In recent years, my country has become one of the fastest-growing countries in the construction industry in the world. It is expected that my country will account for 29% of the global insulation materials market in 2014. At present, my country is the country with the largest demand for insulation materials in the world.
According to Zhao Honghan, a member of the Science and Technology Development and Advisory Committee of the China Composite Materials Society, insulation materials for construction can be roughly divided into inorganic and organic types. Commonly used inorganic external insulation materials for external walls include rock wool, perlite, foamed cement (concrete), foamed glass, and vitrified microbeads. Although they have good fire resistance, the thermal conductivity is high and the thickness is inevitable Increase, increase construction load and construction cost. Organic exterior wall insulation materials include polystyrene foam (PS, divided into EPS and XPS), polyurethane foam (PU) and phenolic foam (PF), etc. It has the advantages of low density, low thermal conductivity and easy construction. The combustion grade of EPS and XPS is B2 grade (flammable). When heated above 80℃, it will melt and soften, shrink and drip. After fire, the thick smoke will roll and produce poisonous gas. The PU combustion level is also B2 level. Although the softening temperature is slightly higher (110°C) and there is no melt dripping, the smoke and poisonous gas generated after the fire is very harmful.
In the 1980s, foreign scientists studied phenolic resins and their products and found that they have outstanding flame retardant, smokeless, and non-toxic properties (referred to as FST characteristics). The phenolic foam made is more flame-retardant than polystyrene Thin foam and polyurethane foam are better. A PF plate with a thickness of only 30 mm was subjected to flame spraying at 1700°C for 10 minutes. It was only slightly charred on the surface but could not burn through, neither igniting nor emitting dense smoke and poisonous gas.
It is understood that since the 1990s, phenolic composite materials, including PF, have been greatly developed. First of all, they have been valued by the military forces of Britain, the United States and other countries, and they are used in the aerospace and defense military industries. Later, PF was used in places with strict fire protection requirements, such as ships, stations, and oil wells, and was gradually pushed into public and civil construction fields such as hospitals, sports facilities, and building housing. Due to its low thermal conductivity, PF has about twice the energy-saving insulation performance compared with traditional insulation materials such as rock mineral wool, glass wool and expanded perlite. It is recognized that its energy-saving insulation performance ranks first among all insulation materials, and some people call it the "king of insulation" or the third-generation insulation material. For example, the thickness of the expanded perlite insulation layer needs to be 60mm, while PF only needs 25mm to achieve the same insulation effect.
In recent years, major fire accidents have occurred in my country, and the analysis of the main cause of the fire has a great relationship with the use of flammable materials. The high-efficiency, normal-temperature foaming phenolic resin and special curing agent developed, developed and produced by the Phenolic Technology Center of Jinan University do not require heating, that is, they can be foamed and cured at a relatively low temperature (above -5℃). The process is simple, not only can be produced in the factory, but also can be carried out on-site construction and field operations, has now become China's new generation of highly efficient insulation materials. This heat insulation material is the first field heat insulation operation in China. It has been used in the heat insulation projects of Yankuang Group, Shandong Electric Power, Jinan Steel Plant, Zhongyuan Oilfield, East China Petroleum Administration and other units, and has achieved good economic and social benefits.
On this basis, the phenolic technology center of Jinan University adopts advanced production technology, that is, continuous production technology is used to replace backward intermittent production technology. In October 2002, PF foam composite board was the first to achieve continuous production in China. The product was successfully applied to the central air conditioning and ventilation system, and was well received by HVAC design experts and businesses. In 2004, phenolic resin production technology and continuous foaming composite technology passed the national building materials new product and new technology appraisal. In 2005, phenolic resin production technology and continuous foaming composite technology won the second prize of National Building Materials Science and Technology Progress Award. The evaluation given by the experts is: the production technology of phenolic resin and continuous foaming composite technology have reached the domestic leading level and the international advanced level; the products meet the relevant standards of enterprises and countries. The ventilation duct made with this product has the characteristics of heat insulation and durability, light weight and energy saving, beautiful and clean, fireproof and waterproof, simple and labor-saving, and all performance indicators are in line with relevant industry and national standards and specifications. At present, the product has been used in Beijing subway transformation, new construction (Metro Line 5, Line 10, Olympic feeder, etc.), water cubes and other sports venues, as well as convention and exhibition centers, shopping malls, supermarkets, hospitals, schools and old residential buildings Renovation of HVAC systems in public facilities.
Although the current PF produced in China has a certain gap in process technology and construction application compared with foreign countries, in terms of improving fire performance, there are already three composite PF boards developed by three domestic companies that have passed the national fire protection building material quality supervision The inspection center's inspection shows that its combustion performance reaches GB 8624A level. In particular, it is worth noting that in recent years, relevant scientific research units and enterprises in China have made new breakthroughs in phenolic resin modification and foaming technology. One is to overcome the shortcomings of PF powdering slag, high brittleness and low strength; The second is that the cost of PF continues to decrease, which is closer to PS; the third is that the pH value of the product is close to neutral and non-corrosive to metals.
Under the existing comprehensive strength, the efficiency of the external insulation material of the external wall is difficult to achieve both. Is it necessary to take into account the energy-saving insulation of the building, or is it completely inclined to eliminate the hidden dangers of fire? In this debate, which material can occupy the absolute advantage in the insulation system of the external wall of the building, it is still impossible to draw a conclusion. According to Hu Xiaoyuan, executive vice chairman of the China Thermal Insulation and Energy Conservation Materials Association, the current research focus on inorganic insulation materials should focus on reducing energy consumption during production, limiting dust and fiber emissions, and reducing the amount of binder. The research focus of organic thermal insulation materials should be on finding more suitable blowing agents, improving the flame retardant properties of the materials and reducing the production costs of the materials.