Coating knowledge: Causes and preventive measures of coating not drying or poor drying

Core tip: the coating does not dry or does not dry well: false dry, insufficient baking, too slow drying, low hardness related Description: paint film drying (self drying or baking) failed to completely dry and firm within the specified time, hand touch paint film has the feeling of moisture return, the overall hardness of paint film is low, failed to reach the specified hardness or there is the phenomenon of surface dry and interior dry In the serious cases, the phenomenon of back sticking appears after long-term sunlight exposure Related reasons: 1 The temperature of self drying or drying does not meet the requirements Generally speaking, the drying speed of two-component coating will be greatly reduced below 10 ℃, and the drying process of coating will be extremely slow or even stop Every 10 degrees of temperature reduction, Paint agent, top 10 Chinese wall paint brands Recommended introduction: interior wall paint and exterior wall paint can achieve beautiful, clean and pleasant effects, but the effects in different environments are different, so the color of the paint will be different There are ten brands of Chinese paint, ten brands of global paint, ten brands of Chinese wall paint, and ten brands of Chinese paint, Famous trademark of Chinese paint and coating In private rooms, most of us choose according to our own personality, personal hobbies and living habits The younger generation will choose the interior wall paint with rich colors and bright colors, while the older ones will have some working experience Paint Home News: paint does not dry or dry bad related statements: false dry, baking insufficient, too slow drying, low hardness related statements: paint film drying (since drying or baking) failed to completely dry and solid within the specified time, touch the paint film has the feeling of moisture return, the overall hardness of the paint film is low, failed to achieve the specified hardness or the phenomenon of surface dry and interior dry In the serious cases, the phenomenon of back sticking appears after long-term sunlight exposure Related reasons: 1 The temperature of self drying or drying does not meet the requirements Generally speaking, the drying speed of two-component coating will be greatly reduced below 10 ℃, and the drying process of coating will be extremely slow or even stop The time of chemical crosslinking doubled with every 10 ℃ decrease of temperature 2 The oven reaches the set temperature after warming up, but the heating will stop without holding for a period of time 3 One continuous spraying is too thick, resulting in abnormal solvent accumulation in the coating Especially in the continuous spraying with ordinary coating, 2 to 3 layers can be sprayed according to the specified requirements, but in order to pursue a better appearance or leave a margin for polishing, 4 or 5 layers are sprayed, so that although the paint film is thick, the drying performance of the coating is greatly reduced, and it is difficult to meet the drying requirements within the specified time 4 Curing agent and diluent are not used together When using auxiliary materials such as curing agent and diluent, we must adhere to the principle of matching, and can not use different brands of auxiliary materials to replace each other Even products of the same brand should be used according to the regulations of the manufacturer 5 The poor ventilation or high humidity in the self drying place causes the solvent contained in the coating not to volatilize normally, and the drying speed of the coating is greatly reduced 6 The bottom surface of the coating is not clean, leaving wax, oil, water and other substances that affect the drying In small area repair, there are a lot of problems in drying 7 Too much high boiling point solvent is added to the coating In order to improve leveling or rainy days to prevent "whitening", excessive high boiling point solvents such as "cyclohexanone" were added, which volatilized very slowly and remained in the film for a long time, affecting drying 8 Insufficient or excessive amount of curing agent Curing agent is not dispensable in two-component coating, it is crosslinked with resin in coating according to a certain proportion to form paint film If the curing agent is insufficient or redundant, it will cause poor drying It must be added according to the requirements of coating regulations 9 The diluent contains excessive water, alcohol and acid This situation is often seen in the use of cheap alternative diluents In particular, the use of various nitrodiluents instead of 2K diluents Such thinners will not only contain more impurities such as water and alcohol, but also may contain substances that react with curing agents, resulting in abnormal drying of coatings 10 Improper polishing Especially before the paint is completely dry, that is, the solvent in the paint is not completely volatilized, polishing will be started, which will not only cause the loss of gloss on the surface of the paint film, but also cause the abnormal drying of the paint due to the solvent erosion in the wax solution 11 The paint caused by some incorrect spraying process cannot be completely dry or fake dry For example, in the second coating of plain paint, if 2K plain paint is used as the primer, but no curing agent is added, and then varnish is sprayed on it, the result of such operation is that the paint film is not dry 12 Errors occurred in the color mixing process The typical phenomenon is that the film is soft due to insufficient resin, which is mainly caused by insufficient resin supplement in the process of fine adjustment or incorrect calculation of resin quantity in the process of adding formula This situation is rare In addition to the soft paint film, it is usually accompanied by low gloss, easy to scratch and fall off, and the fragments are easy to be powdered In color mixing, if the resin is used incorrectly, for example, 2K resin is used in the second pass of plain paint, it will not dry for a long time Preventive measures: the above reasons for the abnormal drying of paint film are some human factors As long as the construction is in accordance with the correct operating procedures, it can be effectively avoided Some are limited by conditions, which need to be solved after improvement of working conditions But the following basic operation requirements must be observed: 1 Coating and auxiliary materials must be used together 2 Select accessories with different drying speed according to different seasons 3 It is required to use standard containers for coating proportioning and add them according to scale scale scale 4 Keep good ventilation and circulation in paint baking room or paint spraying place 5 Do not use cheap and poor diluent 6 The mixing work of coating after adding curing agent and diluent cannot be ignored 7 Master the correct coating performance requirements, and do not force too thick coating 8 Polish after the specified polishing time 9 In the repair shop with conditions, infrared drying mode can be used to solve the problem of paint drying thoroughly by using the principle of infrared drying heating from inside to outside Solution 1 Seriously do not dry, or in case of wire drawing and sticking, or forget to add curing agent, or add wrong resin, remove the top coat to the bottom, and spray after the bottom is made again When removing such problem topcoat, it can be wiped off with thinner problem topcoat, and then it can be re sprayed after cleaning with degreaser 2 It is not very serious, that is, when the paint is only dry slowly, it can continue to heat up 60 ℃ in the baking room for 45 minutes 3 In most cases, the bottom with problems can be sealed with isolation primer, and then the top coat can be reapplied Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire 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