Formaldehyde-free

Urea—formaldehyde use has been greatly restricted because of free formaldehyde (qv) emissions which can cause eye irritation and in some cases serious illness. Some attempts at developing formaldehyde-free urea-based materials are ongoing. 

Dihydroxyethyleneurea (DHEU) (6) is also a cross-linker, but is extremely vulnerable to hydrolysis in an alkaline home laundering. Another approach toward formaldehyde-free agents has been the use of glyoxal in the bridging group between cycHc DHEU and related ring systems (108). 

Neutral cleaners have a soap-type hydrotroping base, with additions of surfactant (to improve cleaning, wetting, penetration and defoaming), inhibitors (which may be nitrite or organic) and a bactericide. The bactericide was often formaldehyde, but this is now being superseded by formaldehyde-free materials, based on quaternary ammonium salts. 

They have many advantages, they are formaldehyde free, halogen free, demonstrate good thermal Figure 7 Phenoxyethanol stability and have good skin compatibility. However,... 

The polymers can be categorised as formaldehyde containing and formaldehyde free and as thermoset or thermoplastic resins. Typical formaldehyde containing resins are melamine formaldehyde sulfonamide resins, where the sulfonamide is ortho and para toluenesulfonamide. The sulfonamide, which is a solvent for the dye, undergoes a condensation polymerisation with formaldehyde and melamine, the latter acting as a cross-linking agent. Non-formaldehyde, thermoplastic resins are usually polyamides and polyesters. 

In 1868 Hofmann (7) reported the preparation of trithiane. This is the product obtained when the hydrogen sulfide-formaldehyde reaction is run under strongly acidic conditions. Under weakly acidic or mildly alkaline conditions, the product formed retains significant amounts of oxygen. Recently, Credali and Russo (8) have examined in depth the reaction of hydrogen sulfide with aqueous formaldehyde free of added acid or base. 

An estimate five (5) million pounds per year of hexamine are consumed to make commercial explosives. Hexamine demand from the phenolic resin segment has declined due to increased competition from formaldehyde-free resins and other resins that offer performance advantages. 

Li K, Geng X (2005) Formaldehyde-free wood adhesives from decayed wood. Macromol Rapid Commun 26 529-532... 

An equivalent quantity of aqueous formaldehyde free from methanol may be used. 

Professor Viswanathan of the University of Arkansas discusses his research into the formulation of formaldehyde-free, thermosetting adhesives from whey permeate with urea and phenol or both in Chapter 28. 

The use of formaldehyde-free adhesive resins from whey and whey byproducts for manufacturing construction-quality boards could resolve these problems simultaneously. The demand for formaldehyde-based thermosetting adhesive resins in the United States was estimated to be 1.9 billion pounds in 1983 (5). The anticipated requirement for resins and the potential availability of raw materials from whey are a fortuitous combination. 

Formaldehyde-free agents Polycarboxylic acid catalysis... 

The high-temperature cross-linking of cotton cellulose by polycarboxylic acids, having three to four carboxyls per molecule, has been extensively investigated as a method of formaldehyde-free durable-press finishing. In 1963, Gagliardi and Shippee [383] showed... 

Release of larger amounts of formaldehyde Formaldehyde-free or low formaldehyde finishes, selection of products and condensation conditions (better than formaldehyde scavengers and cheaper than washing with new drying)... 

This poor cost performance ratio is one reason for the relatively small market penetration by this formaldehyde-free finish. Another reason is that a completely formaldehyde-free finish is not as commercially important since the advent of the ultra low formaldehyde products. However, a 1 1 mixture of DMDHEU and DMeDHEU is popular because of its reduced formaldehyde levels with only slightly inferior physical properties at an acceptable cost. 

Geubtner M, Modern formaldehyde-free easy-care finishing for a handle in line with modem trends , Melliand Textilberichte, 1990, 71, 394—397, E180-E182. 

Welch C M, Formaldehyde-free durable-press finishes , view Progress Coloration, 1992,22,32--11. 

Gelabert A and Kyriazis J, APCM - a new type of formaldehyde-free crosslinking agents for wash-and-wear finishes , MeZZiawd/wtemafiowa/, 1999,5(2), 181-184 and (in German) Melliand Textilberichte, 1999, 80(1/2), 50-53. 

A range of self crosslinking formaldehyde free acrylic resins which impart different degrees of stiffness and improve fabric stability. Cured in a relatively short time above 150C to a wash resistant finish without catalyst. 

Formaldehyde-free agent for fixing dyes on cotton. 

Other collaborations like this one have produced a Dow product called Wood-stalk, a formaldehyde-free polyurethane resin particleboard from a harvested wheat straw fiber, a renewable resource. Dow acknowledges the importance of stakeholder collaboration in their business strategy. Green building practices... 

The furniture, laminate flooring and construction industries are principal users of melamine products. In 1998, Cytec (the 1993 chemicals specialty spin-off from American Cyanamid) in the US began the production of the first formaldehyde-free melamine resins... 

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