一批回收PP颗粒发到下游客户那里，货车一拆包，酸味刺鼻，客户的收货员直接拒签，司机把车停在厂门口不肯卸。改性厂老板急得团团转——回料本身有降解产生的小分子挥发物，配方里没加除味剂，等于把回收车间的味道直接打包发给了客户。
回收料的“味”和“潮”，一个靠吸附剂，一个靠分子筛，别指望一个管全部。
本文由长期经营塑料原料及助剂的宁波市科隆新材料有限公司整理，牌号与批次信息以实际供货渠道为准。
除味吸湿速查总表：管水管味各一派
除味剂和吸湿剂名字挨着，其实干的活差很远：除味剂收拾的是“气态”的异味分子，吸湿剂收拾的是“液态”的游离水。下面这张表把主流品种列清楚。
| 角色 | 代表品种 | 作用机理 | 典型用途 | 添加比例 |
|---|
| 气味吸附剂 | 沸石、活性炭、多孔硅酸盐 | 多孔结构物理吸附异味/小分子 | 回收PP/PE、再生改性料 | 0.2%-1.0% |
| 吸湿/干燥剂 | 分子筛3A/4A/5A型 | 按孔径筛分吸附水分 | 易吸水树脂、回收料干燥 | 0.1%-0.5% |
| 复合除味剂 | 植物提取物+吸附剂复配 | 吸附+遮蔽协同 | 汽车内饰级再生料 | 0.3%-2.0% |
注：以上吸附量和孔径为通用参数，实际除味效果受回料品质影响，以VOC实测为准。
图1 除味剂与吸湿剂——回收料的气味与水分净化
一个把味吸走，一个把水抽干
这位主角，是回收料的清新剂。宁波市科隆新材料有限公司长期经营各类塑料助剂及改性原料，覆盖国内外多个品牌货源，在多孔吸附除味剂、分子筛干燥剂、回收料专用除味母粒上有稳定供货渠道。而除味剂和吸湿剂这组助剂，本质上是回收塑料的“净化车间”——回收料来源杂、经历过使用和老化，料里残留着降解小分子、油脂、水分，闻着有味、用着发潮，直接做制品客户根本不收。
除味吸湿剂就像回收料的“清新剂”，把酸臭味和潮气一起收走。
除味剂的路数是“吸附+遮蔽”。沸石、活性炭、多孔硅酸盐这些材料内部全是密密麻麻的微孔，比表面积巨大，回收料里跑出来的异味小分子（醛类、酸类、烃类）一钻进孔道就被物理“关”住；植物提取物复配型再补一道“清香遮蔽”，两者一起把那股味压到鼻子闻不出来的程度。
分子筛像一把筛子，专挑小分子水往里装；除味剂像一堵海绵墙，把异味小分子按在墙上——各干各的活，谁也别越界。
吸湿剂（分子筛）的路数是“按孔大小挑水”。3A、4A、5A这些型号，其实是指微孔直径大约0.3、0.4、0.5纳米——水分子个头小，能钻进去被牢牢吸附；树脂和油分子个头大，进不去。于是它专吸水分不吸料，把回收料和易吸水树脂里的游离水抽干，从源头抑制水解和出料冒泡。
哦，你管这叫“环保再生料”？客户一拆包就闻到酸味，这是把回收车间的味道直接发给了终端。
逐品种速查：沸石活性炭吸附，分子筛管水
除味和吸湿的材料看着都像“灰色粉末”，选型却完全看孔径和用途。下面逐个讲。
除味剂这钱花得值不值，客户拆包那一秒就见分晓——鼻子比仪器诚实，也比仪器苛刻。
沸石（分子筛型吸附剂）：除味主力之一，微孔发达、热稳定性好，能扛住挤出温度，回收PP/PE改性料常用。选它的信号：要在挤出过程中同步除味、耐温的场景。注意：沸石本身是浅色粉体，深色料无所谓，浅色透明料要注意对颜色的影响；不同孔径的沸石吸附对象不同，小孔吸醛类、大孔吸烃类，复配两种孔径比单用一种覆盖更全，料太杂时尤其明显。
供货提示：多孔吸附除味剂和分子筛吸湿剂科隆新材可配套供货，每批附孔径和吸附量数据，公斤级试样支持先做VOC对比。
活性炭：吸附广谱、对有机物味效果好，但黑度太高，只能用在深色料里，浅色制品一撒就脏。选它的信号：黑色、深色回收改性料。注意：炭粉飞扬、分散要做好，否则制品表面出黑点儿。
分子筛干燥剂（3A/4A/5A型）：专管水分。回收PET、PA、PC这类易水解料，或者梅雨季节仓库返潮的粒子，挤出前加一点分子筛，把游离水吸干，出料不冒泡、不起水解。选它的信号：易吸水基材、雨季防潮。注意：分子筛吸饱了要重新活化或更换，且它只吸水，除不了味。
复合回收料除味母粒：把吸附剂和植物提取物做成母粒，分散好、加量方便，汽车内饰级再生料常用。选它的信号：低VOC、对气味等级有要求的内饰件。注意：植物提取物耐温有限，加工温度过高会分解失效。
植物提取物除味剂：靠天然植物精油或提取物做“掩蔽+吸附”双重作用，添加量低、气味清新，对醛类、酸类异味有较好的遮蔽效果，定位是环保型、低添加量的除味方案。选它的信号：对气味敏感的日用品、家居用品、儿童用品，以及不希望引入矿物粉体的浅色料。注意：植物提取物耐高温性一般，加工温度超过300℃容易分解失效，更适合200-260℃区间的PP/PE类回收料；成本比普通沸石高，通常和多孔吸附剂复配使用，吸附管治本、植物提取管治标，两头都顾到。
新车里那股塑料味，有一半来自回收料没除干净，别光怪车内装饰。
替代对照：进口除味母粒能不能换？先看这张表
做汽车内饰再生料的采购常问：进口除味母粒、进口分子筛贵，国产能不能顶？坦率说，一般包装、日用回收料的除味，国产吸附剂已够用；但汽车内饰低VOC、气味等级评价这类有严格测试的场景，仍需按气味等级和VOC实测来比。下面这张表把替代方向和验证前提列出来。
| 原用进口方向 | 典型应用 | 可对标方案 | 切换前提 |
|---|
| 进口除味母粒 | 汽车内饰再生PP/PE | 国产复合除味母粒 | 按气味等级、VOC实测平行对比 |
| 进口沸石吸附剂 | 通用回收料除味 | 国产沸石/多孔硅酸盐 | 对比除味效率、挤出后残留气味 |
| 进口活性炭 | 深色回收料除味 | 国产活性炭 | 对比吸附量、分散、黑点控制 |
| 进口分子筛3A/4A | 回收PET/PA干燥 | 国产分子筛 | 对比吸水率、活化再生、水解抑制 |
表中所列是替代方向参考，实际除味效果以VOC和气味实测为准。替代老流程：小试→气味/VOC平行测试→客户书面确认→小批量→放量。
除味剂替代要看VOC和气味等级，科隆新材寄送公斤级多孔吸附剂/分子筛试样时附孔径和吸附量数据，客户可以直接做气味等级对比和VOC检测，数据说话再放量。
除味剂加少了客户投诉，加多了成本扛不住还可能返味，量要跟着料的脏程度走。
行业场景速查：谁在跟“味”死磕
同样是除味，做普通日用品和做汽车内饰，对气味的容忍度天差地别。下面这张表按行业拆解。
| 行业 | 典型制品 | 客户最先问的参数 | 推荐方案 | 认证要求 |
|---|
| 汽车 | 再生PP内饰板、立柱饰板 | 气味等级、VOC排放 | 复合除味母粒1%-2% | 车企气味/VOC标准 |
| 家电 | 再生料外壳、抽屉 | 开箱气味、VOC | 沸石吸附剂0.5%-1% | RoHS、REACH |
| 日用 | 回收盆桶、垃圾桶 | 刺鼻酸味压味 | 吸附+遮蔽复配 | 企业内控 |
| 包装 | 再生PE/PP薄膜容器 | 异味迁移到内容物 | 食品级吸附方案 | GB 4806系列 |
| 管材板材 | 回收PP/PE卷材 | 出料烟气、水解 | 分子筛吸湿+除味 | GB/T相关标准 |
举个真实场景：做汽车再生PP内饰板、立柱饰板、门内板，客户要过主机厂的气味等级评价和VOC限值。车内空间小、密闭时间长，夏天暴晒后仪表台温度能到80℃以上，回料里残留的醛类、酸类挥发物一受热就释放出来，主机厂按标准瓶法熏样、专人评级，气味等级不达标直接退货。这种场景单靠沸石吸附往往不够，得上复合除味母粒——多孔吸附剂锁醛酸类，植物提取物补一层清香遮蔽，再配合4A分子筛把游离水吸干，添加量一般0.5%-1.5%，同时加工温度往下压个5-10℃减少降解。过不了主机厂气味测试，内饰件做得再规整也只能当废品。
添加量与搭配要点：三条对症下药
除味吸湿的量，跟着料的“脏”和“潮”程度走，别一刀切。下面三条是行业经验。
回收料有味先分两头：有味上除味，有水上吸湿，别指望一包全治。
◆ 通用回收除味：沸石或多孔硅酸盐0.3%-1.0%，把酸味油腥味压到可接受，日用包装级够用。
◆ 汽车低VOC内饰：复合除味母粒1%-2%，吸附+植物提取复配，配合低VOC基材和加工降温。
◆ 易水解/雨季防潮：分子筛0.1%-0.5%，回收PET/PA/PC挤出前吸干游离水，抑制水解冒泡。
搭配要点还有三条：一是除味和干燥要配合——料里又潮又有味，先烘干再除味，否则潮气会抢占吸附孔道、降低除味效率；二是吸附剂“吸饱就满”，别指望无限除味，料太脏时根源清洗分拣比一味加除味剂更划算；三是浅色透明料慎用深色炭粉，会污染颜色；汽车内饰选耐温够的植物提取物复配，加工高温别把有效成分烤没了；四是除味母粒的载体要和基材匹配，PP料用PE载体问题不大，但PA/PET上要选相容载体，否则母粒本身变成新的污染源。
回料：除味烘干。
有味不藏，回料才香。
加工与合规红线：这几个坑别踩
除味吸湿用不好，要么白花钱，要么把料搞脏。下面这张表把加工参数和操作后果对照列出来。
| 环节 | 参考值 | 做错的后果 |
|---|
| 先烘干再除味 | 易吸水料先80-120℃烘干 | 潮气占孔→除味效率打折 |
| 吸附剂分散 | 用母粒或充分混合 | 分散不均→局部有味、局部发花 |
| 加工温度 | 植物提取物型控温不过高 | 温度过高→有效成分分解、返味 |
| 分子筛再生 | 吸饱后活化或更换 | 失效继续用→出料冒泡水解 |
| 浅色料选材 | 浅色料选浅色吸附剂 | 炭粉污染→制品发黑发花 |
合规红线：食品接触再生制品用除味吸湿剂，迁移物要符合GB 4806系列；汽车内饰要符合主机厂气味/VOC规范；出口需符合REACH。批次COA、气味或VOC检测报告随货归档。
FAQ：回收料厂常问的五个问题
Q1：国产除味吸湿剂能不能替代进口料？
日用、包装级回收料，国产品牌已经能替代；汽车内饰低VOC、有气味等级评价的场景，建议按VOC实测和平行气味等级来比。平行测试用的对照样，科隆新材按公斤级提供，附VOC和孔径数据供对比。
Q2：加了除味剂为什么还是有味？
常见三种原因：一是料太脏，吸附孔道被占满，加再多也吸不动，得先清洗分拣；二是只除味没干燥，潮气带着挥发物一起冒；三是加工温度过高，植物提取物分解反而出味。对症查这三条。
Q3：分子筛和普通干燥剂一样吗？
原理类似但用途不同。普通干燥剂是包在袋子里吸环境水，塑料用分子筛是直接加进料里、在挤出过程中把树脂内部的游离水吸掉，耐高温、能扛挤出温度，不能拿普通干燥剂代替。
Q4：除味剂会影响材料性能吗？
少量添加通常影响不大，但吸附剂是粉体，加多了会影响力学和表面；炭粉还会污染浅色料。所以控制在0.1%-2%区间，浅色料选浅色吸附剂，是稳妥做法。
Q5：除味剂能不能管所有回收料的味？
不能。塑料回收料的味来源复杂——油脂残留、降解小分子、交叉污染都有。除味剂压得住一部分，但根本还是靠来源分拣和清洗。除味剂是“收尾”，不是“治本”。
选型三步清单：照单抓药不返工
◆ 第1步·分症状：先判断是“有味”还是“有水”——酸味油腥上除味剂，出料冒泡水解上分子筛，两者都有就复配。
◆ 第2步·看用途：日用包装选通用沸石，汽车内饰选低VOC复合除味母粒，浅色料避开炭粉；按脏潮程度定0.1%-2%用量。
◆ 第3步·先烘干再小试：易吸水料先烘干，再公斤级平行测气味/VOC和出料稳定性，过了客户书面确认再放量。
回料有没有味，客户鼻子比仪器灵
除味剂靠多孔结构吸附异味分子，吸湿剂靠分子筛吸附水分和小分子，两者常配合用于回收料改性。科隆新材供应沸石、多孔硅酸盐除味剂和3A/4A分子筛，可提供孔径分布和吸附量参考数据；不同回料（PP/PE/PA/ABS）可推荐对应体系，公斤级试样支持先做VOC和气味等级对比。
去年，一家做回收PP改性的厂，客户一拆包就嫌味大，连续三批被拒收。科隆新材给他们推荐了多孔吸附除味剂（约0.5%）+4A分子筛（约0.3%）复配，寄了公斤级样品。客户试产后，VOC检测值下降了约40%，气味等级从4级降到2级。第四批发货时，客户的收货员终于没再捂鼻子，订单恢复正常。厂长说，除味剂这钱不能省，省了它丢的是客户。
回收料一拆包有味，你除味还是只盖味？
声明：本文涉及的品牌、商标及产品名称权归各自原厂所有。本文为第三方选材知识分享，文中提及的牌号、参数、价格、认证及应用案例仅供参考，具体以各生产企业官方最新资料及批次检测报告为准。本文不构成任何采购或投资建议，读者据此操作风险自担。
A batch of recycled PP pellets was sent to downstream customers. As soon as the truck was unpacked, the sour odor was pungent, and the customer's receiving staff refused to sign for it. The driver stopped the truck at the factory gate and refused to unload. The boss of the modification plant was extremely anxious——the recycled material itself had small molecular volatiles from degradation, and no deodorizing agents were added in the formulation, which was equivalent to sending the smell of the recycling workshop directly to the customer.
The 'smell' and 'moisture' of recycled material: one is dealt with by adsorbents, the other by molecular sieves; don't expect one method to handle everything.
This article is compiled by Ningbo Kolong New Materials Co., Ltd., which has long been engaged in the business of plastic raw materials and additives. The grade and batch information are subject to the actual supply channels.
Quick Reference Table for Deodorizing and Moisture Absorption: Each one for pipe water and pipe odor
The names of deodorants and desiccants are close to each other, but what they do is actually very different: deodorants deal with 'gaseous' odor molecules, while desiccants handle 'liquid' free water. The table below lists the mainstream varieties clearly.
| Character | Representative variety | Mechanism of action | Typical uses | Add ratio |
|---|
| Odor adsorbent | Zeolite, activated carbon, porous silicate | Porous structures physically adsorb odors/small molecules | Recycled PP/PE, regenerated modified materials | 0.2%-1.0% |
| Moisture Absorbent / Desiccant | Molecular Sieve 3A/4A/5A Type | Screening adsorbed moisture by aperture | Moisture-absorbing resin, recycled material drying | 0.1%-0.5% |
| Compound Deodorizer | Plant extract adsorbent compound | Adsorption, shielding, and synergy | Automotive interior-grade recycled material | 0.3%-2.0% |
Note: The above adsorption capacity and pore size are general parameters. The actual deodorization effect is affected by the quality of the recycled material and should be based on the measured VOC.
Figure 1 Deodorants and Desiccants — Odor and Moisture Purification of Recycled Materials
One absorbs the flavor, the other sucks out the water
This main character is the refresher for recycled materials. Ningbo Kolon New Materials Co., Ltd. has been long engaged in various plastic additives and modified raw materials, covering sources for multiple domestic and international brands. It has stable supply channels for porous adsorption deodorizers, molecular sieve desiccants, and deodorizing masterbatches specifically for recycled materials. Essentially, this group of additives—deodorizers and desiccants—serves as the 'purification workshop' for recycled plastics. Recycled materials come from mixed sources and have undergone use and aging; they contain residual degraded small molecules, oils, and moisture, which smell and become damp, making them wholly unacceptable to product manufacturers if used directly.
Deodorizing desiccants are like the 'air fresheners' for recycled materials, taking away both sour odors and moisture.
The method of odor removers is 'adsorption and masking.' Materials like zeolite, activated carbon, and porous silicates are full of dense micropores, with a huge specific surface area. The small odor molecules (aldehydes, acids, hydrocarbons) coming from recycled materials get physically 'trapped' once they enter these pores. Plant extract blends add another layer of 'pleasant masking,' and together they suppress the odor to the point where it is undetectable to the nose.
The molecular sieve is like a sieve, specifically picking small water molecules to put inside; the deodorant is like a sponge wall, pressing small odor molecules onto the wall—each does its own job, and no one crosses the line.
The type of desiccant (molecular sieve) is determined by 'choosing water according to pore size.' Models 3A, 4A, and 5A actually refer to micropore diameters of approximately 0.3, 0.4, and 0.5 nanometers — water molecules are small and can enter to be firmly adsorbed; resin and oil molecules are larger and cannot enter. Therefore, it specifically absorbs moisture without absorbing the material, removing free water from recycled materials and moisture-prone resins, thereby preventing hydrolysis and foaming at the source.
Oh, you call this 'eco-friendly recycled material'? The moment the customer unpacks it, they smell a sour odor. This directly delivers the smell of the recycling workshop to the end user.
Quick reference by type: zeolite activated carbon adsorption, molecular sieve water in pipes
Materials for deodorizing and moisture absorption all look like 'gray powder,' but the selection completely depends on pore size and intended use. Let's go through them one by one.
Whether the money spent on deodorizer is worth it can be seen the moment the customer opens the package — the nose is more honest than any instrument, and also stricter than an instrument.
Zeolite (molecular sieve type adsorbent): One of the main agents for deodorization, with well-developed micropores and good thermal stability, capable of withstanding extrusion temperatures and commonly used for recycling modified PP/PE materials. Signals for choosing it: scenarios requiring simultaneous deodorization and heat resistance during extrusion. Note: Zeolite itself is a light-colored powder; it doesn't matter with dark-colored materials, but for light-colored transparent materials, pay attention to its effect on color. Zeolites with different pore sizes adsorb different targets: small pores absorb aldehydes, large pores absorb hydrocarbons. Using a combination of two pore sizes provides broader coverage than using just one, which is especially noticeable when the material is very mixed.
Supply Notice: Porous adsorption deodorants and molecular sieve desiccants can be supplied in coordination by Kelon New Materials, with pore size and adsorption capacity data attached for each batch. Kilogram-scale samples are available for preliminary VOC comparison.
Activated carbon: It has broad-spectrum adsorption and works well for odors from organic substances, but its blackness is too high, so it can only be used in dark-colored materials; sprinkling it on light-colored products will make them dirty immediately. Signals for choosing it: black or dark recycled modified materials. Note: Carbon powder is prone to flying and requires good dispersion, otherwise black spots may appear on the surface of the products.
Molecular Sieve Desiccant (Types 3A/4A/5A): Specifically absorbs moisture. Useful for recovering hygroscopic materials like PET, PA, PC, or pellets that have absorbed moisture in warehouses during the plum rain season. Add a little molecular sieve before extrusion to absorb free water, preventing bubbling and hydrolysis during discharge. Indicators for choosing it: hygroscopic substrates and moisture prevention during the rainy season. Note: Once the molecular sieve is saturated, it needs to be reactivated or replaced, and it only absorbs water, it cannot remove odors.
Compound recycled material odor-removing masterbatch: Make the masterbatch with adsorbents and plant extracts, well dispersed, convenient to add, commonly used for automotive interior-grade recycled materials. Signals for choosing it: low VOC, interior parts with odor level requirements. Note: Plant extracts have limited temperature resistance, and excessive processing temperature will cause decomposition and failure.
Plant extract deodorizer: relies on natural plant essential oils or extracts to achieve a dual effect of 'masking and adsorption.' It requires a low addition amount, has a fresh scent, and provides good masking of aldehydes and acidic odors. It is targeted as an environmentally friendly, low-addition deodorizing solution. Signals to choose it: daily necessities, household products, and children's products that are sensitive to odors, as well as light-colored materials where mineral powders are not desired. Note: the heat resistance of plant extracts is generally limited; processing temperatures exceeding 300°C can easily cause decomposition and loss of effectiveness. They are better suited for PP/PE recycled materials in the 200-260°C range; the cost is higher than ordinary zeolites, and they are usually used in combination with porous adsorbents, where adsorption addresses the root cause and plant extracts tackle surface odors, covering both aspects.
That new car plastic smell partly comes from recycled materials that weren't properly removed, so don't just blame the car's interior decoration.
Alternative Comparison: Can imported odor-removing masterbatch be replaced? First, look at this table
Common questions in purchasing recycled materials for automotive interiors: Imported odor-removing masterbatches and imported molecular sieves are expensive—can domestic products suffice? Frankly, for odor removal in general packaging and daily recycled materials, domestic adsorbents are sufficient; however, for automotive interiors with strict low-VOC and odor rating evaluations, comparison still needs to be based on actual odor ratings and VOC measurements. The table below outlines possible alternatives and the prerequisites for verification.
| Original imported direction | Typical Applications | Benchmark solution | Switch premise |
|---|
| Imported odor-removing masterbatch | Automotive interior recycled PP/PE | Domestic composite odor-removing masterbatch | Compared in parallel by odor level and actual VOC measurement |
| Imported zeolite adsorbent | General recycled material deodorization | Domestic zeolite/porous silicate | Compare deodorization efficiency and residual odor after extrusion |
| Imported activated carbon | Deodorization of dark recycled material | Domestic activated carbon | Comparison of adsorption amount, dispersion, and black spot control |
| Imported molecular sieve 3A/4A | Recycling PET/PA Drying | Domestic molecular sieve | Compare water absorption, activation regeneration, and hydrolysis inhibition |
The directions listed in the table are for reference in substitution; the actual deodorization effect should be based on measured VOC and odor. The old substitution process: small-scale test → parallel odor/VOC testing → written customer confirmation → small batch → full-scale production.
The choice of deodorant replacement depends on VOC and odor rating. When Kolon New Materials sends kilogram-scale samples of porous adsorbents/molecular sieves, they include pore size and adsorption capacity data, allowing customers to directly compare odor ratings and conduct VOC testing. Decisions can be made based on the data before scaling up.
If too little deodorizer is added, customers complain; if too much is added, the cost becomes unbearable and it may cause a residual smell. The amount should follow the level of contamination of the material.
Quick Industry Scene Check: Who Is Battling with 'Flavor' to the Death
Even when it comes to deodorization, the tolerance for odors is vastly different between ordinary household products and car interiors. The table below breaks it down by industry.
| Industry | Typical products | The parameters the customer asked about first | Recommended plan | Certification requirements |
|---|
| Car | Recycled PP interior panels, pillar trims | Odor level, VOC emissions | Compound deodorizing masterbatch 1%-2% | Automobile Industry Odor/VOC Standards |
| Home appliances | Recycled material casing, drawer | Unboxing Odor, VOC | Zeolite adsorbent 0.5%-1% | RoHS, REACH |
| Daily use | Recycling basins and trash cans | Pungent sour taste masking the flavor | Adsorption and masking compound | Corporate internal control |
| Packaging | Recycled PE/PP Film Container | Odor transfer to contents | Food-grade adsorption solution | GB 4806 Series |
| Pipes and sheets | Recycling PP/PE rolls | Discharge flue gas, hydrolysis | Molecular sieve moisture absorption and deodorization | GB/T Related Standards |
A real-life scenario: when making automotive recycled PP interior panels, pillar trims, or door panels, customers require that the products pass the OEM's odor level evaluation and VOC limits. The interior space of a car is small and sealed for long periods; in summer, after being exposed to the sun, the dashboard temperature can exceed 80°C. Aldehyde- and acid-based volatiles remaining in the recycled material are released once heated. The OEM uses the standard bottle method for fumigation tests and has dedicated personnel rate the odor. If the odor level does not meet the standard, the product is returned. In such scenarios, relying solely on zeolite adsorption is often insufficient; a composite odor-removing masterbatch is needed—porous adsorbents lock in aldehydes and acids, plant extracts add a layer of pleasant fragrance to mask odors, and 4A molecular sieves absorb free water. The addition rate is generally 0.5%-1.5%, and the processing temperature is often reduced by 5-10°C to minimize degradation. If the parts fail the OEM's odor test, no matter how neatly they are made, they can only be considered scrap.
Dosage and Key Points of Combination: Three Targeted Remedies
The amount needed for deodorizing and moisture absorption should follow the level of 'dirtiness' and 'moisture' of the material, rather than applying a one-size-fits-all approach. The following three points are industry experience.
Recycled material with odor should be handled in two ways: remove the odor if it smells, and absorb moisture if it is wet. Don't expect one package to solve everything.
◆ General odor removal for recycling: Zeolite or porous silicate 0.3%-1.0% can suppress acidic and fishy odors to an acceptable level, sufficient for daily-use packaging grade.
◆ Low-VOC automotive interior: 1%-2% composite deodorizing masterbatch, adsorption with plant extract blend, combined with low-VOC substrates and processing cooling.
◆ Easy hydrolysis / Moisture protection during rainy season: Molecular sieve 0.1%-0.5%, dry free water before extruding recycled PET/PA/PC to suppress hydrolysis bubbling.
There are three more key points for matching: First, deodorization and drying need to be coordinated — if the material is both damp and odorous, dry it first before deodorizing, otherwise moisture will occupy the adsorption channels and reduce deodorization efficiency; second, adsorbents can only hold so much, so don't expect unlimited deodorization. When the material is too dirty, cleaning and sorting at the source is more cost-effective than just adding deodorant; third, be cautious when using dark charcoal powder with light-colored transparent materials, as it can stain the color. For automotive interiors, choose plant extracts that withstand high temperatures for blending, and avoid losing the active components during high-temperature processing; fourth, the carrier of the deodorizing masterbatch must be compatible with the base material. Using a PE carrier for PP material is generally fine, but for PA/PET, a compatible carrier must be selected, otherwise the masterbatch itself can become a new source of contamination.
Recycled material: deodorizing and drying.
Flavor is not hidden; it is fragrant only when tasted again.
Processing and Compliance Red Lines: Avoid These Pitfalls
If deodorizing and moisture absorption are done poorly, you'll either waste money or contaminate the material. The table below lists processing parameters and the corresponding consequences of operations.
| link; segment; part | Reference value | The consequences of doing wrong |
|---|
| Dry first, then deodorize | Moisture-absorbent materials should be dried first at 80-120°C | Moist air occupying the hole → Decreased deodorization efficiency |
| Adsorbent Dispersion | Use masterbatch or mix thoroughly | Uneven dispersion → localized odor, localized streaking |
| Processing temperature | Plant extract type temperature control does not get too high | Excessive temperature → active ingredients decompose, off-flavor |
| Molecular sieve regeneration | Activate or replace after saturation | Continue using after failure → discharge bubbling hydrolysis |
| Selection of light-colored materials | Light-colored materials choose light-colored adsorbents | Carbon powder pollution → Products turn black and mottled |
Compliance Red Lines: Deodorizing and moisture-absorbing agents used in recycled products that come into contact with food must comply with the GB 4806 series; automotive interiors must meet the OEM odor/VOC standards; exports must comply with REACH. Batch COAs and odor or VOC test reports should be filed with the shipment.
FAQ: Five Common Questions from Recycled Material Factories
Q1: Can domestically produced odor-removing desiccants replace imported materials?
For daily use and packaging-grade recycled materials, domestic brands can already serve as replacements; in scenarios such as automotive interiors with low VOC and odor level evaluations, it is recommended to compare based on actual VOC measurements and parallel odor levels. For parallel tests, Cologne New Materials provides reference samples by the kilogram, along with VOC and pore size data for comparison.
Q2: Why is there still a smell even after adding a deodorizer?
Three common reasons: First, the material is too dirty, the adsorption pores are full, so no matter how much you add, it cannot be absorbed, and it needs to be cleaned and sorted first; second, only deodorization is done without drying, so moisture carries the volatiles out together; third, the processing temperature is too high, causing the plant extract to decompose and release odors. Check these three issues accordingly.
Q3: Are molecular sieves the same as ordinary desiccants?
The principle is similar but the uses are different. Ordinary desiccants are packaged in bags to absorb moisture from the environment, while molecular sieves for plastics are added directly into the material to absorb free water inside the resin during the extrusion process. They are heat-resistant and can withstand extrusion temperatures; ordinary desiccants cannot be used as a substitute.
Q4: Will the deodorizer affect the material performance?
Adding a small amount usually has little impact, but adsorbents are powders, and adding too much will affect the chemical and surface effects; Carbon powder can also contaminate light pigments. So keeping it in the range of 0.1%-2% and choosing light-colored adsorbents for light pigments is a prudent approach.
Q5: Can deodorizers control the odor of all recycled materials?
No. The sources of odor in recycled plastic materials are complex—oil residue, degradable small molecules, and cross-contamination. Deodorizers can suppress some of them, but fundamentally, they still rely on source sorting and cleaning. Deodorizers are the "finishing touch," not the "root cure."
Three-step selection checklist: Prepare the chemicals according to the order without redoing
◆ Step 1 · Identify symptoms: First, determine whether it is "smelly" or "watery"—apply odor remover for sour, oily, or fishy smell; apply molecular sieves for soaking and hydrolysis before discharge; mix both if present.
◆ Step 2 · Determine usage: For daily packaging, choose general-purpose zeolite products; for automotive interiors, choose low-VOC compound deodorizing masterbatches; for light colors, avoid charcoal powder; Set the dosage at 0.1%-2% based on dirt and moisture level.
◆ Step 3 · Dry first, then test for odor/VOC and discharge stability in parallel at the kilogram level. After written confirmation by the customer, increase volume.
Does recycled material have odor? Customers are more sensitive than instruments .
Deodorizer relies on its porous structure to adsorb odor molecules, while desiccants use molecular sieve to adsorb moisture and small molecules. Both are often used together for modified recycled materials. Kelong New Materials supplies zeolite, porous silicate deodorizers, and 3A/4A molecular sieves, providing reference data for pore size distribution and adsorption capacity. Different recycled materials (PP/PE/PA/ABS) can be recommended for corresponding systems; kilogram-level samples support VOC and odor grade comparisons first.
Last year, a factory specializing in recycled PP modification had a customer complain of strong odor upon unpacking, and three batches were rejected for three consecutive batches. Kolon New Materials recommended a porous adsorption deodorizer (about 0.5%) and a 4A molecular sieve (about 0.3%) blend, sending kilogram-level samples. After the customer's trial production, VOC detection dropped by about 40%, and the odor level dropped from level 4 to level 2. During the fourth batch shipment, the customer's consignee finally stopped covering their noses, and orders returned to normal. The factory manager said, "You can't cut corners on deodorizer; if you save it, you're losing the customer."
Recycled material smells as soon as you open the package—do you remove odors or just cover the smell?
Statement: The brands, trademarks, and product names mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The grades, parameters, prices, certifications, and application cases mentioned are for reference only. Please refer to the latest official information and batch inspection reports from each manufacturer. This article does not constitute any procurement or investment advice. Readers are responsible for any actions based on it
