JPH02224626A - Soft tissue paper - Google Patents

Abstract

PURPOSE: To obtain soft and flannel-like feeling, high bulkiness sensible by touching, and physiological surface smoothness, by giving specific basis weight and density and cellulose fiber and a small amount of a polysiloxane substance to tissue paper and regulating the amount of polysiloxane to a specific ratio of the dry fiber weight of the tissue paper. CONSTITUTION: Tissue paper, which has the basis weight of about 10-65g/m<2> and the fiber density of not higher than about 6g/cc and containing a polysiloxane of about 0.004-2% to bring high softness, has highly sensitive softness and smoothness and silky and/or flannel-like feeding. Siloxane has hydrogen bond functional groups selected from the group of amino, carboxyl, hydroxyl, ether, polyether, aldehyde, ketone, amide, ester, and thiol, and hydrogen bond functional groups exist at a substitution mole percentage not higher than about 20%.

Description

BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to tissue paper, and more particularly to tissue paper having a soft, silky, flannel-like feel and high tactile bulk and physiological surface smoothness. Regarding high bulk tissue barber.

BACKGROUND INFORMATION Soft tissue paper is commonly preferred as disposable paper towel, facial and toilet tissue.

However, known methods and means for increasing the flexibility of tissue paper usually have an adverse effect on tensile strength. Therefore, in the design of tissue paper products, it is usually a challenge to balance flexibility against tensile strength.

Both mechanical and chemical means have been introduced with the aim of producing soft tissue paper, ie tissue paper that is perceived by users as soft to their touch.

Although the flexibility that can be sensed by touch is not particularly limited, elasticity, flexibility (-(flexl
bl 1ily) and smoothness, as well as a subjective feeling of silk or flannel. The present invention improves the quality of tissue paper, especially high bulk products, by the introduction of chemical additives, especially substances that impart a silky or flannel-like feel to the tissue paper without making the tissue paper product feel greasy or squishy to the user. Creped (c
(reped) relates to improving the tactile softness of tissue paper.

Examples of such chemical additives include, for example, polysiloxane materials, hereinafter simply referred to as polysiloxanes. In addition, surfactants can also be added to further increase flexibility and/or surface smoothness and/or to at least partially compensate for any reduction in wettability caused by the polysiloxane; Binder materials such as
or linting propensi
ty) can be added to at least partially compensate for the increase in ty).

Representative high bulk creped tissue papers that are quite soft by current standards and amenable to the increased flexibility of the present invention are disclosed in the following US patents:
Lawrence H. Sanford
l, '3anf'ord) and James B. Sisson (1% 7 years 1)
No. 3,301,746, dated May 31: Peter G. Ayers
No. 3,974, dated August 10, 1976.
No. 025; George Morgan Jr.

(Gcorge Morgan, Jr.) and Thomas P. Rlch 19
No. 3,994,7 issued in November 1976 with 30 units.
No. 71 - Ball D. Trokhan (Paul D, T
No. 4,191,609, dated March 4, 1980 to Paul ◆D.
No. 7,859. Each of these papers is characterized by a pattern of dense areas, ie, areas denser than the remainder of each of them, where such dense areas are compacted during papermaking, such as by the cross-knuckles of the imprint carrier fabric. arises from something. Other high bulk soft tissue papers include Jerry I.E. Carstens 1
U.S. Patent Section 4,3, issued November 17, 981
No. 00,981; and Nidward R. Wells (E.
dvard R, Melts) and ThoIas^, l1ensler 19
It is disclosed in each specification of No. 4,440,597 issued on April 3, 1984. In addition, obtaining high bulk tissue paper by avoiding gross densification before final drying has been demonstrated by D.L.Sha
w) in U.S. Pat. The avoidance of overall densification in
No. 3,812,000 issued May 21, 1974.

Chemical dehydrators and their theory of action, such as those considered in Sarputsi above, are published by Freemark (Prieaaa et al.
rk) et al., August 1973, No. 281].
, 755, 220; Melsel et al. 1
No. 3゜844.8 issued on October 29, 974
No. 80; and No. 4,158.594 issued January 19, 1979 to Becker et al. Other chemical treatments that have been proposed to improve tissue paper include, for example, Kenji Hara et al.'s West German Patent Boxes 3 and 4.
No. 20,940, i.e., impregnating toilet tissue paper with a combination of a silicone oil, such as dimethyl silicone, and a vegetable, animal or synthetic hydrocarbon oil to provide cleanliness and ease of wiping. There is a way.

In addition, a well-known mechanical method of increasing the tensile strength of paper made from cellulose bulbs is by mechanically refining the bulbs before papermaking. Generally, the higher the degree of refinement, the higher the tensile strength. However, consistent with the above discussion regarding tissue tensile strength and flexibility, a high degree of mechanical refinement of cellulose bulbs will have a negative impact on the flexibility of tissue paper, but other factors such as eroded papermaking furnish and process There is no change in all aspects. However, by application of the present invention, the tensile strength can be increased without adversely affecting the flexibility; on the other hand, the flexibility can also be improved without adversely affecting the tensile strength.

SUMMARY OF THE INVENTION In one aspect of the present invention, an effective amount of a polysiloxane, such as a polysiloxane, having a basis weight of about 10 to about 65 g/rtf, a fiber density of about 0.6 g/cc or less, and exhibiting, for example, high flexibility, is provided. Tissue paper containing chemical additives is provided. The tissue paper has a high degree of tactile softness and smoothness and a silky and/or flannel-like feel. Preferably, the tissue paper has a dry fiber weight of about 0.00
4 to about 2% of such chemical additives, more preferably the amount of such additives is about 0.004 to about 0.3%.
It is.

Preferred chemical additives for use in accordance with the present invention are polysiloxanes, including amino-functional polydimethylpolysiloxanes, where up to about 10 mole percent of the polymer side chains are amino-functional. Contains. As a display method, the degree of substitution is not directly related to the average molecular weight, and since the molecular weight of polysiloxane is difficult to confirm, the viscosity of polysiloxane is used as an index that can objectively confirm the molecular weight. Thus, for example, substitution of about 2% has been found to be very effective for polysiloxanes having viscosities of about 125 centistokes, but Valid with or without substitution. In addition to such substitutions with amino functions, useful substitutions can also be made with carboxyl, hydroxyl, ether, polyether, aldehyde, ketone, amide, ester and thiol groups. Among these useful substituents, the group with amino, carboxyl and hydroxyl groups is more preferred than the others, with the amino function being the most preferred.

Examples of commercially available polysiloxanes include Dow Corning (
Dov Cornlng) Dow 8075 and Dow 2
00; and Union Carbide
t+1de) silk sweatshirt (Sl 1wet)
720 and Ucarsll E P S
There is.

The chemically treated tissue paper of the present invention is used to at least partially compensate for any reduction in the wettability of the tissue paper that would otherwise result from the introduction of the polysiloxane and/or to the tactilely perceptible surface of the tissue paper. The composition may also contain an effective amount of surfactant to enhance anti-slip properties. Preferably, the amount of surfactant is equal to or less than the dry fibers of the tissue paper.
about 0.01 to about 2%, more preferably about 0.0%
5% to about 0.5%. Moreover, preferably the surfactant is non-cationic so that the tissue paper is manufactured to substantially avoid post-manufacturing changes in the properties of the tissue paper that would otherwise result from the introduction of the surfactant. It is virtually immobile in place after being removed. This is achieved, for example, by the use of surfactants with melting points above the temperatures normally encountered during storage, transportation, merchandising, such as about 50° C. or above, and the application of tissue paper product examples of the invention.

Moreover, the tissue paper according to the invention containing chemical additives does not suffer from any decrease in tensile strength or increase in linching properties that would otherwise occur due to the introduction of S&S modifiers and surfactants, if present. White binder substances, such as starch, to at least partially compensate.

It may further contain the amount of movement. The effective amount of binder material is approximately 0 on a dry fiber weight basis of the tissue paper.
．． 01 to about 2% is preferred.

Particularly preferred tissue paper examples of this invention include about 0.00% of a chemical additive such as a polysiloxane that can impart a silky, flannel-like feel. 0.04 to about 0.3%: surfactant content: 0.1 to about 2%: and starch, containing about 0.1 to about 2%, but all amounts of these additives are based on the dry fibers of the tissue paper. It is based on weight.

DETAILED DESCRIPTION OF THE INVENTION Briefly stated, the present invention provides tissue paper having a silky flannel-like feel and tactile high softness due to the incorporation of chemical additives such as polysiloxanes. Such tissue paper may further contain an effective amount of a surfactant and/or a binder material such as starch. Generally speaking,
Surfactants may be included to enhance the tactile physiological surface smoothness and/or to obtain sufficient wettability for the intended purpose of the tissue (e.g., toilet tissue); The binder material also at least partially eliminates any reduction in tissue paper tensile strength and/or deterioration in linching properties that would otherwise occur due to the addition of chemical additives and, if used, surfactants. It can be included in order to capture it. However, as the preferred chemical additive is polysiloxane, the terms "chemical additive" and "polysiloxane" are used herein partially interchangeably; however, this does not limit the scope of the present invention. It is not intended to be limited to tissue paper containing polysiloxane itself or to limit the term "chemical additive" to polysiloxane itself.

Without intending to be bound by any theory of operation and thereby limit the invention, the tissue paper examples of the invention are typically found within the ternary parameter domain defined by the following parameters in the empirically determined ranges: Characterized by: firstly, the ratio of their total flexibility to their total strength; secondly, their physiological surface smoothness; and thirdly, their frictional slip and
Stick (811p-and-8tick) coefficient. For example, tests conducted in accordance with the following procedure showed that for the ternary parameter region of the present invention, the ratio of total flexibility of about 0.13 or less to their total tensile strength: about 0.95
Physiological surface smoothness of less than or equal to about 0.033 for patterned dense tissue papers and about 0.0 for tissue paper examples having substantially uniform density.
It is defined as a slip and stick coefficient of friction of 38 or less. Conversely, all current tissue papers tested and not examples of the present invention were outside this ternary parameter range. These parameters and test methods are described below.

Flexibility and Total Flexibility - As used herein, flexibility is defined as the slope of the secant line of a graph curve derived from force vs. elongation % data, where the secant line is at the origin (0% elongation). , force 0) and force/c+++ pass through a point on the graph curve whose width is 20 g. For example, the sample width is 1c! 1 with a force of 20 g per a
For a sample that stretches by 0% (i.e. 0.1e+n/cm length), (0%.

The slope of the secant line passing through (0) and (10%, 20) is 2.0 using the following formula: direction) flexibility and cross-machine direction
-dlrecHon) Flexibility- means the geometric mean. However, this is the square root of the product of machine direction flexibility and cross machine direction flexibility (g/am).

Total Tensile Strength As used herein, total tensile strength means the geometric mean of the breaking strength g/sample width em in the machine and cross machine directions. However, this is the square root of the product of the breaking strength in the machine direction and the breaking strength in the cross-machine direction (g/sample width cf11).

The ratio of UniP factor total flexibility to total tensile strength was determined to be a factor that characterizes embodiments of the present invention as having high bulk flexibility while being strong. This ratio is hence called the WABY factor.

Total Tensile Strength For example, a sample with a total flexibility of −20 g/cm and a total tensile strength of 154 g/am has a Unipie factor of 0.13.

Briefly, the tactile softness of a tissue paper is inversely proportional to its Unipie Factor, and limited experimental data indicates that exemplary tissue papers of the present invention have a Unipie Factor of about 0.13 or less. It shows. Furthermore, it must be noted that the Unipie factor is dimensionless since both the flexibility and total tensile strength as mentioned above are g/■ and their ratio is dimensionless.

Physiological Surface Smoothness Unknown Physiological surface smoothness as used in the literature refers to a profilometer with a diamond needle.
The profilometer is a factor (hereinafter referred to as PSS factor) obtained by scanning a tissue paper sample in the machine direction with a profilometer (see below). KATOTECII CO, LTD.
) manufactured by Surf'aeeTester
) installed in a surface testing device such as the KE S-F B-4. In this tester, the tissue sample is placed on a motorized drum and the hand is gravity deflected towards the drum at the 12 o'clock clock position. The drum is rotated to give a sample speed of 111/sec, moving the sample 2 cm relative to the probe. Therefore, the probe is 2
Scan a sample length of cm. The profilometer is equipped with a means of balancing the needle to provide a normal force of 270 g. Essentially, the device detects the vertical displacement (dragon) of the needle as a sample length of "cm" is scanned under the profilometer probe. The resulting needle amplitude versus needle distance scan data is digitized and Then North Carolina 27605. Ralelgh,
Post Office Box (PostOffice B)
ox) 10066 SAS Institute, Inc. (S
The needle amplitude versus frequency spectra are converted to needle amplitude versus frequency spectra by performing a Fourier transform according to the Proe 5pectra standard program manufactured by AS Institute, Inc. This clarifies the spectral content in the topography of the sample, but the frequency spectral data is then adjusted for human tactile responsiveness as quantified and reported by Berry (Ronald T. Berry). Mouth (Ronald
Verrllo T., “Effect of contractile muscle area on vibrotactile thresholds,” Journal of the Acoustical Society of America (Jour
nal or the Aeoustreal 5oc
iety orAmerica), Volume 35, No. 1%
2 pages, 1% 3 years].

However, since the belly-mouth data are in the time domain (i.e., 7 second cycles) and physiological surface smoothness is related to finger-to-sample velocity, the belly-mouth data is based on a standard finger-to-sample velocity factor of 65 mm/sec. is converted to the spatial domain (i.e., cycle/dragon). Finally, the data is integrated over θ~10 cycles/11. The result is the PSS factor. According to the figure, the PSS factor is the area under the Verilot tuning frequency (cycles/square) versus needle amplitude curve at θ~10 cycles/long.

Preferably, the PSS factor is an average value obtained by scanning a large number of samples (eg, sample 10) both forward and backward.

The profilometers mentioned above are more specifically Gould 5urf'analyzer Equipment Controllers, all manufactured by Federal Products of Providence, Rhode Island.
quipa+cntController) #21-
1330-20428, probe #21-3100-4
65, Diamond needle tip (radius 0.0127 mm) #
210120-00 and needle tip extender (ex
tcnder) #22-0129-00. The profilometer probe assembly is equipped with a counterbalance and is assembled as shown in FIG. 22 of U.S. Pat. No. 4,300,981 (see above).
.

Slip-and-stick coefficient of friction Slip-and-stick coefficient of friction (hereinafter referred to as S&S C0F
) is defined as the average deviation of the coefficient of friction. It is dimensionless. This can be determined using a commercially available test device, such as the quad-surface tester described above, equipped with needles placed and arranged to slide over the surface of the sample being scanned, such as a fritted glass disk. When a sample is scanned as described above, the device senses the lateral force on the needle as the sample is moved or scanned beneath it. The lateral force is called the frictional force, and the ratio of the frictional force to the needle weight is the friction coefficient ll. The instrument then answers the following equation to determine the S&S COF for each scan of each sample.

In the above formula, μ is the ratio of friction force to probe load; T is the average value of μ; and X is 2 cm.

Returning now to the detailed description of the invention, the polysiloxane treated tissue paper having high tactile responsiveness of the present invention includes, but is not limited to, conventional felt compressed tissue paper; There are patterned densified tissue papers such as those exemplified; and high bulk densified tissue papers such as those exemplified by Sarputsi. Tissue paper may be of homogeneous or multilayer construction, and tissue paper products made therefrom may also be of single or multilayer construction. Preferably, the tissue paper has a basis weight of about 10 to about 65 g/ce and a density of about 0.60 g/ce or less. Preferably, the basis weight is about 35g
/rrr or less, and the density is about 0.30 g/cc or less. Most preferably, the density is about 0.08 to about 0.20 g/
ce or less.

Papermaking fibers that can be used in the present invention include fibers obtained from water valves. Other cellulosic fibrous pulp fibers such as cotton linter bagasse and the like may also be used and are considered within the scope of this invention. Synthetic fibers such as rayon, polyethylene and polypropylene fibers can also be used in combination with natural cellulose fibers.

An example of a polyethylene fiber that can be used is Pulpex™ manufactured by Hercules, Wilmington, P.A.
).

Available wood valves include kraft, chemical valves produced by sulfite and sulfuric processes, and mechanical pulps include, for example, ground wood and thermomechanical pulps and chemically modified thermomechanical pulps.

However, chemical valves are preferred because they impart superior tactile softness to tissue sheets made therewith. Pulps obtained from both deciduous trees, sometimes called "groundwood," and coniferous trees, sometimes called "softwood," can also be used.

In addition to papermaking fibers, the papermaking furnish used to make the tissue paper structure may have other ingredients or materials added to it, such as wet strength and -temporal wet strength resins.

Suitable polysiloxane materials for use as S&S modifiers in the present invention include polymers, oligomers, copolymers, and other multimonomeric siloxane materials.

The term polysiloxane as used herein includes all such polymers, oligomers, copolymers and other multimonomeric siloxane materials. Moreover,
Polysiloxane may be linear or branched, or may have a cyclic structure.

Preferred polysiloxane materials include those having monomer siloxane units having the following structure. In the above formula, R1 and R2 for each siloxane monomer unit each independently represent any alkyl, aryl, alkenyl, alkaryl, aralkyl, cyclo Alkyl, halogenated hydrocarbon or other group. Any such group may be substituted or unsubstituted. The R and R2 groups of any particular monomer unit may be different from the corresponding functional groups of the next adjacent monomer unit. Furthermore, the group may be linear or branched, or may have a cyclic structure. The groups R1 and R2 are further and each independently,
Other silicone functional groups may also be used, such as, but not limited to, siloxanes, polysiloxanes, and polysilanes. The groups R and R2 can also have any of a variety of organic functional groups, including, for example, alcohol, carboxylic acid, and amine functional groups.

The degree of substitution and the type of substituents have been found to influence the relative variation in soft, silky feel and hydrophilicity imparted to the tissue paper structure. Generally, the degree of soft silkiness imparted by a polysiloxane increases as the hydrophilicity of the substituted polysiloxane decreases. Amino-functional polysiloxanes are particularly preferred in this invention.

Preferred polysiloxanes include linear organopolysiloxane materials of the following general formula: where each R1-
Each R9 group is independently any Cl-C1-substituted alkyl or aryl group, and Rlo is any substituted C
1-010 alkyl or aryl group. Preferably, each RIR9 group is each independently any C,-C4 unsubstituted alkyl group. Those skilled in the art will recognize that there is no technical difference whether, for example, R9 or Rlo is a substituent. The molar ratio of b to (a plus b) is preferably from 0 to about 20%, more preferably from 0 to about 10%, and most preferably from about 1 to about 5%.

In one particularly preferred example, R1-R9 are methyl groups and Rlo is a substituted or unsubstituted alkyl, aryl or alkenyl group. Such materials are generally described herein as polydimethylsiloxanes with appropriate specific functional groups fi in the specific case. Examples of polydimethylsiloxanes include, for example, polydimethylsiloxane, polydimethylsiloxane having an alkyl hydrocarbon R1o group and one or more amino, carboxyl,
hydroxyl, ether, polyether, aldehyde,
There are polydimethylsiloxanes having other R1o functional groups including ketones, amides, esters, thiols and/or alkyl and alkenyl analogs of such functional groups.

For example, an amino-functional alkyl group as Rlo is an amino-functional or aminoalkyl-functional polydimethylsiloxane. This exemplary list of polydimethylsiloxanes is not meant to exclude others not specifically listed.

The viscosity of the polysiloxanes useful in this invention typically varies over a wide range, so long as the polysiloxane is flowable or can be made to be flowable upon application to tissue paper. It can vary within. This includes, but is not limited to, approximately 25 centistokes, which ranges from approximately 20,000,000 centistokes to approximately 25 centistokes.
Some have a viscosity of centistokes or higher.

High viscosity polysiloxanes which themselves are resistant to flow can be prepared by, for example, emulsifying the polysiloxane with a surfactant or bringing the polysiloxane into solution with the aid of a solvent such as hexane, not shown for illustrative purposes only. can be effectively deposited onto a tissue paper web. Specific methods of applying polysiloxanes to tissue paper webs are described in further detail below.

However, without intending to be bound by sweeping theory, it is clear that the tactile efficacy of polysiloxane is directly related to its average molecular weight;
It is also believed that viscosity is directly related to molecular weight.

Therefore, since it is relatively difficult to directly measure the content of polysiloxanes compared to determining the viscosity, tissue paper has a high tactile responsiveness, i.e., flexibility, silkiness ( Viscosity is used herein as the apparent operating parameter for imparting flannel-like properties.

References disclosing polysiloxanes include U.S. Pat. No. 2,826,551, issued March 11, 1958 to Geen;
No. 3,%4,500 issued June 22, 1976 to Pader;
U.S. Patent No. 4,36 issued December 21, 1982
No. 4,837; and Woolston (% Woolston)
l:: 1%0 There are specifications of British Patent No. 849,433, published on 28 September 2009. Furthermore, in 1984, Petrarch Systems Co., Ltd. (Petrarch 5y
"Silicon Compounds", pages 181-217, distributed by S.T.S.S., Inc., contains numerous listings and descriptions of polysiloxanes in general.

The polysiloxane is produced either as it is produced on the paper machine or afterwards, either when it is wet (i.e. before final drying) or when it is dry (i.e. after final drying). Can be applied to tissue paper. Preferably, the polysiloxane-containing aqueous mixture is sprayed onto the tissue paper as it passes through a paper machine, such as, but not limited to, either before or after the pre-dryer. or even after a Yankee dryer/creeping position, although the web is preferably creeped after the polysiloxane is applied;
9isson) (see above), reference is made to the overall arrangement paper making machine disclosed in J.P. 9isson) (see above).

Preferably, the polysiloxane is applied to a wet web in an aqueous solution, emulsion or suspension.

The polysiloxane can also be applied as a solution containing a suitable non-aqueous solvent, such as hexadiene, in which the polysiloxane is soluble or miscible.

The polysiloxane may be supplied in bulk form or preferably emulsified with a suitable interfacial emulsifier. Emulsified polysiloxanes are preferred for their ease of application, since the raw aqueous polysiloxane solution must be agitated to prevent separation into water and polysiloxane phases.

Preferably, the polysiloxane is applied after web formation has taken place. In a typical process, the web is formed prior to polysiloxane application and then dewatered to reduce loss of polysiloxane due to elimination of free water. The polysiloxane has a fiber consistency of about 15% or more in the wet web during the production of conventional pressed tissue paper; and the newly formed web leaves a fine mesh fourdrinier machine with a relatively coarse imprint. It is preferably applied to a wet web having a fiber consistency of about 20 to about 35% in the manufacture of tissue paper by a paper machine which is transferred to a carrier fabric. The reason is that it is preferable to transfer at a time when the fiber consistency is low enough that the fibers are substantially mobile during transfer, and yet after drainage has proceeded in the paper machine and their mobility has essentially disappeared, the polysiloxane This is because it is preferable to apply. Additionally, the addition of polysiloxane at high fiber consistency ensures greater retention in and on the paper, i.e. less water is removed from the web to increase its fiber consistency. It will no longer be lost.

Methods for applying polysiloxanes to webs include spraying and gravure printing. Spraying is most preferred because it is economical and allows for precise control of the amount and distribution of polysiloxane. Other less preferred methods include depositing the polysiloxane on a forming wire or fabric and then contacting the tissue web; and incorporating the polysiloxane into the furnish prior to web formation. . Suitable equipment for spraying the polysiloxane-containing liquid onto the wet web includes a 2 mm nozzle manufactured by V-1.B Systems, Inc., Tucker, Georgia. There is an external mix air pulverization nozzle. A suitable device for printing polysiloxane-containing liquids onto a wet web is a rotogravure printer.

The polysiloxane should be applied evenly to the tissue paper web. Uniform distribution is desirable so that substantially the entire sheet has the tactile effect of the polysiloxane.

Both continuous and patterned distributions fall within the scope of the invention and meet the above criteria.

Polysiloxanes can be applied to dry paper webs by similar methods described above for wet paper web polysiloxane treatments.

It has surprisingly been discovered that low levels of polysiloxane applied to tissue paper structures can exhibit a softened, silky, flannel-like, non-greasy feel without the aid of additives such as oils or lotions. Ta. Importantly, these benefits can be obtained in many instances of the present invention with high wettability within the desired range for toilet paper. Preferably, tissue paper treated with polysiloxane in accordance with the present invention contains about 2%
Contains the following polysiloxanes. Polysiloxane approx. 2
It is an unexpected advantage of the present invention that tissue paper treated with less than % of polysiloxane has substantial softness and silkiness effects imparted thereto with such low levels of polysiloxane.

Generally, tissue papers having less than about 0.3% polysiloxane, preferably less than about 0.2%, have increased softness, silkiness, and flannel-like properties;
However, it maintains sufficient wettability for use as toilet paper without the need for the addition of surfactants to compensate for any adverse wettability effects from polysiloxanes.

The minimum level of polysiloxane to be maintained in tissue paper is that level that is at least effective in imparting a tactile distinction to the paper in terms of softness, silkiness, or flannel-like properties.

The minimum effective level depends on the specific type of sheet, the method of application, the specific type of polysiloxane, and whether the polysiloxane is supplemented with starch, surfactants, or other additives or treatments. fluctuate. There is no limit to the extent of polysiloxane retention that can be applied with tissue paper, but preferably at least about 0.004%;
More preferably at least about 0.01%, even more preferably at least about 0.05%, and most preferably at least about 0.1% of the polysiloxane is retained by the tissue paper.

Preferably, a sufficient amount of polysiloxane to impart a soft feel is applied to both sides of the tissue paper, ie, to the outer surface of the surface level fibers. When the polysiloxane is applied to one side of the tissue paper, some of it typically penetrates at least partially into the interior of the tissue paper. In a preferred example, sufficient polysiloxane to provide tactile responsiveness is permeated through the entire thickness of the tissue paper so that both surfaces can impart the effects of the polysiloxane to it.

When a polysiloxane is applied to one side of a wet tissue paper web, one method that has been found to be useful in promoting polysiloxane penetration to the opposite side is to It is to vacuum dehydrate the tissue paper from the side.

In addition to treating tissue paper with polysiloxanes as described above, it has also been found desirable to treat such tissue paper with a surfactant. This can be any surface-active substance that can be present as an emulsifier for polysiloxanes.

Tissue papers containing more than about 0.3% polysiloxane are preferably treated with surfactants when considered for applications where high wettability is desired. Most preferably, a non-cationic surfactant is applied to the wet tissue paper web to obtain an additional softening effect on a constant tensile basis as described above. The amount of surfactant required to increase hydrophilicity to the desired level depends on the type and level of polysiloxane and the type of surfactant. However, as a general guideline, from about 0.01 to about 2%, preferably from about 0.05 to about 2%
If about 0.5% surfactant is retained in the tissue paper, levels of polysiloxane of about 2% or less are sufficient to provide high enough wetting properties for most applications, including toilet paper. considered to be sufficient.

However, the high wetting effect is applicable even at levels of polysiloxane well above 2% if a sufficient amount of surfactant is incorporated into the tissue paper.

Preferred surfactants for the present invention are non-cationic;
More preferably, it is nonionic. However, cationic surfactants can also be used. Non-cationic surfactants include anionic, nonionic, amphoteric and zwitterionic surfactants. Preferably, the surfactant, as described above, is used to ensure that the tissue paper is produced in a way that substantially avoids post-production changes in the properties of the tissue paper that would otherwise result from the introduction of the surfactant. It is then virtually immobile in situ. This is achieved, for example, by the use of surfactants with melting points above the temperatures normally encountered during storage, transportation, merchandising, such as about 50° C. or above, and the application of tissue paper product examples of the invention. Additionally, it is preferred that the surfactant is water soluble when applied to a wet web.

The level of non-cationic surfactant applied to the wet tissue paper web to produce the flexibility/tensile effect ranges from the minimum effective level required to impart such effect on a given tensile basis for the final product. Up to about 2%: preferably about 0.01 to about 1%, more preferably about 0.01 to about 0.5%, most preferably about 0.05% as non-cationic surfactant retained in the web.
~about 0. The range is 3%.

Preferably, the surfactant has an alkyl chain of 8 or more carbon atoms. Examples of anionic surfactants include linear alkyl sulfonates and alkylbenzene sulfonates. Examples of nonionic surfactants include:
Clove II: (Croda.

CrodestaTM S L-40 manufactured by Inc., New York, New York
Alkyl glycoside esters such as; w, K, Langton (W, K.

alkyl glycoside ethers, such as those described in U.S. Patent No. 4,011,389, issued March 8, 1977 to
Glyco Chemicals, In
c.) Alkyl glycosides, including alkyl polyethoxylated esters, such as Pegosperse™ 200 ML manufactured by Greenwich, CT. The above list of example surfactants is merely illustrative and is not meant to limit the scope of the invention.

The surfactant, in addition to any emulsifying surfactant that may be present on the polysiloxane, can be applied with similar methods and equipment used to apply polysiloxanes. These methods include spray and gravure printing. Other methods include application to the forming wire or fabric prior to contact with the web. Any surfactant other than the polysiloxane emulsifying surfactant is hereinafter referred to as a "surfactant" and any surfactant present as an emulsifying component of the emulsifying polysiloxane is hereinafter referred to as an "emulsifier."

The surfactant is applied to the tissue paper at the same time, after or before the polysiloxane.

In a typical process, surfactants are applied after formation of the wet web and before final drying. The non-cationic surfactant is preferably applied at a fiber consistency level of about 10% to about 750%, more preferably about 15% to about 35%. Surprisingly, a non-cationic interface applied to a wet web? Retention of the A-type agent is high even when it is applied under conditions where the surfactant is not ionically significant to the fiber. Retention rates in excess of about 90% are expected at preferred fiber consistency without the use of chemical retention aids.

As mentioned above, it is also desirable to treat polysiloxane-containing tissues with relatively low levels of binders, such as starches for lint control. Preferably, the tissue paper is treated with a liquid solution and the sheet is preferably wet at the time of application.

In addition to reducing linting in the final tissue vapor product, even low levels of starch reduce the linting that would occur with higher levels of starch addition.
It provides a modest improvement in the tensile strength of tissue paper without imparting stiffness (ie stiffness).

It further provides improved tensile strength compared to conventionally reinforced tissue papers, such as sheets with higher tensile strength due to increased bulb refinement or addition of other dry strength additives. A tissue paper having a flexibility relationship is obtained. This result is particularly surprising. This is because starch has traditionally been used to provide strength at the expense of flexibility in applications where flexibility is not an important property, such as paperboard. Additionally, starch has been used as a filler for printing and writing papers to improve surface printability.

Generally, starches suitable for the practice of this invention are characterized by water solubility and hydrophilicity. Examples of starch materials include corn starch and potato starch, without thereby intending to limit the range of suitable starch materials, and waxy corn starch, known commercially as amloea starch, is particularly preferred. Amiocadene differs from regular corn starch in that it is all amylopectin, whereas regular corn starch contains both amylopectin and amylose. The various unique characteristics of Amioka Denbun are:
“Amizai-starch from waxy corn”, H, H,
Shop Meyer 01. H.

Schopmcyer), Food Industries, 1945 1
February, No. 106=108 pages (No. 1476-1478)
It is further described in.

The starch may be in granular or dispersed form, although granular form is preferred. Preferably, the starch is sufficiently cooked to induce expansion of the granules.

More preferably, the starch granules are expanded, such as by cooking, immediately before dispersing the starch granules. Such highly expanded starch granules are called "fully cooked." Dispersion conditions usually vary depending on the size of the starch granules, the crystallinity of the granules and the amount of amylose present. Fully cooked amioca starch can be prepared, for example, by heating an aqueous slurry of starch granules at about 4% consistency for about 30 to about 40 minutes at about 190 mm.

Examples of other starch materials that can be used include National Starch and Chemical Co. (National Starch and Ch.
There are modified cationic starches such as those manufactured by Chemical Company (Bridgewater, New Jersey). Such modified starch materials have hitherto been primarily used as bulb product additives to increase wet and/or dry strength. However, when applied according to the present invention by application to a wet tissue paper web, they will be less effective on wet strength compared to wet-end additions of similar modified starch materials. Given that such modified starch materials are more expensive than unmodified starches, the latter was usually preferred.

Starch must be applied to tissue paper while the paper is in a wet state. The starch matrix material is preferably added to the tissue paper web when the web has a fiber consistency of about 80% or less. Non-cationic starch materials are retained in the web sufficiently to have an observable effect on flexibility at certain strength levels even with increased refinement, but from about 15% to about 80%.
It is preferably applied to a wet tissue web having a fiber consistency of .

Preferably, the starch is applied to the tissue paper web as an aqueous solution. Application methods include the same methods described above for polysiloxane applications, preferably by spraying, less preferably by printing. The starch is applied to the tissue paper web at the same time, before or after the addition of the polysiloxane and/or surfactant.

Preferably, an effective amount of starch is applied to the sheet to increase lint control and associated strength upon drying, at least as compared to an otherwise identical sheet that is not treated with starch. Preferably from about 0.01% to about 2.0% starch, calculated on a dry fiber weight basis, is retained in the dryer sheet, and more preferably from about 0% starch is retained in the dryer sheet.
, 2 to about 1.0% starch matrix material is retained.

Analysis of the amount of treatment chemical retained in the tissue paper web can be performed by any method accepted in the application industry. For example, the level of polysiloxane retained by tissue paper is measured by solvent extraction of the polysiloxane with an organic solvent, followed by atomic absorption spectroscopy to examine the silicon levels in the extract; nonionic surfactants such as alkyl glycosides Levels of anionic surfactants, such as linear alkyl sulfonates, are determined by extraction with organic solvents, followed by gas chromatography to determine surfactant levels in the extract; Δp1 is determined by colorimetric analysis of the post-extract; starch levels are determined by amylase digestion of starch to glucose, followed by colorimetric analysis to determine glucose levels. These methods are exemplary and are intended to determine the level of a particular component retained by the tissue paper.
This is not meant to exclude other methods that may be useful for determining

The hydrophilicity of tissue paper refers to the tendency of the tissue paper to become wetted with normal water. The hydrophilicity of a tissue paper may be quantified somewhat by determining the time required for a dry tissue paper to become completely wetted with water. This time is called the "wetting time". In order to provide a test method that is consistent and repeatable with respect to wetting time, the following procedure is used to constant the wetting time; ) tissue paper (1) A dry (fiber consistency level greater than 90%) sample unit sheet is prepared; second, the sheet is folded in parallel in quarters and then folded into a back diameter of approximately 0.75 inches (approximately 1
．． 9 cm) to about 1 inch (about 2.5 cm) balls. Thirdly, the ball-shaped sheet is placed on the surface of distilled water at 72 degrees (approximately 22 degrees Celsius), and a timer is started at the same time; fourth, the ball-shaped sheet is completely wetted.
The timer is stopped and read when the timer is pressed. Completion of wetting is visually observed.

The preferred hydrophilicity of tissue paper depends on its intended end use. In the case of tissue paper used in various applications, such as toilet paper, complete wetting is desired in a relatively short period of time in order to prevent clogging when draining in the toilet. Preferably the wetting time is 2 minutes or less. More preferably,
Wetting time is 30 seconds or less. Most preferably, the wetting time is 10 seconds or less.

The hydrophilic properties of the tissue paper examples of the invention can of course be determined immediately after production. However, a substantial increase in hydrophilicity occurs during the first two weeks after the tissue paper is manufactured, ie after the paper is two weeks old after its manufacture. Therefore, it is preferable that the wetting time is measured at the end of such two weeks E1.

Therefore, the wet time measured after two weeks at room temperature is referred to as the "two week wet time."

The density of tissue paper, as that term is used herein, is the average density calculated as the basis weight of the paper divided by the caliper (eali pcr), where appropriate unit conversions are made. The tissue paper caliper used herein is 95g
The thickness of the paper when subjected to a compressive load of /In2 (15.5 g/m2).

Applicant's representative: Mr. Sato

Claims (1)

[Claims] 1. Basis weight of about 10 to about 65 g/m^2 and about 0.6 g/m^2;
A tissue paper having a density of less than or equal to cm^3, the paper comprising cellulose fibers and a small amount of polysiloxane material, the amount of polysiloxane being at least about 0.0 cm based on the dry fiber weight of the tissue paper.
A tissue paper characterized by being made of 0.04% polysiloxane. 2. The effective amount of polysiloxane is about 0.004 to about 2 based on the dry fiber weight of tissue paper.
% of the tissue paper according to claim 1. 3. The effective amount of polysiloxane is about 0.004 to about 0 based on the dry fiber weight of tissue paper.
．． 3% tissue paper according to claim 1. 4. Polysiloxane is amino, carboxyl, hydroxyl, ether, polyether, aldehyde, ketone,
2. A polydimethylpolysiloxane having hydrogen-bonding functional groups selected from the group consisting of amide, ester, and thiol groups, wherein said hydrogen-bonding functional groups are present at a substitution mole percentage of about 20% or less. tissue paper. 5. The tissue paper of claim 4, wherein the polysiloxane has a substitution mole percentage of about 10% or less and a viscosity of about 25 centistokes or greater. 6. The tissue paper of claim 4, wherein the polysiloxane has a substitution mole percentage of about 1.0 to about 5% and a viscosity of about 25 to about 20,000,000 centistokes. 7. The tissue paper of claim 4, wherein the substitution mole percentage is about 2% and the viscosity is about 125 centistokes. 8. Further comprising a surfactant in an amount sufficient to ensure that the tissue paper has a wetting time of about 2 minutes or less after aging for 2 weeks from its manufacture.
Tissue paper as described. 9. The tissue paper of claim 8, wherein the amount of surfactant is sufficient to ensure that the two week aged tissue paper has a wetting time of about 30 seconds or less. 10. The tissue paper of claim 1, further comprising a small amount of a surfactant, the amount of which is about 0.01 to about 2% based on the dry fiber weight of the tissue paper. 11. Claim 1, wherein the amount of surfactant is about 0.05 to about 0.5% based on the dry fiber weight of the tissue paper.
Tissue paper described in 0. 12. The tissue paper according to claim 1 or 10, wherein the surfactant is non-cationic. 13. The tissue paper of claim 1 or 10, wherein the surfactant has a melting point of at least about 50<0>C. 14. A binder material in an amount effective to at least partially compensate for any decrease in tensile strength or increase in linching properties of the tissue paper that would otherwise result from the introduction of the polysiloxane and surfactant, if present. Claim 1, 8 or 10 further comprising
Tissue paper as described. 15. The tissue paper of claim 14, wherein the binder material is starch. 16. The effective amount of starch is from about 0.01 to about 2% based on the dry fiber weight of the tissue paper.
Tissue paper as described. 17. The tissue paper of claim 2 or 3, further comprising a small amount of surfactant, the amount of which is about 0.01 to about 0.5% based on the dry fiber weight of the tissue paper. 18. A binder material in an amount effective to at least partially compensate for any decrease in tensile strength or increase in linching properties of the tissue paper that would otherwise result from the introduction of the polysiloxane and surfactant, if present. The tissue paper according to claim 17, further comprising. 19. The tissue paper of claim 18, wherein the binder material is starch. 20. Claim 19, wherein the effective amount of starch is from about 0.01 to about 2% based on the dry fiber weight of the tissue paper.
Tissue paper as described.