Property Management Co., Ltd. Engineer.
A basic concept of rigid polyurethane waterproof insulation material Polyurethane (abbreviated as PU) is a polymer with urethane chain repeat structural unit made from the reaction of isocyanate and polyol. PU products are classified into two major categories: foam products and non-foam products. Foam products have soft, rigid, semi-rigid foams; non-foam products include paints, adhesives, synthetic leathers, elastomers, and elastic fibers (spandex). Polyurethane material has excellent performance, wide range of uses, and many types of products, among which polyurethane foam is most widely used.
P hard foam is mostly closed-cell structure, with good heat insulation effect, light weight, high strength, easy construction and other excellent features, but also has soundproofing, shockproof, electrical insulation, heat resistance, cold resistance, solvent resistance and other characteristics, widely used Refrigerator, freezer cabinet insulation, cold storage, refrigerated trucks and other insulation materials, buildings, storage tanks and pipe insulation materials, a small amount for non-insulated occasions, such as imitation wood, packaging materials. In general, the lower density PU rigid foam is mainly used as heat insulation (insulation) material, and the higher density PU rigid foam can be used as structural material (imitation wood) PU hard foam for building use is generally room temperature foaming, molding process easier.
According to the degree of construction mechanization can be divided into manual foaming and mechanical foaming; according to the foaming pressure can be divided into high-pressure foaming and low-pressure foaming; molding can be divided into pouring foaming and spray foaming.
PU rigid foam has excellent properties such as non-toxic, non-polluting, light weight, high strength, low thermal conductivity, high closed cell rate, impervious to water, moisture absorption, sound absorption, chemical corrosion resistance, and long service life. It has good adhesion with concrete, metal, masonry, wood, glass, fiber and other building materials. Among the building energy-saving materials, compared with developed countries, the ratio of PU hard foam materials used in construction in China accounts for a relatively low percentage of the entire rigid foam market. In the United States, hard foaming materials for construction account for more than half of the total amount of P hard foam materials, and China has only about 20%, which is far less than the average level of 4 Cambodian countries. According to China's building energy-saving plan, by 2010, more than one-third of the nation’s newly-built buildings will achieve the standards of green buildings and energy-saving buildings. At the same time, the total energy consumption of urban construction in the country should achieve 505% energy saving by 2020. Through further promotion of green buildings and energy-saving buildings, the total energy consumption of the entire society can achieve the overall goal of energy saving of 65%.
It is equivalent to the level of building energy consumption in developed countries at this stage. Therefore, PU rigid foam will be widely used.
2 Main components and production 2.1 Base material PU rigid foam consists of two components, A component is a polyol (combined polyether or polyester), B component is an isocyanate, add certain additives, two components into the spray coating during construction It is mixed and ejected in the machine and foamed and solidified in one minute to form a rigid foam with waterproof and heat insulation functions.
2.2 Production Process The PU hard foam adopts two methods of on-site injection foaming and composite prefabricated panels. Spray foaming uses two components to join together at the time of injection and immediately reacts to produce a PU hard foam c 2.3 PU hard foam material characteristics Water impermeability. HJ hard foam is a structure of dense microcellular foam closed porosity of 9:% or more, foaming the surface layer to form a smooth film, the closed cell rate of nearly 100% has a very high hydrophobicity. Therefore, it has high water vapor permeability resistance and good water impermeability. In the construction, the direct injection molding technology is adopted to make the PU rigid foam into a seamless shell, forming a complete impervious layer and fundamentally eliminating the water along the gap. Possibility of infiltration. In addition, it is firmly bonded to the base layer, and its bond strength can exceed the tear strength of the foam body itself, and does not separate from the base layer, and leakage of water along the interlayer is avoided.
Low thermal conductivity. The thermal conductivity is closely related to the internal pore structure of the material. The PU hard foam material is a dense and closed non-connected pore with a large porosity and little convection effect, so the thermal conductivity is small.
The thermal conductivity is only about 0 025, which is better than the polystyrene board. It is a good material for building insulation. It can be used for the insulation of the roof and exterior walls. When the thickness is 40mm, the required energy saving can reach 65%. HJ hard foam has low apparent density, high specific strength, high elongation, good impact resistance, no cracking, and strong ability to adapt to substrate deformation. Such as the apparent density of 35 ~ 40kgm3 its compressive strength between Q2 ~ 3MPa, the average elongation of 1 ~ 14%.
Chemically resistant. The PU rigid foam has good chemical stability under the action of common solvents such as benzene and gasoline, and dilute concentrations of acids, alkalis, and salt solutions, and will not cause mildew and corrosion.
Temperature resistance. PJ hard foam at a low temperature of 50 °C, the volume shrinkage rate of less than 1%, will not become brittle and cracking and other phenomena; at 120 °C, no significant change in volume and strength; higher temperature at 150 °C Below, the polymer will not degrade, so it can be used at high temperatures.
Light weight. The apparent density is small, the weight of the PU hard foam material after molding is 40kg/m1, and the weight is only 1.2~ when the thickness of the roof is 30~5mm. It is especially suitable for buildings with light large-span thin-shell structures.
Good bonding performance. It can bond with wood, metal, masonry, glass and other materials very firmly, and is not afraid of strong winds and freezing and thawing.
Good aging resistance. According to foreign projects that have been used for engineering summarization and research testing materials, the anti-aging period of up to 30 years is rapid, easy to operate and adaptable. The PU rigid foam is simple and easy to operate, and it is especially suitable for the basic surface construction with complicated shapes and vertical and horizontal pipelines. Due to on-site spraying, an integral waterproof layer is formed without seams, reducing maintenance work. It is suitable for new roofing or old roof repairs. In particular, repairs to old roofs are not necessary to eradicate the existing waterproof layer and insulation layer, and it is only necessary to remove ash and sand debris from the surface and spray it. The construction is simple and fast, the structure of the head is simple, and no special treatment is needed, which is conducive to rushing progress. In the case of unsuitable for on-site foaming, prefabricated composite panels can be used, and gaps between the panels can be filled with foam guns and the effect is also very good.
Good economic results. Commonly used waterproof materials generally separate the insulation layer and the waterproof layer, which not only has high cost, but also has a long construction period and poor reliability; while the PU hard foam once survives, the integrity is good, the secondary waterproof layer is not required, the construction speed is fast, and the overall economic efficiency is high. There are certain advantages.
3PU rigid foam in the building insulation on the construction process 3.1 roof spraying 31.1 construction conditions PU hard foam layer after the completion of the leveling layer construction, the construction of the ambient temperature of 15 ~ 35 °C is appropriate, relative humidity is less than 85%, the wind speed does not exceed The surface of 5m/s grass-roots level should be smooth, firm, and dry (moisture content less than 9%) without oil stains and clean. Pipes, equipment foundations and embedded parts that pass through the roof should be installed in place before the PU foam layer is applied. The connection between the basement and the protruding roof structure and corners of the grass-roots building shall be rounded or obtuse with a radius of 100 to 150. The water drainage opening of the organized drainage shall be made into a slightly lower pit.
31.2 Process flow Primary treatment d Check the moisture content of the screed layer. 1> Lay out additional layers, test spray, and spray> spray a fine-washing foaming machine – check construction quality ~ construction protection layer.
31.3 Construction Essentials Primary treatment. Clean the surface of the base layer and remove the protrusions such as mortar. The base layer can be peeled off, sanding, and cracks can be treated with polymer mortar. At the corners of drains, pipe roots, and parapets, where there are oil stains and rust, sandpaper and wire brushes are used to clean the brush and then wiped with a dry cloth and cleaned with a solvent.
Check the leveling layer moisture content. The isocyanate in the polyurethane foam reacts with water to form brittle materials containing urea, which seriously affects the bonding properties with the base layer. Therefore, the base layer must be dried (water content less than 9%) to lay additional layers. At the junctions of the gutters, trenches and roofs where structural displacements are likely to occur, additional layers of 200 to 300 mm wide coils are required to be laid; for the leveling layers, additional layers of 300 mm wide coils are to be applied. a. Use a high-pressure blower to blow out the dust particles on the surface of the base layer to ensure good adhesion between the PJ foam bubble and the base layer. b During the construction, the spray gun should move at a uniform distance of 0.6 m from the base layer. The spraying sequence gradually moved from the lower tuyere to the upper tuyere, the construction personnel faced the lower tuyere, and proceeded backwards; C layered spray construction, with a base thickness of 5mm, and then layered spray, with a total thickness of about 10mm per layer controlled at about 40, during spraying. Check the foam quality, the appearance should be smooth, no delamination, brittle, soft and closed hole is not good and so on. If any problem is found, it shall be promptly shut down and the cause must be properly handled.
During the spraying process, the compressed air cannot be interrupted. When the construction is intermittent, the material pump is stopped first. After the material in the waiting material pipe is blown, the compressor is stopped. Large-area spraying can be carried out in different sections, the joints must be well-integrated, and the coating should be even and smooth; d can be walked on after half an hour of spraying, and can be fully cured in 24 hours.
3.1.4 Checking the construction quality Check the construction quality and wait until the PU rigid foam is completely solidified.
The foam of the PU rigid foam layer should be uniform and tight, with uniform color and pale yellow color, no brittleness and softness, no delamination from the drum, and the closed porosity must meet the requirements.
The hard foam layer should be flat and its thickness can be checked vertically with a steel pin with a diameter of 1mm. Ten samples can be taken for each 100m roof, and the minimum thickness should not be less than the design requirement.
Two test blocks are made for each unit of the project roof to test their apparent density, compressive strength and thermal conductivity, and their performance indicators shall comply with the Technical Requirements for Directly Sprayed PU Rigid Foam Plastics for Roofing Waterproof and Heat Preservation (Q/Check). Whether the hard foam layer has leakage or water, and whether the drainage system is unobstructed, water storage inspection can be used, and the water storage time should not be less than 24h. 3.1.5 Construction of protective layer Hard foam layer can be used for protective layer construction after qualified inspection. The layer is made of 30-thickness 1:2.5 cement mortar, and the surface of the mortar is divided to prevent cracking of the cement mortar.When the shop is spread, the individual grids are sealed with a hard foam layer of 3 mx 3 m sub-seam sealing material. protection.
3.1.6 Precautions and product protection The hard foam layer shall be constructed only after all the other roofing works have been completed.
In order to avoid solar radiation and mechanical damage, the protective layer should be laid within 72 hours after the completion of spray foaming. During the laying of the protective layer, the hard foam layer should be protected to avoid mechanical damage and heavy objects and repeated stamping. When transporting cement mortar, planks should be laid.
3.2 Wall spray P hard foam can be sprayed on site and has strong adhesion to the wall base. Compared with other wall insulation materials, the material is not water-absorbing or water-permeable, and the integrity is good, there is no local cold bridge, so the wall The use of the material in the body to meet the wall insulation while solving the wall leakage problem.
3.21 Construction process Plug holes in the wall and use compressed air to blow off the dust on the wall.
The high-pressure spraying foaming machine sprays the PU rigid foam on the wall surface, and the thickness is generally 25~3mm. The thickness can be controlled by the hanging point threading method. After the spraying is completed, the local place is polished and leveled. 32 3.22 Advantages The outer surface of the wall is sprayed with 40 thick PU rigid foam, which increases the actual use area compared with other wall insulation materials, reduces the construction load, and effectively prevents the leakage of the outer wall.
4PU even more practical application of flat roof waterproof insulation: not on the roof and spray a color paint, as a protective layer; on the roof, sitting on the pulp paving brick.
Tile top slope roof: The PU rigid foam sprayed on the lower edge of the board, tile seat block on the board, will not slip.
Wall insulation: PU hard foam is more advantageous for wall insulation. Assembled large wallboard, sprayed in the intercostal space, good adhesion and tightness, both warm and waterproof.
For hollow blocks, foamed polyurethane can be sprayed into the holes and the plugs are full.
The wall of the freezer is especially good for spraying. The key to the current reform of the wall is that the insulation technology foaming polyurethane can make a great achievement.
Underground outdoor wall insulation and waterproof: It is the part where PU hard foam shows off. It can not only keep warm and waterproof, but also save other protective layers.
5 Conclusion P rigid foam waterproof insulation material main engineering characteristics are waterproof, anti-corrosion, light weight, easy to construct, although its existence of the construction is subject to temperature constraints, not easy to spray the formation of the shortcomings, but these shortcomings are easy to make up for. Because of its good durability, small thermal conductivity, and good moisture resistance, it has a very good energy-saving effect, whether it is used on roofs, walls, or underground walls. The material is environmentally friendly. The advantages of environmental protection are obvious and can reduce the construction process and save construction costs. Therefore PU rigid foam waterproof insulation material should be widely promoted in the construction of the project.
(Editor Zhang Xinmin) ※ Information. Technical Information ※ China's Mining Right Evaluation Criteria was officially released The China Mining Rights Appraiser Association officially issued guidelines for the assessment of Chinese mining rights, including the "Basic Principles for Mining Rights Assessment Technology", on the 1st. This marks the initial completion of China's mining rights evaluation criteria system.
The “China Mining Rights Assessment†consists of nine items including “Guidelines for Mining Rights Assessment Technologyâ€, “Guidelines for Mining Rights Assessment Proceduresâ€, “Guidelines for Mining Rights Assessment Servicesâ€, “Guidelines for the Preparation of Mining Rights Assessment Reportsâ€, and “Guidelines for Estimating the Base Dateâ€. The Guidelines will be fully implemented on September 1, 2008.
Wang Shenglong, deputy director of the Technical Committee of the China Mining Rights Appraiser Association, said that in the past three years, with the global expansion of the mining economy, the domestic mining rights assessment business has grown rapidly. One of its outstanding features is the assessment of business diversification, non-mining rights. The price assessment business is fully developed.
In the areas of investment and financing such as PO issuance, asset replacement, joint ventures, cooperation, mergers and acquisitions, corporate restructuring, and mortgage loans, as long as mineral resources are involved, almost all of them have the opportunity to assess the mining rights. Therefore, the deep-seated contradiction of “regulation is difficult to adapt to the market†is highlighted. The market places higher demands on mining rights assessment technology and professional ethics standards. The voice of the community to formulate mining right assessment criteria has become increasingly strong.
Wang Shenglong said that under the urgent need of the industry and the market, the first batch of China Mining Rights Assessment Criteria, including the aforementioned nine items, after two years of hard work, is a milestone in the construction of the self-regulatory system for the mining rights assessment industry in China. China has preliminarily established a relatively complete mining rights assessment criteria system that is suitable for both national conditions and the international standards.
1 After polishing and leveling the wall, hit the plastic expansion bolts and hang fine wire mesh, then paint the proportioned cement mortar to finish the wall decoration work.
2 The paint material on the wall surface can be mixed with mortar, cement mortar, etc., and other stucco constructions can also be applied on the wall surface.
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