Method for coating of polystyrene particles

A method for providing expandable polystyrene beads with a coating,

• wherein the method comprises the step of subjecting a plurality of expandable polystyrene beads to a coating process in the presence of a coating agent, wherein during the coating process the coating agent is deposited on the surface of the expandable polystyrene beads such that the surface of the expandable polystyrene beads is coated at least essentially completely and homogeneously with the coating agent,
• wherein the coating agent comprises at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups;
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups fulfills at least one of the parameters (i), (ii) and (iii):
• (i) a hydroxyl-value (HV) in the range of from 100 to 500 mg KOH/g, determined according to method of DGF C-V 17a (21) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (ii) an acid value (AV) of at most 1 mg KOH/g, determined according to method of DGF C-V 2 (20) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (iii) a saponification value (SV) in the range of from 75 to 200 mg KOH/g, determined according to method of DGF C-V 3 (02) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]);
• and
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups corresponds to the following general formula (I)
• wherein, in the general formula (I),
• the variable p represents an integer from 1 to 5, and
• the radical R1, independently of one another, represents a radical selected from the group consisting of hydrogen and a saturated fatty acid radical;
• however, with the proviso that at least one radical R1 represents hydrogen and with the proviso that at least one radical R1 represents a fatty acid radical.

Expandable polystyrene beads provided with a coating,

• wherein the coating comprises at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups;
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups fulfills at least one of the parameters (i), (ii) and (iii):
• (i) a hydroxyl-value (HV) in the range of from 100 to 500 mg KOH/g, determined according to method of DGF C-V 17a (21) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (ii) an acid value (AV) of at most 1 mg KOH/g, determined according to method of DGF C-V 2 (20) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (iii) a saponification value (SV) in the range of from 75 to 200 mg KOH/g, determined according to method of DGF C-V 3 (02) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]);
• and
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups corresponds to the following general formula (I)
• wherein, in the general formula (I),
• the variable p represents an integer from 1 to 5, and
• the radical R1, independently of one another, represents a radical selected from the group consisting of hydrogen and a saturated fatty acid radical;
• however, with the proviso that at least one radical R1 represents hydrogen and with the proviso that at least one radical R1 represents a fatty acid radical.

A method for providing expandable polystyrene beads with a coating having at least one of an antistatic and antilumping effect,

• wherein the method comprising the step of using at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups as a coating agent for the expandable polystyrene beads, for providing expandable polystyrene beads with a coating having at least one of an antistatic and antilumping effect,
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups fulfills at least one of the parameters (i), (ii) and (iii):
• (i) a hydroxyl-value (HV) in the range of from 100 to 500 mg KOH/g, determined according to method of DGF C-V 17a (21) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (ii) an acid value (AV) of at most 1 mg KOH/g, determined according to method of DGF C-V 2 (20) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]),
• (iii) a saponification value (SV) in the range of from 75 to 200 mg KOH/g, determined according to method of DGF C-V 3 (02) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]);
• wherein the at least one partial polyglycerol ester of a saturated fatty acid which ester comprises free hydroxyl-groups corresponds to the following general formula (I)
• wherein, in the general formula (I),
• the variable p represents an integer from 1 to 5, and
• the radical R1, independently of one another, represents a radical selected from the group consisting of hydrogen and a saturated fatty acid radical;
• however, with the proviso that at least one radical R1 represents hydrogen and with the proviso that at least one radical R1 represents a fatty acid radical;
• wherein the coating does not comprise any metal compounds, and
• wherein the polystyrene beads have a mean particle diameter (D50) in the range of from 0.05 to 5 mm, determined according to ISO 13320:2020.