MXPA99011392A - High-resistance paper product in wet and s - Google Patents

Abstract

The present invention relates to a soft, flexible but strong paper product is provided by the unique configuration of particular pulp types, cationic wet strength resins and anionic processing aids.

Description

HIGHLY RESISTANT PAPER IN WET AND DRY BACKGROUND OF THE INVENTION In industrial paper and consumer products, resistance is an important characteristic. For example, in industrial consumer paper towels both wet and dry strength are important characteristics for the operation and user acceptance of a towel. Many fiber and chemical supplies and processes have been used in the attempt to obtain both a wet strength and increased sec, while maintaining other characteristic factors in a favorable light, such as the cost of material, the costs of production, product efficiency, product feel. The methods and products that have provided a soft but strong sheet of paper are very well received and are those directed to a sheet dried through air and not creped, such as that described in the patents of the United States of America numbers 5,048,589; 5,399,412; 5,607,551; 5,616,207; 5,672,248; 5,746,887 and in the pending patent application of the United States of America series No. 08 / 310,186 filed on September 21, 1994, all of which have been assigned to Kimberly-Clark, and whose descriptions are incorporated herein by reference.

SYNTHESIS OF THE INVENTION In one embodiment of the present invention, a strong and soft absorbent paper product was provided which comprises: papermaking fibers, an anionic processing aid, and a cationic moisture resistance resin; The product has a basis weight of from about 15 to about 80 grams / square meter; a GMT of at least 220; and its GM module of less than about 11,000 G, this paper product can also comprise fibers for making paper having a percent RBA of from about 17 to about 22, a number of fibers per gram of from about 5. million around 9 million, and a carboxyl content in meq / 100 g from about 1.5 to about 3.0. This paper product can be a paper towel and the fibers for making paper can be fibers having a percent RBA of at least about 17 and the anionic processing aid can be a carboxymethyl cellulose. This paper product can be multi-layered or mixed. This paper product may also have a GM modulus ratio over the GM tension (eg GM modulus / GM tension) of less than about d 12.

In another embodiment of the present invention there is provided a soft and strong absorbent paper product comprising: papermaking fibers having less than about 9 million fibers per gram; an anionic processing assistant; and less than about 18 kilograms / metric ton of cationic wet strength resin; the paper product has a basis weight from about 30 to about 5 grams / square meter and a wet transverse direction tension of at least about 730 grams. This paper product can also comprise fibers for paper that have a percent RBA of from about 17 about 22, a number of fibers per gram of from about 5 million to about 9 million, and a carboxyl content. in meq / 100 g of from about 1.5 to about d 3.0. This paper product can be a paper towel and the papermaking fibers can further comprise papermaking fibers having a percent RBA of at least about 17 and the anion processing aid can be a carboxymethyl cellulose. This paper product can be multiple layers or it can be a single layer mixed sheet.

In yet another embodiment of the present invention there is provided a soft and strong absorbent paper product comprising: paper-making fibers selected from the group consisting of NB-88 pulp, Marathon pulp, and K-lOs pulp; u anionic processing auxiliary, a cationic moisture resistance resin; the paper product has a GMT of at least about 2,200; and a basis weight of from about d 25 to about 50 grams / square meter.

In another embodiment of the present invention, it provides a soft and strong absorbent paper product which comprises: papermaking fibers, an anionic processing aid, and a cationic wet strength resin; The product has a basis weight of from about 15 to about 80 grams / square meter; a GMT of at least about 2,200; and a GM module of less than about 10,000 g. This paper product can also have a G-module ratio over GM tension of less than about 12. 10 DRAWINGS Figure 1 is a schematic process flow diagram generally showing the manufacturing of products paper.

^ (^ Figure 2 is a schematic process flow diagram showing generally the manufacture of air-dried and non-creped paper products.20 Figures 3A, 3B and 3C are diagrams showing the physical properties of the sheets .

DETAILED DESCRIPTION OF THE CURRENTLY PREFERRED INCORPORATIONS OF THE INVENTION It has generally been found that the use of particular fibers in combination with cationic wet strength resins and anionic processing aids gives rise to a unique and surprising paper product having increased wet and dry strengths, as measured, for example. , for the tests established here. The unique combination of these variables in the papermaking supply that is used in an air-drying process and not creped as set forth in the aforementioned patents and Kimberly-Clark Corporation patent applications, which are incorporated here by reference, it gives rise to paper products with "greatly improved properties and characteristics.

Generally, the sheets of the present invention can have tensile and wet tensile strengths in the transverse direction of about 10% to about 30 when compared to a sheet having a similar basis weight chemical addition rates, but which does not otherwise employ the unique combination of this invention.

Referring to Figure 1, which is a very general schematic process flow diagram of a papermaking process, the cellulose fibers are prepared in a pulp reducer (not shown) to form an aqueous solution of fibers and water, which is mentioned as supplying supply solution. The supply is pumped to a chest which can be mentioned as a deposit box. From the 5 deposit box the supply is pumped to another holding box 2, which can be mentioned as a machine chest. From the machine chest the supply is pumped by the fan pump 3 to the head box 4 of the paper making machine 5. On or before the fan pump, and supply is diluted with water. Usually, and in a preferable way, the dilution is done with return water, mentioned as white water, from the paper making machine. The flow of white water is shown by lines 6 and 7. Before the dilution the supply is mentioned as a thick supply, and after the solution the supply is mentioned as a watery supply. ^ 1 ^ The water supply is then dewatered by the forming section 8 of the paper machine to form an embryonic tissue of moist cellulose fibers. The wet fabric is then transferred to a dryer 9, which removes the water from the wet tissue forming a sheet of paper. The sheet of paper then leaves the dryer and rolls onto a reel 10.

It is understood that Figure 1 is a general description of the process for making paper and that it is intended to illustrate the process and that it does not in any way mean that it limits the scope of the present invention. Many variations in this process and in the team are known by those skilled in the art of papermaking. For example, various types of dryers can be used including air dryers, Yankee dryers with and without creping, tunnel driers and can dryers or any combination of these. Although the scheme generally shows a twin wire type forming section, other forming sections known in the art may be used. Additional components can be added or removed from the process. For example, grids, filters and refiners, which are not illustrated, can typically be placed between the pulp reducer and the headbox. The transfer section 11 of the paper making machine may not be present or may be expanded to include additional water removal device. Additional steps can also be added on the machine after the dryer before the reel such as calendering and the use of the size press, even though additional drying is usually required after the application of the size press is used. . The calendering and coating operations can also be carried out outside the machine.

Figure 2 illustrates a more specific type of apparatus and process for making paper along the lines of the process described in the aforementioned patents and Kimberly-Clark patent applications which are incorporated herein by reference. In this figure 2 a twin wire former is shown having a head box for making paper layers 10 which injects or deposits a stream 11 of an aqueous suspension of fibers to make paper in the forming fabric 13 which serves to support and bringing the freshly formed humid fabric down in the process to the partially dewatered fabric at a consistency of about 10% by dry weight. Further dewatering of the humid fabric can be carried out, such as by suction with vacuum, while the wet fabric is held by the forming machine.

The wet fabric is then transferred from the forming fabric to a transfer fabric 17 which travels a slower speed than that of the forming fabric in order to impart an increased stretch to the fabric. The difference in the speeds of these two fabrics is mentioned as the percentage of rapid transfer. The transfer is preferably carried out with the aid of a vacuum shoe 18 and a fixed space or spacing between the forming fabric and the transfer fabric or a kiss transfer to prevent compression of the wet fabric.

The fabric is then transferred from the transfer fabric to the continuous drying fabric 19 with the aid of a vacuum transfer roller 20 or a vacuum transfer shoe, optionally again using a fixed separation transfer as previously described. . The continuously dried fabric can be moved at about the same speed or at a different speed relative to the transfer fabric. If desired, the continuous drying fabric can be run at a slower speed to further increase the stretch. The transfer then takes place with a vacuum aid to ensure the deformation of the sheet to conform it to the dried cloth continuously, thus giving the desired volume and appearance.

The level of vacuum used for tissue transfers can be from about 3 to about 1 inch of mercury (from 75 to about 380 millimeters of mercury), preferably about 5 inches (125 millimeters) of mercury. The vacuum shoe (negative pressure) can be supplemented or replaced by the use of positive pressure from the opposite side of the fabric to blow the fabric onto the next fabric in addition to or as a replacement to suck it onto the next fabric with vacuum. Also the vacuum roller or rollers can be used to replace the vacuum shoe.

While supported by the continuous drying fabric, the fabric is finally dried to a consistency d about 94% or greater by the continuous dryer 21 and thereafter transferred to a carrier fabric 22. The dried base sheet 23 is transported to the spool 24 using a carrier fabric 22 and an optional carrier fabric 25. An optional pressurized dump roller 26 can be used to facilitate the transfer of fabric from the carrier fabric 22 to the fabric 25. The carrier fabrics suitable for this purpose are Albany Internationa 84M or 94M and Asten 959 or 937, all of which are relatively smooth cloth having a fine pattern. Even when not shown, the calendering roller or the calendering outside of the subsequent line can be used to improve the smoothness and smoothness of the base sheet.

It will be understood that Figure 2, even though it is a more specific description of the papermaking process, is intended to further illustrate the process and not to limit in any way or narrow the scope of the present invention. Many variations in this process and in the team are known to those skilled in the art of making paper.

Generally, the anion processing assistant can be added at any point in the processes, where it is put in contact with the paper fibers before forming the wet fabric. For example, the anionic processing aid can be added to the thickened or watered supply directly and can be added to the tray (to the white hole), to the fan pump, to the head box, to the machine box, to the box. deposit or pulped xeductor. Ideally, the anionic processing aid is added to a thick supply and is optimally added to the deposit box or the pulper reducer or at a similar point in the process. It should be noted, however, that the optimum point of addition can vary from the paper making machine to a paper making machine and from paper kind to another kind of paper.

From about 1 to about 2 lbs / tons of dry paper fibers the auxiliary anionic processing can be used, ideally from about 6 to about 15 lbs / ton (about 7.5 kilograms / metric ton), and Optimally from about 8 to about 10 pounds / ton.

Anionic processing aids useful for the purposes of this invention include without limitation cellulose type products, such as carboxymethyl cellulose (CMC obtainable from Hercules, Inc., of Wilmington, Delaware), guar gums and locust bean gums. CMC-7 is an example of a class of available carboxymethyl cellulose d Hercules that can be used. Other classes may also be used including without limitation the classes having higher molecular weights. In addition to these examples of anionic processing aids, DP-80 which is a polymaleic acid copolymer developed, and marketed by FMC, Inc., can be used. The DP-80 however, requires a high temperature cure of 190 ° C for 2 minutes.

Generally, the cationic moisture resistance resin can be added at any point in the process, where it will come into contact with the paper fibers before forming the wet fabric. For example, the cationic wet strength resin can be added to the thick or watered supply directly, and can be added to the tray, the fan pump, the head box, the machine chest in the storage box. or in the pulp reducer. Ideally, the cationic wet strength resin added to the supply is thick and optimally added to the thick supply in proximity to the anion processing aid addition point. It should be noted, however, that the optimum addition point can vary from paper machine, paper machine and paper class to paper class.

From about 5 to about 50 pounds per tonne of dry paper fibers the resin of cationic wetting resistance can be used, ideally from about 24 to about 36 pounds / ton (about 12-18 kilograms / ton) metric) and optimally d from around 15 to about 20 lbs / ton.

The cationic wet strength resins useful in the invention include without limitation cationic water soluble resins. These resins impart wet strength to paper sheets and are well known in the art of papermaking. These can be obtained from companies such as Cytec, Inc., Hercules, Inc., Callaway Chemica Company, Georgia Pacific Resin, and Borden. These resins can impart either permanent wet weather resistance to the sheet. For example, without limitation, the resin ® Kymene obtainable from Hercules, Inc., of Wilmington, Delawar can be used. By way of example and without limitations, such resins include the following Hercules products.

® The Kymene 736 which is a polyethylene imine wetting (PEI) polymer. It is believed that polyethylene imine imparts wetting resistance by ionic binding to the carboxyl sites of the pulps. The Kymene 557LX is a wet strength polymer of polyamide hepichlorohydrin (PAE). It is believed that polyamide hepichlorohydrin contains cationic sites that lead to resin retention by forming an ionic bond with the carboxyl sites of the pulp. The polymer contains 3-acetylene groups which react to form the covalent bonds with the carboxyl sites of the pulps as well as cross-link with the polymer column. The product must undergo hardening in the form of heat or suffer aging due to the reaction of the acetydinium group. ® Kymene 450 is an activated base polyamide epoxide hepichlorohydrin polymer. It is speculated that as the 557LX resin resins itself ionically to the carboxyl sites of the pulps. The epoxide group is much more reactive than the acetydinium group. The epoxide group reacts with both hydroxyl and carboxyl sites on the pulp, giving for resistance to the superior wet. The epoxide group can also be crosslinked to the polymer column. ® Kymene 2064 is also an activated base epoxy polyamide epichlorohydrin d polymer. It is speculated that the Kymene 2064 imparts its resistance to wetting by the same mecanism ® ® as the Kymene 450. The Kymene 2064 differs in that the polymer column contains more epoxide functional groups than what the ® ® ® makes the Kymene 450. Kymene 450 and Kymene 2064 require curing in the form of heat or natural aging to fully react all epoxide groups, however, due to the reactivity of the epoxide group, most of the groups (80-90%) react and impart resistance to wetting out of the paper machine.

The addition points for the anionic processing aid and the cationic wet strength resin may vary or be in the same general location. Thus, the anionic processing aid can be added before, after or at the same time as the resin d resistance to cationic wetting in the process. When the anion processing aid and the cationic wet strength resin are added at or near the same general point, for example from the same box, care should be taken to separate their respective addition points. For example, the addition points should be placed on the opposite sides of the chest.

Paper sheets can be made from long paper fibers (soft wood), short paper fibers (hardwood), secondary fibers, other natural fibers, synthetic fibers, or a combination of these or other fibers known to those skilled in the art of papermaking which are to be used in papermaking. Long paper fibers are generally understood as having a length of about 2 millimeters or greater. Particularly suitable hardwood fibers include eucalyptus and maple fibers. As used herein, the term "papermaking fibers" refers to any and all of the above-mentioned arribs.

As used herein, and unless otherwise specified, the term "sheet" generally refers to any type of sheet of paper, eg, tissue, facial towe, bath, or any heavier, creped or non-creped basis weight product. mixed, of multiple layers (for example of double and triple layers) and of a single or multiple layer or stratum.

It has been found that fibers that have particular physical and chemical attributes when combined with cationic wet strength resins and anionic processing aids provide sheets that have an essentially increased strength with little or no increase in stiffness (via for example and without limitation, com was measured by the GM module and the GM / GMT module).

The following table (Table 1) summarizes the relevant fiber morphology.

It has been found that Marathon NB-88 and K-10S type pulps essentially show increased resistance when used in conjunction with cationic wetting resins and anionic processing aids. Without strength additives, the resistance to dry sheet tension is proportional to the relative joined area (RBA). The joints that link to the knit together are van der Waals junctions and hydrogen bonds. When the sheet is wetted these joints are interrupted and therefore the sheet has a low tensile strength value. Seeing the 100% soft wood chart (figure 3) it will be predicted that the K-10S will have the relative area plus alt followed by Marathon, NB-88 and finally LL-19. The 100% softwood data correspond to the above mentioned fiber morphology data. The relative bound area is determined by a method described in Ingmanson and Thode, TAPPI, volume 42, No. 1, January 1959 which is described and incorporated herein by reference.

When wet strength resins are present in the leaf, one of the primary mechanisms of failure is to share the cell wall. The more covalent bonds that are present in the fiber wall will cause the tension force to be distributed more along the fiber. The individual fiber can now see more tensile strength before the cell wall failure occurs since any given fiber section of a lower tensile force. This is one of the ® ® reasons why the Kymene 450 and the Kymene 2064 usuallyment ® work better than the Kymene 557LX. They react not sol with the carboxyl groups but also with the hydroxyl groups.

Part of this development of resistance is the resistance added to the wetted sheet by cross bonding that occurs within the polymer. Therefore, the total wet stress can be attributed to l) the number of crossed bonds that the wet strength polymer undergoes, 2) the number of covalent bonds of the pulp fiber.

The pulp was analyzed by grading to give the amount of carboxyl sites on the pulp (see Table 1). These values were determined by the standard method TAPPI T237, om-88, the description of which is incorporated herein by reference. There was a small difference between that of LL-19 and NB-88 in that the LL-19 was 0.6 meq / lOOg higher. The K-10 proved to be the highest at 2.8 meq / lOOg. The carboxyl content is important due to the creation of the ionic bond between the pulp and the cationic wet strength polymer which determines the retention of wet strength resin. The carboxyl group also binds covalently with azentadini ® ® ® (Kymene 557LX) or the epoxide group (Kymene 450 and Kymene 2064) to give permanent wetting resistance. The samples of pulp LL-19 and NB-88 were analyzed by FTIR Raman spectroscopy to see the differences in the hydroxyl and carboxyl groups. It was found that no significant difference was present.

Table 2 gives some Kymene retention data. ® Kymene retention was measured by using fluorescence spectroscopy.

When viewing the carboxyl content, the LL-19 should have a higher retention of the wet strength resin than that of the NB-88. This was verified by viewing the retention data for 100% of LL-19 against 100% of NB-88 and 62.5% of LL-19 / 37.5% of bleached quimotermomecánic pulp (BCTMP) against 62% of NB -88 / 37.5% of bleached quimotermomecánica pulp. The K-10S can be predicted as it will have the highest retention value as seen from the retention data with a value greater than 63%.

A possible explanation of the mechanism behind development of resistance to wetting with northern softwood Kraft fibers (NSWK) can be explained by viewing the morphology data (all morphology data were collected using the Kajaani FS-20 fiber analyzer). supplied by Valmet Automation, Inc., Kajaani Division, Norcorss, Ga. The experimental procedure for determining morphology using this apparatus was published in the FS-200 Operation Manual, which is available from Valmet, whose description is incorporated herein by reference). The LL-19 has the highest number of individual fibers per unit mass, then there is the NB-88, the K-10S and the Marathon. Looking at carboxyl content, K-10S has the highest carboxyl content, then LL-19, NB-88 and finally Marathon. Among less fibers per given unit of mass or basis weight, the greater are the covalent bonds per fiber that can be formed that will result in a stronger sheet. The higher carboxyl content of the fiber determines the available sites for the covalent bond with the wet strength resin. Therefore, it was speculated that those two mechanisms combine to give the expected and synergistic effects of the present invention. Even though this is the present theory, this theory does not limit the scope of the invention in any way. This is provided merely as an explanation for these unexpected synergistic results obtained by the present invention in an effort to advance the knowledge of this art.

The tests were carried out using a continuous hand sheet forming that was configured to operate in a non-creped air drying mode to evaluate the following process parameters: Effects of 100% kraft fiber supply of North Suav wood A. 100% supply of kraft softwood fiber of nort single B. Mixture of LL-19 with NB-88 and Marathon Effects of the mixture of 62.5% of kraft fibers of north softwood / 37.5% (bleached quimotermomechanical pulp) Example 1 100% Fiber Pulp Kraft d Soft North Wood Supplies that consist of 100% fiber Northern softwood kraft (see Table 3) was dispersed separately in a pulped hydroreductor for 20 minutes at a consistency of 4%. Each supply was transferred to a deposit coffer and finally to a machine chest. Once in the machine chest, each supply was diluted to a 1% consistenci ®. The Kymene 450 was added to the 1% supply at an aggregate rate of 12 kilograms / ton and allowed to stir for 10 minutes. Subsequently, 3 kilograms / ton of carboxymethyl cellulose (CMC) were added to the same supply. The complete mixture of pulp and resin was allowed to mix for another 1 minute before tissue manufacture.

Each aqueous mixture of pulp and resin was made into tissue in a similar manner. The thick supply was further diluted to 0.1% in the fan pump and deposited on an Albany 94M forming fabric through the headbox. After vacuum draining, the fabric was quickly transferred to -20% to a Lindsay 965 cloth using a vacuum pick-up shoe. The fabric was then transferred to a Lindsay T-119-3 fabric which was wound through a dryer through electric air and dried to a consistency of 95%. The dried fabric was rolled into a soft roll on the reel.

All samples of soft roll were conditioned for a minimum of 4 hours at 23 ° C and 50% relative humidity before the test. The dry tension in the machine direction and in the transverse direction was measured using the following procedure. A 3-inch-wide sample of a stratum was cut in the specified direction using a normal cutting board. The 3-inch-wide strip is inserted into the jaws of an Instron apparatus, model No. 1122 (from Instron, Inc., of Canton, Massachusetts), with an extension of 4 inches. The sample was extended to failure using a crosshead speed of 10 inches per minute. Stress and stretch values were recorded. A total of 10 samples were tested. The module in the machine direction in the transverse direction of the tissue were measured by calculating the inclination of the stress / strain curve between 70 and 157g.

The wet tension test was carried out in a similar manner. Before the test, each sample was cut into a strip 3 inches wide and artificially aged by 105 ° C minutes. Once aged, each specimen was formed into a loop by holding both ends of the test sample and imbibing them in distilled water so that the water completely wet the sample. The excess water was removed by touching the lowermost wetted curve of the curl with the blotting paper. The sample was then inserted into the Instron apparatus and measured according to the above mentioned procedure. Care should be taken not to let the water transmit too much up the sample; otherwise, a fault in the jaws will occur producing erroneous results.

As used herein, the term "GMT" is equal to the square root of the product of the tension in the direction of the dry machine multiplied by the tension in the dry transverse direction. The GMMod (GM Module) is equal to the square root of the product of the module in the direction of the dry machine multiplied by the module in the transverse direction and dry.

From these data in Table 3, there is evidence of synergism between the pulps with a relatively higher bound area and the kymene 450 and carboxymethyl cellulose. 100% Marathon, NB-8 and K-10S are significantly higher in humid tension in the transverse direction and lower in stiffness in the presence of Kymene 450 and carboxymethyl cellulose than LL-19.

Some additional results and observations made in relation to these supplies are set forth below: A. 100% Supply of Soft Mader Kraft fiber of the North Unique • Using Kymene 450 / carboxymethyl cellulose, K-10 gave the highest GMT followed by Marathon, NB-88 and finally LL-19 in descending order.

® • Using Kymene 450 / carboxymethyl cellulose, K-10 gave the wet in the highest transverse direction followed by the NB-88, Marathon finally LL-19 in descending order.

• With no added chemicals and no statistical claims, the LL-19 produced the lowest voltage values, both humid in the transverse direction and GMT.

• Without added chemicals, the stress values of K-10S and Marathon GMT were higher than those of LL-19 and NB-88.

• With chemical resistance to wetting, 100 kraft softwood fibers from the nort had a higher GMT and a transverse direction dampening than that of the 62.5% supplies of kraft fiber from mader. soft north and 37.5% bleached quimotermomecánica pulp.

• With wet strength chemicals, 100% d softwood kraft fibers from the north a higher GMT and a dampening in the transverse direction superior to that of the 62.5% supplies of soft mader kraft fibers from the north / 37.5% bleached quimotermomechanical pulp. 25 Kymene® 557LX / carboxymethyl cellulose produced a slightly higher GMT than that of Kymene 450 / carboxymethyl cellulose in NB-88 and K-10S. However, due to the CHF footprints being on separate time periods there is much variability involved with the realization of exact conclusions.

® ® Kymene 2064 / carboxymethyl cellulose gave a GM 34% higher and a wet tension in the transverse direction 29% higher, with essentially a wet / dry ratio equal to 40% in NB-88 against LL-19.

B. Mixture of LL-19 with NB-88 and Marathon • At 25% replacement of softwood supe (SSW), both the NB-88 and the K-10S produced a significant increase of 8.5% and 11.9% in the dry tension in the transverse direction d 15% super soft wood replacement.

At 100% of NB-88 and K-10S, a significant increase of 3.7% and 12.3% in tension dry in the transverse direction was observed a substitution of 50% super softwood.

At 15% substitution of super softwood, both the NB-88 and the K-10S produced an increase of 18.8% and a significant 11.1% that was observed in the wet in the transverse direction of the composition of 100% LL- 19 • The 40% substitution of NB-88 produced a significant increase of 14% observed in the wet in the transverse direction of 25% d NB-88 substitution. • 50% substitution K-10S produced a significant increase of 12.8% in the humid tension in the transverse direction over that of the 40% replacement of K-10S.

• The 100% super soft wood level, both NB-88 and K-10S produced a significant increase of 13.6% and 19.3% in the wet tension in the transverse direction on the substitution of 50% super soft wood . 25 Example 2 - Mixture of 62.5% Northern soft wood Kraft fibers / 37.5% bleached quimotermomecánic pulp Using conditions similar to those used in Example 1, with a mixed sheet having 62.5% northern softwood kraft fiber and 37.5% bleached quimotermomechanical pulp, the following was observed: • A 95% confidence level with Kymene 450 / carboxymethyl cellulose, 62.5% NB-88 / 37.5% d quimotermomechanical pulp bleached was significantly higher in wet in the transverse direction and GMT than 62.5% d Marathon / 37.5% quimotermomecánic pulp bleached and 62.5% of LL-19 / 37.5% of bleached quimotermomecánica pulp.

• At the 95% confidence level with Kymene 450 / carboxymethyl cellulose, 62.5% d Marathon / 37.5% bleached quimotermomecánic pulp was higher in the humid tension in the transverse direction and GMT than 62.5% d LL-19 / 37.5% of bleached quimotermomecánic pulp.

Without chemicals, n fiber supplies offered significant differences for GMT, wet tension in the transverse direction and wet / dry.

® The Kymene 2064 / carboxymethyl cellulose chemistry did not offer a significant difference in wet tension in the transverse direction and GMT in supplies of 62.5 Marathon / 37.5% bleached quimotermomecánic pulp and 62.5% NB-88 / 37.5% bleached thermochemomechanical pulp.

There is no evidence of synergism between specific pulp d types, cationic wet strength resins and anionic processing aids. For example, a synergism between NB-88 and Kymene 450 and carboxymethyl cellulose was shown in the examples. 100% of NB 88 is significantly higher in the wet tension in the l cross direction and the GMT with the Kymene 450 / carboxymethyl cellulose than 100% of the LL-19. The 62.5% NB-88 / 37.5% bleached quimotermomechanical pulp is significantly higher than the wet tension in the transverse direction and the GMT co ® Kymene 450 / carboxymethyl cellulose than with 62.5% LL-19 / 37.5 of bleached quimotermomechanical pulp. The NB-88 and the LL-19 both as single pulp supplies and combined with bleached quimotermomechanical pulp have essentially the same strengths when no chemistry is present. Similarly, the K-10S and the Marathon in the presence of Kymene 450 / carboxymethyl cellulose have the same synergistic effect as ® NB-88 does in the presence of Kymene and carboxymethyl cellulose. The K-10S proved to be the fiber pulp Northern softwood kraft more superior material in the examples. A replacement of NB-88 or K-10S with LL-19 at a range of 25-35% provided a significant synergistic improvement in wet tension in the transverse direction and GMT at a 95% confidence level. These conclusions and data are generally shown graphically in Figures 3A, 3B and 3C.

The data comparison sheets used in the present invention with sheets are not set forth in Table 3.

Table 3

Claims (14)

R E I V I N D I C A C I O N S

1. A soft and strong absorbent paper product comprising: fibers for making paper, an anionic processing aid and a cationic wet strength resin; the product has a basis weight of from about d 15 to about 80 grams / m2; a GMT of at least 2200 a GM module of around 11,000 g.

2. The paper product, as claimed in clause 1, characterized in that the fibers for paper comprise said papermaking fibers having a relative area of about 17 about 22, a number of fibers per paper. gram from about 5 million to about 9 million, and a carboxyl content in meq / 100 g from about 1.5 to about d 3.0.

3. The paper product, as claimed in clause 1, characterized in that the product is a paper towel and the papermaking fibers comprise papermaking fibers having a percent relative area of at least about 100% paper. 17 and the anionic processing aid is a carboxymethyl cellulose.

4. The paper product, as claimed in clauses 1, 2 and 3, characterized in that the product is d multiple layers.

5. The paper product, as claimed in clauses 1, 2 and 3, characterized in that the product is mixed.

6. The paper product, as claimed in clause 1, characterized in that the proportion of the module GM over GM stress is less than around 12.

7. A soft and strong absorbent paper product comprising: papermaking fibers having less than about 9 million fibers per gram; an anionic processing assistant; and less than about 18 kg / metric ton of a cationic wet strength resin; The paper product has a basis weight of from about 30 about 50 grams / m2 and a tension in the wet transverse direction of at least about 730 g.

8. The paper product, as claimed in clause 7, characterized in that the fibers for making paper comprise fibers for making paper having a relative united area porcient of from about 17 to about d 22, a number of fibers per gram from about millions to about 9 million, and a carboxyl content in meq / 100 g from about 1.5 to about: 3.0.

9. The paper product, as claimed in clause 7, characterized in that the product is a paper towel and the papermaking fibers also comprise papermaking fiber having a percent of relative area relative to the paper. less than around 17; and the auxiliary anionic processing is a carboxymethyl cellulose.

10. The paper product, as claimed in clauses 7, 8 and 9, characterized in that the product is d multiple layers.

11. The paper product, as claimed in clauses 7, 8 and 9, characterized in that the product is mixed.

12. A soft and strong absorbent paper product comprising: papermaking fibers selected from the group consisting of NB-88 pulp, Marathon pulp and K-10S pulp; or anionic processing aid and a cationic wet strength resin; the paper product has a GMT of at least about 2200; and a basis weight of from about 25 to about 50 grams / m2.

13. A soft and strong absorbent paper product comprising: fibers for making paper, an anionic processing aid, and a cationic wet strength resin; the product has a basis weight of from about d 15 to about 80 grams / m2; a GMT of at least d around 2200; and a GM module of around 10,000 g.

14. The paper product, as claimed in clause 13, characterized in that the ratio of the GM module to the GM voltage is less than about 12. E S U E N A soft, flexible yet strong paper product is provided by the unique configuration of particular pulp types, anionic processing auxiliary cationic wet strength resins.