BOPP电容膜用什么料？先把一件事说清：电容膜级 PP 专用料的最高门槛不是性能指标，是"不加任何添加剂"。而改性PP造粒的本质是加助剂，加了灰分就压不下来，是工艺路线冲突，不是水平问题。
"BOPP电容膜用什么料？要那种灰分压到 ppm 级的。"
这是电容膜这条线最常被问到的一句话。后半句往往是："金属化用的，不能有滑剂、不能有抗粘、也不能有成核剂。"
先把最该先说清的一句摆出来：电容膜级 PP 专用料的最高门槛，不是什么性能指标，是"不含任何添加剂"。 灰分要压到几十 mg/kg 即 ppm 量级，铝硅钛钙这些金属离子各压到几 mg/kg 以内，滑爽剂、抗粘连剂、成核剂、抗静电剂一个都不能加。
而改性PP造粒这件事，本质上就是"加东西"。加了助剂，性能才好调、才好用；可加了助剂，灰分就上去了、可析出物就多了。所以这条赛道上，"我们做得不够好"这句话是错的——是工艺路线本身冲突，不是水平问题。把这句话讲在前面，比硬接一张单有用得多，这是本文最想说清的一点。
一、BOPP 电容膜的工况六维：介质损耗和击穿场强是产品定义项
结论先说：六个维度里，载荷和寿命不是按"承重 / 几年"算的，是按"电场强度 / 数千小时高温老化"算的；外观不是"做好了就行"，是无鱼眼、无杂质、金属化层不脱层。
| 维度 | 实际工况 | 对材料的要求 |
|---|
| 温度 | 制膜熔体约 (240±5)℃；下游金属化、蒸镀与电容器工作温度随应用升级，新能源汽车驱动系统已进入 125–150℃ 级 | 耐热氧老化、热收缩小、高温下介电稳定 |
| 载荷 | 电场应力为主：薄膜工作场强常 200–400 V/μm 量级，DC-Link 等场景要求更高 | 高体积电阻率、低介质损耗、高击穿场强 |
| 介质 | 金属化层（锌 / 铝）、浸渍油或树脂；长期强电场下服役 | 不析出、不污染介质、金属化附着力稳 |
| 寿命 | 长寿命服役：新能源场景按 15 年 / 数千小时高温老化评估 | 氧化诱导期长、可析出物极低、抗老化 |
| 外观 | 膜面洁净、无鱼眼、低雾度；金属化层附着牢、不脱层 | 颗粒外观零杂质、雾度 <6%、黄色指数 ≤1.0 |
| 合规 | 电容器厂认证（DC-Link / 耐高温 / 长寿命）、整机验证 | 由电容器厂与检测机构承担，不在料端 |
载荷这一维最容易被套错模板。 很多人拿结构件"强度"理解电容膜，其实它扛的是电场；真正卡死选材的是体积电阻率、介质损耗因数、击穿场强，以及把它们稳住的"纯净度"。
二、材料路线对比：聚合级均聚料、改性造粒、成品膜，三方各管一段
结论先说：电容膜这条链上，聚合级料、改性造粒、成品膜是三件事，分别由三方做；改性PP造粒线只能做极边缘的辅助段，主体不做。
先把边界说在前面：电容膜级 PP 专用料走的是石化厂大装置在聚合端直供的聚合级均聚物，不是改性造粒线的产品。 它要求等规指数 M 型 ≥98.0%、R 型 ≥96.0%，灰分 ≤30 mg/kg，金属元素各压到几 mg/kg 以内，且不加速滑剂、抗粘连剂、成核剂、抗静电剂任何一样——纯净度都在聚合端与纯化里定下来，下游补不上去。
| 路线 | 主体 | 落在谁手里 | 改性PP造粒能不能做 |
|---|
| ① 聚合级均聚 PP 专用料（电容膜级） | 本色颗粒，等规度高、灰分 ppm 级、无任何添加剂 | 石化厂大装置（聚合 + 纯化） | 不做。 纯净度在聚合端定，改性端补不上 |
| ② 改性PP造粒（加助剂） | 填充 / 增强 / 阻燃 / 爽滑等改性粒子 | 改性造粒线（本厂这一类） | 能做，但灰分与析出无法满足电容膜门槛 |
| ③ 成品电容膜（金属化膜 / 粗化膜） | BOPP 双向拉伸膜卷 | 膜厂（双向拉伸产线） | 不做。 双向拉伸与造粒是两套装备体系 |
三条路线没有"谁更好"，只是分工：① 决定膜能不能既纯净又拉得出来，② 解决"加了功能怎么好用"，③ 决定膜卷本身的电性能与表观。对电容膜，① 和 ③ 是主体，② 在主体上入场即冲突。
为什么冲突？看灰分从哪来。
| 灰分 / 金属来源 | 来自哪一步 | 对电容膜的影响 |
|---|
| 成核剂、抗氧剂、爽滑剂等助剂本身 | 改性造粒必加 | 直接抬升灰分、引入金属离子，击穿场强下降 |
| 填料（滑石粉、玻纤、硫酸钡等） | 增强 / 填充改性 | 灰分飙升，且分布不均 |
| 载体树脂与低分子物 | 母粒、相容剂 | 可析出物增多，介质损耗上升 |
| 设备磨损金属 | 造粒螺杆 / 模头 | 铝硅钛钙金属离子超标 |
文字版结论：灰分的来源，几乎每一项都对应"改性造粒为什么要加东西"；加了助剂耐用、好脱模、好调滑爽，可电容膜偏偏要"什么都不加"，是两条路线在起点就分叉了。
三、★ 电容膜级 PP 专用料选型判据表：灰分 ppm 级是第一判据
结论先说：这张表第一项就是电容膜的第一判据——灰分与金属离子；更该被重视的是第三列"怎么测"，不是"测哪个"。
据公开团体标准 T/CPCIF 0332-2024《塑料 电容器薄膜用聚丙烯（PP）专用料》（现行），专用料命名方式为 PP-H FC03R（R = 粗化膜）/ PP-H FC03M（M = 金属化膜），字符组 3 为 MFR 标称值。主要要求如下：
| 指标 | 门限值（典型） | 验证方法 · 标准号 | 常见失效 | 通行解法 |
|---|
| 灰分 | ≤30 mg/kg | GB/T 9345.1，铂金坩埚直接燃烧法 A 法，850±50℃ | 灰分超标、击穿场强下降 | 走聚合级无添加通道 |
| 金属元素（铝 / 硅 / 钛 / 钙） | ≤6 / ≤3 / ≤3 / ≤6 mg/kg | 灰化后元素分析 | 金属离子超标、介电损耗上升 | 聚合端纯化 |
| 等规指数 | M 型 ≥98.0%，R 型 ≥96.0% | GB/T 2412（仲裁） | 结晶不均、厚薄波动 | 石化厂牌号定 |
| 拉伸弹性模量 / 屈服应力 | ≥1300 MPa（1 mm/min）/ ≥34.0 MPa（50 mm/min） | GB/T 1040.2-2022，1A 型试样 | 膜强度不足、拉伸破膜 | 牌号定 |
| 薄膜雾度 / 黄色指数 / 挥发分 | <6% / ≤1.0 / ≤0.20% | GB/T 2410；黄色指数与挥发分按相应方法 | 外观降等、后期析出 | 聚合级纯化 |
| 熔融温度 | 167.0±3.0℃ | DSC 方法 | 加工窗口偏移 | 牌号定 |
| 氧化诱导时间 OIT（200℃） | ≥35 min | GB/T 19466.6，铝坩埚 | 热老化寿命不足 | 聚合级稳定体系 |
| 体积电阻率 | ≥3.0×10¹⁵ Ω·m | GB/T 31838.2-2019，1.0 mm±0.1 mm 试样，1 kV | 漏电、发热 | 无添加 |
| 介质损耗因数（工频 50 Hz） | ≤5.0×10⁻⁴ | GB/T 1409-2006，西林电桥法，场强 1 kV/mm | 介质发热、损耗大 | 无添加 |
| 颗粒外观（SH/T 1541.1） | 黑粒 0 个/kg、色粒和黑斑粒 ≤0 个/kg、大粒和小粒 ≤10 g/kg | SH/T 1541.1 | 晶点、黑点、膜面缺陷 | 聚合端洁净控制 |
文字版结论：灰分与金属离子是入场券中的入场券——它不过，后面所有电性能都不用谈。标准还给出一组流延膜制备的公开评价条件（仅用于按指定制膜条件评价专用料）：冷却辊 (26±2)℃、螺杆长径比不小于 25、口模狭缝 0.3~0.4 mm、熔体温度 (240±5)℃、牵引速度 (8.0±0.5) m/min、膜厚 (0.030±0.005) mm、不使用风刀及过滤网。注意：评价的是"专用料"，不是"成品膜"。
顺带把成品膜量级摆出来，方便理解"料端"和"膜端"的边界（据公开企业产品资料，B 级，可作量级参照）：
| 类型 | 厚度 | 关键性能量级 | 来源分级 |
|---|
| 金属化膜（MP） | 4–15 μm | 拉伸强度 纵向 155–165 MPa、横向 310–325 MPa；断裂伸长率 纵向 157–166%、横向 57–60%；介电强度（电极法）平均 522–605 V/μm；介质损耗因数 tgδ 2×10⁻⁴~2.8×10⁻⁴；体积电阻率约 1.7×10¹⁵~1.9×10¹⁵ Ω·m | B 级（企业产品资料） |
| 粗化膜（RP / RRP） | 6–15 μm | 表面粗糙度 0.34–0.45 μm；介电强度（电极法）平均 495–531 V/μm、（元件法）平均 387–436 V/μm；空隙率约 9.5% | B 级（企业产品资料） |
文字版结论：上表的承诺对象是"膜卷"，不是"粒子"；数值由膜厂在双向拉伸 + 金属化 / 粗化工艺里兑现，测试按 GB/T 12802 系列，改性造粒线不对其负责。
四、常见失效与根因：灰分上不去，多半是"加了什么"没想清
结论先说：电容膜选材最常见的错，不是"选错牌号"，是"把改性料思路套到聚合级料上"。
失效一：以为"加点助剂也能过电容膜门槛"。这是错的，也是这条线最典型的误判。
电容膜级要求无任何添加剂，而改性PP造粒每一个功能点——爽滑、抗粘、成核、抗氧、增强——都靠加东西实现。加一点点，灰分、金属离子、可析出物一并上升，电阻率与介质损耗随之劣化。这不是"加得巧不巧"，是加与不加本身对立。
失效二：以为"灰分低一点就行，差个几十 mg/kg 无所谓"。
对结构件或许如此，对电容膜不是。据公开行业资料（B 级），电工级 PP 树脂的评判口径是：灰分 ≤50 ppm（高端 ≤20 ppm）、金属离子 ≤3 ppm、不含任何添加剂；1 MHz 下介电损耗 ≤0.0005、介电常数稳定 2.2~2.3；薄膜常温击穿场强 ≥50 kV/mm；熔指 2.5~3.5、等规度 ≥98%；氧化诱导期长、可析出物极低。每一个"极低""极纯"都对应"不加东西"。
敢否定一个常见做法：有人拿着"我们改性PP能做薄膜"去对接电容膜需求。这话对普通包装膜成立（如爽滑、抗粘母粒那一类，见 PP-AE0），对电容膜不成立。把两件事并成一件说，最后一定是料送进去、灰分测出来、整批退回。先分清是"包装膜"还是"电容膜"，比先谈配方重要。
失效三：以为"料纯了，膜的性能自然就达标"。
也不对。聚合级纯料只是入场券，膜的电性能靠双向拉伸取向、金属化 / 粗化工艺与洁净环境共同兑现；料端只负责"纯净且可加工"，不负责"介电强度"这一列——那是膜厂的事。
五、验证顺序：从颗粒外观到介电强度，每一级不过就退回
结论先说：电容膜级专用料的验证顺序是"纯净度在前、电性能在后、制膜评价在最后"；顺序反了，失败会落在制膜那一步。
`
① 颗粒外观 黑粒 / 色粒 / 黑斑粒 / 大小粒（SH/T 1541.1）
↓ 有黑粒或杂质 → 退回聚合端洁净控制
② MFR 与等规指数 MFR 按牌号称值；等规指数 GB/T 2412（M≥98.0% / R≥96.0%）
↓ 不过 → 退回牌号与聚合工艺
③ 灰分与金属元素 灰分 GB/T 9345.1（≤30 mg/kg）；铝硅钛钙各按门限
↓ 超标 → 退回聚合级无添加通道（这一级是电容膜的命门）
④ 挥发分与黄色指数 挥发分 ≤0.20%；黄色指数 ≤1.0
↓ 不过 → 退回纯化与稳定体系
⑤ OIT 与熔融温度 OIT(200℃) ≥35 min（GB/T 19466.6）；熔融温度 167.0±3.0℃
↓ 不过 → 退回热稳定体系
⑥ 体积电阻率与介质损耗 体积电阻率 ≥3.0×10¹⁵ Ω·m（GB/T 31838.2-2019）
介质损耗因数 ≤5.0×10⁻⁴（GB/T 1409-2006）
↓ 不过 → 退回无添加与纯化
⑦ 流延膜雾度与鱼眼 按公开评价条件制流延膜，看雾度 <6% 与鱼眼
↓ 不过 → 退回聚合端与制膜条件
⑧ 制膜后拉伸与介电强度 双向拉伸后测拉伸与介电强度（按 GB/T 12802 系列）
↓ 不过 → 退回制膜工艺与专用料匹配
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最常被跳过的两处：跳过 ③ 直接做 ⑥，把"灰分超标"留到电性能测试才暴露；跳过 ⑦ 直接做 ⑧，一次双向拉伸打样就是整批成本，问题其实在更前面的料端已定。
六、反向诚实：这四类需求该找石化厂或膜厂，我们接不住
结论先说：这一节讲"什么时候别找我们"。把这句话说在前面，诚实边界才完整。
| 出现的情况 | 为什么落到别的通道 | 该找谁 |
|---|
| 要聚合级电容膜专用料（灰分 ppm 级、无任何添加剂） | 添加剂是改性造粒的必需品，加了灰分就压不下来——工艺路线冲突，不是水平问题 | 石化厂（聚合级均聚物通道） |
| 要 BOPP 双向拉伸制膜 | 分步或同步双向拉伸产线与造粒是两套装备体系 | 膜厂 |
| 要成品膜性能承诺（介电强度、tgδ、粗糙度、空隙率） | 承诺对象是膜卷 | 膜厂 |
| 要电容器端的认证（DC-Link、耐高温、长寿命） | 属电容器厂与整机验证 | 电容器厂 / 检测机构 |
规律一致：凡是"整张膜的纯净度基体"和"成膜工艺本身"这两类要求，都不该由改性PP造粒线去接。 我们不做这一块，也不冒充能接。把这条线讲清楚，客户反而更愿意把能接的那一小段交过来。
那我们能参与的只有极边缘的辅助方向：一是非电容级的通用 BOPP 包装膜用的功能助剂方向——但这一块与 PP-AE0（BOPP 薄膜爽滑与析出）是同一话题，本篇只做一句指路，不展开；二是薄膜加工所涉及的某些功能助剂方向（非电容级语境）。主体明确不接，也不冒充能接。
一条经验：这类询盘，先分清客户要的是"聚合级粒子""膜卷"还是"电容器认证"——要粒子的指石化厂，要膜卷的指膜厂，要认证的指电容器厂与检测机构。三步分完，剩下的才是我们能聊的。
七、换料风险清单：双向拉伸膜的口径，不是注塑模具口径
结论先说：电容膜线的换料风险和注塑线不是一回事——注塑看模具收缩率与浇口，双向拉伸看拉伸温度倍率与急冷辊。拿注塑清单去对必漏项。
| 要动的项 | 需要确认什么 | 不做会怎样 |
|---|
| 拉伸温度与倍率 | 纵拉 / 横拉温度窗口与拉伸倍率是否匹配新料 | 厚薄不均、破膜、取向不足 |
| 纵向 / 横向配比 | 纵拉与横拉倍率比、取向平衡 | 挺度异常、热收缩各向失衡 |
| 急冷辊 | 辊温与线速决定结晶状态与表面质量 | 雾度上升、结晶不均、金属化附着差 |
| 收卷张力 | 张力与卷径匹配 | 皱褶、暴筋、松卷、层间伤 |
| 金属化前表面处理 | 电晕 / 蒸镀前处理与表面张力 | 金属化层附着力不足、脱层 |
| 验证顺序 | 颗粒外观 → MFR 与等规 → 灰分与金属 → 挥发分与黄指 → OIT 与熔温 → 电阻率与损耗 → 流延雾度鱼眼 → 制膜拉伸介电 | 风险全部压到制膜打样那一步集中爆发 |
换料要动的是拉伸温度倍率、急冷辊、收卷张力、金属化前处理四块，其中最该先谈的还是验证顺序——跳过料端直接做双向拉伸打样，等于用整批成本去发现粒子本身就能测出的问题。
八、一页纸汇报表：电容膜选材可以直接贴进 PPT
结论先说：判断标准只有一条——客户拿这张表，能不能一次会议里把"找谁"定下来。
| 场景 | 推荐路线 | 关键指标 | 验证标准 | 需先确认的条件 |
|---|
| 要电容膜级 PP 粒子 | 石化厂聚合级均聚专用料（PP-H FC03R / FC03M） | 灰分 ≤30 mg/kg；金属离子；等规指数；OIT ≥35 min | T/CPCIF 0332-2024 | 膜型（粗化 R / 金属化 M）、MFR 档 |
| 要成品电容膜卷 | 膜厂 BOPP 双向拉伸（金属化 / 粗化） | 介电强度、tgδ、粗糙度、空隙率 | GB/T 12802 系列 | 金属化还是粗化、厚度档 |
| 要电容器认证 | 电容器厂 + 检测机构（DC-Link / 耐高温 / 长寿命） | 整机验证项目 | 电容器厂企标 / 整机规范 | 应用工况（如新能源 125–150℃） |
| 非电容级 BOPP 包装膜 | 改性造粒（功能母粒 / 助剂方向） | 爽滑、抗粘、析出控制 | 见 PP-AE0 | 用途与下游工艺 |
文字版结论：别把"纯净度、成膜、认证"三件事塞进"要一种好料"一句里——三件事各自找不同主体。最有用的是最后一列，它决定报出去的话能不能兑现。
九、这个方向上最容易出问题的，往往不是料——是路线选错
行业通行的做法是把三件事分清楚：聚合级纯料找石化厂、成品膜找膜厂、电容器认证找电容器厂与检测机构。难点不在"谁的料更好"，在"边界画在哪儿"。
宁波市科隆新材料有限公司在电容膜这条线上主体不接——不生产聚合级电容膜专用料，不做双向拉伸制膜，也不对成品膜的电性能与电容器认证负责。能参与的只有极边缘的辅助段：非电容级语境下薄膜加工涉及的某些功能助剂方向；通用 BOPP 包装膜那一块的功能母粒与析出控制，请看 PP-AE0 那一篇，本篇不再展开。
常见问答
问：你们能做电容膜用的 PP 料吗？
答：不能。电容膜级要求灰分压到 ppm 级且无任何添加剂，而改性PP造粒的本质是加助剂——加了灰分就压不下来，是工艺路线冲突，不是水平问题。聚合级料请直接找石化厂。
问：那为什么有些资料说改性 PP 也能做薄膜？
答：那是普通包装膜（BOPP 包装膜）方向，靠爽滑 / 抗粘母粒这类功能助剂实现，与电容膜的"无添加"门槛不是一回事；本方向与 PP-AE0 已划清界限，不混为一谈。
问：我们要做金属化膜电容，该找谁？
答：料找石化厂的聚合级专用料，膜找膜厂做双向拉伸与金属化，认证找电容器厂与检测机构按整机工况验证。这三步分清楚，比先谈配方有用。
想提醒一句：电容膜询盘最常见的错法，是先问"你们能不能做"，再问"加什么助剂能达标"。顺序反了——先定路线，再谈材料；这一步没定，后面全是返工。
十、最后说三句
第一，电容膜级 PP 专用料的最高门槛不是性能，是"不加任何添加剂"。 灰分 ppm 级、金属离子各 ≤3~6 mg/kg、不加速滑剂 / 抗粘剂 / 成核剂 / 抗静电剂——这几条在聚合端定，下游补不上。
第二，改性PP造粒的本质是"加东西"，和电容膜的"不加东西"在起点就冲突。 这不是我们做得不够好，是工艺路线本身对不上。
第三，把"纯净度、成膜、认证"分给三个主体，比先谈配方有用——料找石化厂、膜找膜厂、认证找电容器厂，边界画清，能接的那一小段才接得稳。
关于我们
选型卡住，通常卡在很具体的一步。
是不知道该走聚合级纯料还是改性路线，是灰分到底要压到哪个量级，是成品膜的性能该由谁承诺——说清卡在哪一步，比说"要一种好料"有用得多。
宁波市科隆新材料有限公司，自产改性聚丙烯（PP）造粒，覆盖均聚 / 无规共聚 / 抗冲共聚三档基材，以及填充、玻纤增强、增韧、阻燃、低气味低 VOC、耐候、免喷涂耐划伤等改性方向；兼营各大石化厂 PP 树脂、副牌料与大包料。
What material is used for BOPP capacitor film? Let's clarify one thing first: the highest threshold for PP specialized material for capacitor film is not performance indicators, but 'not adding any additives.' The essence of modified PP granulation is adding auxiliaries. If you add ash content, it cannot be reduced, which is a conflict in the process route, not an issue of skill level.
What material is used for BOPP capacitor film? It needs to have an ash content reduced to the ppm level.
This is the most frequently asked question about this capacitor film line. The latter part is often: 'It is used for metallization, so it cannot have any lubricant, anti-blocking agent, or nucleating agent.'
Let's start with the most important point that needs to be clarified first: the highest standard for capacitor film-grade PP special material is not any performance index, but that it "contains no additives". The ash content must be reduced to tens of mg/kg, which is at the ppm level, and metal ions like aluminum, silicon, titanium, and calcium must each be kept below a few mg/kg. No slip agents, anti-blocking agents, nucleating agents, or antistatic agents can be added.
The modification and granulation of PP is essentially about 'adding things.' By adding additives, the performance becomes easier to adjust and use; but adding additives also increases ash content and the amount of extractables. Therefore, in this field, the statement 'we are not doing well enough' is wrong—it’s a conflict in the process route itself, not a matter of skill. Emphasizing this point upfront is much more useful than just taking an order, and this is the main point this article wants to clarify.
1. The six operating conditions of BOPP capacitor film: dielectric loss and breakdown field strength are product definition parameters
Conclusion first: In the six dimensions, load and lifespan are not measured by 'bearing capacity / years,' but by 'electric field strength / thousands of hours of high-temperature aging'; appearance is not just 'good enough,' it must have no fish eyes, no impurities, and the metallized layer must not delaminate.
| Dimension | Actual operating conditions | Requirements for the materials |
|---|
| Temperature | The film-forming melt is approximately (240±5)℃; with the downstream metallization, vapor deposition, and capacitor operating temperatures increasing with application upgrades, the drive systems of new energy vehicles have already reached the 125–150℃ level. | Heat-resistant oxidation aging, small thermal shrinkage, dielectric stability at high temperatures |
| Load | Primarily electric field stress: the working field strength of the film is often in the range of 200–400 V/μm, with higher requirements in scenarios such as DC-Link. | High volume resistivity, low dielectric loss, high breakdown field strength |
| Medium | Metalized layer (zinc/aluminum), impregnated oil or resin; operating under long-term strong electric field | No precipitation, does not contaminate the medium, stable metal adhesion |
| Lifespan | Long service life: New energy scenarios evaluated for 15 years / thousands of hours of high-temperature aging | Long oxidation induction period, extremely low precipitates, anti-aging |
| Appearance | The film surface is clean, free of fish eyes, and has low haze; the metallized layer adheres firmly and does not peel. | Granule appearance: no impurities, haze <6%, yellow index ≤1.0 |
| Compliance | Capacitor factory certification (DC-Link / high temperature resistant / long life), complete machine verification | Handled by the capacitor factory and inspection agency, not at the material end |
The load dimension is the easiest to be mistakenly applied with the wrong template. Many people interpret the 'strength' of structural components as an understanding of the capacitor film, but in fact, it withstands the electric field; what really dictates material selection are the volume resistivity, dielectric loss factor, breakdown field strength, and the 'purity' that stabilizes them.
2. Comparison of material routes: polymer-grade homopolymer, modified granules, finished film, each party manages one section
Conclusion first: On the capacitor film chain, polymer-grade material, modified granulation, and finished film are three separate things, handled by three different parties; a modified PP granulation line can only handle the extreme peripheral auxiliary sections, not the main part.
Let's put the boundaries upfront: The capacitive film-grade PP special material is a polymer-grade homopolymer directly supplied from the polymerization end of large petrochemical plants, not a product from modified pelletizing lines. It requires a meso index M type ≥98.0%, R type ≥96.0%, ash content ≤30 mg/kg, metal elements each limited to a few mg/kg, and no accelerators, anti-blocking agents, nucleating agents, or antistatic agents are added—its purity is determined at the polymerization and purification stages and cannot be supplemented downstream.
| Route | Subject | Whose hands will it fall into | Can modified PP be granulated? |
|---|
| ① Homopolymer PP for polymer-grade (capacitor film grade) | Natural color granules, high uniformity, ash content at ppm level, no additives | Large Petrochemical Plant Units (Polymerization and Purification) | Don't do it. Purity is determined at the polymerization end; it cannot be supplemented at the modification end. |
| ② Modified PP granulation (with additives) | Filling / Enhancing / Flame-retardant / Smooth and other modified particles | Modified granulation line (this type in our factory) | It can be done, but the ash content and precipitation cannot meet the capacitor film threshold. |
| ③ Finished capacitor film (metalized film / roughened film) | BOPP Bi-axially Oriented Polypropylene Film Roll | Film Factory (Biaxial Stretching Production Line) | No. Biaxial stretching and granulation are two separate sets of equipment systems. |
None of the three routes is 'better'; they are just different divisions of labor: ① Determine whether the film can be both pure and stretchable, ② Solve the problem of 'how to make added functions practical,' ③ Decide the electrical performance and appearance of the film roll itself. For capacitor films, ① and ③ are the main focus, while ② conflicts as soon as it enters the main focus.
Why the conflict? See where the ash comes from.
| Ash / Metal Source | From which step | The effect on the capacitor membrane |
|---|
| Nucleating agents, antioxidants, lubricants, and other additives themselves | Modified granulation must be added | Directly increasing the ash content and introducing metal ions cause a decrease in breakdown field strength |
| Fillers (talc, glass fiber, barium sulfate, etc.) | Reinforced / Filled Modification | Ash content is soaring and unevenly distributed |
| Carrier resins and low molecular weight materials | Masterbatch, compatibilizer | Precipitable matter increases, and dielectric loss rises |
| Equipment wear metal | Granulation screw / die head | Excessive levels of aluminum, silicon, titanium, and calcium metal ions |
Text version of the conclusion: The source of ash corresponds almost exactly to 'why additives are added in modified granulation'; adding additives makes it durable, easy to demold, and smooth to adjust, yet capacitor films insist on 'adding nothing at all'. The two routes diverge right from the starting point.
3. ★ Selection Criteria Table for Capacitor Film Grade PP: Ash content at ppm level is the primary criterion
Conclusion first: The first item on this table is the primary criterion for capacitor films—ash content and metal ions; what deserves more attention is the third column 'how to measure,' not 'what to measure.'
According to the public group standard T/CPCIF 0332-2024 "Plastics - Special polypropylene (PP) materials for capacitor films" (current version), the naming method for special materials is PP-H FC03R (R = roughened film) / PP-H FC03M (M = metallized film), with character group 3 representing the nominal MFR value. The main requirements are as follows:
| Indicator | Threshold Value (Typical) | Verification Method · Standard Number | Common Failures | Common solution |
|---|
| Ash content | ≤30 mg/kg | GB/T 9345.1, Platinum Crucible Direct Combustion Method A, 850±50℃ | Excessive ash content, breakdown field strength decrease | Go through aggregation-level additive-free channels |
| Metal elements (Aluminum / Silicon / Titanium / Calcium) | ≤6 / ≤3 / ≤3 / ≤6 mg/kg | Elemental analysis after ashing | Excessive metal ions, increase in dielectric loss | Aggregate End Purification |
| Waiting Standard Index | M type ≥98.0%, R type ≥96.0% | GB/T 2412 (Arbitration) | Uneven crystallization, thickness fluctuation | Petrochemical plant grade designation |
| Tensile Elastic Modulus / Yield Stress | ≥1300 MPa (1 mm/min) / ≥34.0 MPa (50 mm/min) | GB/T 1040.2-2022, Type 1A specimen | Insufficient film strength, tearing under tension | Grade designated |
| Film Haze / Yellowness Index / Volatile Content | <6% / ≤1.0 / ≤0.20% | GB/T 2410; Yellow index and volatile matter according to the corresponding methods | Appearance downgrade, later precipitation | Aggregate-level purification |
| Melting temperature | 167.0±3.0℃ | DSC method | Processing Window Offset | Grade designated |
| Oxidation Induction Time OIT (200℃) | ≥35 min | GB/T 19466.6, aluminum crucible | Insufficient thermal aging life | Polymer-grade stable system |
| Volume resistivity | ≥3.0×10¹⁵ Ω·m | GB/T 31838.2-2019, 1.0 mm ± 0.1 mm specimen, 1 kV | Electric leakage, overheating | No additives |
| Dielectric loss factor (Power frequency 50 Hz) | ≤5.0×10⁻⁴ | GB/T 1409-2006, Xilin Bridge Method, Field Strength 1 kV/mm | Medium heating, high loss | No additives |
| Granule Appearance (SH/T 1541.1) | Black granules 0 pcs/kg, colored granules and black spots ≤0 pcs/kg, large granules and small granules ≤10 g/kg | SH/T 1541.1 | Crystal spots, black spots, film surface defects | Aggregation End Cleanliness Control |
Text Version Conclusion: Ash content and metal ions are the tickets to entry — without them, all subsequent electrical properties are irrelevant. The standard also provides a set of publicly disclosed evaluation conditions for cast film preparation (only for evaluating special materials under the specified film-forming conditions): cooling roll (26±2)℃, screw length-to-diameter ratio not less than 25, die slit 0.3~0.4 mm, melt temperature (240±5)℃, traction speed (8.0±0.5) m/min, film thickness (0.030±0.005) mm, without using air knives or filter screens. Note: The evaluation is for 'special material,' not 'finished film.'
By the way, lay out the scale of the finished film to facilitate understanding of the boundaries between the 'material side' and the 'film side' (according to publicly available company product information, grade B, can be used as a reference for scale):
| Type | Thickness | Key performance level | Source Classification |
|---|
| Metalized Film (MP) | 4–15 μm | Tensile strength: longitudinal 155–165 MPa, transverse 310–325 MPa; elongation at break: longitudinal 157–166%, transverse 57–60%; dielectric strength (electrode method) average 522–605 V/μm; dielectric loss factor tgδ 2×10⁻⁴~2.8×10⁻⁴; volume resistivity approximately 1.7×10¹⁵~1.9×10¹⁵ Ω·m | Class B (Enterprise Product Information) |
| Roughened Membrane (RP / RRP) | 6–15 μm | Surface roughness 0.34–0.45 μm; dielectric strength (electrode method) average 495–531 V/μm, (component method) average 387–436 V/μm; porosity approximately 9.5% | Class B (Enterprise Product Information) |
Text Version Conclusion: The commitment target in the above table is 'film roll,' not 'particle'; the values are fulfilled by the film factory in the biaxial stretching metallization/coarsening process, tested according to the GB/T 12802 series, and the modified granulation line is not responsible for it.
4. Common Failures and Root Causes: If the ash content doesn’t increase, it is mostly because 'what was added' wasn’t clearly thought through.
Conclusion first: The most common mistake in selecting capacitor films is not 'choosing the wrong grade,' but 'applying the modified material approach to polymer-grade materials.'
Failure 1: Thinking that 'adding the highlighted additive can also pass the capacitor membrane threshold.' This is wrong and is the most typical misjudgment in this line.
The requirements for capacitor film are that no additives are allowed, whereas each functional aspect of modified PP granules—smoothness, anti-stick, nucleation, anti-oxidation, reinforcement—is achieved by adding something. Adding even a little increases ash content, metal ions, and extractables, causing resistivity and dielectric loss to deteriorate. This is not a matter of 'adding cleverly or not'; adding and not adding are inherently opposed.
Failure 2: Thinking 'It's fine as long as the ash content is a bit lower; a difference of a few dozen mg/kg doesn't matter.'
Maybe this is true for structural components, but not for capacitor films. According to publicly available industry data (Grade B), the evaluation criteria for electrical-grade PP resin are: ash content ≤50 ppm (≤20 ppm for high-end), metal ions ≤3 ppm, containing no additives; dielectric loss ≤0.0005 at 1 MHz, dielectric constant stable at 2.2~2.3; film room temperature breakdown strength ≥50 kV/mm; melt flow index 2.5~3.5, isotacticity ≥98%; long oxidation induction period, extremely low extractables. Every 'extremely low' and 'extremely pure' corresponds to 'nothing added'.
Can we deny a common practice: some people present 'our modified PP can make films' to match the demand for capacitor films. This statement is valid for ordinary packaging films (such as smooth, anti-stick masterbatches, see PP-AE0), but it does not hold for capacitor films. Combining the two things as one will ultimately lead to the material being sent in, ash content tested, and the whole batch rejected. It's more important to first distinguish whether it's 'packaging film' or 'capacitor film' than to discuss the formulation.
Failure Three: Thinking 'If the material is pure, the membrane's performance will naturally meet the standard.'
That's not right either. Aggregated-grade virgin material is just the entry ticket; the electrical performance of the film depends on biaxial stretching orientation, metallization/roughening processes, and a clean environment together to realize it; the material side only ensures 'purity and processability,' not 'dielectric strength'—that’s the responsibility of the film manufacturer.
5. Verification sequence: from particle appearance to dielectric strength, each level is just returned if not passed
Conclusion first: The verification sequence for capacitor film-specific materials is 'purity first, electrical performance second, film formation evaluation last'; if the sequence is reversed, failure will occur at the film formation step.
`
① Granule Appearance Black granules / Colored granules / Black spotted granules / Large and small granules (SH/T 1541.1)
↓ If there are black particles or impurities → Return to the polymerization end for cleanliness control
② MFR and isotactic index MFR is according to the rated value; isotactic index GB/T 2412 (M≥98.0% / R≥96.0%)
↓ However → Return to grade and polymerization process
③ Ash and Metal Elements Ash GB/T 9345.1 (≤30 mg/kg); Aluminum, Silicon, Titanium, and Calcium each according to the threshold
↓ Exceeds standard → Return to the additive-free polymer-grade channel (this level is the key point of the capacitor film)
④ Volatile Matter and Yellowness Index Volatile Matter ≤0.20%; Yellowness Index ≤1.0
↓ However → Return to purification and stabilization system
⑤ OIT and melting temperature OIT (200℃) ≥35 min (GB/T 19466.6); melting temperature 167.0±3.0℃
↓ However → Revert to the thermally stable system
⑥ Volume Resistivity and Dielectric Loss Volume resistivity ≥ 3.0×10¹⁵ Ω·m (GB/T 31838.2-2019)
Dielectric loss factor ≤5.0×10⁻⁴ (GB/T 1409-2006)
↓ However → Revert to additive-free and purified
⑦ Cast Film Haze and Fish Eyes Produce cast film under publicly disclosed evaluation conditions, and check for haze <6% and fish eyes
↓ However → Return to the aggregation end and membrane-forming conditions
⑧ Stretching and Dielectric Strength After Film Formation: Measure the stretching and dielectric strength after biaxial stretching (according to GB/T 12802 series)
↓ However → Return to matching the film-forming process with specialized materials
`
The two most commonly skipped parts: skipping ③ and going straight to ⑥, leaving the 'excess ash' to be revealed only during the electrical performance test; skipping ⑦ and going straight to ⑧, a single bidirectional stretching sample is the cost for the entire batch, but the problem was actually determined earlier at the material stage.
6. Reverse honesty: For these four types of demand, you should go to the petrochemical plants or membrane factories, we can't handle them.
Conclusion first: This section talks about 'when not to look for us.' Saying this sentence upfront completes the boundary of honesty.
| The situation that occurred | Why did it fall to another channel | Who should I find? |
|---|
| Special material for aggregate-grade capacitor films (ash content at ppm level, without any additives) | Additives are essential for modified granulation. Once ash is added, it can't be compressed — this is a process route conflict, not an issue of skill. | Petrochemical Plant (Polymer-Grade Homopolymer Channel) |
| Need BOPP biaxially oriented film manufacturing | Stepwise or synchronous bidirectional stretching production line and granulation are two separate equipment systems | Film factory |
| Performance commitments for the finished film (dielectric strength, tgδ, roughness, porosity) | The promised object is the membrane roll | Film factory |
| Certification at the capacitor end (DC-Link, high temperature resistance, long lifespan) | Belongs to the capacitor factory and complete machine verification | Capacitor Factory / Testing Organization |
Consistent rules: Any requirements concerning the 'purity matrix of the entire film' and 'the film-forming process itself' should not be handled by the modified PP granulation line. We do not do this part, nor do we pretend we can handle it. By clarifying this line, customers are actually more willing to hand over the small portion that can be handled.
The only areas we can participate in are at the very marginal supporting directions: first, the direction of functional additives for general BOPP packaging films that are not at the capacitive level—but this topic is the same as PP-AE0 (slip and blooming of BOPP films), which will only be briefly mentioned here without further discussion; second, certain functional additive directions involved in film processing (in a non-capacitive context). We clearly will not take on the main part, nor pretend that we can.
One piece of experience: For such inquiries, first distinguish whether the customer wants 'aggregated-level particles,' 'film rolls,' or 'capacitor certification'—those asking for particles refer to petrochemical plants, those asking for film rolls refer to film factories, and those asking for certification refer to capacitor manufacturers and testing agencies. After completing these three steps, what remains is what we can actually discuss.
7. Material Change Risk List: The caliber of the biaxially stretched film is not the caliber of the injection mold.
Conclusion first: The risk of material change for capacitor film lines is not the same as for injection molding lines— for injection molding, it's about mold shrinkage rate and gate, while for biaxial stretching, it's about stretching temperature factor and quenching rollers. Using the injection molding checklist will inevitably miss items.
| Items to move | What needs to be confirmed | What will happen if I don't do it? |
|---|
| Stretching Temperature and Ratio | Whether the vertical/horizontal stretching temperature window matches the draw ratio of the new material | Uneven thickness, film breakage, insufficient orientation |
| Vertical / Horizontal Ratio | Longitudinal and transverse draw ratio ratio, orientation balance | Stiffness abnormality, anisotropic thermal shrinkage |
| Quenching Roller | Roll temperature and line speed determine the crystallization state and surface quality | Increase in haze, uneven crystallization, poor metallization adhesion |
| Rewinding tension | Tension and roll diameter matching | Wrinkles, broken veins, loose curls, interlaminar damage |
| Surface treatment before metallization | Corona / Pre-deposition Treatment and Surface Tension | Insufficient adhesion of the metallized layer, delamination |
| Verification order | Particle appearance → MFR and isotacticity → Ash content and metals → Volatile content and yellowness index → OIT and melting temperature → Resistivity and loss → Cast film haze and fish eyes → Film formation, stretching, and dielectric | All the risks are concentrated to explode at the film-making sample step |
Changing materials involves adjusting four areas: stretch temperature multiplier, quenching roller, winding tension, and pre-treatment before metallization. Among them, the one that should be discussed first is still the verification sequence—skipping the material end and directly doing bidirectional stretching sampling is equivalent to using the cost of the entire batch to discover problems that could have been detected in the particles themselves.
8. One-page report form: The selection of capacitor film material can be directly pasted into the PPT
Conclusion first: There is only one criterion—whether the client can use this form to determine 'who to contact' in a single meeting.
| Scene | Recommended Route | Key indicators | Verification Standard | Conditions that need to be confirmed first |
|---|
| PP particles for capacitor film grade | Petrochemical plant polymer-grade homopolymer special material (PP-H FC03R / FC03M) | Ash ≤30 mg/kg; Metal ions; Isotactic index; OIT ≥35 min | T/CPCIF 0332-2024 | Film type (roughened R / metallized M), MFR grade |
| Want finished capacitor film rolls | Film Factory BOPP Biaxially Oriented (Metallized / Textured) | Dielectric strength, tgδ, roughness, porosity | GB/T 12802 Series | Metallization or coarsening, thickness grade |
| Capacitor certification required | Capacitor Factory Testing Organization (DC-Link / High Temperature Resistant / Long Life) | Whole Machine Validation Project | Capacitor Factory Standards / Complete Machine Specifications | Application conditions (such as new energy 125–150℃) |
| Non-capacitor grade BOPP packaging film | Modified Granulation (Functional Masterbatch / Additive Direction) | Smooth, non-stick, precipitation control | See PP-AE0 | Applications and Downstream Processes |
Text version conclusion: Don't cram the three things 'purity, film formation, certification' into the phrase 'want a good material'—each of the three things should have a different subject. The most useful is the last column, as it determines whether what is reported can be fulfilled.
9. In this direction, the thing that most easily goes wrong is often not the materials, but choosing the wrong path.
The common practice in the industry is to distinguish three things: sourcing aggregate-grade pure materials from petrochemical plants, sourcing finished films from film manufacturers, and seeking capacitor certification from capacitor manufacturers and testing institutions. The difficulty is not 'whose material is better,' but 'where to draw the boundaries.'
Ningbo Cologne New Materials Co., Ltd. does not participate in the main line of capacitor films—it does not produce polymer-grade materials for capacitor films, does not perform biaxial stretching of film, and is not responsible for the electrical properties of finished films or capacitor certification. The only areas it can be involved in are at the very peripheral auxiliary stages: certain functional additives related to film processing outside the capacitor-grade context; and functional masterbatches and crystallization control for general BOPP packaging films. Please refer to the PP-AE0 article for details, which will not be expanded on in this article.
Frequently Asked Questions
Question: Can you produce PP material for capacitor films?
Answer: No. Capacitor-grade film requires ash content to be reduced to the ppm level with no additives, while the essence of modified PP granules is adding additives—once ash is added, it cannot be reduced; this is a conflict in the process route, not a matter of skill level. For polymer-grade material, please contact a petrochemical plant directly.
Question: Then why do some materials say that modified PP can also be used to make films?
Answer: That is the direction of ordinary packaging film (BOPP packaging film), relying on functional additives such as slip/anti-block masterbatch to achieve it, which is not the same as the 'additive-free' threshold of capacitor film; this direction has clearly been separated from PP-AE0 and should not be confused.
Question: If we want to make metallized film capacitors, who should we contact?
Answer: For the material, look for polymer-grade specialized material from petrochemical plants; for the film, have a film factory make biaxially oriented and metallized film; for certification, work with capacitor manufacturers and testing institutions to verify according to the complete device's operating conditions. Clarifying these three steps is more useful than discussing the formula first.
I'd like to give a reminder: The most common mistake in capacitor film inquiries is first asking 'Can you make it?' and then asking 'What additives are needed to meet the standards?' The sequence is reversed — you should first set the process route, then discuss the materials; if this step is not determined, everything that follows is rework.
Ten, Lastly, Say Three Sentences
First, the highest threshold for PP materials dedicated to capacitor film is not performance, but "no additives at all." Ash content at ppm level, metal ions each ≤3~6 mg/kg, no accelerated slip agents / anti-blocking agents / nucleating agents / antistatic agents — these are determined at the polymerization stage and cannot be compensated downstream.
Second, the essence of modified PP granulation is 'adding things', which conflicts with the 'not adding things' approach of capacitor films right from the start. This is not because we didn't do a good job, but because the process routes themselves are incompatible.
Third, assigning 'purity, film formation, and certification' to three separate entities is more useful than discussing the formula first—materials go to the petrochemical plant, the film goes to the film factory, and certification goes to the capacitor factory; by clearly defining the boundaries, only the part that can be connected can be connected stably.
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The selection process gets stuck, usually at a very specific step.
It's unclear whether to go with polymer-grade pure materials or a modified route, what level the ash content should be reduced to, and who should be responsible for guaranteeing the performance of the finished film—clarifying which step is stuck is much more useful than saying 'we need a good material'.
Ningbo Cologne New Materials Co., Ltd. produces modified polypropylene (PP) granules, covering homopolymer, random copolymer, and block copolymer base materials, as well as modifications including filled, glass fiber reinforced, toughened, flame-retardant, low odor and low VOC, weather-resistant, and scratch-resistant without coating; it also deals in PP resins from major petrochemical plants, off-spec materials, and bulk materials.
