DE2508762A1 - CELLULOSE FIBERS IMPRAEGNED INSIDE WITH A WET RESISTANT RESIN - Google Patents

Description

RECHTSAMV / ÄTE a- -.

DR. JMi ϊ.Γ:.-C-ΠΜ. WALTER BEÄ - 27. ΓβΟ.

DR. JV: ·, ■ - ?. V-

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623 f kaHK; ί-Λ · Γ .Λ, ν, / ViAäK-ttü

Our no. 19 728

She Buckeye Cellulose Corporation Cincinnati, Ohio, V.St.A.

Cellulose fibers that are internally impregnated with a resin that provides wet strength

In the patent application filed today (our no. 19 729) twisted cellulose fibers are used described, which are modified and stiffened by essentially internal impregnation with wet strength resins. the Fibers impregnated with wet strength resin are twisted Strand form of cellulose fibers dried without constriction; they can also be made of fibers. those when they are incorporated, impart desirable properties such as softness, absorbency, porosity and resilience.

The present invention relates to the provision of un-

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. twisted strand fibers which have the physical appearance of paper fibers dried as a flat structure, the fibers according to the invention being modified and stiffened by essentially internal impregnation with wet strength resins. The invention also relates to methods of manufacturing un twisted. '(Untwistesl) ,,,; . >"'.".·' . _Λ ^: inside with

gellulo ^ estrang- / (ribbon fibers) wet strength resin impregnated, lasered and ^a :! - ^e use of these fiber materials in products with increased absorbency, softer feel, increased wick speed, larger volume, improved porosity and improved compression resistance or bounce in the wet or dry state. The fibers according to the invention, impregnated with wet strength resin, develop after slurrying, shaping and renewed drying during the production of flat structures from unground fiber slurry. no hydrogen bonds between the fibers, and they do not produce sheets with discernible wet strength properties. If the fibers according to the invention, internally impregnated with wet strength resin, are slurried again after drying and hardening in the course of the original production, shaped into paper-like flat structures and dried, then expand. ^X under SxTSang a fluffy mat, which is similar to mats produced without a binder, which are obtained by laying dry cellulose fibers with air. Expansion can be limited and a degree of paper-like bonding can be achieved by carefully grinding or refining the resin impregnated fibers in a paper machine.

Ea it was found that cellulose fibers after impregnation in the Inside with wet strength resins, washing off the wet strength resin of the outer surfaces and drying with curing of the resin as regards very desirable and surprising changes the physical and chemical fiber properties which are important for numerous uses.

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Although the inside was impregnated with wet strength resin Fibers can dry and harden in any amount after washing the outer fiber surfaces, there is a two-dimensional and The preferred method is to shape them into a sheet structure before drying and hardening. This flat structure from the fibers according to the invention is physically similar to a material web in conventional paper production, and it is surprising that re-slurried fibers no more hydrogen bonds from this fabric form. The inside impregnated with wet strength resin and fibers produced according to the invention achieve a unique combination of physical and chemical properties, which increases in fiber stiffness, increases / f'asej? *

- j.- . m ffcibhon fiber) and fiber structures, -. Characteristic fiber form, reduced swellability iai water, reduced solubility in conventional cellulose solvents, inability to form typical fiber bridges in papermaking processes, desired networkability and increased biodegradability. The fibers impregnated with wet strength resin resist hydration during grinding and finishing in the course of papermaking, but tolerate this treatment and are not significantly degraded as a result.

The different properties of the fibers according to the invention, internally impregnated with wet strength resin, make them Particularly useful for numerous applications, for example for the absorption of liquids, for the filtration of Liquids, for cushioning, insulation and volume filling. Of the The range of properties for special applications can be set by selecting the cellulose fiber, type and Extent of wet strength resin impregnation and manufacturing of mixtures of resin-impregnated fibers and untreated Fibers and other materials.

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The present invention relates to impregnation of dried or never dried cellulose fibers any of natural origin with wet strength hair. The advantages of the process according to the invention occur both with unbleached, semi-bleached or fully bleached fibers, regardless of the method of fiber insulation. The bleached ones or unbleached fibers from cotton or egrained tree— Wool seeds are particularly suitable for impregnation with wet strength resin according to the invention.

The use of wet strength resins to improve the Dry and wet strength of two-dimensional paper products th is well known, in the known cases the function of the polymeric resin in increasing the extent of the There is a bond between the fibers in the paper web. So are for example processes for the production of wet strength papers known, in which colloidal melamine resin is added to the paper pulp of the paper machine, see G. G. Landes and CA. Maxwell, Paper Trade Journal, Vol. 121, p. 51, (1-945). the US-PS 2,595,935 describes a process for the production of paper with wet and dry strength properties, which improved, thermosetting resins used, which are obtained by condensation of an alkaline polyamine with a halohydrin «In this case, the wet strength resin applied in a conventional manner with application to the slurried fibers, which are then formed directly into the paper web and dried, or by application to wet preformed paper which is then dried to form wet strength paper.

In the paper industry it is common to use wet strength resin Coated fibers from old waste in smaller quantities to start again in the cycle. With this waste recycling

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a problem arose in reslurrying, so that Methods for reslurrying the wet strength treated Waste had to be worked out. Mechanical fiberization is generally seen as an undesirable cost factor in the manufacture of wet strength papers. With conventional mechanical defibration, fiber damage also occurs and fiber shortenings, which further reduce the value of the processed fibers. The realization These disadvantages of the mechanical methods for defibrating wet-strength papers have stimulated research, To develop wet strength resins that can be inactivated by chemical processes, thereby reducing the processing of fibers made of paper treated with wet strength resin for the purpose reintroduction into papermaking is facilitated. Such efforts have not produced any noteworthy results.

The chemical cross-linking of the inner elements of cellulose fibers is well known, see, for example, U.S. Patents 3,224,926, 3,241,553, and 3,653,612. These patents describe processes for the production of cross-linked cellulose fiber products and ",. Qe "bjLld.en beziv. .

their use in different / structures. The networking process work with relatively small molecules that penetrate into the small spaces within the cellulose fibers, whereby cross-linking creates inelastic connections between cellulose molecules and nearby hydroxyl groups by covalent Bonds are created.

US Pat. No. 3,756,913 describes a process with a special sequence of steps which results in the cellulose fibers appearing on the outside with nouns polymeric compounds called wet strength resins to serve, . are coated. This outer covering of the fibers differs from that of the invention Impregnation of the fibers inside with wet strength resins.

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In contrast to the known processes for the production and use of modified and wet-strength cellulose fibers and structures containing them, it has now been found that fibers impregnated with wet-strength resin inside, which are washed before drying and hardening, so that practically no bonds of the Wet strength resin between the fibers during manufacture and first drying and. Develop hardening, possess exceptional absorbency and elasticity. The properties to be measured against the results obtained to wet during processing and dry webs, or the formation of cushions, and which manifest themselves in particular in absorbent ^r Gebildeni of these fibers. It should be noted that the fibers form during the first drying and curing hydrogen bonds, but surprisingly neither hydrogen bonds nor bonds between fiber and wet strength show when they are slurried and transforms new Faser'gebilden \.

The aim of the invention is thus to provide fibers with the characteristic ribbon-like appearance of cellulose fibers, which are internally impregnated with wet strength resins. The aim of the invention is also to provide a method by which wet strength resin impregnated fibers can be conveniently and economically manufactured, and Although for the purpose of use in absorbent, elastic, deserving resistant fiber. 'formed' ..

The invention also relates to hardened, internally wet strength resins impregnated fibers in the form of sheets or mats, which have the characteristic duty unpaid. .10im have and which can be subjected to wet or dry shaping to form a highly absorbent sheet low density and high bounce.

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According to the invention, fibers which are essentially impregnated internally with wet strength resin are produced which are characterized by improved properties, such as, for example, increased wicking rate in fiber structures or formations, improved bounce and increased volume, increased swelling ^ l'iiii ^ B ¹¹¹¹ ^^ hydrogen bonds in fiber structures made from them. According to the invention, cellulose fibers are slurried in water and the pH of the slurry is increased to increase the fiber swelling, then wet strength resin is added, with mixing and dipping continued at the pH which improves the fiber quality, in order to impregnate the inner fiber surfaces and voids with the To increase wet strength resin. The pH is then lowered to a value that promotes fiber contraction and. the polymerisation of the wet strength resin promotes further mixing and immersion. The fiber slurry is then dewatered into a mat or web, then the outer surfaces of the fibers are washed free of the resin solids, and simultaneously with the drying of the fibers, the heat curing of the wet strength resin takes place. Further process steps can be used to add flame retardant compounds or dyes or to condition the fiber products mechanically or chemically for special uses. The method according to the invention generates a new one. Ribbon fiber made of cellulose, which is essentially only incorporated into the inside polymerized wet strength resin. The fiber products give it on dry or wet way

4.TT ^. τ- 4.4. j -du ττ ·· ί ^{η the} ^ S ^ jP ^ P ΧΆ. For example, mats or lanes provided in the form of high, increased! Fencing effect and jumping power and the absence of hydrogen bonds.

According to the invention, the interior is impregnated with wet strength resin Cellulosic fibers are produced by a process the essential stages of which are that of an initial impregnation with wet strength resin in a fiber slurry higher pH, which promotes fiber swelling, and at two

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In the first place, fiber contraction and polymerisation of the wet strength resin at lower pH, causing the pastes of wet strength resin solids Washed free on their outer surfaces and then dried with hardening of the wet strength resin will. The process stages are dealt with in detail below:

Ό slurrying the cellulose fibers; It was found that

Cellulose fibers of various natural origin, preferably cooked and never dried fibers, in unbleached, partially bleached or completely bleached state ^ made of hard or soft woods or cotton linters, can be supplied to the method according to the invention. Dried Fibers of the above origin as well as never dried and dried fibers made from esparto grass, bagasse, hemp, flax, or other woody and cellulose fiber sources can be used as raw materials be used.

These fibers are impregnated inside with the wet strength resin, by first slurrying them in v / water at a concentration of about 0.3 to about 2.5 and preferably about 2 $, to pre-swell the fibers for the impregnation disperse and condition. It was found advantageous to check the fiber concentration in the aqueous slurry set to about $ 2 to allow the wet strength resin transition is improved in the Pasern. Higher concentrations the fiber slurry increase the wet strength resin pick-up by the paser provided that effective movement of the mass is maintained.

2) Adding the wet strength resin pesticides at the pH of the

Paser swelling; After the fiber suspension has been prepared according to step 1, a dilute solution of the wet strength resin is added to the fiber suspension. Aqueous solutions are preferred, but solutions of wet strength

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Use keitsharaes in suitable organic diluents. The resulting slurry is then carefully

• Effectively mixed or immersed in order to ensure contact with the Emzel fibers before an EMC period of the fiber slurry, the penetration and impregnation of the fibers by the high strength resin ensures.

When adding the dilute solution of the wet strength resin the pH of the slurry is adjusted to about 5 to about 11, according to the pH properties of the wet strength resin used. Suitable pH values at this stage of adding the wet strength resin are, for example, 10

-hardening
for neutral resins, 7 for urea / formaldehyde resins and 5 for kelamin / formaldehyde resins. The pH value is adjusted with sodium hydroxide or other chemicals in such a way that the highest possible pH is achieved without precipitation of wet strength resin, promotes fiber swelling and the penetration and deposition of the wet strength resin on the inner cavity surfaces of the cellulose fibers. All types of wet strength resins can be used in accordance with the invention, including urea / formaldehyde resins, melamine / formaldehyde resins, polyamide / polyamine / epichlorohydrin resins, polyethyleneimine and cationic dialdehyde starch resins.

About 5 to about 50% wet strength resin solids based on the weight of fibers in the slurry are added to the slurry of cellulosic fibers in the form of a dilute aqueous solution of about 1 to about 15, and preferably about 5 "/ % resin concentration. Larger amounts of wet strength resin are not detrimental to the process, but can lead to difficulties in the recovery of the wet strength resin and uneconomical operation.

The addition of the wet strength resin leads to impregnation

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of the cellulosic fibers inside with about 0.2 to about 6fo or more of chewing resin. Typically, an internal impregnation of the fibers with about 2 to 35 degrees wet strength resin is desired. As already mentioned, additional amounts of wet strength resin and impregnation can lead to somewhat improved fiber products, but they are mostly uneconomical in terms of the improvement in fiber properties achieved. The fiber concentration in the slurry during the treatment with the wet strength resin can also be varied somewhat, whereby intimate contact of the fibers with the wet strength resin must be achieved by agitation.

The wet strength resin is applied in the form of a dilute aqueous or organic solution to prevent penetration into the Increase fibers. Freshly prepared solutions of the wet strength resin, in which wet strength resin solids are smaller colloidal Large sizes are preferred because they increase fiber penetration; however, the penetration is in the Processes working with two pH values are also achieved with resin preparations that have had normal storage times.

In adding the wet strength resin solids to the aqueous fiber slurry you need a mixing and immersion time to ensure an intimate contact between the wet strength resin est ^ fabrics and fibers. 'is sufficient. being found was that with a miseh__zeit of about 15 minutes to about one hour and an additional immersion time of about 30 minutes to about 15 hours, the desired fiber impregnation is achieved. JSs is particularly noteworthy that during the Diving can continue to stir, and that total times of. about 45 minutes to about 16 hours in terms of adding the wet strength resin solids are effective «During mixing and. The fiber slurry is preferably dipped at low temperatures.

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temperature or the temperature created by the mixing, such elevated temperatures reduce the fiber swelling and thereby the desired penetration of the wet strength resin solids decreases into the interior of the laser, lim the swelling of the fibers To increase it further, slightly reduced slurry temperatures from about 10 to about 21 C can be used.

(3) Mixing and dipping in the presence of the wet strength resin solids at the "pH of the resin deposit; after impregnating the slurried cellulose fibers with the wet strength resin at the elevated pH of level 2, the pH of the slurry is lowered, preferably with dilute sulfuric acid ( 10% aqueous sulfuric acid solutions are used to avoid burns of the laser), followed by thorough mixing for about 10 minutes to about 1 hour before another immersion for about 20 minutes to about 15 hours, and preferably ^{1 to} about 1 hour pH Note that stirring can be continued during the dip and that total times of about 15 minutes to about 16 hours are effective, at which point the pH is adjusted to about up to about 2.5, again depending on the pH pH properties of the wet strength resin used It has been found that, for example, the following pH values are effective in this third stage: 7 for neutrally curing resins, 4.5 for urea / formaldehyde resins and 3.2 for melamine / lormaldehyde resins. This mixing and immersion stage is carried out at hardly any temperature. The lowering of the pH leads to fiber contraction and deposition of the impregnating resin inside and on the surfaces of the inner cavities of the cellulose fibers. Lowering the pH value also creates favorable conditions for hardening the wet strength resin. Dilute sulfuric acid solutions are preferred to lower the pH value, but other mineral acids such as hydrochloric acid and organic acids such as acetic acid and acidic salts can also be used.

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(4) Washing the fibers After impregnation with the wet strength resin and its deposition on the cellulose fibers in stages 2 and 3, the impregnated fibers are removed from the vase in the form of a web or mat To facilitate the washing out of the wet strength resin from the outer surfaces of the pasers. This washing can take place in the Fourdrinier section of a paper machine by means of arrangements of spray and vacuum devices operated in stages or in counter-flow.

The washout of the hate resistance resin can also be done by gradual or countercurrent washing on one Vacuum drum washer. JSs was found to be around 20 kg of water per kg of fibers to about 800 kg of water per kg of fibers effectively removes the outer build-up of the strength resin will. When using smaller amounts of water, more effective washing facilities are required. When using larger what- The required removal of the corn strength resin is achieved with these quantities γόη the iPaser external fiäohen, wasted however Water.

(5) dry the fiber and hardness of the wet strength resin;

The washed sheets or mats from inside with wet feet activity resin-impregnated fibers v / earth long? heated that the wet strength resin deposited inside hardens and the fibers dry. If the resin consists of a urea / normaldehyde, sum example from "öaseo PH 335" (Manuf. Borden Chemical Co., Columbus, Ohio) an appropriate drying and curing temperature will be at 116 G. This temperature will be 20 to 30 minutes maintain. Own other wet strength resins, optimal hardening and curing conditions specified by the manufacturer can be specified. The neutral curing resins of the polyamide / polyamine / epichlorohydrin type, for example "Kymene '557" (Manuf. Hercules, Inc., Wilmington, Delaware) can be selected in the fibers

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Hardened for 45 minutes at 121 ° C. It is known to the person skilled in the art that numerous temperature / time relationships with regard to the curing of a wet strength resin consist, in general higher temperatures shorten the curing time, while at normal paper drying temperatures and times and storage before use, the curing of the wet strength resin can achieve. Within the possible Time / temperature relationship takes place the optimal curing of the wet strength resin with the data given by the manufacturer or known from the literature.

The dried and hardened ones resulting from stage 5 Mats or sheets represent the product according to the invention «, “As already mentioned, these products are interrelated. Surprisingly, however, it was found that the fibers in these products, after! drying and hardening, no hydrogen bonds or bonds between fiber and wet strength resin form when they are re-slurried to form various end products ο those produced by the above process, iia have fibers impregnated with ITA strength resin inside the relatively straight ribbon configuration of cellulosic fibers that appears in conventional paper webs in which the fibers are constricted during drying. The fibers of the invention are new in that the Wet strength resins with which they have been impregnated are essentially are deposited inside the fiber walls. These fibers are naturally without hydrogen bonds, and they are in practically insoluble in the usual gupriethylenediamine solution used by industry for testing fibers. The fiber product of the invention also has a surprisingly high wick speed of about 0.7 to 0.9 cm / sec. in bulk or in sheet form and low swelling in water. That Product can be ground in operations in the production of paper

Fiber or refined without significant damage or,

- shortening occurs "

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The to determine the surprising properties, the invention Tests used on fibers, which were also used in the examples below, are as follows carried out:

Wick speed test (v / icking bate)

Fluffy fibers impregnated on the inside with high strength resin are conditioned at 22.2 + 1.1 ⁰ G and 50 + 2 ° iger relative humidity. Mats of 10.16 χ 10.16 cm are made from two roughly equal layers that are placed 180 degrees against each other. These ikatten are pressed between metal surfaces and adjusted so that a sample of 10.16 χ 10.16 cm, 3f30 + 0.10 g weight and 0.250 + 0.015 g / cm density is obtained.

These mats are then clamped vertically in a sample holder, where they bezw by at least two electrodes near the top. touched the lower end. The wicking time begins when contact is made between the electrodes at the lower end ^ and ends when contact between the two upper electrodes is established. The time to ascend (wicking up) on the vertical specimen is determined on 5 specimens and the individual specimen weights and densities , Times and speeds C in. Cm / sec.). The mean wick speed is in cm / sec. calculated.

Drip capacity

To determine the drip capacity, samples are taken as in above Test produced "The mats are placed on a wire netting with square meshes 1.27 cm apart. Water is then allowed to drip onto the center of a mat at a rate of 1 ml / sec. The time that

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the mat needed before it releases the first drop of water from the underside is recorded and the drip capacity is recorded is given in grams of volume per gram of cellulose in the mat.

Wet compressibility and dry compressibility test

The wet compressibility of the fibers impregnated inside with wet strength resin is determined by slurrying the fibers in a TAPPI disintegrator and scooping sheets by hand with a TAPPI device, samples of which are 10.16 10 ₉ 16 μm with a fiber basis weight of about 3.0 g / 103 cm can be cut. The normal samples are then compressed over the entire surface and their bead is measured under the increasing loads of 0, 0.013, 0, u; J5, 0.053 and 0.070 kg / cm ² . Then the wet & atte is dried at 116 ° C and the dry weight is determined. The thickness of the dry mat is measured at 0 and 0.070 kg / cia load. The apparent wet density (g / cm) is determined from the wet thickness at each load and the dry weight of the mat. The dry density (g / cm) is calculated from the dry density and dry weight of the mat.

Example I.

Fibers impregnated inside with wet strength resin produced by first combining never-dried kraft fibers from bleached softwood from the south with a fiber— concentration of $ 0.7 in water slurries. Then $ 25? based on the fiber weight in the slurry, the wet strength resin "Kymene 557H" (polyamide / polyamine / epichlor = hydrin resin, Hercules, Inc., Wilmington, Delaware) with stirring in the form of an aqueous solution containing 5% by weight of wet strength resin solids contains, added. The mixture is stirred for a further 15 minutes, the pH of the fiber suspension during this time and the subsequent dive time of 45 minutes 9

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carries, by adding an aqueous solution containing 5 wt.? o sodium hydroxide. After the immersion time at pH-9, the pH value of the fiber slurry is lowered to 7.5 with 1% sulfuric acid solution. At this lower pH, the fiber slurry is mixed thoroughly and allowed to immerse for 30 minutes. The impregnated fibers are then placed on the sieve of a vacuum drum washer and washed with water in countercurrent, using 50 kg of water / kg of fibers. A sheet is then formed from the washed fibers, followed by i _m oven at 116 ⁰ G is 16 hours. The fiber product according to the invention is obtained in web form. It has an ^e 1iarzgehalt of 2.63 $, based on the fiber weight.

After drying and curing, a quantity of the impregnated fibers is processed into a web in a TAPPI disintegrator slurried in water at a fiber concentration of $ 0.1 and scooped by hand into a sheet with a basic weight of 3 g /

ρ
103 cm. This sheet is wet pressed under a load of 0.07 kg / cm and dried at 116 g. The dried web has a dry density of 0.033 g / cm, measured under the load 0, and a dry density Λοη 0.072 g / cm, measured under the load 0.07 kg / cm. The dry density of identical, but not impregnated fibers is less than the load 0 0.142 g / cm and under the load 0.07 kg / cm 0.161 g / cm ⁵ .

The wet compressibility, expressed as the apparent wet density, was found to be 0.061 g / cm under the 0 load and 0.2fog / cm under the 0.07 kg / cm load. The wet compressibilities of the same fibers without the wet strength resin are 0.081 g / cm ⁵ under the 0 load and 0.168 g / cm ⁵ under the 0.07 kg / cm ² load.

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- ~ I (-

These tests show - in comparison to the untreated fibers the surprising ability of the inside with Naidfasten resin impregnated fibers to produce and. Maintaining volume in fiber jets under wet and dry conditions. The fibers made by the method of Example 1 and other fibers made in accordance with the present invention are therefore suitable and advantageous for the production of paper towels, cuffs, Diaper cores and sheets for paper towels. Following the procedure of Example 1 using a wet strength resin Pipes produced from polyethyleneimine or cationic dialdehyde starch show similarly improved properties. These advantageous properties are also obtained when the procedure of Example I is followed, but washing with 20 kg of water per kg of fibers before drying and Hardening.

Example II

Fibers impregnated internally with wet strength resin are produced by first slurrying never-dried Kraft fibers from bleached softwood from the south in a fiber concentration of 0.7>"° in water. Then 25 / £» based on the fiber weight in the slurry, of the resin "Parez 607" (melamine / formaldehyde wet strength resin, manufactured by American Cyanamid Co., Wayne, New Jersey) in the form of an aqueous solution containing 5% by weight of wet strength resin solids, with stirring stirred for a further 15 minutes. During this time and is the subsequent 45 minutes immersion time, the pH of 5, wherein its setting was made by the addition of an aqueous 5 wt. ° / o of sodium hydroxide solution. After the Sauchzeit at pH 5 is the pH The fiber slurry value is lowered to 3 "2" with 10% sulfuric acid solution At this pH, the slurry is mixed thoroughly and immersed for 50 minutes deposited on a sieve of a vacuum drum washer and

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washed in countercurrent with 50 kg of water per kg of fibers. The washed ones Fibers are forced into a web and placed in a drying cabinet dried and hardened at 116 G for 16 hours, whereby one a fiber product according to the invention is obtained in web form. Of the Resin content is $ 2.03 based on fiber weight.

After drying and hardening, some of the impregnated fibers are placed in a TAPPI disintegrator with a fiber concentration of 0.15S slurried in water and then by hand into one

ο A web scooped with a basis weight of 3 g per 103 cm «This web is pressed under a load of 0.07 kg / cm and dried ^{at 116 ° C.} The dried web has a dry density of 0.036 g / cm under the 0 load and a dry density of 0.030 g / cm under the 0.07 kg / cm load and 0.16 ³ Ig / cm ⁵ at the

Load 0.07 kg / cm determined.

The wet compressibility, expressed as the apparent wet density, of the impregnated fibers becomes 0.059 g / cca below the load stung 0 and to 0.110 g / cm under the load 0.07 kg / cm determined. The wet compressibilities of resin-free fibers are 0.081 g / cm for the load 0 and 0.168 g / cm for the load 0.07 kg / cm. The wick speed of the impregnated fibers is 0.92 cm / sec., The drip capacity 8.3 g water / g fiber. In the case of the non-impregnated fibers, the values obtained are 0.58 cm / sec. and 6.3 g water / g fiber «

These tests show in comparison with the untreated. Fibers the surprising ability of the fibers of the invention to Creation and maintenance of volume in fiber structures, in wet and dry conditions. Furthermore, the increased ability to absorb and retain water will demons t ries.

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Following the procedure of Example II are impregnated fibers suitable and advantageous for use in diaper pads, Towels and other towels. The products made from hardwood fibers by the method of Example II are excellent Mushroom properties and are particularly suitable for the production of packaging materials and furniture cushions.

Example III

Pipes impregnated internally with wet strength resin are produced by first slurrying undried kraft fibers from bleached softwood from the south with a paser concentration of $ 0.7 in water. Then $ 25, based on the paser weight in the slurry, of the resin "Gasco PR 335: ^w (urea / maldehyde wet strength resin, manufactured by Borden Chemical Co., Columbus, Ohio) in the form of an aqueous solution that is 5 Contains% by weight of the resin, added · The mixture is stirred for a further 15 minutes, the pH value during this time and the subsequent immersion time of 45 minutes being 7. The pH value is then increased to 4.2 by adding 10% sulfuric acid solution At the low pH, the fiber slurry is mixed thoroughly and immersed again for 30 minutes. The impregnated fibers are then deposited on the sieve of a vacuum drum washer and washed in countercurrent with 100 kg water / kg fiber weight. The washed fibers are then formed into a web molded and dried and cured in a drying cabinet for 16 hours at 116 ° C., the fiber product according to the invention being obtained in web form.

After drying and hardening, part of the impregnated pasers is placed in a TAPPI disintegrator at a paser concentration of 0.1 $ slurried in the Yiasser and then closed by hand scooped a web with a basis weight of 3 g / 103 cm. This web is wet under a load of 0.07 kg / cm.

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pressed and dried ^{at 116 ° C.} The dried web has a dry density of 0.035 g / cm under the 0 load and a dry density of 0.070 g / cm under the 0.07 kg / cm load. The dry density of the same fibers without resin impregnation is determined to be 0.142 g / cm with a load of 0 and Ο, ^ βί g / cm with a load of 0.07 kg / cm «,

The wet compressibility, expressed as the apparent wet density, of the impregnated fibers is 0.058 g / cm ⁵ under the 0 load and 0.112 g / cirr under the 0.07 kg / cm load. The wet compressibilities of the resin-free fibers under the same conditions are 0.081 g / cm under the 0 load and 0.168 g / cm under the 0.07 kg / cm load. The wick speed of the impregnated fibers is 0.86 cm / sec., That of the resin-free Fibers 0.58 em / sec.

In comparison with the untreated fibers, these tests show the surprising ability of the fibers according to the invention, inside fibers impregnated with wet strength resin to produce and • Maintaining volume in fibers. . under wet and dry conditions. The increase in the absorption power is also demonstrated.

The invention has been described above using the example of cellulose fibers and wet strength resins of various classes However, other fibers capable of resin deposition inside can also be treated in an analogous manner. The invention Fibers can be used alone or in a mixture for the production of cushions, mats, tiles, sheets and others Fiber structures with the physical properties appropriate to the use.

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Claims (1)

Claims 1. Method of making inside with wet strength resin impregnated cellulose fibers, characterized in that one (1) the cellulosic fibers dispersed in the appropriate concentration to form a fiber slurry slurried in water, (2) Slurry the ρΗ-ϊ / ert of the bevel on a swelling of the bevel promotional value increased, (3) adding the wet strength resin with stirring and dipping at the higher pH mentioned, (4) the pH of the jasers slurry on the fiber contraction and polymerisation of the wet strength resin zes effecting value lowers, (5) separates the cellulosic fibers and washes their outer surfaces free of wet strength resin solids and (6) dry the washed fibers and the wet strength resin hardens inside. 2c, method according to claim 1, characterized in that one wood fibers are used as cellulose fibers. 3 · The method according to claim 1, characterized in that cotton fibers are used as cellulose fibers. 4. The method according to claim 1, characterized in that the wet strength resin solids in an amount of about 5 to about 50? B based on the weight of fiber in the slurry, clogs. 5. The method according to claim 1, characterized in that urea / formaldehyde resin is used as the wet strength resin. 609837/0934 6 «Method according to claim 1, characterized in that melamine / formaldehyde resin is used as the wet strength resin, 7 · The method according to claim 1, characterized in that as a wet strength resin, polyamide / polyamine-epichlorohydrin resin used. 8. The method according to claim 1, characterized in that the cellulose fibers ^m i * a fiber concentration of about
Slurries 0.3 to about $ 2.5. 9 · The method according to claim 1, characterized in that the total time of addition and action of the wet strength resin at the higher pH is about 45 minutes to about 16 hours. 10 «. Method according to claim 1, characterized in that the Total time of addition and exposure to the wet strength resin at the lower pH is about 15 minutes to about
16 hours, 11. The method according to -w-nspruch 1, characterized in that one as a higher pH value 7, as a lower pH value 4.5 and as a wet strength resin, urea / sormaldehyde resin used. 12. The method according to claim 1, characterized in that the higher pH value 5 »is set as the lower pH value 3» 2 and melamine / formaldehyde resin is used as the wet strength resin
used. 13 «The method according to claim 1, characterized in that one Set the higher pH value to 10 and the lower pH value to 7 and, as the wet strength resin, polyamide / polyamine-chlorohydrin resin used. 609837/0934 14 · Cellulose fibers impregnated inside with anti-hate resin in characteristic cellulose fiber strands, who do not have the ability to bind hydrogen. at least 6O5S are insoluble in cupric ethylenediamine and result in increased wick speed in fibrous structures. 15 · Cellulose fibers according to claim 14 »characterized by one in bulk
Wicking speed from 0.7 to 0.9 cm / aec. formed into fibers. 16. Cellulose fibers according to claim 14, characterized by. a content of urea / formaldehyde resin as the wet strength resin. 17 cellulose fibers according to claim 14, characterized by a content of melamine / formaldehyde resin as wet strength resin. 18. Cellulose fibers according to claim 14 »characterized by a content of polyamide / polyamine spichlorohydrin resin as Wet strength resin. For: The Buckeye Cellulose Corporation Cincinnati. Οϊμο, V.St.A. Dr.H.J.Wolff Attorney at Law 609837/003