Porous coatings comprising minerals and an oxygen scavenger for improving food shelf life

A process for the manufacture of a kit for improving food shelf life, the process comprising the steps of:

• a) providing a particulate filler comprising more than 50 wt.-%, based on the total amount of filler, of a mineral preferably being an alkaline earth metal mineral, a silicate or a mixture thereof, wherein the mineral is not a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O+ ion donors, wherein the carbon dioxide is formed in situ by the H3O+ ion donors treatment and/or is supplied from an external source,
• b) providing at least one oxygen scavenger being a compound having at least one phenyl ring bearing at least two phenolic hydroxyl groups and at least one group R, wherein two of the at least two phenolic hydroxyl groups are positioned on the at least one phenyl ring in an ortho or para fashion relative to each other, and wherein R is selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an amino group, an alkyl group, an aryl group and a —Y—R1 group, preferably wherein R is a —Y—R1 group, wherein
• Y is selected from the group consisting of a direct bond, a linear or branched alkylene group having from 1 to 6 carbon atoms, and a —CH═CH— group, preferably Y is a direct bond, and
• R1 is an alkoxycarbonyl group, an aryloxycarboxyl group, a carboxyl group or an essentially fully deprotonated carboxyl group,
• c) providing a polymeric binder,
• d) providing a substrate layer comprising one or more individual substrate layers or a food packaging comprising the substrate layer,
• e) mixing, in the order set out herein, the oxygen scavenger of step b), the particulate filler of step a) and the polymeric binder of step c) to obtain a coating composition,
• f) applying the coating composition of step e) onto the substrate layer of step d) to obtain a sheet-like element precursor,
• g) drying the sheet-like element precursor obtained in step f) to obtain a sheet-like element component,
• h) providing an alkaline component comprising a base having a pKb value of 6 or lower, and optionally
• i) mixing the alkaline component of step h) with water to obtain an aqueous alkaline component comprising the base and water, wherein preferably
• the pH of the aqueous alkaline component is at least 8, more preferably at least 10, even more preferably at least 11, and most preferably at least 12 and/or
• the aqueous alkaline component comprises the base in an amount from 1 wt.-% to 75 wt.-%, more preferably 5 wt.-% to 60 wt.-%, and most preferably 10 to 35 wt.-%, based on the total weight of the aqueous alkaline component.

A process for the manufacture of a sheet-like element component, the process comprising the steps of:

• a) providing a particulate filler comprising more than 50 wt.-%, based on the total amount of filler, of a mineral preferably being an alkaline earth metal mineral, a silicate or a mixture thereof, wherein the mineral is not a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O+ ion donors, wherein the carbon dioxide is formed in situ by the H3O+ ion donors treatment and/or is supplied from an external source,
• b) providing at least one oxygen scavenger being a compound having at least one phenyl ring bearing at least two phenolic hydroxyl groups and at least one group R, wherein two of the at least two phenolic hydroxyl groups are positioned on the at least one phenyl ring in an ortho or para fashion relative to each other, and wherein R is a —Y—R1 group, wherein
• Y is selected from the group consisting of a direct bond, a linear or branched alkylene group having from 1 to 6 carbon atoms, and a —CH═CH— group, preferably Y is a direct bond, and
• R1 is an essentially fully deprotonated carboxyl group
• c) providing a polymeric binder,
• d) providing a substrate layer comprising one or more individual substrate layers or a food packaging comprising the substrate layer,
• e) mixing, in the order set out herein, the oxygen scavenger of step b), the particulate filler of step a), and the polymeric binder of step c) to obtain a coating composition,
• f) applying the coating composition of step e) onto the substrate layer of step d) to obtain a sheet-like element precursor, and
• g) drying the sheet-like element precursor obtained in step f) to obtain a sheet-like element component,
• wherein step b) of providing the at least one oxygen scavenger comprises the sub-steps of b1) providing at least one oxygen scavenger precursor being a compound having at least one phenyl ring bearing at least two phenolic hydroxyl groups and at least one group R, wherein two of the at least two phenolic hydroxyl groups are positioned on the at least one phenyl ring in an ortho or para fashion relative to each other, and wherein R is a —Y—R1 group, wherein
• Y is selected from the group consisting of a direct bond, a linear or branched alkylene group having from 1 to 6 carbon atoms, and a —CH═CH— group, preferably Y is a direct bond, and
• R1 is a carboxyl group,
• b2) providing a basic compound, and
• b3) reacting the carboxyl group of the oxygen scavenger precursor of step b1) with the basic compound of step b2) to obtain the oxygen scavenger.