	US 11,969,753 B2
	Process for producing matt coatings on sheetlike substrates
Axel Becker, Ludwigshafen (DE); Sebastian Berger, Ludwigshafen (DE); and Stefanie Stein, Ludwigshafen (DE)
Assigned to BASF SE, Ludwigshafen am Rhein (DE)
Appl. No. 16/637,071
Filed by BASF SE, Ludwigshafen am Rhein (DE)
PCT Filed Aug. 15, 2018, PCT No. PCT/EP2018/072088 § 371(c)(1), (2) Date Feb. 6, 2020, PCT Pub. No. WO2019/034675, PCT Pub. Date Feb. 21, 2019.
Claims priority of application No. 17186474 (EP), filed on Aug. 16, 2017.
Prior Publication US 2023/0256468 A1, Aug. 17, 2023
Int. Cl. B05D 3/06 (2006.01); C09D 163/10 (2006.01); C09D 167/07 (2006.01); C09D 171/00 (2006.01)

CPC B05D 3/067 (2013.01) [C09D 163/10 (2013.01); C09D 167/07 (2013.01); C09D 171/00 (2013.01)]

19 Claims

1. A method for producing matt coatings on sheetlike substrates, comprising the consecutive steps i.-iv.,

i. providing an uncured coating film of a liquid coating formulation F, curable by UV radiation, on the surface of the substrate to be coated;

ii. irradiating the coating film with UV radiation which lies substantially in the wavelength range from 250 to 420 nm, with a radiation dose which leads to partial curing of the coating film;

iii. irradiating the partially cured coating film with UV radiation in the wavelength range from 150 to <250 nm under inert gas;

iv. irradiating the partially cured coating film with UV radiation which lies substantially in the wavelength range from 250 to 420 nm, or with electron beams, with a radiation dose which leads to full curing of the coating film;

wherein the coating formulation F comprises at least 80 wt %, based on the total weight of the coating-forming constituents of the coating formulation F, of one or more curable constituents which have ethylenically unsaturated double bonds,

the coating formulation F further comprising at least one photoinitiator, wherein the coating formulation F comprises at least one oligomer or polymer which carries on average at least 1.5 ethylenic double bonds per molecule and has a number-average molecular weight M_nof at least 450 daltons, and

the coating formulation F fulfills at least the following features (A) and (B) or (A) and (C) and optionally (D):

(A) the number of ethylenically unsaturated double bonds, based on the coating-forming constituents present in the coating formulation F, is in the range from 3.0 to 8.0 mol/kg;

(B) the coating formulation F comprises at least 30 wt %, based on the curable constituents present therein, of an oligomer or polymer or of a mixture of oligomers and/or polymers wherein the ratio α/T_oof calculated network arc length α in g/mol to the onset temperature T_oin kelvins of the glass transition, determined by means of differential scanning calorimetry according to DIN EN ISO 11357-2:2014, is at least 1.2;

(C) the mass-average ratio α/T_o, averaged over the weight fractions of all curable constituents of the coating formulation F, is at least 1.0;

(D) the coating formulation F comprises at least one aromatic epoxy acrylate in an amount of at least 20 wt %, based on the total weight of the curable constituents present in the coating formulation F.