Oxygen scavenging copolymers made from cyclic aliphatic monomers
View Patent ↗A method and system for oxygen molecule scavenging is disclosed. The system employs as a novel copolymer as the reducing agent for oxygen molecules. The copolymer is the polymerization product of cyclic aliphatic monomer and unsaturated functional polymer.
1. A thermoplastic compound, comprising: (a) polyethylene terephthalate matrix; and (b) a copolymer of lactide monomer and hydroxyl-terminated functionalized polybutadiene;
wherein the lactide monomer is present in the copolymer in a weight percent ranging from about 30% to about 70% of the copolymer and wherein the hydroxyl-terminated functionalized polybutadiene is present in the copolymer in a weight percent ranging from about 30% to about 70% of the copolymer; and
wherein the copolymer has a weight average molecular weight (Mw) of about 15,000-20,000, a number average molecular weight (Mn) of about 8,500-10,000, and a polydispersity of from about 1.8 to about 2.2, all as measured via Gel Permeation Chromatography (GPC) using polystyrene as a test reference.
2. The compound of claim 1 , further comprising a catalyst for the copolymer functioning as a reducing agent for oxygen molecules.
3. The compound of claim 1 , further comprising a functional additive selected from the group consisting of adhesion promoters; biocides, anti-fogging agents; anti-static agents; bonding, blowing and foaming agents; dispersants; fillers and extenders; fire and flame retardants and smoke suppressants; impact modifiers; initiators; lubricants; micas; pigments, colorants and dyes; plasticizers; processing aids; release agents; silanes, titanates and zirconates; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; and combinations of them.
4. The compound of claim 1 , wherein the copolymer comprises from about 0.1 to about 3 percent by weight of the compound.
5. The compound of claim 1 , wherein the compound is in the form of a thermoplastic article.
6. The compound of claim 5 , wherein the article is a bottle pre-form.
7. The compound of claim 5 , wherein the article is a blow-molded bottle.
8. The compound of claim 7 , wherein the bottle contains a perishable food or beverage susceptible to oxidation.
9. A method for scavenging for oxygen within a thermoplastic article, comprising:
(a) mixing a reducing agent for oxygen molecules into a thermoplastic compound and
(b) forming an article from the thermoplastic compound,
wherein the reducing agent is a copolymer of lactide monomer and hydroxyl-terminated functionalized polybutadiene, and
wherein the copolymer has carbon-carbon unsaturated bonds susceptible to reaction with oxygen molecules;
wherein the lactide monomer is present in the copolymer in a weight percent ranging from about 30% to about 70% of the copolymer and wherein the hydroxyl-terminated functionalized polybutadiene is present in the copolymer in a weight percent ranging from about 30% to about 70% of the copolymer; and
wherein the copolymer has a weight average molecular weight (Mw) of about 15,000-20,000, a number average molecular weight (Mn) of about 8,500-10,000, and a polydispersity of from about 1.8 to about 2.2, all as measured via Gel Permeation Chromatography (GPC) using polystyrene as a test reference.
10. The method of claim 9 , wherein step (a) also includes mixing a catalyst into the thermoplastic compound.
11. The method of claim 9 , wherein the copolymer reduces an oxygen molecule by reaction with a carbon-carbon unsaturated bond, thereby scavenging the oxygen molecule from the article.