WO2003054100A1

WO2003054100A1 - Adhesive strip and a method for the production thereof

Info

Publication number: WO2003054100A1
Application number: PCT/EP2002/012548
Authority: WO
Inventors: Michael Feldhege; Michael Roreger; Malgorzata Kloczko; Iris Schnitzler
Original assignee: Ecs Environment Care Systems Gmbh
Priority date: 2001-12-21
Filing date: 2002-11-09
Publication date: 2003-07-03
Also published as: AU2002363851A1; DE10163617A1

Abstract

The invention relates to an adhesive strip comprising a non-adhesive support film and an adhesive material arranged thereon in the form of threads. Said adhesive material can be provided with an adhesive covering applied in order to protect against damage or undesired adherence. The adhesive strip has excellent adhesive properties, although only a fraction of the adhesive material is required in comparison to the amount of adhesive material required to cover an entire surface in the form of an adhesive layer.

Description

Adhesive strip and process for its manufacture

The adhesive strip comprises a non-adhesive carrier film and an adhesive compound thereon in the form of threads. The adhesive can be provided with an abhasive cover to protect it from damage or undesired adhesion. The adhesive composition can contain additional active ingredients.

Adhesive strips have been commercially available for decades and are known under brand names such as Tesa ^® or Post-it ^® . These adhesive strips consist of a non-adhesive carrier film (e.g. plastic or paper) and a layer of adhesive on it. This adhesive layer is applied over the entire surface or at least over the entire surface along the edge of the carrier film. Known adhesive strips are also so-called double-sided adhesive tapes (Duplocoll, Vitocoll). Sections of such adhesive strips are also referred to as labels.

The adhesive properties (in particular adhesion and cohesion, but also the so-called "tack") of adhesive strips can be largely influenced by changing the composition of the adhesive composition. This also depends on whether a one-component adhesive, a two-component adhesive or a multi-component One-component adhesives are polymers which contain monomer units which are capable of forming physical interactions and / or chemical bonds with the surface to be bonded.Two-component adhesives can consist of two different substances, each with the others are capable of forming physical interactions and / or chemical bonds. Finally, two-component or multi-component adhesives can also be composed of non-adhesive polymers and tackifiers.

All adhesive strips have in common that they are covered with a protective film for the purpose of storage. This is to avoid damage to the adhesive layer and to prevent the adhesive strip from sticking to a surface. In the simplest case, this protective film can be used with the non-adhesive carrier film be identical, e.g. B. when the adhesive strip is rolled up or stacked. The adhesive layer then touches both the underside of the non-adhesive carrier film and its top. If the adhesion of the adhesive layer is the same on both sides of the non-adhesive carrier film, it can be peeled off from both sides with the same amount of force. In this way, double-sided adhesive tapes, which consist of a single layer of adhesive, are stored. Particularly easy detachment from the protective film is possible if it is equipped with an abhesive treatment. A protective film can e.g. B. can already be equipped with an abhesive surface by applying a very thin silicone layer.

It is clear that in the event that the adhesive strip consists of a non-adhesive carrier film and an adhesive layer thereon, it can only be stored rolled up or stacked if one side (e.g. the underside) of the non-adhesive carrier film is covered by a stronger adhesive force is bound to the adhesive layer than the other side of the non-adhesive carrier film.

In many cases, however, the combination of non-adhesive carrier film and adhesive layer is provided with a separate protective film, optionally with an abrasive finish.

Suitable adhesives are natural and synthetic polymers, for example polyacrylates, polyvinyl ethers, poly (styrene-butadiene), polyesters, alkylated resins, phenolic resins, olefinic thermoplastic elastomers, ethylene-vinyl alcohol copolymers, polyvinyl chloride and its copolymers, polyvinyl acetals, polyimides, Casein, glue, gelatin, waxes, carboxymethyl cellulose, hydroxyethyl cellulose, polysiloxanes, etc.

Numerous processes are known for producing adhesive strips, some of which depend on the chemical nature of the adhesive. The most common - and at the same time the easiest to carry out - processes are coating and extrusion. In addition, there is vulcanization using chemical additives or high-energy radiation. When coating, a solution (containing at least one organic solvent) or a (water-containing) emulsion of the adhesive is generally applied over the entire surface of the non-adhesive carrier film. The solvent or water is then given the opportunity to evaporate. What remains is the adhesive layer on the non-adhesive carrier film. Adhesive strips are obtained from this by cutting or punching.

Solvent-free adhesives are used for extrusion. These must first be melted so that they are spreadable, i.e. H. assume fluid consistency. One therefore speaks of hot melt adhesives. The extrusion is also carried out over the entire area.

The known adhesive strips have the disadvantage that the full-surface coating requires a considerable amount of (sometimes very expensive) adhesive. In addition, when the adhesive is applied, in particular during extrusion, mechanical abrasion can take place, which is due to the fact that the application head touches the carrier film to be coated. If there is little contamination on the carrier film, it is very easy to create damaged areas in the adhesive layer.

The removal of a protective film from a very aggressively adhesive adhesive layer can sometimes be associated with an undesirably high expenditure of force in spite of a protective coating of the protective film. For example, peeling with great effort can also result in the adhesive layer itself being destroyed.

The object of the present invention is to provide an adhesive strip in which a considerable amount of adhesive material can be saved and which nevertheless has good adhesive properties. Another object is to provide a manufacturing method for such an adhesive strip. Another object is to provide an adhesive trap for insects, in particular crawling insects, in which the edge effect is avoided.

The task is solved by an adhesive mass, which is in the form of threads. This adhesive can adhere to one side of the non-adhesive carrier film so form an adhesive strip. In a further embodiment, the adhesive composition in the form of threads can be covered by a protective film. The area coverage achieved in this way can be 50 50%, preferably 30 30%. The weight per unit area of the adhesive composition can thereby be considerably reduced in comparison to conventional adhesive strips.

To produce an adhesive mass in threads, this is first brought to a flowable consistency and applied to at least two outlet nozzles on a movable base (an intermediate carrier, but preferably the non-adhesive carrier film). Transporting the movable base (the intermediate carrier, the carrier film) relative to the nozzles then ensures that the adhesive mass takes the form of threads. If necessary, solvents and / or water have to be removed. The procedure can be carried out without contact. Continuous application to the support is preferred, but discontinuous, e.g. B. an intermittent (i.e. with periodic interruptions) or clocked (i.e. divisible into different recurring work steps) application of the adhesive mass possible.

The adhesive compositions are commercially available, namely as granules or in the form of solid blocks. Solutions of adhesives in organic solvents (petrol, heptane, ethyl acetate, ethanol etc.) or emulsions in water can also be purchased.

In particular, pressure-sensitive adhesives, contact adhesives and hot-melt adhesives come into question as adhesive compositions, of which the hot-melt adhesives are preferred. Soluble, including thermoplastic and cross-linkable adhesives can be used. These adhesives include the polyacrylates, polysiloxanes, polyethylenes, polyisobutylenes, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, ethylene-vinyl acetate copolymers, polyamides, polyesters, vinyl resins, natural and synthetic rubbers known to those skilled in the art , Isocyanates, etc. Plasticizers, crosslinking agents, tackifiers etc. can be used as additives here. In special cases, the adhesive composition can also contain one or more active ingredients, which means dyes, pigments, insect attractants (attractants, pheromones) etc.

A thread in the sense of the present description is to be understood as an endless strand of material. This strand of material has a cross section dependent on the shape of the nozzle used in the manufacture. This is preferably circular or essentially circular; however, it can also be flattened due to the action of external forces. The thread can thereby assume a semicircular or substantially rectangular cross section. The thickness of the threads (i.e. their diameter or their greatest transverse dimension) can also be adjusted using the nozzle used in the manufacture. The thickness of the threads can thus be easily adapted to the intended application. Thicknesses of up to 1 cm or more are conceivable; when used for the private sector (for adhesive strips, labels, plasters, labels, etc.), a thickness of 0.05 mm to about 3 mm is generally sufficient. The threads preferably have a thickness between 0.1 mm and 1 mm. The minimum thickness of the threads is 10 μm. The threads can exist side by side without common nodes. However, this case requires the presence of an intermediate backing during manufacture or a non-adhesive backing in the adhesive strip. The threads are then arranged essentially parallel to one another. However, it is preferred that the threads have common nodes. These nodes arise when two threads come to lie on top of each other, while the adhesive still has a flowable consistency. When converting to the non-flowable consistency, a firm bond is then formed between the two threads at this point. This can result in a regular pattern (grid) or an irregular network.

Metals, natural or synthetic materials, composite materials etc. can be used as the non-adhesive carrier film. They can be in the form of a sheet material, preferably as an endless web. This endless path can be elastic and / or flexible. For example, aluminum, iron, copper, etc. can be considered as metals; as natural materials wood, cellulose, cotton, paper, glass, cardboard etc .; as synthetic materials Polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyacrylate, polyester, polyethylene terephthalate, polycarbonate, polyphene, etc .; as composite materials films that consist of several (ie at least two) different layers, eg. B. packaging materials, PET cardboard PET.

An object is to be regarded as an adhesive strip which has a non-adhesive carrier film and an adhesive composition in the form of threads. The adhesive mass present in threads adheres to one side of the non-adhesive carrier film, for example by physical and / or chemical adhesion. The adhesive in the form of threads in the adhesive strip can be covered by a protective film.

Flowable consistency means that the adhesive mass is brought into the form of a melt, a solution or an emulsion for its production. The person skilled in the art can vary the flowability by means of suitable measures; it is generally increased by increasing the proportion of solvent or increasing the processing temperature. It can also be increased by using polymers with a lower average molecular weight or a lower degree of crosslinking. After applying the adhesive mass, it changes into a non-flowable consistency. This is to be understood to mean that solidification (solidification) takes place, which makes a further change in the shape and position of the threads practically impossible. Such solidification takes place e.g. B. by cooling, by evaporation of the solvent or by crosslinking the polymers.

The intermediate carrier can be a movable base for the adhesive composition that is only used during the manufacturing process, but it is preferably the non-adhesive carrier film. Transport lanes (endless belts, metal foils, protective foils, etc.) can be used as the base used only during the manufacturing process, which are removed again from the adhesive mass in the form of threads in later process steps.

The film-shaped materials known to the person skilled in the art can be used as protective film, for. B. paper, plastics such as polyethylene, silicone, Teflon, Polypropylene, etc. The protective film is preferably abhesive. This means that the side of the protective film which comes into contact with the adhesive composition in the form of threads has been additionally treated in order to make it easier to detach the protective film. For this purpose, the relevant side of the protective film z. B. coated with a very thin layer of silicone.

Area coverage is to be understood as the quotient which corresponds to the area covered with adhesive mass in the form of threads divided by the area enclosed with adhesive mass in the form of threads. A full area

Coating therefore corresponds to a value of 100%. In the case of the adhesive compositions, which are in the form of threads, the area coverage can be ≤ 50% without the function of the adhesive composition suffering significantly. A preferred area occupancy is below 30%, particularly preferably below 20%. A minimum area occupancy of around 2% can be seen.

In addition to the area coverage, the area weight of the adhesive mass is also an indication that enables an estimate of the material savings. Conventional adhesive layers, that is to say obtained by coating or extrusion, have a basis weight of the order of magnitude of 100 g / m ² and above. However, the adhesive strips of the present invention can easily provide adhesive layers whose basis weights are below 100 g / m ² . Even with a basis weight below 30 g / m ² , the desired results are achieved with the adhesive strips of the present invention. In a particularly preferred embodiment, the weight per unit area of the adhesive composition is below 10 g / m ² .

The adhesive strips which can be produced in accordance with the present description have numerous advantages, the considerably less adhesive material being used than the conventionally, ie fully coated, adhesive strips being the most prominent. Nevertheless, the adhesive strips produced by the method presented here can be used for exactly the same purposes in which adhesive strips coated over the entire surface are also used. The method for producing an adhesive composition which is in the form of threads comprises the steps: transferring the adhesive composition to a flowable consistency, allowing the flowable adhesive composition to emerge vertically from at least one outlet nozzle, applying it to a movable base, preferably a non-adhesive backing film, and transferring it to an non-flowable consistency. The method can preferably be carried out continuously. One advantage is that the mechanical parts (outlet nozzle etc.) do not come into contact with the base (carrier film). The method is particularly advantageous if, when the flowable adhesive mass emerges, an air stream exiting from a laterally positioned air outlet slot blows against the adhesive mass before application to the movable base. The flowable adhesive mass is swirled so that the irregular network can finally be formed on the base. The speed of the pad can vary with this method and from low speeds such. B. 0.1 m / s to comparatively high speeds, ie more than 5 m / s range. It is clear that for products in which the requirement for a uniform adhesive layer is less, the production is also possible at very high speeds in the order of 20 to 30 m / s.

A special and surprisingly effective type of use, however, is the use of the adhesive strips according to the invention for catching insects, in particular creeping insects (for example woodlice, beetles, cockroaches, fleas, ants, etc.) Catches of such crawling insects can only have a border (the crawling insects adhere to them immediately after entering the fully coated adhesive surface). Comparative experiments with adhesive strips which have an adhesive mass in the form of threads have shown a significantly higher stock with crawling insects. The reason for this is that these insects are still able to move for a certain time after entering the area enclosed by the adhesive mass and are only held on the surface enclosed in the form of threads of adhesive mass a few “steps” later. With the help of the adhesive composition according to the invention, which is in the form of threads, insect glue can be trapped, as are known to the person skilled in the art from DE 94 06 882 U, WO 97/07673, FR 2 620 304, WO 87/02863 or DE 100 55 135 etc. are produced, only the "full-surface" adhesive surfaces shown there being replaced by an adhesive layer with a smaller surface coverage, as is possible with an adhesive composition which is in the form of threads. In this way an adhesive layer is obtained which instead of a 100% one Area coverage (= full area) has a reduced area coverage, e.g. <50%. However, the adhesive area of such an insect trap with reduced area coverage can also be produced by a non-contact application method, for example by printing the carrier film with the adhesive composition in one special pattern that consists of individual small areas not connected to each other (dots, rhombuses, squares, lines, rectangles, etc.) In this case, the surface coverage of the adhesive layer is to be regarded as the fraction that the actual surface coverage makes up in comparison to a full surface coverage.

Example 1: Production of an adhesive strip with adhesive mass present in the form of threads

A conventional extrusion machine is modified by attaching a molding tool to the ejection zone of the extrusion screw, which has 7 outlet nozzles pointing vertically downwards (circular nozzle opening each 0.5 mm in diameter). A bar with a slot-shaped outlet opening for air is attached somewhat below these outlet nozzles. Air with a low (adjustable) excess pressure can escape from this slot, which laterally meets the adhesive composition which has a flowable consistency and emerges from the outlet nozzles.

The modified extrusion machine is charged with the granulate of a pressure sensitive adhesive (Durotak 1512). At a temperature of 95 ° C, the now flowable adhesive mass emerges from the outlet nozzles. The air flow from the air outlet slot underneath has a pressure of 0.7 bar. A non-adhesive carrier film made of transparent polyester is transported at a speed of 0.5 m / s below the exiting adhesive mass and thereby absorbs the adhesive mass Form of threads on. After these threads have cooled, they are covered with a protective film. Since the adhesive composition was colored with a dye, the structure of the adhesive strip, which is in the form of threads, can be easily recognized, see FIG. 1.

Example 2

Example 1 is repeated under otherwise identical conditions; only the air flow has a pressure of 1.7 bar. An adhesive strip ^ as shown in Fig. 2 is obtained.

Claims

claims

1. adhesive mass, characterized in that it is in the form of threads.

2. Adhesive composition according to claim 1, characterized in that the threads have a thickness of 0.01 to 3 mm.

3. Adhesive composition according to claim 1 or 2, characterized in that the threads have common nodes.

4. Adhesive composition according to one or more of claims 1 to 3, characterized in that it consists of a natural or synthetic polymer.

5. Adhesive composition according to one or more of claims 1 to 4, characterized in that it contains an active ingredient, preferably an insect attractant.

6. Adhesive strip, comprising a non-adhesive carrier film and an adhesive layer thereon, characterized in that the adhesive layer consists of an adhesive in the form of threads.

7. Adhesive strip according to claim 6, characterized in that the threads have a thickness of 0.01 to 3 mm.

8. Adhesive strip according to claim 6 or 7, characterized in that the threads have common nodes.

9. Adhesive strip according to one or more of claims 6 to 8, characterized in that the adhesive composition present in threads contains a natural or synthetic polymer.

10. Adhesive strip according to one or more of claims 6 to 9, characterized in that the surface coverage of the adhesive layer is ≤ 50%, preferably ≤ 30% and particularly preferably ≤ 20%.

11. Adhesive strip according to one or more of claims 6 to 10, characterized in that the weight per unit area of the adhesive layer is below 100 g / m ² , preferably below 30 g / m ² and particularly preferably below 10 g / m ² .

12. Adhesive strip according to one or more of claims 6 to 11, characterized in that the adhesive layer is covered with a protective film.

n

13. Adhesive strip according to one or more of claims 6 to 12, characterized in that the adhesive composition contains at least one active ingredient, preferably an insect attractant.

14. A process for producing an adhesive composition which is in the form of threads, a) converting the adhesive composition into a flowable consistency, b) emerging vertically from at least one outlet nozzle, c) applied to a movable base, preferably a non-adhesive carrier film, and d) is converted into a non-flowable consistency.

15. The method according to claim 14, characterized in that the adhesive mass emerges continuously from the outlet nozzle.

16. The method according to claim 14 or 15, characterized in that between the exit of the adhesive composition from the at least one outlet nozzle and the application on the movable base, air flows against the adhesive composition.

17. The method according to one or more of claims 14 to 16, characterized in that the movable base is transported at a speed of more than 0.1 m / s.

18. Use of an adhesive strip which comprises a carrier film and an adhesive layer, the adhesive layer having an area coverage with adhesive mass ≤ 50% for catching insects.

19. Use according to claim 18, characterized in that the adhesive composition is in the form of threads.