Yellowing formaldehyde resin

Korai (2001) also considered the importance of density profile of composites made from acetylated fibres in determining mechanical properties. Fibres of yellow cedar were acetylated with vapour-phase acetic anhydride and fibreboards were made from these, bonded with melamine formaldehyde resin. The results from this study indicated that bonding between fibres was the most important property determining mechanical properties. 

Phenol/carbohydrate/urea/formaldehyde resin with molar ratios of 1 1 0.125 2, 2.09 Pa-s viscosity, bonded between two parallel-laminated yellow birch veneers for 5 minutes. 

Phenol-formaldehyde resin Yellow, smoky Phenol, formaldehyde Very difficult to ignite, vapor reaction neutral... 

Heucorox Yellow 145 MF, Heucorox Yellow 150 MF. See Iron oxide yellow monohydrate Heveagrip. See Resorcinol-formaldehyde resin Heveasyn PVC Latex. See Polyvinyl chloride Heveatex Acrylic. See Acrylic resin Heveatex Nitrile. See Butadiene/acrylonitrile copolymer... 

Resorcinolphthalein. See Fluorescein Resorcinol phthalein sodium. See D C Yellow No. 8 Fluorescein sodium Resorcinol resin. See Resorcinol-formaldehyde resin... 

Antimony trioxide Barium carbonate Barium nitrate Bismuth oxide Cerium oxide Cobalt Copper nitrate (ic) Coumarone/indene resin Feldspar Lead oxide, yellow Molybdenum trioxide 2-Octanol Potassium carbonate Sulfur Zirconium silicate enamels, automotive Urea-formaldehyde resin enamels, baking Gilsonite... 

Nitrocellulose, polyester, acrylic and methacrylic ester copolymer, formaldehyde resin, rosin, cellulose acetate butyrate are the most frequently used polymers in nail polish formulations. Solvents were selected to suit the polymer used. These include acetone, methyl acetate, ethyl acetate, butyl acetate, methyl glycol acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, isopropyl alcohol, methyl chloroform, and naphtha. Solvents constitute a substantial Ifaction of the composition usually around 70%. Reformulation is ongoing to improve the flexibility and durability of the nail polish. Other efforts are directed to improve antifungal properties,to eliminate ketones and formaldehyde resin (ketones because of their toxicity and irritating smell and formaldehyde resins because they contribute to dermatitis), and elimination of yellowing. All efforts are di-... 

An MF resin, Kauramin CE 5549, was proposed as a consolidant for waterlogged wood and lacquerwork (Hoffmann and Wittkopper, 1999) as a replacement for Arigal C and Lyofix DML (Haas, 1969 Grattan and Clarke, 1987). The pre-polymer is applied as a solution in water. It was cured in solution using an added catalyst and heat. Butylated amino-formaldehyde resins were used as coatings, especially for ceramics (Chinaglaze) (Tennent, 1983). The resin solution is mixed with an acid catalyst before apphcation. Chinaglaze was a UF resin modified by the addition of an alkyd (phthalic acid polyester), which yellows badly. 

Urea-formaldehyde resins exhibit only little resistance to weathering. They yellow very quickly and develop surface cracks. At the same time, they change their mechanical properties very rapidly [32]. 

To produce a moulding composition, aniline is first treated with hydrochloric acid to produce water-soluble aniline hydrochloride. The aniline hydrochloride solution is then run into a large wooden vat and formaldehyde solution is run in at a slow but uniform rate, the whole mix being subject to continuous agitation. Reaction occurs immediately to give a deep orange-red product. The resin is still a water-soluble material and so it is fed into a 10% caustic soda solution to react with the hydrochloride, thus releasing the resin as a creamy yellow slurry. The slurry is washed with a counter-current of fresh water, dried and ball-milled. 

The resins used to make fluorescent pigments are usually toluenesulphonamide-melamine-formaldehyde matrices. The dyes used for this purpose include Cl Disperse Yellow 11, Rhodamine 6G (Cl Basic Red 1) and Rhodamine B (Cl Basic Violet 10). More details of the fluorescent dyes used have been given in a review by Christie [31]. 

Southern pine, Douglas-fir, and yellow poplar stakes were impregnated with phenolic resin and cured (impreg) or impregnated with phenolic resin, compressed, and cured (compreg). Separate samples were treated with urea-formaldehyde and cured. These samples were placed in the ground and their average lifetime determined. The results are shown in Table I (18). 

The Polymerization of Aldehyde is readily effected. When aldehyde is warmed with a strong solution of an alkali, the solution becomes yellow in color and a resin-like substance precipitates. This is called aldehyde-resin. Its chemical composition is not known. It is probably formed as the result of polymerization and dehydration of aldehyde. It will be remembered that formaldehyde is not converted into a resin in this way. The reaction is, however, characteristic of other aldehydes. 

Bright yellow Ammonia, amines, formaldehyde Amino resins... 

Because of the tertiary nitrogen, these reactant resins cannot form chloroamines and therefore cannot evolve any hydrogen chloride. In addition, 4,5-dihydroxy-1,3-dimethylol ethylene urea is tetrafunctional, since the CHOH groups in the 4 and 5 positions also possess methylol characteristics. Cotton treated with triazone is more stable to acids and alkalis than DMEU products, but it has to be rinsed well because of its fishy odor. In addition, it tends to become yellow at high temperatures. AT,N -Di-methylol-N,iV -dialkyl urea, on the other hand, cannot be employed as a reactant resin since its equilibrium tends considerably toward the formaldehyde side ... 

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