Method for molding a body in a mold

Abstract

Method for molding a body in a mold, comprising the following steps: applying an adhesive tape to the inside of a mold, distributing the layers of material forming the body over the adhesive tape, curing the layers of material, removing the body from the mold, where the adhesive tape has a backing on one side of which a self-adhesive has been applied in the form of a polymer mixture, the polymers being constructed of 60 to 99.5 wt % of n-butyl acrylate and/or 2-ethylhexyl acrylate, 0.5 to 10 wt % of an ethylenically unsaturated monomer having an acid or acid-anhydride function, 0 to 30 wt % of one or more olefinic monomers and the self-adhesive comprises between 0 and 60 parts by weight of one or more tackifiers.

Claims

1. Method for molding a body in a mold, comprising the following steps: application of an adhesive tape to the inside of a mold, distribution of the material layers forming the body on the adhesive tape, curing the material layers, and removal of the body from the mold, wherein the adhesive tape has a carrier film, on one side of which a self-adhesive compound is applied in the form of a polymer mixture, wherein the polymers are composed of the following: (a) 60 to 99.5 wt. % of n-butyl acrylate and/or 2-ethylhexyl acrylate, (b) 0.5 to 10 wt. % of an ethylenically unsaturated monomer with an acid or acid anhydride functional group, and (c) 0 to 30 wt. % of one or a plurality of (a) various olefin monomers, and the self-adhesive compound contains 0 to 60 parts by weight of one or a plurality of tackifiers based on the mass of the polymer mixture.

2. Method according to claim 1, wherein (a) comprises a mixture of 2-ethylhexyl acrylate and n-butyl acrylate.

3. Method according to claim 1, wherein monomer (b) is acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and/or maleic acid anhydride.

4. Method according to claim 1, wherein the monomers (c) are selected from the group consisting of alkyl(meth)acrylates, other than the monomers forming (a), C.sub.1 to C.sub.10 hydroxyalkyl(meth)acrylates, and unsaturated hydrocarbons with 2 to 8 carbon atoms.

5. Method according to claim 1, wherein the polymers are composed of a) 75 to 94 wt. % of n-butyl acrylate and/or 2-ethylhexyl acrylate, b) 1 to 5 wt. % of an ethylenically unsaturated monomer with an acid or acid anhydride functional group, and c) 5 to 20 wt. % of one different olefin monomer or a plurality of different olefin monomers.

6. Method according to claim 1, wherein the polymers are composed of a) 87 to 94 wt. % of n-butyl acrylate and/or 2-ethylhexyl acrylate, b) 1 to 3 wt. % of an ethylenically unsaturated monomer with an acid or acid anhydride functional group, and c) 5 to 10 wt. % of one or a plurality of (a) different olefin monomers.

7. Method according to claim 1, wherein the self-adhesive compound contains 15 to 50 parts by weight of one or a plurality of tackifiers based on the mass of the polymer mixture.

8. Method according to claim 1, wherein films composed of PUR, PE, PP, PET or PA are used as carrier films.

9. Method according to claim 1, wherein the carrier film contains one or at least two fluoropolymers.

10. Method according to claim 9, wherein the carrier film contains up to 50 wt. % of one or at least two fluoropolymers based on the total composition of the carrier film or the polymers making up the carrier film are composed up to 100% of one or at least two fluoropolymers.

11. Method according to claim 9, wherein as fluoropolymers, PTFE (polytetrafluoroethylene), ETFE (poly(ethylene-co-tetrafluoroethylene)), FEP (poly(tetrafluoroethylene-co-hexafluoropropylene)), PVF (polyvinyl fluoride), PCTFE (polychlorotrifluoroethylene), ECTFE (poly(ethylene-co-chlorotrifluoroethylene), PVDF (poly(1,1-difluorethene)), PFA (perfluoroalkoxy polymers), or mixtures of two or more of the aforementioned fluoropolymers are used.

12. Method according to claim 11, wherein the fluoropolymers are mixed with further polymers.

13. Method according to claim 1, wherein the thickness of the carrier film is 15 to 350 m.

14. Method according to claim 1, wherein the carrier film is composed of an at least two-layered laminate comprising two or more film layers.

15. Method according to claim 1, wherein the carrier film is composed of at least two film layers, wherein the two outer film layers are of different colors.

16. Method according to claim 1, wherein the mass of the adhesive compound applied to the carrier film is 10 to 200 g/m.sup.2.

17. Method according to claim 1, wherein the inside of the mold is equipped with a release agent before application of the adhesive tape.

18. Method according to claim 1, wherein curing of the material layers is carried out in a vacuum.

19. Method according to claim 3, wherein monomer b is acrylic acid, methacrylic acid or a mixture thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the arrangement of the individual layers in the mold in a side view,

(2) FIG. 2 shows the arrangement of the individual layers in the mold from above, and

(3) FIG. 3 shows a simplified detail section of FIG. 1.

(4) The arrangement of the individual layers in the mold is shown in a side view in FIG. 1 and from above in FIG. 2.

(5) The mold 4 is equipped with an extremely thin layer measuring only few m in thickness of a release agent 6, for example a solvent-based suspension of low-molecular weight PTFE, whose thickness is not shown in FIG. 1 in the correct proportions. Application is carried out using a cloth. The suspension then dries, resulting in an extremely thin film. After this, the adhesive tape 1 is applied in one layer to the inside of the mold 4.

(6) FIG. 3 shows that the edges of the individual strips of the adhesive tape 1, 2, 3 are placed adjacent to one another, thus not showing any intervals. The individual adhesive tape sections 1, 2, 3 are composed of a carrier film 10 to which an adhesive layer 11 is applied.

(7) After bonding of the adhesive tape 1, the material layers forming the body 5 are distributed over the adhesive tape.

(8) After this, a sealing film 21 is fixed over the material 5 by means of a second adhesive tape 24 in such a way that a sealed space is produced.

(9) In FIG. 2, only half of the protective film 21 is shown. The protective film 21 is fixed on the mold 4 by the second adhesive tape 24.

(10) The air is removed via an outlet 22. The resin is supplied to the material layers 5 via an inlet 23 until they are saturated.

(11) This is followed by the curing process.

(12) When said process is completed, the sealing film 21 is removed, and the finished formed pieces can be removed from the mold 4.