上个月，一个做徒步鞋的客户来问鞋大底用什么料。
他想把一款橡胶底换成改性尼龙体系的弹性体，理由只有两个字：减重。
寄样的时候他附了一张纸条，上面用圆珠笔写了三个数：DIN 磨耗 120、湿态止滑 0.42、硬度 62。
电话里他说得很直接："我就要这三个数，别的不看。"
我问他第一句：这三个数是谁给的。他停了两秒，说，上一家料厂。
我说：这三个数不是一个维度上的三个数，它们是两张互相拆台的账。
这篇就讲清大底料的三件事：耐磨和防滑为什么会打架、三条路线各自让掉什么，以及什么样的鞋根本不该动大底。
一、大底的失效，八成不是"磨穿"，是"先滑倒"
先把大底干的活说清楚。
鞋底分三层：中底管缓冲和回弹，大底管抓地和耐磨，鞋底片是夹在中间、或者直接贴地的那一片。
大底要同时做四件事：把地面抓住、把磨耗扛住、把脚撑住、把形留住。
四件事里，消费者只会投诉两件：磨得快、滑得慌。
而这两件，在材料上是一对反向变量。
为什么反向——止滑靠"贴"。
材料越软，踩下去的时候微观凸起嵌进地面的深度越深，真实接触面积越大，摩擦力越大。
耐磨靠"扛"。
材料越硬、结晶度越高，被地面切削掉的材料就越少。
一个要软，一个要硬。这就是大底料的第一性矛盾。
一句话：大底的选材，本质上是在"贴得住"和"扛得住"之间找一个位置。
而这个位置不是固定的，它随温度走。
橡胶在常温下软，湿地止滑好；到了零下十几度，它变硬变脆，止滑和耐折一起掉。
尼龙弹性体在这一段的模量变化比橡胶平缓，低温是它的机会。
但常温那一段的硬度和耐磨上限，它又不像橡胶那么随心。
所以真正该问的，不是"哪种料更好"。
该问的是：这双鞋，主要在什么温度的地面上跑。
再回到开头那张纸条。
那位客户把 DIN 磨耗、止滑系数、硬度写在一行里，当成一张验收单。
问题是这三个数的来源完全不同：磨耗是台架上的体积损失，止滑是摩擦系数，硬度是压痕。
它们是三条独立的曲线，而且在多数配方里，一条往上走，另一条就要往下让。
这三条曲线怎么摆，才是选大底料真正要谈的事。
二、工况六维：大底到底被什么夹住
把大底的工况拆成六个维度，每一维都给一个可核对的量。
温度。 这是第一维度，也是最容易被跳过的一维。
南方城市通勤鞋，最低可能只到 0℃；北方冬季户外，-20℃ 是常态，-30℃ 也要算进考核范围。
温度决定两件事：材料的模量，和材料的耐折寿命。
载荷与磨耗。 一个人 70 公斤，正常走一步，单脚承重在 1 到 1.5 倍体重之间；跑步落地的峰值可以到 3 倍。
换算一下：70 公斤的人跑起来，落地那一瞬大底前掌要接住两百公斤上下的力。
这种力不是一次，是每次落地都来一遍。
磨耗的量化指标是 DIN 磨耗，单位是立方毫米——数值越小越耐磨。
介质。 水、雪、冰、融雪盐、油污、洗涤剂，这几样都要过一遍。
冰是特殊的一档，它不是固体摩擦，是"表面一层水膜"上的润滑。
为什么会这样——冰面摩擦生热会融出一层微米级的水膜，材料实际上是在水上滑。
所以"硬"在冰面上完全不是优势。
真正管用的是滞后损失和真实接触面积，也就是材料被压下去又弹回来的那部分能量损耗。
寿命。 一双通勤鞋按 800 公里算，一双越野鞋按 500 公里算。
800 公里大约是 100 万到 130 万步。
每一步都是一次弯折、一次切削，累加起来才是真正的考核量。
外观。 浅色和透明大底看的是黄变和雾度。这在大底上是硬指标，因为它整片露在外面。
合规与环保。 接触地面与皮肤，涉及消费品安全与挥发物；这两年还多了一条可回收性与单一材质的方向。
六维摆在一起，会看到一个结论：这六维不是并列的，是串联的。
温度一变，模量就变；模量一变，止滑就变；止滑要补，硬度就要降；硬度一降，磨耗就上来。
它们是一根链条，动一环，后面全跟着动。
三、三条路线并列：各自的强项和要交的学费
| 路线 | 止滑（干 / 湿 / 冰） | 耐磨 | 低温耐折 | 密度 | 与中底结合 | 常见定位 |
|---|
| 硫化橡胶（NR / SBR / BR） | 好 / 好 / 中 | 中 | 中，低温变硬 | 高 | 需界面处理 | 主力大底 |
| TPU 体系 | 好 / 中 / 中 | 好 | 中 | 中 | 可直接包胶 | 运动、休闲 |
| 尼龙弹性体（TPAE / PEBA） | 中 / 好 / 好 | 中，配方可调 | 好 | 低 | 可直接包胶 | 轻量、冰面、高回弹底 |
看这张表，重点不在哪一列最强，在每一列都要交学费。
橡胶的学费是重量和低温。
同一只 42 码的鞋，橡胶大底通常比尼龙弹性体大底重几十克。几十克在整鞋上就是"轻量款"和"普通款"的分野。
TPU 的学费是低温。
常温下它几乎全能，但到 -20℃ 以下，模量爬得快，止滑和耐折一起掉。
尼龙弹性体的学费是耐磨和成本。
它的硬段是聚酰胺，结晶提供了耐磨的底子；但分子链里的聚醚软段为了让冰面贴得住，本身就偏软。
耐磨这条线要往上走，通常只有两条路。
一条是提高硬段比例，代价是低温性能往回退。
另一条是靠改性体系去补，代价是要小心外观和界面。
这里有一条容易被忽略的：尼龙弹性体不是"更强的 EVA"，也不是"更轻的橡胶"。
它是另一套体系——加工窗口、模具、回收路径都不一样。
拿橡胶的模具和工艺直接上尼龙弹性体，多半会卡在收缩和粘接这两道。
所以换料这件事，真正要评估的从来不是"料够不够好"，是"这双鞋愿不愿意为哪一列让路"。
四、选型判据表（这一页建议收藏）
门限值是方向性建议，不是验收标准。实际数值必须由鞋型、鞋码、目标市场和使用温度实测确定。
| 指标 | 方向性门限 | 验证方法 / 标准 | 常见失效 | 通行解法 | 对应助剂体系 |
|---|
| DIN 磨耗 | 按定位定，通勤类建议 150 mm³ 以内 | GB/T 9867 / ISO 4649 | 底纹磨平、磨露中底 | 提高硬段比例或改性体系 | 耐磨填料（视体系） |
| 干态止滑 | 平整钢板 COF 0.7 量级起 | GB/T 3903.6 整鞋防滑 | 地面起步打滑 | 提升软段柔性 + 花纹 | — |
| 湿态止滑 | 水膜条件下 COF 0.4 以上 | 同上，加皂液条件 | 雨天、瓷砖面打滑 | 提高滞后损失 | — |
| 冰面止滑 | 冰面 COF 越高越好，行业整体偏低 | 冰面斜台或拖拽实测 | 雪地摔伤投诉 | 降低温模量 + 细密刀槽 | — |
| 硬度 | 本体 60–80 Shore A 量级 | GB/T 531.1 / ISO 868 | 太硬不贴地、太软塌形 | 硬段软段配比 | 成核剂（结晶与尺寸） |
| 低温耐折 | -20℃ 下按次数考核 | GB/T 3903.1 整鞋耐折 | 低温开裂、折痕发白 | 选长碳链或聚醚软段 | 抗氧剂（热氧防护） |
| 与中底剥离强度 | 按整鞋要求定 | 剥离强度实测 | 大底开胶 | 清掉脱模剂残留 | 润滑剂（用量与迁移） |
| 耐黄变 | 浅色 / 透明件的色差限值 | 紫外老化 + 色差仪 | 浅色底发黄 | 选耐黄变基材 | 抗氧剂（含耐黄变） |
怎么用这张表：不要逐行打分。
先看"低温耐折"那一行，再看"冰面止滑"那一行。
这两行过不去，后面的磨耗数据没有意义——因为鞋会在冬天开裂，而不是慢慢磨掉。
表里"验证方法"一列，有些项目没有对应的国标，冰面止滑尤其如此。没有标准可依时，把验证方案写进技术协议，而不是省掉这一项。
表的最后一列是给做配方的人看的：同一个指标底下，扛着它的往往是不同的助剂类别。
知道哪一类在扛哪个指标，调起来才不瞎。
五、四条常见失效，和它们真正的根因
失效一：大底侧面发白，摸上去有一层粉。
第一反应通常是"这料不耐磨"。实际更常见的，是外润滑类助剂加多了，或者加工温度越过了助剂的耐温上限，它跑到表面来了。
看到发白先别换料。先查润滑剂用量和料温，再看粉霜有没有连带影响大底与中底的粘接。
失效二：夏天卖得好，冬天投诉集中。
根因是低温模量。同一款料在 20℃ 和 -20℃ 是两种手感，配方里低温那一段没做够。
这里有一条完整的时间线，值得说一遍。
一家做雪地靴的客户，起点是好的——换了更轻的底，单只鞋减重到手就能感觉出来。
中间的潜伏期很长：夏天铺货，商场里的试穿反馈全是"轻、软、舒服"，测试做的是常温止滑，全部合格。
爆发是在入冬第三周：北方几个城市集中反馈"上冻以后鞋底发滑，穿两个月侧面全是白印"。
追溯回来才发现，当时测的止滑是常温、干态、平整地面，三个条件全是暖和天气里的条件。
结算也很直接：那一季的售后成本，比换料省下的那笔账高出好几倍。
失效三：浅色底穿三个月发黄。
不全是光稳定的问题。要分清表面黄还是整体黄。
表面黄多半是光氧老化，整体黄要看基材本身的耐黄变底子，以及抗氧剂在混料阶段有没有散开。
失效四：同一批底片硬度忽高忽低。
这多半不是"料不稳定"，是结晶度不一致——模温或者冷却时间在批次之间飘了，结晶就不一致，硬度自然散。
硬度在大底上不是一个独立指标，它和结晶度本来就是一回事。
一句直说的：大底失效的排查顺序是——先分"滑"还是"磨"，再分"常温"还是"低温"，最后才去看牌号。
这三步分不清，换几次料都找不到点。
六、加工与验证：大底上有几件事必须提前定
干燥。 尼龙弹性体含酰胺段，吸湿是必然的。
料在包装里受潮、车间湿度高、回用料掺入，都会把水分带进去。干燥窗口要按实测含水率定，不能照抄推荐值。
收缩与模具。 大底是厚薄变化极大的异形件，前掌薄、后跟厚，各处收缩不一样。
模具补偿要按件做，不能套材料手册上的通用收缩率。
双色与包胶。 现在的大底越来越多是双硬度结构：外层硬一点扛磨，内层软一点贴地。
这就带来一个界面问题——两次注塑之间能不能粘住。
粘不住的原因，九成不在压力，在第一次注塑留下的脱模剂和助剂迁移层。
清洁工序比调参数有用。 这一条在大底上尤其灵。
调湿。 成型后的件会继续吸湿，尺寸和硬度都会变。
调湿要在贴合之前完成。贴合好再涨，整鞋的尺寸就跟着走。
验证顺序。 建议这样排，顺序不要换：
1. 材料级：DIN 磨耗、硬度、低温拉伸
2. 样片级：干、湿、冰三种止滑对比
3. 成品级：整只底的尺寸、花纹深度、剥离强度
4. 整鞋级：耐折（含低温）、整鞋止滑
5. 环境叠加：低温 + 融雪盐 + 紫外
前一项不过就往下走，后面的数据没有解释意义。
这里有个内行细节：底片在出炉后 24 小时测一次硬度，调湿完成后再测一次。
两次的差比绝对值更有用——差值大，说明这个件对状态敏感，整鞋厂的仓储湿度就得写进协议。
七、边界：什么时候这事不该谈
这一段可能比前面六段更值钱。
以下四种情况，这个件走尼龙弹性体大底不建议推进。
其一，纯低价通勤款、大底成本卡得很死的鞋。
尼龙弹性体的单价是普通橡胶的几倍。用在大底上，只有定位撑得住才回得来。
其二，需要极高支撑或极强耐磨的结构底、工作鞋底。
这类件的判据是寿命和支撑，硬度和结晶度的上限决定了橡胶或聚氨酯路线更合适。
其三，长期在 60℃ 以上环境里用的特殊防护鞋底。
尼龙弹性体的软段在长期高温下会软化，公开资料里这个区间的长期数据支撑不足。
其四，没有双色注塑或包胶工艺能力的产线。
大底不是换个料就能上。界面工艺跟不上，好料也做不出好底。
还有一条要单独说：鞋底片和整只大底不是一件事。
鞋底片常常是薄片、拼贴结构，判据里"尺寸稳定"的权重比整只底高一档；整只底更看重花纹成型和包胶界面。
这两件不能打包在一起做决定。
把这几条写在前面，不是劝退，是省时间。
样品阶段顺、量产阶段卡的项目，回退的成本比一开始就不做高得多。
换料风险清单（从橡胶大底换到尼龙弹性体大底，要动的东西）
| 环节 | 要动什么 | 容易漏的点 |
|---|
| 模具 | 收缩率差异大，基本要重开或大改 | 沿用橡胶模的收缩经验值 |
| 干燥 | 按实测含水率定窗口 | 沿用橡胶不用烘的车间习惯 |
| 料温 / 模温 | 窗口比橡胶窄，要重新定 | 只照供应商推荐值给 |
| 包胶与粘接 | 清洁工序与界面处理要重做 | 第一次注塑的脱模剂残留 |
| 调湿 | 贴合前完成调湿并复测尺寸 | 按平均壁厚估时间，厚处没吸透 |
| 花纹与排气 | 薄壁深花纹的排气要重排 | 沿用原花纹深度，出现缺料 |
| 色差 | 体系不同，色板要重新确认 | 浅色和透明件的黄变标准没另定 |
| 验证顺序 | 材料 → 样片 → 成品 → 整鞋 → 环境叠加 | 只做静态测试就上量产 |
一页纸汇报表（给要向上汇报的人）
| 场景 | 推荐路线 | 关键指标 | 验证标准 | 需先确认的条件 |
|---|
| 通勤休闲，常温为主 | 尼龙弹性体 + 硬质底片 | DIN 磨耗、干湿止滑 | GB/T 3903.6 | 定位能否承载成本 |
| 雪地冰面，冬季为主 | 长碳链尼龙弹性体 | 冰面止滑、-20℃ 耐折 | 冰面实测 + GB/T 3903.1 | 最低使用温度 |
| 越野跑，磨耗优先 | 橡胶或 TPU 为主 | 磨耗、撕裂强度 | GB/T 9867 | 是否必须减重 |
| 轻量款，减重优先 | 薄底 + 硬质外片 | 密度、剥离强度 | 剥离强度实测 | 双色注塑能力 |
风险提示：本路线的主要不确定性在低温止滑和包胶界面，不在常温磨耗。
读者常问的三句
问：冰面止滑能不能靠配方解决？
能改善，但不能只看配方。冰面摩擦靠的是软硬度和花纹配合，细密刀槽带来的边际收益，有时比换料更大。顺序是先定花纹和硬度，再定料。
问：DIN 磨耗的数越小越好吗？
在这个指标上是。但它和止滑、硬度是一组联动值。单独把磨耗压得很低，往往意味着配方整体变硬，冰面止滑跟着掉。三个数要一起看。
问：尼龙弹性体大底能不能回收？
比含硫橡胶好处理，但仍要看整鞋结构是不是多材质拼接。这两年整鞋设计在往少材质、可拆解走，这一条要在出图阶段就定下来。
结语
回到开头那个客户。
我最后回了他三句话：先分湿滑还是冰滑，再定最低使用温度，最后才谈 DIN 磨耗。
因为这三个问题的答案不同，落到料上就是三条不同的路。
大底料的判断链，说到底只有三条：
地面与温度定软硬 → 花纹定止滑 → 结构定界面。
如果手上正有一个大底或者鞋底片要定料，把三样东西发过来就能给方向：目标鞋型、最低使用温度、目标里程。
这里做塑料的人多，做鞋材的却不多——很多答案其实写在消费者的里程表上，不写在物性表上。
我们做的事很具体：把 PA6、PA66、PA46、PA11、PA12、PA6T、PA9T 和尼龙合金这些树脂，改成某个件真正能用的样子；顺带做改性 PPO、PPS 和热塑性弹性体。
也经营各大化工巨头的尼龙树脂、副牌料和大包料。另：长期收尼龙原料、水口回料与各类尼龙废料，有正规处置渠道。
配方里的助剂体系按件的工况配——常规助剂常备现货，特殊型号按需配套；你报工况和牌号，料和助剂一次配齐。
这类件的选料与试模，可以一起聊。
Last month, a customer who makes hiking shoes came to ask what material should be used for the shoe sole.
He wants to replace a rubber sole with an elastomer based on a modified nylon system, for only one reason: weight reduction.
When sending the sample, he attached a note, on which three numbers were written in ballpoint pen: DIN wear 120, wet slip 0.42, hardness 62.
On the phone he spoke very directly: 'I only want these three numbers, nothing else.'
I asked him the first question: Who gave you these three numbers? He paused for two seconds and said, the previous material factory.
I said: These three numbers are not three numbers in the same dimension; they are two accounts undermining each other.
This article explains three things about outsoles: why wear resistance and slip resistance are in conflict, what each of the three routes sacrifices, and what kind of shoes really shouldn’t modify the outsole.
1. The failure of the outsole is, in 80% of cases, not 'worn through,' but 'slipped first.'
First, clarify the work done by the base sole.
The sole is divided into three layers: the midsole provides cushioning and rebound, the outsole provides grip and wear resistance, and the sole plate is the piece sandwiched in the middle or directly attached to the ground.
The outsole needs to do four things at the same time: grip the ground, withstand wear, support the foot, and maintain its shape.
Out of the four things, consumers will only complain about two: wearing out quickly and being too slippery.
And these two, in terms of materials, are a pair of inverse variables.
Why reverse—anti-slip relies on 'stick'.
The softer the material, the deeper the microscopic protrusions embed into the ground when stepped on, the larger the real contact area, and the greater the friction.
Wear-resistant relies on 'bearing'.
The harder the material and the higher the crystallinity, the less material is cut away by the ground.
One needs to be soft, the other needs to be hard. This is the primary contradiction of the base seasoning.
In one sentence: The selection of the outsole, in essence, is about finding a position between 'sticking well' and 'bearing well'.
And this position is not fixed; it moves with the temperature.
Rubber is soft at normal temperature and provides good slip resistance on wet surfaces; when it reaches below minus ten degrees, it becomes hard and brittle, losing both slip resistance and folding durability.
The modulus change of nylon elastomer in this section is smoother than that of rubber, and low temperature is its opportunity.
But the hardness and wear resistance limit at room temperature is not as flexible as rubber.
So the real question shouldn't be 'which material is better'.
The question should be: On what temperature of ground are these shoes mainly used for running?
Let's go back to that note at the beginning.
That client wrote the DIN wear, slip coefficient, and hardness all in one line, treating it as an inspection sheet.
The problem is that the sources of these three numbers are completely different: wear is the volume loss on the test bench, slip resistance is the coefficient of friction, and hardness is the indentation.
They are three separate curves, and in most formulas, when one goes up, another has to go down.
How these three curves are arranged is really what needs to be discussed when choosing the main seasoning base.
2. Six-dimensional working condition: What exactly is pinching the big base
Break down the operating conditions of the main base into six dimensions, and assign a verifiable quantity to each dimension.
Temperature. This is the first dimension, and also the dimension that is most easily overlooked.
Commuter shoes in southern cities may be worn in temperatures as low as 0°C; for outdoor activities in northern winters, -20°C is normal, and -30°C also needs to be taken into consideration.
Temperature determines two things: the modulus of the material, and the material's bending lifespan.
Load and wear. A person weighing 70 kilograms, when walking normally, bears a weight of 1 to 1.5 times their body weight on a single foot; the peak load when running can reach 3 times the body weight.
To convert it: when a 70-kilogram person runs, the forefoot of the sole has to absorb a force of around 200 kilograms at the moment of landing.
This force doesn't happen just once; it comes every time you land.
The quantitative indicator of wear is DIN wear, measured in cubic millimeters—the smaller the value, the more wear-resistant it is.
Medium. Water, snow, ice, melting salt, oil stains, detergent, all of these need to be gone through.
Ice is a special case; it is not solid friction, but lubrication on the 'surface layer of water'.
Why does this happen — the friction on the ice surface generates heat, which melts a layer of water at the micron level, and the material is actually sliding on water.
So being 'hard' on the ice is not an advantage at all.
What really works are hysteresis loss and the real contact area, that is, the part of the energy loss when the material is compressed and then springs back.
Lifespan. A pair of commuting shoes is calculated at 800 kilometers, and a pair of trail shoes is calculated at 500 kilometers.
800 kilometers is approximately 1 million to 1.3 million steps.
Every step is a bend, a cut, and only when accumulated do they become the true measure of assessment.
Appearance. For light-colored and transparent outsoles, we look at yellowing and haze. This is a strict criterion for outsoles because the entire piece is exposed.
Compliance and environmental protection. Contact with the ground and skin involves consumer product safety and volatile substances; in the past two years, there has also been an additional focus on recyclability and single-material direction.
When the six dimensions are placed together, one can see a conclusion: these six dimensions are not parallel; they are sequential.
When the temperature changes, the modulus changes; when the modulus changes, the slip resistance changes; if the slip resistance needs to be improved, the hardness must decrease; when the hardness decreases, the wear increases.
They are a chain; when one link moves, the rest follow.
3. Three routes side by side: each one's strengths and the tuition to be paid
| Route | Anti-slip (Dry / Wet / Ice) | Wear-resistant | Low-temperature fold resistance | Density | Combined with the midsole | Common positioning |
|---|
| Vulcanized Rubber (NR / SBR / BR) | Good / Good / Medium | middle | Hardened at medium and low temperatures | tall | Interface processing required | Main support level |
| TPU system | Good / Medium / Medium | Good | middle | middle | Can be directly overmolded | Sports and leisure |
| Nylon Thermoplastic Elastomer (TPAE / PEBA) | Medium / Good / Good | Adjustable formula | Good | Low | Can be directly overmolded | Lightweight, ice surface, high-rebound sole |
Look at this table. The key is not which column is the strongest, but that you have to pay the tuition in every column.
The tuition of rubber is weight and low temperature.
For the same pair of size 42 shoes, the rubber outsole usually weighs several dozen grams more than the nylon elastomer outsole. Those several dozen grams are the difference between a 'lightweight version' and a 'regular version' for the whole shoe.
TPU's tuition is low temperature.
At room temperature, it is almost omnipotent, but below -20°C, the modulus rises quickly, and both anti-slip and fold resistance decrease together.
The tuition of nylon elastomer is wear resistance and cost.
Its hard segments are polyamide, and the crystallinity provides an abrasion-resistant base; but the polyether soft segments in the molecular chain are inherently soft to adhere to the ice surface.
The wear-resistant line needs to go up, and there are usually only two paths.
One approach is to increase the proportion of hard segments, with the trade-off being a decline in low-temperature performance.
The other approach is to rely on a modified system to make up for it, but the cost is that you have to be careful with the appearance and interface.
Here is one that is easy to overlook: Nylon elastomer is not a 'stronger EVA,' nor is it a 'lighter rubber.'
It is a different system—processing windows, molds, and recycling paths are all different.
Using rubber molds and processes directly on nylon elastomers will most likely get stuck at the shrinkage and adhesion stages.
So when it comes to changing materials, what truly needs to be evaluated is never 'whether the material is good enough,' but 'which row this pair of shoes is willing to give way to.'
4. Selection Criteria Table (It is recommended to save this page)
Threshold values are directional recommendations, not acceptance criteria. The actual values must be determined through actual measurements based on shoe model, shoe size, target market, and usage temperature.
| Indicator | Directional Threshold | Verification Method / Standard | Common Failures | Common solution | Corresponding auxiliary system |
|---|
| DIN wear | Set according to positioning; for commuting, it is recommended to stay within 150 mm³ | GB/T 9867 / ISO 4649 | Base pattern smoothed, midsole exposed by grinding | Increase the proportion of hard segments or modify the system | Wear-resistant packing (depending on the system) |
| Dry anti-slip | Flat steel plate COF starting at the 0.7 level | GB/T 3903.6 Whole Shoe Slip Resistance | Wheel spin during ground start | Enhance soft section flexibility Pattern | — |
| Wet anti-slip | COF above 0.4 under water film conditions | Same as above, with soapy solution conditions | Slippery tile surface on rainy days | Increase lag loss | — |
| Ice surface anti-slip | The higher the ice surface COF, the better; the industry overall tends to be low. | Ice surface inclined platform or drag test | Complaint about injury from falling in the snow | Reduce thermal modulus Fine grooves | — |
| Hardness | Body 60–80 Shore A range | GB/T 531.1 / ISO 868 | Too hard and not close to the ground, too soft and collapsing | Hard section and soft section ratio | Nucleating Agent (Crystallization and Size) |
| Low-temperature fold resistance | Assessment based on the number of times at -20℃ | GB/T 3903.1 Whole Shoe Flexing Resistance | Low-temperature cracking and whitening of creases | Choose long carbon chains or polyether soft segments | Antioxidant (Thermal Oxidation Protection) |
| Delamination strength with the midsole | Made according to whole shoe requirements | Measured peeling strength | Outsole detachment | Remove mold release residue | Lubricant (Usage and Migration) |
| Yellowing resistance | Color difference limits for light-colored/transparent parts | UV Aging Colorimeter | Light-colored base turning yellow | Choose a substrate resistant to yellowing | Antioxidant (including anti-yellowing) |
How to use this table: Do not score line by line.
First look at the line 'low temperature bend resistance,' then look at the line 'ice surface anti-slip.'
These two lines don't make sense, the subsequent wear data is meaningless—because the shoes will crack in winter, rather than wear down slowly.
In the 'Internal and External' verification method column, some items do not have corresponding national standards, especially ice surface slip resistance. When there is no standard to follow, include the verification plan in the technical agreement instead of omitting this item.
The last column of the table is intended for the person making the formula: under the same indicator, it is often supported by different types of additives.
Knowing which category is responsible for which metric makes adjustments not random.
Five, four common failures and their real root causes
Failure 1: The side of the outsole turns white, and when touched, there is a layer of powder.
The first reaction is usually 'this material is not wear-resistant.' In reality, what is more common is that an external lubricant additive has been added too much, or the processing temperature has exceeded the additive's thermal limit, causing it to come to the surface.
If you see whitening, don't change the material immediately. First, check the amount of lubricant and the material temperature, then see if the powder coating has any impact on the bonding between the outsole and midsole.
Failure 2: Sells well in summer, complaints concentrate in winter.
The root cause is low-temperature modulus. The same material feels different at 20°C and -20°C; the low-temperature part in the formula was not done enough.
Here is a complete timeline, worth mentioning again.
A client making snow boots started off well—after switching to a lighter sole, the weight reduction of a single shoe can be felt immediately when held.
The incubation period in the middle is very long: they stock up in summer, and the fitting feedback in the mall is all 'light, soft, comfortable.' The tests are done at normal temperature for slip resistance, and all pass.
The outbreak occurred in the third week of winter: several northern cities reported that after freezing, shoe soles became slippery, and after wearing for two months, the sides were all covered with white marks.
Looking back, I realized that the slip resistance was tested under room temperature, dry conditions, and on a flat surface, all three of which are conditions found in warm weather.
The settlement is also very straightforward: the after-sales costs for that season were several times higher than the amount saved by changing the materials.
Failure 3: Light-colored base turns yellow after three months of wear.
It's not entirely a matter of light stability. You need to distinguish whether it's the surface yellowing or overall yellowing.
Surface yellowing is mostly due to photo-oxidative aging, while overall yellowing depends on the inherent yellowing resistance of the base material and whether the antioxidant has dispersed during the mixing stage.
Failure Four: The hardness of the same batch of film varies from high to low.
This is probably not due to 'unstable material,' but inconsistent crystallinity — if the mold temperature or cooling time varies between batches, the crystallinity will be inconsistent, and hardness will naturally vary.
Hardness on the outsole is not an independent metric; it is essentially the same as the degree of crystallinity.
To put it bluntly: the troubleshooting order for outsole failure is—first determine whether it is 'slipping' or 'abrasion', then distinguish between 'normal temperature' and 'low temperature', and only finally look at the grade.
If you can't distinguish these three steps, no matter how many times you change the material, you still can't find the point.
6. Processing and Verification: There are several things that must be decided in advance regarding the outsole.
Dry. Nylon elastomers contain amide segments, so moisture absorption is inevitable.
Moisture can get in if the material is damp in the packaging, the workshop humidity is high, or recycled material is mixed in. The drying window should be set according to the actual measured moisture content, not just copied from the recommended values.
Shrinkage and molds. The outsole is an irregularly shaped part with varying thickness, thin at the forefoot and thick at the heel, with different shrinkage in each area.
Mold compensation must be done per piece and cannot use the general shrinkage rate from the material manual.
Two-tone and encapsulated rubber. Nowadays, more and more outsoles are made with a dual hardness structure: the outer layer is harder for abrasion resistance, and the inner layer is softer for better ground grip.
This brings up an interface issue—whether the two injections can stick together.
The reason it doesn't stick is ninety percent not due to pressure, but due to the release agent and additive migration layer left from the first injection molding.
Cleaning procedures are more useful than adjusting parameters. This is especially effective on the outsole.
Moisture conditioning. The molded parts will continue to absorb moisture, and their dimensions and hardness will change.
Moisture adjustment should be completed before fitting. If it expands after fitting, the size of the whole shoe will change accordingly.
Verification order. It is recommended to arrange it like this, do not change the order:
1. Material level: DIN abrasion, hardness, low-temperature tensile
2. Sample level: Comparison of anti-slip performance for dry, wet, and icy conditions
3. Finished Product Grade: Whole sole size, pattern depth, peeling strength
4. Whole shoe level: fold resistance (including low temperature), whole shoe slip resistance
5. Environmental Superposition: Low Temperature Road Salt Ultraviolet
The previous item just goes downward, and the following data has no explanatory significance.
Here's an insider detail: After the film is developed, measure its hardness every 24 hours, and measure it again after humidity adjustment is completed.
The difference between the two is more useful than the absolute value—if the difference is large, it indicates that this part is sensitive to conditions, and the storage humidity of the entire shoe factory must be included in the agreement.
7. Boundaries: When This Matter Should Not Be Discussed
This section might be more valuable than the previous six sections.
In the following four situations, it is not recommended to proceed with this item using a nylon elastomer sole.
First, shoes that are purely low-priced commuter models, with outsole costs tightly controlled.
The unit price of nylon elastomer is several times that of ordinary rubber. When used on outsoles, it will only return if the positioning can hold.
Secondly, it requires structural soles or work shoe soles with extremely high support or extremely strong wear resistance.
The criteria for this type of component are lifespan and support, with the upper limits of hardness and crystallinity determining whether a rubber or polyurethane route is more suitable.
Third, special protective shoe soles used for long periods in environments above 60°C.
The soft segments of nylon elastomers will soften under long-term high temperatures, and there is insufficient long-term data support for this range in publicly available information.
Fourth, production lines without the capability for two-color injection molding or over-molding processes.
The outsole can't be improved just by changing the material. If the interface craftsmanship isn't up to par, even good materials can't produce a good sole.
There is one more point that needs to be mentioned separately: the sole piece and the entire outsole are not the same thing.
Shoe sole pieces are often thin sheets or patchwork structures, with the criterion 'dimensional stability' weighted higher than for an entire sole; the whole sole focuses more on the pattern molding and the bonding interface with the rubber.
These two things cannot be decided on together.
Writing these few points at the beginning is not to discourage, but to save time.
For projects that go smoothly in the sample phase but get stuck in the mass production phase, the cost of reverting is much higher than not doing it from the beginning.
Material Change Risk List (Things that need to be changed when switching from rubber outsoles to nylon elastomer outsoles)
| link; segment; part | What do you want to move? | Points that are easy to overlook |
|---|
| Mold | The shrinkage rate varies greatly, basically requiring a restart or major changes. | Continue using the shrinkage empirical value of the rubber mold |
| Dry | Set the window according to the measured moisture content | Continue the workshop practice of using rubber without baking |
| Material Temperature / Mold Temperature | The window is narrower than the rubber, it needs to be reordered. | Only give according to the supplier's recommended value |
| Overmolding and Bonding | The cleaning process and interface treatment need to be redone | Residual mold release agent from the first injection molding |
| Humidity control | Complete humidity adjustment and re-measure dimensions before bonding | Estimating time based on average wall thickness, the thicker part hasn't absorbed fully. |
| Pattern and exhaust | Thin-walled deep-pattern exhaust needs to be rearranged | Using the original pattern depth, material shortage occurs |
| Color difference | The system is different, the color palette needs to be reconfirmed | No separate yellowing standard is set for light-colored and transparent parts |
| Verification order | Materials → Sample → Finished Product → Complete Shoe → Environmental Overlay | Going straight to mass production after only doing static testing |
One-page report sheet (for people who need to report upwards)
| Scene | Recommended Route | Key indicators | Verification standard | Conditions that need to be confirmed first |
|---|
| Commuting and casual, mainly at normal temperature | Nylon elastomer Rigid film | DIN wear resistance, dry and wet anti-slip | GB/T 3903.6 | Can positioning bear the cost? |
| Snowy and icy surfaces, mainly in winter | Long-chain nylon elastomer | Non-slip on ice, -20°C fold-resistant | Ice Surface Field Measurement GB/T 3903.1 | Minimum operating temperature |
| Trail running, wear resistance first | Primarily made of rubber or TPU | Wear and tear strength, tear resistance | GB/T 9867 | Is it necessary to lose weight? |
| Lightweight version, weight reduction prioritized | Thin sole, hard outer piece | Density, peel strength | Measured peeling strength | Two-color injection molding capability |
Risk Warning: The main uncertainties of this route lie in low-temperature skid resistance and the rubber bonding interface, not in normal temperature wear.
Three questions readers often ask
Question: Can ice surface anti-slip be solved with a formula?
It can improve, but you can't just look at the formula. Ice surface friction relies on the combination of hardness and pattern; the marginal benefit brought by fine blade grooves is sometimes greater than changing the material. The order is to first determine the pattern and hardness, and then decide on the material.
Question: Is it better if the DIN wear number is smaller?
On this metric, yes. But it is a set of linked values with slip resistance and hardness. Lowering wear alone often means the overall formula becomes harder, and slip resistance on ice decreases accordingly. All three numbers need to be considered together.
Question: Can nylon elastomer outsoles be recycled?
is easier to handle than sulfur-containing rubber, but it still depends on whether the overall shoe structure is multi-material splicing. In recent years, whole shoe designs have been moving toward fewer materials and disassemblable designs. This needs to be determined at the drawing stage.
Conclusion
Returning to the client mentioned at the beginning.
I finally replied to him with three sentences: first, distinguish between slippery and icy surfaces; then determine the minimum usage temperature; and finally, discuss DIN abrasion.
Because the answers to these three questions differ, it leads to three different paths in material selection.
The judgment chain for outsole materials, ultimately, has only three steps:
Determine hardness/softness by ground and temperature → Determine anti-slip pattern → Determine interface by structure.
If you currently have an outsole or midsole piece that needs material selection, you can send these three things to get guidance: target shoe type, minimum usage temperature, and target mileage.
Many people here work with plastics, but fewer work with shoe materials — many answers are actually in the consumer’s mileage chart, not in the physical property table.
What we do is very specific: we take resins like PA6, PA66, PA46, PA11, PA12, PA6T, PA9T, and nylon alloys, and turn them into something that can actually be used in a part; we also modify PPO, PPS, and thermoplastic elastomers.
We also handle nylon resins, secondary brand materials, and bulk materials from major chemical giants. Additionally, we long-term acquire nylon raw materials, sprue scrap, and various nylon waste, with proper disposal channels.
The additive system in the formulation is matched according to the part’s working conditions — common additives are kept in stock, special models are customized as needed; you provide the working conditions and grade, and the materials and additives are provided together.
Material selection and mold trial for such parts can be discussed together.
