Reactive hot melt foam

• US 5,616,625 A
• Filed: 02/17/1995
• Issued: 04/01/1997
• Est. Priority Date: 02/17/1995
• Status: Expired due to Term

• Current Assignee: Henkel IP & Holding GmbH (Henkel AG & Co KGaA)
• Original Assignee: National Starch and Chemical Investment Holding Corporation (Ingredion Incorporated)
• Inventors: Nowicki, James W., Hung, Ju-Ming
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): COONEY, JOHN M
• Application Number:
  US08/390,443
• Time in Patent Office: 774 Days
• Field of Search: 521/115, 521/80, 521/128, 521/79, 521/155, 521/159, 525/93, 525/96, 525/111, 525/127, 525/130, 525/455
• US Class Current: 521/79
• CPC Class Codes: B29B 13/022 Melting the material to be shaped
• CPC Class Codes: B29K 2105/0097 Glues or adhesives, e.g. hot melts or thermofusible adhesives
• CPC Class Codes: C08G 18/2081 containing at least two non-condensed heterocyclic rings
• CPC Class Codes: C08G 2170/20 Compositions for hot melt adhesives
• CPC Class Codes: C08G 2170/60 Compositions for foaming; Foamed or intumescent adhesives
• CPC Class Codes: C08J 2375/04 Polyurethanes
• CPC Class Codes: C08J 9/30 by mixing gases into liquid compositions or plastisols, e.g. frothing with air
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: C09J 2475/00 Presence of polyurethane
• CPC Class Codes: C09J 5/08 using foamed adhesives

Abstract

A process for foaming polyurethane reactive hot melt adhesive comprising the steps of:

a) melting a reactive polyurethane adhesive containing 0.05 to 0.5% by weight of a 2,2'"'"'dimorpholinodiethyl ether or di(2,6-dimethylmorpholinodiethyl)ether catalyst in a heated reservoir

b) pumping the adhesive from the heated into a heated reservoir recirculating foaming device;

c) foaming the adhesive by injecting therein an effective amount of an anhydrous gas;

d) discharging a portion of the foamed adhesive through an orifice onto a substrate to be bonded; and

e) recirculating the remaining foamed adhesive back to the foaming device for discharge at a later time.

Claims

1. A process for foaming polyurethane reactive hot melt adhesive comprising the steps of:

a) melting a reactive polyurethane adhesive containing 0.05 to 0.5% by weight of a 2,2'"'"'dimorpholinodiethyl ether or di(2,6-dimethylmorpholinodiethyl)ether catalyst in a heated reservoir;

b) pumping the adhesive from the heated reservoir into a heated recirculating melt foaming device;

c) foaming the adhesive by injecting therein an effective amount of an anhydrous gas;

d) discharging a portion of the foamed adhesive through an orifice onto a substrate to be bonded; and

e) recirculating the remaining foamed adhesive back to the foaming device to be stored for discharge at a time following the initial and subsequent recirculation back to the foaming device.

2. The process of claim 1 wherein the catalyst is present in the adhesive in an amount of 0.075 to 0.2% by weight.

3. The process of claim 1 wherein the catalyst is present in the adhesive in an amount of about 0.1% by weight.

4. The process of claim 1 wherein the catalyst in the adhesive is 2,2'"'"'dimorpholinodiethyl ether.

5. The process of claim 1 wherein the reactive polyurethane adhesive contains residual ethylenic unsaturation.

6. The process of claim 1 wherein the polyurethane adhesive contains a polyurethane prepolymer prepared by the condensation of a diisocyanate with a diol.

7. The process of claim 1 wherein the polyurethane adhesive is foamed using a recirculating Foam Melt unit available from Nordson.