注塑车间里，师傅每开一模都要拿铜铲撬件，撬慢了下一模就打不满。一天下来撬坏了七八个件，模具表面还被刮出一道划痕，修模花了两千多。配方师调了半天，发现外润滑剂硬脂酸钙只加了0.1%，内润滑PE蜡加了0.6%——料在料筒里倒是流得欢，到了模壁就粘住不走。
润滑剂加少了塑料粘模喊难，加多了制品喷霜掉粉，都是没找准那个平衡。
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。
润滑剂速查总表：内润滑与外润滑两本账
做润滑要先分清“对内”还是“对外”。内润滑钻进熔体里降粘度、改善流动；外润滑跑到模壁和金属表面形成隔离层、防粘模。下面这张表把常用品种的定位和用量列清楚。
| 类型 | 代表品种 | 主要作用 | 典型用途 | 添加比例 |
|---|
| 内润滑 | PE蜡、EBS | 降熔体粘度、促流动 | 挤出造粒、高填充 | 0.2%-0.6% |
| 外润滑 | 硬脂酸钙、硬脂酸锌 | 防粘金属壁、离模 | 注塑脱模、表面光洁 | 0.1%-0.3% |
| 复合润滑 | 内外复配母粒 | 内外兼顾、好分散 | PP/PE改性通用 | 总0.5%-0.8% |
| 特种润滑 | 硅酮母粒 | 超顺滑、耐磨 | 长效润滑、爽滑 | 0.5%-2% |
注：以上参数为行业通用范围，具体熔点、粘度和酸值以生产企业官方产品手册及批次报告为准。思路是先判断你缺的是“流动”还是“离模”，再决定补内还是补外。
图1 润滑剂——熔体与模壁之间的顺滑之界
润滑剂不是越多越滑，内外平衡才是关键
把主角请出来认识一下。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，在润滑剂、分散剂、加工助剂等品类上有稳定供货渠道。而润滑剂这个品类，是注塑机里的“润滑油”——塑料熔体在螺杆和模腔里流动时，既要和螺杆、料筒内壁摩擦，又要在冷却后顺利脱离模面。内润滑负责钻进熔体内部，降低分子间摩擦、改善流动性；外润滑负责迁移到金属表面，形成一层隔离膜，让制品顺利脱模、表面光洁。
润滑剂就是注塑机里的润滑油：内润滑给料松绑，外润滑给模壁让路。
两者的分工像开车：内润滑是把发动机里的机油换好，让机件转得轻快；外润滑是在车门密封条上涂点蜡，让开关不卡。一个在内部降阻力，一个在表面做隔离，缺一不可。内润滑不足，熔体粘度高、流动费劲，剪切热一大材料还容易降解；外润滑不足，熔体粘模、制品表面粗糙、脱模顶白。所以行业常说“PE蜡做内、硬脂酸钙做外”，两者搭着用，总量控制在0.5%到0.8%左右，是通用平衡点。
内润滑是料堆里的润滑剂，外润滑是模壁上的隔离霜，里外不是一回事。
很多新手以为润滑剂是“锦上添花、加点无害”，其实超量后患很大。润滑剂本身是低分子或蜡状物，加多了会从制品内部迁移到表面，形成“喷霜”——一层白白的粉末或油雾，表面发雾、印刷涂装附着力下降；更麻烦的是做超声波焊接或涂装的件，析出的润滑剂会让焊接强度和涂层附着力明显掉下来。所以“平衡”二字，不是审美，是性能红线。
表面麻点粘模就怪设备？先看看你的外润滑是不是少加了0.1%。
逐品种速查：PE蜡管内流，硬脂酸钙管外离，硅酮管长效
润滑剂品种看着多，抓住几个主力就能覆盖八成改性。每个品种都讲清定位、什么信号该用、用的时候避开什么。
内润滑和外润滑是跷跷板的两头，压下这头就翘起那头，配方师的活儿就是找那个平衡点。
PE蜡（聚乙烯蜡）：内润滑主力，降低熔体粘度、改善分散和流动，高填充配方里还兼帮忙分散填料。选它的信号：挤出造粒、高填充、需要降粘促流动。注意：PE蜡偏内润滑，单用可能脱模不够，常配硬脂酸钙。
供货提示：PE蜡和硬脂酸钙是润滑体系的基础组合，科隆新材可配套供货，每批附熔点和粘度数据，公斤级试样支持先调配方再批量。
硬脂酸钙（锌）：外润滑主力，迁移到金属表面防粘模、帮助离型，也是常用的卤素吸收剂。选它的信号：注塑脱模、需要表面光洁、防粘模。注意：硬脂酸钙用量偏多会析出喷霜，且影响透明件透光。
EBS（乙撑双硬脂酸酰胺）：润滑分散双效品，既降粘度又帮颜料填料分散，色母粒里常见。选它的信号：做色母、高填充、需要润滑兼顾分散。注意：EBS也会迁移，涂装印刷件要控制用量。
润滑剂省下的是脱模那点事，赔上的可能是整批焊接和涂装——这笔账怎么算都不划算。
硅酮母粒：以硅氧烷为有效成分的母粒，超顺滑、耐磨、耐刮，价格带约25到45元/kg。选它的信号：做需要爽滑手感、耐磨静音的件，长期润滑。注意：硅酮迁移强，做印刷、涂装、粘接的件要慎用，否则移印发花、涂层掉。
复合润滑剂（内外复配母粒）：把内、外润滑按比例预配好，直接添加、分散方便，PP/PE改性通用。选它的信号：配方求稳、不想自己调比例。注意：复合母粒比例固定，特殊工况仍要微调。
替代对照：进口润滑能不能换？先看这张表
采购常问：进口PE蜡、硬脂酸钙、硅酮母粒能不能用国产替代？答案是可以，但要注意润滑效率和析出行为的批次差异。润滑剂是“手感型”助剂，光看指标不够，还得上机试脱模和表面。替代方向和上机前提，都在下表里。
| 原用进口方向 | 典型应用 | 可对标方案 | 切换前提 |
|---|
| 进口PE蜡 | 挤出/高填充降粘 | 国产PE蜡 | 小试对比熔融粘度、分散性、析出 |
| 进口硬脂酸钙 | 脱模/防粘模 | 国产硬脂酸钙 | 对比脱模效果、透明件透光、析出量 |
| 进口EBS | 色母分散润滑 | 国产EBS | 对比分散性、润滑平衡、印刷附着 |
| 进口硅酮母粒 | 爽滑耐磨 | 国产硅酮母粒 | 对比爽滑度、耐磨、迁移/印刷影响 |
这张表解决的是“换谁”的问题，换完顺不顺还得上机见。替代要上机试脱模、看表面、测焊接涂装附着，别只看TDS。
润滑剂的替代效果要靠上机调比例验证，科隆新材寄送公斤级试样时附熔点和粘度参数，客户可以直接在注塑机上对比粘模和喷霜情况，不用盲调。
一喷霜就换料？先把PE蜡和硬脂酸钙的比例调一遍再说。
行业场景速查：不同制品对润滑的要求差在哪
同样是润滑剂，做普通注塑件和做要喷漆丝印的件，要求完全不同。按行业拆开看要求差在哪，下表一目了然。
| 行业 | 典型制品 | 客户先问的参数 | 推荐体系 | 注意 |
|---|
| 通用改性 | PP/PE注塑件 | 脱模顺畅、表面光洁 | PE蜡+硬脂酸钙 总0.5-0.8% | 控制总量防喷霜 |
| 汽车 | 内饰件、门板 | 低VOC、可焊接涂装 | 低析出润滑、减量 | 焊接涂装要压润滑 |
| 色母/高填充 | 色母粒、填充母粒 | 分散+流动 | EBS/PE蜡兼顾 | 关注迁移 |
| 薄膜/型材 | PP型材、片材 | 表面光泽、析出 | 复合润滑母粒 | 透明件选透明级 |
| 耐磨件 | 齿轮、滑块、静音件 | 长效耐磨爽滑 | 硅酮母粒 | 慎用印刷涂装件 |
举个具体场景：做汽车门板，要后续喷漆和超声波焊接，润滑剂就得往下压，优先低析出品种，否则喷漆缩孔、焊接强度不够。这种件宁可脱模稍费点事，也不能让润滑剂析出坏事。
添加量与搭配要点：四个通用配方记住就够了
润滑剂的添加和搭配有规律，不用每次从零试。四个通用配方覆盖了主流做法。
PE蜡配硬脂酸钙，内松外离，那个平衡点不是报表算出来的，是在机台上一模一模试出来的。
◆ 通用PP/PE注塑：PE蜡（内，0.3%-0.5%）+ 硬脂酸钙（外，0.1%-0.3%），总0.5%-0.8%，兼顾流动和脱模。
◆ 高填充/色母：EBS或PE蜡（0.5%-2%），润滑兼分散，帮颜料填料化开。
◆ 汽车焊接涂装件：低析出润滑并减量，焊接强度和涂装附着优先。
◆ 耐磨静音件：硅酮母粒（0.5%-2%），长效爽滑耐磨，避开印刷涂装位。
最后补三条提醒：一是内、外润滑要同时调，单加一边会失衡——只加内润滑脱模差，只加外润滑料流粘；二是做焊接、涂装、丝印、粘接的件，润滑剂总量从严，析出会直接拖后腿；三是润滑剂和分散剂常共用EBS/PE蜡，别重复叠加导致超量。
做焊接件和涂装件，润滑剂总量往下压，别贪那点滑。
润滑：内外平衡。
加工与合规红线：这五个坑别踩
润滑用不好，不是粘模就是喷霜。关键环节和做错的后果见下表。
| 环节 | 参考值 | 做错的后果 |
|---|
| 内外比例 | 内0.3-0.5%、外0.1-0.3% | 失衡→脱模差或料流粘 |
| 总量控制 | 总0.5%-0.8%，特殊另调 | 超量→喷霜、焊接涂装下降 |
| 混合分散 | 与树脂充分预混 | 不均→局部析出、表面花 |
| 透明件 | 选透明级润滑 | 用错→透光率下降、发雾 |
| 焊接涂装件 | 润滑剂减量或低析出 | 析出→缩孔、附着力差 |
合规红线：食品接触用润滑剂要符合GB 4806或FDA相关条款；硅酮母粒在部分迁移测试中有要求；出口欧盟核对REACH。焊接、涂装、丝印类制件，润滑析出往往是客户投诉的重灾区，务必在小试阶段就做附着和析出测试。
FAQ：车间与采购常问的六个问题
Q1：国产润滑剂能不能替代进口料？
可以。PE蜡、硬脂酸钙、EBS这类通用润滑剂，国产主流牌号差距已经很小，上机试脱模和表面即可；硅酮母粒在长效爽滑和迁移控制上，进口仍有一定优势。正确做法是拿公斤级样品上机对比脱模、表面、析出和焊接涂装附着，通过后再小批量放量。上机对比要用的试样和基准料，科隆新材可按公斤级配齐，附熔点、粘度参数。
Q2：制品表面喷霜发白，是润滑剂加多了吗？
很可能是。润滑剂超量会迁移到表面形成白霜。先降润滑剂总量，再检查内外比例；如果是透明件，看看是不是选了析出大的硬脂酸类。
Q3：内润滑和外润滑到底怎么分？
简单记：PE蜡、EBS偏内，钻进熔体降粘度促流动；硬脂酸钙/锌偏外，迁到金属壁防粘模助脱模。实际配方常两者搭配，找那个平衡点。
Q4：为什么我的件焊接不上、喷漆掉？
先怀疑润滑剂。润滑析出会削弱焊接面和涂层附着。把润滑剂减量或换低析出品种，再做焊接强度和百格附着测试。
Q5：硅酮母粒为什么不能随便用？
硅酮迁移强、手感滑，但它会让印刷、涂装、粘接发花或掉附。需要后工序的件要避开，纯耐磨静音件才适合。
Q6：润滑剂和分散剂是不是一回事？
不是一回事，但EBS、PE蜡常常身兼两职——既润滑又帮分散。配方里要统筹算量，别把两者叠加到超量。
选型三步清单：照着做不踩坑
◆ 第1步·看症状：先分清是“流不动”还是“脱不出”——流不动补内润滑PE蜡，脱不出补外润滑硬脂酸钙。
◆ 第2步·定总量：按内外比例定总用量0.5%-0.8%，焊接涂装印刷件从严减量，耐磨件上硅酮母粒。
◆ 第3步·上机验：小试必做脱模、表面、析出、焊接/涂装附着四项，合格再放量，并索取批次报告归档。
不粘模、不喷霜，润滑平衡靠数据调
润滑剂的核心是内外平衡——内润滑降粘度、外润滑防粘模，哪头多了都出事。科隆新材供应PE蜡、EBS、硬脂酸盐等润滑剂时，可提供熔点、粘度、酸值等关键参数，帮助客户快速定位内外润滑比例；对粘模或喷霜问题，可按公斤级寄送不同品类试样做对比调试。
去年春天，一家做PP家电外壳的注塑厂被粘模问题折磨了一个月——每模都要撬，报废率约5%，模具还刮花了。科隆吴经理看了他们的配方，PE蜡加了0.8%，硬脂酸钙只有0.1%，明显外润滑不足。他建议把PE蜡降到0.4%、硬脂酸钙提到0.3%，并寄了对应样品。客户调完当天，粘模就基本消失了，报废率降到约0.5%。车间师傅说，终于不用再跟铜铲过日子了。
你的PE蜡和硬脂酸钙，比例是几比几？
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。
In the injection molding workshop, every time the master opens a mold, he has to use a copper spatula to pry the parts; if he pries too slowly, the next mold won't fill completely. By the end of the day, seven or eight parts were damaged from prying, and a scratch was left on the mold surface, which cost more than two thousand to repair. After the formulator adjusted for a long time, he found that the external lubricant calcium stearate was only added at 0.1%, and the internal lubricant PE wax was added at 0.6%—the material flowed well in the barrel, but stuck to the mold wall and wouldn't move.
Adding too little lubricant makes the plastic stick to the mold and is difficult, while adding too much causes the product to have blooming and powdering. Both are due to not finding the right balance.
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 Lubricants: Separate Accounts for Internal and External Lubrication
For lubrication, you must first distinguish between 'internal' and 'external.' Internal lubrication penetrates the melt to reduce viscosity and improve flow; external lubrication moves to the mold walls and metal surfaces to form a barrier and prevent sticking. The table below clearly lists the positioning and dosage of commonly used types.
| Type | Representative variety | Main function | Typical uses | Add ratio |
|---|
| Internal lubrication | PE wax, EBS | Reduce melt viscosity, promote flow | Extrusion granulation, high filling | 0.2%-0.6% |
| External lubrication | Calcium stearate, zinc stearate | Prevent sticking to metal walls, demold | Injection molding demolding, surface finish | 0.1%-0.3% |
| Composite lubrication | Inner and outer compounded masterbatch | Consider both internal and external aspects, and diversify well | Modified PP/PE General Purpose | Total 0.5%-0.8% |
| Specialty Lubrication | Silicone Masterbatch | Super smooth and wear-resistant | Long-lasting lubrication, smooth | 0.5%-2% |
Note: The above parameters are general industry ranges. The specific melting point, viscosity, and acid value should be based on the official product manual and batch report from the manufacturer. The approach is to first determine whether you lack 'flow' or 'demolding', and then decide whether to add internally or externally.
Figure 1 Lubricant — the boundary of smoothness between the melt and the mold wall
Lubricant doesn't become smoother the more you use; the key is internal and external balance.
Let's invite the protagonist out to get acquainted. Ningbo Kolon New Materials Co., Ltd. has been long engaged in the business of various plastic additives and modified raw materials, covering multiple domestic and international brand sources. It has stable supply channels in categories such as lubricants, dispersants, and processing aids. The lubricant category, in particular, is the 'engine oil' for injection molding machines — when the plastic melt flows in the screw and mold cavity, it needs to both rub against the screw and barrel walls and also release smoothly from the mold after cooling. Internal lubrication penetrates the melt, reducing intermolecular friction and improving flowability; external lubrication migrates to the metal surface, forming a protective layer that allows the product to release smoothly and have a smooth surface.
Lubricant is like the lubricating oil in an injection molding machine: internal lubrication loosens the feed, while external lubrication clears the way for the mold wall.
The division of labor between the two is like driving a car: internal lubrication is like changing the engine oil to make the engine parts turn smoothly; external lubrication is like applying some wax to the car door seals to prevent sticking. One reduces resistance internally, the other provides surface isolation, and both are indispensable. Without enough internal lubrication, the melt viscosity is high, flow is difficult, and with shear heat, the material can easily degrade; without enough external lubrication, the melt sticks to the mold, the product surface becomes rough, and demolding can leave marks. Therefore, the industry often says 'PE wax for internal, calcium stearate for external.' Using both together, with a total amount controlled at about 0.5% to 0.8%, is the general balance point.
Internal lubrication is the lubricant in the material pile, while external lubrication is the release agent on the mold wall; inside and outside are not the same thing.
Many beginners think that lubricants are 'a nice extra, harmless to add,' but actually, excessive amounts can cause serious problems. Lubricants themselves are low-molecular or waxy substances, and adding too much can cause them to migrate from the inside of the product to the surface, forming 'blooming'—a layer of white powder or oil mist, which makes the surface hazy and reduces the adhesion of printing and coatings. What's even more troublesome is that for parts undergoing ultrasonic welding or coating, the exuded lubricant can significantly reduce welding strength and coating adhesion. Therefore, the word 'balance' is not just about aesthetics; it is a performance red line.
Blaming the equipment for surface pitting sticking to the mold? First, check if you added 0.1% less external lubricant.
Quick reference by type: PE wax flows inside the tube, calcium stearate separates outside the tube, silicone tube is long-lasting
There seem to be many types of lubricants, but focusing on a few main ones can cover 80% of modifications. For each type, clearly explain its positioning, what signals it should be used for, and what to avoid when using it.
Internal lubrication and external lubrication are the two ends of a seesaw; pressing down on one end lifts the other. A formulator's job is to find that balance point.
PE Wax (Polyethylene Wax): The main internal lubricant, reduces melt viscosity, improves dispersion and flow, and also helps disperse fillers in high-filler formulations. Indicators for choosing it: extrusion granulation, high filler content, need to reduce viscosity and promote flow. Note: PE wax is biased towards internal lubrication, and using it alone may not provide enough release; it is often paired with calcium stearate.
Supply Notice: PE wax and calcium stearate are the basic combination of the lubrication system. Kolon New Materials can supply them in matching sets, with each batch accompanied by melting point and viscosity data. Kilogram-scale samples support formula adjustment before bulk production.
Calcium (zinc) stearate: the main external lubricant, migrates to the metal surface to prevent mold sticking and aid release, and is also a commonly used halogen scavenger. Signals for choosing it: injection molding release, need for smooth surface, anti-stick mold. Note: excessive amounts of calcium stearate can cause blooming and affect the light transmittance of transparent parts.
EBS (Ethylene Bis-Stearamide): A dual-function lubricating and dispersing agent, it both reduces viscosity and helps disperse pigments and fillers, commonly seen in color masterbatches. Signals for choosing it: making masterbatches, high loading, needing lubrication while also considering dispersion. Note: EBS can also migrate, so the amount should be controlled in coated and printed items.
The lubricant only saves the little issue of demolding, but what you might lose could be the entire batch of welding and painting – no matter how you calculate it, it's not worth it.
Silicone Masterbatch: Masterbatch with siloxane as the active ingredient, ultra-smooth, wear-resistant, and scratch-resistant, with a price range of about 25 to 45 CNY/kg. Signals for choosing it: used for parts that require a smooth touch, wear resistance, and quiet operation, providing long-term lubrication. Note: Silicone has strong migration; be cautious when used for printing, coating, or bonding parts, otherwise it can cause ghosting in pad printing or coating peeling.
Compound lubricant (internal and external compounded masterbatch): Pre-mix the internal and external lubricants in the right proportion, easy to add and disperse directly, suitable for PP/PE modification. Signals for choosing it: formulation stability is desired, and you don’t want to adjust the proportions yourself. Note: the proportion of the compound masterbatch is fixed, special conditions still require fine-tuning.
Alternative comparison: Can imported lubricants be replaced? First, look at this chart
Common Procurement Question: Can imported PE wax, calcium stearate, and silicone masterbatch be replaced with domestic alternatives? The answer is yes, but attention must be paid to batch differences in lubrication efficiency and exudation behavior. Lubricants are "touch-feel" type additives; just looking at the specifications is not enough—you also need to test them on the machine for demolding and surface quality. The directions for substitution and the prerequisites before on-machine testing are listed in the table below.
| Original imported direction | Typical applications | Benchmark solution | Switch premise |
|---|
| Imported PE Wax | Extrusion/High-Filling Viscosity Reduction | Domestic PE Wax | Preliminary test comparing melt viscosity, dispersibility, and precipitation |
| Imported calcium stearate | Demolding / Anti-stick mold | Domestic calcium stearate | Compare demolding effect, light transmission of transparent parts, and precipitation amount |
| Imported EBS | Color masterbatch dispersion lubrication | Domestic EBS | Comparison of dispersion, lubrication balance, and printing adhesion |
| Imported silicone masterbatch | Smooth and wear-resistant | Domestic silicone masterbatch | Compare smoothness, wear resistance, migration/printing impact |
This table addresses the question of 'who to replace.' After replacement, whether it works smoothly still needs to be verified on the machine. Substitutes must be tested on the machine for demolding, surface inspection, and welded/coating adhesion testing—don't just rely on the TDS.
The substitutive effect of the lubricant needs to be verified by adjusting the ratio on the machine. When Colong New Materials sends kilogram-level samples, they include the melting point and viscosity parameters. Customers can directly compare mold sticking and frosting on the injection molding machine without adjusting blindly.
Change the material every time you spray the frosting? Adjust the ratio of PE wax to calcium stearate first before talking about that.
Quick Industry Reference: How lubrication requirements differ for various products
Even though both are lubricants, the requirements are completely different for making ordinary injection-molded parts and for making parts that need to be painted or screen-printed. Looking at the requirements broken down by industry, the differences are clear in the table below.
| Industry | Typical products | The parameters the client asked about first | Recommendation system | Attention |
|---|
| General Modification | PP/PE injection molded parts | Smooth demolding, glossy surface | PE wax Calcium stearate Total 0.5-0.8% | Total volume control anti-spray cream |
| Car | Interior parts, door panels | Low VOC, weldable coating | Low deposition lubrication, reduced quantity | Welding and coating must be pressed and lubricated |
| Color masterbatch / High filling | Color masterbatch, filler masterbatch | dispersed flow | EBS/PE wax balancing both | Attention to migration |
| Film/Profile | PP profiles, sheets | Surface gloss, precipitation | Compound Lubricant Masterbatch | Select transparent grade for transparent parts |
| wear-resistant part | Gears, sliders, and silent parts | Long-lasting, wear-resistant, and smooth | Silicone Masterbatch | Use printed coating parts with caution |
Here’s a specific scenario: when making car door panels, subsequent painting and ultrasonic welding are required, so the lubricant has to be pushed down, prioritizing low-exudation types; otherwise, there will be paint pinholes and insufficient welding strength. For such parts, it’s better to make demolding a bit more troublesome than to let the lubricant exude and cause problems.
Dosage and matching points: Remembering four general formulas is enough
The addition and combination of lubricants follow certain rules, so you don't have to start from scratch every time. Four general formulas cover the mainstream practices.
PE wax combined with calcium stearate, loose inside and separated outside; that balance point is not calculated from reports, it is tested on the machine one mold at a time.
◆ General PP/PE Injection Molding: PE wax (internal, 0.3%-0.5%), calcium stearate (external, 0.1%-0.3%), total 0.5%-0.8%, balancing flowability and mold release.
◆ High filling/masterbatch: EBS or PE wax (0.5%-2%), lubricating and dispersing, helps pigments and fillers to disperse.
◆ Automotive welded and painted parts: low precipitation lubrication and reduction, with priority on welding strength and coating adhesion.
◆ Wear-resistant silent parts: silicone masterbatch (0.5%-2%), long-lasting smoothness and wear resistance, avoid printing and coating areas.
Finally, three reminders: First, adjust both internal and external lubricants simultaneously; adding only one side will cause imbalance—only internal lubrication causes poor release and only external lubricants for flow sticking; Second, for welding, coating, screen printing, and bonding parts, the total amount of lubricant should be strictly controlled, as precipitation will directly drag things down; Third, lubricants and dispersants should often be used in EBS/PE wax, so avoid repeated stacking and excessive use.
When making welded and coated parts, the total amount of lubricant should be pressed down; don't be greedy for that bit of slipperiness.
Lubrication: balance inside and out.
Processing and Compliance Red Lines: Avoid These Five Pitfalls
If the lubrication is not done properly, it either sticks to the mold or forms frost. The key steps and the consequences of mistakes are shown in the table below.
| link; segment; part | Reference value | The consequences of doing wrong |
|---|
| Proportion of inside to outside | Inner 0.3-0.5%, outer 0.1-0.3% | Imbalance → demolding difference or material flow viscosity |
| Total control | Total 0.5%-0.8%, adjusted separately for special cases | Excess → Frosting, welding coating decreases |
| Hybrid dispersion | Thoroughly premix with the resin | Uneven → local precipitation, surface patterning |
| transparent part | Choose transparent-grade lubricant | Wrong use → Decreased light transmittance, fogging |
| Welded coated parts | Lubricant reduction or low deposition | Precipitation → Shrinkage cavity, poor adhesion |
Compliance Red Lines: Lubricants for food contact must comply with GB 4806 or relevant FDA regulations; silicone masterbatches have requirements in some migration tests; check REACH when exporting to the EU. For welding, coating, and screen-printed parts, lubricant leaching is often a major source of customer complaints, so adhesion and leaching tests must be conducted at the small-scale trial stage.
FAQ: Six Common Questions from the Workshop and Purchasing
Q1: Can domestic lubricants replace imported materials?
Sure. For general lubricants like PE wax, calcium stearate, and EBS, the gap between domestic mainstream grades is already very small; you can test them on the machine for demolding and surface performance. In terms of long-lasting smoothness and migration control, imported silicone masterbatches still have some advantages. The correct approach is to take kilogram-level samples to the machine for comparison of demolding, surface, exudation, and welding coating adhesion, and after passing, gradually scale up to small batches. For machine-side comparison, the samples and reference materials can be prepared at kilogram-level by Cologne New Materials, with melting point and viscosity parameters attached.
Q2: The surface of the product has a whitish frost; is it because too much lubricant was added?
Most likely. Excess lubricant can migrate to the surface and form a white frost. First, reduce the total amount of lubricant, then check the internal and external ratio; if it is a transparent part, see if a stearic acid type with a large tendency to precipitate was chosen.
Q3: How exactly do internal lubrication and external lubrication differ?
Simply put: PE wax and EBS lean inward, penetrating the melt to reduce viscosity and promote flow; calcium/zinc stearate lean outward, migrating to the metal wall to prevent mold sticking and aid demolding. In practice, formulations often use both to find the balance point.
Q4: Why can't my part be welded, and why does the paint peel off?
First, suspect lubricants. Lubricating precipitation weakens weld surface and coating adhesion. Reduce the amount of lubricant or switch to a lower precipitation variety, then perform welding strength and hundred-grid adhesion tests.
Q5: Why can't silicone masterbatch be used casually?
Silicone has strong migration and a smooth feel, but it can cause printing, coating, and bonding to bloom or lose adhesion. Parts that require subsequent processing should avoid it; only purely wear-resistant and quiet parts are suitable.
Q6: Are lubricants and dispersants the same thing?
They are not the same thing, but EBS and PE wax often serve dual purposes — both lubricating and aiding dispersion. In the formulation, the quantities need to be calculated comprehensively, so don't stack the two to an excessive amount.
Three-Step Checklist for Material Selection: Follow It to Avoid Pitfalls
◆ Step 1: Observe the symptoms: First, distinguish whether it is “not flowing” or “not demolding” — for poor flow, add internal lubricant PE wax; for demolding issues, add external lubricant calcium stearate.
◆ Step 2: Determine total amount: Set the total usage at 0.5%-0.8% based on internal and external ratios; strictly reduce for welded, coated, or printed parts; use silicone masterbatch for wear-resistant parts.
◆ Step 3: Test on machine: In small-scale trials, be sure to check demolding, surface quality, blooming, and welding/coating adhesion. Once qualified, scale up and request batch reports for documentation.
No Sticking, No Blooming: Lubrication Balance Adjusted by Data
The core of lubricants is the balance between internal and external lubrication — internal lubrication reduces viscosity, external prevents sticking. Too much on either side causes problems. When Cologne New Materials supplies PE wax, EBS, calcium stearate, etc., they can provide key parameters such as melting point, viscosity, and acid value to help customers quickly determine the internal/external lubricant ratio; for sticking or blooming issues, gram-scale samples of different types can be sent for comparison and adjustment.
Last spring, a PP household appliance shell injection molding factory was troubled by sticking for a month — each mold required prying, with about 5% scrap rate, and the molds were scratched. Manager Wu from Cologne checked their formula: they added 0.8% PE wax but only 0.1% calcium stearate, clearly insufficient external lubrication. He suggested reducing PE wax to 0.4% and increasing calcium stearate to 0.3%, and sent corresponding samples. After the client adjusted following his guidance, sticking basically disappeared the same day, and the scrap rate dropped to about 0.5%. Shop floor staff said, finally no more daily battles with the copper scraper.
What is the ratio of your PE wax to calcium stearate?
Disclaimer: The brands, trademarks, and product names mentioned in this article belong to their respective 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 test reports from the respective manufacturers. This article does not constitute any purchasing or investment advice. Readers operate at their own risk.
