Oils and Alkyds

Mineral spirits, a type of petroleum distillate popular for use in solvent-based house paints, consist mainly of aUphatic hydrocarbons with a trace of aromatics. This type of solvent finds use in oil- and alkyd-based house paints because of its good solvency with typical house paint binders and its relatively slow evaporation rate which imparts good bmshabiUty, open-time, and leveling. Other properties include lower odor, relatively lower cost, as well as safety and health hazard characteristics comparable to most other organic solvents. 

Titanates react with ester groups ki paint vehicles, eg, linseed oil, tuna oil, and alkyds, and with hydroxy groups, eg, ki caster oil and some alkyds, to prevent wrinkling of paint films (104,447). 

Pentaerythritol with its four primary hydroxyl groups is used for the preparation of tetraesters and presents Httie difficulty except for its high melting point of 263°C, when pure. Pentaerythritol tetraesters are used in aircraft lubes, synthetic drying oils, and alkyds. Esters derived from trimethylo1 alkanes and dipentaerythritol are also used in alkyd resins (qv). Esterification may take place in situ during preparation of the alkyd. 

Urethane alkyds and urethane oils are oil and alkyd resin-modified polyurethanes dissolved in a volatile solvent. Upon application and solvent evaporation, the coating is crosslinked and cured via oxidation by atmospheric oxygen. 

The cementitious substrates include concrete, masonry, sand-cement, and gypsum plasters. All these substrates retain moisture and are alkaline in nature. The surface alkalinity can result in a chemical attack or saponification of certain types of binders used in paints, notably oils and alkyds, resulting in a marked diminution in the paints resistance to washing, abrasion, and weathering. Alkyd paints are, therefore, not used on fresh concrete, masonry, and plaster surfaces. 

Paints, waterproof Paints oil and alkyd vehicle, and water thinned... 

Modified phenolic resins are condensation products of the resol type which contain other starting materials besides phenol and formaldehyde (e.g., acrylic monomers). The phenolic component itself is often modified (alkyl- or arylphenols). Modification with rosin is the most important one. The compatibility of phenolic resins with other binders can be substantially improved by modification. Rosin-modified phenolic resins may be combined with linseed oils and alkyd resins. Examples of use include putties, priming coats, rust protection paints, and colored topcoats. 

The solvency of cycloaliphatic hydrocarbons is between that of aliphatic and aromatic hydrocarbons. They have a high solvency for fats, oils, oil-modified alkyd resins, styrene-modified oils and alkyd resins, bitumen, rubber, and other polymers. Polar resins (e.g., urea-, melamine-, and phenol-formaldehyde resins), as well as alcohol-soluble synthetic resins and cellulose esters are, however, insoluble. 

Compared to aliphatic hydrocarbons, aromatic hydrocarbons (DIN 51633) have a higher solvency for oils, castor oil, oil-modified alkyd resins, styrene-modfied oils and alkyd resins, saturated polyester resins, polystyrene, poly(vinyl ethers), polyacrylate and polymethacrylate esters. poly(vinyl acetate), vinyl chloride and vinyl acetate copolymers, and many low-polarity resins. 

Uses Formaldehyde for water-sol. or water-disp. polymers, baking enamels, clear paper coatings, short oil and alkyd varnishes... 

Uses Maleic resin for general purpose oil- and alkyd-based paints Properiies Gardner 8 max. color m.p. 95-110 C acid no. 20-25 Worl inGM203 [Woriee-Chemie]... 

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. 

The main outlets for urethane oils and alkyds are in varnishes for floors, boats and general use in undercoats and in industrial maintenance finishes (where gloss retention is less important than long-lasting film integrity and resistance to water and chemicals). 

Except for urethane oil and alkyd finishes, all polyurethanes require solvents that will not react with isocyanates alcohols and ether-alcohols are obviously out. The water content of the solvents should be negligible. Manufacturers often label their solvents urethane grade , implying low water content. Solvents readily miscible with water, e.g. acetone, should be treated with suspicion, as they can take up water from the atmosphere. Obviously the exact choice of solvent will vary considerably with the finish composition. 

The usual thickeners and flow agents can be used. The usual driers and antioxidants are used in urethane oils and alkyds. Catalysts which speed up the curing reaction (and reduce pot-life) are tertiary amines and metal salts, particularly tin salts. The latter should be checked for toxicity before inclusion in paint. 

Finishes based on urethane oils and alkyds and blocked isocyanates do not present the same hazards. 

Sorbitol s6r-b9- t61 [sorb fruit of the service or related trees + -itol] (1895) n. CeHg (0H)6. Polyhydric alcohol which has attracted some interest as a component of synthetic drying oils and alkyd-type resins and surfactants. Sp gr, 1.47 mp, 97.5°C. 

The polymer is amorphous and soluble. In this polymer, however, the side groups are rigid and they restrict considerably the bending and coiling of the polymer chains. Except at high molecular weights (unsuitable for paints), polystyrene is therefore weak and brittle, and styrene copolymers (sometimes styrene is copolymerized with drying oils and alkyds) are more suitable as paint resins. 

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