the heat-sensitive adhesive resin layer. Of course, a three-layer structure or a three-layer structure or more may be formed by interposing a combined layer, for example, an intermediate layer made of a propylene-based copolymer containing propylene as a main component.

Next, the method of the present invention will be explained with reference to the drawings. FIG. 1 is a general side view of a preferred apparatus used in the method of the present invention, and FIG. 2 shows the main parts of a modified example of the same apparatus. First, referring to FIG. 1, reference numeral 10 indicates a paper feed section, in which a piece of printed paper 4, such as printed paper, is placed on a mounting table 6 with the printed side facing up in this embodiment. There is.

This mounting table 6 is movable up and down, and is adjusted so that the uppermost printed sheet 4 is substantially flush with the upper surface of a conveyor 12 provided substantially horizontally in front of the upper portion of the paper feed section 10. . Then, the printed paper pieces 4 are fed and arranged on the conveyor 12 by the action of a vacuum suction device (not shown) so that the opposing ends are successively overlapped as shown in FIGS. 3 and 4.
A first heated metal roll 21 is provided in front of the conveyor 12, that is, along the film transport direction.
A metal endless belt 16 with a mirror-finished surface is stretched around the outer periphery of a second heating metal roll 31 that is hotter than the roll 21, and both rolls 21, 3
1, a first pressure roll 22 and a second pressure roll 32 are connected to each other via a metal endless belt 16.
By providing the first crimping part 9 and the second crimping part 3
0 is configured.

As an example, the film 1 for print lamination according to the present invention is made up of a base film layer 2 and a heat-sensitive adhesive resin layer 3, as shown in FIG. The guide roll 13 is placed on an appropriate frame on the upper part of the section 9, and the guide roll 13 is
so that the heat-sensitive adhesive resin layer 3 of the film 1 is aligned with the printed surface of the printed paper strip 4 through the film 1, and the base film layer 2 is on the endless belt 16 side and the printed paper strip 4 is on the first pressure roll 22 side. By being supplied in this way, the printing paper piece 4 and the print lamination film 1 are laminated by thermocompression bonding at the first pressure bonding section 9 as shown in FIGS. 4 and 5B. At this time, the temperature and pressure of the first pressure bonding part 9 and the second pressure bonding part 30 may be determined as appropriate depending on the heat sensitivity of the thermosensitive adhesive resin layer 3 and the properties of the printing paper, etc., but preferably the temperature is 80 to 160°C. , a linear pressure of about 40 to 120 kg/cm is sufficient. However, as described above, it is necessary to keep the temperature of the heating metal roll 31 higher than that of the first heating metal roll 21.

Next, to explain the method of print lamination using this device, the metal endless belt 16 and the first
Between the pressure rolls 22, the base film layer 2 is placed on the endless belt side and the printing paper piece 4 is placed on the pressure roll 22 side, and the print lamination film 1 and the printing paper piece 4 are fed, and first the first pressure bonding is performed. The laminated intermediate product 5 is then transferred in close contact with the endless belt 16 to be polished, and then further heat-pressed and laminated in the second crimping unit 30. A printed laminated product 5 is obtained. That is, the laminated intermediate product 5 that has been thermocompressed and laminated in the first crimping section 9 is transferred to the second crimping section 30 in a state in which it is in close contact with the endless belt 16 due to the heat pressure during crimping. As a result, gloss is imparted to the surface of the lamination intermediate product 5, that is, the base film layer 2 of the film 1. At this time, if there is moisture in the printed paper strip 4, some of this moisture will generate air bubbles between the base film layer 2 and the printed paper strip 4;
A second heating metal roll 31 having a higher temperature than the first heating metal roll 21 of the first crimping unit 9
By thermocompression bonding again at the compression bonding section 30, the air bubbles are quickly removed to the outside through the printing paper strip 4, etc., and the base film layer 2 is further smoothed and glossy by the high temperature heat. is given.

Figure 2 shows the main parts of a modification (another embodiment) of Figure 1, and the differences from the one in Figure 1 are as follows:
An auxiliary pressure roll 35 is provided on the opposite side of the second heating metal roll 31 from the second pressure roll 32, and after thermocompression bonding in the second pressure bonding section 30, the second heating metal roll 31 runs on the surface of the second heating metal roll 31. As a result, even more gloss is added, the direction is changed by the auxiliary pressure roll 35, and the printed laminated product 5' is obtained by separating from the surface of the second heating metal roll 31. Note that the material of the auxiliary pressure roll 35 may be any other suitable material, but it may be normally the same as the second pressure roll 32.

Next, specific examples of the present invention will be described.

<Specific Examples> A melt-extruded film (thickness 750μ) of crystalline polypropylene was stretched 5 times in the longitudinal direction using a roll stretching machine at 130°C, and then an acrylic acid content of 5% by weight was applied onto the uniaxially stretched film. The ethylene-acrylic acid copolymer was melt-extruded and laminated to a thickness of 30μ, and then laminated in the transverse direction at 160℃ for 10 minutes.
A laminated film with a biaxially stretched polypropylene layer (base film layer 2) of 15 μm and an ethylene-acrylic acid copolymer layer (heat-sensitive adhesive resin layer 3) of 3 μm was obtained by stretching the film twice, and the ethylene-acrylic acid copolymer side was Film 1 for print lamination was obtained by corona discharge treatment at a film temperature of 40° C. and a treatment intensity of 40 W·min/m ² in a nitrogen atmosphere with a residual oxygen concentration of 0.5% by volume. The obtained film is slittered to a width of 780 mm.
mm, length 2000 m, and rolled up into a 3 inch paper tube.

The rolled film rolled up onto such a paper tube was set at a position 33 in the apparatus shown in FIG. After that, the length is 540mm from the paper feed section 10,
A printed paper strip 4 with a width of 786 mm is fed onto the conveyor 12 as described above with the printed side facing up, and the heat-sensitive adhesive resin layer 3 of the print lamination film 1 fed out from the other side and the printed surface of the printed paper strip 4 are The base film layer 2 was supplied to the endless belt 16 side, and the printed paper strip 4 was supplied to the first pressure roll 22 side, thereby being laminated by thermocompression by the first pressure bonding unit 9. The endless belt 16 used at this time was a stainless steel belt whose surface was mirror-finished. Also, the first heating roll 21
has a diameter of 450 mm and a temperature of 110°C, the first pressure roll 22
uses a rubber roll with a rubber hardness of 90 degrees and a diameter of 250 mm.
The crimping pressure was a linear pressure of 100 kg/cm. Subsequently, the thermocompression bonded laminated intermediate product 5 proceeded to the second compression bonding section 30. The second heating metal roll 31 has a diameter of 450 mm,
The temperature is 130°C, and the rubber hardness of the second pressure roll 32 is 90.
A rubber roll with a diameter of 250 mm was used, and the pressure was 70 kg/cm. Continuing with the cooling roll 14,
15 and is wound up at the winding section 7. And the speed of the laminating machine shown above is 30~40m/
It was possible to continuously obtain a bubble-free, glossy, and beautiful printed laminated product 5' at high speed in minutes.

<Comparative Example 1> Using the same printed lamination film 1 and printed paper strip 4 as in the specific example, thermocompression lamination was carried out using the apparatus shown in FIG. 6. The device shown in FIG. 6 is different from the device shown in FIG. 1 in the second crimping section 31 of the present invention.
The corresponding parts are rubber nip rolls 35, 36.
This point is made up of. The printed laminated product 5' manufactured according to FIG. 6 was glossy and beautiful, but it was a little inferior compared to that of the example, and there were air bubbles between the film 1 and the printed paper strip 4. Some portions remained and the smoothness was inferior to that of the example.

<Comparative Example 2> Thermocompression bonding lamination was carried out in the same manner using the apparatus of the example. However, in this case, the second heating metal roll 31
When the printed laminated products 5' were examined in two cases, one at the same temperature as the first heating metal roll 21 and one at a lower temperature, both were inferior to the example in terms of gloss.

(Effects of the Invention) The present invention provides a first
An endless metal belt with a mirror-finished surface is stretched around the outer periphery of a heating metal roll and a second heating metal roll whose temperature is higher than that of the heating metal roll. Using an apparatus in which a first crimping part and a second crimping part are formed by providing a first crimping roll and a second crimping roll, the substrate is placed between the metal endless belt and the first crimping roll. The material film layer is placed on the metal endless belt side, the printing paper etc. is placed on the first pressure roll side, and the print lamination film and the printing paper etc. are fed, and first they are laminated by thermocompression bonding at the first pressure bonding section, and then laminated with heat and pressure. The laminated product is transferred while being in close contact with the metal endless belt, and is polished using the residual heat of the metal endless belt, and then the second
By further heat-compression laminating at the crimping part, we have obtained a printed laminated product with even more gloss, so compared to the conventional method disclosed in JP-A No. 59-24669, the gloss is much better and there are no air bubbles. An excellent printed laminated product was obtained, with no deterioration in surface smoothness due to the occurrence of .

[Brief explanation of the drawing]

FIG. 1 is an overall side view of a preferred apparatus used in the method of the present invention, FIG. 2 is a side view of a main part of a modified example of the same apparatus, and FIG. 3 is a plan view showing the feeding state of printed paper pieces.
Figure 4 is a side view of the printed laminated product (including some film parts), Figure 5 A and B are A-A in Figure 4.
FIG. FIG. 6 is an overall side view of a comparative example. 1...Film for printed lamination, 2...Base film layer, 3...Thermosensitive adhesive resin layer, 4...Printed paper piece (printing paper, etc.), 5...Lamination intermediate product, 5'...Printed lamination product , 9...first crimping part, 16...metal endless belt, 21...first heating metal roll,
22...first crimping roll, 30...second crimping part,
31...Second heating metal roll, 32...Second pressure bonding roll.

Claims (1)

[Claims] 1. Using a heating metal roll and a pressure roll, at least 2 layers of a base film layer and a heat-sensitive adhesive resin layer.
In a method of thermocompression laminating a printed lamination film consisting of layers and printing paper, etc., on the outer periphery of a first heated metal roll provided along the film transport direction and a second heated metal roll whose temperature is higher than that of the roll, A first crimping section is created by stretching a metal endless belt with a mirror finish on the surface, and providing a first crimping roll and a second crimping roll facing both heated metal rolls, respectively, via the metal endless belts. and a second crimping part,
Between the metal endless belt and the first pressure roll, the base film layer is placed on the metal endless belt side and the printing paper etc. is placed on the first pressure roll side, so that the print lamination film and the printing paper etc. The laminated materials are first laminated by thermocompression at the first crimping section, and then the laminated materials are transferred in close contact with the metal endless belt and polished using the residual heat of the metal endless belt. A print lamination method characterized in that a printed laminated product with further added gloss is obtained by carrying out the following steps and then further thermocompression laminating in a second pressure bonding section.