Reasons for bubbles during stirring:
The reason why bubbles are generated during the mixing process of epoxy resin glue is that the gas introduced during the stirring process generates bubbles. Another reason is the “cavitation effect” caused by the liquid being stirred too fast. There are two types of bubbles: visible and invisible. Using vacuum degassing can only eliminate visible bubbles, but it is not effective in removing tiny bubbles that are invisible to the human eye.
Reasons for bubbles during curing:
This is because epoxy resin is cured by polymerization, which is a chemical reaction. During the curing reaction, the tiny bubbles in the epoxy resin system heat and expand, and the gas is no longer compatible with the epoxy system, and then gathers together to produce larger bubbles.
Causes of epoxy resin foaming:
(1) Unstable chemical properties
(2) Mixing when preparing thickener
(3) Foaming after thickener collection
(4) Slurry discharge process
Hazards of epoxy resin foaming during mixing:
(1) Foam causes overflow and thickener consumption, which will also affect the observed liquid level height.
(2) Bubbles caused by curing agent molecular amines will affect construction efficiency.
(3) The presence of “wet bubbles” will cause VCM gas phase polymerization, which is generally produced in the sticking kettle.
(4) If the bubbles are not completely removed during construction, bubbles will be generated after curing, and there will be many pinholes on the surface after drying, which will seriously affect the product quality.
How to eliminate air bubbles?
Commonly used defoaming agent product categories: silicone defoaming agents, non-silicon defoaming agents, polyether defoaming agents, mineral oil defoaming agents, high-carbon alcohol defoaming agents, etc.
When the temperature is low, the characteristics of most liquid substances Changes will occur, especially the viscosity of adhesive liquid substances will increase as the temperature decreases. Epoxy resin ab glue, as a typical liquid substance, has a significant increase in viscosity value due to the decrease in temperature. Therefore, during use and use, bubbles are difficult to eliminate, the flattening performance is reduced, and the increase in use time and curing time is not conducive to normal production and control. However, through the accumulation of many years of production experience, we have summarized some helpful experience to effectively solve and reduce the problems caused by the above problems. Specifically, there are the following four methods:
1. Job site heating method:
When the temperature at the job site drops to 25°C, effective heating of the job site is required to raise the temperature to a temperature suitable for glue operation (25°C~30°C). At the same time, the relative air humidity at the job site should be maintained at 70%. or so, until the temperature of the glue itself is the same as the ambient temperature before the glue can work and be used properly.
Warm reminder: This method is the most effective method, but the operating cost will be relatively high, please pay attention to cost accounting.
2. Boiling water heating method:
Cooling will directly reduce the viscosity value of epoxy resin ab glue and significantly increase it. Heating it in advance before using the glue will increase its own temperature and reduce the viscosity value, making it easy to use. The specific method is to put the entire barrel or bottle of glue into boiling water and heat it about 2 hours before using the glue, so that the glue temperature reaches about 30℃, then take it out, shake it twice, and then keep the A glue at a temperature of no less than 30℃ in warm water and use while heating. During use, take out the glue and shake it every half hour to keep the temperature and composition of the glue symmetrical. But be especially careful not to let the glue in the bucket or bottle stick to the water, otherwise it will lead to adverse or serious consequences.
Warm reminder: This method is simple, economical and practical, and the cost and materials are relatively easy. However, there are hidden dangers, which should be paid attention to.
3. Oven heating method:
Users who have the conditions can use epoxy resin ab to heat the glue a in the oven before using glue to avoid accidental contact with water. It is very simple. The specific method is to adjust the oven temperature to 60°C, then put the entire barrel or bottle of A glue into the oven to preheat, so that the temperature of the glue itself reaches 30°C, then take the glue out and shake it twice, and then put the glue at the temperature of Adjust to 30°C in the middle of the oven using preheated edges, but be careful to take out the glue and shake it for about an hour so that the glue always maintains a symmetrical temperature with the ingredients.
Warm reminder: This method will also increase the cost slightly, but it is relatively simple and effective.
4. Defoaming agent assistance method:
In order to moderately accelerate the removal of bubbles, you can also purchase a special defoaming agent for epoxy resin ab-added glue, and add A glue with a ratio of 3‰ inside, the specific method; directly add no more than 3% of the glue to the A glue heated by the above method. Special defoaming agent for epoxy resin AB glue, then stir evenly and mix with B glue for use.
Shanghai Orisen New Material Technology Co., Ltd
M: +86 18683776368(also whatsapp)
T:+86 08383990499
Email: grahamjin@jhcomposites.com
Address: NO.398 New Green Road Xinbang Town Songjiang District,Shanghai
Post time: Jan-07-2025