| 摘要 |
Polymeric acetals of polyvinyl alcohols grafted onto polyalkylene oxide graft bases or polyurethane graft bases which contain acetal groups derived from etherified omega -hydroxy(poly)-alkoxyalkanals of the formula (I), and a process for their preparation by acetalisation of appropriate graft polyvinyl alcohols, are described. The polymeric acetals according to the invention are internally plasticised and are polymers which are generally obtainable in solid form and can be converted thermoplastically without external plasticisers to films, mouldings or coatings. Mixed acetals with other aldehydes can also be prepared and enable properties to be varied widely, including the solubility in water or in organic solvents. The polymeric acetals according to the invention can be processed or used without solvents, for example from the melt, or as organic or aqueous solutions or as aqueous dispersions. The diverse solubility spectrum, the glass transition temperatures which are significantly lowered compared with polyvinylbutyral, the thermoplastic processability without external plasticisers, the external crosslinkability, the good adhesive capacity to diverse solid materials, the corrosion-neutral behaviour toward metals and the dispersion capacity in aqueous media enable the polymeric acetals according to the invention to be used in a broad industrial area, in particular, for example, as binders in organic or aqueous solutions or dispersions or in products to be used as liquid melts, preferably in paints, coating compositions, adhesives, dispersants, pigment binders, printing inks, green ceramic sheets, sizes, fibre binders, paper, photographic printing plates, photoresist materials, and as mouldings and transparent interlayer films for composite glasses. |
