What is a PVC sheet?
pvc sheet is a kind of vacuum dimpled sheet, also known as decorative sheet or attached adhesive sheet, and has been applied to surface packaging in building materials, packaging and medical care industries.
According to the degree of softness and hardness, PVC sheets can be divided into soft PVC film and rigid PVC sheets. Soft PVC film is mainly used on floors, ceilings and leather surfaces. However, the soft PVC film contains softeners, which also makes the difference between the soft PVC film and the rigid PVC sheet, so it is easy to become brittle and difficult to keep, thus limiting its field of use. On the contrary, the rigid PVC sheet does not contain softeners, so it is easy to form, non-toxic and pollution-free, does not become brittle and has a long shelf life, which increases its development value and application.
What are the advantages of rigid PVC sheet?
With the development of environmental protection concepts, people attach more and more importance to the recycling and use of Rigid PVC Sheets. Therefore, PVC Rigid Sheet has been widely used in petroleum, chemical, construction, medical, automotive, and electronic communications industries, etc. Absorption without deformation and easy processing. For example, China transparent PVC rigid sheet air duct does not require any flange connection or silencer, has the characteristics of fire prevention and moisture proofing, and its heat insulation properties also meet to the requirements of use. In the United States, rigid PVC materials are beginning to replace PC materials used in transparent medical parts, such as Y-connector, sleeve, filter, instiller and sample container, because the resistance and transparency of rigid PVC can be comparable to PC. However, stress cracks often occur where PC meets conduit and other parts, and rigid PVC can reduce or eliminate stress cracks.
Features of PVC Rigid Sheet
PVC rigid sheet, a superior thermoforming material, can replace stainless steel and other corrosion-resistant materials. PVC has a high hardness, which increases as molecular weight increases, or decreases as temperature increases. Rigid PVC sheet has strong mechanical properties, with modulus of elasticity reaching up to 1500-3000 MPa, but the elasticity of soft PVC is only 1.5-15 MPa. However, the elongation at break of China transparent PVC rigid sheet can reach 200-450%. PVC has ordinary friction properties, with a static friction factor of 0.4 to 0.5 and a dynamic friction factor of 0.23. Due to its poor heat resistance stability, PVC begins to decompose at 140℃ and melt at 160℃. PVC has a low coefficient of linear expansion, is noncombustible, and its oxidation number can reach over 45. PVC is a polymer with good electrical properties, but due to its higher polar nature, the insulation property electrical is lower than PP and PE. It has large dielectric constant, dielectric loss angle tangent and volume resistivity, but low corona resistance, so PVC is generally suitable for low voltage and low frequency materials. China PVC rigid sheet can be resistant to most inorganic acids, alkalis, salts and organic solvents. PVC is resistant to most inorganic acids, alkalis, salts and organic solvents.
Due to its excellent corrosion resistance and certain mechanical strength, the PVC rigid sheet, after secondary treatment, can be transferred to the sulfuric acid (hydrochloric acid) tank, the empty medical needle holder, the chemical treatment support, the water tank of public toilets; processed product model, decorative plate, exhaust duct and equipment liner as well as other special-shaped products and containers. It is clear from customer feedback from Chinese PVC rigid sheet manufacturers that PVC has become the ideal material for chemical industries, building materials, decoration and other industries.
Key Points in PVC Rigid Sheet Processing Process
PVC Rigid Sheet adopts the processing process of batching and mixing. The quality of PVC mixture preparation directly affects the extrusion speed, process parameters and product quality, so this process should be strictly controlled. The main equipment for the preparation of the PVC mixture includes a mixer, a screw feeder and a hopper. The mixer is a horizontal type double cone mixer; the screw feeder is a feeder; the hopper is a storage tank.
1. For the dosing process, the materials of the components of the formula should be accurately measured to avoid large measurement errors, which may cause changes in the actual formula and increase the difficulty of analysis and control of the quality. Chinese PVC rigid sheet manufacturers often ignore this key point in the production process and should pay enough attention to it.
2. Rigid PVC sheet should be cut into appropriate sizes according to users’ actual needs. The improper size will also cause measurement errors and quality problems in the production process.
3. Rigid PVC sheet has many components, so it is essential to choose a reasonable feeding order, which should benefit the additives to work, avoid additive confrontation effect, and improve the dispersing speed.
4. China PVC rigid sheet welding process is also very important. Improper soldering will easily lead to quality problems in the products. There are many welding techniques, and the most commonly used are gas shielded arc welding and submerged arc welding.
Typical Mixing Process of Rigid PVC Sheet
1. First mix the PVC resin in the high-speed mixer and increase the temperature to 60℃.
2. Add the stabilizer and continue to increase the temperature to 90℃.
3. Add internal lubricants, processing additives, impact modifiers, fillers, colorants, etc.
4. Enter external lubricants and continue to increase the temperature to 115-120℃.
5. Discharge the materials into the rotary cold mixer with low speed coolant.