FI109218B - A bonding compound used for neutral gluing of paper or paperboard and a method of making paper or paperboard - Google Patents

Abstract

The invention relates to a sizing composition usable for the neutral sizing of paper or board, which composition contains a size capable of reacting with cellulose, such as alkyl ketene dimer or alkenyl succinic acid anhydride, and an organic complexing agent. The invention also relates to a process for the manufacture of paper or board.

Description

1 109218 i ί

FIELD OF THE INVENTION The present invention relates to an adhesive composition for use in neutral gluing of paper or board. The present invention relates to an adhesive composition for use in neutral gluing of paper or board. The invention further relates to a process for making paper or board.

At neutral pH, the water-repellent (hydrophobicity) of paper and board is controlled by using an alkyl ketene dimer (AKD) or an alkenyl succinic anhydride (ASA) as a sizing agent. Both molecules are considered to react with the cellulosic fiber. The reaction occurs particularly under alkaline or slightly basic conditions with vigor. In papermaking, AKD and ASA are added to an aqueous slurry of fiber and additives (e.g. fillers, retention agents, anti-foaming agents, pH adjusters), which are designed to extract the solid as efficiently as possible, i.e. retention. The water used for the sludge is generally circulated water and the pure raw water added thereto, whereby the water used for the sludge generally contains, for example, about 200 ppm of the alkaline earth metals: calcium and magnesium ions.

It is generally known that pulps containing calcium carbonate, which is used to increase the brightness of paper, consume more hydrophobic chemicals than • ·. ·: ·. masses without carbonate.

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v. · 'The carboxyl groups present on the surface of the cellulose cause a negative charge on the fibers. The amount of charge depends on the surrounding pH. Under initial conditions: Y: 25, the carboxyl group is protolysed and, consequently, the amount of negative charges: T: increases.

,, In general, the adhesives used for hydrophobising purposes are made so that water ';'; The repellent is emulsified in a cationically charged starch. The starch surrounds the water-insoluble hydrophobizing agent in water to form an evenly dispersed milk dispersion. Because of their importance, the dispersion particles are cationic. They have . '1'. tend to adhere to negatively charged surfaces, such as cellulosic fibers.

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Particularly in hard water, divalent alkaline earth metal ions, such as Ca 2+ ions, although also other polyvalent ions, neutralize the carboxyl groups of cellulose fibers, resulting in a corresponding reduction in the negative charge of the fibers. Since the adhesive particle formulated with cationic starch is thought to attach to the surface of the fiber by means of charges, the presence of surface charges in both the adhesive particle and the fiber is important for retention. The Ca2 + ions neutralize the surface charge, which results in a decrease in the retention of the cure adhesive particles. Similarly, the adhesion of cationic retention agents to the fiber depends on the surface charge of the fiber.

Chelating and sequestering chemicals, which can reduce the amount of free ions in water, can also reduce the amount of Ca 2+ ions on fiber surfaces and create free anionic groups to improve retention. However, if these complexing agents are used directly in, for example, circulating water from a paper machine, their use would be relatively high and would cause problems in other machine operation.

Surprisingly, it has been found that the hydrophobization of paper by AKD- and ASA-based chemicals can be improved by the addition or co-administration of small amounts of metal complexing agents into their formulations. By means of the substances added to the adhesive, the complexation of the cations in the fiber near the adhesive particles is obtained, thereby improving the retention of the adhesive, while at the same time keeping the concentration of complexing agents in the circulation water of the paper machine.

: * Whereas, for example, calcium carbonate is a commonly used filler in the preparation of paper; *, the use of complexing agents to chelate all calcium is not sensible as this would lead to the dissolution of calcium carbonate. What is inventive here is precisely the fact that, among the glue formulations, a very small dosage of • · 25 complexes has surprisingly been found to significantly improve gluing. For the functionality of the invention, it is required that the complexing agent forms sufficiently persistent complexes with the AKD-lii on the papermaking machine. with metal cations which may adversely affect the taste. Essential, · · ·. for the operation of the invention, the appropriate amount of '' 'complexing agents are added to the adhesive formulation.

Thus, according to the invention, there is provided a gluing mixture for neutralizing paper or paperboard, which comprises reactive with cellulose; · 'Sizing agent and organic complexing agent.

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The adhesive is preferably an alkyl ketene dimer (AKD) or an alkenyl succinic anhydride (ASA).

The complexing agents are also referred to as chelating agents.

Suitable complexing agents which may be used in accordance with the invention are 5 a) aminopolycarboxylic acids b) N-bis or tris - [(1,2-dicarboxylethoxy) ethyl] amines and c) phosphonic acids.

The above complexing agents may be in acid form or in salt form. Suitable salts include the alkali metal salts and the ammonium salt. Preferred salts are the sodium and potassium salts.

Preferred group a) complexing agents are aminopolycarboxylic acids of the following general formula I.

A2n - (CH 2) a -N - (CH2) b-N - B

(I) A X Ay wherein 15 A is -CH 2 COOH,. ::. B is -CH 2 COOH or -CH 2 CH 2 OH,. x is 0-6, preferably 0-3, ''. y is 0-6, preferably 0-2, a is 2-10, preferably 2-4, and *; '; * 20b is 2-10, preferably 2-6.

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Particularly preferred compounds of formula I are; . ethylenediaminetetraacetic acid or EDTA (B = A, x = 0, b = 2 and y = 1),. ·: ·. diethylenetriaminepentaacetic acid or DTPA (B = A, x = 1, a = 2, b = 2 and y = 1) and '· nitrilotriacetic acid or NTA (B = A, x = 0 and y = 0).

: * '; Preferred group b) complexing agents are N-bis- or tris - [(1,2-dicarboxyl)

'. ethoxy) ethyl] amines of general formula II

4, 109218

COOH R COOH

I (II)

HOOC ^^^ A ^^ k ^^ COOH

where

| .COOH

i ^]

d / \> ^^ COOH

R is hydrogen, an 'alkyl group having 1 to 30 carbon atoms, a 5 alkyl group having 1 to 30 carbon atoms and an additional 1 to 10 carboxylic acid groups, an alkyl group having 1 to 30 carbon atoms, and also having 1 to 10 carboxylic acid ester groups, (poly) an ethoxylated hydrocarbon group having from 1 to 20 ethoxyl groups, or a carboxylic acid amide group having from 1 to 30 carbon atoms, wherein the NR bond is an amide disido bond.

Particularly preferred complexing agents of formula II are the following compounds of formulas A, B, and C:

C

COOH

HOOCv * 1 I

• · \ | ^ / -COOH l COOH

: /—-"./ 'ή yZ -o -— <\ / • · HOOC-x \. F::: o' · '* ·' R, - n

o HOOC. \ .x, -COOH

, Y. COOH \ _Q.-i ^ \ 0- /

I .COOH HOOC- '' COOH

*. * · HOOC \ f ... u HOOC-x \

COOH

; A = N-bis [(1,2-dicarboxyl-ethoxy) -ethyl] -amine (hereinafter abbreviated. ·! ·. 15 BCEEA) ··. B = N-bis [(1,2-dicarboxyl-ethoxy) -ethyl] -aspartic acid (hereinafter referred to as BCEEAA) C = N-tris [(1,2-dicarboxyl-ethoxy) -ethyl] -amine (hereinafter referred to as TCEEA) 5 109218 These complexing agents A, B and C and their preparation are described in patent application FI-962261. Mixtures of compounds A and B may also be used.

Preferred group c complexing agents are phosphonic acids of general formula III

PO3H2

R 1 -C-R 1 I 3 (III) 5 R-2 wherein

R1 is hydrogen, lower alkyl such as -CH3 or - (CH2) n-CH3, amino group -NH2, hydroxymethyl -CH2OH, lower carboxylic acid group - (CH2) n-COOH, lower alkyl phosphonic acid group - (CH2) n-PO3H2 , or a group of formula ^ (CH 2) n -NH 2

-N = C

10 (CHA-CH3 R2 is hydrogen, hydroxyl-OH, phosphonic acid group -PO3H2, lower carboxylic acid group - (CH2) "- COOH or a group of formula *» * 6 109218 χοη2-ρο3η2

-OF

xch2-PO3H2

/ (CH2) n-COOH -CH

X (CH2) n-COOH

/ CH 2 P03H2

(CH 2) n -N

/ xch2-po3h2

-OF

\ / <: η2-ρο3η2

(CH 2) n -N

xCH2 -P03H2 ch2-po3h2 I / CH2-P03H2

-N- (CH2) "- N

nch2-po3h2 f —ch2-n-ch2-po3h2 / Ch2-po3h2 or

\ X-N

V xch2-po3h2. :. --CH2 -N-CH2-PO3H2 / CH2-PO3H2 xch2-po3h2 'R3 is hydrogen, hydroxyl-OH, amino group -NH2, lower alkyl such as -CH3 or - (CH2) n-CH3, lower carboxylic acid group - (CH2) n-COOH or a group of the formula: · -NH- (CH2) n-PO3H2 -NH-CH2-COOH or i 109218

CB ^ ^ -COOH

-OF

xch2-cooh n is 0-6, preferably 0-3.

In the sizing composition according to the invention, the amount of complexing agent may be from 0.1 to 50% by weight, preferably from 0.1 to 20% by weight, and particularly preferably from 0.2 to 3% by weight, based on the amount of sizing agent.

Preferably, the sizing composition of the invention is in the form of a dispersion, further comprising a dispersion stabilizer.

Stabilizers for AKD dispersions include, for example, starch, cationic starch and other polymers such as polyethyleneimine, polyepamine, polydiethyldi-allyl or dicyandiamide compound, polyacrylamide or acid or salts thereof.

For example, starch or other polymers such as water-soluble cellulose derivatives such as hydroxyethyl or hydroxypropyl, methylhydroxypropyl, ethylhydroxyethylcellulose, carboxymethylcellulose, gelatin, guar gum, xanthan gum may be used to stabilize ASA dispersions.

. . In the sizing composition of the invention, the amount of complexing agent may be from 0.2 to 20% by weight, preferably from 0.2 to 10% by weight, and particularly preferably from 1 to 5% by weight of the stabilizer.

In accordance with the invention there is also provided a process for preparing paper or board. ·. ·. 20 using a cellulose-reactive adhesive, characterized in that the organic complexing agent as defined above is used together with the adhesive *.

The complexing agent may be incorporated in the adhesive or may be dosed at the same position on the paper or board machine as the adhesive.

The invention further relates to the use of a sizing composition as defined above for the neutral sizing of paper or cardboard: ":": tong.

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: When the sizing composition or adhesive formulation according to the invention contains starch, the '... complexing agent binds to the starch layer where it is diluted when diluted and' 7-t-forms a complex with Ca ions. When the complexing ion loosens the fiber, the fiber becomes more anionic and The equilibrium constant of the cellulose fiber with respect to the complexation of Ca 2+ ions is known to be about 3. i On the one hand it indicates that cellulose binds ions from the recirculated water and on the other hand it requires * O 4 that the equilibrium constant of Ca adduct complexing , such as the Constants of the above materials are about 10.

The bonding compound works especially for masses made in hard water and in machines with otherwise poor retention.

It is a common belief that the water repellency of paper produced by AKD bonding develops slowly. Rapid bonding is particularly needed when making base paper 10 for coating. Significant improvement can be achieved with the composition of the invention.

Other chemicals used in papermaking, such as starch or calcium carbonate, or the quality of the pulp, do not affect the functionality of the invention. Also, the order in which chemicals are added to the paper machine or other running parameters of the paper machine does not affect the operation of the invention.

The amount of use of the complexing agent in the adhesive formulation may be 0.1 to 50% by weight of the amount of AKD or ASA and 0.2 to 20% by weight of the total amount of starch or other formulation stabilizing polymer. These compounds can be used as such in their acid form or as their alkali or ammonium salts. If the substance is to be used in any of the marshes, it is not appropriate to use it. the salt cation has no significant effect on the performance of the invention.

Current AKD emulsions are physically stable and useful for several weeks. The concentration of AKD in the products may be 0.5-30% by weight. Generally, various starches which are generally cationized with either the quaternary * "· y are used for the formation of AKD formu- YY, whereby the starch retains the cationic charge also under alkaline conditions: Y: 25 or with primary, secondary or tertiary amines having a charge of pH dependent; The amount of starch may be in the range of 0.1 to 10 times the AKD fraction. A variety of anionic chemicals such as lignosulfonates, and, aliphatic or aromatic sulfonates, nonionic surfactants are generally used to disperse AKD wax, such as Y fatty acid or fatty alcohol ethoxylates or cationic surfactants such as fatty acid amines or imidazolines. Polymers such as polyethyleneimine, polyepamine, poly: dimethyldiallyl or dicyandiamide may also be used to stabilize the AKD dispersion. compounds, polyacrylamide or acid and its salts The amount of stabilizing chemicals is 1-200% by weight of the amount of AKD. The use of polymers can not only improve the stability of the product but also affect the performance of the product in paper or board. The addition of stabilizing chemicals is a known technique commonly used in formulating AKD products.

The ASA is dispersed in a paper or board mill with 5 equipment installed for this purpose. The prepared dispersion is immediately run on a paper or board machine. In order to facilitate the preparation of the ASA dispersion, a surfactant such as dioctylsulfosuccinate, octylphenoxypolyethoxyethanol and polyethyleneoxidinonylphenylphosphate, polyethyleneoxysorbitanium trioleate is generally added to the product.

In general, starch or other polymers such as water-soluble cellulose derivatives, such as hydroxyethyl and hydroxypropyl, methylhydroxypropyl and ethylhydroxyethylcellulose, carboxymethyl, guar gum, xanthan gum, polyvinyl alcohol, etc. The dispersion has a droplet size of typically 0.2 to 3 µm. The complexing agents may be added to ASA-based blends well known in the art.

The adhesive composition of the invention is suitable for use in chemical pulps, mechanical pulps, chemimechanical pulps and mixtures thereof.

The functionality of the compositions of the invention is illustrated by the following pre-20 characters. Percentages are by weight unless otherwise stated.

Example 1 • · " ; The change in fiber surface charge by the action of the complexing agent was investigated as follows.

A mixture of pine and birch sulfate pulp in a 50:50 ratio was slurried in ion exchange water and v · '25 milled to a Schopper number of 20 °. The pulp was filtered and reslurried to a consistency of 1% a) ion exchange water and b) ion exchange water containing 0.1% DTPA as Na salt: Y. The masses were stirred for about 1 hour. The pulps were washed with ion exchange water at pH 7. The fiber. ; : charge was determined with polydiallyldimethylammonium chloride and its withdrawal. with the Nα salt of polyethylene sulfonate on a Miitek apparatus.

: 30 a. Mass charge after washing anionic 3.8 pe / g mass ;; b. Mass charge after DTPA + washing anionic 5.6 pe / g mass 109218

Example 2

The effect of the complexing agent on the charge of the AKD adhesive formulation was studied on a Miitek device. To the AKD dispersion stabilized by cationic starch, 6% of the complexing agent 1 and complexing agent 2, based on the amount of starch 5, was added. The cationicity was titrated with the Na salt of the polyethylene sulfonate at pH 3.5. In this example and in the examples below, Complexer 1 contains BCEEA and BCEEAA in a 2: 3 molar ratio and Complexer 2 is TCEEA.

test charge (peg / g product) charge (peg / g) 10 pH 3.5 pH 8 no complexing agent cationic 3.3 anionic 2.8

Complexer 1 cationic 2.7 anionic 3.3

Complexer 2 cationic 2.2

Example 3 In this example, a pulp of 40% birch pulp, 40% pine pulp and 20% calcium carbonate as filler and 5 kg / t pulp was used. A dispersion of 2% starch was prepared from AKD with 0.6% of the amount of AKD in the content of complexing agents 1 and 2. The dose of AKD used was 1 kg / t, whereby the amount of complexing agent was 6 g / t. 20 pulp sheets of 80 g / m2 were prepared from the pulp according to Scan-C 26:76. From sheets »» * '. Cobb was determined 60 min immediately and matured 10 min at 105 ° C. Cobb 60 I '' values decreased even though total retention on hand sheets is nearly 100%. Cobb values * · «» * represent the water absorption of paper and refer to the amount of water absorbed by the paper "·" in a given time (g / m). The lower the Cobb value, the better the gluing result.

Table 1 Laboratory Examination

t I i f I I I

Normal Bundle - Bundle.s t »'·]' ___form. 1 format 2:; ': Cobb 60 Unripe 34,2 28 27,9:' ': Cobb 60 Matured__27,6__25,3__25,8 11 109218

Example 4

The weight of the test machine was 35% pine and 65% birch pulp. The filler used was calcium carbonate at 23% dry weight. At a test machine speed of 80 m / min, paper weighing 70 g / m 2 was run. The application rate of AKD was 5 1 kg / t. The AKD adhesive contained 1 0.3% of the complexing agent in the amount of AKD. Even if the total retention of each test machine was good, the product containing the complexing agent, so-called. unripened instant Cobb 60 (g / m 2) was clearly lower than in the corresponding product without complexing agent.

Table 2 Test Machine __Normal Bump, Form. 1

Total Retention (%) 95.2 95.0

Cobb 60 (g / m2) does not immediately mature .__ 20.5__16.9_ I 1 * • · f * ·

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• · · •> · • * · »* *

Claims (12)

1. Adhesive composition useful in neutral bonding of paper or cardboard, which composition contains a cellulose-reactive sizing agent, characterized in that the sizing composition further contains an organic complexing agent. Sizing composition according to claim 1, characterized in that the sizing agent is an alkyl chain dimer (AKD) or an alkenyl succinic anhydride (ASA). Sizing composition according to claim 1 or 2, characterized in that the complexing agent is a) an aminopolycarboxylic acid, b) an N-bis or tris - [(1,2-dicarboxyethyl ethoxy) ethyl] amine or c) a phosphonic acid. 4. A bonding composition according to claim 3, characterized by complexing pure in group a) is diethylenetriamine pentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid (NTA) or a site thereof or a mixture thereof,,. and the complexing agent of group b) is N-bis [(1,2-dicarboxyethylethoxy) ethyl] amine (BCEEA), N; bis [(1,2-dicarboxyethylethoxy) ethyl] aspartic acid (BCEEAA) or N-tris [ (1,2-dicarboxylethoxy) ethyl] amine (TCEEA) or a site thereof or a mixture thereof. ....: 5. Bonding composition according to any preceding claim, characterized in that the amount of complexing agent is 0.1-50% by weight, preferably 0.1-20% by weight and a • ;. especially preferred amount is 0.2-3% by weight of the amount of sizing agent. I · · Sizing composition according to any preceding claim, characterized in that it is in the form of a dispersion and contains a further stabilizing agent "": for the dispersion. ...: 7. Bonding composition according to claim 6, characterized in that the stabilizing agent is starch or another polymer. Sizing composition according to claim 6 or 7, characterized in that the amount of complexing agent is 0.2-20% by weight, preferably 0.2-10% by weight and a particularly preferred amount is 1-5% by weight of the amount. stabilizers. 109218 Use of a sizing composition as defined in any one of claims 1-8 for neutralization of paper or paperboard. Process for making paper or paperboard by neutral bonding using a cellulosic reactive sizing agent, characterized in that an organic complexing agent is used together with the sizing agent. Method according to claim 10, characterized in that the complexing agent is included in the sizing agent or dosed at the same place in a paper or cardboard machine as the sizing agent. | j Method according to Claim 10 or 11, characterized in that the bonding 10 uses a bonding composition as defined in any of claims 1-8. j • »* · · ♦ I * * k *