BE1026476B1 - PROCESS FOR PRODUCING PAPER OR BOARD PAPER, MORE SPECIFIC LABEL PAPER OR BOARD PAPER THAT CAN BE USED AS PACKAGING MATERIAL FOR DRINK CONTAINERS - Google Patents

Abstract

Method for producing label paper or ribbed cardboard or folding cardboard for packaging beverage containers, comprising the steps of: - supplying wood fiber pulp in a paper production process; - forming a non-woven mixture comprising the wood fiber pulp, a cationic polymer, an anionic polymer and a cationic starch; characterized in that the cationic starch is added to the wood fiber pulp only after the addition of the anionic polymer and cationic polymer.

Description

Process for producing paper or board paper, more specifically label paper or board paper that can be used as packaging material for beverage containers

FIELD OF THE INVENTION

The present invention relates to a process for producing paper or board paper, more specifically label paper or board paper that can be used as packaging material for beverage containers.

BACKGROUND OF THE INVENTION

Label paper and board paper that can be used as packaging material for beverage cans or bottles must meet specific requirements to ensure full functionality of the packaging material (secondary packaging material that typically holds 2 or more beverage containers such as cans or bottles together). The same applies to beverage labels that are intended to be glued on, for example, glass bottles.

The most important requirement for label paper is resistance to humidity because condensation can often occur on the outer surface of the beverage containers and beverage bottles are typically stored outside for longer periods of time. Clear exposure to moisture should not affect the quality of the label in terms of printability or affect the integrity of the label paper. Therefore, properties such as high wet tear resistance and high wet tensile strength are an important requirement of label papers.

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The same applies to cardboard designed for use as packaging material. Such a board paper must meet strict requirements of wet tensile strength and wet tear resistance because the structural integrity of the packaging must be ensured over the entire life of a solid (secondary) packaging product, otherwise the beverage container runs the risk of falling out of the packaging after lifting .

In industrial paper production, the use of wet strength additives is known and commonly used additives for this purpose include epichlorohydrin, melamine and urea formaldehyde.

Other typical wood pulp additives in the paper production process include: i) dry strength additives such as cationic starch; ii) binders for increasing printability such as carboxymethylcellulose; iii) retention aids that allow binding of fillers to the paper, such as polyacrylamide.

The present invention satisfies the above industrial requirements and provides a method that enables production of label paper and packaging board paper with increased wet tensile strength and wet tear resistance of paper while maintaining the basic weight of the paper / board paper.

Summary of the invention

The present invention relates to a method for producing label paper or

BE2018 / 5517 paper for ribbed cardboard or folding cardboard for packaging beverage containers, comprising the steps of:

- supplying wood fiber pulp in a paper production process;

^- forming a non-woven mixture comprising the wood fiber pulp, a cationic polymer, an anionic polymer and a cationic starch;

characterized in that the cationic starch is added to the wood fiber pulp only after the addition of the anionic polymer and cationic polymer.

The cationic polymer is preferably added to the wood fiber pulp before the addition of the anionic polymer.

According to a preferred method of the invention, the cationic polymer comprises or is polyamide amine epichlorohydrin (PAE), which is added to the wood fiber pulp in an amount between 1 and 40 kg / ton wood fiber pulp (dry weight), preferably between 1.5 and 4.5 kg / ton wood fiber pulp (dry weight).

The anionic polymer preferably comprises carboxymethyl cellulose (CMC), which can be added to the wood fiber pulp in an amount between 0.1 and 10 kg / ton wood fiber pulp (dry weight), preferably between 0.5 and 2 kg / ton wood fiber pulp (dry weight).

The amount of cationic starch added to the wood fiber pulp is preferably between 1 and 40 kg / ton wood fiber pulp (dry weight), more preferably between 5 and 15 kg / ton wood fiber pulp (dry weight).

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The method of the present invention preferably comprises providing a reaction time between adding cationic polymer and adding anionic polymer to the fleece blend of wood fiber pulp and / or providing a reaction time between adding anionic polymer and adding cationic starch to the non-woven blend of wood fiber pulp.

The present invention also relates to a fiber product comprising:

a non-woven fabric; and an at least partially cured resin composition, wherein, before curing, the resin composition comprises:

a polyamide-epichlorohydrin resin;

a carboxymethyl cellulose; and cationic starch.

The fiber product according to the present invention preferably has a wet tensile strength of at least 7 Nm / g (ISO3781: 2011) and / or a wet tear resistance of at least 9 mN'm ² / g, preferably at least 9.5 mN'm2 / g (ISO1794: 2012).

Brief description of the drawings

Figures 1 and 2 illustrate two alternative process schemes of a method according to the present invention;

Figure 3 shows an arrangement of a forming section of a paper production device that can be used in a method according to the present invention;

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Figures 4 to 10 show features of specific fiber products made during test runs of the method of the present invention.

Description of a preferred embodiment

The present invention relates to a method for producing label paper or ribbed cardboard or folding cardboard for packaging beverage containers, comprising the steps of:

- supplying wood fiber pulp in a paper production process;

^- forming a non-woven mixture comprising the wood fiber pulp, a cationic polymer, an anionic polymer and a cationic starch;

characterized in that the cationic starch is added to the wood fiber pulp only after the addition of the anionic polymer and cationic polymer.

Figures 1 and 2 show two alternative preferred process schemes of a method according to the present invention, wherein in Figure 1 the chemical substances, more specifically a cationic polymer (such as polyamideamine epichlorohydrin (PAE)); an anionic polymer (preferably comprising carboxymethyl cellulose (CMC)); and cationic starch are metered in line to the substance composition between a front box and a main box. In Figure 2, the chemical substances are again sequentially metered in the substance composition to a storage case for the substance composition, downstream of the front crate and the further downstream main bin.

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Both process schemes were used for some paper production test runs as will be described in more detail below. Raw materials and application of chemical substances

In the test versions a fabric composition was used consisting of 80% "southern pine, Alabama river" and 20% hard wood (birch). The pulp mixture was refined in one batch to grinding grade 495 ml (refined 1000 kg in Valmet, Rautpohja). This substance composition is indeed given purely as an example; various variants can be used without departing from the present invention.

The chemical used substances for the test executions were: PAE: Kymene 25 X-cell I ; Solenis), 1.5, 3.0 or 4.5 kg / ton • CMC: Finnfix 5 (CP Celco), 1.0 or

2.0 kg / ton • Cationic starch: Raisamyl 50021 (Chemigate), 5 or 15 kg / ton • Retention aid: cationic polyacrylamide cPAM, Fennopol 3400 (Kemira), 200 g / ton

The chemicals were alternatively dosed in line before the main bin (Fig. 1) or to the batch of substance composition (Fig. 2).

In the in-line addition of the chemical substances (Fig. 1), the interaction time between chemical substances with each other and the pulp mixture (or substance composition) was several seconds, while in batch dosages (Fig. 2) the interaction time was several

BE2018 / 5517 minutes. In both cases, the addition order of the chemicals was the same: 1. PAE (cationic polymer), 2. CMC (anionic polymer), 3. Cationic starch, 4. C-PAM (retention aid). The addition sites and interaction time of additives before the formation section (main bin) are presented in schematic layout images of in-line dosing (Fig. 1) and batch dosing (Fig. 2).

Setup and run parameters of the training section

The pilot device consists of a feed-in system with different types of containers, a forming section (Fig. 3) that can operate in slit, hybrid or four-wheel mode, and from a press section (not shown). In the test execution, the pilot device operated in the hybrid formation mode at a speed of 400 m / min. The consistency of the dust composition in the main bin was 0.6%. The formation section configuration is shown in Figure 3.

The pressing section (Fig. 3) consisted of a shoe press with 1 filling gap with an extended gap of 350 mm. The filling gap pressure was set in three different levels: 400, 800 and 1200 kN / m. After wet pressing, the paper web was reeled in and sheet samples were taken and dried in a cylinder dryer for laboratory analyzes.

Measurements of screen cloth water, dust composition in the main body, wet fleece and dry sheet

Process conditions and process inputs were measured and recorded in line in a Wedge data acquisition system.

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To make it easier to display the results, the geometric mean values of the data in machine direction (MD) and cross direction (CD) were measured. Produced conditions

Various conditions were produced and sampled in the test run on the pilot device. The complete 22 test points are shown in Table 1. During the test runs, some test points were rejected on the basis of a too low or 10 too high basis weight (missing figures in Table 1).

Day Condition Test point Additions Online - PAE to the previous front box Online - CMC to between main container and sieve AER, PAE Kymene 25 X-Cell dosage PAE addition consistency (25% active material content) CMC, Finnfix 5 dosage Starch addition consistency [%] [kg / tn] [%] [kg / tn] [%] 1 Reference 1 - - - - 1 In line dosage 2 1.5 0.5 - - 1 Reference 3 - - - - 1 In line dosage 4 1.5 0.5 1.0 0.35 New furnish 1 Reference 5 - - - - 1 In line dosage 6 3.00 0.5 1 Reference 9 - - - - 1 In line dosage 10 3.00 0.5 2.0 0.35 New furnish 1 Reference 12 - - - - 1 In line dosage 14 4.5 1 - -

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1 Reference 15 - - - - 1 In line dosage 16 4.5 1 2.0 0.35 1 In line dosage 17 4.5 1 2.0 0.35 PAE, kg / tn Batch - PAE to second wire pit CMC, kg / tn Batch - CMC to second wire pit Batch treatment addition consistency% Batch treatment addition consistency% First -10 minutes treatment time Second -15 minutes of treatment time 2 Transit tests 18 3.0 1.0 - - 2 Transit tests 19 3.0 1.0 - - 2 Transit tests 20 3.0 1.0 - - 2 Transit tests 21 3.0 1.0 - - New furnish 2 Transit tests 22 3.0 1.0 2 0.35 2 Transit tests 23 3.0 1.0 2 0.35 2 Transit tests 24 3.0 1.0 2 0.35 2 Transit tests 25 3.0 1.0 2 0.35 2 Transit tests 26 3.0 1.0 2 0.35 NOTE: 20 sheets / test point, heat treatment of the dry samples; 10 min in 105C

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Day Condition Test point Online starch to retention aid mixer mixer further to main container C-PAM to retention aid mixer closer to main bin Pressure Starch, Raisamyl 50021 dosage Starch addition consistency [%] C-PAM Fennopol 3400 Line load [kg / tn] [%] [g / tn] [kN / m] 1 Reference 1 - - 200 800 1 In line dosage 2 5 1.1 200 800 1 Reference 3 - - 200 800 1 In line dosage 4 5 1.1 200 800 New furnish 1 Reference 5 - - 200 800 1 In line dosage 6 15 1.1 200 800 1 Reference 9 - - 200 800 1 In line dosage 10 15 1.1 200 800 New furnish 1 Reference 12 - - 200 800 1 In line dosage 14 15 1.1 200 800 1 Reference 15 - - 200 800 1 In line dosage 16 15 1.1 200 800 1 In line dosage 17 15 1.1 200 800 Starch, kg / tn Batch - CMC to second wire pit C-PAM, g / tn Batch treatment addition consistency% Third - 30 minutes Online 2 Transit tests 18 15 1.1 200 800 2 Transit tests 19 15 1.1 200 1200 2 Transit tests 20 15 1.1 200 400

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2 Transit tests 21 15 1.1 200 800 New furnish 2 Transit tests 22 15 1.1 200 800 2 Transit tests 23 15 1.1 200 1200 2 Pass-through screws 24 15 1.1 200 400 2 Transit tests 25 15 1.1 200 800 2 Pass-through screws 26 15 1.1 200 800 NOTE: 20 sheets / test point, heat treatment of the dry samples; 10 min in 105C

Substance composition analyzes

The pH or conductivity of the substance composition was not chemically modified in the test embodiments. The pH of the substance composition (measured from the substance composition steel in the main bin) was between 7.7 and 8.1 at all test points. PAE (wet strength agent) is known to work best in an area with neutral or alkaline pH. Accordingly, the conductivity was ~ 180 pS at all test points. The pH and conductivity values were very close to what was used in the preliminary laboratory scale studies.

The grinding degree of the original refined pulp mixture was 475 ml. Figure 4 shows grinding degree values that were measured from the dust composition samples taken from the main bin. On the day of in-line dosing, the grinding degree value was at a level of up to approximately 500 ml. Bee

BE2018 / 5517 the first test points (only reference points measured) 1 and 3 were probably less finely washed in the white water when the pulp was recycled in the pilot installation compared to the test points from 5 to 15. On the day with batch dosing (throughput tests), new fresh pulp and water were refreshed after the implementation of reference point 18, so that the basis of the substance composition in 18 and 22 should be comparable.

Beta formation

Figure 5 shows that the method of the present invention did not significantly affect the beta formation values. The fabric composition consisted of 80% very long Pinus palustris fibers, so that increased flocculation of the fabric composition would be noticeable with a strong increase in the beta formation value. Because the formation remained at the same level, no significant changes in coatability or printability of the product were expected if the new reinforcement solution were used in the paper / board mills.

Dewatering characteristics

In Figures 6 and 7, dryness value after the forming section and the pressing section are represented. As for the line dosing test points, the method of the present invention had only little effect on the total vacuum level in the forming section (no samples were taken on the day of the batch dosing test). Accordingly, the dryness after wet pressing was not significantly changed by the method of the present invention to line or batch dosing points.

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Structural features

The average gram weight of the test points (Figure 8) was 100 ± 5 g / m2 in in-line dosing points. In the batch dosing test points (throughput tests) the grammage lower was 91 ± 3 g / m2. Additionally, a very low grammage test point 53 g / m2 was performed. The low-gram weight test point offers the possibility of determining the probability of reducing gram weight with the method according to the present invention.

The method of the present invention had no significant impact on the volume of the sheet. Therefore, no change in the bending resistance of the product is expected. Furthermore, in the batch dosing test points, the air permeability was not changed by the method of the present invention. Wet sheet strength properties

The conventional wet and dry strength solution: PAE with starch was found to increase the wet crack index to 250% compared to reference without reinforcement aids. The method of the present invention further increased the wet crack resistance by 28% (Fig. 9). The results show that in line dosing with short interaction times of the chemicals might be possible. Similarly, the method of the present invention increased the tensile index (16%). (Fig 10)

decide

A method according to the present invention has demonstrated no or no significant influence on dewatering in forming and pressing sections.

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Additionally, skin formation was not affected by the dosing strategy of the chemical substances of the present invention. The results show that wet drying enhancers can be applied in line or batch dosing systems.

In general, it was demonstrated in the pilot studies that the method of the present invention can provide qualitative advantages to the end product compared to conventional reinforcement solution. Wet strength properties of the sheet increased significantly (wet crack index +28% and wet tensile index +16%). Alternatively, the grammage could be reduced by 25% (from 95 to 70 g / m2) without a reduction in wet tear strength.

The above characteristics make the fiber product of the present invention suitable for use as label paper or ribbed cardboard or folding carton for packaging beverage containers, where wet tear strength and wet pull strength are important properties.

Claims (10)

Conclusions 1. - Method for producing label paper or ribbed cardboard or folding cardboard for packaging beverage containers, comprising the steps of: ^- supplying wood fiber pulp in a paper production process; ^- forming a non-woven mixture comprising the wood fiber pulp, a cationic polymer, an anionic polymer and a cationic starch; characterized in that the cationic starch is added to the wood fiber pulp only after the addition of the anionic polymer and cationic polymer. The method of claim 1, wherein the cationic polymer is added to the wood fiber pulp prior to the addition of the anionic polymer. The method of claim 1 or 2, wherein the cationic polymer contains polyamide amine epichlorohydrin (PAE). The method of claim 3, wherein the amount of PAE added to the wood fiber pulp is between 1 and 40 kg / ton wood fiber pulp (dry weight), more preferably between 1.5 and 4.5 kg / ton wood fiber pulp (dry weight) ) lies. The method of any one of the preceding claims, wherein the anionic polymer comprises carboxymethyl cellulose (CMC). The method of claim 5, wherein the amount of CMC added to the wood fiber pulp is between 0.1 and 10 kg / ton wood fiber pulp (dry weight), with BE2018 / 5517 is more preferably between 0.5 and 2 kg / ton wood fiber pulp (dry weight). A method according to any one of the preceding claims, wherein the amount of cationic starch added to the wood fiber pulp is between 1 and 40 kg / ton wood fiber pulp (dry weight), more preferably between 5 and 15 kg / ton wood fiber pulp (dry weight) lies. A method according to any one of the preceding claims, comprising providing a reaction time between the addition of cationic polymer and the addition of anionic polymer to the non-woven blend of wood fiber pulp. A method according to any one of the preceding claims, comprising providing a reaction time between the addition of anionic polymer and the addition of cationic starch to the non-woven blend of wood fiber pulp. 10. - Fiber product containing: a non-woven fabric; and an at least partially cured resin composition, wherein, before curing, the resin composition comprises: a polyamide-epichlorohydrin resin; a carboxymethyl cellulose resin; and cationic starch, in which the cationic starch is added after the addition of the polyamide-epichlorohydrin resin and the carboxymethyl cellulose resin, and wherein the fiber product has a wet tensile strength of at least 7 N'm / g (ISO3781: 2011) and / or wherein the fiber product has a wet resistance BE2018 / 5517 of at least 9 mN'm ² / g, preferably at least Has 9.5 mN’m2 / g (ISO1794: 2012).