阅读说明：本技术 用于生产纸或纸板、特别是适合用作饮料容器的包装材料的标签纸或纸板的方法，以及通过该方法生产的纸或纸板 (Method for producing paper or paperboard, in particular label paper or paperboard suitable for use as packaging material for beverage containers, and paper or paperboard produced by the method ) 是由 雅诺-彼得里·梅里萨洛 于 2019-07-17 设计创作，主要内容包括：本发明涉及生产用于包装饮料容器的标签纸或用于瓦楞纸板的纸或折叠纸盒的方法,包括步骤：-将木纤维纸浆送入造纸工艺；-形成网状混合物,该网状混合物包含木纤维纸浆、阳离子聚合物、阴离子聚合物和阳离子淀粉；其特征在于,在添加阴离子聚合物和阳离子聚合物之后才将阳离子淀粉添加到木纤维纸浆中。(The present invention relates to a method of producing a label paper for packaging beverage containers or a paper or a folded carton for corrugated board, comprising the steps of: -feeding the wood fibre pulp to a papermaking process; -forming a reticulated mixture comprising a wood fiber pulp, a cationic polymer, an anionic polymer, and a cationic starch; characterized in that the cationic starch is added to the wood fibre pulp after the addition of the anionic polymer and the cationic polymer.)

1. A method of producing a label paper or corrugated board or folding carton for packaging beverage containers, comprising the steps of:

-feeding the wood fibre pulp to a papermaking process;

-forming a reticulated mixture comprising the wood fiber pulp, cationic polymer, anionic polymer and cationic starch;

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

2. The method according to claim 1, characterized in that the cationic polymer is added to the wood fiber pulp before the anionic polymer is added.

3. The process according to claim 1 or 2, characterized in that said cationic polymer comprises polyamide epichlorohydrin (PAE).

4. The method according to claim 3, wherein the amount of PAE added to the wood fiber pulp is 1-40 kg/ton wood fiber pulp (dry weight), preferably 1.5-4.5 kg/ton wood fiber pulp (dry weight).

5. The method of any of the preceding claims, wherein the anionic polymer comprises carboxymethyl cellulose (CMC).

6. The method according to claim 5, characterized in that the amount of CMC added to the wood fiber pulp is 0.1-10 kg/ton wood fiber pulp (dry weight), preferably 0.5-2 kg/ton wood fiber pulp (dry weight).

7. The method according to any of the preceding claims, characterized in that the amount of cationic starch added to the wood fiber pulp is 1-40 kg/ton wood fiber pulp (dry weight), preferably 5-15 kg/ton wood fiber pulp (dry weight).

8. The method according to any of the preceding claims, characterized in that the method comprises providing a reaction time between adding the cationic polymer and adding the anionic polymer to the reticulate mixture of the wood fiber pulp.

9. The method according to any of the preceding claims, characterized in that the method comprises providing a reaction time between adding the anionic polymer and adding the cationic starch to the networked mixture of the wood fiber pulp.

10. A fibrous product comprising:

a fiber web; and

an at least partially cured resin composition, wherein, preferably prior to curing, the resin composition comprises:

a cationic polymer, preferably a polyamide epichlorohydrin;

an anionic polymer, preferably carboxymethyl cellulose; and

cationic starch, wherein the cationic starch is added after the addition of the anionic polymer and the cationic polymer, characterized in that the fiber product has a wet tensile strength of at least 7N-m/g (ISO 3781: 2011) and/or at least 9 mN-m²Per g, preferably at least 9.5mN m²Wet tear resistance in terms of/g (ISO 1794: 2012).

Technical Field

The present invention relates to a process for producing paper or paperboard, in particular label paper or paperboard suitable for use as packaging material for beverage containers.

Background

Label paper and paperboard suitable as packaging material for beverage cans or beverage bottles need to meet specific requirements to ensure the full functionality of the packaging material (secondary packaging materials typically hold 2 or more beverage containers (e.g. cans or bottles) together). The same is true of beverage labels intended to be stuck on, for example, glass bottles.

The main requirement for label paper is moisture resistance, as condensation often occurs on the outer surface of beverage containers, and beverage bottles are often stored outdoors for extended periods of time. In terms of printability, significant exposure to moisture should not affect label quality nor compromise the integrity of the label paper. Therefore, high wet tear resistance and high wet tensile strength properties are the main requirements for label paper.

The same is true of paperboard designed for use as packaging material. Such a paperboard should meet stringent requirements with regard to wet tensile strength and wet tear resistance, since the structural integrity of the package is ensured throughout the service life of such a (secondary) packaged product, otherwise the beverage container risks falling out of the package when lifted.

The use of wet strength additives in industrial papermaking is well known, and common additives used for this purpose include epichlorohydrin, melamine and urea formaldehyde.

Other typical additives to wood pulp in the papermaking process include: i) dry strength additives, such as cationic starch; ii) a printability enhancing binder, such as carboxymethyl cellulose; iii) retention aids for binding the filling material to the paper, such as polyacrylamides.

The present invention addresses the above-mentioned industry needs and provides a method that allows the production of label paper and packaging board with increased wet tensile strength and wet tear resistance of the paper while keeping the paper/board basis weight constant.

Disclosure of Invention

The present invention relates to a method of producing a label paper for packaging beverage containers or a paper or a folded carton for corrugated board, comprising the steps of:

-feeding the wood fibre pulp to a papermaking process;

-forming a reticulated mixture comprising a wood fiber pulp, a cationic polymer, an anionic polymer, and a cationic starch;

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

Preferably, the cationic polymer is added to the wood fibre pulp before the anionic polymer is added.

According to a preferred method of the invention, the cationic polymer comprises polyamide epichlorohydrin (PAE) or the cationic polymer is PAE, and the PAE added to the wood fibre pulp is 1-40 kg/ton wood fibre pulp (dry weight), preferably 1.5-4.5 kg/ton wood fibre pulp (dry weight).

The anionic polymer preferably comprises carboxymethyl cellulose (CMC), the CMC added to the wood fibre pulp being 0.1-10 kg/ton wood fibre pulp (dry weight), preferably 0.5-2 kg/ton wood fibre pulp (dry weight).

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

The method of the present invention preferably comprises providing a reaction time between the addition of the cationic polymer and the addition of the anionic polymer to the networked mixture of wood fiber pulp and/or providing a reaction time between the addition of the anionic polymer and the addition of the cationic starch to the networked mixture of wood fiber pulp.

The invention also relates to a fibrous product comprising:

a fiber web; and

an at least partially cured resin composition, wherein, preferably prior to curing, the resin composition comprises:

cationic polymers, preferably polyamide epichlorohydrin (resins);

anionic polymers, preferably carboxymethylcellulose (resin); and

cationic starch, wherein the cationic starch is added after the addition of the anionic polymer and the cationic polymer.

In a preferred embodiment, the PEC polymer is a PEC resin.

In a preferred embodiment, the CMC polymer is a CMC resin.

Note that the term "curing" refers to a step of mixing a chemical (resin composition) with the fiber (fiber web).

The fibre product according to the invention preferably has a wet tensile strength of at least 7 N.m/g (ISO 3781: 2011) and/or at least 9 mN.m²Per g, preferably at least 9.5mN m²Wet tear resistance in terms of/g (ISO 1794: 2012).

Drawings

Figures 1 and 2 show two alternative process variants of the method according to the invention;

figure 3 shows a mechanism of a forming section of a paper machine usable in the method according to the invention;

fig. 4 to 10 show the properties of specific fiber products produced during the test of the method of the invention.

The following components are shown in the drawings:

1: white pit (Wire pit) 2: front groove 3: storage tank

4: headbox pump 5: and (6) screening: head box

7: raw fiber 8: fiber returning groove 9: driven roller

10: steering guide, tension measurement 11: high vacuum

12: friction measurement vacuum box 13: transfer vacuum box

14: vacuum box 115: the MB unit 16: skirtboard

Detailed Description

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

-feeding the wood fibre pulp to a papermaking process;

-forming a reticulated mixture comprising a wood fiber pulp, a cationic polymer, an anionic polymer, and a cationic starch;

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

Fig. 1 and 2 show two alternative preferred process variants of the method according to the invention, wherein in fig. 1 the chemicals, in particular: cationic polymers (e.g., polyamide epichlorohydrin (PAE)); an anionic polymer (preferably comprising carboxymethylcellulose (CMC)); and cationic starch, in-line feeding (pedestal) to the furnish (furnish) between the headbox and the headbox. In fig. 2, the chemicals are fed into the furnish sequentially and in batches to the stock tank, the headbox downstream and further downstream of the headbox of the furnish.

Both of these process schemes are used in some papermaking trials, as discussed in detail below.

Use of raw materials and chemicals

In the tests, a furnish consisting of 80% southern pine, alabama river and 20% hardwood (birch) was used. The pulp mixture was refined in one batch to a freeness of 495ml (1000 kg in vimet (Valmet) of Rautpohja). Obviously, this ingredient is provided as an example only, as many variations are possible without departing from the invention.

The chemicals used for the tests were:

PAE: kymene 25X-cel (solenis), 1.5 kg/ton, 3.0 kg/ton or 4.5 kg/ton

CMC: finnfix 5(CP Celco), 1.0 kg/ton or 2.0 kg/ton

Cationic starch: raisamyl 5002(Chemigate), 5 kg/ton or 15 kg/ton

Retention aids: cationic Polyacrylamide cPAM, Fennopol 3400(Kemira), 200 g/ton

Alternatively, the chemicals are fed in-line (fig. 1) or to the batch (fig. 2) before the headbox.

The interaction time between chemicals with each other and with the pulp mixture (or furnish) is a few seconds when the chemicals are added on-line (fig. 1), and a few minutes when fed in batches (fig. 2). In both cases, the order of addition of the chemicals is the same: PAE (cationic polymer), 2 CMC (anionic polymer), 3 cationic starch, 4C-PAM (retention aid). The additive addition location and interaction time before the forming section (headbox) are shown in the schematic layout of the in-line feed (fig. 1) and the batch feed (fig. 2).

Forming section setup and operating parameters

The leader is composed of a streaming system having: different kinds of containers; a forming section (fig. 3) operable in a gap, hybrid or fourdrinier mode; and a press section (not shown). In the test, the pilot machine was run in a hybrid forming mode at a speed of 400 m/min. The consistency of the furnish in the headbox was 0.6%. The configuration of the molding portion is shown in fig. 3.

The press section (fig. 3) consisted of a 1-nip shoe press (1-nip press) with an extended nip of 350 mm. Nip pressure varies at three different levels: 400kN/m, 800kN/m and 1200 kN/m. After wet pressing, the web was rolled up, and a sample of paper (sheet) was collected and dried in a tumble dryer for laboratory analysis.

Measurement of line water, furnish in headbox, wet and dry paper

The process conditions and process inputs are measured and recorded online in the Wedge data acquisition system.

To make viewing of the results easier, geometric averages are calculated from Machine Direction (MD) data and Cross Direction (CD) data.

Production conditions

Different conditions were generated and sampled in pilot machine experiments. A total of 22 test points are listed in table 1. During the test, some test points were rejected due to too low or too high basis weights (missing numbers in table 1).

Watch 1 (watch divided into two parts)

Ingredient analysis

In the test, no chemical modification was made to the pH or conductivity of the furnish. The pH of the furnish (measured from the headbox furnish sample) was 7.7 to 8.1 at all test points. It is well known that PAE (wet strength agent) works best in the neutral or alkaline pH region. Accordingly, the conductivity in all test points was 180. mu.S. The pH and conductivity values were very close to those applied in the preliminary laboratory scale experiments.

The drainage of the original refined pulp mixture was 475 ml. The drainage values measured in a sample of furnish taken from the headbox are shown in fig. 4. On the day of on-line addition, the level of the freeness value was found to reach about 500 ml. At the first test point (only the reference point was measured), when the pulp was circulated in the pilot test, 1 and 3 are likely to be less finely rinsed to the white water than at the test points of 5 to 15. On the dosing day (throughout the test), new fresh pulp and water were replaced after running reference point 18, and therefore the furnish base in 18 and 22 should be comparable.

Beta forming

It can be seen in fig. 5 that the method of the present invention does not significantly affect the beta-formation value. 80% of the furnish consists of very long southern pine fibers, therefore, an increase in the degree of flocculation of the furnish will be seen in greatly increased beta-formation values. Since formation remains at the same level, it is expected that the coating properties or printability of the product will not change significantly when using the new strength aid solution in a paper/board mill.

Characteristics of dewatering

The dryness values after the forming section and the pressing section are given in fig. 6 and 7. Based on the on-line feeding test point, the method of the invention had only a small effect on the total vacuum level in the forming section (not counting samples from the batch feeding test day). Accordingly, the drying after wet pressing is not significantly changed in the on-line or fed-batch test point by the process according to the invention.

Structural features

In the in-line addition point, the average grammage of the test point (FIG. 8) was 100. + -.5 g/m 2. In the fed-batch test point (throughout the test), the grammage was below 91. + -.3 g/m 2. In addition, a very low grammage test point of 53g/m2 was performed. The low grammage test point provides the possibility of making a preliminary estimate of the potential for grammage reduction using the method according to the invention.

The process according to the invention has no significant effect on the volume of the paper. Thus, no change in the flexural strength of the product is expected. Furthermore, in the fed-batch test point, the air permeability coefficient was not changed by the method of the present invention.

Wet paper strength Properties

Conventional dry and wet strength protocol: the starch-containing PAE was found to increase the wet tear index to 250% compared to the reference without the strength aid. The method according to the invention further improves the wet tear resistance by 28% (fig. 9). The results show that on-line feeding with short interaction time with chemicals is possible. Also, the process according to the invention increased the wet tensile index (16%) (fig. 10).

Conclusion

It was found that the method according to the invention has no or no significant effect on the dewatering in the forming section and the press section. In addition, paper formation is not affected by the addition strategy of the chemicals of the present invention. The results show that wet strength aids and dry strength aids can be used in an online or fed-batch system.

Overall, it was demonstrated in pilot experiments that the process of the present invention can deliver end product quality benefits over conventional strength aid solutions. The wet strength performance of the paper is significantly improved (wet tear index + 28%, wet tensile index + 16%). Alternatively, without reducing wet tear strength, the grammage can be reduced by 25% (from 95g/m2 to 70g/m 2).

The above-mentioned features make the fibrous product according to the invention suitable for use as label paper or corrugated board or folding carton for packaging beverage containers, wherein wet tear strength and wet tensile strength are key features.