GBPI GBK-1 – Film Thermal Shrinkage Tester (Liquid Bath Method)
- Precision film thermal shrinkage tester for heat-shrinkable packaging films, barrier shrink bags, and sleeve labels
- Full testing compliance with ASTM D2732, GB/T 13519, ISO 14616, and DIN 53369
- Advanced liquid medium immersion bath providing exceptional thermal stability and uniform temperature distribution
- Microprocessor-controlled digital PID thermal regulation from Room Temperature ~ 250 °C with accuracy of ±0.5 °C
- Standard sample grid clamping frame accommodating film specimens up to 140 mm × 140 mm
- High-precision digital timing system with automatic specimen immersion and lifting mechanism
- Robust stainless steel heating reservoir and corrosion-resistant fluid circulation architecture
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The GBPI GBK-1 is a high-precision laboratory film thermal shrinkage tester engineered to determine the unrestrained linear thermal shrinkage rate, shrinkage ratio, and dimensional stability of plastic films and shrinkable packaging materials in a liquid heating medium. Designed in strict compliance with international test standards including ASTM D2732 (standard test method for unrestrained linear thermal shrinkage of plastic film and sheeting) and GB/T 13519, this instrument provides packaging manufacturers, film converters, and quality assurance laboratories with quantitative data to optimize shrink sleeve performance and packaging tight-fit integrity.
Heat-shrinkable polymer materials — including polyethylene (PE), polyvinyl chloride (PVC), oriented polystyrene (OPS), polyethylene terephthalate glycol (PETG), and cross-linked polyolefin (POF) — rely on precisely controlled thermal shrinkage characteristics to secure food items, bundle beverages, and form tamper-evident container closures. If the shrinkage rate is inadequate, the final package exhibits loose wrinkling and poor aesthetic appeal; conversely, excessive shrinkage tension risks crushing delicate primary containers or distorting high-resolution printed graphics. Operating as an industry-standard film thermal shrinkage tester, the GBPI GBK-1 subjects pre-conditioned specimens to a precisely regulated thermal bath, allowing laboratory technicians to quantify shrinkage percentages across both machine direction (MD) and transverse direction (TD).
Uniform Liquid Medium Heating & PID Precision
Unlike forced-air heating chambers that may suffer from turbulent thermal drafts and uneven edge heating, the GBK-1 employs a high-grade liquid thermal transfer bath (such as silicone oil or glycerol). A smart digital PID controller paired with a platinum RTD sensor regulates the fluid temperature from ambient up to 250 °C with remarkable stability, ensuring uniform thermal conduction across every square millimeter of the submerged specimen.
Calibrated Specimen Cage & Automated Handling
The tester features a standard stainless steel wire mesh specimen basket designed to hold films up to 140 mm by 140 mm freely between screens without mechanical constraint. An automated lifting assembly smoothly immerses the sample into the bath upon timer initiation and retracts it precisely upon completion, eliminating operator timing errors and preventing accidental fluid splashing.
By delivering reliable dimensional shrinkage measurements across diverse polymer formulations, the GBK-1 assists flexible packaging engineers in establishing optimal production heating tunnels and validating raw film supplier consistency.
GBPI GBK-1 Film Thermal Shrinkage Tester – Technical Specifications
| Technical Parameter | Specification Details |
|---|---|
| Test Principle | Unrestrained Linear Thermal Shrinkage in Liquid Heating Medium |
| Applicable Standards | ASTM D2732, GB/T 13519, ISO 14616, DIN 53369 |
| Temperature Control Range | Room Temperature ~ 250 °C |
| Temperature Accuracy | ±0.5 °C (Digital PID regulation) |
| Specimen Size | ≤ 140 mm × 140 mm (Standard 100 mm × 100 mm gauge marks) |
| Timer Setting Range | 0.1 s ~ 999.9 s (High-precision digital countdown timer) |
| Heating Medium | Silicone thermal oil, glycerol, or suitable heat-transfer fluid |
| Specimen Clamping Frame | Dual-layer stainless steel mesh cage for unrestrained expansion and shrinkage |
| Fluid Circulation | Internal thermal convection maintaining uniform fluid temperature field |
| Overall Dimensions | 320 mm (L) × 400 mm (W) × 260 mm (H) |
| Power Supply & Consumption | AC 220 V ±10%, 50 Hz / 60 Hz; Total Power: 1500 W |
| Instrument Net Weight | Approximately 24 kg |
Key Features & Engineering Highlights
- Compliance with ASTM D2732: Engineered specifically for evaluating the unrestrained linear thermal shrinkage of plastic film and sheeting in liquid media.
- Precision Digital PID Thermal Control: Provides rapid thermal stabilization from ambient up to 250 °C with tight temperature control accuracy within ±0.5 °C.
- Unrestrained Dual-Mesh Wire Basket: Holds specimens securely while allowing unrestrained thermal shrinkage in both MD and TD orientations.
- Integrated Automatic Immersion Assembly: Features a synchronized immersion and retrieval mechanism to ensure exact specimen exposure dwell times.
- Heavy-Gauge Stainless Steel Bath: Resists chemical degradation, high-temperature thermal fluids, and mechanical wear over years of daily testing.
- Dual-Line Digital Display: Real-time display showing target temperature, process temperature, and countdown dwell timer simultaneously.
- Operator Safety System: Over-temperature safety limit cutoff and insulated outer chassis protect operators during high-temperature thermal cycles.
Standard Package & Accessories
| Item Description | Quantity |
|---|---|
| GBPI GBK-1 Film Thermal Shrinkage Tester Mainframe | 1 Unit |
| Stainless Steel Wire Mesh Specimen Clamping Frames | 3 Sets |
| Precision Specimen Marking & Measuring Template (100 mm × 100 mm) | 1 Pc |
| High-Temperature Handling Tongs & Specimen Retrieval Tools | 1 Set |
| Power Supply Cable & Grounding Wire | 1 Set |
| Operating Manual & Factory Calibration Certificate | 1 Set |
Target Industry Applications
Beverage & Container Shrink Sleeves
Testing PETG, PVC, and OPS full-body shrink sleeve labels for bottles, cans, and contoured cosmetic jars to ensure distortion-free graphic shrinking.
Food & Meat Barrier Shrink Bags
Evaluating multi-layer coextruded barrier shrink bags (PVDC/PE, EVOH) for vacuum packaging of fresh meats, poultry, and block cheeses.
POF Overwrap & Bundling Films
Optimizing shrink rates of cross-linked polyolefin (POF) and polyethylene collation shrink films used in multipacks and pharmaceutical box wrapping.
Battery Separators & Electronics
Assessing high-temperature dimensional thermal shrinkage of microporous lithium-ion battery separator films to prevent internal short circuits.