FI116534B - Method for controlling the fiber properties of fiber pulp - Google Patents

Description

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A method for adjusting the fiber properties of a pulp

The present invention relates to a method for adjusting the fiber properties of a pulp according to the preamble of claim 1. The invention also relates to a method for producing a pulp according to claim 18 and to a fiber product according to the preamble of claim 19.

Paper mills use a variety of wood raw materials to make paper, depending on the type of end products, such as paper or packaging products, that are produced from intermediates, such as pulp and / or mechanical or chemimechanical pulp. Generally, different grades of paper are made from both long fibers and short fibers. The long fiber raw material gives the paper strength, while the short fiber gives the paper smoothness and printing properties. For example, in the manufacture of long fiber pulp for fine paper, a raw material having an average fiber length (length weighted) of about 2 mm is used.

The average fiber length of the long fiber portion of the magazine paper raw material should preferably be greater than 2.2 mm. Preferably, the average fiber length of the long fiber pulp used for the production of high quality paper (or board) in printing and other properties should be 2.3 mm. Such a raw material is called reinforcing fiber and can advantageously be used, for example, for the production of high quality LWC (light weight coated) low-20 basis weight coated paper. Such paper has good printing properties but little use is made of the material. Thus, the strength of the paper comes from the reinforcing fiber »» * * · and the printing properties from mechanical pulp.

• * * i * 'i,' The current methods do not adjust the fiber length of the wood at all, or • · · 25 attempts to adjust the wood by entering the log diameter or logging method when entering the mill.

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! .. * basis. The average fiber length of wood is obtained by mixing raw materials of different fiber lengths in appropriate proportions. Because given by the thinning tree:. ·, The fiber length is shorter than the pre-thinning compound obtained from older wood. · · ·, With older wood and possibly top wood. However, the problem is that * ·. *, 30 the more woody raw material a young tree needs to be used, the shorter !, I fiber will be obtained. In order to produce the desired fiber length for paper manufacturers, the sawdust has to be blended with the raw material to increase the average fiber lengths. Nevertheless, it is difficult to maintain the fiber length of the wood raw material at the desired level.

2 116534 In the present invention, it has been found that the fiber length of the wood raw material obtained from different parts of the wood is different. Previously, the fiber properties of wood have been considered only on a tree or tree basis, not on a tree section, and the fact that the wood raw material obtained at the base of the wood 5 is different in fiber length and fiber dimension than the wood top. Based on these findings, a surprising invention has been made that the amount of annual wood chips affects the wood fiber length and fiber length uniformity.

According to the present invention, the fiber properties of a pulp, such as pulp or paper pulp, can be adjusted by using a wood raw material selected on the basis of the amount of annual wood chips in the manufacture of pulp or (Kemi) mechanical pulp.

More specifically, the solution according to the invention is essentially characterized by what was stated in the characterizing part of claim 1.

The amount of annual wood chips correlates with wood fiber dimensions such as fiber length and fiber length. By dividing the wood raw material into classes on the basis of the number of annual beds, a wood raw material of uniform fiber dimensions is obtained. If classes are appropriately selected, there is also little variation in dimensions within the class. Determining the Number of Yearbooks * «* · • ·. can be mechanized and made at any stage into wood moth and pulp cooking. ' "In between, in the case of chemical pulping or the number of annual pads« · · '' can be determined at any stage of the timber moth and grinding or grinding! ' '. ((C) TMP refiner) for mechanical or (Kemi) mechanical pulp.

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The wood raw material can be divided into classes according to the number of annual pads. Then. . : By selecting a material from a particular category, it is possible to obtain a fiber with dimensions * ·. · · *. are at the desired level. On the other hand, by combining and blending the different types of wood raw material, a fiber having the desired, pre-selected fiber shapes can be obtained. Depending on the type of wood involved, the distribution of the annual chip classes may need to be done to obtain • preselected fiber dimensions.

The invention provides considerable advantages. Thus, the process described can improve the quality of the wood raw material and obtain wood raw material of uniform quality with different fiber dimensions. Also economically, the method is advantageous because the fiber properties can be influenced from the time of the felling of the wood and not after the measurement of the fiber properties.

5 The invention will now be explained in more detail by means of a detailed description and a few embodiments.

Figure 1 shows the correspondence between the annual battles and fiber lengths and fiber length (with standard deviation) of spruce logs obtained by regeneration search when the material is sorted into annual chaff categories. Figure 3 shows the correspondence between the length and fiber length (standard length deviation) of the sorted spruce base logs and the fiber length (standard length deviation) sorted by the regeneration search Figure 4 shows the spruce rootstock and fiber length sorted by the diameter / diameter . Figure 5 illustrates the relationship between spruce laths sorted on the basis of log age / annual bedding and fiber length and fiber length (with standard deviation)

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· '! equivalence, · · 'in Figure 6 is shown in thinning search sorted by diameter / diameter. ·. : correspondence between spruce tops and fiber length and fiber length (standard length> ». · · ·. 25 deviations) in Fig. 7 is shown for thinned spruce, sorted by annual grit. : equivalence between the bottom sleepers and the fiber length and fiber length (with standard deviation). [. Figure 8 shows the correspondence between thinned logs sorted by diameter / diameter, thinned 30, in fiber thinning, and fiber length and fiber length (standard length, t); ; Figure 9 shows a pine tree sorted by annual bark in the regeneration search

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correspondence between tops and fiber length and fiber length (with standard deviation) . Fiber pulp having a predetermined fiber dimension can be used in the manufacture of paper, board or packaging materials or in any other process utilizing the pulp.

10 According to the present method, the wood raw material is sorted according to the number of logs on the log. Annual woodcarvings are formed as the wood grows periodically and can be distinguished from one another. For example, Finnish conifers have a light 'spring wood ring' of thin cavity cells / fibers and a 'summer wood ring' of small cavity thick wall cells / fibers in turn in the cross-section of the tree.

15 By calculating the number of these concentric junctions, the age of the log in this example year is obtained. Periodicity, in turn, is due to variations in environmental conditions such as light, heat and water supply. Seasonal fluctuations between warm summer and cold winter cause the formation of annual groves, as well as dry summer and rainy winter.

. . 20 »t» ·. Sorting the tree "by log" means that for every tree to be harvested, "the tree, the truncated parts of which are called logs, is determined by the number of annual chips. This is most preferably done mechanically or by modeling. at any stage of wood processing during pulp production (after wood, · · · * 25 before cooking) or during mechanical or chemimechanical pulp (after felling, before grinding or before grinding). After that, the logs are sorted into their own heaps based on the number of annual chips. It is advantageous if the annual chips are already determined by a harvester in the forest when felling a tree. read vi The wood raw material can then be sorted by the number of annual chips; ': Tea as soon as the tree is felled, which reduces the need to sort the logs later.

'* Preferably, sorting can be done at the factory by counting the number of annual chips or by 5116534 sorting according to the number of chips or modeling on the feller.

The process of the present invention can be applied to the production of pulp or paper pulp 5 using wood as a raw material having a periodic growth pattern. This type of growth is for trees with rapid and slow growth stages due to variations in heat, light and / or water supply as described above.

The wood raw material may be softwood or hardwood. Conifers include, for example, fir and 10 pines. Deciduous trees include birch, aspen, hybrid aspen, poplar, beech, red beech, hornbeam, oak, alder, maple, acacia and eucalyptus.

For example, the fiber dimension property refers to fiber length and fiber length mass. Fiber length refers to the arithmetic mean of the fiber length distribution, the fiber length weighted average or weight weighted average. Of these, the length-weighted average is generally used to best describe the paper's technical potential.

Fiber length pulp refers to the weight of a fiber string in a pulp or pulp, e.g. . 20 Ionometer weight in milligrams. The former can be measured specifically for this purpose. devices such as the FS-200 and Fibrelab. Equipment. '! are based on the measurement of fiber dimensions by optical measurement techniques in suitable media flowing in cuvettes. The results obtained with the devices are device specific and not absolutely accurate. Good laboratories have developed internal standards for measurements, · ·. 25 and calibrations.

. ·. A: The present invention has surprisingly found that for certain desired fiber lengths. * '*. and dimensions and surprising smoothness are achieved when the raw material is sorted by year .. '. based on the number of cartridges in different classes. The number of classes can range from 2 to 60, '·. Preferably, there are 2-6 classes, typically 3-4.

; ; According to a preferred embodiment, sorting can be carried out, for example, into the following classes: less than 20 annuals, 21-30 annuals, 31-40 annuals, over 40 annuals.

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For example, if the wood raw material is divided into the following categories: less than 20 annual, 21-30 annual, 31-40 annual, more than 40 annual, the following equivalences will be obtained:

The number of annual carts is fiber length 5 less than 20 2 21-30 2.3 31-40 2.4 more than 40 2.5 10 According to another preferred embodiment, the annual carts are sorted into classes: less than 10 annual, less than 20 annual, less than 30 annual, less than 40 annual, less than 50 annual, more than 50 annual.

By sorting the raw material by log or group of logs according to the number of annual pads into 15 different classes, the desired fiber dimension property, e.g. fiber length, is obtained by selecting the wood raw material separately from a particular class or by combining

By the present process, mechanical, chemical or chemimechanical pulp can be made from the selected raw material.

, ''; For example, if a softwood product having a fiber length (length weighted '.'I. * Average) of less than 2.0 mm is desired, it is typically necessary to select a wood raw material with an annual log!'. of 25 softwoods with a fiber length of 2.0..2.3 are selected from a wood raw material with a number of logs at the base of the log of 21-30 annuals. ..2.5, select a wood raw material with the number of logs on the log. · · ·, With a log at the base of 31 to 40 annual and to obtain a fiber length between 2.5..3.5, select a wood raw material with the number of logs at the base of the log is over 40 annuals.

30 In the example, the measurement is made at the base, but alternatively the measurement can be made at the top end of the log '^' and alter the annual bed, for example, by a model to match the annual bed bed as a function of the length of the bed.

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In order to obtain the preselected fiber dimensions, annual tree species may need to be subdivided into different tree species. For example, in birch the fiber lengths range from about 0.7 mm to 1.2 mm and the annual grading classes must be chosen so as to give the desired fiber lengths within this range.

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The method of producing a pulp of the invention having preselected fiber dimensioning properties typically comprises the following process steps: - selecting wood as a wood raw material having a periodic growth pattern, - sorting the wood raw material by log or by group of logs into fiber dimension, for example fiber length and / or length mass, - the raw material is selected separately from a particular class, or some or all of the different categories of materials are combined to achieve a pre-selected fiber length, or 15 - made from mechanical, chemical or chemical .

Sorting may be carried out on different coniferous or deciduous trees based on the annual classes of the log or group of logs and may achieve quality improvement in the adjustment of the fiber dimensions and / or the tolerance of the pulp, mechanical pulp or chemimechanical pulp, and. 20 uses it to improve the quality of their products.

, '' The following non-limiting examples illustrate the invention: I '. A total of 442 samples were taken from the total amount of spruce trees (regeneration and thinning) coming to the factory. The tree tops and root sections were sorted separately and their percentage determined. According to the results, the volume of the tops of the regeneration felling (and, ·.: Also with this precision) was 54% by weight and 15% by base,

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. · · ·. the tops accounted for 17% of the tops and the base parts for 14% of the total spruce sum coming to the mill. This material was measured and sorted based on the thickness of the log and / or the number of annual beds.

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Example 1

The trees felled in connection with the spruce regeneration felling were sorted according to the number of annual deciduous trees into categories <20 annual deciduous trees, 21-30 annual deciduous trees, 31-40 annual deciduous trees and> 40 annual deciduous trees. The results are shown in Figure 1.

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The proportion of wood in the class <20 annual bark was 12%, the fiber length ranged from 1.98 to 2.16 (standard dev.) Weighted average fiber length was 2.07 mm. The fiber length in this class ranged from 0.149 to 0.160 mg / m (st. Dev.).

The proportion of wood in the category 21-30 annual bark was 38%, the fiber length ranged from 2.20 to 2.38 (st.dev.), The average fiber length was 2.29 mm. The fiber mass in this class ranged from 0.163 to 0.172 (st.dev.) Mg / m.

The proportion of wood in the 31-40 year-old bark was 25%, the fiber length ranged from 15 to 2.36 mm (st.dev.), The average fiber length was 2.42 mm. The fiber mass in this class ranged from 0.171 to 0.178 mg / m (st.dev.)

The proportion of wood in the category> 40 annual groves was 25%, the fiber length ranged from 2.46 mm to 2.59 mm (st.dev.), And the average fiber length was 2.52 mm. Fiber length in this class,. 20 ranged from 0.184 to 0.178 mg / mm (st.dev.).

Example 2 '· ..' The tops of felled trees in connection with spruce regeneration felling were sorted by diameter '- 25 into <80 mm, <100 mm, <120 mm, <140 mm, <160 mm,> 160 mm.

When measuring the fiber length and fiber length of the classes, it was found that the fiber length and fiber length masses overlap or partially overlap, as can be seen in Figure 2.

; ': For example, in the <80 mm and <140 mm classes, the fiber lengths overlap completely and; diameter sorting is therefore of little practical importance.

: 30: ': Example 3'; '; In the context of the spruce regeneration felling, the felled trees were sorted according to the number of annual deciduous trees at the base logs into classes <30 annual, <40 annual and> 40 35 annual. The results are shown in Figure 3.

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The proportion of wood in the class <30 annual bark was 10%, the fiber length ranged from 2.21 to 2.44 nun (calculated st.dev.), The length weighted average fiber length was 2.32 mm. The fiber mass in this class ranged from 0.163 to 0.175 mg / m (st.dev.).

The proportion of wood in the <40 annual groves was 21%, the fiber length ranged from 2.40 to 2.56 mm, the average fiber length was 2.48 mm. The fiber mass in this class ranged from 0.173 to 0.182 mg / m (st.dev.).

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The proportion of wood in the category> 40 annuals was 69%, the fiber length ranged from 2.46 mm to 2.68 mm, and the average fiber length was 2.57 mm. The fiber mass in this class ranged from 0.188 to 0.176 mg / m (st.dev.).

15 Example 4

During the felling of spruce trees, felled trees were sorted by logs according to diameter into classes <100 mm, <120 mm, and> 120 mm. When the fiber length and fiber length classes were measured and calculated, it was found that the fiber length and fiber length masses (st.dev.) Overlap, as can be seen in Figure 4.

Example 5: The tree trunks felled in connection with thinning of spruce trees were sorted by age or: 25 annual deciduous trees into categories <20 annual deciduous trees, 21-30 annual deciduous trees, 31-40 annual deciduous trees and> 40 annual deciduous trees. The results are shown in Figure 5.

t:: The proportion of wood in the <20 annual grit was 20%, the fiber length varied between: 1.99 - 2.19 mm (st.dev.), the length weighted average fiber length was 2.09 mm.

; : The fiber mass in this class ranged from 0.150 to 0.162 mg / m (st.dev.).

, *. The proportion of wood in the category of 21-30 annuals was 47%, the fiber length varied between .. | 2.23 to 2.46 mm (st.dev.), Length weighted average fiber length was 2.35 mm.

The fiber mass in this class ranged from 0.164 to 0.177 mg / m (st.dev.).

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The proportion of wood in the 31-40 year-old groves was 21%, the fiber length ranged from 2.36 to 2.50 mm (st.dev.), And the length-weighted average fiber length was 2.43 mm. The fiber mass in this class ranged from 0.172 to 0.179 mg / m (stdev).

The proportion of wood in the category> 40 annual wood chips was 21%, the fiber length ranged from 2.43 to 2.60 mm (stdev), the length weighted average fiber length was 2.51 mm. The fiber mass in this class ranged from 0.174 to 0.185 mg / mm (stdev.).

Example 6

In the case of spruce thinning, the felled tree trunks were sorted by diameter into <100 mm, <140 mm, <120 mm, <160 mm, and> 160 mm. When the fiber length and fiber length mass of the classes were measured, it was found that the fiber length and fiber length masses (st.dev.) Overlap or partially overlap, as can be seen in Figure 6.

Example 7 20 The base parts of trees felled in connection with thinning of spruce trees were sorted: ..: by logs, according to the number of annual deciduous trees to classes <20 annual deciduous trees, 21-30. . ·. annual, 31-40, and> 40 annual. The results are shown in Figure 7.

* »: '; The proportion of wood in the <20 annual groves was 4%, the fiber length ranged from 1.97: * *. * 25 -2.16 mm (st.dev.), Length weighted fiber length averaged 2.06 mm.

; ' '': The fiber mass in this class ranged from 0.149 to 0.160 mg / m (st.dev.).

•: The proportion of wood in the <30 annual groves was 27%, the fiber length ranged from »· · 2.28 to 2.46 mm (st.dev.), The length weighted average fiber length was 2.37 mm.

; v. 30 The fiber mass in this class ranged from 0.167 to 0.176 mg / m (st.dev.).

: The proportion of wood in the <40 annual groves was 33%, with varying fiber lengths. ·. : 2.45 to 2.57 mm (st.dev.), Length weighted average fiber length was 2.51 mm.

· ·

The fiber mass in this class ranged from 0.176 to 0.183 mg / m (st.dev.).

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The proportion of wood in the category> 40 annuals was 21%, the fiber length ranged from 2.55 to 2.64 mm (st.dev.), The length weighted average fiber length was 2.60 mm. The fiber mass in this class ranged from 0.182 to 0.188 mg / m (stdev.).

Example 8

The logs felled in connection with thinning of fir trees were sorted by diameter into <100 mm, <120 mm and> 120 mm. The fiber length and fiber length masses of the Kim classes were measured, and it was found that the fiber length and fiber length masses (stdev.) Overlap partially or completely as can be seen in Figure 8.

Example 9 15 In the context of felling of pine trees, the tops of felled trees were sorted according to the number of annual deciduous trees into classes <20 annual, 21-30 annual, 31-40 annual, 41-50 annual and> 50 annual. The results are shown in Figure 9.

The proportion of wood belonging to the <20 annual grit was 2%, the fiber length ranged from 1.57 to 1.79 mm (stdev.), The length weighted average fiber length was 1.68 mm.

: · · | The fiber mass in this class ranged from 0.197 to 0.206 mg / m (stdev).

; ': The proportion of wood in the 21 to 30 year old bark was 13%, the fiber length ranged from "': 1.85 to 2.07 mm (stdev.), The length weighted average fiber length was 1.96 mm.

•. The fiber mass in this class ranged from 0.207 to 0.214 mg / m (st.dev.).

The proportion of 31-40 year-old wood bark was 14%, the fiber length varied between '· · 1.99 - 2.16 mm (st.dev.), The length weighted average fiber length was 2.08 mm.

,., · The fiber length in this class ranged from 0.212 to 0.216 mg / m (stdev.).

: V 30: ': The proportion of wood in the category 41-50 annuals was 24%, with varying fiber lengths. . : 2.12 to 2.22 mm (st.dev.), Length weighted average fiber length was 2.17 mm.

. . : The fiber mass in this class ranged from 0.215 to 0.218 mg / m (stdev.).

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The proportion of wood in the category> 50 annuals was 47%, the fiber length ranged from 2.19 to 2.28 mm (st.dev.), And the length weighted average fiber length was 2.24 mm. The fiber mass in this class ranged from 0.217 to 0.221 mg / m (st.dev.).

Example 10 In the context of pine regeneration felling, the tops of felled trees were sorted by diameter into <100 mm, <120 mm, <140 mm, <160 mm, and> 160 mm. The fiber lengths and fiber lengths of the Kim classes were measured, and it was found that the fiber lengths and 10 fiber lengths (st.dev.) Overlap partially or completely as can be seen in Figure 10.

Claims (18)

1. A method for controlling fiber properties of fiber pulp to a predetermined level, characterized by the fact that a fiber pulp is used, which is sorted stock or stock group based on the number of ring rings in classes representing a certain fiber dimension property. 2. A method according to claim 1, characterized in that the wood fox is sorted in connection with the wood felling or in the factory or in any part of the chain between the stump 10 and the cooking, the stump and the grinding or a (C) TMP pulverizer. Method according to claim 1 or 2, characterized in that the wood fox is sorted by machine. 15 Method according to some of the preceding claims, characterized in that the tree fox originates from trees with a periodic growth method. 5. A method according to any of the preceding claims, characterized in that the wood fox is made of coniferous wood. . 20 *. 6. A method according to any of the preceding claims, characterized in that • the wood fox is made of hardwood. : i Method according to any of the preceding claims, characterized in that: by fiber-dimension property is meant fiber length or fiber length mass. :,; 8. A method according to any of the preceding claims, characterized in that, the wooden fox is sorted on the basis of the number of rings in different classes, the number of which is up to 2 - 60, preferably 2-6. 30 * 1 I Method according to any one of the preceding claims, characterized by. \: that the wooden fox is sorted log or log group on the basis of the number of rings. in the following classes: under 20 rings, 21-30 rings, 31-40 rings, over 40 rings. 116534 10. A method according to any of the preceding claims, characterized in that the wooden fox is sorted log or log group on the basis of the number of ring rings, e.g. in the following classes: under 10 rings, under 20 rings, under 30 rings, under 40 rings, under 50 rings, over 50 rings. 5 Method according to any of the preceding claims, characterized in that the wooden fox is sorted logically or logically on the basis of the number of rings in different classes and the desired fiber dimension property, such as the fiber length, is obtained by selecting the wood fox separately from a certain class or by complete or partially assemble 10 wooden products from different classes. Process according to any of the preceding claims, characterized in that mechanical, chemical or chemical mechanical pulp is produced by the process. 15 13. A method according to any of the preceding claims, characterized in that in the matter of coniferous wood to obtain a fiber length (with a weighted average length) below 2.0 mm, a wood raw material is selected, the number of log rings at the root end of the log is less than 20 rings. . ,: 20 Process according to any of the preceding claims, characterized by •. of asking for coniferous wood to obtain a fiber length (length weighted average) i '. In the interval 2.0 .. 2.3 a wood raw material is selected, the number of log rings at the root end of the log is up to 21-30 rings. 25 15. A method according to any of the preceding claims, characterized in that in the matter of coniferous wood in order to obtain a fiber length (length weighted average) in the range of 2.3 .. 2.5 a wood raw material is selected, the number of log rings at the root end of the log. up to 31-40 honor rings. : “'; 30 Method according to any of the preceding claims, characterized in, t ',; by asking about coniferous wood to obtain a fiber length (length weighted average) in, ·,: the interval 2.5 .. 3.5, a wood raw material is selected, the number of log rings at the root end of the log settles to over 40 rings. 116534 17. A method for producing fiber pulp with predetermined fiber dimension properties, characterized by the use of trees as a periodic growth method, - on the basis of the number of tree rings, the wood pulp is sorted into five classes representing a certain fiber dimension property, such as fiber length and / or fiber length. - the wood fox is selected separately from a certain class or by partially or completely merging different grade foxes in such a way that a predetermined fiber length and / or fiber length mass is obtained, and 10. mechanical, chemical or chemical mechanical pulp is produced from the wood fox. 18. A method for producing a fiber product having predetermined fiber dimension properties, characterized in that from the wood fox are determined stock or stock group by ring groups which give predetermined fiber dimension properties, - the wood fox is selected from a ring ring class, from the wood fox, and a fiber product is produced from the pulp. 20 »> • • • • • • • * * • · # * * · f * *» «* · • t * ·» Iitit