What Is the Optimal Printing Solution for Flexible Medical Packaging?

Flexible Packaging in the Medical Device Industry

Flexible packaging is widely used in the medical device sector due to its numerous advantages. By design, it accommodates a variety of shapes and sizes, from surgical instruments to diagnostic kits, while maintaining a crucial balance between durability and ease of use. This ensures that medical products remain sterile and safe while being quick and easy to access when needed.

For medical device manufacturers, meeting the strict regulatory requirements of the healthcare industry is essential. Choosing the right coding and marking solution for printing on flexible medical packaging is a key consideration. In this blog, we will explore the different types of flexible packaging and outline the available coding and marking options to help you make an informed decision.

Types of Flexible Medical Packaging

Flexible medical packaging must act as a barrier against contaminants and withstand various sterilisation processes. Common materials include plastic films such as polyethylene (PE) and polypropylene (PP), foil laminates, and coated paper-based materials.

Tyvek®, a flash-spun high-density polyethylene fibre material from DuPont, is one of the most widely used brands in medical device packaging. Known for its durability, breathability, and strong microbial barrier properties, it plays a crucial role in ensuring product integrity within the healthcare industry.

Coding Requirements for Medical Devices

Accurate, clear, and durable product codes are essential for medical device packaging, serving several critical functions:

1. Compliance with Regulatory Standards

Regulations such as the EU Medical Device Regulation (EU MDR) require specific product information to be printed on packaging. This includes serial numbers, unique device identifiers (UDI), batch numbers, and expiration dates to ensure traceability and patient safety.

2. Traceability and Inventory Management

Medical device manufacturers and supply chain partners rely on scannable 2D codes to efficiently track and trace medical products throughout the supply chain. These codes facilitate inventory management and help prevent supply chain disruptions.

3. Product Identification and Authenticity

For high-risk medical devices, serial numbers and 2D barcodes are required to verify product authenticity. This helps protect patients from counterfeit products and ensures that only certified medical devices reach healthcare providers.

4. Patient Communication and Safety

Product packaging may include usage instructions, safety warnings, and regulatory information to ensure medical devices are used correctly. Clear, legible printing on flexible packaging is crucial to safeguarding both patients and healthcare professionals.

Printing Technologies for Flexible Medical Packaging

There are three main printing technologies commonly used for coding and marking on flexible medical device packaging:

1. Thermal Transfer Overprint (TTO)

• Provides high-resolution, durable prints
• Ideal for variable data printing such as batch codes, expiry dates, and barcodes
• Best suited for flat, flexible packaging materials

2. Thermal Inkjet (TIJ)

• Delivers precise, high-quality codes at high speeds
• Works well for porous and non-porous surfaces
• Requires minimal maintenance and offers clean, solvent-free printing

3. Piezo Drop-on-Demand (DOD) Inkjet

• Suitable for high-speed applications
• Can print on a variety of surfaces, including curved and textured packaging
• Works well for large character printing and high-contrast markings

Factors to Consider When Choosing a Printing Technology

1. Production Speed – Each printing technology has specific speed limitations that affect code clarity.
2. Printing Distance – Ensuring the correct printhead distance is essential for achieving high-quality codes.
3. Production Line Stability & Vibration – Vibration can affect print clarity, particularly in high-speed environments.
4. Packaging Material – Certain inks and printing methods work better on specific materials; some may require pre-treatment to ensure adhesion and durability.

Identifying the Ideal Solution

To achieve optimal code quality and compliance, a detailed assessment of production line conditions, material compatibility, and ink adhesion is essential.

Domino’s Sample Testing and Analysis for Medical Paper Printing

As part of Domino’s global commitment to ensuring optimal performance and compliance, our experts regularly conduct experimental printing and analysis of product packaging. This rigorous process helps to identify potential solutions to improve the legibility, durability, and compliance of packaging, especially in the medical industry. Below are the specific testing methodologies used in evaluating medical paper printing:

Visual Inspection

• Purpose: To assess the legibility and clarity of the print.
• Method: We measure optical density, which quantifies the darkness and clarity of the print. This is particularly important for ensuring that essential information, such as dosage instructions and expiry dates, is clearly visible and compliant with industry standards.

Rub Resistance

• Purpose: To simulate abrasion that printed pharmaceutical packaging might experience during transportation and handling.
• Method: The printed material undergoes 1,600 cycles of rubbing with a crocking cloth. This replicates the friction experienced by packages in real-world conditions and ensures the print remains intact and legible.

Scratch Resistance

• Purpose: To assess the durability of the print against scratches that could occur during handling and transportation.
• Method: The printed surface is subjected to 50 cycles using a 12-micron 3M lapping film on a crockmeter. This ensures that the printed information remains intact despite scratches.

Steam Sterilization

• Purpose: To evaluate the impact of steam sterilization on the print’s durability.
• Method: The print is exposed to autoclave sterilization conditions (121°C, high pressure, and high humidity for 60 minutes). This tests whether the print can withstand harsh sterilization processes without degrading or losing legibility, ensuring the information stays readable throughout the product’s lifecycle.

Scan Testing

• Purpose: To evaluate the accuracy of barcode and 2D code scanning for product tracking and verification.
• Method: We assess the readability of barcodes and 2D codes using standard barcode scanners, ensuring that they can be scanned and interpreted accurately. This enhances traceability, security, and efficient inventory management within the pharmaceutical supply chain.

These comprehensive tests ensure that the printed information on medical packaging meets the highest standards of legibility, durability, and compliance.

Piezo Inkjet

Thermal Inkjet

Thermal Transfer Overprint

Results of Domino’s Testing on DuPont Tyvek® and Ink Performance for Flexible Medical Packaging

Testing Results on 1073B DuPont Tyvek®:

• Domino BK118 and BK129 inks: Both inks performed well overall, achieving Rub grade B and Steam grade C, with particularly strong results in steam sterilization.

Testing Results on 1059B DuPont Tyvek®:

• Domino BK118 ink: Achieved Very good results in Visual Inspection and Rub Resistance. It received an A grade in Control Grade and Rub Grade, and a C grade in Steam Grade.
• Domino BK129 ink: Also performed well with Very good visual control and Rub grade. However, the Steam Grade was suboptimal.

Ink Technology Performance

1. Piezo Drop-on-Demand (PIJ) Technology:

   • Both water-based and UV-cured inks consistently produced excellent results across all tests, earning an A grade in all categories.
   • Optical density ranged from 0.74 to 0.89.
   • PIJ technology offers a strong balance of high-speed printing with good print density at a higher capital cost.

2. Thermal Inkjet (TIJ) Technology:

   • BK129 ink delivered the best results overall, especially on the 1059B Tyvek® surface.
   • BK652 ink showed good visual results, but further tests revealed irregular performance.
   • TIJ technology provides a good all-around result but with a smaller print footprint compared to others.

3. Thermal Transfer Overprint (TTO) Technology:

   • TTO inks generally performed well, with an optical density range between 1.21 and 0.88 after rub and autoclave tests.
   • While TTO technology offers the highest optical density, it operates at a slower printing speed compared to the other two technologies.

Conclusion

The testing results reinforce that there is no “one-size-fits-all” solution for flexible medical packaging. Various factors, including material handling, production environments, and specific customer needs, all influence the ideal solution for printing on medical device packaging. Through detailed analysis and collaboration with customers, it is possible to develop bespoke solutions that meet the stringent requirements of the flexible medical packaging industry.

Want to Learn More? Contact our Expert Team!