How to Properly Store Flexographic UV Ink

Date: May 20 2025 From: Star Color Views:

I. Core Storage Parameter Matrix

The storage environment of UV inks directly impacts their chemical stability and printing performance. Below are key indicators with safety thresholds, over-limit risks, and monitoring tools:

Indicator	Safety Threshold	Over-limit Risk	Monitoring Tool
Temperature	15–25°C	>28°C → Accelerated prepolymerization reaction, causing ink to thicken or cure prematurely	Electronic temperature recorder (±0.5°C accuracy)
Relative Humidity	40–60%RH	>70%RH → Moisture absorption leads to viscosity anomalies and affects printability	Temperature-humidity sensor (cloud-synced data)
UV Intensity	<5μW/cm²	>20μW/cm² → Premature activation of photoinitiators, causing surface skinning and waste	UV illuminometer (e.g., Testo 540)
Stacking Pressure	<200kg/m²	>300kg/m² → Barrel deformation and leakage risks	Pressure-sensitive labels (visual alarm)

Industry Standard: Comply with ISO 2846-1:2023 General Requirements for Storage of Printing Inks to ensure storage environments meet international specifications.

Starcolor Flexo UV ink

II. Light Protection and Anti-Polymerization Operation Specifications

1. Photosensitive Protection Solutions

Packaging Design:

Use double-layer containers: inner layer of black HDPE (high-density polyethylene) to block visible light; outer layer of aluminum foil for light shielding, with UV blocking rate >99% (tested at 395nm wavelength).
Sealing lids must pass UV blocking performance tests to ensure complete isolation of UV light during storage.

Warehouse Modification:

Lighting system uses red light sources (wavelength >620nm, intensity <10lux) to avoid blue/UV light triggering premature ink reactions.
Windows installed with UV blocking film, blocking >95% of wavelengths below 380nm to shield natural UV light.

2. Open-Lid Operation Rules

Single material retrieval time controlled within 3 minutes to minimize ink-light exposure.
After temporary opening, immediately cover with aluminum foil shading cloth (reflectivity >85%) to block residual light.

III. Precise Temperature and Humidity Control

1. Seasonal Management Strategies

Environmental challenges and solutions for different seasons:

Season	Challenge	Solution	Equipment Configuration
Summer	High temperature (>30°C)	Constant-temperature cold storage with ±2°C fluctuation control	Dual-compressor industrial chillers for efficient cooling
Winter	Low temperature (<10°C)	Ink preheating room maintained at 25°C	Infrared heating panels + intelligent temperature controllers for uniform heating
Mei Rain Season	High humidity (>75%RH)	Rotary dehumidifiers with dew point controlled at -40°C	Humidity closed-loop control system for real-time adjustment

2. Ink Rewarming Operations

Refrigerated inks must follow a stepwise rewarming protocol: 5°C → 15°C → 25°C, with each stage lasting ≥4 hours to avoid component separation due to excessive temperature differences.
Direct heating (e.g., open flames, heat guns) is strictly prohibited; temperature differences >10°C may cause ink delamination and affect print quality.

IV. Container Sealing and Stacking Standards

1. Sealing Grade Classification

Select appropriate sealing methods based on storage duration and ink characteristics:

Sealing Method	Oxygen Permeability (cc/m²·day)	Application Scenario
Standard Screw Cap	50–80	Short-term storage (<30 days), suitable for regular production batches
Nitrogen-Filled + Silicone Seal	<5	Long-term storage (>6 months), ideal for inventory backup inks
Vacuum Aluminum Pouch	0.1–0.5	Sensitive formulations (e.g., inks with TPO photoinitiators) requiring highest-level protection

2. Three-Dimensional Warehousing Specifications

Pallet stacking height ≤3 layers, total height <1.8 meters to prevent bottom container compression deformation.
Storage area kept ≥50cm away from walls for air circulation and heat dissipation; passage width ≥1.2 meters to meet fire safety and handling requirements.
Set up leak-proof containment barriers per OSHA standards, with capacity ≥110% of the largest single barrel volume to prevent safety hazards from accidental leaks.

V. Batch Management and First-In-First-Out (FIFO)

1. Information Management Process

Inbound Stage:

Use barcode scanning to input production date, batch number, shelf life, etc., and synchronize initial viscosity and curing energy values (refer to QC test reports).
Warehouse location allocation follows shelf life principles: Zone A for remaining shelf life >6 months, Zone B for 3–6 months, Zone C for <3 months, facilitating priority shipment.

Outbound Rules:

System automatically triggers expiration warnings (red alert at 30 days remaining) to ensure FIFO compliance and reduce obsolete inventory losses.

2. Shelf Life Extension Techniques

Add 0.1–0.3% polymerization inhibitors (e.g., p-hydroxyanisole) to suppress spontaneous photoinitiator reactions.
Use nitrogen-filled storage (oxygen concentration <200ppm). BASF test data shows this method extends UV ink shelf life by 40%, effectively reducing inventory costs.

By implementing these full-process specifications, enterprises can systematically enhance flexographic UV ink storage management, reduce ink failure caused by environmental factors from the source, achieve a 30% inventory loss reduction goal, and ensure printing production stability and product quality.