HiSiaddi is an innovative foreign trade service provider driven by both technology transformation and export business. We operate a service system defined as "1+2+3+4=1" and can supply PVI rubber vulcanizing agents sourced directly from multiple well-known original manufacturers. As a tech-driven foreign trade enterprise, HiSiaddi has long collaborated with factories on technology conversion and accurately captured market demands, repeatedly resolving customized formulation requirements for PVI rubber vulcanizing agents. Below is a case detailing how HiSiaddi delivered a fully customized PVI solution to meet unique client specifications.
Contact HiSiaddi customer service for inquiries about customized product services.
Purchaser: Elastomer-Tech GmbH, Stuttgart, Germany A long-established European Tier 1 automotive rubber component supplier specializing in composite fluororubber + EPDM sealing gaskets and transmission oil seals for Mercedes-Benz and Bosch engines. Its products comply with stringent standards including German DIN535, EU REACH, RoHS 2.0 and automotive IATF16949. The client previously purchased refined specialty grades of PVI (N-Cyclohexylthiophthalimide, anti-scorch vulcanizing agent CTP) exclusively from LANXESS Germany. Faced with surging European additive raw material costs and extended lead times, the client planned localized customization of proprietary modified PVI with an annual fixed demand of 190 tons.
After trialing commercially available standard domestic PVI powder on production lines, the client encountered three critical manufacturing defects. Most domestic additive manufacturers only mass-produce general national standard PVI and refused to adjust formulations for special tailored indicators. The client entrusted HiSiaddi Fine Chemical Foreign Trade with full end-to-end delivery of customized formulation development, process fine-tuning, lab testing, pilot trials and mass production rollout.
HiSiaddi has over a decade of experience in customized export of rubber additives, with direct cooperation with 3 major large-scale domestic PVI manufacturers. Our in-house team includes rubber formulation engineers and an independent downstream mixing test laboratory. Unlike ordinary intermediaries that only trade spot goods, we deliver full-chain customized development covering raw material synthesis modification, formulation optimization, mixing compatibility testing with rubber compounds, and complete regulatory compliance support.
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Blooming and whitening on sealing parts caused by high-temperature precipitation of conventional PVI The client adopts a high-temperature mixing process at 215°C paired with high-speed screw extrusion. General industrial-grade PVI contains excessive free phenol and residual intermediates; small molecular substances migrate out under high processing temperatures, forming white bloom on finished oil seals, resulting in direct rejection by vehicle OEMs. Customized requirements: Free phenol ≤22ppm, heating loss ≤0.25%, initial melting point ≥90.5°C.
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Poor dispersion of standard powder PVI leading to uneven premature scorch in high-silica-filled rubber compounds The client’s formulation uses high-loading silica-reinforced EPDM systems. Standard crystalline PVI powder agglomerates during mixing, causing poor dispersion and localized premature scorch that renders batches of rubber unusable. The client requires pre-dispersed granular PVI-80 (EPDM carrier) with 80% active ingredient content, no caking at ambient temperature, and full uniform dispersion within 3 minutes of internal mixing.
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Slight yellow discoloration of general PVI incompatible with white medical-grade automotive rubber accessories The client also manufactures white rubber hoses for on-board water supply systems. Conventional PVI contains trace colored impurities that cause yellowing of finished white rubber parts. Customized requirements: APHA color ≤35, low-color refined PVI with zero heavy metal residues, complying with EU food-contact additive limits.
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Mass production standards of mainstream domestic PVI manufacturers: Free phenol ≥60ppm, powder melting point 88~89°C, no refined pre-dispersed granular grades. Most manufacturers declined customized development due to high R&D and production costs for small-batch tailored orders.
HiSiaddi engineers traveled to Germany to collect samples from the client’s factory, mapped out the EPDM/NBR dual-rubber vulcanization system and accelerator combination (sulfenamide + thiazole composite system), and defined targeted modification directions for PVI:
1. Synthesis optimization: Adjust feed ratios of phthalimide and cyclohexyl chloride, implement secondary negative-pressure rectification purification to reduce residual small-molecule byproducts and strictly control free phenol and TPP impurity levels.
2. Formulation planning: Develop two customized grades separately – high-purity refined powder PVI (for white rubber parts) and EPDM pre-dispersed granular PVI-80 (for black sealing components).
3. Impurity control: Heavy-metal-free catalytic agents used throughout synthesis; finished products supported with third-party SGS food-contact testing reports.
Cooperated with manufacturers to launch a 50kg small trial production line, adjusting synthesis catalytic temperature and purification parameters across three sample batches:
· Sample 1: Free phenol 38ppm, melting point 89.7°C, excessive impurities
· Sample 2: Extended rectification duration, free phenol 26ppm, APHA color 42, slight yellow tint
· Final Customized Sample 3: Free phenol 21ppm, initial melting point 91.2°C, heating loss 0.21%, APHA color 32 – all physical and chemical indicators fully meet client thresholds. Simultaneously developed pre-dispersed PVI-80 granules: EPDM raw rubber as carrier, low-temperature extrusion granulation, stable active ingredient content 79.5%~80.3%, dust-free, no caking after 6 months of ambient storage.
HiSiaddi replicated the client’s 215°C high-temperature mixing process in our cooperative rubber laboratory and conducted 72-hour continuous trial production with customized PVI samples:
1. White EPDM rubber: No yellowing or blooming; scorch time extended by 180 seconds compared to original LANXESS products, with no negative impact on vulcanization rate, tensile strength or compression set.
2. Black engine sealing rubber: Uniform dispersion of granular PVI completely eliminated localized premature scorch, raising rubber yield rate from 76% to 99.2%. A 50kg sample shipment was sent to the German factory for on-site mass production testing, passing all incoming inspection standards at Mercedes-Benz supporting laboratories in one go.
1. Coordinated factory renovation of rectification production lines to establish exclusive customized production lines with balanced monthly scheduling.
2. HiSiaddi provided customized supporting documents: exclusive COA (Certificate of Analysis) for both grades, full REACH-SVHC screening reports, bilingual SDS complying with CLP regulations, and IATF automotive OEM conformity statements to meet German factory incoming audit requirements.
1. Order split for delivery: Total annual 190 tons split into 75 tons of high-purity refined powder (for white pipeline rubber) and 115 tons of pre-dispersed granular PVI-80 (for automotive sealing parts), shipped to Germany in monthly consolidated containers.
2. Cost optimization: Comprehensive procurement cost of domestic customized PVI reduced by 31% versus original LANXESS products; ocean transit lead time shortened from 45 days to 22 days.
3. Follow-up incremental cooperation: The client launched a new new-energy vehicle water-cooled battery sealing rubber project the following year, adding a customized low-temperature modified PVI grade with an additional annual procurement volume of 72 tons.
4. Long-term after-sales service: HiSiaddi conducts pre-shipment physical and chemical testing for every batch, tracks updates to EU additive regulations, and adjusts formulations as needed to comply with new regulatory standards.
Domestic additive manufacturers prioritize mass production of standard national-standard PVI; customized modification requires production line technical upgrades and R&D investment, and manufacturers without foreign trade technical cooperation resources are reluctant to take on niche high-end customized orders. Mid-to-high-end overseas automotive OEMs feature highly differentiated rubber formulations, making standard off-the-shelf additives unable to match unique processing conditions.
Integrating rubber formulation expertise and upstream factory resources, we deliver full-chain customized solutions covering formulation R&D, iterative small trials, pilot verification, mass production launch and compliance support – breaking the limitations of pure spot goods trading and optimizing PVI products from the downstream rubber application perspective to resolve critical production bottlenecks for clients.
European automotive Tier 1 suppliers prioritize formulation matching consistency, stable batch uniformity and full-chain compliance support when purchasing additives. They are willing to pay premiums for exclusive customized products, and end-to-end technical customization capability is the core competitive edge for domestic additives to enter high-end European automotive supply chains.
Contact HiSiaddi customer service to inquire about customized product services.
+86-13120989737 
info@hisiaddi.com 
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