KR20070061849A - Absorbent articles comprising thermosplastic resin pretreated fibers - Google Patents

Abstract

One embodiment of the present invention is a fibrous structure that may comprise: cellulosic pulp fibers and pretreated cellulosic pulp fibers. The pretreated cellulosic pulp fiber is formed by pretreating cellulosic pulp fiber with a thermoplastic resin having a property selected from the group consisting essentially of water soluble, water dispersible, and combinations thereof.

Description

ABSORBENT ARTICLES COMPRISING THERMOSPLASTIC RESIN PRETREATED FIBERS}

The present invention relates to a tissue product comprising pulp fibers pretreated with a thermoplastic.

Cellulose fibers made from wood pulp are used in a variety of tissue products such as cosmetic tissues, bath tissues, paper towels, table towels, wet tissues and the like. Methods of making tissue products comprising natural wood pulp fibers, synthetic polymeric fibers, and combinations of natural wood pulp fibers and synthetic polymeric fibers, which impart high dry and wet strength to such tissue products, are known in the art. .

Fibrous tissue webs with high strength and extensibility are useful in many applications because they ensure that the tissue product remains intact during use. Drying strength enhancers such as starch or polyacrylamide can be used. Unfortunately, the use of such additives increases the strength of the fibrous tissue web but does not increase the extensibility of the tissue product.

Increased tensile strength is generally known to reduce the soft hand of fibrous tissue webs. In general, the perceived stiffness of a fibrous tissue web typically depends on the tensile fracture strength and modulus of elasticity of the fibrous tissue web, with the high stiffness and low ductility of the fibrous tissue web being due to its high modulus and high tensile strength. The durability of the fibrous tissue web typically depends on the tensile strength and stretchability of the fibrous tissue web. In general, the higher the tensile strength and the elongation, the higher the durability of the fibrous tissue web. Thus, in order to maximize the durability and ductility of the fibrous tissue web, it is advantageous to have the highest elongation and the lowest modulus of elasticity at a given tensile strength.

High wet strength fibrous tissue webs (known in the art as wet strength) are useful in many applications. One use of such fibrous tissue webs is pre-wet tissue products, such as wet tissues, which are often used by travelers to clean their bodies or clean their surfaces. Such fibrous tissue webs and tissue products made therefrom must maintain sufficient strength to withstand wiping and rubbing when stored in wet conditions for long periods of time. Other uses of fibrous tissue webs with high wet strength are tissue products that need to maintain integrity when wetted with body fluids such as nasal secretions, urine, blood, mucus, menses and other body discharges.

In the papermaking sector, chemical additives exist to improve the wet strength of fibrous tissue webs and ultimately tissue products made from such fibrous tissue webs. Such materials are known in the art as "wet strength enhancers" and are commercially available from various sources. For example, polyamide epichlorohydrin resins can be used to enhance the wet strength of fibrous tissue webs. Such cationic resins are typically added to papermaking pulp fiber slurries, which bind onto anionic cellulose pulp fibers. In the papermaking process, the resin crosslinks and eventually becomes insoluble in water. The wet strength enhancer therefore acts as a "glue" that holds the pulp fibers together, thereby enhancing the wet strength of the fibrous tissue web. However, it is necessary to use chlorine to remove the resin and recycle or repulp tissue products containing pulp fibers treated with this resin, which causes environmental problems. "Repulping" refers to a regeneration process used to make fibrous tissue webs and tissue products from scrap fibrous tissue webs and tissue products accumulated in the manufacture of fibrous tissue webs and tissue products. Since the stalk product is typically an unused raw material, the regeneration process for future use prevents inefficient disposal of the valuable raw material of paper pulp fibers.

Cationic resins as wet strength enhancers react with other anionic additives that may be added to the fibrous tissue web, or in many cases enhance the dry strength of the fibrous tissue web to produce less soft tissue products. It may have a disadvantage. Moreover, the effectiveness of cationic wet strength enhancers can be limited by the low retention of the wet strength enhancers on cellulosic pulp fibers.

A fibrous tissue web containing individualized pulp fibers, crosslinked by a crosslinking agent (glutaraldehyde is most typical) selected from the group consisting of C2 to C8 dialdehydes, is disclosed. The costs associated with making pulp fibers crosslinked by dialdehyde crosslinkers such as glutaraldehyde may be too high for making commercially viable tissue products.

The teaching of the use of C2 to C9 monomeric polycarboxylic acids to prepare individualized and crosslinked cellulosic pulp fibers having predominantly interfiber crosslinks (crosslinks between cellulose units in a single pulp fiber) and increased absorbency is taught. It became. In addition, various resinous maleic anhydride compositions have been used in connection with fibrous tissue webs and tissue products. For example, the fibrous tissue web and / or tissue product may be coated with a composition comprising an amine salt of a low molecular weight C6 to C24 olefin / maleic anhydride copolymer in combination with bisulfite. Such fibrous tissue webs and / or tissue products exhibit release properties. The application of polymeric polyacids, phosphorus-containing accelerators and active hydrogen compounds to fibrous tissue webs followed by curing at 120-400 ° C. for 3 seconds to 15 minutes.

As used herein, the terms "pretreatment" and "pretreatment" refer to the treatment of pulp fibers and / or fibrous sheets with a chemical additive in a pulp mill before the finishing operation, to complete the finishing operation, and to finish the pretreatment on a paper mill. Redispersed pulp fibers and finished tissue treated pulp fibers and / or tissue products using pretreated pulp fibers.

As used herein, the term "water-dispersible" means that a synthetic copolymer, such as the thermoplastic resin of the present invention, may be present as a colloidal, self-emulsifying or other type of dispersion in water that is water soluble or stable in the presence of an emulsifier. It means that there is. Although emulsifiers may be added within the scope of the present invention to aid in the polymerization of the thermoplastics or to aid in the compatibilization of the thermoplastics with other chemical additives used in the papermaking process, emulsifiers are used to form a stable aqueous dispersion or solution of the thermoplastics. It is not necessary.

The water-soluble and / or water-dispersible properties of the thermoplastic resins of the present invention enable repulpating fibrous tissue webs and / or tissue products containing thermoplastic resins and / or other chemical additives. It is surprising of the present invention that thermoplastics can be retained at the wet end of the papermaking process while being water dispersible or water soluble.

A further disadvantage of using papermaking chemical additives such as wet strength enhancers is that at least some of the chemical additives are lost in the pulping and / or repulping processes. Thus, even if the original tissue product is hydrophilic, using emulsions of thermoplastic resins containing high levels of chemical additives results in a finished tissue product having unacceptably hydrophobic properties due to loss of chemical additives. Can be. Because chemical additives can be very important for the dispersibility of thermoplastics, fibrous tissue webs and / or tissue products made from water-insoluble or non-dispersible thermoplastics are pulp fibers called nits, as described below. It is easier to contain bundles.

This knit is a fiber / polymer bundle that results in the appearance of white spots on the fibrous tissue web and / or tissue product. These white spots will generally be at least one square millimeter in size. Knit count refers to the number of nits counted in a sample of 7.5 inch by 7.5 inch fibrous tissue webs and / or tissue products made from pretreated pulp fibers. The fibrous tissue web and / or tissue product should have a knit count of about 10 or less, more particularly about 5 or less, even more particularly about 3 or less.

Thus, there is a need for tissue products having the desired dry and wet strength, elongation and modulus of elasticity. It may be desirable to make a tissue product that can be easily dispersed to allow repulping.

Summary of the Invention

Disclosed herein are fibrous tissue webs and / or tissue products comprising cellulosic pulp fibers pretreated with a thermoplastic resin having properties that are water-dispersible, water soluble, or a combination thereof, and methods of making such fibrous tissue webs and / or tissue products. do. In one embodiment of the present invention, the fibrous structure includes at least about 90% by weight of cellulosic pulp fibers based on the total weight of the fibrous tissue web, and a thermoplastic resin disposed between at least some of the cellulosic pulp fibers. And a fibrous tissue web having a pair of outer surfaces. The thermoplastic resin can have properties selected from the group consisting essentially of water soluble, water-dispersible, and combinations thereof.

In another embodiment of the present invention, the fibrous structure comprises a pair of outer surfaces comprising thermoplastic resin and cellulosic pulp fibers, which may have properties selected from the group consisting essentially of water soluble, water-dispersible and combinations thereof. And a fibrous tissue web having. The thermoplastic resin may at least partially coat the cellulosic pulp fibers.

In one embodiment of the invention, the pretreated cellulosic pulp fibers may comprise thermoplastic resin and cellulosic pulp fibers attached to the cellulosic pulp fibers, wherein the weight ratio of thermoplastic resin to cellulosic pulp fibers is from about 1: 5 to About 1: 1000. The thermoplastic resin can have properties selected from the group consisting essentially of water soluble, water-dispersible, and combinations thereof.

The foregoing and other features are described below in the "Detailed Description of the Invention".

Disclosed herein are methods for making tissue products comprising cellulosic pulp fibers, tissue products, and pulp fibers pretreated with a thermoplastic resin having properties that are water-dispersible, water soluble, or a combination thereof. Tissue articles comprising cellulosic pulp fibers and thermoplastics can have high wet strength and high wet / dry ratio and can be repulped. All ranges disclosed herein are inclusive and inclusive (for example, the range of "up to about 25 weight percent, more particularly about 5 to about 20 weight percent" is an end value in the range of "about 5 to about 25 weight percent"). And all intermediate values). The terms "first" and "second" are not used herein to indicate any order, quantity or importance, but rather are used to distinguish one element from another, and the term "one" herein defines an amount. It is not intended to be created, but rather indicates that there is more than one pointed out. The modifier “about” used in reference to an amount includes the stated value and has the meaning indicated by the context (eg, including the error associated with the measurement of a particular amount).

The pretreated pulp fibers may be cellulosic pulp fibers, more particularly natural pulp fibers, even more particularly chemical pulp fibers. The pretreated pulp fibers may comprise at least about 80%, more particularly at least about 90%, even more particularly at least about 95% by weight of the cellulosic pulp fibers based on the total weight of the tissue product. The remainder of the pulp fibers in the tissue product may include, for example, bleached or unbleached pulp fibers, natural and synthetic pulp fibers (e.g. rayon, lyocells, polyethylene, polypropylene, etc.), as well as one or more pulp fibers described above. Combinations to include.

The specific size and geometry of the pulp fibers, such as aspect ratios, may vary depending on the tissue product comprising the pulp fibers. Exemplary cellulosic pulp fibers include wood pulp fibers including hardwood and softwood; Non-wood paper pulp fibers (e.g. cotton, straw, grasses (e.g. rice and esparto), rattan, reeds (e.g. bagasse), bamboo, bast fibers (e.g. jute, flax, sheep) , Hemp, linen and ramie, leaf vein fibers, etc.), as well as combinations comprising one or more of the cellulosic pulp fibers described above.

In one embodiment of the invention, the cellulosic pulp fibers may be wood pulp fibers. Suitable wood stocks for wood pulp fibers include softwood stocks such as pine, spruce, North American pine and fir, and hardwood stocks such as eucalyptus, poplar, beech, alder, oak and aspen Include, but are not limited to. Possible wood types include, but are not limited to, southern hardwood kraft, eucalyptus wood kraft, northern wood kraft, and the like, as well as combinations comprising one or more of the foregoing. Preparation of suitable wood pulp fibers using a variety of methods including, but not limited to, chemical methods such as kraft and sulfite processes, thermomechanical methods, chemical thermomechanical methods, and one or more of the methods described above can do. Useful methods for making pulp fibers are described in US Pat. No. 5,348,620 to Hermans et al .; U.S. Patent 5,501,768 to Hermans et al .; And dispersing to impart curls and improve dryness, as disclosed in US Pat. No. 5,656,132 to Farrington, Jr. et al.

Some or all of the cellulosic pulp fibers are pretreated with a thermoplastic resin (e.g., a thermoplastic resin having properties that are water soluble, water-dispersible or a combination thereof) before, during or after performing the drying step of the pulp fiber processing process. can do. As used herein, the term “thermoplastic resin” refers to a crystalline or amorphous polymer that softens upon exposure to heat and returns to its original state upon cooling to room temperature. As used herein, the term "water-soluble" refers to a solid that forms a homogeneous aqueous solution at temperatures of about 100 ° C. or less, more particularly about 70 to about 100 ° C., when the thermoplastic resin is present at a concentration of at least 1% by weight of the total solution. Or liquid.

In order for the thermoplastic resin to be used in processing and forming pretreated cellulosic pulp fibers, the thermoplastic resin may have a glass transition temperature of about 50 ° C. or less, more particularly about 25 ° C. or less, even more particularly about −5 ° C. or less. Can be. The thermoplastic resin can optionally have a molecular weight that is high enough to allow the thermoplastic resin to be deposited on the outer surface of the cellulosic pulp fibers, or more specifically, up to about 5% by weight of the thermoplastic resin, based on the total weight of the thermoplastic resin, It may have a molecular weight high enough to allow deposition in the pores of the adult pulp fibers. For example, the thermoplastic resin may have a weight average molecular weight (Mw) of at least about 1,000 atomic mass units (amu), more particularly at least about 10,000 amu, even more particularly at least about 100,000 amu.

Exemplary thermoplastics include polyesters, polyurethanes, polyethylene-co-vinyl acetates, polyvinyl acetate-co-vinyl alcohols, polyacrylates, polyvinyl ethers, polyamides having water soluble, water-dispersible and combinations thereof. As well as combinations comprising one or more of the thermoplastic resins described above.

The amount of pulp fibers pretreated with the thermoplastic resin depends on the type of tissue product to be produced, the desired structural integrity of the tissue product, and the location of the pretreated pulp fibers in the tissue product. In one embodiment of the invention, the tissue product may comprise pulp fibers optionally pretreated with a thermoplastic. As used herein, the term "pretreated" means that the thermoplastic is applied to the pulp fibers during pulp manufacturing. Examples suitable for the present invention are described in US Pat. No. 6,582,560 to Runge et al., Which describes the addition of additives in the manufacture of pulp sheets. The pretreated pulp fibers are then transferred to a different manufacturing process where they are diluted, reslurried and made into fibrous structures. The use of water-soluble or water-dispersible thermoplastics facilitates the reslurrying process.

Pretreatment of the pulp fibers with these thermoplastic resins gives the resulting fibrous structure unique properties, as opposed to the traditional addition of chemical additives to the papermaking water phase. Although not theoretically supported, it is believed that the pretreatment improves the holding power of the thermoplastics by better retaining the material as the fibers are partially coated by the thermoplastic. The coating interferes with the natural bonding of the cellulosic fibers during drying and converts these bonds into less intense thermoplastic bonds.

Tissue products comprising pretreated pulp fibers (eg, fibrous tissue webs, etc.) range from about 1: 5 to about 1: 1,000, more particularly from about 1:10 to about 1: 500, even more particularly about 1:25. And a weight ratio of thermoplastic resin to cellulosic pulp fibers of from about 1: 200.

Pulp fibers can be pretreated with thermoplastics in a variety of ways, such as in wet laid processes. In one embodiment of this invention, this process comprises mixing pulp fibers and water to form a pulp fiber slurry. The pulp fiber slurry can be transferred to a paper-making apparatus of a paper machine to form a wet fibrous tissue web. The wet fibrous tissue web is dewatered to a predetermined consistency to form a dehydrated fibrous tissue web. Chemically pretreated and dehydrated, containing chemically pretreated pulp fibers, by converting the thermoplastic into liquid form (e.g., heated or dispersed and / or dissolved in water, etc.) and adding to the dehydrated fibrous tissue web. To form a fibrous tissue web. Such chemically pretreated pulp fibers can have an increased or improved retention of water-insoluble chemical additives throughout the papermaking process. In another embodiment of the invention, the process may additionally or alternatively comprise adding a thermoplastic resin to the pulp fibers in the pulp processing step.

Possible tissue products comprising pretreated pulp fibers include, but are not limited to, bath tissues, cosmetic tissues, towels, wet tissues, table towels, and the like.

In one embodiment of the invention, the fibrous tissue web is made of a tissue product. The tissue product may be a single or multi-ply tissue product, for example the tissue product may be a three-ply cosmetic tissue product. Cosmetic tissues, bath tissues and towel products as used herein differ in bulk from other paper products. The bulk of the tissue product can be calculated as the quotient of the caliper (micrometer) (defined later) divided by the basis weight (grams per square meter, g / m 2). The bulk thus calculated can be expressed in cubic centimeters per gram (cm 3 / g). Premium letter paper, newsprint and other such paper products typically have higher strength, stiffness and density (lower bulk) compared to tissue products that tend to have much higher calipers for a given basis weight. The tissue product may have a bulk of at least about 2 cm 3 / g, more particularly at least about 2.5 cm 3 / g, even more particularly at least about 3 cm 3 / g. The basis weight of the tissue product may be about 5 to about 200 g / m 2, more particularly about 7 to about 150 g / m 2, even more particularly about 10 to about 100 g / m 2.

The tissue product may comprise a layered and / or blended fibrous tissue web. As used herein, “blended fibrous tissue web” refers to a process of blending various types of pulp fibers prior to forming the fibrous tissue web. According to some embodiments of the present invention, the pretreated pulp fibers may be blended with the untreated pulp fibers prior to forming the fibrous tissue web. In one embodiment of the present invention, the fibrous tissue web may comprise a layer of cellulosic pulp fibers having pulp fibers optionally pretreated with a thermoplastic resin, for example the center of the fibrous tissue web may be a thermoplastic resin on one side. Can be coated. Such structures can generally increase the structural integrity of the fibrous tissue web in areas of higher stress. In another embodiment of the invention, the entire area of the fibrous tissue web, such as the central portion of the fibrous tissue web, may comprise pretreated pulp fibers. In other words, all or part of the fibrous tissue web may comprise a thermoplastic resin. In another embodiment of the present invention, a fibrous tissue web comprising pretreated pulp fibers may be disposed adjacent to and / or between fibrous tissue webs of untreated pulp fibers. For example, a fibrous tissue web comprising from about 25 to about 100 weight percent of pretreated pulp fibers (based on the total weight of the fibrous tissue web) may be up to about 25 weight percent based on the total weight of the particular fibrous tissue web, More particularly about 10 wt% or less, even more particularly about 5 wt% or less may be disposed between fibrous tissue webs comprising pretreated pulp fibers. In another embodiment of the present invention, a concentration gradient of pretreated pulp fibers in the fibrous tissue web is formed across the layer of fibrous tissue web, with higher stressed regions having higher concentrations. For example, the concentration gradient may increase from the edge of the fibrous tissue web toward the center of the fibrous tissue web.

A method of imprinting fibrous tissue webs and / or tissue products (which may have a dense and relatively less dense network of imprints, for example against an drum dryer by means of an imprinting fabric), Various tissue making methods can be used, including wrinkle and non-wrinkle methods. For example, production of fibrous tissue webs and / or tissue products can be carried out in paper machines by mixing dried pretreated pulp fibers with water to form pretreated pulp fiber slurries. Unpretreated pulp fibers may optionally be added to the pretreated pulp fiber slurry to form a blended pulp fiber slurry. The pretreated pulp fiber slurry or blended pulp fiber slurry can then be transferred to a headbox and deposited on a moving wire or belt (hereafter belt), dehydrated, dried and processed to form a fibrous tissue web.

Optionally, additional pulp fiber slurries comprising untreated pulp fibers may be prepared in the same manner as pretreated pulp fiber slurries. The pulp slurry can then be transferred separately or separately to a multilayer headbox, where it can be deposited on a moving belt to form a fibrous tashweb. The fibrous tissue web can be dehydrated, dried, and processed to form a layered, dried fibrous tissue web. For example, a wet fibrous tissue web (prepared by a method of depositing an aqueous pulp fiber slurry from a headbox onto a moving belt to filter pulp fibers and forming an initial fibrous tissue web), such as in a wet laid papermaking process. It may be dewatered using a combination comprising one or more of the processes described above as well as a pressure reduction box, a wet press, a drying apparatus and the like. Examples of known dewatering and other operations of the papermaking process are described in US Pat. No. 5,656,132 (Farrington, Jr. et al.), US Pat. No. 5,598,643 (Chuang et al.) And US Pat. No. 4,556,450 (Chuang et al.). Other examples of possible drying methods include drum drying, aeration drying, steam drying (eg superheated steam drying), displacement dewatering, Yankee drying, infrared drying, microwave drying, radio wave drying, differential gas Combinations including but not limited to pressure drying, impulse drying and the like, as well as the drying methods described above. Some exemplary paper machines are disclosed in US Pat. No. 5,230,776 (Andersson et al.).

Optionally, the fibrous tissue web and / or tissue product may have a design, for example, the fibrous tissue web and / or tissue product may be embossed to have a design and / or the design may be applied to the fibrous tissue web and / or tissue product. Can be. In one embodiment of the present invention, the pretreated pulp fibers can be bonded to one another when exogenous stresses (eg, heat, pressure, etc.) are applied (eg, to the fibrous tissue web comprising such pulp fibers). .

The invention is further illustrated by the following non-limiting examples. The following test method was used in the examples.

The dry tensile index or tensile index of the resin paper strip samples described in the Examples was determined by performing a dry tensile test on a 1 inch wide paper strip. The paper strip sample was placed in a tension frame of 5 inches of gauge length. A 0.5 inch / minute tensile force was then applied to the paper strip sample, and the resulting stress was recorded using a suitable load cell. The maximum load force divided by the width of the sheet strip sample was recorded as the tensile index after normalization to the basis weight of the sheet strip sample. The tensile index is expressed as Newton meter / gram (Nm / g). The tensile force received until the paper strip sample attained maximum load was recorded as the stretchability of the paper strip sample. Extensibility is expressed as a percentage of test length. The slope (kg force kgf) represents the maximum stress-tensile force slope recorded by the test during the first 5% of the tensile force. Absorbed tensile energy (TEA, joules / square meter, J / m 2) is the integrated area of the stress-tension curve divided by the area of the paper strip sample tested.

The wet tensile index was determined by performing a wet tensile test similar to the dry tensile test on a 1 inch paper strip sample, in which the wet strip index was made into rings and the ring bottoms of these strip paper samples were removed at room temperature. By contacting the ionized water, the paper strip sample was well wetted. The ring of resin strip strip sample was left intact until the wetted area was enlarged to 1 to 1.5 inches in the longitudinal direction and uniform throughout the width of the resin strip strip sample. Excess moisture was removed from the paper strip sample by briefly contacting the wet area of the paper strip sample with the blotter paper once. The wet tensile index (Nm / g), which is the maximum load force divided by the width of the wet paper strip sample, was recorded. The wet / dry ratio was obtained by dividing the wet tensile index by the dry tensile index.

Example 1

This example describes a method of making a paper strip sample. By diluting the pulp fiber sample to 1.2 wt% consistency with water in a British Pulp Disintegrator (commercially available at Lorenzen and Wettre, Atlanta, GA), A paper strip sample was prepared having a basis weight of grams per square meter (g / m 2). The pulp fiber sample was immersed for 5 minutes, then pulped for 5 minutes at room temperature (ie about 25 ° C.), diluted to a consistency of 0.3 wt%, and manufactured by Boyce Incorporated, Appleton, Wis. The paper was made from a 9 inch by 9 inch Valley Handsheet Mold (available commercially from Voith Inc.). The paper was removed from the mold by hand using blotter paper and pressed with the wire side facing up for 1 minute at 100 psi. Sheets were made of a Valley Steam Hotplate (commercially available from Boyce Incorporated, Appleton, WI) and tubes (4.75 lbs.) Loaded to maintain a constant tension at one end. Using a standard load canvas cover with the wire side up, dried to absolute dry level for 2 minutes. The sheet thus obtained was then conditioned in a humidity controlled room (23 ° C. and 50% relative humidity) prior to making and testing a sheet of paper strip.

Example 2

A first set of bleached northern softwood kraft pulp fibers comprising 1,000 grams per square meter (g / m 2) sheet of dry pulp fibers was immersed in water and dried to provide a control for the paper strip sample experiment (hereafter referred to as the control). 1)). These pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. A resin strip strip sample, Control 1, was tested for tensile properties following the procedure described above.

Example 3

A second set of bleached northern softwood kraft pulp fibers is trademarked Eastman AQ 38D Copolyester (commercially available from Eastman Chemicals, Kingsport, Tennessee, USA). Pretreated with dispersed sulfonated polyester polymer. This treatment included immersing 1,000 g / m 2 dry pulp fiber sheet in the solution and drying the pulp fibers. Solids of the dispersion were adjusted to provide a 1% throughput based on the dry weight of the pulp fibers. These pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. The paper strip sample (hereinafter referred to as sample 1) was tested for tensileness according to the procedure as described above.

Example 4

Further, a subset of the papermaking strip samples of Sample 1 described in Example 3 was subjected to steel-to-steel at 100 ° C., a pressure of 120 pounds per linear inch and a line speed of about 25 feet per minute (ft / min). Hot-calendar was performed using a (steel-to-steel) calendar. Hot-calendered paper strip samples (hereinafter referred to as sample 2) were tested for tensileness according to the procedure as described above.

Example 5

A third set of bleached northern softwood kraft pulp fibers was pretreated with a dispersed sulfonated polyester polymer named Eastman AQ 38D Copolyester. This treatment included immersing 1,000 g / m 2 dry pulp fiber sheet in a thin dispersion and drying the pulp fibers. Solids of the dispersion were adjusted to provide a 2% throughput based on the dry weight of the pulp fibers. These fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. The paper strip sample (hereinafter referred to as sample 3) was tested for tensileity according to the procedure as described above.

Example 6

Further a subset of the papermaking strip samples obtained in Example 5 was hot-calendered using a steel-to-steel calendar at 100 ° C., a pressure of 120 pounds per linear inch and a line speed of about 25 ft / min. It was. Hot-calendered paper strip samples (hereinafter referred to as sample 4) were tested for tensileness according to the procedure as described above.

The properties of Samples 1-4 as well as Control 1 are listed in Table 1.

Properties of Pretreated Pulp Property Counterpart 1 Sample 1 Sample 2 Sample 3 Sample 4 Dry tensile index (Nm / g) 21.38 20.93 26.56 23.45 38.45 Elongation (%) 1.56 2.35 2.17 2.88 3.13 TEA (J / ㎡) 15.02 21.42 23.17 24.68 35.67 Slope (kgf) 456 386 274 322 254 Wet Tensile Index (Nm / g) 1.23 1.84 2.54 1.95 8.32 Wetting / drying ratio (%) 5.8 8.8 9.6 8.3 21.6

The results specified in Table 1 show that the strength and extensibility of the paper strip samples Samples 1 to 4 increase and the slope decreases upon addition of copolyester, especially after hot-calendering. As can be seen from Samples 1-4, the water-soluble and / or water-dispersible thermoplastics and cellulosic pulp fibers of the present invention can be used to prepare tissue products and / or fibrous tissue webs having the following properties: have:

(i) at least about 2% elongation, more particularly at least about 2.25%, even more particularly at least about 2.5%;

(ii) at least about 1.5 Nm / g, more particularly at least about 1.8 Nm / g, the wet tensile index before hot-calendering, and at least about 2.5 Nm / g, more particularly at least about 5 Nm / g, hot-calender Wet tensile index after ring;

(iii) at least about 8%, more particularly at least about 9%, even more particularly at least about 15% of wet / dry ratio;

(iv) at least about 21 J / m 2, more particularly at least about 23 J / m 2, even more particularly at least about 30 J / m 2 TEA; And / or

(v) a slope of about 400 kgf or less, more particularly about 350 kgf or less, even more particularly about 300 kgf or less.

Example 7

A first set of bleached eucalyptus kraft pulp fibers comprising 1,000 g / m 2 dry pulp sheet was immersed in water and dried to prepare a control (referred to as Control 2 below) for the paper strip sample experiment. . These pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. A resin strip strip sample, Control 2, was tested for tensile properties following the procedure described above.

Example 8

A second set of bleached eucalyptus kraft pulp fibers was pretreated with a dispersed sulfonated polyester polymer (Eastman AQ 38D copolyester). This treatment included immersing 1,000 g / m 2 dry pulp fiber sheet in a thin dispersion and drying the pulp fibers. Solids and addition volume of the dispersion were adjusted to provide a 5% throughput based on the dry weight of the pulp fibers. The pretreated pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. The paper strip sample (hereinafter referred to as sample 5) was tested for tensileness according to the procedure as described above.

Example 9

A third set of bleached eucalyptus kraft pulp fibers was pretreated with a polyurethane polymer named Permax 120 (commercially available from Noveon, Cleveland, Ohio). This treatment included immersing 1,000 g / m 2 dry pulp fiber sheet in a thin dispersion and drying the pulp fibers. Solids and addition volume of the dispersion were adjusted to provide a 5% throughput based on the dry weight of the pulp fibers. The pretreated pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. The paper strip sample (hereinafter referred to as Sample 6) was tested for tensileness according to the procedure as described above.

Example 10

A fourth set of bleached eucalyptus kraft pulp fibers was pretreated with a vinyl acetate polymer named Vinac 911 (commercially available from Air Products, Allentown, PA). This treatment included immersing 1,000 g / m 2 dry pulp fiber sheet in a thin dispersion and drying the pulp fibers. Solids and addition volume of the dispersion were adjusted to provide a 5% throughput based on the dry weight of the pulp fibers. The pretreated pulp fibers were slurried and made into standard paper and ultimately paper paper strip samples, as described in Example 1. The paper strip sample (hereinafter referred to as sample 7) was tested for tensileness according to the procedure as described above.

The properties of Control 2 and Samples 5-7 are specified in Table 2.

The nature of the sheet Property Counterpart 2 Sample 5 Sample 6 Sample 7 Dry tensile index (Nm / g) 13.5 19.5 13.0 16.9 Elongation (%) 1.3 2.5 3.0 2.9 TEA (J / ㎡) 3.5 9.5 5.9 7.9 Slope (kgf) 375 254 284 301 Wet Tensile Index (Nm / g) 1.1 3.5 2.9 3.6 Wetting / drying ratio (%) 8.1 18.0 22.3 21.3

The results indicated in Table 2 indicate that samples 5-7, which are paper strip samples containing pulp fibers pretreated with the thermoplastic resin of the present invention, have higher stretchability (at least about 2.00%, more particularly at least about 2.50%), Control 2 is less than about 1.35%), higher wet tensile index (at least about 2.00 Nm / g, more particularly at least about 2.50 Nm / g, even more particularly at least about 3.25 Nm / g, while Control 2 Is less than about 1.15 Nm / g, higher wetting / drying ratio (e.g., at least about 12%, more particularly at least about 15%, even more particularly at least about 20%, whereas Control 2 is about 9% Has a lower slope (eg, about 325 kgf or less, more particularly about 300 kgf or less, even more particularly about 290 kgf or less), while Control 2 is greater than about 370 kgf. Im). While not theoretically supported, it has been found that when the slope is reduced, tissue products and / or fibrous tissue webs with higher strength are formed at lower stiffness, as compared to methods such as refining. This results in fibrous tissue webs and / or tissue products that are less fragile and have higher durability, which is particularly advantageous for soft tissue products.

A third set of papermaking experiments was performed to provide an example of the effect of thermoplastic addition through typical wet addition of polymers. Data for a second grassland experiment on Control 2 was used for this set of experiments.

Example 11

Through wet addition of the Eastman AQ polymer, a fifth set of bleached eucalyptus kraft pulp fibers was prepared as a sample (hereinafter referred to as sample 8) for the paper strip sample experiment. 60 grams per square meter (g / m 2) basis by diluting pulp fiber samples to 1.2 wt% consistency with water in a British pulp disintegrator (commercially available from Lorenchen & Wetre, Atlanta, GA) A weight paper strip sample was prepared. The pulp fiber sample was immersed for 5 minutes, then pulped for 5 minutes at room temperature (ie about 25 ° C.), and diluted to a consistency of 0.3 wt%. A thin dispersion of Eastman AQ 38D copolyester was added to the pulp suspension and mixed for 5 minutes to provide a throughput of about 5% based on the dry weight of the pulp fibers. These suspensions were made of paper in a 9 inch by 9 inch valley handsheet mold (commercially available from Boyce Inc., Appleton, Wis.). The paper was removed from the mold by hand using blotter paper and pressed with the wire side facing up for 1 minute at 100 psi. Standard paper canvas cover with a valley steam hotplate (commercially available from Boyce Inc., Appleton, WI) and a tube (4.75 pounds) loaded to maintain a constant tension on one end Using, with the wire side facing up, it was dried to an absolute dry level for 2 minutes. Sample of this resin strip strip, Sample 8, was tested for tensile properties following the procedure described above.

Example 12

A sixth set of bleached eucalyptus kraft pulp fibers was prepared through wet addition of a polyurethane polymer named Permax 120 (commercially available from Noveon, Cleveland, Ohio). This treatment was the same as in Example 11, except that instead of Eastman AQ 38D, a dispersion of Permax 120 polymer was used to provide about 5% throughput based on the dry weight of the pulp fibers. The pulp fibers and the polymer were mixed and made into standard paper and ultimately paper paper strip samples, as described in Example 11. This paper strip sample (hereinafter referred to as sample 9) was tested for tensileness according to the procedure as described above.

Example 13

A seventh set of bleached eucalyptus kraft pulp fibers was prepared through wet addition of a polyurethane polymer labeled Vinak 911 (commercially available from Air Products, Allentown, PA). This treatment was the same as in Example 11, except that instead of Eastman AQ 38D, a dispersion of Permax 120 polymer was used to provide about 5% throughput based on the dry weight of the pulp fibers. The pulp fibers and the polymer were mixed and made into standard paper and ultimately paper paper strip samples, as described in Example 11. This resin strip strip sample (hereinafter referred to as sample 10) was tested for tensileness according to the procedure as described above.

The properties of Control 2 and Samples 8-10 are specified in Table 3.

The nature of the sheet Property Counterpart 2 Sample 8 Sample 9 Sample 10 Dry tensile index (Nm / g) 13.5 14.1 13.8 12.5 Elongation (%) 1.3 1.4 1.1 1.3 TEA (J / ㎡) 3.5 4.1 3.6 3.1 Slope (kgf) 375 386 412 391 Wet Tensile Index (Nm / g) 1.1 1.0 1.1 1.0 Wetting / drying ratio (%) 8.1 7.1 8.0 8.0

The results specified in Table 3 show that samples 8 to 10, which are paper strip samples containing pulp fibers treated with thermoplastics in the wetted parts, have properties very similar to the control. This example demonstrates the utility of the pretreatment step of the present invention to provide unique tensile, stretch and modulus of elasticity.

Cellulose pulp fibers, tissue products, and methods using cellulosic fibers and water-soluble and / or water-dispersible thermoplastics are characterized in that the fibrous tissue web and Improve the properties of the tissue product. Fibrous tissue webs and / or tissue products comprising a layer of pretreated cellulosic pulp fibers and / or pretreated cellulosic pulp fibers are durable to fibrous tissue webs and / or tissue products comprising such pretreated cellulosic pulp fibers. Has a dry and wet strength to impart. In addition, the process of the present invention allows the pretreated cellulosic pulp fibers to be selectively present in the fibrous tissue web and / or tissue product, thereby achieving the desired structural integrity of the fibrous tissue web and / or tissue product. Softness, for example). In addition, the thermoplastic resins of the present invention are water soluble and / or water-dispersible, so that the fibrous tissue webs and / or tissue products can be easily recycled, in particular repulped.

The disclosure of the invention has been described with reference to exemplary embodiments of the invention, and those skilled in the art will understand that various changes may be made and equivalents may replace elements thereof without departing from the scope of the disclosure. . In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Thus, while the present disclosure is not limited to specific embodiments of the present invention, it has been disclosed as the best mode devised to practice such disclosure, but the present disclosure includes all embodiments of the invention that fall within the appended claims. something to do.

Claims (22)

Cellulosic pulp fibers; And Pretreated cellulosic pulp fibers formed by pretreatment of cellulosic pulp fibers with a thermoplastic resin having properties selected from the group consisting essentially of water-soluble, water-dispersible, and combinations thereof Fibrous tissue web comprising a. A fibrous tissue web comprising pretreated cellulosic pulp fibers formed by pretreatment of cellulosic pulp fibers with a thermoplastic resin having properties selected from the group consisting essentially of water-soluble, water-dispersible, and combinations thereof. The fibrous tissue web of claim 1, wherein the thermoplastic resin is present in an amount of from about 0.1 to about 20 weight percent based on the total weight of the fibrous tissue web. The fibrous tissue web of claim 1, wherein the thermoplastic resin is present in an amount of from about 0.5 to about 10 weight percent based on the total weight of the fibrous tissue web. The fibrous tissue web of claim 1 or 2, wherein the cellulosic pulp fibers comprise wood pulp fibers. 3. The thermoplastic resin of claim 1, wherein the thermoplastic resin is polyurethane, polyethylene-co-vinyl acetate, polyvinyl acetate-co-vinyl alcohol, polyester, polyacrylate, polyvinyl ether, polyamide, and one described above. A fibrous tissue web selected from the group consisting essentially of combinations comprising at least thermoplastic resins. The fibrous tissue web of claim 1 or 2, wherein the fibrous tissue web is a wet laid fibrous structure. The fibrous tissue web of claim 1, wherein the fibrous tissue web is hot-calendered. The fibrous tissue web of claim 1 or 2, wherein the thermoplastic resin substantially completely coats the pretreated cellulosic pulp fibers. 3. The fibrous tissue web of claim 1 or 2, wherein the thermoplastic resin at least partially coats the pretreated cellulosic pulp fibers. The fibrous tissue web of claim 1 or 2, wherein the weight ratio of thermoplastic resin to pretreated cellulosic pulp fibers is from about 1: 5 to about 1: 1,000. Comprising cellulosic pulp fibers, A pretreated cellulosic pulp fiber formed by pretreatment of cellulosic pulp fibers with a thermoplastic resin having properties selected from the group consisting essentially of water-soluble, water-dispersible, and combinations thereof. 13. The pretreated cellulosic pulp fiber of claim 12 wherein the thermoplastic resin is present in an amount of from about 0.1 to about 20 weight percent, based on the total weight of the pretreated cellulosic pulp fiber. 13. The pretreated cellulosic pulp fiber of claim 12 wherein the thermoplastic resin is present in an amount of about 0.5 to about 10 weight percent based on the total weight of the pretreated cellulosic pulp fiber. 13. The pretreated cellulosic pulp fiber of claim 12 comprising wood pulp fibers. 13. The thermoplastic resin of claim 12 wherein the thermoplastic resin comprises polyurethane, polyethylene-co-vinyl acetate, polyvinyl acetate-co-vinyl alcohol, polyester, polyacrylate, polyvinyl ether, polyamide, and at least one thermoplastic resin as described above. A pretreated cellulosic pulp fiber selected from the group consisting essentially of comprising blends. 13. The pretreated cellulosic pulp fiber of claim 12 wherein the thermoplastic resin substantially completely coats the pretreated cellulosic pulp fiber. 13. The pretreated cellulosic pulp fiber of claim 12 wherein the thermoplastic resin at least partially coats the pretreated cellulosic pulp fiber. 13. The pretreated cellulosic pulp fiber of claim 12 wherein the weight ratio of thermoplastic to pretreated cellulosic pulp fibers is from about 1: 5 to about 1: 1,000. Treating the cellulosic pulp fibers with a thermoplastic resin having properties selected from the group consisting essentially of water-soluble, water-dispersible, and combinations thereof to form pretreated cellulosic pulp fibers; Forming a fibrous tissue web consisting of pretreated cellulosic pulp fibers; Drying a fibrous tissue web to produce a tissue product Including, tissue product manufacturing method. The method of claim 20, wherein the thermoplastic resin is present in an amount from about 0.1 to about 20 weight percent based on the total weight of the fibrous tissue web. 22. The method of claim 21, wherein the thermoplastic resin is present in an amount from about 0.5 to about 10 weight percent based on the total weight of the fibrous tissue web.