Use of meltable acrylate polymers for producing contact adhesive layers

• US 9,212,291 B2
• Filed: 03/30/2009
• Issued: 12/15/2015
• Est. Priority Date: 03/31/2008
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Beyers, Cornelis Petrus, Kirsch, Stefan, Licht, Ulrike
• Primary Examiner(s): Wood, Ellen S
• Application Number:
  US12/933,209
• Publication Number:
  US 20110014404A1
• Time in Patent Office: 2,451 Days
• Field of Search: 428/34.7, 428/35.6, 428/349, 428/40.1, 428/215
• US Class Current: 1/1
• CPC Class Codes: B32B 2250/24 All layers being polymeric
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2307/31 Heat sealable
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/7242 Non-permeable
• CPC Class Codes: B32B 2307/7265 Non-permeable
• CPC Class Codes: B32B 2307/748 Releasability
• CPC Class Codes: B32B 2435/00 Closures, end caps, stoppers
• CPC Class Codes: B32B 2439/00 Containers; Receptacles closures therefor B32B2435/00
• CPC Class Codes: B32B 2439/70 Food packaging
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/18 characterised by the use of special additives
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/302 comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
• CPC Class Codes: B32B 27/306 comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/06 permitting easy separation
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B65D 77/2096 : Adhesive means
• CPC Class Codes: C09D 133/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09J 133/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: Y10T 428/1352 : Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/273 : of coating
• CPC Class Codes: Y10T 428/31797 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31924 : Including polyene monomers
• CPC Class Codes: Y10T 428/31928 : Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31935 : Ester, halide or nitrile of addition polymer

Abstract

The present invention relates to the use of meltable acrylate polymers for producing contact adhesive layers in resealable packagings. Moreover, the invention relates to multiple-layer films which have a contact adhesive layer on the basis of meltable acrylate polymers, to a method for producing said multiple-layer films, and to the use of said multiple-layer films for producing resealable packagings.

Claims

1. A reclosable pack, comprising:

at least one multilayer film comprising;

a) a backing film selected from the group consisting of a transparent polymer film and a metallized polymer film,

b) a layer of pressure-sensitive adhesive formed from an acrylate polymer having a glass transition temperature<

−

20°

C., determined according to ASTM-D 3418/82, comprising 1 to 30 mmol of a copolymerized photoinitiator per kg of acrylate polymer, the acrylate polymer comprising, in reacted form, monoethylenically unsaturated monomers M and the copolymerized photoinitiator, the monomers M comprising;

b1) at least 80% by weight, based on the total weight of the acrylate polymer, of at least one monomer A selected from the group consisting of C₃-C₂₀ alkyl acrylates;

b2) 1 to 20% by weight of at least one monomer B selected from the group consisting of C₁-C₄ alkyl methacrylates, methyl acrylate, and ethyl acrylate;

b3) up to 10% by weight of at least one nonaromatic, monoethylenically unsaturated monomer C, which is selected from the group consisting of monoethylenically unsaturated C₃-C₈ monocarboxylic acids, amides of monoethylenically unsaturated C₃-C₈ monocarboxylic acids, monoethylenically unsaturated C₄-C₈ dicarboxylic acids, mono-C₁-C₂₀ alkyl esters of monoethylenically unsaturated C₄-C₈ dicarboxylic acids, and hydroxyalkyl esters of monoethylenically unsaturated C₃-C₈ monocarboxylic acids,

wherein weight fractions of monomers A, B and C add up to 100% by weight, and the acrylate polymer is crosslinked by UV radiation,

wherein the photoinitiator has the formula (I);

2. The reclosable pack according to claim 1, wherein the backing film is a polyolefin film or polyester film.

3. The reclosable pack according to claim 1, wherein the backing film is a polyethylene terephthalate film.

4. The reclosable pack according to claim 1, wherein the sealable layer comprises polyethylene.

5. The reclosable pack according to claim 1, wherein the layer of pressure-sensitive adhesive has an average coating thickness of 1 to 50 g/m².

6. The reclosable pack according to claim 1, comprising two packaging elements connected to one another via the sealable layer, one of the packaging elements being the multilayer film comprising:

a) the backing film which is a polyolefin film or a polyester film.

7. The reclosable pack according to claim 1, wherein the multilayer film is in the form of a closure film.

8. The reclosable pack according to claim 1, wherein the multilayer film is in the form of a container molding.

9. The reclosable pack according to claim 1, wherein the sealable layer consists of polyethylene.

10. The reclosable pack according to claim 6, wherein the multilayer film is in the form of a closure film.

11. The reclosable pack according to claim 6, wherein the multilayer film is in the form of a container molding.

12. The reclosable pack of claim 1 which is in the form of a resealable packaging in which the layer of the pressure-sensitive adhesive is separable from the sealable layer such that after 10 opening/closing events the bond strength between the layer of the pressure-sensitive adhesive and the sealable layer according to Finat # 1 is at least 0.5 N/10 mm.

13. The reclosable pack of claim 1, which is operable by cohesive fracture of the layer of the pressure-sensitive adhesive when first opened.

14. The reclosable pack according to claim 1, wherein formula (I) R¹ is butane-1,4-diyl, R² is a hydrogen atom, and R³ is a phenyl group.

15. The reclosable pack according to claim 1, wherein the acrylate polymer comprises no polyethylenically unsaturated monomer.

16. The reclosable pack according to claim 1, wherein the acrylate polymer consists of monomers A, B, C and the photoinitiator.

17. The reclosable pack according to claim 1, wherein the backing film is a transparent polyethylene terephthalate polymer, the acrylate polymer consists of ethylhexyl acrylate, methyl methacrylate, acrylic acid and the photoinitiator, and the sealable layer is a polyethylene polymer.

18. The reclosable pack according to claim 1, further comprising a polyethylene layer directly adjacent to the sealable layer and a polyethylene terephthalate layer directly adjacent to the polyethylene layer.

19. The reclosable pack according to claim 1, wherein R¹ is a divalent organic radical having 4-30 carbon atoms.