236 改性尼龙按温度选型索引
开篇先讲个现场
去年给一家做厨房小电器的客户定料，对方研发拿着红外测温枪对着一台样机测了一圈，报了个数：机壳内部实测 95 度，选 PA6 加玻纤肯定没问题。结果样机跑到第三个月， 客户反馈支架变形了。
拉回来一查，变形位置贴着发热盘，那一点的局部温度远不止 95 度——红外枪测的是表面，内部热源附近的料温比表面高出一大截。
这个案例后来在我们内部讨论过好几次，因为它暴露了一个特别常见的误区：温度选型不是查一个数、对一个表就完事，测温这个动作本身就有讲究。测哪一点、什么时候测、连续测还是瞬时测、停机后再测还是运行中测，每一个选择都会让数字漂移十几度，而选型档位可能就卡在十几度上。
这篇索引把常用温度区间切成五档，从 80 度以下一直排到 180 度以上，每一档给出对应的基材和改性体系建议、这一档的典型场景、以及最容易被忽略的坑。索引之外，还专门写了温度测量的注意事项和降一档的思路——后者是很多老研发的看家本领：与其硬上高一档的料，不如把导热路径重新布置一下，让料在低一档里舒服干活，成本能省下一大截。
用这份索引之前，请先确认一件事：你手里的温度数，是实测的、连续的、代表最恶劣工况的数。如果不是，先补测，再翻表。
第一档：80℃ 以下
适用材料：PA6 通用牌号、PP-GF30、PA66 通用牌号。判断要点：这一档是最宽松的，几乎所有尼龙都能用，选材主要考虑强度、韧性、成本而不是耐热。
如果温度确定在 80℃ 以下，PA6 是性价比最优的选择。注意：短时峰值温度不算，看的是长期工作温度。
第二档：80-120℃
适用材料：PA66（主力）、PA66-GF30、PA6 耐热牌号。判断要点：这一档 PA6 开始吃力，PA66 成为主力。必须加抗氧剂 + 热稳定剂——PA66 在 120℃ 长期不加耐热体系，2000 h 强度掉一半。
另外要考虑蠕变——长期受力件必须玻纤增强。这是汽车机舱外围、家电电机周边的典型温度。
第三档：120-150℃
适用材料：PA66 耐热牌号、PA46、PBT-GF30、PA6T 共聚。判断要点：PA66 已经到极限，要用专用耐热牌号或升级基材。
这一档的分岔点在湿度——干燥环境用 PA46 或 PA66 耐热牌号；潮湿环境要用低吸水的高温尼龙。典型应用：发动机周边、SMT 连接器、LED 支架。
第四档：150-180℃
适用材料：高温尼龙（PA6T、PA9T、PA10T）、PPS。判断要点：这一档是高温尼龙的主场。选择逻辑：干燥高温选 PA46 或 PA6T；
潮湿高温选 PA9T 或 PA10T（低吸水）；有化学腐蚀选 PPS。加工门槛明显提高——料筒 300-340℃、模温 120-150℃、含水率 < 0.05%。没有相应设备就做不了。
一次翻车的测温复盘
上面开篇讲的厨房电器案例，值得把复盘写全。那个项目最后是怎么救回来的？分了三步。第一步重测：不用红外枪，改用埋入式热电偶，直接贴在支架的安装孔位置，运行二十四小时连续记录，测出来的峰值温度比表面测温高出三十七度。
第二步归因：高温来源不是环境，是发热盘通过紧固螺丝的热传导，热路径很清楚。第三步重选：温度档位从二档跳到四档，同时客户把导热路径改了一下，加了一片隔热垫，让料回到三档区间工作。最终用的是热稳定增强 PA66，比一开始硬上高温体系的方案省了两成的材料成本。
这个复盘里最值钱的一句是：测温的误差来源往往不是仪器，是位置和时机。表面和内部、瞬时和连续、满载和空载，每个选择都能差出几十度。温度索引是静态的表，测温是动态的活，表用得对不对，全看数是怎么来的。
第五档：180℃ 以上
适用材料：PPS（200℃）、PEI（170-200℃）、PEEK（250℃）、LCP、PI。判断要点：这一档已经超出尼龙的能力范围（除极少数特种牌号）。
价格呈指数上升：PPS 是 PA66 的 2-3 倍，PEI 是 8-15 倍，PEEK 是 20-30 倍。选材原则是选刚好够用的那一档，不要过度设计。
温度之外还要看时间
温度索引用熟之后，会自然遇到下一个维度：时间。80 度用一年和 80 度用八年，对材料的要求不是一回事，蠕变和热氧老化都是时间的函数。我们内部把温度和时间放在一起做二维判断：短时高温看热变形温度，长时高温看热老化后的性能保持率，两个数经常来自完全不同的测试。
如果一个应用长年在三档温度下服役，别只对照三档的推荐表，还要追问一句预期寿命几年——寿命超过五年的，建议整体上移半档选料，给老化留出余量。这一句余量，是速查表教不了、只能写在这里的经验。
温度测量的注意事项
很多温度判断错误源于测不准：一是要测实际工况温度，不是环境温度——密闭机箱内比环境高 20-40℃；二是要区分长期和峰值——短时峰值不影响选材，长期温度才影响；
三是要注意热叠加——自身发热 + 环境温度的叠加。建议在样机阶段实测温度，用热电偶或测温贴片记录完整周期。
降一档的思路
如果材料成本因温度档上升太多，可以考虑降低实际工作温度：加隔热或遮阳——户外设备最有效；改善散热——通风、散热筋、导热填料；远离热源——调整布局或加挡板。
这三招往往比换更贵的材料划算——降 10℃ 可能省下一档材料成本。
工程实测：4 条强制测试
测试1：PA66 长期。120-140℃，超过要用耐热牌号或升级基材。
测试2：临界点。80℃ 是 PA6/PA66 的分界，150℃ 是 PA/高温尼龙的分界。
测试3：温升叠加。密闭机箱内比环境高 20-40℃——必须实测。
测试4：成本档位。PPS 2-3 倍，PEI 8-15 倍，PEEK 20-30 倍（相对 PA66）。
边界声明
| 工况 | 推荐材料 |
|---|
| < 80℃ | PA6 通用，成本优先 |
| 80-120℃ | PA66 + 抗氧耐热体系 |
| 120-150℃ | PA46 或 PA6T（干燥）/ 低吸水高温尼龙（潮湿） |
| 150-180℃ | PA9T / PA10T / PPS |
| > 180℃ | PPS / PEI / PEEK |
工程备忘
温度四档：80℃ 是 PA6 与 PA66 的分界，150℃ 是 PA 与高温尼龙的分界。实测温度比估算可靠，降 10℃ 可能省一档材料。
实战案例：常见踩坑与正解
踩坑一：按温度选材查到了结论但没查适用条件，直接套用出错。任何速查表都有前提，脱离前提的结论都是错的。正解：看到结论先找它成立的条件——温度、介质、时间、载荷类型，四项齐全才敢用。
踩坑二：照抄别人的选型，没考虑自己的工艺能力。同样的料，不同设备和模具打出来效果不同。正解：选型要结合自己的工艺水平，不要选超出设备能力的材料。踩坑三：把速查表当最终依据，不做实际验证。正解：速查表用来缩小范围，最终一定要打样验证。
延伸判断：选型前要先确认的三件事
按温度选材在选料之前，有三件事要先问清楚，顺序错了后面全部返工。
第一：长期使用温度是多少。短时峰值温度和长期工作温度是两回事，物性表上的热变形温度是短时指标，长期工作温度一般要打七折看。
第二：接触什么介质。油、水、清洗剂、汗液、电解液，每一种都会改变料号选择，介质清单比温度表更重要。
第三：有没有认证要求。阻燃、CTI、食品接触、涉水卫生、安规认证，有认证要求的件，换料号就要重新验证，代价远高于材料差价的几十块钱。这三件事问清楚，选料就完成了一半。
把这三件事写成一张表发给供应商，比打十通电话有用——按温度选材的选型沟通成本，基本都花在这几项反复确认上。
温度问答四则
问：产品标注耐温一百二十度，是说可以长期用吗？ 多数不是。标注的多半是热变形温度或短期峰值，长期使用温度要单独问老化数据。拿峰值当长期值选料，是温度问题里最经典的翻车姿势。
问：环境温度和料温怎么换算？ 没有固定换算，只有实测。发热件内部、贴热源的局部、阳光直晒面，料温和环境温度的差可以从几度到上百度。红外枪加热电偶双测，是成本最低的稳妥组合。
问：间歇高温和持续高温，选料一样吗？ 不一样。间歇高温主要看短时耐热和热变形，持续高温要看热老化寿命，后者严苛得多。问工况时这两个词要分清，答案可能差出一个材料档位。
问：温度档位临界时怎么定？ 上移半档，或者改结构降温。两个方案都比在临界点上赌强。临界选料省下的钱，往往不够赔一次批量失效。
测温四件套
把测温这件事工具化，配齐四件套。第一件：热电偶加巡检仪，测内部和贴壁温度，这是主力数据。第二件：红外热像仪，整机扫一遍找热点，确定热电偶该贴在哪。第三件：表面温度贴，贴在关键部位随件运行，事后读峰值，适合量产阶段的持续监控。
第四件：记录表，点位、时间、工况状态三栏，测完当天归档。四件套配齐成本不高，换来的是温度数据从玄学变成台账。我们给客户做温度诊断，用的就是这一套组合，第一次测完，多数客户都会发现至少一个此前不知道的热点。热点不吓人，不知道才吓人。
高温件的设计侧减负
温度选型除了换更好的料，还有半张牌在设计手里。常见四招：一是拉距离，把料和热源隔开，加隔热垫、开散热孔，成本几毛钱，档位能降一档；二是减壁厚，厚壁件芯部散热慢，温度比表面高，减薄等于给芯部降温；
三是错峰，让高温时段和满载受力时段错开，比如高温下解除预紧的结构设计；四是换介质，能风冷的别靠料扛。四招共同点是先动结构再动材料，动结构的钱通常比升级材料省一半以上。设计侧和材料侧各让一步，很多看似卡死的温度难题就解开了。选型索引是底线思维，设计减负是空间思维，两手都有，方案才从容。
温度档案随件走
温度数据的积累，建议做成档案随产品走：每个量产产品一页温度档案，记录开发期实测的温度分布图、关键点位、最恶劣工况，产品改版时档案跟着升级。这样做的回报在多年后显现：换供应商、换材料、改设计，新人不用重新摸一遍温度场，翻开档案就接上了。
温度是看不见的，档案让它显形并沉淀下来。这个做法成本几乎为零，需要的只是一开始多测几遍的耐心。温度选型的功夫，一半在选料那一刻，另一半在这些看不见的积累里。
温度选型还有个常见纠结：两个档位之间的料价差很大，怎么选？给个判断口诀：看温度余量和失效后果，余量小于两成或失效后果严重的，往高档选；余量充足且失效可修复的，可以留在低档并加密监控。
口诀背后是个简单的概率账，高档料价是确定的多支出，低档失效是概率性的大支出，算期望值，答案通常自己清楚。
结语
这句话我们每周都听到——选料这件事，越早问越省事。
这类件的选料与试模，可以一起聊。
236 Modified nylon selection index by temperature
Starting with a live talk
Last year, I ordered materials for a client making small kitchen appliances. The developer tested a prototype with an infrared thermometer and reported the figure: the internal temperature of the casing was 95°C, so choosing PA6 with fiberglass was definitely fine. But by the third month after the prototype had run, the customer reported that the bracket had deformed.
Pulling it back to check, the deformation spot was attached to the heating plate, and the local temperature at that point was far higher than 95°C—the infrared gun measured the surface, and the material temperature near the internal heat source was much higher than the surface.
This case was discussed internally several times later because it exposed a very common misconception: temperature selection isn't just about checking a number or a table; temperature measurement itself has its own significance. Measuring at what point, when, continuous or instantaneous measurement, after shutdown or during operation—every choice causes the numbers to drift by more than ten degrees, and the selection threshold might be stuck in the teens.
This index divides commonly used temperature ranges into five levels, from below 80 degrees down to above 180 degrees, each providing corresponding substrate and modification system recommendations, typical scenarios for this range, and the most easily overlooked pitfalls. Besides the index, it also specifically lists temperature measurement precautions and downgrade ideas—the latter is a specialty of many veteran developers: rather than forcing a higher grade, it's better to rearrange the thermal conduction path so the material can work comfortably at a lower level, saving a lot of costs.
Before using this index, please confirm one thing: the temperature value you have is a real-test, continuous number representing the harshest working conditions. If not, first retest and then check the table.
First level: below 80° C
Applicable materials: PA6 general grade, PP-GF30, PA66 general grade. Key judgment points: This grade is the most relaxed and can be used with almost all types of nylon. Material selection mainly considers strength, toughness, and cost rather than heat resistance.
If the temperature is set below 80°C, PA6 is the most cost-effective choice. Note: Short-term peak temperatures are not counted; what matters is the long-term operating temperature.
Level 2: 80-120°C
Applicable materials: PA66 (main force), PA66-GF30, PA6 heat-resistant grades. Key points for judgment: At this level, PA6 starts to struggle, and PA66 becomes the main force. Antioxidant + heat stabilizer must be added—if PA66 is not used for a long time at 120°C, its strength will be halved at 2000 hours.
Another consideration is creep—long-term load-bearing components must be reinforced with glass fiber. This is the typical temperature around the car engine compartment and around home appliance motors.
Third level: 120-150°C
Applicable materials: PA66 heat-resistant grade, PA46, PBT-GF30, PA6T copolymer. Key judgment points: PA66 has reached its limit and requires a dedicated heat-resistant grade or upgraded substrate.
The branching point for this level is humidity—use PA46 or PA66 heat-resistant grades in dry environments; Use low-absorption, high-temperature nylon for humid environments. Typical applications: engine peripherals, SMT connectors, LED brackets.
Fourth level: 150-180°C
Applicable materials: high-temperature nylon (PA6T, PA9T, PA10T), PPS. Key judgment points: This grade is the main domain for high-temperature nylon. Selection logic: For drying and high temperatures, choose PA46 or PA6T;
For humid and high temperatures, choose PA9T or PA10T (low water absorption); For chemical corrosion, choose PPS. The processing threshold is significantly higher—barrel 300-340°C, mold temperature 120-150°C, moisture content < 0.05%. Without the corresponding equipment, it cannot be done.
A Failed Temperature Measurement Review
The kitchen appliance case mentioned at the beginning above is worth writing the full review. How did that project end up being saved? It was divided into three steps. Step one: Retest: instead of an infrared gun, use a built-in thermocouple, attach it directly to the mounting hole on the bracket, and record continuously for twenty-four hours. The peak temperature measured was 37 degrees higher than the surface temperature measurement.
Step two: attribution: The source of high temperature is not the environment, but heat conduction through the heating plate and the fastening screws, so the heat path is very clear. Step three: Reselect: The temperature level jumps from level two to four, and the client changes the heat conduction path, adding a heat insulation pad to bring the material back to level three. In the end, we used thermally stable-enhanced PA66, which saved 20% of material costs compared to the initial plan for a high-temperature system.
The most valuable part of this review is: the source of temperature measurement error is often not the instrument, but the position and timing. Surface versus interior, instantaneous and continuous, full load and no-load—each choice can differ by tens of degrees. The temperature index is a static table, while temperature measurement is dynamic. Whether the meter is used correctly depends entirely on how the numbers are calculated.
Fifth level: above 180°C
Applicable materials: PPS (200°C), PEI (170-200°C), PEEK (250°C), LCP, PI. Key points: This grade is already beyond nylon's range (except for a few special grades).
Price rises exponentially: PPS is 2-3 times that of PA66, PEI is 8-15 times, PEEK is 20-30 times. The principle for selecting materials is to choose the grade that is just sufficient; do not over-design.
Besides temperature, also consider time
After using the temperature index, you will naturally encounter the next dimension: time. Using 80 degrees for one year and 80 degrees for eight years have different material requirements; creep and thermal-oxidation aging are both functions of time. We internally combine temperature and time for two-dimensional judgment: short-term high temperatures look at thermal deformation temperature, long-term high temperatures look at performance retention after thermal aging. These two values often come from completely different tests.
If an application has been operating at three temperature levels for years, don't just compare it to the recommendation table—ask about the expected lifespan—if it lasts more than five years, it's recommended to move the material selection up half a level to allow for aging. This margin is an experience that the quick reference table can't teach and can only be written here.
Precautions for temperature measurement
Many temperature misjudgments stem from inaccurate measurements: first, measure actual operating temperature, not ambient temperature—the sealed case is 20-40°C higher than the environment; Second, distinguish between long-term and peak values—short-term peaks do not affect material selection, only long-term temperature does;
Third, pay attention to heat superposition—self-heating + ambient temperature overlay. It is recommended to measure the temperature during the prototype stage and record the full cycle using thermocouples or temperature measuring chips.
Idea of lowering the temperature by one level
If material costs rise too much due to temperature ranges, consider lowering the actual operating temperature: add insulation or shading—outdoor equipment is most effective; Improve heat dissipation—ventilate, heat vents, thermal fillers; Stay away from heat sources—adjust layout or add baffles.
These three tricks are often more cost-effective than switching to more expensive materials—lowering by 10°C may save one grade in material costs.
Engineering testing: 4 mandatory tests
Test 1: PA66 long-term. 120-140°C, above that, use heat-resistant grades or upgrade the base material.
Test 2: Critical point. 80°C is the boundary between PA6/PA66, 150°C is the boundary between PA/high-temperature nylon.
Test 3: Temperature rise superposition. Inside a sealed chassis, 20-40°C higher than ambient temperature—must be tested.
Test 4: Cost range. PPS 2-3x, PEI 8-15x, PEEK 20-30x (relative to PA66).
Boundary Declaration
| Operating Conditions | Recommended Materials |
|---|
| < 80 °C | PA6 Universal, cost priority |
| 80-120° C | PA66 Oxidation- and Heat-Resistant System |
| 120-150℃ | PA46 or PA6T (dry) / low water absorption high-temperature nylon (wet) |
| 150-180°C | PA9T / PA10T / PPS |
| > 180°C | PPS / PEI / PEEK |
Engineering Memo
Four temperature levels: 80°C is the boundary between PA6 and PA66, 150°C is the boundary between PA and high-temperature nylon. Measured temperatures are more reliable than estimated ones; lowering by 10°C may save one grade of material.
Practical Case Study: Common Pitfalls and Correct Solutions
Pitfall 1: Choosing materials according to temperature, I found a conclusion but didn't check the applicable conditions, and directly applying it led to errors. Any quick reference table has prerequisites; conclusions taken out of context are wrong. Correct approach: When you see a conclusion, first find the conditions under which it holds—temperature, medium, time, and load type. Only when all four are complete should you dare to use it.
Pitfall 2: Copying someone else's material selection without considering your own process capabilities. The same material will have different results with different equipment and molds. Correct approach: Choose materials based on your own process level, and do not select materials beyond your equipment's capability. Pitfall 3: Treating quick reference tables as the final basis without actual testing. Correct approach: Use quick reference tables to narrow down options, but always verify with actual samples in the end.
Extended Judgment: Three Things to Confirm Before Choosing a Model
When selecting materials based on temperature, there are three things to clarify before choosing materials; if the order is wrong, everything afterward will need to be redone.
First: What is the long-term use temperature. Short-term peak temperature and long-term operating temperature are two different things. The heat distortion temperature on the material property table is a short-term indicator, and the long-term operating temperature is generally considered to be 70% of that.
Second: What kind of medium is it in contact with. Oil, water, cleaning agents, sweat, electrolyte—each will change the choice of material number. The list of media is more important than the temperature chart.
Third: Are there certification requirements? For flame retardancy, CTI, food contact, water-related hygiene, and safety certifications, if certification is required, changing the material number will require re-validation, which costs far more than the few dozen yuan difference in material price. Clarifying these three things is half the work done in material selection.
Write these three things into a table and send it to the supplier; it’s more useful than making ten phone calls—the communication cost for material selection based on temperature is mostly spent on repeatedly confirming these items.
Temperature Q&A Four Operations
Q: If a product is marked as resistant to 120 degrees, does that mean it can be used long-term? Most of the time, no. The marked temperature is mostly the heat deflection temperature or a short-term peak value; for long-term usage temperature, you need to specifically check aging data. Using the peak value as the long-term value when selecting materials is the most classic mistake in temperature-related issues.
Q: How do you convert between ambient temperature and material temperature? There is no fixed conversion, only actual measurement. Inside heated components, in areas attached to heat sources, or on surfaces directly exposed to sunlight, the difference between material temperature and ambient temperature can range from a few degrees to over a hundred degrees. Using an infrared gun together with a thermocouple for measurement is the most cost-effective and reliable combination.
Q: Are the material selections the same for intermittent high temperature and continuous high temperature? Not the same. Intermittent high temperature mainly considers short-term heat resistance and thermal deformation, while continuous high temperature requires looking at thermal aging lifespan, which is much more demanding. When discussing working conditions, these two terms need to be distinguished, as the answer could differ by one material grade.
Q: How do you determine the temperature setting at the critical point? Move up half a level, or modify the structure to reduce the temperature. Both options are better than gambling at the critical point. The money saved by choosing materials at the critical point is often not enough to cover a single batch failure.
Four-piece temperature measurement set
Toolize the task of temperature measurement and equip the full set of four tools. First: thermocouple plus inspection meter, for measuring internal and wall-adjacent temperatures—this is the main source of data. Second: infrared thermal imager, to scan the whole machine and find hot spots, determining where the thermocouples should be attached. Third: surface temperature stickers, attached to key parts to run with the device, with peak values read afterward, suitable for continuous monitoring during mass production.
Fourth item: a record sheet with three columns for points, time, and operating status, filed on the same day after measurement. The cost of having all four items is not high, and what you get in return is temperature data turned from mysticism into a ledger. When we do temperature diagnostics for clients, we use this set. After the first measurement, most clients will find at least one previously unknown hot spot. Hot spots are not scary; not knowing them is.
Design of high-temperature components focuses on reducing load
In addition to using better materials, temperature selection also partly depends on the design. Common four tricks: first, increase the distance to separate the material from the heat source, add insulation pads, or open heat dissipation holes. The cost is just a few cents, and the temperature grade can drop by one level; second, reduce wall thickness. Thick-walled parts dissipate heat slowly at the core, making the temperature higher than the surface. Thinning is equivalent to cooling the core.
Third, stagger peak times, so that high-temperature periods and periods of full-load stress do not coincide, for example, using structural designs that release pre-tension under high temperatures; Fourth, change the medium, using air cooling instead of relying on the material to withstand the heat. The common point of these four strategies is to adjust the structure before the material, as spending on structural modifications usually saves more than half compared to upgrading materials. By making concessions on both the design side and the material side, many seemingly intractable temperature problems can be solved. Selection indexing is a bottom-line thinking approach, while design load reduction is a spatial thinking approach; having both makes the solution more manageable.
Temperature records accompany the documents
The accumulation of temperature data is recommended to be made into files that follow the product: one temperature file per mass-produced product, recording the temperature distribution maps measured during the development period, key points, and the most severe working conditions. When the product is revised, the file is upgraded accordingly. The benefit of doing this becomes apparent after many years: when changing suppliers, materials, or designs, newcomers do not have to relearn the temperature field from scratch; they can simply open the file and continue.
Temperature is invisible, and archives make it visible and settle it down. This approach costs almost nothing; all it requires is the patience to measure a few extra times at the beginning. The work of selecting a temperature lies half in the moment of choosing the material and the other half in these invisible accumulations.
There is another common dilemma in temperature selection: the material price difference between the two levels is large, how to choose? Here's a judgment mnemonic: look at the temperature margin and the consequences of failure. If the margin is less than 20% or the consequences of failure are severe, choose the higher level; if the margin is sufficient and failures are repairable, you can stay at the lower level and increase monitoring frequency.
Behind the mnemonic is a simple probability calculation: high-grade material costs are a certain extra expense, while low-grade failures are probabilistic large expenses. Calculate the expected value, and the answer is usually clear on its own.
Conclusion
We hear this sentence every week — the earlier you ask about choosing materials, the easier it is.
The material selection and mold trial for this type of part can be discussed together.
