Erkki, Turunen
Olli
Erkki, Turunen
Olli
| 1. | A procedure for producing nonshrinkable gluing or coating film from hot melt (3), said gluing or coating film (1Φ.11) being deposited on the surface to be glued or coated, or between different surfaces, and being made adherent thereto by fusing with the aid of heat, characterized in that the gluing or coating film (10,11) is produced by depositing hot melt with the aid of a recessed roll (4) on a peeloff paper web (2,2a), from which the perforated, reticular hot melt .film may be peeled off to become a separate gluing or joining film (10,il), either immediately or later on in connection with the gluing or coating operation. |
| 2. | Procedure according to claim 1, characterized in that the reticular structure of the gluing or coating film (10,11) is regulated by changing the recess pattern (8) of the recessed roll (4). |
| 3. | Procedure according to claim 1 or 2, characterized in that the hot joining properties of the gluing or coating film (10,11) are regulated by changing the composition and physical properties of the hot melt (3) . |
The present invention concerns a procedure for producing non- shrinkable gluing or coating film from hot melt, said gluing or coating film being placed on the surface to be glued or coated, or between different surfaces, and made adherent thereto by fusing with the aid of heat.
In several branches of industry, for instance in the textile, packing and car industries, gluing or joining films are used for joining surfaces. Typically, this kind of "joining film" is activated with the aid of heat, whereby the film is used between the surfaces to be joined or on the surface to be modified. Gluing or coating films of this kind typically consist of thermo¬ plastic material, which has been shaped to film by applying the blowing method.
Because of the production method, it has been necessary to use plastic materials which melt at high temperature. Moreover, a problem has been the shrinking of the film in connection with fusing. Endeavours have been made to eliminate the last-mentioned drawback by performing the film mechanically.
The object of the invention is to teach an improvement in the procedures of prior art. The more detailed aim of the invention is to provide a procedure which enables non-shrinkable adhesive film to be produced from wax-like hot melts with very low melting point.
The aim of the invention is achieved by a procedure which is mainly characterized in that the gluing or coating film is produced by depositing hot melt with the aid of a recessed roll on a peel-off paper web, from which the perforated, reticular hot melt film can
be peeled off to become a separate gluing or joining film, either immediately or later on in association with the gluing or coating operation.
As taught in claim 2, the reticular structure of the gluing or coating film is regulated by changing the recess pattern of the recessed roll.
As taught in claim 3, the hot joining properties of the gluing or coating film are regulated by changing the composition and physical characteristics of the hot melt.
The invention is described in detail referring to an advantageous embodiment of the invention, presented in the figures of the attached drawing, but to which the invention is not intended to be exclusively restricted.
Fig. 1 presents an advantageous embodiment of the apparatus used in the procedure of the invention, in schematical elevational view.
Fig. 2 displays the recess pattern of the recessed roll.
The web-like peel-off paper 2 to be ciated comes from its own roll 1, or has been provided in the form of a circulating endless belt 2a. This peel-off web 2,2a is preferably silicon paper, polyester film or equivalent with good peel-off properties. In the next step, hot melt 3 is applied on the peel-off web, using a roll technique of prior art, the hot melt being dispensed with the aid of a recessed roll 4. The recesses of the recessed roll 4 have been filled in the trough 5 with hot melt melted by the aid of heat. As the recessed roll 4 passes a doctor blade 6 prior to the coating pressure step it will carry melt 3 in the recessed depressions only. When the rubber roll 7 presses against the web 2,2a and the recessed roll 4, the recesses are "emptied" onto the web 2,2a to be coated, and owing to the recess design 8 of the recessed roll 4, a reticular coating is formed on the web 2,2a. Subsequent to cooling 9, the glue or coating film that has
formed can be detached (peeled off) to become a separate web 10 or, if the coating is carried out applying separate unrolling 1, the resulting roll 11 will be a gluing/joining film which is accompanied by a peel-off substrate to be taken off In connection with joining only.
As an example, a reticular film may be mentioned which was produced on the experimental line of the company Rastle Ky using 922 ' 4-2 Hot
Melt Adhesive manufactured by UPACO ADHESIVE INC., with specific gravity 0.992 g/cm and melting point: start 95°C and end 104°C
(ASTME-28) . The recessed structure 8 of the roll 4 was rhombic with centre-to-centre axis lengths, respectively, 4 mm x 2 mm. The depth and width of the recesses were such that the basis weight of the
2 reticular film obtained was 60 g/m . The web being coated (the peel-off substrate) was silicon paper. With the gluing film produced, paper/paper and aluminium/paper combinations, among others, were joined together (laminated) without incurring any shrinkage.
It is understood, of course, that the invention is not restricted to the above example? the most varied reticular structures, and hot melts, can be used. For joining products which are difficult to glue, expedient types of hot melt are selected.
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