res·in n. 1. Any of numerous clear to translucent yellow or brown, solid or semisolid, viscous substances of plant origin, such as copal, rosin, and amber, used principally in lacquers, varnishes, inks, adhesives, synthetic plastics, and pharmaceuticals. 2. Any of numerous physically similar polymerized synthetics or chemically modified natural resins including thermoplastic materials such as polyvinyl, polystyrene, and polyethylene and thermosetting materials such as polyesters, epoxies, and silicones that are used with fillers, stabilizers, pigments, and other components to form plastics.
For consolidant treatments, there is agreement that treatments confined to the outer surface are dangerous since they can result in spalling of the stone but there is no agreement on what would be an appropriate depth of treatment beyond the fact that it is obviously necessary to treat the stone deeply enough to consolidate the full thickness of the decayed zone. Some stone consolidants also have water repellent properties. Since it is dangerous to confine consolidation to the near surface this makes the use of a combined water repellent-consolidant problematic if it is considered best to confine water repellency characteristics to the outer surface.The ideal polymer for use in stone consolidation would be one which can reverse the degradation of a stone, returning it as nearly as possible to its original condition. In order to achieve this the treated stone should mimic sound stone in as many characteristics as possible. Some characteristics are, however, more important than others. The most important include strength, porosity, permeability, thermal dilation and colour. Of all the polymers tested, silanes seem to hold out the most promise although they may not be suitable in every situation. The theoretical end product of polymerisation of the simplest silanes is silica which is present as a cementing mineral in many sandstones and may mimic the behaviour of a natural cement more closely than many other polymers.
Silane-based materialsSilane-based materials are generally organosilicon compounds which polymerise inside the stone. Some water is needed to aid the reaction, but the amount is critical; a high humidity means the reaction may take place too quickly and too much water leaves no space for the polymer to form. The end product of polymerisation is silica, similar to the natural silica deposits which bind many sandstones. Penetration can be quite deep but this depends greatly on the product used and the conditions in which it is applied.By the production of silica there is a definite consolidating effect and many silane-based products seem to increase the strength (flexural, compressive, tensile etc) of damaged stone. Unfortunately, there is some colour change with most types of silanes, although studies show that this usually lessens after about 18 months. Porosity, water absorption and pore size distribution have shown to be affected by the treatment, a little in some cases and a lot in others. This influences resistance to salt crystallisation and freeze/thaw action. Where there is a new area of stabilised decayed material, moisture evaporation has to take place within the stone and this may lead to salt crystallisation at the boundary between treated and non-treated stone.These are the main silane-based products and their main features: * tetraalkoxysilanes - have little water repellency; * alkyl trialkoxysilanes (such as brethane) - less consolidation, but good water repellency; * polysiloxanes - flexibility and more water repellency; * silicon hydrides - use presents many health and safety problems; * halogen bearing silanes - generate damaging acids, so thought to be too dangerous to use in conservation.
i think when used in the context of rock repairing the word "resin" isn't exclusivley used to mean "pine resin":Quoteres·in n. 1. Any of numerous clear to translucent yellow or brown, solid or semisolid, viscous substances of plant origin, such as copal, rosin, and amber, used principally in lacquers, varnishes, inks, adhesives, synthetic plastics, and pharmaceuticals.
res·in n. 1. Any of numerous clear to translucent yellow or brown, solid or semisolid, viscous substances of plant origin, such as copal, rosin, and amber, used principally in lacquers, varnishes, inks, adhesives, synthetic plastics, and pharmaceuticals.