Polyolefin-based hot melt adhesives with improved properties

Patent metadata

Field	Value
Publication number	US-11299657-B2
Application number	US-201514688155-A
Country	US
Kind code	B2
Filing date	Apr 16, 2015
Priority date	Apr 16, 2014
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A hot melt adhesive composition made from polypropylene copolymer or polypropylene impact copolymer, a polyolefin elastomer, a low density polyethylene, a tackifying resin, a plasticizer, and a nucleating agent. These adhesives are fast setting yet show an improved balance of mechanical properties making them useful for hygiene, construction, and packaging applications.

First claim

We claim:

1. A hot melt adhesive composition, comprising a blend of the following components:
about 2% to about 20% of a polypropylene random copolymer having a melt flow rate of between about 10 and about 250 g/10 min according to ASTM D-1238 using a temperature of 230° C. and a 2.16 kg weight or mixtures thereof, wherein the comonomer is selected from the group consisting of ethylene and a 1-alkene;
about 2.5% to about 20% by weight of an olefin based elastomer or a mixture of said olefin based elastomers, wherein the polypropylene random copolymer has a higher crystallinity than the olefin based elastomer;
about 2.5% to 20% by weight of a linear low density polyethylene or mixture of linear low density polyethylenes, wherein said linear low density polyethylene has a melt index value of from about 100 to about 1000 g/10 min (190° C./2.16 kg) and a density less than 0.94 g/cc as determined by the method described in ASTM D792-00;
about 0.05 to about 5.0% by weight of a polyolefin nucleating agent comprising dibenzylidene sorbitol derivatives;
about 10% to about 70% by weight of tackifying resin having a softening point of at least about 80° C. and up to about 140° C.;
about 24.6% to about 60% by weight of a plasticizer;
about 0.1% to about 5% of a stabilizer or antioxidant; and wherein the components total 100% by weight of the composition, the viscosity of the composition is equal to or less than about 20,000 cP at 163° C. and the tan-delta at 75° C. of the composition is from 0.2 to 0.3.

2. The hot melt adhesive composition of claim 1 , comprising about 2.5% to about 15% by weight of said polypropylene random copolymer or said mixtures thereof.

3. The hot melt adhesive composition of claim 1 , comprising about 5.0% to about 15% by weight of said olefin based elastomer or said mixture of said olefin based elastomers.

4. The hot melt adhesive composition of claim 1 , comprising about 0.1% to about 2.5% by weight of said polyolefin nucleating agent.

5. The hot melt adhesive composition of claim 1 , comprising about 0.2% to about 1.0% by weight of said polyolefin nucleating agent.

6. The hot melt adhesive composition of claim 1 , comprising about 10% to about 60% by weight of said tackifying resin.

7. The hot melt adhesive composition of claim 1 , comprising about 25% to about 50% by weight of said tackifying resin.

8. The hot melt adhesive composition of claim 1 , wherein said tackifying resin has a softening point of from about 85° C. to about 135° C.

9. The hot melt adhesive composition of claim 1 , comprising about 24.6% to about 55% by weight of said plasticizer.

10. The hot melt adhesive composition of claim 1 , comprising about 24.6% to about 50% by weight of said plasticizer.

11. The hot melt adhesive composition of claim 1 , wherein the components further comprise about 1% to about 15% by weight of an additional auxiliary polymer selected from the group consisting of EVA, APAO, PE, PP, PB, SIS, SI, SBS, SB, SIBS, SEB, SEBS, SEP, SEPS, SBBS, SEEPS and blends of each thereof, wherein the auxiliary polymer is a polymer different from said polypropylene random copolymer, said olefin based elastomer, said linear low density polyethylene, and said tackifying resin.

12. The hot melt adhesive composition of claim 1 , wherein the components further comprise about 0.1% to about 5% by weight of a wax selected from the group consisting of a paraffin wax, a microcrystalline wax, a polyethylene wax, and a polypropylene wax.

13. A laminate comprising the adhesive composition of claim 1 used to make an end product selected from the group consisting of a disposable diaper, a sanitary napkin, a bed pad, a bandage, a surgical drape, a tape, a label, a plastic sheet, a nonwoven sheet, a paper sheet, a cardboard, a book, a filter, or a package.

14. The hot melt adhesive composition of claim 1 , wherein the components further comprise additives, surfactants, fillers, or other auxiliary components.

15. The hot melt adhesive composition of claim 1 , wherein said olefin based elastomer comprises a metallocene-catalyzed propylene based elastomer.

16. The hot melt adhesive composition of claim 1 , wherein said plasticizer comprises polyisobutylene.

17. The hot melt adhesive composition of claim 15 , wherein the metallocene-catalyzed propylene based elastomer comprises a copolymer of propylene and ethylene.

18. The hot melt adhesive composition of claim 1 , wherein the composition does not contain ethylene-propylene rubbers.

19. A hot melt adhesive composition, comprising a blend of the following components:
about 2% to about 20% of a polypropylene random copolymer having a melt flow rate of between about 10 and about 250 g/10 min according to ASTM D-1238 using a temperature of 230° C. and a 2.16 kg weight or mixtures thereof, wherein the comonomer is ethylene and the polypropylene random copolymer consists of a semi-crystalline phase comprising polypropylene homopolymer and rubbery phase comprising ethylene-propylene copolymer;
about 2.5% to about 20% by weight of an olefin based elastomer or a mixture of said olefin based elastomers, wherein the polypropylene random copolymer has a higher crystallinity than the olefin based elastomer;
about 2.5% to 20% by weight of a linear low density polyethylene or mixture of linear low density polyethylenes, wherein said linear low density polyethylene has a melt index value of from about 100 to about 1000 g/10 min (190° C./2.16 kg) and a density less than 0.94 g/cc as determined by the method described in ASTM D792-00;
about 0.05 to about 5.0% by weight of a polyolefin nucleating agent comprising dibenzylidene sorbitol derivatives;
about 10% to about 70% by weight of tackifying resin having a softening point of at least about 80° C. and up to about 140° C.;
about 24.6% to about 60% by weight of a plasticizer;
about 0.1% to about 5% of a stabilizer or antioxidant; and wherein the components total 100% by weight of the composition, the viscosity of the composition is equal to or less than about 20,000 cP at 163° C.

Assignees

• Bostik Inc

Inventors

• Gray Steven Daniel
• Hu Miao

Classifications

• C08L23/16

  Ethylene-propylene or ethylene-propylene-diene copolymers · CPC title

• C08K5/0016

  Plasticisers · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C09J123/14 Primary

  Copolymers of propene (C09J123/16 takes precedence) · CPC title

• C08K5/0083

  Nucleating agents promoting the crystallisation of the polymer matrix · CPC title