1.The introduction for JS Polymer Cement Waterproof Coating(KD-C03) selection and ratio of ingredients
The basic principle of JS waterproof coating is based on the synthesis of polymer latex modified cement and quartz sand as the main components of inorganic cementitious materials, the formed coating film in the basic maintenance of cement cementitious materials of high strength, strong water resistance, but also flexible (that is, the elongation).However, polymer latex also brings negative effects to cement-based materials, that is, the decrease of hardness and the long-term water resistance and aging resistance, and the negative effects are closely related to the type and amount of latex used (namely, the modification ability of JS).
At present, there are mainly two types of latex used in JS coating on the market -- polyacrylate latex and polyvinyl acetate latex. The former has better modification ability than the latter, and the amount of the former to achieve the same performance is significantly less than the latter, and its negative effect is also significantly less than the latter.But most people mistakenly think that JS coating should be latex dosage is bigger the better, in the purchase of different manufacturers of products with the same price to compare which product latex dosage is large and choose.
Therefore, some manufacturers or businesses in order to show that its product latex dosage is large, will buy the latex raw materials mixed with water to prepare JS coating, its product quality is far from the real JS coating.More very person, some construction team in the low contract waterproof project, the use of the city to buy polyvinyl acetate latex (commonly known as white latex) or polyvinyl alcohol glue (commonly known as 107 glue) mixed with the construction, its consequences can not be imagined, seriously damaged the reputation of JS coating.At present, in the JS coating widely used in construction engineering, less than 10% of the polyacrylate latex is really used.
2.Insufficient understanding of classification usage;
The elongation of JS waterproof coating is directly related to the amount of latex, but the amount of latex directly affects the long-term water resistance of the coating.In order to solve this contradiction, engineering specifications and product standards of technical processing is JS coating type: type Ⅰ for latex dosage is bigger, elongation requirements above 200%, used in intermittent flooding engineering parts (such as roof, metope, etc.) to meet the requirements of its deformation is larger;Ⅱ type for latex dosage slightly less, elongation, as long as 80% to meet the small deformation has a long-term water resistance requirements of the project site (basement, toilet bath room, etc.).But there is no distinction between in many engineering use, from the basement to the roof are using a type (type Ⅰ or Ⅱ), not only cannot achieve the desired effect, can also lead to a lot of quality hidden trouble.
3. The relationship between coating thickness and construction times;
Even the best waterproof coatings must have a certain coating thickness as a quality guarantee. In "Technical Specification for Roofing Engineering" and "Technical Specification for Waterproofing of Underground Engineering", the basic thickness of JS coating is required to be 1.5-2.0mm. However, in the design and construction monitoring of actual projects, often only pay attention to the number of construction passes but ignore the final thickness of the coating. It is often seen that some design drawings only indicate "How many coats of JS waterproof coating are used" but do not indicate the thickness requirements , And the site management only cares about painting a few times. This gives some untrustworthy construction teams a chance to take advantage of. After adding water and diluting the paint, apply it one or two times more than the design requirements. It will also get the approval of the on-site management staff. It can earn money after the project is contracted at a low price. To huge profits.
4. Ignore the importance of the on-site mixing state on the performance of the coating film;
JS paint is a two-component product, which actually leaves the last process of product production-mixing and phase separation, to the on-site construction staff to complete. As everyone knows, the mixing and phase separation of two-component products is crucial to the formation of coating film properties. JS paint is a powder-liquid two-component, which is not as easy to mix and separate as other liquid-liquid two-component products. Although each manufacturer’s product manual has the correct method of on-site mixing, many construction teams are perfunctory in the mixing process Some people don’t even have a special stirrer. They find a stick and mix it by hand on site. Very few people know the judgment and mastery of the "phase separation end point", so that the performance of the final formed coating film is greatly increased due to the incomplete mixing and phase separation. discount.
5. Misunderstanding of tensile strength;
In the product standards of JS coatings, the requirements for the tensile strength of the coating film are type I ≥ 1.2 MPa and type II ≥ 1.8 MPa. Many people mistakenly believe that the higher the tensile strength, the better, but it is not. In the tensile performance test method of JS coatings, there is a standard curing process of 7 days followed by heating and curing at 50°C for 24 hours. Many coating products have a rapid increase in tensile strength due to plasticizer volatilization and migration during this process, indicating that these products The thermal aging performance changes quickly during exposure and the life is not long. Therefore, you should be alert to products with abnormally high tensile strength. If necessary, you can do a heat aging retention test instead of one-sided thinking that the higher the tensile strength, the better.
6. Set tire base position freely;
In the details of the joints of some projects, in order to avoid stress concentration, a tire base layer is added to spread the stress and reduce the cracking of the coating. Therefore, the setting of the tire base position directly affects the use effect, and the closer the tire base is to the base layer, the better the stress can be dispersed. In fact, in many projects, the position of the tire base is set at will, and most of them are set in the middle of the coating. Some projects actually lay the tire base on the coated surface.
7.A partial understanding of "Construction in wet base";
JS waterproof coating than other waterproof coating characteristics can be in damp base construction, but also have a question of degree of humidity, is not to say that any humid climate conditions or very high moisture content conditions are construction at the grassroots level for JS latex in the coating is through volatilization curing, high moisture content at the grass-roots level and too humid climate conditions adverse to the curing of latex film, will reduce the coating elongation.At the same time, the cement in JS coating is cured through hydration, too dry base and climate conditions are unfavorable for cement curing, so in the hot dry season construction and the base should be slightly sprayed with some water before construction.In fact, JS coating on the construction of temperature and humidity range or there are some requirements, the general temperature in 5 ~ 35℃, humidity in 50% ~ 70% is more appropriate, regardless of the temperature and humidity conditions to construct JS coating at will, although it can be into a film, but the film performance is far.
8.Misconceptions about adding water;
Most manufacturers in its product specifications, in the first coating brush construction can be diluted with water and improve the penetration of the grassroots, in order to improve the adhesion of the grassroots.So many people will be misunderstood as JS coating is free to add water, this is wrong.The ratio of two components in JS coating -- the ratio of poly (ash) (the ratio of polymer to cement) and water-cement (the ratio of water to cement) are determined by the manufacturer through many experiments. Arbitrarily changing one of the component ratios will have a great impact on the film performance.In the actual project, arbitrarily increase the amount of powder and then casually add water to adjust the consistency everywhere, which is actually in the name of JS coating to steal the real material reduction.
Add: Taitou waterproof Industry Zone, Shouguang,Shandong ,China