Description
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What is Laminated Densified Wood Sheet?
Laminated densified wood (also known as electrical laminated wood or transformerwood) is an engineered insulation composite made by stacking thin wood veneers and bonding them with special insulating resins under high pressure and temperature.
This process creates a material that integrates the mechanical strength of wood fibers with the dielectric performance of insulating resins, resulting in a stable structural insulation material used in power equipment manufacturing.
Compared with traditional insulation materials, laminated densified wood provides:
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High compressive strength for structural support
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Excellent dielectric insulation performance
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Good compatibility with transformer oil
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Low density and lightweight structure
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Long-term dimensional stability
It is widely used in power transformers, distribution transformers, instrument transformers, and other high-voltage electrical equipment.
Key Features & Advantages
Excellent Electrical Insulation
The material exhibits high dielectric strength and stable insulation performance under high voltage conditions.
High Mechanical Strength
Multi-layer veneer structure provides excellent compressive, tensile, and bending strength.
Superior Oil Compatibility
Designed for oil-immersed transformer environments with excellent transformer oil absorption capability.
Low Density & Lightweight
Compared with metal structural components, laminated wood significantly reduces transformer weight and cost.
Thermal Stability
Suitable for long-term operation in transformer oil environments up to approximately 105–120°C.
Dimensional Stability
Low shrinkage and excellent structural integrity under pressure and temperature variations.
Easy Machining
The material can be easily processed into precision components such as rings, spacers, blocks, and structural parts.
Typical properties include good electrical insulation, high mechanical strength at low density, excellent oil absorption, and resistance to temperature and wear.
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Technical Data Tables
| NINGBO SIDA NEW MATERIAL CO.,LTD. | ||||||
| Test Report | ||||||
| Description of Products: Laminated wood Produces time:2026.01 | ||||||
| No. | Property | Unit | Normal Value | Test Result | Test Method | |
| 1 | Thickness shrinkage after drying | % | ≤1.5 | 1.2 | GB/T20634.1.2 | |
| 2 | Density | g/cm3 | 0.9-1.1 | 1.09 | ||
| 3 | Tensile strength | MD | MPa | ≥120 | 128 | |
| CMD | ≥108 | 125 | ||||
| 4 | Compressive strength | MD | MPa | ≥50 | 63 | |
| CMD | ≥120 | 135 | ||||
| 5 | Dielectric loss factor | 20 ℃ | % | ≤2 | 1.4 | |
| 90 ℃ | ≤10 | 8.8 | ||||
| 6 | Ultimate thickness expansion after oil immersion | % | ≤0.5 | 0.25 | ||
| 7 | Bond stregth | N | ≥2500 | 2865 | ||
| 8 | Oil absorption | % | ≥10 | 12.5 | ||
| 9 | Permittivity | 20 ℃ | / | ≤3 | 2.2 | |
| 90 ℃ | ≤3.6 | 2.7 | ||||
| 10 | Moisture content | % | ≤6.0 | 5.6 | ||
| 11 | Creepage strength along the surface |
20 ℃ | KV | ≥45 | 53 | |
| 90 ℃ | ≥35 | 46 | ||||
| 12 | Resisivity | THK3mm | Ω ·cm | ≥1.0*1012 | 3.2*1012 | |
| 13 | Breakdown voltage | 20 ℃ | MV/m | ≥9 | 10.5 | |
| 90 ℃ | ≥7 | 10 | ||||
| Test result: Pass | ||||||
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.
| Parallel | Parallel | Parallel | Crosswise | Crosswise | Crosswise | Tangential* | Tangential* | |||
|---|---|---|---|---|---|---|---|---|---|---|
| IEC 61061 | P1R | P4R | – | C2R | C4R | – | T2R | T4R | ||
| DIN 7707 | KP20212 | KP20214 | KP20218 | KP20222 | KP20224 | KP20228 | KP20242 | KP20244 | ||
| Mechanical Properties | Unit | Standard | ||||||||
| Specific weight | g / cm³ | IEC 61061 | 0,7-0,9 | 1,2-1,3 | 1,3-1,4 | 0,9-1,1 | 1,2-1,3 | 1,3-1,4 | 0,9-1,1 | 1,2-1,3 |
| Flexural strength I II |
N / mm² | DIN EN ISO 178 |
150 | 200 | 220 | 120 | 140 | 150 | 130 | 180 |
| Flexural strength I II |
PSI | DIN EN ISO 178 |
21.750 | 29.000 | 31.900 | 17.400 | 20.700 | 21.750 | 18.850 | 26.100 |
| Modulus of elasticity I |
N / mm² | DIN EN ISO 178 |
14.000 | 17.000 | 18.500 | 11.000 | 13.000 | 15.500 | 14.000 | 16.000 |
| Modulus of elasticity I |
PSI | DIN EN ISO 178 |
2,0×106 | 2,5×106 | 2,7×106 | 1,6×106 | 1,9×106 | 2,2×106 | 2,0×106 | 2,3×106 |
| Compressive strength I |
N / mm² | DIN EN ISO 604 |
100 | 130 | 180 | 200 | 240 | 270 | 130 | 160 |
| Compressive strength I |
PSI | DIN EN ISO 604 |
14.500 | 18.850 | 26.100 | 29.000 | 34.800 | 39.150 | 18.850 | 23.200 |
| Compressive strength II |
N / mm² | DIN EN ISO 604 |
55 | 100 | 170 | 70 | 90 | 180 | 80 | 110 |
| Compressive strength II |
PSI | DIN EN ISO 604 |
7.900 | 14.500 | 24.650 | 10.150 | 13.050 | 24.100 | 11.600 | 15.950 |
| Tensile strength II |
N / mm² | DIN EN ISO 527 |
120 | 170 | 185 | 80 | 100 | 100 | 110 | 150 |
| Tensile strength II |
PSI | DIN EN ISO 527 |
17.400 | 24.650 | 26.825 | 11.600 | 14.500 | 14.500 | 15.950 | 21.750 |
| Impact strength I |
kJ / m² | DIN EN ISO 179 |
46 | 56 | 40 | 33 | 37 | 15 | 40 | 52 |
| Impact strength II |
kJ / m² | DIN EN ISO 179 |
40 | 50 | 32 | 28 | 33 | 12 | 36 | 48 |
| Electrical properties | Unit | Standard | ||||||||
| Electrical strength at 20°C II |
kV/25 mm |
IEC 60 243 |
70 | 70 | 45 | 70 | 70 | 45 | 80 | 80 |
| Electrical strength at 90°C II |
V/25 mm |
IEC 60 243 |
70 | 70 | 32 | 70 | 70 | 32 | 70 | 70 |
| Insulation resistance after treatment | Ω cm | IEC 60 093 |
1012 | 1012 | 1011 | 1012 | 1012 | 1011 | 1012 | 1012 |
| Dielectric loss factor at 50Hz 20° C | tan δ | DIN 53 483 |
0,01 | 0,01 | 0,01 | 0,01 | 0,01 | 0,01 | 0,01 | 0,01 |
| Physical properties | Unit | Standard | ||||||||
| Oil absorption | % | IEC 61 061 |
30 | 10 | < 2 | 25 | 10 | < 2 | 25 | 10 |
| Thermal conductivity at 20° C | W / mK | DIN 52 612 |
0,2 | 0,2 | 0,3 | 0,2 | 0,2 | 0,3 | 0,2 | 0,2 |
| Operating temperature continuous | ° C | – | 105 | 105 | 90 | 105 | 105 | 90 | 105 | 105 |
| Temperature limit for drying and impregnating | ° C | – | 140 | 130 | 100 | 140 | 130 | 100 | 140 | 130 |
Standard Dimensions
| Thickness | Width | Length |
|---|---|---|
| 8 – 120 mm | up to 1500 mm | up to 3000 mm |
| Custom sizes available |
Common sheet sizes:
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1000 × 1500 mm
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1000 × 2000 mm
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1500 × 2000 mm
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2000 × 3000 mm
Custom machining services are available.
Material Grades (Typical IEC Designations)
| Grade | Structure | Description |
|---|---|---|
| KP2022 | Parallel laminated | High mechanical strength |
| KP2024 | Cross laminated | Improved dimensional stability |
| KP2026 | Tangential laminated | Ring and curved structures |
Manufacturing Process
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High-quality wood veneer selection (Beech / Birch)
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Insulating resin impregnation
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Layer stacking
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High temperature and high pressure pressing
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Controlled curing
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Precision cutting and sanding
This process ensures high mechanical strength, stable insulation performance, and uniform density distribution.
Application Scenarios
Transformer Manufacturing
Laminated densified wood is widely used in oil-immersed transformers and instrument transformers for structural insulation components.
Typical transformer components include:
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Pressure plates
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Clamping rings
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Coil support rings
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Spacer blocks
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Insulation blocks
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Step blocks
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Support beams
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Lead support structures
Electrical Equipment
Used in various electrical insulation applications:
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Switchgear insulation structures
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High-voltage equipment
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Generator insulation supports
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Reactor insulation structures
Power Industry
Ideal for:
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Power transformers
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Distribution transformers
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HV electrical systems
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Electrical insulating components
Compliance & Testing Standards
Our laminated densified wood sheets comply with major international electrical insulation standards:
| Standard | Description |
|---|---|
| IEC 61061 | Densified laminated wood for electrical purposes |
| IEC 60243 | Dielectric strength testing |
| IEC 60093 | Volume resistivity testing |
| ISO 9001 | Quality management system |
| GB/T 20634 | Electrical laminated wood standard |
IEC 61061 specifically defines requirements for densified laminated wood sheets used in electrical insulation systems, including mechanical, electrical, and dimensional specifications.
Custom Machining Capabilities
SIDA also provides precision machining services for laminated wood components including:
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Transformer clamping rings
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Insulation spacers
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Structural blocks
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Customized insulation supports
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CNC machined transformer parts
Components can be produced according to customer drawings and technical specifications.
Frequently Asked Questions
1. What is laminated densified wood used for?
It is mainly used as structural insulation material in transformers, switchgear, and high-voltage electrical equipment.
2. Is laminated wood compatible with transformer oil?
Yes. Laminated densified wood has excellent compatibility with transformer oil and maintains stable performance in oil-immersed environments.
3. What standards does the material comply with?
Most transformer laminated wood materials comply with IEC 61061 standards for electrical laminated wood.
4. Can laminated wood replace metal parts in transformers?
Yes. Due to its high strength and low density, laminated wood can replace certain steel or composite components, reducing transformer weight and cost.
5. Can you provide customized sizes?
Yes. SIDA provides customized sheets, blocks, and machined insulation parts according to customer drawings.