Views:76 Author:Site Editor Publish Time: 2020-08-25 Origin:Site
Table of Contents:
Chapter Three Performance characteristics of extruded board
High compressive strength (compressive resistance 100-1000KPA)
Excellent thermal insulation performance and long-lasting (thermal conductivity up to 0.028W/M·K)
Hydrophobic and moisture-proof (water absorption rate <1%)
Good dimensional stability, weather resistance (30-50 years of life)
The thermal conductivity of the cell wall, the thermal conductivity of the gas in the bubble, the radiation penetration rate of the cell wall and the bubble, and the convective thermal conductivity of the gas in the bubble. The second factor accounts for the largest proportion, about 60%.
Over 99%, the closed-cell ratio of foamed polyurethane (insulation material) is 80%.
Floor heating varies according to the usage scenarios, so the density requirements are different. The density of extruded board for floor heating is generally about 35KG/m³, the density of extruded board for wall insulation is about 25KG/m³, and the density of extruded board for filling is about 45KG/m³.
2cm extruded board can be equivalent to 100cm concrete and 120cm cement perlite.
The compressive strength of the extruded board is directly proportional to the density, the greater the density, the greater the compressive strength. According to different parameters such as density, it can be controlled at 100-1000KPA. The extruded board made of high-quality raw materials is 35KG/m³, and its compression resistance can be 250-300KPA.
Due to the process, the compression strength of the extruded board is very low when it is just off the assembly line. As time increases, aging will increase the compressive strength, and then it will become stable. The general inspection is after 45 days of storage.
The water absorption rate is ≤1.5%v/v, and the moisture permeability coefficient is ≤3.5Ng/(m.sPa), which makes the extruded board difficult to decompose and mildew.
Under the same other conditions, the density within a certain range is proportional to the compressive strength.
Different standards have different classification methods, and the commonly used combustion properties of extruded boards are divided into B1, B2, and B3. B1 is non-flammable (oxygen index greater than 30%), B2 is flammable (oxygen index greater than 26%), and B3 is flammable.
The environmental protection of extruded boards depends on the raw materials and flame retardants. The recycled raw materials easily contain harmful substances such as free benzene, styrene, TVOC, etc., and the flame retardant HBCD is not environmentally friendly.
The long-term thermal resistance value of the extruded board, like other polymer foam materials, will also change over time. This phenomenon is called "curing".
Floor heating specifications: 1670*600*20mm, 1670*600*30mm, etc.
Specification for building insulation: 2000*600*200mm, 2000*600*30mm, etc.
Because the extruded board is continuously extruded, the length can be customized, and the width can only be 600mm before, but now it can be 1200mm with technological advancement. As for the thickness of the thinnest 10mm, the thickness can be up to 100mm.
The dimensional stability of the extruded board at high temperature (70℃) and low temperature (-20℃) is very good, and it can be controlled within 1%.
The indicators are: after 300 freeze-thaw cycles, the compressive strength of the extruded board will not exceed 10% of the initial value; the long-term water absorption rate for building insulation does not exceed 2%; the long-term water absorption rate for civil engineering does not exceed 5%.
Physical properties: apparent density, true density, dimensional stability, water absorption, water vapor transmission coefficient, freeze-thaw cycle;
Mechanical properties: compression performance, bending performance, shear strength, compression creep, tensile strength;
Thermal performance: thermal conductivity, thermal resistance, long-term thermal resistance;
Combustion performance: limit oxygen index, combustion performance classification, smoke density.
Raw material properties and production process: uniform cells, small gaps, and good foaming agent performance are beneficial to reduce thermal conductivity.
Apparent density: The thermal conductivity of density in a certain range is inversely proportional, and after reaching the optimal density, it is proportional to a certain range.
Cell size: When the apparent density is the same, the smaller the cell size, the smaller the thermal conductivity.
Placement time: The thermal conductivity of the extruded board increases rapidly within 30 days after it is off-line, and stabilizes after 90 days.
Humidity: Thermal conductivity increases after XPS absorbs water.
Temperature: Due to the influence of radiation heat transfer, the thermal conductivity increases with increasing temperature.
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