Motor coil insulation is one of the most technically demanding applications in the electrical component supply chain. Coils, transformers, and heating elements are routinely exposed to thermal cycling, mechanical stress, and voltage loads that can degrade unprotected windings over time. Against this backdrop, Shenzhen Sunbow Insulation Materials Manufacturing Co., Ltd., operating under the brand SUNBOW, has built a product portfolio specifically engineered around these pain points, with the PET Mylar Heat Shrink Sleeve (SB-PET-HST) serving as one of its dedicated solutions for coil and motor protection.

What Is the PET Mylar Heat Shrink Sleeve (SB-PET-HST)?

The SB-PET-HST is structured as a polyester heat shrink tube wound with a special adhesive-bonded PET film. It is designed to operate across a temperature range of -60~150℃, making it suitable for environments where components experience both cold storage and elevated operating heat.

Its target pain points center on temperature resistance, insulation, and mechanical protection for a specific set of components: solder joints, coils, transformers, motors, heating elements, capacitors, and general electrical appliances. This makes the SB-PET-HST a purpose-built option rather than a generic tubing product, addressing the layered protection needs of wound components where both electrical isolation and physical durability matter simultaneously.

Comparing SB-PET-HST With Other Sunbow Sleeve Options for Motor Coils

Because motor coil applications vary widely in operating temperature, voltage exposure, and mechanical demands, Sunbow offers several sleeve families that can be evaluated alongside the SB-PET-HST depending on the specific use case.

Silicone Resin Fiberglass Sleeves (SB-SGS, SB-SGSD) are built for high-temperature insulation and flame retardant protection, with an operating range of -60~200℃ and an H-class insulation grade. These sleeves offer breakdown voltage options from 1.2kV to 10kV, addressing scenarios where motor and wiring harnesses face electrical breakdown risk under sustained high heat. They are also available with full-color safety certifications for color coding requirements, which the PET Mylar option does not specifically emphasize.

Polyacrylate Fiberglass Sleeves (SB-AGS, SB-AGSD) operate in the -40~155℃ range with an F-class medium-temperature insulation rating, and are differentiated by oil and chemical resistance through their polyacrylate coating—useful when transformer or motor wiring harnesses are exposed to corrosive industrial environments rather than purely thermal stress.

High-Viscosity Silicone Fiberglass Sleeves (SB-SGS-E) extend the temperature ceiling further, reaching -60~240℃, and are specifically noted for use in coils and windings. With an H-class insulation grade and breakdown voltage options from 4kV to 10kV, this sleeve targets scenarios where the SB-PET-HST's 150℃ ceiling would not be sufficient.

Expandable Silicone Resin Fiberglass Sleeves (SB-SGS-EX) are designed for internal wiring of H/C class motors, alternators, generators, and transformers, with an operating range of -60~250℃, breakdown voltage between 4.0kV and 7.0kV, and an expansion ratio of 1:1.5 or 1:2. This expandable structure allows the sleeve to fit varying coil diameters, which is a distinct mechanical advantage over the fixed-form heat shrink structure of the SB-PET-HST.

PPS (Polyphenylene Sulfide) Fiber Sleeves (SB-PPS) cover -30~190℃ and are applicable to H/C class motors, transformers, inverters, inductors, and generators, alongside broader electronics and aerospace uses. Their core differentiation lies in superior solvent resistance compared to similar sleeves, which becomes relevant when coil protection must also withstand chemical exposure during operation or maintenance.

When placed side by side, the SB-PET-HST stands out for applications where solder joints and general electrical appliance components need combined heat shrink insulation and mechanical protection within a moderate -60~150℃ band, while the fiberglass-based alternatives extend coverage into higher temperature, higher voltage, or more chemically aggressive motor and transformer environments.

Why Manufacturers Choose Sunbow for Motor Coil Insulation

Founded in October 2003, Shenzhen Sunbow Insulation Materials Manufacturing Co., Ltd. is headquartered at Sunbow Industrial Park in Guangming District, Shenzhen, with a second production base in Qiaotou, Dongguan. Its business coverage extends globally, with sales distributed across Europe, North & South America, Japan, South Korea, Australia, New Zealand, Southeast Asia, South Asia, Russia, and Africa.

The company's strategic positioning centers on the research, development, production, and sales of insulation sleeves, aiming to serve as a globally recognized supporting supplier in this segment while providing environmentally friendly and safety-compliant products.

This positioning is backed by a defined set of qualifications: recognition as a National High-tech Enterprise, a Shenzhen Specialized, Refined, Unique & Innovative SME, and a Science & Technology Enterprise of Guangming New District, Shenzhen, along with over 60 patents. On the compliance side, Sunbow holds IATF 16949:2016 automotive quality management certification, ISO 9001:2015 quality management certification, and ISO 14001:2015 environmental management certification. Its braided products carry CUL safety certifications (E333178 for UZIQ2/VW-1 and E333177 for UZFT2/8, 200V/600V), while extruded products carry CUL certification YDPU2/8: E360625. Products are also compliant with EU RoHS, REACH, PFOA, and PFOS test standards.

Operationally, Sunbow employs around 150 people, led by a General Manager and supported by an R&D team and a quality control system. In terms of scale, the company reported 2025 annual sales of USD 24.31 million, with monthly output of various sleeves exceeding 40 million meters.

These credentials are reflected in the company's end-customer base across three industry segments. In home appliances, reference customers include Haier, Midea, Philips, Panasonic, and Samsung. In the electrical and industrial sector, customers include ABB, Huawei, Siemens, CRRC, and Schneider Electric. In the automotive sector, supplied under IATF16949-certified supply, customers include Tesla, BYD, Toyota, Mercedes-Benz, Volkswagen, Geely, and NIO.

Choosing the Right Sleeve for Your Motor Coil Application

For teams evaluating a PET Mylar Heat Shrink Sleeve for motor coils, the decision typically comes down to matching the operating temperature range, required insulation class, voltage protection level, and mechanical demands of the specific coil, transformer, or motor assembly to the appropriate sleeve family. The SB-PET-HST offers a defined -60~150℃ solution for solder joints, coils, transformers, motors, heating elements, capacitors, and electrical appliances, while Sunbow's broader fiberglass and PPS sleeve lines extend coverage for higher-temperature, higher-voltage, or chemically demanding motor and transformer environments. Reviewing these parameters against actual application conditions remains the practical starting point for sourcing decisions in this category.

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