US3736164A - Organophobic and hydrophobic surface coatings - Google Patents

Abstract

SURFACE COATING COMPOSITIONS COMPRISING A BLEND OF AN ACTIVE FLUORINE-CONTAINING PHOSPHATE MATERIAL, A CHELATING AGENT AND A SOLVENT, AND THE USE OF SUCH SURFACE COATING COMPOSITIONS IN PROVIDING OIL, GREASE AND SOLVENT RESISTANCE TO TREATED CELLULOSIC MATERIALS ARE DISCLOSED.

Description

United States Patent Office Patented May 29, 1973 3,736,164 ORGANOPHOBIC AND HYDROPI-IOBIC SURFACE COATINGS Melville Willard Ulfner, Media, Pa., assignor to Air Products & Chemicals, Inc., Allentown, Pa. No Drawing. Filed July 16, 1971, Ser. No. 163,417 Int. Cl. C08b 25/02 US. Cl. 106-213 Claims ABSTRACT OF THE DISCLOSURE Surface coating compositions comprising a blend of an active fluorine-containing phosphate material, a chelating agent and a solvent, and the use of such surface coating compositions in providing oil, grease and solvent resistance to treated cellulosic materials are disclosed.

BACKGROUND OF THE INVENTION The present invention relates to novel mixtures of active fluorine-containing phosphate material, chelating agent and volatile solvent which can be used to impart oil, grease and solvent resistance to treated materials, particularly cellulosic packaging materials.

Cellulosic materials, such as paper and paperboard, have been used for over a century to package a wide variety of consumer goods. Today, cellulosic packaging is used for everything from cake mixes, shoes, candy, tobacco, butter, breakfast cereals, soap, and dog food to lubricated metal parts. Until the mid-l950s, when fluorochemical sizing agents were first introduced, products having a relatively high grease content, as well as products subject to moisture loss or gain, were of necessity marketed in a wax paper, plastic or metal foil bag or liner prior to being inserted into a paperboard container. By sealing the inner bag or liner an effective barrier to grease and moisture was provided. The disadvantage of this bag-in-the-box approach is the expense and handling problems involved in the use of two containers to achieve the desired result.

As an alternative to the bag-in-the-box approach, laminated packaging materials have been used in which a barrier coating of wax, plastic, or the like, which has thickness of approximately 0.0001 inch to 0.0015 inch, is laminated to the packaging material. This laminating approach, like the bag-in-the-box approach, tends to diminish the economic advantages sought in the use of cellulosic packaging materials. Normally, the laminated layer must be applied in a separate step and care must be taken to obtain uniformity in the laminated layer in cluding an absence of pinholes, tears and the like, and good adherence to the cellulosic materials.

Since the commercial introduction of fluorochemical sizing agents, fluorochemicals have been used to provide oil resistance for cellulosic materials. The use of such fluorochemicals has the advantage of eliminating the necessity of having to provide a separate barrier of plastic film, waxed paper or metal foil to obtain oil repellency characteristics. When a surface is treated with fluorochemicals, the resulting surface has very low surface energy which prevents wetting of surface fibers by aqueous materials, most animal, vegetable and mineral oils, and by many solvents.

conventionally, both the topside and backside of the cellulosic packaging materials are treated with fluorochemicals to obtain the desired barrier characteristics. Although both sides can be treated with the same fluorochemical composition, typically the composition used for the topside and the backside are different because the resistance characteristics needed for each side are different. In any event, the coating compositions used commercially are similar in the fact that the pH for such compositions lies in the range of 8.0 to 9.5 and the fluorochemicals employed for such coating compositions are linear fluorochemicals.

The backside fluorochemical coatings which have heretofore been used have been applied from either an aqueous fluorochemical solution, containing no additives, or in combination with a starch, typically oxidized starch. The starch is added to prevent curling of paperboard during drying. In some instances, the cellulosic material which is to be treated with fluorochemical coating is first primed with the pentasodium salt of diethylenetriaminepentaacetic acid from an alkaline aqueous solution. The results of such treatment have been erratic, have caused the treated paperboard to be tenderized, and have diminished the water resistance of the paperboard.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the oil, water and solvent resistance of cellulosic materials.

Another object of this invention is to provide novel surface coating compositions which result in imparting oil, water and solvent repellency to cellulosic materials.

Still another object of the present invention is to provide a method of treating cellulosic packaging material with surface coating composition of the present invention on the backside and treating the topside with a conventional surface coating composition in order to obtain improved oil, water and solvent resistance of both sides of the packaging material.

In accordance with the present invention, surface coating compositions are prepared by blending water with between 1 and 25 active parts by weight of fluorine-containing phosphate material, between 0.01 and 2 active parts by weight of chelating agent and 1 to 10% by Weight of solvent based on the total wet weight of the composition, including the active solids, water of dilution and solvent. The resulting surface coating compositions are used to impart oil, water and solvent resistance to cellulosic materials, such as paper, cardboard, paperboard, etc.

The active fluorine-containing phosphate materials which can be used in accordance with the present invention have the formula (R L) Z [Formula I] where: R, is:

C F -EC F where C F represents a monosubstituted or disubstituted cyclohexane ring; b is 0 or 1; n is an integer between 0 and 10 when b is 1 and n is an integer between 4 and 20 when b is 0;

L is:

SO N(R)(CH O, where R is an alkyl group having 1 to 10 carbon atoms; or

(CH ),,O, where a is the integer 1 or 2; y is an integer of 1 or 2, and

Z is:

P(O)(OM) where x is the integer 1 or 2; and M is a water-solubilizing cation of the group consisting of alkali metal, ammonium and substituted ammonium when x is 1, and each M is independently selected from the group consisting of hydrogen, alkali metal, ammonium and substituted ammonium when x is 2.

The preferred chelating agent is the disodium salt of ethylenediaminetetraacetic acid. Preferred solvents include n-butanol and methyl ethyl ketone. Optionally, a binder can be added to the surface coating compositions. The preferred binder is hydroxyethylated starch.

The resulting surface coating compositions have a pH less than or equal to 7. The combination of the chelating agent and the solvent serve to wet the treated fibers thereby causing improved fluorochemical wicking. The optional hydroxyethylated starch binder tends to prevent coated board from curling and also tends to improve the oil and solvent resistance of the coating composition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As set forth above, the surface coating compositions of the present invention are prepared by mixing between 1 and 25 parts by weight of the composition of an active fluoride-containing phosphate material with between 0.01 and 2 parts by weight of chelating agent and between 1 and 10% of the total wet weight of solvent. Water is added to make'up the balance of the coating composition.

Among the active fluorine-containing phosphate materials which may be used in accordance with the present invention are the following materials:

FEC F EI-CH OPO (OH) 2 CF (CF CH OPO (OH) 2 2H(NCH CH OH) The C F group of R; [in Formula I] can be in the 1, 2 or 3 position of the cyclohexane ring {C F The alkali metal of the water-solubilizing cation M in Formula I is either sodium or potassium. The substituted ammonium salts may be obtained using the commonly available, water-soluble, primary, secondary or tertiary amines, such as methyl amine, diethyl amine, monoethanol amine, diethanol amine, morpholine, triethanol amine and bis(3-hydroxypropyl)amine.

The preferred chelating agent is the disodium salt of ethylene-diaminetetraacetic acid. Other chelating agents, such as sodium hexametaphosphate, may be employed, but the results are not necessarily equivalent.

In general, water soluble alcohols and ketones may be employed as a solvent. Preferably, the solvent is either n-butanol or methyl ethyl ketone.

Where it is desirable to include a binder, the preferred binder is hydroxyethylated starch. When a binder is incorporated, the amount of chelating agent is generally reduced.

The following table sets forth the broad and preferred ranges of the ingredients of the surface coating compositions of the present invention.

Parts by weight of composition With binder:

Fluorine-continuing phospate material. Chelating agent Binder; Solvent 1 to 25 and preferably 5 to 10.

0.01 to 2 and preferably 0.01 to 1.

25 to 200 and preferably 75 to 100.

1 to of total wet weight anl preferably 2 to 6% of total wet weight.

Water. To the desired solids content. Without binder:

Fluorlne-eontnining phosphate 1 to and preferably 5 to 10.

material.

Chelating agent 0.01 to 2 and preferably 0.01 to 1.

Solvent 1 to 10% of total Wet weight and preferably 2 to 6% of total wet weight.

Water To the desired solids content.

defoamers, lubricants and the like. Pigments, for example, include titanium dioxide, calcium carbonate, zinc oxide, hydrated alumina, barium sulfate, zinc sulfide, calcium sulfite, calcium sulfate, talc, etc. Lubricants include sodium stearate, ammonium stearate, calcium stearate, aluminum stearate, and the like. These additives are intermixed with the surface coating compositions of the present invention by conventional blending methods. Solid additives can be finally comminuted and stirred into the functional surface coating compositions or an aqueous emulsion of the additive can be blended with the surface coating compositions.

The treatment level required to get functional performance will vary, depending on the severity of the end use requirements and the formulation of the coating. Typically, the compositions of the present invention are applied to the cellulosic material in order to apply 0.01 to 1% by weight of active fiuorochemical on the weight of the treated material and preferably to apply between 0.025 and 0.25% by weight of active fluorochemical on weight of the treated material.

Any means of applying a uniform coating of sufiicient treatment level to provide an effective barrier can be employed. Effective coating means include air-knife coaters, brush coaters, cast coaters, flexible blade coaters, gravure coaters, reverse roll coaters, transfer roll coaters, and the like. The resultant thin coatings are adequate for most applications. If slightly thicker coatings are desired, the surface coating compositions of the present invention may be applied in two or more coatings or certain thickening additives may be incorporated, such as cellulose ethers.

While the surface coating compositions of the present invention are aindried to useful continuous coatings, it will be understood that these coating compositions can be dried by any suitable means in order to reduce the drying time. The resulting coatings exhibit good adhesion to paper and other cellulosic material and provide effective oil, water and solvent resistance.

It has been observed that when cellulosic material such as paperboard is treated on one side with conventional fiuorochemical sizing agents and on the other side with the surface coating compositions of the present invention a synergistic effect is obtained and the overall characteristics of the treated material are improved.

The following methods are employed for testing surface coating compositions applied to cellulosic materials. These tests include TAPPI RC-338 Kit Test and the flat peanut oil holdout test.

The RC-338 Kit Test is a procedure for testing the degree of repellency and/or wicking characteristics of paper and paperboard which are treated with fluorochemical-type sizing agents. The following apparatus, specimens and reagents are required:

Apparatus (1) Bottles, a set of labeled glass stoppered bottles to serve as stock bottles for the Kit Number reagents.

(2) Dropping bottles, a set of small glass dropping bottles with ground-in glass pipets and rubber bulbs, and labeled as the bottles above, to dispense the set of reagents as required and to prevent contamination, mixing and evaporation.

(3) Absorbent cotton.

(4) Timer, stopwatch or electric timer.

Specimens Five specimens (of at least two by two inches).

Reagents (1) Castor oil, C.P. grade.

(2) Toluene, C.P. grade.

(3) Heptane, C.P. grade.

Mixtures of the aforementioned reagents are prepared in accordance with the following table and stored in the labeled glass-stoppered stock bottles.

Each test specimen is placed on a clear flat surface, testside up, with care being taken not to touch the area to be tested. A drop of the test solution from an intermed ate Kit Number is dropped on the test area from a height of about one inch. The timer is started simultaneously with the application of the test solution. After seconds, excess fluid is removed with a clean swatch of absorbent cotton. Repellency is determined by examination of the wetted area. A darkening of the specimen indicates that penetration has occurred.

The procedure set forth above is repeated, as required, until penetration occurs. The highest numbered solution which stands on the surface of the specimen for 15 seconds without penetration is used as the test rating.

The flat peanut oil holdout test provides an accelerated comparison of relative rates at which oils or greases found in materials contained by flexible packages may be expected to penetrate these packaging materials. The following apparatus, specimens and reagents are used for practicing this test:

Apparatus 1) Tube of any rigid material, one inch inner diameter and not less than one inch height, the ends of which have been smoothed.

(2) Pipette or medicine dropper calibrated to deliver 1.1 milliliters.

(3) Round-grained sand, Ottawa Cement testing sand screened to pass a No. and be retained on a No.

sieve.

(4) Oven, designed to maintain 140 degrees, within plus or minus one Fahrenheit degree, and large enough to test four samples simultaneously.

(5) Plane surface, glass plate cut one inch longer than the paper.

(6) Glass plate, 2 by 2% inch, to insure intimate contact of the test sheet with the back-up sheet and minimize reagent loss.

(7) Metal weights, 3 /2 by /2 by inch, to be placed around the periphery of the test sheets to insure flatness.

Specimens The samples are cut to a minimum of four by four inches. Mixed reagent peanut oil is prepared by adding 1.0 gram of an oil soluble red dye to 100 milliliters of peanut oil.

In accordance with the testing procedure, the samples are preconditioned for 24 hours at 73 degrees F. ,and relative humidity.

Each sample is placed on a sheet of coated 80 pound book paper mounted to the glass plate. Half the number of samples are placed topside up; the other half backside up. Metal weights are placed around the periphery. The tube is placed at the center of the sample and five grams of sand is poured into the tube. The tube is removed and using the pipette 1.1 milliliters of colored peanut oil is added to the sand. The glass plate is placed over the oil saturated sand in order to insure intimate contact of the test sheet with the backup sheet. The resulting sample is then placed in 140 degree F. oven.

Each sample is checked every fifteen minutes for the first hour, every thirty minutes for the next four hours, and then at convenient intervals. As soon as the first red stain appears on the absorbent paper, the time is noted. The time elapsed in hours between placing the sample in the oven and the appearance of the first red stain is recorded. For conventional fluorochemical treated board, such as that used to contain Ralston-Purina dog food, the flat peanut oil holdout is 2 hours at 60 degrees C. for the backside and 8 hours at 60 degrees C. for the topside.

The invention will be illustrated by Examples IV and X, it being understood that there is no intention to be necessarily limited by any details thereof since variations can be made within the scope of the invention. The other examples are comparative examples which help to illustrate the nature of the invention.

EXAMPLE I Paperboard base stock, Brown Companys 24 point bleached manila lined bending news (88 pounds per ream), was coated on its topside with a composition obtained by blending Composition (a) with Composition (b) until a homogeneous mix was obtained:

Composition (a) Parts by weight (1) tap water 44.00

(2) soya protein (Delta type) 7.75 (3) methylpolysiloxane (defoamer) .009 (4) borax 0.23 (5) 26 degree B aqua ammonia 0.93 (6) tap water 3.73

Total 56.73

Ingredients 1) through (4) of Composition (a) were heated to to degrees F. with agitation, and maintained at that temperature for one hour. While continuing the agitation, the composition was cooled to room temperature. The pH was adjusted to between 9.0 and 9.5 with item (5) and item (6) was added to make up for lost water.

Ingredient (8) in Composition (b) was slurried in ingredient (7 under high speed agitation. The additional ingredients were then added in the order shown with aqua ammonia being used to adjust the pH to about 9.5.

The topside coating was applied to obtain a transfer of 0.05% active fluorochemical on the weight of board.

The blackside of the board was primed with 0.5% of the pentasodium salt of diethylenetriaminepentaacetic acid and then coated with the same linear fluorochemical used in Composition (b) in order to transfer 0.05 active fluorochemical on the weight of the board.

After both topside and backside coatings were applied, the coated paperboard was dried at degrees F. for 15 minutes. By analysis, the board was shown to contain a total of 0.1% linear fluorochemical on the weight of the board.

Using the RC-338 and flat peanut oil holdout testing procedures, both sides of the board were tested. The results of this testing is shown below:

Flat peanut oil holdout 116-338 test, hours Side tested rating at 60 C.

Backside 6 l Topside 6 3.

EXAMPLE II The procedure of the Example I was repeated except that the backside was not primed and the backside coating composition used was a combination of the linear fluorochemical, the 'pentasodium salt of diethylenetriaminepentaacetic acid and oxidizsed starch in accordance with the following backside coating composition.

Ingredients: Parts by weight Tap water 1394.0 Oxidized starch 88.0 Methylpolysiloxane (defoamer) 3.7

% pentasodium salt of diethylenetriaminepentaacetic acid 5 .0 30% linear fluorochemical (anionic watersoluble mixture of the diethanolamine salts of the perfluoroheptyl carbinol esters of phosphoric acid) 26.2

The backside coating composition was applied to Brown Companys bleached manila linear bending to yield a 0.05% fluorochemical pickup on the weight of board. The resulting board was tested, as in Example I, with the following results:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 6 1 Topside 7 8 EXAMPLE III When Example II was repeated without employing any fluorochemical for either the topside or the backside coating compositions, the following results were obtained:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 1 0. 25

Topside 1 0. 75

EXAMPLE IV Example II is repeated, using the following backside coating composition:

Ingredients: Parts by weight Tap Water 1349.0

Methylpolysiloxane (defoamer) 3.7 10% disodium salt of ethylenediaminetetraacetic acid 5.0 Methyl ethyl ketone 63.0 30% linear fluorochemical (anionic watersoluble mixture of the diethanolamine salts of the perfiuoroheptyl-carbinol esters of phosphoric acid) 26.2

This backside coating composition was applied to the bleached manila lined bending news to obtain the total 8 percent of fluorochemical content of the board, by analysis, of 0.1%. The following results were obtained:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 6 15 Topside 7 15 Comparison of Examples I through IV shows the dramatic improvement obtained using the backside coating composition of Example IV.

EXAMPLE V The topside coating procedure of Example I was employed to coat Rockford Paper Mill Companys 20 point Kraftback (72 pounds per ream).

The backside of this Kraftback was coated with the following composition:

In preparaing the backside coating composition, the oxidized pearl starch was cooked for 15 minutes at a temperature between and degrees F.

As in Example I, the backside coating composition was applied to yield 0.05% active fluorochemical on the board weight.

The following results were obtained when the backside of the board was tested:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 0 1 EXAMPLE VI Following the procedure of Example V, Rockford Paper Mill Companys 21 point chipback (78 pounds per ream) was tested and the following results were obtained:

Flat peanut oil holdout RC338 test, hours Side tested rating at 60 C.

Backside 4 0. 25

Topside 7 2 EXAMPLE VII Similarly when Brown Companys 23 point chipback (88 pounds per ream) was treated and tested in accordance with Example V, the following results were obtained:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 6 1 Topside 6 3. 5

EXAMPLE VIII Following the procedure of Example I, employing as the fluorochemical 30% cyclim fluorochemical (described below), Rockford Paper Mill Companys 21 point chip back (78 pounds per ream) was treated on the topside.

Unlike Example I, the following backside coating composition was employed:

Ingredients: Parts by weight Tap water 1394.0 Hydroxyethylated starch 88.0 Methylpolysiloxane (defoamer) 3.7 n-Butanol 63.0

30% cyclic fluorochemical (anionic watersoluble mixture of the diethanolamine salts of the 1,1 dihydropenfluorocyclohexylmethyl esters of phosphoric acid) 26.2

The backside coating composition was applied to obtain analysis of the board of 0.1% fiuorochemical based on the weight of the board.

When the resulting board was tested the following results were obtained:

Flat peanut oil holdout RC-338 test, hours Side tested rating at 60 C.

Backside 7 1.

Topside 6 1. 5

EXAMPLE IX When Example VIII was repeated using oxidized starch for the hydroxyethylated starch in the backside coating composition, both the backside and top side fiat peanut oil holdouts at 60 degrees C. were about 0.5 hour.

EXAMPLE X Following the procedure of Example I, the topside coating composition was prepared in which the cyclic fluorochemical (anionic water-soluble mixture of the diethanolamine salts of the 1,1-dihydroperfluorocyclohexylmethyl esters of phosphoric acid) and the linear fluorochemical (anionic water-soluble mixture of the diethanolamine salts of the perfiuoroheptyl carbinol esters of phosphoric acid) were substituted for each other.

The backside coating composition employed is set forth by the following table:

Ingredients: Parts by weight Tap water 1394.0 Hydroxyethylated starch 88.0 Methylpolysiloxane (defoamer) 3.7

10% disodium salt of ethylenediaminetetraacetic acid 5.0 n-Butanol 63 .0 30% fluorochemical 26.2

Total 1579.9

As with the topside coating composition, both the cyclic fluorochemical and the linear fluorochemical were substituted for each other as the fluorochemical used in the backside coating composition.

The performance of the coating compositions on three different board stocks is shown below at 0.1% pickup.

Flat peanut It will be seen from comparison of the examples that by treating at least one side of the cellulosic material with composition in accordance with the invention, the repellency characteristics of the treated material were improved over the characteristics obtained using the standard treating techniques, even with the same fluorochemicals. It will also be seen that the cyclic fluorochemicals outperform the linear fluorochemicals.

From the foregoing, it will be seen that this invention is well adapted to obtain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the system. As can be seen, the surface coating compositions of the present invention, comprising active fluorine-containing phosphate material, chelating agent and solvent in the indicated proportions, are superior to coating compositions of conventional fiuorochemical sizing agents. In all cases, the coating compositions of the present invention can be applied in a one-step application, thereby eliminating the necessity for two separate applications or even priming the surface before fiuorochemical overcoat is applied.

The fluorochemical coating compositions of the present invention are especially useful in improving the protection of label papers which are exposed to oils, protection of paperboard for both external stains and stains from internal oil contents and for the protection of cellulosic sheets which are to be Waxed.

While the present invention finds particular applicability to the treatment of cellulosic materials such as paper and paperboard, the invention is also applicable to other cellulosic materials, including cardboard, including corrugated board; construction boards, including insulating board; wet machine board, including binder board for book covers; laminated board, including board prepared pi a laminating glassine paper to paper board; and the Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.

What is claimed is:

1. A surface coating composition having a pH equal to or less than 7 consisting eswntially of (a) 1 to 25 parts byweight of composition of a fluorinecontaining phosphate material,

(b) 0.01 to 2 parts by weight of composition of chelating agent,

(c) 1 to 10% of total wet weight of composition of a solvent selected from water soluble alcohols and ketones, and

((1) water, wherein the structural formula of the fluorine containing phosphate material is R L Z,

where R; is:

n 2n+f ti lo bi where C F is a monosubstituted or disubstituted cyclohexane ring, where b is 0 or 1, n is an integer between 0 and 10 when b is 1 and n is an integer of from 4 to 20 when b is 0;

L is:

-SO N(R) (CH O, where R is an alkyl group having 1 to 10 carbon atoms; or

where a is the integer 1 or 2; y is an integer of 1 or 2, and Z is:

where x is the integer 1 or 2 and M is a Water solubilizing cation of the group consisting of alkali metal, ammonium and substituted ammonium when x is l, and each M is independently selected from the group consisting of hydrogen, alkali metal, ammonium and substituted ammonium when x is 2.

2. The surface coating composition of claim 1 in which the chelating agent is disodium salt of ethylenediaminetetraacetic acid.

3. The surface coating composition of claim 1 wherein the solvent is a water soluble alcohol.

4. The surface coating composition of claim 3 in which the solvent is n-butanol.

5. The surface coating composition of claim 3 in which the solvent is methyl ethyl ketone.

6. The composition of claim 1 which also includes a binder.

7. The composition of claim 6 in which the binder is hydroxyethylated starch in the amount between 25 and 200 parts by weight of the composition.

8. A coated cellulosic material having on at least one surface thereof a coating composition having a pH equal to or less than 7 consisting essentially of a fluorine containing phosphate material, a chelating agent and a solvent selected from water soluble alcohols and ketones, wherein the structural formula of the fluorine-containing phosphate material is R L Z,

where R; is:

n 2n+1 e 1o' b where C F is a monosubstituted or disubstituted cyclohexane ring, where b is or 1, n is an integer between -0 and 10 when b is 1 and n is an integer of from 4 to and b is 0; L is:

where R is an alkyl group having 1 to 10 carbon atoms;

where a is the integer 1 or 2;

y is an integer of 1 or 2, and Z is:

where x is the integer 1 or 2 and M is a water solubilizing cation of the group consisting of alkali metal, ammonium and substituted ammonium when x is l, and each M is independently selected from the group consisting of hydrogen, alkali metal, ammonium and substituted ammonium when x is 2.

9. A process for treating cellulosic material, which process comprises applying a surface coating composition having a pH equal to or less than 7 to the cellulosic material in order to deposit from 0.01 to 1% by weight of active fluorochemical on the weight of the cellulosic material and then drying the treated cellulosic material, wherein the coating composition is prepared by blending (a) l to parts by weight of composition of a fluorinecontaining phosphate material,

(b) 0.01 to 2 parts by weight of composition of chelating agent,

(0) to to 10% of total wet weight of composition of a solvent selected from water soluble alcohols and ketones, and (d) water, wherein the structural formula of the fluorine-containing phosphate material is R;L Z,

where C F is a monosubstituted or disubstituted cyclohexane ring, where b is 0 or 1, n is an integer between 0 and 10 when b is 1 and n is an integer of from 4 to 20 when b is 0; L is:

2 2) 2 where R is an alkyl group having 1 to 10 carbon atoms;

where a is the integer 1 or 2;

y is an integer of 1 or 2, and Z is:

where x is the integer 1 or 2 and M is a water solubilizing cation of the group consisting of alkali metal, ammonium and substituted ammonium when x is 1, and each M is independently selected from the group consisting of hydrogen, alkali metal, ammoninth and substituted ammonium when x is 2.

10. The process of claim 9 wherein the surface coating composition is applied to the cellulosic material by a roller coating.

11. The process of claim 9 wherein the surface coating composition is applied to the cellulosic material by a wire wound rod coating blade.

12. The process of claim 9 wherein the cellulosic material is paper.

13. The process of claim 9 wherein the cellulosic material is paperboard.

14. The process of claim 9 wherein the surface coating composition applied to the paperboard also contains hydroxyethylated starch.

15. The surface coating composition of claim 1 wherein the solvent is a water soluble ketone.

References Cited UNITED STATES PATENTS 3,245,816 4/1966 Schwalbe 106-214 3,002,844 10/1961 Reiling 106-146 2,927,916 3/ 1960 Magariello 260-119 2,803,656 8/1957 Ahlbrecht 260-944 3,096,207 7/1963 Cohen 260-955 2,932,589 4/1960 Meyer 1 106-154 3,664,987 5/1952 Moyer et a1. 106-177 THEODORE MORRIS, Primary Examiner US. Cl. X.R. 106-287 R; 117-156