Impregnation agents

A number of higher poly(vinyl ether)s, in particular the ethyl and butyl polymers, have found use as adhesives. When antioxidants are incorporated, pressure-sensitive adhesive tapes from poly(vinyl ethyl ether) are said to have twice the shelf life of similar tapes from natural rubber. Copolymers of vinyl isobutyl ether with methyl acrylate and ethyl acrylate (Acronal series) and with vinyl chloride have been commercially marketed. The first two products have been used as adhesives and impregnating agents for textile, paper and leather whilst the latter (Vinoflex MP 400) has found use in surface coatings. 

Cured phenolics are universally brittle in nature. This is true of both resoles and novolacs and does not depend much on the source of methylene used to promote cure. Consequently, the fillers used in molded articles are highly important to the design of the manufactured product. With resoles, the fiber or filler are usually the primary component of the final composite, with the resole acting as a binder or impregnating agent. With novolacs the resin may be the major component in the molded part. Poly-silanes and other organic polymers are also added in some applications to promote impact resistance and toughness [192]. 

Imprkgnier-lack, m. impregnation lacquer, -mittel, n. impregnating agent. -SI, n. impregnating oil. 

Other agents used to impregnate keiselguhr include formamide and propan-1,2-diol. In the case of these impregnating agents, the mobile phases used to develop the treated plates have to be of low polarity to avoid washing the agent off the plate. 

Ethylsilicate-32 is widely used in various spheres of economy, e.g. as a cementing and impregnating agent in the production of molds for precision molding, etc. For example, the cement obtained by mixing ethylsilicate with various fillers (quartz flour, cinder) solidifies in the cold. It is resistant to acids and weak alkali. Water only improves its mechanical properties. After baking at 300°C, the cement becomes resistant to concentrated alkali as well. 

Ethylsilicate-32 can be used as an impregnating agent to reduce porosity and to waterproof various materials (brick, graphite, asbestos, leather, tex-... 

Mayer, H. (1994) Silicone microemulsions as aqueous primers and impregnating agents for wall coatings. (Part 1). Surf. Coatings Int., 77, 162-8. 

Materials and Methods of Application. All paper substrates for the impregnating agent/paper system studies were a buffered wood sulfite, Gracie Sons Acid-Free Lining Paper, Lot 3 (supplied by Charles R. Gracie Sons, Inc., New York, N.Y. 10022). Samples were all cut in... 

Table II. Double Folds to Rupture0 for Artificially Aged (100°C, < 10% r.h.) Papers Treated with Impregnating Agents...

PERSISTOL SIN is a sillcone-type impregnating agent for the water-repellent finishing of fabrics of all types. According to the type of substrate, it is necessary to use CONDENSOL I New or CONDENSOL II. 

Kovacs-Hadady 136] published the. separation of barbiturates using silica gel impregnated with several various solutions. Table 10.24 shows the R values of various barbiturate pairs using various impregnation agents indicating their separation. 

Solvent-free and solvent-based silane impregnating agents are commercially available. As a precautionary measure, application of silane-based impregnating agents should be avoided in direct sunlight, strong winds or in rain. To maximise the chances of success it is necessary to use a very high concentration of silane, up to 100% (Stockdale, 1991). 

High-quality impregnating agents must fulfil four conditions ... 

Application methods for the impregnating agent The durability of the water-repellent effect depends not only on the product quality but also on the depth of penetration achieved. In order to ensure sufficient penetration, the impregnating solution should be applied by spraying or flooding. Airless spraying techniques can also be used provided the seals and hoses are solvent-resistant. 

Use as impregnating agents or additivation thereof (inorganic and porous surfaces, building materials, anti-grafliti)... 

Basically, stone samples impregnated under optimum conditions in the laboratory usually have a better distribution and higher penetration depth of impregnating agent than identical stone materials on actual fafades [55, 27]. The dilution series was discussed in Sample preparation and analytical methods . 

---