United States Patent Office
`
`3,589,978
`Patented June 29, 1971
`
`1
`
`3,589,978
`PROCESS OF MAKING WATER REPELLENT PAPER
`USING A FATTY POLYISOCYANATE AND A
`CATIONIC GUM ETHER AND PRODUCT
`THEREFROM
`Marwan R. Kamal, Dhahran, Saudi Arabia, and James L.
`Keen, New Brighton, Minn., assignors to General Mills,
`Inc.
`No Drawing. Filed Sept. 29, 1967, Ser. No. 671,567
`Int. Cl. D21d 3/00
`U.S. Cl. 162-158
`8 Claims
`
`
`
`ABSTRACT OF THE DISCLOSURE
`
`In a process of making water repellent paper, including
`the addition to the aqueous dispersion of cellulosic fibers
`of (1) an organic polyisocyanate of the formula
`
`R--[(CH2)yNCO]x
`where y is 0 or 1, x is an integer of 2 to about 4 and R
`is the hydrocarbon group of polymerized fat acids derived
`from fat acids of 16 to 22 carbon atoms such as dimeryl
`isocyanate and (2) a quaternary ammonium polygalac-
`tomannan gum ether cationic retention agent, for example
`quaternary ammonium gum ether.
`
`2
`nates. This method of preparation can be conveniently
`illustrated by the following equations (using a dimeric fat
`acid as an example)
`3HOOC—D—CO OH + 2P C13 §>
`3ClOC—-D—COCl + 2H3PO3
`C10 C—D—COCI + 2NaN3 —-> N30 C—-D—CON3 + 2NaCl
`NsOC—D——OONs —b OCN——D—NCO -i-2N2
`A
`
`The polyisocyanates where y is 1 are prepared by con-
`verting the polymeric fat acids to the corresponding poly-
`nitriles and then hydrogenating the polynitriles in the
`presence of ammonia and a catalyst such as Raney nickel
`to form polyamines. The polyamines are then reacted with
`phosgene to give the polyisocyanates. This method of
`preparation can be conveniently illustrated by the follow-
`ing equations (using a dimeric fat acid as an example):
`HOOC—D—COOH + 2NHs —> NC—D—CN + 4HzO
`NH
`NC——D—CN + 4H3 —;> H;N-H2C——D—-CHgNHg
`Catalyst
`H2NCH2—D-CH2NH2 + 20001;
`-——>
`OCNCH2—-D——CH2NCO + 4HC1
`
`5
`
`10
`
`15
`
`20
`
`25
`
`D in the foregoing two series of equations is the divalent
`hydrocarbon radical of dimerized fat acids and contains
`30 to 42 carbon atoms.
`
`The present invention relates to a process of preparing
`paper from cellulosic fibers and to the resulting products.
`More particularly, it relates to such a process wherein
`certain organic polyisocyanates and cationic retention aids
`are added to the cellulosic fibers prior to the formation of
`sheets from such fibers. The resulting paper has improved
`properties, especially water repellency and wet. strength.
`It was recently found that polyisocyanates Cl6I‘lV6d from
`polymeric fat acids could be used to treat ‘already formed
`paper and fabrics to give such materials improved water
`repellency and/ or softness. While this treatment 1s.eflec-
`tive, it does involve a separate and additional step in the
`manufacturing process—i.e. the dipping, spraying or the
`like of a solution or emulsion of the polyisocyanate onto
`the already formed paper or ‘fabric. Since the polyisocya-
`nates derived from polymeric fat acids are reasonably
`stable in the presence of water, it was felt that the same_
`could be added to aqueous dispersions of the cellulosic
`fibers prior to the -formation of the same into sheets—i.e.,
`paper, non-woven fabrics. However, when this was at-
`tempted little,
`if any, water repellency or sizing was
`obtained.
`‘
`We have now discovered that the water repellency and
`other properties of articles formed from aqueous disper-
`sions of cellulosic fibers can be significantly improved If
`an organic polyisocyanate derived from polymeric fat
`acids and a cationic retention aid are added to such dis-
`persions prior to the formation step. Our invention makes
`it possible to produce paper and other articles having in—
`creased water repellency and wet strength without having
`to treat the already formed articles in a separate step.
`The polyisocyanates useful in our invention have the
`following idealized structural formula:
`
`l:R:I—T—||:-(CH2)yNCO]x
`where y is 0 or 1, x is an integer of 2 to about 4 and R is
`the hydrocarbon group of polymerized fat acids derived
`from fat acids of 16 to 22 carbon atoms. The polyisocya-
`nates of the above formula wherein y is 0 are prepared
`by converting the polymeric fat acids to the corresponding
`polymeric fat acid chlorides, reacting the acid chlorides
`with a metal azide to form the polymeric acyl azides and
`then heating the acyl azides to produce the polyisocya-
`
`30
`
`35
`
`40
`
`50
`
`60
`
`65
`
`70
`
`The starting polymerized fat acids are prepared by
`polymerizing ethylenically unsaturated monobasic carbox-
`ylic acids having 16 to 22 carbon atoms or the lower
`alkyl esters thereof. The preferred acids are the mono
`and polyolefinically unsaturated 18 carbon atom acids.
`Representative octadecenoic acids are 4-octadecenoic, 5-
`octadecenoic, 6-octadecenoic (petroselinic), 7-octadece-
`noic, 8-octadecenoic, cis-9-octadecenoic (oleic),
`trans-9-
`octadecenoic (elaidic),
`ll-octadecenoic (vaccenic), 12-
`octadecenoic and the like. Representative octadecadienoic
`acids are 9,12-octadecadienoic (linoleic), 9,ll-octadeca-
`dienoic, 10,12-octadecadienoic, 12,15-octadecadienoic and
`the like. Representative octadecatrienoie acids are 9,12,15-
`octadecatrienoic
`(linolenic),
`6,9,l2—0ctadecatrie11oic,
`9,l1,l3-octadecatrienoic (eleostearic), 10,12,14-octadeca-
`trienoic (pseudoeleostearic) and the like. A representative
`18 carbon atom acid having more than three double -bonds
`is moroctic acid which is indicated to be 4,8,l2,l5-octa-
`decatetraienoic acid. Representative of the less preferred
`(not as readily available commercially) acids are: 7-
`hexadecenoic, 9-hexadecenoic (palmitoleic), 9-eicosenoic
`(gadoleic), 11 - eicosenoic, 6,10,14 - hexadecatrienoic
`(hiragonic), 4,8,12,16 - eicosatetraenoic, 4,8,12,15,18-
`eicosapentanoic (timmodonic), 13-docosenoic (erucic),
`11—docosenoic (cetoliec), and the like.
`The ethylenically unsaturated acids can be polymerized
`using known catalytic or non-catalytic polymerization
`techniques. With the use of heat alone, the mono-olefinic
`acids (or the esters thereof) are polymerized at a very
`slow rate while the polyolefinic acids (or the esters there-
`of) are polymerized at a reasonable rate. If the double
`bonds of the polyolefinic acids are in conjugated positions,
`the polymerization is more rapid than when they are in
`the non-conjugated positions. Clay catalysts are commonly
`used_ to accelerate the dimerization of the unsaturated
`acids. Lower temperatures are generally used when a
`catalyst is employed.
`The polymerization of the described ethylenically un-
`saturated acids yields relatively complex products which
`usually contain a predominant portion of dimerized acids,
`a smaller quantity of trimerized and higher polymeric
`acids and some residual monomers. The 32 to 44 carbon
`atom dimerized acids can be obtained in reasonably high
`purity from the polymerization products by vacuum distil-
`lation at low pressures, solvent extraction or other known
`
`UNL 1058
`
`1
`
`

`
`3,589,978
`
`3
`separation procedures. The polymerization product varies
`somewhat depending on the starting fat acid or mixture
`thereof and the polymerization technique employed-i.e.,
`thermal, catalytic, particular catalyst, conditions of pres-
`sure, temperature etc. Likewise, the nature of the dimer-
`ized acids separated from the polymerization product also
`depends somewhat on these factors although such acids
`are functionally similar.
`Attempts have been made to fully delineate the struc-
`tures of dimerized acids prepared from ethylenically un-
`saturated acids. These studies have been based largely on
`the products obtained by polymerizing linoleic acid or
`the methyl esters thereof or starting materials rich in
`linoleic acid or methyl linoleate. Paschke and Wheeler,
`in a study relating principally to the thermal polymeriza-
`tion of normal methyl linoleate, stated that at least two
`main products had been identified by others as resutling
`from such polymerization:
`
`5
`
`10
`
`CH3(CHz)5—CH-'CH—CH-CH=CH-(CH2)7—C O 0 CH3
`/
`\
`CE3(CH2)5~CH
`CH—-(CH2)7CO0CH3
`
`20
`
`and
`
`oH=cé
`
`CH3(CH2)4-CH—CH—OH2—-CH=CH—(CH2)7CO 0 CH3
`
`25
`
`CH3(CH2)5——C:E[
`
`/CH-(CH-2)7COOCH3
`CH=CH
`
`4
`materials rich. in octadecadienoic acids and that the self-
`polymerization of said acid could be depicted as follows:
`
`R—C=C—C<C—C=C—-R’
`R—-C=C-C=C—C=C—R’
`C—C=C—R’
`+
`/C=C
`R-—C=C—C=C—C=C—R’ ?-—> R—C\
`
`However, the author stated that such a product had not
`been isolated and that a second reaction probably takes
`place which could yield a diacid of the structure
`
`R-C=C7C—c
`R—C\ 0:0
`
`\/\\
`
`C—C-{R'C-R’
`
`o-o/
`
`Ault et al. gave a possible structure for the dimer of
`methyl oz-eleostearate, an ester of an octadecatrienoic
`acid, as follows:
`
`CH—CH=CE—OH=CH(CHz)7CO 0 CH3
`/ \
`CH-CH=CH(0H2)7COO CH3
`CH
`
`CHa—(CEf2)s—C
`l
`CH3-—( CH2)3—CH
`\C
`they also postulated that the structure could
`However,
`in fact be more complicated. Thus it was postulated that
`further cyclic rings were formed due to the high unsat-
`uration giving a compound having the following proposed
`structure:
`
`m\\_
`
`Their experimental work then indicated the latter struc-
`ture predominated in the thermal polymerization product
`(The Journal of the American Oil Chemists Society, vol.
`XXVI, No. 6, June 1949, pages 278-83). Moore theorized
`(using the Diels-Alder mechanism) that the polymeriza-
`tion of linoleic acid would yield a variety of 36 carbon
`atom acids of high structural similarity (Paint, Oil & Chem-
`ical Review, Jan. 4, 1951, pages 13-15, 26-29). Thus
`it was generalized that a portion of normal linoleic acid
`having the structure
`
`CH3'( CH2 ) 4CI-I= CHCH2CH= CH (CH2) -;COOI-I
`
`(depicted for convenience as R—C=C—C—C=C—R’)
`would be conjugated during the polymerization to the
`9,11 acid;
`
`CH3(CH2)4CH2CH=CHCH'=CH(CH2)7COOH
`
`(depicted for convenience as R—C—C=C—-C=C—R’)
`It was then set forth that these acids could polymerize as
`follows:
`
`/C=C\
`
`C—R'
`:. R—C—C
`R}C_CfiC_C=C_R,
`
`R-0-0:0-C=C—R’
`+
`R—C=C—C—C=C—R’
`01'
`R—-C-C=C-C=C—R’
`
`+
`R-C—-C=C—C=C—R’
`01‘
`
`0:0
`
`/
`C—R’
`—-» R—C—C
`\
`R—C—C—-CéC=C—R’
`
`\
`
`R—C-C=C—-C=C—-R’
`+
`R—C=C——C-C=C—R’
`
`/o=o\
`:» R-C—C\
`/C—R’
`R—C=G-—C—C—C—R’
`
`O1‘
`
`R—C—C=C—C=O-R’
`+
`R—C—~C=C—-—C=C—R’
`
`/c=o\
`C-R’
`-» R—C—C
`/
`\
`R—C—C=C—C—C—R’
`
`Moore further indicated that the 9, 12-linoleic acid could
`also conjugate to the 10,12 acid and that this acid could
`self-polymerize or polymerize with the 9,12 or 9,11 acids.
`It was stated that the polymerizations could be “head-to-
`tail” as well as “head—to-head” as depicted above. Moore
`further stated that
`in many instances octadecatrienoic
`acids are present in many of the naturally occurring raw
`
`CH=CH
`
`or
`\
`
`CH(CH2)7‘C0O CH:
`|
`OH
`/ \ /CH—6H(CH2)7COOCH3
`cH.(oH2)a-on
`CH
`CH.(CH2)a—(|:H
`CH
`\ %CH
`
`(Industrial and Engineering Chemistry, vol. 34, No. 9,
`September 1942, pages 1120-3.)
`Other information obtained is in essential agreement
`with the above studies. Thus analysis of dimerized acids
`prepared from linoleic acid rich starting materials using
`heat alone or heat plus a catalyst, such as an acid or
`alkaline clay, shows that the product contains structurally
`similar acids having monocyclic tetrasubstituted cyclo-
`hexene ring structures as well as acids with two and three
`rings, such additional rings generally being fused to the
`six carbon atom ring. Additionally,
`the clay catalyzed
`dimerized acids have been shown to contain some aro-
`matic rings according to ultraviolet and infrared spec-
`troscopy. These aromatic rings are believed to be formed
`by hydrogen transfer (by catalytic action of clay) from
`the substituted cyclohexene ri11g to form a substituted ben-
`zene ring. Such acids are believed to comprise less than
`about 20% by Weight of the dimerized fat acid. Polym-
`erization of pure oleic acid using a clay catalyst has been
`shown to yield a mixture of dimerized fat acids of which
`approximately 25-30% by weight have a tetrasubstituted
`cyclohexane ring with the remainder being non-cyclic.
`However, when mixtures of oleic and linoleic acids (such
`as from tall oil) are polymerized, the resulting dimerized
`fat acid contains little if any dimer having a non-cyclic
`structure.
`the polymerization of the
`that
`It
`is thus apparent
`ethylenically unsaturated acids yields complex products.
`The dimer fraction thereof, generally consisting of a
`mixture of acids, can be assigned the formula:
`HOOC-—D—-COOH
`
`where D is a divalent hydrocarbon group containing 30
`to 42 carbon atoms. It is also apparent that said divalent
`hydrocarbon group is complex. However, from the noted
`studies and other information obtained, it can be seen
`that a mixture of acids normally results from the polym-
`
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`
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`
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`
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`
`2
`
`

`
`3,589,978
`
`5
`erization and subsequent fractionation and these acids
`have structural and functional similarities. Thus such
`mixture of acids contains a significant proportion of acids
`having a six carbon atom ring (about 25% or more even
`when the starting fat acid is a mono-olefinically unsat-
`urated acid such as oleic). The remaining carbon atoms
`in the divalent hydrocarbon group of such ring containing
`acids are then divided between divalent and monovalent
`radicals which may be saturated or ethylenically unsat-
`urated. Such radicals may form one or more additional
`cyclic structures which are generally fused to the first
`six membered ring. Such dimeric acids may be considered
`as having a theoretical
`idealized, general formula as
`follows:
`-
`
`RIII
`
`R'-COOH
`
`XX
`
`RIII/ RIl_COOH
`
`where R’ and R” are divalent hydrocarbon radicals, R"’
`and R”” are monovalent hydrocarbon radicals and the
`sum of the carbon atoms in R'—R”” is 24-36. The ring
`contains one double bond. It is also understood that the
`R’—R”" radicals may form one or more additional cyclic
`structures which are generally fused to the first ring. It
`is further understood that the ring or rings may be sat-
`urated such as where the dimer acids are hydrogenated
`under conditions which convert the unsaturated acids to
`the corresponding saturated compounds.
`As a practical matter, the polymeric fat acids are pref-
`erably prepared by the polymerization of mixtures of
`acids (or the simple aliphatic alcohol esters—i.e.,
`the
`methyl esters) derived from the naturally occurring dry-
`ing and semi-drying oils or- similar materials. Suitable
`drying or semi-drying oils include soybean, linseed, tung,
`perilla, oiticia, cottonseed, corn, sunflower, dehydrated
`castor oil and the like. Also, the most readily available
`acid is linoleic or mixtures of the same with oleic, lino-
`lenic -and the like. Thus, it is preferred to use as the start-
`ing materials, mixtures which are rich in linoleic acid. An
`especially preferred material is the mixture of acids ob-
`tained from tall oil which mixture is composed of approxi-
`mately 40-45% linoleic and 50-55% oleic. It is also
`preferred to carry out the polymerization in the presence
`bf a clay. Partial analysis of a relatively pure dimer
`_ fraction (98.5% dimer) obtained from the product pre-
`pared by polymerizing the tall oil fatty acids in the pres-
`ence of 10% by weight of an alkaline montmorillonite
`clay at a temperature of 230° C. and a pressure of 140
`p.s.i. for five hours showed that it was a mixture of C36
`acids, one significant component being
`HO O C ( CH2)?-CH
`HO
`I!no
`
`(EH—CH2—CH=CH(CH2)7C O OH
`OH—(CHz)4CH3
`
`at
`((|l3H2)4
`CH3
`
`Hydrogenation of such mixture of acids using palladium
`catalyst yielded the corresponding saturated acids, one sig-
`nificant component thereof being
`HO O C(CH2)5~CH
`
`(|}H——(CH2)1uCOOH
`CH—(CH2)4CH3
`
`H|CH
`HCE
`
`pfi
`(('7H2)4
`CH3
`
`Such mixture of saturated dimerized fat acids was used
`in the preparation of the dimeryl isocyanate employed
`in the example of the invention to follow.
`The preferred cationic retention aids are that quater-
`nary ammonium polygalactornannan gum ethers which
`
`6
`are prepared by reacting the gums with reactive quater-
`nary ammonium compounds. The starting po1ygalacto-
`mannan gums are well known and commercially avail-
`able. The most common of these =are guar gum and locust
`bean gum. The starting quaternary ammonium compounds
`particularly suitable may be defined by the following for-
`mula:
`
`R1
`l
`R4—¥“'—R2 Z‘
`Ra
`
`where R1, R2 and R3 are selected from the group consist-
`ing of alkyl, substituted alkyl, alkene, aryl and substituted
`aryl groups, Z— is an anion and R4 is selected from the
`group consisting of epoxyalkyl and halohydrin groups.
`Illustrative of the anion Z‘ and Cl‘, Br‘, I“ and HSO4“.
`The group R4 may be further illustrated by the formulae
`below:
`
`Cl
`
`10
`
`15
`
`20
`
`(1) Epoxyalkyl:
`
`25
`
`(2) Halohydrin:
`
`H20
`
`C-R5—
`
`\O/
`
`XH2C——(|3~R5—
`OH
`
`where X is a halogen atom and R5 is a divalent alkylene
`radical having from 1
`to 3 carbon atoms. R5 may be
`straight or branched chain. Illustrative thereof are
`—0H,—, —CH2CH2—, —CHgCHzCHg— and ——CHgCH—-
`([3113
`If R1, R2 and R3 are the same, they each should pref-
`erably contain not -more than 4 carbon atoms. If they are
`not the same and one of such groups contains up to 18 car-
`bon atoms, then the remaining two groups should prefer-
`ably be methyl or ethyl. If two of such groups are joined
`to form a ring, then the third group should preferably
`be methyl or ethyl. Thus,
`the total number of carbon
`atoms in R1, R2 and R3 should preferably not exceed 22
`carbon atoms and may be as low as 3 carbon atoms.
`Quaternary ammonium compounds of the type which
`may be employed are commercially available. Illustrative
`of these commercially available compounds are 2,3-epoxy-
`propyl
`trimethylammonium chloride and 3-chloro-2-hy-
`droxypropyl trimethylammonium chloride. The quaternary
`ammonium compounds may be prepared by reacting a ter-
`tiary amine or tertiary amine salt with an epihalohydrin.
`Tertiary amines having the groups R1, R2 and R3 defined
`above may be employed. The epihalohydrin employed is
`one providing the group R4 defined above. If a tertiary
`amine is used, R4 is an epoxyalkyl group. If a tertiary
`amine salt is employed, R4 is a halohydrin group as de-
`fined above. Illustrative tertiary amine salts are the salts
`prepared by treating a tertiary amine with hydrochloric
`acid, sulfuric acid or phosphoric acid.
`The preferred tertiary amines are those possessing at
`least two methyl groups (i.e. R1 and R2) attached direct-
`ly to the nitrogen atom because of their greater reactivity
`which is maintained even when the third group (i.e. R3)
`contains 18 carbon atoms as in dimethylstearyl amine.
`Other representative tertiary amines are dimethylbenzcne
`amine, dimethyldodecyl amine, dimethyldecyl amine, di-
`ethylstearyl amine, diethyldodecyl amine, diethylbenzene
`amine, triethyl amine, tripropyl amine, tributyl amine, N-
`ethyl and N-methyl morpholine, N-ethyl and N-methyl
`piperidine and methyldiallyl amine.
`The quaternary ammonium compounds may be pre-
`pared by simply mixing equimolar quantities of the epi-
`chlorohydrin and tertiary amine (or the salt thereof) in
`an aqueous system and allowing the reaction to proceed
`preferably with agitation until formation of the product
`is complete. VVhen employing the salts, best results are
`obtained if the pH of the aqueous system is above 8 and
`
`30
`
`35
`
`40
`
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`
`50
`
`60
`
`65
`
`70
`
`75
`
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`
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`
`8,589,978
`
`7
`preferably between 9 and 10. The resultant addition prod-
`uct is then recovered by vacuum distillation of the unre-
`acted epihalohydrin and amine.
`For illustration,
`the reaction of epichlorohydrin and
`trimethylamine and also epichlorohydrin and trimethyl-
`amine hydrochloride may be shown by the following equa-
`tions:
`O
`(1)
`/ \
`(CH3)3N + C1CH2CH——CH2 —-
`
`O
`/ \
`H2 0-: CH--CH2—N+(CHa) 301‘
`
`O
`(2)
`/ \
`(CI-I:4)N-H01 + C1CH2CH-—-—CHz ?>
`
`.
`
`OH
`I
`ClCH2CHCH2—N+(CH3)aCl—
`
`In order to prepare the quaternary ammonium poly-
`galactomannan gum ethers,
`the above-described quater-
`nary ammonium compounds may be dissolved in a suit-
`able solvent such as water, dioxane or an alcohol and the
`gum added thereto. Any inert solvent may be employed.
`Among the suitable alcohols are isopropanol, methanol,
`ethanol and tertiary butanol. A strongly alkaline catalyst
`is generally employed to -promote the reaction. The reac-
`tion occurs at room temperature; however, heat and in-
`creased amounts of catalyst increase,
`the reaction rate.
`In general, temperatures of at least 30° C. up to 60° C.
`are preferably employed. The catalyst, -when employed,
`is preferably not used in excess of 0.1 mole per molar
`weight of anhydroglucose unit. Illustrative of the catalysts
`which are preferably employed are the alkali metal hy-
`droxides, alkaline earth hydroxides and quaternary am-
`monium -bases, such as sodium hydroxide,
`lithium hy-
`droxide, potassium hydroxide, calcium hydroxide, ammo-
`nium hydroxide and benzyltrimethylammonium hydrox-
`ide. After the etherification reaction, the catalyst may be
`left in the reaction product or neutralized with any suit-
`able acid such as acetic or hydrochloric.
`The quaternary ammonium compound is preferably
`employed in an amount of from 0.02 to 0.1 mole per
`molar weight of anhydroglucose unit; however, amounts
`from 0.01 to 0.2 mole are also useful. By varying the
`amount of quaternary com-pound, varying degrees of sub-
`stitution (D.S.) are provided.
`The preparation of the quaternary ammonium poly-
`galactomannan gum ethers is further described by the
`following illustrative examples.
`EXAMPLE A
`
`Into a Readco double-bladed mixer of one quart capac-
`ity Was added 100 grams of commercial guar flour. To
`this was added dropwise 100 mls. of water containing
`2 grams of sodium hydroxide and 7.6 grams (0.1 equiv-
`alent) 2,3-epoxypropyltrimethylammonium chloride. This
`aqueous solution swelled the guar to give a fluffy product
`that was easily kept
`in motion by the Readco Mixer.
`After the guar and aqueous solution were thoroughly
`mixed for 5 minutes, the jacket of the Readco was heated
`with water at 50-55 ° C. for a period of two hours. The
`reacted product was then removed, dried and finally
`ground to pass a 30 mesh screen. One-half of the dried
`product was washed with ‘methanol in an attempt to re-
`move any unreacted quaternary. Both fractions had the
`same nitrogen content indicating that the quaternary was
`attached to the guar by a chemical bond.
`EXAMPLES B-G
`
`Example A was essentially repeated using the same
`procedure and varying only the amount of quaternary
`ammonium compound. A series of products having de-
`grees of substitution (D.S.) of 0.0125, 0.025, 0.05, 0.075,
`0.15 and 0.20,
`respectively, were produced. The D.S.
`of the ether of Example A was 0.10.
`
`8
`- EXAMPLE H
`
`In the same manner as ‘Example A, the product was
`prepared employing 0.1 equivalent of 3-chloro-2-hydroxy-
`propyl trimethylammonium chloride.
`’
`EXAMPLE I
`
`Example A was essentially repeated using locust bean
`gum to yield an ether having a degree of substitution
`of 0.1.
`representative cationic retention aid which
`Another
`may be used in the present invention is polyethylene-
`imine.
`the polyisocyanate and the
`As indicated previously,
`cationic retention aid are added to the aqueous disper-
`sion of the cellulosic fibers prior to the formation of
`sheets therefrom. Such addition can take place in the
`beater or to the already beaten ‘or refined dispersion
`provided that the dispersion and the additives are reason-
`ably thoroughly mixed. Sheets are then formed from
`the dispersion using conventional techniques. In this re-
`spect the uniform dispersion of the pulp fiber containing
`the polyisocyanate and cationic retention aid is filtered
`through a screen which leaves a wet sheet on the screen.
`This sheet can then be dried to make paper, non-woven
`fabrics and the like. Any of the commercially available
`forming machines can be used including the Fourdrinier
`and cylinder machines. The wet sheets are ordinarily
`dried at temperatures of 200° F. to 250° F. to a moisture
`content of less than about 12% and preferably in the
`range of 6% to 9% by weight. Any conventional dry-
`ing technique can be used such as steam heated dryers.
`The cellulosic fibers can be any of those used in paper
`making, such as those commonly referred to as sulfite,
`soda, sulfate, and ground wood stock, or fibers derived
`from rag, cotton, bast, flax, and stem fibers such as straw,
`or from repulped broke. The concentration of the fibers
`in the aqueous dispersion is generally less than about 6%
`by weight and preferably in the range of 0.5 to 1.0%
`by weight. The polyisocyanate is added to the aqueous
`dispersion of cellulose fibers in an amount sufficient to
`increase the water repellency of the sheetsformed from
`such dispersion. Preferably,
`the polyisocyanate is used
`in an amount of about 0.05 to 2.5% by weight based
`on the dry weight of the fiber solids. The cationic reten-
`tion aid is preferably used in an amount of about 0.05
`to 2.5 % by weight based on the dry weight of the fiber
`solids and,
`in any event,
`in an amount sufficient
`to
`promote the effectiveness of the polyisocyanate. Both the
`polyisocyanate and the cationic retention aid can be added
`as dilute aqueous dispersions. A11 emulsifying agent
`should be used with the polyisocyanate to effect a better
`and more uniform dispersion.
`It is to be understood that other conventional addi-
`tives such as fillers and the like can be added. Repre-
`sentative fillers are talc, CaCO-3, silica and so forth.
`The following examples are illustrative of the process
`and products of the present invention and are not to be
`considered as limiting. All parts are by Weight unless
`otherwise indicated.
`
`EXAMPLE 1
`
`To a one liter sample of a 0.8% aqueous dispersion
`of pulp taken from a bleached kraft pulp beaten at 1.6%
`by weight solids for 30 minutes in a Valley Laboratory
`Beater were «added with mixing 1% dimeryl isocyanate
`and 1% of the quaternary ammonium guar ether of
`Example A (D.S. 0.1), the precentages being based on the
`dry weight of the pulp solids. The dimeryl
`isocyanate
`was added as a 1% by weight aqueous emulsion using
`0.2% by weight Triton X-114 (Rohm & Haas) as an
`emulsifying agent (Triton X-114 is a reaction product of
`t-octylphenol and 7-8 mols of ethylene oxide). Single
`handsheets were produced from the resulting mixed dis-
`persion (about 6.5 pH,
`temperature 25°C.) using a
`Noble and Wood Handsheet machine. The wet sheets
`
`U!
`
`10
`
`20
`
`25
`
`30
`
`35
`
`40
`
`50
`
`U1C71
`
`60
`
`65
`
`70
`
`75
`4
`
`4
`
`

`
`3,589,978
`
`9
`were dried at about 210° F. until dry in appearance. The
`dried sheets were well sized to water, aqueous alkali and
`aqueous acid.
`In contrast,
`sheets prepared from the
`aqueous pulp dispersion without additives were not sized.
`at all and with 1% and 2% by weight of the dimeryl
`isocyanate without
`the gum ether were" only slightly
`sized.
`
`EXAMPLE 2
`
`10
`from fat acids of 16 to 22 carbon atoms and (2) a quater-
`nary ammonium polygalactomannan gum ether cationic
`retention aid to the dispersion before forming the disper-
`sion into sheets, said polyisocyanate being used in an
`amount sufficient to increase the water repellency of the
`sheets.
`‘
`2. The process of claim 1 wherein x is 2 and y is I.
`3. The process of claim 2 wherein the quaternary am-
`monium polygalactomannan gum ether is an ether of a
`polygalactomannan gum and a quaternary ammonium
`compound having the formula
`R1
`I
`R4-If“’-R2-—Z“
`Ra
`
`where Z is an anion, R1, R2 and R3 are radicals contain-
`ing not more than 18 carbon atoms selected from the
`group consisting of alkyl, substituted alkyl, alkene, aryl,
`substituted aryl and cyclic groups formed by joining two
`of such radicals, and R4 is selected from the group consist-
`ing of
`
`it
`1120-10-35-— and XH2c—c-—R5—
`0
`OH
`
`10
`
`20
`
`25
`
`To 200 parts room temperature water was added 0.1
`part
`Igepal CO—-530 emulsifier
`(an alkylphenoxypoly
`(ethyleneoxy)ethanol) and 1 part dimeryl
`isocyanate.
`The resulting combination was mixed for about
`five
`minutes to disperse the dimeryl
`isocyanate and then 1
`part of the quaternary ammonium guar ether of Example
`G was added with mixing until
`the dispersion became
`viscous (about 15 minutes). This viscous dispersion was
`added to portions of an aqueous pulp dispersion and
`handsheets were prepared and dried as in Example I
`except that the pH and temperature of the aqueous pulp
`dispersions were varied. The amount of the dimeryl
`isocyanate and ether retention aid was also varied. The
`resulting handsheets had the properties as set forth in
`the following table.
`TABLE
`
`Test series
`2
`3
`
`4
`
`5
`
`1
`
`where R5 is a divalent alkylene group having from 1 to
`3 carbon atoms and X is a halogen atom.
`4. The process of claim 3 wherein R1, R2 and R3 are
`methyl and the polygalactomannan gum is guar gum.
`5. The process of claim 4 wherein R contains 34 carbon
`atoms and is the divalent hydrocarbon group of the di-
`merized fat acids derived from the mixture of fat acids
`obtained from tall oil.
`6. The process of claim 5 wherein the diisocyanate
`is used in an amount of about 0.05 to 2.5% by weight
`based on the dry weight of the cellulosic fiber solids.
`7. The process of claim 6 wherein the quaternary am-
`monium guar ether is used in an amount of about 0.05
`to 2.5% by weight based on the dry weight of the cel-
`lulosic fiber solids.
`8. The product prepared by the process of claim 1.
`
`References Cited
`UNITED STATES PATENTS
`
`2,813,093
`3,058,873
`3,084,092
`3,236,832
`3,448,101
`3,455,883
`3,471,362
`3,499,824
`
`11/1957 Gordon __________ __ 162-178
`10/1962 Keim ____________ __ 162-178
`4/1963 Arlt _____________ __ 162--158
`2/1966 Opie _______________ 162-178
`6/1969 Billy _____________ __ 162-175
`7/1969 Kamal et al. ____ __ 260—453A
`10/1969 Kent ____________ .._ 162—178
`3/1970 Strazdins _________ __ 162-164
`
`S. LEON BASHORE, Primary Examiner
`R. H. ANDERSON, Assistant Examiner
`
`162—178, 182
`
`U.S. Cl. X.R.
`
`6.5
`54
`29.5
`32.6
`31.5
`
`1.08
`1.04
`.97
`5.3
`
`30
`
`35
`
`Pulp dispersion:
`6.5
`8.5
`6.5
`4.5
`H________ _.
`40
`25
`25
`25
`Temp.,
`Cobb test 1:
`0.125................................ .. 28.4 28.4 25.4 30.5
`0.250___________________________ __ 33.6 32.6 30.5 32.6
`0.52___________________________ .- 33.6 31.5 30.5 32.6
`Water immersion tes
`.07 1.07
`0.125.......... ._
`.01
`.98
`0.250................................ --
`.95
`.93
`0.53. _ . _ . _ _ _ . . _ . . . _ _ . . .
`. . . . . __
`Wetburst4:0.1252...................... _- 4.8
`4.1
`
`
`
`.98 1.05
`.93 1.02
`.94 1.01
`6.0
`4.7
`
`1 Cobb Test T 441 M—ValueS are grams of water taken up per square
`meter of paper surface after contact with water 1% inch deep for two
`(0.125% handsheets) and five~(0.250 and 0.5 handsheets) minutes.
`2 The numbers 0.125, 0.250 and 0.5 indicate the percent by weight of
`each of the dimeryl isocyanate and quaternary ammonium polygalacto-
`mannan gum ether used in the various test series, said percent being
`based on the weight of pulp solids.
`3 Water Immersion Test T 491 sM—Va1ues are grams of water taken up
`by the paper, surface and edges, 6 square inches, after 10 minutes im-
`mersion in water about 3 inches deep.
`4 Wet burst—Values in pounds after 15 minutes soaking in tap water
`(average of five tests per handsheet).
`
`The above data show that paper prepared according to
`the present invention has improved water repellency and
`wet strength. It also shows that the water repellency is
`increased somewhat as the pH and temperature of paper
`manufacture increases (one minute sorption time). The
`noted improvements are reduced as the amount of dimeryl
`isocyanate and retention aid are lowered.
`The embodiments of the invention in which an exclu-
`sive property or privilege is claimed are defined as
`follows:
`
`1. In the process of preparing paper from an aqueous
`dispersion of cellulosic fibers, the improvement compris-
`ing adding (1) an organic polyisocyanate of the formula:
`[R}[(GH2)yNC0].
`where y is 0 or 1, x is an integer of 2 to about 4 and R
`is the hydrocarbon group of polymerized -fat acids derived
`
`40
`
`45
`
`50
`
`55
`
`60
`
`5