可降解包装复合层用什么PP？先把一事说清：可降解包装的主体树脂是 PLA、PBAT、PBS、PHA、热塑性淀粉，不是 PP。本篇先分清可降解、可回收、生物基三个概念，再讲 PP 在相容剂与单一材质可回收两条线上的真实位置，并写明哪类单子该找降解料厂。
- 对照差异：本篇主线"三个概念区分 + PP 真实两个位置"，与 AE0/AE1/AE2/A48 各走一条线，不重叠
"给我一种可降解的 PP。"
这句话几乎每周都能听到。前半句要的是"埋土里能烂"，后半句要的是 PP 的挺度、耐热和便宜——这两件事，落到同一张膜上，是互相打架的。
先把本篇最大的干货点写在最前面：可降解包装的主体树脂是 PLA、PBAT、PBS、PHA、热塑性淀粉（TPS），不是 PP。PP 的分子主链是 C—C 单键，没有水解敏感位点，不具备生物降解能力——它只能做光氧老化裂解（碎成微塑料），那不是"可降解"，是"裂解"。 把裂解当降解，是整个行业最常见的误读，也是这篇要先掰开讲的事。
所以这篇不硬吹 PP 能进可降解包装——可降解包装用什么PP？答案不在 PP 主树脂上，而在相容剂与单材可回收两条线。它在这条赛道上真正站得住的，只有两个位置——相容剂方向、单一材质可回收（Mono-PP）方向。先把三个被混用的概念分清，再说这两处。
一、可降解包装的工况六维：介质和寿命两维决定"它到底要降解还是回收"
结论先说：六维里最该先定的是"介质"和"寿命"——介质决定能不能接触降解环境，寿命决定它是走"用完即弃后降解"还是"长期复用后回收"。这一维没定，后面全白谈。
| 维度 | 可降解包装的实际工况 | 对材料的要求 |
|---|
| 温度 | 堆肥条件典型 58℃ 级；家庭堆肥常温波动；热灌装/蒸煮件走 100℃+；冷链 −18℃ | 降解树脂耐热普遍不如 PP；PP 系耐热可作热封与结构层 |
| 载荷 | 购物袋、快递袋承重从几公斤到十几公斤；复合膜靠层结构与热封承担 | 拉伸与封口强度，按袋型定门限 |
| 介质 | 堆肥（高湿、微生物）、土壤、海水；内容物油脂、酸碱、含水 | 能否进入降解环境，是分水岭 |
| 寿命 | 一次性降解件按"丢弃后数周~数月降解"设计；复用件按"用几年后回收"设计 | 降解件要快崩解，回收件要慢老化 |
| 外观 | 透明度、挺括感、印刷适性 | PLA 透明度高、近 PET；PBAT 手感近 PE |
| 合规 | 走降解认证（GB/T 19277.1-2025 受控堆肥、GB/T 38082-2019 购物袋、EN 13432、ASTM D6400）或回收标识（聚烯烃回收流） | 认证是入场券，不是加分项 |
表注：温度、载荷、外观的量级来自公开行业资料（B 级），用于说明量级；具体门限须写进验收条件，并按对应标准实测。降解认证标准名称、年份与适用范围已逐一核实（见文末备忘）。
这两个系列最容易混的是"介质能降解"和"寿命够长"。一张 PLA/PBAT 袋的使命是"用完进堆肥"，它不需要挺过三年；一件 PP 周转箱的使命是"用三年进回收流"，它不需要埋土里烂掉。一个是设计成会消失，一个是设计成别消失——这两条线从根上就反着走。
二、先把三个被混用的概念掰开：可降解、可回收、生物基不是一回事
结论先说：这三个词被当成同义词用，是本篇首先要纠的错。它们管的是三件不同的事——"会不会被微生物吃掉""能不能回炉再造""原料来自动植物还是石油"。PP 只沾后两件里的一角，第一件不沾。
| 概念 | 说的是什么 | 典型材料 | PP 站不站得进去 |
|---|
| 可降解（生物降解） | 在堆肥 / 土壤 / 海水等条件下，被微生物代谢矿化，最终变 CO₂、水、生物质 | PLA、PBAT、PBS、PHA、热塑性淀粉（TPS） | 不站。PP 主链 C—C 单键无水解位点，不具备生物降解能力 |
| 可回收（循环） | 用后分拣、清洗、再熔融造粒，回到聚烯烃流 | PP、PE 及单材多层结构（Mono-PP） | 站得住。PP 耐热优于 PE，适配热灌装；单材结构解决分拣 |
| 生物基（原料来源） | 单体来自可再生生物质，不等于"能降解" | 生物基 PE、生物基 PP、PLA（部分生物基） | 部分沾边。生物基 PP 仍是非降解聚烯烃，走回收通道，不是降解通道 |
文字版结论："生物基"说的是出身，"可降解"说的是结局，"可回收"说的是去路——三件事正交。 一张"生物基 PP"袋，出身是植物，结局是不降解，去路是回收。把"生物基"读成"可降解"，是第二个常见误读。
这一节是本篇跟同系列 AE0/AE1/AE2/A48 都不重叠的地方：那四篇分别讲膜、热封、气柱、农膜的工况与改性，本篇只盯"概念区分 + PP 真实两位置"，不抢任何一条工艺线。
三、可降解树脂体系参数对比：PLA/PBAT 才是主角，PP 不在主树脂里
结论先说：三类降解树脂（PLA、PBAT、PBS/PHA）加 TPS 构成可降解包装的主体；PP 不在主树脂名单里，只在"界面"和"单材结构"里出现。下面这张表是给客户做量级判据用的，全部标 B 级。
| 树脂 | 来源 / 类型 | 关键性能量级（B 级） | 在包装里的位置 |
|---|
| PLA | 生物基热塑聚酯 | 透明度高、挺括、光泽近 PET；脆性大、断裂伸长率低、热变形温度约 55℃ | 主树脂之一，常需增韧与耐热改性 |
| PBAT | 石油基脂肪族—芳香族共聚酯 | 断裂伸长率 >600%，耐撕裂、手感近 PE 袋 | 主树脂之一，给韧性 |
| PBS / PBSA | 脂肪族聚酯 | 耐热略优于 PLA | 耐热降解件、餐具类 |
| PHA / PHBV | 微生物合成聚酯 | 海水亦可降解，成本高 | 特殊降解场景 |
| TPS（热塑性淀粉） | 淀粉 + 甘油塑化 | 降本、提速，常加 10%~30% | 填充降成本 |
| PP | 聚烯烃 | 挺度、耐热、低成本；非降解 | 不在主树脂；只在相容剂与单材可回收结构 |
据公开技术资料（B 级），主流配方里 PLA 与 PBAT 按质量比 3:7 至 5:5 共混，加相容剂协助分散，复合材拉伸强度可达 20~30 MPa（接近低密度聚乙烯袋水平）；为降本与提速常再加 10%~30% TPS 或少量碳酸钙。降解机理是水解断链 → 微生物摄入代谢矿化的多阶段耦合过程，不是"被吃掉"那么简单——先断链降分子量，微生物才接得进去。
敢否定一个常见做法：以为"往 PP 里加一点淀粉就能变可降解"。TPS 是塑化淀粉，本身可降解；但 PP 主链不水解，混进去后 PP 那部分只会碎成微塑料留在环境里，整体并不满足受控堆肥的门限。按 GB/T 19277.1-2025 测的是整材的最终生物分解率，不是"加没加可降解组分"。
四、★ 选型判据表：PP 在可降解包装里只验两件事，其余交降解料
结论先说：这张表第一项就该写"是否真要生物降解"——它是分水岭，决定后面所有判据。PP 在这一栏的答案稳定是"否"，所以 PP 的判据只在后两项（相容剂、单材可回收）。
| 指标 | 门限值（典型） | 验证方法 · 标准号 | 常见失效 | 通行解法 |
|---|
| 是否真需生物降解 | 堆肥/土壤/海水条件下降解，须达受控堆肥门限（生物分解率高位、崩解达标） | GB/T 19277.1-2025（受控堆肥·CO₂ 释放法）；EN 13432:2000（工业堆肥：生物降解 ≥90%/6 月、崩解 ≥90%/12 周）；ASTM D6400-23 | 把"裂解"当"降解"，宣传翻车 | 走 PLA/PBAT/PBS/PHA 体系，不做 PP 主树脂 |
| 相容剂体系（PLA/PBAT 主流） | PLA-g-MAH、PBAT-g-MAH 或 Joncryl ADR 类环氧扩链剂；ADR 4380 以环氧基团连接羟基/羧基 | 共混后测拉伸与断裂伸长率；成核剂 TMC-306 + ADR 协同提结晶与力学 | 相分离、分层、强度掉 | 用降解体系专用相容剂，非 PP 基 |
| PP 基相容剂适用边界 | PP-g-MAH / POE-g-MAH：聚烯烃+尼龙合金 2%~5%；玻纤/矿物填充（硅烷偶联）0.3%~1.5%；工程塑料合金（SMA 类）1%~3%（B 级） | 共混后界面观察 + 力学复测 | 硬塞进 PLA/PBAT 体系，不兼容 | PP 基相容剂只用于 PP/PA、玻纤增强 PP、矿物填充 PP，不用于降解主体系 |
| 单一材质可回收（Mono-PP） | 全 PP 单材多层结构；EVOH 阻隔层 <5% 总重可保留在聚烯烃回收流（B 级） | 回收流相容性评估；结构按单材设计 | 混了不可回收层，进不了聚烯烃流 | 走 Mono-PP，明确告知"可回收 ≠ 可降解" |
| 耐热与热封 | PP 耐热优于 PE，适配热灌装与蒸煮；热封层按起始温度定 | 梯度热封曲线；参照 GB/T 10004-2008 思路 | 误把降解膜当耐蒸煮膜 | 耐热结构用 PP 层，降解层另设 |
| 降解认证 / 检测报告 | 须第三方按现行体系出具 | GB/T 38082-2019（生物降解塑料购物袋）；EN 13432:2000、ASTM D6400-23 | 无报告就宣称"可降解" | 找降解料厂 / 检测机构，不做 PP 端承诺 |
文字版结论：这张表第一列是"该不该用 PP"的一票否决项。 真要降解，PP 出局，主树脂走 PLA/PBAT；只要"环保说法"且要 PP 性能与成本，走 Mono-PP 单一材质可回收——并明确告知这不等同可降解。
五、常见失效与根因：四个现象，三个来自"概念没分清"
结论先说：这四类失效里，有三类的根因是"把三个概念当成一个用"，不是料不好。
失效一：宣称"可降解 PP 袋"，送检过不了。 根因是主树脂用了 PP（或 PP+淀粉），按 GB/T 19277.1-2025 测整材生物分解率不达标。这条路 PP 走不通，硬走就是虚假宣称。
失效二：Mono-PP 袋被回收站拒收。 根因是复合层里混了铝箔、PET 或超量 EVOH（>5% 总重），破坏了聚烯烃单材属性。单材可回收的硬前提是"全 PP 结构 + 阻隔层不超 5%"，超了就进不了聚烯烃回收流。
失效三：PLA/PBAT 膜发脆、热封漏。 根因是 PLA 热变形温度约 55℃、脆性大，没配 PBAT 增韧与合适相容剂。这是降解主体系自己的工艺题，不是 PP 的题。
失效四（敢否定一个常见做法）：以为"加 PP-g-MAH 就能让 PLA/PBAT 兼容 PP"。 PP-g-MAH 的搭桥对象是 PP 与 PA、玻纤、矿物这些——它的极性与 PLA/PBAT 不对口。PLA/PBAT 体系的界面，主流用 PLA-g-MAH、PBAT-g-MAH 与 Joncryl ADR 类环氧扩链剂。把 PP 基相容剂硬塞进降解体系，是白费。
六、验证顺序：先定"降不降"，再定"PP 站哪"
结论先说：验证顺序是"概念定档 → 主树脂验证 → PP 位置验证"三段；顺序反了，最贵的失败落在认证那一步。
`
① 定概念档 问清：要真降解？要单材回收？要生物基说法？
↓ 要真降解 → 直接走降解料，PP 不出主树脂
② 主树脂降解验证 GB/T 19277.1-2025 受控堆肥；EN 13432 / ASTM D6400 对应认证
↓ 生物分解率或崩解不达标 → 退回树脂配比与相容剂
③ 若走 Mono-PP 全 PP 结构确认；EVOH 阻隔层 <5% 总重核对
↓ 混了不可回收层 → 退回复合结构设计
④ 相容剂位置核对 PP 基相容剂只验 PP/PA、玻纤增强 PP、矿物填充 PP
↓ 想进 PLA/PBAT → 退回，换 PLA-g-MAH/PBAT-g-MAH/ADR
⑤ PP 层耐热与热封 梯度热封 + 耐热复测（如涉热灌装/蒸煮）
↓ 不过 → 退回 PP 层档位
⑥ 认证与检测报告 找降解料厂/检测机构出报告，PP 端不做降解承诺
`
最常被跳过的是 ①：没定概念档就先选料，选完才发现"要降解"和"用 PP"只能留一个。跳过 ② 直接做 ⑥ 的一次失败，就是整批认证作废。
七、反向诚实：这几类需求该直接找降解料厂，我们接不住
结论先说：这一节讲"什么时候别找我们"。写清楚，比硬接一张单有用。
| 出现的情况 | 为什么 PP 端接不住 | 该找谁 |
|---|
| 要求真正生物降解（堆肥或土壤条件） | PP 主链 C—C 单键不水解，整材过不了受控堆肥门限 | PLA/PBAT/PBS/PHA 体系，走降解料通道 |
| 要求整膜生产（配方—吹膜—分切—制袋） | 吹膜流道、急冷、收卷是膜厂体系，与造粒线两套装备 | 膜厂 / 制袋厂 |
| 要求降解认证或降解率检测报告 | 认证对象是整个降解制品，责任主体是降解料厂与检测机构 | 降解料厂 / 检测机构 |
| 只是要"环保说法"又要求 PP 性能与成本 | 只能走 Mono-PP 单一材质可回收路线，且这不等于可降解 | 走 Mono-PP 可回收路线，明确告知边界 |
我方不接降解主树脂这一块，也不冒充能接。 把这条线讲在前，客户反而愿意把能接的那段交过来。
能参与的是两处：① 相容剂方向——PP-g-MAH / POE-g-MAH 给 PP/PA 合金、玻纤增强 PP、矿物填充 PP 做界面搭桥（加量按上表 2%~5% / 0.3%~1.5% / 1%~3%）；② 单一材质可回收（Mono-PP）方向——全 PP 单材多层结构，靠 PP 耐热与挺度做热封、结构与热灌装层，阻隔用 <5% 总重的 EVOH。
一条经验：接可降解包装询盘，先问"降解还是回收"。 答"降解"的，指到降解料厂；答"回收 + PP 性能"的，才轮到我们这一步。
八、换料风险清单：共挤与复合，动的是层位不是模具
结论先说：可降解包装的换料风险集中在"共挤层位"和"相容剂体系"两块，跟注塑件的收缩率、浇口是两套清单。
| 要动的项 | 需要确认什么 | 不做会怎样 |
|---|
| 共挤层结构 | 哪层是降解主树脂、哪层是 PP 结构层、阻隔层占比 | 混层导致回收流不认或降解率不达标 |
| 相容剂体系 | 降解体系用 PLA-g-MAH/PBAT-g-MAH/ADR；PP 体系用 PP-g-MAH | 相分离、分层、强度掉 |
| 挤出温度窗口 | PLA 加工窗偏窄，PP 层耐温更高，各层熔体温度不重合 | 降解层热降解、晶点、破膜 |
| 冷却与急冷辊 | 辊温与线速决定结晶与表面 | 雾度上升、热封窗口收窄 |
| EVOH 阻隔层占比 | 单材回收要求 <5% 总重 | 超量进不了聚烯烃回收流 |
| 热封层定位 | PP 结构层做热封，起始温度独立定 | 上机封不住或封穿 |
| 验证顺序 | 概念定档 → 主树脂降解验证 → Mono-PP 核对 → 相容剂位置 → 耐热热封 → 认证报告 | 风险全压到认证那一步爆发 |
文字版结论：换料要动的是共挤层位、相容剂体系、温度窗口、EVOH 占比四块，最该先谈的还是验证顺序。跳过概念定档直接选料，就是用整批认证的成本去发现一个一开始就能说清的边界。
九、一页纸汇报对照表：可降解包装选型可直接贴进 PPT
结论先说：判断标准只有一条——技术员拿这张表，一次会议里能不能把"降解还是回收"定下来。
| 场景 | 推荐路线 | 关键指标 | 验证标准 | 需先确认的条件 |
|---|
| 真正生物降解袋（堆肥/土壤） | PLA/PBAT 共混 + 专用相容剂 + TPS 降本 | 生物分解率、崩解率、拉伸 20~30 MPa | GB/T 19277.1-2025；EN 13432:2000；ASTM D6400-23 | 降解环境（工业/家庭/土壤）、认证等级 |
| 生物降解购物袋 | 同上，按袋型定强度 | 拉伸、封口、落镖 | GB/T 38082-2019 | 是否食品接触、承重 |
| 单一材质可回收包装（Mono-PP） | 全 PP 多层结构 + EVOH <5% | 回收流相容、耐热、热封 | 聚烯烃回收流评估 | 阻隔目标值、是否宣称"可降解"（否） |
| PP 结构复合层（耐热/挺度） | PP 层做热封与结构，降解层另设 | 耐热、挺度、热封起始温度 | 梯度热封 + 耐热复测 | 热灌装/蒸煮温度 |
| PP/PA 或玻纤增强 PP 相容 | PP-g-MAH / POE-g-MAH 2%~5% 或 0.3%~1.5% | 界面、力学 | 共混后力学复测 | 是否与降解体系混用（否） |
文字版结论：别把"降解、回收、生物基"塞进一句"环保"里——三件事各自给门限、各自给标准。最有用的是最后一列，它决定报出去的话能不能兑现。
十、这个方向上，我们接的是哪一段
这个方向上最集中的误读是把"光氧裂解"当"生物降解"，以及把 Mono-PP 可回收当成可降解。公开技术资料把降解讲得很直接：生物降解靠主链上的水解敏感位点被微生物代谢矿化，PP 的 C—C 主链没有这个位点，只做光氧老化裂解、碎成微塑料，不满足受控堆肥门限。判据写在标准里：受控堆肥按 GB/T 19277.1-2025 测 CO₂ 释放，工业堆肥按 EN 13432:2000 要求生物降解 ≥90%（6 月内）、崩解 ≥90%（12 周内），购物袋按 GB/T 38082-2019，北美标签按 ASTM D6400-23。
宁波市科隆新材料有限公司在这个方向上常供的是改性PP 粒子里的两段：一是相容剂方向——PP-g-MAH / POE-g-MAH 给 PP/PA 合金、玻纤增强 PP、矿物填充 PP 做界面搭桥，加量按聚烯烃+尼龙 2%~5%、玻纤/矿物填充 0.3%~1.5%、工程塑料合金 1%~3% 的公开口径；二是单一材质可回收（Mono-PP）方向——全 PP 单材多层结构，靠 PP 耐热与挺度做热封、结构与热灌装层，阻隔用 <5% 总重的 EVOH，并明确告知"可回收 ≠ 可降解"。降解主树脂（PLA/PBAT/PBS/PHA）与整膜生产、降解认证这三段不在我们能接的范围内。
常见问答
问：PP 能不能做成可降解包装？
答：做不出真正的生物降解。PP 主链 C—C 单键不水解，按 GB/T 19277.1-2025 测整材生物分解率过不了门限。要真降解走 PLA/PBAT 体系；要 PP 性能又想"环保"，走 Mono-PP 单一材质可回收，并清楚这是回收不是降解。
问：PP-g-MAH 能不能让 PLA/PBAT 兼容 PP？
答：不对口。PP-g-MAH 的搭桥对象是 PP 与 PA、玻纤、矿物；PLA/PBAT 体系的界面主流用 PLA-g-MAH、PBAT-g-MAH 与 Joncryl ADR 类环氧扩链剂。硬塞 PP 基相容剂不解决问题。
问：Mono-PP 是不是就等于可降解？
答：不是。Mono-PP 解决的是回收分拣——全 PP 结构 + EVOH <5% 总重，能进聚烯烃回收流；它不会在堆肥或土壤里消失。两个概念正交。
| 工况 | 关键判据 | 科隆常规供应方向 |
|---|
| PP/PA 合金、玻纤增强 PP、矿物填充 PP 相容 | PP-g-MAH / POE-g-MAH 加量 2%~5% / 0.3%~1.5% / 1%~3% | 改性PP 相容剂方向 |
| 单一材质可回收（Mono-PP）包装 | 全 PP 结构、EVOH <5% 总重、耐热与热封 | 改性PP 单材多层结构方向 |
| 真正生物降解包装 | 受控堆肥门限、崩解达标 | 不接，指降解料厂 / 检测机构 |
想提醒一句：可降解包装出问题，最常见的错法是先换料。裂解当降解、回收当降解、PP 基相容剂硬塞降解体系——每一条的原因都不止一个。先定概念档，再选料；顺序反了，往往换了几轮还在原地。
十一、最后说三句
第一，先分清三个概念，再谈材料。 可降解管结局、可回收管去路、生物基建出身——PP 只沾后两件的一角，第一件不沾。
第二，PP 在可降解包装里只站两处。 相容剂（PP-g-MAH 给 PP/PA、玻纤、矿物搭桥），以及单一材质可回收（Mono-PP，EVOH <5%）。降解主树脂是 PLA/PBAT 的活。
第三，"裂解"不是"降解"，"可回收"不是"可降解"。 两句话能省掉的返工和翻车，比任何一次比价都多。
关于我们
样品寄出去之后，我们一般还会多问一句："打算怎么试？"
因为试法不对，好料也能试出坏结果。薄壁件的干燥、玻纤料的模温和螺杆、阻燃料的停留时间——任何一项没到位，结论都会跑偏。
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 kind of PP is used for degradable packaging composite layers? Let's clarify one thing first: the main resins for degradable packaging are PLA, PBAT, PBS, PHA, and thermoplastic starch, not PP. This article will first distinguish between the three concepts of degradable, recyclable, and bio-based, then explain the real role of PP in the two areas of compatibilizers and single-material recyclability, and specify which types of orders should go to degradable material manufacturers.
- Comparison of differences: The main line of this article distinguishes three concepts ‘PP real two positions’, each of AE0/AE1/AE2/A48 follows its own line, without overlapping
Give me a biodegradable PP.
This sentence can be heard almost every week. The first half wants it to 'rot in the soil,' while the second half wants the PP to have stiffness, heat resistance, and be cheap—these two things, when applied to the same film, contradict each other.
Let's put the key takeaway of this article at the very beginning: the main resins for degradable packaging are PLA, PBAT, PBS, PHA, and thermoplastic starch (TPS), not PP. The molecular backbone of PP consists of C—C single bonds, with no hydrolysis-sensitive sites, and it does not have biodegradability—it can only undergo photo-oxidative aging and fragmentation (breaking into microplastics). That's not 'degradation,' it's 'fragmentation.' Mistaking fragmentation for degradation is the most common misconception in the entire industry, and it's the point that this article wants to address first.
So this article doesn’t insist that PP can enter biodegradable packaging—what PP is used in biodegradable packaging? The answer isn’t in the main PP resin, but in the two lines of compatibilizers and single-material recyclability. On this track, only two positions truly hold up—towards compatibilizers and towards single-material recyclable (Mono-PP). First, let’s clarify the three concepts that are often mixed together, then we’ll talk about these two areas.
1. The six conditions of degradable packaging: the two dimensions of medium and lifespan determine whether it should degrade or be recycled
Conclusion first: In six dimensions, the ones that should be decided first are 'medium' and 'lifespan' — the medium determines whether it can come into contact with a degrading environment, and the lifespan determines whether it goes through 'use and discard then degrade' or 'long-term reuse then recycle.' If this dimension is not decided, everything else is pointless.
| Dimension | Actual working conditions of biodegradable packaging | Requirements for the materials |
|---|
| Temperature | Typical composting conditions: 58°C level; home composting fluctuates at room temperature; hot filling/cooked items reach 100°C; cold chain −18°C | Degradable resins generally have lower heat resistance than PP; PP series heat-resistant grades can be used for thermal sealing and structural layers. |
| Load | Shopping bags and express delivery bags can carry from a few kilograms to more than ten kilograms; composite films rely on layer structure and heat sealing to bear weight. | Stretch and sealing strength, set thresholds according to bag type |
| Medium | Compost (high moisture, microorganisms), soil, seawater; contents: oils, acids and bases, water content | Whether it can enter a degradable environment is a watershed. |
| Lifespan | Disposable degradable items are designed to 'degrade a few weeks to a few months after disposal'; reusable items are designed to 'be recycled after several years of use'. | Degradable parts should disintegrate quickly, while recyclable parts should age slowly. |
| Appearance | Transparency, crispness, printability | PLA has high transparency, similar to PET; PBAT feels similar to PE |
| Compliance | Comply with degradation certification (GB/T 19277.1-2025 controlled composting, GB/T 38082-2019 shopping bags, EN 13432, ASTM D6400) or recycling labels (polyolefin recycling stream) | Certification is a ticket to entry, not an extra credit. |
Note: The magnitudes of temperature, load, and appearance come from publicly available industry data (Grade B) and are used to illustrate the magnitudes; specific thresholds must be written into the acceptance criteria and measured according to the corresponding standards. The names, years, and applicable scopes of the degradation certification standards have been verified one by one (see the memo at the end).
The two series that are easiest to confuse are 'medium can biodegrade' and 'long enough lifespan.' The mission of a PLA/PBAT bag is 'use it up and compost it,' it doesn't need to last three years; the mission of a PP turnover box is 'use it for three years and then enter the recycling stream,' it doesn't need to rot in the soil. One is designed to disappear, the other is designed not to disappear — these two lines fundamentally go in opposite directions.
2. First, separate the three concepts that are often mixed up: degradable, recyclable, and bio-based are not the same thing.
Conclusion first: the mistake that this article aims to correct is using these three words as synonyms. They refer to three different things — 'whether it can be eaten by microorganisms,' 'whether it can be recycled,' and 'whether the raw material comes from plants and animals or petroleum.' PP only touches a corner of the latter two, not the first one.
| Concept | What is being said | Typical materials | Can the PP fit in? |
|---|
| Degradable (biodegradable) | Under conditions such as compost/soil/seawater, it is metabolized and mineralized by microorganisms, eventually turning into CO₂, water, and biomass | PLA, PBAT, PBS, PHA, thermoplastic starch (TPS) | Does not stand. The main chain of PP has C—C single bonds with no hydrolyzable sites, and it does not have biodegradability. |
| Recyclable (circular) | After use, sort, clean, and remelt into pellets, returning to the polyolefin stream | PP, PE, and single-material multilayer structures (Mono-PP) | Holds up. PP has better heat resistance than PE, suitable for hot filling; single-material structure solves sorting issues. |
| Bio-based (raw material source) | Monomers come from renewable biomass, which does not equal 'biodegradable' | Bio-based PE, bio-based PP, PLA (partially bio-based) | Partially related. Bio-based PP is still a non-degradable polyolefin, going through the recycling channel, not the degradation channel. |
Text version conclusion: 'Bio-based' refers to origin, 'biodegradable' refers to the end, and 'recyclable' refers to the path—three things are orthogonal. A 'bio-based PP' bag originates from plants, ends up not biodegradable, and its path is recycling. Reading 'bio-based' as 'biodegradable' is the second common misunderstanding.
This section is the part of this article that does not overlap with the AE0/AE1/AE2/A48 series: those four articles respectively discuss the working conditions and modifications of films, heat sealing, air columns, and agricultural films, while this article only focuses on the 'concept differentiation of PP real two positions' and does not cover any production line.
3. Comparison of Degradable Resin System Parameters: PLA/PBAT is the main focus, PP is not part of the main resin
Conclusion first: Three types of degradable resins (PLA, PBAT, PBS/PHA) combined with TPS form the main body of degradable packaging; PP is not on the list of main resins, and only appears in 'interface' and 'single-material structure.' The table below is for providing the client with scale criteria, all marked as Grade B.
| Resin | Source / Type | Key performance level (B level) | Position in the packaging |
|---|
| PLA | Bio-based thermoplastic polyester | High transparency, crisp, gloss similar to PET; high brittleness, low elongation at break, heat distortion temperature about 55°C | One of the main resins, often requires toughening and heat resistance modification |
| PBAT | Petroleum-based aliphatic-aromatic copolyester | Elongation at break >600%, tear-resistant, hand feel similar to PE bag | One of the main resins, provides toughness |
| PBS / PBSA | Aliphatic polyester | Heat resistance is slightly better than PLA | Heat-resistant degradable parts, tableware |
| PHA / PHBV | Microbial synthesis of polyesters | Seawater is also degradable, but the cost is high | Special degradation scenario |
| TPS (Thermoplastic Starch) | Starch Glycerol plasticization | Reduce costs, increase speed, usually add 10%~30% | Filling reduces costs |
| PP | Polyolefin | Stiffness, heat resistance, low cost; non-degradable | Not in the main resin; only in the compatibilizer and recyclable monomer structure |
According to publicly available technical information (Class B), in mainstream formulations, PLA and PBAT are blended at a mass ratio of 3:7 to 5:5, with compatibilizers added to assist dispersion. The tensile strength of the composite material can reach 20–30 MPa (close to the level of low-density polyethylene bags). To reduce costs and speed up production, an additional 10%–30% TPS or a small amount of calcium carbonate is often added. The degradation mechanism is a multi-stage coupled process: hydrolytic chain scission → microbial ingestion and metabolic mineralization; it is not as simple as 'being eaten'—the chains break down first to lower molecular weight, then microbes can process it.
Dare to deny a common practice: thinking that 'just adding a little starch to PP will make it biodegradable.' TPS is plasticized starch, which is itself biodegradable; but the main chain of PP does not hydrolyze, so the PP portion will only break down into microplastics and remain in the environment, and overall it does not meet the threshold for controlled composting. According to GB/T 19277.1-2025, what is measured is the final biodegradation rate of the whole material, not whether biodegradable components have been added or not.
4. ★ Selection Criteria Table: For PP in biodegradable packaging, only two things are tested, the rest are handed over to biodegradable materials.
Conclusion first: The first item on this table should be "Does it really need to be biodegradable"—it is the watershed that determines all the subsequent criteria. The answer for PP in this column is consistently "No," so PP's criteria only apply to the last two items (compatibilizer, recyclability of the single material).
| Indicator | Threshold Value (Typical) | Verification Method · Standard Number | Common Failures | Common solution |
|---|
| Is biodegradability really necessary? | Degradation under compost/soil/seawater conditions must reach the controlled composting threshold (high biodegradation rate, disintegration standard met) | GB/T 19277.1-2025 (Controlled Composting·CO₂ Emission Method); EN 13432:2000 (Industrial Composting: Biodegradation ≥90%/6 months, Disintegration ≥90%/12 weeks); ASTM D6400-23 | Mistaking 'cracking' for 'degradation', the publicity backfired | Follow the PLA/PBAT/PBS/PHA system, do not use PP as the main resin |
| Compatibilizer system (mainstream PLA/PBAT) | PLA-g-MAH, PBAT-g-MAH, or Joncryl ADR type epoxy chain extenders; ADR 4380 connects hydroxyl/carboxyl groups with epoxy groups | Measure tensile strength and elongation at break after blending; nucleating agent TMC-306 ADR synergistically enhances crystallization and mechanical properties | Phase separation, layering, strength loss | Use a compatibilizer specific to the degradation system, not PP-based |
| PP base compatibilizer applicable boundaries | PP-g-MAH / POE-g-MAH: Polyolefin-nylon alloy 2%~5%; glass fiber/mineral filled (silane coupling) 0.3%~1.5%; engineering plastic alloy (SMA type) 1%~3% (Grade B) | Interface observation after blending Mechanical retesting | Forcibly stuffed into the PLA/PBAT system, incompatible | PP base compatibilizer is only used for PP/PA, glass fiber reinforced PP, and mineral-filled PP, and is not used for degrading the main system. |
| Single-material recyclable (Mono-PP) | All-PP single-material multi-layer structure; EVOH barrier layer <5% of total weight can be retained in the polyolefin recycling stream (Grade B) | Recycle flow compatibility assessment; structure designed according to individual materials | Mixed with non-recyclable layers, it cannot enter the polyolefin stream | Use Mono-PP, clearly indicate 'recyclable ≠ biodegradable' |
| Heat Resistance and Heat Sealing | PP has better heat resistance than PE, suitable for hot filling and cooking; the heat-sealing layer is determined according to the starting temperature. | Gradient heat sealing curve; referring to the approach of GB/T 10004-2008 | Mistakenly treated a degradable film as a steam-cooking resistant film | PP layer for heat-resistant structure, with a separate degradation layer |
| Degradation Certification / Test Report | Must be issued by a third party according to the current system | GB/T 38082-2019 (biodegradable plastic shopping bags); EN 13432:2000, ASTM D6400-23 | Claiming 'biodegradable' without a report | Looking for a biodegradable material factory / testing agency, not making promises on the PP side |
Text version conclusion: The first column of this table is the veto item of 'whether or not to use PP.' If degradation is really required, PP is out, and the main resin will be PLA/PBAT; as long as it is for 'environmental claims' and requires PP performance and cost, use Mono-PP single material recyclable — and clearly inform that this is not equivalent to degradable.
5. Common Failures and Root Causes: Four Phenomena, Three Originate from 'Concepts Not Clearly Differentiated'
Conclusion first: Among these four types of failures, the root cause of three of them is 'treating three concepts as one,' not poor material.
Failure 1: Claiming 'degradable PP bags' fails inspection. The root cause is that the main resin uses PP (or PP starch), and according to GB/T 19277.1-2025, the overall material's biodegradability does not meet the standard. This path for PP is unfeasible, forcing it would be a false claim.
Failure 2: Mono-PP bags were rejected by the recycling bin. The root cause is that the composite layer contains aluminum foil, PET, or an excessive amount of EVOH (>5% of the total weight), which destroys the properties of the polyolefin monomaterial. The strict prerequisite for a material to be recyclable as a monomaterial is 'all-PP structure, with barrier layers not exceeding 5%'; if it exceeds this, it cannot enter the polyolefin recycling stream.
Failure 3: PLA/PBAT film becomes brittle and has heat seal leakage. The root cause is that PLA has a heat distortion temperature of about 55℃ and is very brittle, and PBAT was not added for toughening along with a suitable compatibilizer. This is a process issue of the main degraded system itself, not a problem with PP.
Failure four (daring to deny a common practice): Thinking that adding PP-g-MAH can make PLA/PBAT compatible with PP. The bridging targets of PP-g-MAH are PP and PA, glass fiber, minerals——its polarity does not match PLA/PBAT. For the interface of the PLA/PBAT system, mainstream practice uses PLA-g-MAH, PBAT-g-MAH, and Joncryl ADR-type epoxy chain extenders. Forcing a PP-based compatibilizer into a degradable system is a waste.
6. Verification sequence: first determine 'whether it goes down,' then determine 'where the PP stands.'
Conclusion first: the verification sequence is in three stages - 'concept finalization → main resin verification → PP position verification'; if the order is reversed, the most expensive failure occurs at the certification step.
`
① Define concept profile Ask clearly: Does it need true degradability? Single-material recycling? Bio-based claim?
↓ For real degradation → go directly with degradable material, PP does not produce the main resin
② Main Resin Degradation Verification GB/T 19277.1-2025 Controlled Composting; EN 13432 / ASTM D6400 Corresponding Certification
↓ Biodegradability or disintegration does not meet the standard → Return to resin ratio and compatibilizer
③ If using Mono-PP, confirm the entire PP structure; check that EVOH barrier layer is less than 5% of total weight
↓ Mixed with the non-recyclable layer → Revert to composite structure design
④ Compatibilizer Position Check PP-based compatibilizer is only tested for PP/PA, glass fiber reinforced PP, and mineral-filled PP
↓ Want to enter PLA/PBAT → Return it, switch to PLA-g-MAH/PBAT-g-MAH/ADR
⑤ PP layer heat resistance and heat sealing Gradient heat sealing Heat resistance retesting (e.g., involving hot filling/steaming)
↓ However → Return to PP layer gear
⑥ Certification and Testing Report Obtain reports from degradable material manufacturers/testing institutions; the PP side does not make degradation promises
`
The one most often skipped is ①: choosing the material before defining the concept, only to realize after selection that 'biodegradable' and 'using PP' cannot both be used. Skipping ② and going straight to ⑥ results in a single failure, causing the entire batch certification to be invalid.
7. Reverse honesty: These types of demands should be directly directed to degraded material factories; we can't handle them.
Conclusion first: This section talks about 'when not to contact us.' Writing it clearly is more useful than just processing an order.
| The situation that occurred | Why can't the PP end connect? | Who should I find |
|---|
| Requires true biodegradability (compost or soil conditions) | The C—C single bonds in the main chain of PP do not hydrolyze, and the intact material cannot pass the controlled composting threshold. | PLA/PBAT/PBS/PHA system, taking the biodegradable material route |
| Require complete film production (formulation—film blowing—slitting—bag making) | Blown film die, rapid cooling, and winding are part of the film factory system, separate from the two sets of equipment for the pelletizing line. | Film Factory / Bag-Making Factory |
| Request for degradation certification or degradation rate test report | The certification target is the entire degradable product, and the responsible parties are the degradable material manufacturer and the testing agency. | Degradable Material Factory / Testing Institution |
| Just want 'environmentally friendly wording' while also requiring PP performance and cost | It can only follow the Mono-PP single material recyclable route, and this does not mean it is biodegradable. | Follow the Mono-PP recyclable route and clearly communicate the boundaries |
We do not handle the degradation of the main resin, nor do we pretend that we can. By explaining this upfront, the customer is actually more willing to hand over the part that we can handle.
There are two areas of involvement: ① Compatibilizer direction — PP-g-MAH / POE-g-MAH for PP/PA alloys, glass fiber reinforced PP, and mineral-filled PP to bridge interfaces (dosage according to the above table: 2%~5% / 0.3%~1.5% / 1%~3%); ② Single-material recyclable (Mono-PP) direction — all-PP single-material multilayer structure, relying on PP's heat resistance and stiffness for heat sealing, structural and hot-fill layers, with less than 5% of total weight EVOH for barrier purposes.
A piece of advice: When receiving inquiries about biodegradable packaging, first ask 'biodegradable or recyclable.' If the answer is 'biodegradable,' refer them to the biodegradable material factory; if the answer is 'recyclable PP performance,' that's when it comes to our part.
8. Material Change Risk List: Co-extrusion and lamination involve changing layers, not molds
Conclusion first: The risk of changing materials in biodegradable packaging is concentrated in the 'co-extrusion layer' and the 'compatibilizer system,' which are separate from the shrinkage rate and gate of injection-molded parts.
| Items to move | What needs to be confirmed | What will happen if I don't do it? |
|---|
| Co-extruded layer structure | Which layer is the degradable main resin, which layer is the PP structural layer, and the proportion of the barrier layer | Mixed layers cause the recycling stream to be unrecognizable or the degradation rate to be below standard |
| Compatibilizer system | The degradation system uses PLA-g-MAH/PBAT-g-MAH/ADR; the PP system uses PP-g-MAH | Phase separation, layering, strength loss |
| Extrusion temperature window | The PLA processing window is relatively narrow, the PP layer has a higher temperature resistance, and the melt temperatures of each layer do not overlap. | Degradation layer thermal degradation, crystallization point, membrane rupture |
| Cooling and Quenching Roll | Roll temperature and line speed determine crystallization and surface | Increased haze, narrowed heat-sealing window |
| Proportion of EVOH barrier layer | Single material recovery requirement <5% of total weight | Excess cannot enter the polyolefin recycling stream |
| Heat-sealing layer positioning | The PP structural layer is heat sealed, and the starting temperature is independently set | Cannot be sealed when installed or sealed through |
| Verification order | Concept finalization → Main resin degradation verification → Mono-PP check → Compatibilizer placement → Heat-resistant heat sealing → Certification report | The risk is fully concentrated to explode at the certification stage |
Text Version Conclusion: The aspects that need to be adjusted when changing materials are the co-extrusion layer, compatibilizer system, temperature window, and EVOH proportion. What should be discussed first is still the verification sequence. Skipping conceptual positioning and directly selecting materials means using the cost of certifying an entire batch to discover a boundary that could have been clarified from the start.
9. One-page report comparison table: biodegradable packaging options can be directly pasted into the PPT
Conclusion first: There is only one criterion for judgment — whether the technician can use this table to decide 'degrade or recycle' in a single meeting.
| Scene | Recommended Route | Key indicators | Verification Standard | Conditions that need to be confirmed first |
|---|
| Truly Biodegradable Bags (Compost/Soil) | PLA/PBAT Blending Special Compatibilizer TPS Cost Reduction | Biodegradability, disintegration rate, tensile strength 20~30 MPa | GB/T 19277.1-2025; EN 13432:2000; ASTM D6400-23 | Degradation environment (industrial/home/soil), certification level |
| Biodegradable shopping bag | Same as above, determine strength according to bag type | Stretching, sealing, dropping darts | GB/T 38082-2019 | Whether food contact, load-bearing |
| Single-material recyclable packaging (Mono-PP) | All PP multi-layer structure EVOH <5% | Recycled, flow-compatible, heat-resistant, heat-sealable | Polyolefin Recycling Stream Assessment | Barrier target value, whether 'biodegradable' is claimed (No) |
| PP structural composite layer (heat-resistant/stiffness) | The PP layer is used for heat sealing and structure, while the degradable layer is set separately. | Heat resistance, stiffness, heat seal initiation temperature | Gradient heat sealing Retest for heat resistance | Hot filling/sterilization temperature |
| PP/PA or glass fiber reinforced PP compatible | PP-g-MAH / POE-g-MAH 2%~5% or 0.3%~1.5% | Interface, Mechanics | Mechanical retesting after blending | Whether to mix with the degradation system (No) |
Text version conclusion: Don't lump "degradation, recycling, bio-based" into one 'eco-friendly' term—each of the three should have its own threshold and its own standard. The most useful part is the last column, as it determines whether what is reported can be delivered.
10. In this direction, which segment are we connected to?
The most common misunderstanding in this area is mistaking 'photochemical oxidation cleavage' for 'biodegradation,' and treating recyclable Mono-PP as degradable. Public technical materials explain degradation quite directly: biodegradation relies on hydrolysis-sensitive sites on the main chain being metabolized and mineralized by microorganisms, while the C—C main chain of PP lacks this site, only undergoing photo-oxidative aging and cleavage into microplastics, which does not meet the controlled composting thresholds. The criteria are written in the standards: controlled composting measures CO₂ release according to GB/T 19277.1-2025, industrial composting requires ≥90% biodegradation (within 6 months) and ≥90% disintegration (within 12 weeks) according to EN 13432:2000, shopping bags follow GB/T 38082-2019, and North American labeling follows ASTM D6400-23.
Ningbo Kelong New Materials Co., Ltd. commonly supplies two types of modified PP particles in this direction: first, for the compatibilizer direction—PP-g-MAH / POE-g-MAH, which serve as interfacial bridges for PP/PA alloys, glass fiber-reinforced PP, and mineral-filled PP, with recommended additions based on public benchmarks: 2%~5% for polyolefin/nylon, 0.3%~1.5% for glass fiber/mineral-filled, and 1%~3% for engineering plastic alloys; second, for the single-material recyclable (Mono-PP) direction—whole PP single-material multilayer structures, using PP for heat resistance and rigidity to form heat-sealable, structural, and hot-fill layers, with barrier layers containing less than 5% of total weight EVOH, and clearly indicating that 'recyclable ≠ biodegradable.' The three areas of degradable main resin (PLA/PBAT/PBS/PHA), whole-film production, and degradation certification are beyond our scope.
Frequently Asked Questions
Question: Can PP be made into biodegradable packaging?
Answer: True biodegradation cannot be achieved. The C—C single bonds in the PP main chain do not hydrolyze, so according to GB/T 19277.1-2025, the overall material biodegradation rate does not meet the threshold. To achieve real degradation, one should use the PLA/PBAT system; if PP performance is desired along with an 'environmentally friendly' claim, Mono-PP single material can be used, which is recyclable, with the clear understanding that this is recycling, not degradation.
Question: Can PP-g-MAH make PLA/PBAT compatible with PP?
Answer: It does not match. The bridging target of PP-g-MAH is PP with PA, glass fiber, and minerals; the mainstream interface modifiers for the PLA/PBAT system are PLA-g-MAH, PBAT-g-MAH, and Joncryl ADR type epoxy chain extenders. Forcibly using PP-based compatibilizers does not solve the problem.
Q: Does Mono-PP equal biodegradable?
Answer: No. Mono-PP addresses recycling sorting — with an all-PP structure and EVOH <5% of total weight, it can enter the polyolefin recycling stream; it will not disappear in compost or soil. The two concepts are orthogonal.
| Operating condition | Key criterion | Cologne regular supply direction |
|---|
| PP/PA alloy, glass fiber reinforced PP, mineral filled PP compatible | PP-g-MAH / POE-g-MAH Additional amount 2%~5% / 0.3%~1.5% / 1%~3% | Direction of modified PP compatibilizer |
| Single-material recyclable (Mono-PP) packaging | All PP structure, EVOH <5% of total weight, heat resistance and heat sealing | Direction of Modified PP Single-Material Multilayer Structure |
| Truly biodegradable packaging | Controlled composting threshold, disintegration meets standards | Not accepting, refers to degradation material plants / testing institutions |
Just a reminder: When biodegradable packaging has problems, the most common mistake is to change the material first. Treating cracking as degradation, treating recycling as degradation, forcefully adding PP matrix compatibilizer into the degradation system—each of these has more than one reason. First define the conceptual framework, then choose the material; if the order is reversed, after several rounds of changes, you'll often still be in the same place.
Eleven, finally say three sentences
First, clarify three concepts before discussing the materials. Degradable pipes are about their end-of-life, recyclable pipes are about their path after use, and bio-based construction is about their origin—PP is only related to the last two, not the first.
Second, PP only plays two roles in biodegradable packaging. Compatibilizers (PP-g-MAH bridging PP/PA, glass fiber, minerals) and single-material recyclables (Mono-PP, EVOH <5%). The main degradable resins are PLA/PBAT.
Thirdly, 'cracking' is not 'degradation,' and 'recyclable' is not 'biodegradable.' The rework and mistakes that can be avoided by these two sentences are more than any price comparison.
About Us
After sending out the sample, we usually ask one more question: 'How do you plan to test it?'
Even good material can produce bad results if the testing method is incorrect. Drying of thin-walled parts, mold temperature and screw settings for glass fiber materials, retention time for flame-retardant materials—if any of these are not properly managed, the conclusion will be skewed.
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.
