What ink is used to print sterilization instruction labels?
Date: Mar 05 2025 From: Star Color
Sterilization indicator labels are common tools for verifying the effectiveness of sterilization. Their core function is to visually reflect whether the sterilization process is completed through color changes. Additionally, they may carry key information such as product batches, expiration dates, and sterilization parameters. To achieve these functions, the printing inks for sterilization indicator labels not only need to possess conventional printing properties but also meet a series of special requirements such as sterilization response and safety compliance.
Functions and Printing Requirements of Sterilization Indicator Labels
- Core Functions
- Sterilization Verification: The most crucial function of sterilization indicator labels is to indicate the effectiveness of the sterilization process through color changes. For example, common color changes include blue to gray, and orange to yellow. These obvious color transitions enable operators to quickly and intuitively determine whether the sterilization is successful after the sterilization process is completed.
- Information Identification: In addition to indicating the sterilization effect, sterilization indicator labels also shoulder the important mission of carrying key information such as product batches, expiration dates, and sterilization parameters. This information helps operators accurately understand the relevant information of the products, ensuring the safety and effectiveness of the products during use.
- Printing Requirements
- High-precision Color Change: To ensure the accuracy of sterilization indication, the color changes of the labels must be strictly matched with sterilization parameters such as temperature, concentration, and time. Only in this way can the actual situation of the sterilization process be accurately reflected through color changes, avoiding misjudgment.
- Weather Resistance: Sterilization indicator labels need to maintain stable performance in various complex environments. They must not only withstand extreme conditions such as high temperature, high humidity, and strong oxidation in the sterilization environment but also adapt to various environmental changes during transportation and storage, such as a freezing environment at -70°C.
Common Ink Types for Sterilization Indicator Labels
- Classification by Sterilization Method
- Steam Sterilization Indicator Ink: The color change mechanism of steam sterilization indicator ink is that under the action of high-temperature steam (121°C/134°C), acid-base indicators or metal salts react, resulting in color changes. Common color changes include blue to gray and green to colorless.
- Ethylene Oxide (EO) Sterilization Indicator Ink: The color change principle of ethylene oxide sterilization indicator ink is that EO gas undergoes an alkylation reaction with the dye, causing the color of the ink to change, such as from orange to yellow and from purple to white.
- Hydrogen Peroxide Plasma Sterilization Indicator Ink: Hydrogen peroxide plasma sterilization indicator ink realizes color changes by hydrogen peroxide oxidizing reducing dyes such as indigo. It usually shows color changes from red to colorless and from blue to white.
- Classification by Ink Composition
- Water-based Ink: Water-based ink, with the advantage of zero VOC emissions, has become a representative of environmentally friendly inks. It is safe and environmentally friendly and is suitable for printing on absorbent substrates such as paper and dialysis paper. However, water-based ink also has some limitations. For example, its drying speed is relatively slow, and supporting drying equipment is required to improve production efficiency.
- UV Curing Ink: The characteristic of UV curing ink is that it can be instantly cured under the irradiation of a UV lamp. It has the advantage of strong wear resistance and is suitable for printing on non-absorbent substrates such as PET films. However, using UV curing ink requires the installation of UV lamp equipment, which increases production costs.
Core Technical Indicators of Inks for Sterilization Indicator Labels
| Indicator |
Requirement |
| Color Change Sensitivity |
ΔE≥5 (distinguishable by the naked eye), response time ≤ 10 minutes after the end of the sterilization cycle |
| Adhesion |
Pass the ASTM D3359 5B test (substrates include dialysis paper, Tyvek®, PET/PE composite film) |
| Chemical Resistance |
Resist wiping with alcohol and hydrogen peroxide, with no peeling off or blurring after sterilization |
| Migration Safety |
Pass the EN 868-5 migration test, comply with FDA 21 CFR 175.300 (standard for food contact materials) |
| Storage Stability |
The color is stable for ≥ 24 months in the non-sterilized state, and it should be stored sealed at 5-35°C |
Adaptability of Printing Processes
- Flexographic Printing: Flexographic printing is suitable for printing with water-based and UV inks. Its advantage lies in a high printing speed, which can reach 150-300 meters per minute, and it is suitable for printing large areas of solid colors. In terms of the selection of the anilox roller, it is usually 150-300 LPI, which can be adjusted according to the fineness of the pattern. Flexographic printing can meet the needs of large-scale production while ensuring printing quality.
- Gravure Printing: Gravure printing is suitable for printing with solvent-based and UV inks. It has the characteristic of high resolution, which can reach 200 lines per inch, and can present a printing effect with high color saturation. Therefore, gravure printing is often used for printing labels with high printing quality requirements, such as metal foils and high-gloss films.
- Digital Printing: Digital printing is suitable for printing with inks such as electronic inks and UV inkjet inks. Its greatest advantage is that it supports the printing of variable data, such as batch numbers and QR codes, and is very suitable for the needs of small-batch customization. Digital printing can quickly and flexibly produce different sterilization indicator labels according to customers' personalized needs.
Zhongzhixing sterilization indicator ink comprehensively covers a variety of sterilization methods. Whether it is steam sterilization, ethylene oxide sterilization, or hydrogen peroxide plasma sterilization, etc., it can be accurately adapted. In terms of color change sensitivity, Zhongzhixing sterilization indicator ink can quickly and accurately respond to the sterilization process, with obvious color changes, ΔE≥5, and is distinguishable by the naked eye, ensuring that operators can timely and accurately determine the sterilization effect. It complies with the FDA 21 CFR 175.300 standard and has no chemical migration risk, ensuring the safety of the products.
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