Stabilized polymer compositions and methods of making same

Abstract

The invention relates to stabilizer compositions for polymers such as polyolefin polymers, which decrease a phosphorus based stabilizer content necessary to stabilize the polymer. The premixed stabilizer compositions include an antacid, an organic acid-metal salt, and a primary antioxidant such as a sterically-hindered phenolic compound, a sterically-hindered amine compound, a hydroxylamine compound, and combinations thereof. The premixed stabilizer may further include a portion of the phosphorus based stabilizer content necessary to stabilize the polymer. The invention also relates to a method for the preparation of the stabilized polymer compositions provided by the use thereof.

What is claimed is: 
     
         1 . A stabilized polymer composition comprising:
 a polymer selected from the group consisting of a polyolefin, a styrenic polymer, a poly(meth)acrylate, and combinations thereof,   wherein the polyolefin is selected from the group consisting of polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyisoprene, polybutadiene, polycyclopentene, polynorbornene, polyethylene, high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polypropylene (VLDPE), ultra low density polyethylene (ULDPE), mixture of polypropylene with polyisobutylene, mixtures of polypropylene with polyethylene, ethylene/propylene copolymers, mixtures of linear low density polyethylene with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers, polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA, ethylene-propylene-diene monomer copolymers (EPDM), copolymers of ethylene with higher alpha-olefins, styrene-butadiene copolymers, hydrogenated styrene-butadiene copolymers, styrene-isoprene copolymers, hydrogenated styrene-isoprene copolymers, and combinations thereof; and   about 50 parts per million (ppm) to about 20,000 ppm of a stabilizer composition, comprising:   (a) about 1 wt % to about 60 wt % based on the total weight of the stabilizer composition of an antacid which does not fall under the compounds of (b), selected from the group consisting of metal oxides, metal hydroxides, metal bicarbonates, natural hydrocalumites, synthetic hydrocalumites, pyrocatecholates, zeolites, and combinations thereof;   (b) about 10 wt % to about 69 wt % based on the total weight of the stabilizer composition of an organic acid-metal salt having a general formula M1Ym,   wherein M1 is selected from the group consisting of bismuth, calcium, zinc, magnesium, lithium, sodium, potassium, barium, strontium, aluminum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof;   wherein Y is a conjugate base of an organic acid, having from six to twenty-four carbon atoms, selected from the group consisting of a linear or branched organic acid, a saturated or unsaturated organic acid, a substituted or unsubstituted organic acid, an aliphatic organic acid, an alicyclic organic acid, an oxygen-containing heterocyclic organic acid, dicarboxylic acid, polyprotic carboxylic acids, and combinations thereof; and   wherein m is an integer from 1 to 3; and   (c) about 30 wt % to about 89 wt % based on the total weight of the stabilizer composition of a primary antioxidant selected from the group consisting of sterically hindered phenolic compounds, hindered amine compounds, hydroxylamine compounds, and combinations thereof;   wherein the composition is free or substantially free of phosphite and phosphonite stabilizers, and   wherein at least two of the following conditions under multi pass extrusion of the stabilized polymer composition in a Twin Screw Extruder are met:
 a) the melt flow ratio (MFR) measured according to ASTM D1238 (g/10 min, 190° C., 10 kg) of the stabilized polymer after the fifth pass of a multi pass extrusion is less than 10% higher than the MFR after the first pass or it is lower, 
 b) the yellowness index (YI) of the stabilized polymer measured according to ASTM D6290-13 after one pass is less than 0 and less than the YI of the polymer extruded under the same conditions without stabilizer, 
 c) the YI of the stabilized polymer measured according to ASTM D6290-13 after 1 pass is less than 1, 
 d) the YI of the stabilized polymer measured according to ASTM D6290-13 after 5 passes is less than 0, 
 e) the initial YI of the stabilized polymer measured according to ASTM D6290-13 is below 0 and the YI after 5 passes is below 6, 
 f) the L value of the stabilized polymer measured according to EN ISO 11664-4 after any of 1, 3 or 5 passes is above 74, 
 g) the whiteness index (CIE [D65/10]) after 5 passes is more than 20. 
   
     
     
         2 . The stabilized polymer composition according to  claim 1 , wherein at least three of the conditions a) to g) under multi pass extrusion of the stabilized polymer composition are met. 
     
     
         3 . The stabilized polymer composition according to  claim 1 , wherein the polymer comprises a styrenic polymer, which is selected from polystyrene (PS), acrylonitrile butadiene styrene (ABS) copolymer, or styrene acrylonitrile (SAN) copolymer. 
     
     
         4 . The stabilized polymer composition according to  claim 1 , wherein the polymer comprises a poly(meth)acrylate polymer, which is selected from polyacrylate, polymethacrylate, or copolymers of an acrylate monomer and a methacrylate monomer. 
     
     
         5 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a HDPE and the initial YI of the stabilized polymer is less than −4. 
     
     
         6 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a HDPE and the YI of the stabilized polymer after one pass is less than −1. 
     
     
         7 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a HDPE and the YI of the stabilized polymer after 5 passes is less than 3. 
     
     
         8 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a HDPE and the MFR in g/10 min, 190° C., 10 kg, of the stabilized polymer after the fifth pass of a multi pass extrusion is lower than the MFR after the first pass. 
     
     
         9 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a LLDPE and the YI after one pass is less than −4. 
     
     
         10 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a LLDPE and the YI after 3 passes is less than 5. 
     
     
         11 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a LLDPE and the YI after 5 passes is less than 6. 
     
     
         12 . The stabilized polymer composition according to  claim 1 , wherein the polymer is a LLDPE and the YI after gas fade testing (gas fume chamber, 55° C., 4 days) is less than 1.6. 
     
     
         13 . The stabilized polymer composition according to  claim 9 , wherein the whiteness index after 5 passes is at least 27. 
     
     
         14 . A stabilized polymer composition comprising:
 polypropylene; and   about 50 parts per million (ppm) to about 20,000 ppm of a stabilizer composition, comprising:   (a) about 1 wt % to about 60 wt % based on the total weight of the stabilizer composition of an antacid which does not fall under the compounds of (b) selected from the group consisting of metal oxides, metal hydroxides, metal bicarbonates, natural hydrocalumites, synthetic hydrocalumites, pyrocatecholates, zeolites, and combinations thereof;   (b) about 10 wt % to about 69 wt % based on the total weight of the stabilizer composition of an organic acid-metal salt having a general formula M1Ym,   wherein M1 is selected from the group consisting of bismuth, zinc, magnesium, lithium, sodium, potassium, barium, strontium, aluminum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof;   wherein Y is a conjugate base of an organic acid, having from six to twenty-four carbon atoms, selected from the group consisting of a linear or branched organic acid, a saturated or unsaturated organic acid, a substituted or unsubstituted organic acid, an aliphatic organic acid, an alicyclic organic acid, an oxygen-containing heterocyclic organic acid, dicarboxylic acid, polyprotic carboxylic acids, and combinations thereof; and   wherein m is an integer from 1 to 3; and   (c) about 30 wt % to about 89 wt % based on the total weight of the stabilizer composition of a primary antioxidant selected from the group consisting of sterically hindered phenolic compounds, hindered amine compounds, hydroxylamine compounds, and combinations thereof;   wherein the composition is free or substantially free of phosphite and phosphonite stabilizers; and   wherein at least two of the following conditions under multipass extrusion of the stabilized polymer composition in a Twin Screw Extruder are met:
 a) the melt flow ratio (MFR) measured according to ASTM D1238 (g/10 min, 190° C., 10 kg) of the stabilized polypropylene after the fifth pass of a multi pass extrusion is less than 10% higher than the MFR after the first pass or it is lower, 
 b) the yellowness index (YI) of the stabilized polypropylene measured according to ASTM D6290-13 after one pass is less than 0 and less than the YI of the polypropylene extruded under the same conditions without stabilizer, 
 c) the YI of the stabilized polypropylene measured according to ASTM D6290-13 after 1 pass is less than 1, 
 d) the YI of the stabilized polypropylene measured according to ASTM D6290-13 after 5 passes is less than 0, 
 e) the initial YI of the stabilized polypropylene measured according to ASTM D6290-13 is below 0 and the YI after 5 passes is below 6, 
 f) the L value of the stabilized polypropylene measured according to EN ISO 11664-4 after any of 1, 3 or 5 passes is above 74, 
 g) the whiteness index (CIE [D65/10]) after 5 passes is more than 20, 
 h) the melt flow ratio (MFR) measured according to ASTM D1238 (g/10 min, 190° C., 10 kg) of the stabilized polypropylene after the first pass of a multi pass extrusion is less than the MFR of unstabilized polypropylene, 
 i) the melt flow ratio (MFR) measured according to ASTM D1238 (g/10 min, 190° C., 10 kg) of the stabilized polypropylene after the fifth pass is lower than the MFR of the unstabilized polypropylene after the third pass. 
   
     
     
         15 . The stabilized polymer composition according to  claim 14 , wherein the antacid (a) comprises at least one metal oxide selected from the group consisting of zinc oxide, calcium oxide, magnesium oxide, and combinations thereof, or metal hydroxide selected from the group consisting of calcium hydroxide, magnesium hydroxide, and combinations thereof. 
     
     
         16 . The stabilized polymer composition according to  claim 14 , wherein the antacid (a) comprises at least one of zinc oxide, calcium oxide, magnesium oxide, calcium hydroxide, or magnesium hydroxide, and the organic acid-metal salt (b) comprises zinc stearate or magnesium stearate. 
     
     
         17 . The stabilized polymer composition according to  claim 14 , wherein the antacid (a) comprises at least one metal oxide. 
     
     
         18 . The stabilized polymer composition according to  claim 14 , wherein the primary antioxidant (c) comprises a sterically hindered phenolic compound selected from the group consisting of 2,6-di-tertbutyl-4-methyl phenol; pentaerythrityl-tetrakis(3-(3′,5′-di-tert-butyl-4-hydroxyphenyl)-propionate; octadecyl 3-(3′,5′-di-tert-butyl-4-hydroxyphenyl)propionate; 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenyl)benzene; 2,2′-thiodiethylenebis-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; calcium-(3,5-di-tert-butyl-4-hydroxybenzylmonoethylphosphonate); 1,3,5-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)-isocyanurate; bis-(3,3-bis-(4′-hydroxy-3′-tert-butylphenyl)butanoic acid)-glycolester; 4,4′-thiobis(2-tertbutyl-5-methylphenol); 2,2′-methylene-bis(6-(1-methyl-cyclohexyl)para-cresol); N,N′hexamethylene bis(3,5-di-tertbutyl-4-hydroxy hydrocinnamamide; 2,5,7,8-tetramethyl-2(4′,8′,12′-trimethyltridecyl)chroman-6-ol; 2,2′-ethylidenebis(4,6-di-tert-butylphenol); 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,-6-(1H,3H,5H)-trione; 3,9-bis(1,1-dimethyl-2-(beta-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)ethyl)-2,4,8,10-tetraoxaspiro(5,5)undecane; hydroxybenzene-propanoate); 1,6-hexanediyl-bis(3,5-bis(1,1-dimethylethyl)-4-2,6-di-tert-butyl-4-nonylphenol; 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid triester with 1,3,5-tris(2-hydroxyethyl)-s-triazine-2,4,6(1H,3H, 5H)-trione; 4,4′-butylidenebis(6-tert-butyl-3-methylphenol); 2,2′-methylene bis(4-methyl-6-tert-butylphenol); 2,2-bis(4-(2-(3,5-di-t-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl))propane; triethyleneglycol-bis-(3-tert-butyl-4-hydroxy-5methylphenyl)propionate; 6,6′-di-tertbutyl-2,2′-thiodi-p-cresol; diethyl((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)phosphonate; 4,6-bis(octylthiomethyl)o-cresol; 1,1,3-tris[2-methyl-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-5-tbutylphenyl]butane; butylated reaction product of p-cresol and dicyclopentadiene; and combinations thereof. 
     
     
         19 . The stabilized polymer composition according to  claim 14 , wherein the stabilized polymer further comprises at least one of an anti-static agent, an anti-fogging agent, an acid scavenger, a blowing agent, a cling agent, a lubricant, a nucleating agent, an anti-blocking agent, a filler, a flame retardant, a compatibilizer, or a cross-linking agent. 
     
     
         20 . The stabilized polymer composition according to  claim 14 , wherein the stabilizer composition is present in an amount of from about 500 ppm to about 8,000 ppm. 
     
     
         21 . The stabilized polymer composition according to  claim 14 , wherein the stabilized polymer composition is provided by a process comprising:
 (1) preparing a first premixture comprising the antacid (a) and the organic acid-metal salt (b) or the primary antioxidant (c);   (2) intimately mixing the first premixture obtained from step (1) at an elevated temperature sufficient to provide a molten mixture comprising a dispersion of the antacid (a) in the organic acid-metal salt (b) or the primary antioxidant (c) or both;   (3) optionally, lowering a temperature of the molten mixture to provide a second premixture in solid form; and   (4) combining the molten mixture of step (2) or the second premixture in solid form of step (3) with the polymer and at least one additional ingredient of (b) or (c), if not already present.   
     
     
         22 . A stabilized polymer composition comprising:
 a polymer selected from the group consisting of a polyolefin, a styrenic polymer, a poly(meth)acrylate, and combinations thereof, and   about 50 parts per million (ppm) to about 20,000 ppm of a stabilizer composition, comprising:   (a) about 1 wt % to about 60 wt % based on the total weight of the stabilizer composition of an antacid which does not fall under the compounds of (b), selected from the group consisting of metal oxides, metal hydroxides, metal bicarbonates, natural hydrocalumites, synthetic hydrocalumites, pyrocatecholates, zeolites, and combinations thereof;   (b) about 10 wt % to about 69 wt % based on the total weight of the stabilizer composition of an organic acid-metal salt having a general formula M1Ym,   wherein M1 is selected from the group consisting of bismuth, zinc, magnesium, lithium, sodium, potassium, barium, strontium, aluminum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof;   wherein Y is a conjugate base of an organic acid, having from six to twenty-four carbon atoms, selected from the group consisting of a linear or branched organic acid, a saturated or unsaturated organic acid, a substituted or unsubstituted organic acid, an aliphatic organic acid, an alicyclic organic acid, an oxygen-containing heterocyclic organic acid, dicarboxylic acid, polyprotic carboxylic acids, and combinations thereof; and   wherein m is an integer from 1 to 3;   (c) about 30 wt % to about 89 wt % based on the total weight of the stabilizer composition of a primary antioxidant selected from the group consisting of sterically hindered phenolic compounds, hindered amine compounds, hydroxylamine compounds, and combinations thereof; and   wherein the composition is free or substantially free of phosphite and phosphonite stabilizers; and   wherein the stabilized polymer composition is provided by a process comprising:
 (1) preparing a first premixture comprising the antacid (a) and the organic acid-metal salt (b) or the primary antioxidant (c) or both; 
 (2) intimately mixing the first premixture obtained from step (1) at an elevated temperature sufficient to provide a softened or molten mixture comprising a dispersion of the antacid (a) in the organic acid-metal salt (b) or the primary antioxidant (c) or both; 
 (3) optionally, lowering a temperature of the molten mixture to provide a second premixture in solid form; and 
 (4) combining the molten mixture of step (2) or the second premixture in solid form of step (3) with the polymer and at least one additional ingredient of (b) or (c), if not already present. 
   
     
     
         23 . A stabilized polymer composition comprising:
 a polymer selected from the group consisting of a polyolefin, a styrenic polymer, a poly(meth)acrylate, and combinations thereof; and   about 50 parts per million (ppm) to about 20,000 ppm of a stabilizer composition, comprising:   (a) about 1 wt % to about 60 wt % based on the total weight of the stabilizer composition of an antacid which does not fall under the compounds of (b), selected from the group consisting of metal oxides, metal hydroxides, metal bicarbonates, natural hydrocalumites, synthetic hydrocalumites, pyrocatecholates, zeolites, and combinations thereof;   (b) about 10 wt % to about 69 wt % based on the total weight of the stabilizer composition of an organic acid-metal salt having a general formula M1Ym,   wherein M1 is selected from the group consisting of bismuth, zinc, magnesium, lithium, sodium, potassium, barium, strontium, aluminum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof;   wherein Y is a conjugate base of an organic acid, having from six to twenty-four carbon atoms, selected from the group consisting of a linear or branched organic acid, a saturated or unsaturated organic acid, a substituted or unsubstituted organic acid, an aliphatic organic acid, an alicyclic organic acid, an oxygen-containing heterocyclic organic acid, dicarboxylic acid, polyprotic carboxylic acids, and combinations thereof; and   wherein m is an integer from 1 to 3; and   (c) about 30 wt % to about 89 wt % based on the total weight of the stabilizer composition of a primary antioxidant selected from the group consisting of sterically hindered phenolic compounds, hindered amine compounds, hydroxylamine compounds, and combinations thereof;   wherein the composition is free or substantially free of phosphite and phosphonite stabilizers;   wherein a mixture of at least (a) and (b) of the stabilizer composition has been subjected to a temperature of more than 100° C. before admixture with the polymer to be stabilized.   
     
     
         24 . A method for preparing a stabilized polymer composition comprising
 a polymer selected from the group consisting of a polyolefin, a styrenic polymer, a poly(meth)acrylate, and combinations thereof; and   
       about 50 parts per million (ppm) to about 20,000 ppm of a stabilizer composition, comprising:
 (a) about 1 wt % to about 60 wt % based on the total weight of the stabilizer composition of an antacid which does not fall under the compounds of (b), selected from the group consisting of metal oxides, metal hydroxides, metal bicarbonates, natural hydrocalumites, synthetic hydrocalumites, pyrocatecholates, zeolites, and combinations thereof; 
 (b) about 10 wt % to about 69 wt % based on the total weight of the stabilizer composition of an organic acid-metal salt having a general formula M1Ym, 
 wherein M1 is selected from the group consisting of bismuth, calcium, zinc, magnesium, lithium, sodium, potassium, barium, strontium, aluminum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof; 
 wherein Y is a conjugate base of an organic acid, having from six to twenty-four carbon atoms, selected from the group consisting of a linear or branched organic acid, a saturated or unsaturated organic acid, a substituted or unsubstituted organic acid, an aliphatic organic acid, an alicyclic organic acid, an oxygen-containing heterocyclic organic acid, dicarboxylic acid, polyprotic carboxylic acids, and combinations thereof; and 
 wherein m is an integer from 1 to 3; and 
 (c) about 30 wt % to about 89 wt % based on the total weight of the stabilizer composition of a primary antioxidant selected from the group consisting of sterically hindered phenolic compounds, hindered amine compounds, hydroxylamine compounds, and combinations thereof; 
 wherein the composition is free or substantially free of phosphite and phosphonite stabilizers; 
 wherein the method comprises:
 (1) preparing a first premixture comprising the antacid (a) and the organic acid-metal salt (b) or the primary antioxidant (c) or both; 
 (2) intimately mixing the first premixture obtained from step (1) at an elevated temperature sufficient to provide a molten mixture comprising a dispersion of the antacid (a) in the organic acid-metal salt (b) or the primary antioxidant (c) or both; 
 (3) optionally, lowering a temperature of the molten mixture to provide a second premixture in solid form; and 
 (4) combining the molten mixture of step (2) or the second premixture in solid form of step (3) with the polymer and at least one additional ingredient of (b) or (c), if not already present. 
 
 
     
     
         25 . The method of  claim 24 , wherein the first premixture comprises the antacid (a) and the organic acid-metal salt (b), which provides the molten mixture comprising a dispersion of the antacid in the organic acid-metal salt. 
     
     
         26 . The method of  claim 25 , wherein the method comprises step (3) and wherein step (3) of the method includes lowering the temperature of the molten mixture to provide the second premixture in solid form comprising a dispersion of the antacid (a) in the organic acid-metal salt (b). 
     
     
         27 . The method of  claim 24 , wherein the first premixture comprises the antacid (a) and the primary antioxidant (c), which provides the molten mixture comprising a dispersion of the antacid (a) in the primary antioxidant (c). 
     
     
         28 . The method of  claim 27 , wherein the method comprises step (3) and wherein step (3) of the method includes lowering the temperature of the molten mixture to provide the second premixture in solid form comprising a dispersion of the antacid (a) in the primary antioxidant (c). 
     
     
         29 . The method of  claim 25 , wherein the second premixture in solid form and the primary antioxidant (c) is mixed with the polymer.