1. Introduction 引言

Electrical cables deployed in polar regions, northern mining sites, and cryogenic industrial facilities must retain mechanical flexibility at temperatures far below the freezing point of water. While standard Chlorinated Polyethylene (CPE) jacketing provides excellent flame retardance, oil resistance, and UV stability, it becomes increasingly stiff as ambient temperatures drop below approximately −25 °C. This presents a serious engineering challenge: a rigid cable jacket cannot be routed, bent around pulleys, or connected to moving machinery without risking cracks, insulation damage, or total conductor exposure.

（在极地、北方矿区及低温工业环境中运行的电缆必须在远低于 0 °C 的温度下保持机械柔性。标准 CPE 护套虽具有优异的阻燃、耐油和耐紫外线性能，但在约 −25 °C 以下会变得僵硬，给布线、弯曲和动态连接带来开裂风险。）

AmerCable — now part of Mattr (TSX-listed) following its acquisition in January 2025 — has long marketed “Arctic Grade” versions of its CIR®, DLO, and Tiger® Brand mining cables, rated for operation down to −50 °C and even −60 °C depending on the product line. The key question from a compounding and materials-science perspective is: what plasticizer chemistry enables a CPE- or EPR-based jacket to remain pliable at −60 °C, where standard CPE would be well past its glass-transition temperature (T_g)?

（AmerCable（2025 年 1 月被 Mattr 收购）长期推出”Arctic Grade”系列电缆，在 −50 °C 甚至 −60 °C 下仍保持柔性。关键技术问题是：何种增塑剂化学体系使 CPE 或 EPR 基护套在 −60 °C 仍可弯曲？）

2. Fundamentals of Cold-Flex Jacket Design 低温柔性护套设计基础

2.1 Glass Transition Temperature (T_g) 玻璃化转变温度

Every amorphous or semi-crystalline polymer has a characteristic glass-transition temperature (T_g) below which molecular chain segments lose their mobility and the material transitions from a rubbery, flexible state to a glassy, brittle state. For cable jacket engineering, the practical low-temperature limit of a compound is typically 5–15 °C above its measured T_g, because operational bending and impact loads require a margin of safety.

（每种非晶或半结晶聚合物都有其玻璃化转变温度 T_g，低于该温度分子链段失去运动能力，材料从柔韧态转变为脆性态。在电缆工程中，实际最低使用温度通常比 T_g 高 5–15 °C，以确保弯曲和冲击的安全裕量。）

As shown in Table 1, unplasticized CPE has a T_g in the range of −15 to −25 °C. This means standard CPE jackets become unreliable below roughly −10 to −20 °C. In contrast, EPR/EPDM compounds inherently possess a much lower T_g, which is why AmerCable uses EPR as the inner insulation layer in its DLO (Diesel Locomotive Cable) product line and why EPR-based jackets can withstand cold down to approximately −60 °C.

（如表 1 所示，未增塑 CPE 的 T_g 约为 −15 至 −25 °C。EPR/EPDM 本身 T_g 更低，这解释了 AmerCable 在 DLO 电缆内层使用 EPR 绝缘的原因，以及 EPR 基护套能耐受约 −60 °C 低温的机理。）

2.2 The Role of Plasticizers 增塑剂的作用

Plasticizers are low-molecular-weight organic compounds added to polymer formulations to increase chain mobility, lower T_g, and improve flexibility. In the context of cable jackets, plasticizer selection directly determines the cold-bend performance, long-term aging behavior, and extraction resistance of the final product. As noted by Anixter in their cable jacket technical guide, jackets can be modified by the addition of fillers, plasticizers, activators, and inhibitors to enhance particular physical characteristics.

（增塑剂是添加到聚合物中的低分子量有机化合物，用以增加链段运动性、降低 T_g、改善柔性。增塑剂的选择直接决定电缆护套的低温弯曲性能、长期老化行为和耐萃取性。）

3. AmerCable Arctic Brand: Architecture and Materials AmerCable Arctic 系列：结构与材料

AmerCable (headquartered in El Dorado, Arkansas, USA; ISO 9001:2015 certified) manufactures several cable families that carry the “Arctic Grade” designation. The most relevant product lines include:

（AmerCable 总部位于美国阿肯色州，通过 ISO 9001:2015 认证，多个产品系列带有”Arctic Grade”标识。主要包括：）

A critical engineering detail in AmerCable’s DLO cable line is the use of a two-layer composite jacket consisting of a flame-retardant, oil- and sunlight-resistant Chlorinated Polyethylene (CPE) outer layer combined with an Ethylene-Propylene Rubber (EPR) inner layer. This composite design achieves significant diameter reduction compared to full-thickness single-material jackets while leveraging the inherently superior cold-flex properties of EPR.

（AmerCable DLO 电缆的关键设计在于采用双层复合护套：外层为阻燃、耐油、耐紫外线的 CPE，内层为 EPR 橡胶。此复合结构既缩小了外径，又利用了 EPR 固有的优异低温柔性。）

4. Plasticizer Chemistry for −60 °C Flexibility 实现 −60 °C 柔性的增塑剂化学

Achieving operational flexibility at −60 °C requires either selecting a base polymer with an inherently low T_g (such as EPR/EPDM), or heavily plasticizing a higher-T_g polymer (such as CPE) with cold-performance plasticizers — or, most commonly in industrial practice, a combination of both strategies.

（实现 −60 °C 柔性需要：选用固有 T_g 极低的基体（如 EPR/EPDM），或对 T_g 较高的聚合物（如 CPE）大量添加耐寒增塑剂，或二者结合。）

4.1 Key Plasticizer Families for Cold-Flex Cables 关键增塑剂系列

4.2 DOS — The Premier Cold-Flex Plasticizer DOS — 首选低温增塑剂

Dioctyl Sebacate (DOS) is widely regarded as one of the most effective cold-resistant plasticizers available for cable compounding. It is a diester produced by reacting sebacic acid (derived from castor oil, a bio-based feedstock) with 2-ethylhexanol. DOS possesses an exceptionally low freezing point (approximately −48 to −55 °C in its neat form) and maintains excellent plasticizing efficiency at cryogenic temperatures. Materials compounded with DOS can retain flexibility and impact resistance down to approximately −60 to −50 °C, making it the plasticizer of choice for arctic-grade cable jacket formulations.

（癸二酸二辛酯（DOS）被公认为最有效的耐寒增塑剂之一。其凝固点极低（约 −48 至 −55 °C），添加 DOS 的材料可在 −60 至 −50 °C 保持柔性和抗冲击性，是极地级电缆护套配方的首选增塑剂。）

4.3 DOA — Widely Used, Slightly Less Extreme DOA — 广泛应用，低温性能稍逊

Dioctyl Adipate (DOA, CAS 123-79-5) is the second most common cold-flex plasticizer in cable manufacturing. DOA provides flexibility down to approximately −60 °C (around −76 °F) and offers good electrical insulation properties, which are critical for wire and cable coatings. It is compatible with PVC, CPE, nitrocellulose, ethyl cellulose, and most synthetic rubbers. However, DOA has somewhat higher volatility than DOS, meaning it may slowly migrate out of the compound over extended service life, particularly at elevated operating temperatures.

（己二酸二辛酯（DOA）是电缆制造中第二常见的耐寒增塑剂，可提供约 −60 °C 的柔性，电绝缘性能良好。但其挥发性略高于 DOS，在高温长期运行中可能缓慢析出。）

4.4 Plasticizer Selection in CPE for Arctic Cables 极地电缆 CPE 增塑剂选择

According to the technical literature from ChemCeed, CPE is compatible with a wide variety of plasticizers, and the types used in CPE formulations are similar to those used in PVC, including adipates, phthalates, and trimellitates. Common choices for general performance include DINP, DOP, and DOTP, while specialty cold-performance plasticizers such as DOA, DINA, DBS, DOS, TOTM, and TINTM are selected for extreme-temperature applications. For achieving −60 °C flexibility in a CPE jacket, the compound would typically incorporate DOS or DOA (or a synergistic blend of both) at loading levels of 25–45 phr (parts per hundred resin), potentially combined with paraffinic or naphthenic process oils.

（据 ChemCeed 技术资料，CPE 与多种增塑剂兼容，包括己二酸酯、邻苯二甲酸酯和偏苯三酸酯。实现 −60 °C 柔性通常需在 CPE 中添加 DOS 或 DOA（或二者协同共混），用量 25–45 phr，并可配合石蜡油或环烷油。）

5. Head-to-Head: Arctic-Grade CPE vs. Standard CPE 对比：极地级 CPE 与标准 CPE

6. The EPR/EPDM Alternative Path EPR/EPDM 替代方案

For applications requiring the most extreme cold flexibility, some cable manufacturers bypass CPE altogether and use Ethylene Propylene Rubber (EPR) or its terpolymer variant EPDM as the jacket material itself. As documented by Anixter and Wiring Harness News, EPR jackets offer excellent heat, abrasion, and oxidation resistance while withstanding cold temperatures down to −60 °C, owing to the inherently low T_g of the ethylene-propylene copolymer backbone. AmerCable’s DLO cable takes a hybrid approach: the inner insulation layer is EPR, providing the cryogenic flexibility, while the outer layer is CPE, providing flame retardance, oil resistance, and UV protection.

（对于需要极端低温柔性的应用，可直接使用 EPR/EPDM 作为护套。EPR 护套耐热、耐磨、耐氧化，可耐受 −60 °C 低温。AmerCable DLO 电缆采用混合方案：内层 EPR 提供低温柔性，外层 CPE 提供阻燃、耐油和紫外防护。）

7. Applicable Standards and Test Methods 适用标准与试验方法

The cold-bend and cold-impact performance of cable jackets is evaluated according to established industry standards. The following standards are most relevant to the cable types discussed in this article:

（电缆护套低温弯曲和低温冲击性能按行业标准评估，以下标准与本文讨论的电缆类型最为相关：）

8. Practical Guidance: Selecting Cold-Flex Cables 实践指南：低温柔性电缆选型

8.1 Temperature Tier Selection 温度等级选择

8.2 Key Specifications to Verify 需验证的关键规格

When procuring arctic-grade cables, engineers should request and verify the following from the manufacturer’s test reports: cold-bend test temperature (per ASTM D2137 or equivalent), cold-impact test temperature, plasticizer type and loading level (phr), aging test data (heat aging at 90–100 °C × 168 h, then re-test cold bend), and oil immersion test results. If the cable will be used in dynamic/flexing applications (trailing cables, hoist systems, reel cables), the flex-life test data at the rated minimum temperature should also be reviewed.

（采购极地级电缆时，工程师应向制造商索取以下测试数据：低温弯曲试验温度、低温冲击试验温度、增塑剂种类和用量、老化试验数据（90–100 °C × 168 h 后复测低温弯曲）以及耐油浸泡结果。动态/弯曲应用还需审查额定最低温度下的弯曲寿命数据。）

9. Conclusion 结论

The achievement of −60 °C flexibility in cable jackets is fundamentally a plasticizer engineering challenge when working with CPE-based compounds, and a base-polymer selection advantage when working with EPR/EPDM. AmerCable’s Arctic Brand products leverage both strategies — using EPR as an insulation or inner jacket layer for its inherently low T_g, while formulating the outer CPE jacket with high loadings of sebacate (DOS) and/or adipate (DOA) plasticizers to depress the compound’s brittleness point below −50 °C.

（实现 −60 °C 电缆护套柔性，在 CPE 体系中本质上是增塑剂工程挑战，在 EPR/EPDM 体系中则是基体选材优势。AmerCable Arctic 系列两策并用：利用 EPR 的固有低 T_g 作为绝缘或内层护套，同时在外层 CPE 中高比例添加 DOS/DOA 增塑剂，使复合护套脆性点降至 −50 °C 以下。）

For engineers specifying cables for extreme-cold environments, the takeaway is clear: always verify the specific plasticizer chemistry and cold-test data, not just the rated temperature printed on the cable legend. The difference between a −40 °C cable and a −60 °C cable often comes down to the choice between DOTP and DOS in the compounding recipe.

（对于在极端低温环境中选型的工程师，关键是：始终核实具体的增塑剂化学成分和低温试验数据，而不仅仅是印在电缆标识上的额定温度。−40 °C 与 −60 °C 电缆的差异通常取决于配方中 DOTP 与 DOS 的选择。）