FI121749B - Covers and process for making them - Google Patents

Description

Wrapping and method of making it

The present invention relates to a process for the preparation of a wrap or such protective film according to the preamble of claim 1.

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The wrapper or protective film to be manufactured generally consists of a polymer film having a length and a width intended to protect the product, whereby adhesive-filled recesses are formed in the polymer film. According to the method, recesses are formed in the polymer film, which are filled with adhesive, 10

The invention also relates to a wrapping process according to the preamble of claim 8 for making a self-adhesive film and to the use according to claims 13 and 14.

15 Household and laboratory thin polymer wells are used to protect dishes and products stored in them from oxidation, foreign odors, insect mold, etc.

Typically, these films are made of thin polyethylene (PE) plastic that is so thin that it bends around and attaches to the desired container mainly by the forces of van der Waals 20.

In many cases, however, this self-adhesion is not sufficient, especially if the surface is slightly damp or coarse (eg wooden container). Self-adhesion is not sufficient even when said product is used as a wrapper, e.g. for food, in which case it should be self-adhesive.

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2- For decades there has been a market for so-called. "Parafilm" that retains its shape when it is g tightened eg on a drinking glass. In this case, the polyethylene film is mixed with so much paraffin that the elastic modulus of the plastic is low and paraffin partially

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as glue per substrate when pressed. However, the parafilm has been wrapped

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30 with protective layers. The protective layer is removed when the product is used. By pressing the film O) o is made to adhere to the closure vessel. Paraffin film adhesive paraffin has a melting point of 60 ° C which limits its use. The product is mainly intended for laboratory use.

2, U.S. Patent 5,662,758, 1997 to Procter & Gamble Co., and subsequent U.S. Patents 5,871,607, 6,602,580, and 5,965,235, and WO-A-2007/1086028 A2, as well as U.S. Patent 5,672,780; 5,965,235 describes films printed with (by definition, '' conical '' or '' cup '') depressions with 5 glues on the bottom. The adhesive is '' pressure sensitive '', so that when squeezed at the desired point, the adhesive adheres to the substrate and holds the film there. Such a structure has the advantage that the well can be rolled into a consumer package without being caught. The recesses are made mechanically by pressing against a warm textured surface. When pressed, the patterned roll transfers the glue to the bottom of a conical or similar 10-cup recess.

US Patent Application 2003/10124281, for its part, describes a similar product in which a film is first coated with an adhesive layer and particles are sprinkled on it as much as they adhere to the adhesive. In order to obtain the adhesive property of the film as it is compressed, the film is stretched so warm that the distance between the separation particles increases to such an extent that the free adhesive layer between the particles can adhere to its substrate.

Both of the above basic applications require multi-step manufacturing and utilization of a variety of materials. Small particles can be cheap if they are, for example, calcium carbonate, but in the prior art they are prepared by emulsion polymerization. The particles have a typical diameter of <30 μιη.

In the aforementioned patent, the draw ratio, which provided sufficient distance between the particles, was 1: 3.85 according to the examples.

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g Similarly, a similar product made by another method has previously been patented - x refer in this respect to U.S. Patent No. 5,884,93, wherein the film is coated with a continuous Q_ adhesive layer and its surface is deactivated by irradiation or oxidation.

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30 (UV treatment, Ozone or Corona treatment). The product is then stretched so that the O) g deactivated layer is sometimes broken, and the areas between them are "" pressure sensitive "to bond.

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All of the above methods require expensive machineries and a multi-step manufacturing process.

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It is an object of the present invention to eliminate at least some of the problems associated with the prior art and to provide an entirely novel polymer film suitable for wrapping.

It is also an object of the invention to provide a process for making such a wrapper.

The invention is based on the idea of forming longitudinal grooves in the polymer film which are filled with adhesive.

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In the method, at least one groove is pressed on the polymer film with a heated press wheel to simultaneously transfer a pressure sensitive adhesive from the disc to one side of the polymer film opposite to the press wheel, which is pressed against the wheel to form a groove.

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The anti-press wheel side may have air pressure, a brush, a rotating, flexible sponge or, preferably, a die having a groove pressed by the hot press wheel on the molded polymer film.

More specifically, the process for making the wrapper or protective film according to the invention is essentially characterized in what is set forth in the characterizing part of claim 1.

The wrapper or protective film according to the invention, in turn, is characterized by what is shown in the characterizing part of claim 8.

The uses according to the invention, in turn, are characterized by what is set forth in claims 13 and 14.

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The invention provides considerable advantages. Accordingly, the invention provides a product which can be manufactured by a process which is inexpensive and which provides a product having greater transparency than the solution described in U.S. Patent Nos. 5,871,607, 5,662,758, and in particular 5,965,235.

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In the invention, a small amount of a wax containing an antifungal agent or, in special applications, a bacterial or antifungal chemical can be applied to the active side of the well where the adhesive layer is located. In this latter embodiment, the film may advantageously be used in the processing of fruit trees or in the removal of harmful branches, to protect the cutting point of the tree 5. Instead of wax brittle, breakable varnish can be used.

The invention will now be further explored by way of detailed description with reference to the accompanying drawings.

Fig. 1 is a schematic diagram showing a first embodiment of the method of the invention in a side view; Fig. 2 is a side elevational view (seen from the direction of the film width) of one preferred embodiment wherein the film first rotates some distance on the surface of the hot forming plate until it contacts the counter plate, which is to be cooled; Fig. 3 shows a detail of the embodiment of Fig. 1, applied to a case where a soft molding is used to form a film; Figure 4 is a schematic diagram of wax application; and Figure 5 illustrates how the structure of the film changes as it is stretched.

20 In Figures 1-5, the following reference numerals are used: 10, 20, 30, 40, 50 and 51 film material 12, 22, 32 press wheel (i.e. plate) 14, 34 press wheel rotation axis 16, 36, 47 adhesive dispensers δ 25 18,28,38 , 43 lords

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4- 29 counter plate i g 35 brush

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Figure 1 illustrates how the product is made by starting from a flat pit or foil 10,

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30 which is heated to soften sufficiently and then pressed into the groove O) o by a rotating narrow-headed plate 12, i.e. a press wheel. The disk rotation axis has

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reference number 14. Hot air is blown from below the plate. Adhesive is applied to the tip of the rotating plate 12 by a dispensing device 13, e.g. The prepared film is packed in such a way that the grooves in the adhesive do not overlap.

As shown in Figure 1, glue is dispensed onto the presser wheel 12 while a groove recess 18 is formed on the polymer film 5 and the adhesive is applied substantially to the free circumference of the presser wheel (i.e., the part of the ring that is not in contact with the polymer film).

In one preferred embodiment, the polymer film is maintained in contact with the hot presser wheel 10 so as to allow it to warm to 90-140 ° C, always according to the polymer film, before contacting the cooling counter-wheel.

In another embodiment, the rotating plates are hot in their hands and the pressing adhesive 15 colder.

In the third embodiment, after the previous operation, a thin layer of wax is applied over the entire well or, alternatively, only on the part which does not have an adhesive groove.

When the wax layer is brushed or sprayed on the entire film, the adhesive layer is released by using the product by stretching the product 90 degrees to its manufacturing direction, which opens the Himbeam, breaks the wax layer and releases the adhesive into contact with the substrate.

δ 25 As will be seen, the manufacture of the product of the invention is a ball

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simpler than the preparation of LO products according to the patents below, o x cc

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To make the product according to our invention, all you need is a roller table, the application of glue 30 to the roll brushes, and the heating of the press rollers. Heating of the press rollers can be done by electrical, infrared or hot oil circulation through the channels provided in the rolls.

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The film can be cooled by air blowing. After the press rollers have been formed into a groove on the polymer film to be treated, the deformation 6 can be promoted by means of a lower inflation pressure or, as mentioned above, a V-hole rotating counter roll or various hooks or rotating elastic sponges. Figures 2 and 3 illustrate a corresponding arrangement of the apparatus of Figure 1, wherein grooves (28, 38) are formed on the diaphragm 20 or 30, respectively, by the press wheel 22 and 32, the groove design 5 being promoted by said counter rollers 29 or ridges 35.

The tip of the press rollers pressed against the film to be molded may be rounded, flat or cup-shaped, depending on the type and viscosity of the adhesive used.

Preferably, the press roller roller may have a width of 0.5 to 1.0 mm and a roll diameter of 0.1 to 1.0 m, but the diameter is of no more importance than the fact that the large diameter ensures longer contact time on the films and the roll can be operated at lower temperatures. .

Any so-called "touch sensitive" adhesive can be used as an adhesive. adhesive adhesive, which is 15 edible, usually these are acrylic adhesives.

The polymer film may be any thermoplastic material such as a polyolefin (e.g., polyethylene, polypropylene, polybutylene), polyester (PET, PBT) or polyamide or a film formed by a copolymer. Preferably, polyethylene (HDPE, LDPE, MDPE, LLDPE) or polypropylene or polyethylene terephthalate or polyamide is used as the polymer film. Particularly preferred are thermoplastics having softening points in the range of 90-140 ° C.

It is also possible to use laminates, i.e., δ 25 layers of two or more polymer films.

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i o g Presser wheels can be metal or ceramic coated metal, x The coating of these presser wheels is important for how they dispense glue

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from the wheel surface to the surface of the polymer film. The surface of the presser wheel may also be porous,

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30 whereby the adhesive layer partially soaks into the surface and is removed from the polymer having a higher affinity σ> o. The porous surface is most easily achieved by spraying a metal oxide powder, such as alumina, with C 1 plasma.

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According to a particularly preferred embodiment, the polymer film is rotated at a certain angle on the hot press wheel and the cooling resist roller does not come into contact until later.

If the polymer film of the invention, which is already coated with grooves by adhesive, is sprayed with wax or brushed with wax, we have two embodiments available. Another option is that the entire surface of the film is waxed; the other is that no wax is applied over the glue grooves. Figure 4 shows the injection of wax from the nozzles 47 onto the surface of the film 40, whereby the wax accumulates in the grooves 43.

In an embodiment where the wax layer covers the entire surface, the adhesive is released only when the polymer film is stretched perpendicularly to the adhesive (see Figure 5, when the film 50 is stretched to a straight film 51, the adhesive is released). This case provides opportunities for a looser lime formulation. The adhesive can be fluid even at room temperature.

The wax layer according to the invention preferably contains mold control chemicals, for example benzoic acid or its salts, such as Na or K benzoate.

The protective film of the invention has a significant advantage over other similar products disclosed in the patent literature. It is clearly transparent if the distance between the glue grooves 20 is sufficient, e.g. 5 mm to 15 mm and the width of the glue grooves 0.5 to 1.0 mm.

For example, the product of U.S. Patent No. 5,965,235 is similarly non-transparent because a dense mesh of depressions prevents proper transparency. Transparency is important, for example, when packing food, because discoloration, mold and other deterioration caused by spoilage are detected even before the package or wrapping is opened.

δ i g According to our invention, a film solution that does not have wax on the grooves on the adhesive can be fixed to the substrate by pressing. A film with a wax layer can be

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in turn, attach by stretching and pressing. Normal, now in use

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30 household films, usually fixed by stretching and pressing.

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When the product of the present invention is intended for use in gardening, a layer of wax, such as paraffin wax, preferably beeswax or camauba wax, is suitable for protecting the sawn surface.

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The product can also be used to treat wounds in humans and animals, whereby the wax layer may have common anti-bacterial and bactericidal properties, which are achieved by methods known per se.

Other applications include porcelain and ceramic products such as washbasins and sanitary ware. In addition, the wrapper may generally be used as a protective film for flat surfaces, such as sheets, which may be made of metals, glass, wood and wood composites. As an example, various furniture boards can be specifically mentioned.

10 The protective film may also be in place during installation.

In the pharmaceutical industry, the wrapper or protective film according to the invention may be used as a torn version, e.g. for the treatment of severe open sores, burns. It can even be used as a wound dressing bandage / sticker and as a patch.

15 For applications in the automotive and electronics industries, the product is suitable, for example, as a surface film.

For outdoor use eg in the Commonwealth countries; tinplate for windows and doors and similar places to pull.

20 As a packaging material, the present wrapper is a suitable replacement material for cellular plastics when it is desired to obtain a thicker protective film. The advantages here are the ease of packaging - no need for gluing. Also suitable for candy boxes and tobacco boxes.

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Claims (14)

A method of making a wrapper consisting of a polymer film having a length and a width and intended to protect a product, according to which the process filled with glue is formed in the polymer film, characterized in that - it forms in the polymer film by pressing with a heated pressure wheel at least one latch into which pressure-sensitive adhesive is simultaneously transferred to a drum, and - on the other side of the polymer film, on the side located on the opposite side in relation to the printing wheel, a stop is arranged, with which the film is pressed against the wheel 10 to form the lock. Method according to claim 1, characterized in that the polymer film is pressed against the wheel with substantially the area of the pressure wheel with the impact. 15 Method according to claim 1 or 2, characterized in that the printing wheel is arranged in the vertical plane on the upper side of the polymer film and the abutment on the underside of the polymer film, the polymer film being pressed up substantially against the wheel by means of the abutment. Method according to any one of claims 1 to 3, characterized in that the stop consists of a spongy, rotating means or a rotating brush or a rotating, cooled drum provided with a v-shaped latch. Method according to any of claims 1-3, characterized in that glue is dispensed with the printing wheel at the same time as a resilient impression is formed in the polymer film. § 25 o 6. A method according to claim 5, characterized in that glue is dosed substantially on the free casing surface of the pressure wheel. X and CL Process according to Claim 5, characterized in that the polymer film is poured into contact with the CO S 30 the hot pressure wheel such that it is heated to a temperature of 90 DEG-140 DEG C. depending on the polymer film before coming into contact with a polymer film. cooling c \ in moth wheels. 8. Cover or corresponding protective film made according to any one of claims 1-7, characterized in that the prints comprise latches in the longitudinal direction of the film, the bottom of the latch being provided with glue. Cover according to claim 8, characterized in that it is substantially transparent and the adhesive barrier covers about 1 - 30%, preferably about 5 - 20%, of its surface. Wrap according to claim 8 or 9, characterized in that the adhesive side is waxed. Wrap according to any of claims 8-10, characterized in that wax is present only on the outside of the adhesive barrier. Cover according to any of claims 8-11, characterized in that the wax and / or adhesive contain disinfectants. 15 The use of a wrapper according to any of claims 8 to 12 for protecting vessels and products stored in vessels from oxidation, foreign odors, insects, mold and similar surface factors. The use of a wrapper according to any of claims 8-12 in the processing of fruit trees or in the removal of harmful branches to protect the cutting point on the tree. δ (M i δ i LO O X X CL CO 'd- LO O) O o C \ 1