What is the difference between aluminum-plastic panels for curtain walls and aluminum-plastic panels for outdoor signs?

(Summary description)Aluminum-plastic composite panel is a new type of building decoration material, which has the advantages of light weight, good rigidity, smooth surface, rich and colorful colors, convenient construction, etc. It is widely used in curtain walls, indoor and outdoor decoration and advertising signs, etc. It is a reflection of modern architecture And important decorative materials of decorative style.

What is the difference between aluminum-plastic panels for curtain walls and aluminum-plastic panels for outdoor signs?

(Summary description)Aluminum-plastic composite panel is a new type of building decoration material, which has the advantages of light weight, good rigidity, smooth surface, rich and colorful colors, convenient construction, etc. It is widely used in curtain walls, indoor and outdoor decoration and advertising signs, etc. It is a reflection of modern architecture And important decorative materials of decorative style.

详情
Aluminum-plastic composite panel is a new type of building decoration material, which has the advantages of light weight, good rigidity, smooth surface, rich and colorful colors, convenient construction, etc. It is widely used in curtain walls, indoor and outdoor decoration and advertising signs, etc. It is a reflection of modern architecture And important decorative materials of decorative style.

Aluminum-plastic composite board is a kind of board composed of aluminum and plastic. Specifically, the aluminum board and the plastic core layer are bonded and compounded by a polymer bonding material under certain process conditions. It is a "sandwich" type. Structure of the plate. In actual production, the front and back aluminum plates used as panels are generally coated with decorative and protective coatings.

From the perspective of the material structure of the aluminum-plastic composite board, its service life has a decisive relationship with the selection of raw materials and production processes. The selection of raw materials and the process control of the production process are the key factors that determine the service life of the aluminum-plastic composite board, such as fluorine Coating of carbon coating, selection of LDPE material, selection of aluminum material, etc., as well as aluminum plate formation treatment, baking temperature control, composite pressure and temperature correspondence required in the production process.

  The following focuses on the analysis of the differences between aluminum-plastic panels for curtain walls and outdoor and logo aluminum-plastic panels from the perspective of the composition and process control of aluminum-plastic panels.

   1. Application of fluorocarbon resin

As we all know, fluorocarbon coatings with superior weather resistance and durability, corrosion resistance, and stick resistance are widely used in outdoor building curtain walls. The fluorocarbon resin content in fluorocarbon paint is required in aluminum-plastic panels for curtain walls. (Polyvinylidene fluoride) must be equal to or higher than 70%. Only in this way can the quality of the fluorocarbon coating and the long-lasting appearance of the building exterior be ensured. However, due to the fierce competition in the market, some coatings with low fluorine content and low price came into being. In the short term, although this type of coating is not much different from HYLAR5000 or KYNAR500 PVDF coatings in appearance, with the extension of use time, their weather resistance can not compete with HYLAR5000 and KYNAR500 PVDF coatings, and the appearance of building exteriors is maintained. Time and life will also be shortened. Therefore, when choosing a fluorocarbon coating manufacturer, it is recommended to choose a coating company with a large brand and a large output, such as PPG in the United States and Beckers in Sweden. Because they can be adequately guaranteed in terms of quality stability and process guidance.

   On the other hand, the coating process of fluorocarbon coating is the key factor to determine whether the performance of fluorocarbon coating can be guaranteed in all aspects. The processing technology of fluorocarbon coating needs to be baked at high temperature, and under certain temperature conditions, its performance in all aspects can reach its best state. If the required process temperature is not reached in the production process, the performance of all aspects will be greatly reduced, and even worse than other types of coatings, such as polyester coatings. Some production companies choose aluminum materials that do not meet the requirements for curtain walls, such as 1××× series, from the cost considerations, so that they have to reduce the baking temperature to meet the board type requirements, which greatly reduces the coating performance. After comparing and analyzing the performance of fluorocarbon panels of different manufacturers, it is found that they are also fluorocarbon curtain wall panels, but the performance of each aspect is very different. From the coating performance point of view, good fluorocarbon coatings can achieve more than 5,000 solvent wiping and T bending performance ≤ 2T, while poor fluorocarbon plates have only 1,000 solvent wiping, some less than 500, which is equivalent At the level of some polyester coatings. If the process requirements are not met, the chemical resistance of the coating, such as acid resistance and alkali resistance, is difficult to meet the requirements, and it is impossible to pass the 4000-hour weather resistance test.

  The use of aluminum-plastic plates for signage determines that it does not require high weather resistance requirements for the coating, so most of the coatings are selected from polyester and other coatings, and their performance is far lower than that of fluorocarbon coatings.

   Second, the difference of PE core material

Aluminum-plastic composite panels generally use high-pressure low-density polyethylene resin (LDPE) as the core material. Its mechanical properties, anti-aging properties, moderate toughness and bending properties have an overall performance on aluminum-plastic composite panels (especially aluminum-plastic panels for curtain walls). Has a major impact.

In the process of using aluminum-plastic composite board, it is required to have good processing properties such as hemming, bending, and slotting. Therefore, when selecting PE core material, the requirements for PE should be stable performance, moderate melt index, and fracture extension. Raw materials with better growth rate. According to the different use scope of the product, the melt index is generally required to be 0.4ˉ2.0g/10min, the aluminum-plastic panel for curtain wall is preferably 0.4ˉ0.8g/10min, and the elongation at break should be greater than 400%. Because the core material for LDPE with suitable melt index is adopted, the surface of the aluminum-plastic composite board has good strength and high flatness. Larger blocks can be used in engineering design. For example, the use of LDPE with too large melt index is not only difficult to process. The shape is fixed, and the strength of the plate after molding is also low, which is only suitable for the use of smaller blocks in engineering design. In the production process, if the LDPE with a large melt index is selected, it is easy to be excessively softened under high temperature conditions, and it cannot guarantee sufficient compound pressure. Only the method of reducing the process temperature and the use of a low-melting polymer adhesive film can be used. It will lead to a decrease in the peel strength of the bonding force between aluminum and plastic, so some products are extremely improper to lower the production temperature to ensure the flatness of the surface and sacrifice the peel strength. The experiment proves that the seasonal temperature difference of the aluminum-plastic board for curtain wall in actual use can reach -30° to more than 60°. Such a large temperature difference is easy to make the aluminum-plastic composite board gradual. If the initial peel strength is not high or the PE core material is softened If the point is too low, the application of aluminum-plastic composite panels on the curtain wall will have major quality risks.

   At present, there are a large number of recycled materials used in the production of aluminum-plastic composite panels. Most of these recycled materials have been recycled many times. The internal structure of the material is greatly damaged and the degradation between the molecules is serious. Generally, the recycled material has unstable melt index, large and small, and elongation at break is about 100%. Therefore, the processed plate has poor flatness, many small pits on the surface, and the plate is easy to break. This kind of reclaimed material can only be used for aluminum-plastic board for signage, and is not suitable for the production of aluminum-plastic board for curtain wall.

In the production process of aluminum-plastic panels for curtain walls, LDPE should be selected according to the actual situation. Considering the environmental protection and recycling of materials, high-grade recycled PE can be used, or recycled PE can be mixed with new materials. The addition amount is generally not The performance of the aluminum-plastic board for curtain wall is limited. The performance index requirements for LDPE of aluminum-plastic panels for curtain walls are generally specific gravity 0.925-0.945, melt index 0.4ˉ0.8g/10min, and elongation at break should be greater than 400%.

   3. Selection of aluminum

   Aluminum is the main base material in aluminum-plastic composite panels. From the perspective of use, the aluminum material plays a role in strengthening and supporting the aluminum-plastic composite board, and is in contact with the surrounding environment through the coating. Therefore, the choice of aluminum material has a great influence on the quality of aluminum-plastic composite panels.

  Aluminum-plastic composite board has strict requirements on the specifications, chemical composition, mechanical properties, dimensional deviation, appearance quality and other aspects of aluminum substrates. The national standard clearly requires that the thickness of the aluminum plate in the aluminum-plastic panel for curtain walls is not less than 0.5㎜, and the material properties should meet the rust-proof alloy aluminum of the 3000 series or more than 3000 series (such as 5000 series) required by GB/T3880, and should not be used. 1100 series pure aluminum.

From the perspective of the use of aluminum-plastic panels for curtain walls, the selection of aluminum materials should focus on the wind-pressure resistance and fatigue strength of aluminum-plastic composite panels. This is because the fastening bolts form a shear force with the aluminum-plastic composite panels. The bending point is a test of fatigue strength due to the wind load. Therefore, the shear strength and fatigue strength of aluminum are very critical. After comparing the performance of different grades of aluminum strip, it can be seen that the shear strength and fatigue strength of 1100 pure aluminum are not as good as 3003 alloy aluminum, so the aluminum strip used for aluminum-plastic panels for curtain walls should not be selected from 1100 pure aluminum. 3×××, 5××× alloy aluminum has anti-corrosion performance, especially 5005 alloy aluminum, which can resist the corrosion of seawater salt spray in coastal areas.

Attachment: Partial performance comparison of 3003 alloy aluminum and 1100 pure aluminum

Alloy state Tensile strength (Mpa) Specified non-proportional elongation strength (Mpa) Shear strength (Mpa) Fatigue strength (Mpa)
1100 pure aluminum H18 172 160 90 60
3003 alloy aluminum H16 190 188 105 69
5005 alloy aluminum
201 190 113 71
  
In addition, from the perspective of the production of aluminum-plastic composite panels, the aluminum material needs to be cured at high temperature during the painting process. Under this condition, the state of the aluminum material will change, and at the same time, the aluminum material will deform to varying degrees. The degree varies with the process parameters such as curing temperature and heating time. Different grades of aluminum have different degrees of deformation due to temperature. According to the actual production experience, the 1100 series of pure aluminum is much worse than the 3003 or 5005 series of aluminum alloy in the degree of high-temperature deformation and flexibility during production and processing. Therefore, when using 1100 series aluminum coating, some manufacturers have to reduce the baking temperature of the paint to meet the requirements of plate shape and yield, thereby sacrificing important coating performance.

   Fourth, the importance of backplane handling

   Most manufacturers have relatively high requirements for the apparent quality of aluminum-plastic composite panels, and many manufacturers often ignore the treatment of the backplane. Some manufacturers generally only do pre-treatment of the backplane to remove the rolling grease during aluminum processing. However, only the surface treatment of the chemical conversion film can not meet the corrosion protection requirements of the aluminum material exposed, resulting in hidden dangers during use. Therefore, high-grade aluminum-plastic composite panels (especially aluminum-plastic panels for curtain walls) should be treated with a layer of paint on the surface of the bottom plate to enhance the anti-corrosion effect of the surface.

  Five, the choice of protective film

  The surface of the aluminum-plastic composite board will be covered with a protective film. Its purpose is to protect the product from damage during a series of circulation processes such as handling, inventory, transportation, processing, and installation. In the production process of aluminum-plastic composite board, the protective film seems to be an auxiliary material, in fact, it has a great effect and is an indispensable part of the aluminum-plastic composite board product.

  For aluminum-plastic composite panel manufacturers, how to choose the right protective film and use the protective film correctly is very important to ensure the product quality and construction quality of the aluminum-plastic composite panel.

In order to better play the role of product protection, the selection of the protective film should meet certain requirements, such as having a certain adhesive force, it can be well pasted on the surface of the aluminum-plastic composite board without falling off, no pollution, no corrosion after pasting The adhered surface does not cause chemical reaction on the adhered surface, and has good weather resistance. It can be easily peeled off when torn, without leaving any residual glue, and can be drilled, cut, bent and other plastic processing after pasting.

   The selection of protective film should fully consider the characteristics of the product, consider the variety of aluminum-plastic composite board, coating material, surface smoothness and other factors. In order to prevent the plastic film for curtain wall from being irradiated by ultraviolet rays after installation, the plastic film for curtain wall should use black and white protective film with good anti-ultraviolet effect. However, in the actual process, the quality of the black and white film substrates produced by some protective film manufacturers is poor, and the black and white film still has light transmission under sunlight, which does not play the role of anti-ultraviolet rays, causing the coating to produce color difference, or under outdoor sunlight conditions. The protective film is prematurely aging, which can not be torn or broken into pieces when tearing the film, causing difficulties for the constructor. At present, there are two types of protective film for aluminum-plastic composite board: solvent type and rubber type. Rubber-type protective film is better for aluminum-plastic panels for curtain walls, because its material and performance in all aspects are significantly better than solvent-based protective films.

   VI. Use the so-called "new products" with caution

After decades of development, aluminum-plastic composite panels have achieved unprecedented development in terms of output, variety, production technology, quality control, and application fields. Various new products have also emerged continuously, which promotes the development of aluminum-plastic composite panels. It plays an active role and gives customers more choices, but there is no lack of "new products" that are rushed to market because of the temptation of certain commercial interests. The author believes that customers should be "cautious" in choosing and using curtain wall composite panels.

As an aluminum-plastic panel for curtain walls, first of all, it is necessary to meet the requirements of weather resistance. Because any new material needs to be applied on the basis of scientific tests and experiments, but also need to pass the test of time. Although the experimental conditions can now simulate the various elements of the atmospheric environment and greatly shorten the experimental time, the experimental results obtained are still quite different from the natural environment. At the same time, because of the limitation of the experimental time, they are different from the actual needs. Certain gap.

  The author has been engaged in the research of aluminum-plastic panels for more than ten years, and has tested the aluminum-plastic panels of grade A, nano-anti-fouling aluminum-plastic panels and low-oil fluorocarbon aluminum-plastic panels that have appeared on the market in recent years. It was found that the latest fire-resistant aluminum-plastic panels, including a well-known foreign brand, could not fully meet the GB8624-2006 flammability rating standards for building materials and products. As a material for outdoor use, it is necessary to significantly increase the budget and adopt a product that meets the new requirements but at the same time sacrifices some basic important indicators (such as reduced peel strength, a significant increase in the proportion of the board, etc.), which is debatable. Because the changes of these important index data will have a great impact on the original excellent mechanical properties of the plate.

  According to relevant environmental experts, aluminum-plastic composite panels are a resource-saving product with a recycling rate of almost 100%, which is worthy of promotion. However, if a large amount of inorganic materials are added to the aluminum-plastic composite panel, the value of resource recycling may be reduced, thereby causing waste to the environment. Therefore, as a public building for indoor use, appropriate products should be selected according to the design fire resistance level. Due to the structural characteristics of the aluminum-plastic composite board itself, the fire resistance performance is much higher than the wood and cloth materials commonly used for interior decoration, which is completely in line with the general Fire protection requirements for interior decoration.

Nano antifouling coating technology Except that the performance test of the nano self-cleaning coating product developed by a nano engineering technology center in Beijing basically meets the requirements (if it can reduce the application cost, it should have promotion value), other nano plates collected on the market cannot It meets the requirements described by it, and some important indicators cannot meet the standard requirements of aluminum-plastic panels for curtain walls. Some methods that use polyester paints and antifouling additives lose their function in a few months.

Therefore, for the use of aluminum-plastic panels for curtain walls in key projects, it is recommended that customers should choose mature products that have been tested for a long time. For decorative projects such as signage that are not demanding and have a long service life Board etc. can consider choosing some "new products" to use.

  In summary, there are obvious differences in the selection of materials, the control of the process, the requirements of performance indicators and the requirements of construction applications in the aluminum-plastic panels for curtain walls and the plates for signage. As an aluminum-plastic panel for curtain walls, its requirements are relatively high, and the requirements for material matching and process control are very scientific. It needs systematic consideration to ensure that all aspects of its performance reach the best state. If one aspect is too biased, other performance will be greatly reduced. Thus affecting its use function. As for the signage board, the corresponding requirements are relatively low, and the service life is not as high as the curtain wall board, as long as it can meet its functional requirements. Therefore, the author recommends that all users use aluminum-plastic composite board products according to different situations.
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