Synthetic resin

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Vinyl ester resin is an example of a synthetic resin. MethmethacrylateBPA-glyc.png
Vinyl ester resin is an example of a synthetic resin.

Synthetic resins are industrially produced resins, typically viscous substances that convert into rigid polymers by the process of curing. In order to undergo curing, resins typically contain reactive end groups, [2] such as acrylates or epoxides. Some synthetic resins have properties similar to natural plant resins, but many do not. [3]

Contents

Synthetic resins are of several classes. Some are manufactured by esterification of organic compounds. Some are thermosetting plastics in which the term "resin" is loosely applied to the reactant(s), the product, or both. "Resin" may be applied to one of two monomers in a copolymer, the other being called a "hardener", as in epoxy resins. For thermosetting plastics that require only one monomer, the monomer compound is the "resin". For example, liquid methyl methacrylate is often called the "resin" or "casting resin" while in the liquid state, before it polymerizes and "sets". After setting, the resulting poly(methyl methacrylate) (PMMA) is often renamed "acrylic glass" or "acrylic". (This is the same material called Plexiglas and Lucite).

Types

The classic variety is epoxy resin, manufactured through polymerization-polyaddition or polycondensation reactions, used as a thermoset polymer for adhesives and composites. [4] Epoxy resin is two times stronger than concrete, seamless, and waterproof.[ citation needed ] Accordingly, it has been mainly in use for industrial flooring purposes since the 1960s. Since 2000, however, epoxy and polyurethane resins are used in interiors as well, mainly in Western Europe.

Synthetic casting "resin" for embedding display objects in Plexiglas/Lucite (PMMA) is simply methyl methacrylate liquid, into which a polymerization catalyst is added and mixed, causing it to "set" (polymerize). The polymerization creates a block of PMMA plastic ("acrylic glass") which holds the display object inside a transparent block.

Another synthetic polymer, sometimes called by the same general category, is acetal resin. By contrast with the other synthetics, however, it has a simple chain structure with the repeat unit of form −[CH2O]−.

Ion-exchange resins are used in water purification and catalysis of organic reactions. (See also AT-10 resin , melamine resin .) Certain ion-exchange resins are also used pharmaceutically as bile acid sequestrants, mainly as hypolipidemic agents, although they may be used for purposes other than lowering cholesterol.

Solvent impregnated resins (SIRs) are porous resin particles which contain an additional liquid extractant inside the porous matrix. The contained extractant is supposed to enhance the capacity of the resin particles.

A large category of resins, which constitutes 75% of resins used,[ citation needed ] is that of the unsaturated polyester resins.

The production of PVC entails the production of "vinyl chloride resins", which differ in the degree of polymerization. [5]

Silicone resins

Silicone resins are silicone-based polymers that exhibit various useful properties like weatherability (durability), dielectricity, water repellency, thermal stability, and chemical inertness. [6]

Health hazards

Health hazards potentially associated with synthetic resins are typically less of a concern than the hazards associated with the cured products, which are more commonly in contact with consumers. Issues of interest include the effects of unconsumed monomers, oligomers, and solvent carriers.

Dental restorative materials based on bis-GMA-containing resins [7] can break down into or be contaminated with the related compound bisphenol A, a potential endocrine disruptor. However, no negative health effects of bis-GMA use in dental resins have been found. [8] [9]

See also

Related Research Articles

<span class="mw-page-title-main">Poly(methyl methacrylate)</span> Transparent thermoplastic, commonly called acrylic

Poly(methyl methacrylate) (PMMA) is the synthetic polymer derived from methyl methacrylate. It is used as an engineering plastic, and it is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Hesalite, Plexiglas, Acrylite, Lucite, and Perspex, among several others. This plastic is often used in sheet form as a lightweight or shatter-resistant alternative to glass. It can also be used as a casting resin, in inks and coatings, and for many other purposes.

Acrylates are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion CH2=CHCO−2. Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acrylates contain vinyl groups. These compounds are of interest because they are bifunctional: the vinyl group is susceptible to polymerization and the carboxylate group carries myriad functionalities.

<span class="mw-page-title-main">Methyl isobutyl ketone</span> Chemical compound

Methyl isobutyl ketone (MIBK) is the common name for the organic compound 4-methylpentan-2-one, condensed chemical formula (CH3)2CHCH2C(O)CH3. This colourless liquid, a ketone, is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose.

Vinyl ester resin, or often just vinyl ester, is a resin produced by the esterification of an epoxy resin with acrylic or methacrylic acids. The "vinyl" groups refer to these ester substituents, which are prone to polymerize and thus an inhibitor is usually added. The diester product is then dissolved in a reactive solvent, such as styrene, to approximately 35–45 percent content by weight. Polymerization is initiated by free radicals, which are generated by UV-irradiation or peroxides.

<span class="mw-page-title-main">Poly(methyl acrylate)</span> Chemical compound

Poly(methyl acrylate) (PMA) is a family of organic polymers with the formula (CH2CHCO2CH3)n. It is a synthetic acrylate polymer derived from methyl acrylate monomer. The polymers are colorless. This homopolymer is far less important than copolymers derived from methyl acrylate and other monomers. PMA is softer than polymethyl methacrylate (PMMA), It is tough, leathery, and flexible.

<span class="mw-page-title-main">Acrylate polymer</span> Group of polymers prepared from acrylate monomers

An acrylate polymer is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.

<span class="mw-page-title-main">Methacrylic acid</span> Chemical compound

Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)COOH. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).

<span class="mw-page-title-main">Acrylic resin</span> Thermoplastic or thermosetting plastic

An acrylic resin is a thermoplastic or thermosetting plastic substance typically derived from acrylic acid, methacrylic acid and acrylate monomers such as butyl acrylate and methacrylate monomers such as methyl methacrylate. Thermoplastic acrylics designate a group of acrylic resins typically containing both a high molecular weight and a high glass transition temperature which exhibit lacquer dry capability. Acrylic resins designed for use in two component systems for crosslinking with isocyanate are referred to as polyols and are made with the monomers previously mentioned as well as hydroxy monomers such as hydroxy ethyl methacrylate. Acrylic resins are produced in different liquid carriers such as a hydrocarbon solvent or water in which case they are referred to as emulsions or dispersions and they are also provided in 100% solids bead form.

<span class="mw-page-title-main">Epichlorohydrin</span> Chemical compound

Epichlorohydrin is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar organic solvents. It is a chiral molecule generally existing as a racemic mixture of right-handed and left-handed enantiomers. Epichlorohydrin is a highly reactive electrophilic compound and is used in the production of glycerol, plastics, epoxy glues and resins, epoxy diluents and elastomers.

Curing is a chemical process employed in polymer chemistry and process engineering that produces the toughening or hardening of a polymer material by cross-linking of polymer chains. Even if it is strongly associated with the production of thermosetting polymers, the term "curing" can be used for all the processes where a solid product is obtained from a liquid solution, such as with PVC plastisols.

In polymer chemistry, a comonomer refers to a polymerizable precursor to a copolymer aside from the principal monomer. In some cases, only small amounts of a comonomer are employed, in other cases substantial amounts of comonomers are used. Furthermore, in some cases, the comonomers are statistically incorporated within the polymer chain, whereas in other cases, they aggregate. The distribution of comonomers is referred to as the "blockiness" of a copolymer.

<span class="mw-page-title-main">Methyl cyanoacrylate</span> Chemical compound

Methyl cyanoacrylate (MCA) is an organic compound that contains several functional groups: a methyl ester, a nitrile, and an alkene. It is a colorless liquid with low viscosity. Its chief use is as the main component of cyanoacrylate glues. It can be encountered under many trade names. Methyl cyanoacrylate is less commonly encountered than ethyl cyanoacrylate.

Resin casting is a method of plastic casting where a mold is filled with a liquid synthetic resin, which then hardens. It is primarily used for small-scale production like industrial prototypes and dentistry. It can be done by amateur hobbyists with little initial investment, and is used in the production of collectible toys, models and figures, as well as small-scale jewellery production.

<span class="mw-page-title-main">Bisphenol A diglycidyl ether</span> Chemical compound

Bisphenol A diglycidyl ether is an organic compound and is a liquid epoxy resin. The compound is a colorless viscous liquid. It is a key component of many epoxy resin formulations. Addition of further Bisphenol A and a catalyst and heat can produce Bisphenol A glycidyl ether epoxy resins of higher molecular weight that are solid.

<span class="mw-page-title-main">Methyl 2-chloroacrylate</span> Chemical compound

Methyl 2-chloroacrylate is a colorless liquid used in manufacture of acrylic high polymer similar to polymethylmethacrylate. It is also used as a monomer for certain specialty polymers.

<span class="mw-page-title-main">Ethyl vinyl ether</span> Chemical compound

Ethyl vinyl ether is an organic compound with the chemical formula CH3CH2OCH=CH2. It is the simplest enol ether that is liquid at room temperature. It is used as a synthetic building block and a monomer.

<span class="mw-page-title-main">Butyl methacrylate</span> Chemical compound

Butyl methacrylate is the organic compound with the formula C4H9O2CC(CH3)=CH2. A colorless liquid, it is a common monomer for the preparation of methacrylate polymers. It is typically polymerized under free-radical conditions.

<span class="mw-page-title-main">Ethyl methacrylate</span> Organic compound

Ethyl methacrylate is the organic compound with the formula C2H5O2CC(CH3)=CH2. A colorless liquid, it is a common monomer for the preparation of acrylate polymers. It is typically polymerized under free-radical conditions.

1,6-Hexanediol diacrylate is a difunctional acrylate ester monomer used in the manufacture of polymers. It is particularly useful for use in ultraviolet light cure applications. Furthermore, it is also used in adhesives, sealants, alkyd coatings, elastomers, photopolymers, and inks for improved adhesion, hardness, abrasion and heat resistance. Like other acrylate monomers it is usually supplied with a radical inhibitor such as hydroquinone added.

<span class="mw-page-title-main">Hydroxyethyl acrylate</span> Organic chemical-monomer

Hydroxyethyl acrylate is an organic chemical and a aliphatic compound. It has the formula C5H8O3 and the CAS Registry Number 818-61-1. It is REACH registered with an EU number of 212-454-9. It has dual functionality containing a polymerizable acrylic group and a terminal hydroxy group. It is used to make emulsion polymers along with other monomers and the resultant resins are used in coatings, sealants, adhesives and elastomers and other applications.

References

  1. Pham, Ha Q.; Marks, Maurice J. (2012). "Epoxy Resins". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a09_547.pub2.
  2. Chemistry, International Union of Pure and Applied. IUPAC Compendium of Chemical Terminology. doi:10.1351/goldbook.RT07166.{{cite book}}: |website= ignored (help)
  3. Collin, Gerd; et al. (2005). "Resins, Synthetic". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_089.
  4. Gurit Services AG. "5.1.3 Epoxy Resins". Guide to Composites (PDF). p. 19. Retrieved 2022-10-21.{{cite book}}: |website= ignored (help)
  5. Allsopp, M. W.; Vianello, G. (2012). "Poly(Vinyl Chloride". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a21_717.
  6. Silicone resins, shinetsusilicone
  7. Robert G. Craig; Dieter Welker; Josef Rothaut; Klaus Georg Krumbholz; Klaus-Peter Stefan; Klaus Dermann; Hans-Joachim Rehberg; Gertraute Franz; Klaus Martin Lehmann (2006). "Dental Materials". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_251.pub2.
  8. Soderholm KJ, Mariotti A (February 1999). "Bis-GMA–based resins in dentistry: are they safe?". The Journal of the American Dental Association. 130 (2): 201–209. doi:10.14219/jada.archive.1999.0169. PMID   10036843.
  9. Ahovuo-Saloranta, Anneli; Forss, Helena; Walsh, Tanya; Nordblad, Anne; Mäkelä, Marjukka; Worthington, Helen V. (31 July 2017). "Pit and fissure sealants for preventing dental decay in permanent teeth". The Cochrane Database of Systematic Reviews. 2017 (7): CD001830. doi:10.1002/14651858.CD001830.pub5. ISSN   1469-493X. PMC   6483295 . PMID   28759120.