Method for coating a hollow container comprising molded pulp

Inventors: Lars Sandberg (Hammarö, SE); Yselaure Boissard (Örebro, SE); Shoko Yamada (Vintrie, SE); Andreas Nyström (Karlstad, SE); Christopher T. Karlsson (Hammarö, SE)

Assignee: ALPLA WERKE ALWIN LEHNER GMBH & CO KG

D21J1/08 B65D1/0215 B65D23/02 B65D23/0821 B65D65/42 D21H19/22 D21H19/84 D21H21/16 D21H23/50 D21H23/72 D21J3/10 B65D2565/387

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Quick Facts

Patent No.: US 12674284
App. No.: 18/551,924
Filed: Sep 22, 2023
Granted: Jul 7, 2026
Kind: B2
Examiner: HOPPMANN, JOHN MARTIN
Art Unit: 3733
USPC: 215/12.2

External Links

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Abstract

The present disclosure generally relates to a method for providing a barrier coating on a hollow container ( 100 ) comprising molded pulp. The method comprises providing a polymeric powder coating onto the interior surface ( 105 a ) and at least a portion of the exterior surface of the container ( 100 ) prior to curing and/or melting the powder coatings. The present disclosure also relates to a hollow container ( 100 ) formed by the method.

Claims (19)

1 . A method for providing a barrier coating on a hollow container ( 100 ) comprising molded pulp; said method comprising:

a) providing a hollow container ( 100 ) comprising molded pulp, wherein said hollow container ( 100 ) comprises a main portion ( 101 ) and an upper portion ( 102 ); said hollow container extending along a longitudinal center line ( 103 ), wherein the longitudinal extension of said upper portion ( 102 ) corresponds to 5-30% of the maximum longitudinal extension of said hollow container ( 100 ), and wherein the longitudinal extension of said main portion ( 101 ) corresponds to 70-95% of the maximum longitudinal extension of said hollow container ( 100 ), wherein said hollow container comprises a bottom surface ( 104 ) and sidewalls ( 105 ) extending from said bottom surface ( 104 ) to an opening ( 106 ) of said hollow container; said sidewalls ( 105 ) and said bottom surface ( 104 ) defining an exterior surface and an interior surface ( 105 a ) of said hollow container;

b) depositing a polymeric powder onto the interior surface ( 105 a ) of said hollow container ( 100 ) by means of a spraying device ( 107 ) capable of charging the polymeric powder prior to or during deposition of said polymeric powder, wherein at least said main portion ( 101 ) of said hollow container ( 100 ) is grounded during said polymeric powder deposition, wherein said polymeric powder deposition step b) is carried out in a molding device ( 108 ) comprising an electrically conductive material, and wherein said molding device ( 108 ) comprises at least a first ( 108 a ) and a second ( 108 b ) removable portion, wherein said first removable portion ( 108 a ) is configured to enclose said upper portion ( 102 ) of said hollow container ( 100 ) and wherein said second removable portion ( 108 b ) is configured to enclose said main portion ( 101 ) of said hollow container ( 100 );

c) depositing a polymeric powder onto the exterior surface of at least a portion of said upper portion ( 102 ) of said hollow container ( 100 ) by means of said spraying device ( 107 ), wherein the exterior surface of said main portion ( 101 ) is void of a barrier coating comprising polymeric powder, wherein said polymeric powder deposition step c) is performed by arranging said spraying device ( 107 ) at a distance, d 1 , of from 10 mm to 250 mm from said opening ( 106 ) of said container, wherein said first removable portion ( 108 a ) is removed from said molding device ( 108 ) during said polymeric powder deposition step c); and

d) treating said hollow container with heat or irradiation under conditions that melt and/or cure said polymeric powder after said steps b) and c).

2 . The method according to claim 1 , wherein said hollow container has a moisture content of from 3 to 15% during said steps of polymeric powder deposition.

3 . The method according to claim 1 , wherein said molding device comprises a formable electrically conductive material.

4 . The method according to claim 1 , further comprising the step of:

a′) conditioning the hollow container at an ambient relative humidity of from 30 to 100%, after step a) of providing said hollow container comprising molded pulp.

5 . The method according to claim 1 , wherein said polymeric powder deposition steps b) and c) are performed simultaneously.

6 . The method according to claim 1 , wherein said hollow container is a bottle, wherein said upper portion ( 102 ) comprises a shoulder portion ( 102 a ) and a neck portion ( 102 b ), wherein said neck portion has a smaller cross-sectional area than said main portion and is configured to circumferent at least said opening ( 106 ) of said bottle, and wherein said shoulder portion ( 102 a ) is arranged to taper between said main portion ( 101 ) and said neck portion ( 102 b ).

7 . The method according to claim 6 , wherein at least said neck portion ( 102 b ) of said upper portion ( 102 ) is coated in said polymeric powder deposition step c).

8 . The method according to claim 6 , wherein the entire upper portion ( 102 ) of said hollow container ( 100 ) is coated in said polymeric powder deposition step c).

9 . The method according to claim 1 , wherein said step d) is performed by heating said hollow container ( 100 ) at a temperature of from 120° C. to 220° C., for 1 to 30 minutes.

10 . A hollow container ( 100 ) formed by the method according to claim 1 , wherein the hollow container comprises a main portion ( 101 ) and an upper portion ( 102 ); said hollow container extending along a longitudinal center line ( 103 ), wherein the longitudinal extension of said upper portion ( 102 ) corresponds to 5-30% of the maximum longitudinal extension of said hollow container ( 100 ), and wherein the longitudinal extension of said main portion ( 101 ) corresponds to 70-95% of the maximum longitudinal extension of said hollow container ( 100 ), wherein said hollow container comprises a bottom surface ( 104 ) and sidewalls ( 105 ) extending from said bottom surface ( 104 ) to an opening ( 106 ) of said hollow container; said sidewalls ( 105 ) and said bottom surface ( 104 ) defining an exterior surface and an interior surface ( 105 a ) of said hollow container, wherein said hollow container comprises a barrier coating comprising polymeric powder on said interior surface ( 105 a ) of said hollow container and on the exterior surface of at least a portion of said upper portion ( 102 ) of said hollow container, wherein the exterior surface of said main portion ( 101 ) is void of a barrier coating comprising polymeric powder.

11 . A hollow container according to claim 10 , wherein said hollow container is a bottle; said upper portion ( 102 ) comprising a shoulder portion ( 102 a ) and a neck portion ( 102 b ), wherein said neck portion has a smaller cross-sectional area than said main portion and is configured to circumferent at least said opening ( 106 ) of said bottle, and wherein said shoulder portion is arranged to taper between said main portion and said neck portion, wherein said bottle comprises a barrier coating comprising polymeric powder on the interior surface ( 105 a ) of said bottle and on at least the exterior surface of said neck portion ( 102 b ) of said bottle.

12 . A hollow container according to claim 10 , wherein the thickness of the barrier coating is in the range of from 5 to 300 μm.

13 . The method according to claim 4 , wherein said step a′) comprises conditioning the hollow container at an ambient relative humidity of from 60 to 100% after step a) of providing said hollow container comprising molded pulp.

14 . The container according to claim 12 , wherein the thickness of the barrier coating is in the range of from 20 to 100 μm.