Formaldehyde release adhesives

Well over 95 percent of the hardwood plywood production in the United States uses urea-formaldehyde as the adhesive bonding agent between veneers for reasons of quality, intended use and economics. In this industry, formaldehyde evolution is a subject of concern because normally all of the adhesive formaldehyde released under elevated temperatures is not tied up in the set glue line. This is an area that is of real concern to the particleboard industry which uses urea-formaldehyde as its binder. 

Table 3 shows the test results for various properties. Even though the density of the chip form material is three times that of lauan plywood, the separation strength, warping strength, and nail withdrawal resistance properties were all found to be about the same as for the lauan plywood. Also the amount of formaldehyde released (the amount of vaporized formalin, a solvent used in the adhesive), was found to be less than 1/40 of the amount released by the lauan plywood. 

Formaldehyde Release from Wood Panel Products Bonded with Phenol Formaldehyde Adhesives... 

HIS BOOK SUMMARIZES OUR CURRENT UNDERSTANDING of many problems related to measuring, abating, and understanding formaldehyde emission from wood products bonded with formaldehyde-based adhesive resins. It contains expanded and updated versions of selected papers presented at an ACS symposium, Formaldehyde Release from Cellulose in Wood Products and Textiles. In addition, three chapters from participants who could not attend the meeting were added. 

NB. [Angus] 2-Nitro-l-butanol chemical and pharmaceutical intermediate, in tire cord adhesives, as formaldehyde release agents, deodorant antimicrobials. 

AI3-02258 EINECS 200-957-6 HSDB 5213 2-Methyl-2-nitropropanol 2-Methyl-2-nitropropan-1-ol 2-Methyl-2-nitro-1-propanol 2-Nitro-2-methyl-1-propanol 2-Nitro-2-methylpropanol NMP NMP Cone, NSC 17676 1-Propanol, 2-methyl-2-nltro-, Chemical and pharm-aceutioal intermediate, in tire cord adhesives, as formaldehyde release agents, deodorants, antimicrobials. Chemical intermediate, formaldehyde donor, textile reactant reduces formaldehyde on finished cloth. Solid mp = 89.5° bp ° = 94° Xm = 278 nm (MeOH) slightly soluble in H2O, soluble in organic solvents. Sigma-Aldrich Fine Chem. Whittaker dark Daniels. 

Formaldehyde is generally the aldehyde used in the preparation, setting, and curing of tannin adhesives. It is normally added to the tannin extract solution at the required pH, preferably in its polymeric form of paraformaldehyde, which is capable of fairly rapid depolymerization under alkaline conditions, and as urea-formalin concentrates. Hexamethylenetetramine (hexamine) may also be added to resins due to its potential formaldehyde releasing action under heat. Hexamine is, however, unstable in acid media [24] but becomes more stable with increased pH values. Hence under alkaline conditions the liberation of formaldehyde might not be as rapid and as efficient as wanted. Also, it has been fairly widely reported, with a few notable exceptions [25], that bonds formed with hexamine as hardener are not as boil resistant [26] as those formed by paraformaldehyde. The reaction of formaldehyde with tannins may be controlled by the... 

Chem. Descrip. Benzylhemiformal CAS 14548-60-8 EINECS/ELINCS 238-588-8 Uses Formaldehyde releaser, preservative, bactericide, fungicide, yeast inhibitor in aq. coatings, polymer disps., filler suspensions, slurries, sol ns. and disps. of adhesives and thickeners, concrete additives, metalworking fluids, cleaners... 

Uses Antimicrobial, preservative, stabilizer, slimicide for use in latexes, emulsion paint, aq. slurries, adhesives, tape Joint compds., o/w emulsions, paper coatings, pesticides, water-based inks, hides and skins USDA approved for paints used in federally inspected plants and packing adhesives having min. contact with meat or poultry food prods. food pkg. adhesives, paper food-contact slimicide Features Inhibitor of bacteria, yeast, and fungi heat-stable, low corrosivity no formaldehyde released... 

Uses Release agent lubricant blocking agent chemical intermediate coupling agent in acrylic, epoxy, polyamide, polyether, silicone, vinyl polymers, cellulosics, furan, melamine, nitrocellulose, PU, polyvinyl butyral, and urea-formaldehyde, for adhesives, coatings, filler treatment, foundry, inks, rubber, sealants, and textile applies. Manuf./Distrib. ABCR AP Resources Alfa Aesar Chisso Am. Fluka Gelest Silar Labs TCI Am. United Chem. Tech. 

Precaution Combustible Uses Organic synthesis chemical and pharmaceutical intermediate in tire cord adhesives as formaldehyde release agents deodorants antimicrobials Trade Name Synonyms NB [ANGUS http //WWW. dow. com/angus/ ... 

Uses Antimicrobial, preservative in adhesives, latex emulsions, paints, cutting fluids, topical pharmaceuticals preservative In cosmetics, food-pkg. adhesives, food-contact PU resins preservative for pigment slurries and latexes used as pigment binders in food-contact paper/paperboard Features Formaldehyde-releasing Use Level 0.02-03% 0.02% (topicals)... 

Uses formaldehyde-releasing preservative in hand creams, lotions, face creams, shampoos, latex paints, topical medicaments, polishes, metal-working fluids, adhesives, inks, etc. quaternium-15. QUATERNIUM-15 A... 

In practice, the most critical raw material might be the water, espeeially if dwell water is used or water purification units are not well maintained. Polymer dispersions should be observed while stored in tanks. Overlay by an approx. 1 to 2% preservative solution containing a formaldehyde releaser to protect condense water via the gas phase is a very efficient measurement to keep the polymer dispersions and the tank in good condition. The same procedure helps to keep fresh finished goods, while stored in tanks. A lot of good ideas can be transfered from other industries producing water based materials, like e.g. cosmetics, food, adhesives (Wallhaeusser, 1995). 

The microbicide is recommended for use as an industrial preservative for the protection of water-based functional fluids with pH values > 7 such as latex paints, resin emulsions, adhesives, pigment slurries, concrete additives, metalworking fluids. Its compatibility with protein containing formulations is very limited. Normal use levels range between 0.1 and 0.3%. The spectrum of efficacy (see Table 31) covers above all bacteria as is characteristic for a formaldehyde releasing compound. 

Aeeordingly N-(2-hydroxypropyl)-aminomethanol can be used for the in-ean preservation of a great variety of aqueous produets such as adhesives, bitumen emulsions, metalworking fluids. However, one has to keep in mind that formaldehyde releasing eompounds are not in any case compatible with protein-based (e.g. easein-eontaining) produets. Addition rates move between 0.05A).3%. 

Another class of thermosetting resins used as adhesives involves the polymerization of formaldehyde with urea or phenols. These materials are very cheap and find extensive use in binding wood, e.g., plywood, chipboard, and particle board. Foamed urea-formaldehyde has also been used as insulation (UFFl) in homes because of its ability to be injected into the walls of older homes. Unfortunately, the foam is not very stable and shrinks and hydrolyzes to liberate formaldehyde and possibly other toxic vapors. Recent work has, however, shown that the addition (and subsequent removal) of ammonia (NH3) to the foam can reduce the level of formaldehyde released by the polymer. This release of formaldehyde also occurs in plywood and particle board, and these materials must be sealed to avoid the formation of toxic levels (TLV = 0.10 ppm or 120 pg/m ) of formaldehyde. 

Comparatively little attention was given to the use of tannin-bonded particleboards for interior use until restrictions on formaldehyde emissions from urea-formaldehyde bonded products became a critical concern (178). Wattle tan-nin/urea-formaldehyde adhesive formulations for interior particleboards do reduce the large, short-term formaldehyde release normally observed soon after pressing, but not the slow emission that is common after extended storage (33). The scavenging effects of wattle tannins are limited to comparatively small amounts of formaldehyde because of the highly condensed nature of the tan-nin/urea-formaldehyde polymer after curing, as was also observed by Marutzky and Dix (136). 

Amino and Phenolic Resins. The largest use of formaldehyde is in the manufacture of urea—formaldehyde, phenol—formaldehyde, and melamine—formaldehyde resins, accounting for over one-half (51%) of the total demand (115). These resins find use as adhesives for binding wood products that comprise particle board, fiber board, and plywood. Plywood is the largest market for phenol—formaldehyde resins particle board is the largest for urea—formaldehyde resins. Under certain conditions, urea—formaldehyde resins may release formaldehyde that has been alleged to create health or environmental problems (see Amino RESINS AND PLASTICS). 

In 1993, worldwide consumption of phenoHc resins exceeded 3 x 10 t slightly less than half of the total volume was produced in the United States (73). The largest-volume appHcation is in plywood adhesives, an area that accounts for ca 49% of U.S. consumption (Table 11). During the early 1980s, the volume of this apphcation more than doubled as mills converted from urea—formaldehyde (UF) to phenol—formaldehyde adhesives because of the release of formaldehyde from UF products. Other wood bonding applications account for another 15% of the volume. The next largest-volume application is insulation material at 12%. 

---