Diecut, in particular for permanently closing holes

Abstract

Diecuts are configured for permanent closing of holes and have a carrier comprising an assembly of at least two polymeric films. An upper film of the at least two polymeric films has a basis weight of at least 1.0 kg/m.sup.2 and a lower film of the at least two polymeric films consisting of at least two layers, wherein a first layer is in the form of a polymeric film and faces the upper film, and a second layer is in the form of a functional layer with a side of the lower film, facing away from the upper film, bears an applied adhesive composition.

Claims

1. A diecut configured for permanent closing of at least one hole, the diecut comprising: a carrier comprising an assembly of at least two polymeric films, wherein the at least two polymeric films comprise an upper film and a lower film, the upper film having a basis weight of at least 1.0 kg/m.sup.2 and the lower film consisting of at least two layers, the at least two layers of the lower film have a first layer in the form of a polymeric film facing the upper film and a second layer in the form of a functional layer, a side of the lower film facing away from the upper film has an applied adhesive composition the functional layer has a first barrier effect with respect to first migratable substances that are diffusible into the applied adhesive composition and a second barrier effect with respect to second migratable substances that are diffusible into the upper film, the first migratable substances comprise one or more oils, one or more lubricants, and one or more plasticizers, the second migratable substances comprise one or more tackifier resins, and a melting point of a polymer of the functional layer is above a melting point of a polymer of the upper film by 20 C.

2. The diecut according to claim 1, wherein the upper film of the at least two polymeric films and the polymeric film and the functional layer of the lower film are each implemented over the full area and are free from holes or vacancies.

3. The diecut according to claim 1, wherein the upper film has a basis weight of between 1.0 and 6 kg/m.sup.2.

4. The diecut according to claim 3, wherein the upper film has a basis weight of between 1.5 and 3.9 kg/m.sup.2.

5. The diecut according to claim 4, wherein the upper film has a basis weight of between 1.5 and 2.5 kg/m.sup.2.

6. The diecut according to claim 1, wherein the upper film is an elastomer-modified bitumen film.

7. The diecut according to claim 1, wherein the upper film is a polyolefin film.

8. The diecut according to claim 7, wherein the upper film is a polyethylene and ethylene-vinyl acetate film.

9. The diecut according to claim 8, wherein the polyethylene and ethylene-vinyl acetate film is mineral-filled.

10. The diecut according to claim 1, wherein the polymeric film of the lower film consists of a type of polymer used in the upper film.

11. The diecut according to claim 1, wherein the polymeric film of the lower film consists of polyolefin.

12. The diecut according to claim 11, wherein the polymeric film of the lower film consists of polyethylene.

13. The diecut according to claim 1, wherein the melting point of the polymer of functional layer is above the melting point of the polymer of the upper film by 50 C.

14. The diecut according to claim 1, wherein the polymer of the functional layer comprises one or more selected from the group consisting of polyethylene terephthalate, polyamide, polyurethane, polyoxymethylene, polyvinyl chloride, polyethylene napthalate, ethylene-vinyl alcohol, polyvinylidene chloride, polyvinylidene fluoride, polyacrylonitrile, polycarbonate, polyethersulfone, polyimide, polyarylene sulfide, polyarylene oxide, and mixtures thereof.

15. The diecut according to claim 14, wherein the polymeric film of the lower film consists of polyethylene and polymer of the functional layer consists of polyamide.

16. The diecut according to claim 1, wherein the thickness of the upper film is between 400 and 3500 m and the thickness of the lower film is between 25 and 200 m.

17. The diecut according to claim 1, wherein the applied adhesive composition is an acrylate-based self-adhesive composition.

18. A vehicle body comprising: at least one hole to be closed; and the diecut according to claim 1 applied over and closing the at least one hole.

19. The diecut according to claim 18, wherein the diecut is applied concentrically over the at least one hole.

20. The diecut according to claim 19, wherein contours of the diecut correspond to the contour of the at least one hole such that a margin of overlap is between 1 and 20 mm.

Description

(1) Below, on the basis of a figure, the diecut for the permanent closing of holes especially in metal sheets or in plastics parts of automobile bodies is to be elucidated in more detail, without any intention of a restrictive effect in any form.

(2) FIG. 1 shows a hole in a body that is to be closed, and also the state after closure of the hole that was to be closed.

(3) FIG. 2 is a graph showing the relation between heat flow along the y-axis and temperature along the x-axis for evaluating glass transition temperature.

(4) The body 5 contains, as a result of its construction, a hole 6, which is to be closed.

(5) For this purpose, a diecut 1 with a carrier composed of a laminate of at least two polymeric films, namely an upper film 2 and a lower film 3, the upper film 2 having a basis weight of at least 1.0 kg/m.sup.2, and a pressure-sensitive adhesive 4 is fixed on the hole 6 in such a way that the hole 6 is covered fully by the diecut.

(6) The lower film 3 consists of two layers, a polymeric film 3a and a functional layer 3b, which has barrier properties.

(7) The area of the diecut 1 is greater than the area of the hole 6 to be closed, and so the hole 6 is closed over its full area.

(8) In the text below, the invention is elucidated in more detail by a number of examples, without wishing thereby to restrict the invention.

INVENTIVE EXAMPLE

(9) The carrier of the diecut of the invention consists of an assembly of two polymeric films.

(10) The composition of the upper film is as follows:

(11) TABLE-US-00002 40 wt % CaCO.sub.3 as filler 30 wt % Polyethylene 10 wt % EVA 20 wt % Oil

(12) The thickness of the film is 2000 m, and the basis weight is 2.5 kg/m.sup.2.

(13) The lower film of the two polymeric films consists of at least two layers, a first layer in the form of a polyethylene film, which faces the heavy-duty film, and a second layer in the form of a functional layer of polyamide.

(14) The thickness of the polymeric film is 70 m, and the thickness of the functional layer is 20 m.

(15) As adhesive, a customary acrylate-based pressure-sensitive adhesive is coated at 80 m onto the carrier.

(16) Test results:

(17) TABLE-US-00003 Peel adhesion, steel, fresh 13 N/cm Peel adhesion, steel, after one month 40 C. 12 N/cm

COMPARATIVE EXAMPLE

(18) The composition of the film is the same as that of the heavy-duty film:

(19) TABLE-US-00004 40 wt % CaCO.sub.3 as filler 30 wt % Polyethylene 10 wt % EVA 20 wt % Oil

(20) In this case there is no lower film with barrier layer effect between the heavy-duty film and the adhesive.

(21) The adhesive and also the applied weight are the same as those used in the inventive example.

(22) TABLE-US-00005 Peel adhesion, steel, fresh 10 N/cm Peel adhesion, steel, after one month 40 C. 2 to 4 N/cm

(23) The peel adhesions measured in the inventive and comparative examples immediately after bonding are virtually the same.

(24) Conversely, after storage of one month at 40 C., the peel adhesion of the comparative example is much lower than the peel adhesion of the inventive example.

(25) The reason for this is that in the comparative example, oil has migrated from the heavy-duty film into the adhesive and/or, in the opposite direction, tackifier resin has migrated from the adhesive into the heavy-duty film. Both effects lead to a reduction in the bond strength.

(26) In the inventive example, in contrast, these migrations are prevented by the lower film, which comprises a first layer in the form of a polyethylene film and a second layer in the form of a functional layer of polyamide.