Polyurethane finishes

AQOATHANES aqueous co-polymer fluorochemical polyurethane finishes have many value added application end uses for natural, synthetic and blended constructions. 

REZTHANE U-PF products are aqueous polyurethane finishes designed for pad application for a wide range of upgrading end uses. They all have excellent properties in resistance to degradation in washing and dry cleaning. 

On an industrial scale, the SFE-FTIR couple has been successfully used to determine aramid, polyamide and polyurethane-based fibres, which require a different finish for textile processing [127], By using CO, at 350 atm, 75°C and a flow-rate of 1.2 ml/min, the polyurethane finish [poly(dimethylsiloxane) oil] was thoroughly extracted within the first 10 min by contrast, less than 35% of sorbitol derivatives present in the aramid finish could be separated after 20 min. The separation efficiency for polyamide finish components varied between 74 and 100%, with relative standard deviations for the most extractable finishes — which were recovered by more than 98% — ranging from 5.7 to 21%. 

Dura-Wear. [Uncle Sam Chem.] Polyurethane finish. 

Mitec . C tsubishi Kasei] Isocyanate adducts for polyurethane finish for wood, plastics, automotive. 

SovermoL (Henkel KGaA] Unssqponi-fiable l dioxyl component for high-qaality polyurethane finishes. 

Lumitol . [BASF AG] Hydtoxylic poly-acrylate resins u in combination with polyisocyanates to produce polyurethane finishes with chemical and solvent resistance. 

Mitec . [Mitsubishi Kasei] Isocyanate adducts for polyurethane finishes for wood, plasdcs, automotive. 

Polyester finishes contain polyester resins, which, in turn, contain predominantly ester linkages. Polyurethane finishes need not contain polyurethane resins and the urethane linkage is not necessarily predominant in the dry paint film. However, all polyurethane finishes contain isocyanates or their reaction products, so the reader should be familiar with isocyanate reactions before proceeding further with this chapter. 

The urethane linkage is resistant to alkalis and thus urethane oils and alkyds have better alkali resistance than ordinary alkyds. This is usually accompanied by better water resistance. Urethane oils and alkyds possess a property common to all polyurethane finishes good abrasion resistance. It is claimed that they are superior to oils and alkyds for the dispersion of difficult organic pigments and carbon black, but in pigmented form they are prone to chalk and lose gloss earlier than normal alkyds and oleoresinous finishes. 

Saturated polyester-resins have been defined in Chapter 12 and their use with nitrogen resins was described in Chapter 13. The resins used in polyurethane finishes might contain a selection from the ingredients listed on p. 161 and, amongst others ... 

One or two matters common to polyurethane finishes of all types must now be covered briefly. 

In spite of the wide variety of types of polyurethane finish, certain characteristics are common to the family as a whole. These are toughness and abrasion resistance, combined with flexibility, good chemical resistance and good adhesion. 

These two-pack cold-cure solvent-borne coatings have excellent durability and abrasion resistance. They are designed for spray applications on steel, aluminium and light alloy surfaces wMch have been suitably pretreated. Base and hardener are mixed in 3 1 or 5 1 ratios as recommended by the manufacturer and the pot life is around 2 hours under normal working conditions (20 C) and should not be used after the stated time. Polyurethane/acrylic resin combination is also available. Two-pack polyurethanes are widely used in veMcle body repair and can contain isocyanate which is a basic constituent in the production of polyurethane and is the most common cause of industrial asthma and it is also a skin irritant. It should be easily identified by a label on the container which should say contains isocyanates, harmful by inhalation and in contact with skin . Waterborne two-pack polyurethane finishes are available. 

Polyurethane finish coats Very fine surface fairing and keying Not used 280-320... 

Polyurethane finish n. An exceptionally hard and wear-resistant paint or varnish made by the reaction of polyols with a multifunctional isocyanate. 

Diphenylmethane-4,4 -diisocyanate, 1% pet (polyurethane finishes 0.1% pet may lead to false-negative results)... 

Toluene-2,4-diisocyanate, 1% pet (polyurethane finishes 0.1% pet may lead to false-negative results) Dibutyl phthalate, 5% pet (plasticiser in finishes) Tricresyl phosphate, 5% pet (plasticiser in finishes) Additional dyes, 1% pet (depends on individual cases ... 

System B. inorganic Zinc/Epoxy Primer/Polyurethane Finish... 

Polyurethane. This forgiving finish is available in water-based or oil-based formulas. Oil-based polyurethane requires fewer coats than water-based polyurethane but takes longer to dry and can hold the patterns of brush marks. Water-based finish requires at least three (and up to five) coats, and even then remains susceptible to water marks. That said, water-based stain won t smell up the room with toxic fumes. Water-based finish also self-levels, so it tends not to hold brush marks. When mixing polyurethane finish in preparation for application, go with the reverse James Bond— stir, don t shake, which would introduce thousands of tiny bubbles. Work with the grain and gently brush away any lingering bubbles. Inevitably, you will leave a few, but don t worry—the marks will disappear in a month. 

Dr. Manfred Schdnfelder illustrated the effects of polyurethane finishes on the mechanical properties of the plastic. The abstract describes the propagation of a crack from the coating through to the plastic substrate. 

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