HOT MELT COMPOSITIONS INCLUDING STYRENE BLOCK COPOLYMER AND WAX
The hot melt compositions of this invention include from 15% by weight to 60% by weight of a styrene block copolymer, from 15% to 75% by weight of a wax having a Congealing Point (ASTM D938) of from 45° C. to 90° C. and optionally a propylene based polymer. The hot melt composition can be free of both tackifying agent and plasticizer and is useful in a variety of hygiene applications.
1 . A hot melt composition comprising:
15% by weight to 60% by weight of a styrene block copolymer,
15% by weight to 75% by weight of a wax having a Congealing Point (ASTM D938) of from 45° C. to 90° C., and
no greater than 10% by weight of a liquid plasticizer.
2 . The hot melt composition of claim 1 being free of liquid plasticizer.
3 . The hot melt composition of claim 1 having a total polymer content of from 15% by weight to 45% by weight.
4 . The hot melt composition of claim 1 comprising 25% by weight to 75% by weight of the wax.
5 . The hot melt composition of claim 1 further comprising 5% by weight to 40% by weight of a propylene based polymer.
6 . The hot melt composition of claim 5 wherein the propylene based polymer has a viscosity at 190° C. by ASTM D3236 of no greater than 7,500 cP and is derived from propylene and at least one monomer selected from the group consisting of hexene, butene, and ethylene.
7 . The hot melt composition of claim 1 , wherein the wax is a paraffin wax.
8 . The hot melt composition of claim 1 wherein the styrene block copolymer has a hydrogenated mid-block.
9 . The hot melt composition of claim 1 wherein the styrene block copolymer is a styrene-isoprene-styrene block copolymer.
10 . The hot melt composition of claim 1 further comprising from 5% by weight to 40% by weight of a tackifying agent.
11 . The hot melt composition of claim 1 being free of a tackifying agent.
12 . The hot melt composition of claim 1 wherein the styrene block copolymer has a melt flow index ASTM D1238 (230° C., 2.16 kg) of from 10 to 300.
13 . The hot melt composition of claim 1 having an elongation of greater than 800%.
14 . The hot melt composition of claim 1 having an elongation of greater than 600% and a maximum tensile stress of at least 1.0 megapascals.
15 . A hot melt composition comprising:
from 15% by weight to 45% by weight of a styrene block copolymer,
from 35% by weight to 75% by weight of a wax having a Congealing Point (ASTM D938) of from 45° C. to 90° C., and
optionally up to 40% by weight of a tackifying agent, wherein the hot melt composition is free of plasticizer.
16 . An absorbent article comprising:
a hot melt composition; and
a core comprising the hot melt composition and absorbent material;
wherein the hot melt composition secures at least a portion of the absorbent core to a material of the absorbent article; and wherein the hot melt composition comprises:
from 15% by weight to 45% by weight of a styrene block copolymer, and
from 25% by weight to 75% by weight of a wax having a Congealing Point (ASTM D938) of from 45° C. to 90° C.
17 . The absorbent article of claim 16 wherein the core comprises less than 10% by weight fluff.
18 . The absorbent article of claim 16 having a total polymer content of no greater than 47% by weight.
19 . The absorbent article of claim 16 wherein the wax is a paraffin wax.
20 . The absorbent article of claim 16 wherein the styrene block copolymer is a styrene-isoprene-styrene block copolymer.