Domestic Development of Research and Development of Waste Plastics Used in Building Waterproof Materials Ji Lianqing\ Liu Chaofeng2 Shao Jianmin1(1. School of Mechanical and Electrical Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, China; 2. School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan Province 450002, China) New domestic developments in the research and development of coils, waterproof coatings, construction seals, and construction waterproof insulation materials. Looking forward to the research and development focus and hot spots in this field.
1 Introduction With the rapid development of the plastics industry, a large number of plastic products are used. At present, the world’s plastic production has reached nearly 140 million tons. At least 40 million tons of waste plastics are waiting for treatment each year. China has more than 1 million tons of disposable agricultural plastic film and Packaging plastics seriously pollute the environment. Among them, waste polystyrene foam, which accounts for the largest proportion of waste plastics, is used as a packaging material for one-time use. Its waste structure is very stable, it is difficult to be degraded by the light and heat of nature, and almost no plastic is digested in nature. The bacteria will also pollute the groundwater sources, destroy the soil structure and reduce the production of food crops. If it is simply incinerated, the benzene ring may cause serious pollution of the atmosphere due to insufficient temperature during combustion. If the plastic is discarded at random and easily eaten by cattle, horses and other animals as food, the plastic cannot be digested in the animal's intestines and it will cause the animal's gastrointestinal body to be damaged or die. If it is purified, pulverized, granulated by an extruder for use in recycled plastics or closed heat cracking for the recovery of styrene monomer, a large investment is required, resulting in poor product performance and low efficiency. Therefore, the comprehensive utilization of waste polystyrene foam is one of the urgent issues to be solved. At present, people have explored and practiced the use of foamed polystyrene and other waste plastics in the construction of chemical building materials. Waste plastics are used in waterproof building materials and are expected to create considerable economic and social benefits. It is an effective way for the comprehensive utilization of waste plastics to produce products that meet different waterproof requirements through different modification methods and processes. For example, more research and development at this stage is the use of waste polystyrene foam to produce modified PS series coatings and adhesives. With the use of waste expanded polystyrene (PS) as a raw material, together with a small amount of plasticizer, the waterproof and anti-corrosion performance of the paint produced by the hot-melt process greatly exceeds the commonly used asphalt grease, and its service life can reach more than 20 years; Polystyrene waste can also be made into colored waterproof coatings for roof waterproofing. It can also be used for advertising decoration and color flame retardant waterproof coatings for interior and exterior walls.
Building waterproof materials are often divided into five categories: polymer modified bituminous waterproofing membranes, synthetic polymer waterproofing membranes, waterproof coatings, sealing materials, and rigid waterproof and plugging and sealing materials. Among them, high-quality special-purpose raw materials required for the production of domestic high-performance waterproof materials are almost all imported. In order to save foreign exchange, many of China's polymer waterproof materials are produced using waste plastics as raw materials. In order to improve the performance of these waterproof materials, domestic research and development personnel have done a lot of work. 28. The following summarizes the use of waste plastic in building waterproof materials. Applied domestic research and development.
2 Polymer Modified Bituminous Waterproofing Sheets Bituminous waterproofing membranes are the traditional materials for construction waterproof engineering worldwide. They mainly include bitumen and tar batts and high polymer modified bituminous waterproofing membranes. In the construction of paper tar mats, environmental pollution will occur. In recent years, some countries have banned the use of paper tar felt construction in urban areas, and at the same time, polymer-modified bitumen waterproofing membranes have replaced paper tar tar felts. Polymer-modified bitumen membranes mainly include APP and SBS as the waterproofing materials for modified materials, mainly polyester tires and glass fiber tires.
Asphalt is an important part of bituminous waterproof material, and its performance directly affects the quality of waterproof material. At the same time, the production of isotactic polypropylene (PP) by-product atactic polypropylene (5% to 10% of output) has no other large-scale industrial use and is a cheap material. Long Bin et al.2 used waste polyethylene (PE) and PP to modify the waterproof material 10 bitumen and found that the best ratio is 5g) The modified bitumen and unmodified bitumen were observed under an electron microscope. In the process of melting, PEPP (random) swells and the intertwined chains of macromolecules are pulled apart by bituminous molecules into a 'network', thereby increasing the high temperature stability of the asphalt; at the low temperature, the polymer vitrification. In the state of temperature, the strength of asphalt increases, resulting in the following effects: First, it acts as a stress concentration center, induces a large number of silver lines and shear bands, and the generation and development of silver lines and shears consumes a large amount of energy, and thus can be significant. Improve the impact resistance of asphalt; Second, the macromolecule chain of PEPP (random) is more supple, and exists in the entire mixed system, so that the asphalt has a good low-temperature crack resistance. In addition, Huang Zhishan uses a variety of recycled plastics, such as polychlorinated Blended resins such as ethylene (PVC), PE, PP, and PS modified the coal tar pitch. The results show that when the performance of the hybrid resin modified clay is the best, the ratio of the components of the waterproof cement mortar is: coal Oil asphalt (including 10% PVC) 100 parts, dibutyl phthalate 3 to 8 parts, hybrid resin 10 to 15 parts, talcum powder 20 to 40 parts, asbestos velvet 7 to 1H parts asphalt waterproofing membrane due to its temperature Poor adaptability, short aging time, low tensile strength and elongation, especially when used in exposed waterproof, easy to play drums, runny, cracking at high temperatures, cold and brittle fracture at low temperatures, shorter service life; another evening, Due to the construction of multi-layered structures with hot work, construction is inconvenient, quality is difficult to guarantee, maintenance is difficult, and the site is contaminated, which is detrimental to the health of operators. Therefore, in order to improve the waterproof quality and reduce the labor intensity of construction, many new types of waterproof materials have been developed. Such as EPDM rubber waterproofing membrane and polyurethane waterproof coating, etc. However, due to the fact that some of the raw materials used to produce these materials cannot be completely self-sufficient in China, they are expensive and difficult to popularize, and people expect a moderate price, excellent performance and convenient construction. The new waterproof material.
3 Polymer waterproofing membranes China's polymer waterproofing membranes mainly include EPDM, polyvinyl chloride, chlorinated polyethylene, chlorinated polyethylene-rubber blends, rubber and plastic blends, reclaimed rubber, and geomembrane impervious Coil, polyethylene polypropylene and other waterproof membrane. In recent years, a large number of construction of water conservancy and sports stadium projects have resulted in a large amount of EPDM waterproofing membranes. The prices of PVC waterproofing membranes developed and produced in China are relatively modest, and only the Shenzhen Convention and Exhibition Center project has applied a 110,000 m2 trial. Underground, hydraulic materials, SBS''polyurethane'', 'acrylic'' materials, construction cost is too high, users find it difficult to accept. Therefore, the development of low-cost polymer waterproofing membranes has become the key to the promotion of such waterproof materials. Therefore, it is difficult to rectify the low defect toughness of the coils in the market, and local defects are difficult to correct. Wu Yan 1 used the wastes from the coking plant, the kiln dust from the cement plant, the waste plastic from the garbage dump, coal tar, and PVC blends. The new type of waterproof material made of thermoplastic, crosslinked and compounded has the characteristics of good flexibility at low temperature, cold work construction, single layer waterproof, and one-time waterproof operation.
According to another report, the waste expanded polystyrene was washed and dried, dissolved in a cheap benzene solution or chlorocarbon residue, and added with a toughening agent and a film-forming anti-seepage and wear-resistance agent to form a viscose, which was blown or coated. The surface of the glass cloth is dried into a waterproof membrane for the roof or pipe.
In the field of waste plastics used in waterproofing membranes, there are few domestic studies, which may be due to the industrialized production process and equipment of waterproofing membranes. However, an invention patent in this field indicates that waste plastics are applicable to waterproofing membranes. . In contrast, research conditions for waterproof coatings are easier to create, so the results are more abundant. Polystyrene-resin adhesives are made of scrap PSF. The adhesive is used as an intermediate to prepare roofing waterproof plugging coatings. Experiments show that toluene and acetate are used. Polystyrene, acetone and other solvents modified polystyrene can achieve the best dissolution. Min Zunzhou and others used unsaturated polyester and reactive monomers to graft and modify polystyrene to obtain a good emulsion type waterproof coating. The mechanism was: Graft modification of polystyrene was introduced into its molecular chain. The flexible side chain bond with internal plasticization effect provides good low temperature flexibility of the coating film; the crosslinking reaction of the active monomer in the film formation and curing process increases the elongation at break of the coating film and gives the coating a good waterproof performance. In addition, Gu Xupeng, Li Liangbo, etc. used rosin modified phenolic resin to prepare a waterproof coating, Li Bin used 871 resin to develop a wear-resistant waterproof coating, Lei Yuying chose xylene, n-butanol, and ethyl acetate as solvents, and in order to enhance The polarity of the coating film and the adhesion of the coating were successfully developed using rosin, phenolic resin, and toluene diisocyanate to prepare a low cost, modified PS waterproof coating.
Song Xuejun et al. selected a petroleum cracking by-product of the composition and properties shown in Table 1 as a solvent, using waste polystyrene as a resin and then adding an emulsifier. Solid fillers. Body pigments. Plasticizer developed into a paint. The paint is quick-drying at room temperature, has good waterproof and anti-corrosion properties, strong adhesion force, strong impact resistance, and its coating film is bright and beautiful, and is suitable for use as an exterior wall coating. The best formula of waterproof coating developed by Wei Qingli etc. is foam plastic 100g, mixed solvent 145g, plasticizer (dioctyl phthalate) 25.5g, emulsifier 13g, water 110g, silicone monomer 12%, KH- 5701%, AA 3%, N-methylol acrylamide 4%, hydroxyethyl 4%, reaction temperature 70-75°C, reaction time 2-3h The water resistance time of the prepared waterproof coating is greater than 360h. Table 1 Composition and properties of mixed solvents According to Wu Enting et al.'s patent, waste polystyrene foams were collected by distillation to collect the gas phase components, and the cooled mother liquid was modified by adding clean polystyrene foam to obtain polystyrene resin, and then Add auxiliaries containing rosin and lead Dan to mix and apply waterproof and anti-corrosion coating. Adjuncts can also be filled with fillers, dioctyl phthalate or SBS. The invention uses 100% of waste polystyrene foam, waterproof effect, and easy construction.
It can be seen that in the field of waste plastics used for waterproof coatings, although there are many researchers, there are fewer invention patents, indicating that much work needs to be done to convert research results into actual productivity.
5 Construction Sealing Materials China's construction seal materials include plastic grease. Asphalt grease and polysulfide. Silicone. Polyurethane. Neoprene. Butyl seal putty. Chlorosulfonated polyethylene and other elastoplastic sealing materials. In recent years, polymer sealants have been used for glass curtain walls. structure. Stone. Metal roofing. Ceramic tiles and automobiles. Polysulfide sealant is mainly used for insulating glass windows in water conservancy projects and municipal water plants. Sewage works and wallboard joints also have good applications. The construction seals also employ a large amount of bitumen-based caulking compounds. The most commonly used amount is coal tar PVC paste. According to information, the waste polystyrene foam after washing and drying is dissolved in acetone and ethyl acetate, completely melted by adding butyl acrylate and acrylic acid, and the initiator benzoyl peroxide is added at 75-85C to conduct the connection. Polycondensation for 4-6 hours according to the amount of polystyrene added, rosin glyceride and Coumarone resin were added, and 5%-10% of flame retardant and 15% of light magnesium carbonate were added according to the total weight of the reactants. Strong production bond. Good adhesion. Fast film-forming waterproof, moisture-proof adhesive. The glue does not soften at high temperatures and is not sticky. A low temperature of 20C is soft and not brittle. And non-toxic flame retardant. The engineering application shows that the rubber project has low construction cost, good effect and simple construction. Its main material is made of the following parts by weight of raw materials: 5 to 15 parts of waste liquid after industrial extraction of polystyrene, coal tar, East oil industrial miscellaneous oil. 25-35 parts of asphalt or their mixture, 5-15 parts of waste polystyrene foam, and 0.05-0.3 parts of defoamer; auxiliary materials are powdery building materials that adjust the viscosity of main materials, and their weights are mainly 0.1-0.3 parts. The glue can be used as a waterproofing membrane adhesive. There are also two inventions that disclose the process of processing rubber glue for waste rubber and plastics: waste rubber and waste plastics are washed and dried, then added with solvent and warmed to 180--4 h for cooling and filtering; add modifiers and mix well and serve. When the waterproof plastic waterproof roof is constructed, it is not required to be heated, and it is directly smeared. The waterproof performance is good and the service life is long.
Tan Zhumin 120 will be a variety of waste polystyrene plastic. Polyurethane plastic. PVC plastic. The urea-formaldehyde foam lysate was added with petroleum pitch. Ethyl acetate. Cyclohexanone. The water-repellent plaster composition obtained by polymerizing waste plastics in a certain ratio has a long-lasting anti-water molecule penetration effect, good anti-aging properties, strong adhesion, good resistance to heat and cold changes, good flexibility, and suitable curing time. With a wide temperature range, it can be used for waterproofing of various buildings and projects. Moisture proof and plugging.
Xu Yi used waste polystyrene foam to prepare a modified PS adhesive. The experimental results showed that by adding phenolic resin. Styrene butadiene rubber and rosin and isocyanate modifiers, in an appropriate solvent (ethyl acetate-trichloroethylene-120 gasoline system), to control the appropriate polymerization conditions (reaction time in the 4- 5 small B inch, temperature control (50C is the best) to produce excellent construction adhesives that can be used in water-resistant interior decorative adhesives. Cement blocks and tile adhesives and wood adhesives.
Wang Xiuyan invented a kind of water resistance made from waste polystyrene as base material. The outstanding architectural adhesive for cold resistance is suitable for toilets and rooms.
Fish tank. pool. swimming pool. Broken bridge repair and other waterproof. It is used in places with high moisture resistance requirements and the cost is low.
In the field of waste plastics used in the construction of sealing materials, due to the R & D tools and implementation is not very complicated, there have been five inventions and two research results, and it is expected that this field will become the focus of research and development.
6 Waterproof and thermal insulation materials are exposed to direct sunlight or covered by rain and snow. Leakage of roofing brings huge losses to the building itself, interior decoration, furniture, and home appliances. With the pursuit of high-quality living conditions, high-quality roof insulation and waterproof materials have received increasing attention. The ordinary asphalt linoleum structure does not have long-term anti-aging properties, and the cracking of cement-based inorganic materials has been plaguing the construction industry.
New materials for thermal insulation in China include rigid foamed polyurethane, extruded polystyrene foam, and hydrophobic expanded perlite. The disadvantages of these materials are: First, the complementarity is poor, and the failure of waterproof materials will be directly Impact on the performance of insulation materials; Second, the cost of roofing projects is expensive. Therefore, the search for a low-cost, self-waterproof, waterproof, green waterproof material has certain economic benefits.
Mi-Ming's glue is made from in-house material and auxiliary ublish surface e-construction with 1 Poly B! The acetal-reduced i-formaldehyde adhesive has good waterproof and heat-insulating properties both at the bookmark2 fly ash and the waste foam, and both belong to the solid waste, and has the advantage of price as a building material. However, the problem that needs to be solved when developing a waste-foam plastic-fly ash waterproofing and heat-insulating material is that the surface of the used foamed plastic is water-repellent, resulting in incompatibility with the cement-mixed fly ash cementing material; in addition, due to the small particle density, during the preparation process There will be an increase in the water, which will lead to a decrease in water retention. Foam modification technology can be achieved by: (1) crushing waste foam into foam particles with a particle size of less than 20 mm, and using irregularly multiple composites of cement and fly ash into a low water-to-rubber composite bond material. Composite binder material for complete encapsulation of foam particles. Based on this, Ni Wen and Niu Fusheng used fly ash and ordinary portland cement as cementing materials, and used waste foam as aggregate, supplemented with water-repellent agent and micro-expansion agent to develop waste-foam-powdered coal. Gray waterproof insulation material. The construction process of the material: the base layer adopts a low water-cement ratio mortar or fine sand as the screeding layer, and a double-layered high-quality anti-aging film is used as a preset waterproof layer, and then is poured on it (small area) or masonry used foam. A plastic fly ash waterproof and heat-insulating material block, wherein the sub-lattice seam or the jointing mortar adopts a micro-expansion mortar made by adding a self-expanding expanding agent. The insulation mechanism of the material can be explained as follows: The foam plastic contains a large number of micropores, the thermal conductivity is small, and it has a good thermal insulation performance. Fly ash is also an active material with a very small thermal conductivity. The material has good thermal insulation properties; in addition, as a pre-determined waterproof layer, the double-layer high-quality anti-aging film under the protection of the bottom mortar and the upper insulation block, the air layer between them has more excellent thermal insulation.
The three reasons for the waterproofing of this material are: high density of strong punching molding; the addition of fly ash-cement cementing material and micro-expansion agent to form hydration crystals and gels are continuously filled into the micropores of the material. The solidity of the matrix part of the material is continuously improved and micro expansion occurs; at the same time, a large amount of fly ash can quickly consume most of the Ca(OH)2 produced by cement hydration, avoiding the formation of Ca(OH) crystals and Dissolves to leave pores upon contact with water. The addition of water-reducing agent and water-repellent agent gradually forms a dispersed film during the hardening and drying process of the cementitious material, blocking a large number of micron and sub-micron-sized pores, making the matrix impervious to water; the waste foam accounting for 80% of the volume has a good The hydrophobicity is not deformed after immersion in water, and there is no through-hole structure. In addition, double-layered high-quality anti-aging films will continue to provide waterproofing with good flexibility in the event that the underlying structure causes uneven cracking of the roof structure. Since the foam plastic has a large rebound ability after being pressed, it is not easy to produce tensile cracks when the heat-insulating water-proof layer is freeze-shrinked. The material is subject to large outdoor exposure both in the hydration hardening period and in the long-term service period. When the temperature changes, they are always under the stress of micro-pressure and can effectively prevent the occurrence of tensile cracks. The material can be applied to the surface of new and old roofs. The original waterproof layer or mortar and protective layer of the old building can be constructed without removing the material.
In addition, Jiang Zhengwu et al. used a cement, polymer latex powder, waste PP fiber, bentonite, water-based silane/silicone emulsion, quartz sand, and water for building interior and exterior walls prepared according to a proper ratio and a certain process. Environment-friendly waterproof insulation mortar with excellent thermal insulation, and good water resistance, waterproof, impermeability.
There is also a waterproof sheet for decoration, plant fibers such as straw, fly ash, and maleic anhydride, phthalic anhydride, polyhydric alcohols, styrene or melamine, acrylic acid, or rosin, and bicyclopentane The mixed binders of olefins, as well as new and old plastics, are made by blended compression molding.
The research and development of waterproof and heat-retaining materials, in spite of the large investment in research and development, are more effective in the research and development of materials for waterproof and heat-insulating materials, but this area can play the role of waste plastics and belongs to the large-volume use of waste plastics. It can be predicted that more and more developers in the field will be engaged in the near future. The more you come.
7 Conclusion The use of waste plastics for the production of waterproof materials for construction is an important way to solve the problem of plastic solid waste pollution. Producing waterproof material with waste plastic can reduce the price of the waterproof material, and can also improve the performance of the waterproof material. The research methods and test methods of waste plastics used in high-polymer materials, construction seal materials and building waterproof insulation materials provide us with feasible research methods. The use of waste plastics to produce waterproof materials for construction is of practical significance and is a new topic that we are eager to solve.
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