JPH0410856B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for adhering composite films, and is applicable to various foods, desiccants, deodorants, sanitary products,
It belongs to the technical field of bonding composite films that are used for a variety of purposes, such as packaging materials for disposable diapers and skin materials for glass wool insulation materials.

(Conventional problems) Conventional methods for adhering composite films include dry lamination using an adhesive, pouring molten polyethylene resin onto the film surface or between films and curing the adhesive, and applying a heat-sealing agent to the film surface. There are methods such as thermal lamination, in which they are layered and bonded under heat. However, in addition to the overlapping process, both methods require processing for adhesion, such as applying an adhesive or heat sealant, or pouring molten resin, which requires advanced technology and time. Moreover, in composite films that require gas permeability or moisture permeability (hereinafter simply referred to as fluid permeability), an adhesive layer such as an adhesive with micropores formed on the entire surface of the film material is used. As a result, there was a problem in that the composite film after adhesion required post-processing to cut through the holes.

(Purpose of the Invention) Therefore, the present invention provides an adhesion method that allows easy adhesion of film bodies and also ensures fluid permeability even when bonding film bodies provided with micropores for fluid permeability. . Therefore, the present invention provides a film that can adhere molten resin such as nonwoven fabric or paper to the outside of a plurality of plastic film bodies made of materials with different melting temperatures, a single plastic film body, or a plurality of plastic film bodies stacked together. (hereinafter referred to as molten resin adhesive film bodies) are stacked, and the outer surfaces of the stacked bodies are brought into contact with a soft elastic body, and heated to a temperature higher than the melting temperature of the other plastic film bodies, excluding the outer film body. By applying melt pressure from the inside of the heated protrusions so that they do not penetrate only the outer film, and then removing the protrusions, it is possible to intermittently create point pressure welds as welded parts using a large number of heated protrusions. This is a summary.

(a) Next, with the outer film body in contact with a soft elastic body, a projecting body is inserted and pressure is applied by indenting the film body into the elastic body by the pressure of the projecting body to create an appropriate pressing force. This is to prevent the projecting body from burning out the outer film.

(b) Furthermore, the reason why we did not pierce only the outer film with the protruding object was to form a composite film that does not require fluid permeability, and also to cut the outer film made of molten resin adhesive such as paper. This is because doing so will result in a product defect.

(Example) Hereinafter, details of the method of the present invention will be explained with reference to the drawings.

First, to explain the process shown in Fig. 8, film bodies A and B fed out from base paper rolls S and N are overlapped by a bonding roll 1, and then pasted through a guide roll and bonded by a pair of pressure rolls 2 and 3. The film is then wound onto the drum 4 as a composite film.

Next, the apparatus used for the characteristic bonding method in this example will be explained. As shown in Fig. 1, in a pair of crimping rolls 2 and 3, one hot needle roll 2 is a roll that is heated to 100°C or higher by a heating device (not shown), and there are many rolls on the outer circumferential surface. The projecting body K,
... are protruded at regular positions. The protruding body K has a needle shape, and its tip has a diameter of 0.2 mm.

The other receiving roll 3 is a rubber roll having a releasable outer layer made of rubber, and can be controlled so that its surface temperature does not exceed 100°C using a water-cooled cooling device (not shown). The rubber of the outer layer should preferably have a hardness of 65 to 85 degrees; if the hardness is more than 85 degrees, the elasticity of the roll 3 will decrease and holes will be formed by the pressure of the projections K, which is bad. The best range is a soft elastic body with an angle of 65 to 75 degrees. In this example, one film body A is a perforated polypropylene film with countless micropores, and the other film body B is a perforated polyester film.The two film bodies A and B are stacked and melted. The film body B side (outside), which has a higher temperature, is applied to the receiving roll 3 and passed between the rolls 2 and 3.

According to the method of this example, since the projecting body K of the hot needle roll 2 is heated to a temperature higher than the melting temperature of the polypropylene resin, the projecting body K melts through the film body A, which has a low melting temperature, as shown in FIG. Film body B is made not to pierce through. This can be controlled by adjusting the gap between the projecting body K and the receiving roll 3, the temperature of the projecting body K, or the pressing force of the projecting body K. At this time, the film body is pressed by the projecting body K, but since the receiving roll 3 is made of a soft elastic material, the pressed portion is depressed by about 0.1 to 1 mm and escapes, so that the pressing force by the projecting body K is adjusted. Therefore, the projecting body K is attached to the film body B.
No holes are formed through the holes. Incidentally, since the temperature of the projecting body K is lower than the melting temperature of the film body B, the film body B is not fused.

When the projecting body K comes out, both film bodies A and B are welded together at that location as shown in FIG. Since this welding is performed at the portion where the projecting bodies K are arranged, the entire film is intermittently spot-pressure welded, so that it is bonded to form a composite film. As shown in FIG. 3, the welded portion is formed by melting the point pressure area caused by the projections K of the film body A and welding it to the film body B in a net-like or granular composition.

In this way, according to this example, since the holes in film bodies A and B are not blocked except for the welded parts, fluid permeability can be ensured in the composite film, and post-processing for making micro-holes as in the conventional method is not required. I don't.

According to experiments, the tip surface diameter of the protrusion K is 0.2 mm, the adhesion density by the protrusion is 1 cm ₂ at 100 locations, the inner film A is made of polypropylene (melting temperature 240°C) with a thickness of 20 microns, and the outer film B is made of polyester. (melting temperature 260℃), thickness 20 microns, film advancing speed 20m/min, temperature of receiving roll 3
100℃, heating temperature of the protrusion 250℃, and pressing time of the protrusion
It was possible to adhere to a composite film with sufficient peel strength in just 0.2 seconds.

From other experiments, the tip surface of the protrusion has a diameter of 0.1 to 5 mm.
Even if the welding is good, if the point pressure area exceeds 5 mm, the welding becomes poor due to the influence of the amount of heat.

Note that the outer film body that is not melted by the projecting body is stretched because it receives heat conduction and is pressed, and by increasing the heating temperature of the projecting body and the pressing force of the projecting body, a fourth As shown in the figure, pinholes P or pinhole-like through holes of several microns to several hundred microns can be freely formed. Since this pinhole P is permeable to gas and not permeable to moisture, it is possible to form a composite film having fluid permeability even when the film bodies A and B are made of impermeable film materials.

Next, in the present method shown in FIG. 5, three plastic films C, D, and E are bonded together, and the film bodies are stacked from the inside in descending order of melting temperature, and the outer film body E, which has a high melting temperature, The heated projecting body K is inserted from the inside with the film in contact with the elastic body, and when the projecting body K reaches the outer film body E, the projecting body K is pulled out. In this case, the optimum heating temperature for the projecting body K is at the melting position of the central film body D. As a result, as shown in Fig. 6, the point pressure areas created by the protrusions of the inner and central film bodies C and D are melted and mixed and welded to the outer film body E, thereby bonding the three film bodies together. .

In addition, when three or more plastic film bodies are combined, the heating may be set to the melting temperature of the film body which has a higher welding temperature of the other film bodies excluding the outer film. Therefore, it is not necessary to stack the film bodies in order of decreasing melting temperature as in this example.

(Structure of the Invention) Each of the embodiments is a method as described above, but the method of the present invention is not limited thereto. For example, the film bodies other than the outer film body on the side that contacts the elastic body are required to be meltable plastic films, but the outer film bodies may be made of resin nonwoven fabric, paper, aluminum foil, etc. other than plastic. That is, the outer film body may be made of any material that can be welded and bonded to the molten resin of the plastic stacked by the projecting bodies. By gluing paper or non-woven fabric to the outside, you can create a material that can be heat-sealed with the plastic film on the inside, and it also prevents paper dust from adhering to the packaged items, and also prevents moisture, moisture, oil, etc. from dripping from the packed items. The paper material absorbs water and prevents the stored items from rotting or becoming sticky.
Furthermore, since it ensures breathability, it prevents condensation and can be used for multiple purposes such as cooking materials and sanitary materials.

Further, the material of the soft elastic body with which the outer surfaces of the stacked film bodies come into contact is also suitable.

Further, the configuration and shape of the protruding body may be arbitrary, and the protruding body may be inserted by moving forward and backward in a straight line as shown in FIG. Note that the heating temperature of the protrusions should be higher than the melting temperature of the other film bodies except the outer film body, and the outer protrusions should not melt the film body even if the temperature is higher than the melting temperature of the outer film body. You can use it if you adjust it. Moreover, the thickness of the composite film body is not strictly interpreted, and may be film-like.

In short, the present invention involves stacking a plurality of plastic film bodies made of materials with different melting temperatures, or stacking a molten resin adhesive film body such as nonwoven fabric or paper on the outside of a single plastic film body or a plurality of plastic film bodies stacked together. , with the stacked outer surfaces in contact with a soft elastic body, do not pierce only the outer film with a number of protrusions heated above the melting temperature of the plastic film bodies other than the outer film body. This is a composite film bonding method in which point-pressure welding parts using a large number of heated projecting bodies are intermittently provided as welding parts and bonded by removing the projecting bodies after applying melt pressure from the inside.

(Effects of the Invention) Therefore, the method of the present invention has the following effects.

(a) Since a meltable plastic film is used as the film body to be welded, it can be welded as is with a heated projecting body without applying a heat sealant as in the past. For this reason, adhesion of three or more film bodies can be completed in a single work step, and a composite film can be rapidly formed, which is highly effective. In this regard, in the past, the bonding process was repeated to produce a composite film, which took a long time.

(b) The film surface is intermittently bonded because the adhesive part is welded only at the point pressure area caused by the protrusion.
Another great advantage is that it is not necessary to apply adhesive or curing agent to the entire surface of the film, and the adhesion work is simple.

Another advantage is that the state of adhesion can be determined instantaneously. In this regard, when using adhesives, the state of adhesion cannot be inspected until after the curing time (12 to 24 hours) has elapsed. In addition, since no adhesive or chemical is used, there is no secondary pollution due to the generation of harmful gases, and since no adhesive is used, there are no restrictions on the applications. Furthermore, since the adhesive is welded, it has excellent adhesive strength and does not peel off due to external conditions such as moisture. Moreover, since the adhesive is welded, if a transparent film body is used, transparency can be maintained even as a composite film.

(c) Even in the case of a composite film using a fluid-permeable film body, the present invention has the effect of ensuring fluid permeability due to intermittent adhesion. In this respect, in the conventional method, since the adhesive layer is bonded over the entire surface of the film, the adhesive layer loses fluid permeability, and therefore requires post-processing to create micropores, which is time-consuming.

(d) A pin pole can be formed on the outer film body pressed by the protrusion by adjusting the heating temperature of the protrusion or the pressing force of the protrusion, and the film body is made of an impermeable material. However, it is possible to create a composite film that has air permeability due to the pin poles in the bonded portion.

(E) In addition to making a plastic composite film, by using nonwoven fabric, paper, aluminum foil, etc. as the material of the outer film body, it is possible to make a composite film that can be used for various purposes as well as various packaging materials.

[Brief explanation of drawings]

The drawings are for explaining the present invention, and FIG. 1 is a perspective view showing the bonding process, FIG. 2 is an enlarged longitudinal sectional view of the main part, and FIG. 3 is a composite film showing the state of the bonded part. 4 is an enlarged sectional view of a composite film with pinholes formed therein, FIG. 5 is an enlarged vertical sectional view showing the bonding process of a composite film made of three film bodies, and FIG. FIG. 7 is an enlarged sectional view of the bonding part of the film, FIG. 7 is an enlarged sectional view of the main part showing another example of the bonding method, and FIG. 8 is a diagram of the manufacturing process of the composite film. 2... Hot needle roll, 3... Receiving roll, K... Projection, A, C... Inner film body, D... Center film body, B, E... Outer film body, P...
…Pinhole.

Claims (1)

[Claims] 1. A plurality of plastic film bodies made of materials with different melting temperatures are stacked, or a molten resin adhesive film body such as nonwoven fabric or paper is placed on the outside of one plastic film body or a plurality of plastic film bodies stacked together. With the overlapped outer surfaces in contact with a soft elastic body, a large number of protrusions heated to a temperature higher than the melting temperature of the other plastic film body excluding the outer film body are used to pierce only the outer film body. By removing the protruding body after melting pressure from the inside,
A method for adhering composite films, which comprises bonding by intermittently providing point-pressure welding parts as welding parts using a large number of heated protrusions. 2. The bonding method according to claim 1, wherein the heating temperature of the projecting body is higher than the melting temperature of the inner film member and lower than the melting temperature of the outer film material. 3. The elastic material that contacts the outside of the stacked film bodies is formed of a rubber roll equipped with a cooling device, and a large number of protrusions are provided protruding from the outer periphery of the roll facing the rubber roll, and the elastic material is passed between the two rolls. The bonding method according to claim 1 or 2, wherein the bonding method is performed by welding.