Extrudable hotmelt adhesives based on branched SIS polymers

Patent metadata

Field	Value
Publication number	US-10233364-B2
Application number	US-201615183871-A
Country	US
Kind code	B2
Filing date	Jun 16, 2016
Priority date	Dec 17, 2013
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

The invention relates to a hotmelt adhesive comprising 10 to 40 wt % of at least one branched styrene-isoprene-styrene block copolymer having a weight percentage diblock fraction in the polymer of less than 30% and a melt flow index of less than 5 g/10 minutes at 200° C. under a test load of 5 kg; 0 to 40 wt % of at least one styrene polymer or styrene copolymer; 20 to 60 wt % of at least one tackifying resin; 0 to 15 wt % of at least one plasticizer; and 0 to 16 wt % of additives and auxiliaries selected from stabilizers, adhesion promoters, fillers or pigments, waxes and/or other polymers. Also included are the use thereof to bond films, and products, especially packaging products, that include this adhesive.

First claim

The invention claimed is:

1. An extrudable hotmelt adhesive comprising:
a) 10 to 40 wt % of a star-shaped styrene-isoprene-styrene block copolymer having more than 10 arms and a weight percentage diblock fraction in the polymer of less than 30% and a melt flow index of less than 5 g/10 minutes at 200° C. under a test load of 5 kg;
b) 0 to 40 wt % of a styrene polymer or a styrene copolymer, having a melt flow index of less than 100 g/10 minutes at 200° C. under a test load of 5 kg;
c) 20 to 60 wt % of a tackifying resin;
d) 0 to 15 wt % of a plasticizer; and
e) 0 to 16 wt % of an additive selected from a stabilizer, adhesion promoter, filler, pigment, wax or other polymer than (a) and (b)

wherein the hotmelt adhesive (i) has a viscosity of more than 50,000 mPas, at 220° C. (Brookfield CAP, spindle 8) and/or (ii) has a softening point of more than 100° C.

2. The extrudable hotmelt adhesive according to claim 1 , characterized in that
(a) the star-shaped styrene-isoprene-styrene block copolymer has a weight percentage diblock fraction in the polymer of less than 20%; and
(b) the styrene polymer or the styrene copolymer, having a melt flow index of less than 20 g/10 minutes at 200° C. under a test load of 5 kg, is selected from styrene-ethylene/butylene-styrene (SEBS), styrene-ethylene/propylene-styrene (SEPS), styrene-ethylene-propylene (SEP), styrene-butadiene-styrene (SBS) and styrene-isoprene/butadiene-styrene (SIBS) block copolymers.

3. The extrudable hotmelt adhesive according to claim 1 , characterized in that the tackifying resin is a fully or partially hydrogenated hydrocarbon resin, a natural resin based on rosin or tall oil resin, a pentaerythritol or glycerol ester thereof, or a mixture thereof.

4. The extrudable hot melt adhesive according to claim 3 , characterized in that the fully or partially hydrogenated hydrocarbon resin is an aromatically modified resin selected from the group consisting of polyterpene, terpene phenol resin, 1,3-pentadiene resin, cyclopentadiene resin, 2-methyl-2-butene copolymer, or derivatives thereof.

5. The extrudable hotmelt adhesive according to claim 3 , characterized in that the tackifying resin comprises:
(a) 20-60 wt % of an aromatically modified resin, a polyterpene, a terpene-phenol resin, a 1,3-pentadiene resin, a cyclopentadiene resin, a 2-methyl-2-butene copolymer or derivatives thereof, having a softening point from 80 to 150° C.;
(b) 20-60 wt % of a natural resin based on rosin or tall oil resin, pentaerythritol or glycerol ester thereof, fully or partially hydrogenated hydrocarbon resin, or derivatives thereof, having a softening point from 80 to 140° C.; and
(c) 0-20 wt % of an aromatically modified resin, polyterpene, terpene phenol resin, 1,3-pentadiene resin, cyclopentadiene resin, 2-methyl-2-butene copolymer or derivatives thereof, having a softening point from 0 to 50° C.;
wherein the wt % is based on the total weight of the extrudable hotmelt adhesive.

6. The extrudable hotmelt adhesive according to claim 5 , characterized in that the tackifying resin comprises:
(a) 35-55 wt % of the aromatically modified resin, polyterpene, terpene-phenol resin, cyclopentadiene resin or derivatives thereof;
(b) 20-60 wt % of the polyterpene, terpene-phenol resin, cyclopentadiene resin, or the derivatives thereof, having a softening point from 95 to 105° C.; and
(c) 0-20 wt % of the aromatically modified resin, polyterpene, terpene-phenol resin, 1,3-pentadiene resin, cyclopentadiene resin, 2-methyl-2-butene copolymer or derivatives thereof, having a softening point from 8 to 12° C.

7. The extrudable hotmelt adhesive according to claim 1 , characterized in that the plasticizer is selected from a mineral oil, poly(iso)butylene, liquid or pasty hydrogenated hydrocarbon or low-molecular polyolefin, having a molecular weight Mw of less than 5,000.

8. The extrudable hotmelt adhesive according to claim 7 , characterized in that the plasticizer is poly(iso)butylene.

9. The extrudable hotmelt adhesive according to claim 1 , characterized in that the additive comprises 0.5 to 5 wt % of a paraffin wax, microcrystalline wax, or derivatives thereof, having a dropping point determined in accordance with ASTM D-3954 from 130 to 170° C.

10. The extrudable hotmelt adhesive according to claim 9 , characterized in that the additive further comprises:
(1) up to 3 wt % of a stabilizer; and
(2) 2 to 5 wt % of (i) a terpolymer of ethylene, acrylic acid ester and maleic acid anhydride, having a melt flow index of 100-300/10 minutes at 190° C. under a test load of 2.6 kg (ISO 1133), (ii) an aromatically modified hydrocarbon resin, (iii) a Fischer-Tropsch wax having a melting point of 90-110° C., or mixtures thereof.

11. A multi-layer film comprising an outer layer, a sealing layer, and the extrudable hotmelt adhesive according to claim 1 , wherein the extrudable hot melt adhesive is disposed between the outer layer and the sealing layer.

12. The multi-layer film according to claim 11 , characterized in that the outer layer is a polyethylene or polyethylene terephthalate, and the sealing layer is polyethylene having a density from 0.91-0.94 g/cm 3 .

13. The multi-layer film according to claim 12 , characterized in that the outer layer is polyethylene.

14. A resealable packaging product comprising the multi-layer film according to claim 11 .

Assignees

• Henkel Ag & Co Kgaa

Inventors

• Heemann Marcus
• Kostyra Sebastian
• Puerkner Eckhard
• Kasper Dirk

Classifications

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title

• C09J7/387

  Block-copolymers · CPC title

• B32B27/20

  using fillers, pigments, thixotroping agents · CPC title

• B32B2307/4026

  within the layer by addition of a colorant, e.g. pigments, dyes · CPC title

• C08L53/025

  modified · CPC title