Overview:

On behalf of a client, yet2 is seeking technologies such as coatings, surface treatments, and surface structuring of stainless steel that can delay or prevent the adherence of polymerized scale (residue from the polymerization reaction) to the inner wall of stainless steel polymerization vessels. Alternatively, technologies that create a state in which scale peels off at a very early stage would also be of interest.

During the solution polymerization process for elastomer production, very high molecular weight scale adheres to and accumulates on the inner walls of stainless steel polymerization vessels or pipes. This accumulated scale peels off the stainless steel surface and gets mixed into the product. We believe that such undesirable high molecular weight scale is generated due to the localized retention of monomers in the agitated solution in the polymerization vessel.

Currently, our client’s production process needs to be stopped every six months for a cleaning of the polymerization vessel (and piping) with boiling water and high-pressure water.  To improve efficiency, we are seeking surface treatments or coatings that will reduce the required frequency of these production stoppages for cleaning, by preventing buildup of the polymerized scale.

 

Requirements, Constraints, and Performance Objectives

  1. Substrate: The technology is applicable to the existing stainless steel polymerization vessel (and/or piping)
  2. Performance: The frequency of high-pressure cleaning can be reduced to less than once a year (minimal scale buildup over one year of use)
  3. Surface Structuring Constraint: It is possible to change the shape/surface structure by adding to the stainless steel surface, but it is not possible to cut into the stainless steel surface (thus making it thinner), considering the safety of the polymerization vessel; processing such as attaching a surface-processed metal film to an interior wall is in-scope
  4. Reactivity: Solutions must not react with butyl lithium
  5. Chemical Resistance: Resistance to hydrocarbon solvents and alkali is required
  6. High Temperature Durability: Solutions must withstand the maximum process temperature of 120℃ AND extended exposure to boiling water during the cleaning process
  7. High Pressure Durability: Solutions must withstand the 400kPa vessel operating pressure (seeking technology generally applicable to high-pressure gas vessels)
  8. Durability through the washing process: Solutions must withstand the high pressure water washing process, in addition to temperatures up to 120℃
  9. Thermal conductivity effects: Coatings/treatments must only cause minimal decrease in thermal conductivity of the vessel

 

Although not required, preference is given to technologies that have a proven, application-specific, track record of preventing adhesion in polymerization processes for hydrocarbon resins, such as polyethylene, polystyrene and ABS for plastics, and EPM and EPDM for rubber.

Sampling: The client prefers that prospective technology providers supply a sample coating/treatment on a stainless steel (SUS316L) plate for the purpose of evaluating the anti-adherence effect, OR that the sample coating/treatment be applied on a SUS316L plate that the client provides

Additional interests: This client is also interested in agitator technology that eliminates uneven polymerization by agitating the polymerization vessel, and filter technology that efficiently removes scale.  If you have any experience with the application of such technologies for hydrocarbon resin processing, we would be happy to discuss that.

 

Solution areas considered:

By Industry:

  • Food adhesion prevention technology for food processing equipment
  • Technology to prevent the adhesion of oily components to automobiles (body, glass, etc.), kitchen areas, and medical equipment

 

By Technology:

  • Coating technologies (including super-hydrophobic and super-hydrophilic)
    • This client is operating under the impression that the organic fluorine coating tends to peel off the stainless steel surface; they have not considered it, but otherwise, they would like to discuss it.
    • If you have a good track record in both surface adhesion prevention and strong adhesion of the coating to the surface of stainless steel, we would like to know about it
  • Stainless steel surface structuring/profiling (e.g. microfabrication) technology
  • Removal of precipitation contaminants (e.g. filter) technology
  • Ultrasonic vibration technology

 

Field of use and intended applications:

Coating treatment of stainless steel polymerization vessel and inner wall of piping

 

Additional Information:

The molecular weight of the resin produced with this process is between 100,000 and 200,000, and the scale the client is seeking to prevent/remove is between several hundred thousand and over a million molecular weight.