Preparation method of foam inhibiting and antifoaming agent for polyvinyl alcohol (PVA) aqueous solution

Abstract

The invention relates to a preparation method of a foam inhibiting and antifoaming agent for a polyvinyl alcohol (PVA) aqueous solution. The foam inhibiting and antifoaming agent for the PVA aqueous solution consists of the following components in parts by weight: 30-50 parts of a main antifoaming and foam breaking agent, 1-5 parts of a synergistic antifoaming agent, 3-5 parts of a dispersing and wetting agent, 5-10 parts of a solubilizing agent and 40-60 parts of water, and is a mixture which is dispersed into water and is mixed by dispersing in a way of stirring at a high speed at the temperature of 80-95 DEG C for 30 minutes. The foam inhibiting and antifoaming agent prepared with the method is suitable for the preparation process of a high-concentration and high-viscosity PVA aqueous solution, and has excellent foam inhibiting and antifoaming functions by being added in the amount of 0.3-1 percent.

Description

technical field [0001] The invention relates to an antifoaming agent, in particular to a preparation method of an antifoaming and antifoaming agent for polyvinyl alcohol (PVA) aqueous solution, which is suitable for the preparation process of high-concentration and high-viscosity PVA aqueous solution. Background technique [0002] When PVA is formulated into an aqueous solution, it is first dispersed in cold water, and then heated and dissolved under stirring. Generally, it should be heated to 90°C~95°C. After the dissolution is completed, it should be kept at this temperature for about 30 minutes and kept stirring. Because PVA has the effect of surface activity, so can produce a large amount of foams along with stirring during the whole dissolving process, and along with the dissolving of PVA, the viscosity of aqueous solution increases and is not easy to eliminate. Especially when the concentration of PVA in water is greater than 10%, it is more difficult to eliminate. An...

AI Technical Summary

Problems solved by technology

Due to the high concentration and high viscosity of the prepared polyvinyl alcohol aqueous solution, in order to speed up the dissolution and uniformity of PVA in water, heating and stirring are generally used in production to dissolve, so the solution is easy to produce a large amount of foam, and it is extremely difficult to eliminate

The existing defoaming methods are as follows: 1. Adding defoaming agents, commonly used defoaming agents are generally some non-polar substances, such as methyl silicone oil, mineral oil such as white mineral oil and n-butanol, etc., and these oily The compatibility of the non-polar substance and the PVA aqueous solution system is poor, and it is easy to precipitate during casting and drying, resulting in oil spots and causing obvious defects in the film; due to the poor compatibility, the film is prone to problems in subsequent use. Such as heat sealing performance, printing performance, etc., will have adverse effects due to these oily non-polar substances

2. Use ultrasonic defoaming, which is characterized by adding defoaming equipment and devices, and this equipment can only eliminate the foam inside the solution, and it is difficult to eliminate the foam on the surface, so other means must be used to eliminate the foam on the surface of the solution

3. The natural defoaming of heat preservation and static defoaming is characterized by energy consumption and a long time, which is not conducive to production