Materiais e métodos comuns para restauração de pedra

Na verdade, as pessoas têm feito esforços contínuos para explorar alguns bons métodos e materiais para reparar e compensar alguns defeitos comuns da pedra, de modo a melhorar a qualidade geral e o efeito da pedra, which is especially important in today’s large-scale production and application of stone, it is Just like people’s own pursuit of beauty. Of course, whether it is the beautification of human beings or the repair of stone defects, it is inseparable from the generation and application of some new technologies and materials. Introduce the old and bring forth the new, timely application of some scientific and reasonable new materials can make the effect of stone repair more perfect, and this effect should not be limited to the factory link, but should also be kept in the installation and use links to maximize the comprehensive benefits.

1. Apply wax
   Waxing the surface of stone slabs is the earliest application and the lowest cost, and it is also the most commonly used method by some stone manufacturers to obtain better gloss and slab surface effects. It can cover up some small cracks on the surface of the board, and it can also increase the luster and color of the stone. But this method and material can not fundamentally solve the problem, and the persistence of the effect is poor. If the waxed board is used outdoors, it will expose its original appearance in a short time. In addition, the wax-coated stone is not breathable because the wax blocks the stone pores, which often leads to stone lesions, and also makes it difficult to protect the stone. Wax also absorbs dust, making the surface of the treated stone easily polluted.
2. Unsaturated resin is applied to stone repair and reinforcement
   There are natural cracks and holes in some stone materials, which makes the surface effect of the board poor, and the damage rate is high during processing and installation, especially for stone materials and some large-scale boards. Portanto, people introduce unsaturated resin into the repair and enhancement of stone.
   The scientific name of the unsaturated resin we call is unsaturated polyester resin, when the linear polymer compound formed by polycondensation of saturated or unsaturated dibasic acid and saturated or unsaturated diol When it becomes a viscous liquid in a solid (usually styrene), we call it an unsaturated polyester resin. Unsaturated polyester resin is a kind of thermosetting resin, which can be cured into a high molecular network polymer under the action of heat or initiator. It is applied to the repair and enhancement of stone based on several aspects: fast consolidation speed; low viscosity, easy to use and operate; light color, good transparency; high colloid hardness, good polishing; simple preparation, low cost.
   • 1) Unsaturated resin is used for repairing the stone surface. Dilute the unsaturated resin to an appropriate viscosity, or add suitable pigments and powder fillers to repair holes and cracks on the stone surface. At this time, we call it stone surface glue . This kind of surface glue is mainly used for repairing cracks and defects on the surface of marble slabs and filling holes in travertine during factory production. When in use, the entire board surface can be scraped or partially repaired according to the defects of the board, and then placed naturally to cure the colloid and then polished or heated by the device to quickly cure the colloid and then polished.
   • Based on the above points, people have used unsaturated resin for stone repair for a long time, and have also achieved satisfactory results. No entanto, due to the shortcomings of unsaturated resin itself, it has some physical disadvantages as a stone repair material: the colloid has poor adhesion and strength; the colloid is brittle; the colloid shrinkage rate is large; The specific manifestations on the stone are: when the cracks on the stone slab surface to be filled and bonded are under force, the glue breaks; the colloid used for filling will shrink and sag after being consolidated and polished; the colloid shrinks and cracks in the stone joint. Portanto, people continue to explore the use of some more perfect resin materials for stone repair.
   • 2) Unsaturated resin is used to strengthen stone. Some stones with rich cracks and loose materials (mainly marble), especially large-scale slabs, are prone to fracture and damage during processing, handling and installation. Portanto, people also use unsaturated resin. Used for strengthening treatment of stone. Applying glue and back net to the back of the stone is currently a common method used by some stone factories to prevent stone breakage and damage. When using it, prepare an unsaturated resin to an appropriate viscosity, and then apply it on the entire back of the stone, or stick it again. A layer of fiber mesh is added to achieve the purpose of reinforcement and support. At this time, we also refer to this unsaturated resin as stone back glue.
   • Some disadvantages of unsaturated resin also make it have some problems as stone back glue: this kind of back glue is only coated on the surface of stone without penetrating effect, and will not strengthen the essence of stone; It is suitable for the treatment of some low-strength and easily broken stones when producing thin plates; the adhesive force between the adhesive layer and the stone is poor, and the plate is damaged after peeling; the adhesive force between the adhesive layer and the stone is poor, and the moisture resistance is poor. It is necessary to tear off the glue layer, otherwise the stone will be hollowed out. From a comprehensive analysis of these problems, it is not difficult to see that the plates treated with this reinforcing material only play a certain role in the factory stage, and during installation, if the layer of glue is torn off, the breakage rate of the plates is still very high .
   • 3) Marble glue When discussing unsaturated resin as a stone repair material, we must talk about marble glue, because this common stone repair material on the market is mostly made of unsaturated resin. In addition to the disadvantages of unsaturated resin, this kind of marble glue has a lot of solvents and fillers added during preparation, and the randomness of curing agent addition makes its consolidation degree and bonding strength worse. What’s more frightening is that it is also used by some people to anchor the pendant when the stone curtain wall is installed. Of course, the reason why it attracts people to use is that it is cheap in addition to being easy to use.
3. Epoxy resin applied to stone repair and reinforcement In view of the shortcomings of unsaturated resin, it has many problems as a stone repair material, which prompts people to look for other materials to make stone repair and reinforcement more perfect. With the continuous improvement of epoxy resin production process and quality, and the continuous innovation of curing materials, it has been used as a relatively scientific and perfect material for stone repair and reinforcement.
   • Epoxy resin generally refers to an organic polymer compound containing two or more epoxy groups in the molecule, and is usually processed into a liquid resin for use. Due to the active epoxy groups in the molecular structure, they can undergo cross-linking reactions with various types of curing agents to form high polymers with a three-dimensional network structure. It is applied to the repair and reinforcement of stone based on the following aspects: good physical properties, high bonding strength; relatively low colloid curing shrinkage; large controllable curing time, can be cured at room temperature or high temperature; appropriate molecular weight , adjustable viscosity, good wettability and permeability; the shrinkage rate is relatively low when the colloid is cured.
   • 1) Epoxy resin is used for repairing the surface of stone materials. Choose appropriate epoxy epoxy resin and curing agent, or add pigments and fillers to the epoxy resin in advance, and mix them in the form of A and B components in a determined ratio. It is used to repair holes and cracks on the stone surface, so it can also be called stone surface glue. Usually this kind of surface glue is also mainly used for repairing cracks on the surface of granite during factory production, repairing cracks and defects on the surface of marble slabs, and filling holes in travertines. When in use, the entire board surface can be scraped or partially repaired according to the defects of the board, and then placed naturally to cure the colloid and then polished or heated by the device to quickly cure the colloid and then polished.
     • Compared with unsaturated resin, epoxy resin has more advantages than unsaturated resin; its bonding strength is high, and the bonding part is not easy to crack; it has good permeability and can penetrate into the cracks to make up for bonding; the colloidal shrinkage rate is low. , the rubber surface will not be sunken after grinding; it can repair the common small cracks on granite. Epoxy resins are increasingly replacing unsaturated resins as stone repair materials.
   • 2) Epoxy resin is used for stone reinforcement. Since epoxy resin has good bonding strength, permeability and moisture resistance, it can also be used as an ideal stone reinforcement material for coating on the back of stone to prevent The stone is broken and broken. Epoxy resin is used as stone adhesive. Compared with unsaturated resin stone adhesive, it has some advantages: the colloid has a certain permeability and can enter the cracks to bond and make up; the colloid has excellent adhesion to the stone surface, and the glue The layer and the back net will not peel off; because of the high bonding strength between the adhesive layer and the board, the back glue and the back net do not need to be torn off during paving, and the damage rate of the board is relatively reduced.

No entanto, although epoxy resin has many advantages as a stone repair material, it still has some shortcomings: the curing time of the colloid is relatively long; Retrofit because many of the earlier refill lines were designed for unsaturated resins; more expensive to use than unsaturated resins. In response to these problems, our material manufacturers are also actively exploring to solve some contradictions between the curing time and application effect of epoxy resin. Some factories have also transformed their equipment to adapt to the application of epoxy resin in large quantities. Nevertheless, epoxy resin can still be used as an ideal stone repair and reinforcement material, and now some stone merchants in Europe have mostly adopted epoxy materials and techniques to repair and enhance large areas of stone. , and it can also meet the physical requirements for reinforcing materials in some stone-related standards.