JPS61258095A - Treatment of wet paper by foam - Google Patents

Abstract

Specifically structured foamed compositions of paper treating agents applied to wet paper, such as wet-end paper web produced during high speed paper manufacture, provide uniform treating agent distribution and treated paper having properties comparable to dry-processed paper.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to wet paper (v@tpaper) made during paper manufacturing.
r), especially regarding methods for processing wet paper webs 1
, and more particularly to said method using a foaming composition containing a paper treatment agent.

Paper production using what is known in the art as wet laid papermaking involves the production of nonwoven paper sheets, known as paper webs, from a raw material, i.e., wood pulp, using FIAR water in water of paper fibers. Papermaking using the wet process typically involves forming a pulp slurry consisting of paper fibers of up to fine weight in water, casting the fibers onto a screen such as a wire belt, and Drain the water to create a wet end paper web.

The web can also be squeezed out with water throughout the press section. The wet-end paper web is then dried, with or without pressing, typically using air and/or heat to reduce the moisture content of the paper, typically by 10'wt L1, to form a dry-end paper product. shall be.

Paper processing side tubes containing performance or functional chemicals are applied during the papermaking process. Our paper treatment agents are process performance chemicals that can be added to aid in papermaking, as well as
Alternatively, it can be added to paper as a product performance chemical.

Various procedures have been used to apply paper treatments during papermaking operations, such as squeezing, spraying, swiping, or blading, with limited success.

The ffDc-roll involves contacting the paper web with a composition containing a treating agent, either in liquid or foam form, immediately prior to passing through the rolls. The limitations on the nature of the processing agents that can be applied by the diaphragm result in various limitations in the use of the processing agents. Treatment compositions typically must be low viscosity, low solids compositions because the strong hydraulic forces generated in high-speed squeeze crawls can pull the rolls apart, leading to loss of control over composition coverage and other problems. No. Studies show that the fluid infiltration mechanism governs the amount of pick-up as an intensity gradient from the paper surface to the center of the sheet develops in the absence of tj187. The moisture content of the paper from the dry roll application increases significantly, requiring additional drying steps and loading tubes, which increases cost.
Prevents application from being used for wet end processing.

Paper treatment compositions for spraying onto paper webs have other limitations. Usually only low viscosity liquids can be used in the tube. There are limitations to the uniformity of treatment application. The sensitivity of spray to nozzle design and performance, as well as the inherent limitations of spray geometry and overlap, result in ineffective distribution.

Spraying often provides uneven deposition, especially in the case of wide paper webs typically used in papermaking. Spraying is also sensitive to air currents and uniform deposition can be affected. Some treatment agents cannot be used for environmental reasons due to the danger of spreading into the air.

These and other devices for dispensing liquid compositions, such as utilizing dispensing slots or bars, knife blades, etc., require tedious drying operations. Such liquid application cannot be used with wet-end papers where the paper web cannot carry the weight of the applied liquid. Additionally, doctoring off the excess after absorbing the paper treatment from the liquid method is necessary to ensure uniform absorption in a paper web of uniform moisture content.

Processing wet-end paper during papermaking operations is limited by the inherent weakness of paper webs with high moisture content. Wet paper has a weak structure that makes it difficult to handle if it absorbs a certain amount of water. Therefore, much paper processing is directed towards dry end processing. This twisting process depends on the amount of impregnation, i.e. the addition of water to the paper support (5 ubstrat).
Cannot be applied to wet end processing.

The application of foam treatment compositions to dry end paper webs is described in US Pat. No. 4.15&074 (Wallstan). The use of a foam application zone having openings at or upstream of the surface where the foam contacts the paper web is disclosed to uniformly distribute the treatment agent to the paper web. 6m6
From line 5 to column 7, line 21, filling the form in the application area is unacceptable due to either uneven and uncontrolled deposition, or partial or total loss of deposition. Disclosed is the elimination of obtaining adhesion.

U.S. Patent No. 4081.313 (Lyera T (Wl s)
Foamed compositions have been applied to paper webs by drawing them through the screening face of a paper machine using suction and into a foam t web, as disclosed in US Pat. The disclosed process is designed to apply the foamed composition to the paper web by direct mechanical contact without being touched or compressed.

The process of treating a porous support with a foam treatment composition comprises:
No. 670,528 (Wait@r et al.), filed March 25, 1976, entitled "Method for Treating Fabrics with Foams." KoΩ
The foreign patent corresponding to the application was published as a West German patent application on November 23, 1978, i.e. Publication No. 4722,083.
It was published as a number. The application describes a wide variety of porous supports, including woven or nonwoven materials, paper or veneers, that can be treated with foam treatment compositions. Although the Walter et al. application discloses that the porous support does not need to be dry, certain embodiments and methods of producing woven fabrics that are uniformly processed and typically essentially dry to the touch are disclosed. Primarily directed to and containing.

All specific examples treat textile fabrics as porous supports.

Textile materials have a relatively high degree of breathability, a property of the material that facilitates the separation of air and liquid in the foam stream that contacts the fabric or fabric. In contrast, many paper materials, such as unfinished writing paper, book paper, newsprint, liner paperboard, laminated paperboard, container paperboard, etc., are substantially non-porous) and have relatively low permeability. low. Such paper also has relatively low absorbency and is very slow at absorbing liquids compared to cloth. Relatively low levels of absorption, particularly slow rate liquid absorption, pose significant difficulties in obtaining adequate treatment agent distribution from foam compositions at high paper processing speeds such as those used in commercial papermaking. do.

A foam applicator used in applying a foam treatment composition to a support such as cloth or textile is disclosed in US Patent No. 40245.
No. 26 (Ashmus et al.). Foam compositions used in related treatment processes are described in US Pat. No. 4,099.915 (Walter et al.).

It would be desirable to provide a method for uniformly distributing paper treatments via paper webs during paper manufacturing, including gold under normal wet end conditions. like this.

A suitable method must provide a low pick-up level due to the weak wet paper web. The method should be applicable to a wide range of processing agents, including high solids, high viscosity compositions. The method should allow uniform deposition of the treatment agent regardless of paper web properties such as moisture content. The method must also be applicable to relatively non-porous paper materials and must work effectively in high speed papermaking operations.

The present invention relates to a method for processing wet paper. The method includes the following essential steps: The first step includes (4) producing a liquid treatment composition comprising a gas-containing foam and a liquid vehicle, a paper treatment agent, and a blowing agent, wherein the foam is from about 11L005 to about 0.8L005. .9/Density of 1 and diameter of about a, 05 to about (15 cm) average bubble (bubbl)
Dimensions and approx. The foam has a half-life of ~60 minutes. The second step includes (C) passing the foam through at least one foam applicator nozzle and filling the orifice between the upstream and downstream lips of the nozzle with the foam. The wet paper web, both having a water content of about 5% by weight, is passed through a tube nozzle in the direction from the upstream lip to the downstream lip.

Step 4 comprises (D) applying a controlled amount of Form 1 to the surface of the wet paper web to provide uniform distribution of the paper treatment agent into the wet paper web.The present invention further provides a method for making treated paper. Regarding. The method includes the following essential steps. The first step includes producing a wet paper web containing a water content of at least about 5 weights. The second step includes (B) producing a liquid treatment composition that includes a gas-containing foam and a liquid vehicle, a paper treatment agent, and a blowing agent. The form is approximately 0. lL005 ~ approx. 8 l/
cs' density, an average cell size of about 0.05 to about 0.5 mm in diameter, and about 0.5 mm in diameter. It has a half-life of ~60 minutes. Fifth
The step includes (C) passing foam through at least one foam applicator nozzle to fill an orifice between an upstream lip and a downstream lip of the nozzle. The fourth step includes (D) passing the wet paper web through the nozzle in a direction from the upstream lip to the downstream lip. The fifth step includes applying a controlled amount of foam to the surface of the wet paper web to provide a substantially uniform distribution of the paper treatment agent into the wet paper web. The 6th step is (F)1! drying the wet paper web. The seventh step includes (G) recovering the dry treated paper web.

The present invention provides 11! An improved method tube is provided that allows uniform distribution of paper treatment agents to wet paper. The improved method is applicable to a wide variety of paper treatments, including high solids, high viscosity compositions. The improved method is applicable to the production of substantially non-porous paper webs with low liquid absorption rates) and is effective under typical papermaking operations, including high speed paper processing. The improved method works virtually regardless of variations in wet paper moisture content and provides low pick-up levels effective for treating wet-end papers containing moisture content up to near saturation.

The types of paper materials to be processed by the method of the present invention are:
A web or support, e.g. wet-laid (w@t-
1aId) Concerning things made in paper manufacturing operations.

The method of the invention is particularly applicable to substantially non-porous papers with relatively low permeability. Substantially non-porous papers have a relatively high fiber content. Therefore, non-porous paper has a relatively high density compared to the density of the fibers themselves. Substantially non-porous papers are typically characterized by fiber weight and paper material.
It has a density greater than 30'M% of the fiber density in the paper. For example, natural wood fibers have a density of tss 117'cc, so a nonporous paper of the fibers typically has a density of about (L
It has a density as high as 5 to 11/cc. Examples of paper webs for use in the present invention are non-porous papers such as unfinished writing paper, book paper, newsprint, liner paperboard, stacking paperboard, container paperboard, etc., as well as porous papers such as tissue paper, filtration grade paper, etc. Including paper, etc.

The paper web used in the method of the invention can be made on a wet-laid paper machine according to those procedures well established in the art. A typical procedure usually involves
A pulp slurry consisting of about 11 to about 5 weight ≦ fibers in water is cast onto a moving wire belt or screen to produce a wet-laid nonwoven paper web having a water content typically up to about 90% by weight. The paper web is passed through a multi-stage press with seven perforations and a number of water tubes are squeezed out to produce a paper web with a moisture content of up to about 75% by weight.

The wet paper used in the method of the present invention has a water content of at least about 5% by weight up to the paper web O saturation level. Preferably, the wet paper has a moisture content typical of wet paper webs made in wet laid papermaking operations. The wet paper preferably has a moisture content of from about 5 to about 40 grams per weight, most preferably from about 0.0 to about 30 grams per weight.

Although the method of the present invention was primarily directed to treating in-process wet end paper webs during papermaking operations, the method can also be applied to wet, pre-dried paper having an O water content of at least about 5% by weight. equally applicable.

The liquid treatment composition used in the method of the invention includes a paper treatment agent, a liquid vehicle, and typically a blowing agent. A paper treatment agent is an active material that is distributed to a paper web by the method of the present invention. A liquid vehicle is typically required as a carrier to help attach the paper treatment to the paper web.

The paper treatment agent can be present in any form in the liquid vehicle, e.g.
It can be provided by emulsification, solvation or other means known in the art.

The paper treatment agents used in the method of the present invention belong to the class of materials that those skilled in the art will recognize to have beneficial effects when applied to a paper support. Typical paper treatments include functional and performance chemical additives for paper, such as product performance and performance chemicals. Examples of paper treatment agents include sizing aids such as starch, casein, synthetic resins including polyvinyl alcohol,
animal glue 1 and pulp) (pulp@d) Similar materials that can be applied to slurries or formed paper sheets; binders including wet strength and dry strength resins, such as acrylamide, acritetranitrile, polyamide,
Substances such as polyamines, polyesters, styrene, ethylene, acrylic acid, polymers and copolymers of acrylic esters, tetradine, modified rubber, glyoxal; directly
Colorants or organic coloring types commonly used to color paper, including dyes and pigments, such as the class of reactive and fluorescent dyes, pigments such as titanium bicarbonate or similar whitening agents; oil or water repellents; Defoaming agent to the extent that it does not render the blowing agent tube ineffective;
Filler: Surimiside: Latex; Impregnation agent: Includes wax emulsion, etc. Blends of more than one type of paper treatment agent can be used.

Preferred paper treatment agents include sizing aids such as starch, wet paper strength enhancing or dry paper strength enhancing resins such as polyamides, phenols, acrylic resins, crosslinking agents such as melamine formaldehyde resins, and colorants.

The concentration of paper treatment agent is not critical, as long as it provides the paper web with an effective amount to provide a treated paper with the desired properties based on well-established and well-established practices in the art. The particular desired concentration of paper treatment agent will depend on the particular type of paper treatment agent, the speed of foam application, the speed of the moving paper, the paper quality, and similar circumstances that determine the desired amount of paper treatment agent on the treated paper. . Usually about 0. ~70, preferably about 2 to about 50, most preferably about 4 to about 5 oaj1%
of the paper treatment agent is provided in the liquid treatment composition.

The specific type of liquid vehicle is non-negotiable insofar as it serves the function of assisting in the deposition of paper treatment agents onto the paper web. Examples of liquid vehicles include water and the like.

Water is the preferred liquid vehicle.

The liquid composition used in the method of the invention typically contains an effective amount of blowing agent to provide a foam with the required structure. There are some cases in which a paper treatment may have sufficient foaming properties to impart the necessary foam structure. In such cases, the paper treatment agent may also be a blowing agent, so the presence of an added blowing agent is not essential. The particular type of blowing agent is not critical and may be selected from a class of blowing agents recognized by those skilled in the art as capable of forming the required foam. Typically, the blowing agent is a surfactant, or surfactant, which acts to impart the necessary foam properties. Examples of blowing agents include (1) nonionic or anionic surfactants, such as long-chain alcohols or ethylene oxide adducts of long-chain alkylphenols, such as from about 0.0 to 50, preferably from about 0.2 to 20 C1l-Cts 111A secondary alcohol containing ethyleneoxy units of from about 0.0 to about 50, preferably about 0.2
C1·-01- containing ~20 ethyleneoxy units
a linear primary alcohol containing from about 0.0 to about 50, preferably from about 0.2 to about 20 ethyleneoxy units, cs
-ctz.

Alkylphenols; fatty alkanolamines, e.g.
ttf coconut fat monoethanolamine; sulfosuccinate ester salts, such as disodium N-octadecyl sulfosuccinate, tetrasodium N-('
or ( D) cationic or amphoteric surfactant,
For example, distearylpyridium chloride:
) or N-lauryl derivative) or its sodium salt; stearyldimethylpenzyl ammonium salt; quaternized with benzenesulfone and containing nine betaine or quaternary alkyl amines. Such blowing agents are well known and any similar surfactants can be used in addition to those mentioned above. Blends of more than one blowing agent can be used. When choosing a blowing agent for a particular foam, care must be taken to use a blowing agent that will not react excessively with other agents present and that will not disturb the blowing or processing process. Blowing agents include those described in co-pending U.S. patent application Ser. The application is incorporated herein by reference.

The concentration of blowing agent in the composition is non-adjacent and can be any amount sufficient to provide the required foam structure. The amount of blowing agent will vary depending on the particular blowing agent, the particular paper treatment, the foam structure, the speed of foam application, the speed of the moving paper, and similar reasons that vary within the application. The amount of blowing agent typically ranges from about 1 to about 5, preferably from about 5 to about 3, of the liquid treatment composition, and most preferably about 0.0
~about 2.0 wt.

Additional adjuvants can optionally be provided to the fluid treatment composition according to established practices in the art. Such adjuvants include wetting agents, heat-sensitizing agents; curing agents; dispersants; stabilizers; blocking agents; anti-fouling agents; foam stabilizers, #L, hydroxyethyl cellulose or hydrolyzed guar gum, etc. It is included to the extent that it does not unduly affect the desired foam properties during application. The concentration of adjuvant that may be applied follows established practice in the art.

The foam used in the method of the invention contains gas and liquid treatment compositions. Gas is required as the vapor component of the foam. The gas can be any gaseous substance capable of forming a foam with the liquid vehicle containing the paper treatment agent. Typical gaseous substances include air, nitrogen, oxygen, inert gases, and the like. Air is the preferred gas. The relative proportions of liquid treatment composition to gas are effective to provide the necessary uniform foam structure tube and are not critical.

The relative proportions of liquid treatment composition to gas are determined to provide a foam with the required structure in terms of density, cell size, and half-life to provide fast-break properties, fast-break properties, and fast-break properties. The amount is sufficient to provide the form stability of . The density of the foam is approximately 0.0
5 to about 0. G5 to about IIL6, preferably 0.05 to about 0.1 to about (L4j/am). The foam has a diameter of about 0.05 to about (L5, preferably about 0.08
to have an average cell size of about α45−. The half-life of the form is approximately 0. to about 60 minutes, preferably about 5 to about 40 minutes.

Foam density and foam half-life are determined by placing a specific volume of foam into a laboratory measuring cylinder of known weight, such as a 1100 cc or 1 o ace cylinder, determining the weight of the foam in the cylinder, and determining the known volume of foam in the cylinder. and calculate the density from the weight. From the measured density and volume, and the known density of the precursor liquid, it is possible to calculate a liquid volume equal to half the total weight of the foam in the cylinder. The half-life of the foam is the amount of time this volume collects at the bottom of the cylinder.

The foam cell size is the number of cells in the foam sample.
The average bubble diameter size can be determined by t-counting and measuring the diameter of the bubbles and from the measurements.

Foams that can be used in the methods of the present invention include those described in US Pat. No. 4,099,915 (Walter et al.), which is incorporated herein by reference.

The particular order of addition of the components in the treatment composition is not critical; the liquid vehicle, paper treatment agent, blowing agent, and any other additives may be added in any desired manner according to practice in the art. Can be achieved by mixing in order.

Foams are produced using commercially available foaming equipment, usually consisting of a mechanical stirrer capable of mixing metered amounts of gas and liquid treatment composition. The foaming process is controlled by adjusting the volume of gas introduced into the foaming device and the rotational speed of the rotor of the foaming device. The speed of rotation is significant to provide a foam with the required cell size and half-life. The relative feed rates of the liquid composition and gas determine the density of the foam.

The foam is made in one roll and then passed through the foam applicator. The foam fills the orifice between the upstream and downstream lips of the foam applicator before contacting the paper web. The edges of the upstream and downstream foam applicator lips that contact the paper web can be of any chosen shape, such as pointed, tapered, flat, beveled, arched, or other shapes. .

Foam applicators typically form across the entire width of the paper web! -Have sufficient width on both sides to allow coating. During operation, a positive pressure greater than ambient pressure develops in the foam applicator's applicage opening chamber. This pressure depends on several factors including foam density, foam passage rate, paper web passage rate, and absorbency and porosity of the paper web.

Maintain pressure within the foam applicator to allow sufficient foam pressure against the paper web. This positive pressure
That is, a pressure greater than zep is usually about a01 to about 0
．． 0 psl (approximately α0007 to α7Q/scratch, preferably approximately 0.1 to approximately 5 psl (approximately 0.1007 to approximately α2
Kp/a, most preferably from about CLS to about 0. ps
l (approximately 0.02 = 0.05 to approximately 0.7 Kp/aa).

The lip of the foam applicator i is sealed to form a closed system to prevent loss of foam due to positive pressure in the applicator cage chamber inside the foam applicator. The seal between the lips of the foam applicator can be fixed or movable to accommodate changes in paper width.

Preferred foam applicators that can be used in the present invention are U.S. Pat. No. 4,024,524 (Aciems et al.) and co-filed U.S. patent application Ser. A (Cunnlng-ham)
et al.), both of which are incorporated herein by reference. *a The paper web passes through the lip of the foam applicator from the upstream lip to the downstream lip. The fast-bursting, fast-wetting properties of the foam provide instant rupturing of the ingredients and the liquid composition upon contact with the paper web. Absorbs quickly into the wet paper web to provide uniform distribution and penetration. ``The speed at which the paper web passes through the foam applicator can vary over a wide range, including those in typical papermaking and finishing operations.

Typically, the paper web will have a molecular weight of at least about 200, - preferably from about 400 to about 6000, most preferably about 50
Feed at a rate of 0 to about 3500 feet/minute.

The temperature applied (to produce the foam in accordance with the method of the invention) is not critical and may be up to 100°C or higher if the paper treatment agent is heated before and/or during application to the paper web. It is within the range of .

Single or multiple foam application steps can be provided by the method of the present invention. Foam can be applied to one or both sides of the paper web. In multi-sided or two-sided applications, the foam applicator can be supplied with one or more foam treatment compositions produced by one or more foam generating means. The amount and composition of foam applied in multi-sided or two-sided applications can be the same or different in the various applications. The multiple foam application steps may be in direct succession or may be separated by other pressing steps, as may be used in typical papermaking operations.

The support passing through the foam applicator can be assisted by suitable guide means to create the necessary contact along the applicator lip.

The guide means can be placed upstream, downstream or both of the 7-onim applicator. Typical guide means include paper rolls, nips, bars or similar devices effective to help bring the support into contact with the lip across the width of the support. A suitable guide means is the vacuum powder retention means described in co-pending US Pat. The same US patent application is incorporated herein by reference.

The treated wet paper web is dried using established drying procedures in papermaking operations. The moisture content of the dry paper tube is usually reduced to 10% by weight (as low as 0, most preferably from about 0 to about 5% by weight).

The dried treated paper can then be recovered using established procedures in paper manufacturing operations.

, the method of the invention is preferably applied to continuous paper processing operations typical of papermaking and processing operations.

In a typical embodiment, the as-produced wet paper web during a wet-laid papermaking operation is conveyed through a foam applicator. In commercially available foaming equipment, a measured amount of a liquid treatment composition containing a paper treatment agent, a blowing agent, and a liquid vehicle is foamed with a measured amount of gas to produce a foam having the required foam properties. Foam is passed through the foam applicator to fill the orifice between the upstream and downstream lips of the applicator and contact the paper web to provide uniform distribution of the liquid treatment composition onto the paper web. The treated paper web is then dried using a commercial dryer and paper pail and recovered.

Treated paper webs made in accordance with the present invention have a substantially uniform distribution of paper treatment agents while obtaining desired processing properties, such as dry and wet strength, after each processing process. By using the method of the present invention, substantially non-porous wet paper webs, such as wetlaid paper webs, made during papermaking operations can be effectively processed at high speeds to coat wet paper with a substantial amount of paper treatment agent. It was not expected that it would be possible to give a uniform distribution.

The following examples illustrate some embodiments of the invention and are not intended to limit the scope of the invention.

EXAMPLES In these examples, a paper web is processed under conditions designed to simulate wet-end paper web processing during a papermaking operation. The amount of foam applied to the paper web can be calculated from the values given in the example using the following formula: where Vl is the volumetric flow rate of the foam, expressed in ft; C1 is the volumetric flow rate of the paper; The concentration of solids added to the web,
Expressed in weight: V is the linear velocity of the paper web, expressed in minutes; W is the weight of the paper, expressed in 1 b/lf t''; λ is the paper web, i.e. the nozzle. The lateral width of the orifice, J+, expressed in ft; C1 is the concentration of solids in the foam composition, expressed in weight percent of the pretreated web; ρf is the density of the foam, expressed in lb/ft. ” ((equal to Lof4 wounds/cc)).

Dimensions used in the context of the present invention, unless otherwise specified, include length measured along the direction of paper travel and across the foam applicator lip and width measured across the paper web and along the foam applicator lip. measure,
It is like measuring height in a direction perpendicular to a sheet of paper.

The following general procedure was used in the Examples unless otherwise specified. The liquid treatment composition was prepared by mixing the indicated composition containing a paper treatment agent, a blowing agent, and water in the indicated proportions. This composition was applied with air at the indicated volumetric flow rate and the indicated air supply using a commercial foaming device, model number 4MH Oaks (O
akea) was fed into a mixer to generate foam and the foam was conveyed to a foam applicator.

The foam applicator consisted of an applicator spin chamber and a nozzle having a width approximately equal to the paper OI11M. The foam entered the application chamber through a 1375 inch diameter conduit from the foam generating means. The application chamber has a nozzle approximately 9 inches (D5am) high and 18 inches (46 mm) wide and 1125 inches (A18-s) long (i.e., measured in the direction of paper travel). The nozzles were of similar width and length with a height of about 0.5 inches (183).The nozzles were about
It had a flat lip contacting a 5 inch paper web.

The foam passed from the application chamber and filled the orifice between the upstream and downstream lips to the indicated pressure. A paper web having the indicated moisture content was fed through the nozzles at the indicated paper speed from the upstream lip to the downstream lip. The treated paper web was then collected and dried in a Despitch oven on a 07 frame for 5 minutes at 24177 (114°C). The dried treated paper was then collected, tested and evaluated.

The treated paper webs were tested using the following well-established procedures: Test Usage Procedures Basis Weight, lb/ream TAPPI Test Method T-41
0 cal (cat), Mil TAPPI test method'
l'-411 Dry tensile strength, lb/in TA
PPI Test Method T-404 Flew
TAPPI test method'r-511 Gurley stiffness, 1
4 TAJ'PI Test Method T-Test Method Main Erlen, Ib/i ml” TAPPI Test Method T
-403 Resin content, weight % TAPPI test method T-495 Elongation, % 'I'A
PPI Test Method 'r-457 Wet Tensile Strength, lb/1 n
The indications used in TAPPI test method T-456 example are 8 indications with the following meanings:
Description CD Lateral blowing agent I Mixed Cu-1slA secondary alcohol.

9 moles of ethylene oxide adduct blowing agent ■ 7 moles of ethylene oxide adduct blowing agent of mixed C11-1578 type alcohol Foaming agent for ethylene oxide adduct of alcohol ■ Sodium lauryl sulfate foaming mv Dodecylbenzenesulfonic acid MD
Longitudinal Tracer Summer by Bandos Colors and Chemicals Company Product Name Graphol [F
] - green pigment tracer I distributed by ? Product name: Ma by Kai Geigy Co., Ltd.
zllon@R@d A red dye distributed by GRL Dye.

Trainer-I by Sandoz Colors and Chemical Co. Product name: L@tIcophor” Fluorescent dye treatment agent distributed by AC! Polyamide wet paper strength agent treatment ■ Product name by Union Carbide Co., Ltd. BK
A phenolic resin dispersion water treatment agent containing 45ml of 1% wood used as a binder distributed in UA2370.A paper crosslinking agent and binder distributed by American Cyanamid Company under the trade name cym@psys. Acrylic latex foaming agent containing 45% 0 resin used as a binder distributed by Union Carbide under the trade name UCAR@879 Latex V Ni, E, Starley (Man,
n, 5 tartey)! Cultivated starch WP, U distributed by Nu7Acturing Co. in the product range 8tarycβM each. Pick-up amount defined as percent by weight based on the total dry paper weight of the composition added to the paper web.

Example 1 and Control Person-F In these examples, approximately 4.52 oz/yd”, i.e.
Wet-laid paper sheets of wood fibers containing a density of approximately 901 b/h were tested using the Hand M described above. The liquid composition used was as follows: Treatment Agent 1
--3125' 2@85b Foaming agent 1
- (L5 (L5 a5 tracer 1-a2-- water, -99,568,2579,17a
2.5% by weight of activator b 17% by weight of activator In Example 1, the dry paper was first pre-sprayed with water (pr.-
wt.r) to a moisture content of approximately 37.5% by weight, i.e., 60 wt. The pre-wet paper web was then treated with the indicated composition. In Control Examples B-F, dry paper multi-nib tubes were processed under various conditions. The process conditions for these examples are as described in the table below: The treated paper webs, as well as untreated paper webs designated as control examples, were tested using the procedures described above. The results are listed in Table B above. Although the absolute values vary within the particular treatment agent, the results obtained by the method of the present invention for treating paper provide drying and Indicates that treated paper properties such as wet tensile strength are imparted.

Table B Example 1, A-F Paper Analysis Dry Tensile Dry Tensile Untreated 0 0 2B, 215
．． 5 14 118B Surfactant only (L3
0 216116 13 r: WPU of L6CSO% (L3 114 299172 8.4
5.1 Each side D 20%0WPU (1211751518,
48,640 each side E 60% (DWPU rL2 (L94
27:9146 lb5 S, B one side F 40%0WPU (L2 124 17
17.1 45 4.5 One side I 60%0WPU (15105:1714.9
ao 4.4 One side pre-wet: 40% WPU Treatment Example 2 Same as above except that in this example two nozzles were installed, one on each side of the paper tube, to evenly divide the foaming composition into each nozzle. The binder was applied to the wood fiber wet-laid paper sheets using the procedure described below.

The paper was pre-wetted to a moisture content of 30% using a blowing agent (15% by weight liquid composition) giving a foam density of 0.05 to about 0.80 p/cc. Ingredients containing gold: Treatment agent IV a as a blowing agent I (L25 tracer 1 (L175 water)
The process conditions using HL957 were as follows: liquid feed rate C11 min)
″ 90 Air supply amount (7 layers) 16 Paper speed (ft 7 minutes) 50 Paper weight xb/ft”) ao
z6 paper width (rt) α6
25 Total solid content (jiffi%) 40 Impregnated amount (weight s) 40 Solid content impregnated amount (weight %) 16 Foam density (II/cc) 0.0
5 to about 0.55 foam pressure (psl)
(Ll 1 , αIf”a, respectively, upper and lower nozzles Example 3 In this example, a composition of seven combinations of binder and crosslinking agent was prepared using the same procedure as described in Example 2).
applied to a wet-laid paper web. (LO
The paper was pre-wetted to a water content of 30% using a liquid composition of % by weight of the blowing agent Has giving a foam density of 877/CC. The treatment composition contained the following ingredients: 1-1 treatment agent 1 4.4'4 water
54258 Foaming agent■
α5 The process conditions used were as follows: Liquid feed rate (17 minutes) 143 Air feed rate ()7
min) 17, paper speed (ft7 min) 30 ・Paper 0 weight lb/ft")
α02 paper width (ft) c
L65 total solid content (weight%) 27
．． 795 Impregnated amount (wt%) 80a Solid content impregnated amount (!11 weight) 22.2
36 foam density (Il/cc)
0.05 to about 0.84 foam pressure (psl)
l1zs, a, 5zsba half b on each side upper and lower nozzle 4 respectively and control G, H In this example, a combination tube of binder and crosslinking agent, applied to a wet paper sheet of wood fibers using the previously described hand mt did. The liquid composition used was Nidoracer α2 1.
2 treatment agent PI 72.666
4B, 45 treatment agent 1 9.4
6.03 Processing agent 1 1766
1178 Wednesday 1417
44.542 Foaming agent ■ to
t.

a In Example H, the composition of Example G was diluted 6so%.

In Control Examples G and H, each side of the dry paper was treated first. In Example 4, a pre-wetted paper with a moisture content of 17 mm was treated. After drying the treated paper web tube 2007 (93°C) for 3 minutes! Cured at $007 (149°C) for 30 seconds. The process conditions used were as follows.

Example Liquid supply amount (N/min) 9B, 5 147
．． 4 147:4 Air supply amount (j/min)
18 4.5 47 Paper speed (ft7 min) 3o 3o 3゜Paper weight xb/ft”) 0.05 to approx. 0.2
4CLO240,024 paper width (t t )
ts ts ts Total solid content (!%) 37.72 25.04
25.04 Impregnated amount (weight%) 40
60 60 solid content impregnation amount (wt%)
15.1 15.1 15.1 Form density (l/CC) 0.026 LQ5
4 0.05 to about 0.22a for each upper and lower nozzle b The unrecorded processed paper web was tested for 4 minutes using the test procedure described above. The results are listed in Table C above. The results show that essentially equivalent paper properties are obtained when applying the stain treatment to wet paper according to the method of the present invention compared to dry paper treatment.

Example 1 Post-processing heating Dried Dried CD
: 12.5 1135 millennium (psi
) 4α7 34.4 Rigidity (trn-
cs+) MD: 2650 2758CD
: 1428 1454 Porosity (CFVftli 7482 B1
58 tsubo weight (1b/speed) 82.01
axoaa After Boiling C and Control G-H Paper Analysis Cured Cured Dry Cured 22
．． 1 19.9 25.51155
14.8 12.5 1tS49
&9 5 5.4 26 5.553.7
42.7 59.4 45.479
．． 90 75.70 79.50 77.
5084.19 8 (L89 8α56
8173 Example 5 and Controls I-J In these examples, a combination of binder and crosslinking agent was applied to the filter paper. The liquid composition used was as follows: Treatment agent fq 55.55 79
．． 56 Treatment agent 1 010 15.
875 treatment agent 1 tlo 1
086 tracer 1 alo
120 blowing agent 1 (L50
150 water 32.15
For comparison, a dry paper web was treated with Control Example J, whereas Example 5 was treated with (LO4J'/
A55% by weight of blowing agent ■ giving the foam density of CC
The composition was used to prewet the filter paper to a moisture content of 17:6% by weight. Purcess conditions were as follows: Control J2-Male-1-Liquid feed rate (g/min) 149
104 air supply amount (77 minutes) 5.4 1
0 paper speed (ft7min) 1s
1s paper weight Ib/ft”)
a, 024 (l024 paper@(ft)
15 15 Total solid content (Jfiffi%) 3α6
4th step 9 impregnated amount (weight%) 6a
42 Solid content impregnation amount (weight%) 1
8.4 18.5 Foam density (I/C
C) α[+44 [LO3
5 foam pressure (pml l111, α
18 Hatake (111, rL18' former (pm
ig) Treated papers as well as untreated paper tubes designated as Control ■ were tested using the procedure described above. The results are listed in the table below: Table Example 5 and Control I-J Paper Analysis Test Control I Control J Example 5 Resin Ya 0 149
14.5 cal (mil) 19
．． 2 210 2α7 dry tensile strength 1 b
/1n) 4.2 24.7 22
．． 1 Dry tensile strength (lb/In) to
118 j 16 Gurley stiffness (g-a
m) 493 3276 2s1゜Strong 5.2 1000+
1000+ Mielen (pal)
5.4 42.5 56.7 Porosity (CF!1
4/ft 914 77.5 7
L4 elongation (%) α9 564.2 elongation a (%) 4. Oy
, 1s,.

a The results after significant boiling indicate the applicability of the paper treatment agent according to the method of the present invention! It is shown to provide comparable product performance compared to dry end paper processing under similar conditions.

In one example, Lj has a water content of 5-2 to 5.7% by weight and weighs 1
7) Internal size of 89.6 ji/m” (intestinal 1
A) Vellum paper was pretreated with water and wrapped in plastic for several days to give a wet paper with a water content of 19%.

30% by weight treatment agent vt in water - approx. 30 at approx. 90°C
All starch-treated compositions were prepared by boiling for minutes. After diluting the boiled composition to 20% starch by weight, about 75°C
I kept it. Sufficient blowing agent Vt - composition plus about 0.1
The foaming agent was 2% by weight.

a composition tube containing 25% by weight of added tracer 1t-α;
A foam applicator eye fitted with a liquid metering pump, a metered compressed air supply, a foam distribution chamber and a pressure gauge and a foam applicator nozzle lip and suitably sheathed to allow the foam temperature to be maintained at approximately 66°C. The foaming composition was applied under the following conditions:

Claims (1)

[Claims] 1. (A) A liquid treatment composition comprising a foam containing a gas, a liquid vehicle, a paper treatment agent, and a blowing agent is prepared, and the foam has a density of about 0.005 to 1 cm^3. Approximately 0.8
(B) applying the foam to at least one foam applicator nozzle; (C) passing a wet paper web having a moisture content of at least about 5% by weight through the nozzle from the upstream lip to the downstream lip; (D) applying a controlled amount of said foam to the surface of said paper web to provide uniform distribution of said paper treatment agent to said wet paper web. 2. The method according to claim 1, wherein the paper treatment agent is a sizing aid, a binder, or a coloring agent. 3. The method according to claim 2, wherein the paper treatment agent is starch, wet strength resin, dry strength resin, dye or pigment. 4. The method of claim 1, wherein the wet paper has a moisture content of at least about 5% by weight up to the saturation level of the paper. 5. The method of claim 4, wherein the wet paper has a water content of about 5 to about 40% by weight. 6. The method of claim 1, wherein the gas is air and the liquid vehicle is water. 7. (A) creating a paper web having a water content of at least about 5% by weight; (B) creating a liquid treatment composition comprising a gas-containing foam and a liquid vehicle, a paper treatment agent, and a blowing agent; , the foam has a density of about 0.005 to about 0.8 grams per cm, an average cell size of about 0.05 to about 0.5 millimeters in diameter, and a foam half-life of about 1 to about 60 minutes. (C) passing the foam through at least one foam applicator nozzle and filling the orifice between the upstream and downstream lips of the nozzle with the foam; and (D) passing the wet paper web through the nozzle. passing in a direction from the upstream lip to the downstream lip; (E) applying a controlled amount of the foam to the surface of the paper web to provide uniform distribution of the paper treatment agent to the wet paper web; ) drying the paper web; and (G) recovering the dried treated paper web. 8. The method according to claim 7, wherein the paper treatment agent is a sizing aid, a binder, or a coloring agent. 9. The method according to claim 8, wherein the paper treatment agent is starch, wet strength resin, dry strength resin, dye or pigment. 10. The method of claim 7, wherein the wet paper has a moisture content of at least about 5% by weight to the saturation level of the paper. 11. The method of claim 10, wherein the wet paper has a water content of about 5 to about 40% by weight. 12. The method of claim 7, wherein the gas is air and the liquid vehicle is water.