Melamine-formaldehyde resins applications

The term aminoplastics has been coined to cover a range of resinous polymers produced by interaction of amines or amides with aldehydes. Of the various polymers of this type that have been produced there are two of current commercial importance in the field of plastics, the urea-formaldehyde and the melamine-formaldehyde resins. There has in the past also been some commercial interest in aniline-formaldehyde resins and in systems containing thiourea but today these are of little or no importance. Melamine-phenol-formaldehyde resins have also been introduced for use in moulding powders, and benzoguanamine-based resins are used for surface coating applications. 

Melamine (I,3,5-triamino-2,4,6-triazine) was first prepared by Liebig in 1835. For a hundred years the material remained no more than a laboratory curiosity until Henkel patented the production of resins by condensation with formaldehyde. Today large quantities of melamine-formaldehyde resins are used in the manufacture of moulding compositions, laminates, adhesives, surface coatings and other applications. Although in many respects superior in properties to the urea-based resins they are also significantly more expensive. 

Good quality steel is used and electrozinc is preferred for washing machines. Steel is pretreated with iron phosphate for economy electrozinc with a fine crystal zinc phosphate. No primer is normally used 25-40/im of finish is applied direct to metal. The required properties are best obtained with a thermosetting acrylic or polyester/melamine-formaldehyde finish. Self-reactive acrylics are usually preferred these resins contain about 15 Vo 7V-butoxymethyl acrylamide (CH2=CH —CO —NH —CHj—O —C4H,) monomer and cure in a manner similar to butylated melamine-formaldehyde resins. Resistance or anti-corrosive properties may be upgraded by the inclusion of small amounts of epoxy resin. Application is usually by electrostatic spray application from disc or bell. Shapes are complex enough to require convected hot-air curing. Schedules of 20 min at 150-175°C are... 

Thermosets differ molecularly from thermoplastics in that their individual chains are anchored to one another through crosslinks. The resulting network creates cohesive materials that demonstrate better thermal stability, rigidity, and dimensional stability than thermoplastics. Some examples of traditional thermosets are melamine-formaldehyde resins, which are used to treat fabrics to make them wrinkle-free, and Bakelite (a phenol-formaldehyde resin), a historically important polymer used in many applications, such as costume jewelry, electrical switches, and radio casings. 

The industrial production and application of reactive and non-reactive microgels in organic coatings such as binders or components of binders, e.g. together with, e.g. acrylic and/or melamine/formaldehyde resins, especially for automotive coatings, was reported in a number of publications between 1980 and... 

Another use of urea is for resins, which are used in numerous applications including plastics, adhesives, moldings, laminates, plywood, particleboard, textiles, and coatings. Resins are organic liquid substances exuded from plants that harden on exposure to air. The term now includes numerous synthetically produced resins. Urea resins are thermosetting, which means they harden when heated, often with the aid of a catalyst. The polymerization of urea and formaldehyde produces urea-formaldehyde resins, which is the second most abundant use of urea. Urea is dehydrated to melamine, which, when combined with formaldehyde, produces melamine-formaldehyde resins (Figure 96.2). Melamine resins tend to be harder and more heat-resistant than urea-formaldehyde resins. Melamine received widespread attention as the primary pet food and animal feed contaminant causing numerous cat and dog deaths in early... 

Urea is used as a solid fertilizer, a liquid fertilizer and miscellaneous applications such as animal feed, urea, formaldehyde resins, melamine, and adhesives. Presently, the most popular nitrogen fertilizer is a urea-ammonium nitrate solution. Urea-formaldehyde resins have large use as a plywood adhesive. Melamine-formaldehyde resins are used as dinnerware and for extra-hard surfaces (Formica ). The melamine is synthesized by condensation of urea molecules. 

In certain cases the acidity Melamine Formaldehyde resins (MF resins) or alkaline Polyurethane (also known us PU) resin (PUR resin) and alkali hardener (epoxy resin) can corrode or even totally dissolve the metallic pigments. In case of bronze pigments a color shift is possible. For these applications special metallic pigments are recommended, which are protected by an organic or inorganic coatings [14]. 

Mineral fillers find application for melamine-formaldehyde resins, thus enabling compositions to be obtained with heat resistance in excess of 200 °C. 

Polycondensation adhesives (usually for industrial application) on the basis of phenol, resorcinol, urea and melamine formaldehyde resins. For the processing of such adhesives used, in particular, for wood constructions in moisture-loaded buildings, such as swimming pools, heatable presses are required. 

Before the advent of oxygenate ethers like MTBE, formaldehyde production was the largest single application of methanol, with at least 16 manufacturers and consuming over 30% of the methanol produced. Formaldehyde is used in the manufacture of urea-formaldehyde resins, phenol-formaldehyde resins, melamine-formaldehyde resins, acetal resins, acetylenic chemicals, etc. The reactions involved in formaldehyde synthesis are ... 

Phosphoric acid, or more commoifly ammonium chloride, is used as a hardener for UF resin adhesives. Ammonium chloride reacts with formaldehyde to produce hexamine and hydrochloric acid, and the latter catalyzes the curing of the resin. In the manufacture of plywood a resin (with U/F molar ratio typically 1 1.8) mixed with hardener is applied to wood veneers, which are then plied together and pressed at 95-110°C under a pressure of 200-800 psi (1.38-5.52 MPa). The UF resin-bonded plywood is suitable for indoor applications but is generally unsuitable for outdoor use. For outdoor applications phenol-formaldehyde, resorcinol-formaldehyde, or melamine-formaldehyde resins are more suitable. 

The presence of numerous hydroxyl groups able to react with formaldehyde makes starch-derived products suitable chemicals for formaldehyde-based resins. Research on this subject started many years ago and showed that in a number of applications it is possible to partially replace or extend urea formaldehyde, phenol formaldehyde and melamine formaldehyde resins without significantly affecting the finished product s performance. In many applications, adhesive systems based on formaldehyde resins incorporate a polysaccharide component. More than 4.5 Mio mto of formaldehyde-based resins have been produced in Western Europe alone. The use of carbohydrates allows lower consumption of oil-based resins and, consequently, reduced release of formaldehyde in the environment. 

Same as urea-formaldehyde resins, melamine-formaldehyde resins present a wide color range, are track and scratch resistant, possess good electrical properties and superior heat resistance and hardness. The resins excellent adhesive properties make them useful in the furniture industry. Due to fireedom fi-om color and the above mentioned properties, urea-formaldehyde resins are employed for laminating. Other applications depend on the nature of different fillers. Electrical applications demand mineral-filled urea-formaldehyde resins, whilst the cellulose-filled resins are used for manufacturing of clock cases and trays. Special applications include flame retardant agents [2]. 

Acid catalysts n. Acids which may be either organic or inorganic, or salts from these acids which exhibit acidic characteristics. They are used to promote or accelerate chemical reactions, and find special applications in the manufacture and subsequent hardening of synthetic resins. Acid catalysts have been employed in the manufacture of polymerized drying oils, coumarone, urea, phenol-and melamine-formaldehyde resins, and in the cold-setting of compositions containing the last three named resins. Odian GC... 

The application of lignocellulosic fibres in reinforcing plastics has been known for a long time. As early as 1908 the first composite materials were applied for the production of large quantities of sheets, tubes and pipes for electronic purposes (paper or cotton to reinforce sheets, made of phenol or melamine formaldehyde resins). In 1896, aeroplane seats and fuel tanks were made of natural fibres with a small amount of polymeric binder [1],... 

A considerable number of microcapsules intended for textile applications are fabricated using melamine-formaldehyde resin. The reason for this is its superior performance, including high hardness and mechanical robustness, excellent heat resistance, water resistance, outdoor weatherability, and unlimited colorability (Fei et al., 2015). Properties of polymer wall material should be carefully considered when opting for the best embedding method and choice of a compatible binder. Salaiin et al. (2009) investigated the adhesive properties of microcapsule wall material, melamine... 

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