Research and application progress of stone protective agent

   Stone as an important architectural decoration materials, has been loved by people and attention. From the medieval palace beautiful decoration to modern buildings without touch the sky, see the stone,. On the one hand because of the stone with very high strength and good physical and chemical properties, are widely used in various construction fields; another stone is beautiful and colorful hue and amazing changes texture, in appearance can also satisfy people aesthetic requirements. Divided into polished surface and rough surface texture on the surface of the stone, but because of the stone is composed of a variety of minerals and having a number of pores, easy react with other chemicals, both which surface will be subject to erosion and pollution.

   In recent years, with the rapid development of industry, the environment pollution of stone eroded more and more serious, serious impact on the stone of appearance. Human beings are gradually aware of the importance of stone conservation. People think of many ways to protect the stone from destruction, in the stone surface of the curing agent is the most widely used in the field of stone conservation methods. Stone curing agent significantly improved the appearance of decorative materials, in the field of stone conservation has an important role. 1 stone pathological changes and cause analysis

         To achieve better stone conservation, it is necessary to understand stone disease and its causes, symptomatic maintenance, so as to achieve twice the result with half the effort.

         There are many reasons for the stone diseases, which are divided into three categories: physical, chemical and biological.

1.Apparent phenomenon of stone pathological changes 

         Chemical lesion of the rust marks the general stone raw material containing higher iron content, and the air in the reaction of carbon dioxide and water form rust; at the same time stone in mining, processing, and transportation process, but also easy to form traces of rust water stains on the stone in the decoration construction process because of the role of cement mortar, cement, acid rain environment factors and in the pores of stone formed cement silicate gel, salt and other hygroscopic material and formation water spots physical lesions efflorescence wet pavement stone using alkali cement alkali and air in the acidic solution formed by the reaction of salts in crystalline form attached to the stone surface can appear efflorescence 

        Cracking when the ambient temperature changes, the stone and the bonding cement mortar expansion uneven, easy cause between the stone and bondingobject cracking 

        Biological lichenified lesions destroyed moss bud son to fly down the adhesion after the wet stone, the roots will secretion amount of H + ions, the H + ion will make the transition metal ions in minerals, be born moss nutrients 

2.stone curing agent development and protection mechanism 

          Stone protecting agent of history should be traced first 30 years of the 20th century, after 80 years of development, stone conservation agent has become the stone industry in the application technology of the fastest growing, one of the areas with the highest value-added products, the protective agent of the historical process and protective mechanism were briefly summarized. 

3.stone conservation agent of domestic and foreign research status and application 

   After the stone door of new stone protective agent should has the following seven characteristics: 1 waterproof, anti fouling, anti ultraviolet; fourthly, antifreeze, anti solubility; fifthly, keep the stone permeability; and reduce the daily maintenance support cost; seventhly, duplication and maintenance convenient for construction. 

3.1 stone conservation history 

   In stone as building materials and thousands of years long history, stone has been used as the structure of the building materials and basic materials used, but people do not consciously to its protection. Until the 1930s, Germany to the capital by Berlin moved to Fort York, when government stone curing agent in foreign countries has been the development of the years of history, Japan and Europe and the United States and other countries stone curing agent development and application has been in leading position, has gradually from solvent based products have crossed over to the water environmental protection products.

         And China stone conservation development began in the 1993 Hong Kong Aaron to enter the mainland, Aaron will Guangzhou Xiehe marble care company as its agent in the mainland, the stone care products, stone material face lifting equipment and materials in Guangdong and the mainland to promote, and in China to carry out renovation stone business. 

3.2 stone conservation agent foreign development status 

   Stone conservation agent mainly for coating type and infiltration type two kinds, infiltration and water diversion base type and solvent type. 

          Coating protective agent will stone completely sealed, to prevent water, oil, dirt from stone gap infiltration, this method due to prevent the stone itself to "breathe" channel, the stone itself at a disadvantage, so not stone curing agent development main direction, many foreign countries is no longer in production this product. 

         Penetration type curing agent by processing of the stone and then decreased on the surface of the stone can, to prevent water and dirt in the wetting of the surface of the stone and further prevent pollutants from penetrating into the interior of the stone. This treatment to maintain the permeability of stone, is the development direction of stone curing agent. Penetration type curing agent according to the material is subdivided into: 

         Of fluorides of stone conservation agent, the curing agent mainly composed of fluorinated monomer (meth) acrylic acid alkyl esters, fluoroalkyl vinyl ether and fluoro alkene modified polyester resin and acrylic resin and its main features is the acid resistance, alkali resistance, weather resistance, etc.. Such as: American putter Sen company production of fluorine stone curing agent of PIC series is a kind of solvent type protective agent, has strong penetration, effectively avoid water spots, Baihua, spit yellow rust, etc. all kinds of pollution, and keep the stone natural permeability and lasting effect. 

          Agent for maintenance of organosilicon stone, the curing agent mainly by organic silicon monomer alkyl silane, alkoxy base silane and vinyl silane modified styrene acrylic emulsion, polyester resin and its main features waterproof, weatherproof, sex etc.. Such as American Squibb Company production of the organosiloxane stone conservation agent K-66 can effectively prevent stone water variegated stem, Bai Hua, spit yellow and other diseases, the curing agent has excellent aging resistance using long life. 

           Fluorine silicon stone material maintenance and agents from the front of the containing fluorine and silicon organic matter of acrylic resin and polyester resin, and its main features a waterproof, anti oil, anti fouling, anti - aging. Such as the thought of Kang chemical production KY-60 silicon and fluorine ensemble protective agent is a solvent based products, with strong permeability, effectively penetrate into the inside of the base material, surface leave any worldly, do not change color stone, surface good painting, with excellent resistance to chemical and aging resistance and weatherability, lifetimes of up to 15 years, and oil proof, waterproof, moisture-proof, antifreeze, anti pollution, anti aging, and color retention function, no any toxic, harmless to the human body. 

3.3 domestic stone curing agent research and development 

   In recent years, the development of domestic stone curing agent rapidly has from the original waxing method to protect the stone to use penetration era stone type curing agent. 

         The using organic fluorine silicon material of stone protective agent prepared. By analysis of the stone protective agent has good hate water, adhesion, hardness and weatherability of is a good stone protective agent. 

         With fluorine acrylate as monomer prepared fluorinated acrylate polymers, and on the stone surface of the door. The results show that containing fluorine acrylate polymer on the stone is excellent waterproof, oil proof, oil resistant and acid and alkali resistance, used for the protection of all kinds of stone long effect. 

         With self-made environmental protection type fluorine-containing monomers of acrylate monomer, by solution polymerization method to obtain the stone protective agent low surface energy, have good anti pollution characteristic, improve the water resistance and acid and alkali resistant characteristics.

    Using nano surface effect, developed a kind of nano materials as the main ingredient, with environmental protection, non-toxic and harmless water stone conservation agent. Nano stone protective agent is a new theory based on the proposed by Professor of Institute of chemistry, Chinese Academy of Jiang Lei "binary collaboration nano interface material" based, using unique to nano material of nano surface effect, made a new stone protective materials. After nano protective agent, the stone material has a good wear resistance, anti fouling, anti stone disease, weathering resistance, aging resistance and so on. At the same time, show the characteristics of antibacterial, anti mildew and so on.

         This nano stone protection new agent will be widely used in decorative stone and related products.

4.research prospects 

    Stone protective agent research trend in silicone resin, fluorine resin, fluorine and silicone copolymer resin body direction development. The fluorine silicone resin has developed rapidly in recent years. Silicone resin, fluorine resin protective agent tends to be modified by polyester resin, acrylic resin and other materials to prepare a new type of protective agent. With the research carried out, the silicone resin. The application prospect of fluorine resin in stone is considerable. Through the repair of damaged stone, bright and clean, no defect of the stone surface is displayed in front of people. But stone curing agent function is limited after all, can't put all the hope in stone curing agent. To prevent damage to the stone surface, we should start from the stone of the mining, transportation, science, and construction, the only way to promote the rapid development of the stone industry.  

         SICONG chemical attention to silicone and organic fluorine functional new materials and new technology application development, in recent years has quickly adjusted to become a focus on competitiveness, market leadership and high added value business partners. In the stone protection technology, for the industry leader, for different stone products for the development of different materials for different needs of different products.