Research on the Status Quo of New Energy-saving Insulation Materials and Flame Retardant Technology

0Overview In recent years, with the steady growth of the domestic economy and the development of science and technology, the trend of large-scale, centralized, three-dimensional, special structure and complicated equipment has been promoted, but compared with many developed countries at the same latitude. The insulation performance of the house is much worse. At present, the exterior wall materials of most buildings in China are mainly reinforced concrete and solid clay bricks. The thermal conductivity of the wall is high, and the room temperature rises after being exposed to the sun. Therefore, the development of new insulation wall materials is not only promising, but also imperative. At present, roofing and wall insulation materials have good thermal insulation and energy saving effects, but theoretical research on product development and flame retardant technology of fire retardant coatings and flame retardant materials.

The fire retardant performance of the fire is poor, and sometimes cracking, hollowing, and falling off problems occur. In addition to thermal insulation properties, thermal insulation wall materials also need to have fire retardant properties.

The lessons of CCTV's new site fire accidents are very painful. The preliminary site survey results show that after the fire in the north of the CCTV new site, the combustion is mainly concentrated on the insulation layer material under the titanium alloy. This material has poor fire retardant performance and has a superficial skin. The characteristics of burning and spreading are extremely fast. So it instantly spread from the top of the North Building to the entire building. At present, this new type of material is used in many buildings in Beijing and the whole country. This is also the case with the fire at Peking University Table Tennis Hall and the fire of Shenyang Dynasty Wanxin International Building. In view of this, it is imperative to carry out research on new energy-saving heat-insulating materials, to meet the country's demand for energy-saving insulation and fire-retardant materials. It is imperative to vigorously develop and promote the application of thermal insulation technology and materials.

1 Research status and development trend of energy-saving insulation materials at home and abroad In 1975, the United States first issued the ASHRAE (American Heating, Refrigeration and Air Conditioning Engineering Association) standard 90-75 new building design energy saving. Based on this, in December 1977, the government officially promulgated energy conservation regulations in the structure of new buildings, and received significant energy savings in 45 states. The National Energy Administration, the Bureau of Standards, and the National Conference on Building Codes and Standards continue to propose new content in building energy efficiency design, and the ASHRAE standard is revised every five years. Since the implementation of the first energy-saving standard in the United States until 2011, the United States has added an additional 43 billion US dollars.

The Japanese residential finance public bank, as early as 1979, promulgated the thermal insulation standards for residential buildings, which stipulated the thermal resistance of the building and set a minimum limit for the various insulation materials used. Denmark's heating area increased by 30% in 1985 compared to 1972, but heating energy consumption decreased by 3.18 million tons of standard coal, and the proportion of heating energy consumption to total national energy consumption also dropped from 39% to 28%. This shows that abroad The building energy efficiency regulations have achieved significant social and economic benefits over the past 30 years.

The heat transfer per unit area of ​​wall, roof and door and window in China is 2~5 times that of developed countries with similar climatic conditions, and the energy consumption of buildings is extremely serious. In Europe, the heating energy consumption of new homes has dropped to 1/4~1/6 in the 1970s. In recent years, Germany has also proposed the concept of “zero energy consumption”. At present, China's building energy consumption accounts for about 27% of total social energy consumption, and building energy application efficiency is only about 1/3 of that of developed countries. Most of China's long-term architectural design standards are based on the low standards since the 1950s. The insulation performance of the building envelopes is poor, resulting in low energy efficiency of buildings, resulting in great energy waste. It is necessary to use new wall insulation materials. Therefore, the development of new insulation wall materials is not only promising, but also imperative.

China's thermal insulation wall materials, such as aerated concrete, gypsum board, gypsum hollow slabs, gypsum board, hollow blocks, hollow bricks, have achieved certain energy-saving benefits. In recent years, a variety of lightweight slab materials and structures have been developed, such as GRC panels, polystyrene sandwich panels, color steel foam sandwich panels, rock wool and glass sandwich panels, etc., which have their own characteristics through application, but mainly The problem is that the price is high. At the same time, there are also poor fireproof grades, large moisture absorption, moisture absorption, structural design and construction specifications, which are difficult to promote. At present, the roof insulation is still made of traditional cement expanded perlite, aerated concrete blocks and slag. There are also organic foam insulation such as polystyrene board, but the fire rating is low, and roof leakage is also a difficult problem. In recent years, residential energy-saving demonstration communities in Beijing and other cities have used water-swelled perlite and silicate composite thermal insulation coatings for wall and roof insulation to achieve better use and energy-saving effects. At present, the research, production and use of a wide range of thermal insulation wall materials can be mainly divided into the following categories: (1) Expanded polystyrene board thin plastering exterior wall thermal insulation system expansion polystyrene board thin plastering exterior insulation system Beijing took the lead in promoting its application and quickly promoted it to Tianjin, Hebei, and Northeast China, as well as some southern provinces such as Shanghai, Jiangsu, and Hunan. It is one of the faster systems for the promotion of thermal insulation and energy conservation projects in China. The insulation material used is mainly polystyrene foam board, and the auxiliary materials include special expansion mushroom anchor, alkali-resistant glass fiber mesh, polymer bonding mortar, plastering mortar, exterior wall coating or decorative tile. The construction method is to use a polymer bonding mortar to adhere the polystyrene foam board to the wall body, riveting with a special expanded mushroom anchor nail, and sticking the alkali-resistant glass fiber mesh cloth with the anti-seepage cracking mortar to the polystyrene foam. On the board, then apply anti-seepage cracking mortar, brush exterior paint or make tile decoration. The advantages are: heat preservation and energy saving efficiency, and the construction is relatively standardized; the disadvantages are: poor fire performance, complicated process, high requirements on the flatness of the base wall, high engineering cost (70~90 yuan/m), heat preservation The degree of firmness and service life of the layer are poor. In engineering applications, the bonding is not strong, the cracking of the surface is anti-seepage and cracking, and the large-area cracking, hollowing, falling off, etc., especially when the decorative layer is a tile, it is particularly serious. There are many phenomena in which the tiles and the insulation layer fall off in a large area.

(2) Adhesive powder polystyrene granule external wall thermal insulation system The rubber polystyrene granule external wall thermal insulation system is a main material used for the internal and external thermal insulation of the external wall after the expanded perlite thermal insulation material, both in the south and in the north. Popularized and applied, it has a large application in Jiangsu, Anhui, Jiangxi, Hunan, Hubei and other provinces. Its main insulation material is polystyrene particles, and the auxiliary materials are polymer rubber powder, alkali-resistant glass fiber mesh cloth, expanded mushroom anchor and the like. The construction method is to pre-mix the polyphenyl granules and the polymer rubber powder into a slurry, uniformly smearing the wall, and then sticking the alkali-resistant glass fiber mesh cloth after the drying, wiping the anti-seepage cracking mortar, and then brushing Exterior wall or tile finishes, tile facings must be secured with galvanized steel mesh and expanded mushroom anchors. The advantages are as follows: the heat preservation effect is good, the insulation layer and the wall are easy to be bonded, and the flatness of the base wall is not high, the construction process is simple, the construction cost is low, and the large area cracks, hollow drums, and fall off are generally not reproduced. The problem is technically feasible. Since the slurry after mixing is as easy as powdering traditional cement mortar and the bonding strength is very good, it is easy to popularize. The disadvantages are: poor fire resistance, but thinner than expanded polystyrene board. The plastering system is better. The main technical contradiction between the thermal insulation effect of the rubber polystyrene particle insulation system and the strength of the thermal insulation layer is that the more polyphenylene granule content in the thermal insulation slurry, the smaller the cement rubber powder content, the lower the strength of the thermal insulation layer, and the thermal insulation. The better the energy saving effect is; if the content of the cement glue powder in the heat preservation slurry is more, the content of the polyphenyl granule material is smaller, the strength of the heat insulation layer is higher, and the heat preservation effect is worse. Therefore, the material ratio of the rubber powder polystyrene granule insulation system must be strictly in accordance with the requirements and preparation of the G158-2004 rubber powder polystyrene granule external wall insulation system to ensure the insulation and energy saving effect of the system; secondly, it should be noted during construction. Detailed processing, such as the reservation of wall expansion joints, the lap joint of alkali-resistant glass fiber mesh or galvanized steel mesh and the number of expanded mushroom anchors and the length of anchor bolts, etc., should be paid attention to during construction to ensure the whole The system is safe, stable and long-term use.

(3) Inorganic thermal insulation mortar (or vitrified microbead insulation mortar) system inorganic thermal insulation mortar (or vitrified microbead insulation mortar) system is a new type of thermal insulation material, the thermal insulation material uses inorganic hollow vitrified microbeads, with polymer The advantages of the high-density integrated micro-hollow thermal insulation system are: 1 because the vitrified microbeads are inorganic materials, and the fireproof performance is good; 2 the compressive strength and the compressive shear bond strength are high; 3 the weather resistance is good , dry shrinkage is small, no mesh cloth; 4 simple construction, low engineering cost. Disadvantages are: inorganic vitrified microbeads have higher thermal conductivity due to their higher density, and the thermal insulation effect is also poor. In order to achieve the same thermal insulation and energy saving effect as the rubber polystyrene particles, the general measures are thickening. The thickness of the insulation layer, thus increasing the self-gravity, affects the stability of the long-term safe use of the insulation system, so when the energy-saving requirements reach 50% to 65%, the insulation system should not be used, and it does not meet the required requirements. energy saving effect.

(4) Commonly used thermal insulation materials Rock (mineral) cotton and glass wool are collectively referred to as mineral wool and are inorganic materials. Rock wool does not burn, the price is lower, it also has a certain sound insulation effect while satisfying the thermal insulation performance, but the quality difference is very different, the insulation performance is good, the density is low, the tensile strength is low, and the durability is poor. . Glass wool feels better than rock wool and can improve workers' working conditions, but at a higher price. Styrofoam is made of polystyrene resin as the main raw material and foamed by foaming agent. It has numerous closed micropores inside, which has small apparent density, low thermal conductivity, low water absorption and sound insulation. Good performance, high mechanical strength, high dimensional accuracy and uniform structure, so it is widely used in exterior wall insulation. Rigid polyurethane foams have superior thermal insulation properties and low thermal conductivity, which is not comparable to other materials. At the same time, its unique closed-cell structure has superior water vapor resistance, does not require additional insulation and moisture, and simplifies the construction process, but because of its high price and flammability, it limits its widespread use.

In general, the development of new insulation materials is not only promising, but also imperative. At present, the thermal insulation wall materials studied at home and abroad are developing towards light weight, high performance (high efficiency fire retardant function and reliability, durability), inorganicization, simple construction and installation, and green environmental protection.

2 Research and application of flame retardant technology for new energy-saving insulation materials Currently, the most widely used exterior insulation materials expose some problems, the most prominent of which is fire performance. Typical cases of fires caused by exterior insulation materials such as CCTV's new site, the Cultural Center of the Park, 29 major fire accidents, and Peking University table tennis stadium fires. Therefore, the fire hazard of insulation materials has attracted the attention and attention of the public and has become a key technology for the sustainable development of insulation materials. To this end, the Fire Department of the Ministry of Public Security issued a research task on the flame retardant technology of new energy-saving insulation materials to the Sichuan Fire Research Institute of the Ministry of Public Security in 2009. On the basis of fully investigating the existing technology of external thermal insulation materials, the research team comprehensively considers economy, reliability and practicability. After more than two years of work, it has developed a slurry that is easy to apply and suitable for external thermal insulation. Type energy-saving insulation flame retardant material.

2.1 Research on thermal insulation inorganic light collection materials Generally, the thermal conductivity of silicate composite thermal insulation mortars tends to increase with increasing density. Therefore, the function of the thermal insulation material is achieved by the core composition of an inorganic light aggregate. At present, the inorganic light aggregates on the market include open-cell expanded perlite, closed-cell expanded perlite, vitrified micro-beads, expanded vermiculite, pottery sand, and the like. Among them, ceramic sand (generally refers to fine particles less than 5mm in ceramsite), even for ultra-light density ceramsite, its density is less than 300kg/m3, which is larger than other light aggregates, and the thermal conductivity is naturally larger. Although the insulation layer can also meet the insulation design requirements, it also increases the load of the structure itself, and the cost increases. Therefore, the use of ceramic sand as a thermal insulation material has been limited. Because of the high water absorption of the expanded vermiculite, the equilibrium moisture content of the final product is higher, and the thermal conductivity of water is much larger than the thermal conductivity of air, resulting in a corresponding increase in the thermal conductivity of the final product. Therefore, it is also used as a thermal insulation material. Subject to certain restrictions.

In the research of this project, after preliminary screening work, the core of the thermal insulation system consists of an inorganic light aggregate, which is determined to be expanded perlite and vitrified micro-beads with small thermal conductivity. Among them, expanded perlite is divided into traditional open-cell expansion. Perlite and spherical closed-cell expanded perlite.

2.2 Research on modification of binders In addition to thermal insulation, sound insulation, fire retardant and good physical and chemical properties, energy-saving and heat-insulating fire-retardant materials are also required to not burst and crack at high temperatures. It has the characteristics of weather resistance, water resistance, simple construction and strong adhesion. Therefore, the binder used in energy-saving heat-insulating fire-retardant materials is one of the key components.

In order to maintain the strength and structural integrity of the energy-saving heat-insulating fire-retardant material in fire or high temperature, the selected binder should be a cementing material that can be converted into a high-temperature resistant material at a high temperature or a sintered material that can be sintered. The main gelling material of the energy-saving heat-insulating flame-retardant slurry system is ordinary Portland cement, which has certain defects in bonding strength, crack resistance, water resistance and weather resistance. Therefore, it must be modified by adding an auxiliary adhesive.

In the research, we used inorganic flame retardant elements in the molecular structure of the adhesive to impart good flame retardant properties. In addition, several binders were combined or reacted to form a composite binder, which gave the material a good comprehensive performance. Synthetic binders can be used to achieve the desired purpose by taking advantage of the advantages of long complement, good leveling and good toughness after film formation. The auxiliary adhesive for the fire retardant material is a silicone modified polyacrylate emulsion to improve the weather resistance of the binder and the adhesion and flame retardancy at high temperatures. The polyacrylic acid emulsion main chain is composed of C+C bond, and the side chain is a polar group such as a carboxylate group. This structural feature gives it the advantages of strong adhesion, oxidation resistance, weather resistance and oil resistance, and its main disadvantages. Stain resistance, water resistance and moisture permeability are poor. The polyorganosiloxane (referred to as silicone) main chain Si-O-Si is an inorganic structure, and the side chain is an organic group such as CH3, and thus is a typical semi-inorganic semi-organic polymer. Polyorganosiloxane has high Si-O bond energy, low internal rotation energy barrier, large molecular molar volume and small surface energy, which leads to its excellent high and low temperature resistance, water resistance, electrical insulation, chemical resistance and high performance. Flame retardant. The modification of acrylate with silicone can combine the advantages of both to improve the properties of acrylate "hot-sticky crispy", weathering, water resistance and high temperature resistance, and improve the mechanical properties of the film-forming material. We use a copolymerization method in which other groups such as silicone are introduced into the molecular structure of the acrylic emulsion to improve the compatibility of the polysiloxane and the polyacrylate, inhibit the surface migration of the silicone molecules, and uniformly disperse the two, thereby improving the aggregation. The purpose of physical and mechanical properties of acrylate emulsions. The researched new energy-saving thermal insulation fire-retardant materials not only have high-efficiency thermal insulation, weather resistance, water resistance and good flame retardant effect, but also greatly improved the adhesion during fire.

2.3 Research on Flame Retardant Additives Another key component of energy-saving heat-insulating fire-retardant materials, flame retardant additives, has a great impact on the fire performance of energy-saving heat-insulating fire-retardant materials. The selected flame retardant must be compatible with the binder and other components of the fire protection system. In addition, economical, no toxic gas and smoke are generated in the fire, and the physical properties of the fire retardant material are basically not affected. It is also necessary to improve the weather resistance, water resistance and corrosion resistance of the fire-retardant and fire-retardant materials. In the research, the technical route of adding composite inorganic flame retardant materials to organic flame retardants was studied. Firstly, a new type of composite inorganic flame retardant was studied as a fire-retardant fire-retardant system for heat-insulating fire-retardant materials, so that the flame retardant not only has good The flame retardant effect is non-toxic, and basically does not generate smoke and poison gas when burned. Using a cone calorimeter, thermal analyzer, scanning electron microscope, etc. to study the flame retardant mechanism of the composite inorganic flame retardant in the fire retardant material and its effect on the safety and environmental protection of the combustion products; and using these test methods In-depth study on how to obtain excellent fire retardant effect after adding the composite inorganic flame retardant to energy-saving insulation materials, and having excellent physical and chemical properties and environmental performance.

Through research, we found that the flame retardant effect of borate, phosphate and metal oxide flame retardants is very good. They not only have good flame retardant effect, but also are non-toxic. They do not produce smoke and toxic gases when burned, have no environmental pollution, and are rich in raw materials. They are a new type of green environmentally friendly flame retardant. In the research, the technical route of adding inorganic composite flame retardant materials to organic materials is adopted, so that the new energy-saving heat-insulating fire-retardant materials researched by them not only have high thermal insulation performance and good flame retardant effect, but also are non-toxic and burning. It does not produce heavy smoke and poisonous gas, rich sources of raw materials, and low cost. The thermal decomposition mechanism, flame retardant mechanism, apparent density, thermal conductivity, water absorption, sound insulation performance, durability and mechanical strength of the composite flame retardant were studied.

According to the relevant information and domestic resources, a single performance test is conducted on the pre-selected flame retardant. The thermal insulation and differential thermal analysis were used to determine the thermal insulation and flame retardancy of the flame retardant, and the properties such as density, water absorption, heat resistance and corrosion resistance were also tested. The flame retardant of the fire protection system we choose is LL phosphorus and aluminum composite flame retardant, which is prepared by reacting phosphoric acid and aluminum hydroxide as raw materials under certain conditions.

The thermal decomposition mechanism of the composite flame retardant was analyzed by a thermal analyzer. The DTA and TG curves of the composite flame retardant are respectively observed under isothermal heating conditions.

Table 1 Effect of LL phosphorus and aluminum composite flame retardant on the performance of energy-saving and heat-insulating flame retardant materials LL Phosphorus and aluminum composite furnace average temperature rise sample average continuous sample average mass smoke gas tap water soaking heat and humidity test salt spray corrosion Sex test flame retardant dosage /% / zhang burning time / s loss rate /% toxicity 24 h24h3 times 013333.5za3 surface slightly blistering, no detachment surface color slightly changed shallow surface color slightly lighter 28031.3za2 surface basically no change surface basic No change surface, no change, no change, no surface change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no change, no surface change, 86030.7ZA1, slightly blistering, light color, slight surface, no change, surface blistering, color Lighter Note: The combustion performance test is carried out according to GB/T 5464-1999; the smoke toxicity test is carried out according to GB/T 20285-2006; the salt spray corrosion test and the heat and humidity resistance test are visible according to GB, and the flame retardant is The thermal decomposition process of 506001 has three endothermic processes. It has high-efficiency flame retardant effect and is non-toxic. It does not produce smoke and toxic gas when burned, has no pollution to the environment, has strong chemical bonding strength, high temperature resistance, good thermal stability, anti-vibration and anti-flaking. It is a kind of green environmental protection. High-efficiency flame retardant, because it is an alkaline phosphate, it is used in energy-saving heat-insulating fire-retardant materials not only to make the coating have high efficiency of fire and heat insulation, but also has a certain anti-corrosion effect. In order to improve the corrosion resistance and fire resistance of energy-saving heat-insulating fire-retardant materials, we have added a certain amount of flame retardant additives such as modified barium metaborate, aluminum polyphosphate and aluminum oxides in the research. In a large number of experimental studies, it was found that with the increase in the amount of LL phosphorus and aluminum flame retardant added, the corrosion resistance was decreased. The effect of the amount of LL phosphorus and aluminum composite flame retardant on the performance of energy-saving heat-insulating fire retardant materials was studied experimentally (see Table 1).

When the amount of the phenolic resin is 40%, the tube strength of the expanded vitrified beads can be nearly doubled.

In summary, when the amount of the phenolic resin is 40%, the compressive strength of the expanded vitrified beads can be nearly doubled. At this time, the bulk density of the expanded vitrified beads is increased by about 10 kg/m3, the water absorption rate is decreased by nearly 2 times, and the thermal conductivity is only slightly increased. Therefore, the surface properties of the expanded vitrified microbeads can be significantly improved by the phenolic resin reinforced modification.

3 Conclusion The expanded vitrified microbeads have been modified by phenolic resin to show more excellent performance, the cylinder strength is significantly improved, the water absorption rate is greatly reduced, and the thermal insulation properties and low density of the expanded vitrified beads are maintained. Characteristics. This makes the expanded vitrified microbeads more convenient to be used in the production of lightweight mortars, lightweight thermal insulation sheets, etc., and will effectively reduce the breakage rate of the expanded vitrified microbeads during the processing and transportation of related products, and maintain Granular integrity of expanded vitrified beads.

At the same time, modification by phenolic resin coating is also expected to further expand the application field of expanded vitrified microbeads. (Continued from page 75) It can be seen from Table 1 that after adding LL phosphorus and aluminum composite flame retardant to the energy-saving heat-insulating fire-retardant material, the fire-proof and heat-insulating effect of the heat-insulating flame-retardant material is greatly improved, but if LL phosphorus, If the content of aluminum composite flame retardant is too high, the heat-insulating and flame-retardant material will become brittle, the adhesion will be reduced, the resistance to moisture, water and corrosion will be reduced. The content of LL phosphorus and aluminum composite flame retardant is 4%~6%. Best performance.

2.4 Experimental research on energy-saving heat-insulating fire-retardant materials Through the experimental analysis, analysis and adjustment, re-detection and re-analysis, a large number of experimental studies have been carried out to develop the optimum amount of silicone-modified acrylic emulsion at a certain temperature. The optimum amount of blended modified emulsion, fire protection system and flame retardant additive, lightweight aggregate and other ingredients. In the specific method of formula design of energy-saving heat-insulating fire-retardant materials, we use advanced testing instruments and orthogonal design to achieve the purpose of improving the efficiency and reliability of formula design, so as to obtain excellent fire and heat insulation performance. And the formulation of energy-saving insulation fire retardant materials with physical and chemical properties.

3 The new energy-saving heat-insulating fire-retardant materials researched in the conclusion have excellent comprehensive performance and reach the advanced level at home and abroad. It has high fire retardant performance and combustion performance of A1 grade material; the energy-saving heat insulation fire retardant material is a lightweight thermal insulation, sound insulation and fire retardant material with low density and dry apparent density of slurry of 292kg/m3. The compressive strength is 350 kPa, and the thermal conductivity of 0.072 W (nrK) will bring great benefits to the lightweight and other aspects of the building. The insulation is fire retardant

(Finish)