Methylated melamines

N,]S7-bis(methoxymethyl)uron was first isolated and described in 1936 (41), but was commercialized only in 1960. It is manufactured (42) by the reaction of 4 mol of formaldehyde with 1 mol of urea at 60°C under highly alkaline conditions to form tetramethylolurea [2787-01-1]. After concentration under reduced pressure to remove water, excess methanol is charged and the reaction continued under acidic conditions at ambient temperatures to close the ring and methylate the hydroxymethyl groups. After filtration to remove the precipitated salts, the methanolic solution is concentrated to recover excess methanol. The product (75—85% pure) is then mixed with a methylated melamine—formaldehyde resin to reduce fabric strength losses in the presence of chlorine, and diluted with water to 50—75% soHds. Uron resins do not find significant use today due to the greater amounts of formaldehyde released from fabric treated with these resins. 

The crosslinkers examined in this study were aminoplast resins 1-4 selected from melamine-formaldehyde, urea-formaldehyde, benzoguanamine-formaldehyde, and glycoluril-formaldehyde resins, all of which undergo the crosslinking sequence shown in Scheme 1. The response of these crosslinkers to acid catalysis in thin films is compared on a relative basis to the well studied methylated melamine, 1 19-11). 

Acid Concentration Required for Crosslinking Resist Films. The strong acid catalyzed reaction of methylated melamine 1 with novolak in a film was studied first in order to estimate the amount of acid generated in experimental AHR resists upon exposure. Incremental amounts of a 1% solution of p-toluenesulfonic acid (pTSA) were added to a resist solution which contained no RSAG. The solutions were coated onto wafers and subjected to a typical bake cycle. The dissolution rate... 

Ingredients methylated melamine-formaldehyde resin. 72 wt% isobutyl alcohol, 18 wt% formaldehyde, < 0.9 wt% glycidoxypropyltrimethoxysilane. I0wt%. 

Determination of MCT. The coating systan used consists of a thermosetting acrylic latex, Hycar 2600X256 (EFGoodrich Chenical Division) containing 15 wt.% of a partially methylated melamine formaldehyde, Cymel 373 (American Cyanamid Corporation). Adjustment of the pH level of the coating was achieved by the addition of p—toluene sulfonic acid. 

Methylated melamine, modified Methylated melamine formaldehyde RESIN GFL Sybron... 

Materials from starch crosslinked with melamine-formaldehyde, methylated melamine-formaldehyde, and other amine-aldehyde resins were patented as binders for filter paper,1336 milk filter sheet materials,1338 and aqueous papercoating compositions containing clay, titanium(IV) oxide, butadiene-styrene latex, and calcium octadecanoate.1396,1397 Foams for filters were developed.1398 A heatsetting adhesive was one of the first applications reported for starch crosslinked by urea-formaldehyde and phenol-formaldehyde resins.1331,1340-1342,1347,1372,1399... 

A highly methylated melamine-formaldehyde textile treating resin may be made as follows (19) A methanol solution of formaldehyde (55% formaldehyde/35% methanol/10% water) is charged to a reaction kettle and adjusted to a pH of 9.0-9.5 with sodium hydroxide. Melamine is then added to give a ratio of 1 mole of melamine for each 6.5 mol of formaldehyde. The mixture is heated to reflux and held for 0,5 h. The reaction mixture is then cooled to 35 C and more methanol is added to bring the ratio of methanol to melamine up to 11 mol to 1 mol. With the batch at 35 C, enough sulfuric acid is added to reduce the pH to 1.0. After the reaction mixture is held at this temperature and pH for 1 h, the batch is neutralized with 50% sodium hydroxide and the excess methanol stripped off to... 

Amino resins should be stored at 20-27""C. Lower temperatures can cause crystallization of hexakis(methoxymethyl)melamine and partially methylated melamine resins. Careful reheating is then required. Maximum storage temperature for fully... 

Amino resins are also employed in waterborne systems used in industrial coatings (e.g., automotive spray primers and basecoats, can and coil coatings). Stable coatings can be formulated with hexakis(methoxymethyl)melamine or partially methylated melamine resins. 

Nielen, M. W. F. and van de Ven, H. J. F. M. Characterization of (methoxy-methyl)melamine resins by combined chromatographic/mass spectrometric techniques. Rapid Commun. Mass Spectrom., 10, 74,1996. 

Chem. Descrip. Partially methylated melamine-formaldehyde resin in IP/V butanol... 

Chem. Descrip. Methylated melamine-formaldehyde resin (75%) in isobutanol... 

Uses Methylated melamine-formaldehyde in combination with alkyd, acrylic, epoxy, and oil-free polyester resins for water-borne and solv.-based baking enamels Features Unplasticized... 

Chem. Descrip. Partially methylated melamine resin in isobutanol Uses Crosslinking agent for thermoset coatings Features Fast, low temp, cure, high crosslink efficiency Properties APHA30 max. color dens. 9.4-9.6 Ib/gal vise. (Gardner-Holdt) Z,.Z, flash pt. (PMCC) 31 C 80-84% solids Resimene 730 [Solutia]... 

Chem. Descrip. Modified high solids methylated melamine contg. 20% styrene allyl alcohol in ethanol... 

---