What are the advantages of latex paint? How about air permeability?

label: Latex paint

What are the advantages of latex paint? Emulsion paint is a kind of water dispersible paint, which is refined by taking synthetic resin emulsion as the base material, adding various additives after the filler is ground and dispersed. What are the advantages of latex paint? How about air permeability? The first advantage of latex paint is that it is safe, non-toxic and tasteless, which completely solves the labor protection and environmental pollution problems caused by the volatilization of toxic gases of organic solvents among painters, and fundamentally eliminates the risk of fire. Advantages: convenient construction, which can be applied by brushing, roller coating, spraying, troweling, scraping, etc. Construction tools can be cleaned with water. Advantage 3: The coating dries quickly, and can be painted two or three times a day, so the construction efficiency is high and the cost is low. Advantage 4: good color retention and weather resistance. Most exterior wall latex white paint is not easy to yellowing, and the weather resistance can reach more than 10 years. Advantage 5: good air permeability, strong alkali resistance, so the coating is not easy to blister when the internal and external humidity difference is large, and the coating is not easy to "sweat" indoors, especially suitable for painting on the cement surface and plaster surface of the internal and external walls of buildings. Latex paint is widely used for interior and exterior wall decoration of buildings due to its wide variety of designs and colors, bright colors, light weight, and fast building decoration. Covering property: covering property and covering property are the components of high-quality latex paint, representing the painting work with better effect, less time consumption and less consumption. Adhesion and easy cleaning: good adhesion can avoid cracks and defects; Easy cleaning ensures gloss and color retention. Therefore, they are important reference indicators when you choose emulsion paint. Applicability: latex paint with good applicability will not cause bubbles to overflow and splash in the process of operation, and it will bring smooth walls to the room. Waterproof function: elastic emulsion paint has excellent waterproof function, preventing water from penetrating the wall and damaging the cement, thus protecting the wall, and has antibacterial function. It has good anti carbonization, antibacterial and alkali resistance.

2020-01-15 17:18:17

How about the decoration style of integrated ceiling?

label: integrated ceiling

How about the decoration style of integrated ceiling? Various integrated ceiling enterprises have entered the market. The speed of development is unimaginable, and its integrated ceiling products are gradually accepted by the world. A variety of integrated ceiling styles are coming to the market. What about the decoration style of integrated ceiling? The decoration style of integrated suspended ceiling 1. The decoration boom since the 1990s for natural leisure has brought people many decoration concepts, such as small gardens, cultural stone decorative walls and rain flower stones, and other decoration techniques have emerged in real design. Especially after the decoration phenomenon of "the whole country is decorated in yellow" caused by the large use of red beech, getting close to nature and returning to nature has become one of the goals pursued by people. 2. Openness and generosity Since the mid-1990s, the design idea of home has been greatly liberated, and people have begun to pursue a variety of design methods. A series of relatively complete design concepts, such as modernism and post-modernism, are reflected in interior design. This style basically uses cherry wood as the main wood fastener finish. 3. Soft style At the end of last century and the beginning of this century, a kind of club like design that pursues stability and luxury began to appear, and then appeared in a large number of ordinary home decoration. This style emphasizes the simple but content free decoration form, and gradually forms a style with black walnut as the main wood decoration panel. In China, minimalism and minimalism began to emerge, forming a style. 4. Elegant style This is a design style that appeared at the end of the last century and the beginning of this century. It uses wallpaper as a decorative surface material, combined with oil mixing woodworking. This style emphasizes the harmony of proportion and color. People began to use the upper part of a wall in the same color as the ceiling, while the wall used a wallpaper with a light texture. The whole style is very elegant and quiet, without a trace of impetuosity. 5. The urban style has entered the 21st century, the housing reform has been carried out, and the emergence of many young first-time buyers has injected impetus into the generation of this style. Young people have just bought a house, many of them are short of money. At this time, the real estate is basically rough housing (a style without basic decoration), which is constrained by financial resources and forced to meet the needs of decoration. It emphasizes the appearance of "decoration" through form, in which a lot of bright colors are used. 6. Fresh Style This is a kind of interior design style with the flavor of "petty bourgeoisie" derived from the influence of minimalism. Especially with the emergence of many single nobles, this petty bourgeoisie style appears in a large number of apartment decoration. There are no members such as the elderly and children in the room, so there is no need to consider many functional issues in the decoration, often emphasizing a casual and bland nature. The light white gauze with a soft cloth sofa and a pile of pillows of various colors form an indoor space full of lazy atmosphere. 7. With the emergence of many modernists, a trend of retro style has emerged in China, that is, the revival of Chinese decorative style. Chinese painting, calligraphy and painting, and Ming and Qing furniture constitute the most important elements of Chinese style design. However, the price of these reoccupied furniture is high, which has become a major obstacle for lovers. 8. Chinese nostalgia Chinese style is relatively free, decorations can be green plants, cloth art, decorative paintings, and lamps of different styles. These decorations can have a variety of styles, but the main decorations in the space are traditional decorations such as Chinese paintings, palace lanterns and purple clay pottery. These decorations are few in number, but they can play the role of finishing touch in the space. 9. European classical style European style mainly refers to Western classical style. It emphasizes to achieve elegant decoration effect with gorgeous decoration, strong color and exquisite modeling. 10. Mediterranean style Enjoy the fresh Mediterranean style of blue sea and sky with unique aesthetic characteristics. Generally, natural soft colors are selected. In combination design, attention should be paid to space collocation, making full use of space, integrating decoration and application. In combination, the combination is generous and natural, emitting ancient and noble pastoral flavor and cultural taste. 11. Southeast Asian style In Southeast Asian style decoration, materials are mostly taken directly from natural plant resources; Wood, rattan and bamboo become the first choice for interior decoration.

2020-01-15 17:13:01

How about the performance of water-based paint? What are the disadvantages?

label: Waterborne paint

How about the performance of water-based paint? With the pressure of environmental protection policies, consumers' awareness of environmental protection continues to improve; In particular, provinces and cities across the country have issued VOC emission limit standards, encouraging the use of non solvent paints, water-based paints and other environmental friendly coatings, which has brought opportunities for development. How about the performance of water-based paint? What are the disadvantages? Performance of water-based paint (1) Poor pigment dispersion. Waterborne paint belongs to polymer dispersion system, and pigment dispersion is not very good, so measures must be taken to improve it. (2) The stability of dispersed particles is poor. Dissolved molecules are stable to shear force, heat, pH, etc., while dispersed particles are unstable, so stability measures should be taken for the dispersion system. Dispersed particles will be damaged after being subjected to shear force, so it is necessary to consider avoiding the role of shear force in the process of manufacturing and transporting water-based paint. Dispersed particles are very sensitive to pH value, and acid particles will be formed when acid substances are mixed into the paint, thus causing gelation and destruction of water-based paint. In addition, dispersed particles of water-based paint will also be damaged after freezing during transportation. (3) High surface tension. The surface tension of water is large (see Table 2), so the surface tension of water-based paint is also large. Management should be strengthened during the construction process, otherwise the following defects and film defects are likely to occur during coating: a. easy sagging; b. Poor flattening; c. It is easy to produce shrinkage cavity and pinhole; d. It is not easy to stretch into the small cracks on the surface of the coated object. (4) The evaporation heat and heat capacity are high and are greatly affected by temperature and humidity. The high evaporation heat and heat capacity of water (see Table 2) slow the evaporation of water in water-based paint. 50% of the total amount of solvent in solvent based paint evaporates during spray atomization, while only 25% for water-based paint. Slow evaporation of water is easy to cause sagging during painting, and makes painting efficiency worse. Therefore, an intermediate heating zone is required to volatilize water from the water-based primer coating. Before spraying varnish, 90% of water must be removed from the water-based primer coating (to prevent boiling water from volatilizing through the varnish during final baking) to obtain the best paint film appearance, so as to prevent the water-based primer from being re dissolved by the varnish. The evaporation rate of water is closely related to the relative humidity. When the relative humidity is high, the evaporation rate of water is very low. Therefore, the relative humidity and temperature of the spray booth must be controlled within a certain range to ensure that an appropriate amount of water is volatilized during the spray atomization process, and that water and organic solvents are properly balanced in the film. This proper balance is very important, which can make the paint have proper surface tension to wet the sprayed surface (see Table 2). (5) Good conductivity. The dielectric constant of water is large (see Table 2), so the conductivity of water-based paint is good. Generally, the resistance of water-based paint is less than 0.1M Ω), while solvent based paint has a certain resistance: 0.5~20M Ω. Waterborne paint has good conductivity, and there are special requirements when electrostatic spraying is used. (6) High corrosivity. The water-based paint contains a lot of water, so it is corrosive to containers, transmission pipelines, paint booth and other parts vulnerable to moisture. Stainless steel or plastic products are required. (7) Rheological behavior. When the viscosity of fluid decreases with the increase of shear rate, it is called pseudoplastic fluid. The rheological behavior of pseudoplastic fluid is related to its rheological path, that is, it is time dependent, so it is called thixotropic fluid. Based on the characteristics of water-based paint, the viscosity value measured by flow cup does not have reproducibility, and the complete rheological curve of data points including low shear rate and high shear rate measured by rotary viscometer can give the complete characteristics of rheological behavior of water-based paint. Disadvantages of water-based paint 1. The water-based paint has high requirements on the cleanliness of the surface during construction and materials. Because of the large surface tension of water, dirt is easy to cause shrinkage of the film; 2. The dispersion stability of water-based coatings against strong mechanical forces is poor. When the flow rate in the transmission pipeline changes sharply, the dispersed particles are compressed into solid particles, causing pockmarks in the film. The conveying pipeline shall be in good shape and the pipe wall shall be free from defects. 3. Waterborne coatings are highly corrosive to coating equipment, so anti-corrosion lining or stainless steel materials are required, and the equipment cost is high. The corrosion of water-based coating on the transmission pipeline and the dissolution of metal cause the precipitation of dispersed particles and the pitting of the coating film. Stainless steel pipes are also required. 4. Baking water-based coating has strict requirements on construction environmental conditions (temperature and humidity), which increases the input of temperature and humidity regulating equipment and energy consumption. 5. The evaporation latent heat of water is large, and the baking energy consumption is large. Cathodic electrophoretic coating shall be baked at 180 ℃; However, the time for latex coating to completely dry is very long. 6. Organic cosolvent with high boiling point will produce a lot of oil smoke during baking, which will drop on the surface of the film after condensation and affect the appearance.

2020-01-13 17:38:06

What are the advantages of water-based paint? How about the effect?

label: Waterborne paint

What are the advantages of water-based paint? Waterborne paint is now the choice of many home decoration. Waterborne paint is harmless to human body, does not pollute the environment, and the paint film is plump, which is favored by many users. What are the advantages of water-based paint? How about the effect? Advantages of water-based paint: 1. Use water as solvent to save a lot of resources; Eliminate the fire hazard during construction; Reduce air pollution; Only a small amount of alcohol ether organic solvents with low toxicity are used to improve the working environment. Generally, the organic solvent of water-based coatings (accounting for coatings) is between 5% and 15%, while cathodic electrophoretic coatings have been reduced to below 1.2%, which has a significant effect on reducing pollution and saving resources. 2. Waterborne coatings can be applied directly on wet surfaces and in wet environments; Good adaptability to material surface and strong adhesion of coating. 3. Coating tools can be cleaned with water, greatly reducing the consumption of cleaning solvent and effectively reducing the damage to construction personnel. 4. The electrophoretic coating is even and flat. Good flattening performance; The inner cavity, weld, edges and corners can be coated with a certain thickness of film, which has good protection; The electrophoretic coating has the best corrosion resistance, and the salt spray resistance of thick film cathodic electrophoretic coating can be up to 1200h. How to distinguish true and false water-based paint 1. The main agent and curing agent of the real two-component water-based paint are basically odorless or only slightly odorous after opening the can; 2. The real two-component water-based paint is diluted with clean tap water. If special diluent or alcohol is needed to dilute it, it must not be; 3. The two-component water-based paint also belongs to non hazardous chemicals, while the fake two-component paint is often flammable dangerous goods; 4. Look at the environmental protection index: whether it contains benzene, heavy metals, high VOC and other toxic substances.

2020-01-13 17:37:18

What are the PE pipe connection methods? What are the regulations?

label: PE pipe

What are the PE pipe connection methods? The connection mode of PE pipe is different from that of U-PVC pipe. Generally, two methods are used: electrothermal fusion connection and hot-melt butt joint. What are the regulations for PE pipe connection? PE pipe connection mode (I) General provisions for installation 1. Before pipe connection, pipes, pipe fittings and auxiliary equipment shall be checked according to the design requirements, and appearance inspection shall be carried out at the construction site, and they can only be used if they meet the requirements. The main inspection items include pressure resistance grade, external surface quality, fit quality, material consistency, etc. 2. Corresponding special heating tools shall be used according to different interface forms, and open flame shall not be used to heat pipes and pipe fittings. 3. For pipes connected by welding, pipes and pipe fittings of the same brand and material should be used. For pipes with similar performance, they must be tested first and can be carried out only after they are qualified. 4. Pipes and pipe fittings shall be placed at the construction site for a certain period of time before connection, so as to keep the temperature of pipes and pipe fittings consistent. 5. When connecting in cold climate (below - 5 ℃) and strong wind environment, protective measures shall be taken or the connection process shall be adjusted. 6. The pipe end shall be clean during pipe connection, and the pipe orifice shall be temporarily blocked at the end of each work to prevent sundries from entering the pipe. 7. Visual inspection shall be carried out after pipe connection, and the unqualified shall be reworked immediately. （2） Electrofusion connection: firstly, the electrofusion pipe fittings are sleeved on the pipes, and then the special welding machine is used to power the electrofusion pipe fittings according to the specified parameters (time, voltage, etc.), so that the inner surface of the electrofusion pipe fittings embedded with the electric hot wire and the outer surface of the pipe insertion end are fused, and the pipes and pipe fittings are fused together after cooling. It is characterized by convenient and rapid connection, good joint quality, and little interference from external factors. However, the price of electrofusion pipe fittings is several to dozens of times that of ordinary pipe fittings (the smaller the diameter, the greater the difference), which is generally suitable for the connection of large diameter pipes. 1. Procedure (process) inspection of electrofusion socket connection - pipe cutting - cleaning the joint part - pipe fitting fitting into the pipe - correction - electrification welding - cooling (1) pipe cutting: the connecting end of the pipe should be cut vertically to ensure that there is enough hot melting area. Commonly used cutting tools include rotary cutter, saw bow, plastic pipe scissors, etc; High temperature is not allowed during cutting to avoid high temperature deformation. (2) Clean the joint and mark the insertion depth line: scrape the oxide layer on the surface of the pipe with fine sandpaper, scraper, etc., wipe the dirt on the connection surface of the pipe and pipe fittings with clean cotton cloth, and mark the insertion depth line. (3) Pipe fitting sleeve into pipe: sleeve the electrofusion pipe fitting into the pipe to the specified depth, and connect the welding machine with the pipe fitting. (4) Correction: adjust the position of pipes and pipe fittings to make them on the same axis, so as to prevent the joint welding from being unstable and the air tightness from being poor due to eccentricity. (5) Power on welding: the power on heating time and voltage shall comply with the regulations of the electric fusion welding machine and the electric fusion pipe fitting manufacturer to ensure that the best welding joint can be obtained under the best supply voltage and heating time. (6) Cooling: PE pipe joints can reach their maximum compressive strength only after they are completely cooled to normal temperature. During cooling, other external forces will make pipes and pipe fittings unable to maintain the same axis, thus affecting the welding quality. Therefore, the connected parts shall not be moved or external forces shall be applied at the joints during cooling

2020-01-13 17:32:21

How about the performance of PE pipe products? How are pipes connected?

label: PE pipe

How about the performance of PE pipe products? PE pipe is a commonly used municipal pipe, which is widely used in the drainage manufacturing field. It has the characteristics of high strength, high temperature resistance, corrosion resistance, non-toxic, abrasion resistance, etc. What about the performance of PE pipe products? How are pipes connected? The PE pipe product has good sanitary performance: no heavy metal salt stabilizer is added when processing the PE pipe, the material is non-toxic, there is no scaling layer, and there is no bacteria, which solves the secondary pollution of urban drinking water. Excellent corrosion resistance: except for a few strong oxidants, it can resist the erosion of various chemical media; No electrochemical corrosion. Long service life: Under rated temperature and pressure conditions, PE pipes can be safely used for more than 50 years. Good impact resistance: PE pipe has good toughness and high impact strength. Heavy objects directly press the pipe, which will not cause the pipe to break. Reliable connection performance: the strength of PE pipe hot-melt or electrofusion interface is higher than the pipe body, and the joint will not be disconnected due to soil movement or live load. Good construction performance: the pipeline is light, the welding process is simple, the construction is convenient, and the comprehensive cost of the project is low. Pipe connection: electrothermal fusibility: special electrothermal welding machine is used to connect straight pipes with straight pipes and straight pipes with pipe fittings. Generally, it is used for pipes below 160mm. Hot melt butt connection: special butt welding machine pipes are used for connection, generally used for pipes above 160mm. Steel plastic connection: flange, screw thread and other methods can be used for connection. Corresponding tools shall be prepared to facilitate construction and ensure construction quality. For example, rotating cutter cuts pipes; Rotating scraper -- scrape off the oxide skin on the surface of the pipe; Wall climbing scraper -- scrape off the scale on the surface of large-diameter pipes; Gas cut-off tool -- to realize gas cut-off field operation.

2020-01-13 17:31:14

What are the characteristics of pe pipe? How about environmental protection?

label: PE pipe

What are the characteristics of pe pipe? Plastic pipes are developing steadily. PE pipes, PP-R pipes and UPVC pipes all have a place, among which the strong development momentum of PE pipes is the most eye-catching. PE pipes are widely used. What are the characteristics of pe pipe? How about environmental protection? What are the characteristics of PE pipe? 1. Softness: because PE-RT is relatively soft. Therefore, no special tools are needed during construction, so the construction cost is relatively low. 2. Thermal conductivity: pipes used for floor heating need to have good thermal conductivity. PE-RT has good thermal conductivity, and its thermal conductivity is twice that of PP-R and PP-B pipes. It is very suitable for floor heating. 3. High temperature resistance: The high temperature resistance of PE-RT can reach 90 ℃, while that of PEX can only reach 65 ℃. 4. Low temperature heat shock resistance: PE-RT has good low temperature shock resistance. During winter construction, the pipes are not easy to be impacted and broken, which increases the flexibility of construction arrangement. 5. Environmental protection: PE-RT and PP-R can be recycled without polluting the environment. However, PEX can not be recycled, which will cause secondary pollution; 6. Stability of processing performance: PEX has problems such as controlling the crosslinking degree and crosslinking uniformity. The processing is complex and directly affects the pipe performance. The processing of PE-RT, PP-R is simple, and the properties of the pipes are basically determined by the raw materials, so the properties are relatively stable. PE-RT is the abbreviation of Polyethylene Raised Temperature. It is copolymerized by ethylene monomer and 1-octene monomer. It is a medium density ethylene octene copolymer specially designed for heating systems. It has a special molecular structure with narrow molecular weight distribution and octene evenly distributed on the main chain of the polymer. It retains the original health and processing properties of PE, It is also a new type of special material for pipes with enhanced high-temperature durability. The pipes produced with this raw material are mainly used in the field of hot water/heating pipes in buildings. Their durability is the same as the service life of buildings, with a minimum of 50 years. At the same time, they have good recoverability and high added value.

2020-01-13 17:30:09

How does the water purifier work?

label: Water purifier

How does the water purifier work? Water purifier, also called water purifier, is a water treatment equipment that deeply filters and purifies water according to the requirements of water use. Generally speaking, the water purifier refers to a small purifier for household use. How does the water purifier work? Working principle of water purifier Level 1: PP cotton: remove all kinds of visible objects/dust and impurities in tap water. The second and third stages: pre activated carbon: the third stage of some low distribution water purifiers is also PP cotton, and the carbon removes chlorine and organic impurities. It can also absorb the odor, color and smell produced by organic compounds in water. Level 4: ultrafiltration or reverse osmosis membrane: the membrane can remove bacteria, viruses, spores and other substances in the water. Level 5: Post activated carbon device: further improve the taste and remove odor. Most water purifiers adopt the progressive structure mode of screen blocking filtration principle, which is made of multi-stage filter elements connected in series from the beginning to the end. The filter elements are arranged in order from low to high precision, so as to realize the multi-stage filter elements to share and intercept the dirt, thus reducing the filter element blockage, manual blowdown, removal and cleaning times, and prolonging the cycle of filter element replacement.

2020-01-13 17:23:13

What are the advantages and disadvantages of wood grain brick? How about the cost performance?

label: Wood blocks

What are the advantages and disadvantages of wood grain brick? Wood grain brick is a new environmental protection building material with wood grain decorative patterns on its surface. It is divided into two categories: the original edge (it is long when fired, without cutting) and the refined edge (square brick, which is paved after cutting later). What are the advantages and disadvantages of wood grain brick? How about the cost performance? The advantages of wood grain brick 1. In terms of price, wood grain brick is much lower than wood floor, almost the same as ordinary ceramic tile, which is also the main factor in the best-selling market of wood grain brick. For ordinary families, if they want to have the effect of wood floor decoration and do not want to spend a lot of money, they will give priority to wood grain bricks. 2. From the use point of view, the wood grain brick is very wear-resistant and will not be affected by moisture. Its service life is basically the same as the service life of the house. Although it is not a real wooden floor, it is enough to achieve the decoration effect of "fake", which is one of the reasons why consumers like it. 3. We all know that the wooden floor needs periodic maintenance and regular waxing, otherwise it will be dull and very troublesome to clean. Wooden tiles are very convenient for maintenance, and can be cleaned with ordinary tiles. One of the disadvantages of wood grain brick is poor sense of foot. Because it is not a real wood floor, it does not have a good texture of wood floor, and certainly does not have the comfort of stepping on wood floor. 2. Because it is the texture of the imitation wood floor, although its pattern has been made very lifelike, it is still a ceramic tile after all. Compared with the real wood floor, it is still more rigid and less natural. 3. One of its advantages is that the wood grain tile is easy to clean, but don't forget that it is difficult to repair. If a small part of the damage needs to be replaced, it will affect other tile areas. However, when the wood floor is damaged, only one piece needs to be replaced. How about the cost performance of wood grain brick? The wood grain brick is still very cost-effective, its price is also relatively low, it is very wear-resistant, it is also easy to maintain, and it is more economical. But when you buy wood grain bricks, you must buy brand wood grain bricks, so that the effect will be better.

2020-01-07 17:55:41

Are marble tiles expensive? What are the advantages?

label: marble tile

Are marble tiles expensive? The texture of each marble tile is unique, especially the combination of these patterns with different colors and sizes is very fashionable, which is why many owners choose to use marble tiles for decoration. Is marble tile expensive? What are the advantages? Are marble tiles expensive? Marble tile stone includes cultural stone, marble, granite, etc. Cultural stone also includes natural cultural stone and artificial cultural stone. The prices of various stones vary greatly due to their different colors, manufacturing processes and textures. Marble price culture stone has various shapes and different colors, and is mostly used for indoor partial decoration, such as the decoration of indoor TV wall, the convex shape around the iron heating hood, or the ground treatment in the courtyard. The decoration effect is close to nature, reflecting the simple and unsophisticated decoration style. The artificial cultural stone is made of natural cultural stone through reprocessing. It is lighter, non-toxic, mildew free, and easy to install. It is suitable for local wall treatment to reduce the load-bearing capacity of the wall. The price is also more expensive than the natural cultural stone. The price of brands produced by joint ventures is generally more than 300 yuan/box. If they are imported brands, the price will be higher, It can reach about 1000 yuan/box. The price of natural cultural stone is much cheaper, generally around 120 yuan to 130 yuan/square meter. Consumers can make targeted purchases according to their economic capacity and needs. Advantages of marble tiles: 1. Beautiful and generous. Maybe the first thing that attracts you is the beautiful shape of marble floor tiles. Few building materials are as beautiful as marble. There are dozens of different varieties of marble. The choice of color ranges from black to pink to white, and even dark green with white texture (this is the most expensive kind of marble). Marble can complement many different decorative styles, from classical to ultra modern. 2. Strength improvement: after marble is compounded with ceramic tile, granite, aluminum honeycomb board, its bending, bending and shear strength is significantly improved, greatly reducing the damage rate during transportation, installation and use. 3. Long life, marble's life is beyond imagination, and it has durability. Marble is one of the oldest building materials, especially favored by Greeks and Romans. Their special marble works still exist today. If the marble is correctly installed in a suitable area, for example, in a floor that is not often used, you may not need to replace the marble in your life. 4. Improvement of anti pollution ability: During the installation or later use of ordinary marble raw boards (full body boards), if cement is used for wet pasting, it is very likely that six months or one year later, various discolorations and stains will appear on the marble surface, which is very difficult to remove. Because the bottom plate of the composite board is harder and denser, and there is also a thin adhesive layer, this situation can be avoided.

2020-01-07 17:51:29