CA1276057C - Storage stable paper size composition containing ethoxylated lanolin - Google Patents

Abstract

ABSTRACT
A shelf stable paper size is prepared from a mixture of a substituted cyclic dicarboxylic acid anhydride and an ethoxylated lanolin.

Description

~7 Ei~

STORAGE STAB~E PAPER SIZE COMPOSITION
CONTAINING ETHOXYLATED LANOLIN

This invention relates to a self-emulsifiable paper size composition characterized by improved shelf life and to a method for sizing paper and paperboard therewith. More particularly, the invention relates to a self-emulsifiable paper size composition comprising a mixture of a hydrophobic substituted cyclic dicarboxylic acid anhydride and an ethoxylated lanolin.
Paper and paperboard are often sized with various hydrophobic materials including, for examplel rosin, wax emulsions, mixtures of rosin waxes, ketene dimers, isocyanate derivatives, fatty acid complexes, fluorocarbons, certain styrene-maleic anhydride copolymers, as well as the substituted cyclic dicarboxylic acid anhydrides more particularly described hereinafter. These sizes may be introduced during the actual paper making operation wherein the process is known as internal or engine sizing, or they may be applied to the surface of the finished web or sheet in which case the process is known as external or surface sizing.
In order to obtain good sizing with any of these sizing compounds, it is desirable that they be uniformly dispersed throughout the fiber slurry in a small particle size. It was general practice therefore, to add the sizes in the form of an aqueous emulsion prepared with the aid of emulsifying agents including, for example, cationic or ordinary starches, carboxymethyl cellulose, natural gums, gelatin~ cationic polymers or polyvinyl alcohol, all of which act as protective colloids. The use of such emulsifying agents with or without added surfactants did, however, sufer from several inherent deEiclencies in commercial practice. A
primary deficiency concerned the necessity of utilizing relatively complex, expensive and heavy equipment capable of exerting high ~J

~276i~S7 homogenizing shear and/or pressures, together with rigid procedures regarding em~llsifying proportions and temperatures, etc., for producing a satisfactory stable emulsion of the particular size. Additionally, the use of many surfactants ln conjunction with protective colloids was found to create operational problems in the paper making process such as severe foaming of the stock and/or loss in sizing.
With partlcular reference to the procedures of the prior art which utilized substituted cyclic dicarboxylic acid anhydrides as sizing agents, it was necessary in commercial practice to pre-emulsify with cationic starch and/or other hydrocolloids using relatively rigid procedures with elevated temperatures to cook the starch or hydrocolloids and high shearing and/or high pressure homogenizing equipment. Unless these complicated procedureæ were carefully followed, difficulties such as deposition in the paper system, quality control problems and generally unsatisfactory performance were often encountered.
Many of these problems were overcome in U.S. Reissue Patent No.
29,960 which disclosed the use of a size mixture of these cyclic dicarboxylic acid anhydrides and spec mixture immediately after preparation thereof. The two components were therefore supplied separately to the paper manufacturer who continued the separate storage of the components until their use was required.
It would be described to be able to prepare a size in the form of a shelf stable mixture which could be stored in warehouses ~or periods of six months to a year, which would be self-emulsifiable and would exhibit excellent sizing properties.
We have ~ound that a storage stable self-emulsifiable paper size may be prepared ~rom a mixture o~ 80-99 parts by weight of at least one substituted cyclic dicarboxylic acid anhydride containing hydrophobic -~76~57 substitution and 1-20 parts by weight of ethoxylated lanolin. The mixture is storage stable for extended periods of time, i.e., for at least six months of natural aging, and exhibits excellent sizing properties when emulsified prior to addition to the paper making stock or when added directly to the system and emulsified in-situ.
The sizing compounds contemplated for use herein are the cyclic dicarboxylic acid anhydrides containing hydrophobic substitution. Those substituted cyclic dicarboxylic acid anhydrides most commonly employed as paper sizes are represented by the following formula:
Il C\

: \ ~ - R' ~1 .
o wherein R represents a dimethylene or trimethylene radical and wherein R' is a hydrophobic group containing more than 4 carbon atoms which may be selected from the class consisting of alkyl, alkenyl, aralkyl or aralkenyl groups. Sizing compounds in which R' contains more than twelve carbon atoms are preferred.
Representative of those cyclic dicarboxylic acid anhydrides which are broadly included withln the above formula are sizing agents exemplified in U.S. Pat. Nos. 3,10~,064; 3,821,069, and 3,968,005 as well as by Japanese Patent No. 95,923 and Sho-59-144697.
Thus, th~ substituted cyclic dicarboxylic acid anhydrides may be the substituted succinic and glutaric acid anhydrides of the above described formula including, for example, iso-octadecenyl succinic acid anhydride, n- or iso-hexadecenyl succinic acid anhydride, dodecenyl succinic acid ~2~ ;7 anhydride, dodecyl succinic acid anhydride, decenyl succinic acid anhydride, octenyl succinic acid anhydride, triisobutenyl succinic acid anhydride, etc.
The sizing agents may also be those of the above described formula which are prepared employing an internal olefin corresponding to the following general structure:
R - CH2-CH = C~-CH2-Ry wherein Rx is an alkyl radical containing at least four carbon atoms and Ry is an alkyl radical containing at least four carbon atoms and which correspond to the more specific formula:
R

C - C - CH- CH_ CH- Ry ''\

0'~
wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms, and Rx and Ry are interchangeable. Specific examples of the latter sizing compounds include (l-octyl-2-decenyl)succinic acid anhydride and (1-hexyl-2-octenyl)succinic acid anhydride.
; The sizing agents may also be prepared employing a vinylidene olefin corresponding to the following general structure / CH2 Rx H2C = C~
CH2 Ry wherein Rx and Ry are alkyl radicals containing at least 4 carbon atoms in each radical. These compounds correspond to the specific formula:

~27 o~ ~
C C- C8 - C- C~ _ R
/ 2 4 2 x 0\ CH

0' wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms and Rx and Ry are interchangeable and are represented by 2-n-hexyl-1-octene, 2-n-octyl-1-dodecene, 2-n-octyl-1-decene, 2-n-dodecyl-1-octene, 2-n-octyl-1-octene, 2-n-octyl-1-nonene, 2-n-hexyl-decene and 2-n-heptyl-1-octene.
The sizing agents may also include those as described above prepared employing an olefin having an al~yl branch on one of the unsaturated carbon atoms or on the carbon atoms contiguous to the unsaturated carbon atoms. Representative of the latter olefins are n-octene-l; n-dodecene-l;
n-octadecene-9: n-hexene-l: 7,8-dimethyl tetradecene-6: 2,2,4,6,6,8,8-heptamethylnone-4: 2,2,4,6,6)8,8-heptamethylnone-3; 2,4,9,11-tetramethyl 5-ethyldodecene-5: 6,7-dimethyldodecene-6: 5-ethyl-6-methylundecene-5:
5,6-diethyldecene-5; 8-methyltridecene-6; 5-ethyldodecene-6; and 6,7-dimethyldodecene-4.
The ethoxylated lanolins used herein includes any containing o~ at least about 15 moles ethylene oxide per mole lanolin. Preferred are those containing 25 to 80 moles ethylene oxide. The lanolin base may be hydrogenated or non-hydrogenated. The alkoxylation of such lanolins with ethylene oxide is well known in the art and the materials useiul herein are not limited by their method of preparation. Ethoxylated lanolins containing up to about 80 moLes ethylene oxide are available commercially.

~27~ 7 It is contemplated that the alkoxylation may also be performed using similar levels of propylene oxide however, these adducts are not as readily available and are more expensive.
In accordance with the method of this invention, the size mixture is formed by mixing 80 to 9~ parts by weight of the aforementioned substituted cyclic dicarboxylic acid anhydride with 1 to 20 parts, preferably less than 10 parts, of the ethoxylated lanolin. The use of the latter component in excess of about 20 parts becomes uneconomical in terms of cost and May be detrimental in terms of the papermaking operation. The use of the lower levels of the ethoxylated lanolin may require greater degrees of emulsification as with a turbine or the addition of emulsifying agents.
It is to be recognized that mixtures of various combinations of substituted cyclic dicarboxylic acid anhydrides and/or lanolins of varying levels of ethoxylation may be employed in preparing a particular size mixture, as long as they fall within the scope of this invention.
The mlxture of the appropriate amount of the substituted cyclic dicarboxylic acid and the ethoxylated lanolin may be prepared and held in this form for an extended period of time. Testing results run under accelerated aging conditions indicate, to date, the mixture is still stable and effective as a sizing agent after six months at 50C. When use of the mixture is required, it may be readily emulsified either by pre-emulsifying with ~ater before addition to the paper stock or it may be emulsiEied in situ at any point in the manufacturing operation where adequate agitation is present.
I pre-emulsification oE the size mixture is desired, it may be readily accomplished by adding the sizing components to water in sufficient quantity so as to yield an emulsion containing the substituted -~276~57 cyclic dicar~,oxylic acid anhydride in a concentration of from about 0.1 to 20~ by weight. the aqueous mixture is thereafter sufficiently emulsified merely by stirring with moderate speed agitation or by passing it through a mixing valve, asplrator or orifice so that the average particle size of the resultant emulsion wlll be less than about 3 microns. It is to be noted in preparing the emulsion that it is also possible to add the components of the size mixture to the water separately, and that the emulsion may be prepared using continuous or batch methods.
Emulsification of the mixture readily occurs at ambient temperatures. Thus, the emulsification will occur directly in cold water and heating of the water prior to addition of the sizing mixture is unnecessary.
As to actual use, no further dilution of tha emulsion is generally necessary, The thus-prepared emulsion is simply added tot he wet end of the paper making machine or to the stock preparation system so as to provide a concentration of the substituted cyclic dicarboxylic acid anhydride of from about 0.01 to about 2.0% based on dry fiber weight.
Within the mentioned range, the precise amount of size which is to be used will depend for the most part upon the type of pulp which is being treated, the specific operating conditions, as well as the particular end use for which the paper product is destined. For example, paper which will require food water resistance or ink holdout will necessitate the usa of a higher concentration of size than paper which will be used in applications where these properties are not critical.
~ lternatively, the slze emulsion may be sprayed onto the surface of the formed web at any point prior to the drying step in the concentrations as prepared so as to provide the required size concentration.

~276~i7 The ingredients of the size mixture may also be premixed without water and added to the paper making stock system causing the substituted cyclic dicarboxylic acid anhydride to emulsify in situ in the stock preparation system without the need for prior emulsification in water. As in the case in which the size is emulsified prior to use, the amount of size employed will vary dependine on conditions, however, it will generally be within the range of about 0.01 to 2.0g substituted cyclic dicarboxylic acid anhydride based on dry fiber weight.
As is conventional in synthetic siæing operations, the size mixtures are used in conjunction with a material which is either cationic or is capable of ionizing or dissociating in such a manner as to produce one or more cations or other positively charged moieties. Among the materials which may be smployed as ca~ionic agents are long chain fatty amines, amine-containing synthetic polymers (primary, secondary tertiary or quaternary amine), substituted polyacrylamide, animal glue, cationic thermosetting resins and polyamide-epichlorohydrin polymers. Of particular use are various cationic starch derivatives including primary, secondary, tertiary or quarternary amine starch derivatives and other cationic nitrogen substituted starch derivatives as well as cationic sulfonium and phosphonium starch derivatives. Such derivatives may be prepared from all types of starches including corn, tapioca, potato, waxy maiæe, wheat and rice. Moreover, they may be in their original granule form or they may be converted to pregelatinized, cold water soluble products. Amphoteric natural and synthetic polymers contalning both anionic and cationic groups may also be used eiEectively to deposit and retain the sizing agent on the fiber.

'~

~76~7 Any of the above noted cationic retention agents may be added to the stock, i.e. the pulp slurry, either prior to, a ong with or after the addition of the size mixture or size emulsion in conventional amounts of at least about 0.01~, preferably 0.025 to 3.0%, based on dry fiber weight. While amounts in excess of about 3% may be used, the benefits of using increased amounts of retention aid for sizing purposes are usually not economically justified.
The size mixtures are not limited to any particular pH range and may be used in the treatment of neutral and alkaline pulp, as well as acidic pulp. The size mixtures may this be used in combination with alum, which is very commonly used in making paper, as well as other acid materials.
Conversely, they may also be used with calcium carbonate or other alkaline materials in the stock.
Subsequent to the addition of the size emulsion and retention aid, the web is formed and dried on the paper making machine in the usual manner. In actual paper machine operations, full sizing is generally achieved immediately off the paper machine. Because of limited drying in laboratory procedures however, further improvements in the water resistance of the paper prepared with the size mixtures of this invention may be obtained by curing the resulting webs, sheets, or molded products.
This post-curing process generally involves heating the paper at temperatures in the range of from ~0 to 150C for a period of from l to 60 minutes.
The size mixtures of the present invention may be successfully utili2ed for the slzlng of paper and paperboard prepared ~rom all types of both cellulosic and combinations of cellulosic with non-cellulosic fiber.
~lso included are sheet- like masses and molded products prepared from combinations of ce:Llulosic and non-cellulosic materials derived from ~'t i'~ .

~27~S~

synthetics such as polyamide, polyester and polyacrylic resin fibers as well as from mineral fibers such as asbestos and glass. The hardwood or softwood cellulosic fibers which may be used include bleached and unbleached sulfate (Kraft) bleached and unbleached sulfite, bleached and unbleached soda, neutral sulfite semi-chemical, groundwood, chemi-groundwood, and any combination of these fibers. In addition, synthetic cellulosic fibers of the viscose rayon or regenerated cellulose type can also be used, as well as recycled waste papers from various sources.
All types of pigments and fillers may be added in the usual manner to the paper product which is to be sized. Such materials include clay, talc, titanium dioxide, calcium carbonate, calcium sulfate and diatomaceous earths. Stock additives, such as defoamers, pitch dispersants, slimicides, etc. as well as other sizing compounds, can also be used with the size mixtures described herein.
As noted above, the size mixtures described herein exhibit extended shelf life, and, when emulsified and used in the paper stock system, yield paper products having superior sizing properties, even after these extended storage periods.
In the following examples, all parts given are by weight and all temperatures in degrees Celsius unless otherwise specified.

EXAMPLE I
This example illustrates the use of a size mixture representative of the size mixtures of this lnvention utilized in the form of an aqueous emulsion. This emulsion is compared, in terms of particle size cmd water resistance of the resultlng sized paper, with a conventional emulsion made with a mixture of 2 parts of the mixture with 98 parts of a cooked aqueous dispersion of cationic corn starch (containing sufficient starch to .~

~2'7~5~

provide 0.05a based on dry fiber weight) using a propeller-type agitator at moderate speed (500 rpm) for 10 seconds (Emulsion No. 1). A control was prepared ln accordance with U.S. Reissue Patent 29,960 using 93 parts of the same ASA and 7 parts of polyoxyalkylene alkyl-aryl ether wherein the alkyl group contained 9 carbon atoms, the aryl radic~l was phenol, and the polyoxyalkylene moiety was formed with 9.5 moles of ethylene oxide.
Calculated amounts of the emulsions prepared as described above were added to aqueous slurries of bleached sulfate pulp having a Williams freeness of 400, a consistency of O.S~ and a pH of about 7.6, so as to yield a concen~ration of ASA on dry fiber weight of 0.25~. Then 0.5% alum based on dry fiber weight, was added to the pulp slurry before addition of the sizing emulsions. Sheets were formed in accordance with TAPPI
standards, dryed on a rotary print drier (surface temperature approx. 90 C.) then cured for 1 hour at 105C and conditioned overnight at 22C. and 50~ R.H. before testing. The basis weight of these sheets was 55 lbs.
(24.75 kg.)/ream (24 X 36 inch, 61 x 91 cm. - 500 sheets).
The Hercules Size Performance Test (HST) was employed to compare the ink resistance of the sheets prepared. The test comprises applying an amount of acid ink (pH 2.3) to the upper paper surface. With the use of a photoelectric cell, the underside of the paper is monitored for reflectance. The time it takes for the ink to cause a decrease in reflectance from 100~ to 80~ is the paper's HST time. The HST of the paper is a measure of the sizing performance of a given size. The longer the HST time, the better the si7e is.
The average particle size (APS) was measured by optical microscopic observation using a calibrated graduated eye piece under 400-600X
magnification.

~ .

~ ~7iEi~

Table I presents the average particle size (APS in microns) and internal sizing data (HST in seconds) for the above-described emulsions.

TABLE I

Accelerated h~in~
Fresh1 Month 6 Months Bmulsion HST APSHgT AES HSr AES
Control 248 <1u 0 20u 0 50u 1 266 <1u275 <1u 328 1-2u Both the emulsion quality (shown by particle size) and sizing performance (shown by the HST results) indi~ate that there is no loss in perfonmance with the use of the size employing the ethoxylated lanolin, whereas after only one month accelerated aging, the control ma~e a poor eml11sion with no sizing.

E~LPLE II
~ixtures of ASA and ethoxylated lanolin were prep~red as in Example I
with hydrogenated ethoxylated lanolin of varying levels of ethylene oxide (E.O.) substitution. These mixtures were evaluated (fresh) for emulsiEication and sizing perfonnanc~e~ Fift~en moles of ethylene oxide provid0d minimally acceptable performance. With 27, 40, and 75 rnoles of ethylene oxide excellent results were obtained.

TA~LE II

Moles of E.O. Fre~h 3- Months APS HST APS HST
~ u * >25 *
<5u 188 7 193 27 <2u 247 2 237 <1u 233 1 243 >1u 256 1 240 * Emulsion was too poor to evaluate.

i57 E~L~LE III
This example shows a comparison of direct (unremulsified) addition and pre-emulsified addition to the stock with both freshly made and three month ~accelerated) aged sizing mixtures. m e pre-emulsified product was prepared us,ing the procedure of Enulsion 1 in Example I. With direct addition of the ASA/hydrogenated ethoxylated lanolin mixtures the emulsification occurs in-situ due to the shear inherent to the system. In this case, the mixture of Example I was added directly to a slurry of bleached sulfate pulp at 1.5~ consistency in a laboratory Valley beater and beaten very lightly for a few minutes. The pulp was then diluted to 0.5% consistency, and 0.4~ on dry fiber weight of the cationic starch described in Example I was added separately to the slurry to act as a retention aid during sheet formation. & eets were then fonmed, conditioned and tested in the HST test as described In Example I.

lST~ELE III

Pre-Emulsified Direct Pulp A~dition Addition Emulsion HST APS H~ST APS

Freshly made control 256 <1u 248 <1u 20 One month aged control 0 20u 0 30u Freshly made mixture 268 <1u 252 <1u One month aged mixture 273 <1u 261 <1u m e results show that the ethoxylated lanoli~/ASA mixtures p~ovided better sizing and equivalent particle size compared to the control as described in Example I by both pre-emulsification and direct c~ddition and that one month accelerated aging had no adverse effect on the performance of the mixtures.

7~157 EX~a~ lV
In this example the hydrogenated ethoxylated lanolLn was evaluated as an emulsifier for four difEerent cyclical dicarboxylic acid anhydrides prepared as in Example I usin~ 7 parts of the ethoxylated lanolin and 93 parts of the anhydride. m e results show that good perfonmance could be achieved wil~h all four anhydride structures.

TAELE rv _ Fresh Emulsions HST APS

10 Alkenyl succinic acid anhydride 278 <1u Iso-octadecenyl succinic acid anhydride 164 <1u Hexapropylene succinic acid anhydride 267 2u 15 1-oct~l, 2-decenyl succinic acid anhydride 319 <1u E~M~E V
In this example the mixture of hydrogenated ethoxylated lanolin, prepared as in Example I, was compared to three o~her classes of emulsifiers described in U.S. Reissue Pat. 29,960. Even though these emulsifiers showed improved stability over the polyoxyalkylene alkyl aryl ether emulsifiers, used as a control in Example I, the degree of stability d oe s not approach the level of that achieved by use of ethoxylated lanolin as described herein.
TABLE V
Freshly Made One Month Aged Emul~ions HST ~PS HST APS

1 264 <1u * 20u 2 267 ~1u * 20u 3 176 3u 18 8u 4 197 2u 27 3u 271 <1u 243 ~1u ~ 27~i~57 1. Polyoxyalkylene alkyl-aryl ether (as in the control of Example I) 2. Polyoxyalkylene alkyl ether wherein the alkyl group contains 12 carbon atoms and the polyoxyalkylene moiety was fonmed with 6 moles of ethylene oxide.
3. Polyoxyethylene moncoleate ester wherein the molecular weight of the polyoxyethylene moiety was 400.
4. Polyoxyeth~lene dilaurate ester wherein the molecular weight of the polyoxyethylene moiety was 600.

5. Hydrogenated ethoxylated lanolin.
* Eml~sions too poor to evalu~te.
These results show that upon aging only the ethoxylated lanolin retains 100% of its original performance. When freshly made the ethoxylated lanolin exhibited at least equivalent performance to all of the other emulsifiers.
EX~MPLE Vl In this example the level of ethoxylated lanolin varied from 1-20%, as shown in the table to ascertain the effert of high levels in ~he sizing mix~ure. The mixtures and emulsions were prepared in accordance with Example I but varying the relative amounts of ethoxylate~ lanolin and ASA.
TABLE Vl Emulsion HST APS
Control 210 1u 1% ethoxylated lanolin 230 ~2u 5% ethoxylated lanolin 228 <1u 25 10% ethoxylated lanolin 177 <1u 15~ ethoxylated lanolin 145 <1u 20~ ethoxylated lanolin 140 <1u Ihis data shows that levels as low as 1% work effectively9 a~d that 20%, while acceptable, causes reduced sizing results.

~ ~27~57 ..

` EX~MP$E VqI
m is example shows that an anhydrous nonrhydrogenated eth~xylated lanolin works as well as the hydrogenated ethoxylated lanolin when the sizing mixture is freshly made and after three and one-half months ; 5 accelerated aging. Mixtures and emulsions were prepared and evaluabed as in Example I.

TABLE VII
Freshly Made 3,.5 Mon s Rged EmulsionHST APS HST AES

10 Nonrhydrcgenated lanolin 285 >1u 306 >1u Control (of Ex. I)294 ~1u ~ 20u In summary, the invention is seen to provide the prackitioner with a size mixture useful in the manufacture of sized paper products. ~he size mixture is shelf stable over an extended period of time7 and is easily emulsified when desired for use under a wide variety of paper making conditions to provide superior sized paper products.

Claims (11)

1. A paper size comprising a self-emulsifiable mixture of 80 to 99 parts by weight of a cyclic dicarboxylic acid anhydride represented by the formula:

wherein R represents a dimethylene or trimethylene radical and wherein R' is a hydrophobic group containing more than 4 carbon atoms which may be selected from the class consisting of alkyl, alkenyl, aralkyl, or aralkenyl groups and 1 to 20 parts by weight of an ethoxylated lanolin containing at least 15 moles ethylene oxide per mole lanolin.

2. A paper size as claimed in claim 1 wherein the cyclic dicarboxylic acid anhydride is selected from the group consisting of:

wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms, and Rx and Ry are interchangeable;

wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms and Rx and Ry are interchangeable.

3. A paper size as claimed in claim 1 wherein the ethoxylated lanolin contains 25 to 80 moles ethylene oxide per mole lanolin and is present in an amount less than 10 parts by weight of the mixture.

4. A method for sizing paper products comprising the steps of a) providing a paper stock system;
b) forming, in the absence of high shearing forces and under normal pressures, a sizing emulsion comprising from 80 to 99 parts of a substituted cyclic dicarboxylic acid anhydride represented by the formula:

wherein R represents a dimethylene or trimethylene radical and wherein R' is a hydrophobic group containing more than 4 carbon atoms which may be selected from the class consisting of alkyl, alkenyl, aralkyl, or aralkenyl groups; from 1 to 20 parts of an ethoxylated lanolin containing at least 15 moles ethylene oxide per mole lanolin; and water;
c) forming a web from the paper stock system;
d) dispersing said emulsion within the paper stock either before or after formation of said web but prior to passing said web through the drying stage of the paper making operation in an amount sufficient to provide a concentration of the substituted cyclic dicarboxylic acid anhydride of from 0.01 to 2.0%, based on dry fiber weight.

5. A method as claimed in claim 4 wherein the cyclic dicarboxylic acid anhydride is selected from the group consisting of:

wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms, and Rx and Ry are interchangeable;

wherein Rx is an alkyl radical containing at least 4 carbon atoms and Ry is an alkyl radical containing at least 4 carbon atoms and Rx and Ry are interchangeable.

6. A method as claimed in claim 4 wherein the ethoxylated lanolin contains 25 to 80 moles ethylene oxide per mole lanolin and is present in an amount less than 10 parts by weight of the mixture.

7. A method as claimed in claim 4 wherein the sizing emulsion is formed in situ within the paper stock system.

8. A method as claimed in claim 4 wherein the sizing emulsion is formed prior to introduction into the paper stock system.

9. A method as claimed in claim 8 wherein the size mixture is emulsified in a sufficient quantity to yield an emulsion containing the substituted cyclic dicarboxylic acid anhydride in a concentration of from 0.1 to 20%, by weight of the total emulsion, prior to addition to the paper stock system in an aqueous dispersion of a cationic or amphoteric retention agent.

10. A method as claimed in claim 4 wherein there is dispersed within the paper stock prior to the conversion of the paper stock into a dry web, at least 0.01% based on dry fiber weight, of a cationic retention agent.

11. Paper or paperboard prepared by the method of claim 4,