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1. Identify your substrate: we often recommend pretreating your device with our 5-017 primer. Depending on the surface energy of your medical device, we may also recommend a corona, flame or plasma pretreatment before priming. Many silane primers, used effectively on stainless steel and metals, bond well with our Hydrophilic Coatings. 

2. Identify performance requirements: Your interdisciplinary product development team should produce a project plan describing what features are needed for surface modifications on the device. For many applications that are searching for a second source of coating, there is an existing specification for coating performance describing the test methods and other requirements for the product. In general, these specifications can be described by the categories similar to those that have been shown under our product lines.

3. VISIT OUR WEBSITE! If there is no category on our Products Page listings to accommodate your requirements, please contact us. Additionally, our sister company, Surface Solutions Labs, can assist you in tailoring these coatings to make them harder or softer, more resilient or less flexible.

For our EU customers, please note that we have a non-NMP version of the Hydrophilic which can be used with Crosslinker B Concentrate (see our Instructions for Use Hydrophilic section for B Concentrate dilution instructions). 

Our standard coatings are:

Primer Urethane 5-017 Kit

Mid-range Hydrophilic Coating Kit 8-3C

Additive compatible (radiopaques, bioactives, pigments, tracers, etc.) Hydrophilic Coating Kit 8-63

Antiblock Urethane, a hard silicone-diol based polymer

Ask us about other primers, different slip-range Hydrophilics and non-NMP versions of our Hydrophilic. Heparin, Antimicrobial and Drug Delivery coatings are available, but will be handled as non-standard coatings through Surface Solutions Laboratories, Inc.

In most instances we would suggest that you begin your evaluations with small amounts and build experience with the viscosity, handling, pot life, and coating application/cure and performance optimization. These patented coating systems are tougher and more durable with better adhesion, but they should be understood prior to plant introduction.

If you are doing a rough evaluation of coating utility and can flow coat from an eyedropper or dip the device into (or pull it through) the coating, then the smaller amounts should suffice. You can always order more or in larger quantities. Making the most of the coating can be a continuous improvement project. Consider the pot life of the mixed coating and geometries of the devices to be coated when deciding on mix quantities. The hydrophilic coating with the Crosslinker B added has limited shelf life, and quantities should be optimized early in the development cycle. Mixing Crosslinker B Concentrate immediately before use will help prolong the coating pot life. On site dilution of the B Concentrate, and/or reduced amounts of the B may also help pot life. More detailed instructions may be found in the Instructions for Use Page.

If requested, we can discuss larger quantities than what are listed for a better economy of scale

More detailed instructions may be found in the Instructions for Use Page

Proper mixing is key to obtaining a stable solution. Pot life on the coating mixed with Crosslinker A can be up to several days, but be ready to coat your device when mixing your kit. Pot life for coatings mixed with Crosslinker B may be only 6 to 8 hours, depending on the solids of the solution, and ambient conditions (temp, humidity, etc.). Crosslinker B, which is used with our hydrophilic coatings, is hygroscopic. It readily absorbs water from the air, can become high in viscosity and eventually gel. Avoid repeated opening/closing and purge the vial with dry nitrogen or carbon dioxide gas as soon and often as possible. Customers have elected to purchase our Crosslinker B Concentrate, diluting it with a co-solvent such as NMP or Acetone  just before use. This eliminates the concern of water absorption upon opening and then reacting with the B functionality. You may opt to specify your orders for Crosslinker B Concentrate, but the premixed Crosslinker B is included in the coating kit.

Mixed coatings may be applied by almost any coating method. Complex geometries and transfer efficiencies often make dipping the preferred method. Flow, spray (DO NOT spray the hydrophilic), brush, and transfer methods— including knife over roll, gravure, and screen—may be employed. Attention to minimizing foam generation is key for many of these methods. There is no defoamer in these formulations, but foam may be suctioned off the top of a bath of coating as needed.

Foam may be skimmed from the top of sedentary reservoirs. Often the incorporation of a solvent can also help by reducing the surface tension of the coating.  Note that additives such as traditional antifoams will present the same issues re potential extractables that FDA may reject. See below “What if my coating will not wet or stick?” for issues with Biocompatibility that may arise with additives that do not leave the films formed during cure.

The Instructions for Use Page will explain in greater detail.

Each coating will dry and/or cure a bit differently depending on factors including, but not exclusive to: the solids content, mix ratio and added crosslinkers; the application method, final coating thickness and curing equipment (type of oven, etc.).

NOTE: drying is a simple evaporation of water or volatiles from the coating, whereas curing is a chemical reaction occurring between reactive groups on the polymers, substrates and crosslinkers. Heat improves molecular mobility, which improves the reactive groups’ ability to access each other.

Please visit our Instructions for Use Page for coating specific details.

• Our primer and hydrophilic coatings without crosslinker will dry by simple evaporation. This can take as little as 5 minutes at 60° to 80°C for a very thin coating, or over 1 hour for thicker. No curing takes place.

• Coatings with Crosslinker A are also dired by evaporation. However, heat improves molecular mobility which improves curing. We would recommend temperatures of 60° to 80°C, but the coating can tolerate 150°C for short periods of time if you device can handle the increased temperature. Excess Crosslinker A hydrolyzes or reacts with functional groups on the substrate, generating innocuous and biocompatible coatings.

• Coatings also using Crosslinker B are also cured with time and temperature. Active hydrogen groups participate in the curing and can be contributed by the substrate, the polymer, or the coating resin. Heat improves molecular mobility which improves polymer chain access to the substrate and Crosslinker A and B groups. Like the other systems, heat and time will help in both the curing of the functional groups and the subsequent hydrolysis of excess reactive groups, generating innocuous and biocompatible coatings. The hydrolysis completion may take a week or more, with properties building and optimizing over several days.

In all cases, you can accelerate drying by using a forced hot-air oven at temperatures that are suited to your substrate materials. Most of the coatings will take temperatures up to 300°F for short periods. It is recommended that you test the process you plan to use to mix, coat, and dry/cure on your device at several different ambient conditions for temperature and humidity conditions once suitable performance is obtained.

Please contact us for recommendations.