JP2006045690A - Method for producing sanitary tissue - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sanitary tissue having definitely and clearly applied emboss pattern. <P>SOLUTION: The sanitary tissue W is produced by passing a processing base paper Wo between embossing rolls E, R while heating the embossing roll E. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing sanitary thin paper such as tissue paper, toilet paper, towel paper, kitchen paper, and decorative paper.

  This type of sanitary thin paper has become a general-purpose technology to give embossing for the purpose of improving bulkiness, improving absorbency, improving wiping, improving touch feeling, and improving appearance. . Usually, such embossing is applied by passing the base paper to be processed through a metal roll having irregularities corresponding to male and female formed on the surface or between a metal roll and an elastic roll made of rubber or the like. Among these application methods, the former method has a characteristic that the uneven shape of the roll is easily transferred to the processed base paper as compared with the latter method. However, the former method may cause problems such as difficulty in adjusting the clearance of the roll in a long-term operation and clogging of the roll with paper powder or the like.

  By the way, many proposals have been made for embossing imparted to sanitary thin paper, and the present applicant has also made several proposals (see, for example, Patent Document 1 and Patent Document 2). For example, regarding the embossing of kitchen paper, a “Tip to Tip” form (see, for example, Patent Document 3), a “nested” form (see, for example, Patent Document 4), and the like have been proposed.

  As shown in FIG. 1, the former “Tip to Tip” configuration is such that the top of the embossed convex portion 101 </ b> A of one sheet 101 and the top of the embossed convex portion 102 </ b> A of the other sheet 102 are formed by an adhesive 3. It is to be glued. On the other hand, in the latter “nested” configuration, as shown in FIG. 2, the embossed convex portion 101A of one sheet 101 is fitted into the embossed concave portion 102B of the other sheet 102, and the space H is formed in the fitted region. The top part of the embossed convex part 1A and the bottom part of the embossed concave part 2B are bonded by the adhesive 3 so as to be formed. The kitchen paper provided with these embosses exhibits absorption performance by absorbing and retaining moisture and oil in the embossed space (H).

However, with the current technology, embossing cannot be given clearly and clearly, so the embossed space (H) cannot be formed accurately, and there is a problem that the absorption performance is not effectively exhibited. . In addition to the above “Tip to Tip” and “Nested” forms, there is also a “Random” form in which embossments with no regularity are added to the processed base paper for the purpose of improving the sense of thickness and appearance. However, since embossing cannot be given clearly and clearly, there is a problem that the feeling of thickness and appearance are not sufficiently improved. And since the problem that embossing cannot be provided clearly and clearly is caused by low basis weight, thin paper thickness, and the like, such a problem generally exists in sanitary thin paper. In particular, toilet paper and the like have a very low basis weight of 12.0 to 21.0 g / m ³ and a thickness of 80 to 160 μm, which is a serious problem.
JP 2002-88694 A JP 2004-130053 A JP-A-57-195430 JP-A-61-33628

  The main subject of this invention is providing the manufacturing method of the sanitary thin paper to which the emboss was provided clearly and clearly.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
A method of obtaining a sanitary thin paper by passing a processed base paper between embossing rolls,
A method for producing sanitary thin paper, wherein at least one of the embossing rolls is heated.

[Invention of Claim 2]
A method of obtaining a sanitary thin paper by passing a processed base paper between embossing rolls,
The said embossing roll consists of a metal roll which has an elastic roll and a heated embossing convex part, The manufacturing method of the sanitary thin paper characterized by the above-mentioned.

[Invention of Claim 3]
The manufacturing method of the sanitary thin paper of Claim 2 with which the Shore hardness of the elastic roll surface shall be 50-80.

[Invention of Claim 4]
The manufacturing method of the sanitary thin paper of any one of Claims 1-3 in which a to-be-processed base paper consists of 1 type, or 2 or more types of raw material raw materials chosen from the group of a pulp fiber, a recycled fiber, and rayon.

[Invention of Claim 5]
The surface temperature of a heating roll is 40-140 degreeC, The manufacturing method of the sanitary thin paper of any one of Claims 1-4.

[Invention of Claim 6]
The method for producing sanitary thin paper according to any one of claims 1 to 5, wherein the embossing pressure is 5 to 30 kg / cm.

  According to the method for producing sanitary thin paper of the present invention, sanitary thin paper to which embossing is given clearly and clearly is produced.

  Next, an embodiment of the present invention will be described. In the following, sanitary thin paper in general will be described first, and then kitchen paper, toilet paper, and tissue paper will be described as more specific examples.

[Manufacture of sanitary thin paper]
(Raw material)
In this production method, a raw paper is obtained from a raw material by, for example, making a raw pulp, and then embossed to the processed raw paper to obtain a sanitary thin paper. In the present specification, a base paper to be embossed is referred to as a processed base paper.

  The raw material of the processing base paper (hygienic thin paper) is not particularly limited, and an appropriate one can be used according to the use such as kitchen paper, toilet paper, tissue paper and the like. When pulp fiber is used as the raw material, the pulp fiber (raw pulp) is, for example, wood pulp, non-wood pulp, synthetic pulp, waste paper pulp, or the like, more specifically, groundwood pulp (GP). , Stone Grand Pulp (SGP), Refiner Grand Pulp (RGP), Pressurized Ground Pulp (PGW), Thermomechanical Pulp (TMP), Chemi Thermomechanical Pulp (CTMP), Bleach Chemi Thermomechanical Pulp (BCTMP) (MP), chemical mechanical pulp (CGP), semi-chemical pulp (SCP), hardwood bleached kraft pulp (LBKP), kraft pulp (KP) such as softwood bleached kraft pulp (NBKP), soda pulp (AP), monkey Chemical pulp such as fight pulp (SP), dissolving pulp (DP) CP), nylon, rayon, polyester, synthetic pulp made from polyvinyl alcohol (PVA), deinked pulp (DIP), waste paper pulp such as waist pulp (WP), ground pulp (TP), cotton, flax, hemp 1 type or several types are appropriately selected from rag pulp, straw pulp, esparto pulp, bagasse pulp, bamboo pulp, kenaf pulp and other auxiliary pulps such as bast pulp, etc. Can be used.

  However, the processed base paper is preferably made of one or more raw materials selected from the group of pulp fiber, recycled fiber and rayon. When these are used as raw materials, the effect of the present invention of providing embossing clearly and clearly is effectively exhibited by using a heated embossing roll.

(Paper making)
The raw material such as pulp fiber is processed into a raw paper through, for example, a known papermaking process, specifically, a wire part, a press part, a dryer part, a size press, a calendar part, and the like. In this papermaking, for example, suitable chemicals such as a dispersant, caustic soda, aqueous ammonia and other pH adjusters, antifoaming agents, preservatives, fluorescent dyes, mold release agents, water resistance agents, flow modifiers, yield improvers, etc. Can be added.

(Give emboss)
The processed base paper obtained by processing the raw material is passed through a pair of heated embossing rolls, and embossed to give sanitary thin paper. The embossing can be performed even if both of the pair of embossing rolls are heated or only one embossing roll is heated. When the embossing roll is heated, the embossing is given clearly and clearly.

  Both of the pair of embossing rolls may be metal rolls, but it is preferable that one is an elastic roll made of rubber or the like and the other is a metal roll having a heated embossed protrusion. The combination of the elastic roll and the metal roll is preferable because there is no problem of adjustment of the clearance of the roll or problems such as clogging of paper dust or the like in the roll.

  The heated embossing roll may be an elastic roll, but is preferably a metal roll. In addition to the fact that the metal roll has better thermal conductivity and exhibits the effect of heating effectively, when the metal roll is heated, it corresponds to the shape of the embossed base paper. This is because heat is applied to the surface and the embossing applied becomes clearer and clearer.

  The surface temperature of the heating roll is independent of whether the pair of embossing rolls are both metal rolls, a combination of an elastic roll and a metal roll, or which one of the elastic roll and the metal roll is heated. 40-140 ° C., preferably 60-120 ° C., more preferably 80-100 ° C. If the heating temperature is too low, the effect that the embossing becomes clear may not be sufficiently exhibited. On the other hand, if the heating temperature is too high, energy loss occurs, the processed base paper may be burned, and the manufactured sanitary thin paper may be hardened.

  The embossing is performed so that the embossing pressure between the pair of embossing rolls is 5 to 30 kg / cm, preferably 10 to 25 kg / cm, more preferably 15 to 20 kg / cm. If the embossing pressure is too low, the effect that the embossing becomes clear may not be sufficiently exhibited. On the other hand, if the embossing pressure is too high, the processed base paper may be torn.

  When the pair of embossing rolls is a combination of an elastic roll and a metal roll, the elastic roll preferably has a Shore hardness of 50 to 80 on the surface thereof. If the Shore hardness is too low, that is, if the elastic roll surface is too soft, the processed base paper may be broken. On the other hand, if the Shore hardness is too high, that is, if the surface of the elastic roll is too hard, there is a possibility that embossing does not enter.

  The shape of the emboss provided as described above is not particularly limited. For example, it is possible to design appropriately using factors such as the use and appearance of kitchen paper, toilet paper, tissue paper, and the like. The specific shape of the emboss will be described in detail below.

[Manufacture of kitchen paper]
Next, an example in which the household sanitary thin paper is kitchen paper will be described with reference to FIGS. 3 and 4.
In the manufacturing method of this embodiment, as shown in FIG. 4, two sheets 1 and 2 are bonded together, and the basis weight thereof is set to 10 to 50 g / m ² . If the basis weight is too small, wrinkles are likely to enter the sheet, and even if embossing is given clearly and clearly, the sheet is easily broken, so the effects of the present invention are reduced. On the other hand, if the basis weight is too large, flexibility is lowered.

  The bonding mode between the sheet 1 and the sheet 2 is a “Tip to Tip” form, and the top of the embossed protrusion 1A of one sheet 1 and the top of the embossed protrusion 2A of the other sheet 2 , CMC, MC, starch, etc. The embossing method is the same as in the case of “manufacturing sanitary thin paper” described above, and a heated embossing roll is used.

In the manufacturing method of this embodiment, the embossed shape is a cut quadrangular pyramid, but is not limited thereto. For example, it can be a cut-off cone, an ellipse whose top is planar, a triangle, or another polygon. In order to bond the sheets to each other, it is preferable to make the top portion flat. Area of the top portion, 0.1~40mm ^2, more preferably 0.25~4.0mm ^2, particularly preferably 0.5 to 2.0 mm ^2. It becomes impossible to obtain sufficient adhesive strength between sheets, where the top area is too narrow. On the other hand, if the area of the top is too large, the volume of the absorption space due to embossing becomes small, so that sufficient absorption capacity cannot be obtained. In addition, according to this invention, since embossing can be provided clearly and clearly, the above fine emboss shape design is also possible sufficiently.

  As shown in FIG. 3, a large number of the above-mentioned chevron-shaped embosses are regularly formed to form embossed sections X, X. No embossing is formed between the embossed sections X, X... And the sheet 1 and the sheet 2 are not bonded together. For example, a latticed patterned section Y such as a regular square, a rectangle, or a rhombus. Is forming. When the moisture and oil are absorbed by the punched pattern section Y, the moisture and oil are diffused along the section Y. Therefore, moisture and oil are quickly diffused along the section Y and absorbed and held in the absorption space by each emboss, so that it remains partly supersaturated and the emboss breaks down. Does not occur. The section Y can also be formed in a hexagonal shape, for example, but in this shape, almost no diffusive effect can be expected. On the other hand, when the section Y has a lattice shape, moisture and oil can be diffused far along the straight line of the lattice, so that the diffusibility is excellent.

  The length of one side of the grid of section Y is 1.731 mm to 50 mm, preferably 15 mm to 50 mm, and the width is 0.824 mm to 20 mm, preferably 1.2 mm to 5.0 mm. If the length of one side of the grating is too short, sufficient absorption by the embossed sections X, X... Cannot be obtained. On the other hand, if the length of one side of the grating is too long, the section Y cannot sufficiently diffuse in the plane direction.

  The area of the section Y is preferably 10 to 50% of the area of the embossed section X, and more preferably 20 to 30%.

  The total area of the part bonded by the adhesive 3 in the embossed section X is 5 to 30%, preferably 9 to 25%, particularly preferably 10 to 14.5% with respect to the area of the corresponding embossed section X. . If the total area of the bonded portions is too small, the volume of the absorption space increases, but sufficient adhesive strength between the sheets cannot be obtained. On the other hand, if the total area of the bonded portions is too large, the volume of the absorption space due to embossing is reduced, and sufficient absorption power cannot be obtained.

When two sheets of embossed sheets are stacked and the basis weight is 10 to 50 g / m ² , regardless of whether it is a “Tip to Tip” form or a “nested” form, etc. Regardless of the shape of the emboss, etc., the wet strength in the transverse direction of the two-ply sheets is set to be equal to or less than the wet strength in the longitudinal direction (machine direction) and the wet strength in the transverse direction. Is preferably 120 CN or more, and more preferably 150 CN or more. In general, many kitchen papers having a basis weight of 10 to 50 g / m ² that are currently marketed have a transverse wet strength of about 100 CN. However, in this embodiment, when the moisture and oil contained in tempura and deep-fried food are absorbed by increasing the wet strength in the lateral direction, the embossed that is clearly and clearly imparted does not collapse, and tempura and deep-fried food etc. There is no stickiness or sticking. By increasing the lateral wet strength, there is also an advantage that the sheet is hardly broken when the dirt is wiped off.

  In order to increase the wet strength in the horizontal direction of the kitchen paper, for example, a wet paper strength enhancer such as sponge is added to the raw pulp, the type of raw pulp is selected, or the beating of the raw pulp is strengthened. For example, the fixing of the wet paper strength enhancer can be enhanced. However, if the lateral wet strength is excessively increased, it becomes an impediment to sheet flexibility and the like, and therefore the lateral wet strength is preferably 500 CN or less, and more preferably 350 CN or less. On the other hand, the wet strength in the vertical direction can be selected as appropriate, but it is usually 1 or more times the horizontal wet strength.

[Manufacture of toilet paper]
Next, the case where the sanitary thin paper is toilet paper will be described as an example.
FIG. 5 is a partially enlarged plan view of the toilet paper W, and FIG. 6 is a cross-sectional view taken along the line I-I. In addition, in FIG.1 and FIG.2, the dimension of each part is shown.

  In the production of the toilet paper W, diamond-shaped embossing having a substantially flat top surface (top) T is provided. The shape of the top surface T can be, for example, a circle, an ellipse, or a polygon other than a rhombus. Further, the shape of the top surface T may be a star shape, for example, but if the top surface T has an elongated portion, it is not practical because the portion is easily damaged.

  The emboss has a maximum diameter a of 0.8 mm, a minimum diameter b of 0.4 mm, a long pitch A of 3.0 mm, and a short pitch B of 1.4 mm. Further, the embossing has a depth of 0.54 mm. And as shown in FIG. 6, the shape of the recessed part between top surface T, T ... is a shape in which a cross section does not have a curved part, and is a so-called trapezoidal embossing as a whole. The cross-sectional shape of the emboss may be an appropriate shape such as a trapezoidal type or a Mt. Fuji type. However, since the shape of the concave portion is unclear in the Mt. Fuji type, the effect of the present invention (appearance of clear and clear embossing) is more fully exhibited in the case of the trapezoid type. In addition, the trapezoidal shape is preferable in terms of appearance.

  According to this embodiment, the toilet paper W is smooth and less rough. This is because the emboss of a small area (about 1/3 of the conventional) is formed more per unit area (about 6 times the conventional) than the conventional form. . In addition, the toilet paper W is excellent in flexibility. This is because a lot of fine embosses are formed as in the case of smoothness, and each sheet of the toilet paper W is stiff. Further, the toilet paper W has a deep sinking depth of 9.68 mm (previously 7.48 mm), and thus has a soft feeling. In this respect, this effect cannot be obtained if embossing cannot be applied deeply. However, according to the present invention, embossing can be applied clearly and clearly, so that the depth can be ensured.

The basic weight of this toilet paper W is not specifically limited, For example, it can be set as 12.0-17.0 g / m < ² >. In this way, when the basis weight is small, it is generally said that embossing cannot be imparted clearly and clearly. However, according to the present invention, embossing can be imparted clearly and clearly. An embossed shape design is also possible. In this toilet paper W, about 47 top surfaces T, T · are formed per 10 mm ² .

  Specifically, the embossing can be performed by a heated metal roll E as shown in FIG. The metal roll E is provided with a plurality of protrusions (convex portions) on the surface, and the protrusions have the same shape as the emboss formed on the toilet paper W.

  In this method, the metal roll E is used, and the metal female roll R in which each protrusion (projection) fits between the elastic flexible roll whose surface to be paired is made of rubber or the like or in the recess of the metal roll E. As shown in FIG. 7, embossing is imparted by passing the processed raw paper Wo while niping it. In addition, the code | symbol 31 in FIG. 7 is a feeding roll, and the code | symbol 32 is a winding roll.

  The embossing method is not limited to the above method. For example, when the toilet paper has two plies, as shown in FIG. 8, an embossing device in which the elastic roll R2, the metal roll E, the metal roll E, and the elastic roll R2 are stacked in this order can be used. In this apparatus, one processed base paper Wo is passed between the lower elastic roll R2 and the metal roll E, and another processed base paper Wo is connected to the upper elastic roll R2 and the metal roll E. Both sheets passed between the rolls E and embossed by these sheets are passed between the lower metal roll E and the upper metal roll E, and the two sheets overlap. 2 ply toilet paper W.

[Manufacture of tissue paper]
Next, the case where the sanitary thin paper is tissue paper will be described as an example.
In the manufacturing method of the present embodiment, a pair (two plies) of tissue paper is formed by overlapping two sheets. Beitsubo based on JIS P 8124 of each sheet of the present tissue paper (one) (basis weight) is preferably set to 10~13g / m ^2, that the 11.9~12.7g / m ² More preferred. When the basis weight is less than 10 g / m ² , embossing is possible, but papermaking becomes difficult. On the other hand, when the basis weight exceeds 13 g / m ² , the softness is lowered, and the feeling of use and the drawability from the storage box are lowered.

  In the tissue paper, the paper thickness of a set of two stacked paper sheets is preferably 90 to 120 μm, and more preferably 94 to 112 μm. If the paper thickness is too thin, the feeling of paper thinness felt by the user becomes remarkable, and the water-absorbing property is poor and the function as tissue paper is lowered. On the other hand, if the paper thickness is too thick, the drawability when a predetermined number of sheets are stored in a storage box to produce a product is deteriorated. The tissue paper is preferably in the range of tensile strength, water absorption, and whiteness as defined in JIS S3104.

  The tissue paper is embossed by the heated embossing roll described above. As the shape of the emboss to be applied, for example, as shown in FIG. 9, rectangular embosses F, F... With rounded four corners can be exemplified. In the present embosses F, F..., The separation distance between the adjacent embosses F, F is 1.1 mm. The distance from one end of the emboss F to one end of the emboss F adjacent to the emboss F is 5.0 mm. Such an embossed pattern with a short separation distance is difficult to apply according to the conventional manufacturing method, but according to the manufacturing method of this embodiment, embossing F, F... It is. Of course, this embossed pattern can also be used for the kitchen paper and toilet paper described above.

  According to the manufacturing method of this embodiment, embossing can be imparted clearly and clearly. For example, an embossing pattern emphasizing design characteristics such as Japanese Patent Application Laid-Open No. 2004-130053 can be suitably imparted.

Next, examples of the present invention will be described.
Embossing was given to each of the processing base paper for toilet paper and the processing base paper for kitchen paper through an elastic roll and a metal roll having an embossed protrusion. The embossing was performed in three ways: when the metal roll was not heated (conventional example), when heated to 60 ° C. (Example), and when heated to 140 ° C. (Example). In addition, the processed base paper for toilet paper made pulp the main raw material, and set the basic weight to 17.0 g / m < ² >. Moreover, the processed paper for kitchen paper was made of pulp as a main raw material, and a polyamide polyamine epichlorohydrin resin was used as a wet paper strength agent, with a basis weight of 22.0 g / m ² .

[Test Example 1]
The paper thickness (μm) of the toilet paper and kitchen paper after embossing was measured. The measurement of the paper thickness was performed using a Peacock G type probe diameter of 10 mmφ manufactured by Ozaki Seisakusho. Specifically, confirm that there is no dust, dust, etc. between the plunger and the measuring table, lower the plunger on the measuring table, move the gauge memory to the zero point, and then move the plunger The sample (toilet paper or kitchen paper) was placed on the measuring table, the plunger was lowered, and the gauge at that time was read. At this time, the plunger was only placed on the sample. In addition, the measurement was performed by 1 sheet and it was set as the average value of 10 times. The results are shown in Table 1.

[Test Example 2]
About the toilet paper and kitchen paper after providing embossing, the paper thickness (micrometer) was measured by the method similar to Test Example 1. However, in this test, the plunger was dropped onto the sample from a height of 700 μm. The results are shown in Table 2.

[Test Example 3]
About the toilet paper and kitchen paper after providing embossing, the volume (micrometer) was measured by the method similar to Test Example 1. However, in this test, the probe diameter was 30 mmφ. The results are shown in Table 3.

[Test Example 4]
About the toilet paper and kitchen paper after providing embossing, the volume (micrometer) was measured by the method similar to Test Example 2. However, in this test, the probe diameter was 30 mmφ. The results are shown in Table 4.

[Test Examples 5 to 8]
The bending rigidity (B) and bending hysteresis (2HB) of the toilet paper and kitchen paper after embossing were measured. This bending property test was performed using an automated pure bending tester “KESFB2-AUTO-A” manufactured by Kato Tech Co., Ltd. As shown in FIG. 10, a specific method for this measurement is as follows. After a sample having a width of 20 cm is bent to the front side to a maximum curvature of 2.5 cm ⁻¹ by pure bending with a chuck interval of 1 cm and always maintaining an arc. This evaluates the relationship between the curvature and the bending moment when returning to the original and then bending back to the maximum curvature of -2.5 cm ^-1 and then returning to the original. This relationship is obtained as a value on the hysteresis curve shown in FIG. 11, and the bending rigidity (B) of the sample is expressed as an average inclination between curvatures of 0.5 to 1.5 cm ⁻¹ . In addition, it is hard to bend and it is so hard that bending rigidity (B) is large. The bending hysteresis (2HB) of the sample is expressed by the average hysteresis width of the bending moment between the curvatures of 0.5 to 1.5 cm ⁻¹ . A larger bending hysteresis (2HB) means that the bending recovery is worse (lower). Bending rigidity (B) longitudinal (MD: Machine Direction) results are shown in Table 5, lateral (CD: Cross Direction) results are shown in Table 6, bending hysteresis (2HB) longitudinal results are shown in Table 7, and horizontal results are shown in Table 7. Table 8 shows.

  The production method of the present invention can be applied to the production of sanitary thin paper used in homes such as tissue paper, toilet paper, towel paper, kitchen paper, and decorative paper.

It is explanatory drawing of the joining form of "Tip to Tip". It is explanatory drawing of the joining form of "nested". It is a top view which shows the embossing pattern of kitchen paper. It is sectional drawing which shows the embossing pattern of kitchen paper. It is a top view which shows the embossing pattern of toilet paper. It is the II sectional view taken on the line of FIG. It is a figure which shows the provision method of embossing. It is a figure which shows the provision method of embossing. It is a top view which shows the embossing pattern of tissue paper. It is explanatory drawing of the test method of a bending characteristic. It is a relationship figure of a bending characteristic.

Explanation of symbols

  1, 2 ... sheet, 3 ... adhesive, E ... metal roll, R1, R2 ... elastic roll.

Claims (6)

A method of obtaining a sanitary thin paper by passing a processed base paper between embossing rolls,
A method for producing sanitary thin paper, wherein at least one of the embossing rolls is heated. A method of obtaining a sanitary thin paper by passing a processed base paper between embossing rolls,
The said embossing roll consists of a metal roll which has an elastic roll and a heated embossing convex part, The manufacturing method of the sanitary thin paper characterized by the above-mentioned.   The manufacturing method of the sanitary thin paper of Claim 2 with which the Shore hardness of the elastic roll surface shall be 50-80.   The manufacturing method of the sanitary thin paper of any one of Claims 1-3 in which a to-be-processed base paper consists of 1 type, or 2 or more types of raw material raw materials chosen from the group of a pulp fiber, a recycled fiber, and rayon.   The surface temperature of a heating roll is 40-140 degreeC, The manufacturing method of the sanitary thin paper of any one of Claims 1-4.   The method for producing sanitary thin paper according to any one of claims 1 to 5, wherein the embossing pressure is 5 to 30 kg / cm.

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