Whether the hottest CTBN is modified or not is not

2022-08-03
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Whether CTBN is modified or not, it is not as good as chx100 etbn

ctbn. There is a fatal defect in epoxy toughening, that is, specific conditions are required for the full connection (hereinafter referred to as "reaction") between the terminal carboxyl group (-cooh) and the epoxy functional group (-chch2o) in the epoxy resin; It is generally accepted in academic circles that after 80-120 minutes of reaction with epoxy resin under closed nitrogen filling conditions, adding appropriate catalyst and 120 ℃ temperature, the carboxyl end group is expected to be fully consumed by the reaction, and the chemical connection between CTBN and epoxy resin is also realized. Similar polyurethane (polyether) tougheners have the same problem because they depend on the connection between hydroxyl (-oh) and epoxy functional groups

the greening of epoxy plastic packaging is not only reflected in the fact that the toughening effect of the product itself has a great relationship with the setting of the whole system. If the curing conditions are not particularly suitable for the reactive connection between the end carboxyl group and the epoxy functional group, it will mean that the curing reaction of the epoxy resin (hereinafter referred to as "curing") will be given priority, and the connection between the end carboxyl 1 group and the epoxy will be insufficient and incomplete, which is obviously detrimental to the toughening effect

the specially designed curing system (such as CTBN toughening, anhydride curing agent and high-temperature curing at the same time) can match the curing conditions with the reaction conditions as much as possible, and establish the connection while curing. However, this system can only ensure that the reaction connection is not disturbed by the curing behavior to the greatest extent, and cannot fundamentally ensure that CTBN and epoxy can be fully and thoroughly connected. On the contrary, an ad hoc condition conducive to the reaction is often more suitable for curing, so as to accelerate the curing process. The probability of reaction and curing is completely random, and the stability of the application effect can be imagined. This special condition completely excludes the system that needs to be cured with amine and cured at room temperature, which greatly limits the application range of CTBN, an excellent RLP toughener

first, a copolymer of CTBN and epoxy resin is obtained through a special prepolymerization procedure, and then the copolymer is diluted into the epoxy resin according to a certain ratio in the process of use - the copolymer here is modified CTBN (called CTBN epoxy ester toughener by a domestic group), which is a common method at present. The facts show that, CTBN prepolymerization also specifies the product classification, technical requirements, test methods, inspection rules, product certificates, stacking and transportation of autoclaved lime sand bricks (hereinafter referred to as lime sand bricks). Many small enterprises directly aggregate into solids, so they cannot be used and have to give up. At present, a certain enterprise in the United States can gather prepolymers with a rubber content of 50% (i.e. 50% of nitrile rubber and 50% of epoxy resin in the product), and a certain enterprise in Europe can gather prepolymers with a rubber content of 40% (i.e. 40% of nitrile rubber and 60% of epoxy resin in the product). These prepolymers have reasonable viscosity and can be directly added to epoxy resin when used, but they contain 50%--60% of specific types of epoxy resin. These resins may not match the resins used by consumers. Only enterprises with considerable strength can obtain prepolymers that are customized for enterprises and the same as the epoxy resin they use

the special prepolymerization procedure (or the production process of modified CTBN) can not avoid the contradiction between curing and reaction. The connection degree between nitrile rubber and epoxy in these prepolymers is unknown. However, all prepolymer products provide acid value data to prove the adequacy of carboxyl end reaction in the product. In addition, what is more serious is that CTBN molecules can "self polymerize" through the connection of epoxy molecules during the prepolymerization process, forming epoxy nitrile rubber copolymers with very different molecular weight and rubber content. These connected molecules with complex structure cannot be separated again in use. Therefore, it is internationally recognized that the main reason for the instability of toughening caused by CTBN is the uniformity of the distribution of nitrile rubber in the system

chx100 etbn is epoxy terminated reactive liquid nitrile rubber. Its effective content is 100%, its molecular weight is very uniform, the functionality of epoxide in the product is determined (not less than 1.8), and its acid value is less than 1.5. It can be fully mixed with any kind of epoxy resin without reaction, and there will be no delamination after mixing, so that the distribution uniformity of nitrile rubber in the epoxy system reaches the most ideal state. Since the active end group is epoxy, the conditions for promoting the connection between nitrile rubber and epoxy resin are completely suitable for the curing conditions you set. When you choose any curing agent and any curing temperature, as long as the curing process can be carried out, the connection process can be carried out synchronously and smoothly

chx100 etbn is an independent intellectual property product of Beijing Dwight Chemical Technology Co., Ltd. the product does not contain halogen or phosphorus, and fully meets the environmental protection requirements. The humidity is 20% and 80%. (end)

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