US 3311532 A
Description (OCR text may contain errors)
March 28, 1967 IOOOO R. J. KULICK ETAL 3,311,532
KETENE DIMER PAPER SIZING COMPOSITIONS INCLUDING ACYL COMPOUND EXTENDER AND PAPER SIZED THEREWITH Filed March 17, 1965 HEXADECYL KETENE DIMER ADDED BASED ON DRY WEIGHT 0F FIBERS STEARIC ACID ADDED BASED ON' WEIGHT 0F HEXADECYL KETENE DIMER INVENTORS. RUSSELL J. KULICK EDWARD STRAZDINS ANTHONY R. SAVINA ATTGRNEY United States Patent KETENE DIMER PAPER SIZING (ZOMPOSITIONS ENCLUDIING ACYI. CGMPOUND EXTENDER AND PAPER SEIZED THEREWITH Russell Eoseph Kuiicir, Port Qhester, N.Y., and Edward Strazdins and Anthony Ralph Savina, Stamford, Coma, assignors to American Cyauamid Company, Stamford, (101111., a corporation of Maine Filed Mar. 17, 1065, Ser. No. 440,584 16 filaims. (Cl. 162179) This is a continuation-in-part of our copending application Ser. No. 254,157, filed Jan. 28, 1963, now abandoned.
The present invention relates to paper-sizing compositions comprising a hydrophobic paper-sizing ketene dimer and an acyl compound which acts as extender therefor. The invention includes the manufacture of sized paper by use of these compositions, and the resulting paper.
Hentrich et al. US. Patent No. 2,411,860 (1946) discloses that paper is rendered water-resistant when treated with higher ketene dimers, and Arlt US. Patent No. 2,901,371 (1959) discloses that in the emulsification of these ketene dimers, to prepare them for use as sizing agents for paper, the higher fatty acids are particularly advantageous emulsifying agents.
The discovery has now been made that the effectiveness of the higher ketene dimers as paper-sizing agents is greatly enhanced when they are present on the cellulose fibers of the paper in conjunction with a comparatively large amount of a hydrophobic substantially water-insoluble saturated substantially straight-chain acyl compound. We have found that in preferred embodiments these acyl compounds (which include the higher fatty acids) improve the sizing action of the ketene dimers in three principal respects.
(1) They act as extenders for the ketene dimers; that is, they permit the amount of paper-sizing ketene dimer which has been previously required to achieve a given level of sizing, to be decreased. We have found that by this means the amount of ketene dimer in a typical sizing operation can be decreased by about 50%75%. Since suitable acyl compounds are cheap and freely available and since paper-sizing ketene dimers are comparatively expensive, the present invention permits a major decrease in the cost of manufacturing sized paper by the use of ketene dimers.
(2) They act as accelerators for ketene dimer sizes; that is, they increase the rate at which these ketene dimers develop their sizing when they are heated during drying. We have found it possible by use of preferred acyl compounds to develop in two minutes of heating at about 100 C. substantially the same sizing from paper-sizing ketene dimers as is developed by 30 minutes of similar heating in the absence of such compound.
(3) They act as fortifying agents for the ketene dimers; that is, although they impart comparatively no sizing themselves, they substantially increase the ultimate sizing imparted by the ketene dimer. Ketene dimers are outstandingly effective sizes for paper, capable of imparting a very high degree of Water and lactic acid resistance to paper. The present invention achieves an absolute improvement in the amount of ultimate sizing imparted by the paper-sizing ketene dimers.
The foregoing improvements do not become apparent unless the weight of the added acyl compound is at least about of the weight of the ketene dimer.
The invention thus in its principal aspect resides in compositions consisting essentially of a paper-sizing ketene dimer and an efiective extending amount, in excess of about 10%, based on the weight thereof, of a hydrophobic substantially water-insoluble, substantially straight-chain acyl compound as extender for the ketene dimer. Forms or states in which the components of the composition are present are described below.
The invention includes the manufacture of sized paper by use of the aforesaid components, and the present invention broadly consists in the utilization of substantial amounts of an acyl compound (as hereinafter more fully described) in conjunction with one or more paper-sizing ketene dimers in any of the established paper-making processes. The invention is thus essentially an improvement in established paper-making processes. This is an important advantage because the invention does not require any change in established methods for the manufacture of sized paper by the use of ketene dimer as sizing agents.
Broadly, then, the process comprises depositing a papersizing ketene dimer on cellulose fibers as size together with an effective amount of the acyl compound as extender therefor, followed by heating the fibers to develop the sizing properties of the ketene dimer thereon. The invention does not primarily depend upon the particular means employed for depositing the components of the fibers.
The invention also resides in the resulting paper, which is composed of cellulose fibers sized by a uniformly distributed reacted content of a paper-sizing ketene dimer and by an effective uniformly distributed unreacted surface content of the acyl compound in excess of about 10% of the weight of the ketene dimer as extender therefor. The acyl compound is evidently in uniform admixture with the reacted ketene dimer.
The range over which the acyl compounds act as extender is broader than the range over which they act as accelerator and fortifying agent. Accordingly, in the claims the amount of acyl compound present or used (as the case may be) is defined in terms of the action of the acyl compounds as extender, and is sometimes designated as effective extending amounts, and it will be understood that this includes in each instance the amount in which the acyl compounds act as accelerator and fortifying agent.
The hydrophobic, substantially water-insoluble, saturated, substantially straight-chain acyl compounds used in the present invention are in general the acids, higher fatty acids (i.e., fatty acids which contain 12 carbon atoms or more) and the anhydrides, amides, acid chlorides and aldehydes of these acids. By the term substantially Water-insoluble we mean that the compounds dissolve in water to the extent of less than 1% and preferably less than 0.1%, and by the term substantially straight chain, we mean that the compounds are either precisely straight chain or that whatever branching they contain is of no significant consequence from the point of view of the amount of sizing which is imparted by these compounds.
Suitable acyl compounds include lauric, palmitic, stearic, and arachidic acids, their anhydrides, amides, aldehydes and acid chlorides, and mixtures thereof.
The acyl compounds are most advantageously used alone, but they may be used in admixture with minor amounts of highly branched chain or unsaturated acyl compounds. For example, they may be used in admixture with min-or amounts of oleic acid, oleamide and the branched chain carboxylic acids formed by oxidation of petroleum hydrocarbons, which are tolerated.
The invention is illustrated by the drawing, which shows the effect of stearic acid as extender, as accelerator, and as fortifying agent for the sizing action of hexadecyl ketene dimer. The data are presented in the form of curves A and B and point E and were obtained as follows:
A series of handsheets was prepared by beater addition of hexadecyl ketene dimer (prepared from commercial stearic acid) alone or in admixture with stearic acid as sizing agents. The agents were added as cationic emulsions. In each instance the weight of the hexadecyl ketene dimer (or hexadecyl ketene dimer-stearic acid mixture) was 0.2% of the dry weight of the fibers; the ratio of stearic acid to the ketene dimer is set forth on the lower abscissa. Since in each instance the weight of sizing composition added was constant, the amount of hexadecyl ketene dimer decreased in proportion as the amount of stearic acid increased. The amount of hexadecyl ketene dimer added in each instance as a percentage of the dry weight of the fibers is shown along the abscissa at the top of the drawing.
One set of handsheets was dried for two minutes at 230 F. (corresponding to the cure obtained on a typical paper-making machine), after which the sizing of the sheets was determined by the use of 20% aqueous lactic acid applied at 100 F. under a head of 12". The results were plotted and curve A drawn.
The second set of handsheets was dried for /2 hour at 223 R, which developed substantially all the sizing which the additives were capable of imparting. The results were plotted and curve B drawn. Further details of the process are shown in Example 5 below.
The effect of the acyl compound as extender when the size has completed approximately maximum cure is illustrated by dotted line C which connects points B1 and B2 of curve B. Since the line is substantially horizontal, it shows that in the runs performed, substantially the same sizing is obtained by the use of a hexadecyl ketene dimer and stearic acid mixture wherein the weight of the stearic acid is 100% of the weight of the ketene dimer (point B2) as is obtained by the use of ketene dimer alone (point B1).
The maximum elfective amount of the acyl compound as extender at complete cure has not been ascertained but evidently is substantially in excess of 100% of the weight of the ketene dimer since the dotted position of curve B shows that a substantial amount of sizing is obtained when the weight of the acyl compound is 125 150% of the weight of the ketene dimer. A part of the acyl compound thus evidently acts as inert diluent.
The effect of the acyl compound as extender during the initial development of the sizing action of the ketene dimer is illustrated by horizontal line E connecting points A1 and A3. Line E shows that substantially as good oif the machine sizing is obtained by use of 0.2 g. of a hexadecyl ketent dimer-stearic acid mixture wherein the weight of the latter is about 233% the weight of the former as is obtained by an equal weight of hexadecyl ketene dimer alone.
The effect of the stearic acid as accelerator is illustrated by points A2 and B1 of the drawing. These points show that the presence of about 67% of stearic acid, based on the weight of the ketene dimer, causes 7800 seconds of sizing to develop in 2 minutes at 230 F. (point A2), and that 9650 seconds of sizing are developed by the ketene dimer along after /2 hour at 223 F. (point B1).
The effect of stearic acid as fortifying agent is illus trated by line F, which connects points B2 and G. The latter point represents the approximate ultimate sizing of paper manufactured by addition of 0.1% of hexadecyl ketene dimer in the same manner as the handsheets from which the data of curve A were obtained, and point B2 represents the approximate ultimate sizing of corresponding paper prepared by beater addition of 0.1% of the ketene dimer plus 0.1% of stearic acid. it appears from line F that the stearic acid caused the sizing to increase from 900 seconds to 9,600 seconds, an increase of approximately 8,700 seconds. This increase is a measure of the fortifying action of the acyl compound.
Curve A shows that close to maximum acceleration of the development of sizing per increment of acyl compound present occurs when the weight of the acyl compound is about %25% of the weight of the ketene dimer and that virtually maximum absolute acceleration 4. is obtained when the weight of the stearic acid is 50% to 75% of the weight of the ketene dimer.
Curve B shows that valuable sizing results are obtained even when the wei ht of the acyl compound is in excess of the optimum amounts as extender, accelerator and tortifying agent. The excess amount evidently acts essentially as diluent.
The data of the drawing illustrate typical results so far obtained. Somewhat different curves are obtained depending particularly on the particular ketene dimer and acyl compound used, the total Weight of ketene dimer and acyl compound added (based on the dry weight of the fibers), the pH of the paper-making suspension and the electrostatic sign of the emulsions and the particular emulsifying agents present therein. The eifect of these variables cannot be calculated, and in each instance, therefore, the optimum or the maximum effective amount of the acyl compound as extender or activator and the best choice of emulsifiers can best be determined by a series of laboratory trials.
The components of the compositions of the present invention may be present in several forms or states. They may thus be present as a dry blend of discrete papersizing ketene dimer particles and particles of a suitable acyl compound. If desired, the components may be in solution form and for this purpose benzene or chloroform are suitable solvents. Moreover, the components may be in unitary homogeneous state such as in the composition which is formed by melting the lretene dimer and the acyl compound together, and then chilling the resulting solution, so that the acyl compound is present as a solution in the ketene dimer (or vice versa).
The dry compositions mayinclude one or more emulsifying agents for the ketene dimer and the acyl compound. The emulsifying agent may be non-ionic, cationic, or anionic. When the acyl compound is a fatty acid, acid chloride, or anhydride, the anionic emulsifying agent may be replaced by an equivalent amount of an alkali metal alkali (for example sodium bicarbonate) so as to convert a portion of the acyl compound to a soap when the composition is emulsified with water.
The compositions may contain materials customarily employed in the manufacture of paper which are not incompatible therewith. They may thus contain supplementary inert extenders such as silica or silica gel; starch; pigments and dyes; supplementary sizing agents as for example wax size; scents; hydrophobic, cyclic compounds as for example rosin; and mold growth inhibitors.
The compositions may be prepared for use in the same manner as the paper-sizing ketene dimers have been prepared for use in the past.
Thus the compositions may be dissolved in a volatile organic solvent to form a solution suitable for use as an impregnant.
The compositions are more economically prepared for use by conversion to fluid aqueous emulsions. The emulsions are conveniently prepared by intensively agitating the ketene dimer and the acyl compound together in a volume of water containing one or more emulsifying agents. The temperature of the water is preferably above the melting points of the ketene dimer and the acyl compound. The emulsifying agent may be anionic, cationic, or non-ionic. The resulting emulsion may be homogenized, after which the emulsion is rapidly cooled to prevent formation of aggregates. The invention does not depend upon the particular way in which the emulsions are formed. Alternatively, the two components may be emulsified separately and mixed.
The cationic emulsions may be prepared as is disclosed in Arlt US. Patent No. 3,046,186. The non-ionic and anionic emulsions may be prepared as is disclosed in Downey US. Patent No. 2,627,477 and in Osberg US. Patent No. 2,785,067. Any of the common cationic, anionic and non-ionic emulsifiers may be used for the preparation of the respective emulsions.
Sized paper may be manufactured in any convenient way by use of the solution and emulsions referred to above.
Preformed paper may be sized by impregnation with a volatile organic solution or with an aqueous anionic, cationic or non-ionic emulsion of the ketene dimer and the acyl compound, followed by heating the paper to develop the sizing properties of the ketene dimer-acyl compound combination.
Sized paper may be manufactured by use of the foregoing emulsion as beater additives. In such process the ketene dimer and the acyl compounds as single or as separate emulsions are added to an aqueous suspension of cellulose paper-making fibers, after which the suspension is sheeted to form a wet web and the web is heated to develop the sizing properties of the additives.
The ketene dimer and the acyl compound may be added as a single emulsion which may be cationic, anionic o-r non-ionic.
The cationic emulsions are self-substantive, and therefore when this type of emulsion is employed the fibrous suspension may be sheeted immediately thereafter.
The anionic emulsions are best employed in conjunction with a water-soluble cationic polymer. The polymer can be added first in sufficient amount to render the fibers cationic, or can be added after the anionic emulsion.
It is often advantageous to add the ketene dimer as two separate emulsions, which may be of the same or of opposite electrostatic sign. Where both emulsions are cationic or anionic, the process steps are as have been respectively described above. When they are of opposite electrostatic sign, they act as mutual retention aids.
The amount of sizing composition to be added in each instance is most conveniently found by trial because a given amount of the sizing composition produces somewhat difierent sizing depending upon the particular pulp employed, its pH, and the amount and identity of any cationic material present. In general, we have found that the most sizing per unit weight of the composition added occurs when the composition is added in the range of 0.2% to 0.4% based on the dry weight of the fibers, so that this range is preferred. However, valuable sizing results are obtained by the use of smaller amounts and by use of larger amounts, at least up to about 1%. The par ticular amount of the composition employed in any instance, however, is not a principal feature of the invention.
It is advantageous to maintain the paper at a temperature in the range of 200 F.-250 F. or higher, up to the temperature where the fibers become degraded, until the sizing properties of the ketene dimer-acyl combination have been developed at least to a substantial extent, because the development of substantial sizing during this heating is sure evidence that ultimate sizing of which the composition is capable of causing will develop on normal storage of the paper thereafter. In preferred embodiments of the present invention, this occurs within /z2 minutes when the paper is maintained in the above-stated temperature range. This is about sufiicient time for webs of ordinary basis weight to become substantially dry and corresponds to the'time required for paper to pass through the drying section of a typical paper-making machine.
The invention will be further illustrated by the examples, which are specific embodiments of the invention and are not to be construed as limitations thereon.
6 EXAMPLE 1 The following illustrates the effect of stearic acid as extender for hexadecyl ketene dimer. The agents are applied as organic solutions to preformed paper.
Solution A.-O.2 g. of hexadecyl ketene dimer is dissolved in 100 g. of benzene.
Solution B.0.1 g. of hexadecyl ketene dimer and 0.1 g. of stearic acid are dissolved in 100 g. of benzene.
A sheet of pure untreated cellulose paper (blotting paper) is immersed in solution A for two minutes, and a similar sheet is immersed in solution B for the same length of time. Both sheets are allowed to dry at room temperature for one hour. The sheet which was dipped in solution A is composed of cellulose fibers at least partly coated with hexadecyl ketene dimer. The sheet which was dipped in solution B is composed of cellulose fibers at least partly coated with a mixture consisting of hexadecyl ketene dimer and stearic acid in 1:1 weight ratio. The sheets are then heated at 230 F. for /2 hour to develop the ultimate sizing properties of the agents therein.
Sheet A contains about 0.2% by weight of hexadecyl ketene dimer and sheet B about 0.1% by weight each of hexadecyl ketene dimer and of stearic acid.
Both sheets possess substantially equal resistance to penetration by 20% aqueous lactic acid solution. The stearic acid in sheet B consequently acted as extender for the ketene dimer.
EXAMPLE 2 The following illustrates the comparative effect of several acidic, hydrophobic substantially water-insoluble, substantially straight-chain acyl compounds as accelerators of the development of the water-resistance imparted by paper-sizing ketene dimers. The agents are applied as non-ionic emulsions to preformed paper.
A series of emulsions is prepared as'follows. To 200 g. of Water at C. is added 2 g. of the condensation product of 10 mols of ethylene oxide with 1 mol of p-octylphenol (Triton X). The solution is agitated in a Waring Blender running at top speed, and there is slowly run in 15 g. of molten (80 C.) sizing composition, shown in the table below. After 30' seconds of agitation, 20 g. of the resulting emulsions are removed and are diluted to 0.27% size concentration by addition to 480 g. of cold water.
Weighed sheets of untreated cellulose absorbent paper (blotting paper) are immersed in the respective emulsions for 2 minutes, after which the sheets are removed. Excess liquid is removed by pressing the paper between similar damp paper. The sheets are reweighed. They contain 0.20% of size based on the dry weight of the fibers.
The sheets are dried by two passes of one minute each over a laboratory drum drier having a surface temperature of 230 F. From prior experience it is known that this drying does not develop more than a fraction of the sizing properties of hexadecyl ketene dimer, in the absence of an accelerator.
The sizing imparted by the emulsions was determined by the Cobb test, wherein the sheets are weighed, contacted on one side with 20% aqueous lactic acid as test fluid at 20 C. for 15 minutes, and reweighed. Sizing is reported as the grams of lactic acid solution which are absorbed per 25 cm? of paper surface.
1 HKD =hexadecyl ketene dimer.
2 Size to accelerator.
= Based on dry weight of the paper. 4 Paper was saturated with water.
The results show that the presence of the acyl compounds (stearic acid, stearic anhydride and stearamide) causes a major acceleration in the rate at which papersizing ketene dimers develop their sizing properties.
EXAMPLE 3 The following illustrates the manufacture of sized paper in similar manner using a different non-ionic emulsifying agent and an additional acyl compound.
A series of four emulsions is prepared by adding in each instance 15 g. of a molten (80 C.95 C.) sizing composition as shown in the table below to 200 cc. of water at 80 C. containing 1 ml. of polyoxyethylene sorbitol hexaoleate (a non-ionic emulsying agent manufactured by Atlas Chemicals Industries) in a Waring Blender operating at full speed. After one minute the resulting emulsions are diluted to 0.42% solids by addition of water at about C.
Four sheets of untreated cellulose paper (blotting paper) are weighed, soaked in the respective emulsions for five minutes, and removed. Excess emulsion is taken up by placing the sheets between blotting paper previously damped with water.
The sheets are reweighed and are found in each instance to contain 0.30% of sizing composition based on the dry weight of the fibers.
The sheets are dried by one pass of one minute over a laboratory drum drier having a surface temperature of 230 F.
Sizing is determined by the Cobb test, as described above, except that water is used as the test fluid.
To 100 g. of a 3% by weight hot (80 C.) aqueous solution of a water-soluble cationic starch in a Waring Blendor running at top speed is slowly added first 0.15 g. of sodium lignosulfonate and then 10.0 g. of molten (80 C.) hexadecyl ketene dimer. After 60 seconds the resulting emulsion is rapidly cooled by dilution to 1% with cold water.
The procedure is repeated twice, in the first instance 25% (2.25 g.) of the ketene dimer being replaced by myristic acid and in the second instance the same amount of the ketene dimer being replaced with stearic acid.
Sized paper is prepared by use of these emulsions by forming an aqueous suspension of a 30:70 bleached hardwood: bleached softwood kraft pulp at a consistency of 0.6% and a pH of 7. Aliquots are taken from this suspension and to each is respectively added sufiicient of the foregoing emulsions to provide 0.12% of sizing composition solids (hexadecyl ketene dimer plus any fatty acid added) on the dry weight of the fibers. There is then added suificient of an aqueous solution of cationic starch to provide 0.4% of cationic starch based on the dry weight of the fibers. The pH of the aliquots is adjusted to 6.3 and the suspensions are sheeted to form handsheets at a basis weight of 100 lbs. (25" x "/500 ream).
The handsheets are then dried by two passes of 1 minute each over a laboratory drum drier having a surface temperature of 230 F. From previous experience it is known that this drying is insufiicient in the absence of accelerator to develop more than a small fraction of the ultimate sizing of the hexadecyl ketene dimer.
The sizing of the resulting handsheets is determined by the lactic acid drop test, wherein drops of blue-tinted 20% aqueous lactic acid solution are applied to the paper at 20 C. Sizing is reported as the average time required for the drops to be absorbed by the paper.
Results are as follows:
Sizing Composition 1 HKD =hexadecyl ketene dimer. Of size to accelerator. Based on dry weight of paper.
b Percent hexadecyl ketene dimer in sheet, based on dry weight of ers. 2 Percent accelerator in sheet, based on dry weight of fibers.
The results show that replacement of ,6, of the ketene dimer with an acyl compound causes a major acceleration in the development of sizing.
EXAMPLE 4 The following shows the comparative effect of two different higher fatty acids as accelerators for hexadecyl ketene dimer as paper size. The following also illustrates the manufacture of sized paper by use of these agents employed as beater additives in aqueous cationic emulsion state.
The results show that in general longer chain acyl compounds are better accelerators than shorter chain acyl compounds.
- EXAMPLE 5 The following illustrates the effect of the acyl compounds both as accelerators and extenders of the sizing action of paper-sizing ketene dimers.
A series of emulsions is prepared by the method of Example 4. In the series, the ketene dimer is replaced by successively larger increments of stearic acid, but in each instance the total weight of the sizing composition added (ketene dimer plus stearic acid) is constant.
Sized handsheets are prepared by the standard test method of Example 4. One set of handsheets is given a short cure (2 minutes at 230 F.) to simulate commercial machine drying. The second set of thandsheets is given a long cure /2 hour at 223 F.) to develop substantially all the sizing which the composition is capable of imparting. The sizing of the sheets is determined by use of 20% aqueous lactic acid solution, applied by penescope at a temperature of F. under a head of 12".
Results are as follows:
Sizing Composition 1 Sizing (Seconds) Run No.
HKDzSA Percent Percent Percent Percent Short Cure Long Cure Wt. Ratio 111(1) 2 SA 2 HKD+SA 3 HKD+SA 2 100:0 0. 20 None None None 900 9, 600 95:5 0. 19 0.01 5. 5 0. 20 3,000 9, 600 90:10 0. l8 0. 02 ll. 0. 20 5, 600 10, 400 75:25 0. 15 0. 33. 3 0. 20 7. 400 11, 450 50:50 0. l0 0. 100. 0 0. 20 7, 850 9, 650 30:70 0. 06 0. 14 233. 3 0. 20 None None 1 HKD=hexadeeyl ketene dimer; SA=stearic acid. 2 Based on dry weight of the fibers. 3 Based on weight of the hexadecyl ketene dimer present.
The results are shown graphically in the drawing, curve powder forms an anionic emulsion when 10 g. is slowly A being a graph of the results obtained with the short cure and curve B being a graph of the results obtained with the long cure.
From other tests it is known that prolongation of cure does not necessarily cause continued increase in the waterrepellance imparted by the sizing composition. These tests have shown that when large amounts of extender are present based on the weight of the ketene dimer, sizing values slowly decrease when the paper is held at curing temperatures for comparatively long periods of time. The optimum cure time can be readily found by laboratory trial, and our own tests suggest that curing the paper for half an hour at 105 C. will generally result in development of maximum sizing values.
EXAMPLE 6 The following illustrates the preparation of a homogeneous composition according to the present invention consisting essentially of a paper-sizing ketene dimer and a fatty acid as accelerator therefor.
A melt of hexadecyl ketene dimer and stearic acid in l:1 /2 Weight ratio having a temperature of 90 C. is flowed upon a rotating drum chiller provided with a doctor blade. The surface temperature of the chiller is 30 C. Homogeneous crisp flakes are obtained.
The flakes are powdered by passage through a roller crusher. The resulting powder is free-flowing.
Both the flakes and the powder emulsify readily when slowly poured into intensively-agitated water at 90 C. which contains an emulsifying agent.
EXAMPLE 7 The foregoing procedure is repeated except that stearic anhydride is employed in place of the stearic acid. A similar composition is obtained.
EXAMPLE 8 The procedure of Example 6 is repeated except that stearamide is employed in place of the stearic acid and the temperature of the melt is about 100 C. A similar composition is obtained.
EXAMPLE 9 The following illustrates the preparation of an ionic self-dispersible composition according to the present invention.
To 100 g. of the homogeneous free-flowing powdery blend of hexadecyl ketene dimer and stearic acid (1: 1 /2 weight ratio) of Example 6 is added 1.5 g. of sodium lignosulfonate and 33 g. of a water-soluble cationic starch, and the mixture is ball-milled for a few minutes. The resulting powder emulsifies when 10 g. of the powder is slowly added with intensive agitation to 100 cc. of water at 90 C.
EXAMPLE 10 The following illustrates the preparation of a dry blend of a paper sizing which forms an anionic emulsion.
To 100 g. of the powdered hexadecyl ketene dimerstearic acid blend of Example 6 is added 1.0 g. of sodium bicarbonate. The mixture is ball-milled. The resulting added with intensive agitation to 100 cc. of water at EXAMPLE 11 To an aqueous suspension of beaten cellulose papermaking fibers at 0.6% consistency is added 0.5% based on the dry weight of the fibers, of a cationic polyamidopolyamine-epichlorohydrin wet strength resin of Keim 7 U8. Patent No. 2,926,154 as a 1% aqueous solution, followed by sufficient of the emulsion described above to provide 0.3% of sizing solids based on the dry weight of the fibers. The size is precipitated on the fibers by the adsorbed cationic resin and yields about as well-sized paper as is obtained by a corresponding size prepared by use of an equal amount of the hexadecyl ketene dimer alone EXAMPLE 12 The following illustrates a preferred method for the manufacture of sized paper according to the present invention by addition of a cationic cellulose-substantive hexadecyl ketene dimer-stearic acid emulsion to beater pulp, the amount of stearic acid being sufficient to'provide excellent acceleration of cure and extension of the effect of the ketene dimer.
An aqueous suspension of beaten cellulose papermaking fibers is prepared at 0.6% consistency and at pH 7 and to this is added 0.2%, based on the dry weight of the fibers of a 50:50 by weight ratio of the diluted hexadeeyl ketene dimer:steric acid cationic emulsion prepared as described in Example 9 above.
The suspension is stirred briefly to permit adsorption of the size by the fibers to take place, after which the suspension is sheeted to form' handsheets. The handsheets are dried for two minutes at 230 F. and are well sized.
EXAMPLE 13 The following illustrates another preferred method for the manufacture of sized paper. In this method the ketene dimer and the acyl compound are added to beater pulp as separate ionic emulsions of opposite electrostatic sign.
An aqueous cationic emulsion of hexadecyl ketene dimer is prepared by the method of Example 4. An aqueous anionic emulsion of stearic acid is prepared by intensively agitating 142 g. of stearic acid with 1500 cc. of water at 90 C. containing 0.4 g. of sodium hydroxide.
To an aqueous suspension of cellulose paper-making fibers at pH 7 is added 0.15% of the cationic ketene dimer emulsion (emulsion solids based on the dry weight of the fibers) followed by 0.1% of the stearic acid emulsion, on the same basis.
1 1 The paper is made into handsheets by customary procedure and is dried for 2 minutes at 230 F. Well-sized paper is obtained.
EXAMPLE 14 The effectiveness of hexadecanoyl chloride for papersizing ketene dimers is illustrated by the following:
The procedure of Example 1 is repeated except that the stearic acid used in Example 1 is replaced by a like amount of hexadecyl aldehyde and chloroform is used as solvent in place of the benzene in Example 1. Similar results are obtained.
1. A composition consisting essentially of a papersizing ketene dimer and an effective extending amount in excess of about based on the Weight thereof, of a hydrophobic substantially water-insoluble saturated substantially straight-chain acyl compound as extender therefor.
2. A composition according to claim 1 wherein the acyl compound is stearic acid.
3. A composition according to claim 1 wherein the acyl compound is stearamide.
4. A composition according to claim 1 wherein the acyl compound is distearic anhydride.
5. A composition consisting essentially of hexadecyl ketene dimer and an effective amount, between about 25% and 100%, based on the weight thereof, of stearic acid as exterior therefor.
6. A composition essentially composed of a paper-sizing ketene dimer and an effective amount within the range of from 10% to about 200%, based on the weight thereof, of a hydrophobic substantially water-insoluble saturated substantially straight-chain acyl compound selected from the group consisting of higherfatty acids and their anhydrides, chlorides, amides and aldehydes as ex tender therefor, and an emulsifying agent for said composition.
7. A composition according to claim 6 wherein the acyl compound is stearic acid and the emulsifying agent is an anionic emulsifying agent.
8. A fluid aqueous emulsion of a composition according to claim 6.
9. Paper composed of cellulose fibers sized by a uniformly distributed reacted content of a paper-sizing ketene dimer and by an effective uniformly distributed unreaoted content, within the range of from. 10% to about 200% of the weight of said ketene dimer, of a hydropho bic substantially water-insoluble saturated substantially straight-chain acyl compound selected from the group consisting of higher fatty acids and their anhydrides, chlorides, amides and aldehydes as extender therefor.
10. Paper composed of cellulose fibers sized by a uniformly distributed reacted content of hexadecyl ketene dimer and by an effective uniformly distributed unreacted content, within the range of from 10% to about 200% of the weight of said ketene dimer, of stearic acid as extender therefor.
11. In the manufacture of sized paper, wherein a paper-sizing ketene dimer is deposited on cellulose fibers as sizing agent and said fibers are heated at a temperature between about 200 F.250 F., the improvement which comprises depositing on said fibers along With said ketene dimer an effective extending amount, in excess of about 10% based on the weight of said ketene dimer, of a hydrophobic saturated substantially water-insoluble substantially straight-chain acyl compound as extender therefor.
12. In the manufacture of sized paper, wherein an aqueous emulsion of a paper-sizing ketene dimer is added as sizing agent to an aqueous suspension of cellulose paper-making fibers, said fibers are sheeted to form a water-laid web, and said web containing said ketene dimer is dried at a temperature in the range of about 200 F.- 250 F., the improvement which comprises adding to said suspension an effective amount within the range of from 10% to about 200%, based on the weight of said ketene dimer, of a hydrophobic substantially water-insoluble saturated substantially straight-chain acyl compound selected from the group consisting of higher fatty acids and their anhydrides, chlorides, amides and aldehydes in aqueous emulsion state as extended for said ketene dimer.
13. A process according to claim 12 wherein said ketene dimer and said acyl compound are added as a single cellulose-substantive cationic emulsion.
14. A process according to claim 12, wherein said ketene dimer and said acyl compound are added as separate emulsions.
15. In the manufacture of sized paper wherein an aqueous suspension of paper-making cellulose fibers is formed, said fibers are rendered cationic, said fibers are sheeted to form a water-laid web, and said web is dried at a temperature between 200 F. and 250 F., the improvement which comprises adding to said suspension a small but effective amount'as sizing agent of an aqueous anionic emulsion of a mixture of a paper-sizing ketene dimer and an effective amount within the range of from 10% to about 200%, based on the weight of said ketene dimer, of a hydrophobic substantially water-insoluble saturated straight-chain acyl compound selected from the group consisting of higher fatty acids and their anhydrides, chlorides, amides and aldehydes as extender therefor.
16. A process according to claim 15, wherein the weight of said acyl compound is between about 25% and of the weight of said ketene dimer and the web is maintained at said drying temperature until at least half of the ultimate sizing of said ketene dimer has developed.
References Cited by the Examiner UNITED STATES PATENTS 2,901,371 8/1959 Arlt 106243 DONALL H. SYLVESTER, Primary Examiner.
S. L. BASHORE, Assistant Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 311,532 March 28, 1967 Russell Joseph Kulick et al.
It is certified that error appears in the above identified 7 patent and that said Letters Patent are hereby corrected as -show'n below:
Column 2, line 21, "of" should read on Column 3, line 47,
"ketent" should read ketene line 57, "along should read alone Column 10, line 52 "steric should read stearic Column 11, line 28, "exterior" should read extender Column 12, line 23, "extended" should read extender Signed and sealed this 7th day of April 1970.
Edward M. Fletcher, Jr.
Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.