宁波有家做家电外壳的注塑厂，产品脱模老是粘模，师傅拿气枪每模都喷外脱模剂，喷完等半天，一天下来机器空转不少，件表面还发花。后来配方里加了内加式脱模剂，料里自带脱模，不用每模喷，良率一下提上来，机台也不空转了。
塑料脱模剂这东西，外喷和内加是两条路，选对了良率和效率一起上来。先花两分钟把家底摸清。
| 体系 | 代表品种 | 关键参数 | 典型制品 | 添加比例 |
|---|
| 内加型 | 内加脱模剂母粒 | 混入料中,脱模顺 | 通用注塑件 | 0.5%-2% |
| 外喷型 | 硅酮外喷脱模剂 | 喷在模面,即用 | 复杂脱模件 | 每模喷涂 |
| 内加型 | 脂肪酸系脱模剂 | 通用,便宜 | 通用注塑 | 0.5%-1.5% |
| 内加型 | 硅酮母粒 | 爽滑耐磨,不析出 | 精密件/齿轮 | 0.5%-2% |
| 复合体系 | 内加+外喷 | 内加为主外喷补 | 难脱模件 | 按需 |
注：表中为行业通用范围，具体牌号与析出数据以厂家TDS为准。
粘模拉伤废品率高，多半是脱模方式没选对
挑料之前，先把脱模剂这件事说个明白。宁波市科隆新材料有限公司长期供应塑料脱模剂，内加式母粒、硅酮类这些常用品种有稳定货源。脱模剂说白了就是让料不粘模、件能顺利拔出来——外喷型是每模往模面上喷一层，内加型是把脱模成分混进料里，料走到哪脱模到哪。一个外挂，一个内置，用法差一截。
做注塑的厂都懂，件粘在模上拔不出来，硬拔就是拉伤、缺料，废品率一下上去。外喷看似省事，可每模都喷，等干、擦模、机台空转，一天下来产能和良率都受影响。内加式加对了，料自带脱模，不用每模喷，效率自然上来。
很多刚做注塑的有个误区，觉得脱模剂喷得越多越好。其实喷多了件表面发花，还影响印刷和粘接；内加加多了又析出。行里有句话：脱模剂是味精，提鲜就行，放多了反而坏一锅汤。按工艺下限配，上机跑一批看看脱模和表面，再微调，比一次堆上去稳得多。
再补个判断。外喷不是不能用，是别全靠它。简单件、批次稳的件，内加式一劳永逸；复杂件偶尔卡模，外喷应急补一道。全靠外喷的厂，算下来人工和机台空转的账，比内加式贵不少。干了多年的老师傅都是内加为主、外喷为辅，这样效率和质量都稳。
脱模剂是注塑的临门一脚，加对了件顺顺利利出来，加错了机台天天跟模子较劲。
图5 工人从注塑机取件
外喷即用即干，内加料自带脱模，两条路按件型选
脱模剂分两大类，别搞混。外喷型是硅酮这类，喷在模面上，料一打上去就不粘模，好处是即用即干，复杂脱模件应急好使；坏处是每模都得喷，费人工、机台空转，喷多了件表面发花还影响印刷。内加型是母粒混进料里，料走到哪脱模到哪，好处是不用每模喷，批次稳；坏处是加多了会析出、影响表面。
怎么选？件型简单、批次稳定，上内加式母粒，一劳永逸；件型复杂、偶尔难脱模，外喷补一道。老师傅都清楚，别全靠外喷——每模都喷的效率账，算下来比内加贵得多。
品种怎么挑也有讲究。脂肪酸系便宜通用，内加注塑常用；硅酮母粒爽滑耐磨，精密件和齿轮用得多，价格贵些。选的时候看制品要表面干净还是要脱模顺，再搭比例。
还有个坑得说。内加脱模剂加多了会析出，件表面冒一层，影响印刷和粘接。做外观件的厂最怕这个。这种跟别的助剂犯冲的地方，自改时一不留意就踩。
顺带说个析出的坑。外观件表面冒白霜，多半是内加脱模剂超量，或是跟色粉、阻燃剂犯冲。做外观件的厂最怕这个——一析出，印刷粘接全抓不住，整件作废。验起来不复杂：先打几件出来搁一天，再拿干净白布蹭一蹭，看有没有粉印。有粉印就是超量或配伍不对，往下降比例或换品种。这事千万别等客户退了货才想起来查，那批料早废了。
每模都喷脱模剂，喷掉的是人工和产能
厂方为什么要在脱模剂上下功夫？从车间人工说起。做注塑的厂，件粘模，师傅每模都得喷脱模剂、等干、擦模，机台空转，一天下来少出不少件。改成内加式，料自带脱模，不用每模喷，效率一下上来。脱模剂一吨料里加零点几到几个百分点，折算到吨成本里不算多。用这点钱把良率和效率提上来，账怎么算都划算。
这钱花下去，落在哪几处？落在人工和机台空转——不用每模喷，师傅腾出手盯别的；落在批次一致——件脱模顺，良率几个点往上提；也落在切换灵活——添加量小，换件型调调比例就行。
| 成本项 | 外喷型为主 | 内加式为主 | 差异说明 |
|---|
| 人工 | 每模都喷费人工 | 不用每模喷 | 师傅省一半时间 |
| 机台效率 | 喷完等干空转 | 连续打 | 产能提一截 |
| 废品率 | 拉伤发花多 | 脱模顺 | 良率差几个点 |
| 表面 | 喷多了发花 | 批次稳 | 印刷粘接牢 |
| 综合账 | 费人工空转 | 小投入提良率 | 一天多出几百件 |
自改还是买改性料？老规矩摊开比。自己买基料加内加脱模剂改，还是直接买配好的改性料？
| 对比项 | 直接买改性塑料 | 基料+脱模剂自改 | 说明 |
|---|
| 料本 | 含加工费和利润 | 通常更低 | 行业通用口径 |
| 灵活度 | 挑现成牌号 | 按件型微调 | 复杂件加量 |
| 起订量 | 整吨起 | 脱模剂袋级 | 库存压力小 |
| 合规数据 | 供应商掌握 | 自己掌握析出数据 | 表面数据在手 |
| 适合谁 | 用量小/认证严 | 有量有注塑机的厂 | 没测试能力别硬改 |
边界提醒：自己改脱模体系，得上机跑几件，看脱模顺不顺、表面析不析出，没这个设备别上来就自改。单件用量小、或者外观要求高的订单，直接买配好的料更省心。自改合不合适，跑几件再说。
成本账也核一遍。改性料的出厂价，除了原料本身，加工费、包装、管销财费一项项都加进来，末了再叠利润——通用料百分之五到十，工程料拉到百分之十五到二十五。直接买配好的脱模母粒，供应商那套加工、包装、利润全叠在料价里；自改只进基料加脱模剂，原料是大头，加工那一段省下的加价，就是自改的空间。用量稳、脱模方案跑顺了的厂，自改这笔钱才划算。
再给个直观对比。同样一吨家电外壳料，靠外喷脱模，师傅每模都喷，机台一天空转不少；按内加式母粒配齐，料自带脱模，连续打不用停。做注塑的厂都懂，机台不空转就是钱，脱模剂加对了等于在帮你抢产能。
再算笔细账。一台注塑机一天跑两千模，每模喷脱模剂要等干、要擦模，光这一下每模多花三四秒，一天下来就空转一两小时。改成内加式，料自带脱模，机台连续打不停，一天多出来的件把师傅人工都赚回来了。这一进一出，脱模剂那点成本，一天就回本。做厂的都懂，机台不空转就是真金白银，比料价那点差价实在多了。
再补个实操。脱模不是越低越顺，加多了料打滑，注塑时充模反而不稳，件还会发飘。所以上机调的时候，先看工艺要求的脱模窗口，再按窗口上下微调，别一味往上加。做注塑的老师傅都懂，脱模、充模、表面这三样是绑在一起的，动一个就得跟着看另外两个。
同一种脱模剂，放十个塑料品类里用法差出一截
脱模剂不是一张方子打天下，换个基材，体系和添加量都得调。宁波市科隆新材料给不同基材配脱模体系时，先问做什么件、脱模难不难，再推内加还是外喷——简单件内加，复杂件外喷补，问错方向配方就偏了。
| 塑料品类 | 典型场景 | 添加量范围 | 效果 | 注意事项 |
|---|
| PP | 家电外壳 | 0.5%-1.5% | 脱模干净 | 外观件防析出 |
| PE | 周转箱/桶 | 0.5%-1.5% | 脱模顺 | 通用便宜 |
| ABS | 家电外壳/玩具 | 0.5%-1.5% | 不粘模 | 注意印刷 |
| PA | 齿轮/结构件 | 0.5%-2% | 脱模耐磨 | 加工前烘干 |
| PC | 透明件 | 0.5%-1.5% | 脱模干净 | 防析出影响透光 |
| POM | 齿轮/滑块 | 0.5%-2% | 低摩擦 | 硅酮母粒 |
| PVC | 管件/型材 | 0.5%-1.5% | 脱模顺 | 配热稳定 |
| 再生料 | 回料制品 | 原配方补加 | 杂质多 | 多补一到两成 |
| 色母料 | 配色制品 | 0.5%-1% | 分散好 | 与分散剂协同 |
还有个容易漏掉的点：再生料里脱模成分已经被消耗过一轮，回料占比一过三成，原配方通常要往回补一到两成。回料掺得越多，这一项越抠不得，科隆新材配回收料体系时会把这事一并提示。
你手上要是正好有个注塑件粘模拉伤、或者外喷喷得烦，内加式怎么搭心里没底，别急着下单。把用的什么料、件有多复杂、一个月用多少发来，科隆新材先帮你把方向看一遍，圈两三个可行体系。
从每模外喷到内加自带脱模，良率账翻篇了
下面是讲清脱模逻辑拼出来的典型示例，对不上任何一家真实客户。华东有家做家电外壳的注塑厂，前几年件脱模老粘模，师傅每模都得喷外脱模剂，喷完等半天，机台空转不少，件表面还发花，良率上不去。
后来他们改成自己买PP基料，加内加式脱模母粒自改。宁波市科隆新材料有限公司给寄了公斤级样品，附了同批次析出和脱模数据。客户上机跑了平行对比，脱模顺了，不用每模喷，机台连续打，良率一下提上来。跑了三个月小批量，切过来，吨成本没涨多少，效率和良率都上来了。
他们也踩过坑。头一回内加脱模剂加多了，件表面析出，印刷不牢被退了一批；后来把内加比例往下压，再按件的复杂程度调，析出才压住。这单说明：脱模剂自改省的是料钱和人工，前提是配比别超、数据别省。
这种踩坑在注塑厂里天天上演。宁波市科隆新材料有限公司这些年接过不少类似的单子——件粘模拉伤、师傅每模外喷、机台空转，一查脱模体系没配好。把内加式按件型配足，再按析出重调比例，多数问题都能解决。脱模这事没有玄学，就是配比、件型、数据三样对不对得上。
塑料脱模剂怎么选，先看件型再翻牌号
按件型和工艺找脱模方案，对照如下：
| 应用场景 | 推荐体系 | 添加量 | 注意事项 |
|---|
| 通用户外件 | 内加式母粒 | 0.5%-1.5% | 不用每模喷 |
| 复杂脱模件 | 内加+外喷补 | 按需 | 外喷应急 |
| 精密齿轮 | 硅酮母粒 | 0.5%-2% | 耐磨低摩擦 |
| 外观件 | 内加式脂肪酸 | 0.5%-1% | 防析出 |
| PVC管件 | 内加脱模 | 0.5%-1.5% | 配热稳定 |
| 再生料>30% | 原配方补加 | 按比例 | 多补一到两成 |
采购脱模剂送个实在动作：头一回合作先要小样，要析出和脱模数据，上机跑几件典型件跑完再谈批量。脱模剂的猫腻不在单批，在两批之间析出漂不漂——每批随货带数据，比嘴上保证管用。
再补一句实操。脱模剂换供应商时，别一次全量切，先拿新样品跟老体系做平行对比，上机跑同样脱模和表面，看析出漂不漂、看脱模顺不顺，两样都稳了再换。注塑这料敏感，一次切错整批都跟着遭殃。做过注塑的都清楚，脱模剂和色粉、阻燃剂之间的配伍，换料前先在小机台上试明白，别拿大货当试验场。新配方连跑两三天没出岔子，再逐步把老库存消化掉，这是稳妥做法，图快容易出事。
车间里问得最多的几个问题，集中答一遍。问：内加式脱模剂一般加多少合适？答：总添加量百分之零点五到二，简单件取下限，复杂件取上限，加多了析出影响表面。
问：内加和外喷有什么区别？答：内加是母粒混进料里料自带脱模，外喷是每模往模面喷一层，俩是互补不是替代，长期批次稳的件上内加。问：注塑粘模先查什么？答：查三件事——脱模剂够不够、料温合不合适、模具表面清没清干净。
行情给个参照口径。按行业通用价，脂肪酸系内加脱模剂便宜，硅酮母粒贵些。整个脱模体系占吨成本也就百分之一上下——这点钱跟省下来的人工和机台空转比，真不算什么。宁波市科隆新材料有限公司报脱模剂时，会把常用品种行情和析出数据一起给你。
每模都喷脱模剂，喷掉的是师傅的人工和机台的产能；内加式加对了，件顺顺利利出来才是真省钱。
脱模体系配得对，良率和效率一起上来
宁波市科隆新材料有限公司长期供应内加式脱模母粒、硅酮类等脱模剂，覆盖PP/PE/ABS/PA等基材注塑场景。
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，文中涉及的具体牌号、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。
There is an injection molding factory in Ningbo that makes household appliance casings. The products often stuck to the mold during demolding, so the workers would spray external release agent on each mold with an air gun. After spraying, they would wait for a long time, causing the machine to idle a lot in a day, and the surface of the parts would still be uneven. Later, they added an internal release agent to the formula, so the material itself had release properties, eliminating the need to spray for each mold. As a result, the yield rate increased significantly, and the machines no longer idled.
Plastic release agents come in two approaches: external spraying and internal addition. Choosing the right one improves both yield and efficiency. First, spend two minutes to get a clear understanding of what you have.
| system | Representative varieties | Key parameters | Typical products | Add ratio |
|---|
| Internal addition type | Internal release agent masterbatch | Mixed into the material, easy to demold | General-purpose injection molded parts | 0.5%-2% |
| External spray type | Silicone external spray release agent | Spray on the mold surface and use immediately | Complex demolding part | Spray per mold |
| Internal addition type | Fatty acid-based release agent | General, cheap | General injection molding | 0.5%-1.5% |
| Internal addition type | Silicone Masterbatch | Smooth and wear-resistant, does not precipitate | Precision parts / gears | 0.5%-2% |
| Composite system | Internal coating, external spray | Primarily taken internally, supplemented with external application | Difficult-to-demold part | On demand |
Note: The table shows the general industry range; the specific grade and precipitation data are subject to the manufacturer's TDS.
The high defect rate of mold sticking and tearing is mostly due to choosing the wrong demolding method.
Before selecting materials, let's clarify the matter of release agents. Ningbo Cologne New Materials Co., Ltd. has long supplied plastic release agents, and commonly used types such as internal masterbatch and silicone have a stable supply. Simply put, a release agent allows the material not to stick to the mold, enabling the part to be removed smoothly — the external spray type involves spraying a layer onto the mold surface for each mold, while the internal type mixes the release agent into the material, so the material provides release wherever it goes. One is external, the other internal, and their usage differs significantly.
Any factory that does injection molding knows that if a part sticks to the mold and can't be removed, forcibly pulling it will cause scratches or material shortages, and the defect rate will immediately rise. External spraying may seem convenient, but if you spray every mold, wait for it to dry, wipe the mold, and let the machine idle, the daily output and yield are affected. With the right internal addition method, the material comes with its own release, so there's no need to spray each mold, and efficiency naturally improves.
Many people who are new to injection molding have a misconception, thinking that the more mold release agent you spray, the better. In fact, spraying too much can cause the surface to appear uneven and also affect printing and bonding; adding too much internally can lead to precipitation. There is a saying in the industry: mold release agent is like MSG—enough to enhance, too much can ruin the whole batch. It's much more reliable to mix according to the lower limit of the process, run a batch to see the demolding and surface condition, and then fine-tune, rather than piling it all on at once.
Add another judgment. Using external spraying is not prohibited, but you shouldn’t rely on it entirely. For simple parts or parts with stable batches, internal addition solves the problem once and for all; for complex parts that occasionally get stuck in the mold, external spraying can be used as an emergency supplement. Factories that rely entirely on external spraying end up with higher labor and machine idle costs compared to internal addition. Experienced workers, after many years, primarily use internal addition with external spraying as a supplement; this ensures both efficiency and quality.
Release agent is the final touch in injection molding; use it correctly and the parts come out smoothly, use it incorrectly and the machine struggles with the mold every day.
Figure 5 Workers taking parts from the injection molding machine
External spray dries immediately upon use, internal additive comes with self-demolding, two paths can be chosen according to the product type
Release agents are divided into two main types, don’t get them confused. The external spray type is silicone-based and is sprayed onto the mold surface; once the material is poured in, it won’t stick to the mold. The advantage is that it’s ready to use and dries immediately, making it useful for complex demolding parts in emergencies. The disadvantage is that each mold has to be sprayed, which consumes labor and causes machine idle time; spraying too much can also make the surface of the part uneven and affect printing. The internal additive type is a masterbatch mixed into the material, so wherever the material goes, it can demold. The advantage is that you don’t need to spray each mold, and batch consistency is stable; the disadvantage is that adding too much can lead to exudation and affect the surface.
How to choose? For simple parts with stable batches, add compound inside the part once and for all; for complex parts that are occasionally difficult to demold, add an external spray touch-up. Experienced workers all know not to rely solely on external spraying—if you spray every mold, the efficiency cost calculation shows it's much more expensive than adding it inside.
There are particular considerations when choosing varieties. Fatty acid-based ones are cheap and versatile, commonly used with additional injection molding; silicone masterbatches are smooth and wear-resistant, often used for precision parts and gears, and are more expensive. When selecting, consider whether the product needs a clean surface or easy demolding, and then adjust the proportion accordingly.
There’s another pitfall to mention. If too much releasing agent is added, it will precipitate, forming a layer on the surface of the part, which affects printing and bonding. Manufacturers of appearance parts fear this the most. This is the kind of conflict with other additives that can easily be encountered if you’re not careful when making modifications.
By the way, here's a pitfall related to exudation. If the surface of an appearance part has a whitish frost, it’s mostly due to excessive mold release agent added inside, or a conflict with color powder or flame retardant. Factories that make appearance parts fear this the most—once it exudes, printing and adhesion fail completely, and the whole part is scrapped. Testing it isn’t complicated: first make a few pieces and leave them for a day, then rub a clean white cloth on them to see if there’s any powder transfer. Powder transfer indicates an excessive amount or improper combination, in which case reduce the proportion or change the type. Never wait until the client returns the goods to start checking—by then that batch of material is already wasted.
Apply mold release agent to every mold; what gets wasted is labor and productivity.
Why does the factory focus on mold release agents? Let's start with the workshop workers. In plastic injection factories, when parts stick to the mold, the skilled workers have to spray mold release agent on each mold, wait for it to dry, and wipe the mold. With machines idling, you end up producing significantly fewer parts in a day. Switching to an internal additive style, where the material itself contains the mold release, eliminates the need to spray each mold, and efficiency immediately improves. Adding a small percentage of mold release agent per ton of material doesn’t add much to the cost per ton. Spending this little money to improve yield and efficiency is cost-effective no matter how you calculate it.
Where does this money go? It goes to labor and idle machine time — not needing to spray every mold, allowing the master to free his hands to focus on other things; it goes to batch consistency — smooth demolding, and a few percentage points increase in yield; it also goes to flexible switching — small additional amounts, just adjusting the proportion when changing mold types.
| Cost item | Mainly external spray type | Primarily internal addition type | Difference Explanation |
|---|
| Artificial | Each mold requires spraying manually | No need to spray every mold | The master saves half the time |
| Machine efficiency | After spraying, wait for it to dry before idling | Continuous hitting | Increase production capacity by a notch |
| Defect rate | Sprain often becomes mottled | Demolding parting | The yield rate is a few points lower |
| surface | Spraying too much causes uneven coloration | Batch stable | Printing adhesion is strong |
| General account | Wasting manpower | Small investment improves yield rate | A few hundred more pieces a day |
Modify it yourself or buy modified material? As usual, let's compare. Should you buy the base material and add internal additives and release agent yourself, or just buy the pre-prepared modified material?
| Comparison item | Buy modified plastic directly | Base material release agent self-modified | Explanation |
|---|
| material cost | Including processing fees and profit | Usually lower | Industry standard caliber |
| Flexibility | Choose an existing brand/model | Fine-tune by item type | Increase the quantity of complex parts |
| Minimum order quantity | Starting from a whole ton | Release agent bag grade | Low inventory pressure |
| Compliance data | Supplier Mastery | Control the precipitation data yourself | Having the surface data in hand |
| Suitable for whom | Small dosage / Strict certification | A factory with both volume and injection molding machines | If you don't have testing ability, don't force changes. |
Border reminder: If you modify the demolding system yourself, you need to run a few pieces on the machine to see if demolding is smooth and if the surface precipitates. Without this equipment, don’t just modify it on your own. For orders with small single-piece usage or high appearance requirements, buying pre-prepared material is more convenient. Whether self-modification is suitable or not, test a few pieces first before deciding.
Also check the cost accounts. For the ex-factory price of modified materials, in addition to the raw materials themselves, processing fees, packaging, and administrative and financial expenses are all included item by item, and finally profit is added—5% to 10% for general materials, 15% to 25% for engineering materials. If buying pre-mixed release masterbatch directly, the supplier’s processing, packaging, and profit are all included in the material price; if modifying it yourself, you only add the base material and release agent, with raw materials being the main cost. The savings from skipping the processing markup is where your modification margin comes in. For factories with stable usage and a well-tested release scheme, modifying it yourself is only cost-effective if it makes financial sense.
Here's another intuitive comparison. For the same ton of appliance shell material, relying on external mold release spraying requires the operator to spray each mold, and the machine idles for a lot of time each day; with internally added masterbatch, the material comes with its own mold release, so it can run continuously without stopping. Factories that do injection molding all understand that machine idle time is money, and using the right mold release is like helping you seize production capacity.
Let's do the math carefully. An injection molding machine produces two thousand molds a day. For each mold, spraying mold release agent requires waiting for it to dry and wiping the mold. Just this process adds three to four seconds per mold, which adds up to one or two hours of idle time per day. If switched to an internal additive type, where the material itself has mold release, the machine can run continuously without stopping, and the extra output in a day can cover the operator's labor costs. This input and output means that the small cost of mold release covers itself in a day. Anyone in manufacturing knows that keeping machines running, not idle, is real money, far more substantial than the small difference in material costs.
Let's add a practical tip. Demolding is not smoother the lower it is; adding too much material can cause slipping, and during injection molding, filling the mold may become unstable, causing the parts to be uneven. Therefore, when adjusting on the machine, first check the demolding window required by the process, then make slight adjustments up or down according to the window—don’t just keep increasing it. Experienced injection molding workers all know that demolding, mold filling, and surface quality are interconnected; adjusting one requires paying attention to the other two.
The same type of release agent behaves quite differently when used in ten different types of plastic products.
Release agent is not a one-size-fits-all solution; if the base material changes, the system and dosage must be adjusted. When Ningbo Kolon New Materials formulates release systems for different base materials, they first ask what part is being made and whether demolding is difficult, then recommend internal addition or external spraying—simple parts get internal addition, complex parts get external spraying as a supplement. Asking the wrong question can lead to an off-target formulation.
| Plastic products | Typical scenario | Addition range | Effect | Precautions |
|---|
| PP | Home appliance casing | 0.5%-1.5% | Demold cleanly | Appearance parts anti-precipitation |
| PE | Turnover box/barrel | 0.5%-1.5% | Easy demolding | Generic and cheap |
| ABS | Home appliance casing / toys | 0.5%-1.5% | Non-stick mold | Attention: Printing |
| PA | Gears/Structural Parts | 0.5%-2% | Release and wear-resistant | Drying before processing |
| PC | transparent part | 0.5%-1.5% | Demold cleanly | Prevent precipitation from affecting light transmission |
| POM | Gear/Slider | 0.5%-2% | Low friction | Silicone Masterbatch |
| PVC | Pipe Fittings/Profiles | 0.5%-1.5% | Easy demolding | thermally stable |
| Recycled material | Recycled Material Products | Supplement the original formula | Many impurities | Add one to two more parts |
| Color masterbatch | Color-matching products | 0.5%-1% | Disperse well | Synergistic with dispersant |
There's another point that's easy to overlook: the release agent components in recycled material have already been used once. When the recycled content exceeds 30%, the original formulation usually needs to be supplemented by 10-20%. The more recycled material is mixed in, the less you can skimp on this. When Kolon New Materials formulates a recycled material system, they will point this out as well.
If you happen to have an injection-molded part that sticks to the mold and gets scratched, or the external spraying is troublesome, and you're unsure about how to set up the internal addition method, don't rush to place an order. Send over the material you're using, how complex the part is, and how much you use per month. Cologne New Materials will first help you review the options and circle two or three feasible systems.
Spraying from the outside of each mold to adding built-in demolding inside, the yield account has turned over.
Below is a typical example demonstrating the demolding logic put together, which does not correspond to any real customer. There is an injection molding factory in East China that makes household appliance casings. A few years ago, the parts always stuck during demolding, and the master had to spray release agent on each mold. After spraying, he had to wait for a long time, and the machine idled quite a bit, yet the surface of the parts still had mottling, and the yield could not improve.
Later, they changed to buying PP base material themselves and modifying it with added internal release agent masterbatch. Ningbo Kolon New Materials Co., Ltd. sent kilogram-level samples along with precipitation and release data from the same batch. The customer ran parallel comparisons on the machine; the release process became smooth, and they no longer had to spray each mold. Continuous production on the machine improved yield significantly. After running small batches for three months, when switching over, the cost per ton didn't increase much, but both efficiency and yield improved.
They have also encountered pitfalls. The first time they added too much internal release agent, it came out on the surface of the parts, the printing didn't stick, and a batch was rejected; later, they reduced the amount of internal addition and then adjusted according to the complexity of the parts, only then was the release properly controlled. This case shows: saving on release agent by adjusting yourself saves on material and labor costs, but the premise is that the ratio should not be exceeded and the data should not be skimped on.
This kind of pitfall happens every day in injection molding factories. Ningbo Kolong New Materials Co., Ltd. has handled quite a few similar orders over the years—pieces sticking to molds and getting scratched, operators spraying outside each mold, machines idling. Upon inspection, the demolding system was not properly configured. By adjusting the internal additive according to the type of piece, and then readjusting the ratio according to the release, most problems can be solved. Demolding is not mystical; it just comes down to whether the ratio, piece type, and data match up.
How to choose a plastic release agent: first look at the part type, then choose the grade.
Find demolding solutions according to the type of part and process, as shown below:
| Application scenario | Recommendation system | Addition amount | Precautions |
|---|
| General Outdoor Parts | Internal additive masterbatch | 0.5%-1.5% | No need to spray every mold |
| Complex demolding part | Internal addition, external spray补 | On demand | External Spray Emergency |
| Precision gear | Silicone Masterbatch | 0.5%-2% | Wear-resistant and low friction |
| Exterior parts | Internal additive fatty acid | 0.5%-1% | Prevent sedimentation |
| PVC fittings | Apply mold release internally | 0.5%-1.5% | Thermally stable |
| Recycled material >30% | Supplement the original formula | Proportionally | Add one to two more parts |
A practical action for purchasing release agent: For the first cooperation, start with a small sample, check the extraction and release data, run a few typical pieces on the machine, and only then discuss bulk orders. The trick with release agents isn’t in a single batch, but in whether it floats between two batches—each batch should come with data, which is more reliable than verbal promises.
One more practical tip. When changing suppliers for mold release agents, don’t switch everything at once. First, take the new sample and do a parallel comparison with the old system. Run it on the machine with the same demolding and surface conditions to see if it precipitates or floats, and to check if demolding is smooth. Only switch completely once both are stable. Injection molding materials are sensitive, and if you make a wrong switch at once, the whole batch will be affected. Anyone who has done injection molding knows that the compatibility between mold release agents, colorants, and flame retardants is crucial. Test it on a small machine before changing the material; don’t use mass production as a test bed. If the new formulation runs smoothly for two to three days without issues, then gradually use up the old inventory. This is the safe approach; trying to rush can easily cause problems.
Here are answers to the few most frequently asked questions in the workshop. Question: How much internal mold release agent is generally appropriate? Answer: The total addition should be 0.5% to 2%. Use the lower limit for simple parts and the upper limit for complex parts. Adding too much can cause precipitation and affect the surface.
Q: What is the difference between internal additive and external spray? A: Internal additive is when the masterbatch is mixed into the material, which brings its own release properties. External spray is when a layer is sprayed onto the mold surface for each mold. The two are complementary, not substitutes. For parts with stable long-term production batches, use internal additive. Q: What should be checked first when injection molding sticks to the mold? A: Check three things—whether there is enough release agent, whether the material temperature is appropriate, and whether the mold surface is clean.
Provide a reference for the market price. According to the industry standard price, adding a release agent to fatty acids is cheaper, while silicone masterbatch is more expensive. The entire release system only accounts for about one percent of the cost per ton—this amount of money is really nothing compared to the labor saved and machine idle time. When Ningbo Cologne New Materials Co., Ltd. quotes a release agent, they will provide you with both the market price of common types and the precipitation data.
Applying release agent to every mold wastes the labor of the skilled worker and the machine's production capacity; if the internal addition is done correctly, parts come out smoothly, which is the real way to save money.
When the demolding system is properly matched, both yield and efficiency improve together.
Ningbo Cologne New Materials Co., Ltd. has long been supplying internal release-agent masterbatches and silicone-based release agents, covering injection molding applications for PP/PE/ABS/PA and other substrates.
Statement: The brands and trademarks mentioned in this article are owned by their respective manufacturers. This article is a third-party material selection knowledge sharing, and the specific grades, parameters, prices, certifications, and other information mentioned in the text are subject to the latest official information from the manufacturers. This article does not constitute any procurement or investment advice.
