Flame resistant hotmelt adhesive
A hotmelt adhesive composition comprising 15 to 45% by weight of at least one tackifying resin, and 20 to 60% by weight of a mixture of at least one single-site catalyzed propylene homopolymer (A) and at least one propylene copolymer (B), wherein the propylene homopolymer (A) has a weight average molecular weight of 20,000 to 145,000, the propylene copolymer (B) has an ethylene comonomer content of 5 to 25% by weight, and the weight ratio of propylene homopolymer (A) to propylene copolymer (B) is from 1:3 to 3:1, wherein the hotmelt adhesive further comprises at least one of the following two components (a) and (b): (a) a particulate phosphorous based compound in an amount of 15 to 40% by weight, or (b) a room temperature liquid phosphorous based compound in an amount of 4 to 15% by weight.
1. A hotmelt adhesive composition comprising, based on the total weight of the composition:
from 15% to 45% by weight at least one tackifying resin;
from 20% to less than 60% by weight a mixture of at least one single-site catalyzed propylene homopolymer (A) and at least one propylene copolymer (B); and
at least one of the following two components:
a particulate phosphorous based compound in an amount from 15% to 40% by weight, and
a room temperature liquid phosphorous based compound in an amount from four % to 15% by weight,
wherein the propylene homopolymer (A) has a weight average molecular weight from 20,000 to 145,000, the propylene copolymer (B) has an ethylene comonomer content in an amount from five % to 25% by weight, and the weight ratio of propylene homopolymer (A) to propylene copolymer (B) is from 1:3 to 3:1.
2. The hotmelt adhesive composition of claim 1 , wherein the particulate phosphorous based compound is a polyphosphate.
3. The hotmelt adhesive composition of claim 1 , wherein the particulate phosphorous based compound is ammonium polyphosphate.
4. The hotmelt adhesive composition of claim 1 , wherein the particulate phosphorous based compound is encapsulated ammonium polyphosphate.
5. The hotmelt adhesive composition of claim 1 , wherein the particulate phosphorous based compound is ammonium polyphosphate encapsulated with melamine.
6. The hotmelt adhesive composition of claim 1 , wherein the room temperature liquid phosphorous based compound has a phosphorous content from eight % to 25% by weight.
7. The hotmelt adhesive composition of claim 1 , wherein the room temperature liquid phosphorous based compound is at least one from the group of phosphonates, phosphate esters, phosphine, phosphine oxide, and phosphates.
8. The hotmelt adhesive composition of claim 1 , wherein the room temperature liquid phosphorous based compound is a cyclic phosphonate.
9. The hotmelt adhesive composition of claim 1 , further comprising a hindered amine light stabilizer in an amount from 0.5% to three % by weight.
10. The hotmelt adhesive composition of claim 1 , wherein the hotmelt adhesive composition includes the particulate phosphorous based compound in an amount from 15% to 40% by weight, based on the total weight of the composition.
11. The hotmelt adhesive composition of claim 1 , wherein the hotmelt adhesive composition includes the room temperature liquid phosphorous based compound in an amount from four % to 15% by weight, based on the total weight of the composition.
12. The hotmelt adhesive composition of claim 1 , wherein the composition further comprises a functionalized polyolefin.
13. The hotmelt adhesive composition of claim 1 , wherein the composition further comprises a wax.
14. The hotmelt adhesive composition of claim 1 , wherein the propylene homopolymer (A) has at least one of:
a density measured according to ISO 1183 from 0.85 to 0.89 g/cm 3 ;
a softening point measured according to ISO 4625 from 80° C. to 100° C.;
a viscosity measured according to ASTM D 3236 at 190° C. from 4,000 to 380,000 mPa·s;
a weight average molecular weight from 30,000 to 100,000; and
a molecular weight distribution (Mw/Mn) of 2.5 or less.
15. The hotmelt adhesive composition of claim 1 , wherein the propylene copolymer (B) has at least one of:
an ethylene comonomer content from five % to 14% by weight;
a density measured according to ISO 1183 from 0.85 to 0.89 g/cm 3 ; and
a viscosity measured according to ASTM D 3236 at 190° C. from 1,000 to 15,000 mPa·s.
16. The hotmelt adhesive composition of claim 1 , wherein the tackifying resin comprises at least one of the following:
is a hydrogenated hydrocarbon resin;
has a softening point measured according to ASTM E-28 from 85° C. to 140° C.; and
has an aromaticity measured by 1 H-NMR of up to 15%.
17. The hotmelt adhesive composition of claim 1 , wherein the tackifying resin is a mixture of at least one first tackifying resin (T1), and a second tackifying resin (T2), wherein
the at least one first tackifying resin (T1) has a softening point measured according to ASTM E-28 from 105° C. to 140° C., and
the second tackifying resin (T2) has a softening point measured according to ASTM E-28 from 80° C. to 100° C. and an aromaticity measured by 1 H-NMR from five % to 15%, and
the weight ratio T1/T2 of first tackifying resin (T1) to second tackifying resin (T2) is from 0.8 to two.
18. The hotmelt adhesive composition of claim 1 , wherein
the propylene homopolymer (A) is a mixture of a first propylene homopolymer (A1) and a second propylene homopolymer (A2),
the first propylene homopolymer (A1) has a softening point measured according to ISO 4625 from 85° C. to 100° C., a viscosity measured according to ASTM D 3236 at 190° C. from 4,000 to 20,000 mPa·s and a weight average molecular weight (Mw) from 20,000 to 60,000;
the second propylene homopolymer (A2) has a softening point measured according to ISO 4625 from 115° C. to 130° C., a melt flow rate measured according to ASTM D 1238 at 230° C. under a load of 2.16 kg from 30 to 100 g/10 min, and a weight average molecular weight from 100,000 to 145,000; and
the weight ratio of first propylene homopolymer (A1) to second propylene homopolymer (A2) is from 1.5:1 to 4:1.
19. The hotmelt adhesive composition of claim 1 , wherein the composition comprises, based on the total weight of the composition
from 20% to 40% by weight the at least one tackifying resin;
from 20% to 60% by weight the mixture of at least one single-site catalyzed propylene homopolymer (A) and at least one propylene copolymer (B);
from 0.5% to two % by weight maleic anhydride modified polypropylene;
from 0.5% to two % by weight Fischer-Tropsch wax; and
at least two components selected from the following three components:
an encapsulated ammonium polyphosphate in an amount from 20% to 35% by weight;
a hindered amine light stabilizer in an amount from 0.5% to two % by weight, and
the room temperature liquid phosphorous based compound in an amount of from five % to 12%, and
wherein the composition is halogen-free.
20. The hotmelt adhesive composition of claim 1 , wherein the composition has
a Brookfield viscosity measured according to ASTM D 3236 at 180° C. from 2,000 to 50,000 mPa·s; and
a softening point measured according to ASTM E 28 from 95° C. to 140° C.