Preparation method of alpha-cyanoacrylic acid low-whitening gel

Abstract

The invention provides a preparation method of alpha-cyanoacrylic acid low-whitening gel. The preparation method comprises the following steps: firstly, liquefying solid formaldehyde; mixing the liquefied solid formaldehyde with a solvent in a reaction container to obtain a mixture; dropwise adding ethyl cyanoacetate and a catalyst into the mixture, and carrying out polymerization reaction to obtain a reaction system; adding an organic solvent into the reaction system from the bottom of the reaction container, carrying out condensation reflux dehydration, and heating to start vacuum material pulling after the solvent in a reflux condensation pipe and a bottle is completely removed; stirring through a stirring unit after material pulling is completed, distilling and purifying after cracking is completed, and finally obtaining the alpha-cyanoacrylic acid low-whitening glue. According to the scheme, the steam pressure of white smoke during glue polymerization is effectively reduced, so that the whitening phenomenon is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of glue, in particular to a method for preparing α-cyanoacrylic acid low-whitening glue. Background technique [0002] α-cyanoacrylate adhesive is a kind of α-cyanoacrylate adhesive as the main component, one-component, low-viscosity, transparent, fast-curing adhesive at room temperature, also known as instant dry adhesive. Since it was discovered in 1955, it has been widely used because it can polymerize and solidify rapidly in the presence of traces of water, and can bond almost all materials except polyethylene and other inert materials in a very short time. One of the best room temperature curing adhesives. However, due to its high vapor pressure, the glue will produce white pungent smoke when it is polymerized and bonded objects, which will be condensed by the surrounding trace moisture to form a whitening phenomenon, also known as whitening. This whitening phenomenon seriously affects the aesthetics ...

AI Technical Summary

Problems solved by technology

This whitening phenomenon seriously affects the aesthetics of the bonding surface and limits the application range of α-cyanoacrylate adhesives to a large extent.

At present, when using α-cyanoacrylate adhesives, there are mainly the following methods to reduce whitening: 1. Selecting alkoxy cyanoacrylate adhesives with low vapor pressure can indeed reduce the effect of whitening, but due to Its price is high, and its performance is poor, it is difficult to meet the requirements of actual field use, so the market acceptance is gradually declining

2. Control the sizing environment and keep the temperature and humidity of the sizing environment within a constant range. This method puts forward higher requirements for the user's use environment, thus limiting its application range; 3. Reduce the amount of glue used , this method can reduce the whitening phenomenon in some cases, but when the amount of glue used cannot be reduced, this method will lose its effect

Images