JPH0321332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for laminating a plastic film onto the surface of printing paper or the like by a simple means without using ordinary adhesives, solvents, etc., and an apparatus for carrying out the method.

As is well known, printed materials such as paper cartons, publications, cards, posters, and other paper products (hereinafter referred to as "printed materials, etc.") require protection of the printed surface, water resistance,
Many products have a plastic film laminated on their surface for the purpose of imparting oil resistance, gloss, and beautification.In the industry, this process is referred to as "print lamination" or "print lamination."
It is called.

Conventionally, such print lamination involves applying an adhesive dissolved in an organic solvent to a plastic film in the coating section of a laminating machine, scattering the organic solvent through a drying process, and then bonding the adhesive-coated surface of the plastic film with printing paper, etc. It is made by thermocompression bonding. However, the method using organic solvents has problems in terms of work safety such as the risk of fire, as well as environmental protection such as the generation of odors and air pollution. There was a strong demand for a laminating method and equipment that did not require the use of. In addition, in the conventional method of glazing, when laminating is carried out by thermocompression bonding between a heated metal roll and a pressure roll, the adhesive is softened by heat, and as a result, the surface of the plastic film is smoothed by the mirror-finished heated metal roll, resulting in a glossy finish. This takes advantage of the fact that the color becomes like this, and naturally the higher the temperature, the better the gloss.
However, with the conventional method, it is impossible to completely remove the organic solvent contained in the adhesive applied to the plastic film, and there is some residual solvent, which foams due to heat during thermocompression bonding. On the other hand, in order to suppress foaming as much as possible, it is necessary to heat and press it at a low temperature, but this will result in a lack of luster, so there is no condition that satisfies both conditions of no foaming and gloss. Ta. That is, in the past, we had to settle for an unsatisfactory product with only slight foaming and a slight lack of gloss, which was a serious drawback in terms of product quality.

In view of this technical background, the present inventors developed a new print laminating method and first filed a patent application in 1983.
−208760 (Unexamined Japanese Patent Publication No. 59-24666)
(Refer to Publication No. 24669), the gist of which is ``a composite polypropylene film on which a heat-sensitive adhesive resin layer is laminated, and the heat-sensitive adhesive resin layer of the composite polypropylene film is fed so that the printed surface of printing paper or the like is aligned. This method uses a metal roll and a rubber roll to heat-press and laminate the product, and by implementing this method, the conventional problem of foaming during heat-press bonding has been solved, but further study is needed in terms of gloss. In other words, instantaneous thermocompression bonding is inevitably insufficient for achieving gloss, and although it is theoretically possible to apply gloss using a press, it complicates the process and reduces efficiency. It has not been possible to put it into practical use, and therefore, it has been necessary to consider a new method that can perform the glazing continuously with the thermocompression bonding process.

In view of these conventional technical problems, the present inventors
As a result of intensive research, we have invented a solvent-free print laminating method that does not cause foaming during thermocompression bonding and has a good gloss, as well as an apparatus for implementing this method.The main points of this invention are as follows. As a method for laminating a print lamination film consisting of a base film layer and a heat-sensitive adhesive resin layer with printing paper, etc., the first method is to laminate the base film layer between a heating roll and a pressure roll. At the same time, a printing paper or the like is placed on the pressure roll side and passed through, heat-compression laminated to produce a printed laminated rough product, and then this printed laminated rough product is placed on the base film layer side. The second point is to obtain a polished printed laminated product by running it on the roll surface of a heating roll. A printed laminated rough product is obtained by heat-pressing lamination in the first stage by disposing printing paper etc. on the first heating roll side and passing it through the first pressing roll side, and then this printed laminated rough product is made in the same manner as above A second stage of thermocompression lamination is performed using a second heating roll and a second pressure roll arranged in the second heating roll, and then this is run on the roll surface of the second heating roll and further on the roll surface of an auxiliary pressure roll. The present invention is an apparatus for laminating a printed lamination film consisting of a base film layer and a heat-sensitive adhesive resin layer with printing paper, etc., in which the base film side A first pressure bonding unit includes a first heating roll disposed on the substrate film side and a first pressure bonding roll disposed on the printing paper side, and a second heating roll disposed on the base film side and a first pressure bonding roll disposed on the side of the printing paper etc. It consists of a second crimping/polishing section consisting of a set of a second crimping roll and an auxiliary crimping roll disposed on the side.

The present invention will be explained in detail below.

The film for printed lamination according to the present invention is a laminated film having 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, or other thermoplastic material. An example of the film is a stretched or partially stretched film which is made of a polymer and has a higher melting point than the polymer forming the heat-sensitive adhesive resin layer, preferably a biaxially stretched polypropylene film. 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. It is preferable to use the above-mentioned polypropylene resin mixed with scraps.
There is no particular limit to the thickness of the base film layer, but it is usually
Films with a thickness of about 10 to 20 μm are preferably used, and the base film layer may be colored or surface-treated, or may contain lubricants, anti-blocking agents, stabilizers, ultraviolet absorbers, antistatic agents, etc. Those added can also be used as necessary.

The heat-sensitive adhesive resin layer to be 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 for example, polyethylene or ethylene with a melting point of at least 70% is used.
Examples include copolymers containing ethylene in an amount of 70% by weight or more, or mixtures of polymers in which the total ethylene content is 70% by weight or more. There are no particular restrictions on the monomer to be copolymerized with ethylene, as long as it is a monomer that can be copolymerized with ethylene. Examples include propylene, 1-butene, 1-hexene, vinyl acetate, ethyl acrylate, and acrylic acid. Furthermore, those modified by copolymerization followed by hydrolysis or crosslinking with metal ions, and those modified by graft polymerization with maleic anhydride or the like can also be used. However, when the total ethylene content is less than 70% by weight, it is difficult to return the film waste generated in the film manufacturing process or slitting process to the base film layer, such as a polypropylene layer, and reuse it, resulting in resource conservation. Not desirable from that point of view.

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
A desirable range is 85% by weight, more specifically, 85% by weight. 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. Additionally, the heat-sensitive adhesive resin layer contains lubricants, anti-blocking agents, stabilizers,
Products to which coloring agents, ultraviolet absorbers, antistatic agents, other thermoplastic polymers, etc. are added within a range that does not impair various requirements such as transparency and thermal adhesiveness and quality can also be used in the present invention. Needless to say.

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 the use of a layer with a thickness of 5 μm or more is not prohibited, 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 methods such as chemical treatment, flame treatment, and corona discharge treatment, 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 30 to 150 W/min.
^m2 , room temperature to about 90°C is suitable. 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-rich polypropylene copolymer.

Next, the method of the present invention and its preferred apparatus will be explained based on the examples shown in FIGS. 1 and 2. In the figure, reference numeral 19 indicates a paper feed section, and in this embodiment, a piece of printed paper 4, such as printed paper, is placed on a mounting table 39 with the printed side facing up, and the mounting table 39 is movable up and down. The uppermost printed paper piece 4 is always adjusted to be substantially horizontal with the surface of the conveyor 16. The printed paper strips 4 are placed on a conveyor 16' operated by a vacuum suction device (not shown) so that the opposite ends are successively overlapped as shown in FIG. First crimp part 11
The process proceeds sequentially. The first crimping section 11 is composed of a pair of an upper first heating roll 6 and a lower first crimping roll 8, and in this embodiment, the diameter of the former is 300 mm and the diameter of the latter is 250 mm. The film 1 for print lamination according to the present invention is composed of a base film layer 2 and a heat-sensitive adhesive resin layer 3, as shown in FIG. The film 1 is disposed in a feeding section 22 disposed at the upper part of the section 11, and passes through a guide roller 15 from there so that the heat-sensitive adhesive resin layer 3 is brought together with the printed surface of the printing paper strip 4. By feeding the printed paper strips 4 to the first heating roll 6 side and the other printed paper strips 4 to the first pressure roll 8 side, the printed paper strips 4 and the print lamination film 1 are instantaneously thermocompression laminated at the first pressure bonding section 11. will be administered. At this time, the temperature and pressure of the first pressure bonding part 11 may be determined as appropriate depending on the heat sensitivity of the thermosensitive adhesive resin layer 3 and the properties of the printed paper strip 4, but preferably the temperature is 80 to 160°C and the linear pressure is 40 to 120 kg/cm. About cm is fine.

If the thermocompression bonding is insufficient in the first crimping part 11,
In the second pressing/polishing section 12 in the next step, further thermocompression bonding may be performed to obtain a preferable thermocompression bonded laminated state. In this way, the printed paper piece 4 is laminated by thermocompression bonding at the first pressure bonding unit 11 and is laminated with print.
(hereinafter referred to as "printed laminated crude product") then enters the second pressing and polishing section 12, where it is thermally pressed and polished. Said second crimping and polishing part 12
consists of a second heating roll 7 at the top, a second pressure roll 9 at the bottom, and an auxiliary pressure roll 10 arranged above the second heating roll 7. In this embodiment, the diameter of the second heating roll 7 is is 600 mm, and the diameter of the second crimping roll 9 and auxiliary crimping roll 10 is 250 mm each.
It is. The printed laminated raw product 5 that has been thermocompression laminated in the first compression bonding section 11 as described above is further thermocompression bonded by the second heating roll 7 and the second pressure roll 9 of the second compression bonding and polishing section 12, and then In this embodiment, polishing is performed by running the roll surface of the second heating roll 7 half a circle. At this time, the temperature of the second heating roll 7 is not particularly limited and may be selected as appropriate as long as it is within a range that produces a pressing effect and a polishing effect.
Preferably, the temperature is about 100 to 160°C. Further, the pressing pressure between the second heating roll 7 and the second pressing roll 9 may be set as appropriate, but preferably the linear pressure is 20 to 120.
About Kg/cm is fine. There is no particular limit to the pressure force between the second heating roll 7 and the auxiliary pressure roll 10, but preferably the linear pressure is about 20 to 120 kg/cm.
The main purpose of this auxiliary pressure roll 10 is to smoothly send the printed laminated rough product from the second heating roll 7 to the next process.
If 0 is not present, as shown in FIG.
arrow 1 on the second heating roll 7 side due to its rotational force.
6'', there is a risk that the printed paper piece 4 and the heat-sensitive adhesive resin layer 3 may be partially peeled off as shown by the arrow 17''. When running on the roll surface of the roll 7, as shown in FIG. Although the adhesive strength of the resin layer 3 may be improved, peeling does not occur. Of course, depending on the temperature of the second heating roll 7, etc., there may be cases where the auxiliary pressure roll 10 is not required. In this way, the printed laminated rough product 5 passes through the second crimping and polishing section 12, becomes a printed laminated product 5', and is transferred to the cooling roll 1.
6, 17 and enters the winding section. At this time, the printing paper strips 4 are not continuous, only their ends overlap, but since the print lamination film 1 is a continuous long piece, the print lamination film portion is printed. It is necessary to cut it according to the length of the paper piece 4. The part to be cut out is usually done at the arrowed part in Figure 5, but you are free to make perforations or cuts in this part, and after winding it up, it can be stretched artificially to make individual prints. It may also be finished into a laminated product. Therefore, it is preferable that the film for print lamination be made of a material that can be easily avoided in the lateral direction, and when the above-mentioned biaxially stretched polypropylene film is used as the base film layer 2, this condition is met, but there are no particular restrictions on this. It is free and free. The perforations and incisions may be made using a well-known method, for example, between cooling rolls. Also, after making perforations or cuts, for example, the cuts are not made continuously through pinch rolls with different speeds,
They may be stacked as they are, and these cutting methods may be carried out by appropriately applying known methods. The first and second heating rolls 6 in this embodiment,
7 is not particularly limited, but a heatable metal roll is usually used, and preferably one with a hard chrome plating and mirror finish is good from the viewpoint of polishing. The first and second pressure rolls 8 and 9 and the auxiliary pressure roll 10 are also not particularly limited, but rubber rolls, nonwoven fabric rolls, etc. are usually used, and preferably rubber rolls with a rubber hardness of about 70 to 95.

Next, embodiments of the present invention will be described based on FIGS. 8A to 8D.

The first crimp portion 11 shown in FIGS. 8A to 8E is similar to that shown in FIGS. 1 and 2, but the polishing means is slightly different. In FIG. 8A, since the second heating roll 7 is arranged together with the guide roll 20 as the polishing part 13, the printed laminated rough product 5 only runs on the second heating roll 7 surface. This is how polishing is performed. In other words, this configuration
Compared to the illustrated example, the second pressure roll 9 and the auxiliary pressure roll 10 are not provided. FIG. Guide roll 2 so as not to touch heating roll 7
1 is arranged, and such a configuration has the advantage that, for example, even thin printed paper, which wrinkles more easily, is less likely to wrinkle.

In FIG. 8C, a second pressure bonding/polishing portion 12 is provided and a guide roll 20 is provided, but the auxiliary pressure bonding roll 10 is not provided. Above 8th
If necessary, the guide rolls 20 and 21 in Figures A to C may be made vertically and horizontally adjustable so that their positions can be adjusted.
The desired polishing effect may be obtained by appropriately adjusting the positions of the guide rolls 20 and 21 depending on the thickness feed speed, etc., and by varying the distance over which the printed laminated rough product 5 travels over the heating roll 6. good. At this time, the guide rolls 20 and 21 may be rotating rolls, cooling rolls through which water or the like is passed, fixed rolls, or other suitable rolls, but fixed rolls are more preferable in terms of their ability to prevent curling. That is, in the printed laminated product 5, the printed laminated film 1 tends to curl slightly toward the film side due to heat shrinkage during thermocompression bonding. Sometimes, a squeezing operation is applied from the side of the printing paper, etc. Therefore, it is understood that the use of the fixed roll is more desirable in terms of preventing curling.
At this time, the adjustment of the guide rolls and the type of guide rolls as described above may be applied to both guide rolls 20 on both sides in the case of FIG. There are no restrictions.

By adjusting the positions of the guide rolls 20 and 21 as described above and appropriately changing the distance that the printed laminated rough product 5 travels on the second heating roll 7,
The desired polishing effect can be easily achieved. FIG. 8 D has a second crimping and polishing part 12, but a third crimping roll 23 is added between the second crimping roll 9 and the auxiliary crimping roll 10. Figure E shows the second part in the polishing part 13.
The pressure roll 9 is not provided, but the auxiliary pressure roll 10 is provided, and even in each of the above embodiment variations, the temperature of the second heating roll 7, the second pressure roll 9
The crimping pressure (if provided) is also the same as in the examples shown in FIGS. 1 and 2.

As mentioned above, the present invention has been described in detail, but this is a preferred embodiment of the present invention, and it goes without saying that the described contents are not limited as long as they do not depart from the spirit of the present invention.

<Example> A melt-extruded film of crystalline polypropylene (thickness 750μ) was stretched 5 times in the longitudinal direction using a roll stretching machine at 130°C, and then 100 parts by weight of low-density polyethylene and ethylene content were placed on the uniaxially stretched film. 90% by weight ethylene-vinyl acetate copolymer
A heat-sensitive adhesive resin consisting of a mixture of 100 parts by weight,
Melt extrusion laminated to a thickness of 30μ,
Thereafter, it was stretched 10 times in the transverse direction at 160°C to obtain a laminated film with a biaxially stretched polypropylene film layer (base film layer) of 15 μm and a heat-sensitive adhesive resin layer of 3 μm, and the surface of the heat-sensitive adhesive resin layer was freed from residual oxygen. A film for print lamination was obtained by corona discharge treatment at a film temperature of 50° C. and a treatment intensity of 30 W·min/m ² in a nitrogen atmosphere with a concentration of 0.05% by volume.

The film thus obtained was slit to a width of 780 mm and a length of 2000 mm using a slitter, and wound up into a 3-inch paper tube. Then, the rolled film 26 rolled up on this base tube is placed in the first and second tubes.
It was set in the feeding section 22 of the device shown in the figure. After that, the printed paper strip 4 having a length of 540 mm and a width of 786 mm is transferred from the paper feed section 19 to the conveyor 1 as described above with the printed side facing up.
6', and the heat-sensitive adhesive resin layer 3 of the print lamination film 1, which is fed from the other upper feeding section 22, and the printed surface of the printing paper piece 4 are aligned, and the base film layer 2 is heated by the first heating. The printed paper pieces 4 were supplied to the roll 6 side so as to face the first pressure roll 8 side, and were laminated by thermocompression bonding by the first pressure bonding unit 11 . At this time, the first heating roll 6 has a temperature of 120°C and has a hard chrome plating and mirror finish on the surface, and the first pressure roll 8 is made of rubber with a hardness of 90°, and the pressure is The pressure was a linear pressure of 100 kg/cm.

Subsequently, the printed laminated rough product 5 that has been thermocompression bonded has the base film layer 2 on the second side, similar to the first press bonding part 11.
The printed paper strip 4 was placed on the heating roll 7 side and the second pressing roll 9 side, and the sheet proceeded to the second pressing and polishing section 12. The second crimping and polishing section 12 has the structure shown in Figs.
The 7 sides of the second heating roll, which was crimped at 120°C and heated to 120°C, were run, and then
By running 0, a beautiful glossy printed laminated product 5' was obtained. Next, cooling roll 1
6, and the connecting part of the printed paper strip 4 (arrow 4')
After making appropriate cuts with a cutter, the sheet was further passed through a cooling roll 17 and continuously wound up by a winding section 18. The speed of the laminating apparatus described above was 30 to 40 m/min, and it was possible to continuously produce glossy and beautiful printed laminated products at a considerable speed.

In addition, by using the polishing part 13 as shown in FIG. 8A instead of the second pressing and polishing part 12 of this embodiment, the print lamination is carried out at a temperature of the second heating roll 7 of 140°C and a speed of 30 to 40 m/min. When a product was produced, the product was beautiful and shiny, similar to the previous example.

As described above, according to the present invention, not only is high-speed operation possible, but also beautiful glossy printed laminated products can be created, and the quality of the products obtained is significantly higher than that of conventional methods and equipment that use solvent-based adhesives. This method is excellent in terms of performance, and its effects are significant as it improves on the shortcomings of the previously proposed method.

In particular, in the present invention, when laminating a print lamination film and printing paper, etc., the film is passed between a heating roll (first) and a pressure roll (first) as a first step, and a separate film is passed between a heating roll (first) and a pressure roll (first) as a second step. Run it on the roll surface of the installed heating roll (second), or
Separate heating roll (second) and pressure roll (second
) and a heating roll (second
Since the vehicle is to run on the surface of
Compared to products that do not require step-by-step processing, they can operate at higher speeds, and are also more adaptable to thick print lamination films and printing paper. It is possible to provide printed laminated products with good appearance (less occurrence of spots due to air entrapment by powder) and good appearance.

[Brief explanation of the drawing]

1 and 2 show one embodiment of an apparatus for carrying out the method of the invention, FIG. 1 showing a side view and FIG. 2 a plan view thereof. Fig. 3 is a plan view showing the feeding state of printed paper strips, Fig. 4 is a cross-sectional view of the film for print lamination, Fig. 5 is a side cross-sectional view of the print lamination product,
Figure 6 is a sectional view taken along the line A-A in Figure 5, Figures 7A and 7B are explanatory comparative diagrams showing the action of the auxiliary pressure roll, and Figure 8
Figures A to H are explanatory diagrams of other embodiments of the present invention. 1... Film for printed lamination, 2... Base film layer, 3... Heat-sensitive adhesive resin layer, 4... Printing paper etc. (printed paper piece), 5... Printed lamination crude product,
5'...Print laminated product, 6...First heating roll, 7...Second heating roll, 8...First pressure roll, 9...Second pressure roll, 10...Auxiliary pressure roll, 11... First crimping part, 12... Second crimping and polishing part, 13... Glazing part, 15... Guide roll.

Claims (1)

[Claims] 1. When laminating a print lamination film consisting of a base film layer and a heat-sensitive adhesive resin layer with printing paper, etc., the base film layer is heated between a heating roll and a pressure roll. At the same time, a printing paper or the like is placed on the pressure roll side and passed through, heat-compression laminated to produce a printed laminated rough product, and then this printed laminated rough product is placed on the base film layer side. A printed laminating method characterized by obtaining a polished printed laminated product by running it on the roll surface of a heated roll. 2. When laminating a print lamination film consisting of a base film layer and a heat-sensitive adhesive resin layer with printing paper, etc., the base film layer is first heated between a first heating roll and a first pressure roll. At the same time, printing paper or the like is placed on the first pressure roll side and passed through it to form a printed laminated rough product through first-stage thermocompression lamination, and then this printed laminated rough product is distributed in the same manner as described above. A second stage of thermocompression lamination is performed using the heated second heating roll and the second pressure roll, and then this is run on the roll surface of the second heating roll, and further run on the roll surface of the auxiliary pressure roll. A printed laminating method characterized in that a glazed printed laminated product is obtained. 3 A device for laminating a print lamination film consisting of a base film layer and a heat-sensitive adhesive resin layer and printing paper, etc., which comprises a first heating roll placed on the side of the base film and a first heating roll placed on the side of the printing paper, etc. A first crimping section consisting of a set of first crimping rolls, and a second heating roll arranged on the base film side, and a set of a second crimping roll and an auxiliary crimping roll arranged on the side of the printing paper, etc. A print laminating device comprising a second crimping and polishing section.