FIELD: chemistry.
SUBSTANCE: invention relates to particles, such as microparticles, and compositions, such as coating compositions and sealing compositions, which contain such particles. Disclosed is a particle whose outer surface is coated with a thin coating having film thickness of less than 25 mcm, wherein the (I) the thin coating contains a reaction product of (a) an aminoplastic resin and (b) a compound containing functional groups which are reactive with respect to the aminoplastic resin; or (II) the thin coating contains a sulphur-containing polymer. The compound (b) or sulphur-containing polymer contains thiol groups (polythiol, dithiol). The particle is a lightweight particle having specific weight of not more than 0.7 g/cm3 before applying the thin coating. The sulphur-containing polymer is a reaction product of the aminoplastic resin and a polyol, which preferably contains dithiol. The invention also relates to a method of using the particles, which involves adding the particles to a composition containing a binder in which the particles are dispersed. The invention also relates to a composition containing (a) a sulphur-containing polymeric binder; and (b) lightweight particles having specific weight of not more than 0.7 g/cm3 before applying the thin coating which are dispersed in the binder. The composition has specific weight of less than 1.0 or less than 0.9 or less than 0.85 g/cm3 and after deposition onto a substrate and curing turns into a curable composition which is characterised by: (i) swelling value of not more than 40 vol. % after immersion for one week at 140°F and ambient pressure in jet reference fluid (JRF) type 1; (ii) an elongation of at least 80% when measured according to AMS 3269a; and (iii) tensile strength of at least 2000 MPa when measured according to AS 5127/1a 7.7. The invention also relates to an aerospace vehicle having at least one slit sealed by a sealant made from said composition.
EFFECT: obtaining a composition which is capable of forming a film having resistance to weather elements such as moisture and temperature, and at least partially blocks such materials as water, fuel and other liquids and gases, and the curable sealant compositions have low temperature of elasticity and high tensile strength.
16 cl, 2 dwg, 4 tbl
