Our company is a famous manufacturer of PU sieve sheet. By virtue of the complete management system, our company establishes a good enterprise image, and wins unanimous praise from all sectors of society. The introduction to the production process of PU sieve sheet as follows.
1. Prepolymer Synthesis
(1) Raw material, oligomeric polyhydric alcohols: ODX2218, CMA21024; poly tetramethylene ether glycol (PTMG 1000), the water content should be lower than 0.05% through dehydration before use. Polyisocyanates: Toluene diisocyanate (TDI2100).
(2) Prepolymer Synthesis: The dehydrated oligomeric polyhydric alcohol is added to the reaction still after cooling down to 40-60°C. The toluene diisocyanate is added while stirring. After reaction for 30-40 min, it is slowly heated to (80 ±) °C for continued reaction in 2-3h. Sampling Analysis: 5NCO%, when reaching 4.0-5.0%, the prepolymer is obtained through vacuum defoamation at a pressure of 0.8kPa.
2. Pouring Technology
(1) Pretreatment of Metallic Framework: To ensure certain stiffness in the using process of PU sieve sheet, generally the sieve sheet is lined with steel framework. Most of steel framework of small and medium-sized sieve sheet is welded frame, while the tensioning screen uses multistrand rope as framework. In view of the complex working environment, sand blasting is performed on the surface the metallic framework to remove oil stain and rust stain, activate surface and increase bonding area.
(2) Mold Assembly: The steel mold is put into the framework after demolding. The temperature rises to 110°C.
3. Pouring of PU Sieve Sheet, chain extender: Dichloro diaminodiphenylmethane (MO2 CA). Due to the different production conditions, the pouring methods include manual pouring and mechanical pouring.
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