Trimethylolmelamine

LRC-100Finish. The use of LRC-100 flame retardant for 50/50 polyester cotton blends has been reported (144). It is a condensation product of tetrakis(hydroxymethyl)-phosphonium salt (THP salt) and A/A7,A7 -trimethylphosphoramide [6326-72-3] (TMPA). The precondensate is prepared by heating the THP salt and TMPA in a 2.3-to-l.0-mole ratio for one hour at 60—65°C. It is appUed in conjunction with urea and trimethylolmelamine in a pad-dry-cure oxidation wash procedure. Phosphoms contents of 3.5—4.0% are needed to enable blends to pass the FF 3-71 Test. 

Melamine—Formaldehyde Resins. The most versatile textile-finishing resins are the melamine—formaldehyde resins. They provide wash-and-wear properties to ceUulosic fabrics, and enhance the wash durabiHty of flame-retardant finishes. Butylated melamine —formaldehyde resins of the type used in surface coatings may be used in textile printing-ink formulations. A typical textile melamine resin is the dimethyl ether of trimethylolmelamine [1852-22-8] which can be prepared as follows ... 

Reaction of melamine with neutralised formaldehyde at about 80-100°C leads to the production of mixture of water-soluble methylolmelamines. These hydroxymethyl derivatives can possess up to six methylol groups per molecule and include trimethylolmelamine and hexamethylolmelamine (Figure 24.8) The methylol content of the mixture will depend on the melamine formaldehyde ratio and on the reaction conditions. 

In a typical process a jacketed still fitted with a stirrer and reflux condenser in charged with 240 parts 37% w/w (40% w/v) formalin and the pH adjusted to 8.0-8.5 using sodium carbonate solution with the aid of a pH meter. One hundred and twenty six parts of melamine (to give a melamine formaldehyde ratio of 1 3) are charged into the still and the temperature raised to 85°C. The melamine goes into solution and forms methylol derivatives. For treatment of fabrics, paper and leather this product may be diluted and cooled for immediate use. It may also be spray dried to give a more stable product. Cooling the solution would yield crystalline trimethylolmelamine, which may be air dried but which is less soluble in water than the spray-dried product. 

An MAM - vinyl chloride copolymer, with a nitrile rubber latex, optionally carboxylated, and trimethylolmelamine, bonds rayon flock to PVC sheet, and PVC to galvanised steel.(3I)... 

Since the early days of MF condensation chemistry [11], the way of synthesis has been and is still actively researched by industrial and academic groups [12]. In a typical synthesis, a conventional MF paper impregnation resin is obtained in a polycondensation reaction of melamine with formaldehyde under basic catalysis and heat. In an initial methylolation or hydroxymethylation step, mainly three different species are generated monomethylolmelamine (mnun), dimethylolmelamine (dmm) and trimethylolmelamine (tmm). 

The condensation reaction has been studied by investigating the kinetics of the initial stage of the condensation of di- and trimethylolmelamine (MF2 and MF3) in the pH range 1 to 9. Regardless of pH, the initial rate is equal to [4] ... 

Trimethylolmelamine by condensation with formaldehyde forms a synthetic, which is dried by spraying and put on the market in a micronized form. After inhalation of the merchandise (73.6 mg/1) for various periods (see Table 9) rats showed a marked dilatation of the rough endoplasmic reticulum of the serous cells in the tracheo-bronchial epithelium (Schiller 1978 Fig. 88). 

The effect of hydrogen ion concentration in the condensation of melamine (M) and formaldehyde (F) (to give trimethylolmelamine) is shown in Table IX and Preparations 3-3. 

The same procedure was used for Preparations 2 to 5 (Table X), inclusive, except that the concentration was closer to 50% than 55%, as in the foregoing case, during the trimethylolmelamine stage. Reaction in the presence of the buffer was at 50 1% in all five cases. 

In these two cases it was impractical to operate at 50% concentration throughout the reaction because the high reaction rate leads to gelation. The concentration therefore had to be lowered and the reaction time curtailed. For Preparation 6 the trimethylolmelamine solution was developed in the same way as in Preparation 1, that is, by heating 20 min at 60°C. Two hundred and eighteen grams of the 50% solution (equivalent to 0.5 mole of melamine) was diluted at once with 56.5 ml of water followed by 35.4 gm of 36% hydrochloric acid, held 2 min at 50°C, and then cooled. During reaction with the acid in Preparation 7 as well as 6 the concentration of melamine plus formaldehyde was 35%. 

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