US3087835A

US3087835A - Lacquers for wood finishing with improved filling power

Info

Publication number: US3087835A
Application number: US862046A
Authority: US
Inventors: Auer Laszlo
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-12-28
Filing date: 1959-12-28
Publication date: 1963-04-30
Anticipated expiration: 1980-04-30

Description

United States Patent O 3,087,835 LACQUERS FOR WOOD FINISHING WITH IMPROVED FILLING POWER Laszld Ar'rer, 27 Lakeview Road, New Rochelle, N.Y. N Drawing. Filed Dec. 28, 1959, Ser. No. 862,046

r 18 Claims. (Cl. 117--73) GENERAL OUTLINE OF INVENTION into the wood when they are applied, e.g. by spraying.

As an illustration of wooden surfaces furniture can be taken. Some years ago in finishing high grade furniture as many as 6 to 8 coats of lacquer were applied. In most cases the surface was rubbed after each coat, before the next coat was applied. This procedure was expensive, when we consider the cost of labor applying each coat and sanding the surface further the cost of the lacquer consumed and the cost and size of the space taken up during the drying and finishing operation.

In order to reduce cost, the art has utilized many avenues of approach. Resins were developed which perrnitted to increase the N.V. content of the lacquers without increase in lacquer viscosity and without detriment to film properties. So called high solids lacquers were formulated, which are applied at elevated temperatures in order to obtain spraying viscosity by the combined action of thinners and elevated temperatures. This invention represents a novel approach to increase the filling power of wood finishing lacquers which can be applied both to the older type conventional wood finishing lacquers or to the more recent high resin or high solids lacquers with equal success.

According to this invention Water is incorporated into the wood finishing lacquer by forming a water-in-oil type emulsion. The presence of the water in emulsified form at the time of application increases the filling power of the lacquer. When two lacquers are prepared, which have the same viscosity at the time of spraying, the same N.V. content and the same identical film former ingredients, the one which contains emulsified water: will have as much as 50% to 100% increased filling power. This means that the water containing lacquer will require e.g. 3 or 4 coats to appear equal to 6 coats of the comparative water-free lacquer.

The 6 coat example for the conventional comparative lacquer is taken for ease of illustration and without implying that the majority of todays lacquers require 6 coats for the desired eifect. It should also be mentioned, that whereas in such comparisons it is easy and advisable to use equal viscosities for spraying and it is also easy to secure equal film former formulation (nonvolatile content composition), in many cases equal N.V. percentage in the two comparative lacquers may be difficult to achieve, because of the viscosity increasing action of the emulsified water. In such cases the comparison can be made by applying equal film former weight units distributed over a surface area unit, instead of counting numbers of coats applied.

Emulsified Water usually increases viscosity. This may have to be counteracted by additional thinner addition, thereby reducing the N.V. content of the lacquer at the time of application by e.g. spraying. A higher N.V. content in itself is desirable for filling power. The aim of this invention is not to form and use water-in-oil emulsions per se, but to utilize the increased filling power eifect of the emulsified water. Therefore, for the purposes of this invention it is of advantage to keep the Water content of the emulsion as low as possible, while still obtaining the improvement in filling action. The water content may vary depending on formulation and nature of the lacquer composition. The water content of the lacquer emulsion is usually at least about 5% and not more than about 50% at spraying viscosity. In most cases the water content at spraying viscosity, is not more than about 20% to about 30%.

There are basically 3 methods to prepare the lacquer compositions containing the emulsified water at the spraying step:

Method A.--A lacquer is prepared first, which at the time of shipment to the consumer (finisher) contains all the required water in emulsified form. The finisher adds thinner, which is free of emulsified water, before application starts. As an alternative of this method, the finished lacquer, already thinned to spraying viscosity, is shipped to the user.

M ethoa B.--A substantially water-free lacquer is shipped to the finisher and he incorporates the water, to form the emulsion and also the thinner to obtain spraying viscosity before he applies the composition. In subalternatives of thiE method the emulsifying agents may be incorporated into the lacquer, making it a self-emulsifying lacquer, or into the water, before incorporating it into the lacquer.

Method C.-A substantially water-free lacquer is shipped to the user and he adds thereto a thinner containing the water emulsified therein. In this method the thinner, containing the emulsified water, will simultaneously cause the increase in filling power and the thinning action required to obtain spraying viscosity.

Additional methods may be created by combining in various alternatives the Methods A to C. For instance, emulsified water could be present bothin the lacquer, as shipped, and in the thinner used for reduction of viscosity; or water could be additionally added to a lacquer already containing emulsified'water at the time the thinner is added; or water and thinner which contains emulsified water could be added simultaneously to a lacquer which itself may contain or be free of emulsified water.

For the sake of simplicity of presentation and without limiting the scope of the invention, the illustrations will be made on Method A, as outlined above.

SELECTION OF RAW MATERIALS (1) Solvents-Solvents which are miscible with water reduce emulsion stability. I prefer to use solvents which are substantially water-immiscible. For the purposes of this invention a solvent is considered substantially waterimmiscible if at room temperature the solvent does not form with water solutions having higher than about 10% or 20% solvent content and if the solvent at room temperature does not dissolve substantially more than about 20% water.

Examples of water-miscible solvents are elg. methyl alcohol, ethyl alcohol, propyl and isopropyl alcohol, Cellosolve, methyl Cellosolve, methy acetate, methy Cellosolve acetate, acetone, amongst others. Solvents falling into this group are not preferred, but may be present occasionally in small quantities, where they 'do not disturb as yet emulsion stability. Some may be even added in small quantities to achieve specialty effects, like the Cellosolves, which may be incorporated in small percentages into thinners, which are added to the emulsions shortly before application, to reduce their viscosity. Such small additions may accelerate demulsification, after spraying.

The preferred solvents for this invention are the substantially water-immiscible solvents, as defined above. Examples are:

Alcohols: Butanol, Isobutanol, 2-methyl-l-butanol, 1- .pentanol, primary amyl alcohol, Z-methyl-l-pentanol, methyl-amyl alcohol (4-methyl-2-pentanol), 2-ethylbutanol, l-hexanol, iso-hexanol, 2-2 dimethyl-l-butanol, 2-ethyl hexanol, 2-2-4 trimethyl-l-pentanol, diisobutyl carbinol (2-6 dimethyl-4-heptanol), 2-propyl-l-heptanol, methyl-isobutyl :carbinol, secondary butyl alcohol, secondary amyl alcohol, etc.

Esters: Ethyl cformate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, secondary butyl acetate, isobutyl acetate, ethyl-4-formyl butyrate, primary amyl acetate, fusel oil, methyl-amyl acetate, 2-ethyl-hexyl acetate, butyl Cellosolve acetate, butyl C'arbitol, methylvinyl acetate, etc. Cellosolve acetate, which has in water 22.9% solubility, can still be utilized in small quantities.

Ethers: Ethyl ether, isopropyl ether, butyl ether, hexyl ether, dibutyl Cellosolve, dibutyl Carbitol, etc.

Ketones: Diethyl ketone, methyl-ethyl ketone (MFK), methylpropyl ketone, methyl-isobutyl ketone (MIBK), methyl-n-amyl ketone, methyl-isoamyl ketone, ethylbutyl ketone (EBK), diisobutyl ketone (DIBK), mesityl oxide, isophorone, acetyl acetone (2,4 pentane dione), isobutyl-heptyl ketone (2,6,8-trimethyl-4-nonanone), ethyl-amyl ketone (EAK), methyl-n-butyl ketone, cyclohexanone, etc. Acetyl-acetone dissolves in water 16.6%, but in small quantities it still can be used.

Hydrocarbons: Hydrocarbons used in the paint industry are all substantially water-immiscible. Examples are:

Petroleum solvents: Boiling range F.

Low boiling naphthas 100 to 200 Lacquer diluent naphthas 200 to 250 V.M. & P. Naphtha (Varnish Makers and Painters Naphtha) 246 to 297 Mineral spirits 312 to 389 Aromatic solvents:

Benzene (benzol) 174 to 178 Toluene (toluol) 230 to 233 Xylene (xylol) 279 to 284 Hi-fl-ash naphtha 302 to 379 Various hydrogenated petroleum naphth-asvarying, for various grades.

Chlorinated solvents: Ethylene dichloride is an example for a suitable chlorinated solvent for emulsion work.

(2) Primary lacquer film frmers.-The most important lacquer film former for the purposes of this invention is nitrocellulose. However, ethylcellulose can also be used as the primary film former or it could be used in combination with nitrocellulose. Chlorinated rubber, such as Parlon, is also a film former, which can be present in wood finishing lacquers.

Nitrocellulose is marketed in the United States wetted with an alcohol. The normal grades contain 65% nitrocellulose and 35% wetting alcohol. The wetting alcohol can be ethyl alcohol or butyl alcohol (butanol). In

view of the water-miscible nature of ethyl alcohol, for the purposes of this invention butyl alcohol Wetted nitrocellulose is preferred. Nitrocellulose is made in RS- grade, which is ester soluble and in SS-grade, which is alcohol soluble. 'For furniture lacquers the RS-grade is preferred by the trade and therefore illustrations will be made on RS-grade exclusively, except where SS-grade is specifically mentioned. The viscosity grades of nitrocellulose are described in the literature. The illustrations will use grades from A second type to the 60-80 seconds type. These viscosity designations are those established by the Hercules Powder Company method. Abroad nitrocellulose is also marketed in chip form, which is free of volatile solvents. The chips consist of nitrocellulose and 20% tricresyl phosphate.

Ethylcellulose is obtainable in various viscosity grades and in various degrees of ethoxylation. The degree of ethoxylation is expressed by letters, such as T-type, N- type, G-type, etc.

(3) Resins-Resins and resin solutions used in the formulation of furniture lacquers are not water-miscible and their selection therefore leaves great latitude of freedom. The great majority of resins used for the purpose of lacquer formulations, are useful in the instant invention. Examples are: Estergum, pentaerythritol esters of rosin, modified rosin pentaerythritol esters, rosin modified maleic esters of glycerin or pentaerythritol, oilmodified alkyd resins of the drying, semi-drying and,

non-drying type, epoxy resin esters, hydrocarbon resins, urea-formaldehyde and melamine-formaldehyde resins, pure phenolic resins, compatible acrylic resins, amongst others.

Examples of commercially available resins, arranged according to manufacturers, are:

Aroplaz 905, Aroplaz 1130, Aroplaz 1273, Aroplaz 2570.

Beetle 216, Beetle 227-8, Melmac 245-8 (Cymel 245-8), Rezyl 99, Rezyl 99-5, Rezyl 387-5, Rezyl X-315, Teglac 763, Teglac Z-152, Rezyl 807-1.

Beckosol 7, Beckosol 70, Beckosol 1303, Beckosol 1307, Beckosol 1308.

Bakelite XR-3180, Bakelite XJ-431.

Glyptal 1247, Glyptal 2477, Glyptal 2471.

Syntex H-3.

Synthetics H82-60x, Cellolyn -80T, Cellolyn 502, Lewisol 2L, Lewisol 33, Neolyn 23, Staybelite Ester 10, Pentalyn 802A, Petrex 7-75T Petrex SS, Poly-pale Ester 1, Pentalyn G.

(4) Plasticizers:-In view of the generally water-immiscible nature of lacquer plasticizers, their selection is also wide open for formulations suitable for the purposes of this invention. As long as suitable plasticizers for wood finishing lacquers are well described in the art, a few typical examples are given only. organic phosphates, phthalate esters, castor oil, blown castor oils, esters of. ricinoleic acid, esters of adipic acid, esters of sebacic acid, hydroabietyl alcohol and some of its esters, methyl ester of rosin acids, hydrogenated methyl ester of rosin acids, epoxy esters, amongst others.

EMULSIFYING AGENTS There are many emulsifying agents, which are suitable for making w-ater-in-oil lacquer emulsions according to this invention. Examples are:

Morpholine soaps of fatty acids, like morpholine oleate or linoleate,

Diethylenetriamine soaps of fatty acids, like the oleate land linoleate,

Pine oil,

Sodium sulfite solubilized quebracho extract,

Pine oil,

Organophilic non-ionic emulsifying agents, like, eg the Spans of Atlas Powder Company,

According to this invention acetic acid in the water phase promotes stability of water-in-oil emulsions. Also small amounts of water soluble salts dissolved in the water phase, promote the formation of water-in oil emulsions. Examples of such salts are: sodium chloride and ammonium sulfate.

The sum of this invention, as already stated, is to emulsify as little as possible amount of water in the lacquer, which amount is still sufficient to cause the required increase in filling power. Water phases, which contain emulsifiers forming oil-in-w-ater emulsions, when added in increments to an oil phase, will form first a water-in-oil emulsion and only after the water phase concentration reaches a critical point, will the initially formed water-in-oil emulsion convert to an oil-in-water emulsion. Therefore, water phases which contain oil-in-water type .mulsifying agents can also be used in this invention, if hey are incorporated into the lacquer phase below the ideal concentration where the conversion to oil-in-water ulsion occurs. As an example ammonium lauryl sulcan be mentioned, which in the dry film would lose ally ammonia and could be utilized to accelerate thermosetting of the amino-aldehyde resins present in the composition.

EMULSIFICATION METHODS The methods of emulsification follow the general procedure of emulsion technology. High speed agitator-s are preferred. Advantageous results can be obtained by enclosed turbine type high speed agitators, such as the Eppenbach Homomixer. Passage through a colloid mill is usually not necessary, but in some cases may be advantageous. Generally any efiicient emulsifying equipmentis suitable.

The emulsifying agents can be either added to the oil phase or to the water phase, or to both, depending on the nature of the emulsifying agent and the selection of the Method as outlined under the heading of General Outline of Invention. I prefer to add the water phase to the oil phase in preparing the emulsions of this invention.

The viscosity of an emulsion can be regulated by various means. Increasing the percentage of the water phase will increase the viscosity in a water-in-oil emulsion. Lowering the particle size of the dispersed phase, will also increase the viscosity of the emulsion. Increasing the viscosity of the outside phase, also called continuous phase, will also increase the viscosity of the emulsion. Therefore, in orderto produce the lowest possible viscosity, if that is desired, the percentage of the Water phase should not be too high, the particle size of the water phase should not be lowered below that required for stability and the lacquer which forms a continuous phase, should be formulated with as low viscosity as practical.-

ILLUSTRATIVE EXAMPLES OF LACQUERS SUIT- ABLE FOR CONVERSION INTO WATER-'IN-OIL EMULSIONS AND SOLVENT MIXTURES THERE- FOR To illustrate the lacquer formulations, a few lacquers are given here below as examples, which however, should not be considered as limiting the invention. For illustration purposes suitable solvent mixtures are given first.

Illustrative Suitable Solvent Mixture TABLE IA 5 Solvent 3-1 8-2 8-3 8-4 S-5 3-6 5-7 8-8 Butanol l- 10 11 11 2O Butyl acetate".-- 66.5 42 35 27 29 Octyl acetate W'eight, parts. 100 100 100 100 100 100 100 100 TABLE IB Solvent 8-9 3-10 Butyl acetate 13. 4 7. 7 Octyl acetate 14. 3 7. 7 M.I.B K 29.3 35.8 M.11A l? 7. 7 D.I.B.K 14.3 7. 7 Xylene 28. 7 33. 4

Solvent formulations 8-1 to 8-10 represent weight percents. Lacquers made with these solvent mixtures will be discussed further below. Solvent mixtures 8-11 to S49 are given in volume percents. Solvent mixtures 8-1 to S-10 do not contain the wetting alcohol of the nitrocellulose.

TABLE II Solvent 8-14 5 5 25 4o 25 x nne nn- 15 2o 20 1o 10 38.5 15 15 43 Lacq. (111-... 16 24 45 Vol. parts- 100 100 100 100 100 100 100 100 100 1 The butanol in solvent mixtures 8-11 to S-21 contains the wetting alcohol of the nitrocellulose.

'lhe butanol in solvent mixtures 8-11 to S-21 contains the wetting alcohol of the nitrocellulose.

NOTE.Abbrevia.tions used in tables IIII-M.E.K. is methyl ethyl ketone; M.I.B.K. is methyl isobutyl ketone; M.I.B.C. is methyl isobutyl carbiuol; M.n-B.K. is methyl n-butyl ketone; M.n-A.K. is methyl' n-amyl ketone; E.l3.K. is ethyl butyl ketone; E.A.K. is ethyl amyl ketone; Lacq. D11. 1s lacquer diluent naphtha.

The solvent mixtures 8-1 to 8-21 represent greatly varying evaporation curves. The proper solvent mixture is to be selected according to the application method by which the lacquer will be applied. Sanding lacquers have usually faster evaporating solvent mixtures. Gloss lacquers, which are not sanded,.dry slower.

Brushin g lacquers have still slower evaporating solvent mixtures. High solvency lacquers are designed to permit high solid contents when applied at room temperature by spraying. Hot spray lacquers utilize heat in addition to thinners to obtain spraying consistency.

Lacquer formulations with these solvent mixtures are illustrated below.

Illustrative Lacquer Formulations Table IV shows some illustrative data on proportions of solvent mixture to nitrocellulose with solvent mixtures S1 to S-8.

TABLE IV Weight parts of solvent mixture Weight parts of butanolwet-nitrocellulose Type of nitrocellulose (see) Solvent mixture The balance is plasticizer and/or resin. The lacquers of S1, S-3 and S-8 contain also pigments.

Illustrative Lacquer Examples A to F illustrate six lacquers useful for wooden surfaces utilizing solvent mixtures S-l1 to S-16.

TABLE V Lacquer example Non,volatile ingredients, parts by weight:

RS. 18-25 cps. nitrocellulose Non-oxidizing alkyd, 30

34% oil, coconut, 100%- Ester gum 80 Dioctyl phthalate 20 20 40 40 40 Castor oil 20 Solvent mixture used S-ll S-l2 S-13 S-14 S-15 S-lfi Total non-volatile, weight percents 20. 6 16.2 20.2 31.0 27.0 31.0

The balance between non-volatile and 100% is the 50 solvent mixture.

Illustrative Lacquer Examples G to I illustrate floor lacquers for wood.

Lacquer Examples J and K show the formulation of a high solvency (high solids) lacquer and of a hot spray lacquer with solvent mixtures S-20 and S-21 repectively.

LACQUER EXAMPLE J.HIGH (HIGH SOLIDS) TYP Non-volatile ingredients, parts by weight:

SOLVENCY E R8. nitrocellulose, /2 second dry 100 Aroplaz 905 (dry basis) 300 Melmac 2458 (Cymel 245-8), (dry basis)" 30 Solvent mixture used S-21 Non-volatile, weight percents 30.0

LACQUER EXAMPLE K.I-IOT SPRAY LACQUER TYPE Constitution of non-volatile content, percents by weight:

R.S. nitrocellulose, A second, dry 28.6 Cellolyn 502 34.3 Lewisol 33 17.1 Dioctyl phthalate- 10.0 Raw castor oil 10.0

Total 100.0 As optional ingredient for flatting Syloid 308 5.0 Solvent mixture used: S-2O Total solids as sprayed 35.0

Recommended spraying temperature: 165 F.

The next following lacquer examples illustrate ethy cellulose lacquers suitable for wood finishing.

Lacquer exa Non,volatile csntent, weight percent Ethyl cellulose N200 Ethyl cellulose K-14- Oellolyn 102 Raw castor oil Dewaxed Dammar Weight percents Solvent mixture for Lacquer Examples L and M consists of 20% butanol and 80% xylene, by weight. Other ethylcellulose solvent mixtures may be used also. Nonvolatile content may range from 30% to 40%.

Lacquer Examples N, O and P represent comparative lacquers of the older conventional sanding and polishing type. Example N is the conventional lacquer not made for emulsion work and O and P are two comparative lacquers suitable for emulsion work, however, difiering in solvent mixture. The wetting alcohol in Example N is denatured ethyl alcohol, whereas in Examples 0 and TABLE VI P it is butyl alcohol. Parts are by weight.

Lacquer example Lacquer examples G H I N 0 P N onvo1atile ingredients, parts by Weight: RS. nitrocellulose %-second RS. %-second nitrocellulose (dry) 100 100 100 RS. mtrocellulnse 60-80 Second Alkyd reSln, 30-34% on, coconut (100%) so 30 ett alcohol s ecifie ve) Alkyd resin, 45% oil, caster (100%) 30 Et yl 81001101 Maleie modified rosin ester 2O 20' Butyl alcohol... Raw castor oil 25 25 25 Butyl cetate 25 25 25 Butyl Cellosolvo i l) i i l) BLIl'IEI-R'KK' 10' 00 u Octylacetate. 15, 00 1 0 I D.I.B.K 15.00 10.00 The balance between non-volatile and 100% 1s the sol- 30 vent mixture. Commercial examples of resins in Tables g m; i o r 0 11 #15 7.10 71 10 7110 1 u y p t aate 21.40 21.40 2L4 V and are P 70 Arochem 520 ry) 04.13 64.13 64.12 Shoat oil non-oxidizing alkyd: Beckosol 1308. Totalweizht parts 801 3r 351 37 2 Modified pentaerythntol rosin ester: Pentalyn G, Cellor 8 lyn 104. Nonoxidizing alkyd, coconut, 3034% oil: Aroplaz 905. The manner how these 3 lacquer examples are c0m- Malerc modified rosm ester: Lewlsol 33. 75 pared will be discussed below under the examples of the lacquer emulsions. Note, that Lacquer Examples and P are free of ethyl alcohol, as the wetting alcohol used in their preparation was butanol. The solvent mixture in Lacquer Example 0 was S-9 and in Lacquer Example P was -10, described further above.

Inexpensive lacquers are illustrated by Lacquer Examples Q, R, S and T. They are made of washed film scrap, which is similar to RS. nitrocellulose -20 seconds grade. The latter can be replaced for the film scrap on dry basis and the small plasticizer content of the film scrap can be disregarded. Before going into the formulations of these lacquers two solvent mixtures have to be described, which both can be used in practice as thinners" to reduce lacquer viscosity to spraying consistency. Solvent mixture 3-22 is a conventional inexpensive lacquer thinner, utilized in solvent type lacquers. Solvent mixture S-23 is a suitable thinner to adjust viscosity of the water-in-oil emulsion lacquers of the instant invention, but in addition can also be used as the original solvent mixture with which a lacquer is prepared.

Thinner solvent mixtures (parts are by Weight) S-22, 3-23, convcnspecial tional But'mnl 6, 0 12 50 Butyl acetate 4. 0 Ethyl acetate-.- 30.0 M.I.B.K 31. 25 D.1.B.K 12. 50 Toluene 30.0 Xylene 31. 25 ill-flash na h tln 12. 50 Lacquer diluent naphtha 30. 0

Total 100. 0 100. 0

Lacquer examples (parts by weight) Q R S '1 Film Scrap 100. 0 100. 0 100. 0 100. 0 But-anol 5 .0 112.0 50. 0 112.0 Ethanol O Butyl acetate--- .0 Ethyl acetate.-. I.B.K 200. 0 125.0 201.0 D.I.B.K 80.0 50. 0 80. 0 Toluene 222. 6 Xylene 359. 0 125. 0 125.0 Lacquer diluent naphtha. 272.0 Hi-flash naphtha 143. 6 50.0 50.0 Thinner S-22... 196.0 Thinner S-23 Ester gun solution, 70 in toluene 191. 4 191. 4 191. 4 Tricresyl phosphate 20.0 Beekosol 1307 EL, 50% N.V 200.0 Lewisol 33 solution, 50% in toluene 200.0 Yelkin TTS, 70% in xylene 4. 8 Pine oil 46. 0

' Total Weight 1, 382. 0 1, 382. 0 1, 382. 0 1, 138. 8

Yelkin TTS is soya lecithin. Lewisol 33 is a maleic modified rosin ester (rosin modified maleic alkyd). Beckosol 1307 is a semi-drying oil modified phthalic alkyd resin, 41% oil content. Lacquer Q represents the conventional model lacquer, not formulated for emulsion work. Lacquer Examples R and S are comparative lacquers to Q, formulated however to be suitable for this invention. Lacquer Example R has somewhat more expensive solvent mixture, which evaporates slower, than the solvent mixture of Lacquer Example S. The solvent mixture of Lacquer Examples R and T are of the S-23 type, when we omit from consideration the solvents added by the resin solutions.

Lacquer Example T is a more or less self-emulsifying type lacquer, as will be seen in the discussion under the emulsified lacquer examples.

10 Lacquer Examples With Chlorinated Rubber Clear chlorinated rubber lacquers for wood finishing are used for fire retardant purposes. Tung oil is a suitable plasticizer or chlorinated paraifin. Hard resins may be present to provide gloss.

Pigmented Lacquers and Sanding Sealers The pigments are water-insoluble and therefore do not influence the emulsification properties. Even pigments which may cause some slight formulation problems in oil-in-water type emulsions, do not cause similar complications in water-in-oil emulsions. This is particularly true for the low water content type emulsions of the instant invention. Therefore, if the lacquer and its film forming ingredients are properly formulated, as outlined above, they produce satisfactory water-in-oil emulsions for the purposes of this invention.

Sanding sealers contain usually zinc stearate or a similar pigment type ingredient and therefore they fall logically under the pigmented lacquer category. The lacquer formulation, as far as solvents and film formers are concerned, should follow the teachings outlined above.

Satisfactory sanding sealer non-volatile content may be illustrated by the following ranges:

Percent by weight R.S. nitrocellulose, /z-second 50-55 Lewisol 33 14-15 Raw castor oil 14-16 Dibutyl phthalate 114-15 Lewisol 33 may be replaced by Arochem 520 or other similar resin. Two practical sanding sealer formulations are given here below. The clear lacquer in these formulations could be either the lacquer of Example 0 or P, both thinned with solvent mixture S-23 to the same solids content as lacquer of Example N, or the lacquer of Example R. Lacquers O and P yield higher grade sanding sealers and lacquer of Example R a less expensive grade.

Zinc stearate- Zinc Steal-ate Paste for Preparation of Sanding Sealers Weight percent ILLUSTRATIVE EMULSIFED LACQUER EXAMPLES Example 1 (Method 1) A water phase is first prepared. 10 weight parts of Methocel l5 cps. (methylcellulose 1S cps. grade) is dissolved in Weight parts of water and to the resulting parts of Methocel solution 0.5 part of glacial acetic acid are added, to acidify the water phase. To 100 weight parts of lacquer 10 weight parts of the water phase are added, by incorporating the water phase into the lacquer phase in increments under agitation. An Eppenbach Homomixer is a suitable equipment for this purpose.

By this method close to 10% of water is emulsified into the lacquer. The method of Example 1 can be varied by using instead of the 10% Methocel .15 cps. solution a 3% Methocel cps. solution, or a 3% Methocel 4000 cps. solution, each containing 0.5% glacial acetic acid, based on 100 parts Methocel solution. The presence of the acetic acid is not essential, but it improves emulsion stability. The proportions are given in glacial acetic acid to establish concentration relationship. However, commercially available aqueous acetic acid solutions can be used, making correction for their water content.

Lacquer Examples A to M and R and S may be treated according to Example 1. They can be thinned to spraying viscosity by thinner solvent mixture 8-23, in case of the nitrocellulose lacquers and by xylene in case of the ethylcellulose lacquers. If the method is applied to the chlorinated rubber lacquers of Examples U and F, xylene or turpentine can be used as solvent. Where the hot spray method is applicable, instead of thinner addition, partial heating to somewhat elevated temperatures may also be utilized.

If the water-in-oil lacquers are applied in a comparative manner by applying the same weight unit of solids per area .unit and compared with the corresponding ,unemulsified lacquer, the emulsion lacquers show considerable improvement in filling power.

Should it be desirable to increase the water content in the Example 1 type lacquer emulsions, water can be added directly .to the water phase, prior to incorporation. In such .cases no further ,methylcellulose addition is required; however, the 0.5% acetic acid quantity should be added also for theadditional water.

Lacquer Example Q servesas control for Lacquer Examples R and S, after the latter are converted to emulsions.

Example 2 (Method II) In this example the lacquer is converted to an oil phase, as follows:

To 100 weight parts of lacquer add 0.44 weight parts of Yelkin TTS solution, 70% in xylene, and add 5.0 weight parts of pine oil, yielding 105.44 weight parts of oil phase.

A water phase is prepared by mixing 268.5 weight parts of water with 30.0 weight parts of 10% Methocel 15 cps. grade solution in water and 1.5 weight parts of glacial acetic acid, yielding 300.0 weight parts of Water phase.

The water phase contains about 1% dry Methocel and 0.5% acetic acid.

According to this example 100 Weight parts of Water phase is incorporated first into 100 weight parts of oil phase and after the emulsion is properly formed, an additional 100 weight parts of oil phase are added. This example produces water-in-oil emulsions with about 33% water content. In this example the same lacquers can be utilized, as in Example 1. They can also be thinned with solvent mixture S23 to spraying consistency, with or without using the hot spray method. In testing the emulsion lacquers versus the corresponding solution lacquers equal weight parts of solids (non-volatile content) should be applied to a given surface area unit. In-

crease in filling power is quite remarkable with the emulsions of Lacquer Examples R and S when compared with control Lacquer Example Q. The increase is more evident and surprising on this type of lacquer which represents comparatively low non-volatile contents at spraying viscosity. In this example soya lecithin (Yelkin TTS) and pine oil are used to improve the emulsification qualities of the lacquer oil phase.

Example 3 (Method III) In this example Lacquer Example T is used as oilphase, without additions. This lacquer contains Yelkin TTS and also pine oil and thereby demonstrates the selfemulsifying type. Otherwise the same water phase and procedure is followed, as described in Example 2. weight parts of water phase are first emulsified into 100 weight parts of lacquer and after the emulsion is formed, an additional 100 weight parts of lacquer is incorporated into the emulsion. The Water content of the finished lacquer emulsion, also in this case, is about 33% by weight. Application and comparative testing of this lacquer is carried out as described in Examples 1 and 2. It shows great increase in filling power.

Sanding sealers are of great importance in finishing wooden furniture surfaces. Sanding sealers No. 1 and No. 2 can be converted to water-in-oil emulsions by the Methods I or II described in Examples 1 and 2. If both the sanding sealer and the lacquer are of the water-in-oil emulsion type, the improvement obtained by the instant process becomes more pronounced.

Example 4 (Method IV) In this example comparative lacquer emulsions are prepared from Lacquer Examples 0 and P, to be compared with Lacquer Example N. The latter represents the conventional solvent type lacquer and is thinned by thinner solvent mixture 8-22 to spraying viscosity. As can be seen from the Lacquer Examples N, O and P, all 3 lacquers have the same non-volatile content formulation and contain the same film formers in the same proportion. They differ in non-volatile percentage, i.e. they contain differing quantities of solvents and the solvent compositions differ also. In this example the Lacquer Examples 0 and P are convented, while their emulsions are prepared, to the same N.V. percentage as that of Lacquer Example N.

Water-in-oil emulsions 0m- Lacquer Example 0 (weight parts) Lacquer Example P (weight parts) Clear lacquer Yelkin TTS, 70% in xylene. Pine oil Water phase of Example, 2.... Solvent mixture S-23 Total The formulation of Lacquer Example N ends also With 801.35 weight parts. The three lacquers are thinned to spraying viscosity. Lacquer of Example N is thinned with solvent mixture 8-22 and the emulsions of O and P are thinned with solvent mixture S23. They are tested and compared in the manner described in Examples 1 and 2.

When applied at equal weight of non-volatile content per surface unit, the water-in-oil emulsions of Lacquer Examples 0 and P-have greatly increased filling power, when compared to that of Lacquer Example N. This elfect is enhanced if water -in-oil sanding sealers are applied under and P and conventional solvent type sanding sealer is applied to the solution lacquer.

It should be noted, that in the instant process and products it is of advantage to keep the water-in-oil emulsion status of the coating up to the point that the major portion of the water evaporates. This means, that a conversion to an oil in-water type emulsion, during the drying process, should be avoided. Many lacquer solvents evaponate faster than water and thereby facilitate conversion of the water-in-oil emulsions to oil-in-water emulsions during drying. Therefore, in order to prevent this occurrence, the preferred solvent mixtures for this invention contain slow evaporating solvents. This will secure that solvent should be present in sufficient quantity at the time of drying until the major portion of the water evaporated and the film solidified to a degree where emulsion conversion does not occur anymore. Many of these solvents have high solvency power and reduce the viscosity of laquers to a greater extent, than some of the conventional solvents used in solution lacquer formulations. Further, in view of the fact that water is inexpensive compared to lacquer diluent type solvents (like the hydrocarbons), solvent mixtures of higher true solvent concentration can be utilized to match the cost of a solvent mixture with lower true solvent concentration and higher diluent type solvent content. As long as the water acts s, in the instant process by its physical state of being present in emulsified state and not by the viscosity increase obtained by the emulsification, it is possible to formulate an O and P type lacquer emulsion by proper solvent selection, which at equal NV. content to Lacquer Example f; NQwill have the same viscosity when thinned to be suitable for spraying. Emulsions of Lacquer Examples 0 and P, made according to Example 4, illustrate this point. Viscosity can further be lowered by increasing the concentration of higher solvency solvents in the solvent mixture.

REMARKS In Emulsion Examples 1 to 4 the water phase contained methylcellulose. Other water-in-oil emulsifying systems may be used instead of the ones used in these examples. A few are mentioned here below for illustrative purposes:

(a) Calcium naphthanate 0.12% and a nonionic waterin-oil emulsifier, like Span 85 or Span 20 in the amount of 0.12%, based on the total emulsion. The pH of the water phase is adjusted to 4.5 by acetic acid.

(b) Morpholine oleate, e.g. at 0.6% concentration, based on the weight of the emulsion.

(c) Methyl-cellulose coated aluminum rosinate of the maleic adduct of rosin is dispersed in a hydrocarbon solvent to a 25% slurry. 0.8% of this slurry is employed simultaneously with 0.31% of morpholine oleate, percents based on the weight of the emulsion.

(d) 0.12% of a 25% aqueous solution of sodium sulfite solubilized quebracho extract, 0.3% pine oil, 0.06 of glacial acetic acid, percents based on the weight of the emulsion.

(e) Morpholine oleate 0.31%, dispersed in the lacquer oil phase and acetic acid in the water phase to bring the pH of the water to 4.5.

(f) A solution is prepared from a high viscosity type aluminum naphthen'ate in a solvent mixture of xylene and V.M. & P. Naphtha, mixture in the proportion of 1:1. 1% of this solution is used as the emulsifying agent, incorporated into the lacquer phase.

(g) Diethylenetriamine oleate is used in the amount of 0.6%, based on the weight of the emulsion and incor- .porated into the lacquer oil phase. Acidifying the water phase improves the emulsion obtained.

For the purposes of this invention SS-type nitrocellulose is dissolved in solvent mixtures containing a substantially water-immiscible alcohol and a hydrocarbon solvent. Mixtures of butanol and xylene in suitable proportions illustrate such solvent mixtures.

I claim:

1. A stable water-in-oil emulsion clear wood finishing lacquer composition having improved filling power, consisting of (a) a clear wood finishing lacquer, (b) a waterin-oil emulsifier and (c) at least about 5% and not more than about 30% Water emulsified in said lacquer and the composition having a viscosity suitable for application by spraying, all percents being by weight, the film former of said lacquer essentially consisting of :a member of the class consisting of nitrocellulose, ethylccllulose and an admixture of nitrocellulose with ethylcellulose, the volatile organic solvent mixture of said lacquer being of the type which does not dissolve in water to a concentration exceeding about 20% solvent content and which does not dissolve substantially more than 20% water.

2. The composition of claim 1, in which the volatile organic solvent mixture of the lacquer is of the type which does not dissolve in water to a concentration exceeding about 10% solvent content and which does not dissolve substantially more than about 10% water.

3. The composition of claim 1, in which the emulsified water is not more than about 20%.

4. The composition of claim 1, which is a clear furniture lacquer comprising in the non-volatile component of the composition nitrocellulose, a plasticizer and a resin, said pl asticizer being a member of the class consisting of organic phosphates, phthalate esters, esters of ricinoleic acid, esters of adipic acid, esters of sebacic acid, hydroabietyl alcohol, methyl ester of rosin acids, hydrogenated methyl ester of rosin acids, epoxy esters, castor oil and blown castor oil, said resin being a member of the class consisting of polyhydric alcohol esters of rosin, rosin modified rnaleic esters of polyhydric alcohols, oil modified alkyd resins, epoxy resin resters, hydrocarbon resins, urea-formaldehyde and melamine-formaldehyde resins and nitrocellulose compatible acrylic resins.

5. A sanding sealer composition comprising the composition of claim 1 wherein the film former of said lacquer consists essentially of nitrocellulose and also comprising z-inc stearate.

6. The composition of claim 1, in which the emulsified water comprises methylcellulose dissolved therein, said methylcellulose being present in quantities ranging from about 1% to about 10% based on the weight of the emulsified water, the percents being weight percents.

7. The composition of claim 1, in which the emulsified water comprises methylcellulose dissolved therein and also comprises acetic acid, said methylcellulose being present in quantities ranging from about 1 weight percent to about 10 weight percent based on the weight of the emulsified water and the quantity of the acetic acid being sutficient to acidify the water phase end to bring the pH below 7.

8. The composition of claim 1, wherein the total film former non-volatile content in the lacquer phase of the emulsion is from about 16% to about 40%, the percents being by weight.

9. The composition of claim 1, wherein the essential film former is present in the lacquer phase in weight percentages of from about 7% to about 30%, said percentages being based on said lacquer phase.

10. The composition of claim 1, wherein the nonvolatile component of the composition comprises a lacquer resin as auxiliary film former, said lacquer resin being a member of the class consisting of polyhydric alcohol esters of rosin, rosin modified maleic esters of polyhydric alcohols, oil modified alkyd resins, epoxy resin esters, hydrocarbon resins, urea-formaldehyde and melamine-formaldehyde resins and nitrocellulose compatible acrylic resins.

11. The composition of claim 1, wherein the nonvolatile component of the composition comprises a lacquer plasticizer, said plasticizer being -a member of the class consisting or organic phosphates, phthalate esters, esters of ricinoleic acid, esters of adipic acid, esters of sebacic acid, hydroabietyl alcohol, methyl ester of rosin acids, hydrogenated methyl ester of rosin acids, epoxy esters, castor oil and blown castor oil.

12. A method of finishing wooden surfaces by first peparing a clear wood finishing lacquer as lacquer phase, next forming a stable water-in-oil emulsion by emulsifying water into the lacquer phase in the presence of a water-in-oil emulsifying agent with the aid of agitation in a manner that at spraying consistency the emulsion should contain between about 5% and 50% water content, applying said emulsion by spraying to a wooden surface and drying the coated surface, all percents being by weight, the essential film former of said lacquer being a member of the class consisting of nitrocellulose, ethylcellulose and an admixture of nitrocellulose with ethylcellulose, the volatile organic solvent mixture of said lacquer being of the type which does not dissolve in water to a concentration exceeding about solvent content and which does not dissolve substantially more than about 20% water.

13. The method of claim 12, in which at spraying consistency the water content does not exceed about 20%.

14. The method of claim 12, in which the emulsion is applied at elevated temperatures by the hot spray method.

15. The method of claim 12, in which the water-in-oil emulsion lacquer composition is prepared in concentrated form and is thinned before application with a solvent mixture reducing its viscosity to spraying consistency.

16. A method of finishing hard wood surfaces of furniture whereby first a sanding sealer composition, which is a Water-in-oil emulsion, is applied to said surface followed by the application by spraying of at least one coat of a water-in-oil emulsion clear furniture lacquer composition comprising nitrocellulose as essential film former and drying the coated surface, said water-in-oil emulsion clear furniture lacquer composition consisting of (a) a clear wood finishing lacquer, (b) a water-in-oil emulsifier and (c) at least about 5% and not more than about 50% water being emulsified in said lacquer, said composition having a viscosity suitable for application by spraying, the volatile organic solvent mixture of said lacquer being of the type which does not dissolve in water to a concentration exceeding about 20% solvent content and which does not dissolve substantially more than 20% water, all percents being by weight.

17. A method of finishing wooden surfaces by preparing a clear wood finishing lacquer, incorporating therein a water-in-oil emulsifier whereby said lacquer is converted to a self-emulsifying substantially water-free lacquer, converting the said self-emulsifying lacquer to a water-in-oil emulsion having spraying viscosity by incorporating therein water and thinner with the aid of agitation, applying said emulsion by spraying to the wooden surfaces and drying the coated surfaces, said water-in-oil emulsion containing between about 5% and Water content at the time it is applied to the wooden surface, the essential film former of said lacquer being a member of the class consisting of nitrocellulose, ethylcellulose and an admixture of nitrocellulose with ethylcellulose, the volatile organic solvent mixture of said lacquer being of the type which does not dissolve in water to a concentration exceeding about 20% solvent content and which does not dissolve substantially more than about 20% water, all percents being by weight.

18. A method of finishing wooden surfaces by preparing a water-in-solvent emulsion by emulsifying in the presence of a water-in-oil emulsifying agent water into a volatile lacquer solvent mixture which consists of substantially water-immiscible solvents, incorporating the water-in-solvent emulsion ito a substantially water-free clear wood finishing lacquer, thereby simultaneously forming a water-in-oil lacquer emulsion composition and thinning it to spraying consistency, applying said composition by spraying to a wooden surface and drying the coated surface, said water-in-oil lacquer composition containing between about 5% and 50% water content at the time it is applied to the wooden surface, the essential film former of said clear wood finishing lacquer being a member of the class consisting of nitrocellulose, ethylcellulose and an admixture of nitrocellulose with ethylcellulose,

the volatile organic solvent mixture of said lacquer emulsion composition being of the type which does not dis-- solve in water to a concentration exceeding about 20% solvent content and which does not dissolve substantially more than about 20% water, all percents being by weight.

References Cited in the file of this patent UNITED STATES PATENTS 2,044,572 Hollabaugh June 16, 1936 2,323,871 Kienle et al July 6, 1943 2,357,725 Bennett Sept. 5, 1944 2,500,122 Dixon Mar. 7, 1950 2,510,834 Phillips June 6, 1950 2,576,797 Lyons Nov. 27, 1951 2,591,904 Zola Apr. 8, 1952 OTHER REFERENCES Morrison et al.: Jour. Soc. of Chem. Ind., vol. 68, December 1949, page 334.

Claims

1. A STABLE WATER-IN-OIL EMULSION CLEAR WOOD FINISHING LACQUER COMPOSITION HAVING IMPROVED FILLING POWER, CNSISTING OF (A) A CLEAR WOOD FINISHING LACQUER, (B) A WATERIN-OIL EMULSIFIER AND (C) AT LEAST ABOUT 5% AND NOT MORE THAN ABOUT 30% WATER EMULSIFIED IN SAID LACQUER AND THE COMPOSITION HAVING A VISCOSITY SUITABLE FOR APPLICATION BY SPRAYING, ALL PERCENTS BEING BY WEIGHT, THE FILM FORMER OF SAID LACQUER ESSENTIALLY CONSISTING OF A MEMBER OF THE CLASS CONSISTING OF NITROCELLULOSE, ETHYLCELLULOSE AND AN ADMIXTURE OF NITROCELLULOSE WITH ETYLCELLULOSE, THE VOLATILE ORGANIC SOLVENT MIXTURE OF SAID LACQUER BEING OF THE TYPE WHICH DOES NOT DISSOLVE IN WATER TO A CONCENTRATION EXCEEDING ABOUT 20% SOLVENT CONTENT AND WHICH DOES NOT DISSOLVE SUBSTANTIALLY MORE THAN 20% WATER.