Questions about You Should Know about HPMCMarch 23rd 2023
HPMC manufacturer-Application of redispersible polymer powder in Drymix mortar
1.Insulation board supporting mortar
The thermal insulation board supporting mortar is an important part of the external wall insulation, mainly the thermal insulation board adhesive and protective mortar. As a supporting material for the system, the components of the external insulation system must be regarded as a whole. Therefore, adhesives, insulation panels, protective mortars, fiber networks, screeds(if needed, or base), pins and decorative layers must be adjusted to each other as a system for overall testing and approval. It is not allowed to combine various formulations from different sources and does not constitute a façade insulation system as a system for overall testing and approval.
The exterior insulation system that emerged in the early 1970s was the addition of cement to the emulsion adhesive at the construction site. This composite material secures the expanded polystyrene sheet to the wall to be insulated and uses the same product and procedure to embed the fiberglass mesh into the reinforcement layer or the insulation board primer emulsion layer. In the early days, most synthetic resins were used for decorative coatings on the undercoat.
However, in practice, there are many problems when using this system. Especially when the emulsion adhesive is mixed with cement in the field, according to this process, the water cement ratio cannot be ensured to be the same and evenly mixed, so that the quality-stable adhesive and the bottom cannot be obtained. The coating, resulting in insufficient bond strength or flexibility, results in substandard performance and may even damage the building façade.
Since 2000, the energy-saving renovation work of the original buildings with poor thermal environment or high energy consumption in the heating area has begun. In 2005, key towns began to take part in the construction of thermal environment and energy-saving renovation. Because the thermal insulation board building energy-saving system has low thermal conductivity, light weight, high strength, waterproof, anti-seepage, easy construction and other excellent performance, it’s very attractive in energy-saving houses, and its market potential is huge, which is the one of the most growing fast products.
2. Advantages of thermal insulation board mortar
(1)high adhesion performance has good adhesion to substrate and heat-insulating foamed polystyrene board; (2)sufficient deformation ability(flexibility)and good impact resistance; (3)a variety of materials can be selected as the finish layer(such as organic synthetic coatings, silicone coatings, silicone coatings and cement based coatings) to improve the use and decorative effect of the coating surface layer;(4) light weight low requirements on the wall, can be directly used on concrete and brick walls; (5) environmentally friendly, non-toxic, saving a lot of energy loss; (6) excellent adhesion and surface strength through polymer modification, the extremely thin bottom layer has sufficient protection ability to cooperate with the reinforcing mesh to resist shock and vibration; (7) low shrinkage, no cracking, no shell, long-term weather resistance and stability; (8) use water to avoid random error of mixing mortar on site, stable quality; (9) excellent water retention and homogeneity, good construction performance and quick drying, early strength, high construction efficiency; (10) water resistance, alkali resistance, freezing and thawing resistance.
3. Construction application of thermal insulation board supporting mortar
The construction application of the thermal insulation board supporting mortar mainly includes the following contents;
Benzene board: density 15-20kg/㎡, shrinkage 150d, 0.15-0.25%, the seventh week has reached 0.1-0.2%(60 degree curing can also complete the shrinking process for more than 5d), thickness is 20-100mm, 50-80mm is more.
Glass fiber mesh cloth: alkali-resistant mesh cloth, immersed in lye for 90d,ultimate tensile strength, when the bonding method is fixed, it should be greater than 150N/M, and when mechanically fixed, it should exceed 250N/M. The mass per square meter of mesh is greater than 150g, and the quality of the alkali-resistant protective layer is 15-25%. The ultimate elongation of the mesh cloth should be as low as possible, and the mesh size is appropriate, so that the mortar inside and outside the mesh cloth can penetrate each other and be integrated, and the stress in the surface mortar is easy to transfer to the mesh cloth. The grid size is 3.5*3.5cm-5*5cm. Or more than 2m of ordinary mesh cloth, 2m below plus a layer of impact resistant mesh to strengthen.
1). Remove dust, oil and dirt from the surface of the wall. Check the flatness and verticality of the wall surface, check 2m by foot, the maximum deviation is not more than 5mm, the over-difference part should be cut or repaired with repair mortar;
2). The dry powder insulation board supporting bonding mortar is mixed and stirred evenly, which is the bonding material. It is recommended to use mechanical agitation. When mixing manually, the mixing time should be extended appropriately to ensure the uniformity of mixing. The amount of mixing should not be too much, and it should be used within 1 hour with the use of stirring.
3)The mixed adhesive material is applied to the polystyrene board according to the point sticking method, and then the polystyrene board is directly attached to the wall surface, and the thickness of the bonding layer is about 2-3mm. The point sticking method is about 0.5-0.6kg/m2. Polystyrene board paving should be flat.
4) The surface of the polystyrene board or the polystyrene granules of the polystyrene board adhered and smeared on the outer side of the outer wall should be as flat as possible. If necessary, it can be properly ground with coarse sandpaper, and naturally maintained for 12 hours before the next process can be carried out;
5) A layer of 2-3mm thick plaster is scraped on the surface of the polystyrene board, and then a glass fiber mesh cloth is laid. Then the second layer of plastering paste is applied on the surface of the glass fiber mesh cloth, and the glass fiber mesh cloth can be covered, and the thickness is about 1-2mm. The plastering mortar needs to be calendered before final setting. The total thickness of the protective layer is about 3-4mm, and the amount of material used is about 6kg/㎡.