JPS61199930A - Bonding of composite film - Google Patents

Abstract

PURPOSE:To provide a bonding operation, which ensures the permeability to fluid, by a method wherein a large number of projections, which are heated up to a temperature higher than the melt temperatures of plastic film bodies except the outside film body, melt-press from inside in such manners as only not to pierce the outside film. CONSTITUTION:Perforated polypropylene film, on which an infinite number of micropores are sparsely provided, is employed as a film body A, while perforated polyester film is employed as a film body B. The film bodies A and B are piled up and past through between rolls 2 and 3 in such a manner that the backing roll 3 contacts with the side of the film body B, the melt temperature of which is higher than that of the film body A. Because each projection K of the hot roll with roller 2 is heated up to a temperature exceeding the melt temperature of polypropylene resin, the projection K pierces through the film body A while being melted but can not pierce through the outside film body B. Though the film body is pushed by the projection K, because the backing roll 3 is of elastic material, the portion to be pushed is released by falling in, resulting in controlling the pushing force developed with the projection K and sparsely providing with no hole produced by the piercing of the projection K on the film body B.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for adhering composite films,
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 of bonding composite films include dry lamination using an adhesive, pouring molten polyethylene resin onto the film surface or between films to cure and bond, and stacking a film coated with a heat sealant on the film surface. There are methods such as thermal lamination, which involves heat-compression bonding. However, in addition to the overlapping process, all of these 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), adhesives such as adhesives in which micropores are formed on the entire surface of the film material are used. Since the holes are blocked by the layer, there is a problem in that the composite film after adhesion requires post-processing to create fine holes.

(Objective of the Invention) Therefore, the present invention provides an adhesion method that allows easy adhesion of film bodies and ensures fluid permeability even when bonding film bodies provided with micropores for fluid permeability. . For this reason, the present invention provides a film to which a molten resin such as nonwoven fabric or paper can be bonded 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 melt-pressing the many protruding bodies from the inside so as not to pierce only the outer film, and then removing the protruding bodies, it is possible to intermittently create point pressure welds as welded parts by a large number of heated protruding bodies and bond them. This is a summary.

(a) Next, with the outer film body in contact with the soft elastic body, the projecting body is inserted and melted, and the film body is depressed 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 fuse and cut the outer molten resin adhesive film such as paper. This is because doing so will result in a product defect.

(Example) The details of one method of the present invention will be explained below with reference to the drawings.

First, to explain the process shown in FIG. 8, the base paper rolls S, N
After the film bodies A and B fed out are superimposed on each other by a joining roll 1, they are pasted together by a pair of pressure rolls 2.3 via a guide roll, and wound onto a 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 has many protrusions on its outer circumferential surface. It has ... protruding from its body at regular positions. The protrusion has a needle shape, and its tip has a diameter of 0.
It is 2■.

The other receiving roll 3 is a rubber roll with a releasable outer layer made of rubber, and its surface temperature can be controlled to not exceed 100° C. using a water-cooled cooling bag 21 (not shown). The rubber of the outer layer should preferably have a hardness of 65 to 85 degrees; if the hardness exceeds 85 degrees, the elasticity of the roll 3 will decrease and holes will be formed through the projections, which is bad.The best range is A soft elastic body with an angle of 65 to 75 degrees is preferable, and 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. use,
These two film bodies A and B are overlapped, and the film body B side (outside) having a high melting temperature is applied to the receiving roll 3, and the film body is passed between the rolls 2.3.

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 concentrates on 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 protruding body and the receiving roll 3, the temperature of the protruding body, or the pressing force applied to the protruding body. On this occasion,
The film body is pressed by the projecting bodies 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 inch and escapes, so that the pressing force by the projecting bodies K is adjusted. Therefore, the projecting body K does not pass through the film body B to form a hole, and since the temperature of the projecting body is below the melting temperature of the film body B, the film body B is not cut by melting.

When the protruding body K comes out, both film bodies A are shown as shown in Figure 3.
, B are welded at that location. Since this welding is performed at the disposed portion of the projecting body, the entire body 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, the pores of film bodies A and B are not blocked except for the welded parts, so fluid permeability can be ensured in the composite film, and post-processing to create micro-holes is not required as in the conventional method. I don't.

According to experiments, the tip surface diameter of the protrusion was 0.2 mm, the adhesion density by the protrusion was 1 cm2 at 100 locations, and the inner film body A was made of polypropylene (melting temperature 240°C) with a thickness of 2 mm.
The outer film body B is made of polyester (melting temperature 260°C) and has a thickness of 20 microns, and the film travels at a speed of 20 m/min.

From other experiments, we were able to bond to a composite film with sufficient peel strength when the temperature of the receiving roll 3 was 100°C, the heating temperature of the protrusions was 250°C, and the suppression time of the protrusions was 0.2 seconds. A diameter of 0.1 to 5 mm is good, but if the point pressure area is 5 mm or more, 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 receives heat conduction and is stretched because it is pressed. This means that pinholes P or pinhole-like through holes of several microns to several hundred microns can be freely formed. Since this pinhole P is a circulating type that does not allow moisture to pass through, it is possible to form a composite film having fluid permeability even when the film bodies A and B are made of an impermeable film material.

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 film body E, which has a high melting temperature on the outside, The heated protrusion K is inserted from the inside with the elastic body in contact with the elastic body, and when the protrusion K reaches the outer film body E, the protrusion K is pulled out. In this case, the optimum heating temperature for the projecting body is the melting temperature of the central film body.
, D are melt-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 should be set to the melting temperature of the film body that has a higher melting temperature of the other film bodies excluding the outer film. Therefore, as in this example, It is not necessary to stack the film bodies in order of decreasing melting temperature.

(Structure of the Invention) Each of the embodiments is a method as described above, but the method of the present invention is not limited to these. For example, the film body other than the outer film body on the side that contacts the elastic body is a meltable plastic film. Although certain conditions are required, the outer film body may be made of resin nonwoven paper, aluminum foil, etc. in addition to plastic.

In other words, the outer film body may be made of a material that can be welded and bonded by the molten resin of the overlapping plastics by the projecting body, and the material of the soft elastic body that abuts the outer surfaces of the overlapping film bodies is also suitable. .

The structure and shape of the protrusions are arbitrary, and the protrusions may be inserted by moving them linearly forward and backward as shown in Figure 7.The heating temperature of the protrusions is different from that of other films except for the outer film body. Even if the temperature is higher than the melting temperature of the outer film body, it can be used as long as it is adjusted so that the outer projecting body does not melt the film body. Moreover, the thickness of the composite film body is not strictly interpreted, and may be in the form of a film.

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, a number of protrusions heated to a temperature higher than the melting temperature of the other plastic film body except for the outer film body are pressed against only the outer film. This is a composite film bonding method in which point-pressure welding parts of a large number of heated projecting bodies are intermittently provided as welding parts and bonded by applying melt pressure from the inside so as not to pull out and then pulling out the projecting bodies.

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

(a) Fusible plastic 2 as a film body to be welded
Because it uses Kufilm, it can be welded directly with a heated projecting body without applying a heat sealant like 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 quickly formed, which is highly effective. In this regard, in the past, the bonding process was repeated to form a composite film, which took a long time.

(u) The film surface is bonded intermittently because the adhesive part is welded only at the point pressure point of the projecting body, so there is no need to apply adhesive or hardening agent to the entire surface of the film surface, making it easy to bond. The effect of being in the cylinder is also great.

Another advantage is that the state of adhesion can be determined instantaneously.

When using adhesive, its curing time (12~
The adhesion state cannot be inspected until 24 hours have passed. Furthermore, since no adhesives or chemicals are used, there is no secondary pollution caused by the generation of harmful gases.

Furthermore, since no adhesive is used, there are no limitations on the uses. Furthermore, since the adhesive is welded, it has excellent adhesive strength and does not peel off due to external conditions such as moisture.Furthermore, since the adhesive is welded, it can maintain transparency as a composite film if a transparent film body is used. be.

(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, the adhesive layer loses fluid permeability due to adhesion over the entire surface of the film, requiring 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 suppressing force of the protrusion, and even if the film body is made of an impermeable material. The pinholes in the bonded area make it possible to create a composite film with air permeability.

(:4) In addition to making a plastic composite film, by using a non-woven paper, aluminum foil, etc. as the material of the outer film body, it can be made into 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; FIG. 1 is a perspective view showing the adhesion process, FIG. 2 is an enlarged vertical sectional view of the main part,
Figure 3 is an enlarged sectional view of the composite film showing the state of the bonded part, Figure 4 is an enlarged sectional view of the composite film with pinholes formed, and Figure 5 is the bonding process of the composite film consisting of three film bodies. FIG. 6 is an enlarged longitudinal sectional view of the adhesive part of the composite film, FIG. 7 is an enlarged longitudinal sectional view of the main part showing the separate bonding method, and FIG. 8 is a manufacturing process diagram of the composite film. . 2: hot needle roll, 3: receiving roll, ni: projecting body, A, C: inner film body. D = central film body, B, E: outer film body, P: pinhole.

Claims (3)

[Claims] (1) Layering a plurality of plastic film bodies made of materials with different melting temperatures, or overlaying 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; With the outer surface of the plastic film 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 except for the outer film body are inserted from the inside so as not to pierce only the outer film. 1. A method for adhering a composite film, characterized in that after applying melt pressure, the projecting members are removed, and bonding is performed by intermittently providing point-pressure welding parts as welded parts by a large number of heated projecting members. (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 abuts 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 on the outer periphery of the roll facing the rubber roll to pass between the two rolls. The bonding method according to claim 1 or 2, wherein the bonding method is performed by welding.