Thermally stable reactive hot melt urethane adhesive composition having a thermoplastic polymer, a compatible, curing urethane polyester polyol prepolymer and a tackifying agent

• US 4,808,255 A
• Filed: 05/07/1987
• Issued: 02/28/1989
• Est. Priority Date: 05/07/1987
• Status: Expired due to Term

• Current Assignee: H.B. Fuller Licensing & Financing, Inc.
• Original Assignee: HB Fuller Company
• Inventors: Messman, Elizabeth R., Swoboda, Jeffrey M., Bunnelle, William L., Zimmel, John M., Markevka, Virginia C.
• Primary Examiner(s): Gallagher, John J.
• Application Number:
  US07/047,685
• Time in Patent Office: 663 Days
• Field of Search: 156/307.3, 156/331.4, 525/127, 525/130, 525/440, 525/455, 525/451
• US Class Current: 156/307.3
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C08G 2170/20 Compositions for hot melt adhesives
• CPC Class Codes: C08L 23/08 Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 25/02 Homopolymers or copolymers of hydrocarbons
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 31/04 Homopolymers or copolymers of vinyl acetate
• CPC Class Codes: C08L 45/00 Compositions of homopolymers or copolymers of compounds having no unsaturated aliphatic radicals in side chain, and having one or more carbon-to-carbon double bonds in a carbocyclic or in a heterocyclic ring system; Compositions of derivatives of such polymers of cyclic anhydrides or imides C08L35/00; of cyclic esters of polyfunctional acids C08L31/00
• CPC Class Codes: C08L 57/02 Copolymers of mineral oil hydrocarbons
• CPC Class Codes: C08L 75/06 from polyesters
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• CPC Class Codes: C09J 175/06 from polyesters

Abstract

Reactive hot melt adhesive compositions combining the characteristics of hot melt adhesives and curing urethane adhesive can be prepared by blending an ethylene-vinyl monomer thermoplastic polymer having sufficient structural integrity to provide cohesive strength with a urethane prepolymer and a tackifying agent. The composition has sufficient green strength to form initial bonds. Additionally, over time, the composition cures to a final rigid, resilient quality structural adhesive bond.

Claims

1. A reactive hot melt urethane adhesive composition having extended pot stability, bond heat stability, green strength and cured bond strength which comprises:

(a) a urethane prepolymer composition comprising the reaction product of an isocyanate compound and a polyester-polyol prepared by reacting a polyfunctional carboxylic acid compound and an aliphatic or cycloaliphatic diol or triol compound;

(b) about 1 to 200 parts by weight per each one hundred parts of the prepolymer of a structural thermoplastic ethylene vinyl monomer copolymer composition having a melt index of about 0.2 to 1000 and a vinyl monomer content of about 10 to 60 wt-%; and

(c) about 1 to 200 parts by weight per each one hundred parts by weight of the prepolymer of a compatible aliphatic, aromatic or aliphatic-aromatic tackifying resin.

2. The adhesive of claim 1 wherein the vinyl monomer content comprises 18-50 wt-%.

3. The adhesive of claim 1 wherein the polyol of the polyester-polyol comprises a cycloaliphatic diol.

4. The adhesive of claim 3 wherein the cycloaliphatic diol comprises a dihydroxyalkyl cyclohexane.

5. The adhesive of claim 4 wherein the dihydroxyalkyl cyclohexane comprises a 1,4-dihydroxymethyl-cyclohexane.

6. The adhesive of claim 3 wherein the aliphatic diol comprises a 1,6-hexane diol.

7. The adhesive of claim 1 wherein the polyfunctional carboxylic acid compound comprises an aliphatic dicarboxylic acid compound.

8. The adhesive of claim 7 wherein the aliphatic dicarboxylic acid compound comprises a dimer fatty acid.

9. The adhesive of claim 1 wherein the ethylene vinyl monomer composition comprises an ethylene vinyl acetate copolymer.

10. The adhesive of claim 9 wherein the ethylene vinyl acetate copolymer comprises 14 to 33 wt-% vinyl acetate and the tackifying resin comprises an aliphatic or aliphatic-aromatic resin.

11. The adhesive of claim 9 wherein the ethylene vinyl acetate comprises 28-50 wt-% vinyl acetate and the tackifying resin comprises an aromatic tackifying resin or aliphatic-aromatic resin.

12. A method of bonding at least two surfaces which comprises applying to a bondline that can join two surfaces an effective bonding amount of the adhesive of claim 1 and curing the adhesive.

13. The method of claim 12 wherein the adhesive is cured with atmospheric moisture.