Sumitomo Bakelite Develops Thermosetting Resin Laminate with High Tracking Resistance (900V)
Key facts
- Sumitomo Bakelite Develops Thermosetting Resin Laminate with High Tracking Resistance (900V)
- Sumitomo Bakelite Co., Ltd. has developed a thermosetting resin laminate with excellent tracking resistance and insulation properties. This new material achieves 900V tracking resistance and contributes to the miniaturization and high efficiency of insulating components used in high-voltage applications such as xEVs and industrial power supplies.
- Source: PR Times
- Date: June 12, 2026
Direct answer
Sumitomo Bakelite Co., Ltd. has developed a thermosetting resin laminate with excellent tracking resistance and insulation properties. This new material achieves 900V tracking resistance and contributes to the miniaturization and high efficiency of insulating components used in high-voltage applications such as xEVs and industrial power supplies.
- Citation
- Sumitomo Bakelite Develops Thermosetting Resin Laminate with High Tracking Resistance (900V) (June 12, 2026), PR Times
- Source
- PR Times
- Date
- June 12, 2026
Sumitomo Bakelite Co., Ltd. has developed a thermosetting resin laminate with excellent tracking resistance and insulation properties. This new material achieves 900V tracking resistance and contributes to the miniaturization and high efficiency of insulating components used in high-voltage applications such as xEVs and industrial power supplies.
📋 Article Processing Timeline
- 📰 Published: June 12, 2026 at 20:38
- 🔍 Collected: June 12, 2026 at 11:51
- 🤖 AI Analyzed: June 12, 2026 at 16:52 (5h 0m after Collected)
Sumitomo Bakelite Co., Ltd. (Headquarters: Shinagawa-ku, Tokyo; President: Shinichi Kajiyoshi) has developed a prepreg and laminate with excellent tracking resistance and insulation properties using diallyl phthalate (DAP) resin. It features tracking resistance of 900V, high dielectric breakdown strength and dielectric reliability, high strength due to composite material with glass cloth, and heat resistance due to thermosetting resin, contributing to applications such as insulating parts and structural members used in high-voltage environments like xEVs, industrial power supplies, and electronic equipment.
Background of Development
We have been providing phenolic resin laminates and epoxy resin laminates to the market. Leveraging the compounding technology cultivated through these products, we are actively engaged in the development of new materials and high value-added products beyond those.
To respond to the trend of increasing voltages in society, we have developed a material that possesses high insulation, high tracking resistance, and heat resistance using diallyl phthalate (DAP) resin, which is a thermosetting resin, and further combines it with glass cloth to achieve the high strength characteristic of laminates.
Features of the Developed Product
This developed product has confirmed performance of 900V tracking resistance in the STT test*1, a tracking resistance standard UL2597 (see Table 1 below). It also exhibits properties such as high elastic modulus in dielectric breakdown voltage and at high temperatures, realizing high insulation, heat resistance, and high strength in addition to tracking resistance.
Table 1: UL2597 STT Test Results
Item
Unit/Condition
High Insulation / High Tracking Resistance Laminate
Tracking Resistance
V, UL2597 STT
900
Flame Retardancy
Compliant with UL94
Tested internally
Equivalent to V-0 (0.8mm thickness)
Specific Gravity of Insulating Layer
-
2.1
Dielectric Breakdown Voltage
kV/mm
40
Flexural Modulus
GPa
23 (25°C), 14 (175°C)
Furthermore, due to its excellent insulation and durability even in high-voltage environments, it enables thinner insulating materials*2 and shorter conductor spacing*3, contributing to the miniaturization, thinning, and high efficiency of electrical components (see Graph 1 below).
In addition, this developed product supports large areas (1m x 1m), making it applicable to sizes that were difficult to handle with conventional molding materials.
*1 The conventional tracking resistance test standard, CTI (Comparative Tracking Index Test) based on IEC 60112, had an upper test voltage limit of 600V. However, in response to the increasing demands for electrical properties of materials, the STT (Surface Tracking Test) based on the new standard UL 2597, developed by UL Standards & Engagement, allows testing up to a maximum of 900V.
*2 Materials with low insulation require thickness to ensure sufficient insulation, while materials with high insulation can be made thinner.
*3 Materials with low tracking resistance (durability) may cause conduction or short circuits if the distance between conductors is reduced. However, by using materials with excellent tracking resistance, insulation can be ensured even with reduced conductor spacing.
Graph 1: Interlayer Insulation Reliability Test Results (Applied Voltage: 4kV, Test Conditions: 85°C/85% RH)
Future Plans
Moving forward, we will proceed with sample provision and aim to collaborate with our other high tracking resistance products (molding materials, powder coatings) to offer proposals tailored to customer usage patterns and needs.
High Tracking Resistance Product Lineup
Inquiries Regarding This Matter
Sumitomo Bakelite Co., Ltd. Materials Solution Sales Division, Substrate Materials Sales Department
TEL: 03-5462-4079
Inquiry Form https://inquiry.sumibe.co.jp/m/j_circuit_circuitry/
Keywords:
Background of Development
We have been providing phenolic resin laminates and epoxy resin laminates to the market. Leveraging the compounding technology cultivated through these products, we are actively engaged in the development of new materials and high value-added products beyond those.
To respond to the trend of increasing voltages in society, we have developed a material that possesses high insulation, high tracking resistance, and heat resistance using diallyl phthalate (DAP) resin, which is a thermosetting resin, and further combines it with glass cloth to achieve the high strength characteristic of laminates.
Features of the Developed Product
This developed product has confirmed performance of 900V tracking resistance in the STT test*1, a tracking resistance standard UL2597 (see Table 1 below). It also exhibits properties such as high elastic modulus in dielectric breakdown voltage and at high temperatures, realizing high insulation, heat resistance, and high strength in addition to tracking resistance.
Table 1: UL2597 STT Test Results
Item
Unit/Condition
High Insulation / High Tracking Resistance Laminate
Tracking Resistance
V, UL2597 STT
900
Flame Retardancy
Compliant with UL94
Tested internally
Equivalent to V-0 (0.8mm thickness)
Specific Gravity of Insulating Layer
-
2.1
Dielectric Breakdown Voltage
kV/mm
40
Flexural Modulus
GPa
23 (25°C), 14 (175°C)
Furthermore, due to its excellent insulation and durability even in high-voltage environments, it enables thinner insulating materials*2 and shorter conductor spacing*3, contributing to the miniaturization, thinning, and high efficiency of electrical components (see Graph 1 below).
In addition, this developed product supports large areas (1m x 1m), making it applicable to sizes that were difficult to handle with conventional molding materials.
*1 The conventional tracking resistance test standard, CTI (Comparative Tracking Index Test) based on IEC 60112, had an upper test voltage limit of 600V. However, in response to the increasing demands for electrical properties of materials, the STT (Surface Tracking Test) based on the new standard UL 2597, developed by UL Standards & Engagement, allows testing up to a maximum of 900V.
*2 Materials with low insulation require thickness to ensure sufficient insulation, while materials with high insulation can be made thinner.
*3 Materials with low tracking resistance (durability) may cause conduction or short circuits if the distance between conductors is reduced. However, by using materials with excellent tracking resistance, insulation can be ensured even with reduced conductor spacing.
Graph 1: Interlayer Insulation Reliability Test Results (Applied Voltage: 4kV, Test Conditions: 85°C/85% RH)
Future Plans
Moving forward, we will proceed with sample provision and aim to collaborate with our other high tracking resistance products (molding materials, powder coatings) to offer proposals tailored to customer usage patterns and needs.
High Tracking Resistance Product Lineup
Inquiries Regarding This Matter
Sumitomo Bakelite Co., Ltd. Materials Solution Sales Division, Substrate Materials Sales Department
TEL: 03-5462-4079
Inquiry Form https://inquiry.sumibe.co.jp/m/j_circuit_circuitry/
Keywords:
FAQ
What are the benefits of this new material?
It offers 900V tracking resistance, exceeding conventional 600V standards, contributing to equipment miniaturization and higher efficiency. It also possesses high strength and heat resistance.
What kind of products will it be used in?
It is expected to be used as insulating components in electric vehicles (xEV) powertrains, industrial power supplies, and other electronic devices operating at high voltages.
What is tracking resistance?
It is the resistance of an insulating material's surface against the formation of conductive paths (tracks) due to contamination or other factors when voltage is applied, which can lead to short circuits.
How does it differ from conventional materials?
The key difference is its ability to be tested at 900V, exceeding the conventional test standard limit of 600V, allowing it to handle more demanding high-voltage environments.
How will it be integrated with Sumitomo Bakelite's other products?
We aim to provide comprehensive proposals tailored to customer needs by collaborating with existing high tracking resistance products such as molding materials and powder coatings.