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Nylon (Polyamide，PA) is a type of engineering plastic with excellent overall performance, featuring high strength, good wear resistance, excellent self-lubrication, and high chemical resistance. It is widely used in the automotive, electrical and electronics, machinery manufacturing, and home appliance industries. However, nylon is a flammable polymer, and its combustion process is accompanied by high-temperature thermal decomposition and smoke release. Its insufficient flame retardancy limits its application, particularly in the electrical and electronics and transportation sectors. Therefore, modifying nylon by adding flame retardants is an important means of improving its safety performance.     1. The Mechanism of Action of Flame Retardants in Nylon Materials The primary function of flame retardants in nylon is to inhibit or delay the material's combustion process, thereby reducing the risk of fire. These mechanisms can be categorized as follows: Gas-Phase Flame Retardancy Flame retardants decompose at high temperatures to produce non-combustible gases (such as water vapor, carbon dioxide, and nitrogen). These gases dilute the concentration of combustible gases and oxygen in the combustion zone, thereby suppressing the spread of flames. A typical example is a nitrogen-containing intumescent flame retardant system. Condensed-Phase Flame Retardancy During combustion, flame retardants promote the formation of a dense carbonized layer on the polymer surface, isolating the transfer of heat and oxygen into the material. Phosphorus-based and intumescent flame retardants often exhibit this mechanism of action in nylon. Free Radical Capture Halogen-based flame retardants release hydrogen halides during combustion, which react with high-energy free radicals (H·, OH·) in the flame zone, interrupting the combustion chain reaction and rapidly suppressing the flame. Heat-absorbing and cooling effects Some inorganic flame retardants (such as aluminum hydroxide and magnesium hydroxide) absorb a large amount of heat during decomposition and release water, lowering the surface temperature of the material and slowing the rate of pyrolysis.   2. Common Flame Retardant Types for Nylon Materials For nylon 6, nylon 66, and other grades, different flame retardant systems have their own advantages and applicable scenarios: Halogenated Flame Retardants Representatives: Decabromodiphenyl ethane (DBDPE), Decabromodiphenyl ether (BDE-209) Advantages: High flame retardancy, achieving a high flame retardancy rating (UL 94 V-0) with a small addition amount. Disadvantages: May release toxic gases during combustion, subject to numerous environmental regulations. Phosphorus-Based Flame Retardants Representative Types: Red Phosphorus, Expanded Ammonium Polyphosphate (APP), and Organophosphates. Advantages: Halogen-free and environmentally friendly, with significant condensed-phase flame retardancy and low smoke emissions. Disadvantages: Red phosphorus is highly hygroscopic and requires surface coating; some organophosphorus flame retardants have limited heat resistance. Inorganic flame retardants Representative varieties: aluminum hydroxide (ATH), magnesium hydroxide (MDH). Advantages: Low price, non-toxic and environmentally friendly, low smoke density. Disadvantages: High addition levels (typically >40%) may significantly reduce the mechanical properties and processing flow of nylon. Nitrogen-Based Flame Retardants Representative varieties: melamine salts, cyanurates, etc. Advantages: Can be combined with phosphorus-based flame retardants to create a synergistic effect, resulting in high flame retardancy and environmental friendliness. Composite flame retardant systems Common combinations include phosphorus-nitrogen and phosphorus-halogen. These systems achieve highly effective flame retardancy through multiple synergistic mechanisms, while also improving mechanical properties and heat resistance. 3. The Impact of Flame Retardants on Nylon Properties While achieving flame retardancy, the addition of flame retardants will affect other properties of nylon, requiring a comprehensive balance in formulation design: Mechanical Properties Excessive amounts of inorganic filler-based flame retardants can increase material brittleness and reduce impact strength. Surface coating and glass fiber reinforcement can mitigate the loss of mechanical properties. Thermal Properties Halogen-based and some phosphorus-based flame retardants have little effect on thermal decomposition temperature, but may affect heat distortion temperature (HDT). Highly heat-resistant phosphorus-based flame retardants are more suitable for high-temperature environments such as automotive engine compartments. Processing Performance Highly filled systems increase melt viscosity, affecting injection molding and extrusion efficiency. Red phosphorus flame-retardant nylon places high demands on processing equipment and must be protected from oxidation and corrosion. Long-term Stability Some flame retardants carry the risk of migration and precipitation, potentially affecting appearance and electrical properties. Selecting flame retardants with good compatibility and high thermal stability is key to improving durability. 4. Conclusion and Development Trends The application of flame retardants in nylon materials is not only a necessary means of improving flame retardancy but also a key to expanding its application in high-safety fields. Future development trends include: Environmentally friendly and halogen-free: In response to regulatory requirements such as RoHS and REACH, we are promoting halogen-free phosphorus-nitrogen flame retardants. High efficiency and low dosage: We are developing highly effective flame retardant systems to minimize adverse effects on substrate properties. Functional integration: We combine reinforcement, wear resistance, and antistatic properties to achieve multi-purpose applications. Process-friendly: We are improving the thermal stability and dispersibility of flame retardants to meet the needs of efficient production. By rationally selecting the flame retardant system and optimizing the formula, nylon materials can meet strict flame retardant standards while maintaining excellent mechanical properties, thereby playing a greater role in the automotive, electronics, rail transportation, aerospace and other fields.

Ca-Zn) stabilizers are becoming the go-to choice for PVC products. Here's why they’re a great option: 1. Eco-Friendly and Non-ToxicThey are free from lead and heavy metals, making them safe for food packaging, toys, and medical use. Fully compliant with ROHS and REACH. 2. Good Heat StabilityCa-Zn stabilizers protect PVC from breaking down during high-temperature processing, helping products keep their shape and color. 3. Better AppearanceThey offer good transparency and surface quality—ideal for clear and glossy PVC products. 4. Wide ApplicationSuitable for both rigid and flexible PVC, used in pipes, profiles, cables, films, and flooring. 5. Future-Proof ChoiceWith global demand for safer and greener materials, Ca-Zn stabilizers are a smart, sustainable solution.

  Chemical Name: Antimony trioxide Molecular Formula: Sb2O3 Molecular Weight: 291.52 CAS No.:1309-64-4 EINECS No.: 215-175-0

ProFlame-AT1113 Masterbatch is made from Antimony trioxide(Sb2O3),Synergist and carrier EVA. It is made by special powder processing technology and selecting suitable formula, with good compatibility and fluidity. The high concentration of masterbatch AT1113 can replace powder Sb2O3 by 1:1 ratio, keeping the same flame retardant performance and physical properties, and reduce the cost of formulation. It can eliminate the inhalation of dust and skin contact of powder in producing. The Advantages: √ High cost-performance to replace Sb2O3 powder. √ Dust free to protect workers and the workshop. √ Zero material loss in the production process. √ Good dispersity in resin ensures good FR performance of the final products. √ Good melting flow due to the small M/B granule size and proper carrier resin. √ Easier handling and easier cleaning of the screws. Application: ProFlame-AT1113 Masterbatch can be incorporated to a polymer in conjunction with flame retardant and other additives directly. It is applicable in polymer such as PA6, PA66, ABS, PP, PE, PBT, PVC, HIPS and rubber etc. Recommended dosage: AT1113 can replace powder Sb2O3 by 1:1 ratio in formula. Package and Storage: 25 Kg PP bag with PE liner ; 22,000 KG with pallet loaded in 20'container

Technical Data Sheet DOPO derivatives ProFlame® P2064   CAS NO.: 1239439-38-3 Chemical Formula: C26H20O4P2 Other Name: DI-DOPO P2064 is a novel DOPO derivatives flame retardant containing biphenyl and phenanthrene ring structures, with higher thermal stability and better chemical stability. The characteristics are high efficiency flame retardancy, low dosage, halogen-free and non corrosive, easy to use, and suitable for high processing temperatures. The hydrolysis stability and thermal stability are higher than those of general phosphate esters. P2064 has a higher phosphorus content than traditional phosphate flame retardants and an initial decomposition temperature above 350°C. It is suitable for engineering plastics that require high-temperature processing and certain general plastics. Due to the plasticizing effect of ordinary phosphate flame retardants and their significant impact on physical properties such as HDT, P2064 can be considered for halogen-free flame retardant applications that require transparency and high physical properties. Advantage ◎Special phosphate ester structure can achieve high flame retardant effect. ◎As it is a glassy flame retardant, can achieve transparent flame retardant effect corresponding to some types of resins. ◎Has high thermal and hydrolytic stability. ◎Easy to process, minimal migration. Technical Data Items Spec Appearance White powder Melting Point(°C) 2064A ≥250                                2064A ≥295 Water Content(%) ≤0.3 Phosphorus Content(%) ≥13.5 Particle size D50(um) ≤5.0 1% TGA(°C) ≥355   Application Especially suitable for printed circuit boards that require halogen-free and lead-free solder. In high temperature resistant transparent films and fiber products such as PC, PA, PET, PMMA, and epoxy resins, only a small amount of flame retardant is required to meet flame retardant requirements such as UL-94 V0.

Technical Data Sheet ProFlame® B401 Product Name: Tetrabromobisphenol A bis (allyl ether) Molecular Formula: C21H20Br4O2 Molecular Weight: 624 CAS No.: 25327-89-3   Tech Spec: Item                                                          Index Appearance                                     White Powder Content of bromine ( % )                     ≥51.0 Melting Point (ºC)                                 ≥117 Loss on Drying max (LOD %)                ≤0.3 Assay,%                                                  ≥98.0   Application: B401 is an aromatic brominated flame retardant that is especially efficient, as an additive flame retardants for EPS and in foam polystyrene. The unsaturated end groups provide unique function of initiating the flame retardant’s performance. Package & Storage 25kg paper bag with PE inner bag. Should be stored in dry and ventilated storeroom. This product is non-dangerous. For other operations, please refer to SDS instructions provided by the manufacturer.

PN59是有机次膦酸金属盐环保型无卤阻燃剂，主要用于聚酯、聚酰胺的注塑成型和纤维应用。阻燃聚酯、聚酰胺 化合物表现出非常好的物理和电气特性。   产品优点：： 1.通过结合气相和凝固相的作用方式实现阻燃效果 2.良好的着色性 3.不水解、不析出 4.加工性能好 5.好的物理及电性能 6.低烟、无毒 7.无卤阻燃剂，具有良好的环境和健康特性     主要用途： 用于 PET 纤维时，推荐用量为 5-10%，须在纺纱工艺之前将 PN59 加入聚对苯二甲酸乙二醇酯化合物中; 在聚对苯二甲酸丁二醇酯中，添加 10-15%和 10-15%的氮增效剂（如磷酸三聚氰胺或氰尿酸三聚氰胺）可以获得 电气元件的 UL-94 V0 级别 (1.6 和 0.8 毫米厚度)。 在聚对苯二甲酸乙二醇酯中，只需较少的阻燃剂即可达到 UL-94 V0 标准。 根据不同的聚合物等级、加工条件和玻璃纤维增强剂，阻燃剂用量可能有所不同。     加工建议及注意事项： 1. 加入 PN59 之前，务必要预干燥聚酯。预干燥之后，聚对苯二甲酸丁二醇酯的水分应低于 0.05%（按重量计）， 而聚对苯二甲酸乙二醇酯的水分应低于 0.005%。 2. 并非一定要预干燥 PN59，如果必须避免非常低的水分含量，建议进行预干燥（120℃，4 小时）。     包装与规格： 本品用纸塑复合袋包装，每袋净重 20-25±0.1Kg。            

ProFlame-PN1131 is formulated flame retardant based on organic phosphorus component. It is suited for both GF-reinforced and unreinforced PA6 system. The polyamide compounds exhibit good physical and electrical properties with PN1131.   Processing instruction: 1. Pre-drying the polyamide,the moisture content should be below 0.1 % (by wt.). 2. The optimum conditions for incorporating should be determined in each individual case. Care must be taken to ensure homogeneous dispersion of all components. 3. The temperature of the polymer melt should not exceed 320 °C. 4. It is most suitable for equipment with weak shear force. 5. The processing temperature of Parallel twin-screw extruder should keep between 210 ~ 245 ℃ with vacuum at the same time.The temperature is too high, the physical property loss of PA6 is large, and the yellowing is also large. 6. Do not use low-alkali or high-alkali fiberglass. High-quality non-alkali fiberglass is preferred.  

  PNPO-G3 is a halogen-free flame retardant , which develops its effectiveness through phosphorus / nitrogen synergism. When incorporated into thermoplastics, which can meet the requirement of UL94- V0(0.75-1.6mm), GWIT 750°C, GWFI 960°C .Meanwhile ,PNPO-G3 can pass 70°C*168hrs water immersion test (UL746C) and meet ROHS and REACH environmental regulations .  In glass fiber reinforced PP system, the flame retardant efficiency of PNPO-G3 is 8-10% higher than ADEKA FP-2500S, so the dosage can be reduced by about 2%, which has less effect on mechanical property and lower cost. Benefits •Compared with bromine-antimony flame retardant, the product density is lower and the comprehensive cost of formula is lower • With high thermal decomposition temperature , excellent heat aging resistance and excellent UV stability, it can adapt to a wide range of processing technology and application • Compared with traditional ammonimum polyphosphate flame retardant,it has excellent water resistance • Low smoke density and low smoke gas corrosivity,good recyclability   Technical Data Items                                                                             Spec Appearance                                            White free-flowing powder Phosphorus content, %                                              19-22 Nitrogen content, %                                                   17-20 1% TGA Temperature, °C                                            ≥260 Average particle size, um                                            ≤10 Whiteness                                                                     ≥90 PH Value(10% suspension in water at 25°C)             3-5 Bulk density,g/cm3                                                                             0.35-0.55   Recommended dosage Polymer                                                Usage guide PP with 30%GF                          UL94 V-0(1.5mm) - 20-21wt%                                                                                    UL94 5VA(2.0mm) - 28-30wt% PP                                      UL94 V-0(1.6mm) - 18-20 wt% with 0.2% PTFE                                                       UL94 V-0(1.6mm) - 25 wt% without PTFE                                          UL94 5VA(2.0mm) - 30-35 wt% LDPE & EVA                                         UL94 V-0(1.5mm) - 24-26 wt% (with 0.2% PTFE)                                        UL94 V-0(1.5mm) - 28 wt% (without PTFE) HDPE                                              UL94 V-0(1.6mm) - 30-35 wt% TPE                                                    UL94 V-0(2.0mm) - 32-35 wt%

ProFlame-AT3506 Masterbatch is made from Antimony trioxide(Sb2O3) and carrier PVC.It is made by special powder processing technology and selecting suitable formula, with good compatibility and fluidity. The high concentration of masterbatch AT3506 can replace powder Sb2O3 , keeping the same flame retardant performance and physical properties, and reduce the cost of formulation.It can eliminate the inhalation of dust and skin contact of powder in producing. The Advantages: √ Dust free to protect workers and the workshop. √ Zero material loss in the production process. √ Good dispersity in resin ensures good FR performance of the final products. √ Good melting flow due to the small M/B granule size and proper carrier resin. √ Easier handling and easier cleaning of the screws.   Application: ProFlame-AT3506 Masterbatch can be incorporated to a polymer in conjunction with flame retardant and other additives directly.It is applicable in polymer such as PVC,ABS and rubber ect.

High molecular weight, superior mechanical performance, general impact modifier for plastic rigid products and semi-flexible products Comparable grade Tyrin® T-3615 Tyrin® T-7000 Tyrin® T-6000    

Today we recommend several flame retardant solutions that can reduce costs. Option 1: For non-filled, non-reinforced flame retardant PP, it is recommended to use our halogen-free flame retardant PNPO series. Its main ingredients are high polymerization ammonium polyphosphate and hyperbranched macromolecule triazine carbon-forming agent. It has high flame retardant efficiency and significant cost advantages. Adding the amount between 25-30% can reach 1.6mm UL94 V-0 flame retardant level. Option 2: Fill or enhance flame-retardant PP. It is recommended to use our halogen-free flame retardant PNPO-G. Its composition does not contain ammonium polyphosphate, has very good hydrolysis and temperature resistance, and will not decompose in the glass fiber system. In a 30% glass fiber system, only 21-23% is added to achieve the 1.6mm UL94 V-0 flame retardant level, and the product has excellent anti-UV stability. Both of the above solutions greatly reduce the cost of flame-retardant PP, and change from a halogen-containing system to a halogen-free system with better environmental performance. Especially for downstream export orders, the selling point and attractiveness are greatly enhanced.   Although the plastics industry is not very prosperous, it is the last word to continue product innovation and cost control so that downstream customers can get tangible results! .

  TF-530 is a high molecular weight acrylic process aid that brings enhanced processability to high output extrusion, foam and highly filled compounds such as those found in wood-polymer composites. Benefits: ● Recommended for applications where very high hot melt strength is critical. ● In high output extrusion formulations, TF-530 provides the unique combination of quick fusion with low viscosity that maximizes output. ● Providing a uniform, closed-cell structure in cellular PVC.

Effect of CPE with different tensile strength and elongation at break on PVC modification: Tensile property is also the key performance index of CPE materials, and the tensile property of materials is characterized by tensile strength and elongation at break. The tensile properties of CPE are closely related to the raw material HDPE, chlorine content, chlorine atom distribution, melting enthalpy (residual crystallinity) and Shore hardness. Elongation at break is also a measure of the toughness of CPE indicators, HDPE selection, chlorine content, chlorine atom distribution, melting enthalpy (residual crystallinity) and the level of elongation at break has a great relationship, different application field requirements are also different. Because the elongation at break is closely related to Shore hardness, the current industry standard HG/T2704-2010 only Shore hardness does not require the elongation at break.   According to experience and application verification, the elongation at break of the PVC impact modified CPE135A reaches 650%, that is, it has a comprehensive balance of technological and mechanical properties. Under normal circumstances, for rigid PVC modification, the elongation at break of CPE135A can basically meet the requirements of toughening when it reaches more than 650%; Considering the strength of the product, it is not considered that the higher the elongation at break, the better, because CPE is too soft or the elongation at break is too high will inevitably affect the strength of the product, the product strength reflected in the application of PVC profiles and pipes is tensile strength, bending elastic modulus and welding strength, adding too much CPE, tensile strength and welding strength will usually be reduced. So you need to find a balance between strength and toughness. However, for PVC products that require better low-temperature toughness, such as power pipes used in cold areas, better low-temperature toughness is needed. According to the comparative test of CPE with high elongation (> 800%) and low elongation (800-600%), it was found that the elongation at break of CPE had little effect on the plasticization speed of CPE modified PVC composite, and the plasticization speed of CPE with high elongation was slightly faster.   CPE with high elongation is superior to CPE with low elongation in low temperature toughness of PVC profiles and power pipes. The tensile impact strength of CPE with high elongation is also slightly higher. The low temperature performance of CPE with high elongation is better than that of CPE with low elongation, which has advantages in the low temperature bending performance of power pipe.

Effect of CPE with different impurity particle number on PVC modification: Impurities in CPE usually refer to particles in CPE that are not plasticized or difficult to plasticize, such as hyperchlorinated CPE, yellow discolored particles, mixed with other material impurities, etc., which can usually be found by CPE spot pressure film test. This impurity particles exist in every manufacturer, but how much to say, because the reaction is not entirely possible in the chlorination reaction, the reaction time will be long, and the reaction kettle will not be clean, so this is the manufacturer's production process problem.   The impurity particles in CPE are often difficult to plasticize, and it is easy to show on the surface of its modified PVC products, especially the thin product surface is easy to identify, sometimes you will find small points on the surface of the product, and sometimes you will find concave in the opposite direction, and the color is slightly yellow than the color of the product. General impurities will be concave when exiting the die, and will be flat after cooling. These impurities not only affect the appearance of the product, but also fatal defects in PVC products, when the filling becomes high, it will break from the impurity point, seriously affecting the toughness of the product.   In addition, impurity points on the surface of PVC products also appear as white particles or pits on the surface of products. When the elemental analysis of the white particles was carried out, it was found that it was mainly the composition of the calcium mixed lubricant, which may be caused by the agglomeration of calcium carbonate if the CPE is plasticized quickly when mixing at high temperature.   Although impurity particles are difficult to eliminate, but still need to control, light industry standard QB/T5079-2017, not more than 50 /100g impurity content is still necessary.  

ProFlame® RTF-100   Sb2O3 is commonly used as synergist in halogenated FR systems. But as antimony reserves worldwide are decreasing, Sb2O3 price is rising all the way up. Consequently, the cost for FR- treated products is also rising, compressing the profit margin for manufacturers.RTF-100  is  an  replacement  of  Sb2O3.  It  can  replace  Sb2O3  in halogen-antimony FR systems in an effective way with lower cost.   Physical and Chemical Index: Product name                        RTF-100 Whiteness,%                           >95 Average Particle size,um  0.6-1.1 Moisture,%                          <0.1 As2O3,%                           <0.04 PbO,%                               <0.065 Fe2O3,%                               <0.004 Se,%                              <0.0015 CuO,%                               <0.0035   Characters: 1.  High  purity,  high  specific  surface  area,  ultrafine  particles’  surface  effect  and volume effect, good thermal stability, no skin irritation, no odor, no corrosion. 2.  Good heat resistance 3.  RTF-100 can replace 100% Sb2O3 , thus saving cost. 4.  RTF-100 can help to maintain products’ mechanical and electrical performance in hot and damp environment.   Application Range: It is mainly used in PVC cable & wire , PP,PE,ABS,HIPS and so on.   Package 25kg plastic woven bag or paper bag with PE liner bag.   Storage considerations: The product can be stored under appropriate conditions for two years. But please keep products store in a dry ventilated environment (temperature should not exceed 30°C, in low humidity).  Especially at high temperatures & high humidity, it is recommended not to stack more than 30 days long.

Effect of CPE with different ash mass fraction (ash) on PVC modification: In order to prevent CPE from caking, the line label stipulates that no more than 5% calcium powder can be added to CPE as a spacer. The regular manufacturers use mostly ultra-fine light calcium carbonate, which has high fineness, good dispersion effect, and can effectively and evenly cover the surface of CPE particles, playing a good isolation and anti-caking role. Although it is true that there will be a little dust in the sensory touch, it does not affect the toughness, tensile strength, plasticizing performance and other indicators of CPE, and can be used with confidence.   In recent years, in order to fill up and reduce costs, some manufacturers began to use granular calcium as a CPE isolator, granular calcium is composed of 85% calcium carbonate, 10% stearic acid, 5% PE wax, coupling agent, plasticizer and other components. Because the particle calcium is small in dust in use, well camouflaged, it is not easy to detect, and some manufacturers fill a large number of them. Due to the large particle size and poor dispersibility after surface treatment of granular calcium, CPE particles can not be effectively coated and isolated, and can not play the role of anti-caking. Due to the large amount of granular calcium added, and containing stearic acid and other lubricant, it will delay the plasticization of PVC products, affecting the toughening effect of CPE, products are easy to brittle, easy to break, especially for the buckle plate, bellow, electrical threading pipe and other thin-walled products, more likely to lead to brittle products, but also appear on the surface of the product irregular white spots and other phenomena, which is not plasticized granular calcium. Because some CPE manufacturers add a large number of granular calcium, its specific gravity is different from that of CPE, CPE filled with calcium powder is not easy to mix, which results in a large difference in the content of calcium powder between the first packaged CPE and the later packaged CPE even if the CPE product comes out of the same reactor, and some calcium-free powder is close to the CPE pure material, and the CPE calcium content is different in the same batch number. This makes it difficult for users to determine the process, resulting in fluctuations in the quality of pipes, profiles, and gusset plates.   The use of granular calcium will make the impression of small dust in the sense and use of CPE, but it will actually affect the quality of CPE, so do not blindly judge the quality of CPE through the feel when choosing CPE, we must use scientific methods to identify and measure the calcium powder content of CPE.   Whether it is the addition of light calcium carbonate or the addition of granular calcium and heavy calcium, by detecting the calcium ion content of CPE, the added amount of calcium in CPE can be detected, which makes it difficult for CPE manufacturers to achieve the purpose of reducing costs by adding a large amount of calcium powder. In order to detect the calcium ion content of CPE and not detect adulteration, some manufacturers add other inorganic substances such as talc powder, for which the ash index and test method are added to the HG/T2704-2010 chlorinated polyethylene standard. By measuring the mass fraction of CPE ash, the amount of inorganic substances such as calcium carbonate and talc filled into CPE can be quantitatively understood.   Too much inorganic material filling in CPE will lead to delayed plasticization of PVC products, affect the toughening effect of CPE, and make products brittle and easy to break. Therefore, it is necessary to identify and measure the mass fraction of ash according to the scientific method in HG/T2704-2010.

Effect of CPE with different particle size (screen residue) on PVC modification: Chlorination process, grinding and so on have a great relationship, CPE too thick or too fine have a certain impact on PVC modification effect. The suspension chlorination of CPE is a heterogeneous reaction, and the particle size of PE has a significant effect on the uniformity of chlorination. If the particle size is small, the specific surface area of the particles is large, the chlorine atoms are easy to penetrate into the particles, and the chlorination is more uniform. If the particle is too coarse, the infiltration of chlorine into the particle is difficult, and the chlorination is not uniform. It was found through experiments that the thickness of CPE particles produced from the same PE raw material also had a certain impact on the rheological properties of CPE, which showed that the plasticizing performance of CPE with excessively fine particles was slightly worse than that of CPE with coarse particles, and the plasticizing time was delayed.   The influence of CPE particle thickness on PVC modification is also related to the change of PVC powder particle morphology during PVC/CPE hot mixing. PVC powder particle size is different at room temperature, in the extrusion molding process is easy to cause plasticization is not uniform, when the mixing temperature reaches about 120 ° C, the particles become large and uniform, small particles almost completely disappear, and in a part of the particles or edges become transparent or translucent, this phenomenon shows that PVC particles due to absorb heat and produce partial gelation, Particle homogenization and the melting of a considerable part of the auxiliaries are the main characteristics of this zone, which is also one of the purposes of hot mixing. However, if the CPE particles blended with PVC are too thick, it is difficult to disperse evenly in the pre-plasticization stage of this mixture and achieve a better pre-plasticization state. In the extrusion process, it is difficult to achieve a good plasticization state, so that it is difficult to form a network structure, and then reduce the impact modification effect of CPE on PVC. This may be related to the toughening mechanism, because CPE forms a network structure in the PVC/CPE system, and the network is easy to deform, especially the polygonal network, which causes shear slip in the 45° direction. It may also be due to the low network strength of CPE (lower than PVC), can not resist the role of external shear forces, shear slip occurs; At the same time, CPE, as a stress concentrator, also causes PVC to shear slip in the direction of 45°. The formation of shear slip dissipates part of energy and improves toughness [7]. If CPE is insufficient to form a network structure in the PVC/CPE system, the impact modification effect of CPE will be reduced. The control index of the light industry standard QB/T5079-2017 is the screen residue (0.9mm sieve hole) ≤2.0%.  

Effect of CPE with different chlorine content on PVC modification: The compatibility of CPE with PVC depends on the chlorine content of CPE and the distribution of chlorine atoms on the PE molecular chain. The amount of chlorine in CPE has a great influence on the modification effect of PVC. After chlorination of the same polyethylene raw material, different chlorine content has different modification effect on PVC. CPE with chlorine content below 25% is not compatible with PVC, so it is not suitable for PVC modification. CPE with a chlorine content of more than 40% has excellent compatibility with PVC, and can be used as a plasticizer for PVC, not suitable for use as an impact modifier; CPE with a chlorine content of 35 ~ 36% has low crystallinity and glass conversion temperature, good elasticity and compatibility with PVC, and is widely used as an impact modifier for hard PVC products. Chlorine content is determined by the production process and ingredients, as long as the production ingredients are determined, the chlorine content is determined after the end of the reaction, although the chlorine content is a key factor affecting the performance of CPE, but it does not mean that it is technically difficult to control, so the chlorine content of the CPE products of various companies is usually no problem, are relatively stable.

Effect of CPE with different Mooney viscosity on PVC modification: Although the CPE industry standard, Mooney viscosity has no requirements for plastic modification materials, but the Mooney viscosity of CPE can reflect the molecular mass of CPE, CPE molecular mass has a significant impact on its physical properties, such as material fluidity, aging resistance, strength and so on. High molecular quality is the product strength is high, but the molecular mass is too large, the viscosity is too large, will make the CPE modified PVC need a higher processing temperature to form, the processing temperature is too high, not only to bring difficulties to the processing process, but also to the quality of the product itself. Therefore, to ensure the physical properties of the product, the PE molecular quality is not required to be too high. The molecular weight of HDPE, a special raw material for CPE, is usually controlled at 100,000 to 150,000. The molecular mass of PE was characterized by the melt flow rate of PE, which was inversely proportional to the molecular mass. CPE Mooney viscosity can also reflect the molecular weight of CPE, high Mooney viscosity of CPE molecular weight is large, low Mooney viscosity of CPE molecular weight is small. According to the experimental results of rheological curves, the rheological properties of CPE are different due to the difference in Mooney viscosity of CPE. The plasticizing time increases with the increase of Mooney viscosity of CPE. The difference in rheological properties is reflected as the extension of plasticizing time and the decrease of extruder torque in processing application experiments. And the reduction of extruder torque and the extension of plasticizing time have certain rules to follow. The rheological properties of materials measured by torque rheometer can truly reflect the processing properties of CPE. The speed of plasticization time corresponds to the level of extruder torque, that is, the plasticization is fast, the torque is high, and the friction heat of materials increases at this time. Slow plasticizing, low torque, less friction heat generated. Although the experimental formula and processing conditions are different, it will not affect this trend [5]. It is found that the PVC/CPE composite profiles made from CPE with high molecular weight have higher properties and better impact modification effect. For low molecular weight CPE, the impact strength of its PVC/CPE composite has a downward trend [6]. Therefore, in practical applications, it is not the faster the plasticization of CPE, the better the use of CPE, should be combined with the actual production formula and processing technology of the processing manufacturer to select.