It is also used for medical and industrial applications including automotive sealants and interior trim, cable sheathing and flooring. It offers good solubility, electrical insulation and thermo plasticity.
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Molecular Weight
PVC k57 is a low molecular weight, general purpose vinyl suspension resin that offers excellent clarity, color and thermal stability. It is used to produce a range of plastic products including water pipes, chemical pipe, windows and doors, packing film, sanitary fittings and leatheroid. It can also be mixed with a variety of additives such as plasticisers, UV stabilisers, fillers, pigments and impact modifiers.
PVC k 57 is widely used for water pipes, chemical pipes, packing film, plastic windows and doors, carpets, sanitary fittings and leatheroid, and more. It is an excellent choice for a wide variety of applications due to its good chemical resistance, corrosion resistance and water resistance.
The Molecular Weight of the PVC is a crucial factor in the performance of the product, as it determines its processing characteristics and end-use properties such as hardness, strength and rigidity. It also impacts the overall cost of the finished product.
This is why it is essential to use a high-quality PVC. In order to do this, it is necessary to select the right resin and then add the right additives.
Westlake manufactures a large range of PVC resins with molecular weights ranging from 0.68 IV to 0.92 IV in the U.S. and Europe. They can be formulated to suit a range of application requirements and are particularly well-suited for pipes, siding and trim, electrical and automotive sealants, flooring, medical applications and technical coatings.
We also offer a range of specialty resins that are especially designed for demanding applications such as battery separators and blending. All our products are manufactured to the highest standards and comply with all BSI specifications.
These include a range of secondary protective colloids, which are used to prevent the polymer from being exposed to water during the suspension polymerisation process. These are commonly based on partially hydrolysed PVA and to a lesser extent on surfactant technology.
However, a number of important factors have been identified which limit the use of these standard colloids. Firstly, the degree of hydrolysis during the suspension polymerisation process must be controlled to avoid an unacceptable deterioration in the morphology of the PVC. Secondly, the initial colour of the polymer must be ensured not to degrade with time.
Physical Properties
PVC k57 is a polymer resin that contains chlorine atoms in its molecular structure. This makes it a highly durable material that is resistant to oxidation and has a long service life.
The physical properties of PVC k57 are determined by its chemical composition, the type of molecular structure and the additives that are mixed in. These additives can include plasticisers, stabilisers, fillers, pigments and impact modifiers.
When a continuous load is applied to a material, its stress and strain responses are complex. They involve a rapid elastic response that is fully recovered as soon as the load is removed and a slow deformation that continues until rupture occurs. The rate of this deformation is influenced by both the temperature and the time that the load is applied.
For this reason, it is important to use a material with a low creep rate and a high recovery factor when designing for the expected loading. This is especially important in the design of long-term transverse loads where failure can occur at a very early stage.
It is also important to select a material that has high strength at low temperatures. Most thermoplastics become weaker as the temperature increases, so design stresses should be calculated accordingly.
Thermoplastics are not only more ductile and resistant to chemicals at lower temperatures than metals, but they also have better resistance to abrasion and friction. This is why plastics are often used in places that are subject to frequent abrasion, such as in the transportation of goods or in heavy equipment.
Although some plastics (including PVC) experience a small dimensional change when exposed to heat, this change is very minor and is not a problem in the long term unless the pipe is exposed to excessive heat. This is because most long chain plastics have a memory property that causes them to return to their original shape.
PVC is a good candidate for use in corrosive environments as it is resistant to most zhongtai chemical. This is because of the polar chlorine atoms in its molecular formula that are bound to each carbon chain. This means that the chlorine atoms cannot escape from the compound and this allows it to withstand chemicals, particularly those that are acidic or alkaline.
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Chemical Properties
PVC is one of the most popular plastics and has a wide range of uses in building, transport, packaging, electrical/electronic and healthcare applications. It is a chemically resistant material that can be used in contact with acids, salts, bases, fats and alcohols. It is also very strong and durable, making it an excellent choice for a wide variety of applications.
PVC can be polymerised to produce a wide variety of grades, including rigid, flexible, and heat-stabilised materials. It is also a versatile raw material that can be compounded with varying proportions of stabilisers, lubricants, fillers, pigments, plasticisers and processing aids to achieve different properties for a wide range of applications.
As a thermoplastic, PVC has a complex stress/strain response that is influenced by time and temperature. This response can result in a rapid, elastic deformation or a slow, gradual, dimensional recovery. It is the combination of these two responses which is referred to as the modulus of PVC, and it must be considered in the context of the duration and rate of loading at a specific temperature.
The modulus can be expressed in a curve which represents the strain versus time at a constant stress level, e.g., at 20degC, when the material is subjected to a static load of 52 MPa. This curve is a good guide to the behaviour of PVC, but it does not account for all the effects that may occur during use.
A very useful way of assessing the internal structural homogeneity of PVC is to examine it under a VCM atmosphere at 70degC. This method can be carried out on the raw material itself or on processed and finished products, and can provide important information about the extent of residual monomer concentrations.
This test can be conducted in an autoclave or on a laboratory scale using a Beckman Coulter LS230 instrument, and can be performed in accordance with ISO 13320-1 (1999). The results will indicate the relative size of the particles.
The porosity of the PVC is a critical property, as it is a measure of how efficiently VCM can be removed from the particles at lower temperatures. This property is particularly important in medical PVC-based foils, where residual monomer levels should be below 1 ppm, and it can help to avoid thermal degradation of the resin at higher temperatures. The high porosity of the particles also helps to ensure that processing additives can be introduced into the polymer.
Applications
PVC is a versatile material that has been used for a wide range of products and applications for over half a century. Its strength, lightweight and durable properties make it a preferred choice for construction. It is often used in window frames, drainage pipe, water service pipes, medical devices, blood storage bags, cable and wire insulation, resilient flooring, roofing membranes, stationary, automotive interiors and seat coverings, fashion and footwear, packaging, cling film, credit cards, vinyl records and synthetic leather.
It is a flexible material with excellent electrical insulation and flame retardant properties. It can be moulded into a range of shapes, sizes and colours. It is also a very environmentally friendly material that has the ability to be recycled with a high rate of recovery.
Generally speaking, there are three main types of PVC. Suspension grade, Plasticised grade and Rigid PVC grades. Each type is produced in different ways and utilises a different mix of additives to achieve its desired physical properties.
The most common and widespread type of PVC is Suspension grade which is manufactured by polymerising droplets of Vinyl Chloride monomer suspended in water using a Polymerisation Catalyst. The slurry is centrifuged and the resin cake is gently dried to prevent degradation by heat. These resins are most commonly used for low volume UPVC (Unplasticised) or Rigid PVC applications such as PVC pipe, Windows, Sidings, Ducting etc.
Plasticised grade PVC is manufactured by extruding PVC with a varying proportion of appropriate stabilisers, lubricants, fillers, pigments, plasticisers and processing aids to produce a variety of finished products. These customised compounds are tailored to obtain specific groups of properties such as weather fastness, weather resistance, clarity and whether or not the product will be flexible.
There are various grades of Plasticisers, ranging from Phthalates which are not fire resistant, to Activated Calcium Carbonate, Stearic Acid/Castile Stearate and other mineral fillers. In some cases, calcium carbonate is combined with stearic acid to improve gloss and reduce Oil absorption.
Some of the Plasticisers are based on inorganic pigments which tend to be cheaper and less toxic. However, some inorganic pigments can decompose very quickly if exposed to heat or light and therefore must be used with care.
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