一吨CAP正牌省三百块，一批包装膜漏氧、阻隔不达标，赔出去的是五千。
这笔账小学生都会算，但下单的时候总有人先盯着那一吨省的三百块，把后面那五千忘了。
CAP这东西，正牌贵，回料不敢用，副牌又怕阻隔性不达标——做阻隔膜的采购，每年都在这三角里来回拉扯。
说白了，CAP不是什么热门明星材料，但它在食品包装和涂层里干的是"挡气挡味"的细活。这篇把CAP副牌的成本账算明白。
CAP比CA更透，比CAB更硬
CAP学名醋酸丙酸纤维素，是纤维素酯化时用丙酸把一部分羟基换成丙酸酯基的产物。
纤维素三家得分清：CA是醋酸酯基为主，硬、做镜架；CAB是醋酸加丁酸酯基，柔韧、做涂料；CAP是醋酸加丙酸酯基，透光更好、硬度适中、阻隔性不错，做透明包装和涂层正合适。
它能干什么？食品包装阻隔膜、卷烟包装涂层、眼镜镜片涂层、医疗器械外壳、笔杆和工具手柄。
全球格局。按产能和市场份额口径，国外前三家：
第一梯队是美国伊士曼（Eastman），CAP系列的主力供应商，在透明包装和涂层领域份额领先。
第二梯队是日本大赛璐（Daicel），在高纯醋酸丙酸纤维素上有积累。
第三梯队是日本三菱化学（Mitsubishi Chemical），走综合化工配套路线。
这三家加起来占了全球CAP产能的六成上下，集中度不低。
副牌不是降级，是丙酰基化验单上贴了边
CAP副牌怎么来？定义照旧：同一厂家同一牌号，出厂检验个别指标没完全踩线，合格的贴正牌，没完全达标的就是副牌。原厂原生粒子。
四大来源：开停车头尾料、牌号切换过渡料、工艺波动致丙酰基含量或透光率小幅超标的批次、副线尾料。
| 类型 | 来源 | 品质 | 典型用途 |
|---|
| 正牌 | 原厂达标批次 | 全指标达标、批次稳 | 高阻隔食品包装、认证件 |
| 副牌 | 原厂未达标批次 | 个别指标小幅偏离，基材与正牌一致 | 一般包装膜、涂层、手柄 |
| 回料/水口料 | 加工边角料再造粒 | 已受过一次热历史 | 低要求制品 |
| 再生料 | 废旧塑料回收造粒 | 性能波动大 | 低端填充 |
CAP的关键指标是丙酰基含量和透光率，副牌往往就差在这两项。
伊士曼CAP，透明包装那条线的主力
先说伊士曼。它的CAP系列在透明包装和涂层里用得最多。
它的优势是透光率高、跟增塑剂相容好、热封性稳定。食品包装膜和镜片涂层是它的主场。
它的副牌长什么样？多数是透光率差零点几个百分点、或者丙酰基含量小幅贴线的料。分子结构没换，吹出来的膜透明度和阻隔性跟正牌基本一档，但做高阻隔认证包装就剔出来了。
用在哪？一般包装膜、普通涂层、笔杆工具手柄。这些场合对透光和阻隔的要求没到顶，副牌顶得住。
大赛璐，高纯涂层那一档
再说日本大赛璐。它的CAP走高纯路线。
高纯级CAP在镜片涂层、特殊包装涂层里用得多，对残留和杂质控制严。它的副牌，常见是灰分或透光贴线的批次。
用在哪？普通涂层、一般包装。碰到大赛璐副牌，注意它的纯度偏光学级，用在普通包装上算高射炮打蚊子，但性价比划算。
三菱化学，综合配套里的稳妥派
第三家是日本三菱化学。它的CAP走综合配套路线，跟它的其他纤维素酯和光学材料协同。
它的副牌多为配套特定客户规格时的过渡料，或者丙酰基含量贴在临界值的批次。
用在哪？一般包装膜、工业涂层。三菱的副牌流通量不算大，但碰到对路的规格，批次稳定性不错，适合跟一个长期规格跟下来。
顺带把纤维素三家再拎清楚一遍，免得下单时张冠李戴：CA硬、做镜架和片基；CAB柔韧、做涂料油墨；CAP透光、做透明包装和涂层。三个都叫"醋酸纤维素"系，但酯基不一样、溶剂体系不一样、成型工艺也不一样。拿CAP去做涂料，流平不对；拿CAB去吹包装膜，阻隔不够。牌号认准丙酰基含量那一行，别只看袋子上的"醋酸纤维素"五个字。
CAP副牌是正牌这出戏里没领主角证的配角
CAP副牌怎么挑？几笔实在账。
第一，先对透光和阻隔。CAP副牌最常翻车的就是透光率飘——吹出来的膜雾度大，客户一眼看穿。进厂先测透光率和氧气透过量，这两项对上再谈。
第二，算用途账。高阻隔食品包装、认证件上正牌；一般包装膜、普通涂层、笔杆手柄，副牌够用。别拿副牌怼食品认证包装。
第三，先吹膜小试。CAP成膜性挑工艺，副牌换批次先吹一米看雾度和热封，没问题再放量。冬天车间温度低的时候，CAP膜容易发脆断膜，别光看室温配方，试机时把车间实际温度也考虑进去。
西宁有家做食品阻隔包装膜的客户，之前图便宜上了批CAP副牌，结果膜的氧气透过量比标准高了一截，装坚果一个月就氧化哈败，一批货退货。后来换成伊士曼同牌号副牌，每批先吹膜测透过量，氧化投诉从9%降到0.6%。
科隆仓库现货｜CAP补货
主推品牌：美国伊士曼Eastman、日本大赛璐Daicel、日本三菱化学。
主要牌号：Eastman CAP系列。
包装规格：大包装、小包装都有，小包装试机打样，大包装、吨包料量产摊薄。
仓库现货：CAP副牌仓库现货通常在4000吨上下，常年备货不断档。
其中小包副牌备货600-900吨、箱装副牌备货250-450吨、大包料/吨包料备货2650-3150吨，按订单配比灵活出。
供应保障：检测单随货走，每批指标可核。
六句口诀，CAP副牌算账不亏
高阻隔食品认证包装——正牌，别省；
一般包装膜、普通涂层——副牌可用，先测透光；
要高纯涂层——看大赛璐；
要批次稳——三菱化学路线可试；
换批次先吹膜看雾度热封；
别拿副牌怼食品阻隔认证件。
CAP这材料，不挑事但也不扛事。选对副牌，一卷膜的成本能压一截；选错了阻隔性，一整批哈败的货够你赔到心疼。
Saving 300 yuan per ton of genuine CAP, but losing 5,000 yuan on a batch of packaging film leaking oxygen or substandard barrier content.
Even elementary school students can calculate this amount, but when ordering, some people focus on saving 300 yuan per ton and forget about the 5,000 yuan afterward.
CAP this thing, genuine brands are expensive, recycled materials are hesitant to use, and secondary brands worry about poor barrier performance—procurement for barrier films is a back-and-forth every year.
To put it bluntly, CAP isn't a popular star material, but it does the meticulous work of "blocking air and odor" in food packaging and coatings. This article clearly calculates the cost accounts of CAP secondary brands.
CAP is more transparent than CA and harder than CA
CAP Scientific name is cellulose acetate propionate, which is produced by replacing part of the hydroxyl group with propionate in cellulose during esterification.
Cellulose is divided among the three companies: CA is mainly acetate-based, hard, and used for frames; CAB is acetate combined with butyrate-based, flexible, and used for coatings; CAP is acetate plus propionate group, offering better light transmission, moderate hardness, and good barrier properties, making it ideal for transparent packaging and coatings.
What can it do? Food packaging barrier films, cigarette packaging coatings, eyeglass lens coatings, medical device casings, pen barrels, and tool handles.
Global Landscape. By capacity and market share, the top three foreign companies are:
The first tier is Eastman from the US, a main supplier of CAP series and leading in the transparent packaging and coating sectors.
The second tier is Japan's Daicel, which has accumulated experience in high-purity cellulose acetate propionate.
The third tier is Mitsubishi Chemical of Japan, which follows a comprehensive chemical supply route.
Together, these three companies account for about 60% of global CAP capacity, with a high concentration level.
The secondary brand is not a downgrade; it's the propionyl test report with a side
CAP attached . How is the secondary brand produced? Definition as usual: Same manufacturer, same grade; if some factory inspection indicators do not fully meet the standards, those that pass are labeled as genuine; those that do not fully meet the standards are secondary brands. Original factory original particles.
Four major sources: starting and stopping the initial and tail materials, grade switching transition materials, batch of propionyl content or light transmittance slightly exceeding standards due to process fluctuations, and secondary line residue.
| Type | Source | Quality | Typical Uses |
|---|
| Genuine Brand | Original Factory Standard Batch | All Indicators Compliant, Batch Stable | High Barrier Food Packaging, Certified Parts |
| Subbrand | Original factory non-compliant batch | Slight deviations in some indicators, base material consistent with genuine brand | General packaging film, coating, handles |
| Recycled material/sprue material | Processed scrap re-pelletizing | Already experienced once heat history | Low requirements products |
| Recycled material | Recycled Plastic Pelletizing | Significant Performance Fluctuations | Low-End Filler |
CAP The key indicators are propionyl content and light transmittance; sub-brands often fall short in these two aspects.
Eastman CAP, the main product in the transparent packaging line
Let's start with Eastman. Its CAP series is most commonly used in transparent packaging and coatings.
Its advantages are high light transmittance, good compatibility with plasticizers, and stable heat sealability. Food packaging films and lens coatings are its main fields.
What does its secondary label look like? Most have light transmittance differing by a few tens of percent, or materials with a small propionyl content and slightly lined lines. The molecular structure remains unchanged, so the transparency and barrier properties of the blown film are basically on par with genuine brands, but with high-barrier certification packaging, it stands out.
Where is it used? General packaging films, regular coatings, pen barrel and tool handles. In these cases, the requirements for light transmission and blocking aren't maxed, but the secondary card can handle it.
Grand Cellu, the high-purity coating grade
Now, let's talk about the Japanese Grand Cellu. Its CAP follows the high-purity route.
High-purity CAP is used extensively in lens coatings and special packaging coatings, with strict control over residues and impurities. Its secondary cards are commonly used for ash or translucent line markings.
Where is it used? Ordinary coatings, general packaging. When dealing with Grand Cellul secondary cards, pay attention to its optical purity grade; using it on regular packaging is like a high-altitude cannon to kill mosquitoes, but it's cost-effective.
Mitsubishi Chemical, the steady side among comprehensive suppliers.
The third is Japan's Mitsubishi Chemical. Its CAP takes a comprehensive supply route, collaborating with other cellulose esters and optical materials.
Its sub-brands are mostly transition materials for specific customer specifications, or batches with propionyl content labeled at critical values.
Where is it used? Generally, packaging films and industrial coatings. Mitsubishi's secondary brands don't have a large circulation, but when they meet the right specifications, batch stability is good, making them suitable for long-term compliance.
Also, clarify the three cellulose brands again to avoid confusing them when placing orders: CA is hard, used for frames and film bases; CAB is flexible, used for coating inks; CAP is translucent and makes transparent packaging and coatings. All three are called "cellulose acetate" series, but their ester bases, solvent systems, and molding processes are also different. Using CAP for coatings results in incorrect leveling; Using CAB to blow on packaging film results in insufficient barriers. Focus on the propionyl content of the grade; don't just look at the words "cellulose acetate" on the bag.
CAP sub-brand is the genuine brand. How do you choose the supporting role in this drama without a main
CAP license? A few real accounts.
First, start with light transmission and blocking. The most common mishap with CAP sub-brands is floating light transmittance—the blown film is highly hazy, which customers can see through at a glance. Before entering the factory, measure light transmittance and oxygen permeability; compare these two before discussing.
Second, calculate the usage account. High-barrier food packaging and certified parts must be certified with official labels; General packaging film, standard coatings, pen handles—secondary brands are sufficient. Don't use secondary brands to challenge food certification packaging.
Third, first test the film by blowing the film. Choose the CAP film-forming process; when switching batches for secondary brands, blow one meter first to check haze and heat sealing, then increase volume. In winter, when workshop temperatures are low, CAP film tends to become brittle and break. Don't just look at the room-temperature formula; consider the actual workshop temperature during testing.
Xining has a client who makes food barrier packaging films. Previously, they bought a batch of CAP sub-brands at a low price, but the film's oxygen penetration was higher than the standard. After a month of nuts, it oxidized and spoiled, and a batch was returned. Later, they switched to Eastman sub-brands of the same grade, blowing film to measure permeability per batch, reducing oxidation complaints from 9% to 0.6%.
Cologne warehouse in-stock | CAP restocking
Main brands: Eastman (USA), Daicel (Japan), Mitsubishi Chemical (Japan).
Main grade: Eastman CAP series.
Packaging specifications: Both large and small packages, small packaging for trial machine testing, large packaging and mass production and thinning per ton.
Warehouse Stock: CAP sub-brand warehouse stock is usually around 4000 tons, with year-round stock never stalled.
Of these, small sub-brand stocks are 600-900 tons, sub-brand containerized stocks are 250-450 tons, and large packages/ton are 2650-3150 tons, with flexible distribution based on order ratios.
Supply Assurance: Test orders are sent with the goods, and each batch can be verified as a target.
Six mnemonics, CAP sub-brand accounts are never a loss .
High-barrier food certified packaging—genuine brand, don't save money;
General packaging film, regular coating — secondary brands can be used, test light transmittance first;
For high-purity coatings — check with the competition Lu;
For stable batches — Mitsubishi Chemical route can be tried;
When switching batches, first blow film to check haze and heat sealing;
Don't use secondary brands to meet food barrier certification requirements.
CAP materials, they don't pick fights but also can't handle stress. Choosing the right secondary brand can cut the cost of a roll of film by a portion; choosing the wrong one for barrier properties, a whole batch of defective goods can cost you dearly.
