Hot melt adhesive
Disclosed is a hot melt adhesive comprising: (A) a copolymer of ethylene with an olefin having 3 to 20 carbon atoms; (B) an ethylene-carboxylic acid ester copolymer; and (C) a tackifying resin, wherein the (B) ethylene-carboxylic acid ester copolymer comprises (B1) an ethylene-(meth)acrylic acid ester copolymer containing a structural unit derived from the (meth)acrylic acid ester in an amount of 2 to 24% by mass.
1 . A hot melt adhesive composition comprising:
a copolymer of ethylene and an olefin, the olefin having 3 to 20 carbon atoms;
an ethylene-carboxylic acid ester copolymer;
a tackifying resin; and
a wax, wherein:
the ethylene-carboxylic acid ester copolymer comprises an ethylene-(meth)acrylic acid ester copolymer having a structural unit derived from methyl methacrylate, the structural unit derived from methyl methacrylate being present in an amount of from 2 parts to 20 parts by mass, based on 100 parts by mass of the ethylene-(meth)acrylic acid ester copolymer,
the copolymer is present in an amount of from 20 to 50 parts by mass, based on 100 parts by total mass of the copolymer, the ethylene-carboxylic acid ester copolymer, and the tackifying resin,
the ethylene-(meth)acrylic acid ester copolymer is present in an amount of from 1 to 10 parts by mass, based on 100 parts by total mass of the copolymer, the ethylene-carboxylic acid ester copolymer, and the tackifying resin, and
the tackifying resin is present in an amount of from 40 to 55 parts by mass, based on 100 parts by total mass of the copolymer, the ethylene-carboxylic acid ester copolymer, and the tackifying resin.
2 . The composition of claim 1 , wherein the ethylene-(meth)acrylic acid ester copolymer further comprises at least one copolymer selected from the group consisting of ethylene-methyl methacrylate copolymers, ethylene-butyl acrylate copolymers, and ethylene-ethyl acrylate copolymers.
3 . The composition of claim 1 , wherein the tackifying resin comprises a partially hydrogenated tackifying resin and a completely hydrogenated tackifying resin.
4 . A paper product comprising the hot melt adhesive composition of claim 1 .
5 . The composition of claim 1 , wherein the copolymer is a metallocene-based copolymer of ethylene.
6 . The composition of claim 1 , wherein the ethylene-(meth)acrylic acid ester copolymer has a melt flow rate of from 1 g/10 min to about 35 g/10 min, measured at 190° C. with a 2.16 kg load in accordance with JIS K7210.
7 . The composition of claim 1 , wherein the tackifying resin comprises a hydrocarbon resin having a softening point of lower than 120° C. and a hydrocarbon resin having a softening point of greater than 120° C.
8 . The composition of claim 1 , wherein the melting point of the wax is from about 70° C. to about 120° C.
9 . The composition of claim 1 , wherein the wax is selected from the group consisting of Fischer-Tropsch waxes, paraffin waxes, microcrystalline waxes, polyethylene waxes, polypropylene waxes, and any combination thereof.
10 . The composition of claim 1 , wherein the ethylene-carboxylic acid ester copolymer further comprises another ethylene-(meth)acrylic acid ester copolymer having a structural unit derived from methyl methacrylate, the structural unit derived from methyl methacrylate being present in an amount less than 2 parts by mass, based on 100 parts by mass of the another ethylene-(meth)acrylic acid ester copolymer.
11 . The composition of claim 1 , wherein the ethylene-carboxylic acid ester copolymer further comprises another ethylene-(meth)acrylic acid ester copolymer having a structural unit derived from methyl methacrylate, the structural unit derived from methyl methacrylate being present in an amount greater than 24 parts by mass, based on 100 parts by mass of the another ethylene-(meth)acrylic acid ester copolymer.
12 . The composition of claim 1 , further comprising at least one additive selected from the group consisting of a plasticizer, a stabilizer, and a filler.
13 . The composition of claim 12 , wherein the stabilizer is selected from the group consisting of a phenolic antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant.
14 . A paper product comprising:
a paper substrate; and
the hot melt adhesive composition of claim 1 applied to the paper substrate.
15 . The composition of claim 1 , wherein the copolymer is selected from the group consisting of an ethylene-octene copolymer, ethylene-octene copolymer, an ethylene-propylene copolymer, and an ethylene-hexene copolymer.