LDPE副牌市场，最乱的不是价格，是身份
东莞一家做包装膜的厂老板跟我吐槽，去年在市场上收了几批"LDPE副牌"，价格确实比正牌低一截，可拉回来一上机，晶点忽多忽少，膜面时而发亮时而发乌。一问卖家，说是"大厂副牌"，再追问是哪家、哪个牌号，对方就开始打太极。最后查了一圈，根本分不清是燕山的过渡料还是杂牌回掺。
LDPE（低密度聚乙烯）这个圈子，最乱的从来不是价格，是身份。包装膜、农膜、复合膜都用它，正牌贵，国产副牌本来是条路，可货源一杂，谁都敢说自己是"大厂副牌"。中石化、中石油，再加一个合资背景的上海赛科，这三家是国产LDPE的主流货源，这篇把水搅清楚。
国产LDPE格局：两桶油占主导，合资补一块
LDPE是高压法生产的低密度聚乙烯，透明度、柔软性、热封性好，做薄膜、涂层、电缆绝缘都离不开。国内LDPE产能约400万至420万吨/年，装置集中度相当高。
中石化系统拥有多套LDPE装置，总产能约160万至168万吨/年，占全国约四成，燕山、扬子、茂名、镇海都是主力；中石油系统有大庆、兰州、独山子等装置，总产能约60万至88万吨/年；上海赛科是中石化与BP各持股50%的合资企业，也有LDPE装置（合资背景，文中标注）。这三家，构成了国产LDPE的主流货源。
LDPE副牌的晶点，就是行业乱象的重灾区
LDPE副牌的概念和其他聚烯烃一样：同一装置同一牌号，出厂检验个别指标——熔指、晶点、透明度、色相——小幅偏离正牌标准。来源是开停车头尾料、牌号切换过渡料、工艺波动批次。仍是原生聚合粒子。
但LDPE副牌有个特殊性：晶点和透明度是它容易出问题的指标。做膜的厂都知道，晶点多了，膜面就有亮点，印刷和热封都受影响。市场上的乱象，就是把晶点偏多、透明度不够的过渡料，包装成"大厂副牌"往外甩。分清四层：正牌全指标达标；副牌基材一致、个别指标略偏；回料受过一次热历史；再生料性能波动大。LDPE副牌价格通常低于正牌，适合非透明膜、一般涂层、内包装这类对透明度要求不高的场景。
中石化LDPE：薄膜老牌户，牌号熟路子正
中石化是国内LDPE产能规模领先的企业，燕山、茂名、扬子、镇海都有装置。代表牌号如18D是燕山的老牌薄膜料，2426H是茂名/燕山常用的薄膜/涂层料，LD165也有稳定市场。
中石化LDPE副牌的特点，是装置老、牌号熟，副牌主要来自过渡料和波动批次。做膜的厂对2426H、18D这些牌号都熟，副牌的晶点和熔指波动相对可预期。适合做非透明包装膜、一般复合膜、涂层料。要注意的是，做透明膜和高端印刷膜，副牌晶点风险大，得谨慎。
中石油LDPE：西北农膜电缆料有底子
中石油LDPE依托大庆、兰州、独山子等装置，总产能约60万吨/年。代表牌号如2426H（大庆）、112A等，在农膜和电缆绝缘领域有积累。
中石油LDPE副牌的特点，是西北装置开车率稳，副牌货源以农膜和电缆绝缘过渡批次为主。适合农膜、一般包装膜、电缆料这类对透明度要求不高的场景。因为成本结构有优势，它的副牌价格带往往有竞争力。
上海赛科LDPE：合资背景，货源要单独看
上海赛科石油化工是中石化与BP各持股50%的合资企业，坐落上海漕泾，有乙烯、PE等装置。它的LDPE属于合资货源，不是纯内资，但装置技术和管理偏向合资标准。
上海赛科LDPE副牌的特点，是合资装置工艺控制细，副牌指标偏离幅度通常较小，但因为合资背景，货源流通量不如两桶油那么大。对做中高端薄膜、对外观有一定要求的下游，赛科副牌在指标稳定性上有自己的位置。采购时要认准合资身份，别和纯内资货源混为一谈。
国产LDPE副牌，先测后签才不踩坑
一是先测晶点和透明度。LDPE副牌容易出问题的就是晶点，进厂先看晶点数量和分布。二是，先测熔指。做膜对熔指敏感，熔指偏了，膜厚薄均匀度就变。三是，先测后签。要随货检测单，先小样上机，过了再签合同。东莞那个厂的教训，就是没测晶点、没留小样，出了问题连货是哪来的都说不清。
科隆仓库现货｜国产LDPE现货实拍
做国产LDPE副牌，现货看得住才敢用。科隆仓库常备国产LDPE现货，主推中石化、中石油、上海赛科三家品牌。
• 主推品牌：中石化、中石油、上海赛科（合资货源）
• 主要牌号：18D、2426H、LD165、112A等常用牌号
• 包装规格：大包装、小包装都有
• 仓库现货：通常在5000吨左右
• 小包副牌备货800-1000吨、箱装副牌备货300-500吨、大包料/吨包料备货3500-3900吨
• 供应保障：先测后签
大包料、吨包料适合连续生产的膜厂，小包副牌和箱装副牌适合中小厂试机和补单，按需调度。
选型口诀加一个真实案例
国产LDPE副牌选型，记住三句话：先测晶点、先测熔指、先测后签。别光看报价单上的数字，把晶点和熔指对上，省下来的才是真钱。
接着说东莞那个厂。后来他们改用中石化2426H副牌，要求随货检测单，进厂先测晶点和熔指，小样上机试膜，晶点分布在非透明膜可接受范围，熔指在工艺窗口内。正式投产后，膜面晶点问题没再出现，良率稳定在96%以上，单吨成本比正牌降了约550元。差别不在料多神，而在测了晶点、留了小样。
LDPE sub-brand market, the most chaotic thing isn't the price, but the identity
A factory owner in Dongguan who makes packaging film complained to me that last year I bought several batches of "LDPE sub-brand" at the market, and the price was indeed lower than the genuine brand, but once I put it back on the machine, the crystal dots fluctuated, and the film surface fluctuated between shiny and dark. When I asked the seller, they said it was a "big factory sub-brand," and when I asked which brand and brand it was, they started playing the Tai Chi game. After a thorough investigation, I couldn't tell if it was a transition material from Yanshan or mixed in with a generic brand.
LDPE (low-density polyethylene) circle, the most chaotic thing has never been the price, but the identity. Packaging film, agricultural film, and composite film all use it. Genuine brands are expensive, and domestic sub-brands are originally a path, but with mixed supply, anyone dares to call themselves a "big factory sub-brand." Sinopec, PetroChina, and a joint venture with Shanghai Saike—these three are the mainstream sources for domestic LDPE. This article clarifies the waters.
Domestic LDPE Landscape: Two oil giants dominate, joint ventures add one
LDPE low-density polyethylene produced by the high-pressure process, which has good transparency, flexibility, and heat sealability, making films, coatings, and cable insulation indispensable. Domestic LDPE production capacity is about 4 million to 4.2 million tons per year, with a high concentration of units.
Sinopec System owns multiple LDPE units, with a total capacity of about 1.6 to 1.68 million tons per year, accounting for about 40% of the national total, with Yanshan, Yanzi, Maoming, and Zhenhai as main producers; PetroChina Systems has units in Daqing, Lanzhou, and Dushanzi, with total capacity of about 600,000 to 880,000 tons per year; Shanghai SECCO is a joint venture with Sinopec and BP each holding 50%, and also has LDPE units (joint venture background, noted in the article). These three make up the mainstream sources of domestic LDPE products.
LDPE sub-brand's crystal dots are the epicenter of industry chaos
LDPE The concept of sub-brands is the same as other polyolefins: same device and same grade, but individual factory inspection indicators—melting finger, crystal point, transparency, hue—slightly deviate from genuine standards. Sources include start-stop and stop-end materials, grade switching transition materials, and process fluctuation batches. Still native polymer particles.
But LDPE sub-brands have a special feature: crystal dots and transparency are the indicators where they are prone to problems. Manufacturers making films know that when there are more crystal dots, the film surface has bright spots, affecting printing and heat sealing. The market chaos is that transition materials with too many crystalline dots and insufficient transparency are packaged as "big factory sub-brands" and thrown out. Four layers are clear: genuine products meet all standards; Sub-brand base materials are consistent, with some indicators slightly off-limits; Re-imported materials have undergone one thermal history; Recycled materials have significant performance fluctuations. LDPE sub-brand prices are usually lower than genuine brands, suitable for non-transparent films, general coatings, and inner packaging scenarios where transparency is not required.
Sinopec LDPE: A long-established film brand, with well-established grades
Sinopec is a leading domestic LDPE production capacity, with facilities in Yanshan, Maoming, Yanzi, and Zhenhai. Representative grades include 18D is Yanshan's established film material, 2426H is a commonly used film/coating material in Maoming/Yanshan, and LD165 also has a stable market. The characteristics of
Sinopec LDPE sub-brand are old equipment and well-known grades, with sub-brands mainly coming from transition materials and fluctuating batches. Manufacturers familiar with films like 2426H and 18D grades, so fluctuations in the crystal dot and melting index of the sub-brand are relatively predictable. Suitable for non-transparent packaging films, general composite films, and coating materials. Note that for transparent films and high-end printing films, sub-brands carry high crystal point risks and must be cautious.
PetroChina LDPE: Northwest agricultural film cable materials have a solid foundation
PetroChina LDPE relies on Daqing, Lanzhou, Dushanzi, and other units, with a total capacity of about 600,000 tons per year. Representative grades include 2426H (Daqing), 112A, etc., with accumulated experience in agricultural film and cable insulation. The characteristic of
PetroChina LDPE sub-brands is the stable operating rate of Northwest units, with sub-brand supply mainly being transitional batches of agricultural film and cable insulation. Suitable for agricultural films, general packaging films, cable materials, and other scenarios where transparency is not required. Due to cost structure advantages, its sub-brand price range is often competitive.
Shanghai Saike LDPE: Joint venture background, supply sources need to be viewed separately
Shanghai Saike Petrochemical is a joint venture with Sinopec and BP each holding 50%, located in Caojing, Shanghai, with ethylene, PE, and other equipment. Its LDPE is a joint venture source, not purely domestic, but its equipment technology and management lean toward joint venture standards. The characteristic of the
Shanghai Saike LDPE sub-brand is its fine process control for joint venture units, with usually small deviations in sub-brand indicators, but due to the joint venture background, the circulation volume of supply is not as large as that of two oil companies. For downstream companies producing mid-to-high-end films with certain appearance requirements, Saike's sub-brand has its own position in indicator stability. When purchasing, make sure to be a joint venture and don't confuse it with pure domestic sources.
For domestic LDPE sub-brands, test before signing to avoid pitfalls
First, test the crystal dot and transparency first. The most common problem with LDPE sub-brands is the crystal dots; when entering the factory, check the number and distribution of crystal dots. Second, first test the melt finger. The film is sensitive to melt fingers; if the melt finger is off, the uniformity of film thickness changes. Third, test before signing. You need to test the sample with the goods, first put the sample on the machine, and only sign the contract after it's passed. The lesson from that factory in Dongguan was that if they didn't measure the crystal point or leave samples, if something went wrong, they couldn't even tell where the goods came from.
Cologne warehouse spot | Domestic LDPE spot actual photos
Domestic LDPE sub-brand, only use it if you can keep track of the stock. Cologne warehouse always stocks domestic LDPE stock, mainly promoting Sinopec, PetroChina, and Shanghai SECCO.
• Main Brands: Sinopec, PetroChina, Shanghai Saike (joint venture source)
• Main Grades: 18D, 2426H, LD165, 112A and other commonly used grades
• Packaging Specifications: Both large and small packages available
• Warehouse Stock: Usually around 5,000 tons
• Small sub-brand stock: 800-1,000 tons, Containerized sub-brand stock 300-500 tons, large packaged material / ton packaging stock stock 3500-3900 tons
• Supply guarantee: test before signing
Large package materials and ton package materials are suitable for continuous production film factories; small package sub-brands and boxed sub-brands are suitable for small and medium factories to test machines and supplement orders, with scheduling as needed.
Selection tip plus a real case
Domestic LDPE secondary brand selection, remember these three points: test the crystal dot first, test the melt index first, test before signing. Don't just look at the numbers on the quotation; match the crystal dot and melt finger to save real money.
continuing to talk about the Dongguan factory. Later, they switched to Sinopec 2426H secondary brand, requiring inspection orders with the goods: upon arrival, the crystal dots and melting fingers were tested, the samples were put on the machine for film testing, the crystal dots were distributed within the acceptable range of non-transparent films, and the melt fingers were within the process window. After official production, the crystal dot problem on the film surface no longer appeared, yield remained stable above 96%, and the cost per ton was about 550 yuan lower than the genuine brand. The difference wasn't in the amount of material, but in measuring the crystal dots and leaving samples.
