Amino resins, hardening

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... 

Cross-linking with aminoplasts and phenoplasts constitutes an important class of hardeners for high molecular-weight epoxy resins that require elevated temperature cures (see Amino resins). 

Amino and functional aromatic phosphates, phosphonates, and phosphine oxides have also been used as reactive components to impart flame retardancy to cured epoxy resins. Phosphine oxides are particularly hydrolytically stable and several studies have been reported, for example, of the curing of epoxy resins with bis(aminophenyl) alkyl and aryl phosphine oxides65-67 (Structure 5.19). The relative performances of epoxies cured with aromatic diamine hardeners containing phosphine oxide, phosphinate, phosphonate, or phosphate units have recently been assessed.68 Aromatic phosphine oxides have been functionalized also with maleimide and hydroxyl groups for use as epoxy resin hardeners.69,70... 

Heat heatment can also reduce the pH of the wood to a value of 3.5 [10], which might retard or accelerate the curing of adhesives, depending on the type of adhesive used for bonding. For instance, the acetic and formic acids which are present in wood after heat treatment might neutralize the alkaUne hardeners used for phenolic resins and hinder the adhesive hardening. On the other hand, a low pH of the wood surface could accelerate the chemical reactions of the acid catalyzed amino resins [31]. 

Methyl methacrylate-2-ethylhexyl acrylate-MA terpolymers, in the compositional range 40-50 42-52 8, have been prepared in naptha at 130-140 C to obtain coating resins/ Postreaction of the materials with trimethylol-propane, which introduced both hydroxyl and carboxyl sites on the terpolymer backbone, provided reactive moieties for amino-resin crosslinkers. Unsaturated monohydroxy dialkyl maleates and fumarates, such as 2-hydroxyethyl isobutyl fumarate, have also been copolymerized with various acrylate-methacrylate combinations to obtain low-viscosity, heat-hardening, filmforming copolymers.These copolymers may also be crosslinked with amino resins to provide valuable protective coating. 

Hardeners and Vulcanizing Ag ents. For epoxy resins, acyUiydrazide derivatives of amino acids are used (245). 

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. 

Hardeners - [AMINO AC IDS - SURVEY] (Vol 2) -borate esters as pORONCOMPOUNDS - BORIC ACID ESTERS] (Vol 4) -m cosmetics [COSMETICS] (Vol 7) -for epoxy resins pPOXY RESINS] (Vol 9) -thioglycolic acids as [IHIOGLYCOLIC ACID] (Vol 24)... 

We investigated the use of the molding resin powder (<150 m) as a filler for construction materials composed of bisphenol A type epoxy resin and amine type hardener, and compared the material properties with those produced with a silica powder filler (<150 fi m). Furthermore, the effect of surface treatment of the molding resin powder on these properties was examined by using epoxy or amino silane coupling agents, which were added at lwt% to the molding resin powder and heated at 100°C for 1 hr. 

Uses Catalyst, hardener for acid-curing one-pack wood coatings, plasticized urea resins, amino-al blends Features Long storage stability... 

Reactive liquid polymers (RLPs) The Uquid rubbers most often used in epoxy adhesives are those based on acrylonitrile-butadiene copolymers or on long-chain polyethers. To act as effective tougheners, however, they cannot be directly added to the formulation but have to be prereacted with some of the epoxy resin, or sometimes with the amino hardeners in two component paste adhesives (adduct fonnatiou). To achieve this, only RLPs with reactive eud groups are used by the formulator. 

For a general introduction, see Wood adhesives - basics. Aminoplastic resins are polycondensation products of the reaction of aldehydes with compounds carrying amine or amide groups. Formaldehyde is by far the primary aldehyde used. The name amino-plastic is traditional, but is a misnomer these are thermosetting, irreversibly hardening resins. Two main classes of these resins exist urea-formaldehyde (UF) resins and melamine-formaldehyde (MF) resins. Today, for wood adhesives, pure MF resins are not used anymore because of cost, and only melamine-urea-formaldehyde (MUF) adhesives are used. The main use of these resins is in composite products such as particle board, plywood, medium density fibreboard (MDF), oriented strand board (OSB), glu-lam/flngerjointing and furniture. 

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