Hot melt pressure sensitive adhesive designed for use on high density spun polyolefin film

• US 5,869,562 A
• Filed: 03/28/1997
• Issued: 02/09/1999
• Est. Priority Date: 03/28/1997
• Status: Expired due to Fees

• Current Assignee: HB Fuller Company
• Original Assignee: H.B. Fuller Licensing & Financing, Inc.
• Inventors: Lindquist, Jeffrey S., Simmons, Eugene R., Cameron, Janelle C.
• Primary Examiner(s): Szekely, Peter A.
• Application Number:
  US08/829,712
• Time in Patent Office: 683 Days
• Field of Search: 524/271, 524/274, 524/499, 524/505, 525/98, 525/99, 525/88
• US Class Current: 524/505
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes

Abstract

This invention relates to an envelope coated with a hot melt pressure sensitive adhesive composition preferably comprising a) from about 10% to about 40% by weight in the adhesive of at least one block copolymer selected from the group consisting of styrene-isoprene-styrene block copolymers, styrene-butadiene-styrene block copolymers and mixtures thereof wherein the block copolymers comprise from about 15% to about 35% styrene by weight in the copolymer and diblock contents from about 0% to about 90% by weight in the copolymer; and b) from about 60% to about 90% by weight in the adhesive of a modifier selected from the group consisting of solid tackifying resins, liquid tackifying resins, liquid elastomers and mixtures thereof. The invention further relates to an improved oil-free pressure sensitive adhesive that is low in viscosity and provides a destructive bond and resists deformation of high density spun polyolefin materials.

Claims

1. A hot melt pressure sensitive adhesive, comprising:

a) from about 10% to about 40% by weight of the adhesive of at least one block copolymer selected from the group consisting of styrene-isoprene-styrene block copolymers, styrene-butadiene-styrene block copolymers and mixtures thereof wherein said block copolymers comprise from about 15% to about 35% styrene by weight of the block copolymer and a diblock content from about 0% to about 90% by weight in the copolymer wherein the total styrene-isoprene diblock content does not exceed 55% by weight of the total polymer polymer, content a); and

b) from about 60% to about 90% by weight of the adhesive of a modifier selected from the group consisting of solid tackifying resins having a melt point from about 70°

C. to about 150°

C., liquid tackifying resins, liquid elastomers and mixtures thereof;

wherein the resultant adhesive is oil-free and provides a destructive bond to, and resists deformation of said envelope.

2. The adhesive of claim 1 wherein the viscosity at 175°

C. is less than about 5000 cPs.

3. The adhesive of claim 1 wherein the 180°

peel is greater than about 700 g/cm.

4. The adhesive of claim 1 wherein the liquid elastomer is selected from the group consisting of polybutene, polyisobutylene, polyisoprene and mixtures thereof.

5. The adhesive of claim 1 wherein the liquid tackifying resin is a hydrocarbon.

6. The adhesive of claim 1 wherein the at least one block copolymer is a styrene-isoprene-styrene block copolymer comprising from about 15% to about 25% styrene by weight in the copolymer.

7. The adhesive of claim 1 further comprising up to about 10% by weight in the adhesive of a thermoplastic polymer selected from the group consisting of rubbery block copolymers;

homopolymers, copolymers and terpolymers of ethylene;

homopolymers, copolymers and terpolymers of propylene; and

mixtures thereof.

8. The adhesive of claim 1 comprising from about 20% to about 30% by weight of at least one block copolymer;

from about 30% to about 60% by weight of at least one solid tackifying resin having a melt point from about 70°

C. to about 150°

C.; and

from about 20% to about 40% by weight in the adhesive of a modifier selected from the group consisting of liquid tackifying resins, liquid elastomers and mixtures thereof.

9. The adhesive of claim 1 wherein the resultant adhesive has a SAFT of greater than about 35°

C.