EMULSION FROM THE OXIDATION PRODUCTS OF NATURAL WAXES, HAVING IMPROVED BARRIER PROPERTIES

Abstract

The invention relates to an emulsion from the oxidation products of natural waxes, having improved barrier properties, to a process of producing such an emulsion, and to cellulose fiber articles or biopolymers coated with such an emulsion from the oxidation products of natural waxes. The invention further relates to the use of such an emulsion for coating substrates that contain cellulose fibers or biopolymers.

Claims

1-18. (canceled)

19. An aqueous natural wax oxidate emulsion for forming a water and/or water vapor barrier layer on a polysaccharide or biopolymer-containing substrate, comprising (a) at least one natural wax oxidate having an acid number to OH number ratio of greater than or equal to 1; and (b) at least one anionic or nonionic emulsifier.

20. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate is preparable by an oxidation process selected from the group consisting of chromic acid oxidation, chromosulfuric acid oxidation (chromium trioxide and sulfuric acid), dichromate salt oxidation, thermal oxidation with atmospheric oxygen and electrochemical oxidation.

21. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate is selected from the group consisting of rice bran wax oxidate, corn wax oxidate, sugarcane wax oxidate, sunflower wax oxidate, and carnauba wax oxidate.

22. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate has an acid number between 1 and 140 mg KOH/g, as measured according to ISO 2114.

23. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate has a hydroxyl number, measured to DGF M-IV 6, of less than 8 mg KOH/g.

24. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate has an iodine color value, measured to DIN 6162, of less than 20.

25. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate has a dropping point between 65 and 110? C., as measured according to ISO 2176.

26. The aqueous natural wax oxidate emulsion according to claim 19, wherein the natural wax oxidate is present in the emulsion to an extent of 5% to 50% by weight, based on the total mass of the emulsion.

27. The aqueous natural wax oxidate emulsion according to claim 19, wherein the nonionic emulsifier has an HLB value between 11 and 19.

28. The aqueous natural wax oxidate emulsion according to claim 19, wherein the at least one nonionic emulsifier is selected from the group consisting of fatty alcohol polyglycol ether, alcohol ethoxylate, and tributylphenol ethoxylate.

29. The aqueous natural wax oxidate emulsion according to claim 19, wherein the emulsifier is an anionic emulsifier system.

30. The aqueous natural wax oxidate emulsion according to claim 19, wherein the emulsifier is present in the emulsion to an extent of 1-20% by weight, based on the total mass of the emulsion.

31. A process for producing an aqueous natural wax oxidate emulsion according to claim 19, comprising the steps of a) providing a natural wax oxidate and an anionic or nonionic emulsifier; b) emulsifying the natural wax oxidate with the aid of the emulsifier in water at a temperature above the melting point of the natural wax oxidate, wherein the natural wax oxidate has an acid number to OH number ratio of greater than or equal to 1.

32. The process for producing an aqueous natural wax oxidate emulsion according to claim 31, wherein the natural wax oxidate is producible by an oxidation method selected from the group consisting of chromic acid oxidation, chromosulfuric acid oxidation (chromium trioxide and sulfuric acid), dichromate salt oxidation, oxidation with atmospheric oxygen and electrochemical oxidation.

33. A polysaccharide- or biopolymer-containing substrate comprising a water vapor barrier layer formed from the aqueous natural wax oxidate emulsion according to claim 19.

34. The polysaccharide- or biopolymer-containing substrate according to claim 33, wherein the polysaccharide- or biopolymer-containing substrate is a cellulosic substrate.

35. A process for producing a polysaccharide- or biopolymer-containing substrate, comprising the steps of a) applying the aqueous natural wax oxidate emulsion according to claim 19 to the surface of the polysaccharide- or biopolymer-containing substrate b) drying the coated substrate to form the barrier layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0022] Production of the natural wax oxidate in the natural wax oxidate-containing emulsion can be accomplished, for example, by employing any of the known oxidation methods that also oxidize the natural wax itself and hence increase the acid number of the natural wax oxidate, measured to ISO 3681, by at least 5 mg KOH/g, preferably at least 10 mg KOH/g, by comparison with the starting material (generally the natural wax or a bleached form of the natural wax) and do not just lead to bleaching of the wax by oxidation of the impurities in the wax. These include oxidation with chromic acid, with chromosulfuric acid (chromium trioxide and sulfuric acid) and with dichromate salts, thermal oxidation with oxygen, which can also be carried out with the aid of a catalyst, and all kinds of electrochemical oxidation.

[0023] Suitable natural wax oxidates are especially those that are produced by oxidation from genuine natural waxes. Genuine natural waxes are understood to mean those natural waxes that are already in wax form in the raw material source and need not be subjected to further chemical conversion to be regarded as a wax.

[0024] Preference is given to natural waxes that are formed from monovalent esters of long-chain fatty acids.

[0025] Particular preference is given to oxidates of rice bran wax, of corn wax, of sugarcane wax, of sunflower wax and of carnauba wax. Particular preference is given to oxidates of rice bran wax and corn wax. Very particular preference is given to rice bran wax oxidate.

[0026] The natural wax oxidates preferably have an acid number, measured to ISO 2114, between 1 and 140 mg KOH/g, preferably between 15 and 140 mg KOH/g, more preferably between 30 and 140 mg KOH/g. Very particular preference is given to acid numbers between 15 and 110 mg KOH/g or between 30 and 110 mg KOH/g. These acid number ranges are achieved by the oxidation alone and do not require a further esterification step. Such natural wax oxidates on the one hand have sufficient polarity to be more easily emulsifiable in water, but on the other hand are not yet so polar that the barrier layer has defects attributable to polarity in the microstructure of the barrier layer that adversely affect the barrier effect.

[0027] In a preferred embodiment, the at least one natural wax oxidate in the emulsion of the invention has a saponification value between 30 and 200 mg KOH/g, preferably between 50 and 180 mg KOH/g, more preferably between 80 and 170 mg KOH/g, measured to ISO 3681. Very particular preference is given to saponification values between 80 and 140 mg KOH/g.

[0028] The at least one natural wax oxidate in the emulsion of the invention preferably has a hydroxyl number, measured to DGF M-IV 6, of less than 8 mg KOH/g, preferably less than 5 mg KOH/g, which represents more homogeneous material properties and hence leads to formation of a more homogeneous barrier layer with fewer defects in the microstructure.

[0029] In a preferred embodiment, the natural wax oxidate has an iodine color number of less than 20, preferably less than 15 and more preferably less than 10, measured to DIN 6162. A low iodine color number indicates a particularly light color of the wax, and the wax thus does not have an adverse effect on the color of the substrate.

[0030] The at least one natural wax oxidate in the emulsion of the invention preferably has a dropping point between 65 and 110? C., measured to ISO 2176. This means that the resulting coating has good thermal stability without having to expend too much energy in the production of the natural wax emulsion in order to cause the natural wax to melt.

[0031] In order to assure easy applicability of the aqueous natural wax emulsion and to make the barrier layer as thin and homogeneous as possible, the natural wax oxidate is present in the emulsion to an extent of 5% to 50% by weight, preferably to an extent of 10% to 45% by weight, more preferably to an extent of 15% to 40% by weight, most preferably to an extent of 20% to 35% by weight, based on the total mass of the emulsion.

[0032] In a preferred embodiment, the at least one emulsifier is an anionic or nonionic emulsifier. Hydrophobic waxes can be emulsified particularly easily with the aid of anionic or nonionic emulsifiers.

[0033] Anionic emulsifiers have an ammoniacal odor that might cause the user to feel unwell. This can be avoided when nonionic emulsifiers are used, preferably surfactants. In addition, anionic emulsifiers have a relatively high pH, which has an unfavorable effect in some applications. Thus, nonionic emulsifiers are preferred for some applications, for example pH-sensitive products or cosmetic products.

[0034] The nature of the nonionic emulsifier can be described by the mass ratio between the polar and the nonpolar portion of a surfactant and is defined via the HLB value (hydrophilic-lipophilic balance, the hydrophilic-lipophilic ratio of the molecule). The level of this hydrophilic-lipophilic ratio can be determined by calculation of values for the different regions of the molecule, as described by Griffin (cf., for example, Journal of the

[0035] Society of Cosmetic Chemists, 5 (4), 249-256 (1954)). The Griffin method was developed primarily for nonionic surfactants; the HLB value is calculated by the following formula:

[00001]$\mathrm{HLB}=10*\mathrm{Mh}/M$

where Mh is the molecular mass of the hydrophilic part of the molecule and M is the molecular mass of the overall molecule, which results in a value on a scale from 0 to 20.

[0036] An HLB value of 0 corresponds to a completely lipophilic molecule; an HLB value of 20 corresponds to a completely hydrophilic molecule.

[0037] Surfactants having a low HLB value have good fat-dissolving properties; a high HLB value results in good wetting of hydrophilic surfaces. On the basis of different HLB values, it is possible to form stable emulsions in O/W to W/O systems.

[0038] An oil-in-water emulsifier (O/W emulsifier) is understood to mean an emulsifier having an

[0039] HLB value high enough to give oil-in-water emulsions. The HLB value of such an emulsifier is normally greater than about 8 and is frequently in the range from 8 to 18.

[0040] The nonionic emulsifier that stabilizes the natural wax oxidate-in-water emulsion of the invention preferably has an HLB value between 11 and 19, since it is possible to particularly efficiently stabilize a natural wax oxidate emulsion with such a nonionic emulsifier. The HLB value is more preferably between 13 and 18.

[0041] The nonionic emulsifier preferably has an EO value (number of ethylene oxide units bonded to the functional group) of greater than 10-80.

[0042] The nonionic emulsifiers are preferably fatty alcohol polyglycol ether, alcohol ethoxylate, for example fatty alcohol ethoxylate, and tributylphenol ethoxylate.

[0043] In an alternative embodiment, the emulsifier that stabilizes the aqueous natural wax oxidate emulsion is an anionic emulsifier system since such systems surprisingly achieved very good results in the stabilization of the emulsion and the formation, flexibility and stability of the barrier layer, and the barrier layers have very good water stability and water vapor barrier action. This means that these emulsifiers are especially suitable for applications in which high water stability is required, for example in woodcare products.

[0044] The anion of an anionic emulsifier system can be obtained by adding a water-soluble or water-dispersible alkali metal hydroxide and/or basic ammonium compound to an organic acid having a straight-chain aliphatic hydrocarbyl radical having 12 to 24 carbon atoms. The anion is supplied as an alkali metal salt, preferably a sodium and/or potassium salt, or a corresponding ammonium or substituted ammonium salt of the corresponding organic acid.

[0045] The term ammonium salt refers to those neutralization products that are obtained by reaction of surfactant acids in an aqueous medium with ammonia or amines such as volatile bases, e.g. morpholine, methylaminopropanol, diethylaminoethanol (DEAE) etc., or nonvolatile bases, e.g. monoethanolamine, triethanolamine, isopropanolamine, ?,?- and ?,?-substituted diamines such as ethylenediamine, propylene-1,2-diamine, propylene-1,3-diamine, butylene-1,4-diamine etc. DEAE, owing to its basic characteristics, may form a corresponding salt with an organic acid.

[0046] The polar organic group of the salt or acid may be the carboxylate, sulfate or sulfonate ion, and the anion-providing compound may have more than one such polar group.

[0047] Examples of suitable organic acids that provide the anion are natural and synthetic aliphatic carboxylic acids having 12 to 24 carbon atoms, e.g. myristic acid, palmitic acid, stearic acid, oleic acid and behenic acid, especially those of the soaps as obtained by cleavage of triglyceride oils, for example tallow fatty acid, which is a mixture of fatty acids consisting mainly of palmitic, stearic and oleic acid.

[0048] The anion is preferably one in which there is an alkyl or alkenyl group having 16 to 24 carbon atoms.

[0049] Preference is given to using the oleic acid/ammonium hydroxide/KOH emulsifier system.

[0050] The amount of the emulsifier used has an effect on the stability of the suspension and the distribution and size of the wax particles. It has been found that particularly thin and homogeneous barrier layers can be formed when the emulsifier is present in the emulsion to an extent of 1-20% by weight, preferably to an extent of 2-15% by weight, based on the total mass of the emulsion.

[0051] The invention further provides a process for producing an aqueous natural wax oxidate emulsion, comprising the steps of: [0052] a) providing a natural wax oxidate and an anionic or nonionic emulsifier [0053] b) emulsifying the natural wax oxidate with the aid of the emulsifier in water at a temperature above the melting point of the natural wax oxidate,
characterized in that the natural wax oxidate has a ratio of acid number to OH number of not less than 1. The natural wax oxidate is producible by the oxidation method described above.

[0054] The invention further provides for the use of an aqueous natural wax oxidate emulsion of the invention for coating of a polysaccharide- or biopolymer-containing substrate, preferably a cellulosic substrate with a water vapor barrier layer. Additionally suitable are water vapor barrier layers for water-permeable polymer substrates, for example biopolymer substrates, especially substrates composed of polylactide (PLA).

[0055] Accordingly, the invention further provides a polysaccharide- or biopolymer-containing substrate comprising a water vapor barrier layer which is manufactured from an aqueous natural wax oxidate emulsion of the invention.

[0056] The polysaccharide- or biopolymer-containing substrate is preferably a cellulosic substrate, more preferably paper or cardboard.

[0057] These coated polysaccharide- or biopolymer-containing substrates can be used for any kind of packaging or shell, for example tobacco articles, outer packaging for tobacco articles, paper cups, packaging for frozen articles, outer packaging for bread, sausage and cheese and plants, and cardboard boxes, outer packaging for electronic articles etc.

[0058] The invention further provides a process for producing a polysaccharide - or biopolymer-containing substrate, comprising the steps of: [0059] a) applying an aqueous natural wax oxidate emulsion of the invention to the surface of the polysaccharide- or biopolymer-containing substrate; [0060] b) drying the coated substrate to form the barrier layer.

EXPERIMENTAL PART

[0061]

TABLE-US-00001 TABLE 1 Methods of determining the parameters reported Parameter Method Density [g/cm.sup.3] ISO 1183-3 Acid value (AV) ISO 2114 [mg KOH/g] Saponification value (SV) ISO 3681 [mg KOH/g] Dropping point (DP) [? C.] ISO 2176 Needle penetration value DIN 51579 (NPV) [mm.sup.-1] Hydroxyl number (OH DGF M-IV 6 number) [mg KOH/g] lodine color value (ICV) DIN 6162 (2014) Thermogravimetric DIN 51006 analysis (TGA) [% by wt.] Heating from 25 to 300? C. at 5 K/min, then constant temperature of 300? C. for 30 min. Measurement of loss of mass on attainment of 300? C. and after 30 min at 300? C. Cobb value DIN EN ISO 535 Renewable The Renewable Carbon Index (RCI) describes the proportion of Carbon Index carbon atoms from renewable raw materials in an organic compound or mixture and is calculated by the following formula: [00002]$\mathrm{RCI}\left(\%\right)=\frac{{.Math.}_{i=1}^N\left(M_{\mathrm{total}}*M_i*{\mathrm{BCC}}_i*12/{\mathrm{MW}}_i\right)}{{.Math.}_{i=1}^N\left(M_{\mathrm{total}}*M_i*{\mathrm{BCC}}_i*12/{\mathrm{MW}}_i\right)+{.Math.}_{i=1}^N(M_{\mathrm{total}}*M_i*{\mathrm{FCC}}_i*}$ -M.sub.total = total mass of the micronized wax additive -M.sub.i = mass of the ith component of the micronized wax additive (in %) -BCC.sub.i = number of biobased carbon atoms in the ith component of the micronized wax additive -FCC.sub.i = number of fossil carbon atoms in the ith component of the micronized wax additive -MW.sub.i = molar mass of the ith component of the micronized wax additive Inorganic components and water are not taken into account in the calculation of the RCI. HLB value The Griffin HLB value (hydrophilic-lipophilic balance) indicates the mass ratio between the polar and nonpolar portion of a surfactant. The Griffin method (1954) was developed primarily for nonionic surfactants, where the HLB value is calculated as follows: HLB = 10 * Mh/M where Mh is the molecular mass of the hydrophilic part of the molecule and M is the molecular mass of the overall molecule, which gives a result on a scale from 0 to 20.

DESIGN OF THE EXAMPLES

[0062]

TABLE-US-00002 TABLE 2 Waxes and wax oxidates used Wax OH type Manufacturer Density AV number SV DP NPV ICV RCI TGA Crude rice Natural Yihai Kerry 0.98 4 8.7 81 78? C. 4 >120 100 n.d. bran wax wax, rice Arawana bran wax Holdings Co. Ltd. PODAX- Refined Shanghai Tongs 0.98 12.6 19 88 78.9 4 37 n.d. n.d. BN 5 rice bran Science & wax Technology Co. Ltd. Licocare Rice bran Clariant Ltd. 0.98 19 5 89 78 1 12 100 7.44/ RBW 101 wax oxidate 18.35 Licocare Rice bran Clariant Ltd. 0.99 52 4 113 77 3 3 100 15.49/ RBW 102 wax oxidate 32.03 Licocare Rice bran Clariant Ltd. 1.00 128 5 168 76 3 1 100 RBW 106 wax oxidate Licowax Oxidized Clariant Ltd. 0.95 17 104 4 0 5.1/ PED 521 polyethylene 8.3 Corn wax Oxidized Clariant Ltd. 0.98 45 11 104 76 2 1 100 17.6/ oxidate 1 corn wax 41.3 Corn wax Oxidized Clariant Ltd. 1.00 65 2 123 73 3 0.7 100 29.4/ oxidate 2 corn wax 55.7 Corn wax Oxidized Clariant Ltd. 0.99 127 1 156 71 3 0.3 100 65.6/ oxidate 3 corn wax

Production of Corn Wax Oxidates 1 to 3

[0063] Since the corn wax oxidates are not commercially available products, the experimental conditions for production of the corn wax oxidates are detailed hereinafter:

[0064] A 3 l reaction vessel equipped with stirrer, temperature sensor, dropping funnel and reflux condenser was initially charged with the amount of chromium trioxide in sulfuric acid (concentration: 100 g CrO3/l) specified in table 4, and heated to 100? C. Molten (90? C.) natural wax in the raw state was then added a little at a time. The temperature of the reaction mixture was adjusted to 110? C., and the reaction mixture stirred with a precision glass stirrer at approx. 200 rpm for 4 h. The heating and stirring were switched off. As soon as the phases had separated, the aqueous phase was separated off. This operation was conducted twice for production of corn wax oxidates 1 and 2, and five times for production of corn wax oxidate 3, using the amounts specified in table 3.

TABLE-US-00003 TABLE 3 Statements of amount for production of the corn wax oxidates used Example 1 2 3 Natural wax [g] 200 200 200 CrO.sub.3/H.sub.2SO.sub.4 [l] 2.0 2.0 1.0 2.0 3.4 1.0 1.0 1.0 1.0

[0065] The organic phase was freed of chromium residues by washing with an aqueous solution of oxalic acid and sulfuric acid and then by washing with water, drained into warm centrifuge tubes, and centrifuged.

TABLE-US-00004 TABLE 4 Emulsifiers used for production of the emulsions Emulsifier Chemical HLB Emulsifier No. classification Generic description INCI value type E 1 fatty alcohol tallow alkyl ethoxylate Ceteareth-20 15.4 nonionic polyglycol ether with 20 EO surfactant E 2 fatty alcohol oleyl ethoxylate with Oleth-10 12.6 nonionic polyglycol ether 10 EO surfactant E 3 tributylphenol tri-sec-butylphenol Dodoxynol-50 17.9 nonionic ethoxylate ethoxylate with 50 EO surfactant E 5 fatty alcohol C12/C15-oxo alcohol C12-15 13.5 nonionic polyglycol ether ethoxylate with 10 EO Alketh-10 surfactant E 6 fatty alcohol tallow alkyl ethoxylate Ceteareth-20 16.2 nonionic ethoxylate with 25 EO surfactant E 7 fatty acid-based oleic acid n.a. n.a. anionic emulsifier ammonium hydroxide emulsifier system (30%)/KOH E 8 diethylethanolamine n.a. n.a. anionic (DEAE) emulsifier

A) Production of Various Water-Based Wax Emulsions

A1) Production of Formulations F1, F2, F9, F10 From Table 5 and formulations F12, F13, F14, F15 From Table 6:

[0066] The respective wax and the respective emulsifier were fully melted at 125? C. and stirred to give a homogeneous mass. Boiling distilled water was stirred into the wax melt at 125? C. The resultant emulsion was cooled down while stirring vigorously (about 3 K/min).

A2) Production of Formulation F4 From Table 5:

[0067] The wax was fully melted at 125? C., and the DEAE was slowly added dropwise. The melt was stirred for 2 min. The boiling water was stirred into the wax melt at 125? C. The resultant emulsion was cooled down while stirring vigorously (about 3 K/min).

A3) Production of Formulations F3, F5 and F6 From Table 5 and Formulations F16 and F17 From Table 6:

[0068] The wax, oleic acid, ammonia solution and KOH were blended with 50% of the required amount of distilled water in a pressure reactor. The blend was heated to 135? C. in the pressure reactor, and the remaining amount of water was added to the mixture at about 125? C. The mixture was stirred at 135? C. for 15 min. The emulsion was then cooled down to 30? C. while stirring (about 3 K/min).

A4) Production of Formulation F7:

[0069] The wax and emulsifier E 5 were fully melted at 125? C. and stirred to give a homogeneous mass. The KOH/ethylene glycol mixture was added dropwise while stirring and blended for a further 2 min. The hot wax mixture was then stirred into boiling distilled water. The resultant emulsion was cooled down while stirring vigorously (about 3 K/min).

TABLE-US-00005 TABLE 5 Formulations used based on rice bran wax oxidates Formulation F1 F2 F3 F4 F5 F6 F7 F9 F10 (I) (I) (I) (I) (I) (I) (C) (C) (C) PODAX 10 20 BN-5 Licocare 20 RBW 101 Licocare 25 20 20 RBW 102 Licocare 25 20 RBW 106 Licowax 20 PED 521 Oleic acid 4.0 4 7 Ammonium 8.0 8.0 6.5 hydroxide KOH (20%) 0.2 0.2 0.5 KOH 21.5% 1.6 in ethylene glycol E 1 5 E 2 2.85 5.6 E 3 5 E 5 4.0 E 8 5.5 Dist. water Make up to 100% with dist. H.sub.2O Emulsion + + + + + + + + ? stability

TABLE-US-00006 TABLE 6 Formulations used based on corn wax oxidates F12 F13 F14 F15 F16 F17 (I) (I) (I) (I) (I) (I) Corn wax oxidate 1 25 20 Corn wax oxidate 2 25 25 20 Corn wax oxidate 3 25 Oleic acid 4 4 Ammonium hydroxide 8 8 KOH (20%) 0.2 0.2 E 1 5 5 E 2 E 3 5 E 6 5 Dist. water Make up to 100% with dist. H.sub.2O Emulsion stability + + + + + +

[0070] The inventive formulations F1-F6 and F12-F17 listed in tables 5 and 6 all form stable emulsions. This is not true of comparative example F10, where no stable emulsion is formed any longer at a wax content of 20%. Comparative example F9 with 10% wax does form a stable emulsion, but the lower wax content is disadvantageous for coating quality and drying time.

B) Production of Coated Paper Substrates With a Wax Emulsion

[0071] The wax emulsion detailed in table 7 was applied with a 50 ?m coating bar and a test area of 12.5 cm?12.5 cm was cut out and stored at constant temperature of 23% and 30% relative humidity for 24 h. The sample was tared (Tara 1) and clamped in the Cobb aluminum cup.

[0072] Then 100 ml of distilled water was added to the sample for 60 s and removed. The residues of water were removed with blotting paper and an absorptive roller, and the weight was determined again (Tara 2). The Cobb value was calculated by the following formula:

[00003]$\mathrm{Cobb}{\mathrm{value}}_{60s}=\left(\mathrm{Tara}3-\mathrm{Tara}2\right)?115.48658$

[0073] The values were determined in triplicate, and the median of the measurements is listed in table 7.

TABLE-US-00007 TABLE 7 Cobb.sub.60 values of the coated paper substrates Cobb.sub.60 value Algro Finess Cobb.sub.60 value 80 g/m.sup.2 Koehler Uncoated 30.41 35.80 F1 13.85 20.78 F2 13.47 23.86 F3 6.54 5.77 F4 0 0 F5 0 0 F6 2.31 5.00 F7 73.1 172.8 F9 61.59 139.35 F12 0.00 0.38 F13 6.54 ?0.38 F14 15.78 3.46 F15 15.01 15.4 F16 1.54 0.77 F17 ?1.15 0.77

[0074] All inventive examples F1-F6 and F12-F17, by comparison with the uncoated paper and comparative examples F7 and F9, show a significant reduction in water absorption, manifested in lower Cobbso values.

C) Production of Coated Carrier Films for Determination of the Barrier Effect of a Wax Coating With the Aid of the Water Vapor Transmission Rate

[0075] The wax or wax oxidate emulsion or dispersion was coated onto cellophane as a thin film. For this purpose, a semiautomated Sumet Messtechnik CUF 5 coating system was used for processing of substrates in sheet form with a maximum area in DIN A3 format (420?297 mm). The wet application was 50 ?m. The application rate was 30 mm/s. The drying temperature was between 70? C. and 90? C. for a drying time of 1-5 min.

[0076] In order to eliminate the effects of the substrate, all barrier layers were applied to cellophane, which has a known water vapor permeability. The water vapor transmission rate Q of cellophane film is 1084 g/(m.sup.2*d).

[0077] The water vapor barrier was determined as water vapor transmission rate Q according to DIN 53122-1 at 23? C. and a moisture gradient of 85% relative humidity on one side of the barrier and 0% on the other side of the barrier. The measured Q value (unit: g/(m2*d)) describes how many grams of water would permeate through an area of one square meter in one day. However, this value depends crucially on the thickness of the wax layer. The thicker the wax layer, the lower the value measured. In order to make various materials of different thickness comparable, therefore, a value normalized to layer thickness 100 ?m (Q100 [g*100 ?m/(m2*d)]) is reported. This is ascertained by the following formula:

[00004]$\frac{1}{Q\left(\mathrm{overall}\right)}=\frac{1}{Q\left(\mathrm{substrate}\right)}+\frac{1}{Q\left(\mathrm{barrier}\mathrm{layer}\right)}$

[0078] In this way, it is possible to calculate the water vapor transmission rates of the respective barrier layer of the measurements listed in table 8 by

[00005]$\frac{1}{Q\left(\mathrm{barrier}\mathrm{layer}\right)}=\frac{1}{Q\left(\mathrm{overall}\right)}+\frac{1}{1084g/\left(m^2*d\right)}.$

[0079] In order to ascertain the water vapor permeability Q100 normalized to layer thickness, the layer thickness of the barrier layer was determined with a microscope with the aid of a microtome section of the coated substrate.

[00006]$Q100=\frac{Q\left(\mathrm{barrier}\mathrm{layer}\right)}{100}*\mathrm{barrier}\mathrm{layer}\mathrm{thickness}$

[0080] The reference used is the water vapor transmission rate of Lupolen, the Q100 value of which is 1.

[0081] In addition, the water vapor permeability of a thin Crude RBW layer not applied to a cellophane substrate was determined.

[0082] The measurements reported in table 8 are an average from 4 measurements performed.

TABLE-US-00008 TABLE 8 Water vapor transmission rates of uncoated and coated film substrates (carrier films) Q(overall) Q100 of Type of (substrate + Q Barrier layer the sample emulsion/ barrier layer) (barrier layer) thickness [g*100 ?m/ Sample coating [g/(m.sup.2*d)] [g/(m.sup.2*d)] [?m] (m.sup.2*d)] Cellophane no coating no wax 0 uncoated Lupolen no coating, 100 1.00 1800 H no cellophane substrate Crude rice substrate-free 0.202 0.2020 239 0.48 bran wax barrier layer F1 (I) nonionic 28.2 ? 2.4 28.9 6.6 1.9 F2 (I) nonionic 45.3 ? 2.7 47.3 5.5 2.6 F4 (I) anionic 7.36 ? 0.4 7.4 4.4 0.32 F5 (I) anionic 6.86 ? 1.1 6.9 3.3 0.23 F6 (I) anionic 20.0 ? 4.0 20.4 5.5 1.1

[0083] All inventive examples show a significant improvement in water vapor permeability over the uncoated cellophane film, which is manifested in lower Q100 values. The Q100 values of the inventive examples are within a comparable range to the Q100 values of the Lupolen 100 reference film, which represents a standard polyethylene-based barrier material.

[0084] Crude rice bran wax does show good barrier properties, but is not emulsifiable. Application from the melt requires a higher energy input and is associated with a higher layer thickness compared to aqueous emulsions, which has an adverse effect on material consumption. Higher layer thicknesses additionally have an adverse effect on adhesion and flexibility of the barrier layer.