Method for the manufacturing of a polymer product with super- or highly hydrophobic characteristics, a product obtainable from said method and use thereof

Abstract

The present invention relates to a method for manufacturing a polymer product with super- or highly hydrophobic characteristics, preferably in the form of a film. Also methods for the manufacturing of a laminate and a polymer coated paper or board product, respectively, both having said characteristics, are disclosed. The present invention also relates to products obtainable by said methods and uses thereof.

Claims

1. A method for manufacturing a product comprising a polymer coated paper or board, wherein said product has super- or highly hydrophobic characteristics, comprising the following steps: a. providing a melt of polymer and a web of paper or board and coating said web of paper or board directly with said melt of polymer; b. passing said polymer coated web of paper or board over a roll whereby said roll faces the polymer coated side and wherein also said roll provides a mould to produce said product comprising said polymer coated paper or board with a coated side which has a pattern providing a lotus effect, wherein the mould comprises an array of squares or an array of pins; and c. cooling said product obtained.

2. A method according to claim 1 wherein the roll is a cooling drum.

3. A method according to claim 1, wherein the product is a packaging board, wherein the step of providing a web of paper or board comprises providing a board, wherein the board comprises a fibrous board base, and wherein the weight of the polymer coating is at least 14 g/m.sup.2.

4. A method according to claim 3, wherein the density of the fibrous board base is at least 575 kg/m.sup.3.

5. A method according to claim 4, wherein the polymer is selected from the group consisting of polyethylene (PE), polypropylene (PP), ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), a polyester, polylactic acid (PLA), polyamide (PA), and combinations thereof.

6. A method according to claim 3, wherein the density of the fibrous board base is at least 615 kg/m.sup.3.

7. A method according to claim 6 wherein the polymer is PE.

8. A method according to claim 7 wherein also an oleophobic wax is added on to the polymer.

9. A method according to claim 7 wherein oil is added on top of the polymer after moulding.

10. A method according to claim 1, wherein the board comprises a fibrous board base, wherein the density of the fibrous board base is at least 650 kg/m.sup.3, and wherein the weight of the polymer coating is at least 14 g/m.sup.2.

11. A method for manufacturing a product comprising a polymer coated board, wherein said product has super- or highly hydrophobic characteristics, comprising the following steps: a. providing a melt of polymer and a fibrous board base and coating said fibrous board base directly with said melt of polymer, wherein the product is a packaging board and the weight of the polymer coating is at least 14 g/m.sup.2, wherein the density of the fibrous board base is at least 615 kg/m.sup.3 and wherein the polymer is selected from the group consisting of polyethylene (PE), polypropylene (PP), ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), a polyester, polyethylene terephthalate (PET), polylactic acid (PLA), polyamide (PA), and combinations thereof; b. passing said polymer coated board over a roll whereby said roll faces the polymer coated side and wherein also said roll provides a mould to produce said product comprising said polymer coated board with a coated side which has a pattern providing a lotus effect and wherein the roll has a mould comprising an array of squares or an array of pins; and c. cooling said product obtained.

12. A method according to claim 11 wherein also an oleophobic wax is added on to the polymer.

13. A method according to claim 11 wherein oil is added on top of the polymer after moulding.

14. A method according to claim 13 wherein the polymer is PE.

Description

FIGURES

(1) FIG. 1 discloses a material with super- or highly hydrophobic characteristics (thus highlighting the lotus effect).

(2) FIG. 2 discloses hydrophobic liquid package using Metal mould 1.

(3) FIG. 3 discloses hydrophobic liquid package using Metal mould 2.

(4) FIG. 4 discloses hydrophobic liquid package using Metal mould 3: 6 m grooves cross direction, barrell lens f25.

(5) FIG. 5 discloses hydrophobic liquid package using Metal mould 4: 6 m grooves cross direction, barrel lens f12, 7.

(6) FIG. 6 discloses a material with a pattern comprising areas with higher squares.

(7) FIG. 7 discloses a material with a pattern comprising areas with pins.

(8) FIG. 8 discloses a material with a pattern comprising areas with linear bulges.

EXAMPLES

Example 1

(9) Testing: Moulded steel surface was formed with the help of laser The mould was pressed with PE-foil or Cupforma Dairy 2PE 20+255+35 (both encompass LDPEs) to achieve replica pattern on plastic and on liquid package board surface, respectively. Contact angles of liquid and surface were measured for: Water Milk

(10) 4 patterned metal surfaces were pressed with PE-foil or liquid package board to get patterned surfaces

(11) Surfaces 1 and 3 had the highest contact angles as set out below

(12) Contact angels , with water and milk as set out below

(13) TABLE-US-00001 TABLE 1 results from the trials set out above Ref. Surface 1 Surface 2 Surface 3 Surface 4 PE-foil water 83.1 104.6 100.2 96.8 97.7 milk 88.2 80.0 87.3 81.4 71.3 Cupforma Dairy 20 + 255 + 35 water 93.2 139.4 91.7 milk 71.5 71.3 Explanations: Surface 1hydrophobic liquid package using metal mould 1 Surface 2hydrophobic liquid package using metal mould 2 Surface 3hydrophobic liquid package using metal mould 3: 6 m grooves cross direction, barrell lens f25. Surface 4hydrophobic liquid package using metal mould 4: 6 m grooves cross direction, barrel lens f12,7.

(14) Further it could also be detected a positive touch effect as follows. Same samples were creaking or squealing when scratching the surface with a human nail. Just holding the samples gave a touch effect that was nice and pleasant.

Example 2

(15) Three different kinds of super hydrophobic surfaces were formed and top layer of surface was PE. All of surfaces had higher contact angles than 170 which means that drop of water will not stay on surface. It simply runs or floats away. These surfaces were formed with squares, lines and pins (as also reflected by FIGS. 6-8. With squares and pins you could not predict the direction of drop movement. With lines the drop was following the line.

(16) The surfaces were made of PE, in particular an LDPE for liquid packaging hoard. The PE was Borealis CA8200. PE coating of PE-coated board was too thin to get superhydrophobic surface. The testing temperature was 125 C. (to get melted PE). Tests were then done with PE-foil9 layers of foil were put on each other and this stack was pressed with mould (form). A few PE-layers (bottom side) was replaced with PE-coated liquid packaging board and mould was on top. This stack was also pressed with mould. Mould and PE was heated and pressed together to copy the form to PE surface.

(17) The surface metal mould was formed with laser as a replica (pattern). Thre different patterns were made and all three surfaces were superhydrophobic. Their contact angle with water drop was over 170. It was difficult to add a drop on surface, it did not fix to the surface. If managing to spill a drop on the surface it rolled away.

(18) Further the surface with lines had a special character. The drops rolled away at line direction. FIG. 6 reflects the pattern comprising areas with higher squares. FIG. 7 reflects the pattern comprising areas with pins. FIG. 8 reflects the pattern comprising areas with linear bulges. Said figures depict, as mentioned, three different superhydrophobic PE surfaces.

(19) Various embodiments of the present invention have been described above but a person skilled in the art realizes further minor alterations, which would fall into the scope of the present invention. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. For example, any of the above-noted methods may be combined with other known methods. Other aspects, advantages and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.