CA1152710A - Pulp containing hydrophilic debonder and process for its application - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The invention provides a cellulosic pulp having reduced tensile strength and excellent hydro-philic properties. The pulp is produced by utilizing a hydrophilic debonder having the general formula:

X-wherein:
R1 = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [ethylene oxide]n where N = 1 to 50.
R3 = aliphatic chain of at least 4 carbon atoms.
R4 = [ethylene oxide]n or [propylene oxide]n with N = 1 to 50.
X = Cl, I, Br, SO-4, PO=4, CH3CO2.

Description

~7~0 FIEL~ OF THE INVENTION
This invention relates to a pulp having low tensile strength and excellent hydrophilic properties produced by the incorporation of a hydrophilic debonder of the quaternary amine type.
BACXGROUND OF THE INVENTION
Over the past several years there have been continuing attempts to improve specific properties of cellulosic pulp-derived products by utilization of a variety of debonding agents. These debonding agents quite frequently include a quaternary amine component because of the high degree of substantiveness of this moiety for cellulose. Examples of quaternary amine debonders can be found in U. S. patents 3,554,863;
3,554,862; 3,395,708; and Reissue 26,939 issued to Laurence R. B. Hervey, et al. Additional examples of such debonders can be found in U. S. patent 3,617,439 issued to Benjamin E. Chapman, Jr., Canadian patent ~ 1,020,935 issued to Louis S. Hurst, et al, British s 20 patents 1,282,593 and 1,180,801 also issued to Hervey, and U. S. patents 3,556,931~ 3,510,246 and 3,356,526.
Until fairly recently it has been axiomatic ' in the pulp and paper industry that the debonding function was inversely related to hydrophilicity, i.e.
the increase in efficiency of debonding as represented by reduced tensile strength would result in reduced water absorption. U. S. patent 4,144,122 issued to ., , _ ~1527~0 Jan G. Emanuelsson, et al discloses a quaternary amine compound containing repeating ethylene oxide units at two of the quaternary positions. These ethylene oxide units are attached to the ammonium ion by propylene linkages in each case and are also characterized by an ether linkage to an aliphatic chain at both positions.
According to U. S. patent 4,144,122, debonding is accomplished while the hydrophilic character of the debonded pulp is improved when compared with conven-tionally debonded pulps.
According to my invention, another class of debonding compounds has been identified which produces pulp which i9 more hydrophilic even than the pulp produced accarding to U. S. patent 4,144,122.
SUMMARY OF THE INVENTION
According to this invention, a hydrophilic debonder having the general formula:

Rl - N R3 X

wherein:
Rl = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [e~hylene oxide]n where N = 1 to 50.

R3 = aliphatic chain of at least 4 carbon atoms.

~15Z710 R4 = [ethylene oxide]n or ~propylene oxide]n with N = l to 50.
X = Cl, I, Br, SO4, PO4, CH3CO2.
Compounds of this general formula actually show increased capacity for producing hydrophilic pulp when compared to the compounds described in U. S. patent 4,144,122.
Any one or more of the selected chemicals which are defined by the general formula set forth above may be introduced into the pulp or pulp sheet at a number of different places during the commercial pulp sheet forming operations. Due to the hydrophilic properties of the pulp after treatment with the debonder, the utility for products produced from this pulp varies from fluff used in conventional absorbent materials such as sanitary napkins and diapers to absorbent sheet stock such as paper towels. It should be noted with regard to diapers that a series of absorbent tests indicates a substantial increase in the absorption of urine when compared to the more conventional debonding agents and therefore, the products of this invention have particular utility in diaper products. (Diapers and diaper products as used herein are designated specifically to include all incontinence pads and products whether they are designed specifically to be worn by an infant or adult or whether they are in sheet , form such as for use with incontinent children or , adults in a hospital or nursing home environment.) ~1527~

Quaternarv ammonium compounds according to this invention should be added to the wet cellulose pulp after delignification or bleaching, either before or during the formation into sheets or continuous webs on the cellulose pulp machine or a paper machine. The compounds are preferably in an aqueous carrier in a concentration within the range of from about 1% to about 15~ by weight of the debonder. These treating solutions may also contain conventional viscosity re-ducing additives such as ethanol, propanol, monoethylether or diethylene glycol and other additives tradi-tionally associated with the debonder addition process.
The amount of the novel debonder based upon the dry weight of the cellulose ranges from a~out 0.1% to about 5.0% and preferably between about 0.2% to about 2.5%.
The treating solution can be applied by mixing ~ith a pulp slurry. It can also be applied by spraying or dipping, by kissing rolls or any other suitable technique. Following application, the treated cellulose pulp or paper can be dried in the usual manner. The treated cellulose may be fiberized into cellulose fluff as mentioned above for utilization in various hygienic products. In all other ways, paper and pulp processing related to the handling of pulp containing these compounds is essentially conventional.
Products which fall within the definitional category of this invention are currently commercially ``" 1152710 available and sold under the trademark ETHOQ~AD by Armak Industrial Chemical Division of Akzona, Inc.
of Asheville, North Carolina, and are generally used for antistatic agents, electroplating bath additives and dye-leveling agents. Also useful are the class of compounds sold under the EMCOL trademark by Witco Chemical Company, Inc., New York, New York, used for similar purposes.
An example of the debonders of this invention follow. The example compares the debonding ability as measured by burst according to TAPPI Standard Method T403 0S-76 and tensile TAPPI Standard Method T494 0S-70.
Water absorbency is determined by the following method.
Test specimens are obtained from the debonder treated handsheets by cutting three 1" x 3" randomized strips from each sheet. It is found that 5 sheets are appro-priate for each test condition. Each strip is marked at 0.5 cm intervals for 3.5 cm starting from the edge of the 1" end.
Deionized water (surface tension = 72 dyne/cm) is placed in a two-liter glass bottle. The test strip is affixed in the bottle just above and perpendicular to the liquid surface. The level of the liquid is then adjusted until the liquid surface is just in contact with the strip. The sheet then absorbs the liquid and it rises up the strip. A light source behind the bottle alds in observing the liquid rise. When the liquid " 11527i1~

contacts the first 0.5 cm line, a timer is started.
Then each time the liquid touches the next higher 0.5 cm line, the time is recorded. This results in 90 measurements for each test condition (3 strips/sheet x 6 measurements/strip x 5 sheets/test condition).
The rate is determined by fitting the data to a regression of height climbed up the strip vs. the square root of time required. The square root arises out of consideration of the Lucas-Washburn equation.
The fits are excellent with r ~ .98 in all cases considered. This results in rates calculated to better than +4~. All data contained are corrected for density.
For all tests described, hand sheets having 60 lb/3000 ft.2 basis weight were produced. Three com-pound~ made according to the general formula of this invention were tested as debonding agents and they were as follows:

(fH2CH20) xH +
ETHOQUAD C/25 H3C-l-Cl2.56H26.03 Cl X + Y = 15 (CH2CH2O)yH i (fH2CH20) xH

ETHOQUAD O/12 H C-7-C18H35 Cl- X + Y = 2 (CH2CH2O~yH

,, .(clH2cH2cH2o) 40H +
EMCOL CC-42 H3C-7-CH2cH3 Cl-These compounds were tested against QUAKER 2006, a debonder now being sold by Quaker Chemicals of Barring-ton, Illinois; ARQUAD 2HT-75, a commercially available debonder sold by Armak Chemical, Inc., Chicago, Illinois;
and BEROCELL 579, 582 and 584 made in accordance with U. S. patent 4,144,122. The structure of the BEROCE~L
compounds are not specifically identified other than by patent number; the ARQUAD compound is a quaternary amine with a methyl group at Rl and R2 and saturated C18 groups at R3 and R4. The QUARER 2006 compound is not specifically identified by the Quaker Company but it is believed to have a five member ring structure containing two nitrogen atoms with one nitrogen double bonded to one of the carbons in the ring structure and the other nitrogen having two substituent groups bound thereto in addition to the bonding associated with the ring structure.
When compared according to the tests described above, the following table xepresents the values so determined:

'-TABLE I
Water % Burst Tensile Absorbency Additive Add'n Pulp (P.S.I.) (lbs/in) (cm/sec) None --- SSK9.02 5.47 .63 EMCOL CC-42 0.4 SSK4.19 3.90 .68 EMCOL CC-42 1.0 SSK4.00 3.44 .64 EMCOL CC-42 2.4 SSK3.33 3.10 .63 ETHOQUAD C/25 0.25 SSK 6.31 4.57 .57 ETHOQUAD C/25 0.5SSK 6.23 4.65 .55 `
10 ETHOQUAD C/25 0.7SSK 5.37 4.52 .55 ETHOQUAD C/25 1.0SSK 5.32 4.49 .54 ETHOQUAD O/12 0.4SSK 5.44 4.60 .64 ETHOQUAD O/12 1.0SSK 4.85 3.83 .60 ETHOQUAD O/12 2.4SSK 4.74 3.03 .57 QUAKER 2006 0.4 SSK6.38 3.85 .31 QUAKER 2006 1.0 SSK5.60 2.68 .30 QUAKER 2006 2.4 SSK4.04 1.68 .42 ARQUAD 2HT-75 0.4SSK 4.70 3.18 .34 ARQUAD 2HT-75 1.0SSK 3.95 2.02 .32 20 ARQUAD-2HT-75 2.4 SSK3.56 2.00 .29 BEROCELL 579 0.4SSK 4.88 2.75 .39 BEROCELL 579 1.0SSK 4.52 2.69 .39 BEROCELL 579 2.4SSK 3.81 2.00 .30 ¢~ BEROCELL 582 0.4SSK ~ 5.21 2.59 .45 BEROCELL 582 1.0SSK 3.76 1.83 .41 s BEROCELL 582 2.4SSK 3.51 1.76 .35 ~ BEROCELL 584 0.4S5K 4.10 1.86 .45 s BEROCELL 584 1.0SSK 3.22 1.45 .42 f'~

,:, :
g _ :
. .

l~S~

Water % Burst Tensile Absorbency Additive Add'n ~ (P.S.I.) (lbs/in) (cm/sec) BEROCELL 584 2.4 SSK 2.90 1.40 .38 None --- NSK11.50 8.62 .43 ETHOQUAD C/25 0.4 NSK --- 8.30 .49 ETHOQUAD C/25 1.0 NSK --- 7.65 .44 ETHOQUAD C/25 2.5 NSK --- 6.48 .42 ETHOQUAD O/12 0.4 NSK --- 7.90 .53 ETHOQUAD O/12 1.0 NSX --- 6.57 .46 10 ETHOQUAD O/12 2.5 NSK --- 5.21 .42 ARQUAD 2HT-75 0~4 NSK --- 4.60 .23 ARQUAD 2HT-75 1.0 NSK --- 3.40 .21 ARQUAD 2HT-75 2.5 NSK --- 3.75 .20 (SSK = Southern Softwood Kraft) ~NSK = Northern Softwood Kraft) , As can be seen from the above data, while adequate tensile strength reduction is obtained by the debonders of thss invention, substantially improved water absorbency is generated by the same compounds when compared, for example, to BEROCELL compounds which claim increased hydrophilicity for the debonding agents described in U. ~. patent 4,144,122. These numbers hold true to , varying levels of debonders. Even more importantly in , some instances at lower levels of addition of the de-bonder of this invention, the hydrophilicity of the debonded pulp is actually greater than that of the ~ untreated pulp.

!~

~. -- 10 --x : .

~o The table also illustrates that the data, while changing slightly as the source of pulp changes, does apply in the same general order of magnitude.
When the compounds of this invention were tested for urine absorbency, based upon a synthetic urine containing the following components:
Compound Concentration ,. g/l KH2PO4 0.681 F.W. = 136 CaH4~PO4)2~H2o F.W. = 252.1 MgSO4-7H2O 0.477 F.W. = 246.5 2S4 1.333 F.W. = 174 Na3PO4 12H20 1.244 F.W. = 380 NaCL 4.441 : F.W. = 58.4 KCL 3.161 F.W. = 74.5 NaN3 0 . 400 F.W. = 65 Urea 8.560 F.W. = 60 A Non-Ionic Surfactant 0.100 F.W. = 5000 the values obtained were again substantially greater than those of comparable commercially available debonders as can be seen from the table below:
.

Synthetic Urine ~ Absorbency Additive P _ Add'n (cm/sec~
None SSK --- .64 EMCOL CC-42 SSK 0.4 .69 EMCOL CC-42 SSK 1.0 .66 EMCOL CC-42 SSK 2.4 .64 ETHOQUAD C/25 SSK 0.25 .55 ETHOQUAD C/25 SSK 0.5 .55 ETHOQUAD C/25 SSK 0.7 .54 ETHOQUAD C/25 SSK 1.0 .53 ETHOQUAD O/12 SSK 0.4 .65 ETHOQUAD O/12 SSK 1.0 .56 ETHOQUAD O/12 SSK 2.4 .61 QUAKER 2006 SSK 0.4 .33 , QUAKER 2006 SSK 1.0 .35 i QUAKER 2006 SSK `2.4 .40 ARQUAD 2HT-75 SSK 0.4 .25 ARQVAD 2HT-75 SSK 1.0 .20 ~' ARQUAD 2HT-75 SSK 2.4 .22 None NSK --- .45 ETHOQUAD C/25 NSK 0.4 .40 ETHOQUAD C/25 NSK 1.0 .39 ETHOQUAD C/25 NSK 2.5 .40 ETHOQUAD C/25 NSK 0.4 .43 , ETHOQUAD O/12 NSK 1.0 .39 ETHOQUAD O/12 NSK 2.5 .34 ARQUAD 2HT-75 NSK 0.4 .18 ARQUAD 2HT-75 NSK 1.0 .14 ARQUAD 2HT-75 NSK 2.5 .15 ~lsmo As can be seen from the table above, sub-stantial benefits are derived fr'om the utilization of the debonder of this invention when the end product is designed to be fluff which is subsequently utilized in diapers or diaper related products.
Of course, as mentioned previously, the increase in hydrophilicity can have substantial addi-tional benefits with regard to fluff in its conventional uses such as, for example, in sanitary napkins or other hygienic products.

Claims (13)

WHAT IS CLAIMED IS:

1. A wood pulp containing a hydrophilic debonder having the general formula:

X-wherein;
R1 = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [ethylene oxide]n where N = 1 to 50.
R3 = aliphatic chain of at least 4 carbon atoms.
R4 = [ethylene oxide]n or [propylene oxide]n with N = 1 to 50.
X = Cl, I, Br, SO-4, PO=4, CH3CO2.

2. A process for treating cellulose pulp fibers to reduce interfiber bonding while preserving the hydrophilicity of the pulp comprising adding to a cellulose pulp fiber slurry prior to or during the formation of the slurry into a web a quaternary ammonium compound having the formula:

X-wherein:
R1 = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [ethylene oxide]n where N = 1 to 50.
R3 = aliphatic chain of at least 4 carbon atoms.
R4 = [ethylene oxide]n or [propylene oxide]n with N = 1 to 50.
X = Cl, I, Br, SO-4, PO=4, CH3CO2 and forming and drying said web.

3. The process according to Claim 2 wherein the quaternary ammonium compound is in an aqueous carrier of from 1% to 15% by weight.

4. The process according to Claim 2 wherein the quaternary ammonium compound applied to the fibers is from about 0.1% to 5.0% based on the dry weight of the cellulose.

5. The process according to Claim 2 in which the quaternary ammonium compound is added by spraying a solution thereof on the web and drying the web.

6. The process according to Claim 2 wherein the quaternary ammonium compound is added to the slurry of cellulosic pulp fibers and the pulp is subsequently dried.

7. A process according to Claim 2 in which the web is fiberized into cellulose fluff.

8. A process according to Claim 2 in which the quaternary ammonium compound is added during formation of the cellulose pulp fiber slurry into a web.

9. The combination according to Claim 1 wherein the debonder is present between about 0.1% to 5.0% by weight of the dry cellulosic material.

10. An absorbent fluff containing the hydro-philic debonder of Claim 1.

11. An absorbent fluff according to Claim 10 in which the hydrophilic debonder is present at a level of about 0.1% to 5.0% by weight of the dry cellulosic material.

12. A diaper containing an absorbent fluff having a hydrophilic debonder of the general formula:

X-wherein:
R1 = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [ethylene oxide]n where N = 1 to 50.
R3 = aliphatic chain of at least 4 carbon atoms.
R4 = [ethylene oxide]n or [propylene oxide]n with N = 1 to 50.
X = Cl, I, Br, SO-4, PO=4, CH3CO2.

13. An absorbent cellulosic based sheet stock having a hydrophilic debonder of the general formula:

X-wherein:
R1 = methyl, ethyl, propyl, hydrogen or hydroxyethyl.
R2 = methyl, ethyl, propyl or [ethylene oxide]n where N = 1 to 50.
R3 = aliphatic chain of at least 4 carbon atoms.

R4 = [ethylene oxide]n or [propylene oxide]n with N = 1 to 50.
X = Cl, I, Br, SO-4, PO=4, CH3CO2.