Flame resistant hotmelt adhesive

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 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.

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/cm3;
• 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.

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/cm3;
• and
• a viscosity measured according to ASTM D 3236 at 190° C. from 1,000 to 15,000 mPa·s.

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 1H-NMR of up to 15%.

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.

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.