Chemicals are used at various stages of the production process and in everyday life. One of these varieties are synthetic resins. These substances differ in composition and scope. The purpose of artificial resins can be very diverse. Depending on the production method and composition, their main characteristics are determined. Resins of artificial origin will be discussed later.
general description
The production of synthetic resins began actively at the beginning of the last century. Artificial polymers have a number of characteristic differences from natural varieties. The fact is that the composition created by man has special properties. They can be set at the manufacturing stage. The compositions may vary significantly, which determines their scope.
Today about 5 tons of artificial polymers are produced annually in the world. Synthetic resins and plastics are obtained by processing coal, oil, gas or other natural components. Chemical compounds that are obtained in this way have a low molecular weight. Moreover, they can be produced not only in the form of a sticky thick mixture. It can also be a powder or granular substance.
Synthetic and natural resins, hardening, provide high-quality adhesion to different materials. In polymer compositions, this characteristic is more pronounced. When the artificial resin hardens, it can form excellent adhesion to concrete, metal, glass and other building materials. The curing process in this case occurs under the influence of high temperatures or catalysts. In some cases, in the process of creating a high-quality compound, extrusion is additionally applied.
Some artificial formulations need only time to harden. The result is a substance resistant to various adverse conditions, which is not afraid of temperature changes, mechanical stresses. They are not destroyed by exposure to water, alkali, acid, gasoline or oil.
Such features determine the scope of the presented compositions. They are stable, unlike natural analogues, are characterized by high performance. The scope of their application is extensive.
Production Features
Synthetic resin is a polymer that is produced during certain chemical reactions. The result is a high molecular weight compound with a given set of qualities. Resins of artificial origin are obtained by polycondensation or polymerization. These two processes are based on different principles.
Polymerization is a series of reactions during which a given number of elementary constituents are combined into complex molecules. No by-products are formed.
Polycondensation is a process in which simple molecules are converted into complex compounds, creating organic matter. This happens by creating new carbon bonds with other atoms.
Today, both types of resins are used in various fields of human activity. The choice of material type depends on the requirements for the result of the work performed. During the production of synthetic resins and plastics, two types of compositions are obtained:
- thermoactive;
- thermoplastic.
Thermoactive resins of artificial origin are a substance capable of melting only in a certain temperature range. If the environment does not correspond to the specified framework, the substance becomes non-melting and insoluble. Moreover, a similar property appears both with an increase and with a decrease in temperature above the set limit.
Artificial thermoplastic resin retains ductility and fusibility under all conditions. Depending on the type of feedstock, production method, an emulsion, powder, granules, blocks or sheets of polymeric material can be obtained.
Application
Synthetic and natural resins are used in various fields of human activity. But artificial options are more widespread due to their special qualities. It is easier to list areas where such substances are not used, than vice versa. The scope of their use is extensive.
One of the main areas of application of synthetic resins is the production of varnishes, paints, adhesives, as well as abrasives. Due to their ability to polymerize, such substances have special properties that are required in the manufacturing processes of artificial stone, plastic, and PVC.
Due to its good adhesion, the resin forms a high-quality compound with concrete, metal, glass, as well as a whole list of other materials. Artificial polymer compositions are resistant to various adverse conditions.
There are many materials based on synthetic resins. Artificial stone is made from polymers today. Various products are made from it, for example, window sills, sinks, countertops and various furniture.
Such materials create a monolithic floor covering. Synthetic resins are also used in woodworking. They allow you to create high-quality coating for natural materials. In construction, various industries, a variety of resins of artificial origin are used. Even in medicine and beauty industry, such compounds have found their application.
Epoxy resins
Today, many types of synthetic resins are produced. The most famous and widely used polymer compositions should be considered in more detail.
One of the most popular varieties is epoxy. The composition may have a liquid consistency or be produced in solid form. This substance has no color. Two-component epoxies require a hardener. Without a catalyst, the composition will not harden. To polymerize faster, you need to increase the temperature of the resin.
Epoxy resin has good adhesion. This allows you to fasten ceramics, metal, earthenware and a number of other materials. In its pure form, epoxy resembles honey.
This substance is obtained during the polycondensation of phenol and epilchloridrin. Amines and alcohols are also involved in the reaction. In this category, there are several substances that differ somewhat in their qualities. So, polyepoxides have a low density and are able to bond well with metal, stone. At the same time, the material practically does not shrink, and is resistant to acid.
Non-cured epoxy-dianic substances are thermosetting synthetic resins. They can have a shade of yellow to brown. Viscosity may vary. These are materials that can be either liquid or solid. The epoxy-diane resin is dissolved in dioxane, ethers.
Cured varieties of epoxy resins are insoluble. As a catalyst, polyamides, phenol formaldehydes, etc. can be used.
Epoxy polymers are used in the production of adhesives, which are used to create a strong connection of natural stone, concrete, ceramics, etc.
Polyester and Acrylic Resins
In the field of production of synthetic resins and plastics, such a variety as polyester compositions stands out. This material is created during the processing of alcohols. This resin allows you to create a less durable connection than the epoxy composition. But due to the nature of production, polyester varieties are cheaper. At the same time, it is easier to work with such resins.
The largest consumers of products of this type are the auto and shipbuilding industries, and the production of lighting equipment. Polyester resins are also needed in the manufacture of partitions, showers and window sills. The presented material easily bends after hardening, and can be painted using appropriate compositions.
Acrylic synthetic resins are used in the production of plastics, mosaics, artificial stone. Also, such compositions are widely used during construction and repair work in bathrooms, showers, when equipping fountains, showers and other things. Acrylic resin becomes hard quickly. The material is less toxic than the previously listed compounds.
Acrylic resins are used as an independent material or in the manufacture of other compounds. They add sand, marble chips, as well as various pigments. Therefore, acrylic can have a variety of shades. No more than 50% of additional components can be added to this resin.
Acrylic requires hardener. After the polymerization process, the composition is completely non-porous, which significantly improves performance. This greatly expands the scope of the material. Due to the absence of pores in the composition, the product will not be painted when coloring substances get on the surface. If the tabletop is made of acrylic, the beet juice will not leave a mark on it. The material is able to withstand heat up to 70 º. Molds for the manufacture of such products are made of gypsum, silicone or glass.
Polyethylene, polypropylene, polyvinyl chloride resins
If we compare natural and synthetic resins , the latter have much more positive operational qualities. This category includes many other varieties of formulations.
Often in modern industry, polyethylene resins are made and used. They have high indicators of flexibility, which is maintained even with a significant decrease in temperature (up to -60 º). Materials made of polyethylene resins are waterproof, not subject to the negative effects of aggressive chemicals. Therefore, the presented variety of resins is used to create a waterproofing film, as well as plumbing communications. Pipelines for chemically active substances, as well as items for medical, sanitary and hygienic equipment, are made from polyethylene resins.
Another popular variety today is polypropylene resins. They are obtained during the polymerization of propylene. This is gas that is obtained in the process of cracking refined products. Pipes, decorative materials, gas impermeable films, and parts for chemical equipment are made from polypropylene based on synthetic resins.
Another type of resin known in modern industry is polyvinyl chloride. It is obtained during polymerization. In the process, vinyl chloride is used - a gas that smells of ether and has no color.
Polyvinyl chloride resin is produced in the form of granules. The material is resistant to high temperatures, does not lose its qualities in the cold. It also has dielectric properties. This material is widely used for the production of waterproofing, linoleum, films for suspended ceilings, decorative materials, etc.
Polyisobutyl, Polystyrene, Vinyl Acetate
Polyisobutyl resins, which are obtained in the process of polymerization at a temperature of about 100 º, are widely used by modern industry. This material resembles rubber in appearance. It is elastic and is used as an anti-corrosion component. It does not allow water to pass through, therefore metal surfaces are reliably protected from oxidative reactions. Polyisobutylene is used to make varnishes and mastics.
Polystyrene synthetic resins are prepared using a polymerization process. The result is a colorless resin, which is used for the production of enamels, latex, as well as waterproofing films. Thermal insulation materials are also created from the polymer.
Polyvinyl acetate resins are polymers made from an ester of acetic acid and vinyl alcohol. It is a colorless liquid characterized by high mobility.
The material is not resistant to alkalis and acids. Polyvinyl acetate swells weakly in water. It is soluble in esters and alcohols, as well as in aromatic hydrocarbons.
The material allows you to create a strong connection of stone, glass. Therefore, polyvinyl acetate is widely used in the manufacture of varnishes and adhesives. For interior decoration of the building, these materials are also widely used.
Polyacrylate Resins
Polyacrylate compounds are produced on the basis of acrylic resin, adding methacrylic acid in the production. This is a glassy transparent mass, which is used in the production of various films, solutions. For example, a material is created from polyacrylate, which concrete is coated to give it water-repellent qualities. Also, various primers for internal work are made from it.
Polycondensation polymers are produced in a special way. In the course of such a process, a high molecular weight substance is formed by combining a significant number of molecules of the same type or of different types. To do this, low molecular weight components are mixed. The reaction occurs with the release of water, ammonia, hydrogen chloride.
Formaldehyde group
When considering varieties of synthetic resins, it is also worth paying attention to the formaldehyde group. One of these substances is phenol formaldehyde. This resin is obtained by combining various phenols and formaldehyde.
The result is a substance characterized by high strength, resistance to high temperatures. This material is used in the manufacture of fiberboards, chipboards. He also participates in the production of laminate, adhesives, mastics, varnishes.
The most well-known materials based on phenol-formaldehyde resins are bakelite varnish, polymer B. This material allows you to create coatings resistant to chemicals, used during hot gluing of asbestos cement, when bonding various building materials.
Amino-formaldehyde compositions are obtained by polycondensation of melamine and formaldehyde with urea. In this case, strictly regulated conditions are created. The result is a colorless substance that is relatively inexpensive. It is used to create thermal insulation, adhesives and laminate.
Polyurethane Resins
Polyurethane resins are crystalline type polymers. They are characterized by high melting qualities. These resins are obtained in the reaction of diisocnanates and polyols. The substance melts at low temperature, has a slight hygroscopicity. Polyurethane resin is resistant to atmospheric agents, oxygen, ozone, as well as alkalis and acids.
Polyurethanes are used to create adhesives. They are used for gluing stone slabs and other building materials.
Many polymers are used in the construction, woodworking, engineering and other sectors of modern production. They possess the required qualities, creating durable, durable joints, waterproof coatings.