Description
Electrical insulating crepe paper is produced from high‑purity kraft or sulfate insulating wood pulp, ensuring low ash, chloride, and sulfate content for stable dielectric performance in oil‑filled equipment. The creping process increases paper elongation, surface area, and tear resistance, allowing it to wrap tightly around irregular profiles and retain more insulating oil for improved cooling.
SIDA’s portfolio covers standard crepe, high‑crepe and calendered grades, as well as aluminium‑laminated and thermally upgraded variants designed for Class A and higher thermal classes depending on the system design. Typical uses include lead insulation, tap lead wrapping, interlayer insulation, shielding, and stress relief in distribution and power transformers, instrument transformers (CT, PT, CVT), and dry‑type equipment.
Aluminium Crepe Paper – 90/135 combines creped insulation paper with aluminium foil to provide electrostatic shielding with moderate eddy current losses while maintaining high flexibility for tight bends. Denission Crepe Paper – 35 HC, Alutherm Paper, Crepe Paper – 22 HCC, and Crepe Paper – 510 C are commonly used in the transformer industry as standardized grades for lead wrapping, spacers, and stress cone insulation.
Typical technical data
Values below are representative industry values for electrical crepe insulation papers and related products; specific SIDA data can be aligned to customer drawings and standards.
General crepe paper (cellulosic) – typical values
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NINGBO SIDA NEW MATERIAL CO.,LTD. |
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Test Report |
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Product name:Crepe Paper |
Thickness:0.65mm (550*1200m) |
Test time：2026.1 |
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Item |
Unit |
Requirement standard |
Result |
Test method |
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Thickness |
mm |
0.55–0.75 |
0.679 |
JB/T10441.3- 2004 |
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Base weight |
g/cm3 |
160-240 |
194.7 |
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Density |
g/cm3 |
0.29 |
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Tensile Strength |
Kg/15mm |
MD≥6.0 |
6.9 |
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Elongation a |
% |
MD≥120 |
134.9 |
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Dielectric Breakdown Stregnth |
KV |
Ave.≥1.50 Min.≥1.30 |
Ave.1.72 Min,1.62 |
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Moisture Content |
% |
≤8.0 |
4.3 |
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Ash Content |
% |
≤0.7 |
0.249 |
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Protuberances |
Numbers/inch |
20–40 |
23 |
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Testing result |
Pass |
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Note:The product specifications provided are for reference purposes only. Please refer to the actual product for final specifications. We also offer various sizes and thicknesses to meet your specific needs. For further customization, please contact us.
Aluminium Crepe Paper – 90/135 (shielding grade – indicative)
| Parameter | Typical value |
|---|---|
| Structure | Crepe paper laminated with aluminium foil |
| Overall thickness | 0.12 – 0.20 mm (paper + foil) |
| Crepe / elongation | 30 – 80% MD depending on base grade |
| Function | Electrostatic shielding and turn/lead insulation |
| Dielectric strength | ≥ 8 kV/mm through paper layer; foil provides barrier |
Denission Crepe Paper – 35 HC / Crepe Paper – 22 HCC / Crepe Paper – 510 C
Industry often uses the 35/22/510 nomenclature to indicate base paper weight, elongation, and crepe level; values below align with common technical sheets.
| Grade | Thickness (mm) | Crepe / elongation (%) | Base weight (approx.) | Typical use |
|---|---|---|---|---|
| Denission Crepe Paper – 35 HC | 0.20 – 0.25 | 50 – 100 (high crepe) | 35 lb/3000 ft² class | Lead wrapping and corner relief in transformers |
| Crepe Paper – 22 HCC | 0.12 – 0.18 | 80 – 150 (high crepe) | 22 lb/3000 ft² class | Tight lead bends, stress relief wrapping |
| Crepe Paper – 510 C | 0.90 – 1.05 | 20 – 40 (coarse crepe) | 60–75 lb/3000 ft² class | Barrier insulation, spacers, tap blocks |
Press Paper K‑Buff 0.1 mm to 1.0 mm
Presspaper (flat insulation) is used together with crepe paper where rigid mechanical support is required.
| Parameter | Typical value |
|---|---|
| Thickness range | 0.10 – 1.00 mm |
| Base material | Electrical pressboard/presspaper (cellulose) |
| Density | 0.9 – 1.2 g/cm³ |
| Dielectric strength in oil | ≥ 15 kV/mm |
| Application | Cylinders, spacers, barriers, slot insulation |
Filament Reinforced Paper Tape
| Parameter | Typical value |
|---|---|
| Structure | Crepe or kraft paper reinforced with glass/polyester filaments |
| Thickness | 0.10 – 0.25 mm typical |
| Tensile strength | ≥ 100 N/10 mm (high due to filaments) |
| Application | Binding, securing winding ends, mechanical reinforcement of insulation |
(Note: Crepe Paper – 67/100, 60/170, 60/90 and Alutherm Paper are positioned similarly within this family as intermediate crepe levels and thermally upgraded/laminated variants; site‑specific tables can mirror the above with thickness and elongation tuned per SKU.)
Testing standards and quality
SIDA Crepe Paper and related products are designed to comply with relevant international electrical insulation standards used in the transformer industry. While exact standards depend on customer specification, the following are typically referenced for design and type testing of insulation systems:
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IEC 60554: Cellulosic papers for electrical purposes – defines requirements for electrical kraft and crepe papers.
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IEC 60085: Electrical insulation – Thermal evaluation and designation; used to classify insulation systems (e.g., Class A 105 °C).
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IEC 60641 / IEC 60674 or equivalent: Pressboard and presspaper, and flexible insulating materials used with crepe and presspaper components.
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IEC 60076 series / IEEE transformer standards: Define performance requirements for power and distribution transformers and the insulation systems used within them.
Routine factory quality checks normally include basis weight, thickness, crepe percentage, tensile strength, elongation, dielectric strength in oil, and moisture content to ensure batch‑to‑batch consistency. For aluminium and reinforced products, adhesion between layers and tensile strength of the composite are also verified.
Application scenarios
Power and distribution transformers
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Used for lead insulation, joints, tap changers, connection points, and areas with tight bending radii where flat presspaper would crack or gap.
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Aluminium Crepe Paper – 90/135 adds electrostatic shielding around leads and windings, especially in high‑voltage and instrument transformers.
Instrument transformers and bushings
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Widely applied in CTs, PTs, and CVTs for making leads, shields, and local barriers where high electric field stress occurs.
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High‑crepe grades such as Denission Crepe Paper – 35 HC and Crepe Paper – 22 HCC are ideal for stress relief in RIP and RBP bushing designs.
Motors, reactors, and cables
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Used as interlayer and turn insulation in dry‑type transformers and medium‑voltage motors for improved flexibility and oil/varnish impregnation.
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Crepe Paper – 510 C and press paper K‑Buff 0.1 mm to 1.0 mm are suitable for slot liners, wedges, and phase/barrier insulation in reactors and large machines.
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Filament Reinforced Paper Tape is applied as a binding and mechanical reinforcement tape over coils, joints, and terminations in power cables and windings.
Thermal and shielding applications
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Alutherm Paper and aluminium crepe papers combine thermal and electrical insulation with metallic shielding to control partial discharges and electrostatic fields.
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High‑elongation crepe structures maintain tight wrapping even under thermal cycling and mechanical vibration, reducing the risk of insulation loosening over time.
Example FAQs for website
1. What is crepe paper insulation?
Crepe paper insulation is an electrical‑grade cellulose paper that has been mechanically creped to increase elongation, flexibility, and surface area, making it ideal for insulating irregular shapes in transformers and cables. The creped structure enables better oil impregnation, higher mechanical strength, and improved resistance to tearing compared with flat insulation papers.
2. Where is Aluminium Crepe Paper – 90/135 used?
Aluminium Crepe Paper – 90/135 is typically used as shielding and insulation around leads and windings in high‑voltage transformers and instrument transformers. The aluminium layer provides electrostatic shielding while the creped paper ensures flexibility and dielectric performance in oil‑immersed environments.
3. What is the difference between crepe paper and press paper K‑Buff 0.1–1.0 mm?
Crepe paper is a flexible, crinkled insulation designed to follow tight bends and irregular contours, whereas press paper is a flat, more rigid insulation used for cylinders, spacers, and structural barriers. Many transformer designs combine both: crepe paper for leads and critical stress points, and K‑Buff presspaper for core/coil barriers and mechanical support.
4. Are SIDA crepe papers compatible with transformer oils?
Electrical‑grade crepe papers are made from high‑purity sulfate insulating pulp and are fully compatible with standard transformer mineral oils and many alternative insulating liquids. They are free from conductive particles and designed for rapid oil impregnation, which supports dielectric strength and long‑term reliability in service.
5. What thicknesses and crepe levels are available?
Standard crepe paper thickness typically ranges from 0.05 to 0.25 mm, with elongation levels from roughly 50% to more than 150% depending on grade and base weight. SIDA’s portfolio covers popular industry grades such as Crepe Paper – 67/100, 60/170, 60/90, Denission Crepe Paper – 35 HC, Crepe Paper – 22 HCC, and Crepe Paper – 510 C, as well as customised widths and roll lengths on request.
6. Which standards do these materials meet?
Crepe and presspaper insulation are manufactured to comply with major IEC and transformer standards used globally, including IEC 60554 for cellulosic papers and related specifications referenced in transformer standards. Customers can request documentation and test reports for dielectric strength, thickness, basis weight, crepe percentage, and tensile properties against required standards in their projects.
This content can be directly adapted into your product page sections (Overview, Specifications, Applications, Downloads, FAQs), with SIDA branding and exact values inserted once final internal data sheets are available.