PVC wood plastic foam building template raw material formula and operation precautionsPVC wood plastic foam building template raw material formula and operation precautions
PVC wood-plastic foamed building template raw material formula and operation precautions (at present, only the production equipment and process of this production specialize in PVC wood-plastic building template using the most detailed formula technology in the construction site, understand what template is used on the construction site, No deformation, no cracking, constant corners, no knocking, no bulkiness) PVC wood-plastic foamed building template and decorative board advertising board technology: a brief discussion on the composition and performance of PVC foamed raw materials. PVC resin plus filler (wood powder, calcium carbonate), lubricant, stabilizer, foaming agent, foaming regulator, toner and other related additives (plasticizer, toughening agent, coupling agent).
1. Resin is mainly dominated by PVC seven-type resin in China, and can also be produced in proportion with seven-type and five-type resins. Seven-type resin has a small molecular weight and good fluidity for foaming.
2. Filled with wood powder (usually (50-80) (100-120) mesh wood powder and more poplar powder), calcium carbonate is more light calcium carbonate (325-800) (1000 -1200) Around). 3. Lubricants generally use stearic acid, paraffin wax, PE wax, calcium stearate, etc. in combination with the required ratio to form a lubricant system for ecological wood production. Stearic acid and paraffin are cheap and have good lubricating properties. The disadvantage is that the melting point is too low (more than 50 degrees). Low-melting point lubricants can impart lubricity and also have plasticizing properties, so that the rigidity of the product is not very good. Vicat of the product reduces the thermal deformation of the product. If the PE wax is produced with new PE materials and the pure melting point can reach more than 80 degrees, it will not reduce the Vicat of the product. If the PE wax manufacturer uses recycled PE materials to reduce costs and add a certain proportion of stearic acid and paraffin wax, this is not a real PE wax and will also affect the performance of the product.
4. Stabilizers: The stabilizers used in PVC production include composite lead salt stabilizers, organic tin, calcium zinc stabilizers, etc. The domestic stabilizers generally used for ecological wood are composite lead salt stabilizers, and its advantage is that the price is cheap , Good thermal stability. The disadvantage is toxic and not environmentally friendly. However, the proportion of good lubricants for compound lead salt stabilizers may be around 20%, and the difference may be around 50%. If the lubricants added are all low melting point lubricants, it will also affect the performance of the product. .
5. The foaming agent is generally used in combination with AC foaming agent and baking soda, and also with AC foaming agent and sodium bicarbonate salt. AC foaming agent has the advantages of large gas generation and small dosage. The disadvantage is that a small part will remain in the product if it is not completely decomposed. This will affect the appearance of the product during the use of the product. If the residual foaming agent migrates to the surface of the product The weathering properties of products that produce spots and shadows accelerate the aging of products.
6. Foaming regulators include acrylics and methyl esters. Acrylics have lower molecular weight and viscosity and lower foaming effect than methyl esters, but the products produced are more rigid than methyl esters. The high molecular weight and viscosity of methyl esters are beneficial to foaming, but the products produced are less rigid than acrylic ones. Therefore, the acrylic foaming regulator is suitable for vacuum-shaped foaming products such as profiles and the methyl ester foaming regulator is suitable for free-foaming products such as foamed sheets.
7. The toner suitable for ecological wood is generally yellow, red and black. The yellow and red toners are inorganic and organic. The advantage of inorganic toner is that it is superior to organic toner in weather resistance, migration resistance and high temperature resistance. The disadvantage is that the amount of addition is large, and it is not suitable for brighter colors, but the price is cheap. Organic toner is the opposite. Ecological wood is generally used with organic and inorganic toners. There are two types of R titanium and anatase. R titanium has better hiding power and weather resistance than anatase, so eco-wood generally uses R titanium.
8. DOP and epoxy soybean oil are commonly used for PVC eco-wood plasticizer. DOP can reduce the force between resin molecules and improve fluidity, and has a certain lubricity to facilitate production and processing. But it can reduce the product's Vicat, one kilogram of DOP can reduce Vicat by 3 degrees. The plasticizing effect of soybean oil is not as good as DOP and has a certain thermal stability, which will also reduce the Vicat of the product.
9. Toughening agent CPE or the same type of toughening agent can improve the toughness of the product, but it will absorb part of the external slip agent during the production process, so the amount of external slip agent should be increased accordingly. However, the toughening of PVC by CPE comes at the cost of a substantial loss of material strength, rigidity and modulus. CPE will cause the thermal stability and light stability of the material to decrease, and the weather resistance will deteriorate. About the technology of PVC ecological wood green and wood (2) Second, the production process of foaming PVC resin plus wood powder, calcium carbonate, lubricant and The other additives above are mixed by a high-speed mixer to 108-123 and then cold-mixed to about 45-50 degrees: 1. Directly use cone double to produce the desired foam product. This is the so-called one-step method. The advantage of one-step production is that it does not need granulation, which saves the investment of granulation equipment and the consumption of water, electricity, labor and materials, and the maintenance cost of equipment. But the quality and appearance of the products are not as good as the two-part method. Especially the decoration is imitation multi-layer board (column column board). For indoor and outdoor decoration, it needs to have the same wood grain as the wood. The one-step method is difficult (not to say that the one-step method cannot produce wood grain such as density of 1.0 or 1.2 or more It can produce wood grain, but the density of ecological wood is generally around 0.8). 2. The cooled powder is granulated with a twin-screw and extruded with a single screw to produce the so-called two-part method. The advantages and disadvantages are the opposite. Generally, the two-part method is not used for the production of foamed boards (except for the ecological wood of door panels). Third, the deficiencies in the domestic foam board products at this stage 1, product discoloration and deformation problems A, discoloration problems (poor weather resistance). There are many reasons for its discoloration: ultraviolet rays in sunlight, high temperature, oxygen, air and the pH of the environment in which the product is located. How to prevent product discoloration can be started from the following aspects: a. Choose materials and additives with as little discoloration or good weather resistance as possible, such as toner color fastness, migration resistance, high temperature resistance, and heat resistance. Good toner. b. Add some antioxidants and ultraviolet absorbers to improve the weather resistance of the products. c. If the production and processing requirements are met, reduce the processing temperature as much as possible. d. Spray weathering paint with good weather resistance on the front of the product. e, co-extrude a thin layer of material with good weather resistance on the front of the product. B. Deformation problem (product bending and shortening or lengthening) The deformation is mainly due to the poor thermal deformation of the Vicat product. To improve the thermal deformation of the wood-plastic building template, the following aspects should be used: a, as little or as little as possible. Materials such as low-melting point lubricants, CPE, DOP, epoxy soybean oil, etc. that deform the WPC building template. b, reasonable lubrication system and dosage. c, reasonable production process such as production speed, cooling water temperature. d. How to reduce and release the internal stress of ecological wood products.
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