Hot melt pressure sensitive adhesives

1. A hot melt pressure sensitive adhesive comprising:

(a) about 10 to about 50% by weight of at least one polymer;

(b) about 5 to about 50% by weight of isoparaffinic oil having a glass transition temperature at or below about −75° C. for amorphous components in said isoparaffinic oil and wherein a carbon-13 nmr spectra of said isoparaffinic oil shows greater than 95 molar percent aliphatic carbon atoms; and

(c) about 30 to about 65% by weight of at least one tackifying resin.

2. The hot melt pressure sensitive adhesive of claim 1 wherein said isoparaffinic oil has a glass transition temperature at or below about −80° C. for amorphous components in said isoparaffinic oil.

3. The hot melt pressure sensitive adhesive of claim 1 wherein said isoparaffinic oil has a weight average molecular weight of about 390 to about 470.

4. The hot melt pressure sensitive adhesive of claim 1 wherein a carbon-13 nmr spectra of said isoparaffinic oil shows substantially all aliphatic carbon atoms.

5. The hot melt pressure sensitive adhesive of claim 1 wherein said isoparaffinic oil has:

a glass transition temperature at or below about −75° C. for amorphous components in said isoparaffinic oil;

a weight average molecular weight of about 390 to 470; and

a carbon-13 nmr spectra of said isoparaffinic oil shows substantially all aliphatic carbon atoms.

6. The hot melt pressure sensitive adhesive of claim 5 wherein said glass transition temperature is at or below about −80° C. for amorphous components in said isoparaffinic oil.

7. The hot melt pressure sensitive adhesive of claim 1 further comprising up to about 2.0% by weight of at least one stabilizer.

8. The hot melt pressure sensitive adhesive of claim 7 further comprising up to about 10% by weight of at least one filler or wax.

9. The hot melt pressure sensitive adhesive of claim 1 additionally comprising at least one additional oil, said oil being a naphthenic oil, a paraffinic oil, a phthalate or adipate ester, an oligomer of polypropylene, a polybutene, a polyisoprene, a hydrogenated polyisoprene or polybutadiene, a benzoate ester, a vegetable oil or an animal oil.

10. The hot melt pressure sensitive adhesive of claim 8 wherein said wax is a paraffin wax, a microcrystalline wax, a Fischer-Tropsch wax, a polyethylene wax, an ethylene vinyl acetate wax, an oxidized polyethylene wax, a hydrogenated castor oil wax, or mixtures thereof.

11. The hot melt pressure sensitive adhesive of claim 1 wherein said isoparaffinic oil has a Cp value of greater than about 75%, a flash point of greater than 240° C., and a pour point of less than about −15° C.

12. The hot melt pressure sensitive adhesive of claim 1 wherein said tackifying resin comprises at least one of aliphatic petroleum resins or the hydrogenated derivatives thereof, aromatic petroleum resins or the hydrogenated derivatives thereof, aliphatic/aromatic petroleum resins or the hydrogenated derivatives thereof, hydrocarbon resins, styrene resins, alpha-methyl styrene resins, polyterpene resins, copolymers and terpolymers of natural terpene resins, pentaerythritol esters of wood, gum, and tall-oil rosins, glycerol esters of wood, gum, and tall-oil rosins, or mixed esters of rosins.

13. The hot melt pressure sensitive adhesive of claim 7 wherein the stabilizer is an antioxidant.

14. The hot melt pressure sensitive adhesive of claim 13 wherein the antioxidant is a hindered phenol or a phosphite.

15. The hot melt pressure sensitive adhesive of claim 1 wherein said isoparaffinic oil has a Chemical Abstracts number of 72623-87-1.

16. A hot melt construction adhesive comprising:

(a) about 5 to about 20% by weight of a linear styrene-butadiene A-B-A-B-A multi-block copolymer containing at least about 25 weight percent styrene;

(b) about 5 to about 20% by weight of a linear styrene-isoprene A-B-A tri-block copolymer containing at least about 25 percent by weight of styrene;

(c) about 40 to about 65% by weight of at least one tackifying resin;

(d) about 10 to about 30% by weight of isoparaffinic oil having a glass transition temperature at or below about −75° C. for amorphous components in said isoparaffinic oil and wherein a carbon-13 nm r spectra of said isoparaffinic oil shows greater than 95 molar percent aliphatic carbon atoms;

(e) up to about 10% by weight of at least one wax; and

(f) up to about 2.0% by weight of at least one stabilizer;

said adhesive having a viscosity no greater than about 6,000 mPa·s at about 140° C., a shear adhesion failure temperature of at least about 65° C., and a static shear time to failure of no less than about 25 hours at about 23° C.