Preparation method of novel polyurethane chain extender

Abstract

The invention discloses a novel low-viscosity liquid polyurethane chain extender PUCURE which is prepared by taking diamine MDA as a basic raw material. The PUCURE is matched with a polyurethane prepolymer in an MDI system; MDA / NaCl is dispersed in dioctyl adipate (DOA); in the presence of NaCl, the DOA reacts with the MDA at room temperature and an amino group in the DMA can be sealed to lose activity (reactivity); and when the reaction system is heated to 115-160 DEG C, a sealing agent is released and the released high-activity amino group rapidly reacts with the prepolymer to generate a high-strength elastomer product. A mixture of the PUCURE and the corresponding prepolymer can be stored for more than one month at a temperature of below 50 DEG C; compared with the traditional curing agents (MOCA, BDO, etc.), a product cured by the PUCUR has excellent dynamic performance; and the PUCURE has the characteristics of low viscosity and delaying property of the system, so that the PUCURE is applicable to opening pouring, liquid injection molding, spin casting, dipping and other technologies; in addition, the PUCURE is also applicable to production of large-sized products with complicated structures and occasions with requirements on microwave curing, high stability and unfixed operating time.

Description

technical field

[0001] The invention relates to a new process and a new product of a polyurethane chain extender. Background technique

[0002] The traditional polyurethane industry widely uses MOCA as a chain extender. The chemical name of MOCA is 3,3′-dichloro-4,4′-diaminodiphenylmethane. It is currently the most commonly used aromatic diamine chain extender, and its sales volume has always been dominant. MOCA is mainly used as a chain extension curing agent for TDI-based prepolymers. It is widely used in machinery industry, automobile and aircraft manufacturing, mining and sports facilities, and various light industrial manufacturing industries. It can also be used as a cross-linking agent for PU coatings and adhesives. Coupling agent, epoxy resin curing agent and high electrical resistance products, etc. In use, it is found that MOCA is easy to cure in the liquid prepolymer, and pre-curing will cause the system not to cure or the performance of the product to deteriora...