【 Weak current college 】 building polyurethane insulation performance analysis---Power By 【 China power house network 】

Construction with polyurethane rigid foam insulation material is polyurethane industry is an important branch, it features a wood use with thermal insulation, waterproofing, etc. Such products since the 1960s in the European construction industry since the application has a 40-year history, some countries have adopted legislation to polyurethane as construction specified insulation waterproof materials. In recent years, as China's building energy market is developing rapidly, rigid polyurethane foam insulation products in building insulation waterproof areas has been widely used, has become the leading market for insulation products.

Pu (polyurethane, the English abbreviation PU) is on a primary key in the polymer contains many duplicate — NHCOO — groups of high-molecular compounds. Polyurethane series products is normally provided by dual or multiple organic isocyanate and polyol in a variety of additives, after polymerization of polymer compounds, two main materials are only included in to two or less-functional groups, polymerization of a linear structure of the compounds, if one or both of the main materials, parts or all of three or more functional groups, you can get-sized structure of polymers, polymer structure, the performance difference is very big. Just like steel, although are iron-carbon alloys, iron carbon ratio is different, the heat treatment process, distinct from its performance. Polyurethane raw materials in a wide range of industry applications, due to the application of industry characteristics and the production of products, the industry as the main raw material for polyurethane combinations of materials performance requirements are also different. Take the double function of waterproof insulation rigid polyurethane foam (SPF) is also completely different from those used to refrigerators, cold storage only play the role of polyurethane insulation (PUR), although they look very similar to the structure looks like, but as a building material, the integration of insulated waterproof polyurethane hard foam to break the traditional building materials feature a single, waterproof and thermal insulation, thermal insulation of not not waterproof, waterproof in case of leakage, insulation layer immediately lose heat insulation features of defects. And other single-function insulation or waterproof material compared to polyurethane rigid foam provides significant advantages:

1. rigid polyurethane foam with a material more functionality with insulation, waterproofing, noise, vibration, and many other functions;

2. insulation performance excellence, is all in the lowest thermal conductivity of building materials (≤ 0.024, green-free foaming technology), the highest thermal resistance of insulation, thermal conductivity of only EPS foam polystyrene plates;

3. the rigid polyurethane foam with continuous dense surface and near-100% percent of high-intensity Internet wall obturator, has the perfect impermeability. Use spray method to achieve seamless waterproof insulation continuous, seamless roof and external wall insulation shell, excellent impermeability waterproofing;

4. strong self-adhesive able (without any intermediate bonding materials), and a solid roof and facade bond, wind resistance and resistance to negative air pressure mortgage good performance;

5. overall spray, complete elimination of the "hot spot" and "cold";

6. flexible gradient technology can effectively prevent waterprooflayers;

7. at the mechanized operations, Automatic batching, quality first, the construction of fast cycle time is short;

8. chemical stability, long life, on the surrounding environment does not constitute pollution;

9. from the open fire self-extinguished and burning only carbonized not dripping drips, carbonized layer dimensions and appearance is essentially the same, can effectively cut off air, prevent the spread of the fire safety performance is good.
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Polyurethane rigid foam material itself merits of performance, the security of buildings, insulation, water has a significant impact in the selection must be attention.

Construction with polyurethane rigid foam insulation and waterproofing of cold storage, refrigerator with polyurethane rigid foam insulation performance of great difference, mainly reflected in fracture elongation rate, closed-cell, size variation, adhesive strength on four key performance indicators.

Difference: fracture elongation

Fracture elongation rate is a measure of rigid polyurethane foam resistant to stress not produced permanent deformation of the key performance indicators, and only play the role of non-waterproof insulation features of freezer refrigerator with polyurethane rigid foam on this key performance indicator and no requirements.

National building material industry standards (JC/T998-2006) clearly states: polyurethane rigid foam if used as roof and wall insulation material is waterproof, must meet the elongation rate of more than 10% of the basic requirements in order to guarantee the use of ambient temperature changes, roof and wall shrinkage and swelling, severe frost and building foundations caused by non-uniform settlement of waterproofing layer fault, drum and cracking. The rigid polyurethane foam insulation features in play excellent, fully demonstrate its reliable waterproof function, only the extension rate above the national industry standard rigid polyurethane foam to ensure that buildings warm in winter and cool in summer and comfortable roof leak, the outer wall of permanently without damp.

Difference between the two: dimensional change rate

Polyurethane rigid foam affected by ambient temperature changes, the size and volume of some changes occur to the size of the dimensional change rate and the type of raw materials, foam structure, core material density molding process and the types of foam and many other factors, hightemperature performance is better in rigid polyurethane foam in-20 ° c to + 80 ° c ambient temperature, the size should not be a significant change. Rigid polyurethane foam with closed-cell rate was 95% percent of the holes in the foam closed gas pressure with the ambient temperature changes, if the bubble-walled structural strength is relatively small, foam dimensions are due to the pressure of gases in closed cells change produces high temperature low temperature shrinkage or expansion of deformation, the size is relative deformation (i.e. size change rate), the greater the polyurethane waterproof insulation produces the probability of fracture or opening.

Used for construction of polyurethane rigid foam according to the national industry standard JC/T998-2006, the dimensions change rate should be ≤ 1%, to fit the building in the summer and the cold season because of the dramatic change day and night temperature differenceIn the result of external finishes system font size is too large for contraction and expansion. Dimensional stability is clear and external finishes system security is closely related to the use of, the higher the value, security and more poor, size variation rate is greater than 1% of% of rigid polyurethane foam is not consistent with the national building materials industry standards.

Difference between the rate of three: obturator

Obturator rate is a measure of material absorption and an important indicator of thermal conductivity, low rate of hard closed-cell foam absorption and higher thermal conductivity, thermal insulation features of the material and thawing resistance has a critical impact. Building with rigid polyurethane foam used as roofing insulation materials in use, its foam obturator rate should be at least higher than 95% percent, when the obturator rates below 70%%, short-time rain and no roof leakage, but in many days consecutive rainy seasons, because of the rigid foam long immersion in water, the water absorption in perforated foam, infiltration of rainwater in the bubble, in the role of gravity hole through chain, and grass-roots level into the roof was hold at the grass-roots and rigid foam, even for the best, in the hot sun exposure in the short term it is also difficult to undergo rigid foam insulation and cover up. On the contrary, because of the roof by sunlight, upper and lower temperature high low temperature, moisture migration to the lower roof instead, causing rain does not leak, sunny anomaly of leakage, this phenomenon in the South, particularly huangmei season.

Difference between four: tensile strength and self adhesive strength

Polyurethane rigid foam exterior insulation system's overall strength depends on polyurethane base metal tensile strength (System strength weakest link), rigid polyurethane foam itself tensile strength is in fact the entire external finishes drawing strength of the system. For example: the tensile strength of rigid polyurethane foam, the whole wall is 200kpa system is resistant to pulling strength; if this index 200kpa declined to 100kpa, the entire exterior wall systems-pulling strength will be reduced to half, safety factors are bound to dip into the original half.

In addition, the building industry with sprayed polyurethane rigid foam in material preparation time should also be adequately considered external wall insulation systems for use in bonding strength requirements, therefore requires its metal, concrete, masonry, wood, glass and other materials with excellent self adhesive properties. National building material industry standard JC/T998-2006 and, more recently, in the rigid polyurethane foam exterior insulation engineering and technical guidelines, the rigid polyurethane foam for auto-adhesive strength provides for mandatory targets, which is sprayed polyurethane rigid foam, relative to the foamed polystyrene (EPS) and extruded insulation Board (XPS) exterior insulation system security has the clear advantage of a key indicator. It is worth mentioning that strength is rigid polyurethane foam is the most important mechanical properties, it directly determines the external finishes system of wind resistance, impact resistance, resistance to strain the capacity and the ability to host the total weight is to assess external wall insulation system using the security of the most important and most direct performance indicators.

To sum up, the user selects the rigid polyurethane foam as a building insulation waterproofing RGD material use, you must press the national building materials industry standard JC/T998-2006 requirements on the material density, strength and fracture elongation, dimensional stability and obturator rate for strict identification. As is currently the only integration of new building materials and insulation waterproof, rigid polyurethane foam heat insulation material in the application of domestic construction industry is still in its initial phase. Fortunately, to speed up the building insulation materials innovation, promotion of rigid polyurethane foam in the field of energy efficiency in buildings, construction of application also specially established "polyurethane building energy-saving application promotion working group", in a high degree of attention of the Ministry of construction and full promotion, rigid polyurethane foam insulation and waterproofing materials in domestic energy industry has made substantial progress.