People have been constantly trying to explore some good methods and materials to repair and make up some common defects of stone materials, so as to improve the overall quality and effect of stone materials. This is particularly important in today’s large-scale production and application of stone materials, which is just like people’s pursuit of beauty. Of course, no matter the beautification of human beings or the repair of stone defects, it is inseparable from the production and application of new technologies and new materials. The effect of stone repair can only be more perfect if the old are introduced and some scientific and reasonable new materials are applied in a timely manner. This effect should not be limited to the factory link, but also be kept in the installation and use the link to maximize the comprehensive benefits.
Wax coating on the stone surface is the earliest method with the lowest cost. It is also the most common method used by some stone manufacturers to obtain better luster and surface effects. It can cover some small cracks on the board surface, and also can increase the luster and color of the stone. However, this method and material can not fundamentally solve the problem, and the effect is less durable. If the waxed plate is used outdoors, it will expose its original appearance in a short time. In addition, the waxed stone is not breathable because wax blocks stone pores, which often leads to stone lesions and makes stone protection treatment difficult. Wax can also absorb dust, making the surface of treated stone easy to be polluted.
2. Unsaturated resin shall be used for stone repair and reinforcement
Some stone materials have natural cracks and holes, which make the surface effect of the plate poor, and the damage rate is high during processing and installation, especially for stone materials and the use of some large-sized plates. Therefore, the unsaturated resin is introduced into stone repair and reinforcement. Stone Institute (IDstone5A)
Unsaturated polyester resin is a thermosetting resin, which can be solidified into a polymer network polymer under the action of heat or initiator. Its application in stone repair and reinforcement is based on the following aspects: fast consolidation speed; Low viscosity, easy to use and operate; Light color, good transparency; High colloid hardness, and good polishing property; The preparation is simple and the cost is low.
1) Unsaturated resin is used for repairing stone surface
Dilute the unsaturated resin to an appropriate viscosity, or add appropriate pigments and powder fillers to repair the holes and cracks on the stone surface. At this time, we turn it into stone surface glue. This kind of glue is mainly used to repair the cracks and defects on the surface of marble plates and fill the holes of cave stones during factory production. During use, the whole board surface can be scraped or partially repaired according to the defects of the board, and then it can be naturally placed to solidify the colloid and then polished, or the colloid can be quickly solidified by heating the device and then polished. Youshi Mall (www.5ustone. com)
2) Unsaturated resin is used for strengthening stone
Some stone materials with rich cracks and loose materials, especially large-sized plates, are prone to fracture and breakage during processing, handling, and installation. Therefore, the unsaturated resin is also used for strengthening stone materials. Glue and mesh coating on the back of the stone is a common method currently used by some stone factories to prevent the stone from fracture and damage. During use, the unsaturated resin is prepared into an appropriate viscosity, and then coated on the whole back of the stone, or a layer of fiber mesh is coated to achieve the purpose of strengthening and supporting. At this time, we also refer to this unsaturated resin as the back glue of stone.
3), marble glue
When discussing unsaturated resin as a repair material for stone, it is necessary to talk about marble glue, because most of the common stone repair materials on the market are made of unsaturated resin. In addition to the shortcomings of unsaturated resin, the consolidation degree and bonding strength of this marble adhesive become worse due to the addition of a large number of solvents and fillers and the randomness of the curing agent. What is more terrible is that it is also used by some people to anchor the pendant during the installation of the stone curtain wall. Of course, the reason why it attracts people to use it is not only convenient but also cheap.
3. Epoxy resin is applied to repair and strengthen the stone
The shortcomings of unsaturated resin make it have many problems as a stone repair material, which urges people to look for other materials to make the stone repair and reinforcement effect more perfect. With the improvement of the production process and quality of epoxy resin 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 refers to the organic macromolecular compound with two or more epoxy groups in its molecule, which is usually treated as liquid resin for use. Because the molecular structure contains active epoxy groups, they can cross-link with various types of curing agents to form polymers with a three-dimensional network structure. Its application in stone repair and reinforcement is based on the following aspects: good physical properties, and high bonding strength; The gel curing shrinkage is relatively low; The curing time is controllable, which can be cured at room temperature or high temperature; Suitable molecular weight, adjustable viscosity, good wettability, and permeability; The shrinkage of the gel is relatively low during solidification.
1) Epoxy resin is used for repairing stone surface
Select appropriate epoxy resin and curing agent, or add pigment and filler to the epoxy resin in advance, and mix them in the form of components A and B according to the determined proportion to repair the holes and cracks on the stone surface, so it can also be called stone surface adhesive. Usually, this kind of surface glue is also mainly used to repair the cracks on the granite surface, the cracks and defects on the marble plate surface, and the holes in the cave. During use, the whole board surface can be scraped or partially repaired according to the defects of the board, and then it can be naturally placed to solidify the colloid and then polished, or the colloid can be quickly solidified by heating the device and then polished.
Compared with unsaturated resin, epoxy resin has more advantages as a stone surface adhesive; Its bonding strength is high, and the bonding part is not easy to crack; It has good permeability and can penetrate into the crack to make up for adhesion; The gel shrinkage is low, and the rubber surface will not sag after polishing; It can repair the common small cracks on granite. With more and more trends, epoxy resin is replacing unsaturated resin as a repair material for the stone.
2) Epoxy resin is used for strengthening stone
Because epoxy resin has good adhesive strength, permeability, and moisture resistance, it can also be used as an ideal stone reinforcement material to prevent the stone from breaking and damaging when coated on the back of the stone. The epoxy resin is used as the stone backing. Compared with the unsaturated resin stone backing, the epoxy resin has such advantages: the gel has a certain permeability, and can enter the cracks to bond and makeup; The adhesion between the colloid and stone surface is excellent, and the adhesive layer and back net will not peel; Due to the high adhesive strength between the adhesive layer and the board, the back glue and the back net do not need to be torn off when paving, and the damage rate of the board is relatively reduced.
However, although epoxy resin has many advantages as a stone repair material, it still has some shortcomings: the curing time of colloid is relatively long; The distribution ratio of group AB was relatively strict; During assembly line operation, the existing drying equipment needs to be modified, because many previous glue filling lines were designed according to unsaturated resin; The use cost is higher than that of unsaturated resin.
In view of these problems, our material manufacturers are also actively exploring solving some contradictions between the curing time and the application effect of epoxy resin. Some factories have also modified their equipment to adapt to the application of epoxy resin in large quantities. In spite of this, epoxy resin can still be used as an ideal stone repair and reinforcement material. Now some stone manufacturers in Europe have adopted epoxy materials and processes to repair and strengthen large areas of stone, and it can also meet the physical requirements for reinforcement materials in some stone-related standards.