Ionomer compositions
Described in embodiments herein are ionomers comprising a neutralized blend of an ethylene acid copolymer, an aliphatic and a mono-functional organic acid. The blend includes from 40 wt % to 95 wt % of the ethylene acid copolymer, from 5 to 50 wt % of the aliphatic, mono-functional organic acid, based on the total weight of the blend. The ethylene acid copolymer is the polymerized reaction product of ethylene, from 1 to 25 wt % of monocarboxylic acid and from 1 to 40 wt % of alkyl acrylate, based on the total weight of the monomers present in the ethylene acid copolymer. The aliphatic, mono-functional organic acid has fewer than 36 carbon atoms. In various embodiments, at least 70 mole % of total acid units are neutralized with both a trivalent cation and either a mono- or di-valent cation.
1. A foam comprising an ionomer, wherein the ionomer comprises a neutralized blend of an ethylene acid copolymer and an aliphatic, mono-functional organic acid, wherein the blend consists of:
from 40 to 95 wt % of the ethylene acid copolymer, based on the total weight of the blend, the ethylene acid copolymer being the polymerized reaction product of:
ethylene, and
from 1 to 25 wt % of monocarboxylic acid, based on the total weight of monomer present in the ethylene acid copolymer; and
from 1 to 40 wt % of softening comonomer, based on the total weight of monomer present in the ethylene acid copolymer;
from 5 to 50 wt % of the aliphatic, mono-functional organic acid, based on the total weight of the blend, wherein the aliphatic, mono-functional organic acid has fewer than 36 carbon atoms; and
from 0 wt. % to 40 wt. % of additives selected from the group consisting of plasticizers, stabilizers, hydrolytic stabilizers, primary and secondary antioxidants, ultraviolet light absorbers, anti-static agents, dyes, pigments coloring agents, inorganic fillers, fire-retardants, lubricants, reinforcing agents, synthetic fiber or pulp, foaming or blowing agents, processing aids, slip additives, antiblock agents, release agents, tackifying resins, and inorganic fillers;
wherein at least 70 mole % of total acid units are neutralized with a cation source comprising (a) a trivalent cation and (b) either a mono- or di-valent cation; and
wherein at least 70 mol. % of the total acid units are neutralized with the trivalent cations.
2. The foam of claim 1 , wherein the monocarboxylic acid comprises one or more of acrylic acid, methacrylic acid, or combinations thereof.
3. The foam of claim 1 , wherein the softening comonomer is an alkyl acrylate selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate or iso-butyl acrylate, or combinations thereof.
4. The foam of claim 1 , wherein the ionomer has a melt index, I 2 , of 0.1 to 30 g/10 min, as determined in accordance with ASTM D1238 (220° C., 2.16 kg).
5. The foam of claim 1 , wherein the ionomer has a density of 0.920 to 0.980 g/cc.
6. The foam of claim 1 , wherein the mono- or di-valent cation is selected from the group consisting of a magnesium, sodium, zinc, lithium, and potassium cation.
7. The foam of claim 1 , wherein the blend comprises from 60 to 80 wt % of the ethylene acid copolymer.
8. The foam of claim 7 , wherein the blend comprises from 15 to 35 wt % of the aliphatic, mono-functional organic acid.
9. The foam of claim 1 , wherein at least 90 mole % of total acid units are neutralized with a cation source comprising (a) a trivalent cation and (b) either a mono- or di-valent cation.
10. The foam of claim 9 , wherein 100 mole % of the total acid units are neutralized using an amount of the cation source in excess of the amount required to neutralize 100% of the total acid units.
11. The foam of claim 1 , wherein the foam exhibits a creep resistance as defined by a dimensional change of less than 50% at 100° C. under a load of 30 g at a stress of 46 kPa after 30 minutes.
12. The foam of claim 1 , wherein the foam exhibits a creep resistance as defined by a dimensional change of less than 200% at 100° C. under a load of 100 g at a stress of 150 kPa after 30 minutes.
13. The foam of claim 1 , wherein the foam exhibits a creep resistance as defined by a dimensional change of less than 15% at 100° C. under a load of 100 g at a stress of 150 kPa after 30 minutes.
14. The foam of claim 1 , wherein the foam exhibits a creep resistance as defined by a dimensional change of less than 500% at 50° C. under a load of 400 g at a stress of 600 kPa after 96 hours.
15. The foam of claim 1 , wherein at least 100 mole % of total acid units are neutralized with a cation source comprising (a) a trivalent cation and (b) either a mono- or di-valent cation.
16. The foam of claim 1 , wherein at least 80 mol. (Original) % of the total acid units are neutralized with the trivalent cations.
17. The foam of claim 1 , wherein at least 95 mol. % of the total acid units are neutralized with the trivalent cations.
18. The foam of claim 17 , wherein from 10 to 55 mol. % of the total acid units are neutralized with the divalent cations.
19. A foam comprising an ionomer, wherein the ionomer comprises a neutralized blend of an ethylene acid copolymer and an aliphatic, mono-functional organic acid, wherein the blend comprises:
from 40 to 95 wt % of the ethylene acid copolymer, based on the total weight of the blend, the ethylene acid copolymer being the polymerized reaction product of:
ethylene, and
from 1 to 25 wt % of monocarboxylic acid, based on the total weight of monomer present in the ethylene acid copolymer; and
from 1 to 40 wt % of softening comonomer, based on the total weight of monomer present in the ethylene acid copolymer;
from 5 to 50 wt % of the aliphatic, mono-functional organic acid, based on the total weight of the blend, wherein the aliphatic, mono-functional organic acid has fewer than 36 carbon atoms;
wherein:
at least 90 mole % of total acid units are neutralized with a cation source comprising (a) a trivalent cation and (b) either a mono- or di-valent cation; and
at least 80 mol. % of the total acid units are neutralized with the trivalent cations.