DE4337116A1 - Tubular plastic film, its use and process for its manufacture - Google Patents

Description

The invention relates to a tubular plastic film, its Use and a process for their manufacture. The invent This tubular film is intended to be preferred wise round, usually two-part objects, adherent to enclose so that the circumferential gap between the at the parts are permanently covered by this enclosure.

An important area of application of the invention are so-called origi Quality closures of halves with screw closures bottles or similar containers. Through this arrested Encapsulation or sealing is the intact Origi Bottling guaranteed as long as the closure is undamaged is. The backup method is used in many different areas distribution of rivers filled in bottles or containers liquids, powders, granules for the most varied Ingredients used.

So far, mainly as a material for the production of such shrinkable locking fuses polyvinyl chloride (PVC) set. However, this material has considerable disposal Disadvantages as it burns very badly and hydrogen chloride arises.  

In contrast, the combustion of polyolefins only carbon dioxide and water.

Poly can also be used as further sealing materials ester or polystyrene can be used.

The previous efforts, especially for environmental reasons to replace the PVC. e.g. B. by a polyolefin such as polyethylene (PE), because of the high elasticity of the material and because of the insufficient adhesion to the load to be secured do not hold to success.

In order to overcome these difficulties, the invention lies the thought is based. PE in combination with several other substances as the starting material for the tubular Use plastic film. As has been shown, by a tubular film made of a cross-linked PE each essentially round object strongly enclosed the adhesive forces between the object and the surrounding tubular film are larger than the Festig perforation if the tubular film has passed through Heat has been caused to shrink.

Based on these findings, the first subject of the Invention a tubular extrusion Plastic film with a thickness between 0.05 and 0.7 mm and a diameter of about 2 to 100 mm, which for thermal Shrinkage is made up of

• a. Cross-linked polyethylene (X-PE) as the base polymer and under Bei mix of  
• b. Proportions of one or more tensile reducing agents Fillers,
• c. Proportions of at least one polar olefinic Co polymer,
• d. Shares of at least one cling agent,
• e. Proportions of different stabilizers.

The shares in cross-linked polyethylene and in the individual Zu Impact materials vary because they are due to the a thin gap separated and to be enclosed are usually about different materials, each with different surface properties. The adhesive force the film depends heavily on the respective material and its Surface, and it will be from the combination of the supplement substances significantly affected. Therefore - also because of the ver different materials between the two to be enclosed Split - the proportions of these aggregates only in certain Limit ranges can be specified.

Therefore, it is further suggested that the share of networked Polyethylene between 5 and max. Is 50% and that tensile reducing fillers individually or in a mixture of several Substances with a total content of 10 to 50% are added. When Fillers are suitable for chalk and / or kaolin and / or talc and / or mica and / or starch. It also has proven to be proved in part that the proportion of polar olefinic Co polymer is 10 to 60% and that the polar olefinic Copolymers an ethylene / vinyl acetate and / or a sodium or Zinc ionomers are.  

The proportion of cling agents that is between min. 3% and max. 40% and preferably based on a polyisobu tylen or should have an atactic polypropylene. Except it is proposed that a mixture of stabilizers Antioxidants / anti-aging agents, a UV stabilizer, a thermal stabilizer, a metal deactivator and / or a Processing agents in the recommended concentration of each 0.1 to about 2% is used. If necessary, it is easily possible Lich that the compound components except the polyethylene so probably as pure components as well as a batch in a polymer are added, the compound being a color concentrate as a pig ment or as a batch.

Another object of the invention is in the usability the tubular plastic film according to the invention with the seen above features, which is that section te of the tubular film for firmly enclosing essentially round one or more parts or a umlau objects that have a gap due to heat effect achievable narrowing of the hose width can be used and further in that the tubular film from a only slightly larger internal dimensions than the largest external dimensions of one or more parts, or a circumferential gap object put on this and then to educate exposing the shrinking process to heat treatment becomes.

Of particular importance is the type and Intensity as well as the duration of the heat treatment that between Can be 1 and 10 s. For heat treatment, different heat sources or heat generators are used. The heating can take place in that the heat treatment  by all-round hot air flow or by all-round loading steaming is going on, or the heat treatment can go through inductive or capacitive heating.

Furthermore, the heat treatment can also be carried out by an infrared or the like. Heat radiation or also through direct heat transfer from an object to be enclosed with the film form-fitting surrounding heat-emitting solid, the multi-part solid body in its inner contour after the The outer contour of the surrounding object is shaped is.

In addition, the invention also includes the process for the manufacture position of the tubular plastic film according to the invention, and this consists of the steps

• 1. Extrude the tubing from the compound components as Powder and / or granules,
• 2. cross-linking of the extruded tube,
• 3. Expand to the intended internal dimension and freeze the thus obtained form.

Other procedural features are that the the gel content to be observed for crosslinking min. 40% to max. 75% and a thermal expansion behavior (hot set) between 200% to 450% is observed.

The latter process step is therefore for use Availability and functionality of the film of crucial Significance because of the hot set / gel content the degree of cross-linking we is significantly dependent and thereby affects the adhesive force becomes.  

Another object of the invention relates to an abge changed process for the production of the adherent enclosure ß serving tubular plastic film sections in the following way that the tubular extruded / ex panded continuous film plastic film at intervals from each other with a per. arranged on a line or in a zone forcing and into the sections created by it divided, then into theirs to slip over the one to be enclosed The intended form of provision brought who the. The perforation makes it easy to separate the end los plastic film in application-specific film sections enough.

Another additional subject of the invention relates to a closure arrangement of essentially one or more parts or objects with a circumferential gap, in particular openings with screw or similar closures see containers, through a firmly adhering enclosure through sections of a tubular plastic film with the Features of claims 1 to 11, with one in a zonal area richly distributed perforation. The sticky order Closure is applied to the plastic film when force is applied Tear perforation first. This is the original closure for clearly destroyed the viewer as a sign of that the originality and integrity of the content is no longer guaranteed.

The invention is explained in an exemplary embodiment with reference to a drawing. The drawing shows, as Fig. 1, the upper closure area of a bottle, which is shown in the middle and is described in more detail below.

The tubular plastic film 3 is placed over the upper closure area of the bottle 1 with a screw cap 2 , so that the circumferential gap 5 between the screw cap 2 and the bottle neck is permanently covered. The tubular plastic film 3 consists of a mixture of 5 to 50% cross-linked polyethylene, to which variable proportions of filler-reducing fillers between 10 and 50% are also added. Chalk and / or kaolin and / or talc and / or mica and / or starch can be used as fillers. It also contains a proportion of between 10 and 60% of polar olefinic copolymers in the form of ethylene / vinyl acetate and / or as sodium or zinc ionomer. The addition of cling agent, which can be a polyisobutylene or an atactic polypropylene, is between 3 and 40%. As a stabilizer in a proportion of 0.1 to 2% each, a mixture of antioxidants / anti-aging agents, a UV stabilizer, a thermal stabilizer, a metal deactivator and / or a processing aid is added to the compound. In order to achieve easier miscibility, the compound constituents can be added in addition to the polyethylene as pure components or as a batch, where the compound can also contain a color concentrate as a pigment or as a batch. The individual material components are coordinated depending on the type of material or materials to be enclosed. The adhesiveness of the plastic film 3 is strongly dependent on the surface condition of the object enclosed by it.

An additional subject of the invention consists in the use of the tubular plastic film 3 in that sections thereof, in particular round objects, such as the closure region of the bottle 1 shown in FIG. 1 , are firmly enclosed. The inner dimension of the plastic film 3 may only be slightly larger than the largest outer dimension of the closure region to be enclosed by the same when the cover 1 is put on the bottle 1 . The adhesion of the plastic film 3 was achieved by the action of heat. The resulting shrinkage process causes a narrowing of the hose width and thus a tight fit of the plastic film 3rd The action of heat on the plastic film 3 can be done either by a uniform flow of hot air or steaming the same or by inductive or capacitive heating. Heat irradiation also proves advantageous, e.g. B. by infrared radiators. An immediate optimal heat transfer is achieved when the closure area of the bottle 1 enclosed by the plastic film 3 is already heat-giving. It should be ensured that the respective solid body, in the present example the bottle 1 , is formed in the inner contour according to the outer contour of the object to be enclosed in order to avoid thermal stresses. The plastic hose 3 according to the Invention can be used for objects and containers with a wide variety of contents such. B. for food, pharmaceuticals, cosmetics, chemicals, etc. for permanent coverage and to protect against misuse can be used ver. But it can also be used to isolate capacitors and batteries, for example, the latter also being protected against leakage.

Another object of the invention includes the process for the manufacture of the tubular plastic film shown in Fig. 1. Then the plastic tube 3 is extruded in a first process step, whereupon the same is subsequently crosslinked. The higher the degree of crosslinking of the polyethylene, the more the components of the compound mixture are influenced. The degree of crosslinking can be indicated on the one hand by the gel content. In order to obtain an adequate shape memory of the polyethylene, it is chosen between 40 and 75%. Another measure of the degree of crosslinking is the thermal expansion behavior - hot set - of the material; it is chosen between about 200 to 450%. Exact compliance with the mixing ratios and process steps specified according to the invention must be observed. In a last procedural step, the expansion or expansion of the plastic hose 3 to the intended internal dimension and a subsequent freezing of the shape obtained by sudden cooling takes place.

After a modification of the method for producing the adherent enclosing tubular sections of the plastic film 3 , the tubular extruded and then expanded continuous plastic film is provided with perforations at intervals, which can be arranged on a line or in a selected zone. By separating the endless plastic film at these marked points, individual sections are formed which, in accordance with the intended object, such as the closure region of the bottle 1 shown in FIG .

Another additional arrangement according to the invention relates to the closure arrangement of single-part or multi-part objects or having a gap; an example relating to the closure region of the bottle 1 shown in FIG. 1. The upper closure area of the bottle 1 is firmly enclosed by the plastic film 3 , so that in this way the gap 5 between the bottle closure and the bottle neck is sealed and thus guarantees the originality of the bottle contents. Sloping from the lower edge of the plastic film 3 to the gap 5 between the bottle stopper and bottle neck, the plastic film 3 has a perforation 4 . When the bottle cap is turned, the plastic film 3 tears at this perforation, the parts of the plastic film 3 still being able to adhere to the bottle neck due to the adhesive forces. By destroying the plastic film 3 , a visible original filling is no longer guaranteed.

Claims (23)

1. Tubular plastic film with a thickness between 0.05 and 0.7 mm and a diameter between 2 and 100 mm, which is produced by extrusion and is suitable for thermal shrinking, consisting of

• 1a. Cross-linked polyethylene (X-PE) as the base polymer and with the addition of
• 1b. Proportions of one or more tensile strength reducing the fillers,
• 1c. Proportions of at least one polar olefinic copolymer.
• 1d. Shares at least one cling agent.
• 1e. Proportions of different stabilizers.

2. Plastic film according to claim 1, characterized in that the proportion of cross-linked polyethylene be between 5 and 50% wearing. 3. Plastic film according to claim 1, characterized in that tensile strength reducing fillers individually or in one Ge Mix several substances with a total share of 10 to 50% are set. 4. Plastic film according to claim 3, characterized in that as fillers chalk and / or kaolin and / or talcum and / or mica and / or starch are suitable. 5. Plastic film according to claim 1, characterized in that the proportion of polar olefinic copolymers 10 to 60% is. 6. Plastic film according to claim 1, characterized in that the polar olefinic copolymers are an ethylene / vinyl acetate and / or are a sodium or zinc ionomer. 7. Plastic film according to claim 1, characterized in that the share of the cling agent between 3 and max. Is 40%. 8. Plastic film according to claim 7, characterized in that the cling agent is preferably a polyisobutylene or a is atactic polypropylene. 9. Plastic film according to claim 1, characterized in that a mixture of antioxidants / aging as stabilizers protective agents, a UV stabilizer, a thermal stabilizer, a metal deactivator and / or a processing aid in the recommended concentration of 0.1 to about 2% each serves.   10. Plastic film according to claim 1, characterized in that the compound components except the polyethylene so probably as pure components as well as a batch in a polymer be added. 11. Plastic film according to claim 1, characterized in that the compound is a color concentrate as a pigment or as a batch contains. 12. Use of the tubular plastic film after a little at least one of claims 1 to 11, characterized in that that sections of the tubular film for adhering order close essentially round one or more parts or a circumferential gap objects by un The narrowing of the hose width achievable under the effect of heat are reversible. 13. Use according to claim 12, characterized in that the tubular film from a slightly larger one Inner dimension as the largest outer dimension of one or more part, or having an all-round gap put this on and then to achieve the shrinking process it is exposed to heat treatment. 14. Use according to claim 12, characterized in that heat treatment by all-round hot air flow he follows. 15. Use according to claim 12, characterized in that the heat treatment is carried out by vapor deposition on all sides.   16. Use according to claim 12, characterized in that heat treatment by inductive or capacitive heating mung takes place. 17. Use according to claim 12, characterized in that the heat treatment by an infrared or the like radiation occurs. 18. Use according to claim 12, characterized in that the heat treatment by direct heat transfer from form the object to be enclosed with the film conclusive surrounding heat-emitting solid takes place. 19. Use according to claim 12 and 18, characterized in that the multi-part solid body in its inner contour the outer contour of the surrounding object is formed is. 20. A method for producing the tubular plastic film, characterized by

• 1. Extruding the tube from the compound stock parts as powder and / or granules,
• 2. cross-linking of the extruded tube,
• 3. Expand to the intended internal dimension and freeze the shape thus obtained.

21. The method according to claim 20, characterized in that the gel content to be observed during crosslinking min. 40% up to max. 75% and a thermal expansion behavior (hotset) between 200% up to 450% is observed.   22. A method of making an adherent enclosure serving tubular plastic film sections because characterized in that the tubular extruded / ex panded endless plastic film at intervals from each other a perforation arranged on a line or in a zone tion and into the sections created thereby divides, then into their to put on the Ge to be enclosed the intended form of provision brought and by Heat effect can be shrunk. 23. Closure arrangement of essentially one or more parts objects or objects with a circumferential gap, in particular openings with screw or similar closures provided containers, characterized by a firmly adhering Enclosed by sections of a tubular art Stoffolie with the features of claims 1 to 11, with perforation distributed in a zone area.