Modified PVC transverse heat shrinkable film production line
DATE：2021/7/6 8:37:11 / READ： / SOURCE：This station
Modified PVC transverse heat shrinkable film production line
Poly (vinyl chloride) (PVC) is a polymer compound polymerized from vinyl chloride monomer. Because of the presence of chlorine atoms in the main chain of the polymer, its polymer structure is different from that of PE, and it has a series of unique properties. The main physicochemical data are as follows: 1. The appearance is white powder, the relative molecular weight is 36870 ~ 93760, the relative density is 1.35 ~ 1.45g/em (varies with composition), the apparent density is 0.40 ~ 0.65g/em ', the heat capacity is 1.045 ~ 1.463j/g ℃ (0 ~ 1000), the particle diameter is 60 ~ 150pm, and the refractive index is n = 1544. 2 thermal properties: the softening point of PVC is 75 ~ 85 ℃, and the flow temperature is about 175 ℃; When the temperature is higher than 100 ℃, PVC begins to degrade and release hydrogen chloride. The higher the temperature is, the more serious the degradation is, accompanied by a series of color changes (yellow → black). 3 combustion performance: it can burn and degrade on the flame, release hydrogen chloride, carbon monoxide and benzene, but it will extinguish when it leaves the flame. Mechanical properties: UPVC is a hard and strong material, while SPVC is a soft and tough material. The tensile strength of PVC is 35 ~ 63Mpa, and the tensile modulus of UPVC is 2500 ~ 4200mpa. The tensile modulus is related to the relative molecular weight of PVC resin and the type and amount of batch. The flexural properties of PVC are related to the relative molecular weight of the resin. For example, the flexural strength and flexural modulus of the resin with K value of 69 are 86.87 MPa and 3134.36 MPa, respectively; When the K value is 72, the bending strength is 79.30mpa and the bending modulus is 2995.77mpa. The flexural strength of UPVC can reach 107 ~ 138mp when the reinforcing agent (such as chopped glass fiber) is added into PVC. The impact toughness of unperturbed UPVC is poor and the notch sensitivity is high. Electrical properties: PVC has high density, electrical breakdown resistance and aging resistance, and can be used as low-voltage cable and cable sheath below 10000v. Water absorption: the water absorption of PVC is low, and the water absorption of rigid PVC is less than 0.5% when immersed in water for a long time; The water absorption was 0.05% after soaking for 24 hours. The water absorption of soft PVC with proper plasticizer is less than 0.5%. PVC also has very low fog permeability, air permeability and vapor permeability. Aging property: under the action of light and oxygen, PVC resin gradually decomposes (aging), and the surface of PVC material acts with oxygen in the air to accelerate the degradation of high polymer by heat and ultraviolet light, which decomposes hydrogen chloride to form carbonyl group. PVC transverse heat shrinkable film production line www.handern.comPVC resin is one of the largest output varieties of synthetic materials, which is widely used in light industry, building materials, agriculture, daily life, packaging, electric power, public utilities and other departments. In developed countries, the consumption proportion of PVC is about 65% ~ 70% for building materials, 8% for packaging products, 7% for electronic appliances, 5% for furniture and decoration products, and 4% for general consumer goods. The application direction of PVC can be roughly divided into two categories: one is hard and semi-hard products, including plate, pipe, door and window, diaphragm and building materials instead of steel and wood; Second, soft products, including wire, cable, film, sheet, paving materials, artificial leather and sealing materials. PVC transverse heat shrinkable film production line www.handern.com
PVC resin obviously has good comprehensive properties and multiple uses, but there are also some defects: 1. Poor thermal stability. The melting temperature of PVC is about 210 ℃, but it begins to decompose and release hydrogen chloride at 100 ℃. When the temperature is higher than 150 ℃, it begins to decompose and release hydrogen chloride. When the temperature is higher than 150 ℃, it decomposes more rapidly. Therefore, we must first try to improve its thermal stability. 2upvc is brittle. The impact strength (notch) value of the cantilever beam at room temperature is only 2.2kj/m, and it is easy to crack under impact, so it can not be used as structural material. At low temperature, PVC products become more brittle and can not be used. The lower temperature limit of general PVC is - 15 ℃, and the lower temperature limit of soft PVC is - 30 ℃. The Vicat softening temperature of PVC hard products is usually lower than 80 ℃, and its application is limited; When the temperature is higher than 90 ℃, PVC is easy to soften, and it is easy to have viscous flow and lose shape retention ability under stress. Because of no or only a small amount of plasticizer, the apparent viscosity of rigid PVC melt is very high, the fluidity is poor and the processing is difficult. The plasticizing effect of 0pvc is not stable. Small molecule plasticizers are often used in soft PVC. They will dissolve, volatilize and migrate in the process of processing and using products, which not only pollute the environment, but also make products hard and brittle and lose use value. 6pvc molecular chain contains strong polar CC bond, which is a polar polymer. When PVC is used in the production of medical products, its hydrophilicity and biocompatibility are poor, which affects its use. PVC transverse heat shrinkable film production line www.handern.com
The purpose of PVC modification is to improve or overcome the above shortcomings or give new properties, further broaden the application scope of PVC and meet the special requirements of various products for material properties. There are various modification technologies for PVC. The purpose of some modification methods and raw cut PVC modification is to improve or overcome the above shortcomings or give new properties, further broaden the application scope of PVC and meet the special requirements of various products for material properties. There are many modification technologies for PVC, and some modification methods (such as changing polymerization methods, copolymerization modification, etc.) can only be carried out in PVC resin factories, so their application is limited. Other modification methods (such as blending, filling, etc.) are widely used because of their simple equipment and production process, which can also be carried out in ordinary plastic products factories. PVC transverse heat shrinkable film production line www.handern.com
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