LOW APPLICATION TEMPEARATURE AMORPHOUS POLY-a-OLEFIN ADHESIVE

• US 20130158176A1
• Filed: 02/20/2013
• Published: 06/20/2013
• Est. Priority Date: 08/26/2010
• Status: Active Grant

• Current Assignee: Henkel AG & Co KGaA
• Original Assignee: Henkel Corporation (Henkel AG & Co KGaA)
• Inventors: Hu, Yuhong, Paul, Charles W., Alvarado, Salvador, Desai, Darshak
• Granted Patent: US 9,000,079 B2
• Time in Patent Office: Days
• US Class Current: 524/274
• CPC Class Codes: B32B 2037/1215 Hot-melt adhesive
• CPC Class Codes: B32B 2555/02 Diapers or napkins
• CPC Class Codes: B32B 37/1207 Heat-activated adhesive B32B37/04 takes precedence
• CPC Class Codes: B32B 37/1284 Application of adhesive
• CPC Class Codes: B32B 37/18 involving the assembly of discrete sheets or panels only
• CPC Class Codes: C09J 123/0815 Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: C09J 123/10 Homopolymers or copolymers of propene
• CPC Class Codes: C09J 123/14 Copolymers of propene C09J123/16 takes precedence
• CPC Class Codes: C09J 123/18 Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
• CPC Class Codes: C09J 123/20 having four to nine carbon atoms
• CPC Class Codes: C09J 2301/304 the adhesive being heat-activatable, i.e. not tacky at temperatures inferior to 30°C
• CPC Class Codes: C09J 2400/263 in the substrate
• CPC Class Codes: C09J 5/06 involving heating of the applied adhesive

Abstract

It has been discovered that amorphous polybutene copolymers that have a softening point of from about 70 to about 105° C. and viscosity of less than about 1,900 cP at 190° C. possesses desirable properties and may be used to make a low application temperature hot melt adhesive for disposable absorbent articles.

Claims

1. A hot melt adhesive comprising at least 45 wt %, based on the adhesive, of an amorphous polybutene copolymer which has a softening point of from about 70 to about 105°

C. and viscosity of less than about 1,900 cP at 190°

C., and wherein the hot melt adhesive has a viscosity of less than about 6,000 cP at 150°

C.

2. The hot melt adhesive of claim 1 wherein the amorphous polybutene copolymer has a tan(δ

) value greater than 30 at 140°

C.

3. The hot melt adhesive of claim 1 wherein the amorphous polybutene copolymer further comprises propylene comonomer.

4. The hot melt adhesive of claim 3 wherein the amorphous polybutene copolymer has a butene content greater than about 40%.

5. The hot melt adhesive of claim 1 further comprising a tackifier which has a softening point greater than or equal to 80°

C.

6. The hot melt adhesive of claim 4 wherein the tackifier has a softening point greater than or equal to 100°

C.

7. The hot melt adhesive of claim 4 wherein the tackifier is selected from the group consisting of C5 resins, petroleum distillates, hydrogenated hydrocarbons, C5/C9, polyterpenes, rosin, hydrogenated rosin, and rosin esters and mixtures thereof.

8. The hot melt adhesive of claim 1 further comprising a crystalline wax which has a melting point greater than 60°

C.

9. The hot melt adhesive of claim 8 wherein the crystalline wax is selected from the group consisting of Fischer-Tropsch wax, petroleum based wax, conventional wax, natural-based wax, functionalized wax, polyolefin copolymers and mixtures thereof.

10. The hot melt adhesive of claim 1 which is essentially free of wax and/or plasticizer.

11. The hot melt adhesive of claim 1 which comprises greater than 50% of the amorphous polybutene copolymer.

12. The hot melt adhesive of claim 11 which comprises greater than 60% of the amorphous polybutene copolymer.

13. The hot melt adhesive of claim 1 wherein the adhesive has a tensile peak value greater than 55 psi at 23°

C. at a pulling rate of 12 in/min.

14. An article comprising the adhesive of claim 1.

15. The article of claim 14 which is a personal care, health, medical, household or industrial product.

16. The article of claim 15 which is a diaper, training pants, feminine hygiene pad, meat pads and adult incontinence products.

17. A method comprising applying the adhesive of claim 1 at 150°

C. or below to a first substrate;

applying a second substrate onto the adhesive, thereby forming a bond.

18. The method of claim 17 wherein the substrate is a nonwoven film.

19. The method of claim 18 wherein the adhesive is applied onto the substrate by melt spraying, swirl patterning, random spraying and/or slot coating with an add-on-range of about 0.1 to about 20 g/m².

20. The method of claim 19 wherein the adhesive is applied with an add-on-range of about 0.1 to about 10 g/m².