Eight application errors of polymer cement waterproof coating

Polymer Cement Waterproof Coatings (JS Waterproof Coatings) has been rapidly developed and widely applied from the end of last century to the beginning of this century because of its good physical properties, simple construction methods and the ability to construct on wet grass. However, in recent years, such products have a great potential for quality hidden dangers, to many construction units and management departments left a very bad impression and began to be skeptical, new products came out less than a decade ago to face with the poor quality of the elimination of products for the embarrassing situation, it is regrettable, the reasons in addition to the market low-cost competitive manufacturers deliberately sacrifice quality and construction process supervision is not allowed to let the proliferation of stealing materials, but also with this product improper application and many industry insiders have misconceptions about this product.1, the selection of latex and ingredient ratio of the understanding of the error JS waterproof coating is based on the synthesis of polymer latex modified cement and quartz sand as the main ingredients of inormerable gel material, the formation of the coating film in the basic to maintain the cement gel material on the basis of high strength, strong water resistance characteristics, as far as possible to improve its flexibility (i.e. elongation). At the same time, polymer latex also brings negative effect, that is, the decline of hardness and long-term water resistance and aging resistance, its negative effect size and the type and doping of latex used is closely related (i.e., the modified capacity of latex), the current market for JS coatings, there are two main types of latex - polyacrylate latex and polyethylene-ethylene acetate latex. The former has better ability of change than the latter, and the amount of usage to achieve the same performance is significantly less than that of the latter, and its negative effect is significantly smaller than that of the latter. But most people mistakenly think that JS paint should be the larger the amount of latex, the better, in the purchase of different manufacturers of products at the same price to compare which factory's latex consumption is large and choose. Therefore, some manufacturers or merchants in order to show that their products latex consumption is large, the purchase of latex raw materials mixed with water and then the preparation of JS paint, the quality of its products and the real JS paint is far from, and even more, some construction teams in the low-cost contract waterproofing project After the use of market-purchased polyvinyl acetate latex (commonly known as white latex) or polyethylene alcohol glue (commonly known as 107 glue) mixed construction, the consequences of which can not be described, seriously damaged the reputation of JS coatings. At present, the construction of a large number of JS coatings, the real use of polypropylene latex less than 10%, which is the main reason for JS coatings into the ranks of "poor" products.2, the classification of the use of insufficient understanding JS waterproof coating elongation size and latex dosing size directly related, but the size of latex doped directly affect the long-term water resistance of the coating, in order to solve this contradiction, engineering specifications and product standards Technical treatment is divided into two types of JS coatings, type I. for the latex dosing is large, the elongation rate requires more than 200%, for intermittent immersion of the engineering site (such as roof, exterior wall, etc.) to meet its deformation requirements. TYPE II. Type is slightly less latex dosing, as long as the elongation rate reaches 80%, to meet the deformation is small but has long-term water resistance requirements of the engineering parts (basement, toilet bath, etc.), but in many projects there is no distinction between the use, from the basement to roof are using a type, I. type or II. type, not only does not achieve the expected effect there are many quality hazards, disappointing.3, the relationship between coating thickness and construction number a good waterproof coating must also have a certain coating thickness as a quality assurance, in the "Roof Engineering Technical Specification" and "Underground Engineering Waterproofing Technical Specification", the basic thickness requirements of JS coatings are 1.5 to 2.0mm. In the actual engineering design and construction monitoring often only pay attention to the number of construction but ignore the final thickness of the coating, often see some design drawings only marked "using JS waterproof paint a few coatings" but does not indicate the thickness requirements. Site management also cares only a few times about painting. To some lack of integrity of the construction team drilled a hole, the paint added water to thin, than the design requirements to apply one or two times also get the praise of field managers, at a low price contracted to the project can also earn a lot of profits, excellent performance of products can not afford such damage.4, ignoring the importance of the impact of the on-site mixing state on the performance of the coating filmJS coating for two-component products, in fact, the product production of the last process - mixing phase, left to the site construction team to complete.I do not know, the two-group product mixing phase state is crucial to the formation of coating film performance, coupled with JS coating for powder-liquid two-parts is not as easy as other liquid-liquid dual-group products mixing and mixing, although the manufacturer's product instructions have instructions for the correct method of on-site mixing, but many construction team mixing process is perfunctory, some even no special mixer, the scene to find a stick hand-mixed. Very few people know the judgment and mastery of "phase end", so that the final form of coating performance because of mixing and phase incomplete and greatly reduced.5, the understanding of stretch strength error in the product standard of JS coating film stretch strength requirements are I.type ≥1.2MPa, II.type ≥1.8MPa, many people mistakenly believe that the higher the stretch strength, the better, in fact, in J In the extrusion performance test method of S coating, there is a standard maintenance 7 days after 50 degrees C heating maintenance 24h process, many paint products are in the process of thermal maintenance at 50 degrees C due to the volatile migration of plasticizers and make the extrusion strength rapid growth, indicating that these products in the exposure to the use of thermal aging performance changes quickly, life is not long. Therefore, for products with unusually high stretch strength, alertness should be raised and, if necessary, thermal aging rate testing can be done. Instead of one-sidedly arguing that the higher the stretch strength, the better.6, randomly set the tire base position in some engineering node details in order to avoid stress concentration to add tire base to spread the stress to reduce the coating cracking phenomenon. Therefore, the setting of the tire base position directly affects the use of the effect, should be the tire base closer to the grass-roots more can achieve the role of dispersed stress, and in fact, many projects randomly set the tire base position no one asked, to set in the middle of the coating for many, some projects will be laid on the coating surface, the author found this phenomenon in a construction site after asking the construction staff why the tire base exposed on the surface? The worker replied: "It is ironic to settle the tire-based money with the issuer".7, one-sided understanding of "can be understood in the wet grass-roots construction JS waterproof coating than other waterproof coatings are characterized by wet grass-roots construction, there is a humidity problem, not that any humid climate conditions or very high grass water content can be constructed, because JS paint latex is through volatile curing, excessive grass moisture content and too humid climate conditions on the curing film of the film adverse, will reduce the extension of the film. At the same time, the cement in JS coating is cured by water, too dry grass and climatic conditions, but also against cement curing, so in the hot and dry season when the construction of the grass to spray some water before construction. In fact, JS coating on the construction of the temperature and humidity range or some requirements, generally is the temperature at 5 degrees C to 35 degrees C, humidity in 50% to 70% is appropriate, regardless of temperature and humidity conditions forced construction, although it can also be filmed, but the coating performance is far away.8, the misunderstanding of water can be added most manufacturers in their product descriptions that the first brushing construction can be watered to dilute the paint and improve the penetration of the grass-roots to improve the bonding force of the grass-roots. Therefore, many people misunderstand that JS coatings can be freely added water, which is very harmful, JS coatings in two components than - poly ash ratio (polymer to cement ratio) and water ash ratio (water and cement ratio) is the manufacturer through a number of tests to determine, arbitrarily change one of the Ingredient ratio on the film performance of the impact is very large, the actual project any increase in the amount of powder and then casually add water to adjust the consistency of the phenomenon abounds, in fact, many projects are by using the name of JS paint to steal materials, so the application, JS coating prospects are slim.
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