华东有家做PVC型材的厂，换了一批树脂，挤出机温度调高一档想赶产量，结果料一出模口就发黄，机筒里还冒着HCl烟，一批型材颜色发暗过不了色差检验，师傅拆螺杆一看，内壁已经被腐蚀出印子。配方表一查，热稳定剂还是老配方，温度上去了体系没跟上。
PVC这东西，加工温度离分解温度就差那么几十度，热稳定剂就是替它扛这一段的。先花两分钟把家底摸清。
| 体系 | 代表品种 | 关键参数 | 典型制品 | 添加比例 |
|---|
| 钙锌复合 | 钙锌稳定剂 | 环保无铅,通用 | PVC管材/型材/片材 | 3%-5% |
| 有机锡 | 硫醇甲基锡 | 透明高,热稳定强 | 透明片材/食品级 | 1.5%-3% |
| 有机锡 | 马来酸丁基锡 | 耐候好 | 户外型材 | 1.5%-3% |
| 铅盐类 | 复合铅盐 | 便宜,稳定强 | 管材(有铅限制) | 3%-5% |
| 复合体系 | 钙锌+辅助稳定剂 | 多元协同 | 环保PVC | 合计4%-6% |
注：表中为行业通用范围，具体牌号与热稳定数据以厂家TDS为准。
PVC加工变色不是料差，是热稳定剂没跟上温度
讲之前先把这位护心符的底细交代清楚。宁波市科隆新材料有限公司长期供应PVC热稳定剂，钙锌复合、有机锡这些常用体系有稳定货源。热稳定剂说白了就是给PVC打护心符——PVC受热到一百六七十度就开始脱HCl，分子链一断就变色、变脆、还腐蚀设备。热稳定剂的活儿，就是把这个脱HCl的反应按住，让料在加工那几分钟里不崩。
做PVC的厂都懂，温度高一度，热稳定剂的负担就重一截。型材发黄、管子发暗、透明件雾度高，回头查十有八九是稳定体系不够，或者加工温度超了。投入也就一吨料里百分之几，可整件制品的外观和设备寿命都攥在它手里。
很多刚做PVC的有个误区，觉得稳定剂加得越多越保险。其实加多了会喷霜——制品表面冒一层白，擦都擦不掉，还影响印刷和粘接。行里有句话：稳定剂是味精，提鲜就行，放多了反而坏一锅汤。按工艺下限配，上机跑一批看看颜色和熔体，再微调，比一次堆上去稳得多。
PVC的加工窗口窄得像刀刃，热稳定剂就是那层护手的油。
图3 挤出机高温熔融出料
钙锌管环保通用，有机锡管透明耐候，选体系先看制品要求
热稳定剂分好几大类，各有地盘。钙锌复合是现在的主流，环保无铅，管材、型材、片材都能用，添加量百分之三到五；有机锡里的硫醇甲基锡透明性好、热稳定性强，透明片材、食品级制品爱用，就是价格高些；马来酸丁基锡耐候好，户外型材用得多；铅盐类便宜稳定，但环保上有铅限制，出口和内销高端订单基本不用。
怎么选？先看制品要什么。要透明、要食品级，上有机锡；要环保无铅走通用，上钙锌；要户外耐候，选马来酸类有机锡。别拿管材的方子套透明件，也别拿便宜铅盐套出口单。
再补个机制。PVC脱出来的HCl会自催化——越脱越多，越脱越快。热稳定剂不光要吸收掉HCl，还要把已经断的链封起来，防止继续断。所以体系里常搭辅助稳定剂，比如亚磷酸酯、环氧大豆油，帮着一起干活。单靠一个主稳定剂扛满负荷，加工窗口一压就崩。
还有个坑。钙锌体系初期白度好，可长期热稳定性不如有机锡，制品要求长时间加工或厚壁件，光靠钙锌不够。有机锡透明但跟含硫配方会反应，喷霜发雾。这些体系之间的禁忌，配的时候稍不留神就踩进去。
再说个政策层面的事。铅盐类热稳定剂虽然便宜稳定，可铅对环境和人体不友好，现在出口和内销高端订单基本都限用，欧美早有禁令，国内也在推无铅化。做管材、型材的厂，要是还在用铅盐体系，迟早得换钙锌。早换早主动，等客户一纸环保要求下来再临时找替代，价格和货期都被动。这也是为什么现在钙锌复合成了PVC热稳定的主力——不是它多神，是环保这把刀架在脖子上，不换不行。
一批型材发黄判废，够买几个月热稳定剂
厂方为什么要在热稳定剂上下功夫？从废品单说起。做PVC型材、管材、片材的厂，料一出模就发黄发暗，色差不过关整批判，螺杆腐蚀了还得停机拆修，一趟亏的钱够买几个月助剂。可热稳定剂一吨料里加百分之几，折算下来跟整件制品比真不算多。用这点钱把加工变色和设备腐蚀这两个坑填上，账怎么算都划算。
花这笔钱到底值在哪？值在制品不发黄、不因为色差退货、设备不被HCl腐蚀；值在热稳定数据每批可追，客户的外观和耐候要求才接得住；也值在添加量能跟着加工温度调——温度高了多补一点，温度低了收一点。
| 成本项 | 不加或省加 | 正常复配添加 | 差异说明 |
|---|
| 助剂采购 | 几乎为零 | 每吨几百到上千 | 占吨成本3%-6% |
| 加工变色 | 一出模就发黄 | 颜色匀 | 色差不过关就报废 |
| 设备 | HCl腐蚀螺杆 | 设备护得住 | 拆修停机花大钱 |
| 废品率 | 外观件整批判 | 批次稳定 | 良率差几个点 |
| 综合账 | 省助剂钱 | 小投入保整批和设备 | 废一批顶几个月助剂 |
自改还是买改性料？老规矩摊开比。自己买PVC树脂加稳定剂改，还是直接买配好的PVC混合料？
| 对比项 | 直接买PVC混合料 | 树脂+稳定剂自改 | 说明 |
|---|
| 料本 | 含加工费和利润 | 通常更低 | 行业通用口径 |
| 灵活度 | 挑现成牌号 | 按温度和颜色微调 | 南方北方气候不同 |
| 起订量 | 整吨起 | 稳定剂袋级 | 库存压力小 |
| 合规数据 | 供应商掌握 | 自己掌握热稳定数据 | 环保/食品文件在手 |
| 适合谁 | 用量小/认证严 | 有量有挤出机的厂 | 没测试能力别硬改 |
边界提醒：自己改PVC配方，得有转矩流变仪或者烘箱热稳定测试，没这个设备别上来就自改——热稳定这事不靠看颜色，靠数据。用量小、或者食品级/出口认证卡死的订单，直接买配好的料更省事。自改这碗饭不是谁都能端，掂量好再下嘴。
成本账再核一遍。改性料的出厂价，除了原料本身，还把加工费、包装、管销财费一并算进去，末了再加一层利润——通用料百分之五到十，工程料拉到百分之十五到二十五。买现成PVC混合料，这几层加价都由你承担；自改只进树脂加热稳定剂，原料是大头，加工那一段省下的加价，就是自改的空间。一天用料稳定、配方跑顺了的厂，自改这笔钱才挣得回来。
再给个直观对比。同样一吨PVC型材料，热稳定剂按工艺下限加，成本是低了，可一赶产量温度上去五度，料一出模就发黄，色差不过关整批判；按正常体系配足，助剂成本多了几十块，可温度敢按工艺走，产量和质量都稳。做PVC的厂都懂，温度一上去，稳定剂就是命根子，省它等于赌整批料。
再补个实操细节。加工温度不是越高越好，PVC到一百八以上脱HCl就明显加快，机筒里停留时间一长，稳定剂扛不住。所以做PVC的老师傅都讲究低温快出——温度压着工艺下限走，停留时间尽量短，稳定剂负担小，制品颜色才稳。自改配方时，别光盯着加多少稳定剂，先看看工艺温度是不是还有往下压的空间，两头一起抓才省得彻底。
同一种热稳定剂，放十个塑料品类里用法差出一截
热稳定剂不是一张方子打天下，换个PVC制品，体系和添加量都得调。宁波市科隆新材料给不同PVC配稳定体系时，先问做什么型材、透明还是不透明、要不要耐候，再推钙锌还是有机锡——管材要环保，透明片材要透光，问错方向配方就偏了。
| 塑料品类 | 典型场景 | 添加量范围 | 效果 | 注意事项 |
|---|
| PVC管材 | 给排水管 | 3%-5% | 不发黑不腐蚀 | 钙锌为主 |
| PVC型材 | 门窗型材 | 3%-5% | 耐候不褪色 | 选耐候型 |
| PVC透明片 | 吸塑/印刷片 | 1.5%-3% | 透明雾度低 | 有机锡 |
| PVC薄膜 | 包装膜 | 2%-4% | 热稳定好 | 薄膜低析出 |
| PVC电线 | 电线护套 | 3%-5% | 绝缘耐热 | 环保型 |
| PVC发泡 | 发泡板/装饰 | 3%-5% | 发泡均匀 | 配发泡剂 |
| 再生PVC | 回料制品 | 原配方补加 | 杂质多耗稳快 | 多补两到三成 |
| 软PVC | 人造革/软管 | 2%-4% | 耐老化 | 配增塑剂 |
| PVC瓶盖 | 密封垫片 | 2%-4% | 热稳定好 | 食品级选有机锡 |
还有个常被忽略的点：再生PVC里稳定剂已耗掉一部分，回料比例超三成，通常要补加原配方两到三成。回料掺得越多，稳定剂越不能跟着减，科隆新材配回收PVC体系时会把这事一并提示。
你手上要是正好有个PVC型材要赶产量、或者透明片材要换体系，钙锌和有机锡怎么搭心里没底，别急着下单。把制品、加工温度、月用量发来，科隆新材先帮你看方向、圈两三个候选体系。
从换树脂就发黄到稳定体系跟上，色差单翻篇了
下面是讲清热稳定逻辑拼出来的典型示例，对不上任何一家真实客户。浙江有家做PVC透明片材的厂，换了一批新树脂，挤出机温度往上提了五度想赶订单，结果片材一出模就发黄发雾，客户对着透光率一测不达标，两批货退了。
后来他们改成自己买PVC树脂，加有机锡稳定体系自改。宁波市科隆新材料有限公司给寄了公斤级样品，附了同批次热稳定时间数据。客户在自己的流变仪跑了热稳定对比，加工窗口比原来宽出一截。跑了三个月小批量，切过来，片材透光率稳了，温度也敢按正常工艺走。
他们也踩过坑。头一回温度上去了没补稳定剂，机筒里HCl冒出来腐蚀了螺杆；后来把稳定体系按温度重配，又加了辅助稳定剂，问题才稳住。这单说明：热稳定剂自改省的是料钱，前提是温度和体系对齐、数据别省。
这种踩坑在PVC厂里不算稀奇。宁波市科隆新材料有限公司这些年接过不少类似的单子——料做出来性能达标，就是一换树脂或一提温度就发黄，一查稳定体系没跟上。把钙锌或有机锡按工艺配足，再按实际温度重调添加量，多数问题都能解决。热稳定这事没有玄学，就是温度、体系、数据三样对不对得上。
热稳定剂怎么选，先看制品要求再翻牌号
下面把应用场景与推荐体系列成对照，照着找：
| 应用场景 | 推荐体系 | 添加量 | 注意事项 |
|---|
| 通用户外型材 | 钙锌耐候型 | 3%-5% | 环保无铅 |
| 透明片材 | 硫醇甲基锡 | 1.5%-3% | 透光率高 |
| PVC管材 | 钙锌复合 | 3%-5% | 长期热稳定 |
| 电线电缆 | 钙锌环保型 | 3%-5% | 绝缘耐热 |
| 食品级制品 | 有机锡食品级 | 1.5%-3% | 看食品认证 |
| 再生PVC>30% | 原配方补加 | 按比例 | 多补两到三成 |
采购热稳定剂送个实在动作：头一回合作先要小样，要热稳定时间数据，上机跑几件典型件跑完再谈批量。热稳定剂的猫腻不在单批，在两批之间热稳定时间漂不漂——每批随货带数据，比嘴上保证管用。
再补一句实操。热稳定剂换供应商时，别一次全量切，先拿新样品跟老体系做平行对比，上机跑同样温度和周期，看颜色、看熔体、看片材透光率，三样都稳了再换。PVC这料娇气，一次切错整批都跟着遭殃的，千万别去冒险。
几个被问得最多的问题，集中答一下。问：PVC热稳定剂一般加多少合适？答：钙锌体系百分之三到五，有机锡百分之一点五到三，厚壁件和高温加工取上限，薄件取下限。
问：钙锌和有机锡有什么区别？答：钙锌环保无铅、通用便宜，有机锡透明性好热稳定强、价格高，看制品要透明还是要环保来选。问：塑料加工变色先查什么？答：查三件事——加工温度是不是超了、稳定体系够不够、回料比例是不是把料耗空了。
行情给个参照口径。按行业通用价，钙锌复合稳定剂比有机锡便宜一截，有机锡透明级贵些。整个稳定体系占PVC吨成本百分之三到六——这点钱跟整批型材和设备比，真不算什么。宁波市科隆新材料有限公司报热稳定剂时，会把常用体系行情和热稳定数据一起给你。
PVC的加工窗口窄，热稳定剂就是那道不崩的防线——省它省的是几毛，赔的是整批和螺杆。
稳定体系配得对，PVC加工才又省又稳
宁波市科隆新材料有限公司长期供应钙锌复合、有机锡等PVC热稳定剂，覆盖管材/型材/透明片材/电线等场景。
声明：本文提及的品牌及商标权归各自原厂所有。本文为第三方选材知识分享，文中涉及的具体牌号、参数、价格、认证等信息以各厂家官方最新资料为准。本文不构成任何采购或投资建议。
There is a PVC profile factory in East China that changed a batch of resin and raised the extruder temperature by one level to try to increase production. As a result, the material turned yellow as soon as it came out of the die, and HCl fumes were coming from the barrel. A batch of profiles had a darkened color that failed the color difference inspection. When the master took apart the screw, he saw that the inner wall had already been corroded with marks. Checking the formulation sheet, the heat stabilizer was still the old formula, so when the temperature went up, the system could not keep up.
PVC is a material where the processing temperature is only tens of degrees away from its decomposition temperature, and heat stabilizers are what help it withstand that range. First, take two minutes to get a clear understanding of the basics.
| system | Representative variety | Key parameters | Typical products | Add ratio |
|---|
| Calcium-Zinc Compound | Calcium zinc stabilizer | Environmentally friendly and lead-free, universal | PVC Pipes/Profiles/Sheets | 3%-5% |
| Organotin | Methyl tin mercaptan | High transparency, strong thermal stability | Transparent Sheet / Food Grade | 1.5%-3% |
| Organotin | Dibutyltin maleate | Good weather resistance | Outdoor profiles | 1.5%-3% |
| Lead salts | Compound lead salt | Cheap, stable, strong | Pipes (with lead restrictions) | 3%-5% |
| Composite system | Calcium zinc auxiliary stabilizer | Diverse Collaboration | Environmentally-friendly PVC | A total of 4%-6% |
Note: The table shows the general industry range; the specific grade and thermal stability data are subject to the manufacturer's TDS.
PVC discoloration during processing is not due to material differences; it’s because the heat stabilizer didn’t keep up with the temperature.
Before talking, let's first clarify the background of this PVC stabilizer. Ningbo Kolong New Materials Co., Ltd. has been supplying PVC heat stabilizers for a long time, including calcium-zinc compound and organotin, which are common systems with stable supply. Simply put, heat stabilizers act like a protective charm for PVC—PVC starts releasing HCl when heated to 160–170 degrees Celsius, and once the molecular chains break, it discolors, becomes brittle, and even corrodes equipment. The job of the heat stabilizer is to suppress this HCl release reaction, preventing the material from collapsing during the few minutes of processing.
Any factory that makes PVC knows that when the temperature rises by one degree, the burden on the heat stabilizer increases significantly. If profiles yellow, pipes darken, or transparent parts become hazy, chances are high that the stabilizer system is insufficient or the processing temperature was too high. The amount added is only a few percent per ton of material, but it controls the appearance of the entire product and the lifespan of the equipment.
Many people who have just started working with PVC have a misconception, thinking that the more stabilizer you add, the safer it is. In fact, adding too much will cause blooming – a layer of white appears on the surface of the product, which can't be wiped off and also affects printing and bonding. There's a saying in the industry: a stabilizer is like MSG; just enough to enhance the flavor is fine, too much will ruin the whole pot. It's much more reliable to follow the lower limit of the process, run a batch to check the color and melt, and then make slight adjustments, rather than piling it in all at once.
The processing window of PVC is as narrow as a knife edge, and the heat stabilizer is like the protective oil for the hands.
Figure 3 Extruder high-temperature molten discharge
Calcium-zinc pipes are environmentally friendly and versatile, organic tin pipes are transparent and weather-resistant; when choosing a system, first look at the product requirements.
Heat stabilizers are divided into several major categories, each with its own domain. Calcium-zinc compounds are currently the mainstream, being environmentally friendly and lead-free, suitable for pipes, profiles, and sheets, with an addition amount of 3 to 5%. Organic tin compounds containing thiol methyl tin have good transparency and strong heat stability, popular for transparent sheets and food-grade products, though they are somewhat more expensive. Butyl tin maleate has good weather resistance and is often used in outdoor profiles. Lead salts are cheap and stable, but due to environmental lead restrictions, they are basically not used for high-end export or domestic orders.
How to choose? First, see what the product needs. If you need it to be transparent and food-grade, use organic tin; if you need it to be environmentally friendly and lead-free for general purposes, use calcium-zinc; if you need outdoor weather resistance, choose maleate-type organic tin. Don't use the formulation for pipes on transparent parts, and don't use cheap lead salts for export orders.
Let me add another mechanism. The HCl released from PVC will autocatalyze — the more that comes off, the more and faster it comes off. Heat stabilizers not only need to absorb the HCl, but also need to cap the already broken chains to prevent further breakage. Therefore, auxiliary stabilizers are often used in the system, such as phosphite esters and epoxidized soybean oil, to help out. Relying solely on a single primary stabilizer to bear the full load will collapse the processing window once pressure is applied.
There's another pitfall. The calcium-zinc system has good initial whiteness, but its long-term thermal stability is not as good as organic tin. For products that require long processing times or thick-walled parts, calcium-zinc alone is not enough. Organic tin is transparent but reacts with sulfur-containing formulations, causing frosting and clouding. The taboos between these systems are easy to step into if you're not careful when formulating.
Let's talk about a policy-related matter. Although lead salt heat stabilizers are cheap and stable, lead is not friendly to the environment or to human health. Nowadays, both exports and high-end domestic orders are basically restricted from using lead; Europe and the U.S. have long had bans, and China is also promoting lead-free alternatives. For factories producing pipes and profiles, if they are still using lead salt systems, they will sooner or later have to switch to calcium-zinc. The earlier the switch, the more proactive it is. Waiting until an environmental requirement comes from a client and then scrambling for a substitute will leave you at a disadvantage in terms of price and delivery time. This is also why calcium-zinc compounds have now become the mainstay of PVC heat stabilizers — not because they are miraculous, but because the environmental regulations hold a knife to your neck, and not switching is not an option.
A batch of profiles turned yellow and was deemed scrap, enough to buy several months' worth of heat stabilizer.
Why do manufacturers focus on heat stabilizers? Let's start with the scrap report. For factories producing PVC profiles, pipes, and sheets, the moment the material comes out of the mold it yellowed and darkened, with unacceptable color differences leading to batch rejection, and if the screw corrodes, production has to stop for repairs. The loss from one incident is enough to buy several months' worth of additives. Yet adding just a few percent of heat stabilizer per ton of material is not much compared to the cost of the whole product. Spending this small amount to prevent discoloration during processing and equipment corrosion is cost-effective no matter how you calculate it.
What is the real value of spending this money? The value lies in the product not yellowing, not being returned due to color differences, and the equipment not being corroded by HCl; it lies in the heat stability data being traceable for each batch, allowing customers' appearance and weather resistance requirements to be met; it also lies in the fact that the additive amount can be adjusted according to the processing temperature—add a little more when the temperature is high, and add a little less when the temperature is low.
| Cost item | Do not add or omit | Normal compounded addition | Difference Explanation |
|---|
| Auxiliary Materials Procurement | Almost zero | Several hundred to over a thousand per ton | Accounts for 3%-6% of the cost per ton |
| Processing discoloration | Turns yellow as soon as it comes out of the mold | Even color | If the color difference is not up to standard, it will be scrapped. |
| Equipment | HCl corrodes the screw | The equipment can be protected | Dismantling and repairing the machine costs a lot of money |
| Defect rate | Overall Appearance Batch Inspection | Batch stability | The yield rate is a few points lower |
| General account | Save money on additives | Small investment ensures the entire batch and equipment | A batch waste can last several months of additives |
Modify it yourself or buy modified material? Following the usual rule, let's compare. Do you buy PVC resin and add stabilizers yourself, or just buy pre-mixed PVC compound?
| Comparison item | Buy PVC compound directly | Resin Stabilizer Self-Modified | Explanation |
|---|
| material cost | Including processing fees and profit | Usually lower | Industry standard caliber |
| Flexibility | Choose an existing brand/model | Fine-tune by temperature and color | The climate is different between the south and the north. |
| Minimum order quantity | Starting from a whole ton | Stabilizer bag level | Low inventory pressure |
| Compliance data | Supplier Mastery | Master the thermal stability data yourself | Environmental protection/food documents in hand |
| Suitable for whom | Low dosage / Strict certification | Factories with both volume and extruders | If you don't have testing ability, don't force changes. |
Boundary reminder: If you want to modify a PVC formula yourself, you need a torque rheometer or an oven for thermal stability testing. Don't just start modifying without this equipment—thermal stability can't be judged by color, it relies on data. For small quantities or orders that are strictly food-grade/export certified, it's much easier to buy pre-prepared materials. Not everyone can handle this kind of work, so think carefully before you get involved.
Go over the cost accounting once more. For the ex-factory price of modified materials, in addition to the raw materials themselves, you also include processing fees, packaging, and administrative and financial expenses, and finally add a layer of profit—5% to 10% for general materials, 15% to 25% for engineering materials. If you buy ready-made PVC compound, all these markup layers are borne by you; if you modify it yourself, only resin and heat stabilizers are purchased, with raw materials being the largest cost, and the processing markup saved represents the space for self-modification. Only in factories where daily material use is stable and the formula runs smoothly can this self-modification profit be actually earned.
Let's give a more intuitive comparison. For the same ton of PVC material, if the heat stabilizer is added at the lower limit of the process, the cost is lower. But if you rush production and the temperature rises by five degrees, the material yellowing occurs right out of the mold, and the color difference fails, resulting in the whole batch being rejected. If you follow the normal formulation and add enough stabilizer, the additive cost increases by several tens of yuan, but then you can safely run the temperature according to the process, and both output and quality remain stable. PVC manufacturers all understand this: once the temperature rises, the stabilizer is crucial, and skimping on it is like gambling with the whole batch.
Let me add a practical detail. Higher processing temperatures are not always better. Once PVC goes above 180°C, HCl release accelerates significantly, and if the material stays in the barrel too long, the stabilizer can't handle it. So experienced PVC workers emphasize quick processing at low temperatures—keeping temperatures at the lower end of the process range and minimizing residence time reduces the load on the stabilizer and ensures stable product color. When modifying formulas yourself, don't just focus on how much stabilizer to add; first check if the process temperature can be lowered. Managing both aspects together is the best approach.
The same type of heat stabilizer can vary significantly in usage across ten different types of plastics.
Thermal stabilizers are not a one-size-fits-all solution; when switching PVC products, both the system and the dosage need to be adjusted. When Ningbo Cologne New Materials provides stabilization systems for different PVC formulations, they first ask what type of profile is being made, whether it should be transparent or opaque, and whether weather resistance is required before deciding on calcium-zinc or organic tin—pipes need to be environmentally friendly, transparent sheets need to be clear, and if you ask the wrong questions, the formula will go off track.
| Plastic products | Typical scenario | Addition range | Effect | Precautions |
|---|
| PVC pipes | Plumbing pipes | 3%-5% | Does not blacken or corrode | Mainly calcium and zinc |
| PVC profiles | Door and window profiles | 3%-5% | Weather-resistant and fade-proof | Choose weather-resistant type |
| PVC transparent sheet | Blister/Printed Sheet | 1.5%-3% | Low transparency haze | Organotin |
| PVC film | Packaging film | 2%-4% | Good thermal stability | Low-deposition film |
| PVC wire | wire sheath | 3%-5% | Insulation and heat resistance | Environmentally friendly |
| PVC foam | Foam Board/Decoration | 3%-5% | Uniform foaming | Foaming agent |
| Recycled PVC | Recycled Material Products | Supplement the original formula | High impurities, fast consumption and stabilization | Add 20% to 30% more |
| Soft PVC | Artificial leather / hose | 2%-4% | Aging resistant | With plasticizer |
| PVC bottle cap | Sealing gasket | 2%-4% | Good thermal stability | Food-grade selected organic tin |
There is another commonly overlooked point: part of the stabilizer in recycled PVC has been consumed, and when the proportion of recycled material exceeds 30%, it is usually necessary to add 20-30% more of the original formula. The more recycled material is mixed in, the less the stabilizer can be reduced. When Kolon New Materials formulates recycled PVC systems, this issue is highlighted as well.
If you happen to have a PVC profile that needs to increase production, or a transparent sheet that needs to switch systems, and you're unsure about how to combine calcium zinc and organic tin, don't rush to place an order. Send over the product, processing temperature, and monthly usage, and Colong New Materials will first help you look at the direction and identify two or three candidate systems.
From changing the resin and it turning yellow to the system stabilizing, the color difference has completely reversed.
Below is a typical example illustrating the logic of clarifying thermal stability, and it does not correspond to any real customer. There is a PVC transparent sheet manufacturer in Zhejiang that switched to a new batch of resin and increased the extruder temperature by five degrees to meet an order. As a result, the sheets turned yellow and hazy as soon as they came out of the mold, and when the customer measured the light transmittance, it did not meet the standard, resulting in two batches being returned.
Later, they switched to buying PVC resin themselves and modified it with their own organic tin stabilizer system. Ningbo Kolon New Materials Co., Ltd. sent kilogram-level samples along with thermal stability time data for the same batch. The customer ran a thermal stability comparison on their own rheometer, and the processing window turned out to be wider than before. After three months of small-batch trials, when they switched over, the sheet transparency stabilized, and the temperature could be run according to normal processing conditions.
They also ran into problems. The first time the temperature was increased without adding stabilizer, HCl came out in the barrel and corroded the screw; later, after re-adjusting the stabilizing system according to the temperature and adding an auxiliary stabilizer, the problem was finally stabilized. This case shows: saving on masterbatch by changing the heat stabilizer yourself only saves material costs, the premise is that the temperature and the system are aligned, and data should not be skimped on.
This kind of pitfall is not uncommon in PVC factories. Ningbo Kelon New Materials Co., Ltd. has handled quite a few similar orders over the years — the material would meet performance standards, but just by changing the resin or increasing the temperature, it would turn yellow. Upon investigation, the stabilization system was found not to be keeping up. By properly adjusting the amounts of calcium-zinc or organic tin according to the process, and then readjusting the dosage based on the actual temperature, most problems can be solved. Heat stabilization is not mystical; it just comes down to whether the temperature, system, and data align.
How to choose a thermal stabilizer: first look at the product requirements, then select the grade.
Below, match the application scenarios with the recommended body types and look for them accordingly:
| Application scenario | Recommendation system | Addition amount | Precautions |
|---|
| General-purpose outdoor profiles | Calcium-zinc weather-resistant type | 3%-5% | Environmentally Friendly and Lead-Free |
| transparent sheet | Methyl tin mercaptan | 1.5%-3% | High light transmittance |
| PVC pipes | Calcium-Zinc Compound | 3%-5% | Long-term thermal stability |
| Electric wires and cables | Calcium-Zinc Environmental Protection Type | 3%-5% | Insulation and heat resistance |
| Food-grade products | Food-grade organotin | 1.5%-3% | Check food certification |
| Recycled PVC >30% | Supplement the original formula | Proportionally | Add 20% to 30% more |
When purchasing heat stabilizers, a practical approach is to take concrete steps: for the first cooperation, request small samples, obtain heat stabilization time data, and run a few typical pieces on the machine before discussing bulk orders. The trick with heat stabilizers is not in a single batch, but whether the heat stabilization time drifts between batches — providing data with each batch is more effective than verbal promises.
One more practical tip. When changing the supplier of a heat stabilizer, don't switch the entire amount at once. First, take the new sample and do a parallel comparison with the old system, run it on the machine at the same temperature and cycle, check the color, the melt, and the sheet transparency. Only switch when all three are stable. PVC is a delicate material; if you make the wrong switch, the entire batch will suffer, so don't take the risk.
A few of the most frequently asked questions are answered together. Question: How much PVC heat stabilizer is generally appropriate? Answer: For the calcium-zinc system, 3% to 5%; for organotin, 1.5% to 3%. Use the upper limit for thick-walled parts and high-temperature processing, and the lower limit for thin parts.
Q: What is the difference between calcium-zinc and organic tin? A: Calcium-zinc is environmentally friendly and lead-free, general-purpose and cheap; organic tin has good transparency, strong thermal stability, and is expensive. Choose based on whether the product needs to be transparent or environmentally friendly.
Q: What should be checked first when plastic processing causes discoloration? A: Check three things — whether the processing temperature is too high, whether the stabilization system is sufficient, and whether the proportion of recycled material has depleted the raw materials.
Provide a reference benchmark for the market price. According to the industry standard price, calcium-zinc composite stabilizers are somewhat cheaper than organotin, while organotin transparent grade is a bit more expensive. The entire stabilizer system accounts for 3% to 6% of the PVC per-ton cost—compared to the cost of the whole batch of profiles and equipment, this amount really isn't much. When Ningbo Kolon New Materials Co., Ltd. quotes hot stabilizers, they will provide you with both the market prices of commonly used systems and the heat stabilization data.
PVC has a narrow processing window, and the heat stabilizer is the unbreakable line of defense — saving a few cents on it could cost an entire batch and the screw.
The system is properly matched, so PVC processing becomes both economical and stable.
Ningbo Kelong New Materials Co., Ltd. has long supplied PVC heat stabilizers such as calcium-zinc compounds and organotin, covering applications in pipes/profiles/transparent sheets/wires, etc.
Statement: The brands and trademarks mentioned in this article are owned by their respective manufacturers. This article is a third-party material selection knowledge sharing, and the specific grades, parameters, prices, certifications, and other information mentioned in the text are subject to the latest official information from the manufacturers. This article does not constitute any procurement or investment advice.
