JP6669530B2 - How to make paper towels - Google Patents

Description

  The present invention relates to a method for manufacturing a paper towel. In particular, the present invention relates to a method for producing a one-ply paper towel using waste paper pulp as a raw material.

  There are two types of paper towels, one ply, also called single, and two ply, also called double.

  Single paper towels need to be one thicker than double paper towels, so each one tends to have a higher rice tsubo, a higher stiffness, and a higher hardness, and many feel tough to the touch .

  In addition, some paper towels contain recycled pulp as a raw material pulp or those made from 100% recycled paper pulp. Paper towels containing such recycled pulp tend to have a harder touch than those of 100% virgin pulp. It is in.

  On the other hand, since paper towels are mainly used for hand wiping after hand washing, they are required to have a high water absorption rate so that moisture attached to hands can be quickly absorbed.

  The water absorption speed of the paper towel can be increased by increasing the basis weight or the bulk, but when the paper towel is made high, the paper becomes harder and softer.

  On the other hand, in order to increase the softness of paper, a softener is added to pulp slurry, which is a raw material for papermaking. However, when a softener is added to the pulp slurry, it becomes softer and the water absorption rate is slightly improved, but it is not sufficient. If the amount of the softener is increased to increase the water absorption rate, it becomes difficult to maintain the strength required for hand wiping.

  As described above, it is difficult to improve both the softness, the water absorption rate, and the sufficient strength of the paper towel. Particularly, in the case of a single paper towel having a high stiffness and a tendency to harden, and the paper towel containing the waste paper pulp, the softness and the water absorption rate are sufficiently high. It is very difficult to improve both strength and strength.

JP 2013-36124 A Patent No. 5586903 Patent No. 5769986 JP 2013-108197 A

  Therefore, a main object of the present invention is to improve the softness, the water absorption rate, and the sufficient strength in a one-ply paper towel made from pulp containing waste paper, and in particular, the softness, the water absorption rate, and the sufficient strength. It is an object of the present invention to provide a method for producing a paper towel, which improves the paper towel quality.

The means for solving the above problems are as follows.
[Invention of claim 1]
A method for producing a one-ply paper towel using pulp containing waste paper pulp as a raw material pulp,
In the former part of the wire part, 20 to 40% by mass of a nonionic interface with respect to wet paper having a moisture content of 80% or more and a basis weight of 20 to 50 g / m ² after drying on the felt or wire immediately after passing through the couch roll. Adding a surfactant solution by 1 to 7 kg per ton of raw pulp by shower or spray, a surfactant addition step,
A press part for dewatering the wet paper to which the nonionic surfactant solution has been added,
A crepe processing step of imparting wet crepe,
A method for producing a paper towel, comprising: a dryer part for drying wet crepe processed wet paper.

[Invention of claim 2]
The method for producing a paper towel according to claim 1, wherein the nonionic surfactant solution is added such that the spraying direction of the shower or the spray and the conveying direction of the wet paper are at an angle of 50 degrees or less.

[Invention of claim 3]
The method for producing a paper towel according to claim 1 or 2, wherein the nonionic surfactant is added to the wet paper web from above the scattering prevention cover covering the cooch roll.

[Invention of claim 4]
The method for producing a paper towel according to any one of claims 1 to 3, wherein the slurry concentration of the papermaking raw material is 0.10 to 0.20% by mass.

[Invention according to claim 5]
The method for producing a paper towel according to any one of claims 1 to 4, wherein the creping rate in the creping step is 5 to 15%.

  According to the present invention described above, there is provided a method for producing a paper towel in which the softness, the water absorption rate, and the sufficient strength of a one-ply paper towel made of pulp containing waste paper are improved.

It is a figure for explaining the example of manufacture of the paper towel concerning the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the paper towel manufactured by the manufacturing method according to the present invention is a one-ply paper towel containing waste paper pulp. The basis weight of such paper towel is in the range of usually 20 to 50 g / m ^2, and many in the range of 30~45g / m ^2. The paper thickness of such a paper towel is usually in the range of 140 to 280 μm, and most of them are in the range of 150 to 200 μm.

Therefore, the method for producing a paper towel according to the present invention is a method for producing a single ply paper towel with a basis weight of 20 to 50 g / m ² and a paper thickness of 140 to 280 μm containing waste paper pulp. The softness and the water absorption rate of the paper towel are improved, and the sufficient strength is also exhibited.

  The required strength of the paper towels is, as a rule, the dry tensile strength in the vertical direction is 1500 to 2500 cN, the dry tensile strength in the horizontal direction is 900 to 1700 cN, the wet tensile strength in the vertical direction is 500 to 1000 cN, and the wet tensile strength in the horizontal direction. Is 250 to 600 cN.

  The method for producing a paper towel according to the present invention is a paper towel containing waste paper pulp as described above, and waste paper pulp is used as the raw material pulp. In the production method of the present invention, in particular, when the ratio of waste paper pulp in the raw pulp is 80% by mass or more, particularly when the raw material pulp is 100% by mass of the waste paper pulp, that is, in a paper towel highly blended with such waste paper pulp, Softness and water absorption rate are improved.

  Therefore, the raw material pulp used in the method for producing a paper towel according to the present invention is one containing 80% by mass or more of waste paper pulp, particularly 100% by mass of waste paper pulp. Hardwood kraft pulp (LBKP) and softwood kraft pulp (NBKP) are suitably used as raw material pulp other than waste paper pulp. These may be used as a mixture of both. The used paper pulp according to the present invention may be a known used paper pulp used for paper towels. For example, high quality waste paper pulp derived from deinked and bleached high quality paper and coated paper.

  The papermaking raw material in the method for producing a paper towel according to the present invention is obtained by converting the above raw pulp into a pulp slurry. The method of slurrying is not particularly limited, but may be a known method.

  Known additives can be used in the papermaking raw material according to the method for producing a paper towel according to the present invention. In particular, in the method for producing a paper towel according to the present invention, a dry paper strengthening agent and a wet paper strengthening agent can be added as an internal additive to the papermaking raw material so as to be in the range of the above-mentioned dry tensile strength and wet tensile strength. . Known dry strength agents and wet strength agents can be used. The amount of addition is 5 to 30 kg per ton of raw pulp in the case of dry strength agent and 10 to 40 kg in the case of wet strength agent.

  In the paper towel manufacturing method according to the present invention, the slurry concentration of the papermaking raw material is particularly preferably 0.10 to 0.20% by mass. The freeness (CSF) of the papermaking raw material is desirably 400 ± 150 cc. The effect of the present invention, especially the effect relating to the addition of the nonionic surfactant solution and its position, is exhibited by making paper using such a papermaking raw material.

  On the other hand, the papermaking equipment used in the method for producing a paper towel according to the present invention has a wire part, a press part, and a dryer part, and may be any of a round net system and a long net system. Strict boundaries between the wire part, the press part, and the dryer part differ depending on the papermaking equipment. In the present invention, the step of forming and stabilizing the wet paper is a wire part, and the step of dehydrating the wet paper and reducing the moisture content to a level sufficient to transfer the wet paper to the dryer part is performed by drying the wet paper with a press part and a dryer. The process of making paper is called the dryer part.

  The production method according to the present invention is particularly effective in a round-mesh papermaking facility, since the water absorption rate is remarkably improved particularly in a round-mesh system in which the distance between the press parts is short. Also, the format of the former is not limited. Hereinafter, description will be further made with reference to FIG. FIG. 1 shows a round net papermaking facility X1.

In the method for manufacturing a paper towel according to the present invention, in the former part 1 of the wire part P1, the moisture content on the felt 13 or the wire (also referred to as a bulky wire) immediately after passing through the couched roll 11 is 80% or more and the basis weight after drying. A surfactant in which 20 to 40% by mass of a nonionic surfactant solution 30 is added to a wet paper W1 having an amount of 20 to 50 g / m ² by a shower or a spray, in an amount of 1 to 7 kg per ton of raw pulp. It has an addition step.

  Here, the coach roll 11 according to the present invention is one in which the wet paper is formed on the felt 13 or the wire from the papermaking raw material together with the head box, the former 14 and the inlet in the former section 1. In addition, the papermaking equipment X1 according to the method for manufacturing a paper towel of the present invention is not limited to equipment that transports wet paper with only one of wire and felt. A facility in which the step of transporting the wet paper by wire and the step of transporting the wet paper by felt may be mixed.

In the method for producing a paper towel according to the present invention, in order to make the moisture content of the wet paper W1 on the felt 13 or the wire immediately after passing through the coach roll 11 equal to or more than 80%, the above-mentioned paper concentration raw material having a slurry concentration and freeness is used, and the coach roll is appropriately used. This can be satisfactorily achieved by appropriately suctioning the wet paper W1 at 11 to form the wet paper W1. Further, in order for the basis weight after drying in the wet paper W1 to be ²⁰ to 50 g / m ² , the discharge of the papermaking raw material from the former 14 may be adjusted. Adjustments can of course be made.

  On the other hand, when the concentration of the nonionic surfactant solution 30 is less than 20% by mass, the water absorption rate and the softness do not sufficiently increase. Also, when the amount of the nonionic surfactant solution added is less than 1 kg per tonne of raw pulp, the water absorption rate is not sufficiently increased. Conversely, if the concentration of the nonionic surfactant solution exceeds 40% by mass or the amount of addition exceeds 7 kg per ton of the raw pulp, the paper strength is excessively reduced and the paper is easily broken. As the nonionic surfactant solution according to the present invention, polyoxyalkylene alkyl ether is particularly suitable. The nonionic surfactant solution is desirably an aqueous solution using water as a solvent in view of affinity with the wet paper web W1. In addition, an additive or the like for improving the stability of the solution can be added to the solution within a range that does not affect the nonionic surfactant solution.

  Here, in the method for producing a paper towel according to the present invention, the position where the nonionic surfactant solution 30 is added is particularly important. When internally added to the papermaking raw material, the yield of the nonionic surfactant solution is extremely poor, the adhesion to the pulp fiber is not sufficient, and the water absorption rate and softness are not sufficiently improved. On the other hand, when the nonionic surfactant solution is added in the press part P2 subsequent to the wire part P1, since the moisture content of the wet paper is reduced, the penetration of the nonionic surfactant solution into the wet paper is slow, and the water absorption rate and the softness are increased. In some cases, the improvement in the dryness may not be exhibited, and the moisture content of the wet paper may increase again at a position close to the dryer 60. More likely to occur.

In the method for manufacturing a paper towel according to the present invention, the nonionic surfactant solution is added to the wet paper web W1 having an extremely high moisture content immediately after passing through the couch roll 11 by showering or spraying, so that the subsequent web part P1 is in a subsequent stage. The contact time between the pulp fiber in the wet paper and the water containing the nonionic surfactant solution is sufficiently ensured before the gentle water pressing and the water pressing in the press part P2 are performed. In the process of squeezing the moisture in the wet paper through the felt 13 or the wire, the non-ionic system is directly supplied from the surface of the wet paper W2 that is not in contact with the felt or the wire, that is, the shower device 15 or the spray device for showering or spraying. Nonionic interface from the surface where the surfactant solution is applied to the surface in contact with the felt or wire The nonionic surfactant solution is uniformly diffused to the inside of the wet paper web as the water containing the surfactant solution moves and the water is squeezed while moving, and the drying in the dryer part P3 is effectively performed. Become so. As described above, in the paper towel manufacturing method according to the present invention, the nonionic surfactant solution is added to the high moisture content wet paper W1 immediately after the couch roll 11 by showering or spraying, so that the nonionic surfactant is added. The effect of the solution is exhibited. Then, especially after drying basis weight relative to the water content of 80 mass% or more of the wet paper comprising fibers amount to be 20 to 50 g / m ^2, 20 to 40 wt% concentration of the nonionic surfactant solution, the amount Is set to 1 to 7 kg / pulpton, the effect is more reliably exhibited.

  Here, the shower device 15 or the spray device for adding the nonionic surfactant solution to the wet paper web W1 is not particularly limited. A nozzle type, a rotor damping type, a rotary spray type spray device, and the like can be used. However, in the method for producing a paper towel according to the present invention, the fiber orientation and the formation in the wet paper are not affected by taking into account that the paper towel is added by external addition to the wet paper having a high moisture content immediately after passing through the couched roll 11. The ejection pressure and the size of the droplet are appropriately adjusted.

  Further, in the method for producing a paper towel according to the present invention, when applying the nonionic surfactant solution to the wet paper web W1 by shower or spray, the spray direction of the shower or spray from the shower device or spray device, It is desirable that an angle (indicated by α in the drawing) with respect to the transport direction of the wet paper W1 be 50 degrees or less. With such an angle, when the nonionic surfactant solution 30 is applied to the wet paper web W1, it is difficult to affect the fiber orientation in the wet paper web. Furthermore, the coach roll 11 in the papermaking facility is a portion where the papermaking raw material having a high moisture content contacts via a wire or the like, and is provided with a scattering prevention cover 40 so as to prevent the papermaking raw material from scattering. For this reason, when the angle α is provided between the shower or spray jet direction and the transport direction of the wet paper web W1 as described above, the jet port of the shower device 15 or the spray device is positioned above the scattering prevention cover 40. Thus, it is desirable to add the nonionic surfactant to the wet paper web W1 from above the scattering prevention cover 40 covering the coach roll 11. In this case, even if the nonionic surfactant solution drops dropping from the shower device 15 or the spray device downward, the droplets fall onto the scattering prevention cover 40. This phenomenon causes the formation of the wet paper W1. Is prevented from affecting.

In the method for producing a paper towel according to the present invention, it is desirable to use a fan-shaped nozzle as the nozzle of the shower device or the spray device. The water pressure is preferably 1.5 to 10 kg / cm ² , and is preferably added to a wet paper web flowing at a speed of 200 to 2,000 m / min.

  The wet paper web W1 to which the nonionic surfactant solution has been added in the former part 1 of the wire part P1 in this way is transported to the subsequent stage of the wire part by the felt 13 or the wire, and further transported to the press part P2.

  In the method of manufacturing a paper towel according to the present invention, the subsequent steps of the wire part P1 and the press part P2 can be performed in the same manner as the known method of manufacturing a paper towel. In the press part P2, the moisture of the wet paper web W2 is squeezed by the suction action of the suction roll or suction box (not shown) located on the opposite side of the felt 13 or the wire from the wet paper web mounting surface, or by the press roll 54. A plurality of suction rolls, suction boxes and press rolls 54 can be provided. The suction force of the suction roll and the suction box and the press pressure by the press roll 54 are adjusted by a known method in consideration of physical properties such as the thickness of the paper towel to be manufactured.

  The method for producing a paper towel according to the present invention includes a creping step 2 of applying wet crepe to the wet paper W2 dehydrated in the press part P2 and having a reduced moisture content. The moisture content of the wet paper W2 at the time of applying the wet crepe is desirably 40 to 60%. That is, the moisture content of the wet paper web W2 is reduced to 40 to 60% in the press part P2, and is transferred to the dryer 60. The crepe rate here is desirably 5 to 15%. By imparting wet crepe and setting the crepe ratio to 5 to 15%, it becomes easier to achieve improvement in water absorption speed and softness and sufficient strength. In particular, it exerts a favorable effect on the improvement of the water absorption rate due to the development of strength and bulkiness in a wet state. The crepe rate is calculated from the difference in the transport speed of the wet paper before and after the scraping device such as a creping doctor. For example, when the wet paper on the press roll 54 is scraped off by the creping doctor 55 and transferred to the bulky wire 16 at the subsequent stage as in the illustrated example, the crepe rate is calculated by the following equation. Crepe rate: {(peripheral speed of press roll) − (conveyance speed of bulky wire)} / (peripheral speed of press roll) × 100.

  In the method for manufacturing a paper towel according to the present invention, the wet paper web W3 to which the wet crepe has been applied in the creping step 2 is dried in the dryer part. In the dryer part P3, the wet paper web W3 is transferred to the Yankee dryer 60 via the touch roll 56 and dried.

  The drying step in the dryer part can be performed in the same manner as the known paper towel drying step. After being dried by the dryer 60 of the dryer part P3 and being converted from the wet W3 to the dry paper D1, the raw paper is transferred to an appropriate winding step to form the raw roll 70 on which the base paper of the paper towel is wound. When the dry paper is peeled off from the dryer 60, dry crepe may be applied.

  The raw roll 70 on which the base paper of the paper towel thus formed is wound is formed into a paper towel product through a known paper towel production process (not shown), for example, an embossing process and a folding process using an interfolder.

In the method for manufacturing a paper towel according to the present invention, particularly, in the former part 1 of the wire part P1, the moisture content on the felt 13 or the wire immediately after passing through the coucher roll 11 is 80% or more and the basis weight after drying is 20 to 50 g / m ^2. It is characterized in that 20 to 40% by mass of a nonionic surfactant solution 30 is added to paper by a shower or a spray at a rate of 1 to 7 kg per 1 ton of raw pulp, and further, wet crepe is imparted. On the other hand, the steps of the press part P2 and the dryer part P3 that greatly affect the mechanical structure of the paper, such as the basis weight, paper thickness, and density, can use the steps of the known paper towel manufacturing method as they are. Therefore, the paper strength and softness based on the mechanical structure of the paper, such as paper thickness and basis weight, are not inferior to those of conventional paper towels, and furthermore, the nonionic surfactant solution is adjusted by adjusting the addition position, amount and concentration of the nonionic surfactant solution. The improvement of the water absorption rate and the improvement of the softness by the surfactant solution are exerted without affecting the paper strength and the like.

  The effects of the method for producing a paper towel according to the present invention will be described with reference to examples. The results of the sensory evaluation such as physical property values and softness of each paper towel manufactured by the paper towel manufacturing method according to the present invention (Examples 1 to 5) and other paper towel manufacturing methods (Comparative Examples 1 to 7) are shown. It is shown in Table 1 below. In addition, the paper towel was used as a sample after performing the pop-up commercialization using an interfolder. The raw pulp according to Examples 1 to 3 and 5 and Comparative Examples 1 to 2 and 4 to 7 all uses the same 100% recycled pulp, and the raw pulp according to Example 4 and Comparative Example 3 uses 80% recycled pulp. LBKP 20% was used, and the same papermaking equipment was used.

  In addition, Comparative Examples 1 to 3 did not add a surfactant, and Comparative Examples 4 and 5 added a nonionic surfactant solution immediately after passing through a couchyroll, similarly to the paper towel according to the present invention. Are excessively small or large. Comparative Example 6 was obtained by adding a nonionic surfactant solution to a papermaking raw material, and Comparative Example 7 was obtained by adding a cationic surfactant instead of a nonionic surfactant to a papermaking raw material.

  In addition, the measuring method of the physical property value in a table | surface, and the criteria of sensory evaluation are as follows.

[Basic weight]
It was measured according to JIS P 8124 (1998).

(Paper thickness)
It was measured under the conditions of JIS P 8111 (1998) using a dial thickness gauge (thickness measuring device) “PEACOCK G type” (manufactured by Ozaki Seisakusho).

(Dry tensile strength)
It was measured according to the tensile test of JIS P 8113 (1998).

(Wet tensile strength)
It was measured according to the tensile test of JIS P 8135 (1998).

[Softness]
The measurement was performed according to the handle ometer method according to JIS L 1096 E method.

(Krem water absorption)
It was measured according to JIS P 8141 (2004).

(Bendable)
According to the 45 ° cantilever method, a test piece of 20 mm in width and about 150 mm in length is collected from a paper towel that has been made, set on a testing machine and gently slide the test piece in the direction of the slope, and one end of the test piece. The length (mm) at which the other end moved until the was in contact with the slope was measured. The shorter the length, the softer the test piece. Five measurements were performed for one test piece, and the average value was used as the measurement value of the flexibility.

(Water absorption speed)
According to the water absorption test according to JIS P 3104, 10 μl of distilled water was dropped on one surface of the sample, and the time until the illumination disappeared was measured. In addition, it was visually determined whether or not the shining had disappeared, and the dripping surface was a surface that was in contact with the wire or the felt surface during the papermaking. The measurement was performed five times for one sample, and the average value was used as the measured value of the water absorption rate.

〔sensory evaluation〕
The number of subjects in the sensory evaluation test was 30. In the sensory evaluation test, when the sample was used, a score was given as to how to evaluate the reference sample (Comparative Example 1) in terms of "blur", "softness", and "speed of water absorption". It was performed by attaching. For the reference sample, 4 points were evaluated as "very good", 3 points were evaluated as "slightly excellent", 2 points were evaluated as "slightly inferior", and "poor". The points evaluated as “Yes” were scored as one point, and the average score of each Example and Comparative Example (excluding Comparative Example 1) was determined.

In the table, "◎" indicates that the average score was 3.0 or more, "〇" indicates that the average score was 2.5 to 2.9, and "「 "indicates that the average score was 2.0 to 2.4. Δ, 1.9 or less are marked as “x”.

  In each of the results in Table 1, the paper towels according to Examples 1 to 5 manufactured according to the manufacturing method of the present invention are clearly marked with respect to the reference sample as indicated by “「 ”in all sensory evaluations. It was highly evaluated. Further, the water absorption speed is very fast, less than 5 seconds.

  On the other hand, in Comparative Examples 2 and 3 in which no surfactant was added, the sensory evaluation of softness was low, and the water absorption rate was 7 seconds or more. A similar tendency is observed in softness in softness.

  That is, in the production method according to the example according to the present invention, the water absorption rate and the softness are improved as compared with the production method in which the nonionic surfactant is not added. In particular, as for the water absorption rate, the method according to the production method of the present invention is improved by 30% or more as compared with Comparative Examples 1 to 3, and the effect can be confirmed very remarkably.

  Furthermore, comparing Examples 1 to 5 with Comparative Examples 4 and 5, the water absorption rate does not increase when the amount of the nonionic surfactant added is lower than the present invention, and when the addition amount is high, Tear is likely to occur. In particular, with respect to the tear of Comparative Example 5, the tensile strength in the dry and wet directions, particularly in the lateral direction, was very low, and it was found that sufficient strength could not be secured.

  In other words, the amount of the nonionic surfactant solution added must be within the range of the present invention in order to achieve the water absorption rate and softness and the sufficient strength according to the present invention.

  Furthermore, comparing Example 1 to Example 5 with Comparative Example 6, when the nonionic surfactant solution is used and the paper is added to the papermaking raw material, the water absorption rate and the development of softness are sufficient. Is not expressed.

  Then, comparing Example 1 to Example 5 and Comparative Example 7, when using a cationic surfactant instead of a nonionic surfactant and internally adding it to the papermaking raw material, the softness increases, Although the water absorption rate tends to be better than the internal addition of a nonionic surfactant solution, the paper strength does not increase and the paper tends to be broken. In other words, it can be seen that the cationic surfactant tends to be superior in water absorption rate and softness to the nonionic surfactant, but the paper strength is significantly reduced even by a method with a low yield such as internal addition.

  Comparing the examples and the comparative examples as described above, the method for producing a paper towel according to the present invention improves the softness and the water absorption rate of the paper towel, and maintains a sufficient strength.

  X1: round net papermaking equipment, 1: former part, 2: creping process, 11: couch roll, 13: felt (wire), 14: former (inlet), 15: shower device (spray device), 16: bulky wire, Reference Signs List 30 nonionic surfactant solution, 40 shatterproof cover, 54 press roll, 55 creping doctor, 56 touch roll, 60 Yankee dryer, 70 raw roll, W1 to W3 wet paper, D1 ... Dry paper, P1 ... Wire part, P2 ... Press part, P3 ... Dryer part.

Claims (5)

A method for producing a one-ply paper towel using pulp containing waste paper pulp as a raw material pulp,
In the former part of the wire part, 20 to 40% by mass of a nonionic interface with respect to the wet paper having a moisture content of 80% or more and a basis weight of 20 to 50 g / m ² after drying on the felt or the wire immediately after passing through the couch roll. Adding a surfactant solution by 1 to 7 kg per ton of raw pulp by shower or spray, a surfactant addition step,
A press part for dewatering the wet paper to which the nonionic surfactant solution has been added,
A crepe processing step of imparting wet crepe,
A method for producing a paper towel, comprising: a dryer part for drying wet crepe processed wet paper.   The method for producing a paper towel according to claim 1, wherein the nonionic surfactant solution is added such that the spraying direction of the shower or the spray and the conveying direction of the wet paper are at an angle of 50 degrees or less.   The method for producing a paper towel according to claim 1 or 2, wherein the nonionic surfactant is added to the wet paper web from above the scattering prevention cover covering the cooch roll.   The method for producing a paper towel according to any one of claims 1 to 3, wherein the slurry concentration of the papermaking raw material is 0.10 to 0.20% by mass.   The method for producing a paper towel according to any one of claims 1 to 4, wherein the creping rate in the creping step is 5 to 15%.

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