做鞋材、做车衣膜、做软管的同行，谁没对着一沓涨价函叹过气？新料TPU一年比一年贵，可回弹这东西不跟你讲道理，也不看你报价单。客户上脚一踩、手一捏，软不软、弹不弹、塌不塌，立刻就知道行不行。今天这篇，就把再生TPU怎么选、回弹能剩几成、什么件该用什么型、别踩哪些坑，一次讲个明白。
先花两分钟认识下主角。TPU学名叫热塑性聚氨酯，是一种“硬段+软段”拼起来的弹性体：硬段负责撑强度，软段负责给弹性，调一调软硬段的比例，硬度能从邵氏45A一直拉到85D，软的像橡皮筋，硬的像塑料壳。它耐磨、回弹好、耐油，做出来的东西你天天见——运动鞋的中底和外底、汽车隐形车衣膜、气动软管、手机软壳、线缆护套、密封圈，都是它的地盘。宁波市科隆新材料有限公司做塑料原料供应，工贸一体，常见再生塑料品类常年备货，TPU是其中靠手感和回弹说话的一个。
再生TPU的来源，主要是鞋材厂、薄膜厂、软管厂的干净水口和边角料，再加上一部分消费后的弹性体制品回收。它跟PP、ABS不一样的地方在于：TPU分聚酯型和聚醚型两大类，这俩出身不同、脾气完全不同，混在一起再生，等于把弹簧和海绵搅成一团，性能全乱。所以再生TPU的头一道功夫不是造粒，是分型——聚酯归聚酯，聚醚归聚醚，脂肪族另算。宁波市科隆新材料有限公司在配再生TPU时，先问客户用在哪、泡不泡水，再定类型，不拿一种料包打天下。
弹性体再生，先分聚酯和聚醚，不然回弹都是白谈
一提再生TPU，不少采购心里直犯嘀咕：弹性体嘛，回炉再弹不就完了？这话只说对一半。TPU能不能再生，先得看它是哪一类软段——聚酯和聚醚的“死穴”，压根不是一个路数。
聚酯型TPU，软段是聚酯结构，强项是耐磨、耐油、拉伸强度高，常温室内用着实惠，缺点是怕水怕潮——聚酯链遇到热水、有机酸，时间一长会水解，表面粉化、开裂。你拿再生聚酯TPU去做常年泡水的软管，它撑不了多久。聚醚型TPU，软段是聚醚结构，强项是耐水解、抗霉菌、低温下还软，零下几十度不脆裂，缺点是耐磨和耐油略逊于聚酯，价格也贵些。行业里有句选型口诀：干燥耐磨选聚酯，涉水耐候选聚醚。
再生时这个分型更加要紧。新料聚酯怕水，再生过一回、热历史更复杂的聚酯，水解风险只增不减；聚醚本来耐水，回用得当反而能保住它的长板。要是把聚酯和聚醚打碎混在一起再生，两种软段互不买账，回弹、耐磨、耐水全都不突出，做成的东西软不软硬不硬，客户一捏就露馅。所以再生TPU行业里有个朴素共识：同源再生最稳——聚酯水口还做聚酯件，聚醚水口还做聚醚件，别跨类型乱配。
这里还要多提一种——脂肪族TPU。前面说的聚酯、聚醚，指的都是软段；芳香族还是脂肪族，说的是硬段的类型。芳香族TPU便宜、力学好，但放久了、晒了太阳容易黄变；脂肪族不含苯环那类基团，抗紫外、不黄变，透明度也好，做汽车隐形车衣膜、透明护套就是它的主场，代价是更贵。再生时也是一个道理：做车衣膜的透明边角料，黄变控制得好才值钱；拿普通芳香族再生料去冒充抗黄变料，客户晒一个夏天就露馅。类型这道题，在TPU这里是绕不过去的。
图1 TPU薄膜、软管与软质件
TPU的软硬段，像弹簧里塞了钢筋
为啥TPU一捏就软、一松就弹得回来？靠的就是它“软段当弹簧、硬段当钢筋”的结构。理解了这个，你才知道再生时哪部分在掉链子。
TPU分子链上，软段像弹簧，提供拉长和回弹；硬段像一个个物理交联点，像钢筋把弹簧拉住，撑住强度和形状。新料TPU回弹恢复率能做到九成上下，回弹率五成以上，踩下去快、弹回来也快。再生的时候，分子链受了热和剪切，硬段和软段都会有一定程度的断裂——弹簧断了圈，回弹就慢一点、塌一点；钢筋松了劲，强度和耐磨也跟着降。这就是为什么“再生后回弹还能剩几成”这个问题，不能用一个数字回答：干净水口、低温快过、补了助剂的，回弹保持得好；来源杂、反复回炉的，回弹和硬度都飘。
具体到“回弹”这个事，行业里有几个能对上的数字：高性能TPU做成的跑鞋中底，弹性恢复率能到九成以上，回弹率能做到五成上下；耐磨性比普通橡胶高出好几倍，磨耗数值很低。这些是新料的水平。再生TPU能保住多少，取决于热历史——同厂水口、一次回用、低温快造的，回弹和耐磨掉得不明显；反复加工的，硬段物理交联点被破坏，材料会慢慢变“死”，踩下去弹不起来，拉伸伸长也往下走。所以问“再生后回弹还剩几成”，正确的答案不是一个固定百分比，而是一句：看它回了几次炉、类型对不对、助剂补没补。
正规再生TPU的路子是：先按类型分好，再破碎、清洗、干燥——TPU吸水率不低，含水造粒会水解降解，干燥这步偷不得；然后低温挤出造粒，尽量少受热；最后根据用途，补点润滑剂、抗水解剂、抗氧剂，把软硬段的平衡重新调回来。做鞋底和缓冲件的，重点看回弹和压缩永久变形；做软管和护套的，重点看耐水解和低温。下面这张等级表，就是按类型和来源分的。
| 等级 | 主要来源 | 关键指标 | 典型用途 |
|---|
| 聚酯型再生TPU（干净水口） | 鞋材/薄膜工厂聚酯水口 | 邵氏约70A-95A，耐磨耐油，回弹保持较好 | 鞋底、脚轮、密封、耐油件 |
| 聚醚型再生TPU | 聚醚工厂水口 | 耐水解、低温柔韧，回弹稳定 | 涉水软管、线缆护套、户外件 |
| 脂肪族再生TPU | 车衣膜/透明膜边角料 | 抗UV不黄变，透明度较好 | 车衣膜、透明护套、户外件 |
| 鞋材发泡再生TPU | ETPU中底/鞋垫废料 | 回弹率高，需严格控含水率 | 鞋垫、缓冲件、改性掺混 |
| 通用掺混再生TPU | 多来源混合造粒 | 硬度漂移，性能波动偏大 | 非关键缓冲、低档日用品 |
| 改性再生TPU | 再生料加阻燃或填充 | 特定功能，需复配验证 | 线缆、护套、功能件 |
说明：TPU再生目前主要参照GB/T 40006.1《塑料 再生塑料 第1部分：通则》及各生产企业的企业标准；聚酯型、聚醚型、脂肪族性能差异较大，表中指标为行业公开资料与厂家技术数据归纳，更多等级与物性参数以厂家官方TDS为准。
回弹少一截，鞋就少一脚劲
再生TPU是便宜，可弹性体的钱不能只盯着吨价比，得比回弹、比手感。你算啊，一千克料省个几块钱，做成鞋垫客户踩三个月就塌了，那点优惠转头就赔回去，还得搭上名声。
再生TPU这两年为什么热？因为它的应用盘子太大了。鞋材，尤其是发泡中底和鞋垫，废料量不小；车衣膜市场扩得快，膜边角料也跟着多；再加上软管、线缆护套、手机壳，边角料来源稳定。问题在于，TPU价值密度高、应用分散，再生料能不能用，高度依赖分型和配方，不是简单洗洗造粒就能成气候。谁能把同类型水口收好、把回弹和含水率控住，谁在这个细分里就站得稳。这也是为什么再生TPU看着热闹，真能稳定供货的没几家。
| 成本项 | 新料TPU | 再生TPU | 差异说明 |
|---|
| 吨料价 | 较高 | 同类型水口低一截 | 同源干净水口差价实在，杂料更便宜 |
| 回弹保持 | 回弹率高，回复快 | 干净水口保持较好，杂料回弹掉 | 回弹是弹性体命门，一踩便知 |
| 硬度稳定 | 批次稳 | 热历史不同硬度漂移 | 硬度差几度，手感就不对 |
| 耐水解 | 按类型 | 再生聚酯更怕水 | 涉水件别用再生聚酯 |
| 批次一致性 | 高 | 同厂水口稳，杂料波动大 | 杂料调机费时间 |
| 综合成本 | 基准 | 同源水口划算，跨型混用风险高 | 类型对了才省，混型白省 |
结合这笔账，下面的边界清单帮你判断手里的件能不能上再生TPU。
适合用再生TPU：同类型干净水口直接回用；室内干燥、非涉水的耐磨缓冲件；鞋底、脚轮、手机壳、普通包装件。
涉水、户外潮湿、常年泡水的件：别用再生聚酯，要用再生聚醚。
车衣膜、透明耐候、要求不黄变的件：认准脂肪族再生，普通芳香族再生别碰。
对回弹、压缩永久变形要求高的高端鞋垫：别用杂料，看回弹报告。
食品接触、医疗级件：需对应合规，普通再生料别上。
最后再补一句加工上的提醒。TPU天生吸潮，再生料更是如此，上机前一定要按要求烘到含水率达标，否则一受热水分就把分子链打断，做出来的件发脆、表面起泡。料温也别一味求高，TPU过热会黄变、降解，按厂家推荐的窗口走就行。还有，再生TPU硬度和新料可能差几度，模温、注射速度都要跟着微调，别拿新料的参数硬套，否则手感和尺寸都对不上。这些工序上的小心，往往比选对料更影响成品手感。
鞋底踩三个月塌不塌，料里软硬段说了算
讲一段在鞋垫圈里常见的经历——宁波市科隆新材料有限公司做的就是这行，情节是典型情景，不特指某一家。
南方有家做鞋垫和缓冲垫的厂，想降成本，进了一批便宜的再生TPU做鞋垫。新鞋垫刚踩上去还行，软弹适中，可客户穿了两三个月反馈：鞋垫踩扁了，弹不回来，越穿越硬。拆开一看，这批再生料软硬段配比飘、含水率偏高，回弹早就在反复弯折里耗光了。一批鞋垫被要求调换，库存还压了一仓库。
经同行介绍，这家厂的老板专程来拜访科隆新材。科隆新材没先谈价，先问鞋垫是室内用还是常出汗涉水、对回弹寿命要求多高。弄明白后给的建议是别再用那种跨类型混掺的料：室内干燥鞋垫，用聚酯型干净水口再生TPU，补好抗水解和润滑，回弹保持得住，价格比新料实在；如果是容易受潮出汗的鞋垫，就别硬上聚酯，换聚醚型再生，虽然贵一点，但不水解、不易塌。同时要求每批测邵氏硬度和回弹、压缩永久变形，料烘透再上机，含水率不达标坚决不开机。
科隆新材还教了这家厂一个土办法：新料和再生料各压一片试片，用手反复弯折、揉捏几十下，新料折完纹路快、回弹跟手；再生料要是折两下就发白、回弹慢半拍，这批料心里就有数了。再就是别省检测，邵氏硬度、回弹率、压缩永久变形三个数，每批对着看，批次稳不稳一目了然。TPU手感这东西，骗不过天天用手做货的师傅，也骗不过踩三个月的脚。
换料之后，鞋垫的回弹投诉明显少了，库存周转也正常了。TPU这东西骗不了脚——料行不行，踩三个月就见分晓。这也是宁波市科隆新材料有限公司配再生TPU时，坚持按类型、按用途选型，而不是报个低价就发货的原因——手感这一关，省什么都不能省。
弹性体换再生料，先看它泡不泡水
翻到这一步，把要点收成一张表，照着对号入座就行——再生TPU降本不假，但前提是别把干燥件和涉水件、聚酯和聚醚搅成一锅。记住那句口诀：干燥耐磨选聚酯，涉水耐候选聚醚，透明耐候找脂肪族——三条线对号入座，再生TPU才弹得回来、省得下去，客户的脚和手也才买账。
| 应用场景 | 推荐等级 | 注意事项 | 何时别用 |
|---|
| 鞋底/脚轮耐磨 | 聚酯型再生TPU | 室内干燥用 | 涉水潮湿别用 |
| 涉水软管/线缆 | 聚醚型再生TPU | 控含水率 | 再生聚酯别碰 |
| 车衣膜/透明护套 | 脂肪族再生TPU | 看黄变与透明度 | 普通芳香族别用 |
| 鞋垫/缓冲发泡 | 鞋材发泡再生TPU | 看回弹与压缩变形 | 杂料别用 |
| 手机壳/日用品 | 通用再生TPU | 成本低 | 回弹要求高别用 |
| 阻燃功能件 | 改性再生TPU | 看阻燃等级 | 无认证别用 |
弹性体这东西，弹不弹一捏就知道——再生料行不行，踩两脚、捏两把，比看报告还准。
再生TPU，弹性体降本靠等级不靠赌
宁波市科隆新材料有限公司长期供应再生TPU热塑性聚氨酯原料，覆盖聚酯型、聚醚型、多硬度等级，应用于鞋材、车衣膜、软管、密封件、手机壳等场景。再生后回弹性还能剩几成？硬度和耐磨怎么选？别再拿一种料去试所有件，类型没选对，再便宜也是白忙。
声明：本文提及的品牌及商标权归各自原厂所有。本文为第三方选材知识分享，文中涉及的具体等级、参数、价格、认证等信息以各厂家官方最新资料为准。本文不构成任何采购或投资建议。
For those in the business of shoe materials, car protective films, or hoses, who hasn’t sighed over a stack of price increase notices? New TPU gets more expensive year by year, but rebound doesn’t care about logic or your price list. Once a customer steps on it or squeezes it with their hand, they immediately know if it’s soft, springy, or collapses. Today’s article will clearly explain how to choose recycled TPU, how much rebound can be retained, which type to use for which part, and which pitfalls to avoid.
Let's spend two minutes getting to know the main character. TPU, formally known as thermoplastic polyurethane, is an elastomer composed of 'hard segments and soft segments': the hard segments provide strength, while the soft segments provide elasticity. By adjusting the ratio of hard to soft segments, the hardness can range from Shore 45A all the way to 85D, soft like a rubber band, hard like a plastic shell. It is wear-resistant, has good rebound, and is oil-resistant. The things made from it are things you see every day—sports shoe midsoles and outsoles, automotive paint protection films, pneumatic hoses, soft phone cases, cable sheaths, and sealing rings are all its territory. Ningbo Cologne New Materials Co., Ltd. supplies plastic raw materials, integrating industry and trade, stocks common recycled plastic types year-round, and TPU is one that relies on its tactile feel and resilience.
The sources of recycled TPU mainly come from clean sprues and scraps from shoe material factories, film factories, and hose factories, along with some post-consumer elastic products recycling. Unlike PP or ABS, TPU is divided into two major types: polyester-based and polyether-based. These two have different origins and completely different properties; mixing them together in recycling is like stirring springs and sponges into a mess, ruining performance. Therefore, the first step in recycled TPU processing is not pelletizing, but classification—polyester with polyester, polyether with polyether, and aliphatic types separately. When Ningbo Kolon New Materials Co., Ltd. prepares recycled TPU, they first ask the customer where it will be used and whether it will be in contact with water, then determine the type accordingly, rather than relying on a single material for everything.
For elastomer regeneration, first separate polyester and polyether; otherwise, rebound is all talk.
Whenever recycled TPU is mentioned, many purchasers feel a bit skeptical: it's an elastomer, so can't it just be remolded? This statement is only half correct. Whether TPU can be recycled depends first on which type of soft segment it has—polyester and polyether have completely different vulnerabilities.
Polyester-based TPU has polyester segments. Its strengths are wear resistance, oil resistance, and high tensile strength. It's cost-effective for indoor use at room temperature. The downside is that it is sensitive to water and moisture—polyester chains will hydrolyze over time when exposed to hot water or organic acids, causing surface chalking and cracking. If you use recycled polyester TPU for hoses that are constantly submerged in water, they won't last long. Polyether-based TPU has polyether segments. Its strengths are hydrolysis resistance, mildew resistance, and remaining soft at low temperatures—down to several tens of degrees below zero without becoming brittle. The downside is that its wear and oil resistance are slightly inferior to polyester, and it is more expensive. In the industry, there is a selection rhyme: for dry and wear-resistant use, choose polyester; for water exposure and weather resistance, choose polyether.
This classification becomes even more important during recycling. New polyester is sensitive to water, and recycled polyester, having gone through another cycle and a more complex thermal history, only has an increased risk of hydrolysis; polyether is naturally water-resistant, and if reused properly, its advantages can be preserved. If polyester and polyether are crushed and mixed together for recycling, the two types of soft segments won’t be compatible, and elasticity, wear resistance, and water resistance will all be lacking. The resulting products will be neither soft nor hard, revealing their flaws as soon as the customer squeezes them. Therefore, there is a simple consensus in the recycled TPU industry: recycling within the same type is the most reliable — polyester scraps should make polyester parts, polyether scraps should make polyether parts, and different types should not be mixed.
Here, one more type needs to be mentioned—aliphatic TPU. The polyester and polyether mentioned earlier refer to the soft segments; whether aromatic or aliphatic refers to the type of hard segments. Aromatic TPU is cheap and has good mechanical properties, but it yellows easily when stored for a long time or exposed to sunlight; aliphatic TPU contains no benzene rings or similar groups, is UV-resistant, does not yellow, and has good transparency. Its main applications are automotive invisible paint protection films and transparent sleeves, but the cost is higher. The same principle applies when recycling: transparent scraps from paint protection films are valuable only if yellowing is well controlled; using ordinary aromatic recycled material to pretend to be anti-yellowing material will be exposed after a summer in the sun. The question of type is unavoidable when it comes to TPU.
Figure 1 TPU film, hose, and soft parts
The soft and hard segments of TPU are like steel bars stuffed inside a spring
Why does TPU get soft when squeezed and bounce back when released? It relies on its structure of 'soft segments acting as springs, hard segments acting as steel reinforcement.' Once you understand this, you'll know which part fails during recycling.
On the molecular chain of TPU, the soft segments are like springs, providing elongation and rebound; the hard segments are like physical crosslinking points, like rebar holding the springs, maintaining strength and shape. New TPU can achieve a rebound recovery rate of around 90%, with a rebound rate of over 50%, so when pressed down, it quickly springs back. When recycled, the molecular chains are subjected to heat and shear, causing a certain degree of breakage in both hard and soft segments—the spring breaks, so the rebound slows and collapses a bit; the rebar loosens, so the strength and wear resistance decrease. This is why the question of 'how much rebound remains after recycling' cannot be answered with a single number: clean sprues, fast low-temperature processing, and added additives maintain good rebound; mixed sources and repeated reprocessing cause rebound and hardness to fluctuate.
Specifically regarding 'rebound,' there are a few figures in the industry that can be referenced: for running shoe midsoles made of high-performance TPU, the elastic recovery rate can exceed 90%, and the rebound rate can be around 50%; abrasion resistance is several times higher than regular rubber, with very low wear values. These are the levels for new materials. How much reclaimed TPU can maintain depends on its thermal history—if it comes from the same factory sprue, reused once, or processed quickly at low temperatures, the loss in rebound and abrasion is not significant; with repeated processing, the physical crosslinking points in the hard segments are damaged, the material gradually becomes 'dead,' it won’t spring back when stepped on, and its tensile elongation also decreases. So when asking 'how much rebound is left after reclamation,' the correct answer is not a fixed percentage, but a statement like: it depends on how many times it’s been through the furnace, whether the type is correct, and whether any additives have been replenished.
The proper process for regenerating TPU is: first, sort it by type, then crush, wash, and dry it—TPU has a relatively high water absorption, and granulating it with moisture will cause hydrolysis and degradation, so the drying step cannot be skipped; next, extrude and granulate at low temperature, minimizing heat exposure; finally, depending on the intended use, add some lubricant, anti-hydrolysis agent, and antioxidant to restore the balance between soft and hard segments. For shoe soles and cushioning components, the focus is on rebound and permanent compression deformation; for hoses and sheaths, the focus is on hydrolysis resistance and low-temperature performance. The table below classifies the grades according to type and source.
| Level | Main source | Key indicators | Typical uses |
|---|
| Polyester-based recycled TPU (clean sprue) | Shoe Materials/Film Factory Polyester Sprue | Shao's approximately 70A-95A, wear-resistant and oil-resistant, retains good rebound | Soles, casters, seals, oil-resistant parts |
| Polyether-based Recycled TPU | Polyether Factory Water Gate | Hydrolysis-resistant, low-temperature flexible, with stable rebound | Water-resistant hoses, cable sheaths, outdoor components |
| Aliphatic Recycled TPU | Car cover film/transparent film scraps | UV-resistant and does not yellow, with good transparency | Car cover film, transparent protective cover, outdoor parts |
| Shoe Material Foamed Recycled TPU | ETPU midsole/insole waste | High rebound rate, moisture content needs to be strictly controlled | Insoles, cushioning components, modified blends |
| General Blended Recycled TPU | Multi-source hybrid granulation | Hardness drift, performance fluctuation is relatively large | Non-essential buffers, low-end daily necessities |
| Modified Recycled TPU | Recycled material with flame retardant or filler | Specific functions require combined verification | Cables, sheaths, functional components |
Note: TPU recycling currently mainly refers to GB/T 40006.1 "Plastics – Recycled Plastics Part 1: General Rules" and the corporate standards of various manufacturers; polyester-type, polyether-type, and aliphatic types have significant performance differences. The indicators in the table are summarized from publicly available industry information and manufacturers' technical data. For more grades and property parameters, the manufacturer's official TDS shall prevail.
If the rebound is a bit less, the shoes will have a bit less power.
Recycled TPU is cheap, but when it comes to elastomers, you shouldn’t just focus on the price per ton; you need to compare rebound and feel. Think about it: if you save a few bucks per kilogram of material, and it’s made into insoles that collapse after three months of use, that little discount will be lost, and you’ll also risk damaging your reputation.
Why has recycled TPU been so popular in the past two years? Because its application market is huge. For shoe materials, especially foamed midsoles and insoles, the amount of waste is not small; the car film market is expanding rapidly, and scraps from the edges of the film are also increasing; plus, there are hoses, cable sheaths, and phone cases, all providing a stable source of scraps. The problem is that TPU has a high value density and its applications are scattered, so whether recycled material can be used depends heavily on molding and formulation—it’s not something that can be solved just by washing and granulating. Whoever can properly collect similar sprue types and control rebound and moisture content will hold a stable position in this niche. This is also why recycled TPU looks lively, but there are very few companies that can truly provide a stable supply.
| Cost item | Virgin TPU | Recycled TPU | Difference Explanation |
|---|
| Price per ton of material | Higher | Slightly lower than the same type of nozzle | The price difference for clean water of the same origin is real, and miscellaneous materials are even cheaper. |
| Rebound retention | High resilience, quick recovery | The clean water outlet is maintained fairly well, and debris rebounds and drops off. | Rebound is the lifeline of elastomers; you can tell as soon as you step on it. |
| Stable hardness | Batch Stable | Thermal history different hardness drift | If the hardness is off by a few degrees, the feel is wrong |
| Hydrolysis-resistant | By type | Recycled polyester is more afraid of water | Do not use recycled polyester for water-related components |
| Batch Consistency | Tall | The same factory's nozzle is stable, but miscellaneous materials fluctuate greatly | Time spent on adjusting the machine due to miscellaneous materials |
| Comprehensive cost | Benchmark | Using the same source water inlet is cost-effective, but mixing different types carries high risk | Only when the type is correct can you save; mixing types saves nothing. |
Combining this account, the following boundary list helps you determine whether the part in your hand can be put on recycled TPU.
Suitable for using recycled TPU: direct reuse of clean water outlets of the same type; indoor dry, non-water-involved wear-resistant cushioning parts; shoe soles, casters, phone cases, ordinary packaging parts.
For items exposed to water, outdoor moisture, or soaking all year round: do not use recycled polyester, use recycled polyether instead.
Car cover film, transparent weather-resistant parts that require no yellowing: make sure to choose aliphatic resin; avoid ordinary aromatic resin.
For high-end insoles that require high resilience and resistance to permanent compression: don’t use miscellaneous materials, check the rebound report.
Food contact and medical-grade parts: must comply accordingly, ordinary recycled materials should not be used.
Finally, a reminder about processing. TPU naturally absorbs moisture, and recycled material even more so. Before molding, it must be dried to meet the required moisture content; otherwise, when heated, the moisture will break the molecular chains, resulting in parts that are brittle and have surface bubbles. Don’t just aim for high material temperatures either; overheating TPU can cause yellowing and degradation. Just follow the manufacturer’s recommended processing window. Also, the hardness of recycled TPU may differ from that of virgin material by a few degrees, so mold temperature and injection speed need slight adjustments. Don’t just use the parameters for virgin material, or the feel and dimensions may not be correct. Careful attention to these processing steps often affects the final product feel more than choosing the right material.
Whether the soles flatten after three months of wear depends on the material's softness and hardness.
Talk about an experience commonly seen in the insole industry—the company Ningbo Cologne New Materials Co., Ltd. operates in this field, and the scenario is a typical situation, not referring to any specific company.
There is a factory in the south that makes insoles and cushioning pads. They wanted to reduce costs, so they bought a batch of cheap recycled TPU for the insoles. The new insoles felt okay when first tried on—moderately soft and elastic—but customers reported after wearing them for two to three months that the insoles were flattened, didn’t bounce back, and got harder the more they wore them. Upon inspection, it was found that this batch of recycled material had inconsistent ratios of soft and hard segments and a relatively high moisture content, so the rebound had already been depleted after repeated bending. A batch of insoles had to be replaced, and the inventory ended up sitting in the warehouse.
Through peer introduction, the owner of this factory made a special visit to Kolon New Materials. Kolon New Materials did not discuss price first; they first asked whether the insoles were for indoor use or frequently exposed to sweat and water, and how high the requirements for rebound durability were. After understanding, the advice given was to stop using that type of mixed material across categories: for indoor, dry insoles, use polyester-type clean water-gate recycled TPU, properly add anti-hydrolysis and lubricants, so rebound can be maintained, and the price is more reasonable than new material; if the insoles are prone to moisture and sweat, do not insist on polyester, switch to polyether-type recycled TPU, which is slightly more expensive but doesn’t hydrolyze and doesn’t easily collapse. Additionally, it was required that each batch measure Shore hardness, rebound, and compression set, ensure the material is fully dried before processing, and absolutely do not operate the machine if the moisture content does not meet the standard.
Kolon New Materials also taught this factory a simple trick: press a test piece each from the new material and the recycled material, then repeatedly bend and knead them by hand dozens of times. The new material shows lines quickly when bent and rebounds immediately; recycled material turns white after just two bends and rebounds more slowly, which quickly tells you the quality of the batch. Also, don’t skimp on testing: measure the Shore hardness, rebound rate, and compression set for every batch. Comparing these numbers makes it easy to tell if a batch is consistent. The feel of TPU is something that can’t be faked—it can’t fool a craftsman who works with it daily, nor can it fool feet that’ve been using it for three months.
After changing the material, complaints about the insole's rebound significantly decreased, and inventory turnover returned to normal. TPU can't fool your feet — whether the material is good or not becomes clear after three months of use. This is also why Ningbo Kolon New Materials Co., Ltd. insists on selecting recycled TPU by type and by application, rather than just shipping after quoting a low price — the feel of the material is a stage where nothing should be skimped on.
When replacing elastomers with recycled material, first check if it foams in water.
At this point, summarize the key points into a chart and follow the corresponding points—recycled TPU can reduce costs, but the premise is not to lump dried parts with water-soaked parts, polyester and polyether. Remember that mnemonic: choose polyester for dryness and wear resistance, candidate polyether for water-resistant materials, and for transparent and weather-resistant aliphatic groups—if you stick to these three lines, recycled TPU will bounce back and avoid further losses, and customers will be satisfied.
| Application Scenarios | Recommended Rating | Precautions | When Not to Use |
|---|
| Wear Resistant to Soles/Casters | Polyester Recycled TPU | For Indoor Drying | Don't Use in Water or Humidity |
| Wading Hoses/Cables | Polyether-type recycled TPU | Moisture content controlled | Recycled polyester, don't touch |
| Car film / transparent sleeve | Aliphatic recycled TPU | Watch yellowing and transparency | Regular aromatics, don't use |
| insole/cushioning foam | Foamed Recycled Shoe Material TPU | Observe Rebound and Compression Deformation | Don't Use Miscellaneous Materials |
| Phone Cases/Daily Necessities | Universal Recycled TPU | Low Cost | High Rebound Requirements, Don't Use |
| Flame-Retardant Functional Parts | Modified Recycled TPU | Check Flame Retardant Rating | Don't Use Without Certification |
Elastomer—you can tell if it's springy or not with a squeeze—if recycled material is good, step on it and squeeze twice, it's even more accurate than reading reports.
Recycled TPU, elastomer costs are reduced by grade, not gamble
Ningbo Kelong New Materials Co., Ltd. has long supplied recycled TPU thermoplastic polyurethane raw materials, covering polyester, polyether, and multiple hardness grades, used in footwear materials, car film films, tubes, seals, phone cases, and other scenarios. How much resilience remains after recycling? How to choose hardness and wear resistance? Don't try the same material on every part; if you choose the wrong type, no matter how cheap, the effort is wasted.
Statement: The brands and trademarks mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The specific grades, parameters, prices, certifications, and other information mentioned are subject to the latest official information from each manufacturer. This article does not constitute any purchasing or investment advice
