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Title:
PROCESS FOR IMPARTING GREASE, OIL AND WATER REPELLENCE TO SUBSTRATES
Document Type and Number:
WIPO Patent Application WO/2019/081258
Kind Code:
A1
Abstract:
The invention pertains to a process for imparting grease, oil and water repellence to a substrate, said process comprising applying on at least a portion of the surface of said substrate a composition comprising: - at least one vinylidene chloride polymer; - at least one polysaccharide compound; and - at least one vinyl alcohol polymer.

Inventors:
LAM, Minhdung (311 Patsy Court, West Deptford, New Jersey, 08066, US)
CLYMER, Rebecca, Nandi (3739 Lankenau Rd, Philadelphia, PA, 19131, US)
SICILIANO, Robert, James (671 National Hwy, LaVale, MD, 21502, US)
Application Number:
EP2018/078131
Publication Date:
May 02, 2019
Filing Date:
October 16, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SOLVAY SA (Rue de Ransbeek, 310, 1120 Bruxelles, 1120, BE)
International Classes:
C09D127/08; C08L1/00; C08L3/00; C08L5/00; C08L29/04
Domestic Patent References:
WO2011056130A12011-05-12
Foreign References:
CN106868690A2017-06-20
CN104293060A2015-01-21
JPH11279357A1999-10-12
EP1273704A12003-01-08
EP1369442A12003-12-10
US5691000A1997-11-25
EP1138826A22001-10-04
EP1371676A12003-12-17
EP1484445A12004-12-08
EP1489124A12004-12-22
US3162543A1964-12-22
Attorney, Agent or Firm:
BENVENUTI, Federica (Rue de Ransbeek, 310, 1120 BRUXELLES, 1120, BE)
Download PDF:
Claims:
Claims

Claim 1. A process for imparting grease, oil and water repellence to a

substrate, said process comprising applying on at least a portion of the surface of said substrate a composition comprising:

- at least one vinylidene chloride polymer [polymer (VDC)];

- at least one polysaccharide compound [polymer (S)]; and

- at least one vinyl alcohol polymer [polymer (OH)].

Claim 2. The process of Claim 1 , wherein the amount of recurring units

derived from vinylidene chloride in the polymer (VDC) varies from 50 to 99.5 wt%, preferably from 60 to 98 wt%, more preferably from 82 to 93 wt%, and most preferably from 85 to 90 wt% of the polymer (VDC).

Claim 3. The process of anyone of the preceding claims, wherein polymer (S) is selected from polysaccharides, that is to say polymers having recurring units derived from carbohydrate or carbohydrate derivatives, and polysaccharide derivatives obtained by modification/derivatization of the said polysaccharides.

Claim 4. The process of claim 3, wherein:

(i) polysaccharides are selected from the group consisting of:

- celluloses, i.e. polymers comprising repeat units derived from D-glucose, in its beta-pyranose structure (i.e. beta-D-gluocopyranosyl units), which are joined by (1→4) glycosidic linkage, or, in other words, which comprise sequences of (1→4) linked beta-D-gluocopyranosyl units;

- starches, i.e. mixtures of amylose, linear polysaccharide of (1→4) linked alpha-D-gluocopyranosyl units, and amylopectine, branched polysaccharide comprising sequences of (1→4) linked alpha-D-gluocopyranosyl units, with branches joining the said sequences through (1→6) linked alpha-D- glucopyranosyl units;

- algins, i.e. polysaccharides of D-mannuronic acid and L-guluronic acid, generally in their salified form;

- carrageenans, i.e. polysaccharides including sequences of beta-D- galactopyranosyl units, and including units of anhydro-derivative thereof, such as e.g. units of 3,6-anhydro-alpha-D-galactopyranose or units of 3,6-anhydro- alpha-L-galactopyranose; - guar gums, i.e. polysaccharides including sequences of (1→4) linked beta-D- mannopyranosyl units, possibly substituted with (1→6) linked beta-D- mannopyranosyl units;

- pectins, i.e. polysaccharides comprising sequences of (1→4) linked alpha-D- galactopyranosyluronic, whereas some of the carboxyl groups of the uronic acid may be under the form of alkyl esters;

- xanthan gums, i.e. polysaccharides comprising main chains made of sequences of (1→4) linked beta-D-glucopyranosyl units, whereas about every other beta-D-glucopyranosyl unit in the main chain is substituted on O-3 with an trisaccharide unit consisting of a beta-D-mannopyranosyl unit linked (1→4) to a beta-D-glucopyranosyluronic acid unit, linked (1→2) to a 6-O-acetyl-alpha- D-mannopyranosyl unit; and

(ii) polysaccharide derivatives are selected from the group consisting of carboxymethylcelluloses, cellulose acetates, cellulose acetate butyrate, cellulose nitrate, ethylcelluloses, hydroxyalkylcelluloses,

hydroxyalkylalkylcelluloses, methylcelluloses, starch acetates, starch adipates, starch 1-octenylsuccinates, starch phosphates, starch succinates,

carboxymethylstarches, hydroxyethylstarches, hydroxypropylstarches, cationic starches, oxidized starches carboxymethylguar gums,

carboxymethyl(hydroxypropyl)guar gums, hydroxyethyl guar gums,

hydroxypropyl guar gum, 2-hydroxy-3-(trimethylammonio)propyl guar gum and other cationic guar gums, sodium alginates, calcium alginates, methoxy pectins, sodium pectates, calcium pectate.

Claim 5. The process of anyone of the preceding claims, wherein

composition (C) comprises polymer (S), polymer (OH) and polymer (VDC) in a liquid carrier, and wherein the liquid carrier is preferably an aqueous medium.

Claim 6. The process of Claim 5, wherein the polymer (S), polymer (OH) and polymer (VDC) may be solubilized or emulsified in the aqueous medium.

Claim 7. The process of Claim 6, wherein polymer (VDC) is present in an

emulsified form, with stably dispersed particles having a particle size of at most 500 nm, preferably at most 450 nm, more preferably at most 400 nm and/or of at least 50 nm, preferably at least 75 nm, more preferably at least 100 nm. Claim 8. The process of anyone of claims 5 to 7, wherein the composition (C) comprises polymer (S), polymer (OH) and polymer (VDC) in an aqueous medium in the following amounts:

- from 3 to 40 % wt, preferably from 5 to 36 % wt of polymer (VDC);

- from 0.1 to 10 % wt, preferably from 0.5 to 8 % wt of polymer (OH); and

- from 0.1 to 7 % wt, preferably from 0.2 to 5 % wt of polymer (S),

wherein the %wt are referred to the total weight of the composition,

comprehensive of the aqueous medium; or

wherein the composition (C) comprises polymer (S), polymer (OH), polymer (VDC) and emulsifier (E) in an aqueous medium in the following amounts:

- from 3 to 40 % wt, preferably from 5 to 36 % wt of polymer (VDC);

- from 0.1 to 10 % wt, preferably from 0.5 to 8 % wt of polymer (OH); and

- from 0.1 to 7 % wt, preferably from 0.2 to 5 % wt of polymer (S);

- from 0.05 to 4 % wt, preferably from 0.1 to 3 % wt of emulsifier (E);

wherein the %wt are referred to the total weight of the composition,

comprehensive of the aqueous medium.

Claim 9. The process according to anyone of claims 5 to 8, wherein the

composition (C) possesses a liquid viscosity of at least 10, at least 15, preferably at least 20 mPa.sec, when measured at 25°C, using a Brookfield viscometer operating at 100 rpm, and/or a liquid viscosity of at most 150, at least 125, preferably at most 100 mPa.sec, when measured at 25°C, using a Brookfield viscometer operating at 100 rpm.

Claim 10. The process according to anyone of the preceding claims, wherein the substrate is selected from the group of cellulose substrates, and wherein said cellulose substrates are preferably selected from paper, paper boards and other cellulosic fibres assemblies.

Claim 1 1. The process according to anyone of the preceding claims, wherein composition (C) is applied on at least a portion of the surface of the said cellulose substrate in size-press treatment, coating treatment, calender water box treatment or in wet-end treatment in the paper machines.

Claim 12. The process of Claim 1 1 , wherein the composition is applied in wet- end treatment of a paper machine comprising a head box which is fed with a fibres suspension, a wire section whereas the said dispersion is fed onto a fine mesh through which water drains to provide for a wet fibres web of paper, a press section and a drier section, and wherein the composition (C) is introduced in the initial fibres suspension dispersion and caused to deposit onto the fibres during web formation.

Claim 13. The process of Claim 1 1 , wherein the composition is applied in wet- end treatment of a paper machine comprising a head box which is fed with a fibres suspension, a wire section whereas the said dispersion is fed onto a fine mesh through which water drains to provide for a wet fibres web of paper, a press section and a drier section, and wherein the composition (C ) is applied in the size-press treatment, and wherein the composition (C) is caused to impregnate the fibres web of paper by passing this latter into a sizing liquid pond located above a roll nip, so as the paper web absorbs the sizing liquor including the composition (C).

Claim 14. The process of claim 1 1 , wherein composition (C) is applied in a

coating treatment of a paper machine comprising a head box which is fed with a fibres suspension, a wire section whereas the said dispersion is fed onto a fine mesh through which water drains to provide for a wet fibres web of paper, a press section and a drier section, and wherein the composition (C), and wherein the composition (C) is caused to impregnate the fibres web of paper by passing this latter through a coater, typically rod or metering blade.

Claim 15. The process of Claim 1 1 , wherein composition (C) is applied to at least a part of the cellulose surface through a printing process, preferably through a printing technique based on transfer of the composition (C) to the cellulose substrate from engraved or depressed surfaces (intaglio techniques), in particular through gravure or flexographic method.

Description:
Description

Process for imparting grease, oil and water repellence to substrates

[0001] This application claims priority to U.S. provisional application

No. 62/577156 filed on 25.10.2017, the whole content of this application being incorporated herein by reference for all purposes.

Technical Field

[0002] This invention pertains to an improved method for conferring grease, oil and water repellence to substrates, involving the use of certain

compositions.

Background Art

[0003] Additivation/surface treatment of substrates, in particular packaging

substrates (e.g. cellulosic substrates), with different chemicals to impart grease, oil, wax and solvent repellence has been known for some time.

[0004] These additives are used for the manufacture of substrates suitable to be used with fat foods for short periods (clamshells or bags for hamburger, fast food products, pop-corn, small cardboard tubs for chips, etc.) and for longer periods (flexible packages for fat foods, food for dogs and cats, biscuits, etc.).

[0005] Among commercially available fluorochemical modifiers well-suited for this application, those based on (per)fluoropolyethers have drawn increased attention, due to their better HSE and toxicological profile with respect to perfluoroalkyl-containing counterparts and their acceptable oil and water repellence properties.

[0006] Among techniques for conferring oleo-repellence to substrates, in

particular cellulosic substrates, treatments with fluorochemicals, e.g.

(per)fluoropolyether derivatives comprising perfluorooxyalkylenic chains in a polyurethane backbone (see e.g. EP 1273704 A (AUSIMONT SPA (IT)) 8/01/2003 and EP 1369442 A (2003-12-10) 10/12/2003 or with

(per)fluoropolyether derivatives comprising phosphate groups (as taught e.g. in US 5691000 (AUSIMONT SPA (IT)) 25/1 1/1997, EP 1 138826 A (AUSIMONT SPA (IT)) 4/10/2001 , EP 1273704 A (AUSIMONT SPA (IT)) 8/01/2003, and EP 1371676 A (SOLVAY SOLEXIS S.P.A.) 17/12/2003 or with (per)fluoropolyether derivatives having carboxyl groups (as shown in EP 1484445 A (SOLVAY SOLEXIS SPA (IT)) 8/12/2004 and

EP 1489124 A (SOLVAY SOLEXIS SPA (IT)) 22/12/2004 are known.

[0007] While fluorochemicals-based solutions have proven to be very effective, costs of fluorochemical specialities and, now and then, environmental concerns in connection with certain molecules are creating need for alternative solutions which are fluorine-free.

[0008] On the other side, methods based on the use of mixtures including

thermoplast resins are also known in the art. Among those approaches for modifying surface properties of cellulosic surfaces, mention can be notably made of US 3162543 (OWENS ILLINOIS GLASS COMPANY) 22/12/1964 which discloses a cellulosic material having an anti-stick and bleed-proof coating thereon, which coating comprises a mixture of a silicone

compound and a film-forming material consisting of acetylated starch and a thermoplastic resin selected from the group consisting of polyvinyl acetate, polymethyl methacrylate, polyethyl methacrylate, ethyl-methyl methacrylate, polyvinyl chloride, polyvinylidene chloride, vinyl acetate vinyl stearate copolymer, butadiene-acrylonitrile copolymer, vinyl chloride- vinylidene chloride copolymer, and butadiene-styrene copolymer. A two- coatings solution including a first coating of acetylated starch and a thermoplastic resin, over-coated with a second coating including same ingredients and further including silicone resin is provided.

[0009] Need is thus felt to provide a novel method for imparting oil and water repellence to substrates, in particular packaging substrates which would provide an alternative solution to fluorine-based modifications, for coping with circumstances where fluoromaterial-based solutions are not practicable/acceptable including for cost reasons.

Disclosure of Invention

[0010] It is thus an object of the present invention a process for imparting grease, oil and water repellence to a substrate, said process comprising applying on at least a portion of the surface of said substrate a composition comprising:

- at least one vinylidene chloride polymer [polymer (VDC), herein after];

- at least one polysaccharide compound [polymer (S), hereinafter]; and

- at least one vinyl alcohol polymer [polymer (OH), herein after].

[001 1] The Applicant has found that by means of the process of the invention it is possible to confer suitable grease, oil and water repellence properties to substrates, without the use of fluoro-containing additives, achieving outstanding performances, as required for the target applications.

[0012] The expressions "vinylidene chloride polymer" and "polymer (VDC)" are used hereby as synonyms to designate a polymer of which at least 50% by weight (wt%) of recurring units are derived from vinylidene chloride, with respect to the total weight of polymer (VDC). Typically, the amount of recurring units derived from vinylidene chloride in the vinylidene chloride polymer varies from 50 to 99.5 wt%, preferably from 60 to 98 wt%, more preferably from 82 to 95 wt%, and most preferably from 85 to 93 wt% of the polymer (VDC).

[0013] The vinylidene chloride homopolymer is hardly processible and generally copolymers are deemed as more commercially important, emulsion and suspension polymerisation being the preferred industrial manufacturing processes. Vinylidene chloride polymer hence generally comprises recurring units derived from at least one additional ethylenically

unsaturated monomer copolymerisable with vinylidene chloride, for the purpose of having better processibility and improved solubility in most solvents commonly used in this field.

[0014] Non-limiting examples of at least one ethylenically unsaturated monomer copolymerisable with vinylidene chloride that can be used include, for instance, vinyl chloride; vinyl esters, such as vinyl acetate; vinyl ethers; acrylic acids, their esters and amides; methacrylic acids, their esters and amides; acrylonitrile; methacrylonitrile; styrene; styrene derivatives, such as styrene sulfonic acid and its salts; vinyl phosphonic acid and its salts; butadiene; olefins, such as ethylene and propylene; itaconic acid, and maleic anhydride. [0015] Preferably, the said ethylenically unsaturated monomer copolymerisable with vinylidene chloride is selected from the group consisting of vinyl chloride, maleic anhydride, itaconic acid, styrene, styrene derivatives, and the acrylic or methacrylic monomers corresponding to general formula (I): CH 2 = CRi R 2 (I)

wherein Ri is chosen from hydrogen and -CH3 and R2 is chosen from -CN and -COR3, wherein R3 is chosen from -OH and -OR 4 , wherein R 4 is a Ci- C18 linear or branched alkyl group optionally bearing one or more -OH groups, a C2-C10 epoxy alkyl group and a C2-Cio alkoxy alkyl group, and wherein R3 is also chosen from the -NR5R6 radicals, in which R5 and R6, same or different, are chosen from hydrogen and C1-C10 alkyl groups, optionally bearing one or more -OH groups.

[0016] More preferably, the said ethylenically unsaturated monomer

copolymerisable with vinylidene chloride is selected from the group consisting of vinyl chloride, maleic anhydride, itaconic acid, the acrylic or methacrylic monomers selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide, N-methylolacrylamide, and N,N- di(alkyl)acrylamide.

[0017] Even more preferably, the said ethylenically unsaturated monomer

copolymerisable with vinylidene chloride is selected from the group consisting of maleic anhydride, itaconic acid, the acrylic or methacrylic monomers selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2- hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide, N-methylolacrylamide, and N,N-di(alkyl)acrylamide.

[0018] Most preferably, the said ethylenically unsaturated monomer

copolymerisable with vinylidene chloride is selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide,

N-methylolacrylamide, and N,N-di(alkyl)acrylamide.

[0019] Typically, the amount of recurring units derived from the said ethylenically unsaturated monomer copolymerisable with vinylidene chloride in the vinylidene chloride polymer varies from 0.5 to 50 wt%, preferably from 2 to 40 wt%, more preferably from 5 to 18 wt%, and most preferably from 7 to 15 wt%, with respect to the total weight of polymer (VDC).

[0020] Polymer (VDC) is generally present in the composition (C) under the form of discrete particles; the said particles may be dispersed in a liquid carrier, or may be solubilized in the same. Generally, particles of polymer (VDC) are dispersed in a liquid medium under the form of a latex, i.e. in an emulsified form, with stably dispersed particles having a particle size of at most 500 nm, preferably at most 450 nm, more preferably at most 400 nm and/or of at least 50 nm, preferably at least 75 nm, more preferably at least 100 nm.

[0021] The expression "polysaccharide compound" or "polymer (S)" is hereby used according to its usual meaning, i.e. to encompass polysaccharides, that is to say polymers having recurring units derived from carbohydrate or carbohydrate derivatives, and polysaccharide derivatives obtained by modification/derivatization of the said polysaccharides.

[0022] A carbohydrate is an organic molecule possessing an aldehyde group or a ketone group, and further comprising a hydroxyl group on every carbon atom other than the aldehyde or ketone carbon atom. Aldoses are carbohydrates having aldehyde carbonyl group, and ketoses are carbohydrates having ketone carbonyl group. Generally, hence, the formula for basic carbohydrates is C n (H2O) n : these compounds contain hydrogen and oxygen in the ratio in which they are found in water, which is the origin of their name, carbohydrate being to be understood as hydrate of carbon. [0023] Among aldoses, mention can be made of D-erythrose, D-ribose, D- arabinose, D-allose, D-altrose, D-gluocose, D-mannose, D-threose, D- xylose, D-lyxose, D-gulose, D-idose, D-galactose, D-talose, as well as corresponding L-configuration compounds (which are generally quite rarely occurring in natural polysaccharides, except for L-arabinose), and all corresponding furanose and pyranose compounds, where cyclization is possible.

[0024] Among ketoses, mention can be made of D-erythrulose; D-ribulose; D- xylulose; D-psicose; D-fructose; D-sorbose; D-tagatose, D-manno- octulose, as well as corresponding L-configuration compounds.

[0025] Indeed, most carbohydrates are comprised in polysaccharides in their

cyclic form, e.g. a 6-membered ring, referred to as "pyranose" or a 5- membered ring, referred to as "furanose", through reaction of a hydroxyl group with the ketone or aldehyde group and formation of corresponding hemiacetal bond.

[0026] Carbohydrate derivatives are compounds which derive from carbohydrates through introduction of functional groups other that the hydroxyl group, aldehyde group and ketone group, or corresponding hemiacetal groups. Among carbohydrate derivatives, mention can be made of:

- anhydro-derivatives, possessing an intra-molecule ethereal bridge through condensation between two distal hydroxyl group, such as e.g. 3,6- anhydro-L-galactopyranose, which is the pyranose cycle of an L-galactose with an anhydro bridge between the carbon atoms in 3 and 6 position;

- aldonic acids, which are aldoses whereas the aldehyde group has been oxidized to a carboxylic acid group, such as e.g. D-gluconic acid;

- uronic acids, which are aldoses or ketoses whereas the distal carbon atoms bearing the hydroxyl group has been oxidized to a carboxylic acid group, such as e.g. D-glucuronic acid, derived from D-glucose, D-guluronic acid, derived from D-gulose, D-mannuronic acid, derived from D-mannose; D-galacturonic acid from D-galactose, and corresponding cyclic forms including e.g. D-galactopyranosyluronic acid;

- aldonic acids, which are aldoses whereas both the aldehyde group has been oxidized to a carboxylic acid group and the distal carbon atoms bearing the hydroxyl group has been oxidized to a carboxylic acid group;

- ulosonic acids, which are 2-ketoses whereas the first carbon bearing a hydroxyl group has been oxidized to a carboxylic acid group, so providing for an alpha-keto-acid, such as e.g. 3-deoxy-D-manno-oct-2-ulosonic acid, deriving from D-manno-octulose.

[0027] Polysaccharide derivatives can obtained by modification/derivatization of the said polysaccharides chosen from the group consisting of:

- salification;

- acetylation;

- nitration;

- esterification:

- etherification;

- oxidation.

[0028] The mentioned modification/derivatization may introduce in the

polysaccharide ionisable groups, such as e.g. tertiary amino or quaternary ammonium groups.

[0029] Among polysaccharides which can be used in the composition of the

present invention, mention can be made of:

- celluloses, i.e. polymers comprising repeat units derived from D-glucose, in its beta-pyranose structure (i.e. beta-D-gluocopyranosyl units), which are joined by (1→4) glycosidic linkage, or, in other words, which comprise sequences of (1→4) linked beta-D-gluocopyranosyl units;

- starches, i.e. mixtures of amylose, linear polysaccharide of (1→4) linked alpha-D-gluocopyranosyl units, and amylopectine, branched

polysaccharide comprising sequences of (1→4) linked alpha-D- gluocopyranosyl units, with branches joining the said sequences through (1→6) linked alpha-D-glucopyranosyl units;

- algins, i.e. polysaccharides of D-mannuronic acid and L-guluronic acid, generally in their salified form;

- carrageenans, i.e. polysaccharides including sequences of beta-D- galactopyranosyl units, and including units of anhydro-derivative thereof, such as e.g. units of 3,6-anhydro-alpha-D-galactopyranose or units of 3,6- anhydro-alpha-L-galactopyranose; - guar gums, i.e. polysaccharides including sequences of (1→4) linked beta-D-mannopyranosyl units, possibly substituted with (1→6) linked beta- D-mannopyranosyl units;

- pectins, i.e. polysaccharides comprising sequences of (1→4) linked alpha-D-galactopyranosyluronic, whereas some of the carboxyl groups of the uronic acid may be under the form of alkyl esters, e.g. methyl ester form;

- xanthan gums, i.e. polysaccharides comprising main chains made of sequences of (1→4) linked beta-D-glucopyranosyl units, whereas about every other beta-D-glucopyranosyl unit in the main chain is substituted on O-3 with an trisaccharide unit consisting of a beta-D-mannopyranosyl unit linked (1→4) to a beta-D-glucopyranosyluronic acid unit, linked (1→2) to a 6-O-acetyl-alpha-D-mannopyranosyl unit.

[0030] Among polysaccharide derivatives which can be used in the composition (C) as above detailed, mention can be notably made of

carboxymethylcelluloses, cellulose acetates, cellulose acetate butyrate, cellulose nitrate, ethylcelluloses, hydroxyalkylcelluloses,

hydroxyalkylalkylcelluloses, methylcelluloses, starch acetates, starch adipates, starch 1-octenylsuccinates, starch phosphates, starch

succinates, carboxymethylstarches, hydroxyethylstarches,

hydroxypropylstarches, cationic starches, oxidized starches

carboxymethylguar gums, carboxymethyl(hydroxypropyl)guar gums, hydroxyethyl guar gums, hydroxypropyl guar gum, 2-hydroxy-3- (trimethylammonio)propyl guar gum and other cationic guar gums, sodium alginates, calcium alginates, methoxy pectins, sodium pectates, calcium pectate.

[0031] The expression "at least one vinyl alcohol polymer" or "polymer (OH)" is intended to designate a polymer comprising a majority of recurring units of formula -CH 2 CH(OH)-.

[0032] Polymer (OH) can be derived from the hydrolysis of a variety of polyvinyl esters) such as polyvinyl acetate), polyvinyl formate), and polyvinyl benzoate) and from the hydrolysis of polyvinyl ethers). However, it is generally understood that polymer (OH) is preferably manufactured by the hydrolysis of polyvinyl acetate). Generally, polymer (OH) is hence substantially comprised of recurring units of formula -CH2CH(OH)-, i.e. is a homopolymer.

[0033] Polymer (OH) may be also selected from copolymers, in particular

copolymers with ethylene or with methylmethacrylate, although

homopolymers are preferred.

[0034] Substrates used in the process of the invention are typically those used in packaging applications, comprising, notably cellulose substrates, which are indeed those preferred.

[0035] The composition used in the process of the invention typically comprises the aforementioned polymer (S), polymer (OH) and polymer (VDC) in a liquid carrier.

[0036] Generally, the liquid carrier is an aqueous medium, i.e. a medium

comprising water as major component (> 50 % wt). Compositions of the invention comprising an aqueous medium are generally preferred when environmental impact is considered.

[0037] The polymer (S), polymer (OH) and polymer (VDC) may be solubilized or emulsified in the aqueous medium of this embodiment. The aqueous medium may optionally comprise a polar organic solvent, e.g. at least one of alcohols, glycols, ethers. As alcohols, isopropanol, ethanol, methanol, t- butanol can be used; as ethers, mention can be made of dipropylenglycol monomethylether; as glycols, ethylene or propylene glycols can be mentioned.

[0038] Optionally, the composition may comprise additional components or

ingredients.

[0039] In particular, the composition may comprise at least one emulsifier

[emulsifier (E)]. The choice of emulsifiers (E) is not specifically limited. In certain embodiments, natural compounds possessing emulsifying ability may be used, such as notably lecithin, natural mono- and diglycerides, sorbitan fatty acid esters, poly(oxyethylene sorbitan esters, and

phospholipids and the like. Generally, emulsifiers (E) are used when the composition (C) is an aqueous composition. In those cases, when emulsifiers (E) are used, they are comprised in composition (C) in an amount of generally at least 0.01 % wt, preferably at least 0.05 % wt, more preferably at least 0.1 % wt and/or generally at most 5 % wt, preferably at most 4 % wt, more preferably at most 3 % wt, with respect to the total weight of the composition (C).

[0040] An emulsifier which has provided particularly good results is lecithin, in particular soy lecithin.

[0041] The composition may optionally comprise a pigment or a dye. Suitable pigments include kaolin clay, delaminated clays, structured clays, calcined clays, alumina, silica, aluminosilicates, talc, calcium sulfate, ground calcium carbonates, and precipitated calcium carbonates. Suitable dyes are typically organic dyes, comprising e.g. chormophores, like, for instance, derivates of acridine, anthraquinone, diphenyl or

triphenylmethane, azo-compounds, nitro- or nitroso-substituted

compounds, quinone, phthalocyanines, thiazin, thiazole, oxazin, oxazone, xanthene, fluorine.

[0042] Also, the composition may comprise other additives including clays,

dispersants, lubricants, defoamers, film-formers, antifoamers and crosslinkers.

[0043] The composition (C) generally comprises polymer (S), polymer (OH) and polymer (VDC) in an aqueous medium.

[0044] According to this preferred embodiment, composition (C) comprises:

- from 3 to 40 % wt, preferably from 5 to 36 % wt of polymer (VDC);

- from 0.1 to 10 % wt, preferably from 0.5 to 8 % wt of polymer (OH); and

- from 0.1 to 7 % wt, preferably from 0.2 to 5 % wt of polymer (S), wherein the %wt are referred to the total weight of the composition, comprehensive of the aqueous medium.

[0045] Still, preferred embodiments whereas the composition (C) further

comprises an emulsifier are those wherein the composition (C) comprises polymer (S), polymer (OH), polymer (VDC) and emulsifier (E) in an aqueous medium in the following amounts:

- from 3 to 40 % wt, preferably from 5 to 36 % wt of polymer (VDC);

- from 0.1 to 10 % wt, preferably from 0.5 to 8 % wt of polymer (OH); and

- from 0.1 to 7 % wt, preferably from 0.2 to 5 % wt of polymer (S); - from 0.05 to 4 % wt, preferably from 0.1 to 3 % wt of emulsifier (E);

wherein the %wt are referred to the total weight of the composition, comprehensive of the aqueous medium.

[0046] To the sake of ensuring suitable coated weight on the support, the

composition (C) possesses a liquid viscosity of at least 10, at least 15, preferably at least 20 mPa.sec, when measured at 25°C, using a

Brookfield viscometer operating at 100 rpm.

[0047] Conversely, in order to ensure acceptable liquid processability in liquid processing, it is generally preferred for composition (C) of possessing a liquid viscosity of at most 150, at least 125, preferably at most 100 mPa.sec, when measured at 25°C, using a Brookfield viscometer operating at 100 rpm.

[0048] In the process of the invention, the composition (C) as above detailed is applied on at least a portion of the surface of said cellulose substrate.

[0049] Cellulose substrates include notably all types and kinds of cellulose- containing materials, including notably paper (e.g. kraft paper), paper boards (e.g. solid bleached sulphite paper board) and other cellulosic fibers assemblies.

[0050] Composition (C) is generally applied on at least a portion of the surface of the said cellulose substrate in size-press treatment, coating treatment, calender water box treatment or in wet-end treatment in the paper machines.

[0051] A paper machine is actually a large de-watering device consisting

generally of a head box, a wire section, press section and dryer section wherein starting from a dilute suspension of fibres, and possibly fillers, dyes and other chemicals, which is homogenously fed onto a fine mesh through which the water drains, the fibres web is conveyed onto

subsequent pressing and drying stages.

[0052] In the wet-end treatment, the composition (C) is introduced in the initial fibres suspension dispersion and caused to deposit onto the fibres during web formation.

[0053] When used in the size-press treatment, the composition (C) is caused to impregnate the fibres web of paper by passing this latter into a sizing liquid pond located above a roll nip. As a result, the paper web absorbs the sizing liquor including the composition (C).

[0054] When used in a coating treatment, the composition (C) is caused to

impregnate the fibres web of paper by passing this latter through a coater, typically rod or metering blade. As a result, a thin film of coating of the composition (C) is applied to the surface of the paper web.

[0055] When used in a calendar water box, the composition (C) is caused to

impregnate the fibres web of paper by passing this latter through a calender stack equipped with a water box. The water box applies a dilute solution of composition (C) to the calender roll which is then transferred to the paper web.

[0056] As an alternative, composition (C) is applied to at least a part of the paper surface through a printing process.

[0057] The term 'printing process' is hereby intended to denote any kind of

process which enables selectively applying a chemical on a pre-formed cellulose substrate surface according to a pre-determined pattern.

[0058] The printing process also advantageously comprises a drying step; in this step the composition (C) applied onto the substrate is dried, that is to say all volatile components (e.g. the liquid carrier,...) are eliminated.

[0059] Said drying step might be performed by different means; among others, mention can be made of heated rolls, hot air ovens, IR driers of UV driers.

[0060] In the case of UV driers, simultaneously to drying, UV-catalyzed

crosslinking may be obtained, in case the composition comprises derivatives comprising UV-crosslinkable moieties.

[0061] Among printing techniques, those based on transfer of the composition to the cellulose substrate from engraved or depressed surfaces (intaglio techniques) are preferred. Among them mention can be made of gravure and flexographic methods.

[0062] It should be outlined that these intaglio printing processes are preferred as they are particularly suitable for transferring into cellulose substrates compositions having low viscosity, such as those used in the invention, and are compatible with aqueous media. [0063] Gravure printing typically uses a depressed or sunken surface for the pattern to be reproduced on the cellulose substrate. The pattern areas consist generally of honey comb shaped cells or wells that are etched or engraved into a cylinder, typically a metal cylinder (copper being

preferred). The unetched areas of the cylinder represent the non-image or unprinted areas. The cylinder usually rotates in a bath of liquid

composition, typically called the 'ink pan'.

[0064] As the engraved cylinder turns, the excess composition is generally wiped off the cylinder by a flexible doctor blade. The composition remaining in the recessed cells advantageously forms the pattern by direct transfer to the substrate (paper or other material) as it passes between the engraved cylinder and an impression cylinder, typically rubber coated.

[0065] Flexography, which is the major process used to print packaging materials, e.g. corrugated containers, folding cartons, multiwall sacks, paper sacks, plastic bags, milk and beverage cartons, disposable cups and containers, labels, adhesive tapes, envelopes, newspapers, and wrappers (candy and food), is another example of intaglio printing process.

[0066] In the typical flexographic printing process, a positive mirrored master of the required pattern is generally reproduced as a 3D relief on a rubber or polymer material roll or plate (printing cylinder).

[0067] The target amount of composition (C) is deposited upon the surface of the printing plate (or printing cylinder) generally using an engraved anilox roll, typically coated by an industrial ceramic whose surface contains millions of very fine dimples or cells, whose texture holds a specific amount of composition by dipping in a suitable bath of the same, excess being scraped by means of a doctor blade. The so-loaded printing cylinder finally transfers the composition onto the substrate.

[0068] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence. [0069] The invention will be now described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit in scope the invention.

[0070] Test Methods

[0071 ] Determination of oil repellence of cellulose substrates

[0072] Cellulose substrates were submitted to the so-called 'kit-test' or 'Grease Resistance Test for Paper and Paperboard' according to TAPPI Test Method T 559 cm-02 standard, the higher the rating, and the better being the oil repellence of the substrate.

[0073] FATTY ACID TEST - NFA test

[0074] Resistance of cellulose substrates against fatty acids was determined as follows. Fatty Acid solutions numbered from 1 to 1 1 (from less to most aggressive) were prepared blending different amounts of Castor oil, Oleic acid (C18: 1 ) and Octanoic acid (C8:0) and conditioned at 60°C.

Specimens of substrates were introduced in an oven maintained at 60°C and 5 drops of each test solution were dipped onto each sample. After 5 minutes at 60°C, oil drops were removed with absorbent tissue and substrates were inspected for darkening of surface.

Rating of a substrate corresponded to the highest number of the fatty acid solution that causes no alteration to the surface.

[0075] Raw Materials

[0076] In a first round of experiments, the following raw materials were used:

Table 1

Supplier Trade name PH %Solid Surface

Tension mN/m

Solvay DIOFAN ® PVDC A 050 3.0 58% 32

Solvay DIOFAN ® PVDC A 297 1 .5 60% 54

Solvay DIOFAN ® PVDC B 204 1 .5 51 % 45 Selvol Polyvinyl Alcohol 125 n/a 100% n/a

Penford Topcat ® L95 Cationic 5-9 30% n/a

Starch

[0077]

[0078] Specification of untreated substrates which were coated with the Oil and Grease repellent composition are listed in the table below:

[0079]

Table 2

[0080] ° Basic Weight of cellulosic substrate; # Water absorptiveness of paper according to Cobb test TAPPI T 441 ; * Air resistance of substrate measured according to TAPPI T 460 as time (in sec) required for 100cc of air.

[0081 ] General procedure

[0082] PVOH was cooked to 8% of solids and Topcat L95 additive was diluted to 5% of solids prior to use. The formulations of each mixture are

summarized in below table. The mixtures were stirred for 5 minutes. Using a tabletop rod coater with a rod #10 then each mixed solution was applied to the surface of the paper substrates and dried for few seconds in an oven at 1 15°C. Next, the treated sheets were tested for OGR properties, Cobb60 & WVTR. All test and drying conditions were kept the same. The viscosity of each formulation was measured by using a Brookfied viscometer at 25°C, 100 RPM, spindle LV# 3.

[0083] Detail & physical properties of formulations:

[0084]

Table 3

ID # Formulation in detail Viscosity Coated weight mPa.s g/m 2

0c 8%wt PVOH 307 13

1 c PVDC A050 at 58%wt 10 2.5

2c PVDC A297 at 60 %wt 10 2.3

3c PVDC B204 at 51 %wt 17 2.5

4c PVDC A050 (29%wt)+PVOH (4%wt) >100 >20

5c PVDC A297 (30%wt)+PVOH (4%wt) >100 >20

6c PVDC B204 (25.5%wt)+PVOH (4%wt) >100 >20

7 PVDC A050 (29%wt) + PVOH (3.8%wt) + >100 >20

Topcat L95 (0.6%wt)

8 PVDC A297 (30%wt) + PVOH (3.8%wt) + >100 >20

Topcat L95 (0.6%wt)

9 PVDC B204 (25.5%wt) + PVOH (3.8%wt) >100 >20

+ Topcat L95 (0.6%wt)

10 PVDC A050 (34.8%wt) + PVOH (0.1 %wt) 39.3 18

+ Topcat L95 (1 .1 %wt)

1 1 PVDC A297 (36%wt) + PVOH (0.1 %wt) + 38.2 16

Topcat L95 (1.1 %wt) 12 PVDC B204 (30.6%wt) + PVOH (0.1 %wt) 35.7 17

+ Topcat L95 (1 .1 %wt)

[0085] Dl: deionized water; %wt of formulations are referred to overall weight of the formulation itself.

[0086] Test results on treated substrates:

[0087]

Table 4

[0088]

Table 5

Cellulose-3 Cellulose-4

DIN

Run KIT NFA 531 16 KIT NFA

24h &

2kg

0c 13 7P 5% 4 OP

10 13 1 1 P 1 % 7 4P

1 1 13 1 1 P 0.5% 8 4P 12 13 1 1 P 0% 6 3P

[0089] Water Vapor Transmission Rate was determined on Cellulose-2 paper substrates, according to TAPPI 448- WVTR at 23.0°C and 50.0% RH; results are summarized below :

[0090]

Table 6

Good results have been obtained with a composition comprising

polyvinylidene chloride (PVDC) latex, Polyvinyl alcohol (PVOH) and polysaccharide compound in water. By using the rod coating method, high barrier films were created which that provided both hydrophobic & oleophobic properties on the surface of treated samples. The films had coating weight about 16- 18 g/m 2 with viscosity measured range from 35 to 40 mPa.s. The coating weight is directly proportional to the viscosity of the mixture. As the viscosity of the mixture increased the coat weight also increased. Maximum level of KIT test (>13) were observed when the coating weight reached >20 g/m 2 and about KIT 3-5 achieved when the coating weight was about 10g/m 2 . Depending on the substrate, at these film weights the target KIT of 7 or better was attainable. In addition to the superb oil, grease resistance, the sheets also had other desirable traits: excellent glossy, water proof property (Cobb60 less than 5 g/m 2 ), lower water vapor transmission rate and very little staining showed in the DIN 531 16 test. [0092] In a second round of experiments, a combination of tapioca and sodium alginate was used instead of cationic starch as polysaccharide compound; DIOFAN ® PVDC A736 was used as PVDC; and cellulosic substrate was unbleached base papers with BW equal to 46 g/m 2 or kraft with BW equal to 50 g/m 2 . Results are summarized in tables below. Ingredients of the formulations prepared are listed as % wt of solid component, with respect to overall weight of aqueous formulation.

[0093]

Table 7

ID Sodium Tapioca PVOH A736 Viscosity

Alginate mPa.s

13 0.4 % 0.5 % 3.2 % 9 % 87.2

14 0.4 % 0.5 % 1.6 % 9 % 76.5

15 0.4 % 0.5 % 1.2 % 9 % 54

Table 8

Run KIT NFA Gurley Cobb60 CW

Porosity g/m 2 g/m 2

sec

Bleached BW = 46 g/m 2

Untreated 0 0 792.6 42.6 0

13 9 4P >50000 21.9 3.5

14 8 3P N/A 19 1.85

15 7 2P 31489 25.2 0.92

Kraft BW = 50 g/m 2 Untreated 0 0 400 29.7 0

13 9 2P 40102 22.9 5.2

14 7 2P N/A 24.2 3.2

15 6 1 P 30852 27.3 3.0

[0095] In a third round of experiments, formulation as detailed below was applied by double size press coating method to a bleached sheet of cellulose substrate, possessing following properties:

[0096]

Table 9

[0097] The size press solution was prepared by mixing for at least 5 minutes required amounts of DIOFAN ® A736 PVDC latex (60%solids), Celvol 125 Polyvinyl Alcohol Starch (92-95% hydrolysis) cooked & diluted at 5% solids, Sodium Alginate cooked at 2% of solids and Tapioca starch used as a dry powder form, in deionized water until they were homogenously mixture. Then, using laboratory size press equipment the prepared solution was applied on provided base sheets. The sheets were then dried for few seconds on a bench top drier at 105°C. The sheets were sent again through the nip of size press solution and then dried. Details of formulation and properties of coated cellulose substrate are listed in the following tables.

[0098]

Table 10

ID # Composition of formulation Viscosity PH

% of solids wt overall weight of formulation in water mPa.s 16 0.5%Tapioca + 3.2%PVOH + 0.4%SA + 9% A736 87.2 5.5

[0099]

Table 11

[00100] * CW: coated weight.

[00101] By double size press coating method, good barrier films were created that provided both hydrophobic & oleophobic properties on the surface of treated sample.

[0102] The film had coating weight about 2 g/m 2 with viscosity around 87 mPa.s .

The results from above table 1 1 indicated that such coating weight obtained by size press treatment is effective in providing high KIT test respond, low Cobb value and low in water vapor transmission rate.

[0103] In a further set of experiments, a formulation containing DIOFAN ® A736 PVDC, PVOH, soy lecithin and tapioca was assessed. Specifically, materials used were Celvol PVOH: 8%wt solution in water; Tapioca Sunrise International, Inc.: dry powder; Red Mill-Soy lecithin at 8% wt solution in water; and DIOFAN ® A736-PVDC latex.

[0104] Press solutions contained adequate weights of PVOH, A736, lecithin, tapioca and distilled water to ultimately achieve a total solution weight of 100 g. The solutions were mixed for approximately 2 minutes at room temperature. Three types of base sheets were treated. The coating was applied using a laboratory sheet fed size press (Mathis HF-350 # 59002) operating at a nip pressure of 4.5 bar and roller speed 10m/min. First, the prepared solution was poured into the nip of the size press. Next, a sheet was passed through the size press and then dried on a bench top drier at 105°C. After drying, the sheet was allowed to cool and then passed through the size press a second time. In all, each sheet was coated twice. [0105] The composition of the press solutions used and results obtained are summarized in the following tables.

[0106]

Table 12

[0107] Percentages in Table 12 are expressed with respect to total weight of water-borne formulation.

Table 13

Gurley

ID CW* Cobb60 WVTR

KIT NFA

Porosity g/m 2 g/m 2 sec g/m 2 /day

Sheet from Mill A, base weight = 47.69 g/m 2 untreat

0 0 25 ed

17 5.84 7.5 2.0 28.03 >6,000 2.61

Sheet from Mill B, base weight = 40.54 g/m 2 untreat

0 0 62 19.72 ed

19 4.5 6.0 1 .0 29.42 446 4.87

Sheet from Mill C, base weight = 41.98 g/m 2 untreat

0 0 187 17.62 ed

20 3.76 5.5 0.5 19.93 4,624 6.93 [0108] * CW: coated weight.