Discussion on various forms of polyurethane exterior wall insulation application
Discussion on various forms of polyurethane exterior wall insulation applications:
(1), on-site pouring polyurethane
The current practice of building is to cast polyurethane rigid foam into the cavity formed between the two walls. After the polyurethane is foamed, it is integrated with the inner and outer walls. When the polyurethane foams, it penetrates into the brick joint of the wall, and the new wall formed by the new one has a strong overall effect. Here, the foam itself is required to have a higher strength than the ordinary foam, and the wall should be sufficiently dried to avoid poor bonding. The other is to pay attention to the pressure generated during foaming to prevent deformation of the wall. In practice, the solution is to not have too much pouring amount per time to reduce the pressure generated by each foaming, and the wall is solidified to the highest structural strength. Foaming is carried out. Another way to cast polyurethane on site for exterior wall insulation is to pour the walls outside the building. The specific method is as follows: firstly, the structural bracket is pre-buried on the wall, and then the template is fixed on the bracket, and polyurethane is poured into the cavity between the wall and the template which has been reserved, and the next board is sequentially poured in this order. These structural supports can be the support points for the next protection and exterior decoration.
(2), on-site pouring polyurethane insulation
After the wall of the building is dry, the polyurethane can be sprayed directly on the surface. Generally, the thickness of the spray is about 4CM. It is necessary to use a high-pressure spray machine to make the surface as flat as possible. The polymer cement is scraped on the foam after the spraying, and then the outer decoration is added, or the colorant and quartz sand are mixed in the polymer cement, which can increase the strength of the protective layer and make the surface beautiful. The Canadian company is unique in that it first nails the wooden strips on the outer wall, sprays between each strip, then cuts the foam above the strips, and finally nails the decorative and protected sheets. On the wooden strip, this method is characterized by a flat overall shape, convenient decoration treatment, and is suitable for the heat preservation of a profiled building of a relatively low height.
(3), prefabricated insulation sandwich panel
Polyurethane sandwich panels processed on a continuous production line are generally used. The outer surface is often made of colored steel plate or aluminum plate, and the back side is mostly made of aluminum foil. When installing, first make the keel on the outer wall, then fix the plate on the keel, and some use the double-sided color steel plate as the wall material. The representative product of polyurethane sandwich panels for exterior wall insulation is the product of Robo, Germany, which weighs only 3.7 companies per square meter. Both beautiful and good thermal insulation.
(4) Filling and insulation of air core brick
The hollow part of these hollow bricks accounts for about 40% of the total volume of the brick. The brick body is mostly silicate material, and the polyurethane is filled in the cavity, which enhances the overall structure and greatly increases the thermal insulation effect. Now This material has been used in large energy-efficient buildings.
(5), exterior Wall Panel
A special polyurethane adhesive is usually applied to the dry exterior wall. The adhesive has high initial tack and good hydrolysis resistance. The pre-cut polyurethane board (clean surface, no sawdust) is attached to the outer wall, and the adhesive is applied on the outer surface of the polyurethane. The plaid is pasted, after it is cured, the polymer cement is applied, and finally the outer surface is decorated. This kind of practice is rare in China, but this process is very popular, except that the insulation board is made of extruded polystyrene foam board (XPS).
2, roof insulation
At present, the roof insulation of buildings in China is increasingly using polyurethane. The most common ones are spray foaming and sheet metal, and sandwich panels are also used. The following is a brief introduction:
(1) Spray foaming
It is common to spray polyurethane foam directly on the roof of the cement mortar layer, mostly at 4-5CM thick, 30-40kg/m3 density. After completion, the metal mesh is generally placed, the cement mortar is leveled, and then the waterproof layer. But there are also some waterproof layers, and then spray. In this way, there are many slope roofs, and the rigid polyurethane foam after spraying forms a tight overall without meeting, so the heat preservation effect is very good. If the subsequent construction is protected, the polyurethane foam can provide a certain auxiliary waterproof effect.
(2) laying polyurethane sheet
The cut polyurethane sheet coating adhesive is applied to the roof, and a certain pressure is applied to make the next board after curing. The gap between the board and the board is generally no more than 2CM. Finally, the mixed polyurethane is poured into the gap with a pouring bag, and the plastic film and the wooden box are pressed on it to make the polyurethane become a whole. See the plane, which is characterized by uniformity and evenness for subsequent construction. However, since the board has no crust protection, it is easy to absorb moisture.
This method generally employs a polyurethane sandwich panel of double-sided color steel plate, the surface layer of which can suppress a pattern similar to a tile shape. This makes the roof after construction look more beautiful. The tile-shaped sandwich panel is fixed on the keel of the roof, and is fixed on the roof by bolts and rivets. The joint is filled with sealant to prevent roof leakage and corrosion of the color plate. . In addition to the above three common practices, Canada's accompaniment is to use the wooden keel spray foam on the underside of the pointed roof, and then renovate it. This method is more suitable for the insulation of shaped roofs such as villa buildings.
3, the joint sealing of the building
There are gaps in the buildings, such as doors and windows and penetrating holes. These are the factors that consume energy in buildings. In the past, it was used to fill up the broken cement or bricks and then smear the cement. The internal voids caused by building imperfections became a hidden danger of building energy conservation. The polyurethane one-component rigid foam is placed in a pressure vessel barrel, and the valve is used to make the foam flow out during use, since the foam just emerging from the barrel is soft and can be arbitrarily deformed. In this way, the foam can be squeezed through the thin tube and the gap around the window, so that the foam becomes hard after being solidified, and can be slightly trimmed. Building penetration holes, such as air conditioning holes, cable holes, etc., can be used to fill it.
4. Insulation of building pipelines
There are two main types of building pipes that need to be insulated: one is the air supply duct of the central air conditioner, and the other is the heat pipe that the building needs to supply heat. Traditional air-conditioning air ducts are mostly rectangular ducts made of iron or fiberglass. There are many pipes that have poor insulation, even without insulation, which makes a lot of cold (hot) wind energy loss during transportation. The polyurethane soft-faced sandwich panels that have emerged in recent years have brought about a good solution to this problem. The board is a sandwich panel made of double-sided aluminum foil and polyurethane. It is very simple to process the pipe. It can be grooved with a 45-degree angle tool. Complete a three-way pipe with a cross-sectional area of ​​0.5 square meters, and it takes only less than 30 minutes for one person to operate. This duct has many advantages. It is only said to be energy-saving. This is mainly due to its good heat preservation and tight sealing (very small air leakage), which is unmatched by traditional materials. Of course, China's fire department has too high requirements on the flame retardancy of materials and the incompleteness of standards, making this material still limited in China. Another type of heat pipe in buildings is mainly used for heating in the northern part of China. The pipes in the building are mostly made of polyurethane rigid foam tiles. The prefabricated insulation tiles are buckled onto the insulated pipes, and the joints are painted and glued. Mix the mixture, or fix it with iron wire, and add the FRP protective layer on the outside. For the sake of beauty, often add the outer protective tube with aluminum foil, in addition to the appearance, it also plays the role of radiant heat.
In addition to the above products and applications, there are many other aspects of polyurethane energy in building energy conservation. For example, many household appliances, such as refrigerators, ovens, and water heaters, mostly use polyurethane insulation. In addition, solar water heaters cannot be separated from polyurethane insulation. To store hot water. Polyurethane is also one of the building sealant products. It can be seen that polyurethane has a lot to do in the field of building energy conservation.
Polyurethane rigid foam is the most commonly used polyurethane material in the field of building energy conservation. It is mainly used for the spraying of building exterior walls and polyurethane composite panels for building wall filling.
Polyurethane rigid foam spraying for exterior wall insulation is a new type of building energy-saving technology with good thermal insulation, stability, fire resistance, heat and humidity resistance, impact resistance, crack resistance and environmental protection. Due to the fast construction speed and high efficiency of the rigid foam polyurethane spray external insulation project, it has strong adaptability to the shape of the building, especially the heat preservation of the complex parts of the building structure node, and the maintenance of the decorative surface layer of the rigid foam polyurethane spray insulation system. Very convenient, it can keep its appearance and function in good condition after maintenance.
Polyurethane composite board is a color steel sandwich composite board. It consists of two-sided color steel profiled board and medium-automatic foamed rigid polyurethane. It can be widely used in exterior walls and roofs of various buildings. The best insulation material. It can be used in roofs and walls of various industrial buildings, warehouses, exhibition halls, gymnasiums, cold storages, purification workshops, etc., integrating heat preservation, heat insulation, load-bearing and waterproofing. In addition, the thickness of the wall using polyurethane sheet is much lower than that of the traditional building wall, and its thermal insulation performance is a multiple of the latter. Therefore, the polyurethane composite sheet has also been widely used.
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