Formaldehyde for adhesion

Chem. Descrip. N-P-(Aminoelhyl)-Y-aminopropylmethyldimethoxysilane CAS 3069-29-2 EINECS/ELINCS 221-336-6 Uses Coupling agent in acrylic, epoxy, polyamide, polyether, silicone, vinyl polymers, cellulosics, furan, melamine, nitrocellulose, PU, polyvinyl butyral, and urea-formaldehyde, for adhesives, coatings, filler Ireat-menL foundry, inks, rubber, sealants, and textile applies. 

Basic feedstock for over 12 different elastomers Basic feedstock for many different rubber accelerators Very important feedstock for furnace carbon blacks Used for CR, CM, CSM, CIIR, CO, ECO, ADC, etc. Directly used for over ten different rubbers Used for production of over 14 different rubbers Used for adhesion promoters, tackifiers, curatives, PUR Needed for HR, CIIR, BUR, BIMS, AO, tackifiers, etc. Important feedstock for IR and HR rubber Feedstock for TBBS, CBS, MBS, MBTS accelerators Needed for carbon disulfide for rubber accelerators Needed for formaldehyde for adhesion, tackifiers, etc. Used for MDI and aniline for several rubber chemicals Feedstock for numerous rubber chemicals... 

For exterior appHcations, where water exposure is expected, phenol—formaldehyde (PF) or phenol—resorcinol—formaldehyde (PRF) adhesives are used. Only small quantities of this type of hardwood plywood are made, primarily for marine use. 

Polymers. AH nitro alcohols are sources of formaldehyde for cross-linking in polymers of urea, melamine, phenols, resorcinol, etc (see Amino RESINS AND PLASTICS). Nitrodiols and 2-hydroxymethyl-2-nitro-l,3-propanediol can be used as polyols to form polyester or polyurethane products (see Polyesters Urethane polymers). 2-Methyl-2-nitro-l-propanol is used in tires to promote the adhesion of mbber to tire cord (qv). Nitro alcohols are used as hardening agents in photographic processes, and 2-hydroxymethyl-2-nitro-l,3-propanediol is a cross-linking agent for starch adhesives, polyamides, urea resins, or wool, and in tanning operations (17—25). Wrinkle-resistant fabric with reduced free formaldehyde content is obtained by treatment with... 

Ammonium chloride has a number of iadustrial uses, most importantiy ia the manufacture of dry-ceU batteries, where it serves as an electrolyte. It is also used to make quarryiag explosives, as a hardener for formaldehyde-based adhesives, as a flame suppressant, and ia etching solutions ia the manufacture of ptinted circuit boards. Other appHcations iaclude use as a component of fluxes ia ziac and tin plating, and for electrolytic refining of ziac. 

Amino Resins. Amino resins (qv) include both urea- and melamine—formaldehyde condensation products. They are thermosets prepared similarly by the reaction of the amino groups in urea [57-13-6] or melamine [108-78-1] with formaldehyde to form the corresponding methylol derivatives, which are soluble in water or ethanol. To form plywood, particle board, and other wood products for adhesive or bonding purposes, a Hquid resin is mixed with some acid catalyst and sprayed on the boards or granules, then cured and cross-linked under heat and pressure. 

Resol resins thermoset on heating and are used for adhesives. Novolacs require a further source of formaldehyde in the form of hexamethylenetetramine to produce molding powders. Phenolic moldings are resistant to heat, chemicals, and moisture with good electrical and heat insulation qualities. Complex phenols from, e.g., cashew-nut shell liquid, are used in making brake... 

Linear novolac resins prepared by reacting para-alkylphenols with paraformaldehyde are of interest for adhesive tackifiers. As expected for step-growth polymerization, the molecular weights and viscosities of such oligomers prepared in one exemplary study increased as the ratio of formaldehyde to para-nonylphenol was increased from 0.32 to 1.00.21 As is usually the case, however, these reactions were not carried out to full conversion, and the measured Mn of an oligomer prepared with an equimolar phenol-to-formaldehyde ratio was 1400 g/mol. Plots of apparent shear viscosity versus shear rate of these p-nonylphenol novolac resins showed non-Newtonian rheological behavior. 

The route to crosslinked phenol-formaldehyde resins via resoles corresponds to that used by Baekeland in his original commercial technique. They now tend to be used for adhesives, binders, and laminates. The resole... 

Resorcinol formaldehyde latex (RFL) cord dips have only a limited application within the general rubber goods industry and for adhesion to be achieved with synthetic fibres it is necessary to use the systems developed by Bayer and Degussa. These systems are based upon a combination of resorcinol, a formaldehyde donor and a hydrated silica filler (commonly called the RFK system). This system is incorporated as dry ingredients into the rubber compound and is activated by the application of heat. 

Uses. Manufacture of dry cell batteries component of fluxes in zinc and tin plating fume is evolved in galvanizing operations mordant in dyeing and printing fertilizer hardener for formaldehyde-based adhesives... 

Resorcinol differs from other phenols in that it reacts readily with formaldehyde under neutral conditions at ambient temperature. To make stable adhesives, which can be cured at the point of use, they are prepared with less than a stoichiometric amount of formaldehyde. About two thirds of a mole of formaldehyde for each mole of resorcinol will give a stable resinous condensation product. The resin is formed into a liquid of convenient solids content and viscosity. Such solutions have infinite stability when stored in closed containers. Glue mixes formed at the point of use from these solutions, on addition of paraformaldehyde-containing hardeners, will have a useful life of several hours due to two principal factors (1) the paraformaldehyde depolymerizes to supply monomeric formaldehyde at a slow rate, as determined by the pH (2) the availability of the formaldehyde is also controlled by the kind and amount of alcohol in the solvent. Formaldehyde reacts with the alcohol to form a hemiacetal. This reaction is reversible and forms an equilibrium which exerts further control on the availability of the formaldehyde. 

Most furfural is produced from corncobs and oat and rice hulls, primarily by the Quaker Oats Company. The product is used in the chemical industry as a solvent and in wood rosin refining. A large amount of furfural is treated further to give furfuryl alcohol. The furfuryl alcohol is added to urea-formaldehyde resins in applications for adhesives and foundry core binders. 

The rapid growth of the pulp and paper industry following World War II coupled with a renewed scientific interest in utilization of bark and wood residues led to investigative programs on bark and wood tannins. The leather industry was continuing to decline in importance, so other alternatives were needed. One of these was replacement of phenol in whole or in part in phenol-formaldehyde adhesive formulations. This work progressed to the point where commercial quantities of polyphenolic extractives were made and sold for adhesive application. Excessive capacity and low petrochemically derived phenol prices in the 1960 s led to the demise of this effort in the United States (2,5). 

Attempts to make adhesive formulations by direct reaction of formaldehyde or its equivalent resulted in products that were excessively viscous, and the working time was too short for commercial application (57). It was concluded that formaldehyde, although readily reactive with the tannin molecule, provided much too short linkages to connect the bulky tannin molecules. This problem was circumvented by the preparation of a polymethylolphenol reagent that, when put in solution with the bark extract, formed a combination that was stable for several weeks at room temperature. When heated, the polymethylolphenol and bark extract reacted rapidly to form an infusible resin. Commercial trials were made to produce exterior-grade Douglas-fir plywood. Widespread use of the extracts for this purpose, however, was inhibited by a drop in the price of phenol below what the bark extracts could be manufactured for. (The best extract for adhesive purposes was an ammonia extract of hemlock bark converted to a sodium derivative prior to spray drying, a more costly extraction procedure than simple sodium hydroxide extraction of bark.)... 

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. 

This process cost-effectively produces high-quality glues at large quantities. The product is a low-formaldehyde resin adhesive, suitable for veneering, plywood and particle board production by the hot pressing process. The quality of the bonding complies with the requirements of DIN 68705, Part 2 respectively to DIN 68763-V20. For particle board, a perforate value according to DIN EN 120 of less 10 mg HCHO/100 g dry board will be maintained. 

Using lignin in the form obtained when it is extracted from the plant does not mean that the lignin exists in the application exactly as it did when withdrawn from the plant. It means that the lignin enters the application process as a reagent and is often reacted with other components of the product as product is produced. This is definitely the case in the largest current application for unaltered lignin, its use as a replacement for phenol in phenol-formaldehyde (methanal) adhesives. 

Methanol to formaldehyde 1890 Resins for adhesives CH3OH -b I/2O2 — HCHO -b H2O Ag wire gauze or Ag crystals... 

The 150 kilotons of ammoninm chloride that are prodnced per year are mostly nsed as fertilizer and, in order of importance, for solid electrolytes in dry cell batteries, a component of quarrying explosives, hardeners for formaldehyde-based adhesives, one component of etching solutions in the manufacture of printed circuit boards, and a component, along with zinc chloride, of fluxes in tin and zinc plating. 

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