FI97405B - Procedure for mass gluing of paper, cardboard and cardboard - Google Patents

Abstract

According to a paper, paperboard and cardboard internal sizing process, resi n size is used, as well as cationic polymers containing polymerized vinylamine units as fixing agents for the resin size.

Description

97405

Pulp gluing method for paper, cardboard and board

Explanation

The invention relates to a pulp-5 gluing process for paper, cardboard and paperboard using resin glue and cationic polymers containing vinylamine units when polymerized.

U.S. Pat. No. 4,421,602 discloses partially hydrolyzed homopolymers of N-vinylformamide containing N-vinylformamide and vinylamine units. They are used as retention, water separation and flocculants in the manufacture of paper.

It is known from EP-A-0 216 387 that copolymers containing 95 to 10 mol% of N-vinylformamide and 5 to 90 mol% of ethylenically unsaturated monomers are added to the pulp as wet and dry strength agents before sheeting. selected from the group consisting of vinyl acetate, vinyl propionate, C 1-4 alkyl vinyl ethers, N-vinylpyrrolidone, esters of acrylic and methacrylic acid, nitriles and amides, in at least partially hydrolysed form, containing up to 100 mol% of formyl groups split from the copolymer, in amounts of 0.1 to 5% by weight, based on the dry fibers.

DE-OS 3 203 189 discloses sizing agents based on adhesion and gluing accelerators based on hydrophobic, cellulose-reactive sizing agents and polymers which contain primary, secondary or tertiary amino- and / or quaternary ammonium groups which are directly bound. or via side chains. These cationic polymers also include hydrolyzed polymers of N-vinylformamide and partially hydrolyzed copolymers based on N-vinylacetamide and vinyl acetate. According to DE-OS, hydrophobic, cellulose-reactive sizing agents are preferably alkyl ketene dimers, anhydrides, such as colophonium anhydride, and isocyanates.

The best-known pulp-5 seasoning based on natural products is resin glue. These are compounds which are not reactive with the cellulosic fibers and which are blended by adding binders to the cellulosic fibers in the pulp. Suitable fasteners are, for example, aluminum sulphate and, according to DE-AS 1 070 916 and EP-PS O 187 666, cationic dicyandiamide resins. When there is room for improvement in cationic dicyandiamide resins, aluminum sulfate and alum have the disadvantage that in their presence it is not possible to work with calcium carbonate as filler 15 and that the resulting papers are not sufficiently aging resistant due to working in an acidic pH range.

It is an object of the present invention to provide a method for performing pulp sizing of paper, cardboard and board, wherein the sizing can be performed in a neutral pH range and in which aging-resistant papers are obtained.

According to the invention, the task is solved by means of a pulp gluing method for paper, cardboard and cardboard; 25 resin adhesive and an adhesive for attaching the resin adhesive to the cellulosic fibers using cationic polymers containing vinylamine units copolymerized as the adhesive.

In the present context, resin adhesive is generally understood to mean products used for pulp sizing of paper which are based on natural substances and which are, for example, resin adhesives based on hydrogenated rosin, pine resin adhesives, reinforced resin adhesives, dry resin adhesives or emulsions rich in free resin. These 35 products are non-reactive resin adhesives which, when used alone in the pulp, do not glue the paper but must always be used in conjunction with an adhesive. Suitable resin adhesives are disclosed, for example, in "Papier", Volume 43 (5), 188-192 (1989). As in the known pulp sizing methods, the present process also uses resin sizing in an amount of about 1 to 4, preferably 1.5 to 3% by weight, based on the dry pulp in each case.

According to the invention, the pulp sizing of the paper is carried out, in the presence of small amounts of aluminum sulphate and / or alum, using cationic polymers containing vinylamine units copolymerized. Aluminum sulphate and alum are used in amounts of less than 5% by weight, preferably 2-3% by weight, as a precipitant for the resin adhesive. Surprisingly, the cationic polymers act as a binder for the non-reactive resin adhesive. Polymers of this type are known, for example, from the literature references mentioned in the prior art description US-PS 4 421 602 and EP-A-0 216 387. They are prepared by hydrolysis of homopolymers and copolymers containing N-vinylamides copolymerized.

Such polymers contain the following characteristic structures: -CH 2 -CH- a.

R C

Wherein R 1 and R 1 represent hydrogen or C 1-6 alkyl.

For the preparation of compounds containing exclusively the structural units of the formula I, e.g. N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinylpropionamide or N-vinyl-35-butyramide are polymerized. The compounds having the structural elements of the formula I are formed by hydrolysis on the use of acids, e.g. hydrochloric acid, sulfuric acid, phosphoric acid, or under the influence of bases, such as sodium hydroxide or potassium hydroxide, when the group -CO-R1 cleaves the following structure:

-CH2-CH-2 I

(II)

R 'H

10 wherein R is hydrogen or C 1-6 alkyl.

When all the units of structure I in the polymer are 100% hydrolysed, polyvinylamine is obtained. If only partial hydrolysis is performed, compounds of structures I and II are obtained from polymers prepared from N-vinylamides. Preferably, a compound of formula is used as the N-vinylamide

CHO

CH = CH-N 2 - (III),

20 ^ H

i.e. N-vinylformamide. Partially hydrolyzed homopolymers of compound III are known from the above-mentioned US-PS 4,421,602. The degree of hydrolysis can be between 0.1 and 100%. Preferably, the polymers containing vinylamine units copolymerized include compounds obtainable by copolymerizing a) 1 to 99, preferably 10 to 90 mol%, N-vinyl-formamide and. b) 99 to 1 mol% of monoethylenically unsaturated monomers selected from the group consisting of vinyl acetate, vinyl propionate, C 1-4 alkyl vinyl ethers, N-vinylpyrrolidone, esters of acrylic acid and methacrylic acid, N-nitriles, amitriles, amitriles alkylamides and N-alkylamides containing sulfo groups, as well as mixtures of these monomers, and then hydrolyzing the amide groups in the structural units I of the polymers to the amino groups of the structure II. The degree of hydrolysis of the polymerized N-vinylformamide units is between 0.1 and 100%, preferably at least 10%.

Such copolymers are described in EP-A-0 216 387. In addition to N-vinylformamide, e.g. N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide can be used as the monomer of component (a). amide, N-vinylpropionamide or N-vinylbutyramide. When hydrolysing copolymers prepared from N-vinylformamide and vinyl acetate or vinyl propionate, the copolymerized monomer units (b) can also be hydrolyzed, depending on the reaction conditions, so that the copolymers contain, in the case of the latter, e.g., vinyl alcohol units. The degree of hydrolysis of the acetyl and / or propionyl groups consisting of the copolymerized units (b) of the copolymers may be between 0.1 and 100%.

The K-25 values for the molecular weights of homopolymers and copolymers containing vinylamine units copolymerized were determined according to H. Fikentscher, Cellulose-Chemie, Part 18, 48-64 and 71-74 (1932) in 5% aqueous saline at 25 ° C and with a polymer concentration of 1% by weight. K values are between 5 and 300, preferably between 15 and 150. Particularly preferred are polyvinylamines and hydrolysed copolymers of N-vinylformamide with K values between 20 and 115.

Cationic polymers containing vinylamine units when polymerized are water soluble. They are added directly to the pulp to perform pulp sizing, or they can also be added to the pulp in the form of a mixture with resin glue. In the case of separate dosing of the polymer and the resin adhesive, it does not matter whether the resin adhesive or the cationic polymer is added to the pulp first, since sufficient mixing of the components always takes place in the pulp. 1 to 100, preferably 5 to 30 parts by weight, of at least one cationic polymer containing vinylamine units copolymerized are used per 100 parts by weight of the resin adhesive.

10 As fibers for the manufacture of stock, all grades suitable for this purpose are possible, such as wood pulp, bleached and unbleached cellulose, as well as papermaking materials derived from all annual plants. Wood pulps include, for example, groundwood, thermomechanical pulp (TMP), chemo-thermomechanical pulp (CTMP), pressure groundwood, semi-cellulose, high yield cellulose and Refiner Mechanical Pulp (RMP). Suitable celluloses are, for example, sulphate, sulphite and soda cellulose. Preferably, unbleached cellulose grades are used, also referred to as unbleached strength cellulose. Suitable annual plants for the production of pulps include, for example, rice, wheat, sugar cane and kenaf. Waste paper is also used to make pulps, either alone or in admixture with other fibrous materials. The pulps are mixed with a resin adhesive and at least one polymer used as an adhesive according to the invention to produce paper, cardboard and paperboard, and the water is removed in a known manner with a paper machine wire. The concentration of the pulps is between 0.1 and 1.5% by weight and the pH of the pulps is at most;

The parts indicated in the examples are parts by weight. Percentage data refer to percentages by weight of substances. K values were determined as described above. The qualities of the flavors were indicated by the Cobb value according to DIN 53 132 and the ink buoyancy time up to 50% throughput. To characterize the gluing, the absorption of the preparation was also determined. To this end, a strip of paper 5 (80 cm x 10 cm) was drawn through a laboratory adhesive press under constant pressure and at a speed of 10 meters / minute. Drinking water is used as the test liquid. From the weight gain, calculate the absorbence of the preparation as follows 10 (weight after gluing) - weight before gluing x 100

Absorption of valnlate * weight of dried sample (aba. Dry) 15 The following additives were used:

Adhesive 1 50% low viscosity resin soap made from chemically reinforced natural resins with a total resin acid number of 170, a free resin 20 content of about 2% and a viscosity according to Brookfield at 20 eC and 20 rpm of 1,000 mPas.

Fastener 1

A 11% aqueous solution of a copolymer containing 98% vinylamine units and 2% N-vinylformamide units and having a K value of 87. The pH of the aqueous solution was 3.5.

Fastener 2

A 12% aqueous solution (pH 30 3.5) of a copolymer containing 68% vinylamine, 2% N-vinylformamide, 25% vinyl alcohol and 5% vinyl acetate and having a K value of 105.

Fastener 3

A 17% aqueous solution of a copolymer containing 45% vinylamine and 55% N-vinylformamide units and having a K value of 87. The pH of the aqueous solution was 3.5.

8 97405

examples

A pulp containing 100% bleached birch sulphate cellulose is prepared by adding 40% chalk. The degree of grinding is 35 ° SR (Schopper-Riegler).

5 To this mass is added 1.5% by weight of adhesive, 3% by weight of alum, based on the solids content, and then 0.1% by weight of solids, based on one of the fixing agents mentioned in Tables 1 and 2. The pH of the pulp then remains unchanged at pH 7. In all 10 examples, 0.3% of a commercially available weakly cationic polyacrylamide with a K value of 130 was further added to the pulp as a retention aid, and sheets were then prepared on a Rapid-Köthen sheet machine. with a sheet weight of 100 g / m2. The sheets were in each case dried on 15 steam-heated drying cylinders at 90 ° C so that the residual moisture became 6-10%.

In all examples, the absorbance, Cobb value and ink buoyancy time of the preparation were determined immediately after drying. These results are summarized in Table 1.

The sheets were then stored for one day at 23 ° C and 50% relative humidity. The absorbance, Cobb value and ink buoyancy time of the preparation were then determined. The measurement results obtained in this case are shown in Table 2.

25 Comparative example

Example 1 was repeated with the only difference that instead of 0.1% by weight of fixing agent 1, only 3% by weight of alum was used as fixing agent and precipitant. The pH of the pulp was 7. The results obtained in this case are shown in Tables 1 and 2.

9 97405

Table 1: Instant gluing

Example Adhesive Cobb- Ink Absorption Value Floating Time (%) 60 "(min) 5 1 1 21.1 31> 60 2 2 22.5 51 30 3 3 21.1 41> 60

Comparative Example 1 alum 30.3 46 5

Table 2: Bonding after aging Example Adhesive Absorption value of Cobb Ink 15 floating time (%) 60 "(min) 1 1 18.5 46> 60 2 2 21.5 49> 30 20 3 3 17.9 41> 60

Comparative Example 1 1 31.2 64 1

Claims (6)

A method for performing pulp, paper, cardboard and cardboard bonding using resin adhesives and a fixing agent to fix the resin adhesive in cellulose fibers, characterized in that cationic polymers containing polymerized vinylamine units therein are used as fixing agents. 2. A process according to claim 1, characterized in that the hydrolyzed homopolymers of N-vinylformamide having a degree of hydrolysis of 0.1 - 100% are used as a fixing agent. 3. A process according to claim 1, characterized in that the hydrolyzed copolymers of N-vinylformamide which contain no more than 99 mole% ethylenically unsaturated, polymerized monomers selected from vinyl acetate, vinyl propionate, C 1-4 alkyl vinyl ethers, are used as the fixing agent. vinyl pyrrolidone, esters, nitriles and amides of acrylic acid or methacrylic acid, where the degree of hydrolysis of the N-vinylformamide units polymerized therein is between 0.1 and 100%. Process according to any one of claims 1-3, characterized in that hydrolyzed polymers obtained by polymerizing (a) 100 - 10 mole% N-vinylformamide and (b) 0 - 90 mole% are used as the fixing agent. vinyl acetate and / or vinyl propionate, and by then cleaving 0.1 to 100% of formyl groups from the copolymerized units (a) thereof. the lymers and optionally 0.1 - 100% acetyl and / or propionyl groups from the copolymerized units (b) therein of the copolymers. Process according to any one of claims 1-4, characterized in that for every 100 wt. 97405 parts of resin uses 10 to 300 parts by weight of at least one cationic polymer. 6. Use of cationic polymers containing therein polymerized vinylamine units as resin adhesive fixing agents for pulping of paper, cardboard and paperboard. * «