降解材料这个圈子，水比你想的深。
同样三个字开头的缩聚酯，PBST、PBAT、PBSA，外行看商标都长一个样，价格能差出小一半，性能更是天差地别。最常见的一乱，就是把PBST当成PBAT买，回头做出来的包装件耐热不达标、一蒸就变形，还骂厂家发错货。
今天不绕弯子，把PBST这一个小众却关键的品类，连同全球真正懂它的几家国外大厂，一次说清。
PBST是什么，跟PBAT到底差在哪
PBST，聚丁二酸丁二醇酯-对苯二甲酸丁二醇酯共聚酯。听着绕，说白了就是在PBS的分子链上，接进了一小段对苯二甲酸丁二醇酯。
这一截接进去，目的很明确：把纯PBS偏软、耐热偏弱的短板补上。加了对苯二甲酸那一段，熔点往上抬，刚性和拉伸强度跟着上来，做出来的制品更挺括、更耐热。但代价是，它比纯PBS稍微难加工一点，熔体流动性会打折扣。
这里必须把最容易混的点说死：PBST不是PBAT。PBAT是己二酸-对苯二甲酸-丁二醇共聚酯，BASF的ecoflex就是这一类，主打软膜；PBST是丁二酸-对苯二甲酸-丁二醇共聚酯，主打比PBS更硬更耐热的结构件和包装。一个偏软膜，一个偏挺件，别拿错牌号。
再往深说一层。纯PBS偏软、熔点一百一十多度出头，做需要挺括的包装件总差口气；纯PBAT太软，又撑不起结构。PBST卡在中间这个位置——把对苯二甲酸那一段接进去，结晶度和刚性提上来，耐热也跟着上去，正好做那种"要能立得住、又要能降解"的包装卡扣、内托、一次性硬质件。这就是它存在的意义，不是凑数的第九个名字。
全球真正在PBST这条线上有技术积累的国外大厂，池子不大。按梯队看，第一档是德国BASF、日本Resonac（原昭和电工），以及三菱化学体系的PTT MCC Biochem。这个品类本身小众，海外量产规模有限，按梯队写更实在，不硬排座次。
副牌先讲规矩，再讲大厂
老规矩，先把副牌说清楚。
副牌是同一厂家同一牌号里，出厂检验没完全踩到正牌指标的部分。同一批缩聚料全项合格贴正牌，个别指标差一点归副牌。原厂原生粒子，分子结构跟正牌一条线，不是粉碎回炉。
四个来源：开停车头尾料、牌号切换过渡料、工艺波动个别指标小幅超标的批次、副线尾料。边界划清：正牌全达标；副牌个别指标小偏、基材没换；回料是加工边角料回炉，多一道热；再生料是废塑料再造，性能飘忽。别把三类料混着买。
BASF：把共聚酯玩得炉火纯青的德国大厂
德国BASF，做生物降解共聚酯是老资格。它家ecoflex、ecovio一系产品，在可堆肥包装领域名声响。虽然ecoflex本体更接近PBAT体系，但BASF在丁二酸-对苯二甲酸共聚酯这条技术线上的积累，是行业公认的。
它家副牌的特点是品控体系严，过渡料和切换料分得干净，副牌粒子的力学指标跟正牌差距小，常见偏离在色相或熔指。用在对挺括度有要求、但不走食品级极限认证的包装件、内衬结构件上，很稳。大包装小包装都在流通。
Resonac：Bionolle家族里的硬派分支
日本Resonac（原昭和电工）的Bionolle家族，不光有软的PBS/PBSA，也有带对苯二甲酸共聚、偏向更耐热挺括的分支。它家在缩聚共聚这块的工艺积累很深。
Bionolle体系里这类偏硬副牌，常见偏离项在熔体流动性和色相。用它做包装卡扣、内托、一般结构件，挺劲够。注意这种料别上来就冲超薄透明膜，它的长处不在软，在硬。
PTT MCC Biochem：BioPBS的共聚延伸
第三家泰国PTT MCC Biochem，三菱化学技术体系，BioPBS。它在PBS共聚物延伸上有布局，对苯二甲酸改性的牌号也有涉及。
它家副牌常偏离在认证线附近，性能本身往往没塌，只是生物基含量或色相这一格没踩线。拿去做非直接食品接触的降解包装材料，性价比实在。
PBST副牌，认准"硬"字挑
PBST副牌挑货，记住一个字：硬。
它的长处是比PBS挺、比PBAT耐热，短处是流动性不如纯PBS。所以挑货先看偏离项：要是偏在色相、灰分这种不影响力学的项上，放心用；要是偏在熔指、流动性上，那就得对着你的壁厚和注塑工艺重新调。日照有家做降解包装结构件的客户，之前把PBST副牌当PBAT软膜料上机，一注塑就充不满，良率掉一半。后来认清牌号，把流动性数据对上壁厚，良率从五成拉到九成五，单价还比纯正牌低一块。这就是分清楚PBST和PBAT的价值。宁波市科隆新材料有限公司做进口共聚酯副牌这些年，这种"认牌号、对用途"的账，帮客户算得很细。
科隆仓库现货｜PBST出货
主推品牌：巴斯夫BASF（ecoflex/ecovio）、Resonac原昭和电工（Bionolle）、泰国PTT MCC Biochem（BioPBS）。
主要牌号：ecoflex、ecovio、Bionolle共聚分支、BioPBS。
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：PBST副牌仓库现货通常在3000-6000吨，常年备货不断档。
其中小包副牌备货500-800吨、箱装副牌备货200-400吨、大包料/吨包料备货2500-4800吨，按订单配比灵活出。
供应保障：原厂原包直采，批次留样可追。
收尾：四句选料口诀
PBST副牌，四句记牢：
一，先认清PBST不是PBAT，硬派别当软料用；
二，偏在色相灰分放心用，偏在流动性要重新调机；
三，做挺件、做内托用副牌，走超薄透明膜上正牌；
四，原厂原生粒子，别把回料再生料当副牌捡。
做降解包装、做共聚酯改性的，谁没被牌号坑过？是把PBST当PBAT充不满模？还是一蒸就变形？又或是货进来才发现根本不是同一系列？
In the field of degradable materials, the waters are deeper than you think.
Similarly, three polyester copolymers starting with the same three letters, PBST, PBAT, PBSA, look the same to outsiders when looking at the label, but their prices can differ by nearly half, and their performance is completely different. The most common mix-up is buying PBST thinking it is PBAT, only to find that the packaging made from it does not meet heat resistance standards, deforms after a single steaming, and then people complain that the manufacturer shipped the wrong product.
Let's not beat around the bush today and clearly explain the niche but crucial category of PBST, along with the few foreign major manufacturers who truly understand it worldwide.
What is PBST, and how is it different from PBAT?
PBST, poly(butylene succinate-co-butylene terephthalate) copolyester. It sounds complicated, but simply put, it means that a small segment of poly(butylene terephthalate) is incorporated into the PBS molecular chain.
This segment is added for a very clear purpose: to compensate for the shortcomings of pure PBS, which is relatively soft and has weak heat resistance. By adding the part with terephthalic acid, the melting point is raised, and the stiffness and tensile strength increase accordingly, making the products more robust and heat-resistant. But the trade-off is that it is slightly more difficult to process than pure PBS, and the melt flowability is reduced.
We have to make the most easily confused point absolutely clear: PBST is not PBAT. PBAT is a copolyester of adipic acid, terephthalic acid, and butanediol; BASF's Ecoflex belongs to this category and is mainly used for soft films. PBST is a copolyester of butanediol, terephthalic acid, and succinic acid, mainly used for more rigid and heat-resistant structural parts and packaging than PBS. One is more for soft films, the other for rigid parts, so don't confuse the grades.
Let's go a layer deeper. Pure PBS is relatively soft, with a melting point just above 110 degrees, making it always somewhat lacking for packaging that needs to be stiff; pure PBAT is too soft and can't support the structure. PBST sits right in the middle — by incorporating the segment from terephthalic acid, its crystallinity and rigidity are increased, and its heat resistance goes up as well, making it just right for packaging clips, trays, or disposable rigid parts that 'need to stand on their own but also be degradable.' This is its reason for existing, not just a ninth name thrown in for the sake of it.
There are few major foreign companies worldwide that truly have technical accumulation in the PBST line. Looking at tiers, the first tier includes Germany's BASF, Japan's Resonac (formerly Showa Denko), and the PTT MCC Biochem under the Mitsubishi Chemical group. This category itself is niche, and the scale of mass production overseas is limited. It’s more practical to describe them by tiers rather than strictly ranking them.
The secondary brand first talks about rules, then talks about big factories.
As usual, let's clarify the secondary cards first.
The secondary grade comes from the same manufacturer and the same grade, but during factory inspection, it did not fully meet the official grade standards. In the same batch, if the polymer meets all the requirements, it is labeled as the official grade, while those slightly off in some indicators are considered secondary grade. It is made from the original factory's raw particles, with a molecular structure consistent with the official grade, and is not reprocessed from crushed material.
Four sources: leftover materials from starting and stopping production, transitional materials caused by grade switching, batches with slight exceedances due to process fluctuations, and leftover materials from secondary lines. Clear boundaries: the main brand fully meets standards; the secondary brand has slight deviations in some indicators but the base material hasn't changed; reprocessed material is from machining scraps re-melted with an extra heating step; recycled material is made from waste plastic, with unstable performance. Do not mix these three types of materials when purchasing.
BASF: The German giant mastering copolyesters to perfection
Germany's BASF has long been experienced in biodegradable copolyesters. Its ecoflex and ecovio product lines are well-known in the compostable packaging field. Although ecoflex itself is closer to the PBAT system, BASF's accumulation of technology in the succinic acid-terephthalic acid copolyester line is recognized by the industry.
The characteristic of its sub-brand is a strict quality control system, with clear separation between transitional and switched materials. The mechanical properties of the sub-brand particles are close to those of the main brand, with common deviations mainly in color hue or melt index. It performs very reliably in packaging components and liner structural parts that require stiffness but do not go for food-grade extreme certification. Both large and small packages are in circulation.
Resonac: The Hardcore Branch of the Bionolle Family
The Bionolle family from Japan’s Resona (formerly Showa Denko) not only includes soft PBS/PBSA, but also branched versions copolymerized with terephthalic acid, which are more heat-resistant and rigid. The company has deep process expertise in condensation copolymerization.
In the Bionolle system, this type of somewhat rigid secondary grade often shows variations in melt flow and color. Using it for packaging clasps, inner trays, and general structural components works well; it's sturdy enough. Note that this material should not be immediately used for ultra-thin transparent films—its strength lies not in softness, but in hardness.
PTT MCC Biochem: Copolymer Extension of BioPBS
The third Thai company is PTT MCC Biochem, using the Mitsubishi Chemical technology system, BioPBS. It has a layout in PBS copolymer extension and also involves grades modified with terephthalic acid.
Its sub-brand often deviates near the certification line; the performance itself usually doesn’t fail, it’s just that it falls short in one aspect, such as the bio-based content or color tone. Using it to make biodegradable packaging materials for non-direct food contact applications is truly cost-effective.
PBST sub-brand, look for the 'hard' character
PBST sub-brand selection, remember one word: tough.
Its strengths are that it is stiffer than PBS and more heat-resistant than PBAT, while its weakness is that its flowability is not as good as pure PBS. So when selecting materials, first look at the deviating properties: if the deviation is in aspects like color or ash content that do not affect mechanical properties, you can use it without worry; if the deviation is in melt index or flowability, then you need to adjust according to your wall thickness and injection molding process. There is a client specializing in biodegradable packaging components in Rizhao who previously treated a secondary grade of PBST as PBAT soft film material, and when injected, it couldn’t fill the mold, cutting yield by half. Later, after recognizing the correct grade and matching the flow data with wall thickness, the yield increased from 50% to 95%, and the unit price was even one yuan lower than the genuine grade. This illustrates the value of distinguishing between PBST and PBAT. Ningbo Cologne New Materials Co., Ltd. has been producing imported secondary grades of copolyesters for years, and they calculate the 'knowing the grade and matching it to the application' very precisely for their clients.
Cologne Warehouse Spot｜PBST Shipment
Main promoted brands: BASF (ecoflex/ecovio), Resonac (former Showa Denko) (Bionolle), Thailand PTT MCC Biochem (BioPBS).
Main grades: ecoflex, ecovio, Bionolle copolymer branch, BioPBS.
Packaging specifications: There are both large and small packages. Small packages are for trial runs and samples, while large packages and ton bags are for mass production and cost dilution.
Warehouse stock: PBST secondary brand warehouse stock is usually between 3,000-6,000 tons, with year-round supply continuously available.
Among them, small packaged secondary brand stock is 500-800 tons, boxed secondary brand stock is 200-400 tons, and large package material/ton package material stock is 2500-4800 tons, distributed flexibly according to order ratios.
Supply assurance: Direct procurement from the original factory with original packaging, batch samples retained for traceability.
Finishing: Four-line selection formula
PBST sub-brand, remember these four sentences:
1. First, recognize that PBST is not PBAT; don't use a rigid type as if it were a soft material.
Second, it is safe to use when the hue leans toward gray, but the flowability needs to be readjusted.
3. For making bras and inner supports, use secondary brands, and apply the main brand on ultra-thin transparent film;
Fourth, original factory native particles, don’t take recycled material as a secondary choice.
For those working on degradable packaging or copolyester modification, who hasn't been screwed over by grades? Is it using PBST as PBAT and failing to fill the mold? Or does it deform after just one steaming? Or do you only find out when the goods arrive that it's not even from the same series?
