Coatings and inks

Chempilots has formulated a range of custom solvent-, UV- and water-based inks, coatings, and adhesives for medical device applications and has experience with a variety of coating and printing techniques.

Formulation
Polymer solubility and Hansen Solubility Parameters (HSP)
Our primary tool in formulation is Hansen Solubility Parameters (HSP), where we use proprietary software tools to find combinations of polymeric binders, pigments and solvents that form homogenously soluble or dispersible systems. From this, an initial shortlist can be further refined to fit a desired surface tension and evaporation profile in combination with minimized environmental exposures.

Use of HSP and our other solvent databases (1000+ solvents) turns formulation into a structured working process instead of a cumbersome trial and error exercise.

Above: HSP plot example

Polymer coating properties
For medical device applications, the important dried-film properties are typically adhesion, cohesion, flexibility, abrasion resistance, wettability, film defects (pin holes, blisters, wrinkling, etc.), biocompatibility, leachables, stability and permeability (water, oxygen, APIs) in combination with any desired additional custom functionality. Chempilots has experience in formulating for these properties and the methods used for characterization.

Processing properties
Formulating for processing usually involves obtaining a stable, homogeneous mixture in combination with a rheology fitted to the method of application - printing, dipping, spraying, etc., as well as proper spreading, leveling, and drying kinetics.

APIs, pigments, fillers, additives
Chempilots has all dispersing, mixing, and milling equipment for development and pilot production of inks and highly filled polymer composites. We also have experience with filler treatment and selection of suitable additives.

UV inks, coatings, and adhesives
UV inks and coatings pose special requirements as formulations are closely tied to the desired product application and processing. Chempilots has a wide range of UV lamps from glass fiber spot curing to fusion lamps for development of UV formulation and processing solutions.

Coating
Choice of coating method
For any product, the choice of coating method depends on a variety of conditions, including geometry of the product and surface to be coated, rheology, thickness, definition, coating speed and level of acceptable defects.

Chempilots can assist you devise robust custom processes where coating formulation, coating method, and drying setup come together in an integrated and cost-effective solution.

Wide range of experience
Our experience lies primarily within dip, spray, spin and slot/extrusion to produce catheter and guide wire coatings, polymeric films, and pressure sensitive adhesives. We also have special experience and equipment for the preparation and coating of highly viscous coatings.

We understand standard roll-coating techniques (blade, gravure, and reverse roll) and have experience with narrow-web handling.

Custom process development
We can assist you with tasks that cannot be accomplished using standard solutions or equipment, or tasks too small or specialized for typical contract manufacturers to consider. Our services include process development, equipment construction, and pilot production.

Printing
Over the years we have worked with pad printing, screen printing, ink jet printing, laser ablation, and photolithographic techniques to lay down custom functional coatings and patterns in the manufacture of medical devices.

Choice of printing process
When putting a functional coating or pattern on a medical device, the choice of printing process depends on a complex balance between many factors.

Over the past two decades, Chempilots has worked with a wide range of specialized printing projects including proprietary markings, contact lens tinting, drug delivery, free form surface formation, wettability enhancement by nano-structuring, and blood-glucose sensor-strip manufacturing. This expertise places us in a unique position to help you achieve your own unique printing objectives. 

Associated printing process issues where can assist
We can also assist in solving associated printing process issues such as: surface priming, cleaning, modification, anti-static treatment, coating evaluation etc.

Drying and curing
Chempilots has a wide range of experience in the design, control, construction, optimization, characterization and validation of drying and curing processes for the medical device industry.

UV curing
UV-light curing is characterized as clean, fast, and having no volatiles. Chempilots has extensive experience with the application of proper UV-light curing systems and the interplay with formulation and coating characteristics. Typical challenges in UV-systems involve tack, adhesion, cohesion, and monomer residuals in products such as acrylic skin adhesives, contact lenses, construction adhesives, and coatings.   

Infrared drying
Infrared drying is a simple, fast, clean, and very controllable way to heat products. Chempilots has constructed several custom single-unit heating and curing systems based on a focused IR emitter source connected in a feedback loop with an IR thermometer sensor. Often, IR heating can be used to great advantage compared to hot air heating. This is especially true when space is limited, very fast heating is required, or heating must be focused to avoid heating the entire product or the surroundings. 

Hot air drying
Optimal air drying or heating processes represent a complex interaction between the formulation characteristics (solvent and binder) and the process characteristics (air temperature, temperature distribution, airflow, and airflow distribution). Typical challenges include: 

• Matching formulation solvent choices with efficient drying processing
• Obtaining a uniform product temperature ramp up
• Balancing drying speed with print/coating defects and substrate warp
• Ensuring full evaporation of solvents

Chempilots has extensive experience with the measurement of air temperatures, airflows, and resultant product temperatures (contact less IR thermometers + IR cameras). 

Analysis methods
Chempilots can provide any of several coating analysis methods relevant to the development and characterization of a drying or curing process. These include:

• Solvent/monomer residuals analysis
• Mechanical properties
• Tack
• Hardness
• Adhesion
• Scratch resistance

Contact us for a discussion
For a confidential discussion of your specific needs, please call Christian Elbek on +45 4495 1661 or send him an e-mail.