Low hydroxyl value vegetable oil-based polyol and preparation method thereof

Abstract

The invention discloses a low hydroxyl value vegetable oil-based polyol and a preparation method thereof. The preparation method comprises: (1) mixing mixed vegetable oil, a carboxylic acid, an inorganic acid catalyst, a hydroxylation reagent and deionized water according to a certain ratio, heating to a temperature of 35-45 DEG C, adding hydrogen peroxide in a dropwise manner under vigorous stirring, controlling the adding speed to maintain the reaction temperature at 40-65 DEG C, maintaining the reaction temperature for 5-7 h after completing the adding, carrying out standing layering after completing the reaction to separate a water phase, neutralizing, carrying out water washing, and carrying out pressure reducing distillation to obtain the mixture of a tung oil polyol and epoxy vegetable oil; and (2) mixing the mixture obtained in the step (1) and an alkali catalyst according to a certain ratio, heating to a temperature of 90-140 DEG C under the protection of nitrogen, carrying out a reaction for 2-6 h, carrying out acid neutralization after completing the reaction, carrying out water washing, and carrying out pressure reducing distillation to obtain the low hydroxyl value vegetable oil-based polyol product. According to the present invention, the hydroxyl value of the prepared low hydroxyl value vegetable oil-based polyol product is 50-110 mgKOH / g, the acid value of the prepared low hydroxyl value vegetable oil-based polyol product is less than 1.0 mgKOH / g, the water content of the prepared low hydroxyl value vegetable oil-based polyol product is less than 0.1 wt%, the yield is more than 90%, and the prepared low hydroxyl value vegetable oil-based polyol product can be used for preparing polyurethane soft foam materials, polyurethane elastomers, and the like.

Description

technical field [0001] The invention belongs to the field of polyurethane materials, and in particular relates to a low hydroxyl value vegetable oil-based polyol and a preparation method thereof. Background technique [0002] Polyurethane materials have been widely used in industry and people's daily life due to their good mechanical properties and easy molding. The main raw materials used to produce polyurethane include isocyanates, polyols and other additives, of which polyols account for more than 50%. In the process of industrial production, polyols are mainly used in the field of polyurethane, so the factors affecting the polyurethane industry are also the main factors affecting the polyol market. Polyols can be divided into polyether polyols and polyester polyols according to their molecular structure. Among them, polyether polyols dominate the market, accounting for more than 70% of the entire polyol demand. [0003] Typically, polyols are prepared from petroleum. ...

AI Technical Summary

Problems solved by technology

However, tung oil is used to prepare high-quality vegetable oil polyols. Because tung oil has a high degree of unsaturation and is the only unsaturated vegetable oil with conjugated double bonds in nature, the iodine value reaches more than 170, and more than 85% of the unsaturated bonds are Carbon-carbon conjugated triene bonds, so the presence of conjugated double bonds in tung oil in the process of preparing polyol epoxidation makes the epoxy group highly reactive, poor in selectivity, and prone to side reactions, thereby generating macromolecular cross-links. Co-product, resulting in a sharp increase in viscosity, usually solid at room temperature, cannot be used for further synthesis of polyurethane materials

Research literature (e.g. Epoxidation of Natural Triglycerides with Ethylmethyldioxirane, Journal of the American Oil Chemists' Society, 1996, 73:461-464) examines different vegetable oils such as corn oil, soybean oil, sunflower oil, cottonseed oil, tung oil During the epoxidation process of unsaturated vegetable oils, it was also found that the tung oil with only conjugated double bonds undergoes a crosslinking reaction during the epoxidation process, resulting in a sharp increase in viscosity and cannot be used to prepare polyurethane materials.

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