The improvement of the effectiveness of polyurethane defoamers in use can be considered from the following aspects:

1、 Reasonable selection of defoamers requires a thorough understanding of the technical characteristics of polyurethane defoamers, including their chemical structure, active ingredients, defoaming principles, and applicable polyurethane systems. This helps to find defoamers that match specific production needs when selecting. Ensure that the selected defoamer has good compatibility with polyurethane raw materials and other additives to avoid performance degradation or side effects caused by incompatibility.

2、 Scientifically determine the dosage, and through small-scale experiments, determine the optimal amount of defoamer to be added under specific production conditions. Generally, the recommended dosage is between 0.1% and 1% of the total weight of the product, but the specific dosage should be adjusted according to the actual production process and foam situation. Although increasing the dosage of defoamers may improve the defoaming effect to some extent, excessive use may have a negative impact on product performance, such as affecting the curing speed, mechanical properties, or appearance quality of polyurethane.

3、 Optimize the addition method by selecting the appropriate timing to add defoamers during the mixing or reaction process of polyurethane raw materials. It is usually recommended to add defoamers after the liquid is stirred evenly to ensure its uniform dispersion and optimal effect. For liquids that require long-term stirring, it is recommended to add defoamers in stages to ensure their uniform dispersion in the liquid and improve the defoaming effect.

4、 Pay attention to the details of the operation. After adding the defoamer, it should be thoroughly stirred with a mixer to ensure that the defoamer is fully mixed with the polyurethane raw material, avoiding local concentrations that are too high or too low. During the processing, pay attention to controlling the pH value of the liquid. Because high or low pH values may affect the effectiveness of defoamers, it is recommended to handle them within an appropriate pH range (such as 6-9). Due to the high molecular weight of polyurethane defoamers, direct pouring into liquids can easily lead to droplet deposition problems. Therefore, direct dumping should be avoided when adding, and drip or spray should be used instead.

5、 Regular evaluation and adjustment should be conducted, and the defoaming effect should be evaluated regularly during use. If the defoaming effect is not ideal, you can increase the amount of defoamer added appropriately or consider adjusting other ingredients in the formula. Based on the evaluation results and production requirements, continuously optimize the formula and process conditions to further improve the defoaming effect and product performance.

In summary, improving the effectiveness of polyurethane defoamers requires comprehensive consideration from multiple aspects, including rational selection of defoamers, scientific determination of dosage, optimization of addition methods, attention to operational details, and regular evaluation and adjustment. Through the implementation of these measures, it can be ensured that defoamers play their best role in the polyurethane production process, thereby improving product quality and production efficiency.