Method of making packaging material

• US 7,341,643 B2
• Filed: 11/06/2003
• Issued: 03/11/2008
• Est. Priority Date: 02/07/2001
• Status: Expired due to Term

• Current Assignee: Sonoco Development Inc (Sonoco Products Company)
• Original Assignee: Sonoco Development Inc (Sonoco Products Company)
• Inventors: Huffer, Scott W., Schuetz, Jeffrey M.
• Primary Examiner(s): Tucker; Philip
• Assistant Examiner(s): Chan; Sing P.
• Application Number:
  US10/702,980
• Publication Number:
  US 20040094267A1
• Time in Patent Office: 1,587 Days
• Field of Search: 156/277, 156/278, 156/289, 427/207.1, 427/208, 427/208.4, 427/372.2, 427/402, 427/407.1, 427/372, 428/34.1, 428/34.3, 428/35.2, 428/35.4, 428/35.5, 428 357- 359, 428/41.8
• US Class Current: 156/278
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B65D 65/14 with areas coated with adhesive
• CPC Class Codes: Y10T 428/1334 Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
• CPC Class Codes: Y10T 428/1379 Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
• CPC Class Codes: Y10T 428/1383 Vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit is sandwiched between layers [continuous layer]
• CPC Class Codes: Y10T 428/1386 Natural or synthetic rubber or rubber-like compound containing
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/24777 Edge feature
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/2809 including irradiated or wave energy treated component
• CPC Class Codes: Y10T 428/287 including epoxy group or epoxy polymer
• CPC Class Codes: Y10T 428/2883 including addition polymer of diene monomer [e.g., SBR, SIS, etc.]
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31826 Of natural rubber
• CPC Class Codes: Y10T 428/31837 Including polyene monomers
• CPC Class Codes: Y10T 428/31841 Next to cellulosic
• CPC Class Codes: Y10T 428/31917 Next to polyene polymer

Abstract

A packaging material, a method of making such a material, and a package made from such material, are disclosed. A substrate comprises at least one sheet of plastic material. An energy-curable coating is applied to one side of the substrate, which will be the outside of the eventual package. The energy-curable coating is cured by exposing it to an electron beam or other appropriate energy. A cold-seal cohesive coating is applied to the other side of the substrate. The package is formed by pressing together portions of the inside surface of at least one sheet of the material having the cold-seal cohesive coating on them to form a seal. Preferably, the cold-seal cohesive coating is applied only to those portions of the material that are to form seams in the eventual package.

Claims

1. A method of making a packaging material, comprising the steps of:

providing a substrate comprising at least one sheet of plastic material, the substrate comprising a first side and a second side;

printing ink on the first side of the substrate;

applying an energy-curable coating to the first side of the substrate over the ink, the energy-curable coating comprising a slip agent;

curing the energy-curable coating and reacting-in the slip agent by exposing the energy-curable coating and slip agent to a suitable energy; and

applying a cold-seal cohesive coating to at least a portion of the second side of the substrate, the energy-curable coating providing a surface for temporary adhesion of the cold seal cohesive coating to the first side of the substrate when the substrate is stored in a roll, without blocking of the cohesive coating upon removal of the cohesive coating from the energy-curable coating.

2. A method according to claim 1, wherein the printing of ink on said first side of the substrate occurs before applying said cold-seal cohesive coating on the second side of the substrate.

3. A method according to claim 2, wherein the printing of ink is performed by a flexographic or rotogravure printing machine.

4. A method according to claim 1, further comprising the steps of:

laminating the printed sheet of plastic and another sheet of plastic together with the printing between them to form said substrate, said substrate having an exposed side opposite the printing;

wherein one of said sheets of plastic forming said substrate is clear; and

applying said energy-curable coating to the exposed side of said clear sheet of plastic.

5. A method according to claim 1, wherein said step of curing comprises exposing said energy-curable coating to an electron beam.

6. A method of making packaging material comprising the steps of:

providing a substrate having a first side and a second side;

printing an image on a first side of a substrate;

applying an energy curable coating on the first side of the substrate over the printed image, the coating including a non-migratory slip agent;

curing the energy curable coating and simultaneously reacting in the slip agent with an energy source to form a substantially transparent release layer on the first side of the substrate;

applying a cold-seal cohesive material to a second side of the substrate;

rolling the substrate so that the cohesive material is contacting the cured coating with the reacted-in slip agent; and

separating the cohesive from the coating without blocking of the cohesive.

7. The method of claim 6 wherein the step of applying the cold-seal cohesive material comprises pattern applying the cold-seal cohesive material on areas of the second side of the substrate where seals are to be formed in the package.

8. The method of claim 7 wherein the step of pattern applying comprises applying the cold-seal cohesive material at a thickness of from about 5 microns to about 7 microns.

9. A method of making a package comprising the steps of:

providing a substrate having a first and second side;

printing an image on a first side of the substrate;

applying an energy curable release coating over the printed image;

providing slip agents in the energy curable release coating;

curing the energy curable release coating with an energy source to form a cured release layer on the substrate, the slip agents becoming reacted in within the coating upon energy curing;

pattern-applying a cold-seal material to at least a portion of a second side of the substrate;

storing the substrate in a roll with the cold-seal material in contact with the release layer, wherein the reacted-in slip agents in the release layer do not poison the cold seal material;

unrolling the substrate such that the pattern-applied cold-seal material remains attached to the second side of the substrate and does not offset onto the release layer;

forming the substrate into the shape of a package; and

pressing the cold-seal coated portions of the second side of the substrate together to form a seal and a package.

10. The method of claim 9 wherein the step of pattern applying comprises applying the cold-seal material at a thickness of from about 5 microns to about 7 microns.

11. The method of claim 9 wherein the curing step comprises the step of exposing the coated substrate to electron beam energy such that the coating absorbs a dosage of from about 2.5 megarads to about 5 megarads.

12. The method of claim 11 wherein the coating absorbs a dosage of from about 3 megarads to about 4 megarads during the curing process.