FI63080C - FOERFARANDE FOER FRAMSTAELLNING AV ETT LIMMAT PAPPERSARK - Google Patents

Description

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Patent- och ragirtarctyralMn AraMun utligd oeh utLskrWkM put> lk * r% d 31.12.82 (32) (33) (31) Privilege claimed — ftegftrd priority (71) (72) Byron Jenkins, 17 Hardwick Avenue, Kidlington, Oxfordshire,

The present invention relates to the manufacture of paper and to the manufacture of a sheet of paper on a paper machine from a cellulosic pulp, in which an aqueous cellulose fiber containing a mineral filler is continuously fed to a pulp-fibrous paperboard. on the wire at the wet end of the paper machine to form a paper web which proceeds through various processing steps to the so-called dry end of the paper machine from which the paper web product is finally exited.The term "paper web" as used herein means both a normal thickness paper web and a thick sheet of paper.

Chemical additives are usually added to the aqueous pulp at the wet end of the machine and can be divided into two groups, a) those needed to ensure that the product meets the given requirements, i. the chemicals required by the product; and (b) those required for the efficient operation of the wet end of the machine, i.e. the chemicals needed for the process. The chemicals required for the product include, for example, sizing agents, starches, wet and dry strength resins and dyes, 2,63080, while the chemicals required for the process include, for example, bulking agents, antifoams. If the additives added to the aqueous pulp at the wet end of the machine could be limited to the chemicals required by the process, this would significantly reduce or even eliminate the necessary chemical treatment of effluents normally required for waste materials from the manufacturing process to prevent environmental contamination. the absence of performance enhancers from the aqueous wet mass at the wet end would significantly reduce the amounts of anti-slime and anti-foaming agents required, provided that the incoming process water is relatively pure. The chemicals that improve the properties of the product, which are needed to make the paper product meet the given requirements, can then be added in alternative ways. One such option is to add chemicals that enhance the properties of the product to the pericarp as a foam containing the chemicals described below.

Non-absorbent paper is needed for many purposes and therefore adhesives are added to it when making paper. The gluing effect can be obtained either by means of "machine gluing", i.e. by mixing the adhesive into the pulp before feeding it to the wet end of the paper machine or by means of "surface gluing", i.e. by applying an adhesive to the paper web. When the paper contains an adhesive, the absorbency of the paper decreases and it slightly resists the penetration of water. It also helps fibers, fillers, and dyes stay on paper. In fact, the adhesive increases the surface tension between the water and the paper surface, thus reducing the wetting effect of the water on the paper.

When making a paper web in a paper machine, it is common practice to perform various surface treatment procedures on the paper web, which may include applying an adhesive and coating the 3 63080 paper web with various coating agents. In these surface treatment procedures, the adhesive or coating composition usually contains water as a carrier for the substance, with the consequence that further drying of the paper web is required. This is required in addition to the normal drying required to remove the water contained in the pulp fed to the wet end of the paper machine by converting it to paper tissue on a continuously moving wire and in the subsequent steps after forming the web.

In order to reduce the amount of water removed in papermaking, it has been proposed to apply the coating compositions as a foam which is mechanically broken after application to the paper web. When foam is used, wetting of the paper web is significantly avoided and thus the drying required to remove water from the web is reduced. It has also been proposed to feed the pulp to the wet end of the paper machine in the form of foam. However, in both of these proposed processes, a foam is formed with a surfactant (also called a surfactant), such as sodium lauryl sulfate, generally at low concentrations, such as 0.01 to 0.5% by weight. It has been found that the use of a surfactant in the foam reduces the degree of paper sizing and therefore neither of these proposals has achieved commercial success in producing sizing paper using normal concentrations of conventional sizing agents such as resin-alum combinations, alkyl ketene dimers, succinic anhydride is used.

In connection with the method according to the invention, it has now surprisingly been found that the advantages associated with the use of foam in the production of glued paper can be achieved without the associated detrimental effect on paper gluing using foam derived from a certain type of non-surfactant blowing agent. More specifically, the invention is characterized in that the foam is made of a 4,63080 foamable mixture containing a hydrolyzed protein foam that reduces the surface tension of water from a normal -5 -5 to 72 · 10 N / cm to a minimum of 45 · 10 N / cm, wherein the foam does not substantially adversely affect the degree of sizing of the paper. Em. The foam made with a foamer does not substantially affect the adhesion properties of the paper web, in contrast to the foam made with a surfactant, which due to its detergent effect can prevent the adhesive particles from adhering directly to the cellulosic fibers and can even physically remove them from the fibers.

Suitable protein blowing agents for use in the present invention are those prepared from natural, regenerated or synthetic proteins by hydrolysis and neutralization of a natural or artificially prepared protein or proteinaceous extract. The protein may be keratin or albumin, present in, for example, horn or hoof flour, skin and blood. The protein blowing agent is usually commercially available as an aqueous solution containing hydrolyzed protein, which solution is mixed with a gas, usually air, if desired using mechanical aids to obtain a foam. Suitable protein foaming agents are commercially available as fire-fighting compositions suitable for fire-fighting purposes, for example as commercially available compositions sold under the tradenames "Nicerol", "Pyrene Standard", "Pyrene Premix" and "CM foam compound" (see British Pat. ).

According to the present invention, a foam made with a protein blowing agent can be used for various purposes in making paper. For example, "per se" foam can be applied to one side of the paper web and the coating composition is applied simultaneously to the other side of the web to correct warping, i. to prevent the web from curling as a result of applying the coating composition. The foam can also be used as a carrier when applying materials that improve the properties of the product to a paper web or paper web. These materials may include, for example, natural or synthetic thermoplastic materials, polysaccharides and derivatives thereof such as starch, animal and vegetable proteins such as casein and gelatin, inorganic polymeric materials, natural or synthetic waxes and naturally occurring waxes, natural or synthetic pigments, such as and adhesives such as rosin and its derivatives.

Thus, when using foam according to the invention, it is possible to apply product enhancing chemicals to the paper web or web at either the wet end or dry end of the paper machine and thus achieve the aforementioned advantages of removing product enhancing chemicals from aqueous pulp and applying foam to the paper web.

Other advantageous features of the method according to the invention are set out in claims 2-6.

Experiments have been performed to compare the effects of a foam formed with a protein blowing agent and a surfactant, namely sodium lauryl sulfate, on glued paper webs. As a result of these experiments, it has been found that when the water repellency of the web was greatly reduced in the case of the surfactant foam, only a very small change was observed when the protein foam was made from "Nicerol" at a concentration ten times that of the sodium lauryl sulfate foam. At the same time, the normal properties of the paper, for example basis weight, bulk weight, ash content, tear strength, tensile strength and puncture resistance, remained essentially unchanged when using protein foam, while in the case of surfactant foam the puncture strength of the paper decreased significantly.

The proteinaceous foams used in the present invention can be prepared by diluting aqueous solutions of commercially available hydrolyzed protein blowing agents to a concentration of, for example, 0.5 to 5% by weight, preferably 1 to 2% by weight of 6,63080, and then introducing a gas, preferably air, into the diluted solution. If the foam is to include a coating material, this may be added to the dilution water for the blowing agent or may be added to the originally prepared foam.

If the foam is applied as such to the paper web or together with the coating material, in most cases it is necessary to disperse the foam after it is applied to the paper web and this can be done by physical means such as a rotating roller, knife or over the entire width of the fabric. For example, a traction blade, an air knife, a Meyer bar, or a reciprocating brush coater can be used to disperse the foam. However, in some cases, for example when using bubble-coated foam, it is not necessary to mechanically decompose the foam because the water portion of the foam coating is removed by drying. The foam or foamed coating composition can be applied to the paper web using a multi-tube dispenser that can be adjusted to apply an appropriate amount of foam or coating composition to the paper web.

The following examples show how proteinaceous foams can be used to make glued paper in accordance with the present invention. In each of these examples, a foam was prepared using a commercially available, hydrolyzed protein copper solution sold under the tradename "Nicerol" -5 as a blowing agent capable of lowering the surface tension of water to 60 · 10 65 · ΙΟ'5 N / cm.

Example 1 Curl Correction with Foam Only This example illustrates the use of the invention in the dry end of an alkaline papermaking system using ground chalk as a mineral filler.

The pulp raw material was made in a conventional manner from fully bleached chemical pulp and waste paper (made from a similar raw material) so that the raw material contained 34% by weight of hardwood, 36% by weight of softwood and 30% by weight of 7,63080% recovered waste paper. An internal alkaline adhesive, namely the commercially available "Aquapel" product sold by Hercules Power Company Limited in the United Kingdom, was added to the raw material to give a pH of 7.2. In addition, an excipient was used to retain papermaking fibers / fillers in the pulp and to maximize adhesive retention, namely "Natron 88", a cationic retention agent sold by Laing-National in the United Kingdom. Powdered chalk, namely Snowcal 8.SW, sold by Cement Marketing Company Ltd., was added as a filler to the paper raw material formed by the fibers, fed as a 25% by weight aqueous slurry to the addition point at a dilute charge level.

On the other side of the coated rotogravure paper was then prepared in a paper machine in system weakly alkaline, whereby the coating was applied at the size press, bill blade coater device using, manufactured by A.B. Inventing Company of Sweden. A coating composition containing latex for bonding purposes and pigments was added to one side of the paper web so that the quality and properties of the selected paper met the requirements for gravure printing paper. Usually, nothing is added to the other side of the paper web at this stage, nor at any other stage in a machine that produced 3600 kg of paper per hour at a speed of 260 meters per minute with a coating weight of 16 g / m 2.

In this example, foam was applied to the uncoated side of the paper web at the junction of the support roll and the paper at the Bill-blade coating machine. The foam was prepared by adding "Nicerol" concentrate to a water tank to form a 1.5% foamable solution which was then pumped by Mono pump to the Billblade coater at a rate of 10-12 liters per minute where it was mixed by passing air into the flow and the resulting foam passed through a Billblade to the support roller of the device.

63080

The following table shows the results with and without the addition of foam.

1. Without foam 2

Quality: single-sided gravure paper 70 g / m.

Normal curvature results should be:

Test: C-U

Supercalender: flat

Start Center End a) B-U B-U B-U) b) flat flat flat) Machine a) F-C F-C F-C) „. ,. ,

Supercalender b) F-C F-C F-C) 2. With foam 2

Quality: single-sided gravure paper 70 g / m Normal warping results as above.

Start Center End a) C-U A-U C-U) b) C-U B-U B-U) Machine a) D-U D-U D-U) b) B-C A-C B-C) Supercalender

In the above results, "U" means the uncoated side of the paper web and "C" means the coated side. The letters "A" to "F" denote a continuously increasing degree of curvature of the paper web, with "A" denoting a substantially flat web and "F" denoting a fully curved web, i.e. tubular product.

From the above results, it can be concluded that the foam helps to correct the internal curvature caused by coating the other side of the paper.

It should also be noted that the Cobb value was 20 in both cases, i. the degree of adhesion of the paper web was not affected.

9

Example 2 63080 Adding Starch to Foam on the Support Roll Side of a Billblade Coater.

Coated gravure paper on the other side was prepared as shown in Example 1 except that in this example a foam / starch mixture was applied to the uncoated side of the paper web through a support roll and a paper interface at the Billblade coating machine. The foamable mixture was prepared by adding "Nicerol" concentrate to a tank containing 6% by weight of starch (Viscosol 410, manufactured by Starch Products Company in the United Kingdom) and 3 parts by dry weight of rosin 5084 (manufactured by BIP ompany in the United Kingdom) to add 1.5 parts by volume of foaming agent . The foamable mixture was then pumped by a Mono pump to the Billblade coater at a rate of 10-12 liters per minute, where it was agitated by passing air into the flow and the resulting foam / starch mixture was passed through a manifold to the Billblade support roll side.

The results in the following table show the difference between adding the foam / starch mixture and without adding.

Score

Roll 1 without foam / starch application

Substance Undervariation .Ah Moisture Gloss Smoothness Otto I.G.T.

% M / C S / C 'F M B _ JO 6.5 23 5.0 4.8 63 12 12 12 12 470

Cobb Mass Puncture Opacity K&N Brightness Micropurface 22 48 160 89 15 82 9 __160 _86___

Roll 2 without foam / starch application__

Substance Unversion Ash Moisture Gloss Smoothness Otto I.G.T.

___% M / C S / C ___ F _M__B__, 72 6.5 24 5.6 3.7 63 8 9 12 10 470

Cobb Mass Puncture Opacity K&N Brightness Micropurface 24 47 135 88 20 82 6 130 86 10 63080

Note. The difference in results indicates Dension waxing on the treated surface and a change in puncture properties. The dension wax take-up test is the standard in the paper industry for determining surface strength; the use of the method is described in Pin T 459 SU65 or Canadian Wood and Paper Technical Section Standard Dll.

It can be seen that there was only a small decrease in the degree of paper bonding.

Example 3 Addition of a wet strength resin with foam to the support roller side of a Billblade.

Coated gravure paper on one side was prepared as described in Example 1 except that in this example, a foam / Kymene 557 blend (Kymene 557 is a wet strength resin manufactured by Hercules Powdwr Company Limited) was applied to the web at the same location as in Examples 1 and 2.

The foam was prepared by adding "Nicerol" concentrate 1.5% v / v with 5% Kymene 557 solution to a conventional tank and pumped through a Mono pump at a rate of 10-12 liters per minute to the same location as in Examples 1 and 2 by blowing air.

Score

The dry uptake of Kymene 557-N into the web was about 0.5%. The properties of the paper changed only in terms of wet strength properties, i. paper with a normal wet / dry puncture or strength of the order of 5% was now 15%. Cobb remained at 22 before and after the Kymene / foam addition.

Example 4

Effect of high starch foam on the wet end of the machine.

The procedure of Example 1 was followed except that the weight of the web 2 was 70 g / m 2, but it was uncoated, i.e. The Billblade head had been removed and thus no paper stacking was used except that which was possible when using foam application.

11 63080

In a paper machine, the paper obtained during the manufacture of the paper web passed through the presses, in this case both were conventional suction press installations. The experiment in this case was carried out in a second press and was as follows: "Nicerol" foam concentrate was added to 1.5% by volume of a 10% solution of the starch and resin shown in Example 2. This was then pumped through a Mono pump at a rate of 10 liters per minute using air mixing to a distribution pipe system mounted above the inlet slot of the second press, i. so that the fed foam got on the top surface of the paper web.

Results These are given in two cases, i. (a) without foam / starch on paper, the weight of the paper obtained being o 70 g / m without surface treatment, and (b) using foam / starch but no other surface additives.

2 (a) Web weight 70 g / m Puncture 90 kPa

Denison waxing top surface 5 bottom surface 5 2 (b) Web weight 74 g / m Burst 170 kPa

Denison waxing top surface 12 bottom surface 16

No changes were observed in properties other than strength, again Cobb (gluing test) remained unchanged. The above experiment lasted 30 minutes on a machine without cracks in the web. Example 5

Preparation of latex / pigment coated web using foam as a coating carrier.

This example illustrates the preparation on a laboratory scale. Paper with a basis weight of 75 g / m was used in the experiment and the coatings were applied to the Skinner using a laboratory coating machine manufactured by Skinner's Company, Southampton.

12,63080 The foam coating composition was prepared as follows: 1.5% by volume of "Nicerol" foam concentrate was added to the mixing vessel together with the coating composition containing latex (binder), calcium carbonate (chalk) as a pigment and carboxymethylcellulose (c.M.C. This mixture was stirred in a cholesterol with a total solids content of 70%. The foam mixture was measured on a web and applied with the blades of a laboratory coating machine. A comparative test was also performed using a sodium lauryl sulfate type surfactant. The following results were obtained.

(a) with "Nicerol" foam

Substance (final) Ash% Gloss Finish 88 g / m2 30 15 40

Porosity Mass x 8 Opacity Outbreak 5 62 90 200 I.G.T, Cobb number Otto 600 23 11

The webs were supercalendered to obtain the above results on matte coated webs.

(b) With surfactant foam

The results obtained were the same as in (a), but the gluing of the paper was completely removed.

Example 6

Add foam / starch to the plate

The foaming mixture of Example 2 was prepared except that a 10% starch content was used. The prepared starch / foam was applied to both sides of the paperboard web as it passed through two rolls of a gluing press used in a paperboard making machine to make paperboard according to a dry manufacturing process.

It was found that the starch / resin mixture applied to the board in the form of foam remained on the surface of the board, forming a board with normal stiffness but improved bending and evenness values.

Claims (6)

63080 13 A method of making a glued sheet of paper in a paper machine, comprising applying foam to the sheet of paper, characterized in that the foam is made of a foamable mixture containing a hydrolyzed protein foam which reduces the water surface tension from a normal value of 72 · 10 N / cm -5 to a minimum of 45 · 10 N / cm , so that the foam does not substantially adversely affect the degree of sizing of the paper. A method according to claim 1, characterized in that the foam is applied to one side of the paper and a different coating composition is applied to the other side of the paper, which minimizes the curl of the paper. Process according to Claim 1, characterized in that the foam contains a product which improves the properties of the product, which is a natural or synthetic thermoplastic polymer material, a thermoplastic polymer material, a polysaccharide or a derivative thereof, an animal or vegetable protein, an inorganic polymer, a natural wax or a synthetic wax, natural pigment or synthetic pigment and adhesive. Method according to one of the preceding claims, characterized in that the foam contains an adhesive. Method according to one of the preceding claims, characterized in that the frother is one which reduces the surface tension of the water from a normal value of 72 · 10 5 to a minimum of -5 -5 to 45 · 10 -65 · 10 N / cm. Process according to one of the preceding claims, characterized in that the hydrolysed protein is hydrolysed keratin or hydrolysed albumin.