“这壳子怎么发黄发黏了？”“套上没俩礼拜就黄得像旧手机，还黏指纹。”“摔一次边角就裂，这料不是说抗摔吗？”
做手机保护套的厂，老板和采购在样品架前就这么吵起来了。采购说料是按TPU买的，老板说这TPU怎么一碰就露馅。一圈下来才发现：便宜那一柜，是聚酯型当聚醚型卖， aliphatic（脂肪族）当芳香族卖，做出来的壳不黄变才怪。
本质上，TPU是个体系极多、门道极深的料。聚酯、聚醚、脂肪族、芳香族，硬度从60A到75D，做手机壳、做管材、做线缆、做鞋，完全是不同的料。今天就把TPU全球前三的国外大厂讲清楚，顺便说透副牌在3C保护套上怎么用才不黄、不黏、不裂。
TPU是什么，一个被硬度和体系区分的世界
TPU，热塑性聚氨酯，由异氰酸酯、多元醇和扩链剂做出来的弹性体。它又韧又耐磨、回弹性好、可热塑加工。但TPU是个大家族：聚酯型耐油耐磨但易水解，聚醚型耐水解耐低温，芳香族强度高但易黄变，脂肪族不黄变贵一截。做手机透明壳，体系选错，黄变和发黏就一起来。
全球TPU玩家不少，但高端牌号集中在几家国外大厂。按市场份额与产能口径，综合行业研报与企业公开资料（2025—2026年）：
1. 巴斯夫 BASF（德国）：Elastollan® 品牌，份额约15%上下，硬度牌号从60A到75D覆盖全；
2. 科思创 Covestro（德国）：Desmopan® 品牌，份额约13%—20%，芳香族/脂肪族齐全；
3. 路博润 Lubrizol（美国）：Estane® 品牌，TPU梯队玩家，薄膜、3C、线缆应用见长。
这三家加上亨斯迈等，把高端TPU的主要份额攥在手里。做3C透明壳要的不黄变、高透、抗摔，恰恰是这几家脂肪族和透明牌号的强项。
TPU副牌从哪来，和再生料差在哪
副牌逻辑不变：同一装置、同一批聚合料，全指标达标贴正牌，个别指标小幅没踩线就是副牌。TPU副牌身上常见的问题，是硬度小幅偏离、熔指/流动略变、透明件黄度指数略高。
四个来源：开停车头尾料、切牌号过渡料、工艺波动导致单项指标小幅超标的批次、副线尾料。它是原厂原生TPU粒子，分子结构和正牌一致。
边界这里格外坑：TPU副牌是原厂原生料；而再生TPU、杂色回收料，黄变、发黏、性能波动都来得快。做透明手机壳，把再生料当副牌，上手俩礼拜就黄得没法看。还有一条：聚酯型和聚醚型别搞混，水解环境用聚酯型，半年就水解发黏。做3C保护套的，把正牌/副牌/回料/再生料分清楚，再把体系选对，是基本功。包装认准大包装、小包装即可。
巴斯夫Elastollan®：硬度全覆盖的老牌
先看巴斯夫。德国巴斯夫，Elastollan®是它家TPU的招牌，从60A软到75D硬，聚酯、聚醚、聚己内酯体系齐全，还有耐UV、阻燃、防静电、食品接触级。做汽车、鞋材、工业件，Elastollan®是老手。
Elastollan®副牌，多为硬度或流动小幅偏离的批次。它适合做非透明、非苛刻黄变要求的结构件、护套、一般保护套。但做高透不黄变的手机壳主面，得用它的脂肪族透明正牌，副牌只敢用在非主面、内衬、配色件上。
科思创Desmopan®：透明与不黄变派
再看科思创。德国科思创，Desmopan®是它家TPU品牌，芳香族、脂肪族产品线齐全，脂肪族不黄变牌号在透明3C、户外件上很受认可。它在透明、耐水解、回弹性上口碑在线。
Desmopan®副牌，适合做对透明要求中等、不做长期户外暴晒的一般保护套、内衬件。做长期户外、做主展示面透明壳的，脂肪族正牌别省。它的副牌拿来做内衬、按键、包边件，性价比可观。
路博润Estane®：薄膜与3C精工派
再看路博润。美国路博润的Estane® TPU，在薄膜、3C、线缆、胶粘剂应用上见长，牌号细、性能稳。它走的是精细应用路线，做高透、手感、耐磨的小件很对口。
Estane®副牌，适合做非主展示面的3C配件、包边、内衬件，对手感和耐磨要求中等的场景。它的量没有巴斯夫那么大，但挑出来的精选副牌，用在手机壳的辅助件上很稳。做主面透明不黄变壳的，正牌还是别省。
TPU副牌怎么选，手机壳厂的三道关
做3C保护套用TPU副牌，三道关要过。
头一关，选体系。要透明不黄变，走脂肪族；要耐水解耐低温，走聚醚；要耐磨耐油，才用聚酯。体系选错，再便宜的料也是废。第二关，测黄度和硬度。副牌进厂，做黄变指数、硬度、耐磨测试，透明壳主面别用黄度偏高的副牌。第三关，分用途。主展示面透明壳走正牌脂肪族，副牌只用在内衬、包边、非主面。
常见坑：拿聚酯型当聚醚型，夏天水解发黏；拿芳香族当脂肪族，俩礼拜黄透；拿再生料当副牌，手感发黏还掉粉。做手机壳的都知道，一个壳黄了、黏了，客户退的不是这一个壳，是整个品牌的口碑。
科隆仓库现货｜TPU打样
主推品牌：巴斯夫、科思创、路博润
主要牌号：Elastollan系列、Desmopan系列、Estane系列
包装规格：大包装/小包装均有备货
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：检测单随货
TPU副牌选型口诀
给3C配件厂一套：
1. 主面透明不黄变壳——脂肪族正牌别省；
2. 内衬、包边、非主面件——副牌可用；
3. 认厂：Elastollan®、Desmopan®、Estane®，原厂原包；
4. 选体系：透明不黄变走脂肪族，耐水解走聚醚；
5. 进厂测黄度、硬度、耐磨，三项过关再签；
6. 别拿聚酯型冒充聚醚型，夏天水解发黏；
7. 别拿再生料当副牌，手感掉粉快。
烟台有家做手机保护套的厂，之前为压成本，进了一柜便宜的“透明TPU副牌”，上手才发现是芳香族冒充脂肪族，客户套上手机俩礼拜，壳就黄得像放了一年，还黏指纹，退货率冲到16%。后来我们给它配了科思创Desmopan®和巴斯夫Elastollan®的精选副牌，只用于内衬和包边，主面透明壳仍走脂肪族正牌，黄变和发黏的退货从16%压到0.6%。
这就是TPU选型的分寸——做3C透明件，拼的是不黄变、不发黏的口碑，副牌能省的是辅助件的钱，省不了主面的口碑。宁波市科隆新材料有限公司做进口大厂副牌多年，帮3C配件厂把副牌摆在非主面件上，正牌守住透明不黄变这条线，一年下来省下的退换货钱，比料钱差价多得多。
"Why is this shell yellow and sticky?" "After just two weeks of wearing the case, it turned yellow like an old phone and even stuck fingerprints." "The edges crack after one drop. Isn't this material supposed to be drop-resistant?"
The factory that makes phone protective cases had a heated argument with the buyer in front of the sample rack. The buyer said the material was bought according to TPU, but the boss said TPU was exposed at the slightest touch. After a round of inspection, they realized: the cheaper cabinet sold polyester as polyether type, and aliphatic (aliphatic) as aromatic type. The finished case would turn yellow.
Essentially, TPU is a material with many systems and deep nuances. Polyester, polyether, aliphatic, aromatic polyester, with hardness ranging from 60A to 75D, used for phone cases, tubes, cables, shoes—these are completely different materials. Today, let's clearly explain the top three TPU manufacturers worldwide, and explain how secondary brands are used on 3C protective cases to prevent yellowing, sticking, and cracking. What is
TPU? A world
TPU distinguished by hardness and system : thermoplastic polyurethane, an elastomer made from isocyanates, polyols, and chain extenders. It is tough, wear-resistant, highly resilient, and thermoplastic. But TPU is a big family: polyester is oil-resistant and wear-resistant but easily hydrolyzed; polyether type is hydrolyzable and low-temperature resistant; aromatic type is strong but yellows easily; aliphatic type is non-yellowing but expensive. If you make transparent phone cases and choose the wrong system, yellowing and stickiness will come together.
There are many global TPU players, but high-end grades are concentrated in a few major foreign manufacturers. Based on market share and production capacity, based on industry research reports and public company data (2025–2026):
1. BASF (Germany): Elastollan® brand, about 15% share, hardness grades from 60A to 75D;
2. Covestro (Germany) :D esmopan® brand, market share about 13%–20%, full range of aromatic and aliphatic types;
3. Lubrizol (USA): Estane® brand, TPU tier player, strong in film, 3C, and cable applications.
These three plus Huntsman hold the main share of high-end TPU. For 3C transparent shells, they need no yellowing, high transparency, and drop resistance—these are the strengths of these brands and transparent brands. Where does the
TPU sub-brand come from, and what is the difference from recycled materials ?
Sub-brand logic remains unchanged: same device, same batch of polymer, all indicators meet standards and the genuine brand is used; if a few indicators slightly miss the wire, it's the secondary brand. Common issues with TPU secondary brands are slight hardness deviation, slight changes in melting finger/flow, and slightly higher yellowness index of transparent parts.
Four sources: start-and-stop head and tail materials, grade number transition materials, batches with slight exceedances caused by process fluctuations, and secondary line scraps. These are original original TPU particles, with molecular structure identical to genuine brands.
Boundary: The secondary TPU is original raw material; Recycled TPU and mixed recycled materials turn yellow, sticky, and fluctuate quickly. When making transparent phone cases, treat recycled materials as secondary brands, and after two weeks of use, they'll turn yellow and look unbearable. Another point: mixing polyester and polyether types; use polyester in hydrolytic environments, which hydrolyzes and becomes sticky after half a year. For 3C protective cases, distinguish between genuine, sub-brand, recycled, and recycled materials, then choose the right system — this is the basic skill. Packaging is suitable for large and small packaging.
BASF Elastollan®: A long-established brand with full hardness coverage
Let's look at BASF first. BASF Germany's Elastolan® is their signature TPU, ranging from 60A soft to 75D hard, with a complete range of polyester, polyether, and polycaprolactone systems, as well as UV resistance, flame retardant, anti-static, and food contact grade. For automotive, footwear, and industrial parts, Elastolan® is a veteran.
Elastollan® sub-brand, mostly batches with slight hardness or flow deviations. It is suitable for structural parts, sheaths, and general protective cases that are non-transparent and do not require strict yellowing. However, for high-transparency and non-yellowing phone case main surfaces, their aliphatic transparent genuine products must be used; secondary products are only used on non-main surfaces, linings, and color-matching parts.
Covestro Desmopan®: Transparency and Anti-Yellowing Trend
Looking at Covestro Again. Germany's Covestro, Desmopan® is their TPU brand, with a complete range of aromatic and aliphatic products. Aliphatic non-yellowing grades are highly recognized for transparent 3C and outdoor accessories. It has a good reputation for transparency, hydrolysis resistance, and resilience.
Desmopan® secondary brand, suitable for general protective covers and liners with moderate transparency requirements and those not exposed to long-term outdoor sunlight. For long-term outdoor use and main display transparent cases, don't skip the official aliphatic brand. Its secondary brand is used for linings, buttons, and edgings, offering considerable value for money.
Lubrizol Estane®: Films and 3C Precision
Looking at Lubrizol again. Lubrizol's Estane® TPU from the USA excels in film, 3C, cable, and adhesive applications, with fine grades and stable performance. It follows a refined application route, making high-transparency, tactile, and wear-resistant small parts very suitable.
Estane® secondary brand, suitable for 3C accessories, edgings, and liners outside the main display surface, where you need moderate feel and wear resistance. Its quantity isn't as large as BASF's, but the carefully selected secondary brands are very reliable for phone case accessories. If you want a transparent main surface that won't turn yellow, don't skimp on the genuine brand.
TPU how to choose a secondary brand, the phone case factory has three hurdles :
makes 3C protective cases with TPU secondary brands, and these three hurdles must be passed.
first hurdle: choose a system. If it must be transparent and not yellow, choose aliphatic products; If it must be resistant to hydrolysis and low temperatures, use polyether; If it must be resistant to wear and oil, use polyester. If you choose the wrong system, even the cheapest material will be wasted. Second checkpoint: Measure yellowness and hardness. When secondary brands arrive at the factory, conduct yellowing index, hardness, and wear resistance tests; avoid secondary brands with high yellow content on the main side of transparent cases. Third checkpoint: Use different uses. For transparent main display cases, use genuine aliphatic products; secondary cases are only used for lining, edging, and non-main surfaces.
Common pitfalls: Using polyester for polyether makes it sticky in summer; Mistaking aromatic compounds for aliphatic types, turning yellow in two weeks; Using recycled materials as a secondary brand, feeling sticky and losing powder. Anyone who makes phone cases knows that if a case turns yellow or sticky, the customer returns not just that case, but the brand's reputation.
Cologne warehouse in stock | TPU prototyping
Main brands: BASF, Covestro, Lubrizol
Main grades: Elastollan series, Desmopan series, Estane series
Packaging specifications: Both large and small packages are in stock
warehouse stock usually around 4000 tons
Small parcel sub-brand stock 600-900 tons, containerized sub-brand stock 250-450 tons, large package/ton package material stock 2650-3150 tons
Supply guarantee: inspection orders come with goods
TPU sub-brand selection tips
one set for 3C parts factories:
1. Main surface transparent and no yellowing or shelling—aliphatic genuine brand not worth saving;
2. Lining, edging, non-main surfaces—secondary brands can be used;
3. Factory certification: Elastollan®, Desmopan®, Estane®, original factory packaging;
4. System selection: transparent and non-yellowing to remove aliphatic products, hydrolyzed to remove polyether;
5. On-site testing of yellowness, hardness, and wear resistance; only sign if all three are met;
6. Don't pass polyester type as polyether type; in summer, hydrolysis causes stickiness;
7. Don't use recycled material as a secondary brand; it peels powder quickly to the hand
There is a factory in Yantai that makes mobile phone cases. Previously, to cut costs, they bought a batch of cheap “transparent TPU secondary brands” and only realized after using them that they were aromatic imitations pretending to be aliphatic. After customers put them on their phones for two weeks, the cases yellowed as if they had been used for a year and also attracted fingerprints, causing the return rate to spike to 16%. Later, we supplied them with selected secondary brands of Covestro Desmopan® and BASF Elastollan® for use only in the lining and edging, while the main transparent surface still used the genuine aliphatic grade. As a result, returns due to yellowing and stickiness dropped from 16% to 0.6%.
This is the art of TPU selection—when making 3C transparent parts, what matters is a reputation for not yellowing or becoming sticky. Secondary brands can save money on auxiliary parts, but not on the main surface’s reputation. Ningbo Kelon New Materials Co., Ltd. has years of experience manufacturing secondary brands for imported big factories, helping 3C accessory makers use secondary brands for non-main surfaces while keeping genuine grades for the main transparent surfaces. Over a year, the money saved on returns and exchanges outweighs the price difference in materials by far.
