Introduction
Pressure-sensitive label production involves three main processes: pre-press, printing, and post-press finishing. The post-press stage includes multiple operations such as varnishing, laminating, hot stamping, die-cutting, and slitting. Throughout these processes, environmental temperature significantly impacts product quality and performance.
Industry standards specify optimal conditions: the mechanical industry standard JB/T 9111-1999 "Pressure-Sensitive Label Printing Machines" requires a printing environment temperature of 20°C±2°C, while the publishing industry standard CY/T 93-2013 "Printing Technology - Pressure-Sensitive Label Quality and Test Methods" specifies a testing temperature of 23°C±5°C. However, many printing enterprises struggle to maintain these ideal temperatures, leading to various product quality issues.
Problem Analysis
1. Raw Material Challenges
As shown in Figure 1, the adhesives in pressure-sensitive label adhesive layers are primarily organic polymers with high temperature dependence. Their mechanical properties and viscoelasticity are significantly affected by environmental temperature changes. Typically, material suppliers select adhesives with different initial tack and holding power based on application temperatures and storage environments to meet diverse customer requirements.
2. Printing Difficulties
Environmental temperature substantially affects printing quality, particularly in winter when heating systems may be inadequate. Low temperatures reduce equipment, ink, and substrate temperatures. In offset printing, which relies on ink-water balance for transfer, low equipment temperatures impair transfer efficiency. Cold ink exhibits increased viscosity and reduced flowability, preventing proper distribution between rollers and causing uneven ink transfer. This results in inconsistent color density and compromised image quality on substrates.
3. Die-Cutting Issues
Beyond die-cutting plate and pressure considerations, environmental temperature affects die-cutting precision. Proper die-cutting cleanly severs both face material and adhesive layer (Figure 4). Improper cuts include shallow cuts (Figure 5) causing label waste carry-off, and deep cuts (Figure 6) resulting in backing paper breakage or label removal. Low temperatures reduce adhesive flowability, preventing complete adhesive layer severance during die-cutting and causing label waste removal failures that reduce production speed and compromise quality.
Solutions
1. Raw Material Management
First, thoroughly understand the application substrate. Consider substrate material (paper, plastic, metal, glass), surface characteristics (flat or curved), and environmental conditions (temperature extremes, sunlight exposure, moisture). These factors influence both face material selection and adhesive compatibility. For applications involving cold filling and labeling of food, beverages, or pharmaceuticals, standard adhesives may harden and lose tack at low temperatures. To prevent label detachment, use materials with appropriate low-temperature adhesives featuring higher initial tack.
Second, transport and store pressure-sensitive materials in the production area 24 hours before printing. This allows materials to acclimate to the production environment's temperature (18°C-25°C) and humidity (50%-65%), ensuring equilibrium conditions.
2. Printing Process Adjustments
Ink transfer efficiency directly determines print quality. Methods to mitigate low-temperature ink issues include:
A. Ink Temperature Management
- Place ink containers near heating sources for gradual warming
- For urgent needs, use hot water baths (place sealed ink containers in hot water, avoiding steam exposure, then mix thoroughly)
- Some northern enterprises use insulated boxes to maintain ink temperature until press use
B. Ink Modification
- Add 5%-10% thinning varnish or tack reducer to improve flowability
- Avoid excessive additives causing print mottling or drying issues
- For multi-color work, adjust viscosity sequence (e.g., higher viscosity magenta followed by lower viscosity yellow)
C. Environmental Control
- Increase workshop temperature to meet printing requirements
- Allow equipment to warm up through idle operation before ink application
3. Die-Cutting Optimization
Precise cutting through face material and adhesive layers is crucial. Common pressure-sensitive adhesives include acrylic water-based emulsions and hot-melt adhesives. Acrylic emulsions with lower cohesion cut easily without special tool or environmental requirements. Hot-melt adhesives with higher molecular cohesion demand precise tools and controlled environments, particularly as low temperatures reduce their activity, increasing "flying label" incidents during waste removal.
Improvement methods include:
- Place warm air blowers near die-cutting and waste removal stations
- Install heating plates or rollers on die-cutting equipment
- Store semi-finished products in warm environments before die-cutting
- Utilize residual heat from previous processes (e.g., immediately die-cut laminated products while still warm from lamination heat)
Conclusion
During cold winter months, low production temperatures create multiple challenges in pressure-sensitive label manufacturing. This analysis has examined temperature impacts across three critical areas—raw materials, printing, and die-cutting—and presented corresponding solutions. Implementing these adjustments helps printing enterprises maintain production quality and efficiency throughout winter conditions.
Post time: May-11-2026