Frequently Asked Questions

INHANCE® Particles

1. Can I selectively add particles to a specific surface of a molded item?

2. Are changes required in the molding processes for polyurethane parts that incorporate INHANCE® particles?

3. Will a part molded with INHANCE® particles have a low coefficient of friction surface as it comes out of the mold?

4. INHANCE® particles have functional groups that can be reactive in some systems such as 2-part polyurethane. Does the stoichiometry need to be adjusted to compensate for these groups?

5. Can I add INHANCE® polyethylene particles to latex paints?

6. Can INHANCE® particles be used in clear coatings?

7. Can INHANCE® particles be processed with standard meter-mix polyurethane casting equipment?

8. Are INHANCE® particles available in colors?

9. Does use of INHANCE ® polyethylene particles in a coating decrease adhesion to substrates?

10. Does use of INHANCE ®particles in a formulation result in higher costs?

11. What is the best loading level to use?

12. Since INHANCE® polyethylene particles provide surfaces with lower coefficients of friction, how can these products be used in slip-resistant coatings?

13. Can colored coatings be formulated with INHANCE® particles?

14. How is it possible that INHANCE® polyethylene particles and fibers increase the strength of a material, such as polyurethane, even if the tensile strength of HDPE is lower than that of the polyurethane?

15. Do INHANCE® particles and fibers have a shelf life?

INHANCE® TiC – Particles

1. What exactly are INHANCE® TiC Polymer Alloys?

2. Are special processing conditions required for molding products with these additives?

3. How are these products combined with thermoplastics?

4. Why titanium carbide?

5. Do these additives cause excessive wear on counter surfaces?

6. What problems or opportunities are INHANCE® TiC polymer alloys designed to solve?

6. What problems or opportunities are INHANCE® TiC polymer alloys designed to solve?

7. What are some examples of end products for which INHANCE® TiC polymer alloys are well suited?

1. Can I selectively add particles to a specific surface of a molded item?
A. Yes. INHANCE® particles improve abrasion and wear characteristics in a variety of applications, including molded items. Because INHANCE® polyethylene particles are less dense than most liquid matrix precursors, they will float upwards until gelatin occurs. In applications that need low viscosity and long pot life, such as floor coatings, the polyethylene particles will concentrate at the top, where abrasion resistance is most needed.

In molded applications where higher viscosity and shorter pot life are desirable-spin-casting a wheel or gear, for example-a two-step process will ensure even distribution of INHANCE® particles throughout the molded item. First, add matrix polymer filled with INHANCE® polyethylene particles, then incorporate unfilled matrix.

INHANCE® titanium products are denser than most matrix liquids. Working with our titanium product requires the opposite approach from working with its polyethylene counterpart. For thermoplastic processes, selective placement of the particles requires more sophisticated techniques such as sequential mold filling or co-extrusion.

2. Are changes required in the molding processes for polyurethane parts that incorporate INHANCE® particles?
A. No major changes are required. INHANCE® particles increase the viscosity of a system. This will require more energy for mixing and increased viscosity may make it more difficult to de-aerate the mix. This is typically compensated for by mixing and de-aerating for longer periods and, sometimes, by increasing the temperature.

3. Will a part molded with INHANCE® particles have a low coefficient of friction surface as it comes out of the mold?
A. No. During mixing and molding, the particles become coated with a very thin layer of matrix material. Thus, the surface of molded items consists of matrix polymer, which is frequently further coated with residual mold-release agents. To experience the low coefficient of friction provided by INHANCE® particles, you must abrade away a portion of the surface to expose the particles.

4. INHANCE® particles have functional groups that can be reactive in some systems such as 2-part polyurethane. Does the stoichiometry need to be adjusted to compensate for these groups?
A. Adjustments in stoichiometry are not required. While there is a large number of functional groups on the surface, the treated layer is very thin-a few molecular layers in depth. Thus, their absolute number is miniscule in comparison to the entire system.

5. Can I add INHANCE® polyethylene particles to latex paints?

A. Yes. Because of the high surface energy of the particles, they readily wet and disperse in latex using usual mixing technology. However, since the particles are slightly acidic, take care not to destabilize (and coalesce) lattices that are sensitive to pH reduction. In those cases, add an appropriate pH buffer to the formulation.

6. Can INHANCE® particles be used in clear coatings?

A. Yes. INHANCE® polyethylene particles will reduce the clarity of clear coatings somewhat, depending on the particle size product used and the loading level used. INHANCE® titanium products always make coatings dark and opaque.

7. Can INHANCE® particles be processed with standard meter-mix polyurethane casting equipment?

A. Surface-modified particles can be processed with several types of meter-mix equipment with little or no modification. The biggest problem encountered is the clogging of screens and metering valves. Equipment such as Flying Wedge and Liquid Controls can be used with no modifications. APS machines sometimes require different pumps, such as Zenith. Edge Sweets Inc. has developed a special mixhead for use of particles with their machines. Equipment with meter valves, such as Max, may or may not require ancillary particle handling equipment, depending on the particle size of the INHANCE® materials being used.

8. Are INHANCE® particles available in colors?

A. These products are not available in colors at this time.

9. Does use of INHANCE® polyethylene particles in a coating decrease adhesion to substrates?

A No. In fact, in many cases the use of INHANCE® polyethylene particles will result in stronger substrate adhesion than you would obtain even using non-filled coating with a primer.

10. Does use of INHANCE® particles in a formulation result in higher costs?
A. Adding INHANCE® particles modestly increases material costs but generally reduces life cycle costs. This material cost increase must be contrasted with the higher performance properties of the end products, including greater durability. Life cycle analyses of labor and downtime associated with earlier part failure generally show that increased durability has positive cost implications that more than offset the modest increase in the cost of the parts.

11. What is the best loading level to use?

A. From a performance perspective, the optimal loading level depends on the property being optimized and the system to which the particles are being added. Furthermore, many other physical properties will change in various ways. Examples of other properties that change include % elongation, ultimate tensile strength, and density. Therefore, testing for each system and application is required and a cost/benefit relationship should be examined. A good starting point for INHANCE® particle incorporation is 15% to 30% by weight for the total system.

12. Since INHANCE® polyethylene particles provide surfaces with lower coefficients of friction, how can these products be used in slip-resistant coatings?

A. If the INHANCE® polyethylene particles used in a coating are approximately 50% larger in diameter than is the thickness of the coating being applied, the particles will create a profile that is very effective in imparting slip resistance for shoe soles.

13. Can colored coatings be formulated with INHANCE® particles?
A. Yes, with use of appropriate opacifiers, such as TiO2, colorful paints and coatings can be made. Of course, inclusion of the INHANCE® particles (black or white) will somewhat effect the final color.

14. How is it possible that INHANCE® polyethylene particles and fibers increase the strength of a material, such as polyurethane, even if the tensile strength of HDPE is lower than that of the polyurethane?
A. The strength of a material is determined by the type of stresses imposed on a specimen and the failure mechanisms involved. A very important failure mechanism for elastomeric polyurethane is tearing. Incorporation of surface-modified particles and fibers, which bond tenaciously to polyurethane, are generally very effective in increasing tear resistance, which in turn increases overall strength.

2. Are special processing conditions required for molding products with these additives?
A. No, TiC-filled polymers use the same process conditions used to mold the unfilled polymers.

3. How are these products combined with thermoplastics?

A. Since INHANCE® TiC polymer alloy products are very fine powders, they need to be compounded with plastic resins to generate pellets suitable for use in injection molding or extrusion. (Compounding is the melt-mixing process by which additives are mixed into thermoplastics using a specially designed extruder.) Some customers have mounted volumetric feeders on their molding equipment to enable direct blending in the barrel of injection molding and extrusion machines.

4. Why titanium carbide?
A. Titanium carbide is the 3rd-hardest known material, almost as hard as diamond. It is extremely abrasion resistant and chemically inert.

5. Do these additives cause excessive wear on counter surfaces?
A. While titanium carbide grains are abrasion resistant, they do not cause excessive wear on counter surfaces. This is because titanium carbide grains are rounded, like river rocks. Metal carbides other than titanium carbide are sharp and angular, making them excellent for cutting and grinding.

6. What problems or opportunities are INHANCE® TiC polymer alloys designed to solve?

A. There is a growing need for high-performance plastics that have high abrasion resistance and high temperature stability. These are being used in place of metal for the manufacture of gears, bearings, seals, impellers, pistons, rings, and protective jacketing.

Today over 50% of newly designed mechanical moving parts are being made in high-performance, engineering polymers. High-performance polymers are used instead of metal because they give better end-product performance, increased corrosion resistance, higher impact resistance, increased part durability, no need for lubrication, and reduced part weight.

7. What are some examples of end products for which INHANCE® TiC polymer alloys are well suited?
A. Examples of ideal product applications include: rotating bearings and components for equipment such as downhole tooling, pumps, engines, mechanical gears and transmission parts.