Repolymerization and Compatibilization of Thermoplastics in Post-Consumer Recycling Processes by Using Titanate Ester Catalysts

Abstract

How do you walk the walk after you’ve talked the talk? You pledged your company to sustainability goals such as increasing plastic recycle content and reducing carbon footprint – but, how do you get there? There’s more to Plastics Technology Innovation than Industry 4.0. There’s just so much you can do with software and hardware. Optimization cannot be achieved without first making more efficient use of the materials in the products you make.

My mission in life is to teach the more efficient use of raw materials and – as an entrepreneur who has been signing payroll checks for half-a-century – and an inventor with thousands of global patents by me and my customers – I will show how it can be done. We will look at how polymers are made – and how they are compounded – and provide solutions that will reduce cleaning and sorting and allow you to mix all the polymers and fillers in a melt compounder and make a better product faster.

The extruder becomes a reactor for coupling and catalysis of all the materials in the recycle fed into the hopper. Here’s how:

• If Ziegler, Natta & Kaminisky used Titanium and Aluminum catalysts to produce Addition Polymers;
• If Titanate catalysts are used to produce Condensation Polymers;
• If heteroatom Titanate coupling agents compatibilize Fillers with Polymers;
• Monte claims: Why not use Titanate and Aluminum as a catalyst and coupling agent for compatibilizing the Fillers and Polymers (both Addition and Condensation) used in the Plastic to be Recycled.

Current plastic recycling and sustainability goals are limited by the intrinsic incompatibility of many polymers and the negative effect of fillers and impurities on end-product properties thus requiring a high degree of expensive sorting, separating and cleaning. Another barrier is the melt processing of polymers causes chain scissoring resulting in recycle and regrind materials having inferior properties compared to virgin. Current compatibilizers offered to recyclers are based on co-polymers or maleic anhydride modified polymers. Co-polymer compatibilizers require extensive sorting to match up the polarities of the recycled materials and maleic anhydride depolymerizes condensation polymers such as PET and Nylon obviating their use in post-consumer recycle. MAH technology claims to be a coupling agent, which is true for rebuilding molecular weight – but, misnomered when applied to coupling filler and organic interfaces.

Ziegler–Natta catalysts have been used in the commercial manufacture of various polyolefins since 1956. Ziegler showed a combination of TiCl4 and Al(C2H5)2Cl gave comparable activities for the production of polyethylene. Natta used crystalline α-TiCl3 in combination with Al(C2H5)3 to produce the first isotactic polypropylene. Kaminsky discovered that titanocene and related complexes emulated some aspects of these Ziegler-Natta catalysts but with low activity. He subsequently found that high activity could be achieved upon activation of these metallocenes with methylaluminoxane (MAO) −[O−Al(CH3)]n). Monte uses either a Monoalkoxy or Neoalkoxy Titanate in combination with Al2SIO5 mixed metal catalyst in Powder & Pellet forms for In Situ Macromolecular Repolymerization and Copolymerization in the melt – i.e. Polymer Compatibilization… AND … The Neoalkoxy Titanate proton coordinates with inorganic fillers and organic particulates to couple/compatibilize the dissimilar interfaces at the nano-atomic level thus reducing the need for expensive sorting of materials in Recycled Plastics.

Also, many compounders are schooled in silane coupling agent art thus limiting filler and organic interface coupling to hydroxyl bearing materials such as silica and fiberglass – thus categorizing fillers such as CaCO3, BaSO4, carbon black and organics such as oils as contaminants. In addition, silane art requires knowledge of hydrolysis mechanisms and techniques usually outside the realm of melt recycling compounders. In summary, Monte claims: “Nano-Titanium Technology applied at the interface of dissimilar materials is the Holy Grail of Plastics Recycling.

About the Speaker

Salvatore J. Monte, President of Kenrich Petrochemicals, Inc.; B.C.E. Manhattan College; M.S.-Polymeric Materials, NYU Tandon School of Engineering; SPE Fellow & Honored Service Member; Licensed P.E.; PIA Recycle Subcommittee-Compatibilizers; Board of Governors, Plastics Pioneers Association-MTS Newsletter Chair; 32-U.S. Patents (last patent Mar. 5, 2020); Lectures Worldwide on Titanate & Zirconate Coupling agents; 450-ACS CAS Abstracts of published “Works by S.J. Monte”; Classified Top Secret for Solid Rocket Fuel and Energetic Composites Patents for the Insensitive Munitions Program; Lifetime member of the National Defense Industrial Association; Lifetime Member of the BOD-SPE TPM&F Division; External Advisory Committee-UCF NanoScience Tech. Ctr.; Past-Chairman of the NYRG-ACS Rubber Div.; Past-President of the SPE P-NJ Section; Testified several times before Congress on Trade and IP Protection; Business Man of the Year 2015-Bayonne Chamber of Commerce; Rotary Paul Harris Fellow