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US-20260125539-A1 - EXTRUSION PROCESS AIDS FOR POLYOLEFINS

US20260125539A1US 20260125539 A1US20260125539 A1US 20260125539A1US-20260125539-A1

Abstract

Organic molecules with free acid groups and a molecular weight of greater than 140 g/mol used in combination with surfactants, are used as processing aids in the formation of extrudates and other molded materials. The compositions of this invention can be used as defined herein, or can be used with prior art processing aids, depending on the end use application. The novel materials and processes provide a useful alternative to the sole use of fluorine-based polymer processing aids.

Inventors

  • Veerag Mehta
  • Vikas Mehta

Assignees

  • Veerag Mehta
  • Vikas Mehta

Dates

Publication Date
20260507
Application Date
20241105

Claims (20)

  1. 1 . A process for preparing a thermoplastic composition extrudate, the process comprising: A) extruding a thermoplastic composition in a melt extrusion process, the thermoplastic composition comprising a polyolefin selected from the group comprising: a) a linear polyolefin, b) a branched polyolefin, c) a homopolymer of polyolefin, d) a copolymer polyolefin, e) a terpolymer polyolefin, and f) mixtures of a)-e), and from 0.01% to 4% based on the weight of the polyolefin of a material selected from the group consisting of a linear carbon-based material, a branched carbon-based material, and mixtures thereof, each having a molecular weight greater than 140 g/mol and each having an acid value of 0.1 mg/KOH or above with an acid functionality on a backbone thereof consisting of one or multiple functional acid groups selected from the group consisting of: i) phosphoric acid, (ii) phosphoric acid derivatives, (iii) sulphonic acid, iv) sulphonic acid derivatives, v) carboxylic acid, vi) carboxylic acid derivatives, vii) dicarboxylic acid, viii)dicarboxylic acid derivatives, ix) tricarboxylic acid, x) tricarboxylic acid derivatives, xi) acrylic acid, xii) acid modified acrylic acid derivatives, xiii)carbonic acid, xiv) carbonic acid derivatives, xv) Benzoic acid, xvi) benzoic acid derivatives, and xvii) mixtures of i)-xvi), and from 0.01% to 4% based on the weight of the polyolefin of at least one surfactant having a molecular weight of greater than 175 g/mol, and selected from the group consisting of cationic, anionic, non-ionic, amphoteric, and mixtures thereof; B) wherein the melt extrusion is carried out in the absence of fluorinated or siloxane additives.
  2. 2 . The process as claimed in claim 1 wherein the carbon-based material in the thermoplastic composition has an acid value of from 0.1 to 500 mg/KOH.
  3. 3 . A process as claimed in claim 1 wherein the molecular weight of the carbon-based material is between 140g/mol and 10,000 g/mol.
  4. 4 . A process as claimed in claim 1 wherein the molecular weight of the carbon-based material is between 250 g/mol and 1,000 g/mol.
  5. 5 . A process as claimed in claim 1 wherein the molecular weight of the surfactant in the thermoplastic composition is between 300 and 10,000 g/mol.
  6. 6 . The process as claimed in claim 1 wherein the polyolefin thermoplastic composition further comprises, in addition, process aids selected from the group consisting of: i) polyethylene glycol, ii) polyalkylene glycol, and iii) metal carboxylic salts.
  7. 7 . A thermoplastic composition comprising an extrudate derived from A) a polyolefin selected from the group comprising: a) a linear polyolefin, b) a branched polyolefin, c) a homopolymer of polyolefin, d) a copolymer polyolefin, e) a terpolymer polyolefin, and f) mixtures of a)-e); B) from 0.01% to 4% based on the weight of the polyolefin of a material selected from the group consisting of a linear carbon-based material, and a branched carbon-based material, and mixtures thereof, each having a molecular weight greater than 140 g/mol and each having an acid value between 0.01 and 500 mg/KOH with an acid functionality on a backbone thereof consisting of one or multiple functional acid groups selected from the group consisting of: i) phosphoric acid, ii) phosphoric acid derivatives, iii) sulphonic acid, iv) sulphonic acid derivatives, v) carboxylic acid, vi) carboxylic acid derivatives, vii) dicarboxylic acid, viii) dicarboxylic acid derivatives, ix) tricarboxylic acid, x) tricarboxylic acid derivatives, xi) acrylic acid, xii) acid modified acrylic acid derivatives, xiii) carbonic acid, xiv) carbonic acid derivatives, xv) benzoic acid, xvi) benzoic acid derivatives, and xvii) mixtures of i)-xvi); from 0.01% to 4% based on the weight of the polyolefin of at least one surfactant having a molecular weight of greater than 175 g/mol, and selected from the group consisting of: cationic, anionic, non-ionic, amphoteric, and mixtures thereof.
  8. 8 . A thermoplastic composition as claimed in claim 7 wherein, in addition, the carbon-based material is further modified with an oxide material selected from the group consisting of i) ethylene oxide and ii) propylene oxide.
  9. 9 . A thermoplastic composition as claimed in claim 7 wherein the carbon-based material is further modified by a material selected from i) esters and ii) partial esters.
  10. 10 . A thermoplastic composition as claimed in claim 7 wherein the carbon-based material is further modified by hydrogenation.
  11. 11 . The thermoplastic composition as claimed in claim 7 wherein the carbon-based material is further modified with a compound selected from the group consisting of: i) an amine and ii) an amide.
  12. 12 . The thermoplastic composition as claimed in claim 7 wherein the carbon-based material is further partially modified with reaction to make a metal salt.
  13. 13 . The thermoplastic composition as claimed in claim 7 wherein the carbon-based material is reacted onto the polyolefin backbone.
  14. 14 . The thermoplastic composition as claimed in claim 7 wherein a primary antioxidant is added thereto.
  15. 15 . The thermoplastic composition as claimed in claim 7 wherein a secondary antioxidant is added thereto.
  16. 16 . The thermoplastic composition as claimed in claim 7 wherein UV absorbers are added thereto.
  17. 17 . The thermoplastic composition as claimed in claim 7 wherein light stabilizers are added thereto.
  18. 18 . The thermoplastic composition as claimed in claim 7 wherein at least one metal deactivator is added therein.
  19. 19 . The thermoplastic composition as claimed in claim 7 wherein zinc oxide is added thereto.
  20. 20 . The thermoplastic composition as claimed in claim 7 wherein a slip aid selected from the group consisting of: i) oleamide, ii) Erucamide, iii) Stearamide, and iv) behenamide is added thereto.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable. REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX Not Applicable. BACKGROUND OF THE INVENTION Prior art fluoropolymer-based processing aids in polyolefin resins have been used for many decades. They are used in resins like polyethylene to eliminate melt fracture, lower die pressures, and reduce die lip buildup. For other polyolefins like polypropylene, fluoropolymer process aids are used in much lower volume due to the shear thinning behavior of the resin, and the fact that the polymer chain scission during degradation lowers the polymer melt viscosity, making it less susceptible to melt fracture. Still, fluoropolymer process aids can be effective in polypropylene for lowering extrusion pressure, increasing polymer throughput, and eliminating die drool or die lip build-up. For other olefins, like polybutene and other polymers, with ethylene as a comonomer, the use of fluoropolymer process aids is less mentioned in literature, however, are commonly used in commercial practice. By utilizing a process aid in a polyolefin, it allows for the ease of processing of a polymer through a die during extrusion. This happens in one of two ways. If the process aid functions as an external process aid, it will go to the interface between the polymer and the die and provide lubrication. This lubrication lowers shear stress and allows for easier movement of the polymer through a die. Another possible way process aids can ease the processing of a polymer through a die is as an internal process aid. An internal process aid will act between the polymer chains and allow the polymer chains to move more easily past one another. With internal process aids, they lower the apparent viscosity of the material which allows the material to act like it has a lower viscosity, thus allowing it to move more easily through a die. With regard to polyolefins, the largest use of process aids is in polyethylene, specifically, linear low-density polyethylene (LLDPE) followed by high density polyethylene (HDPE). The reason for this is during the extrusion of LLDPE, surface defects commonly known as melt fractures or sharkskin may occur which is a result when the shear rate at the surface of the polyolefin polymer is sufficiently high that the surface of the polymer begins to fracture. The severity and type of melt fracture appearance is the result of molecular weight distribution of the polyethylene resin, the shear thinning profile of the specific resin, the extrusion process, the die gap, and the speed of processing. Fluoropolymer process aids function very effectively as external process aids, as they will coat a die during extrusion. This coating serves to help reduce melt fracture; however, it also helps to reduce and, in many cases, prevent die lip buildup which is not something that can be done by an internal process aid. Within the structure of fluoropolymers, there are localized acidic functionalities or materials that could degrade to an acid with higher temperature which allows it to coat and almost bond to a die surface due to the interaction of the metal and the acid. It is this interaction that gives the fluoropolymers their excellent performance as process aids. The performance of bonding is accomplished by the acidic nature of the material. However, the die lip protection is further supplemented by nature of the fluoropolymer material to behave like a surfactant, specifically an anionic surfactant. A surfactant is defined as a molecule that lowers the surface or interfacial tension between two materials, in this case, the die and the molten polymer stream. As a general class of materials, fluoropolymers have been used to alleviate melt fracture due to their excellent performance. The reason fluoropolymers perform well is due to their properties starting with the molecular structure, specifically that it orients in a helical structure. This kind of molecular packing allows for a tightly packed structure that is still very open on the atomic level due to carbon fluorine bonds. This kind of packing leads to low friction and excellent physical properties which are exhibited as high durability when they coat a die in extrusion processing. Despite fluoropolymers being a great chemistry for lubrication, over the last several years, many fluoropolymer chemistries have been grouped under the umbrella of Per and polyfluoroalkyl substances (PFAS) which has come into question and now have been widely labeled as “forever chemicals” due to the fact that they are widely present in the environment, accumulate in humans, and do not break down quickly. As a general class of materials, surfactants play an important role in many processes such as cleaning, wetting, dispersing, emulsifying, foaming and anti-foaming. Surfactants are found in many products including paints, emuls