Contact amino resins

The Food and Drug Administration (1999) permits the use of triethanolamine as a component of adhesives in food packaging as an indirect food additive, as a component of the uncoated or coated food contact surface of paper and paper board for use with dry solid foods with no free fat or oil on the surface, and to adjust pH during the manufacture of amino resins permitted for use as components of paper and paper board in the United States. 

Uses. The use of amino resins in packaging is regulated by the FDA under 21 CFR 175.105, adhesives 21 CFR 175.300, resinous polymeric coatings 21 CFR 176.170, paper and paperboard in contact with aqueous, fatty, and dry food. 

Metal cans that contain food or beverages employ a thin film of an epoxy polymer on its inside surface to control corrosion of the metal and to limit food contact with metal. Epoxy is ideally suited for this application, and the type of epoxy used is predominantly (over 98%) BPA-based. Both aluminum and steel beverage cans are typically sprayed with a water-based epoxy-acrylic system, often with an amino resin (or phenolic resin) to cross-link the lining (Oldring and Nehring, 2007). 

Usually the finished product does not cause primary sensitization, but occasionally the uncured substance does. Textile dermatitis caused by urea- and melamine-formaldehyde resins is rare. Contact allergy to amino resins is often combined with formaldehyde allergy (Fregert 1981 Belsito 1993). 

Adhesive penetration to undamaged fibers is necessary for anchoring. Pressure is needed during processing to assure good wood-to-wood contact, and also to contain the steam formed by the water that is the byproduct of condensation in the case of phenolic and amino resins. The wood-to-wood contact must be nearly intimate and the gluelines must be thinner than the diameter of a fiber for durable adhesive bonds. Because of the variety of wood shapes used in bonding, from small fibers in fiber-... 

The most common catalysts in order of decreasing reactivity are haUdes of aluminum, boron, zinc, and kon (76). Alkali metals and thek alcoholates, amines, nitriles, and tetraalkylureas have been used (77—80). The largest commercial processes use a resin—catalyst system (81). Trichlorosilane refluxes in a bed of anion-exchange resin containing tertiary amino or quaternary ammonium groups. Contact time can be used to control disproportionation to dichlorosilane, monochlorosilane, or silane. 

An amino-formaldehyde resin or acetone-formaldehyde resin has the capability to harden in alkaline media, in contact with a cement solution with a pH of 11 to 12. The presence of sintered CaO provides the required conditions for hardening of the methylol groups of the formaldehyde resin with Ca + ions and a further simultaneous reaction of the methylol groups that formed hydrate compounds, resulting in an improved dispersion and plastification of the solution. 

Coupling Of the Amino Acids For all washes, the contact time for each solvent aliquot is 2 min, unless noted otherwise, with occasional gentle stirring. Each wash aliquot is then removed completely by aspiration, leaving dry resin beads. A schematic of your peptide bound to the resin is shown in Figure 7.9. Note that your peptide is synthesized and is read from right (C-terminus) to left (N-terminus). 

An IND, BIA, or NDA submission should list the source and country of origin for every animal- and human-derived raw material [3, 46]. Lot numbers and supplier information should be available on site during an inspection (21 CFR 211.184). It is also recommended to contact vendors to determine if less-obvious raw materials such as amino acids used in the basal tissue culture medium, enzymes used to make protein hydrolysates, cholesterol, and some detergents (e.g., polysor-bates) are animal-derived. In some cases, protein A (isolated to make chromatography resins) has been purified over human IgG immunoaffinity columns, and the use of these resins should also be tracked and reported (21 CFR 211.184) [46]. 

---