[China Epoxy Resin Industry Online] May 26, 2005: In this year of the refined development of epoxy resins, the development of high molecular weight epoxy resin products is also facing increasing performance requirements.
Experts from China Epoxy Resin Industry Association pointed out that on the one hand, this situation raised the production threshold of high molecular weight epoxy resins, and on the other hand, it also brought opportunities for the development of this product.
At present, the domestic high-molecular-weight epoxy resin production method adopts a two-step method, which is generally formed by repolymerizing liquid low-molecular-weight epoxy resin and bisphenol A under the action of a catalyst.
Among them, high-purity ECH and refined BPA must be used in the manufacture of liquid low-molecular-weight epoxy resin, and the process must be strictly controlled to clean the alkali and salt in the resin to minimize the content of inorganic and organic chlorine.
The catalysts used are roughly divided into three categories: basic compounds such as NaOH, LiOH, hexahydropyridine, etc.
, inorganic salt compounds such as LiCl, KI, etc.
, and organic phosphine compounds such as triphenylphosphine, tributylphosphine, and quaternary phosphine salts.
In order to meet and improve application performance requirements, experts believe that the following links should be paid attention to.
In epoxy/phenolic resin coatings, the commonly used high molecular weight epoxy resins are 607#(Epikote1007) and 609#(Epiklte 1009).
Although generally low-molecular-weight or medium-molecular-weight epoxy resins can also be used, the ring formed by them The chemical resistance, toughness and sterilization ability of the oxygen/phenolic resin coating film are difficult to meet the requirements.
For food can coatings, the epoxy resin is required to have a certain amount of long-chain structure and a certain amount of branched chain structure.
It also requires a relatively concentrated molecular weight distribution.
The lower the low molecular weight epoxy, the better, and no colloidal particles are allowed.
generate.
Only such epoxy resin can form a multilayer network structure with Resol phenolic resin at high temperature and cure quickly and uniformly.
(Our reporter Shuzhi)
