JP2020190045A - Nonwoven fabric manufacturing method - Google Patents

Abstract

To provide a nonwoven fabric manufacturing method that can homogenize a coating amount of a functional agent.SOLUTION: A nonwoven fabric manufacturing method has a process to sandwich a nonwoven fabric base material between a roll circumferential surface of a transfer cylinder that transfers a coating liquid containing a functional agent and a roll circumferential surface of an impression cylinder that applies printing pressure to coat the surface of the nonwoven fabric base material with the functional agent. In the process, the printing pressure of 210 kPa or higher is applied to the nonwoven fabric base material and warp of the transfer cylinder and the impression cylinder during pushing-in is corrected to reduce the difference of push-in amount in a roll axis direction of the coating end and the coating center portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a non-woven fabric.

In recent years, in various articles such as absorbent articles and cleaning sheets, non-woven fabrics containing a functional agent according to the purpose have been used. For example, in an absorbent article, a non-woven fabric coated with a hydrophilic agent, a skin care agent, or the like is used as a surface sheet or the like. Further, in the cleaning sheet, a non-woven fabric coated with a cleaning agent, wax or the like is used.
Techniques for applying such a functional agent to a non-woven fabric substrate have also been developed. For example, Patent Document 1 describes a technique of applying a hydrophilic fiber treatment agent to a polyolefin fiber and then forming it into a non-woven fabric. Further, it is described that a hydrophilic agent is blended with a polyolefin resin to form a non-woven fabric using melt-spun hydrophilic polyolefin fibers. In addition to this, a technique of immersing a raw material non-woven fabric in a coating liquid of a functional agent is known.

Japanese Unexamined Patent Publication No. 2000-80559

In the non-woven fabric having the above-mentioned functional agent, it is required that the functional agent is uniformly coated on the surface of the non-woven fabric from the viewpoint of fully exerting the performance of the article. However, as in the invention described in Patent Document 1, when the fibers are preliminarily contained with a functional agent to form a non-woven fabric, the obtained non-woven fabric is coated with the functional agent according to the fiber density distribution (roughness of texture). Unevenness may occur. This unevenness of the functional agent can occur even when the raw material non-woven fabric is immersed in the coating liquid of the functional agent.
Further, when the function of the functional agent is exerted on the surface of the non-woven fabric, it is required that the required amount is present on the surface of the non-woven fabric. However, in the conventional technique as described above, it is difficult to control the homogenization of the coating amount because the functional agent diffuses in the thickness direction.
The homogenization of the coating amount referred to here means that the fluctuation of the coating amount and the occurrence of the coating amount distribution in the coating width direction are suppressed at the same time. The "coating amount fluctuation" means the magnitude of variation under the same coating conditions, and the "coating amount distribution" means the distribution of the average value of the coating amount. The width direction is a direction orthogonal to the transport direction (machine flow direction) of the non-woven fabric in the method for manufacturing the non-woven fabric, and coincides with the roll axis direction of the coating roll and the width direction of the non-woven fabric. The transport direction is also referred to as an MD direction (Machine Direction), and the width direction is also referred to as a CD direction (Cross Direction).

The present invention relates to a method for producing a non-woven fabric capable of homogenizing the amount of a functional agent applied.

In the present invention, a non-woven fabric base material is sandwiched between a roll peripheral surface of a transfer cylinder that transfers a coating liquid containing a functional agent and a roll peripheral surface of an impression cylinder that applies printing pressure, and is placed on the surface of the non-woven fabric base material. A step of applying the functional agent is provided, and in the step, a printing pressure of 210 kPa or more is applied to the non-woven fabric base material, and the deflection of the transfer cylinder and the impression cylinder at the time of pressing is corrected, and a roll is provided. Provided is a method for producing a non-woven fabric, which suppresses the difference in the amount of pushing in between the coating end portion and the coating center portion in the axial direction.
Further, in the present invention, the non-woven fabric base material is sandwiched between the roll peripheral surface of the transfer cylinder for transferring the coating liquid containing the functional agent and the roll peripheral surface of the impression cylinder for applying the printing pressure. The surface is provided with a coating portion for applying the functional agent, and the coating portion applies a printing pressure of 210 kPa or more to the non-woven fabric base material, and the transfer cylinder and the impression cylinder at the time of pushing. Provided is a non-woven fabric manufacturing apparatus capable of performing the coating by suppressing a difference in the amount of pushing between the coating end portion and the coating center portion in the roll axis direction by the deflection correction mechanism.

According to the method for producing a non-woven fabric of the present invention, it is possible to produce a non-woven fabric in which the amount of the functional agent applied is homogenized.

(A) is a schematic block diagram which shows a preferable embodiment of the coating part in the manufacturing apparatus used in the manufacturing method of the nonwoven fabric of this invention, (B) is the roll of the transfer cylinder (plate cylinder) shown in (A). It is a partially enlarged sectional view which shows the part on the surface side. (A) is a graph showing the relationship between the thickness of the air-through non-woven fabric base material and compressive stress (printing pressure), and (B) is a graph showing the relationship between the thickness of the spunbonded non-woven fabric base material and compressive stress. C) is a graph showing the relationship between the paper substrate and the compressive stress. (A) is an explanatory diagram of a compression test performed without sandwiching the base material to be coated, and (B) is an explanatory diagram of a compression test performed by sandwiching the base material to be coated. As a result of measurement by the method of FIG. 3 (A) without arranging the base material to be coated, and to the base material to be coated used in FIGS. 2 (A), (B) and (C). 3 is a graph showing the relationship between the roll pressing amount and the printing pressure as a result of measurement by the method of FIG. 3B. The relationship between the printing pressure and the coating amount as a result of coating the base material to be coated used in FIGS. 2 (A), (B) and (C) using the single-wafer coating apparatus is shown. It is a graph which shows. From the result obtained in FIG. 5, it is a graph which shows the relationship between the printing pressure and the coefficient of variation of the coating amount. In (A), the sheet-fed coating apparatus used in FIG. 5 was used for the base material (air-through non-woven fabric base material) to be coated used in FIG. 2 (A), and the anilox rolls were made into honeycomb 800 Lpi and honeycomb 1800 Lpi. It is a graph which shows the relationship between the printing pressure and the coating amount as a result of performing coating with two types of coating, and (B) is a coefficient of variation of printing pressure and coating amount from the result obtained in (A). It is a graph which shows the relationship with. In (A), the base material (air-through non-woven fabric base material) to be coated used in FIG. 2 (A) is coated by using the single-wafer coating apparatus used in FIG. 5 and changing the coating liquid. It is a graph which shows the relationship between the printing pressure and the coating amount of the result, and (B) is the graph which shows the relationship between the printing pressure and the coefficient of variation of the coating amount from the result obtained in (A). (A) is a partially enlarged side view showing a position where the transfer cylinder and the impression cylinder are in contact with each other, and (B) is a partially enlarged side view showing a position where the transfer cylinder and the impression cylinder are in contact with each other. It is a top view which shows typically the arrangement of the impression cylinder, the transfer cylinder and the anilox roll, and the direction of the pushing load about the coating part shown in FIG. FIG. 10 is a plan view schematically showing a state in which the transfer cylinder is bent in the roll axis direction due to the pushing load at the end of the roll shaft in the arrangement shown in FIG. (A) is a graph showing the distribution of the actual pushing amount in the roll axis direction (CD direction) of the transfer cylinder, and (B) shows the coating amount distribution of the functional agent in the roll axis direction (CD direction) of the transfer cylinder. It is a graph, and (C) is a graph which calculates and shows the relationship between the actual pushing amount and the coating amount between the transfer cylinder 1 and the impression cylinder 2. It is a top view which shows typically the mode of arranging the deflection correction roll in the arrangement shown in FIG. It is a schematic block diagram which shows another preferable embodiment of the coating part in the manufacturing apparatus used in the manufacturing method of the nonwoven fabric of this invention.

Hereinafter, the method for producing a nonwoven fabric of the present invention will be described based on the preferred embodiment thereof with reference to the drawings.

First, in the present invention, the non-woven fabric base material to be coated with the functional agent (hereinafter, also referred to as raw material non-woven fabric) can be manufactured by various methods using various commonly used manufacturing devices. For example, a method of forming a fiber web and then binding the fibers to form a non-woven fabric, and a spinning direct-coupled method of injecting a molten resin from a nozzle to directly form a non-woven fabric can be mentioned. Bonding of fibers to each other in the fiber web can be performed by various commonly used methods. Examples thereof include bonding methods such as chemical bonding, thermal bonding, and mechanic bonding. Chemical bonding is a method using an adhesive (binder), and examples thereof include air-laid non-woven fabrics using dry pulp. Thermal bonding includes a calendar method and an air-through method, both of which use heat-sealing fibers. The non-woven fabric obtained by the air-through method is called an air-through non-woven fabric. Mechanic carboning includes a needle punching method and a water flow confounding method. Further, examples of the non-woven fabric obtained by the above-mentioned direct spinning method include spunbonded non-woven fabrics and melt-blown non-woven fabrics. The air-through non-woven fabric is soft to the touch and highly compressible. Further, the air-through nonwoven fabric can be made bulky and thick by setting the basis weight for forming the fiber web. On the other hand, the spunbonded non-woven fabric has excellent strength and abrasion resistance, is more rigid than the air-through non-woven fabric, and has low compressibility.

As the non-woven fabric base material to which the functional agent is applied as described above, various materials are targeted, and the basis weight and thickness of the non-woven fabric base material can also be various. For example, when producing a nonwoven fabric for an absorbent article, the basis weight of the nonwoven fabric base material is preferably 9 g / m ² or more, more preferably 15 g / m ² or more, and preferably 80 g / m ² or less, preferably 45 g / m ^2. More preferably m ² or less.
When producing a non-woven fabric for an absorbent article, the value obtained by dividing the thickness of the non-woven fabric base material under a load of 210 kPa by the thickness of the non-woven fabric base material under a load of 315 kPa is preferably 1.05 or more, preferably 1.08. The above is more preferable, 1.1 or more is further preferable, 1.25 or less is preferable, 1.2 or less is more preferable, and 1.16 or less is further preferable. The value obtained by dividing the thickness of the non-woven fabric base material under a load of 140 kPa by the thickness of the non-woven fabric base material under a load of 210 kPa is preferably 1.02 or more, more preferably 1.05 or more, still more preferably 1.08 or more. Further, 1.25 or less is preferable, 1.18 or less is more preferable, and 1.15 or less is further preferable. The value obtained by dividing the thickness of the non-woven fabric base material under a load of 140 kPa by the thickness of the non-woven fabric base material under a load of 315 kPa is preferably 1.05 or more, more preferably 1.1 or more, still more preferably 1.2 or more. Further, 1.4 or less is preferable, 1.35 or less is more preferable, and 1.32 or less is further preferable.

In the present invention, the functional agent is applied to the above-mentioned non-woven fabric base material by the method shown below. The term "functional agent" as used herein refers to an agent having the expected functions in an article in which a non-woven fabric is incorporated. For example, in the non-woven fabric applied to the surface sheet of an absorbent article, a hydrophilic agent, a skin care agent, a liquid film cleaving agent and the like can be mentioned. Further, examples of the non-woven fabric applied to the cleaning sheet include cleaning agents and waxes.

1A and 1B show a preferred embodiment of a coating unit (coating apparatus) 10A in the manufacturing apparatus used in the method for producing a nonwoven fabric of the present invention. In the method for producing a non-woven fabric of the present embodiment, the non-woven fabric base material 8 is formed by using a commonly used manufacturing apparatus, and a coating liquid containing a functional agent is uniformly applied to the surface of the non-woven fabric base material in the coating portion 10A. To work. It should be noted that the present invention is not limited to the coating method by the coating portion shown in FIGS. 1A and 1B, and the printing pressure is controlled within a specific range by the transfer cylinder and the impression cylinder. The method of coating and the coating portion can be appropriately used.

The coating unit 10A has a transfer cylinder 1 that holds and transfers the coating liquid containing the functional liquid, and an impression cylinder 2 that applies printing pressure. The transfer cylinder 1 and the impression cylinder 2 are arranged to face each other and are rotatable. As a result, the non-woven fabric base material (raw non-woven fabric) 8 is sandwiched between the roll peripheral surface of the transfer cylinder 1 and the roll peripheral surface of the impression cylinder 2, and the functional agent is applied to the surface of the non-woven fabric base material 8. The coated non-woven fabric base material 8 is sent to a subsequent process in accordance with the rotation of the transfer cylinder 1 and the impression cylinder 2. In this way, the coating unit 10A performs the coating process of the coating liquid containing the functional liquid.

The transfer cylinder 1 is a plate cylinder in the flexographic coating method, and is provided with a coating plate 13 on the surface of the cylinder body 11 via a cushion tape 12. The coating plate (flexographic plate) 13 is made of a flexible and elastic material such as rubber or synthetic resin, and forms a soft roll peripheral surface of the transfer cylinder 1. The transfer cylinder 1 has a plurality of convex portions 14 for holding the coating liquid of the functional agent on the coating plate 13 on the peripheral surface of the roll. The impression cylinder 2 is made of a rigid material such as metal, and applies pressure to the soft roll peripheral surface of the transfer cylinder 1. By pressurizing the impression cylinder 2, the coating liquid held on the roll peripheral surface of the transfer cylinder 1 can be stably applied to the non-woven fabric base material 8. The surfaces of the cylinder body 11 and the impression cylinder 2 are preferably smooth, and specifically, the arithmetic mean roughness Ra of the surfaces is preferably smaller than 6.3 μm. Further, the rolls used other than the transfer cylinder 1, the impression cylinder 2, and the anilox roll 3 described later (for example, a free roll used for transporting a base material, a drive roll, etc., not shown) have an arithmetic average roughness Ra. It is preferably 6.3 um or less.

Further, the coating unit 10A has an anilox roll 3 arranged so as to come into contact with the transfer cylinder 1 and rotatably formed, and a coating chamber 4 for supplying the coating liquid to the anilox roll 3. The anilox roll 3 has a plurality of concave cells on the peripheral surface of the roll. The roll peripheral surface of the anilox roll 3 is rotated so as to be immersed in the coating liquid of the coating liquid chamber 4, and the concave cell is filled with the coating liquid. At that time, a doctor blade (not shown) is pressed against the surface of the Anilox roll 3 to scrape off excess coating liquid. Next, the Anilox roll 3 transfers the coating liquid in the concave cell to the convex portion 14 of the coating plate 13 of the transfer cylinder 1.

In the method for producing a non-woven fabric of the present embodiment, the coating part 10A of FIG. 1 is used to control the printing pressure on the non-woven fabric base material 8 within a specific range, and the non-woven fabric base material 8 is coated with a coating liquid containing a functional agent. To do.
Conventionally, a printing method of transferring ink by printing pressure, typified by flexography, has been generally used for objects to be coated such as paper and film. In this method, coating is performed with a low printing pressure that touches the surface of paper or the like. Such a low printing pressure condition is called a kiss touch condition. The kiss-touch condition is that a weak pressing of about 76.2 μm is applied to the object to be coated, where the true contact area and capillary force between the plate and the printed surface are difficult to change due to the conventional compressive stress (printing pressure) of paper or film. It is said to be the printing pressure to be applied. This is considered to correspond to a printing pressure of about 140 kPa as measured based on the following (method for specifying the printing pressure). In such a low printing pressure coating, the transfer method is such that the coating liquid is placed on the surface of the object to be coated. Conventionally, even with high-viscosity ink for printing, the amount of ink transfer is determined by the surface tension difference between the plate and the printing surface, the true contact area and the capillary force, so the compressive stress determines the true contact area between the plate and the printing surface. The target printed surface was formed on the object to be coated, in which the capillary force was difficult to change.
However, when the non-woven fabric base material is to be coated, since the non-woven fabric base material is a material having higher compressibility than paper or the like, in the conventional printing method as described above, the true contact area between the plate and the coated surface It is difficult to uniformly and sufficiently exert the function of the functional agent on the entire surface of the non-woven fabric because the coating amount fluctuates due to the unevenness of the capillary force and the coating amount.

For example, an air-through non-woven fabric having a basis weight of 21 g / m ² using a sheath-type composite fiber (core: polyethylene terephthalate resin fiber, sheath: polyethylene resin fiber) having a fineness of 1.3 dtex shown in FIG. 2 (A) (hereinafter, non-woven fabric base material). The thickness of (E1) is 569 μm under a compressive stress of 1 kPa, whereas it changes to 82 μm under a compressive stress of 140 kPa, 72 μm under a compressive stress of 210 kPa, and 63 μm under a compressive stress of 315 kPa. The thickness of polypropylene spunbonded non-woven fabric SF-max (trade name) (hereinafter referred to as non-woven fabric base material E2) manufactured by Toray Advanced Materials Korea, which has a basis weight of 17 g / m ² shown in FIG. 2 (B), is 148 μm under a compressive stress of 1 kPa. On the other hand, it changes to 71 μm under a compressive stress of 140 kPa, 65 μm under a compressive stress of 210 kPa, and 59 μm under a compressive stress of 315 kPa.
On the other hand, the thickness of the copy paper G80A4W (trade name) (hereinafter referred to as paper base material C1) manufactured by Mitsubishi Paper Mills Limited with a basis weight of 64 g / m ² shown in FIG. 2 (C) is 66 μm under a compressive stress of 1 kPa. There is almost no change of 63 μm under a compressive stress of 140 kPa, 63 μm under a compressive stress of 210 kPa, and 62 μm under a compressive stress of 315 kPa.
Considering these facts, it can be said that the non-woven fabric base material 8 is a base material having high compressibility, and the true contact area between the plate and the coated surface and the capillary force are easily changed by compressive stress.

On the other hand, in the present invention, as a means for quantitatively applying the functional agent to the non-woven fabric base material 8, a method of transferring the coating liquid by a printing pressure such as flexography is used, and the coated surface of the non-woven fabric base material 8 having high compressibility ( A printing pressure of 210 kPa or more is applied to the surface of the non-woven fabric). By applying a high printing pressure, which is not normally performed in the past, the coating liquid containing the functional agent can be applied by making it less susceptible to the true contact area of the coated surface of the coating plate 13 and the non-woven fabric base material 8 and uneven capillary force. Apply to the surface of the non-woven fabric substrate. As a result, it is possible to suppress fluctuations in the coating amount of the coating liquid containing the functional agent on the nonwoven fabric base material 8.

The above-mentioned suppression of the variation in the coating amount is performed by applying the same printing pressure to the non-woven fabric base material 8 to intermittently acquire a base material during a plurality of coatings or continuous coating. It means that the coefficient of variation of the coating amount in the coating area on the surface of the surface is small. Specifically, it means that the coefficient of variation of the coating amount distribution is 6% or less. The coating amount is determined by the amount of the functional agent contained in the coating liquid in the produced nonwoven fabric. The method for measuring the coefficient of variation of the coating amount is as follows.

(Measuring method of coefficient of variation of coating amount)
(1) The amount of coating is
Measurement of mass difference of non-woven fabric before and after coating of 200 cm ² or less, or
The difference between the mass of the non-woven fabric after coating and the mass of the non-woven fabric obtained by extracting the coated agent of the non-woven fabric after coating with a solvent or drying the non-woven fabric after coating, or even when the coating agent consists of multiple components, the extract is used. It can be calculated by multiplying the mass ratio obtained by separating and isolating the extract using liquid chromatography by the mass difference before and after the extraction, and dividing by the coating area.
(2) The coefficient of variation of the coating amount can be calculated by dividing the standard deviation of the coating amount calculated for a population of n = 10 or more by the average value.

(Measuring method of printing pressure)
The printing pressure applied to the non-woven fabric base material 8 can be measured by the following compression test.
First, as shown in FIG. 3A, the cushion tape 12 and the coating plate 13 included in the transfer cylinder 1 are placed and fixed on the table 71. The push-in plate 72 is placed on the coating plate 13, and the load cell 73 is placed on the push-in plate 72. At this time, the base material to be coated is not sandwiched between the coating plate 13 and the pressing plate 72. The base 71 is made of the same material as the cylinder body 11 included in the transfer cylinder 1, and the push plate 72 is made of the same material as the impression cylinder 2.
Next, compression is performed with a pushing amount of 76.2 μm (kiss touch condition), the corresponding compressive load is measured by the load cell 73, and the compressive stress under the kiss touch condition can be measured by dividing by the cross-sectional area of the compressed material. Also, the coordinates at the start of compression are set as the origin. It is considered that there is almost no difference in the measurement results of a base material having low compressibility such as paper, whether or not it is sandwiched between the coating plate 13 and the pressing plate 72. Therefore, the compressive stress corresponding to the kiss-touch condition obtained by the above measurement can be regarded as corresponding to the printing pressure when the substrate having low compressibility such as paper is pressed under the kiss-touch condition.
While holding the origin, as shown in FIG. 3B, the base material to be coated is sandwiched between the coating plate 13 and the pressing plate 72, and the pressing amount and the corresponding compressive load are measured. , The compressive stress is measured by dividing by the cross-sectional area of the compression material. When the indentation amount in this measurement is read as the roll indentation amount used for managing the coating conditions in the actual coating, the compressive stress corresponds to the printing pressure applied to the base material to be coated. That is, it is possible to quantify the printing pressure applied at the time of coating for each substrate to be coated.

As for the correspondence between the pressing amount and the printing pressure specified in the above (method for measuring the printing pressure), for example, the relationship shown in FIG. 4 can be seen. Series A in FIG. 4 shows the results of measurement by the method of FIG. 3 (A) without arranging the base material to be coated. The series B to C in FIG. 4 are shown in FIG. 3 (B) with respect to the non-woven fabric base material E1, the non-woven fabric base material E2 and the paper base material C1 used in FIGS. 2 (A), (B) and (C), respectively. The result measured by the method is shown. The measurement of each series in FIG. 4 was performed under the following device conditions.
(Device conditions)
Cushion tape 12: "E1020H" (trade name, manufactured by Sumitomo 3M Ltd., thickness 0.5 mm)
Coating version 13: "DSF" (trade name, manufactured by Asahi Kasei E-Materials Co., Ltd., thickness 1.7 mm, shore A hardness 62 °)

As can be seen from the comparison between the series B and the series C and the series D in FIG. 4, a larger pressing amount is applied to the non-woven fabric base material even if the printing pressure is the same, as compared with the case of paper. This is because, as described above, the non-woven fabric base material has higher compressibility than paper.

As shown in FIG. 4, when the non-woven fabric base material having high compressibility is attempted to be coated with the non-woven fabric base material (small printing machine) shown below, (1) the printing pressure is increased. It was confirmed that the coating amount increased and (2) the fluctuation of the coating amount became stable when the printing pressure was increased. From this, it can be seen that in the coating of the functional agent on the non-woven fabric base material, the suppression of the fluctuation in the coating amount can be realized by applying a printing pressure of a certain level or more.

The coating using the above single-wafer coating apparatus was performed under the following conditions.
(I) Base material conditions Base material: Non-woven fabric base material E1, non-woven fabric base material E2, paper base material C1 described above
Each base material had a CD width of 70 mm × MD length of 200 mm, and the coating area of each base material had a CD width of 60 mm × MD length of 200 mm (whole surface coating). The MD length is the length in the MD direction. The CD width is the length in the CD direction.
(Ii) Equipment conditions Coating equipment 10A: Desktop flexographic printing machine FLEXIPROOF100 (trade name, manufactured by RK Print Coat Instruments Ltd.)
Cushion tape 12: "E1020H" (trade name, manufactured by Sumitomo 3M Ltd., thickness 0.5 mm)
Coating version 13: "DSF" (trade name, manufactured by Asahi Kasei E-Materials Co., Ltd., thickness 1.7 mm, shore A hardness 62 °)
Anilox Roll 3: Honeycomb 800Lpi (3.0cc / m ² ) engraving specifications Coating speed: 70m / min
(Iii) Coating liquid Polyether-modified silicone "KF-6015" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) Viscosity of coating liquid: 130 mPa · sec at a temperature of 25 ° C.

Under the above conditions, the coating amount (average value) of the coating liquid was measured by changing the printing pressure on the nonwoven fabric base material E1, the nonwoven fabric base material E2, and the paper base material C1. The coating amount was an average value calculated by dividing the difference in mass of the base material before and after coating by the printed area (60 mm × 200 mm) at N = 10. The results are shown in Table 1 and FIG. 5 below.
Further, the value calculated by dividing the standard deviation of the coating amount calculated for the population of N = 10 by the average value was used as the coefficient of variation of the coating amount. The results are shown in Table 2 and FIG. 6 below.

As shown in Table 1 and FIG. 5, the coating amount of the paper base material C1 (-▲-) was substantially constant even when the printing pressure was increased, whereas the non-woven fabric base material E1 (air-through non-woven fabric,-◆-). And the non-woven fabric base material E2 (spun-bonded non-woven fabric, − ■ −) increased the coating amount as the printing pressure was increased.
Further, as shown in Table 2 and FIG. 6, the paper base material C1 (-▲-) did not change the coefficient of variation of the coating amount even when the printing pressure was increased, whereas the non-woven fabric base material E1 (air-through non-woven fabric, -◆-) and the non-woven fabric base material E2 (spun-bonded non-woven fabric,-■-) became stable as the coefficient of variation of the coating amount decreased as the printing pressure increased.
As described above, in the coating of the functional agent on the non-woven fabric base material, by applying a printing pressure higher than a certain level, that is, a printing pressure of 210 kPa or more, fluctuations in the coating amount are effectively suppressed and good coating is performed. Can work.

It can be seen that such a tendency occurs regardless of the amount of the coating liquid shown in Tables 3 and 7 below and the type of coating liquid (physical properties such as viscosity and hydrophilicity) shown in Tables 4 and 8. ..

For example, in Tables 3 and 7, the amount of the coating liquid was changed as follows with respect to the nonwoven fabric base material E1 (air-through nonwoven fabric), and the coating amounts of Tables 1 and 5 were measured, and Tables 2 and 6 showed. The results of measurement under the same conditions as the measurement of the coefficient of variation of the coating amount are shown.
Series indicated by "-◆-": Anilox Roll Honeycomb 800Lpi (3.0cc / m ² )
Series indicated by "-■-": Anilox roll honeycomb 1800 Lpi (1.3 cc / m ² )
As shown in Table 3 (A) and FIG. 7 (A), the coating amount on the non-woven fabric base material E1 increased as the printing pressure was increased, regardless of the amount of the coating liquid. Further, as shown in Table 3 (B) and FIG. 7 (B), the coefficient of variation of the coating amount on the non-woven fabric base material E1 becomes lower and stabilized as the printing pressure is increased regardless of the amount of the coating liquid. did.

Further, for example, in Tables 4 and 8, the functional agent to be coated on the nonwoven fabric base material E1 (air-through nonwoven fabric) is changed as follows, and the coating amount in Tables 1 and 5 is measured, Table 2 and FIG. The result of measurement under the same conditions as the measurement of the coefficient of variation of the coating amount in FIG. 6 is shown.
Series indicated by "-◆-": The above-mentioned polyether-modified silicone "KF-6015"
Series indicated by "-■-": "FZ-2203i" (trade name, manufactured by Toray Dow Corning Co., Ltd.), viscosity of coating liquid: 4731 mPa · sec at a temperature of 25 ° C.
Series indicated by [-▲-]: Glycerin diluted to 50% by mass with deionized water, viscosity of coating solution: 6 mPa · sec at a temperature of 20 ° C.
As shown in Table 4 (A) and FIG. 8 (A), the coating amount on the non-woven fabric base material E1 increased as the printing pressure was increased, regardless of which coating solution was used. Further, as shown in Table 4 (B) and FIG. 8 (B), the coefficient of variation of the coating amount on the non-woven fabric base material E1 became lower and stabilized as the printing pressure was increased in any of the coating liquids.

As described above, in the present invention, the functional agent is applied while applying a printing pressure of 210 kPa or more to the coated surface (nonwoven fabric surface) of the highly compressible non-woven fabric base material 8 by using a method of transferring the coating liquid by printing pressure. Paint. As a result, it is possible to suppress fluctuations in the coating amount of the coating liquid containing the functional agent on the nonwoven fabric base material 8. Further, from the viewpoint of improving the accuracy of suppressing fluctuations in the coating amount, it is preferable to apply a printing pressure of 260 kPa or more, more preferably 315 kPa or more, and a printing pressure of 500 kPa or more is applied to the non-woven fabric base material 8. Is more preferable, and it is particularly preferable to apply a printing pressure of 700 kPa or more. As a result, regardless of the conditions of the non-woven fabric base material 8, the variation in the coating amount is more preferably suppressed and stabilized.

On the other hand, in a coating device having a width, if a high printing pressure is applied in order to suppress fluctuations in the coating amount, the coating roll (transfer cylinder 1 in FIG. 1) is bent. Therefore, it is inevitable that a coating amount distribution will occur in the width direction. In fact, when the 1900 mm width coating was performed, the coating amount distribution arranged by the deflection of the roll was generated in the width direction. In wide-width coating, it is a problem that the coating amount distribution cannot be managed in the first place before the fluctuation of the coating amount is suppressed.
On the other hand, in the present invention, the coating amount fluctuation is suppressed by applying the above-mentioned high printing pressure, and at the same time, the coating amount distribution is suppressed by performing the coating while correcting the deflection. As a result, it is possible to homogenize the coating amount of the functional agent.
Hereinafter, the application of the high printing pressure, the occurrence of the deflection, and the correction thereof will be further described with reference to the coating unit (coating apparatus) 10A shown in FIGS. 1A and 1B.

In the coating unit (coating apparatus) 10A of the present embodiment, a printing pressure of 210 kPa or more is applied to the non-woven fabric base material by pressing between the transfer cylinder 1 and the impression cylinder 2. The printing pressure is uniquely determined based on the compression characteristics of the printing substrate. Therefore, it can be regarded as the management of the pushing amount = the printing pressure management. At that time, the above-mentioned (method for measuring printing pressure) is taken into consideration.
The pushing amount between the transfer cylinder 1 and the impression cylinder 2 can be set by the methods shown in FIGS. 9A and 9B. That is, first, the transfer cylinder 1 and the impression cylinder 2 are observed from the tangential direction (the direction of the arrow V in FIGS. 9A and 9B), and the peripheral surfaces of the rolls of both are brought into contact with each other to cause light leakage. The missing reference position P is set to ± 0 (zero). A load is applied to the roll from the reference position P, and the position G is set as the peripheral surface bites into the cushion tape 12 and the coating plate 13 of the transfer cylinder 1 while being deformed. The biting position G is indicated by a positive value from the reference position P. This biting is performed by applying the pushing load of the plate cylinder 1 or the pushing load of both the plate cylinder 1 and the Anilox roll 2 toward the impression cylinder 1 with the impression cylinder 1 shaft-fixed.
The amount of pushing between the transfer cylinder 1 and the impression cylinder 2 shown in FIG. 9B is measured at the positions of the roll shaft ends of the transfer cylinder 1 and the impression cylinder 2, and is measured at the roll shaft end. It is the amount of pushing in. The pushing amount at the end of the roll shaft can be called a set pushing amount.

The set push-in amount (the set push-in amount between the transfer cylinder 1 and the impression cylinder 2 and the set push-in amount between the transfer cylinder 1 and the anilox roll 3) is the material of the transfer cylinder 1, the impression cylinder 2 and the anilox roll 3. In particular, it is appropriately determined by the methods of FIGS. 9 (A) and 9 (B) in consideration of the compression characteristics of the cushion tape 12 and the coating plate 13 of the transfer cylinder 1. The amount of pushing between the anilox roll 3 and the transfer cylinder 1 can be measured by the same method in place of the impression cylinder 2 of FIGS. 9A and 9B in place of the anilox roll 3.

In the present embodiment, the set pushing amount performed by arranging the transfer cylinder 1 and the impression cylinder 2 at the biting position G generates a pushing load according to the set pushing amount. For example, as shown in FIG. 10, at the end of the roll shaft of the transfer cylinder 1, a pressing load W1 is generated according to the set pressing amount of the transfer cylinder 1 with respect to the impression cylinder 2. Further, in addition to the load W1, a pushing load W3 is generated at the end of the roll shaft of the anilox roll 3 according to the set pushing amount of the anilox roll 3 with respect to the transfer cylinder 1. The indentation loads W1 and W3 are calculated assuming that the indentation directions of the transfer cylinder 1 and the anilox roll 3 with respect to the impression cylinder 2 are coaxial and horizontal. Specifically, the impression cylinder 2 is fixed to the shaft, a load is applied to the bearing centers (support points) 91A and 91B at both ends of the transfer cylinder 1 and the Anilox roll 3, respectively, and the entire frame length L (of each roll) is applied. Push in the direction of the impression cylinder 2 (between the bearing centers). This pushing load is performed by positioning control by a servomotor and a ball screw (not shown), and can be calculated based on the following equation (1) assuming that there is no mechanical loss. Specifically, the indentation load W1 of the transfer cylinder 1 is the motor rated torque of the servomotor connected to the transfer cylinder 1 (the total value if there is a motor that imparts independent indentation to both ends of the roll). It can be calculated based on the following equation (1) based on the load factor of the servo amplifier of the servo motor (the average value if there is a motor that applies independent pushing to both ends of the roll) and the lead of the ball screw. Similarly, the indentation load W3 of the anilox roll 3 is the motor rated torque of the servomotor connected to the anilox roll 3 (the total value if there is a motor that imparts independent indentation to both ends of the roll), and the servomotor. It can be calculated based on the following equation (1) based on the load factor of the servo amplifier (the average value if there is a motor that applies independent pushing to both ends of the roll) and the lead of the ball screw.

In the present embodiment, in the coating process of the coating unit 10A, the set pressing amount at the end of the roll shaft is controlled, and the deflection of the transfer cylinder 1 and the impression cylinder 2 at the time of pressing is corrected. As a result, the difference in the pushing amount between the coating end portions 131A and 131B and the coating center portion 132 in the roll axial direction X is suppressed. As shown in FIG. 10, the coating end portions 131A and 131B and the coating central portion 132 indicate the positions of the coating plates 13 constituting the surface of the transfer cylinder 1.
As shown in FIG. 10, the non-woven fabric base material 8 between the impression cylinder 2 and the transfer cylinder 1 is pressed by the pressing load W1 + W3 according to the set pressing amount. The load W1 of the transfer cylinder 1 and the load W3 of the anilox roll 3 are applied to the impression cylinder 1, and the same load stress is applied from the impression cylinder 2. However, when a high indentation corresponding to a printing pressure of 210 kPa or more is applied at the end of the roll shaft, as shown in FIG. 11, a deflection having a distribution in the roll axis direction X of the transfer cylinder 1, that is, a distribution of the indentation amount occurs. Sometimes. In this case, the load is not evenly applied in the roll axis direction of the transfer cylinder 1. Specifically, the transfer cylinder 1 and the impression cylinder 2 are bent in the vicinity of the coating center portion 132 in the coating width (plate width) M, and the load is lower than that of the coating end portions 131A and 131B. Therefore, the pushing amount may be insufficient. That is, due to the above deflection, the distance (K1) between the cylinder body 11 of the coating central portion 132 and the impression cylinder 2 is larger than the distance (K2) between the cylinder body 11 of the coating ends 131A and 131B and the impression cylinder 2. May open wide (K1> K2). The pushing amount in the bent state is referred to as an actual pushing amount with respect to the set pushing amount (set value at the shaft end) based on FIGS. 9A and 9B described above.
This actual pushing amount differs between the coating end portions 131A and 131B and the coating central portion 132. At the coated end portions 131A and 131B, a pressing amount close to a desired value can be applied to the non-woven fabric base material 8 to generate a pressing load W1 + W3 corresponding to a desired printing pressure. However, in the coating central portion 132, the pushing load W1 + W3 is not transmitted as in the coating end portions 131A and 131B because the deflection between the cylinder body 11 of the transfer cylinder 1 and the impression cylinder 2 is large. Therefore, the impression cylinder 2 does not sufficiently bite into the coating plate 13 and the cushion tape 12, and the desired printing pressure cannot be applied to the non-woven fabric base material 8. Such a phenomenon is more likely to occur as the frame length L, particularly the coating width (plate width) M becomes longer. In the actual method for producing a non-woven fabric, a non-woven fabric having a coating width (plate width) of several meters (for example, 2 m or 3 m) is used. Therefore, the deflection phenomenon cannot be overlooked from the viewpoint of achieving homogenization of the coating amount of the functional agent in the coating process in which the pressing is larger than the kiss touch.

For example, as shown in FIGS. 12A and 12B, this phenomenon is also observed in an example in which a coating liquid is applied to an air-through non-woven fabric with a coating width (plate width) M of 1900 mm. Regardless of the set pushing amount (pushing amount at the end of the roll shaft) between the transfer cylinder 1 and the impression cylinder 2, the actual pushing amount between the transfer cylinder 1 and the impression cylinder 2 is the coating end. In 131A and 131B, it is larger than the coating central portion 132, and the coating amount also changes accordingly. That is, it can be seen that as the coating width (plate width) increases, the coating amount distribution in the width direction of the nonwoven fabric base material 8 occurs.
This result is caused by the fact that the printing pressure applied to the non-woven fabric base material 8 by pressing the transfer cylinder 1 and the impression cylinder 2 differs in the width direction. Therefore, by correcting the above-mentioned deflection, the difference in the pressing amount in the roll axial direction X is suppressed, and the printing pressure on the non-woven fabric base material 8 is equalized. As a result, the distribution of the coating amount in the width direction of the nonwoven fabric base material 8 can be suppressed. Further, as shown in Table 1 and FIG. 5 described above, there is a feature that the coating amount increases as the printing pressure is increased. Based on this feature, by increasing the printing pressure while correcting the deflection, it is possible to realize a coating with a larger coating amount while suppressing the coating amount distribution. That is, even if the coating amount is increased, the coating amount can be homogenized (variation in the coating amount and suppression of the coating amount distribution).

The graphs shown in FIGS. 12 (A) and 12 (B) above are the results obtained under the following conditions.
(I) Base material conditions An air-through non-woven fabric base material (roll raw fabric) having a basis weight of 18 g / m ² using a core-sheath type composite fiber (core: polyethylene terephthalate resin fiber, sheath: polyethylene resin fiber) having a fineness of 1.3 dtex, CD width of non-woven fabric base material: 2000 mm
(Ii) Coating liquid Polyether-modified silicone "KF-6015"
(Iii) Device conditions Set pushing amount between the transfer cylinder 1 and the impression cylinder 2: 50 μm, 150 μm, 250 μm, 350 μm, 450 μm
Set push-in amount between transfer cylinder 1 and Anilox roll 3: 250 μm
Coating width (plate width) of transfer cylinder 1 M: 1900 mm
Coating speed: 76m / min
Tension applied to the base non-woven fabric 8: 25 N / m
Cushion tape 12: "Tesa softprint 52222PV1" (trade name, manufactured by Tesa Tape Co., Ltd., thickness 0.5 mm)
Coating plate 13: "FLEXCEL NX-H" (trade name, manufactured by Kodak, thickness 1.7 mm, shore A hardness 62 °)
Anilox Roll 3: Honeycomb 700Lpi (3.5cc / m ² )
Frame length L of each roll, roll outer diameter and roll inner diameter: Table 5

Further, the graph shown in FIG. 12 (C) shows a transfer cylinder when the set pushing amount of Anilox Roll 3 is set to 100 μm, 250 μm, 350 μm, and 450 μm under the above conditions of FIGS. 12 (A) and 12 (B). The relationship between the actual pushing amount and the coating amount between 1 and the impression cylinder 2 is shown. Here, the deflection is calculated on the assumption that an evenly distributed load is applied with a plate width of 1900 mm, and the coating amount distribution in the width direction of the non-woven fabric base material 8 is determined by the actual pressing amount of the transfer cylinder 1 in consideration of the deflection. The relationship with the coating amount was shown. From this, it can be seen that the coating amount distribution in the width direction can be reduced by reducing the deflection.

The above calculation of the amount of deflection is performed according to the calculation of the deflection of the beam by the moment of inertia of area, assuming that the transfer cylinder 1, the impression cylinder 2, and the anilox roll 3 are simple support beams at both ends that receive a partially evenly distributed load. In the calculation, the indentation load W1 + W3, the frame length L, the roll outer diameter and the roll inner diameter, and the longitudinal elastic modulus (Young's modulus) of the cylinder body 11, the impression cylinder 2 and the anilox roll 3 of the transfer cylinder 1 are taken into consideration. The indentation load W1 + W3 can be calculated based on the above equation (1). In the above calculation, the roll shape is approximated to the pipe shape in which the outer diameter is the roll outer diameter, the inner diameter is the roll inner diameter, and the length is the frame length L, and further, the roll shape is evenly distributed by the coating width (plate width) M. It is considered that a load is applied.
In the deflection correction, first, the amount of deflection is calculated. Next, the deflection is corrected so as to reduce the gap distribution between the impression cylinder 2 and the transfer cylinder 1 due to the deflection. That is, the difference (K1-K2) between the distance (K1) between the cylinder body 11 of the coating center 132 and the impression cylinder 2 and the distance (K2) between the cylinder body 11 of the coating ends 131A and 131B and the impression cylinder 2 ) Is reduced so that the deflection is corrected.

(Measuring method of coating amount distribution in the width direction)
The distribution of the coating amount in the width direction can be measured with respect to the non-woven fabric sampled from an arbitrary position in the width direction (measurement method of the coefficient of variation of the coating amount).

Various correction mechanisms can be mentioned as the correction mechanism for realizing this. Among them, it is preferable to adopt at least one method selected from the deflection correction roll method, the roll crossing method, the crown roll method, and the thermal expansion correction method.

In the deflection correction roll method, as shown in FIG. 13, the deflection correction roll 6 is installed on the impression cylinder 2, and the correction indentation load W6 is applied in the direction facing the indentation load W1 + W3. Specifically, the deflection correction roll 6 is installed at a position corresponding to the coating central portion 132 on the side of the impression cylinder 2 opposite to the transfer cylinder 1. The deflection correction roll 6 applies a correction pushing load W6 in the direction from the impression cylinder 2 side toward the transfer cylinder 1 and the anilox roll 3 to correct the deflection in the coating central portion 132. As a result, the pushing amount between the transfer cylinder 1 and the impression cylinder 2 at the coating central portion 132 is restored, the difference between the pushing amount at the coating end portions 131A and 131B is suppressed, and the pushing amount is controlled to approach zero.

In the roll crossing method, one of the transfer cylinders 1 and the impression cylinder 2 is slightly rotated about a line connecting the centers. In the crown roll method, for at least one of the transfer cylinder 1 and the impression cylinder 2, the roll diameter near the coating center portion 132 is made larger than the roll diameter near the coating end portions 131A and 131B. Further, in the thermal expansion correction method, a heat medium is passed through the inside of the cylinder for either one of the transfer cylinder 1 and the small amount of the impression cylinder 2, and the amount of heat generated in the vicinity of the coating central portion 132 is measured at the coating end portions 131A and 131B. Make it larger than the amount of heat generated in the vicinity.
As a result, a desired pushing amount is surely generated at the coating central portion 132, the difference between the pushing amount at the coating end portions 131A and 131B is suppressed, and the pushing amount is controlled to approach zero.

In the present embodiment, as described above, the amount of coating in the width direction with respect to the base non-woven fabric 8 is made by minimizing the difference in the amount of pushing between the coating end portions 131A and 131B and the coating central portion 132. The distribution can be suppressed. From this point of view, the gap distribution between the impression cylinder 2 and the transfer cylinder 1, that is, the distance (K1) between the cylinder body 11 of the coating central portion 132 and the impression cylinder 2, and the cylinder bodies of the coating ends 131A and 131B. The difference (K1-K2) between the distance 11 and the impression cylinder 2 (K2) is preferably 50 μm or less, more preferably 35 μm or less, and further preferably 25 μm or less.

As described above, in the present embodiment, by correcting the high printing pressure of 210 kPa or more and the deflection, it is possible to homogenize the coating amount of the functional agent on the non-woven fabric base material 8 having high compression characteristics (suppression of coating amount fluctuation and It is possible to simultaneously suppress the occurrence of coating amount distribution in the coating width direction).

In the present invention, the pushing amount is appropriately controlled by the transfer cylinder 1 and the impression cylinder 2 without being limited to the flexographic coating method shown in FIG. 1, and the functional agent is uniformly applied to the non-woven fabric base material 8. Anything that can be worked on can be adopted as appropriate. For example, as the transfer cylinder 1, a plate cylinder provided with an intaglio plate, a planographic plate, or a stencil coating plate may be used instead of the letterpress plate. Further, a blanket cylinder may be interposed between the plate cylinder and the impression cylinder, and this blanket cylinder may be used as the transfer cylinder 1.

As another embodiment described above, a coating unit 10B of a direct gravure coating method as shown in FIG. 14 can be mentioned. In the coating unit 10B, the plate cylinder (gravure cylinder) provided with the intaglio is the transfer cylinder 1. In this case, the transfer cylinder 1 rotates so that the peripheral surface is immersed in the coating liquid of the coating liquid chamber 4, and scoops and holds the coating liquid. The transfer cylinder 1 holding the coating liquid rotates as it is, comes into contact with the impression cylinder 1 with the non-woven fabric base material 8 sandwiched between them, and applies the coating liquid while applying a desired push to the non-woven fabric base material 8.

Also in these various embodiments, similarly to the embodiment shown in FIG. 1, the printing pressure between the transfer cylinder 1 and the impression cylinder 2 is suitably controlled, and the functional agent is homogeneously applied to the surface of the non-woven fabric base material. It is possible to accurately manufacture a non-woven fabric coated with. Further, the coating amount can be suitably controlled, and the required amount of coating liquid can be uniformly coated on the surface of the nonwoven fabric base material 8.

Further, in the method for producing a non-woven fabric of the present invention, the tension applied to the non-woven fabric base material 8 in the transport direction, that is, the tension applied in the MD direction during transport of the non-woven fabric base material is applied to the coating process (coating unit). In 10A), it is preferably 100 N / m or less, more preferably 30 N / m or less, and further preferably 5 N / m or less. As a result, the occurrence of necking in the non-woven fabric base material 8 can be suppressed, the printing pressure can be uniformly received, and the accuracy of homogenizing the coating amount of the functional agent can be further improved.

1 Transfer cylinder 2 Impression cylinder 3 Anilox roll 4 Coating chamber 6 Deflection correction roll 8 Non-woven fabric base material 10A, 10B Coating part 11 (Transfer cylinder) Cylinder body 12 (Transfer cylinder) Cushion tape 13 (Transfer cylinder) coating Construction plate 14 (coating plate) convex portions 131A, 131B (transfer cylinder) coating end portion 132 (transfer cylinder) coating center portion P Reference position H Separation position G Biting position

Claims (9)

A non-woven fabric base material is sandwiched between the roll peripheral surface of the transfer cylinder for transferring the coating liquid containing the functional agent and the roll peripheral surface of the impression cylinder for applying the printing pressure, and the functional agent is applied to the surface of the non-woven fabric base material. A coating step is provided, in which a printing pressure of 210 kPa or more is applied to the non-woven fabric base material, and the deflection of the transfer cylinder and the impression cylinder at the time of pushing is corrected, and coating is performed in the roll axis direction. A method for manufacturing non-woven fabrics that suppresses the difference in the amount of pushing between the work end and the center of coating. The method for producing a non-woven fabric according to claim 1, wherein the coating is a flexographic coating method or a direct gravure coating method. The method for producing a non-woven fabric according to claim 1 or 2, wherein at least one method selected from a deflection correction roll method, a roll crossing method, a crown roll method and a thermal expansion correction method is used as the correction. The method for producing a nonwoven fabric according to any one of claims 1 to 3, wherein the gap distribution between the impression cylinder and the transfer cylinder in the roll axis direction is controlled to 50 μm or less. The method for producing a non-woven fabric according to any one of claims 1 to 6, wherein the tension applied to the non-woven fabric substrate in the transport direction is 100 N / m or less in the coating step. A non-woven fabric base material is sandwiched between the peripheral surface of the roll of the transfer cylinder for transferring the coating liquid containing the functional agent and the peripheral surface of the roll of the impression cylinder for applying the printing pressure, and the functional agent is applied to the surface of the non-woven fabric base material. A coating portion to be coated is provided, and the coating portion applies a printing pressure of 210 kPa or more to the non-woven fabric base material, and by a mechanism for correcting the deflection of the transfer cylinder and the impression cylinder at the time of pushing. A non-woven fabric manufacturing apparatus that performs the coating by suppressing the difference in the pushing amount between the coating end portion and the coating center portion in the roll axis direction by the correction mechanism. The non-woven fabric manufacturing apparatus according to claim 6, wherein the coating is a flexographic coating method or a direct gravure coating method. The non-woven fabric manufacturing apparatus according to claim 6 or 7, wherein the correction mechanism uses at least one method selected from a deflection correction roll method, a roll crossing method, a crown roll method, and a thermal expansion correction method. The non-woven fabric manufacturing apparatus according to any one of claims 6 to 8, wherein the coating unit controls the gap distribution between the impression cylinder and the transfer cylinder in the roll axis direction to 50 μm or less.