PU filter has specific requirements for ambient temperature and humidity as follows:
Temperature Requirements: core components of PU filter (such as hydraulic system, motor, feeder, etc.) are temperature sensitive. Too high a temperature will lead to a decreased hydraulic oil viscosity, accelerated aging of seals, or even equipment failure; too low a temperature will increase hydraulic oil viscosity, reduce the fluidity of polyurethane adhesive, and affect the quality of dispensing.
Reference: Cleanroom design standards generally require temperature control in the production workshop between 18 and 28°C (e.g., air filter production environment requirements), while in precision machining fields (e.g., semiconductor manufacturing) temperature fluctuations need to be controlled between + -0.14°C and + -2.8 ° C. Although PU filter do not require very high accuracy, maintaining temperature stability is the key to avoid performance fluctuations.
The properties of polyurethane adhesives are guaranteed: The viscosity and curing time of PU adhesives are greatly influenced by temperature. For example, two-component polyurethane adhesives perform best at 24~28°C; too high or too low a temperature can lead to incomplete or excessively rapid curing, affecting the sealing performance of the filter core.
PU Adhesive Performance Assurance: Reference: The technical parameters of filter cartridge adhesives explicitly require that "material temperature should be controlled between 24°C and 28 ° C" and preheated to 40 ° C to 50°C (winter) through hot plates to ensure fluidity.
Humidity Requirements: prevent raw materials moisture: polyurethane filter used in the production of filter paper, hot melt glue and other materials easy to absorb moisture. Excessive humidity can cause the filter paper deformation, reduce hot melt adhesive viscosity, or even cause the filter cartridge structure to loosen or seal failure.
Reference Basis: In water purifier filters, the adsorption capacity of activated carbon decreases by 40%% at 80% humidity, and microorganisms are easy to grow. Precision machining requires 35% ~ 45% relative humidity to avoid electrostatic vacuuming or dry cracking of materials.
Although there is no specific ceiling on humidity in PU filter machines, it is necessary to refer to similar industry experience to keep humidity within a reasonable range (e.g. ≤ 65% RH) to ensure material stability.
Avoid Static Electricity and Contamination: Low humidity (e.g. RH < 30%) tends to generate static electricity, attract dust and other impurities and affect the cleanliness of the filter cartridge. humidity control is a key measure for production environments requiring ISO 7/8 cleanliness,such as air filter assembly plants.
Refer: Cleanroom design standards recommend limiting relative humidity to 45%~65% (general requirements) or 35%~45% (precision machining) to balance static and moisture requirements.
Comprehensive Recommendations:
Temperature range: 18 to 28°C is recommended. In winter, preheat the PU adhesive with a hot plate; in summer, provide ventilation and cooling to prevent equipment from overheating.
Humidity Range: 35% to 65% RH is recommended to prevent filter paper and hot melt from absorbing moisture or generating static electricity.
Environmental cleanliness: When producing high-precision filters (such as air filters), dust contamination should be reduced through laminar airflow organization in accordance with ISO 7/ 8 cleanliness standards.