Adhesion titanates

Adhesion promoting silanes are often added to improve adhesion to various substrates. As is the case with urethane sealants, silanes with a dual-reactive nature are typically used. Examples of such silanes are mercapto- and epoxy-functional silanes. Organic titanates may also be used. 

Products similar to (4) are obtained if one starts with TiCl instead of a tetraaLkyl titanate (75). These products are useful as adhesives (qv), as textile-treating agents to impart water repeUency, and as coatings and sizes for treating paper. 

Addition of one mole of P,P -dipheny1methy1enediphosphinic acid to tetraisopropyl titanate gives a chelated product, the solutions of which can be used as a primer coat for metals to enhance the adhesion of topcoats, eg, alkyds, polyalkyl acylates, and other polymeric surface coating products, and improve the corrosion resistance of the metal to salt water (102). 

Organic titanates perform three important functions for a variety of iadustrial appHcations. These are (/) catalysis, especially polyesterification and olefin polymerization (2) polymer cross-linking to enhance performance properties and (J) Surface modification for adhesion, lubricity, or pigment dispersion. 

Sufficient titanate leads to a fully hardened polymer. Using only enough titanate to react with free hydroxyls, the resin may subsequently be cured at lower cost with conventional cross-linking agents. The titanated epoxy resin has a low power factor, which is important in electrical appHcations, eg, potting components and insulation (see Embedding). Titanates improve adhesion of metals to epoxies. 

The chelated organic titanates also function as adhesion promoters of the ink binder to printed substrates such as plastic films, paper, and aluminum foil (504). The acetylacetone complexes of titanium are the preferred products for promoting adhesion of printing inks to polypropylene films. 

Mixtures of a titanium complex of saturated diols, such as TYZOR OGT, and a titanium acylate, such as bis- -butyl-bis-caproic acid titanate, do not have a yellowing or discoloring effect on white inks used to print polyolefin surfaces (506). The complexes formed by the reaction of one or two moles of diethyl citrate with TYZOR TPT have an insignificant color on their own and do not generate color with phenol-based antioxidants (507). The complexes formed by the addition of a mixture of mono- and dialkyl phosphate esters to TYZOR TBT are also low color-generating, adhesion-promoting additives for use in printing polyolefin films (508). 

Other Inks. The alkan olamine titanates, such as TYZOR TE, when mixed with a coloring agent used to print fibrous materials such as cotton, wool, or silk, promote adhesion of the dye molecule to the fiber, thus minimizing bleeding of the printed design (511). 

Adhesion promotion Chromium complexes, silanes, titanates, zirconium aluminates Al, Cr, Si, Ti, Zr... 

In principle, all lamellar minerals may be used as barrier pigments, e.g., micaceous iron oxide [5.167]-[5.169], layer silicates (mica), linear polymeric silicates (wollas-tonite), and talc [5.170], However, untreated mica and talc are not very suitable because they are highly permeable to water [5.57]. The surface can be modified with, for example, silanes or titanates, to reduce water permeability and improve adhesion... 

Wetting agents Adhesion promoters Optical property modifiers Pigments Ionic and nonionic surfactants Silanes, titanates, block and graft copolymers Inorganic Ti, Fe, and Cr oxides, Cd, Ba, and Pb sulfides, sulfates, and chromates... 

Titanates have been instrumental in the bonding of fluorinated resins to packaging films, poly(hydantoin)—polyester to polyester wire enamel, polysulfide sealant to polyurethane (a phosphated titanate is recommended), polyethylene to cellophane using a titanated polyethylenimine, and silicone mbber sealant to metal or plastic support using polysilane (Si—H) plus polysiloxane (Si—OR) and titanate as the adhesive ingredients (450—454). Polyester film coated first with a titanium alkoxide, then with a poly(vinyl alcohol)—polyethylenimine blend, becomes impermeable to gases (455). 

Organic titanates and zirconates have been found to provide several important functions as additives for organic adhesives and sealants. At least eight primary functions have been proposed.18 Organic titanates and zirconates can be used as... 

Monoalkoxy titanate Chelate titanate Quat titanate Neoalkoxy titanate Cycloheteroatom titanate Stearic acid functionality aids in dispersion of mineral fillers in polyolefins Greater stability in wet environments Water-soluble, aids adhesion of water-soluble coatings and adhesives Eliminates pretreatment associated with fillers, can be used as a concentrated solid additive Ultrahigh thermal properties for specialty applications... 

Technical Note, Adhesives and Sealants, DuPont Tyzor Organic Titanates, Wilmington, DE, 2001. 

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