"我要做高端密封和车用弹性体，SEBS还是SEPS？"电话那头的制品厂采购拿不准。我问他工况，要耐高温、耐油、压缩变形小，那就别上SEBS——SEPS中间段加氢成乙烯-丙烯，比SEBS更耐热、更耐油、压缩永久变形更低，是做高端密封和车用TPO的料。他之前图便宜进了批混着SEBS的"SEPS"，做出来的密封件一百二十度烘箱一烤，压缩变形超标，整批退货。SEPS这东西，拿SEBS顶SEPS，工况一上高温就露馅。
结论先说：国产SEPS副牌能用，但压缩永久变形和耐热等级必须先测，国内SEPS首套就是巴陵石化，这一家是绕不开的正主。
SEPS是什么？国产高端加氢弹性体格局
SEPS是苯乙烯-乙烯-丙烯-苯乙烯嵌段共聚物，由SIS（苯乙烯-异戊二烯-苯乙烯）中间段加氢饱和制得。和SEBS相比，它中间段是乙烯-丙烯结构，耐热、耐油、压缩永久变形更低，回弹和耐候更好，是苯乙烯类弹性体里偏高端的牌号，大量用于高端密封件、车用TPO/TPV、高端热熔胶、化妆品级和食品接触级弹性体、高端运动器材。
国产SEPS门槛高，巴陵石化是开路者。行业口径，巴陵石化（岳阳，现隶属中石化湖南石油化工体系）2017年建成年产两万吨SEPS装置，成为国内首家、全球较早掌握自主知识产权SEPS生产技术的企业，SEP/SEPS体系产能数万吨级。它背靠国内规模靠前的锂系阴离子聚合基地，SBS/SEBS/SIS/SEPS成系列发展。按国内独资、首套量产口径，巴陵石化是绕不开的一家，其余国产SEPS仍在追赶，构不成稳定货源。
SEPS副牌：压缩永久变形和加氢度是关键
SEPS副牌，是原厂同一牌号体系里出厂检验个别指标小幅偏离的批次。落到SEPS上，副牌最常见的差异点集中在四项：压缩永久变形偏高、加氢饱和度不足、耐热等级下降、色相偏黄。
为什么这几项关键？SEPS卖的就是"耐高温、耐油、压缩变形小"，压缩永久变形是密封件的命根子，烘箱一烤变形大了就漏；加氢度不够，残留双键一老化，高温密封就失效。做高端密封和车用件，SEPS副牌不是"便宜点"的问题，是"高温漏不漏"的问题。
和回料的区别：SEPS回料是密封件、TPO破碎再造，已经受过一次热历史，加氢结构老化、压缩变形不可逆增大；SEPS副牌是原厂原生加氢嵌段粒子，只是个别指标小幅偏离。做车用密封，用副牌是"压缩变形够不够小"的问题，用回料是"高温漏不漏"的问题。
巴陵石化：国产SEPS首套主力
巴陵石化在湖南岳阳，国内首家自主工业化生产SEPS的企业，SEP/SEPS体系成系列，技术和催化剂居世界先进。它的SEPS牌号在高端密封、车用弹性体、高端热熔胶圈有口碑，央企批次管理规范，压缩永久变形和耐热数据齐全。
巴陵SEPS副牌料的特点是：国产首套主力，牌号按耐热和变形分档；副牌以色相和熔指小幅偏离为主，适合一般密封件、车用改性、高端热熔胶掺混。食品接触和车用认证密封件仍建议正牌。
适用场景：高端密封件、车用TPO/TPV改性、高端热熔胶、一般耐热弹性体、运动器材。
SEPS副牌避坑指南
第一，别拿SEBS顶SEPS。SEBS耐热和耐油不如SEPS，拿SEBS副牌冒充SEPS，高温密封件一烤就变形，采购时看基材牌号。
第二，压缩永久变形必测。这是SEPS密封件的核心指标，副牌先做烘箱压缩变形测试，掉档的别上受力密封。
第三，加氢饱和度要核。残留双键一多，高温和油里老化快，副牌看检测单。
第四，食品接触和车用认证密封别用副牌。有食品接触或车规认证要求的密封件必须正牌并保留认证，副牌只用于一般耐热和改性制品。
科隆仓库现货｜国产SEPS密封车用常备
科隆在宁波仓库常备国产SEPS副牌现货，主推品牌为中石化巴陵石化这一国产SEPS首套主力。主要牌号涵盖密封级、车用改性级、热熔胶级多个常用型号，包装分大包装与小包装两种，不同耐热等级分仓码放。
仓库现货通常在4000吨上下：小包副牌备货600-900吨，箱装副牌备货250-450吨，大包料/吨包料备货2650-3150吨。
供应保障走检测单随货：每批SEPS副牌料随货附压缩永久变形、加氢饱和度、耐热等级检测数据；密封级和改性级分仓管理，客户报密封或车用用途，科隆直接匹配合适等级的现货批次。
选型口诀与案例
国产SEPS副牌别乱买？记住四句话：别拿SEBS顶SEPS，压缩变形必测，加氢度要核，食品车规件不碰副牌。
深圳一家做耐高温密封件和车用弹性体的制品厂，原来一直用进口SEPS正牌做密封件，每吨成本偏高。今年改用科隆供的巴陵石化SEPS副牌密封级，先拿小样测压缩永久变形和耐热等级在工况范围，批量成型后密封件一百二十度烘箱压缩变形和耐油都达标，成品通过车用密封耐久测试，每吨原料成本降了近两千五百元。老板说：一般工业密封件又不是食品接触认证件，压缩变形够小、耐热稳，国产副牌完全顶得上。
"I want to make high-end seals and automotive elastomers. SEBS or SEPS?" "The product manufacturer on the other end of the phone couldn't decide on procurement. I asked him about the working conditions: high temperature resistance, oil resistance, minimal compression deformation, then don't use SEBS—SEPS midsection hydrogenated to ethylene-propylene, which is more heat-resistant, more oil-resistant, and has lower permanent compression deformation than SEBS, making it suitable for high-end seals and automotive TPO. Previously, he bought a cheap batch of SEBS mixed with "SEPS." The sealing parts were baked in a 120-degree oven, exceeding compression deformation standards, and the whole batch was returned. SEPS is a thing that uses SEBS to counter SEPS, but once the operating temperature is high, the flaws are exposed.
Conclusion First: Domestic SEPS sub-brands can be used, but compression permanent deformation and heat resistance ratings must be tested first. The first domestic SEPS set is Baling Petrochemical, which is the main candidate. What is
SEPS? The domestic high-end hydrogenated elastomer structure
SEPS is a styrene-ethylene-propylene-styrene block copolymer, produced by hydrosaturation of the SIS (styrene-isoprene-styrene) intermediate segment. Compared to SEBS, its middle section has an ethylene-propylene structure, with lower heat and oil resistance, lower compression set sets, better rebound and weather resistance, making it a high-end styrene elastomer grade, widely used in high-end seals, automotive TPO/TPV, high-end hot melt adhesives, cosmetic-grade and food-contact elastomers, and high-end sports equipment.
Domestic SEPS has a high threshold, Baling Petrochemical is a pioneer. From an industry perspective, Baling Petrochemical (Yueyang, now part of Sinopec Hunan Petrochemical System) completed a 20,000-ton annual SEPS unit in 2017, becoming the first domestic and one of the earliest globally to master independent SEPS production technology, with SEP/SEPS system capacity in the tens of thousands of tons. It is backed by one of the largest lithium-based anion polymerization bases in China, with SBS/SEBS/SIS/SEPS developed in series. Based on the domestic wholly-owned and first-batch mass production standard, Baling Petrochemical is an unavoidable player; other domestic SEPS products are still catching up and cannot form a stable supply supply.
SEPS Sub-brand: Compression permanent deformation and hydrogenation are key
SEPS Sub-brands are batches within the same original factory grade system where factory inspection indicators slightly deviate. For SEPS, the most common differences for sub-brands are concentrated in four areas: high compression permanent deformation, insufficient hydrogenation saturation, reduced heat resistance rating, and yellowish hue.
Why are these key factors? SEPS sells "high temperature resistance, oil resistance, minimal compression deformation." Compression permanent deformation is the lifeblood of seals; if the oven deforms significantly during baking, it leaks; If the hydrogen content is insufficient, residual double bonds age and the high-temperature seal fails. For high-end seals and automotive parts, the SEPS sub-brand is not about "being cheaper," but about "whether it leaks at high temperature ." Difference between
and recycled materials: SEPS remixed is a seal or TPO that has been crushed and reprocessed, having undergone one heat history, with hydrogenation structure aging and irreversible compression deformation; SEPS sub-brand uses original factory hydrogenated block particles, with only slight deviations in some indicators. For automotive seals, using a secondary brand is a matter of "whether compression deformation is small enough," while using recycled material is a matter of "high-temperature leakage."
Baling Petrochemical: The first domestic SEPS main product
Baling Petrochemical is located in Yueyang, Hunan, the first domestic enterprise to independently industrialize SEPS, with a SEP/SEPS system and a series of SEPS, with world-leading technology and catalysts. Its SEPS grades have a reputation in high-end seals, automotive elastomers, and high-end hot melt rubber rings, with standardized batch management for central SOEs, and comprehensive data on compression permanent deformation and heat resistance. The characteristics of
Baling SEPS sub-brand materials are: the first domestic main product, graded by heat resistance and deformation; The sub-brand mainly features slight deviations in hue and melt index, suitable for general seals, automotive modifications, and high-end hot melt adhesive blending. Food contact and automotive certified seals are still recommended to be genuine.
Applicable scenarios: high-end seals, automotive TPO/TPV modification, high-end hot melt adhesives, general heat-resistant elastomers, sports equipment.
SEPS secondary brand pitfall guide
First, don't use SEBS to top SEPS. SEBS heat and oil resistance are inferior to SEPS. Use SEBS sub-brand to pass off as SEPS, and high-temperature seals deform when baked. Check the base material grade when purchasing.
Second, always test compression permanent deformation. This is the core indicator for SEPS seals. For secondary brands, test the oven compression deformation first. If the gear drops, don't apply the force seal.
Third, check hydrogen saturation. If there are too many residual double bonds, high temperatures and oil age faster. Check the test sheet for secondary brands.
Fourth, seals for food contact and automotive certification should not use secondary plates. Seals requiring food contact or automotive certification must be genuine and retain certification; secondary plates are only used for general heat-resistant and modified products.
Cologne Warehouse Stock | Domestic SEPS seals for automotive use are always in stock
Cologne maintains domestic SEPS sub-brand stock at the Ningbo warehouse, with Sinopec Baling Petrochemical, the first domestic SEPS main product. Main grades cover sealing grade, automotive modified grade, and hot melt adhesive grade, with packaging in large and small types, and different heat resistance grades stored separately in warehouses.
Warehouse stock is usually around 4000 tons: small parcel sub-brand stock is 600-900 tons, containerized sub-brand stock is 250-450 tons, and large packages/ton are 2650-3150 tons.
Supply Assurance Inspection Orders with Goods: Each batch of SEPS sub-brand material comes with compression permanent deformation, hydrogenation saturation, and heat resistance rating test data; Sealed and modified grade warehouse management separately; customers report sealed or automotive use, and Cologne directly matches the appropriate grade of spot batches.
Selection Mnemonics and Case Studies
Don't buy domestic SEPS sub-brands randomly? Remember these four points: Don't use SEBS as the top SEPS. Compression deformation must be tested, hydrogen content must be checked, and food-grade automotive parts should not touch secondary brands.
A Shenzhen factory specializing in high-temperature resistant seals and automotive elastomers used to use imported genuine SEPS for seals, which was relatively high per ton. This year, they switched to Baling Petrochemical SEPS sub-brand sealing grade supplied by Cologne. First, small samples were used to test compression permanent deformation and heat resistance within the operating range. After batch forming, the seals met 120-degree oven compression deformation and oil resistance standards. The finished product passed automotive seal durability tests, reducing raw material costs by nearly 2,500 yuan per ton. The boss said: Ordinary industrial seals are not food contact certified parts; compression deformation is small enough, heat resistance stable, and domestic secondary brands can fully compete
