说个翻车的事：湖北一家做透明注塑日用品的小厂，图便宜进了一批"国产SAN副牌"，上机注塑透明杯盖，结果一批件里三成发黄、料花，流道里还夹杂未熔透的颗粒。扒开包装一看，牌号标的是透明级，熔指却比配方高出一截。老板这才明白，SAN不是随便哪个厂出的透明颗粒都能顶——熔指和透光率差一点，透明件就露馅。SAN副牌这东西，国内能挑的正主本就不多，选错了厂，整批件都得报废。
结论先说：国产SAN副牌能用，但熔指和透光率必须先测，国内能规模化稳定供货的大陆独资厂，基本就吉林石化这一家正主。今天把吉林石化SAN副牌的门道，一次讲透。
SAN是什么？国产货源为什么集中在一家
SAN是苯乙烯-丙烯腈共聚物，透明、刚性、耐化学、表面硬，比GPPS更耐油耐刮，大量用于一次性打火机、牙刷柄、透明家居件、电池盒、仪表透明罩，也和ABS共混做增韧。它是苯乙烯系里的透明硬料，加工以注塑为主。
国内SAN产能高度集中。行业报告口径，全国SAN年产能约六十余万吨，其中扬子石化—巴斯夫约二十一点五万吨、吉林石化约十七点二万吨、宁波利万（乐金甬兴）约十点六万吨，三家合计占国内产能近七成。但扬子巴斯夫、宁波利万都是合资背景，按"国内=大陆独资"的口径，剔除合资厂后，能规模化、稳定供应国产SAN的独资主力，基本就是中石油吉林石化这一家。宁波乐金甬兴等合资厂的货只能作行业背景，不算国产独资货源。吉林石化本身丙烯腈产能居国内前列，又有ABS装置富余产能可转产SAN，原料和工艺都在自家手里。
SAN副牌：熔指和透光率是两道门
SAN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SAN上，副牌最常见的差异点集中在四项：熔指波动、透光率偏低、黄指偏大、色相偏黄。
为什么这几项关键？SAN做的是透明件，透光率和黄指直接决定产品卖相，黄指一上去，透明杯盖就发乌；熔指波动则影响注塑充模，高熔指副牌做厚件容易飞边、做透明件容易料花。SAN配方是按熔指卡着调的，副牌熔指差一档，注塑温度和射速都得跟着改。
和回料的区别：SAN回料是透明件、牙刷柄边角破碎再造，已经受过一次热历史，透明度和刚性都掉档；SAN副牌是原厂原生聚合颗粒，只是个别指标小幅偏离。做透明日用品，用副牌是"熔指和透光够不够"的问题，用回料是"发黄发雾能不能看"的问题。
吉林石化：国产独资SAN的正主
吉林石化在吉林市，隶属中石油，是国内较早量产SAN的企业之一。它背靠中石油丙烯腈和苯乙烯原料体系，丙烯腈产能居国内前列，又依托自身ABS装置富余能力转产SAN，牌号如SAN-2437等透明注塑级在打火机、透明日用品圈流通多年。它的优势是原料自给、央企批次管理规范，检测记录齐全。
吉林石化副牌料的特点是：牌号以透明注塑级为主，适合打火机、牙刷柄、透明家居件、电池盒等一般透明制品；副牌以熔指和黄指小幅偏离为主，批次管理规范。高端光学级、医疗级透明件仍建议正牌。
适用场景：透明注塑日用品、打火机、牙刷柄、电池盒、一般透明结构件、与ABS共混增韧。
SAN副牌避坑指南
第一，熔指先测再上机。SAN副牌熔指波动比正牌大，换料前先做小试，确认熔指落在配方窗口，别拿高熔指副牌硬做厚壁透明件。
第二，透光率和黄指要看。透明件先核这两项，黄指偏大的批次做出来发乌，别上要求外观的透明罩。
第三，分清国产独资和合资。扬子巴斯夫、乐金甬兴虽是大厂，但属合资货源，跟"国产独资副牌"不是一回事，采购时问清厂和货源归属。
第四，食品接触和光学件别用副牌。有食品接触或光学要求的透明SAN件必须正牌并保留认证，副牌只用于一般透明制品。
科隆仓库现货｜国产SAN透明注塑常备
科隆在宁波仓库常备国产SAN副牌现货，主推品牌为中石油吉林石化这一国内独资主力厂。主要牌号涵盖SAN-2437等透明注塑级常用型号，包装分大包装与小包装两种，按透明日用品配方备货。
仓库现货通常在2000-5000吨：小包副牌备货300-600吨，箱装副牌备货150-300吨，大包料/吨包料备货1500-4100吨。
供应保障走批次留样可溯：每批吉林石化SAN副牌料留样建档，熔指、透光率、黄指检测数据随货同行；客户后续翻旧账，科隆能调出对应批次留样和原始检测记录，问题料可追溯到具体批号。
选型口诀与案例
国产SAN副牌怎么挑？记住四句话：熔指先测再上机，透光黄指要看，独资合资分清楚，光学食品件不碰副牌。
宜昌一家做透明塑料牙刷柄和家居件的注塑厂，原来一直用进口SAN正牌，每吨成本压不下来。今年改用科隆供的吉林石化SAN副牌透明注塑级，先拿两吨小样测熔指和透光率在配方范围，批量上机后透明件外观和刚性都达标，成品通过装配和耐刮测试，每吨原料成本降了近一千三百元。厂长说：牙刷柄又不是光学镜片，熔指够、透光稳，国产独资副牌完全顶得上。
Tell me a mishap: A small factory in Hubei specializing in transparent injection-molded daily necessities bought a batch of "domestic SAN sub-brand" for a bargain price. After machine injection molding of transparent cup lids, 30% of the pieces turned yellow and had unfinished material, and the runner was mixed with unmelted particles. When they opened the packaging, the brand was labeled transparent grade, but the melting finger was a notch higher than the formula. Only then did the boss realize that SAN wasn't just a transparent granule from any factory—if the melting finger and light transmission were slightly lower, the transparent parts would be exposed. There aren't many genuine SAN sub-brands you can choose domestically; if you pick the wrong factory, the whole batch will be scrapped.
Conclusion First: domestic SAN sub-brands can be used, but melting fingers and light transmittance must be tested first. The only wholly-owned mainland manufacturer capable of scalable and stable supply in China is basically Jilin Petrochemical. Today, I'll explain the ins and outs of Jilin Petrochemical's SAN sub-brand all at once. What is
SAN? Why is domestic supply concentrated in one place
SAN It's a styrene-acrylonitrile copolymer, which is transparent, rigid, chemical-resistant, and has a hard surface. It's more oil-resistant and scratch-resistant than GPPS, widely used in disposable lighters, toothbrush handles, transparent home goods, battery boxes, instrument transparent covers, and is also blended with ABS for toughening. It's a transparent hard material in the styrene series, mainly processed by injection molding.
Domestic SAN production capacity is highly concentrated. According to industry reports, the national annual SAN capacity is about 60,000 tons, with Yangzi Petrochemical–BASF about 215,000 tons, Jilin Petrochemical about 172,000 tons, and Ningbo Liwan (Lejin Yongxing) about 106,000 tons, together accounting for nearly 70% of domestic capacity. However, Yangzi BASF and Ningbo Liwan are both joint venture companies. According to the "domestic = mainland wholly owned" basis, excluding joint ventures, the wholly owned main force capable of supplying domestic SAN at scale and stable is basically PetroChina Jilin Petrochemical. Goods from joint ventures like Ningbo Lejin Yongxing can only serve as industry background and do not count as wholly owned domestic goods. Jilin Petrochemical's acrylonitrile capacity ranks among the top domestically, and it has surplus ABS unit capacity to convert to SAN, with raw materials and processes in its own hands.
SAN sub-brand: The melt finger and light transmittance are
SAN two different gates. These are the secondary brands with slight deviations in the factory inspection indicators within the same original grade system. For SAN, the most common differences for secondary brands are concentrated in four areas: melt index fluctuation, lower light transmittance, larger yellow fingers, and yellowish hue.
Why are these key points? SAN makes transparent parts, and light transmittance and yellow fingers directly determine the product's appearance. When the yellow finger is applied, the transparent cup lid turns black; Fluctuating melt fingers affect injection molding, and high-melt index secondary brands tend to burn on thick parts and transparent parts with material distortion. SAN formulas are adjusted according to the melting finger; sub-brands have a melting finger difference of one level, so injection temperature and injection speed must be adjusted accordingly. Difference between
and recycled materials: SAN remixed is made from broken parts and toothbrush handles and corners, having undergone a thermal history and reducing transparency and rigidity; SAN secondary brand is original factory polymer granules, with only slight deviations in some indicators. For transparent daily necessities, using secondary brands is a matter of "melting fingers and light transmission," while using recycled material is a question of "whether yellowing and fogging are readable."
Jilin Petrochemical: The main domestic wholly owned SAN
Jilin Petrochemical is located in Jilin City, affiliated with PetroChina, and is one of the earliest domestic companies to mass-produce SAN. It is backed by PetroChina's acrylonitrile and styrene raw material systems, with acrylonitrile production capacity among the top domestically. It also leverages its own surplus ABS equipment capacity to switch to SAN, with transparent injection-molded grades like SAN-2437 circulating in lighters and transparent daily necessities for many years. Its advantages include self-sufficient raw materials, standardized batch management by central enterprises, and comprehensive testing records. The characteristics of
Jilin Petrochemical sub-brand materials are: mainly transparent injection-molded grade, suitable for lighters, toothbrush handles, transparent household items, battery boxes, and other general transparent products; Sub-brands mainly have slight deviations between melted and yellow fingers, with standardized batch management. High-end optical-grade and medical-grade transparent parts are still recommended to be genuine.
Applicable scenarios: transparent injection-molded daily necessities, lighters, toothbrush handles, battery boxes, general transparent structural parts, and mixing with ABS for toughness.
SAN Secondary Label Pitfall Guide
First, test the melting finger before installing it. SAN secondary brand melt index fluctuates more than genuine brand. Before changing materials, do a small test to confirm the melting finger falls at the formula window. Don't force thick-walled transparent parts with high melting index secondary brands.
Second, check the light transmittance and yellow finger parts. Check these two items first for transparent parts; for batches with yellow fingers that are larger, make them black, and don't use transparent covers that require appearance.
Third, distinguish between domestic wholly foreign-owned and joint ventures. Although Yangtze BASF and Lejin Yongxing are large manufacturers, they are joint venture sources, not the same as "domestic sole proprietorship sub-brands." When purchasing, ask about the factory and the origin of the goods.
Fourth, food contact and optical parts should not use secondary labels. Transparent SAN parts with food contact or optical requirements must be genuine and certified; secondary labels are only used for general transparent products.
Cologne warehouse stock | Domestic SAN transparent injection molding in stock
Cologne maintains domestic SAN sub-brand stock at the Ningbo warehouse, with the main brand being PetroChina Jilin Petrochemical, a wholly-owned domestic leading manufacturer. Main grades cover commonly used transparent injection-molded models such as SAN-2437, with packaging in large and small packaging, prepared according to transparent daily necessities formulas.
warehouse stock is usually between 2000-5000 tons: small sub-brand stocks 300-600 tons, containerized sub-brand stocks 150-300 tons, large packages/ton stocks 1500-4100 tons.
Supply Guarantee Batch Traceability: Each batch of Jilin Petrochemical SAN sub-brand material is archived and recorded, with melting finger, light transmittance, and yellow finger test data carried along with the goods; Customers later review old issues, and Cologne can retrieve the corresponding batch retained samples and original inspection records, with problematic materials traceable back to the specific batch number.
Selection Mnemonics and Cases
How to Choose Domestic SAN Sub-Brand? Remember these four points: test the melting index before machine installation; check the transparent yellow finger; distinguish wholly-owned and joint ventures; optical food parts don't touch secondary brands.
Yichang is an injection molding factory that makes transparent plastic toothbrush handles and household parts. They used to use imported SAN brand, but the cost per ton couldn't be lowered. This year, they switched to using Jilin Petrochemical SAN sub-brand transparent injection molding grade supplied by Cologne. They first tested the melt index and light transmittance within the formula range using two tons of samples. After batch production, the transparent parts met the appearance and rigidity standards, and the finished products passed assembly and scratch resistance tests, reducing raw material costs by nearly 1,300 yuan per ton. The factory director said: Toothbrush handles aren't optical lenses; melting fingers are sufficient and light transmission stable. Domestic wholly owned secondary brands can fully compete
