In industries like printing, textiles, and composites, bubbling and delamination of polyurethane rollers directly push product rejection rates up by over 30%, causing annual losses exceeding millions of yuan. As an innovator in the polyurethane equipment sector, Feilong Polyurethane Equipment Engineering Co., Ltd., leveraging the R&D strength of its academician workstation, systematically addresses these two major industry issues through cross-disciplinary innovation in materials science, fluid mechanics, and interface engineering.
I. Root Causes: The Scientific Mechanisms of Bubbling and Delamination
Three Causes of Bubbling
- Moisture-sensitive reaction: When environmental moisture penetrates raw materials, water reacts with isocyanate groups to produce CO₂ gas. If not discharged promptly, it forms subcutaneous bubbles. When humidity exceeds 70%, the bubble occurrence rate surges by 300%.
- Temperature field imbalance: Fluctuations of more than ±5℃ in the temperatures of raw materials, molds, and the environment disrupt the dynamic balance between gelation and foaming kinetics, triggering a chain of bubbles.
- Defects in open glue pans: In traditional processes, the adhesive circulation rate is less than 60%. When viscosity rises to 2000cP, bubbles fail to burst and accumulate, overflowing the glue pan.
Four Inducing Factors of Delamination
- Poor metal roller core treatment: If bonding isn't completed within 72 hours after sandblasting, summer moisture causes secondary rusting of the roller core, reducing bonding strength by 40%.
- Thermal stress concentration: A temperature difference exceeding 10℃ between the preheated roller core and polyurethane material leads to microcracks due to curing shrinkage differences.
- Air gaps at the pouring interface: Low-pressure pouring processes (<0.3MPa) can't penetrate micropores on the metal surface, leaving residual air gaps that become the starting point of delamination.
- Primer failure: Ordinary adhesives with a bonding strength of only 12MPa tend to peel at the interface under dynamic shear.
II. Feilong's Core Technical Solutions
Bubbling Control: Triple Active Defense System
- Intelligent temperature control closed-loop: Integrating four-zone independent temperature control modules (raw material tank/pipeline/mixing head/mold), the PID algorithm dynamically compensates for reaction heat release, controlling temperature differences within ±1.5℃. Combined with a vacuum dehydration pretreatment chamber, the raw material moisture content is stably ≤0.03% (industry average 0.05%).
- Two-stage vacuum defoaming: -0.095MPa primary degassing in the premixing stage; -0.1MPa deep vacuum in the mold cavity during pouring, increasing bubble escape rate by 90%. 0.5-2MPa pulse pressure is applied at the gelation critical point to crush residual microbubbles.
- Viscosity-adaptive circulation: The jacketed glue pan system achieves 95% closed circulation. Viscosity sensors link with dilution valves, controlling fluctuations within ±5 seconds (#3 Zahn cup) to prevent bubbles from forming due to solvent evaporation.
Delamination Prevention: Four-Step Interface Enhancement Process
- Intelligent roller core treatment line: Automatically matches sandblasting parameters (80-120 mesh, 0.6-0.8MPa) based on materials (steel/aluminum/copper), keeping roughness Ra stable at 3.2-6.3μm. A nitrogen protection chamber blocks oxidation, with a strict 72-hour bonding time limit (shortened to 24 hours for aluminum roller cores).
- Nano-reinforced bonding technology: Developed NanoBond® polyisocyanate primer, where active nanoparticles penetrate metal surface micropores, forming a rigid-flexible gradient transition layer. Laboratory data shows bonding strength reaches 18MPa, with dynamic shear resistance improved by 40%.
- Gradient temperature-controlled curing: The roller core preheating temperature difference compensation algorithm dynamically adjusts the preheating temperature, ensuring the temperature difference between the material and the roller core is ≤5℃. Ultra-wide equipment uses microwave gradient heating, with the axial temperature difference of 800mm diameter roller cores <3℃.
- Mold-free centrifugal casting: The 2×12m ultra-wide mold-free casting system developed by the academician workstation monitors the adhesive layer thickness in real-time through 3D scanning. It cooperates with a multi-axis centrifugal system (adjustable 200-850rpm) to densify the adhesive layer and eliminate the mold clamping line defects of the molding process.
III. Case Study: From Frequent Failures to Zero-Defect Production
A high-end printing factory once suffered annual losses of 3.6 million yuan due to roller issues:
- Pain points: Polyester rollers (hardness 90A) delaminated at the edges after 2 months of use, and bubble rupture during high-speed printing caused ink bars.
- Feilong's solution:
① JLK jacketed glue pan system stabilizes viscosity (fluctuation ≤±3 seconds)
② Shortens the nano-coating time limit of roller cores to 24 hours
③ 12m mold-free casting line produces integrally formed rollers - Results:
Roller service life extended from 8 months to 28 months
Customer gained new orders worth 17 million yuan
Technically, bubbling and delamination are signs of unbalanced energy transfer. Feilong's innovation lies in establishing a control model for temperature field, stress field, and rheological field, achieving zero interface defects through precise energy management.
Conclusion: Redefining Roller Reliability Standards
Bubbling and delamination are not just process defects but also systemic challenges in the cross-fields of materials science, fluid mechanics, and interface engineering. Through cutting-edge research at its academician workstation (with 3 provincial industrial new product certifications), Feilong Polyurethane Equipment has transformed core technologies such as nano-reinforced bonding, mold-free centrifugal casting, and intelligent three-temperature control into industrial-grade solutions. Installation data over the past three years shows that customers using Feilong's complete set of equipment have seen the roller delamination rate drop below 0.3%, and the bubble defect rate stabilized at 500PPM—marking China's historic leap from following to leading in the field of high-end polyurethane equipment.
