Cement particle board Gypsum board Wood particle board (urethane glue) Outdoor waterproof MDF Oriented strand board (phenolic glue) standard requirement 60% After 24 hours of water immersion, the rate of decline in flexural strength <40% <20% Thickness expansion rate after 24 hours of water immersion =<2% <1.6% 8% after 24 hours of water immersion 8-10% 12-13% In addition, Japan's water resistance requirements, in the Japanese JIS A5422 standard for cement panels for external walls, it is stipulated that after 3 hours of water immersion, and then dried at 80 ° C for 1.5 hours, the plane deformation of 320 mm × 150 mm specimens shall not exceed 3 mm. The requirement, this actually reflects the requirement for the degree of permanent deformation of the board due to moisture. For water absorption, the requirements specified in this standard are equivalent to a water absorption of 24 hours and should not exceed 1 g/c. These requirements can be achieved on Japanese cement-coated exterior wall panels to ensure the quality of the exterior walls of the building. Accelerated aging test method test results 1 The test piece was first immersed in 20 ° C for 48 h, and then 50 times 24 h freeze-thaw cycle test (-20 ° C frozen 16 h, +20 ° C melt 8 h) MOR retention rate is 90% 2 Soak the test piece in 60 ° C water for 6 months MOR MOE retention rate is 66-83% 3 Three freeze-thaw cycles were carried out according to the French V313 particle board standard (12 °C frozen for 24 h, +20 °C for 72 h, 70 °C for 72 h) Thickness expansion rate is 0.2-1.0% IB retention rate is 55-80% 4 70 freeze-thaw cycles according to the CEN standard of European cement particle board (3h at -20°C, 3h at +20°C) MOR retention rate is 89% Through the above series of rigorous tests, it is not difficult to find its outstanding durability characteristics, which can fully meet the needs of the construction industry for non-bearing walls. use thickness density Anti-folding load Impact resistance Grip force Reverse nail head Exterior wall hanging board 18mm 980kg/ >885N 500g weight, 1.7m drop Nail head Φ5.5>1568N Roofing lookout 18mm 1050kg/m2 >2107N 1000g weight, 4m drop Nail rod Φ3.5>1470N According to the regulations specified in the table, the flexural strength of the external wall hanging board is only 4Mpa, and the roofing board is only 9.5Mpa. In fact, cement particleboard only needs to adjust the formula and process properly, and it is easy to exceed these requirements. However, they think that the strength index is sufficient from the requirements of use. If the strength is further increased, it will affect the convenience of construction. Balance the results of coordination. In addition, the different nail holding requirements for different uses are also completely based on the actual construction needs. Since the wallboard is nailed to the wooden lining, there is no need to hold the nail force, but the plate should be unplugged. The requirement is that the roofing panel is to be fixed to other components, so the nailing force is required. The scientific attitude of Japanese companies based on reality is very worth learning. Gypsum board Gypsum fiberboard Gypsum particleboard Fiber cement board Calcium silicate board Cement particle board 23°CRH50%-90% linear rate of change mm/m 0.3-0.5 0.6-0.9 0.7-1.1 Natural curing Pressure curing Pressure curing Natural curing 1.5-1.7 0.4-1.0 0.4-1.2 1.8-2.5 Countries all over the world are working hard to improve methods. At present, Japan mainly adopts the method of adding silicon-containing materials and pressing steam treatment to improve it; in Europe, it mainly studies the new paint to make the inside of the plate tightly insulated from the air, and has achieved obvious effects. It is believed that with the development of science and technology, the performance of cement particleboard will continue to overcome the weaknesses, so that many outstanding advantages can be more exerted.
Paper Products have become an indispensable part of our lives. Paper products can be found everywhere, such as Paper Boxes , Printed Matters, Paper Notebooks, Paper Jewelry Boxes, etc. These are all made from paper, the advantage of paper products is that they are inexpensive but strong in functionality, the types of paper are differentiated by the use, such as whiteboard paper, coated paper and so on.
Our team has a lot of experience in the R&D and production of paper products. We can provide OEM services according to customers` design requirements.
Paper Boxes
Paper Jewelry Boxes
Paper Products Paper Packaging Boxes,Paper Gift Box,Plain Paper Notebook,Small Cardboard Gift Boxes Triple C International (Shenzhen) Co.,Ltd. , https://www.CCC-Triple.com
2. Water resistance with good water resistance for exterior wall materials is a prominent feature of cement particleboard relative to gypsum board and wood-based panel, and it is therefore determined that it can be applied to the exterior wall of a building. The index reflecting the water resistance of the material is mainly the flexural strength and the thickness expansion ratio after 24 hours of water immersion. From the comparison of the water resistance indexes of several kinds of plates shown in Table 2, it can be seen that the cement particle board has excellent water resistance.
Table 2 Comparison of water resistance indexes of several plates
3. Highly Durable Durability of building materials refers to the ability of building components made from this material to maintain its usableability for a specified period of time. It is a problem that the construction industry pays close attention to when selecting materials. Since the 1960s, the world has conducted extensive tests on the durability of cement particleboard. Mr. Dinwoodle of the British Institute of Building Research spent 15 years measuring it. In 1990, he published his results on the durability of 10 types of cement particleboard produced in 8 countries. Figure 5 and Figure 6 compare the creep resistance of cement particleboard and several other plates. The difference is that Figure 5 reflects the creep variable when the relative humidity is 65% and the load stress is 30% of the ultimate stress of the material; while Figure 6 reflects the relative humidity when the relative humidity is 90% and the load level is the same as above. The creep variable α. (Note: The relative creep variable is the ratio of the difference between the final creep value and the initial deformation value to the initial deformation value.) Table 3 shows the results of the accelerated aging test on the cement particle board. (For details, see "New Building Materials Information", 2000.11, page 34)
Table 3 Accelerated aging test results of cement particle board
4, in line with the development requirements of ecological building materials According to the requirements of ecological building materials, the following aspects can be explained from the following aspects of cement particle board should be encouraged to develop in the 21st century.
- The raw materials of the cement particle board can utilize some silicon-containing industrial wastes, such as: electric dust-removing fly ash, water-quenched steel slag, and the like. The amount of incorporation should be based on the performance requirements of the sheet. According to the latest research, up to 35% of the total raw materials, this has reached the state's preferential conditions for the use of industrial waste.
- Due to the semi-dry method in the manufacturing process, not only water is saved, but also energy consumption is reduced, and there is no danger of wastewater pollution. Solid waste such as trimming is allowed to be reused after treatment, and the final discharge can be controlled at about 1%, which greatly reduces the environmental load.
- Cement particleboard does not contain factors that are harmful to human health, such as free formaldehyde, radioactivity and light radiation; and its excellent thermal and acoustic insulation properties provide energy-saving and comfortable living environment for humans. The thermal conductivity of molded cement particleboard produced by Japan Nichiha Co., Ltd. is about 0.18-0.21 W/m·k, and its thermal insulation performance is four times that of mortar clay brick masonry. Sound insulation performance thick 18  plate can block 34dB (A) 100HZ noise; Netherlands Eltomation company provides 12  thick plate composed of 100  thick composite wall panel can block 45dB (A) noise test results, indicating that it is completely Meet the sound insulation requirements of the partition wall.
In view of the floods, sandstorms and desertification in China in recent years, the importance of protecting forest resources has been greatly deepened throughout the country. Some people may still use wood materials for cement particleboard to cope with their development prospects. First of all, we must understand that the major decisions of the Party Central Committee and the State Council on the implementation of natural forest protection projects are very wise and timely; and while understanding the important role of forests in protecting the ecological environment, we should not ignore the fact that forests are an important resource for human life and production. And it is the only renewable resource in the world's four basic materials - steel, cement, plastics and wood; it is the least energy-consuming material in development and utilization, only 1/10 of cement and 1/20 of steel; At the same time, it is a material that can be degraded after disposal and is convenient to handle. In the current situation that steel and petroleum resources on the earth are also facing the danger of depletion, it is undoubtedly a strategic move to make full use of renewable resources. Furthermore, the protection and utilization of forest resources are both antagonistic and unified, and protection is also used for better use, and to provide funds for protection and people's conceptual protection. At present, China's Jiangsu, Shandong, Hebei and other provinces have realized the great economic value of plantation forests through utilization, which has stimulated the enthusiasm of afforestation. The area of ​​planted forests is increasing at a rate of 15-20% per year, forming a sustainable development. The plain forest zone is the best example of the unity of the two. The woody material of cement particleboard is just these artificially planted fast-growing trees, so there is no need to worry that the development of cement particle board will violate the requirements of forest resource protection.
5. The strength and ease of construction are better unified. As the building board, the load requirements of the components should not be satisfied in terms of mechanical properties; the convenience of the construction process should also be fully considered. The cement particle board combines the respective characteristics of cement and wood. On the one hand, the cement has sufficient mechanical strength, such as flexural strength, generally in the range of 9-15 MPa, and can withstand a wind pressure of 55 kg/e, which is equivalent to a tropical wind of 140 km/h. The wind load caused by the storm on the wall; also has a certain impact strength. The 120mm thick composite wall panel which was composed of 12mm cement particle board also has a certain impact strength. The 120mm thick composite wall which was composed of 12mm cement particle board The plate was continuously impacted 10 times with a 10 kg sand bag at a height of 1 m, and no damage occurred. On the other hand, it also exerts the characteristics of wood shavings, which overcomes the brittleness and difficult processing of cement sheets. It can be used in construction methods like wood-board, such as sawing, drilling and sanding, and even allowing pre-drilling and direct nailing, which brings a lot of convenience to the construction.
From Nichiha Corporation of Japan, different indications for the different performance requirements of cement particleboard may give some inspiration (see Table 4).
Table 4 Nichiha Product Performance Requirements
Everything has two sides. Compared with other types of building light panels, cement particleboards have weaker dimensional stability (see Table 5), which greatly affects the application of cement particleboard on the wall.
Table 5 Comparison of dimensional stability of several inorganic bonded wood-based panels
3. Process and equipment of molded cement particle board The process flow of the annual production of 30,000 tons of molded cement particle board production line developed by Sufula Co., Ltd. under the support of many domestic research institutes.
The production line is based on the basic technology of the production of ordinary type plates, and incorporates many of the latest international technologies in the 1990s, so that it can adapt to the molding process requirements and has obvious technical innovation features.
1. The process formula has been significantly improved. The new formula uses industrial silicon-containing waste residue, which accounts for more than 30% of the total raw materials, such as electric dust-removing fly ash and water-quenched steel slag. Its main purpose is to make CaO formed by cement hydration process further react with SiO2 to form calcium silicate hydrate CSH.
SiO2+CaO+H2O CaO •SiO2•PAN>H2O
Thereby reducing the adverse effect of the ettringite formed by the cement hydration process on the dimensional stability of the sheet; at the same time, it is also beneficial to reduce the pH value of the sheet and reduce the erosion effect of the alkaline substance on the wood shavings. The use of industrial waste can not only reduce the cost of raw materials, but also meet the fiscal and tax incentives that the state encourages to develop.
In the process formula, the technical feasibility of artificial fast-growing tree species, including poplar, Chinese fir and masson pine, as wood raw materials is also studied. This is in line with the national industrial policy of protecting natural forests and developing plantations, and is a comprehensive synthesis of plantation resources. Utilization and value added provide new ways.
2. The slab section of the three-layer structure is used to ensure the appearance quality of the concave and convex surface. The fineness and surface thickness of the surface layer are higher than the common type. The three-layer structure is more advantageous than the gradual structure. Adapt to the needs of the process. In addition, the requirement for lightweighting of the sheet material can also be achieved by special treatment of the core material, which is difficult to implement in the gradual structure. Especially in the current development trend of higher degree simulation and increased depth of profile, the three-layer structure is widely used internationally.
The three-layer structure slab requires two sets of mixing systems and three paving heads on the process layout, respectively.
Table, core material mixing and paving. This also caused a slight increase in initial investment in equipment.
3, the new slab paving system slab paving system is the key host of the production line, which is related to the thickness precision, density uniformity of the formed sheet, the appearance quality of the molded surface, the process flexibility of the production line and the coordination of the front and back processes. Wait. In the past, China's cement particle board production plant mainly used wood chipboard production technology, using air flow paving system, slab error is large, 12mm board should reach ±1.0mm, and some factory 28mm board even up to ±3.0mm; therefore, it has to pass sanding To correct the thickness error, this will inevitably increase production costs. In foreign countries, only the plates that need to be surface veneer are only slightly sanded before leaving the factory. The number of sanding plates is only 20% of the total output. In addition, when the deep mold paving machine is used, "cavity defect" is also generated, which is a problem that must be considered when designing the paving machine for molding plate production. The newly designed paving machine draws on the latest experience from the 1990s and has made significant structural improvements, including the use of mechanical paving heads, feedback interlocking of paving speed and paving volume to increase silo weighing. The system can increase the thickness accuracy to the level of the 1990s, and it can meet the construction requirements without sanding. The slabs after paving will also be automatically weighed one by one to eliminate excess products at any time, which can ensure the uniformity of the density of the plates.
The new paving system adopts the lower formwork layout, which can adapt to the production of molded plates and the production of ordinary plates; it can adapt to the production of shallow molded plates, and can also adapt to the production of deep molded plates. Process flexibility.
Steel backing and FRP formwork are an integral part of the paving system. Due to the cold pressing process, the production cycle of the mat and the template is long. Therefore, in order to ensure a certain daily output, the number of spare mats and templates required is large, and the flatness of the mat is improved, and the pattern of the template surface is novel. Sexuality, the resistance to deformation under the action of cyclic pressure and heat load is very high, which is a factor that can not be ignored in ensuring product quality.
4. The forming pressure is increased compared with the ordinary type plate process. The cold pressing method is still used in the process, but the process requirement of the molded plate is to increase the surface pressure from the original 3.0Mpa to 5.5Mpa. This is to ensure a clearer profile profile, as well as to improve the dimensional stability of the product due to changes in the formulation of the raw material. To this end, the thrust t position of the press is increased from 1300t to 3000t.
In the process, before the forming and pressing, a pre-pressing process is added than the ordinary plate process, and the purpose thereof is to coordinate the production of the beat, and on the other hand, to increase the strength of the slab and the molding quality of the surface of the product.
5. Increasing the saturated steam curing process This is firstly to improve the dimensional stability of the sheet, because the aforementioned silicon calcium is reacted, and the condition must be saturated steam at a pressure of 0.85 MPa or more to provide high temperature and high humidity environmental conditions. Japanese production experience has shown that through this treatment, the linear shrinkage or expansion rate of the sheet can be reduced by nearly 50%. Second, the production cycle will be shortened by about 2/3 compared to the natural conservation method. Although this will increase equipment investment and thermal energy consumption, the improvement of product quality and comprehensive utilization can bring benefits to the production and operation of the enterprise.
6. The extension of secondary processing has perfected the complete set of production. In the past, the production of ordinary type plates was generally introduced to the market in the form of plain plates. For molded plates, if they were not subjected to secondary processing, they could not form “commodities†to the market. The secondary processing consists of cutting the large-format sheet into the required size of the building; processing the joint with the boring head and finishing the surface on the side.
In the cutting and cutting process, the benchmark for the molding of the stencil must be based on the line of the profile, and cannot be as large as the ordinary plate. This is the first issue to consider when designing and manufacturing a panel.
Shantou processing can use equipment similar to that commonly used in wood processing, but the design of the tool and spindle should take into account the particularity of processing cementitious materials.
Surface finishing is the most complex and expensive process in secondary processing. The dimensional stability of the sheet can be further improved by finishing.
At present, it is a common type of board in foreign countries. When it is used to construct a wall, it is also used for at least one to two layers of sealing primers before it is shipped from the factory. This is the reason for consideration. Furthermore, the appearance of the molded panel can be visualized by the coating, especially as the simulation requirements of the profile pattern are continuously improved, the color is developed from a single color to a multi-color, and the multi-color coating can only be completed in the factory, so that the secondary processing line becomes An integral part of the molded board production line. The finishing process generally includes processes such as preheating, coating, drying, and cooling. If multiple finishes are required, the coating and drying stations should be increased accordingly; the length of the cooling station is directly dependent on the productivity requirements. The design of the finishing process is of course also related to the type of coating chosen, which is directly related to the durability, gloss and cost of the coating. Products currently using acrylic paints in Japan must be repainted after 7-8 years, while products using fluorocarbon resin coatings can guarantee a life of more than 20 years. In general, the cost of secondary processing is equivalent to the production cost of plain board, which is why the price of molded board products is higher.
The newly developed production line is also recycling waste recycling, reducing the consideration of environmental pollution. The electrical control of the whole line is controlled by advanced PLC. Some sections such as batch weighing and mixing section are controlled by industrial computer, which greatly improves the automation level, and mainly makes the product quality stable.
Development Status of Cement Particleboard and Molding Process (2)
The E119 standard tests 120mm thick composite wall panels made of cement particleboard and mineral wool insulation, with a fire resistance limit of up to 2 hours. This means that after the flame of 1010 ° C was sprayed on the 2.7 m square test piece for 2 hours, the plate was not burned through, and the temperature on the other side of the plate was not raised to the ignition temperature of the cotton fabric. China's Sichuan Fire Research Institute also measured 80mm thick hollow composite wall panels composed of 10mm cement particleboard according to China's GB9978 standard, and its fire resistance limit was 0.75 hours. It can be seen that the cement particle board can meet the requirements of the non-load-bearing exterior wall of the fire-rated grade III and the partition wall of the building grade with the fire-rated grade according to the requirements of GBJ16-87 "Code for Fire Protection of Building Design". This is one of the reasons why the United States, Japan and other countries that used to use wood materials as building components have used cement particleboard more and more.