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In the BOPP coating production process, a certain amount of wetting agents and defoamers are often added to the pressure-sensitive adhesive in order to reduce the formation of bubbles and shrinkage defects. Now, taking defoamer 691 and HANERCHEM®T-70 as examples, the respective usage amounts and methods will be explained. (1): If the pressure-sensitive adhesive is based on pure acrylic acid, and the emulsifiers used are DOWFAX2A1 and HANERCHEM®DNS-501, or HANERCHEM®DNS-458 – in other words, when emulsifiers with good wetting properties are selected – the amount of defoamer 691 to be used is 0.9–1‰, while the amount of HANERCHEM®T-70 to be used is 1–1.2‰. The specific procedure is as follows: 1) For transparent BOPP emulsions, the amount of defoamer 691 used is 0.9–1‰ of the total volume of the emulsion, while the amount of HANERCHEM® T-70 added is approximately 1‰ of the total volume of the emulsion. An aqueous solution is prepared at a ratio of 1:8–10, and this solution is slowly added with stirring for 30 minutes. 2) For colored (usually yellow) BOPP emulsions, the amount of defoamer 691 used is 0.9–1‰ of the total volume of the emulsion, while the amount of HANERCHEM® T-70 added is approximately 1.2‰ of the emulsion volume. An aqueous solution is prepared at a ratio of 1:8–10, and after adding it, stirring is carried out for 30 minutes. (II): If the pressure-sensitive adhesive is based on pure acrylic acid, and the emulsifier is a system consisting of sodium dodecylbenzenesulfonate and short-chain reactive emulsifiers ； Or the pressure-sensitive adhesive is based on acetate copolymer – that is, when the wetting property of the emulsifier or latex system is not very good, the amount of defoamer 691 used is 0.9–1‰, while the amount of HANERCHEM® T-70 used is 1.5–1.8‰. The specific procedure is as follows: 1) For transparent BOPP emulsions, the amount of defoamer 691 used is 0.9–1‰ of the total volume of the emulsion, while the amount of HANERCHEM® T-70 added is approximately 1.5‰ of the total volume of the emulsion. An aqueous solution is prepared at a ratio of 1:8–10, and the ingredients are slowly added followed by stirring for 30 minutes. 2) For colored (usually yellow) BOPP emulsions, the amount of defoamer 691 used is 0.9–1‰ of the total volume of the emulsion, while the amount of HANERCHEM® T-70 added is approximately 1.8‰ of the emulsion volume. An aqueous solution is prepared at a ratio of 1:8–10, and after adding it, stirring is carried out for 30 minutes.