Fluorine-free polymer processing aids including polyethylene glycols
Provided herein are polymer compositions comprising a polymer and polyethylene glycol (PEG)-based polymer processing aid (PPA). The polyethylene glycol can have molecular weight less than 40,000 g/mol. The polymer can be a C 2 -C 6 olefin homopolymer or a copolymer of two or more C 2 -C 20 α-olefins, and the polymer composition can take the form of polymer pellets; a polymer melt; reactor-grade polymer granules and/or polymer slurries; or other form of polymer composition containing the PPA and optionally one or more other additives. The polymer composition is preferably free or substantially free of fluorine, including fluoropolymer-based PPAs.
1. A blown film made from a polymer composition,
wherein the polymer composition comprises polymer pellets that consist of:
a metallocene-catalyzed linear low density polyethylene (LLDPE) copolymer comprising units derived from ethylene and units derived from one or more C 3 to C 20 α-olefin comonomers and having density within the range from 0.905 to 0.935 g/cm 3 ;
from 800 to 2,500 ppm (on the basis of mass of the polymer composition) of one or more polyethylene glycols each having weight average molecular weight (Mw) within the range from 7,000 to 9,500 g/mol; and
optionally, one or more additives selected from the group consisting of fillers, antioxidants, phosphites, anti-cling additives, tackifiers, UV stabilizers, heat stabilizers, release agents, anti-static agents, waxes, and combinations thereof;
wherein the polymer pellets are formed by a process comprising melt-blending the one or more polyethylene glycols and the copolymer at sufficiently high temperature and/or specific energy input to achieve homogenization among the one or more polyethylene glycols and the copolymer, such that the polymer pellets include the one or more polyethylene glycols homogenously distributed among the copolymer; and
wherein the blown film has one or more of:
i. 1% secant modulus (MD) within +/−5% of the value (psi) of a film that is made using a fluoropolymer-based PPA instead of the one or more polyethylene glycols, but is otherwise identical;
ii. Elmendorf tear (MD) within +/−10% of the value (g) of a film that is made using a fluoropolymer-based PPA instead of the one or more polyethylene glycols, but is otherwise identical:
iii. Total haze within +/−25% of the value (in %) of a film that is made using a fluoropolymer-based PPA instead of the one or more polyethylene glycols, but is otherwise identical, and/or total haze less than 6%;
iv. Gloss (MD) within +/−12% of the value (in GU) of a film that is made using a fluoropolymer-based PPA instead of the one or more polyethylene glycols, but is otherwise identical; and
v. Dart within +/−1%, of the value (g) of a film that is made using a fluoropolymer-based PPA instead of the one or more polyethylene glycols, but is otherwise identical.
2. The blown film of claim 1 , wherein the polymer composition has from 800 to 2,000 ppm total of polyethylene glycol.
3. The blown film of claim 1 , wherein each polyethylene glycol of the has Mw within the range from 7,500 to 8,500 g/mol.
4. The blown film of claim 1 , wherein the copolymer has melt index (ASTM D1238 at 190° C., 2.16 kg loading) within the range from 0.1 to 5.0 g/10 min.
5. The blown film of claim 4 , wherein the copolymer is metallocene-catalyzed linear low density polyethylene (mLLDPE), comprising units derived from ethylene and units derived from 1-butene, 1-hexene, or 1-octene.
6. The blown film of claim 5 , wherein:
the copolymer has melt index within the range from 0.1 to less than 0.45 g/10 min (190° C., 2.16 kg); and
the polymer composition has from 800 ppm to 1100 ppm of polyethylene glycol.
7. The blown film of claim 5 , wherein the copolymer has density within the range from 0.910 to 0.930 g/cm 3 and melt index (ASTM D1238 at 190° C., 2.16 kg loading) within the range from 0.1 to 1.5 g/10 min.
8. The blown film of claim 1 , having all of i., ii., iii., iv., and v.