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What happens in Foamed Polyvinyl Chloride?-1
2022 / 02 / 18
Foamed or Microcellular Polyvinyl Chloride (M-PVC) is formed by a process called nucleation. Homogenous microcellular foams, with an average cell size of the order of 10 microns, can be produced in PVC by the process of nucleation. In this process, gas is dissolved under high pressure into the liquefied U-PVC as it's undergoing the extrusion process. This causes the uniform creation of billions of tiny bubbles that later form cells of densities ranging from l07 to l09 cells/cc. Carbon dioxide is used as the nucleating gas. A majority of the cell growth was found to occur in the early stages of foaming. The bubble nucleation density has an Arrhenius-type dependence on temperature. Additionally, in contrast to microcellular foams, structural PVC foams are typically characterized by a large variation in foam density across the foam thickness. Also, nucleation can occur at temperatures significantly below the original glass transition temperature, and that a microcellular structure can be achieved within the range of foaming temperatures. The nucleation density increases with increasing foaming temperature, but the average cell diameter remains fairly constant over the range of foaming temperatures. The small cell size and high cell density in microcellular foams provide the possibility to foam thin-wall parts in the 0.5 to 2 mm range. Some of the cellular structure of extruded PVC foam is produced by the exothermic thermal decomposition of chemical foaming agent (CFA). Azobisformamide (ABFA) is the most popular CFA for PVC. Its decomposition is dependent on PVC formulation components and mainly the thermal stabilizers which are acting as kickers. For the prediction of the processibility of a foamed rigid PVC compound, the temperature of decomposition (Td) of the ABFA must be adjusted within the range of PVC processing temperature. Ideally, the ABFA will not produce any gas until after the PVC has fused and can form a melt se
What happens in Foamed Polyvinyl Chloride?-2
2022 / 02 / 18
Organotin stabilizers are usually used for rigid foam boards. The majority of tin stabilizers used are tin mercaptides. They are cheaper than tin carboxylates and give excellent heat stability but poor weatherability. Also, they don`t act as kickers for ADC decomposition. Hence, formulations based on tin mercaptide, which are used for the majority of non-weathering foam sheet products, require kickers for ADC decomposition otherwise a low gas yield will result. Whereas, tin carboxylates are more expensive than tin mercaptides but offer excellent weathering properties and work as kickers for ADC decomposition. These stabilizers are a good choice for free-foam sheets for outdoor applications Endothermic CFAs are chemicals that take heat away from the chemical reaction. They are based on inorganic chemicals and generate CO2 gas. Sodium bicarbonate (SBC) is one of them. This produces foams with a much smaller cell structure, resulting in improved appearance and better physical properties. SBC decomposes to give CO2, H2O and Na2CO3. The reaction is endothermic and reversible and takes place over a wide temperature range, which includes the processing window of rigid PVC foam. The gas yield is only 125 cc/gm and compared with ADC the decomposition is slow and erratic, and a coarse cell structure is obtained. However, the advantages of SBC are that it is easier to handle than ADC (which is classed as an irritant), it produces a whiter foam and is less prone to give problems with cell collapse. Endothermic chemical foaming agents contain no hazardous materials so they are environmentally friendly, safe to process and grades are available for applications where contact with food occurs. The best blowing agent to use for rigid foam profile is a mixture consisting of mainly SBC (90%) with a small amount of ADC. Combining SBC with ADC ensures a reasonably fine cell structure but avoids the problem of cell collapse. To
What happens in Foamed Polyvinyl Chloride?-3
2022 / 02 / 18
Although, it is an internal lubricant only that promotes plasticization, improves polymer fluidity and the surface finish of products. External lubricant like PE wax is used to reduce the friction between the polymer and the surface of the machine to prevent it from adhering to the mechanical surface. High melt OPE waxes, provide good lubrication in middle and late processing. Lubricants should follow the principle of lubrication in the early, middle and final stages so that all materials can be protected at all stages, and the product must be stable for a long time without scaling. Internal and external lubrication systems are usually composed of PE and OPE waxes are used. To obtain a uniform cell structure, the gas is either injected or evolved by heat and must be thoroughly dispersed in the polymer melt. Some of the essential factors on which the cell structure is depended are: -Speed and pressure of the gas -Dispersive properties of the machine -Decomposition rate of foaming agent -The melt viscosity of the PVC resin Most foam profile is extruded using the celluka method also known as the inward foaming process. In this method the calibration unit is situated adjacent to the die and has the same dimensions as the die, thus controlling foam expansion. This setup gives very rapid cooling. Bubble formation is quenched in the surface of the product and solid outer skin is produced, usually about 0.5 mm thick, and a lower density core. The outer surfaces of celluka products are the same as those of solid extrusions. This structure gives the material higher mechanical strength and lowers thermal conductivity. Thus, the two major differences between U-PVC and foamed PVC is that foamed PVC is much stronger and offers much better insulation (higher V.R. value) due to its cellular structure. Foamed PVC is usually used for construction, furniture, signboard
Chlorinated Polyethylene (CPE) Characteristics and Application
2022 / 02 / 12
Chlorinated polyethylene (CPE) is a material obtained through the substitution of hydrogen atoms with chlorine atoms in high-density polyethylene (HDPE). CPE exists as a white powder. It is non-toxic and tasteless. The high-temperature thermal aging resistance of CPE fabricated from low-pressure polyethylene HDPE is superior to that of CPE fabricated from high-pressure polyethylene. CPE is commonly produced in the density range of 0.93–0.96 g/cm3 with an average molecular weight of 5–25 million and the melt index of 0.01–2.0 g/10 min. The degree of chlorination has a significant effect on the properties of CPE. For example, CPE is plastic when its chlorine content is less than 15%, a thermoplastic elastomer when its chlorine content is 16%–24%, and a rubber-like elastomer when its chlorine content is 25%–48%. It is a leather-like semi-elastic hard polymer when its chlorine content is 49%–58% and becomes a brittle resin when its chlorine content increases to 73%. Crystallinity is eliminated from high-pressure polyethylene upon the introduction of approximately 27% chlorine content. Crystallinity is also eliminated when 30% chlorine content is introduced into high-crystallinity low-pressure polyethylene. CPE rubber elastomer preferably contains 30%–40% chlorine. CPE rubber contains 25%–45% chlorine. Increasing chlorine content improves the oil resistance, air permeability, and flame retardancy of the CPE product. By contrast, decreasing chlorine content improves the cold resistance, resilience, and compression bending performance of the CPE product. Characteristics of CPE 1) CPE is a saturated rubber with excellent chemical properties, such as resistance to thermal oxygen aging, ozone aging, and acid and alkali resistance. 2) CPE has excellent oil resistance, such as resistance to ASTM 1 oil and ASTM 2 oil. Its oil resistance is comparable to t
CPE VS ALL ACRYLIC IMPACT MODIFIERS FOR C-PVC PIPES
2022 / 02 / 12
Introduction: C-PVC is manufactured by chlorinating PVC and shares some of the properties of PVC. Impact modifiers are added to PVC and C-PVC to improve impact strength; especially at lower temperatures. For U-PVC pipes in India, if fusion is optimized, addition of impact modifiers is not necessary for pipes not exposed to severe weather conditions. However, for profiles having sharp corners and window profiles exposed to solar radiation, impact modifier is necessary. On the other hand, as seen in the graph, lower elongation at break for C-PVC compound leads to lower impact strength. Impact strength of C- PVC is 30% lower than PVC. Besides, due to more chlorine content it is prone to more thermal and oxidative degradation, leading to UV degradation and in turn loss of impact strength. Hence impact modifiers as well as antioxidants in adequate quantities are essential for C- PVC pipes. Many processors prefer MBS and CPE or their combination as impact modifiers in C-PVC pipes, instead of All Acrylic Impact Modifiers (AAM), probably due to easy processability and lower cost. However, requirement of impact modifiers depend upon end use. Impact modifiers are used for long term use of PVC/C-PVC products especially under cold conditions and outdoor exposure. C-PVC pipes used for conveying hot water from solar heaters or geysers are usually exposed to solar radiation and weathering. Therefore, impact modifiers shall be judiciously selected for C-PVC pipes for indoor and outdoor use. Type of impact modifiers: Impact modifiers are elastomeric materials that are partially compatible with PVC/ C-PVC. Two basic morphologies (structures) are possible for impact modified U-PVC/C-PVC matrix. 1. The particulate structure, and 2. The network structure. Hence, two classes of impact modifiers exist accor
Replacement of lead based stabilizers with lead free stabilizers-1
2022 / 02 / 12
Nathaniel Branden, a famous Canadian-American psychologist once said, [The first step toward change is awareness. The second step is acceptance." Lead based stabilizers are being used from the very beginning to stabilize rigid PVC across the world. The decomposition temperature of PVC is much lower than its processing temperature. Thus, the processing of PVC requires heat stabilizers that do not allow HCl molecules to leave the polymer chain and increases the decomposition temperature. Lead based heat stabilizers provide excellent heat and light stability. They also provide good mechanical and electrical properties and display a very wide processing range. They are the best kind of stabilizers in terms of cost to performance ratio. Apart from these benefits, lead based heat stabilizers have a major drawback of toxicity. A small amount of lead leaching can also cause potential health problems in a young infant. The concern of toxicity has brought an initiative to phase out lead from PVC manufacturing. Lead stabilizers are being replaced by non-toxic calcium (Ca) and zinc (Zn) based stabilizers. The PVC market is now diverted towards heavy metal free stabilizers based on a mixture of Ca-Zn soap and other organic and inorganic compounds. Similar to lead stabilizers, these are also available in One Pack Systems in powder, flake and paste forms. Other than being harmless, Ca-Zn stabilizers provide good aesthetic and electrical properties. They improve color stability during the processing of PVC and provide excellent outdoor weathering performance in comparison to lead based stabilizers. A well-adjusted system of stabilizers, co-stabilizers and lubricants improves heat stability, color hold and surface gloss. They do not discolor the product after coming in contact with sulfur, whereas sulfur blackening is a very common issue in lead stabilizers. The Ca-Zn stabilizers show
Replacement of lead based stabilizers with lead free stabilizers-2
2022 / 02 / 12
Besides Ca-Zn stabilizers, Organotin mercaptide based stabilizers are another choice. These are generally available in liquid form, but nowadays powder form is also available with some manufacturers. Organotin stabilizers are very popular for transparent applications and rigid applications in America. They offer outstanding color retention in plasticized and rigid PVC processing. While selecting lubricants with tin stabilizer, stearic acid shall be avoided as it may form highly incompatible alkyl tin stearates and cause spewing in plasticized applications or exudation. Organotin stabilizers offer excellent thermal performance and therefore, are employed as the most efficient thermal stabilizers. They are more expensive than Leads, but as they are so efficient, processers with top-of-the-line extruders are reported to have come down to 0.3-0.5 PHR with the powerful methyl tins and being competitive to lead stabilizer systems. Organotin stabilizers are classified as toxic and a few are also classified as toxic for reproduction. Therefore, sufficient precautions have to be taken to avoid ingestion, skin absorption and inhalation. In the case of potable water pipe, tin stabilizers are approved in all Asian, European countries and the USA. However, in Europe, their usage in water pipe has been largely confined to France and Belgium, while it is the dominant stabilizer type used for this application in the USA. Following a risk assessment, risk reduction measures are currently under discussion at the EU level. The industry has already phased out organotin stabilizers in most of the applications. The other very new and emerging category of heat stabilizers is Organic stabilizers. They are being developed as effective, safer and more eco-friendly additives for PVC processing. The major component acting as primary stabilizer and lubricant is Calcium Stearate. Other than calcium stearate organic stab
Replacement of lead based stabilizers with lead free stabilizers-3
2022 / 02 / 12
Until 2016, 80% of the world's manufacturers were using lead stabilizers, the remaining 20% are used to stabilize PVC food packing, mineral water bottles and pharmaceutical containers. Despite many advantages, the toxicity of lead has brought a restriction to the use of lead based stabilizers in PVC articles. This restriction brought a revolutionary change in PVC processing. In 2020, 50% of the world's manufacturers are using Ca-Zn stabilizers. In Europe, Ca-Zn stabilizers already hold a larger market share than lead stabilizers. In the USA too, some large processors voluntarily switched from Lead to Ca-Zn stabilizers and brought a change in the industry. At the moment, the PVC pipes and fittings sector is seeing the development of Ca-Zn stabilizers with additional lubricants to achieve the perfect balance for pipes. Fine adjustments in composition can be made to serve a variety of applications. The Ca-Zn stabilizer systems for PVC wires and cables have gained importance during the last few years and their demand is still growing. Today, the different heat stabilizers for wires and cables compete with each other in terms of cost, performance, and processing properties. Whereas, in the profile sector, lead stabilizers are still widely used because of their good processability, the favorable cost to performance ratio, and outstanding heat stability. But, soon they will also be replaced by Ca-Zn stabilizers. The use of lead stabilizers faces restrictions from various sides. While, the Ca-Zn stabilizers are made such that they meet the requirements of the latest environmental protection standards (such as EU ROHS, REACH directive, etc). To meet future challenges more effectively, a closer collaboration between stabilizer producers and processors is necessary. As the manufacturer of PVC stabilizers, NOVISTA has a specialized technical services te
The mechanism of flame retardants
2022 / 02 / 12
Flame retardants are functional additives that endow flammable polymers with flame retardancy. They are mainly designed for the flame retardant of polymer materials. They exert their flame retardant effects through several mechanisms, such as heat absorption, coverage, inhibition of chain reactions, and incombustibility. Gas asphyxiation, etc. Most flame retardants work together to achieve the purpose of flame retardant through several mechanisms. 1. Endothermic effect The heat released by any combustion in a short time is limited. If part of the heat released by the fire source can be absorbed in a short time, the flame temperature will decrease, radiate to the combustion surface and act on the gas that has been vaporized. The heat required for the decomposition of combustible molecules into free radicals will be reduced, and the combustion reaction will be inhibited to a certain extent. Under high temperature conditions, the flame retardant undergoes a strong endothermic reaction, absorbs part of the heat released by combustion, reduces the temperature of the surface of the combustible material, effectively inhibits the generation of combustible gases, and prevents the spread of combustion. The flame retardant mechanism of Al(OH)3 flame retardant is to improve its flame retardant performance by increasing the heat capacity of the polymer, so that it absorbs more heat before reaching the ther
Electrical and Electronic Equipment: Types of Flame Retardants Used in EEE Applications
2022 / 02 / 12
Flame retardants are an important component in reducing the devastating impact of fires on people, property and the environment. Their areas of application in electrical and electronic equipment (EEE) vary depending on the materials being used, the function of the product, and the level of fire resistance that must be achieved based on fire safety standards. Flame retardants have unique characteristics, and, as a result, need to be matched appropriately to the materials used. In wires and cables, for example, the flame retardants used must meet fire safety requirements developed specifically for these products because they have the potential for spreading a fire to the electrical socket, and to walls and curtains. The level of flame retardancy required for printed wiring boards used in consumer mobile phones is different than that of wiring boards used in computer servers or in telecommunications or aerospace applications. Higher electrical and mechanical performance demands must be met with flame retardants that can achieve higher flammability and fire resistance standards, without affecting a product`s performance specifications. When it comes to fire safety, one size does not fit all. Specific flame retardants must be selected carefully to meet fire safety standards, electrical and mechanical requirements. The following classes of flame retardants used in EEE include: · Bromine-based
Flame retardants in transportation industry
2022 / 02 / 12
The world is a much smaller place today thanks to modern modes of transportation. Decisions about vacation destinations or business travel now go beyond cities and states and encompass countries around the world. Travel, whether by car, train or airplane, is faster, safer, more affordable and much more comfortable than ever before. These improvements are largely due to the technologically advanced materials developed over the last several decades. Many metal transportation components of old, for example, have been replaced with those made with plastic, making transport lighter and more fuel efficient. A variety of plastics materials (e.g., flexible plastics, foam), composite materials, new types of textiles and electronic components have given transportation engineers and manufacturers a wealth of options when it comes to transportation design, function and performance. These materials, however, which are now used in transportation products and components such as structural parts, electrical cables and wires, carpets and upholstery, must also meet flammability standards and requirements. Often, flame retardants are incorporated into these materials to help meet these standards. Notably, the right flame retardant solution must be matched to the specific material
Application of flame retardant in textile industry
2022 / 01 / 22
As an indispensable part of the national economy and people's livelihood, textiles are divided into three categories according to their uses: clothing textiles, decorative textiles and industrial textiles. They occupy an important position in people's daily life. However, textiles are relatively easy to burn due to their constituent raw materials. In recent years, there have been many reports of fires caused by improper storage of textiles or fire during use, which has brought a greater impact on the personal and property safety of consumers. Therefore, textiles need different degrees of flame retardant finishing, so that it can not only provide consumers with material needs, but also effectively improve safety. With the advancement of textile technology and the continuous improvement of people's living standards, the research on flame retardant finishing of textiles has also been further developed, and certain research results have been achieved. Production method of textile flame retardant fiber Different from ordinary fibers, flame retardant fibers have good flame retardancy and can delay the spread of fire. Flame retardant fibers can be divided into two categories, one is that the fibers themselves have certain flame retardant properties, such as poly-m-phenylene isophthalamide fibers, polyamide-imide fibers, etc., which have been widely used in various High temperature resistant and flame retardant working environment; the other type is obtained by modifying conventional fibers.
2022 / 01 / 22
Flame retardants fulfil their purpose primarily by either physical or chemical action. Physical action can be subdivided into three modes; 1. Cooling: An endothermic process is triggered by additives cooling the substrate to a temperature below that required for sustaining the combustion process. 2. Formation of protective layer: The combustible layer is shielded from the gaseous phase with a solid or gaseous protective layer. The oxygen required for the combustion process is excluded and heat transfer is impeded. 3. Dilution: Fillers are incorporated that evolve inert gases on decomposition diluting the fuel in the solid and gaseous phase so that the lower ignition limit
FLAME RETARDANTS AND THE FUTURE
2022 / 01 / 22
It`s famously said [Prediction is very difficult, especially if it`s about the future." Fire safety will surely remain a primary requirement for electronic and electrical equipment. In order to ensure fire safety, there will be a need to incorporate flame retardants into plastic systems forming part of such electronic and electrical equipment that would otherwise pose a significant fire safety risk. Halogenated materials form by far the largest group of flame retardants used in PCB materials with a global estimated market
Effect of ACR impact modifier for PVC toughening mechanism properties
2022 / 01 / 20
ACR impact modifiers generally refer to crosslinked low glass temperature (Tg) acrylate monomer polymers such as polypropylene Butyl butyrate (PBA) as the core, with poly (methyl methacrylate) and other high Ts polymers as the shell, with two layers Or multilayer core-shell composite polymer. It can not only effectively improve the impact strength of polyvinyl chloride (PVC), but also be used In polymethyl methacrylate (PMMA), polystyrene (PS), nylon and polycarbonate (PC) brittle or low toughness polymers Toughening modification. When ACR is used for toughening PVC, it can be achieved at a low dosage (generally 6-8phr)
Effect of ACR impact modifier for PVC toughening mechanism properties
2022 / 01 / 20
ACR impact modifiers generally refer to crosslinked low glass temperature (Tg) acrylate monomer polymers such as polypropylene Butyl butyrate (PBA) as the core, with poly (methyl methacrylate) and other high Ts polymers as the shell, with two layers Or multilayer core-shell composite polymer. It can not only effectively improve the impact strength of polyvinyl chloride (PVC), but also be used In polymethyl methacrylate (PMMA), polystyrene (PS), nylon and polycarbonate (PC) brittle or low toughness polymers Toughening modification. When ACR is used for toughening PVC, it can be achieved at a low dosage (generally 6-8phr)
Effect of ACR impact modifier for PVC toughening mechanism properties
2022 / 01 / 20
ACR impact modifiers generally refer to crosslinked low glass temperature (Tg) acrylate monomer polymers such as polypropylene Butyl butyrate (PBA) as the core, with poly (methyl methacrylate) and other high Ts polymers as the shell, with two layers Or multilayer core-shell composite polymer. It can not only effectively improve the impact strength of polyvinyl chloride (PVC), but also be used In polymethyl methacrylate (PMMA), polystyrene (PS), nylon and polycarbonate (PC) brittle or low toughness polymers Toughening modification. When ACR is used for toughening PVC, it can be achieved at a low dosage (generally 6-8phr)
Selection of PVC impact modifier
2022 / 01 / 20
Selection of PVC impact modifier The selection of anti-impact modifiers should pay attention to the following aspects: 1, and PVC resin compatibility should be moderate, if the compatibility is too large, two completely molecular level mixing, Impact modifiers may act as plasticizers, adhering closely to the PVC molecules so that the impact force acts directly It can not improve impact resistance on P V C chain. On the contrary, if the two compatibility is too small to reach even points Loose, lost the adhesive force of PVC, unable to absorb the impact force. 2, the glass temperature is low, can improve the impact resistance of PVC at low temperature. 3, the molecular weight should be high, if necessary, the best light crosslinking, in order to improve the enhancement effect. 4. It has no obvious influence on the performance and physical properties of PVC. 5, weather resistance should be good, small swelling from the mold. 6. Good blending with PVC. 7, heat resistance (deformation resistance, thermal stability) better. 8. Economy. Any modifier is not perfect, so in addition to paying attention to the above aspects in the selection, Also look at its main function
Properties and application of acrylic impact modifiers
2022 / 01 / 20
Properties and application of acrylic impact modifiers Because acrylate is the "core-shell" structure of the elastomer, give it a series of advantages: excellent impact resistance "core-shell" structure of the impact performance is better than the network structure of polymer (CPE, EVA). In terms of glass transition temperature, CPE is -10℃ ~ -20℃, while acrylate can reach -56℃, so low temperature impact performance is significantly better than CPE. The newly developed TIM812 glass transition temperature can reach above -60℃, improving the low temperature impact performance of profiles significantly. CPE processing temperature range is narrow because of the chlorinated polyethylene structure Close to PVC, high temperature (185℃), good incorporation, easy to damage the network structure, resulting in impact resistance Drop. If the temperature is low, plasticizing is not good, poor dispersion, but also affect the impact, appearance and other properties of propylene Acid ester anti-impact modifier does not have the above problems, processing temperature is wider, easy to operate, high yield, stable production Low thermal shrinkage, good dimensional stability using A C R impact modifier P V C profile general 100℃, 60 minutes of low shrinkage, generally below 1.5%. CPE is higher, generally above 1.5% (standard requirements ≤2.5%). The practical significance of this project is to test the longitudinal stress of P V C profiles. The influence factors of longitudinal stress are the gelation degree of plasticization and the speed of process traction. Therefore, the residual stress between molecules is too large, and the local concentration is more concentrated, which is the main reason of stress cracking of P V C profile. The ACR resistance The impact modifier has obvious effect on improving the stress cracking of profiles, and the cracking is less in low temperature assembly. ACR impact modifier has a reasonable
2022 / 01 / 19
PVC hose is actually polyvinyl chloride, and PVC is widely used. Widely used in construction materials, industrial products, daily necessities, floor leather, pipe, packaging film, foam materials and many other aspects. PVC is a popular synthetic material today. The PVC process is very strict, and PVC is widely used in the building materials industry because PVC has unique performance characteristics. PVC has the characteristics of rainproof, fireproof, antistatic and easy forming. It also has high light resistance and fire resistance. It has the characteristics of flame retardant and is widely used in fire protection. PVC has a variety of appearances. It not only has simple craftsmanship and excellent performance, it can also express natural colors and people`s desired colors, and can present rich colors. PVC pipe is completely non-toxic and tasteless, and it has no harm to human body. It is an environmentally friendly material. It can protect the ecological environment, so it is the trend of social civilization development. PVC materials meet the needs of the building materials industry and have become the perfect home products for environmental protection and practical use.
2022 / 01 / 19
PVC can be divided into soft PVC and hard PVC. Hard PVC accounts for about 2/3 of the market, and soft PVC accounts for 1/3. Soft PVC is generally used for the surface of floors, ceilings and leather, but because soft PVC contains plasticizer (this is also the difference between soft PVC and hard PVC), the physical properties are poor (such as the water pipe needs to withstand a certain water pressure, soft PVC It is not suitable for use), so its scope of use has been limited. Hard PVC hose does not contain plasticizers, so it is easy to form and has good physical properties, so it has great development and application value. In the production process of PVC materials, it is necessary to add several additives, such as stabilizers, plasticizers, etc. Novista provide the environmental protection additives, impact modifies and PVC stabilizers for the customers to produce PVC pipes who have non-toxic, tasteless and environmentally friendly requirements.
2022 / 01 / 19
PVC piping is commonly employed in the chemical industry. PVC has excellent chemical resistance to wide range of corrosive fluids. UV resistance of PVC piping PVC piping undergoes surface oxidation and embrittlement by exposure to sunlight over a period of time. The color of pipe changes from gray to white. The strength of piping is not reduced, however it becomes more susceptible to impact damage. UV protection can be provided by applying a thick coating of latex paint. Heat tracing of PVC pipe It is possible to heat trace PVC piping to maintain a constant elevated temperature. Electric tracing is recommended. The maximum heat trace temperature should not exceed the pressure temperature rating of the piping system. Pipe supports Pipe saddle cut from PVC pipe are recommended at support locations. PVC pipe must not rest directly on steel. Supports must be provided on or close to inline items such as valves. PVC piping connected to vibrating equipment's such as pumps must be isolated using teflon or rubber expansion joints. Joining Methods - Solvent Welded Joints - Flanged Joints - Threaded Joints Solvent cementing is a preferred method of joining PVC pipe and fittings. The OD of the pipe and ID of fitting are primed, coated with special cement and joined together. Most solvent cement joints fail due to lack of solvent penetration or inadequate primer application. Applicable Standards ASTM D1785 - Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120 ASTM D2241 - Standard Specification for Poly(Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series) ASTM D2665 - Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Drain, Waste, a
2022 / 01 / 15
Types of fire retardant coatings can be defined in many ways and can usually be classified as follows: From the base material it uses, it can be divided into organic type and inorganic type. The organic type fireproof coating is based on natural or synthetic organic resin and organic emulsion; the inorganic type fireproof coating is based on the inorganic adhesive. According to its fire protection form, it can be divided into non-intumescent and intumescent. According to its scope of use, it can be divided into steel structure fireproof coating, prestressed concrete floor fireproof coating, tunnel fireproof coating, etc. Usually, we divide it from the form of fire retardant coating, which can be divided into intumescent and non-intumescent fire retardant coatings. When the non-intumescent fire retardant coating is exposed to fire, the coating basically does not change in volume, forming a glaze-like protective layer. It can act as a barrier to oxygen, so that oxygen cannot contact with the protected flammable substrate, thereby avoiding or reducing the combustion reaction. Since the non-intumescent fire retardant coating is generally thicker than the intumescent fire retardant coating, its consumption per unit area is large, the use cost is high, the decorative effect is poor, and its fireproof and heat insulation effect is not as good as that of the intumescent fire retardant coating. The research on fire retardant coatings for cables and cables generally takes the "intumescent" technical approach.
2022 / 01 / 15
Flame retardants are compounds, which when added to materials during or after manufacture, inhibit or suppress the combustion process. They interfere with combustion at various stages of the process, e.g. during heating, decomposition, ignition or flame spread. Their primary function is to suppress the spread of fires or delay the time of flashover so that people can escape. Flame retardants used in plastic materials fall broadly into two categories, namely additive and reactive. Additive flame retardants are incorporated and dispersed into the plastic prior to, during, or most commonly following polymerization. If they are chemically compatible with the plastic, they act as plasticizers otherwise, they are considered as fillers. Reactive flame retardants are chemically bound to the polymer molecule by incorporating them into the polymer backbone or by grafting them onto the backbone as branches. As reactive flame retardants are chemically bound to the host polymer, they are prevented from bleeding out; and thus generally exert greater flame retardancy than additive compounds due to their greater availability throughout the life cycle of the polymer into which they are incorporated. Novista Group supplies equivalent of FP-2100JC, FP-2200S, FP-2500S, Exolit OP1230, OP930, OP1312, OP1314 to global market.
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