"这餐盒一捏就软，一放潮就胀，你跟我说这是降解料？"
"老板您别急，它不是不行，是您拿正牌的期待去要求副牌了。"
做降解餐盒的车间门口，三天两头要上演这么一段对话。采购听着像推诿，其实话里有话——PSM这东西，天生就带"淀粉"两个字，怕潮、怕水、怕高温，你拿它跟纯PP比挺度、比耐水，那本来就是错位。今天把PSM讲透。
PSM是什么，为什么一潮就胀
PSM，Plastarch Material，塑化淀粉材料，说白了就是把玉米淀粉、土豆淀粉这类天然淀粉，加上甘油、山梨醇这类增塑剂，揉成能像塑料一样热塑加工的料。
它的路子跟前面说的PBS、PHA完全不同。PBS是化学合成聚酯，PHA是微生物发酵，PSM是把粮食里的淀粉"塑料化"。它成本低、生物基含量高、能堆肥降解，但天生两个毛病：一是怕水吸潮，淀粉一吸水尺寸就胀；二是耐热有限，超过六七十度就开始软。所以它最适合的，是常温、短周期的餐饮一次性制品——降解餐盒、杯盖、刀叉勺。
再把降解机理说一句。PSM的降解不靠酯键慢慢水解，而是淀粉本身就是微生物眼里的口粮，进到堆肥环境里，菌群上来就把它当主食啃，分解得干脆。它跟PBS那种"先水解再被吃"的路子比，更直接，代价就是怕潮——没用在仓库里先吸了水，那就麻烦了。做餐盒的都懂，淀粉料进厂第一件事永远是烘料。
全球做PSM/淀粉基材料的国外大厂，池子不算大。按梯队看，第一档是意大利Novamont、荷兰Rodenburg、德国FKuR。武汉华丽这类国内玩家今天不展开。
副牌规矩，先讲透再讲厂
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。同一批挤出造粒料，全项合格贴正牌，某一两个指标差一点归副牌。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。边界划死：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。PSM本身就吸潮，这四类料一旦混了，含水率根本测不准。
Novamont：Mater-Bi，淀粉基的开山鼻祖
意大利Novamont，挂着Mater-Bi这块招牌，是淀粉基生物塑料的开山鼻祖，如今归到Eni旗下Versalis体系。Terni那套装置，配混产能十几万一年，玉米淀粉加可降解聚酯，做购物袋、地膜、餐饮制品都是标杆。
它家副牌的特点是配方体系成熟，副牌粒子的力学指标跟正牌差距小，常见偏离在含水率或色相。用在常温降解餐盒、杯盖这类短周期制品上，很顺。大包装小包装都在流通。
Rodenburg：Solanyl，土豆淀粉变废为宝
第二家荷兰Rodenburg，牌子Solanyl，专拿土豆加工剩下的残余淀粉做热塑淀粉料。这路子聪明——不跟人抢粮食，用副产物淀粉。
它家副牌特点是批次略有波动，含水率和拉伸偶尔跳出正牌区间。这种料拿去做一般降解包装、非直接贴脸的餐饮制品，性价比很高。注意含水率是关键，用之前必须复烘。
FKuR：Bio-Flex，德国人的淀粉共混牌
第三家德国FKuR，挂Bio-Flex牌子，做淀粉加可降解共聚酯的共混料，注塑级、膜级都有，OK Compost认证齐全。
它家副牌常见偏离在熔指和厚度公差。用在注塑降解餐盒、刀叉勺、杯盖上，加工窗口友好。它家还有专门做3D打印丝材的牌号，路子挺活。
PSM副牌，餐饮口把含水率卡死
PSM副牌能不能用，全看含水率。
淀粉料一吸潮，注塑就起泡、胀尺寸、表面发花。所以挑货第一件事不是看价格，是测含水率——压进区间里，吸潮不开裂，餐盒壁厚才匀。第二件事是别拿它盛热汤热油，六七十度它就软，盛常温菜、轻打包，刚好。
安徽马鞍山有家做降解餐盒的客户，之前进的PSM副牌没复烘，注塑出来盒壁起泡、一叠就胀，退货率一成多。后来改成进厂先复烘把含水率压进区间，盒壁厚了、表面光了，退货率从一成二压到百分之零点几，客户验收一次过。这就是把PSM的"怕潮"脾气摸透的价值。宁波市科隆新材料有限公司做进口淀粉基副牌这些年，最常帮餐盒厂干的就是把含水率这一关卡死。
科隆仓库现货｜PSM问题
主推品牌：意大利Novamont（Mater-Bi）、荷兰Rodenburg（Solanyl）、德国FKuR（Bio-Flex）。
主要牌号：Mater-Bi、Solanyl、Bio-Flex。
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：PSM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。
收尾：四句选料口诀
PSM副牌，四句记牢：
一，含水率先测、进厂先复烘，压进区间再上机；
二，做常温餐盒、杯盖、刀叉勺用副牌，别拿来盛热汤热油；
三，短周期一次性制品上副牌，走高温耐水件上正牌或别的料；
四，原厂原生淀粉粒子，别把回料再生料当副牌捡。
做降解餐盒、做淀粉基制品的，谁没被吸潮坑过？是注塑一泡就胀？还是一放潮盒盖就翘？又或是贪便宜进的料含水率根本不对？
"This lunch box becomes soft with a pinch and swells when it's damp, and you're telling me this is biodegradable material?"
Boss, don't worry. It's not that it can't do it; it's just that you're expecting the name brand from the generic one.
At the entrance of the workshop that makes biodegradable meal boxes, this kind of conversation happens every few days. To a purchaser, it might sound like passing the buck, but there’s more to it—PSM naturally has the word 'starch' in it, making it sensitive to moisture, water, and high temperatures. Comparing its stiffness and water resistance to pure PP is inherently mismatched. Today, let’s explain PSM thoroughly.
What is PSM, and why does it swell when wet?
PSM, Plastarch Material, plasticized starch material, in simple terms, is taking natural starches like corn starch and potato starch, adding plasticizers like glycerol and sorbitol, and kneading them into a material that can be thermoplastically processed like plastic.
Its approach is completely different from the PBS and PHA mentioned earlier. PBS is a chemically synthesized polyester, PHA is produced by microbial fermentation, and PSM is making the starch in grains 'plasticized.' It is low-cost, has a high bio-based content, and is compostable, but it has two inherent problems: first, it is sensitive to water and moisture—starch swells when it absorbs water; second, its heat resistance is limited, and it starts to soften above sixty to seventy degrees Celsius. Therefore, it is best suited for room temperature, short-cycle disposable food service products—compostable lunch boxes, cup lids, and cutlery.
Let me explain the degradation mechanism again. PSM doesn't degrade through the slow hydrolysis of ester bonds; starch itself is food for microbes. Once it enters a composting environment, the microbial community treats it as a main meal and breaks it down quickly and completely. Compared to PBS, which follows the 'hydrolyze first, then get eaten' route, it’s more direct, but the downside is that it’s sensitive to moisture—if it absorbs water in the warehouse before use, that’s a problem. Anyone making food containers knows that the first thing to do with starch-based material when it enters the factory is always to dry it.
The global major foreign manufacturers producing PSM/starch-based materials have relatively small pools. Looking at the tiers, the first tier includes Italy's Novamont, the Netherlands' Rodenburg, and Germany's FKuR. Domestic players like Wuhan Huali will not be discussed today.
Auxiliary brand rules: explain thoroughly first, then talk about the factory
As usual, let's clarify the secondary cards first.
The secondary grade comes from the same manufacturer and the same brand, but during factory inspection it didn't fully meet the primary brand's standards. For the same batch of extruded granules, if all items meet the standards, they are labeled as the primary brand; if one or two indicators are slightly off, they are classified as the secondary grade. These are original factory granules, with molecular structures consistent with the primary brand, not reprocessed from crushed material.
Four sources: leftover material from starting and ending production runs, transitional material during grade switching, batches with slight exceedances in individual indicators due to process fluctuations, and leftover material from secondary production lines. Boundaries are strict: the main grade fully meets standards; the secondary grade may have slight deviations in individual indicators, but the base material hasn't been changed; reprocessed material comes from machining scraps that are remelted, adding an extra heating step; recycled material is made from waste plastic, so its performance is unstable. PSM itself absorbs moisture, and once these four types of material are mixed, the moisture content cannot be accurately measured.
Novamont: Mater-Bi, the pioneer of starch-based materials
Italy's Novamont, known for the Mater-Bi brand, is a pioneer of starch-based bioplastics and is now part of Eni's Versalis system. The facility in Terni, with a combined annual production capacity of over a hundred thousand, uses corn starch plus biodegradable polyester to make shopping bags, mulching films, and catering products, all of which are industry benchmarks.
The sub-brand of this company is characterized by a mature formulation system, and the mechanical properties of the sub-brand's particles are close to those of the main brand, with common differences in moisture content or color. It works smoothly for short-cycle products like room-temperature degradable lunch boxes and cup lids. Both large and small packages are circulating.
Rodenburg: Solanyl, Turning Potato Starch from Waste into Treasure
The second Dutch company, Rodenburg, with the brand Solanyl, specializes in using leftover starch from potato processing to make thermoplastic starch materials. This approach is clever—it doesn't compete with food, using by-product starch instead.
Its sub-brand is characterized by slight batch fluctuations, with moisture content and tensile strength occasionally falling outside the range of the main brand. This material is very cost-effective for making general degradable packaging and food service products that do not directly contact the face. Note that moisture content is key, and it must be re-dried before use.
FKuR: Bio-Flex, the Germans' starch blend brand
The third German company is FKuR, under the Bio-Flex brand, producing blends of starch and biodegradable copolyesters, with both injection molding and film grades, and complete OK Compost certification.
Their sub-brands commonly have deviations in melt index and thickness tolerance. They are used for injection-molded biodegradable lunch boxes, cutlery, and cup lids, with a processing window that is user-friendly. They also have specific grades for 3D printing filaments, so their approach is quite flexible.
PSM sub-brand, the moisture content in the catering mouth is locked
Whether the PSM by-product can be used depends entirely on the moisture content.
As soon as starch material absorbs moisture, it will bubble, expand in size, and have surface whitening during injection molding. So the first thing when selecting it isn’t looking at the price but measuring the moisture content—if it’s within the range, it won’t crack when pressed, and the wall thickness of the food box will be uniform. The second thing is not to use it for hot soup or hot oil, as it will soften at sixty to seventy degrees; using it for room temperature food and light packing is just right.
There is a client in Ma'anshan, Anhui, that produces biodegradable food containers. Previously, they used a secondary brand of PSM without pre-drying, which caused the molded container walls to bubble and stacks to swell, resulting in a return rate of over 10%. Later, they changed to pre-drying the material at the factory to bring the moisture content into the proper range. As a result, the container walls became thicker, the surface smoother, and the return rate dropped from 12% to just a few tenths of a percent, passing client inspection in one go. This demonstrates the value of fully understanding PSM's 'moisture-sensitive' nature. Over the years, Ningbo Kolon New Materials Co., Ltd., which produces imported starch-based secondary brands, most often helps food container factories by strictly controlling the moisture content.
Cologne Warehouse Spot｜PSM Issue
Main promoted brands: Italy's Novamont (Mater-Bi), Netherlands' Rodenburg (Solanyl), Germany's FKuR (Bio-Flex).
Main brands: Mater-Bi, Solanyl, Bio-Flex.
Packaging specifications: Both large and small packages are available. Small packages are for trial runs and sampling, while large packages and ton bags are for mass production and cost dilution.
Warehouse Stock: PSM secondary brand warehouse stock is usually around 4,000 tons, with continuous inventory throughout the year.
Among them, 600-900 tons of small-package secondary brand are stocked, 250-450 tons of boxed secondary brand are stocked, and 2,650-3,150 tons of large-package/per-ton materials are stocked, to be flexibly dispatched according to the order ratio.
Supply Assurance: Test reports accompany the goods, and each batch's indicators can be verified.
Finishing: Four-line selection formula
PSM subsidiary brand, remember these four sentences:
1. First measure the moisture content, re-dry before entering the factory, and then run on the machine after compressing in the interval;
Second, use secondary brands for room-temperature lunch boxes, cup lids, and cutlery, and do not use them to hold hot soup or oil;
3. For short-cycle disposable products, attach the secondary label, and for high-temperature and water-resistant parts, attach the main label or use other materials.
4. Original factory native starch particles, don't mistake recycled material for a lower-grade product.
Who in the business of making degradable meal boxes or starch-based products hasn't been trapped by moisture? Is it that injection molding swells after a soak? Or that the lid warps as soon as it gets damp? Or is it that the cheap materials purchased have a moisture content that is completely off?
