FI67736B - AEMNESKOMPOSITION FOER LIMNING AV PAPPER - Google Patents

Description

* * \ · I '* v _' * '67736

The present invention relates to a new, more efficient combination of substances for gluing paper and its use for the production of glued papers. A particular object of the invention is to adhere hydrophobic sizing agents for sizing paper to pulp fibers in their aqueous suspension by means of a combination of a cationic and anionic adhesive or retention agent.

The sizing agents included in the combination may be previously known sizing agents used in paper sizing, such as resin acids, enhanced resin acids, ketene dimers, caramyl chlorides, succinic anhydrides, fatty acid anhydrides or fatty acid chlorides.

The combination of substances according to the invention provides virtually complete adhesion of the adhesive, i.e. retention to the fibers of the pulp over a much wider pH range of the fiber suspension. In addition, lower amounts of sizing agent can be used compared to hitherto known sizing methods, and there is no need to use retention aids that degrade paper quality, such as alum.

The term 'paper' as used herein means in the form of sheets, webs or molded articles made from fibrous cellulosic materials. They also include similar products made from combinations of cellulose and other fibrous material, where the other fibrous material may be a synthetic material such as polyamide, polyester and polyacrylic fiber, or a mineral fiber such as asbestos and glass. The percentages given are percentages by weight, unless otherwise stated.

\ 2 '. , 6 * 77 3 6. . The purpose of gluing paper is. prevents or slows the penetration of aqueous liquids into the paper and thus makes the paper water repellent, i.e.. hydrophobic. In resin gluing, the resin glue is added to the fiber suspension in a pH range of 4 to 6. Aluminum sulfate, i.e. alum, which forms a complex with the resin acids, is used as the hetentifying agent. The most common application rates are 0.2-0.6> resin by dry weight of the paper, with the required amount of alum being 0.1-0.3. However, alum oxidizes slightly to alumina by the action of oxygen in the air, causing the resin-bonded paper to turn yellow. Resin sizing must be done in an acidic pH range because the resin-alum complex is not stable in the neutral or basic pH range. Therefore, temporal fillers such as calcium carbonate cannot be used in connection with resin sizing either. The use of optical brighteners in the acidic pH range is also out of the question. The strength properties of the paper deteriorate in the acidic pH range, as do the printability properties of the paper. In addition, alum has caused disadvantages due to corrosion in the papermaking process.

Uneus of the disadvantages of resin sizing can be avoided by using synthetic adhesives. As their retention aids, cationic polymers such as cationic starch, polyamide epichlorohydrin or polyaxylates are generally used, and the sizing can be carried out without alum in either the neutral or alkaline pH range. Also temporary fillers can be used. The strength, printability and brightness properties of paper glued in the alkaline pH range are also better than those glued in the acidic pH range.

The most commonly used synthetic adhesive today is a fatty acid derivative based on a ketene dimer. The adhesive, like the resin adhesive, is added as an aqueous dispersion to the pulp stream at a dosage of generally 0.1 to 0.3% of the dry weight of the paper. In connection with the addition of an adhesive, a retention aid is added to the pulp stream, most commonly cationic starch, the dosage of which is usually 0.5 to 2 times the dosage of the adhesive. The disadvantage of ketene dimer sizing is the slow maturation of the sizing * compared to resin sizing. Since gluing does not yet reach its full power on the paper web, it is usually necessary to increase the amount of surface glue to be added with the glue punch, and more heat must be used to dry the paper web than when using resin glue. However, less ketene dimer adhesive is required than resin adhesive to achieve the same final level of sizing. ';. 3 '' 67736. I 's sex, but · on the other hand, ketene dimer glue is considerably, more expensive than resin glue.

In addition to ketene dimer adhesives, other synthetic adhesives have recently been developed which contain various cellulose-reactive groups such as acid chloride, carbamyl chloride, carboxylic acid anhydride or dicarboxylic acid anhydride groups. The best known are succinic anhydride adhesives of the general formula / ° R. - H - C - c '' l '/) r2 c - c 0

Where R 1 and R 2 are either both or only one of them hydrophobic radicals or together form a hydrophobic radical, wherein the succinic anhydride is attached to the backbone of the hydrophobic carbon chain. Said hydrophobic radicals include straight-chain or cyclic saturated or unsaturated hydrocarbons having more than five carbon atoms. R 1 and R 8 may also be saturated or unsaturated fatty acids, their esters or salts.

The reaction of succinic anhydride-based adhesives with cellulose is considerably faster than that of ketene dimers. Generally, they are dispersed in water at the point of use, after which they are added together with the cationic starch or a synthetic cationic polymer to the pulp stream. A good level of sizing is already achieved with the drying cylinders of a paper machine, but the required dosage is 1.5 to 2.5 times the dose of ketene dimers compared to their work.

It has now been found that by using the composition of the present invention for hydrophobic sizing of paper, the dosage of sizing agents can be significantly reduced, their reaction with cellulosic fibers can be accelerated and the use of harmful retention aids such as alum can be avoided. All known fillers can be used with the combination of substances, and their retention, as well as the finest fibrous material in the pulp, is improved. The combination of substances consists of a conventional adhesive and an associated two-component retention system, and can be described by the following scheme: (K +) - adhesive - (A-) '' n 'm.

· 4 677 3 6 • V. 'wherein the polymeric compound' (K +) n means a cationic polymer such as {.

cationic starch, cationic mannogalactan, polyethyleneimines polyamine, polyaininediamine, polyacrylamide and melamine formaldehyde, and (A) m anionic compound such as polysilicates, carboxymethylcellulose and xaxoxylated polyacrylamide.

It is essential that the combination of substances forms an agglomerate, i.e. a molecular aggregation, which adheres to the fiber as effectively as possible. Most preferably, this is achieved so that the total charge of the formed agglomerate remains positive, so that the ratio of cationic to anionic polymer is kept within certain limits. It is most preferred for the invention to keep the ratio of cationic to anionic polymer in the range of n / m in the range 1: 1 to JO: 1, preferably 1 # ?: 1 to 10: 1, with the resulting agglomerate having the most favorable total charge for retention.

The cationic polymer component of the combination of substances of the invention may be derived from a natural polymer or synthetic. The latter are cationic starches, the starch of which may be derived from barley, wheat, potatoes, corn, rice, etc. The starch is made cationic by known methods with the aid of ammonium compounds; most commonly, quaternary ammonium compounds such as 3-chloro-2-hydroxypropyl-trimethylammonium chloride are used. The degree of substitution may be 0.01 to 0.05.

Another natural polymer that can be used to make the cationic subcomponent of the invention is a manno-galactan polymer known as guar gum. Said polymer is obtained from a guar plant cultivated in Southeast Asia and chemically it is a straight chain of mannose units with individual galactose branches. Guar gum can be made cationic in a known manner, as can starches. The degree of substitution can be 0.01 - 0.05 ·

Synthetic polymers used in accordance with the invention include polyacrylamides, polyethyleneimines, polyamines and polyaroidarines. Their cationic groups are amino or amide groups. Melamine-form aldehyde polymers can also be used; they are prepared by polymerizing water-soluble methylol melamine salts. Polyacrylamides have a molecular weight of 6 to 10, and the other synthetic cationic polymers mentioned have a molecular weight of 10 to 3. 10 ^. Synthetic polymers are chemically active in the pH range of 4 to 8. Their preparation is known and they are prepared. '. \, 5. '. 6.77 3 6. I. ''.

... · Practices including Allied Colloids Ltd., BASF AG. and Kemira 'Oy. The longer the polymer chain, the more effective the cationic ‘component’ is.

As the anionic component of the combination of substances according to the invention, colloidal silicic acid can be advantageously used, which can be in various forms, such as polymeric silicic acid or colloidal silica sol. The best results are obtained using a silica sol with a SiO 2 content of 2 to 60 ¢, preferably 4 to 30. The specific surface area of the colloidal silica of the sol should be 200 to 1000 m / g, and the best results are obtained with a specific surface area of 100 to 700 m / g. , wherein the colloidal silica particles have an average size of 1 to 10 nm. The silica sol is stabilized with an alkaline solution so that the molar ratio SiO 2: Me 2 O = 10: 1 to 300: 1, preferably 15 h 1 to 100: 1, where Me can be Na, K, Li or Ng 2. Eligible silicon sols are manufactured by Nalco Chemical Company, Du Pont & de Nemours Corporation and EKA Kemi Ab, among others.

Some other silicon compounds may completely or partially replace the colloidal silicic acid as an anionic component of the compound of the invention.

Such is mainly the clay mineral bentonite, which can also be suspended in water. Bentonite is known in the art above all as an abrasive. Also suitable as the anionic component are water-soluble cellulose derivatives such as carboxymethylcellulose and synthetic polymers such as anionic polyacrylamide made anionic by attaching carboxyl groups.

The retention aid combination, like the adhesive, is added to the pulp suspension prior to paper web formation. Both sub-components of the retention system can be mixed together before being added to the pulp suspension. However, such a procedure does not give an optimal result. It is more preferred to form the combination of substances according to the invention in a pulp suspension so that the retention components are added separately, suitably diluted, to the fiber suspension, which is kept in sufficient agitation. The adhesive may be added either before or after the addition of the retention components, however, synthetic adhesives may be added after the addition of the retention components. Of the retention components, it is preferred to add the anionic component suitably diluted prior to the cation. It is also possible to add both components at the same point in the fiber suspension, however, so that the dosages are made separately. If mineral fillers such as kaolin, talc, calcium oxonate or the like are used, a portion of the cationic retention component is added with the addition of the adhesive. The above applies in particular to cases where the cationic retention component is used as the cationic retention component. colloidal silicic acid as the anionic component If only synthetic polymers are used as retention aids, the cationic retention component is preferably added before the anionic.

When using the combination of substances according to the invention for gluing paper, the pH of the pulp suspension can be 4 to 9. Optimal retention and sizing results are obtained when the pH of the pulp suspension is 6 to 8. Thus, when using a resin sizing, the components can be resin glued in the neutral pH range so far it has been impossible due to the use of alum as a retention aid. In addition, it should be noted that when the retention system of the cationic and anionic components described above is used as part of the combination of substances according to the invention, the retention of the fillers and fines contained in the pulp suspension is also improved.

The invention is further illustrated by the following examples, which illustrate various embodiments of the invention without, however, limiting the scope of the invention: 7 · · .: .... «'67736

Example 1 · · '·>

One part of bleached pine sulphate cellulose and three parts of bleached birch sulphate cellulose were ground at a consistency of 4.0 to a degree of grinding of 21.5 ° SR · To this fiber suspension was added a resin adhesive dispersion until the amount of dry resin based on the amount of fiber was then diluted to 0.30 fo.

0.15% of the dry matter was added to the fiber suspension, based on a colloidal silica sol with a dry matter of 1.50% and a specific surface area of 40 m 2 / dry gram. after a short mixing, 1.00 of a cooked cationic starch dispersion with a dry matter content of 3.20% and containing 0.040 molar parts of quaternary ammonium groups per mole of anhydroglucose was added to the pulp. Finally, an additional 0.15% of the above-mentioned Union component was added to the fiber suspension, after which the pulp suspension was diluted 0.2 in.

Sheets of the pulp suspension were made in a laboratory sheet mold according to Scan C 26:76 and Scan M 5 * 76. The gluing strength of the sheets was determined as the Cobb ^ number according to Scan P 12:64. As a comparative test, a gluing test was performed on the same mass using only resin without retention aids, and a second comparative test in which alum was used as the retention agent of the resin in the usual manner. The results of these experiments in different pH ranges are shown in the following table: pH Resin Adhesive Anionic Cationic Alum J Cobb ^ \ component component (g / m ^) '% of paper dry matter; 5.5 0.30 '- - 157.7 5.5 0.30 - '- 0.30 20.1 1 5.5 0.30 0.30. 1.00 - 20.3; 5.5 0.20 - - 0.30 37.3! 5.5 0.30 0.30 1.00 - 21.2; --------- ------------------------------------- 1 '' - ---—-------------------- f 7.2 0.30 - - 0.30 103.5 1 7.2 0.30 0.30 1.00 - 20 , 6 j

_______________________________________________________ _ ______I

I I i θ, ο 0.30 I - - 0.30! 151.3 j 8.0 0.30! 0.30 I 1.00 - i 21.0 i -------------------------’______________ i_____________i__________i____________; . 8 67,736. . . . .

It appears from the table that the combination of substances according to the invention provides an effective sizing effect over a wide pH range. The results further show that, using the combination of substances according to the invention, the resin can also be used as an adhesive in both the neutral and alkaline pH range.

Example 2

The sizing test according to Example 1 was repeated using the combination of substances according to the invention in different proportions. The results are shown in the following table: 60 pH Shrink Glue Anionic Cationic Cobb Component Component (g / rn ^) ---------------------------- X- -------------- io of paper dry matter 5.5 0.50 0.152 1.00 59.3 5.5 0.50 0.53 1.00 20.1 5.5 0.50 0.50 1.00 51.2 5.5 0.50 1.00 1.00 81.0 __________ \ _______________________________ __________________ ____________ 7.2 0.50 0.152 1.00 72.1 7.2 0.50 0.53 1.00. 20.3 7.2 0.50 0.50 1.00 28.1! 7.2 0.50 1.00 1.00 82.0 |

The results show that the best sizing effect is obtained with a ratio of 1: 5 of the anionic and cationic components. In addition, it is stated that pH has no effect, since the best suction effect is obtained with the same ratio in different pH ranges.

Example 3

The sizing test of Example 1 was repeated using a pulp to which filler had been added for $ 20 of dry fiber. A mixture of $ 50 talc and $ 50 calcium carbonate was used as filler. The filler was dispersed into the $ 30 aqueous dispersion prior to addition to the pulp. In the comparative experiment, resin glue was used in the usual way with alum. The results obtained are shown in the following table: 9 '. 67736 -; :. - ^ -τ —'i.: 601 r 1 pH Resin- Anionic Cationic Aluna Cobb Tensile- Ash glue component component index

Zt 7, 7. . "~ ~ (g / w?) (Nm / g)% <f0 of paper dry matter \ / 0 / / 5.5 0.30 · 0.33 1.00 - 51.2 73.1 16.2 | 5.5 0.30 0.67 2.00 - 37.6 77.6 18.1 | 5.5 0.40 0.33 1.00 - 25.7 75.6 17.0; 5.5 0.40 0.67 2 .00 - 21.3 78.1 18.9; i 7.5 0.40 0.33 1.00 - 24.5 88.4 17.0 | 7.5 0.40 0.67 2.00 - 20.0 91 .0 19.3: 5.5 '0.40 - - 0.40 28.1 85.3 15.8 j 7.5 0.40 - - 0.40 151.2 80.3 14.4: ______________________________________________________________________'

The tensile index was determined according to Scan P 16:76. The results show that, in the manner according to the invention, the resin adhesive can also be used with alkaline fillers. At the same time, it can be stated that since sizing can be performed in the neutral pH range, the strength properties of the obtained paper are better than those of resin-glued paper in the usual manner in the acidic pH range. The results also show that a better sizing effect is obtained by increasing the proportion of the combination of substances in the paper and in particular by increasing the proportion of the anionic and cationic components.

Example 4

The sizing test according to Example 1 was repeated using kaolin (SPS) as the bulk filler for $ 25 of dry fiber. The cationic component of the adhesive combination was a commercial polyacrylamide having a molecular weight of 10. The anionic component was a silica sol with a specific surface area of 600 m / g.

The adhesive of the combination was synthetic dialkylcarbamyl chloride. In the comparative experiment, the same adhesive was used and cationic starch alone was used as the retention agent. The results were as follows: .10 677.36 * · i '6θ pH K & rbamyl- Anionic Vationic' Cobb Tetrachloride Adhesive Component Component Index & Paper Dry Matter (& / m) (lun / g)

——— »- --------- T

6.5 0.15 0.017 0.025 25.1 50.2 and 7.0 0.15 0.017 0.025 24.2 61.1 7.5 0.15 0.017 0.025 27.5 67.2 8.0 0.15 0.017 0.025 25.2 70.1 - ~ - - - ~ · τ - - - - - - - - - - - - - - - - “- - - —— - - - - - - - - - - ~ 8.0 0.15 - 1.00 24, 1 87.1 j (starch) J;

It can be seen from the results that polyacrylamide can also be used as the cationic component of the combination. It is also found that the strength properties of the paper are of the same order of magnitude, although the amount of the 'retention component' of the adhesive combination was significantly lower than that of the cationic starch of the reference combination.

Example 5

The sizing test according to Example 1 was repeated using 1-octadecyl succinic anhydride as the sizing agent, which was dispersed before use as described in EI 57 993. The dispersed adhesive was dosed in the same manner as in Example 1. In the comparative experiments, only cationic starch was used as the adhesive retention agent. The results were as follows: pH Adhesive Anionic Cationic Cobb ^ component component ------— —------------------—-------- --—- / y 2 \ fo of paper dry matter '7.5 0.20 0.017 0.10 V 20.1 7.5 0.20 0.053 0.20 21.4 7.5 0.20 - 0.10 100.1 7.5 0.20 - 0.20 51.3 7.5 0.20 - 0.40 41.0 -----: _________________ L _____________ 1 -------------- f___________________

The combination of substances according to the invention gives a better sizing result than using only the cationic component as a retention aid.

· Τα ·. .,. '67736

Example '6 ·' In this series of experiments, maleinised soybean oil obtained by reacting one mole part of succinic anhydride with one mole part of soybean oil in a known manner was used as an adhesive for the combination of substances. Otherwise, the dispersed adhesive was dosed as in Example 1. In the comparative experiments, only cationic starch was used as the retention agent. The results were as follows: pH Adhesive Anionic Cationic Cobb ^ component component - 0 -------- i -----------] ------------- (g / m2) and from the dry matter of the paper 7.5 0.13 0.017 0.10 21.2 7.5 0.13 0.035 0.20 20.9

- ““ I

7.5 0.13 - 0.10 120.1 7.5 0.13 - 0.20 97.2 7.5 s' 0.13 - 0.30 45.3

Example 7

A full-scale test run was performed on a paper machine using a combination of substances according to the invention for pulp gluing. The current capacity of the machine was 11.3 tons of paper per hour and the driving speed was 430 m / min.

A bleached sulphate pulp with 55 ° birch sulphate, 17 fo pine sulphate and the remaining waste fiber pulp was used in the test run. The filler used was a talc-carbonate blend, which accounted for $ 23 of the finished Paper Product at best. The basis weight of the finished paper product was 100 g / m 2.

A commercially available alkyl ketene dimer was used as the adhesive in the test run. The cationic and anionic components of the material combination were the same as in Example 1 and had an aspect ratio of 1.4 s 0.39 ·

The cationic starch was boiled at 90 ° C for about 30 minutes and diluted to a feed concentration of 0.8 fo. It was fed to a pulp tank with a pulp consistency of 3.0 fo. Filler and half of the anionic silica sol were metered into the same tank. The remainder of the silica sol, together with the adhesive, was metered into the pulp before the headbox.

•. 12 · 67736 • As a reference run, a normal production run was used in which cationic polyacrylamide was used as the adhesive retention agent. In the test run, the amount of adhesive was changed until the Cobb 2 value of the test paper was the same as in the actual run. The results were as follows:

Cobb ^ Cationic Anionic Adhesive o Component Component Amount (β / «) ---------------------------------- ----------------- io of paper dry matter --- j.

28 Poly acrylic - 0.10 j amide i _________________ · _______________________ ___ _ _ _ | 28 Cationic Silicic Acid Sol 0.06 starch j 1.4 i 0.39 1 °

The results show that using the combination of substances according to the invention, the amount of adhesive could be reduced by $ 40 from the amount required to achieve the same level of Cobb 2 with the combination of substances used so far.

s

Claims (5)

A combination of a 3-component adhesive for use in the hydrophobic sizing of paper, which consists of an adhesive and a retention agent combination (K +) n - an adhesive - (A), characterized in that the combination is a complex of an adhesive and a cationic and anionic polymer , wherein the adhesive may be rosin acid, enhanced rosin acid, alkyl ketene dimer, carbamoyl chloride, succinic anhydride, fatty anhydride or chloride, and wherein the cationic polymer is cationic polyamide imine, polyamine or polyamine, cationic guar gum, polyacrylamide, polyacrylamide, polyacetamide and wherein the anionic polymer is colloidal silicic acid, bentonite, carboxymethylcellulose or carboxylated polyacrylamide. 1 3 Claims: 6 77 3 6 A combination of substances according to claim 1, characterized in that the degree of substitution of the cationic starch is 0.01 to 0.05 and that the degree of substitution of the cationic guar gum is 0.01 to 0.03. 3. Amneskomposition enligt patentkravet 2, känne - gtecknad därav, att polyacrylamide molecules 10 to 7 10 and polyethenemines, polyamines and polyamidamines molecules 103 to 3 x 106. 4. 4. Ammeskompositien enligt patentkravet 1, knnne - teck , the ratio is preferably 1 to 1: 30: 1, the ratio is 1.5: 1 to 10: 1. A combination of substances according to claim 2, characterized in that the polyacrylamide has a molecular weight of 10 to 7 10 and the polyethyleneimine, polyamine or polamidamine 3 6 has a molecular weight of 10 to 3 x 10. Composition according to Claim 1, characterized in that the ratio of cationic to anionic polymer of 25 n: m is from 1: 1 to 30: 1, preferably from 1.5: 1 to 10: 1. Combination of substances according to Claim 1, characterized in that the colloidal silicic acid is in the form of a colloidal silica sol having a surface area of silica particles of 200 to 1000 m 2 / g, preferably 300 to 700 m 2 / g. Combination of substances according to Claim 5, characterized in that the silica sol is stabilized with an alkaline solution so that the molar ratio of SiO 2: 2: Me 2 O is from 10: 1 to 300: 1, preferably from 15: 1 to 100: 1, where Me can be Na, K, Li or NH 4 · 67736 Use of a combination of substances according to the preceding claims for hydrophobic sizing of paper, characterized in that the cationic and anionic polymer components of the combination are added separately to a pulp suspension having a pH of 4-9, preferably 6-8, and that the sizing agent is added separately or together with either the cationic or anionic component or part thereof in the pulp suspension. 1. A 3-component composite for hydrophobicization of 10 papers, preferably with a limestone and a retention medium composition (K +) n - limestone - (A) turns into a mixture, which comprises a complex composition with a limestone and a cationic polymer colors limiting the resin, non-activated resin, alkyl ketene dimer, carbamoyl chloride, fatty acid anhydride, fatty acid anhydride or chloride, and flashing cationic polymers such as cationic starch, cationic polyurethane, guar gun, polyethylene polyamide-Amine, and anhydrous anionic polymers with colloidal kieselguhr, bentonite, carboxymethylcellulose or carboxylated polyacrylamide. A composition according to claim 1, which comprises a cationic starch substitution gradient of 0.01 to 0.05 and a cationic guar gum substitution gradient of 0.01 to 0.03. 5. Smneskompositiön enligt patentkravet 1, kän n e e -