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US 12,715,991 B2Granted
Recyclable extrusion blow molded articles from blends of copolyesters and recycled PET
AssigneeEastman Chemical Company
InventorsMark Allan Treece, Michael Gage Armstrong, Robert William Seymour
Life of this patent
Estimating the term…
Abstract
The present disclosure relates to recyclable extrusion blow molded articles made from blends of recycled PET and copolyester compositions which comprise residues of terephthalic acid, neopentyl glycol (NPG), 1,4-cyclohexanedimethanol (CHDM), ethylene glycol (EG), and/or 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, in certain compositional ranges that are <4 mm thickness, have a high level of recycled PET content, have low haze and are recyclable in a PET stream.
Claims8
A method of making a recyclable, extrusion blow-molded article comprising:
- (A) compounding a rPET/copolyester blend which comprises:
- (1) 20-80 wt % of recycled polyethylene terephthalate (rPET);
- and
- (2) 20-80 wt % of at least one copolyester which comprises:
- (a) a dicarboxylic acid component comprising:
- i) 70 to 100 mole % of terephthalic acid residues, dimethyl terephthalic acid, and/or isophthalic acid;
- and
- ii) 0 to 30 mole % of aromatic and/or aliphatic dicarboxylic acid residues having up to 20 carbon atoms;
- and;
- iii) 0 to 5 mole % of a branching monomer;
- and
- (b) a glycol component comprising:
- i) 15 to 35 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues;
- and
- v) 65 to 85 mole % of ethylene glycol residues;
- and
- vi) 0 to 5 mole % of a branching monomer;
- and
- wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %;
- and
- (3) 0.05 to 5 weight % of a chain extending agent based on the weight of the blend;
- and
- wherein the blend has 1-15 wt % total comonomer content from glycols and acids other than ethylene glycol (EG), terephthalic acid (TPA), or dimethyl terephthalate (DMT), and wherein the blend is compounded at a temperature of 260-320° C., and wherein the method further comprises drying the rPET at temperature of up to 150° C. and the copolyester at temperature of up to 65° C. before compounding;
- (B) pelletizing the compounded blend;
- (C) drying the compounded blend at a temperature of 60-160° C., and optionally crystallizing the compounded blend at 120-180° C. before drying;
- (D) melting the compounded blend in an extruder and extruding the molten composition through a die to form a tube or parison of molten polymer;
- and
- (E) clamping a mold having the desired finished shape around the parison;
- (F) blowing air into the parison, causing it to stretch and expand to fill the mold;
- (G) cooling the molded article and ejecting the resulting article from the mold;
- and
- (H) removing excess plastic from the article;
- wherein the article is transparent and/or has a haze value of less than 20%;
- wherein the article has a melting temperature (Tm) of 230-250° C.;
- wherein the article has an enthalpy of melting (Hm) greater than 0.20 cal/g;
- wherein the inherent viscosity of the copolyester is 0.50 to 1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.;
- wherein the copolyester has a Tg of 70 to 115° C.;
- wherein the rPET/copolyester blend has a melt viscosity at 1 rad/s and 260° C. of 10,000 to 120,000 poise;
- and wherein the article has a thickness of less than 4 mm, and wherein the article is recyclable in a PET recycle stream.
36 more elements
A method of making a recyclable, extrusion blow-molded article comprising:
- (A) compounding a rPET/copolyester blend which comprises:
- (1) 20-80 wt % of recycled polyethylene terephthalate (rPET);
- and
- (2) 20-80 wt % of at least one copolyester which comprises:
- (a) a dicarboxylic acid component comprising:
- i) 70 to 100 mole % of terephthalic acid residues, dimethyl terephthalic acid, and/or isophthalic acid;
- and
- ii) 0 to 30 mole % of aromatic and/or aliphatic dicarboxylic acid residues having up to 20 carbon atoms;
- and;
- iii) 0 to 5 mole % of a branching monomer;
- and
- (b) a glycol component comprising:
- i) 30 to less than 50 mole % of 1,4-cyclohexanedimethanol residues;
- ii) 50 to 70 mole % of ethylene glycol residues;
- iii) 0 to 5 mole % of a branching monomer;
- and
- wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %;
- and
- (3) 0.05 to 5 weight % of a chain extending agent based on the weight of the blend;
- and
- wherein the blend has 1-15 wt % total comonomer content from glycols and acids other than ethylene glycol (EG), terephthalic acid (TPA), or dimethyl terephthalate (DMT), and wherein the blend is compounded at a temperature of 260-320° C., and wherein the method further comprises drying the rPET at temperature of up to 150° C. and the copolyester at temperature of up to 65° C. before compounding;
- (B) pelletizing the compounded blend;
- (C) drying the compounded blend at a temperature of 60-160° C., and optionally crystallizing the compounded blend at 120-180° C. before drying;
- (D) melting the compounded blend in an extruder and extruding the molten composition through a die to form a tube or parison of molten polymer;
- and
- (E) clamping a mold having the desired finished shape around the parison;
- (F) blowing air into the parison, causing it to stretch and expand to fill the mold;
- (G) cooling the molded article and ejecting the resulting article from the mold;
- and
- (H) removing excess plastic from the article;
- wherein the article is transparent and/or has a haze value of less than 20%;
- wherein the article has a melting temperature (Tm) of 230-250° C.;
- wherein the article has an enthalpy of melting (Hm) greater than 0.20 cal/g;
- wherein the inherent viscosity of the copolyester is 0.50 to 1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.;
- wherein the copolyester has a Tg of 70 to 115° C.;
- wherein the rPET/copolyester blend has a melt viscosity at 1 rad/s and 260° C. of 10,000 to 120,000 poise;
- and wherein the article has a thickness of less than 4 mm, and wherein the article is recyclable in a PET recycle stream.
34 more elements
Dependencies are inferred from the claim text.