Permission for the use of polyester resin in food. Polyester resins - what is it? Application, features of production technology. Production of polyester resins.
Epoxy and polyester resins are thermosetting, due to this quality, they are not able to return to liquid state after freezing. Both compositions are made in liquid form, but are capable of possessing different properties.
What is epoxy resin?
Epoxy type resin is of synthetic origin, it is not used in pure form, for solidification, a special agent is added, that is, a hardener.
This is how we can correctly determine your molecular weight. The morphology of polymers includes the arrangement, shape, size, and effect of a crystal in a solid polymer. This morphology is important because of its effect on the final properties of the solid polymer. Amorphous: These are those that do not have the ability to crystallize, being amorphous without any thermal conditions or history.
Semi-crystalline: commonly referred to as crystalline polymers, are polymers formed by amorphous regions and crystalline regions. The amorphous region is characterized by the complete decomposition of molecules, in contrast to the crystalline regions, in which the segments of molecular chains are elongated, orderly ordering, forming a common packing called a crystallite. Generally, polymers are never 100% crystalline.
When combining epoxy resin with a hardener, strong and solid products are obtained. Resin epoxy type is resistant to aggressive elements, they are able to dissolve when acetone enters. Cured epoxy resin products are distinguished by the fact that they do not emit toxic elements, and shrinkage is minimal.
In certain areas, segments of molecular chains are perfectly ordered, forming crystalline regions, while in other segments of the same molecules, they are disordered, which corresponds to amorphous regions. Therefore, the molecule is much larger than the length of the crystallite. From the proportion of crystalline regions - the type and size of crystals - the orientation of molecular chains and crystals.
Thermal crystallization and - Strain-induced crystallization. Due to the greater packing of molecules, crystallization increases the density and reduces the volume of the resulting solid. final characteristics of the product. While it is widely used around the world for packaging, in particular carbonated drinks, it has several other utilities that can be found in various market segments.
The advantages of epoxy resin are low shrinkage, resistance to moisture and wear, and increased strength. The solidification of the resin occurs at temperatures from -10 to +200 degrees.
Epoxy type resin can be hot cured or cold cured. With the cold method, the material is used on the farm, or in such enterprises where there is no possibility heat treatment. hot way used for the manufacture of high-strength products that can withstand heavy loads.
High efficiency mechanical strength, gloss and transparency makes this thermoplastic the preferred choice for many industries. Reduced waste of products and packaging - as they do not break even after significant falls. Extreme reduction of emissions during transportation.
Read it cool it might help you
But he also has epoxy resin, which is a much more expensive resin. Below is an image of an epoxy with a built-in bee. Crystalline polyester resin has almost the same appearance. So next: a polyester crystal smells strong, but the price is affordable. Once the orgonite is ready, the smell will end in about 2-3 days. Epoxy does not smell, but it takes about 24 hours to cure.
The working time for an epoxy type resin is up to one hour, since then the composition will begin to harden and become unusable.
Epoxy Resin Application
Epoxy resin serves as a quality adhesive material. It is able to bond wood, aluminum or steel, and other non-porous surfaces.
Other types of resin that can be used to make orgonite but you can't see anything inside the piece. Below we have fiberglass resin, a resin much more liquid with a strong smell but very functional to make organic parts. This is a type of resin that, when cured, presses very strongly and quickly, even more than crystal resin. We also have green resin which is a bit thick but also very effective.
This question is very specific, some prefer to use a denser resin and others a more fluid one. Important detail is that resin, when very dense, tends to create a lot air bubbles and thereby violate the aesthetics of orgonite. The manufacturer recommends using 10 drops for every 100 ml. But he doesn't mention the temperature environment where the piece will be made. Because it affects and a lot in the work. This is used for polyester resins. For those who use epoxy, you should ask the seller how to use it.
Epoxy-type resin is used to impregnate fiberglass; this material is used in the automotive and aviation industries, electronics, and in the manufacture of fiberglass for construction. Epoxy resin can serve waterproofing coating for floors or walls high humidity. Coatings are resistant to aggressive environments, so the material can be used for finishing external walls.
Yes, you can use combinations of crystals other than quartz or even without quartz. For example: combine black jasper tourmaline into orgonite to work on the main chakra. Obviously using a quartz crystal together will strengthen the piece. The piezoelectric effect can only be obtained with two stones: quartz and black tourmaline. No other stone has yet been discovered to produce this.
The effect occurs when these crystals are subjected to mechanical pressure, releasing an electrical charge. But what adds this effect to the game? The energy of transmutation will be carried out more intensely and quickly. The piece will become more powerful, as if it were turbocharged.
After solidification, a durable and hard product is obtained, which can be easily polished. Fiberglass products are made from such material, they are used in the economy, industry, and as room decor.
There are several types of metals that can be used in the construction of parts. We list some of them: copper, aluminum, iron, brass, bronze, gold, stainless steel, silver, etc. Each metal operates at a specific frequency of energy. It not only leads, but also reflects energy.
And the question of 50% metal, 50% crystal and resin? I like to apply a little more stones than metals. What is the difference between thermoplastics and thermosets? Among the many types of plastics divided into several families, we can divide them into two categories: thermoplastic and thermoset. Because some plastics fall into two categories depending on the modifications made to the original chemical structure.
What is polyester resin?
The basis of this type of resin is polyester; solvents, accelerators or inhibitors are used to solidify the material. The composition of the resin has various properties. It depends on the environment in which the material is used. Frozen surfaces are treated special formulations, which serve as protection against moisture and ultraviolet radiation. This increases the strength of the coating.
Thermoreactors, thermoset thermostats. These are curing resins that are widely used in crafts such as resin-on-polyester or small maintenance in civil engineering such as epoxy. After polymerization and hardening, this resin does not return to its original state, that is, it does not soften even when heated - this is the so-called "curing", trying to heat the thermoset material in order to fuse it will inevitably lead to degradation.
Treatment is irreversible chemical reaction called reticulation, also known as cross-linking; And occurs more easily and quickly in the presence of heat and can also occur when room temperature. It should be noted that this type of reaction is exothermic, therefore, even at room temperature, heating of the plastic material occurs naturally.
Polyester-type resin has low physical and mechanical properties compared to epoxy material, and is also characterized by low cost, due to which it is actively in demand.
Polyester resin is used in construction, mechanical engineering, and the chemical industry. When combining resin and glass materials, the product hardens and becomes durable. This allows you to use the tool for the manufacture of fiberglass products, that is, canopies, roofs, shower cubicles and others. Also, polyester resin is added to the composition in the manufacture of artificial stone.
In the figure below, you can see an example of the polymerization reaction of a styrene-polyester copolymer used in craftsmanship. Thermoreactors, as well as thermoplastics, can be reinforced with fibers and loaded with other fillers. They are quite rigid even without the addition of reinforcements, but this is a story about glass: the harder, the more fragile; This allows them to be used in more specific applications, such as when thermoplastics cannot withstand heat and in purely hand-held work applications.
In addition, the fact that the thermoset cannot be recycled adds another disadvantage: waste destined for the production of charges in powder form. Unlike thermosets, thermoplastics do not cure and can easily melt with heat and cure again when cooled at room temperature. They can be recycled several times, but obviously they lose their properties at each stage of processing and can also deteriorate due to a large number of recycles.
The surface treated with polyester resin needs additional coating; for this, a special gelcoat agent is used. The type of this tool is selected depending on the coverage. When using polyester resin indoors, when moisture and aggressive substances do not get on the surface, orthophthalic gelcoats are used. At high humidity, use isophthalic-neopentyl or isophthalic agents. Gelcoats are also available with different qualities, they can be resistant to fire or chemicals.
Compared to thermosets, they have much lower thermal and dimensional stability, but are much easier and more economical to process. Below is a table with examples of the main families of polymers, thermoplastics and thermosets, their most well-known trade names and manufacturing companies.
It is presented as a crystalline powder, white, non-hygroscopic, odorless, sparingly soluble in water, alcohols, insoluble in benzene, carbon tetrachloride. Pentaerythritol contains the structure, four methylol groups are symmetrically arranged around a central atom. Heat melting compound, its low solubility and high reactivity The four hydroxyl groups are functions of the compact and symmetrical structure of the molecule. Structural configuration and functionality of pentaerythritol, containing four primary hydroxyl groups, the transformation from a single family member polyols, with ease of reaction and its derivatives, conferring greater resistance to heat, light and moisture.
The main advantages of polyester resin
Polyester resin, in contrast to the epoxy composition, is considered more in demand. It also has a number of positive qualities.
- The material is hard and chemical resistant.
- The resin has dielectric properties and wear resistance.
- When used, the material does not emit harmful elements, therefore it is safe for the environment and health.
A significant part of Pentaerythritol is used in the production of alkyd resins used in the composition of paints and varnishes, giving them increased adhesion, good speed drying, strength, resistance to moisture, heat and light, color stability and improved gloss. Pentaerythritol significantly improves the performance of tall oil esters, so varnishes made with these esters have a faster drying rate and greater water and alkali resistance. Pentaerythritol gives excellent results when used in the manufacture of these products, providing excellent drying properties in its handling and film properties.
When combined with glass materials, the agent has increased strength, even exceeding steel. For solidification, special conditions are not required, the process takes place at normal temperature.
Unlike epoxy, polyester resin has low cost, so coatings are cheaper. The polyester-type resin has already started the curing reaction, so if the material is old, then it may have a solid appearance, and is unsuitable for work.
Compared with natural oils Pentaerythritol esters polymerize and dry faster, resulting in harder and longer films. plasticizers and stabilizers. Especially used in vinyl compounds due to its excellent thermal stability and light aging.
Pentaerythritol is used in the manufacture of lubricants, especially those requiring high thermal stability, as an additive to prevent carbonation and to prevent corrosion of parts exposed to moisture. Ethers fatty acids pentaerythritol are also used as lubricants due to their resistance to high temperatures.
Polyester-type resin is easier to work with and the cost of the material saves on costs. But to get a more durable surface or high-quality bonding, epoxy material is used.
Differences between polyester and epoxy resin, which is better?
Each material has a number of advantages, and the choice depends on the purpose of the product used, that is, in what conditions it will be applied, the type of surface also plays an important role. Epoxy type resin has a higher cost than polyester material, but it is more durable. The adhesive property of epoxy exceeds any material in strength, this tool reliably connects various surfaces. Unlike polyester resin, the epoxy composition has less shrinkage, has high physical and mechanical properties, less moisture passes through, and is resistant to wear.
Pentaerythritol is used to produce pentaerythritol tetraethitrate. It is rarely used alone, however it is often used as a secondary solid explosive. Product specification information should be consulted with the Company's field of activity.
This is a question that often comes up when you go to a homemade or repair pool, car or boat. The resin has become very popular material, which only limits the creativity of whoever uses it. Epoxy usually costs 3-5 times more than polyester resin, so it would be a shame to use it when polyester resin is ideal. Here are 4 elements that should inform your decision.
But unlike the polyester composition, epoxy hardens more slowly, which leads to a slowdown in the manufacture of various products, such as fiberglass. Also, to work with epoxy requires experience or careful handling, further processing of the material is more difficult.
With exothermic curing, during the temperature increase, the material is able to lose viscosity, this makes it difficult to work. Basically, epoxy-type resin is used in the form of glue, as it has high adhesive qualities, unlike polyester material. In other cases, it is better to work with polyester-type resin, this will significantly reduce costs and simplify the work. When using epoxy-type resin, it is necessary to protect hands with gloves, and respiratory organs with a respirator, so that when using hardeners, you do not get burns.
To work with polyester-type resin, special knowledge and experience are not required, the material is easy to use, does not emit toxic elements, and is notable for its low cost. Polyester resin can be used to process various surfaces, but the coating needs additional processing special means. For bonding various materials polyester type resin is not suitable, it is better to use an epoxy mixture. Also for making products decorative look it is better to use epoxy resin, it has high mechanical performance, and is more durable.
Much less catalyst is required to make a compound from polyester resin, which also helps to save money. Dries polyester compound faster than epoxy material within three hours, ready product has elasticity or increased flexural strength. The main disadvantage of polyester material is its combustibility, due to the content of styrene in it.
Polyester resin must not be applied on top of epoxy. If the product is made or patched with epoxy resin, then in the future it is better to use it for restoration. A polyester-type resin, unlike an epoxy composition, can shrink significantly, it must be done immediately all the work in two hours, otherwise the material will harden.
How to properly prepare the surface for processing?
In order for the resin to adhere well, the surface must be properly treated, such actions are performed using an epoxy and polyester composition.
First, degreasing is performed, for this, various solvents are used or detergent formulations. The surface should not have greasy spots or other contaminants.
After that, grinding is performed, that is, they are removed upper layer, with a small area, use sandpaper. For surfaces large sizes use special grinding machines. Dust is removed from the surface with a vacuum cleaner.
During the manufacture of fiberglass products or when re-applying the agent, the previous layer is covered with resin, which has not had time to completely harden and has a sticky surface.
Results
Polyester resin is much easier to work with, this material helps to save on costs, as it has a low cost, it quickly hardens, and does not need complex processing. Epoxy-type resin is characterized by high strength, adhesive ability, and is used when casting individual products. When working with it, you must be careful, further processing is more difficult. During work with such compounds, it is necessary to protect the hands and respiratory organs with special means.
Behind last years polyester resins have become very popular. First of all, they are in demand as leading components during the production of fiberglass, strong and lightweight.
Resin making: the first stage
Where does the production of polyester resins begin? This process begins with the distillation of oil - during this, various substances are released: benzene, ethylene and propylene. They are necessary for the production of antihydrides, polybasic acids, glycols. After cooking together, all these components create the so-called base resin, which at a certain stage must be diluted with styrene. The last substance, for example, can be 50% of finished products. As part of this stage, the sale of ready-made resin is also allowed, but the production stage is not yet completed: one should not forget about saturation with various additives. It is thanks to these components that the finished resin acquires its unique properties.
The composition of the mixture can be changed by the manufacturer - a lot depends on where exactly the polyester resin will be used. Specialists select the most optimal combinations, the result of such work will be substances with completely different properties. 
Resin production: second stage
It is important to ready mix was solid - they usually wait until the polymerization process reaches the end. If it is interrupted, and the material is on sale, it is only partially polymerized. If nothing is done with it, the polymerization will continue, the substance will definitely harden. For these reasons, the shelf life of the resin is very limited: than older material, the worse its final properties. Polymerization can also be slowed down - refrigerators are used for this, hardening does not occur there.
In order for the production stage to be completed, and it turned out to the resin, it is also necessary to add two important substances: catalyst and activator. Each of them performs its own function: heat generation begins in the mixture, which contributes to the polymerization process. That is, a heat source from the outside is not required - everything happens without it.
The course of the polymerization process is regulated - the proportions of the components are controlled. Since contact between the catalyst and the activator can result in an explosive mixture, the latter is usually added to the resin exclusively as part of the production, the catalyst is added before use, it is usually supplied separately. Only when the polymerization process is completely completed, the substance hardens, we can conclude that the production of polyester resins is completed. 
Initial resins
What is this material in its original state? It is a honey-like, viscous liquid that can range in color from dark brown to light yellow. When a certain amount of hardeners is introduced, the polyester resin first thickens slightly, then acquires a gelatinous state. A little later, the consistency resembles rubber, then the substance hardens (becomes infusible, insoluble).
Such a process is commonly called curing, since it takes several hours at ordinary temperature. When the resin is in the solid state, it resembles a rigid durable material, which is easy to color in the most different colors. As a rule, it is used in combination with glass fabrics (polyester fiberglass), it performs the function structural element for the manufacture of various products - such is polyester resin. Instructions when working with such mixtures are very important. It is necessary to comply with each of its points.
Main advantages
Polyester resins in the cured state are excellent construction materials. They are characterized by hardness, high strength, excellent dielectric properties, wear resistance, and chemical resistance. Do not forget that in the process of operation products made of polyester resin are safe from an environmental point of view. Certain mechanical qualities of mixtures that are used in conjunction with glass fabrics resemble parameters in their performance (in some cases they even exceed them). The manufacturing technology is cheap, simple, safe, since the substance cures at ordinary room temperature, even the application of pressure is not required. There is no emission of volatile or other by-products, only slight shrinkage is observed. Thus, in order to manufacture a product, expensive bulky installations are not needed, and there is no need for thermal energy, thanks to which enterprises quickly master both large-capacity and small-capacity production. Do not forget about the low cost of polyester resins - this figure is two times lower than that of epoxy counterparts.
Production growth
It cannot be overlooked that the this moment The production of unsaturated polyester resin is gaining momentum every year - this applies not only to our country, but also to general foreign trends. If you believe the opinion of experts, this situation will certainly continue in the foreseeable future.
Disadvantages of resins
Of course, polyester resins also have some disadvantages, like any other materials. For example, styrene is used as a solvent during production. It is flammable and highly toxic. At the moment, such brands have already been created that do not have styrene in their composition. Another obvious drawback: flammability. Unmodified, unsaturated polyester resins burn just like hardwoods. This problem is solved: powder fillers (low molecular organic compounds containing fluorine and chlorine, antimony trioxide), sometimes chemical modification is used - tetrachlorophthalic, chlorendic acid, some multimers are introduced: vinyl chloroacetate, chlorostyrene, and other compounds that contain chlorine. 
Resin composition
If we consider the composition of unsaturated polyester resins, here we can note a multicomponent mixture chemical elements different nature- each of them performs certain tasks. The main components are polyester resins, they perform different functions. For example, polyester is the main component. It is the product of a polycondensation reaction that reacts with anhydrides or polybasic acids.
If we talk about polyhydric alcohols, then diethylene glycol, ethylene glycol, glycerin, propylene glycol, dipropylene glycol are in demand here. As anhydrides, adipic, fumaric acids, phthalic and maleic anhydrides are used. The casting of polyester resin would hardly be possible if the polyester had a low molecular weight (about 2000) when ready for processing. In the process of molding products, it turns into a polymer with a three-dimensional network structure, high molecular weight (after curing initiators are introduced). It is this structure that provides chemical resistance, high strength of the material.
Solvent-monomer
Another essential component is the solvent monomer. In this case, the solvent performs a dual function. In the first case, it is required in order to reduce the viscosity of the resin to the level required for processing (because the polyester itself is too thick).
On the other hand, the monomer takes an active part in the process of copolymerization with polyester, due to which optimal speed polymerization and high depth of material curing (if we consider polyesters separately, their curing is quite slow). Hydroperoxide is the very component that is required to convert to a solid state from a liquid - this is the only way polyester resin acquires all its qualities. The use of a catalyst is also mandatory when working with unsaturated polyester resins.
Accelerator
This ingredient can be introduced into the composition of polyesters both during manufacture and when processing takes place (before the addition of the initiator). Cobalt salts (cobalt octoate, naphthenate) can be called the most optimal accelerators for polymer curing. Polymerization must not only be accelerated, but also activated, although in some cases it is slowed down. The secret is that if you do not use accelerators and initiators, they will form independently in the finished substance, due to which polymerization will occur prematurely - right during storage. To prevent such a phenomenon, one cannot do without a curing retarder (inhibitor).
The principle of the inhibitor
The mechanism of action of this component is as follows: it interacts with free radicals that periodically arise, resulting in the formation of low-active radicals or compounds that do not have a radical nature at all. The function of inhibitors is usually performed by such substances: quinones, tricresol, phenone, some of the organic acids. Inhibitors are introduced into the composition of polyesters in small quantities during manufacture.
Other additives
The components described above are the main ones, it is thanks to them that it is possible to work with polyester resin as a binder. However, as practice shows, in the process of molding products it is enough a large number of additives are introduced into polyesters, which, in turn, have a variety of functions, modify the properties of the original substance. Among these components, powder fillers can be noted - they are introduced specifically to reduce shrinkage, reduce the cost of the material, and increase fire resistance. It should also be noted glass fabrics (reinforcing fillers), the use of which is due to an increase in mechanical properties. There are other additives: stabilizers, plasticizers, dyes, etc. 
Glass mats
Both in thickness and in structure, fiberglass can be different. Glass mats are fiberglass that are chopped into small pieces, their length varies between 12-50 mm. The elements are glued together using another temporary binder, which is usually a powder or emulsion. polyester is used for the manufacture of glass mats, which consist of fibers arranged randomly, fiberglass is its own appearance looks like regular fabric. To achieve the maximum possible hardening, one should use different brands fiberglass.
In general, glass mats have less strength but they are much easier to handle. When compared with fiberglass, this material better repeats the shape of the matrix. Since the fibers are quite short, have a chaotic orientation, the mat can hardly boast of great strength. However, it can be very easily impregnated with resin, since it is soft, while being loose and thick, somewhat reminiscent of a sponge. The material is really soft and moldable. Laminate, for example, which is made from such mats, has excellent mechanical properties, has a high resistance to atmospheric conditions (even within a long period). 
Where are glass mats used?
The mat is used in the field of contact molding to be able to produce goods complex shapes. Products made from this material are used in a variety of areas:
- in the shipbuilding industry (construction of canoes, boats, yachts, fish cutters, various internal structures etc.);
- glass mat and polyester resin are used in the automotive industry ( various details machines, cylinders, vans, diffusers, tanks, information panels, housings, etc.);
- in the construction industry (certain elements wooden products, construction of bus stops, partition walls, etc.).
Glass mats have different density like the thickness. Divide the material according to the weight of one square meter, which is measured in grams. Meets Enough thin material, almost airy (glass veil), there is also a thick one, almost like a blanket (used in order for the product to acquire desired thickness, obtained the required strength).