Hintyağı ve keten yağı temelli bağlayıcıların film özelliklerinin geliştirilmesi

Abstract

Yüzey kaplama endüstrisinde, yağ ile modifiye edilmiş alkid reçineleri ve üretan yağlan büyük miktarlarda üretilmektedir. Yağ ile modifiye edilmiş alkid reçineleri, trigliserid yağlardan elde edilen kısmi gliseridlerin organik poliasitlerle reaksiyonundan, üretan yağlan ise kısmi gliseridlerin diizosyanatlarla reaksiyonundan elde edilirler. Yüzey kaplayıcılann üretimlerinde kullanılan yağ, polialkol, poliasit ve izosyanat komponentierinin cinsi ve oranlan değiştirilerek veya örneğin yanmazhk özelliğinin kazandınlması için halojenli veya imidli maddeler gibi maddeler ilave edilerek film özellikleri geliştirilebilir. Bu çalışmada film özellikleri geliştirilmiş ürünler elde etmek amacıyla alkol komponenti hinryağı, yağ komponenti keten yağı olmak üzere elde edilen ara üründen alkid reçinesi ve üretan yağı elde edilmiştir. Aynca klasik yöntemle elde edilen alkid reçinesi ve üretan yağı orto - benzoik asit ftalimidi ile modifiye edilerek ürünlerin yanmazlık özelliği incelenmiştir. Elde edilen ürünlerin film özellikleri incelenerek organik yüzey kaplayıcı olarak değerlendirilebilecekleri anlaşılmıştır.

Surface coatings represent a large segment of the chemical industry. The term organic coatings encompasses conventional paints, varnishes, enamels, lacquers, water-emulsion and solution finishes, nonaqueous dispersions (organosols), plastisols, and powder coatings. However, the term paint is often used nonspecifically to cover all of these categories as though it were synonymous with coatings. The binders of conventional paints are, for the most part, raw or processed unsaturated vegetable oils, e.g., linseed, dehydrated castor, soya, etc., often modified with natural or low molecular weight synthetic resins. Among the other materials, alkyd resins and polyurethanes are finding increasing use in the coatings industry. Alkyd resins are oil-modified polyester resins produced by the condensation reaction of polyhydric alcohols, polybasic acids, and monobasic fatty acids. The polyfunctional components build the polymer structure, whereas the monobasic acid controls the polymerization. The most widely used polyol is glycerol, and the most commonly used polybasic acid is phthalic acid. Other polyols include pentaeritritol, trimethylol propane, and sorbitol. Aliphatic dibasic acids such as adipic and sebacic give softer polymers than phthalic anhydride. A functionality of at least two is required in both the polyol and polyacid to achieve a significant degree of polymerization. A functionality of three or more in either reactant leads to gelation. Thus, if ethylene glycol reacts with phthalic anhydride, a linear polymer forms and no gelation occurs. However, when glycerol reacts with phthalic anhydride, a network of cross links forms which eventually insolubilizes the polymer. Alkyd resins are used in almost every phase of industrial and architectural finishing. They are extensively used in paints and coatings. Some advantages include good gloss retention and fast drying characteristcis. However, most unmodified alkyds have low chemical and alkali resistance. Alkyds can be modified with drying, semidrying, and nondrying oils; the oil or the oil acids may be used. The type of oil selected depends on the color and drying characteristics required of the final coating.