CN1328610A - Multi-ply tissue paper and method of making multi-ply tissue paper - Google Patents

Abstract

The present invention relates to a multi-ply tissue paper comprising at least two plies, said tissue paper having a surface area in a plane and a caliper perpendicular to the plane, wherein said caliper is at least 0.35 mm, and wherein the tissue paper has an unembossed wiping surface over a substantial portion of its surface, wherein said multi-ply tissue paper has an average basis weight of at least 40 g/m²Having a wet burst of at least 150 grams, and a process for making a multi-ply tissue.

Description

Multi-ply tissue paper and method of making multi-ply tissue paper

This invention relates to ply tissue paper, especially facial tissue and disposable handkerchiefs.

Paper webs or sheets, sometimes called tissue paper or tissue paper webs or sheets, have a wide variety of uses in modern society. The articles are commercially available in large quantities as facial and toilet paper. It has long been recognized that the four important physical properties of these products are their strength, softness, absorbency (including absorbency into aqueous systems), and lint resistance. Various research and development efforts have been focused on improving one of these properties without seriously affecting other properties, or on simultaneously improving two or three of the properties mentioned.

Softness is the tactile sensation a consumer feels when holding a particular product, rubbing it against the skin, or rubbing it in the user's hand. This tactile sensation is provided by a combination of several physical properties. It is generally recognized by those of ordinary skill in the art that one of the more important physical properties related to softness is the stiffness of the paper web from which the product is made. Stiffness, in turn, is generally considered to be directly related to the dry tensile strength of the web.

Strength is the ability of a product to maintain physical integrity and resist tearing, bursting and shredding under conditions of use.

Absorbency is a measure of the ability of a product to absorb a quantity of liquid, especially an aqueous solution or dispersion. Total absorbency as perceived by the consumer is generally considered to be: the total amount of liquid absorbed by a given mass of tissue paper at temperature and the rate at which a given mass of tissue paper absorbs liquid.

Lint resistance is the ability of a fibrous product, and its constituent webs, to bond together under conditions of use including wet. In other words, the higher the lint resistance, the lower the tendency of the web to lint.

WO 95/11343 (published April 27, 1995) discloses a method of making layered tissue paper. Example 3 therein discloses a two-ply facial tissue having a basis weight of about 32 g/ ^m2 (20 lb/3000 ft2 ⁾ . The tissue paper in this example contained 0.475% wet strength resin.

US-A-4481243 (issued November 6, 1984) discloses facial tissue comprising multiple layers held together by embossing only along the edges of the tissue paper.

Disposable paper products having a high wet burst strength are known, for example Bounty ^™ sold by The Procter & Gamble Company with a wet burst strength greater than 200 grams. However, the kitchen towels are embossed across the surface which would roughen the surface texture and would not provide an adequate smooth wiping surface for blowing your nose.

Facial tissue comprising at least two plies is commercially available, the tissue has a surface area in a plane and a thickness perpendicular to the plane, wherein the thickness is at least 0.35 mm, and wherein the tissue has a surface area perpendicular to the plane, wherein the thickness is at least 0.35 mm, and wherein the tissue Non-embossed wipe finish on most surfaces. However, the wet burst resistance of today's facial wipes is relatively low, often causing tears or ruptures, which in turn leads to soiling of the user's hands with mucus or other bodily fluids.

It is therefore an object of the present invention to provide a multilayer facial tissue which has at least the desired softness and absorbency of the known facial tissue but which is also resistant to use, especially when used for blowing the nose. Will provide enhanced tear or burst resistance.

Summary of the invention

The inventive object of the present invention can be achieved by a multiply tissue paper having an average basis weight of at least 40 g/ ^m2 , preferably at least 45 g/ ^m2 , and having a wet burst strength of at least 150 g, preferably at least 200 g. It is also preferred that the multi-ply tissue paper has a thickness of at least 0.4 mm. In one embodiment of the present invention, at least one of the layers comprises: a first zone and a second zone, the first zone comprising a continuous network which is macroscopically uniplanar, which is opposite to the second zone high density and low basis weight; the second zone consists of discrete domes of low density relative to the first zone, substantially all of the domes being dispersed in, surrounded by, and separated from each other. Furthermore, it is preferred that the ratio of the average basis weight of the first web zone to the average basis weight of the second zone domes is greater than 0.8 and less than 1.0.

The present invention also relates to a method for the production of multi-ply tissue paper, wherein said method comprises the steps of:

- mechanically refining a first fiber slurry, wherein said fibers have an average length of at least 2 mm, preferably the first slurry comprises a substantial proportion of softwood fibers, such as northern softwood kraft fibers;

- mixing the refined pulp with a second fiber pulp, the average length of the fibers of the second pulp is shorter than the average length of the fibers of the first pulp, preferably, the second pulp contains a large proportion of hardwood fibers, such as eucalyptus fibers ;

- providing a web on a porous surface in which the fiber composition is substantially uniform throughout the thickness of the web;

- forming layers by removing water from the web; and

- juxtaposing at least two plies to form a multi-ply tissue paper.

Most preferably, the ratio of softwood long fibers to hardwood short fibers is greater than 60:40, preferably about 70:30.

Detailed description of the invention

As a highly preferred component, the present invention may comprise up to about 3.0%, preferably at least 0.5%, more preferably at least 0.8% by weight wet strength chemicals, such as water soluble permanent and temporary wet strength resins, based on dry fiber weight .

There are several types of wet strength resins useful in the present invention. For example, Westfelt described many of these materials and discussed their chemistry in "Cellulose Chemistry and Technology" (Vol. 13, pp. 813-825 (1979)).

Typically, wet strength resins are water-soluble, cationic materials. That is, the resin is water soluble when added to the papermaking furnish. It is likely, and even expected, that subsequent processes such as crosslinking will render the resin insoluble in water. Furthermore, some resins are water-soluble only under certain conditions, such as within a defined pH range. It is generally believed that wet strength resins will undergo crosslinking or other curing reactions after deposition on, within, or between fibers of the papermaking fibers. Crosslinking or curing generally does not proceed as long as a substantial amount of water is present.

Of particular utility are various polyamide-epichlorohydrin resins. These materials are low molecular weight polymers with reactive functional groups such as amino, epoxy and azetidinyl groups. The preparation of such materials is well described in the patent literature, including US-A-3700623 (Keim issued October 24, 1972) and US-A-3772076 (Keim issued November 13, 1973).

Particularly useful in the present invention are the polyamide-epichlorohydrin resins sold under the trademarks Kymene 557H and Kymene LX by Hercules Inc. (Wilmington, Delaware). These resins are typically described in the aforementioned Keim patents.

Alkali-activated polyamide-epichlorohydrin resins useful in the present invention are sold under the trademark Santo Res by Monsanto Company (St. Louis, Missouri), such as Santo Re31. These materials are generally described in US-A-3855158 (Petrovich issued December 17, 1974); US-A-3899388 (Petrovich issued August 12, 1975); US-A-4147586 (Petrovich, April 3, 1979); and US-A-4222921 (Van Eenam, September 16, 1980).

Other water-soluble cationic resins useful in the present invention are polyacrylamide resins, such as those sold under the trademark Parez, such as Parez 631NC, by American Cyanamid Company (Sandford, Connecticut). These materials are generally described in US-A-3,556,932 (Coscia et al., issued January 19, 1971); and US-A-3,556,933 (Williams et al., issued January 19, 1971).

Other types of water soluble resins useful in the present invention include: acrylic emulsions and anionic styrene-butadiene latexes. Numerous examples of these types of resins are provided in US-A-3844880 (Meisel Jr et al., issued October 29, 1974). Some other water-soluble cationic resins that can be used in the present invention are: urea-formaldehyde resin and melamine-formaldehyde resin. These multifunctional active polymers have a molecular weight of several thousand. More common functional groups include nitrogen-containing groups such as amino groups and hydroxymethyl groups attached to nitrogen. Although less preferred, polyethyleneimine-based resins are also useful in the present invention.

A more complete description of the foregoing water-soluble resins, including methods of preparation, can be found in TAPPI (Association of Pulp and Paper Technology) Special Issue Volume 29, "Wet Strength of Paper and Board" (New York; 1965).

Temporary wet strength agents, such as modified starches, may or may not be used. Mixtures of temporary and permanent wet strength agents can be used.

The present invention may comprise dry strength chemicals in an amount preferably up to 3% by weight, more preferably at least 0.1% by weight, based on dry fiber weight. A particularly preferred dry strength chemical is carboxymethylcellulose. Other suitable dry strength chemicals include: polyacrylamides (such as the combination of Cypro ^™ 514 and Accoststrength ^™ 711 produced by American Cyanamid (Wayne, NJ); starches (such as corn starch or potato starch); polyvinyl alcohols (such as Airvol(TM) 540) manufactured by Air Products Inc. (Allentown, PA); guar or locust bean gum; and polyacrylic acid latex. Suitable starch materials may also include: modified cationic starches, such as those modified to have nitrogen-containing groups such as amino groups and hydroxymethyl groups attached to the nitrogen, which are available from the National Starch and Chemical Company ( Bridgewater, NJ).

A chemical softening composition comprising a chemical debonding agent is an optional ingredient of the present invention. US-A-3,821,068 (issued June 28, 1974) teaches that chemical debonding agents can be used to reduce stiffness and thus increase the softness of tissue webs. US-A-3554862 (issued January 12, 1971) discloses suitable chemical dissociating agents. These chemical dissociating agents include quaternary ammonium salts.

A preferred chemical softening composition comprises: from about 0.01% to about 3.0% of a quaternary ammonium compound, preferably a biodegradable quaternary ammonium compound; and from about 0.01% to about 3.0% of a polyol; preferably selected from glycerol, Sorbitol, polyglycerols having an average molecular weight of from about 150 to about 800, and polyoxyethylene glycols and polyoxypropylene glycols having a weight average molecular weight of from about 200 to 4000. Preferably, the weight ratio of quaternary ammonium compound to polyol is from about 1.0:0.1 to 0.1:1.0. It has been found that the chemical softening composition is more effective when the polyol and quaternary ammonium compound are first premixed together, preferably at a temperature of at least 40°C, prior to addition to the papermaking furnish. Additionally, or alternatively, the chemical softening composition may be applied to a substantially dry tissue web, for example by means of a printing process (Note: Unless otherwise stated, all percentages herein are by weight of dry fibers ).

Examples of quaternary ammonium compounds suitable for use in the present invention include the well known dialkyldimethylammonium and alkyltrimethylammonium salts either unmodified, or monoester or diester variants. Examples include: the diester variant of di(hydrogenated tallow)dimethylammonium methylsulfate and the diester variant of di(hydrogenated tallow)dimethylammonium chloride. Without being bound by theory, it is believed that the ester moiety confers biodegradability to these compounds. Commercially available material is available from: Witco Chemical Company Inc. (Dublin, Ohio) under the trade designation "Rewoquat V3512". Details of the analytical and testing methods are disclosed in WO95/11343 (published April 27, 1995).

Examples of polyols useful in the present invention include polyoxyethylene glycols having a weight average molecular weight of from about 200 to about 600, with "PEG-400" being particularly preferred.

The tissue papers of the present invention may be prepared by conventional methods known to those of ordinary skill in the art, such as dewatering a suitable pulp using, for example, one or more papermaking felts and/or papermaking belts.

In one embodiment of the present invention, at least one ply of said tissue paper has two main regions. The first zone comprises the embossing zone which is embossed against the carcass of the papermaking felt. The embossed zone preferably comprises a substantially continuous web. The continuous web of the first region of the paper is formed on, and generally conforms to, a substantially continuous felt carcass in geometric configuration and is closely aligned therewith during papermaking.

The second zone of the sheet contains a number of domes dispersed throughout the embossed screen area. Typically, the domes coincide in geometry and position during papermaking with the flexure ducts of the felt. During the papermaking process, the dome will protrude outwardly from the substantially continuous web area of the paper by aligning it with the flexure conduit. By aligning it with the deflection conduits during the papermaking process, the fibers in the dome will flex in the Z-direction between the paper-facing surface of the carcass and the reinforcement structure. Preferably the dome is discontinuous.

Without being bound by theory, it is believed that the basis weights of the domed regions and the substantially continuous web regions of the paper may generally be equal. By flexing the domes into the deflection conduits, the density of the domes is reduced compared to a substantially continuous mesh area. In addition, the substantially continuous areas of the web (or alternatively other patterns) may subsequently be embossed, for example, against a Yankee dryer. The embossing will increase the density of the substantially continuous web area relative to the density of the domes.

The paper of the present invention can be prepared according to commonly assigned U.S. patents: US4529480 (granted to Trokhan on July 16, 1985); US4637859 (granted to Trokhan on January 20, 1987); Smurkoski et al); and US5529664 (Trokhan et al., issued June 25, 1996) and US5679222 (Rasch et al., issued October 21, 1997); these patents are incorporated herein by reference.

If desired, the paper can be dried and prepared on a throughdrying felt without a patterned backbone. The paper will have discontinuous, high density regions and a substantially continuous web of low density. During or after drying, the paper can be subjected to various vacuums in order to increase its thickness and puff up selected areas. The paper, and associated felt, can be prepared according to the following patents: US3301746 (issued January 31, 1967 to Sanford et al); US3905863 (issued September 16, 1975 to Ayers); US3974025 (issued August 10, 1976 US4191609 (issued to Trokhan on March 4, 1980); US4239065 (issued to Trokhan on December 16, 1980); US5366785 (issued to Sawdai on November 22, 1994); and US5520778 (issued to issued May 28 to Sawdai); these patents are hereby incorporated by reference.

In another embodiment, the reinforcing structure may be a felt, also known as a press felt, which is used in conventional papermaking without throughdrying. The framework can be applied to carpet reinforcement structures as described in the following commonly assigned U.S. patents: US554970 (issued to Phan on August 27, 1996); US5556509 (issued to Trokhan et al. on September 17, 1996); December 3, 1997 to Ampulski et al.); US5609725 (March 11, 1997 to Phan); US5629052 (May 13, 1997 to Trokhan et al.); US5637194 (June 10, 1997 to Ampulski et al); US5674663 (issued October 7, 1997 to McFarland et al); US5693187 (issued December 2, 1997 to Ampulski et al); US5709775 (issued January 20, 1998 to Trokhan et al); US5814190 (VanPhan, issued September 29, 1998); and US5817377 (Trokhan et al., issued October 6, 1998); incorporated herein by reference.

If necessary, instead of the aforementioned felt having a patterned skeleton, a felt having a jacquard weave may be used. The felts can be used as forming fabrics, drying fabrics, impression fabrics, transfer felts, and the like. A jacquard weave is reported in the literature to be particularly useful when it is not desired to press or emboss the paper in the nip, as typically occurs during transfer to a Yankee dryer. Organized exemplary blankets can be found in US5429686 (issued Jul. 4, 1995 to Chiu et al.) and US5672248 (issued Sep. 30, 1997 to Wendt et al.).

Combining two or more plies of tissue paper to form a ply tissue paper. The layers may optionally be bonded together, for example by means of gluing or embossing. Gluing is not preferred as it tends to make the product stiffer and less flexible. Indeed, preferably no glue is used to bond the layers together. The layers may be bonded together by embossing, for example as described in EP-A-0755212 (published 29 January 1997). According to the present invention, the tissue paper has an unembossed wiping surface over a substantial portion of the surface of the tissue paper. As used herein, this means that the tissue paper has one or more unembossed areas, and optionally one or more embossed areas, and that the unembossed area is at least 50% of the surface area of the tissue paper. %, and up to 100%. As used herein, an embossed area is an area of tissue paper that has many embossed locations. Most commonly, the embossed area is near the edge of the tissue paper (e.g., along two or four edges); and the embossed area may also be used for decorative purposes (e.g., to create a pattern or to highlight a logo or brand name) . Unembossed areas are continuous areas between and/or surrounding embossed areas.

Alternatively, one or both surfaces of the tissue paper may be treated with a lotion. Lotions may contain emollients/debonders, emollients, fixatives and mixtures thereof. Suitable softeners/debonders include quaternary ammonium compounds, silicones, and mixtures thereof. Suitable emollients include propylene glycol, glycerin, triethylene glycol, spermaceti or other waxes, petrolatum, fatty acids having 12-28 carbon atoms in their fatty acid chain, fatty alcohols and fatty alcohol ethers, and mixtures thereof. Suitable fixatives include polyhydroxy fatty acid esters, polyhydroxy fatty acid amides and mixtures thereof. Other optional ingredients include fragrances, antibacterial actives, antiviral actives, disinfectants, pharmaceutical actives, film formers, deodorants, sunscreens, astringents, solvents, and the like. Specific examples of lotion ingredients include: camphor, thymol and menthol.

"Long fibers" as defined herein are considered fibers having an average fiber length of at least 2.0 mm. These long papermaking fibers are usually softwood fibers, preferably northern softwood kraft fibers.

"Short fibers" as defined herein are considered fibers having an average fiber length of less than 2.0 mm, preferably 0.2-1.5 mm. These papermaking staple fibers are generally hardwood fibers, preferably eucalyptus fibers. Alternatively, low cost staple fiber sources such as sulfite fibers, thermomechanical pulp fibers, chemithermomechanical pulp (CTMP) fibers, recycled fibers, and mixtures thereof may be used.

Test Methods

The wet burst strength was measured using an electronic burst strength tester and the following test conditions. The burst tester is a Thwing-Albert Burst Tester (Cat. No. 177) equipped with a 2000 gram load cell. The burst tester is provided by Thwing-Albert Instrument Company (Philadelphia, PA19154, USA).

Take eight sheets of tissue paper and stack them in pairs of two. The samples were cut with scissors, and they were cut into a size of about 228 mm (longitudinal) × 114 mm (transverse), and the thickness of each sample was twice that of the finished product.

Aging is allowed for one to two hours by connecting the stacks together with small paper clips and "fanning" the other end of the stack to separate the sheets, which will circulate air between them. Suspend each sample by means of a clamp in a forced air oven at 107°C (±3°C) for 5 minutes (±10 seconds). After the heating cycle, the sample stack was removed from the furnace and allowed to cool for a minimum of three minutes prior to testing.

Take a sample strip, hold the sample strip by its narrow transverse edges, and immerse the center of the sample in a pan containing about 25 mm of distilled water. Leave the sample in the water for 4 seconds (±0.5 seconds). Remove the sample and hold the sample to drain for three (3.0 ± 0.5) seconds so that the water drains laterally. After draining the water, perform the test immediately. Place the wet specimen on the lower ring of the specimen holder with the outer surface of the product facing up so that the wetted portion of the specimen completely covers the open surface of the specimen holder ring. If there is shrinkage, discard the specimen and repeat the test with a new specimen. After the specimen is properly placed on the lower ring, the switch to lower the upper ring is turned on. In this way, the sample to be tested is now securely clamped in the sample holding mechanism. The burst test starts immediately at this position by pressing the start button. The piston will begin to rise. When the specimen tears or breaks, record the maximum reading. The piston will automatically return and return to its starting position. The method was repeated for three more specimens, so a total of four tests, ie four replicates, were performed. Test results are reported to the nearest gram as the mean of four replicate experiments.

As used herein, the caliper of a multi-ply tissue paper is the caliper of the paper when subjected to a compressive load of 14.7 g/ ^m2 . Preferably, the thickness is measured using a Thwing-Albert Micrometer Model 89-11 low load (available from Thwing-Albert Instrument Company, Philadelphia, Pa.).

Example

An aqueous slurry containing 3% by weight northern softwood kraft (NSK) fibers was prepared in a conventional pulper. The NSK stock was refined gently and a 2% solution of permanent wet strength resin (Kymene ^™ 557H) was added to the NSK stock tube at a rate of 1% by dry fiber weight. Enhanced adsorption of permanent wet strength resins onto NSK fibers by means of in-line mixers. A 1% solution of dry strength resin (carboxymethyl cellulose) was added to the NSK pulp at a rate of 0.15% by dry fiber weight before the mixing pulp pump. The NSK slurry was diluted to a consistency of about 0.2% at the mixing slurry pump.

A chemical softening composition was prepared comprising dishardened tallow diethyl ester dimethyl ammonium chloride and polyoxyethylene glycol (PEG) having an average molecular weight of 400. Heat the PEG-400 to about 66°C and dissolve the quaternary ammonium compound in the molten PEG-400 to form a homogeneous mixture.

An aqueous slurry containing 3% by weight of eucalyptus fibers was prepared in a conventional pulper. A 1% solution of the chemical softening composition was added to the eucalyptus pulp tube at a rate of 0.15% by dry fiber weight. The eucalyptus pulp was diluted to a consistency of about 0.2% at the mix pump.

The two slurries were mixed so that the ratio of NSK fibers to eucalyptus fibers was 70:30, and the resulting slurries were deposited onto a Fourdrinier wire by means of a single-layer headbox to form a paper embryo. Dewatering is carried out by passing through fourdrinier wires with the help of water baffles and vacuum boxes. The fourdrinier net is a 5-shed, satin weave configuration with 3.3 longitudinal monofilaments and 3.0 transverse monofilaments per mm respectively.

At the transfer position, a web having a fiber concentration of about 20% is transferred from a Fourdrinier wire onto a photopolymer fabric having a Linear Idaho mesh of 0.87 per ^mm2 (562 meshes per inch2) , 40% knuckle area, and a photopolymer depth of 0.2 mm. Further dewatering was accomplished by vacuum assisted drainage until the fiber consistency of the web was about 28%. The patterned web was predried to a consistency of about 65% by weight by means of air ventilation. The web was then adhered to the surface of the Yankee dryer with a sprayed creping adhesive comprising 0.25% polyvinyl alcohol (PVA) in water. The fiber concentration was increased to about 96% before dry creping the web with a doctor blade. The scraper had an angle of impingement of about 25° and was positioned relative to the Yankee so as to provide an angle of impingement of about 81°. Manipulate the Yankee dryer at a speed of about 4m/s, and roll the dried paper on the paper shaft into a roll.

The dry web comprised: 0.7% Kymene ^(TM) , 0.11% carboxymethylcellulose, 0.05% chemical softening composition on a dry fiber weight basis.

The paper web was converted into a two-ply tissue paper product having an overall size of 210 ^mm2 . The tissue paper product was folded and packaged without embossing.

In a second embodiment, the same two-ply tissue paper product was embossed prior to folding. The edges of the tissue paper product extending about 15 mm towards the center were embossed according to the method described in WO 95/27429 (published 19 October 1995). The majority of the surface of the tissue paper product (ie all the surface within 15 mm of the edge) is not embossed.

In a third example, a previous sample was taken and decorated by embossing the trade name on the previously unembossed area. There are also four decorative leaf patterns embossed in previously unembossed areas. Each decorative pattern is approximately 30 mm ² .

The procedure of the previous examples is repeated and the paper is calendered on the reel; or during lamination of the layers; or during conversion; or it is calendered two or three times by means of a combination of these steps.

The two-ply tissue paper products of these samples had a thickness of 0.45 mm, an average basis weight of 50 g/ ^m2 , and a wet burst strength of 250 g.

Claims (10)

1. one kind comprises two-layer at least multi-layered tissue paper, and this tissue paper has surface area in a plane, and has the thickness perpendicular to this plane; Wherein said thickness is at least 0.35 millimeter, and wherein this tissue paper has the wipe surfaces of not embossing on the surface of its overwhelming majority; It is characterized in that, described multi-layered tissue paper on average quantitatively be at least 40 gram/rice ², wet bursting strength is at least 150 grams.

2. according to the multi-layered tissue paper of claim 1, wherein said multi-layered tissue paper on average quantitatively be at least 45 gram/rice ², wet bursting strength is at least 200 grams.

3. according to the multi-layered tissue paper of claim 1 or 2, wherein the thickness of this multi-layered tissue paper is at least 0.4 millimeter.

4. according to each multi-layered tissue paper of aforementioned claim, wherein one deck comprises first district and second district at least, and first district comprises the continuous net of the monoplane on the macroscopic view, and it is a high density and low quantitative with respect to second district; Second district is by forming for low-density discontinuous dome for first district, and all domes are dispersed in the described barrier basically, surrounded by described barrier, and separated from one another.

5. according to the multi-layered tissue paper of one deck at least that comprises of claim 4, wherein the average quantitative ratio of the dome in quantitatively average and second district in first barrier is greater than 0.8, and less than 1.0.

6. according to each multi-layered tissue paper of aforementioned claim, comprise the wet strength chemical agent (the % weight of total dried fiber) of at least 0.5% weight.

7. according to the multi-layered tissue paper of claim 6, wherein the wet strength chemical agent is selected from: polyamide-epichlorohydrin resins, polyacrylamide resin, or its mixture; And/or the dry strength chemical agent is a carboxymethyl cellulose.

8. a method for preparing each multi-layered tissue paper in the aforementioned claim comprises the steps:

First fiber pulp is carried out machine finish, and the average length of wherein said fiber is at least 2 millimeters;

Refining slurries are mixed with second fiber pulp, and the average fiber length of described second slurries is shorter than the average length of first pulp fibers;

The paper embryo is provided on porous surface, and the fibre fractionation in the paper embryo is uniform substantially on whole web thickness;

From the paper embryo, remove moisture content and form layer; With

Will be two-layer at least and put, thus multi-layered tissue paper formed.

9. method according to Claim 8, wherein the fiber of first slurries comprises the needle-leaved wood fibre of vast scale, and the fiber of second slurries comprises the broad-leaved wood fiber of vast scale.

10. according to the method for claim 9, wherein the ratio of needlebush long fiber and leaf wood staple fibre is greater than 60: 40, preferred about 70: 30.