JP7062887B2 - Fiber composition test method for paper products or pulp - Google Patents

Description

The present invention relates to a fiber composition test method for a paper product or pulp.

The composition of softwood bleached kraft pal (NBKP), hardwood bleached kraft pulp (LBKP) and their tree species to be blended with paper is not only the strength characteristics of paper such as tensile strength, fold-resistant color burst strength, and tear strength. It is very important to know the fiber length and its distribution in the quality design of paper because it greatly affects the characteristics such as pore size distribution and air permeability. Therefore, when producing paper, a plurality of types of pulp are often used, and the pulp fiber blending ratio is one of the important points in the design of paper.

The fiber content of paper products or pulp is generally analyzed by a measuring method in which fibers stained with the C stain specified in JIS P8120: 1998 are observed under an optical microscope. However, since it is inevitable that individual differences will occur in the values obtained by this method, it is currently desired to develop a method that can be objectively judged.

A fiber measurement method by an optical automatic analysis method that can automatically measure fiber analysis such as fiber length and fiber width is known. There are two types of this fiber measurement method, a polarizing method and a non-polarizing method. However, the fiber measuring method by the optical automatic analysis method cannot always obtain the fiber compounding ratio with high accuracy.

JIS P8120: 1998, Paper, Paperboard and Pulp Fiber Composition Test Method (1998) JIS P8226: 2006, Fiber length measurement method by pulp mono-optical automatic analysis method Part 1: Polarization method (2006) JIS P8226-2: 2011, Pulp-Fiber length measurement method by optical automated analysis Part 2: Non-polarization method (2011)

An object of the present invention is to provide a fiber composition test method capable of objectively measuring the compounding ratio of pulp fibers in a paper product or pulp.

As a result of diligent research to achieve the above object, the present inventors have used softwood pulp and hardwood pulp whose tree species and beating degree are the same as those of the paper product or pulp to be tested, as a control, and the softwood pulp in the test subject. By calculating the ratio with hardwood pulp, it was found that the compounding ratio of pulp fiber can be objectively measured with sufficient accuracy.

The present inventors have further studied based on these findings and have completed the present invention.

That is, the present invention includes aspects.

[1] The fiber composition of the paper product or pulp for calculating the ratio of the softwood pulp and the broadleaf pulp in the test subject, using the softwood pulp and the broadleaf pulp having the same tree species and beating degree as the paper product or pulp of the test subject as a control. Test method.

[2] A paper product or pulp for which the ratio of softwood pulp to broadwood pulp in the paper, paperboard, or pulp to be tested is calculated using the softwood pulp and broadwood pulp immediately after the beating step during the manufacturing process as controls. Fiber composition test method.

[3] The method according to [1] or [2], wherein the ratio of the softwood pulp to the hardwood pulp in the test subject is calculated based on the fiber length measuring method by the optical automatic analysis method.

[4] The method according to any one of [1] to [3], wherein the ratio of the softwood pulp to the hardwood pulp in the test subject is calculated based on the fiber length measuring method by the non-polarization method.

[5] The method according to any one of [1] to [4], wherein the coefficient of variation is 3% or less.

[6] A quality control method in a paper manufacturing process, which comprises a step of calculating the ratio of softwood pulp to hardwood pulp in a test subject by the method according to any one of [1] to [5].

[7] A method for manufacturing a paper product, which comprises a step of performing quality control by the quality control method according to [6].

INDUSTRIAL APPLICABILITY The present invention provides a fiber composition test method capable of objectively measuring the compounding ratio of pulp fibers in a paper product or pulp. Although the method of the present invention is simple, the fiber compounding ratio can be obtained with higher accuracy than the conventional optical microscopy.

The present invention provides a method for testing a fiber composition of a paper product or pulp.

According to the fiber composition test method of the present invention, the blending ratio of the raw material pulp of the paper product or pulp to be tested is determined. Specifically, the blending ratio of softwood pulp (softwood bleached kraft pulp, NBKP) and hardwood pulp (hardwood bleached kraft pulp, LBKP) is obtained with an accuracy equal to or higher than that of the conventional method JIS P8120: 1998. .. The blending ratio is the ratio of the dry mass of the softwood pulp and the hardwood pulp.

The paper products subject to the method of the present invention include all grades and types of paper products made from cellulose pulp as a main raw material. For example, printing paper such as book paper, newspaper paper, gravure paper, art paper, coated paper, cast paper, and finely coated paper; writing paper such as notebook paper; wrapping paper; pressure-sensitive recording base paper, heat-sensitive recording paper, electrostatic Information paper such as recording paper and inkjet recording paper; special paper such as tack paper is exemplified, but the present invention is not limited thereto.

The method of the present invention can also be tested on cellulose pulp, which is a raw material for paper products. The pulp may be either dry pulp or slurry (slush) pulp.

In a preferred embodiment of the present invention, the blending ratio (N / L ratio) of the softwood pulp and the hardwood pulp of the paper product or pulp is about 10/90 to 90/10 or 20/80 to 80 on a mass basis. It is about / 20, or about 30/70 to 70/30, or about 40/60 to 60 to 40. In such a range, the N / L ratio can be obtained with particularly high accuracy as compared with the conventional method.

In the fiber composition test method of the present invention, softwood pulp and hardwood pulp having the same tree species and beating degree as the paper product or pulp to be tested are used as controls.

"Matching tree species" means that even the species in the angiosperm classification system of the tree from which coniferous pulp or hardwood pulp is derived are matched. For example, Eucalyptus genus (E. globulus), Eucalyptus camaldulensis (E. camaldulensis), Eucalyptus brushana (E. . brassiana), Eucalyptus tereticornis (E. tereticornis, E. grandis), Eucalyptus saligna (E. saligna), Eucalyptus deglputa (E. deglputa), Eucalyptus perita (E. pellita), Eucalyptus Eucalyptus (E. urophylla) is a different species, and the tree species do not match.

The degree of beating can be expressed by the Canadian standard freeness method specified in JIS P8121-2: 2012. "Matching beats" means that the difference between the control pulp and the current amount of pulp of the paper product or pulp under test is less than or equal to a predetermined threshold. As the threshold value, the difference from the average of the measured values can be less than 2% based on the Canadian standard freeness method.

In one aspect of the present invention, softwood pulp and broadleaf wood pulp immediately after the beating step during the manufacturing process can be used as controls.

In a normal paper product manufacturing process, raw material softwood pulp and hardwood pulp that have been appropriately bleached and washed are beaten to a desired degree of beating in the beating step. For example, in coated paper, if no beating or only light beating is performed, the bond strength between pulp fibers may decrease and the strength of the coated paper may decrease, while if the beating is advanced too much. Although the strength of the coated paper increases, the water extraction efficiency in the former section or the press section tends to decrease significantly.

After the pulp has undergone a beating step, softwood pulp and hardwood pulp are mixed in a desired blending ratio and sent to a paper machine as a paper material which is a slurry-like pulp water dispersion. A filler or an internal aid for papermaking may be added to this paper charge as needed.

"Coniferous wood pulp and broadleaf wood pulp immediately after the beating process during the manufacturing process" means softwood pulp and broadleaf tree pulp immediately after the beating process and immediately before being mixed.

In the present invention, the paper product or pulp to be tested is dissociated and subjected to the test. Methods of dissociating paper products or pulp are known. For example, it can be performed according to JIS P8120: 1998.

The blending ratio of the raw material pulp to be tested can be calculated by a known method using the above control. In a preferred embodiment of the present invention, the blending ratio of the raw material pulp can be determined based on the result of the fiber length measuring method by the optical automatic analysis method. The physical property values measured by the fiber measuring method by the optical automatic analysis method are, for example, fiber length (fiber length distribution), fiber width (fiber width distribution) and the like. There are two types of fiber measurement methods by the optical automatic analysis method, the polarization method and the non-polarization method. The polarization method is specified in JIS P8226: 2006, and the non-polarization method is specified in JIS P8226-2: 2011, both of which are known. The fiber measuring method by the optical automatic analysis method is preferably a fiber length measuring method by a non-polarizing method.

The calculation of the blending ratio of the raw material pulp based on the result of the fiber length measuring method can be performed by, for example, the following method, but is not limited thereto. First, an optical automatic analysis method is used for control softwood pulp (100% N material) and hardwood pulp (100% L material), and further, for a sample for which the mixing ratio of N material and L material is clarified as needed. The fiber length (fiber length distribution) and fiber width (fiber width distribution) are obtained by the fiber measurement method according to the above, and are used as control data. Next, the fiber length (fiber length distribution) and fiber width (fiber width distribution) of the test target are measured, compared with the control data, and the blending ratio of the raw material pulp of the test target is calculated by a preset statistical means. be able to.

The fiber length (fiber length distribution) can be measured based on the projection method (Lp), the center line method (Lc), or the like, and is preferably performed based on the center line method.

The measured fiber length can be, for example, the fiber length as defined below:
(1) Number average fiber length (L, mean length), which is a value obtained by dividing the total length of all measured fibers by the number of measured fibers.
(2) Length-weighted mean length (LI), which is an average value of fiber lengths weighted by length to reflect the influence of long fibers.
(3) Weighted average fiber length (Lw, mass-weighted mean), which is the average value of fiber lengths that are weighted by length and then multiplied by the length to more strongly reflect the influence of long fibers. length).

The fiber measuring method by the optical automatic analysis method may be a capillary method or a flow cell method.

The fiber length measurement method by the optical automatic analysis method can be performed using a commercially available device. The polarization method can be carried out using, for example, Kajaani FS200 manufactured by Metso Automation. The non-polarization method can be carried out using Kajaani Fiber Lab manufactured by Metso Automation, MorFi Compact manufactured by Techpap, FQA-360 manufactured by OPTEST, Fiber Plus manufactured by Lorenzen & Wettre, and FS5 manufactured by VALMET.

Thus, the blending ratio of the raw material pulp to be tested is calculated. According to the present invention, the blending ratio of the raw material pulp can be calculated with high accuracy. In a preferred embodiment of the invention, the variation count is 3% or less, more preferably 1% or less. The coefficient of variation can be calculated based on JIS P8226 or JIS P8226-2.

The method of the present invention can easily and accurately calculate the blending ratio of the raw material pulp to be tested. For example, it is useful as a quality control method in the paper manufacturing process. By a method for manufacturing a paper product including a step of performing quality control by such a quality control method, it is possible to manufacture a paper product whose quality is sufficiently controlled.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.

Creating a calibration curve [1]
(1) Creation of data NI for calibration curve
A slurry prepared by adjusting the bleached kraft pulp (NBKP) produced from chips of Pinus sylvestris material to a solid content concentration of 4.0% by mass was adjusted to a freeness of 540 ml CSF using a refiner to prepare sample N1.

The fiber composition of sample N1 was measured by JIS P8120: 1998, and it was confirmed that the N material ratio was 100%.

Sample N1 with water added to make the solid content concentration 0.003% by mass was measured for fiber length and fiber width using a non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap), and data NI for calibration curve was obtained. rice field. The flow cell method was used as the measuring method, and the measurement was performed under the device conditions that the average fiber length was 0 to 10 mm, the average fiber width was 3 to 75 μm, the number of measured fibers was 20,000 to 30,000, and the measurement time was 3 minutes.

(2) Preparation of calibration curve data NII
Instead of bleached kraft pulp made from Pinus sylvestris chips, bleached kraft pulp made from Lalix kaempferi chips was used, and the sample was adjusted to a freeness of 600 ml CSF in the same manner as sample N2. N2 was created.

The fiber composition of sample N2 was measured by JIS P8120: 1998, and it was confirmed that the N material ratio was 100%.

Sample N2 was measured using a non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap) to obtain data NII for a calibration curve.

(3) Creation of data LI for calibration curve
A slurry prepared by adjusting the bleached kraft pulp (LBKP) produced from Eucalyptus globulus chips to a solid content concentration of 4.5% by mass was adjusted to a freeness of 440 ml CSF using a refiner to prepare sample L1.

The fiber composition of sample L1 was measured by JIS P8120: 1998, and it was confirmed that the L material ratio was 100%.

The sample L1 was used for measurement in the same manner as the calibration curve data NI, and the calibration curve data LI was obtained.

(4) Preparation of calibration curve data LII
A sample L2 was prepared in the same manner as the sample L1 except that the bleached kraft pulp produced from the Eucalyptus pellita chip was used instead of the bleached kraft pulp produced from the Eucalyptus globulus chip.

The fiber composition of sample L2 was measured by JIS P8120: 1998, and it was confirmed that the L material ratio was 100%.

Sample L2 was measured using a non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap), and data LII for a calibration curve was obtained.

(5) Preparation of calibration curve NI-LI The N / L ratio is 100/0 and 0 using the calibration curve data NI and the calibration curve data LI by the non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap). A calibration curve NI-LI connecting with / 100 was created.

(6) Preparation of calibration curve NI-LII The N / L ratio is 100/0 and 0 using the calibration curve data NI and the calibration curve data LII by the non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap). A calibration curve NI-LII connecting with / 100 was prepared.

(7) Preparation of calibration curve NII-LI The N / L ratio is 100/0 and 0 using the calibration curve data NII and the calibration curve data LI by the non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap). A calibration curve NII-LI connecting with / 100 was prepared.

Table 1 shows the conditions for creating the above calibration curve.

Test Example 1 (Test of pulp composition of papermaking raw material)
Pulp slurry produced using Pinus sylvestris (NBKP) and Eucalyptus globulus (LBKP) at a mass ratio of NBKP / LBKP of 50/50 (the filter water content after refiner is NBKP 540 ml CSF, respectively. A papermaking raw material A in which a filler, a paper strength enhancer, and an internal sizing agent were added and mixed with LBKP 440 mlCSF) was collected.

JIS P8120: 1998 7. For papermaking raw material A, except that the boiling time was 120 minutes. The fiber type ratio (N / L ratio) was calculated from the calibration curve NI-LI using a non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap) for the papermaking raw material A dissociated in the above manner.

The fiber composition of the papermaking raw material A was confirmed by JIS P8120: 1998, and the standard deviation and the fluctuation count were obtained by comparing with the fiber type ratio measured above (Example 1).

The papermaking raw materials B to M shown in Tables 2 and 3 were also measured at the same time using the calibration curves shown in the table (Examples 2 to 9 and Comparative Examples 1 to 3 ).

The results are shown in Tables 2 and 3.

Test Example 2 (Test of paper pulp composition)
Using the above-mentioned papermaking raw material A, a high-quality paper A having a basis weight of 77.0 g / m2, a paper thickness of 100 μm, and an ash content of 8.0% was produced by a long net paper machine.

JIS P8120: 1998 7. Except for the fact that the wood-free paper A has a boiling time of 120 minutes. The fiber type ratio (N / L ratio) was calculated from the sample A dissociated in accordance with the calibration curve NI-LI using a non-polarized fiber length measuring device MorFi Compact (manufactured by Techpap) (Example 13).

High-quality paper B was similarly produced using the papermaking raw material B, and the fiber type ratio (N / L ratio) was calculated by the calibration curve NI-LII (Example 14).

The results are shown in Table 4.

Creating a calibration curve [2]
A calibration curve was prepared in the same manner as in the above-mentioned "Preparation of calibration curve [1]" except that the non-polarized fiber length measuring device Kajaani Fiber Lab (manufactured by Metso Automation) was used. The measurement method was a capillary method, and the average fiber length was 0.2 to 7.0 mm, the average fiber width was 10 to 75 μm, the number of measurements was 10,000 to 20,000, and the measurement time was 8 to 10 minutes.

Test Example 3 (Test of pulp composition of papermaking raw material)
The fiber type ratio (N / L ratio) was determined for the papermaking raw materials N to Q shown in Table 5 in the same manner as in Test Example 1 except that the non- polarized fiber length measuring device Kajaani Fiber Lab (manufactured by Metso Automation) was used. Calculated. The fiber composition of each papermaking raw material was confirmed by JIS P8120: 1998, and the standard deviation and the variation count were obtained by comparing with the fiber type ratio measured above (Examples 10 to 11 and Comparative Examples 4 to 5 ).

The results are shown in Table 5.

Claims (6)

Using 100% coniferous pulp and 100% perforated pulp based on the fiber length measurement method by an optical automatic analysis method, using coniferous pulp and broadleaf pulp that match the tree species and beating degree with the paper product or pulp to be tested , 2 A method for testing the fiber composition of a paper product or pulp, in which a calibration line is created from the point data and the ratio of the coniferous pulp to the broadleaf pulp in the test subject is calculated. Based on the fiber length measurement method by an optical automatic analysis method using the coniferous wood pulp and broadleaf wood pulp immediately after the beating step during the manufacturing process of the paper, paperboard, or pulp to be tested as a control, the coniferous tree pulp 100% and the broadleaf tree. A fiber composition test method for paper products or pulp, in which a calibration line is created from two points of 100% pulp and the ratio of coniferous pulp to broadleaf pulp in the paper, paperboard, or pulp to be tested is calculated. The method according to claim 1 or 2, wherein the ratio of the softwood pulp to the hardwood pulp in the test subject is calculated based on the fiber length measuring method by the non-polarization method. The method according to any one of claims 1 to 3, wherein the coefficient of variation is 3% or less. A quality control method in a paper manufacturing process, which comprises a step of calculating the ratio of softwood pulp to hardwood pulp in a test subject by the method according to any one of claims 1 to 4. A method for manufacturing a paper product, which comprises a step of performing quality control by the quality control method according to claim 5.