Rongsheng New Materials (Taizhou) Co., Ltd. supplies chlorinated polyethylene grades with residual crystallinity controlled to 2–8 % and chlorine content of 35–36 % for impact modification of rigid poly(vinyl chloride) window profile compounds. Extrusion operations on parallel twin-screw extruders with 92 mm screw diameter and L/D ratio 25:1 require dry blend preparation in a high-speed mixer heated to 120–125 °C, followed by cooling to 45 °C before extrusion. The processing window is narrow because chlorinated polyethylene promotes shear heating and dehydrochlorination at melt temperatures above 200 °C, causing acid-catalysed degradation, plate-out on calibrator surfaces, and brown streak defects. Production-scale outputs of 180–250 kg/h are maintained when melt temperature remains between 185 °C and 195 °C, die head pressure stays between 180 bar and 220 bar, and barrel temperatures follow a reverse profile from 175 °C at the feed throat to 165 °C at the metering zone. Tin mercaptide stabilisers at 1.2–2.0 phr and calcium stearate at 0.8 phr scavenge hydrogen chloride; oxidized polyethylene wax at 0.15 phr reduces metal release from the die land. Chlorinated polyethylene addition at 6–10 phr raises notched Izod impact strength at 23 °C from 4.5 kJ/m² for unmodified PVC to 25–35 kJ/m² when tested according to ASTM D256-10, while tensile strength measured by ASTM D638-14 decreases from 48 MPa to 38–42 MPa. Above 12 phr addition, die swell increases by approximately 8–12 %, and profile wall thickness becomes unstable in multi-chamber hollow sections with wall thickness below 2.5 mm.
Table 1. CPE addition level effect on rigid PVC window profile compound propertiesCPE (phr)Notched Izod at 23 °C (kJ/m²)Tensile strength (MPa)Elongation at break (%)Vicat softening temperature (°C)04.5488824144525798284245761235387073
Why Does Mooney Viscosity Drift During Open Mill Compounding of Chlorosulfonated Polyethylene?
Chlorosulfonated polyethylene grades supplied by Rongsheng New Materials (Taizhou) Co., Ltd. with chlorine content 35 %, sulfur content 1 %, and Mooney viscosity ML(1+4) at 100 °C in the range 30–60 are compounded on open mills with roll temperatures of 40–60 °C and friction ratios of 1.15:1 to 1.25:1. Mooney viscosity measured according to ASTM D1646-19a drifts upward by 4–8 units when atmospheric moisture exceeds 60 % relative humidity because magnesium oxide acid acceptor hydrates preferentially and loses active surface area. The same effect occurs when zinc oxide is used at 3–5 phr without a moisture-barrier package; scavenger efficiency declines because zinc chloride formation competes with zinc stearate formation during early mixing. Production-scale batch weight is typically 35–45 kg on a 550 mm open mill, and batch-to-batch variance of ±3 Mooney units originates from variation in raw polymer chlorine distribution and filler moisture. Cure rheometry by ISO 6502-3:2023 at 160 °C shows minimum torque ML and maximum torque MH differences of 5–9 dN·m; compounds with acid acceptor levels below 4 phr exhibit scorch times Ts2 shortened to 1.2–1.8 min and rapid viscosity rise before sheet cooling. Addition of pentaerythritol at 1–2 phr stabilises the acid acceptor system but increases water absorption after vulcanisation; the final wire jacket compound must be dried to 0.05 % moisture before extrusion on a 60 mm single-screw extruder with L/D ratio 30:1 and screen pack 80/120/80 mesh. Avoid combination with amine-based additives because premature crosslinking occurs during storage at 35 °C within 7 days.
Table 2. Compliance checklist for chlorosulfonated polyethylene wire jacketing compoundsPropertyTest methodTypical production-scale requirementTensile strength after curingIEC 60811-5019–12 MPaElongation at break after curingIEC 60811-501350–500 %Hot set elongation at 200 °CIEC 60811-507≤ 20 %Mineral oil resistanceIEC 60811-404± 15 % retentionOzone resistanceISO 1431-1:2022No cracks at 100 pphm for 96 hLow-temperature bendingIEC 60811-504No cracks at -30 °C
For recycled polypropylene battery case impact modification, a 3 wt% chlorinated polyethylene addition is tumble-mixed at 60 rpm and injection moulded at 210 °C with clamp force 1200 kN; published data for this specific configuration is limited.
When Chlorinated Rubber Is Formulated into High-Solids Traffic Marking Coatings
Formulators processing chlorinated rubber supplied by Rongsheng New Materials (Taizhou) Co., Ltd. into high-solids traffic marking coatings typically select grades with chlorine content 65 % to ensure solubility in low-aromatic solvent blends while retaining film hardness. When xylene is partially replaced by toluene at 20–30 % of total solvent mass, solution viscosity at 25 °C falls below 150 mPa·s at 20 % solids as measured by ASTM D2196-15, but flash point drops below 25 °C, requiring closed-loop ventilation and ATEX-compliant dispersion equipment. Production bead mills with grinding chamber volume 5 L and cooling water at 15 °C can maintain pigment fineness below 20 μm according to ISO 1524:2020; however, high shear above 12 m/s tip speed degrades the chlorinated rubber backbone, increasing polydispersity and reducing binder effectiveness. Wet film thickness between 300 μm and 500 μm applied at 4 km/h line speed yields dry film thickness of 100–180 μm after solvent release, with through-dry time of 10–15 min at 23 °C and 50 % relative humidity as measured by ISO 9117-3:2010. Skid resistance after full cure is typically evaluated by ASTM E303-13, but published data for this specific formulation configuration is limited.
In low-smoke halogenated cable sheathing compounds, chlorinated polyethylene supplied by Rongsheng New Materials (Taizhou) Co., Ltd. functions as both polymeric plasticizer and char-forming halogen source. The typical formulation combines 25–35 phr chlorinated polyethylene with 5–10 phr antimony trioxide and 20–40 phr aluminium hydroxide in an ethylene-vinyl acetate base. Mixing on an internal mixer with 1.5 L chamber capacity at 50 °C initial temperature and rotor speed 40 rpm requires staged addition: polymer and stabiliser first, fillers second, and oil third. Dispersion of antimony trioxide is evaluated by ashing at 550 °C and scanning electron microscopy; aggregates larger than 10 μm cause surface defects during wire extrusion at 120–140 °C. The limiting oxygen index of the compound increases from 22 % to 28–32 % when tested according to ISO 4589-2:2017, while heat release rate under cone calorimetry at 50 kW/m² falls below 250 kW/m² when chlorinated polyethylene content exceeds 25 phr. Cable extrusion lines with single-screw diameter 60 mm and L/D ratio 30:1 require screen packs with 80/120/80 mesh to remove char particles; melt pressure above 280 bar indicates premature crosslinking or filler agglomeration. The compound must be pre-dried to below 0.05 % moisture after storage at 65 % relative humidity or above; otherwise surface roughness appears on the jacket. Compliance with IEC 60332-1-2:2015 flame propagation is achievable at sheath thickness 1.2–1.8 mm, but acid gas emission measured by IEC 60754-2:2011 pH and conductivity remains a limitation for indoor installations.
Acid Scavenger Selection in Chlorinated Polyethylene Geomembrane Compounds
Chlorinated polyethylene geomembrane compounds require an acid acceptor system to prevent autocatalytic dehydrochlorination during long-term contact with municipal landfill leachate. Rongsheng New Materials (Taizhou) Co., Ltd. supplies chlorinated polyethylene grades with chlorine content 25 % and Mooney viscosity ML(1+4) 60–80 for calendered liners of thickness 1.0–1.5 mm. Calendering on three-roll stacks with roll temperature 160–175 °C and melt temperature 155–165 °C requires acid scavengers such as magnesium oxide at 3–5 phr or calcium hydroxide at 2–4 phr; zinc oxide is avoided in geomembrane compounds because zinc chloride formed during acid neutralisation catalyses further degradation and causes black specks. Tensile strength measured by ASTM D638-14 at 23 °C is typically 12–16 MPa, elongation at break 400–600 %, and tear strength by ASTM D1004-13 is 35–50 N/mm. Low-temperature brittleness by ASTM D746-14 remains below -35 °C when plasticizer level does not exceed 15 phr. Carbon black dispersion in geosynthetic applications is assessed by ISO 11358:2018 thermogravimetric analysis and optical microscopy, with agglomerates above 25 μm initiating stress concentrations. Dimensional stability after heat ageing at 115 °C for 168 h requires retention of at least 70 % elongation and 80 % tensile strength; formulations without acid scavenger fail within 48 h due to viscosity increase and surface cracking.
In flexible PVC hose filled with calcium carbonate at 40 phr, a 1.5 phr chlorinated polyethylene addition raises low-temperature brittleness resistance; published data for this specific configuration is limited.
Thermal Degradation Pathways in CPE-Modified PVC at Screw Speeds Above 40 rpm
Thermal degradation pathways in chlorinated polyethylene-modified PVC compounds are relevant to compounding lines operating twin-screw extruders at screw speeds above 40 rpm. Reported activation energies for PVC dehydrochlorination in open literature range from 100 kJ/mol to 150 kJ/mol, depending on stabiliser type; chlorinated polyethylene contributes labile allylic chlorines that accelerate zip elimination when melt temperature exceeds 205 °C. On a 75 mm co-rotating twin-screw extruder with L/D ratio 40:1, screw speed increase from 30 rpm to 60 rpm raises melt temperature by 12–18 °C under adiabatic conditions, reducing the induction period before hydrogen chloride evolution. Wet chemical titration of evolved HCl by ISO 182-1:1990 or conductivity cells downstream of the vent port provides an early indicator; values above 20 ppm in the vent gas correspond to yellowing. Processors lower melt residence time to below 90 s and configure screw elements with two kneading blocks of 30° staggering to limit energy input, but excessive distributive mixing degrades impact performance. Published data for this specific configuration is limited.
