Composition and proportions of antifreeze liquid
Content
What does the anti-freeze consist of?
Alcohols
To prevent freezing of glass in winter, it is necessary to lower the crystallization temperature of water. The simplest aliphatic alcohols are rational substances for solving this problem. 3 types of monohydric alcohols are used, both in a mixture and in mono:
- ethanol
Not poisonous; crystallizes at -114 °C. It was used until 2006, however, due to the high cost and frequent cases of oral use in the form of surrogates, it was excluded from the composition.
- Isopropanol
Unlike ethanol, isopropyl alcohol is cheaper, but has a toxic effect and the smell of acetone.
- methanol
Differs in the best physical and chemical indicators. However, it is highly toxic and banned from use in a number of countries.
The content of technical alcohols in antifreeze varies from 25 to 75%. As the concentration increases, the freezing point of the mixture decreases. Thus, the composition of anti-freeze up to -30 ° C frost includes at least 50% isopropyl alcohol.
Detergents
The next function of antifreeze fluid is the removal of dirt and streaks. Anionic surfactants are used as detergent components, which act regardless of temperature. Also, surfactants improve the mixing of sparingly soluble components and alcohols with water. Percentage - up to 1%.
Denaturation
To combat the ingestion of washer fluids, special additives with an unpleasant odor are introduced. More often, pyridine, phthalic acid esters, or ordinary kerosene are added. Such compounds have a repulsive odor and are poorly separated in alcohol mixtures. The share of denaturing additives is 0,1–0,5%.
Stabilizers
In order to maintain performance properties, toxic ethylene glycol or harmless propylene glycol is added to the anti-freeze. Such compounds increase the solubility of organic components, extend the period of use, and also maintain the fluidity of the liquid. The content is less than 5%.
Flavours
To eliminate the “acetone” aroma, isopropanol-based glass cleaners use fragrances - aromatic substances with a pleasant smell. The component share is about 0,5%.
Food colors
Coloring performs a decorative function, and also indicates the percentage of alcohol. Usually there are anti-freezes with a bluish tint, which corresponds to a 25% concentration of isopropanol. An excess of dye leads to the formation of a precipitate. Therefore, its content should not exceed 0,001%.
Water
Deionized water is used without any impurities. Aqueous distillate acts as a heat carrier, solvent, and also removes contaminants along with surfactants. The percentage of water is 20-70% depending on the alcohol content.
Anti-freeze composition according to GOST
Currently in Russia there are no regulated documents on the composition and manufacture of windshield washer fluids. However, individual components are subject to regulatory requirements in accordance with the safety and effectiveness of the application. Approximate composition of winter windshield washer fluid with the PCT conformity mark according to the interstate standard (GOST):
- demineralized water: not less than 30%;
- isopropanol: more than 30%;
- Surfactants: up to 5%;
- stabilizer propylene glycol: 5%;
- water-dirt-repellent component: 1%;
- buffer agent: 1%;
- flavors: 5%;
- dyes: 5%.
Regulatory requirements for the composition
Product certification takes into account the degree of toxicity and performance of the product. So, windshield washers should effectively cope with pollution in winter, not form streaks, spots that limit the driver's view. The components in the composition must be indifferent to fiberglass and metal surfaces. Toxic compounds in the composition of the anti-freeze are replaced by harmless analogues: methanol - isopropanol, poisonous ethylene glycol - neutral propylene glycol.
