JP6171075B1 - Laminated sheet and manufacturing method thereof - Google Patents

Abstract

The present invention provides a laminated sheet having excellent breathability over the entire surface of the laminated sheet. An adhesive sheet 11 positioned in the middle and nonwoven fabrics 12 and 12 positioned on the front and back are laminated and integrated, and the laminated sheet has at least three layers, and the laminated sheet has an embossed uneven portion 15. Further, the overlapping sheets are fitted and joined only at the embossed uneven portion 15. Moreover, the height of the convex part of the said embossing uneven | corrugated | grooved part protrudes from the back surface of a lamination sheet, It is characterized by the above-mentioned. Furthermore, the depth of the recessed part of the said embossed uneven | corrugated | grooved part is larger than the thickness of a lamination sheet, It is characterized by the above-mentioned. And the outer periphery of the bottom face of the recessed part of the said embossed uneven | corrugated | grooved part has the strong crimping | compression-bonding part strongly crimped | bonded to the ring shape. [Selection] Figure 1

Description

The present invention relates to a laminated sheet suitable for filter applications having excellent air permeability and a method for producing the same.

Conventionally, laminated sheets using various nonwoven fabrics have been proposed as materials for air filters and liquid filters for removing dust.

However, a laminated sheet using a chemical adhesive may be eluted when immersed in a liquid (oil or the like) and cannot be used for a filter used for filtering food. In recent years, there is an example in which a thermocompression type long fiber nonwoven fabric is used as a material for a filter by embossing.

For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-268664), a laminate formed by laminating and bonding two nonwoven fabrics by embossing using an embossing roll having a plurality of convex portions formed on the roll surface. A nonwoven fabric is disclosed.
JP 2003-268664 A

However, in the laminated sheet as in Patent Document 1, in the embossed recesses in the joining region, the resin fibers of each nonwoven fabric sheet are melted to close the mesh, and the air permeability in the embossed portions (recesses) is blocked.
Therefore, the air permeability in the concave portion of the laminated sheet is blocked, so that the air permeability of the laminated sheet as a whole deteriorates.
Therefore, in view of the above-described problems of the prior art, the present invention intends to provide a laminated sheet having excellent air permeability as the entire surface of the laminated sheet.

The present invention employs the following means in order to solve such problems.
That is,
(1) The laminated sheet of the present invention is an at least three-layer laminated sheet 10 in which an adhesive sheet 11 located in the middle and nonwoven fabrics 12 and 12 located on the front and back are laminated and integrated,
The laminated sheet 10 has an embossed uneven portion 15,
The overlapping sheets are fitted and joined only at the embossed irregularities,
The height h of the convex portion 15 a of the embossed concave-convex portion 15 protrudes from the back surface 10 b of the laminated sheet 10.
(2) The laminated sheet of the present invention is characterized in that, in the above (1), the depth S of the concave portion 15b of the embossed uneven portion 15 is larger than the thickness T of the laminated sheet 10.
(3) In the above (1) or (2), the laminated sheet of the present invention has a strong pressure bonding portion 15e in which the outer peripheral edge of the bottom surface 15c of the concave portion 15b of the embossed concave and convex portion 15 is strongly pressure-bonded in a ring shape. It is characterized by.
(4) In the method for producing a laminated sheet of the present invention, the laminated sheet 13 in which the adhesive sheet 11 positioned in the middle and the nonwoven fabrics 12 and 12 positioned on the front and back are stacked between the embossing roll 21 and the receiving roll 31. By passing, the embossing pin 22 formed so as to stand upright from the base surface 21a of the embossing roll 21 is pressed against the surface of the overlapping sheet 13 to form the embossed uneven portion 15 on the laminated sheet. A manufacturing method of
When the laminated sheet 10 passes between the embossing roll and its receiving roll, the tip 22a of the embossing spin 22 of the embossing roll 21 is brought into contact with the overlapping sheet 13 and embedded in the receiving roll 31 for deep drawing embossing. Then, the embossed uneven portion 15 is formed, and the adhesive sheet 11 and the nonwoven fabrics 12 and 12 are fitted in the embossed uneven portion 15.
(5) In the method for producing a laminated sheet of the present invention, in (4) above, a ring-shaped strong pressing portion 22f is provided on the outer peripheral edge of the tip portion 22a of the embossed spin 22, and the concave portion 15b of the embossed uneven portion 15 is provided. The bottom surface 15c is strongly pressure-bonded by the strong pressing portion 22f, and a ring-shaped strong pressure-bonding portion 15e is formed on the outer peripheral edge of the bottom surface 15c of the concave portion 15b.
(6) In the manufacturing method of the laminated sheet of the present invention, in the above (5), the ring-shaped strong pressing portion 22f provided on the outer peripheral edge of the tip portion 22a of the embossed spin 22 extends in the height direction of the embossed spin 22. The protruding portion 22g is provided, and the bottom surface 15c of the concave portion 15b of the embossed uneven portion 15 is strongly pressure-bonded by the protruding portion 22g, and a ring-shaped strong pressure-bonding portion 15e is provided on the outer peripheral edge of the bottom surface 15c of the concave portion 15b. It is characterized by forming.
(7) The method for producing a laminated sheet of the present invention is the base surface 21a of the embossing roll 21 when the laminated sheet 10 passes between the embossing roll 21 and the receiving roll 31 in the above (4) to (6). However, it has the gap | interval c so that it may not contact the nonwoven fabric 12 which opposes.
(8) In the manufacturing method of the laminated sheet of the present invention, in the above (4) to (7), light is irradiated from one side of the laminated sheet laminated with the embossing roll 21 and the receiving roll 31 and from the other side. The embossed uneven portion 15 formed on the laminated sheet is monitored.

The laminated sheet of the present invention is an laminated sheet 10 of at least three layers formed by laminating and integrating an adhesive sheet 11 located in the middle and nonwoven fabrics 12 and 12 located on the front and back,
Since the laminated sheet has an embossed uneven part, and the height h of the convex part 15a of the embossed uneven part 15 protrudes from the back surface 10b of the laminated sheet,
A laminated sheet suitable for a non-woven fabric for a filter having excellent breathability and excellent mechanical strength and durability can be provided.
Also, because it is laminated by forming embossed uneven parts without using chemical adhesive,
It can be applied to the field where chemical adhesives are prohibited.
For example, it can be used for filters for edible oil and for medical use.

It is the vertical cut partial enlarged view of the lamination sheet 10 which has the embossing uneven | corrugated | grooved part 15 which concerns on Embodiment 1 of this invention. It is a top view of the lamination sheet 10 which has the embossing uneven | corrugated | grooved part 15 which concerns on Embodiment 1. FIG. 1 is a schematic side view of a deep drawing embossing apparatus used for deep drawing embossing of a laminated sheet 10. FIG. It is a front view of the embossing roll 21 used in order to carry out deep drawing embossing to the lamination sheet. It is an expansion longitudinal cross-sectional view of the embossed uneven | corrugated | grooved part 15 of the lamination sheet 10 which concerns on Embodiment 2. FIG. FIG. 6 is an enlarged vertical cut sectional view of an embossed uneven portion 15 of a laminated sheet 10 according to Embodiment 3. It is an expansion longitudinal cross-sectional view of the embossed uneven | corrugated | grooved part 15 of the lamination sheet 10 which concerns on Embodiment 4. FIG. FIG. 6 is an enlarged vertical cut sectional view of an embossed uneven portion 15 of a laminated sheet 10 according to a fifth embodiment. It is the embossing uneven | corrugated | grooved part 15 of the lamination sheet which concerns on Example 1, (a) is a longitudinally cut partial enlarged view, (b) is the top view. It is the embossing recessed part which carried out the thermocompression bonding of the lamination sheet which concerns on the comparative example 1, (a) is a longitudinally-cut partial enlarged view, (b) is the top view.

<Embodiment 1>
FIG. 1 is an enlarged vertical cross-sectional view of an embossed uneven portion 15 of a laminated sheet 10 having an embossed uneven pattern according to the first embodiment.
FIG. 2 is a plan view of the laminated sheet 10 having the embossed uneven pattern according to the first embodiment.
As shown in FIGS. 1 and 2, in the laminated sheet 10 of the first embodiment, an adhesive sheet (for example, melt blown nonwoven fabric) 11 positioned in the middle and nonwoven fabrics (for example, spunbonded nonwoven fabric) 12 and 12 positioned on the front and back are laminated and integrated. The laminated sheet 10 has at least three layers, and the laminated sheet has an embossed concavo-convex portion 15, and the concave portion 15b formed on the surface of the laminated sheet has a convex portion 15a on the back surface 10b side of the laminated sheet. As overhanging.
The laminated sheet 10 according to the first embodiment is characterized in that the overlapping sheets are fitted and joined only at the embossed uneven portions. In other parts, the overlapping sheets are not joined.
In addition, the height h of the convex portion 15a protrudes from the back surface 10b of the laminated sheet 10.
Furthermore, it is preferable that the depth S of the recessed portion 15 b of the embossed uneven portion 15 is larger than the thickness T of the laminated sheet 10.
The depth S of the recessed part 15b means the distance between the bottom surface 15c of the embossed uneven part 15 and the surface 10a of the laminated sheet 10, as shown in FIG.
This is because by making the depth S of the concave portion 15b larger than the thickness T of the laminated sheet 10, the dimension of the side wall 15d of the concave portion 15b can be increased, and air can be secured from the side wall 15d to the back surface 10b of the laminated sheet 10. .

<Nonwoven fabric located on the front and back>
Next, two types of sheets constituting the laminated sheet 10 will be described.
Examples of the nonwoven fabric constituting the front and back layers of the laminated sheet 10 include a spunbond nonwoven fabric 12. For example, a molten polymer is extruded from a die, and this is sucked and stretched with a high-speed suction gas, and then collected on a moving conveyor. It is a non-woven fabric having air permeability produced by a so-called spunbond method, which is represented by a method of forming a web and further continuously forming a sheet by heat treatment, entanglement and the like.
The average fiber diameter of the fibers constituting the spunbonded nonwoven fabric is preferably in the range of 10 to 30 μm.
When the average fiber diameter is smaller than 10 μm, the air permeability of the nonwoven fabric is lowered and the rigidity of the nonwoven fabric tends to be lowered, which is not preferable. In addition, yarn breakage is likely to occur during the production of a spunbonded nonwoven fabric, which is not preferable from the viewpoint of production stability.
When the average fiber diameter is larger than 30 μm, yarn breakage is liable to occur due to poor cooling of the yarn during production of the spunbonded nonwoven fabric, which is not preferable from the viewpoint of production stability.

The spunbonded nonwoven fabric is preferably made of polyester.
Polyester nonwoven fabrics have a relatively high melting point and thus are excellent in heat resistance and also in rigidity. In addition, a polyester-type nonwoven fabric contains a polyethylene terephthalate, and what has this as a main component is preferable.
As the polyester-based nonwoven fabric, a core-sheath type spunbonded nonwoven fabric in which the core part includes polyethylene terephthalate and the sheath part includes a copolyester having a melting point lower than that of the core polymer is preferable from the viewpoint of strength and rigidity.
The core polymer is preferably composed mainly of polyethylene terephthalate.
The copolymer polyester has a melting point of 15 ° C. or more lower than that of polyethylene terephthalate contained in the core, and isophthalic acid and adipic acid are preferable as the copolymer component.
When such a core-sheath fiber is employed, the polyethylene terephthalate contained in the core component has a higher melting point than the copolymer polyester contained in the sheath component, so that it is less susceptible to damage during strong pressure bonding with the melt blown nonwoven fabric, , The rigidity tends to improve.

<Adhesive sheet 11>
Examples of the adhesive sheet 11 positioned in the middle of the laminated sheet 10 include a melt blown nonwoven fabric. The melted polymer is extruded from a base, and stretched while spraying a heated high-speed gas fluid or the like on the molten polymer, and is captured. It is a non-woven fabric having heat softening property, adhesiveness and air permeability, which is produced by a so-called melt blow method represented by a method of collecting and forming a sheet.
The average fiber diameter of the fibers constituting the meltblown nonwoven fabric 11 is preferably in the range of 1 to 8 μm.
When the average fiber diameter is smaller than 1 μm, when the polymer is stretched to form ultrafine fibers, the fibers are easily cut and a lump polymer may be mixed, which is not preferable.
Furthermore, there is a tendency that the air permeability of the nonwoven fabric is lowered, which is not preferable.
When the average fiber diameter is more than 8 μm, the fiber becomes too thick, which is not preferable because the dust collection performance tends to be lowered.

In addition, the melt blown nonwoven fabric 11 contains adhesive fibers, and by deep drawing embossing, two spunbonded nonwoven fabrics can be firmly fitted and integrated via the melt blown nonwoven fabric, which is excellent in durability. This is because a clear embossed uneven portion 15 can be formed on the laminated sheet.
The meltblown nonwoven fabric 11 also has a property of being softened and melted by heat, and has a composite fiber structure composed of a thermal adhesive component and a skeleton component having a melting point higher than that of the thermal adhesive component.
Examples of the composite form include a core-sheath composite form and a side-by-side composite form.
In view of form retention, flexibility, mechanical strength, bulkiness, and the like when embossing is performed, a core-sheath composite fiber is preferable.
Moreover, it is preferable that a thermobonding component consists of a polyolefin-type polymer with favorable softness | flexibility.
Examples of the polyolefin-based polymer include polypropylene, polyethylene, a copolymer of ethylene and propylene, or a blend thereof.
In the case of composite form fibers, the combination of the skeleton component and the thermal adhesive component (skeleton component / thermal adhesive component) includes polyester polymer / polyolefin polymer, polyamide polymer / polyolefin polymer, polypropylene / polyethylene. And a copolymer of polypropylene / ethylene and propylene.

<Unit weight>
The basis weight of the melt blown nonwoven fabric 11 or the spunbonded nonwoven fabric is preferably in the range of 5 to 300 g / m ² .
When the basis weight is less than 5 g / m ² , the strength and rigidity of the nonwoven fabric may be insufficient, which is not preferable.
When the weight per unit area exceeds 300 g / m ² , the strength and rigidity of the nonwoven fabric are sufficient, but the air permeability tends to decrease, and further, it is not preferable in terms of cost.
The basis weight here is in accordance with 5.2 of JISL 1906 (2000 edition).

In the laminated sheet 10 of the first embodiment, the lamination ratio of the spunbond nonwoven fabric 12 and the melt blown nonwoven fabric 11 is set so that the weight per unit area of the spunbond nonwoven fabric is 1 in consideration of the breathability of the laminated sheet and the fitting strength at the embossed uneven portions. In this case, the basis weight of the melt blown nonwoven fabric is preferably 20 g / m ² or more.

The laminated sheet 10 of Embodiment 1 is laminated in the order of spunbond nonwoven fabric / melt blown nonwoven fabric / spunbond nonwoven fabric, and laminated and integrated by partially forming the embossed irregularities 15 on the laminated sheet by deep drawing embossing. Yes.

The shape of the concave portion 15 to be the embossed concave / convex portion 15 in a plan view includes a circular shape, an elliptical shape, a quadrangular shape, a cross shape, a flower shape, a star shape, etc., which are scattered in a staggered pattern or a geometric pattern. Can be mentioned.

In addition, the ratio (recessed area ratio) which the recessed part 15 occupies for the whole lamination sheet 10 considers the softness | flexibility as the laminated sheet 10, the joint strength for lamination | stacking integration, etc., and about 5-50% is preferable.

The laminated sheet 10 of the first embodiment is provided with an embossed uneven portion 15 by deep drawing embossing.
This is because the embossed spin 22 formed to stand upright from the base surface 21a of the embossing roll 21 softens the adhesive component of the melt blown nonwoven fabric when pressure is applied to the overlapping sheet 13 by deep drawing embossing, A concave portion 15b is formed in the overlap sheet 13 by the tip of the emboss pin 22, and the spunbond nonwoven fabric is nested and integrated through the adhesive sheet 11, and at the same time, the embossed uneven portion 15 is formed in the laminated sheet 10. To do.
In addition, the lamination | stacking of the said spunbond nonwoven fabric / melt blown nonwoven fabric / spunbond nonwoven fabric may be a laminate of each nonwoven fabric. For example, a sheet in which a nonwoven fabric having some functionality is laminated in advance. These nonwoven fabrics can be appropriately employed depending on the application.

<Manufacturing method>
Below, the detail of the manufacturing method of the lamination sheet of Embodiment 1 is described below.
In the laminated sheet manufacturing method of the first embodiment, between the embossing roll 21 and the receiving roll 31, the overlapping sheet 13 in which the adhesive sheet 11 positioned in the middle and the nonwoven fabrics 12 and 12 positioned on the front and back are passed is passed. With the manufacturing method of the laminated sheet 10, the embossed spin 22 formed so as to stand from the base surface 21 a of the embossing roll 21 is pressed against the surface of the overlapping sheet 13 to form an embossed uneven portion on the laminated sheet. Thus, when the laminated sheet 10 passes between the embossing roll 21 and the receiving roll 31, the tip 22a of the embossing spin 22 of the embossing roll 21 is brought into contact with the laminated sheet and embedded in the receiving roll 31. At the same time, an embossed uneven portion is formed by deep drawing embossing, and the adhesive sheet 11 is formed in the embossed uneven portion 15. Characterized in that fitting the non-woven fabric 12 and 12 nested state.
As a result, the three-layer sheet is mechanically bonded to the embossed uneven portion 15 without using a chemical adhesive.

In FIG. 3, an example of the embossing apparatus used in order to perform deep drawing embossing in manufacture of the lamination sheet 10 of Embodiment 1 is shown.
As can be seen from FIG. 3, the deep drawing embossing apparatus is composed of an embossing roll 21 and a smooth receiving roll 31, and the temperature of the embossing spin 22 of the embossing roll 21 softens the thermal adhesive component of the melt blown nonwoven fabric 11. It is preferable to set the temperature at a level.
This temperature is appropriately set according to the linear pressure, the processing speed, and the basis weight of the spunbond nonwoven fabric of the surface layer.
For example, when Tm is the melting point of the heat-bonding component of the melt blown nonwoven fabric 11 (the softening point is regarded as the melting point for those having no clear melting point), the range is (Tm−15) ° C. to (Tm + 10) ° C. Is preferred.
If this temperature is too high, the bottom surface 15c of the embossed concavo-convex portion composed of three layers of spunbond nonwoven fabric / melt blown nonwoven fabric 11 / spunbond nonwoven fabric is brought into close contact during deep drawing embossing, and air permeability is impaired.
On the other hand, when this temperature is too low, the bonding between the three sheet material layers at the embossed uneven portion is weak, and the laminated sheet may be peeled off.
These temperatures can be set within a predetermined range via heaters provided on the embossing roll 21 and the receiving roll 31.
Moreover, when heating the surface of the receiving roll 31, another roll can be provided in the outer side and the heat from the separate roll can also be received by transfer.
In addition, the deep drawing embossing apparatus provided with the embossing roll 21 and the receiving roll 31 has a supply roll for supplying each sheet | seat material between these rolls, and a winding roll for winding up a lamination sheet. The tension applied to the laminated sheet during deep drawing embossing can be controlled.

Moreover, in the said manufacturing method, when the lamination sheet 10 passes between the embossing roll 21 and the receiving roll 31, it is preferable that the base surface 21a of the embossing roll 21 does not contact the nonwoven fabric 12 which opposes.
For example, as shown in FIG. 3, when the laminated sheet 10 passes between the embossing roll 21 and the receiving roll 31, a gap C is secured between the embossing roll 21 and the base surface 21 a, and the back surface of the laminated sheet 10. It is important that 10b does not come into contact with the base surface 21a of the embossing roll 21 that is facing.
When the base surface 21a of the heated embossing roll 21 comes into contact with the spunbond nonwoven fabric 12, the surface of the spunbond nonwoven fabric 12 adheres and adheres to the base surface 21a of the embossing roll 21, and the laminated sheet may be peeled off. Because.

Furthermore, in the said manufacturing method, light can be irradiated from the one side of the lamination sheet laminated | stacked with the embossing roll 21 and its receiving roll 31, and the embossing uneven | corrugated | grooved part 15 formed in the lamination sheet from the other side can also be monitored. .
That is, when the bottom surface 15c of the embossed concavo-convex portion 15 is strongly pressure-bonded, it becomes black and the amount of transmitted irradiation light decreases, so that the joining state of the bottom surface 15c of the embossed concavo-convex portion 15 can also be monitored.
In addition, the transmitted irradiation light of the laminated sheet can detect an image of a mirror or a camera installed below the laminated sheet.
Moreover, it can also monitor by an operator's direct visual confirmation.
When an abnormality is detected in the amount of transmitted irradiation light, the temperature adjustment of the embossing roll 21, the linear pressure of the upper and lower rolls, the processing speed, etc. are adjusted as appropriate to change the manufacturing conditions.

In FIG. 4, the front view of the embossing roll 21 used in order to form the embossing uneven | corrugated | grooved part 15 in manufacture of the lamination sheet 10 of Embodiment 1 is shown.
The embossing roll 21 is made of, for example, a metal whose surface is plated and has a heater inside the roll.
The roll diameter (A) to be the base surface 21a is 100 mm to 700 mm, and the substantially embossed spins 22 standing on the base surface 21a at a predetermined height from the base surface 21a have a predetermined distance from each other. Are arranged.
The diameter and height of the emboss pin 22 are appropriately selected depending on the thickness of the laminated sheet and the specifications of the embossed uneven portion 15.
Examples of the metal material applied to the embossing roll 21 include steel, cast iron, copper, aluminum alloy, and stainless steel. Among these, steel and cast iron are preferably employed for reasons such as excellent formation of convex portions in the roll etching method.
For example, the embossing roll can be manufactured by coating the cylindrical roll surface with a photosensitive film, exposing it, and then immersing it in an etching solution to dissolve unnecessary parts (parts other than embossed pins) for a long time. By doing so, the substantially cylindrical embossed spin 22 can be formed upright from the base surface 21 a of the embossing roll 21.
Further, the embossed spin 22 can be formed upright on the base surface 21 a of the embossing roll 21 by a processing method such as laser or cutting.

<Receiving roll 31>
The receiving roll 31 is preferably a smooth cylindrical body that is disposed at a predetermined interval facing the embossing roll 21 and at least the surface thereof has an elastic body that is deformed by pressing the embossed spin 22 during deep drawing embossing. it can.
Such an elastic body is employed from the viewpoints of preventing adhesion of the laminated sheet on the bottom surface 15c of the embossed concavo-convex portion and suppressing pinhole generation during deep drawing embossing.
As the material of the elastic body, a material that is deformed by pressing the emboss pin 22 such as a hard synthetic resin such as silicon (also referred to as silicone) rubber or polyimide, or a heat resistant rubber can be applied. From the viewpoint of heat resistance, a receiving roll 31 made of silicon rubber is suitable.
In addition, as shown in FIG. 3, when the embossing roll 22 rotates, the corner (edge) of the embossed spin 22 is in an acute angle with the laminated sheet 10. In particular, pinholes are easily generated.
Therefore, the receiving roll 31 is preferably made of an elastic material such as silicon or rubber that is easily deformed by pressing the embossed spin 22.

In the deep drawing embossing performed by the embossing roll 21 and the receiving roll 31, both the embossing roll 21 having the embossed spin 22 and the receiving roll 31 having a smooth surface are rotated while being pressed with a predetermined pressure. (Press the receiving roll (lower roll) with the embossing roll (upper roll)).
Then, when the overlapping sheet 13 is passed through the gap between the embossing roll 21 and the receiving roll 31, the tip of the emboss pin 22 is brought into contact with the laminated sheet and pushed into the receiving roll 31.
Thereby, the overlap sheet 13 is deep-drawn embossed to form an embossed uneven portion 15, and in the embossed uneven portion 15, the adhesive sheet 11 and the nonwoven fabrics 12 and 12 are nested and mechanically fitted, The stacked sheet 13 is referred to as a stacked sheet 10.

<Pressing force between upper and lower rolls>
The pressing force between the upper and lower rolls relative to the 25 kg / cm ^2, the preferred range is 15~35kg / cm ^2.
If it is less than 15 kg / cm ^2, it can not be formed excellent embossing uneven portion be deep drawing embossed push the embossing pins in the receptacle roll 31 of silicone rubber, in a laminated sheet exceeds 35 kg / cm ² Since the possibility that a pinhole is formed increases, it is not preferable.

<Temperature of embossing roll 21>
The temperature of the embossing spin 22 of the embossing roll 21 is preferably 5 ° C to 50 ° C with a temperature difference from the melting point of the spunbond nonwoven fabric.
When the temperature difference from the melting point of the polymer existing on the fiber surface of the spunbond nonwoven fabric is less than 5 ° C. (the temperature of the embossed spin 22 is too high), the polymer melts severely, and the sheet is taken onto the embossing roll 21 ( Melting adhesion), roll contamination occurs, the laminated sheet becomes hard, and roll winding frequently occurs, so that stable production becomes impossible.
Further, when the temperature difference from the melting point of the polymer existing on the fiber surface of the spunbond nonwoven fabric exceeds 50 ° C. (the temperature of the embossed spin 22 is too low), the polymer is not sufficiently fused, and the embossed uneven portion The nonwoven fabric integrated at 15 may cause poor bonding.
In order to form the embossed uneven portion 15 with good bonding, it is preferable that the temperature of the embossed spin 22 (for example, 155 ° C.)> The surface temperature of the receiving roll 31 (for example, 135 ° C.).

<Area ratio of embossed irregularities>
The area ratio of the embossed uneven portion in plan view when the melt blown nonwoven fabric and the spunbond nonwoven fabric are integrated by the embossed uneven portion is preferably 1 to 50% with respect to the total area of the laminated sheet.
When the area ratio of the embossed irregularities is less than 1%, the melt-blown nonwoven fabric and the spunbond nonwoven fabric are not sufficiently integrated (so-called striking effect or wedge effect), and the layers of the nonwoven fabric are peeled off or strong. It tends to be low, which is not preferable.
When the pressure-bonding area ratio of the strong pressure-bonding portion exceeds 50%, the air permeability tends to decrease, which is not preferable.
The area ratio of the embossed irregularities is the ratio of the area of the fitted portion on the contact surface where the meltblown nonwoven fabric and the spunbond nonwoven fabric are integrated to the planar view area of the laminated sheet.

In addition, at the time of deep drawing embossing, it is preferable not to contact the base surface 21a of the embossing roll 21 with the spunbonded nonwoven fabric, and to ensure a predetermined distance C from the base surface 21a of the embossing roll 21 ( (See FIG. 3).
This is because when the base surface 21 a of the heated embossing roll 21 comes into contact with the surface of the spunbond nonwoven fabric 12, there is a possibility that the spunbond nonwoven fabric 12 is thermally bonded.

<Embodiment 2>
FIG. 5 is an enlarged longitudinal sectional view of the embossed uneven portion 15 of the laminated sheet 10 according to the second embodiment, in which the outer peripheral edge of the bottom surface 15c of the recessed portion 15b of the embossed uneven portion 15 is strongly pressed into a ring shape. Although it is different in that it has a wearing portion 15e, it is the same as the laminated sheet 10 of Embodiment 1 in other points.
That is, in the second embodiment, the embossed uneven portion 15 strongly presses the bottom surface 15c of the recessed portion 15b of the embossed uneven portion 15 by the tip portion 22a of the embossed spin 22 provided with the ring-shaped strong pressing portion 22f on the outer peripheral edge thereof. Since the portion 22f is strongly pressure-bonded, a ring-shaped strong pressure-bonding portion 15e is formed on the outer peripheral edge of the bottom surface 15c of the recess 15b.
For this reason, the fitting intensity | strength of the lamination sheet in the embossing uneven | corrugated | grooved part 15 can be improved.
Note that, as can be seen from FIG. 5, the portion (center) other than the outer peripheral edge of the tip portion 22a of the embossed spin 22 is a surface having a rough surface roughness (a jagged state 22e).
For this reason, since the sheet surface is not strongly pressed at the central jagged state 22e portion of the bottom surface 15c of the recess 15b, the mesh of the nonwoven fabric is not blocked and air permeability at the bottom surface 15c can be ensured.

<Embodiment 3>
FIG. 6 is an enlarged longitudinal sectional view of the embossed uneven portion 15 of the laminated sheet 10 according to the third embodiment, which differs in that the side wall of the embossed uneven portion 15 is in an inclined state having a taper. This is the same as the laminated sheet 10 of the second embodiment.
That is, in the third embodiment, the embossed uneven portion 15 includes the inclined portion 22d in which the side wall of the embossed spin 22 has a taper, and pinholes at the bottom surface 15c due to the edge of the embossed spin 22 can be prevented. .

<Embodiment 4>
FIG. 7 is an enlarged longitudinal sectional view of the embossed uneven portion 15 of the laminated sheet 10 according to the fourth embodiment. The outer diameter of the bottom portion 15c of the embossed uneven portion 15 is larger than the inner diameter of the mouth portion 15f of the embossed uneven portion 15. However, it is the same as the laminated sheet 10 of the second embodiment in other points.
That is, in Embodiment 4, the outer diameter of the tip 22a of the embossed spin 22 is formed larger than the root, and the embossed uneven portion 15 deep-drawn embossed with such an embossed spin 22 has its bottom 15c. The outer diameter of the embossed uneven portion 15 is formed larger than the inner diameter of the mouth portion 15f.
For this reason, the mechanical fitting strength of the laminated sheet in which the embossed concavo-convex portion 15 is nested can be improved, and a laminated sheet that is more difficult to isolate can be obtained.
Moreover, since the ventilation area in the recessed part 22 can be enlarged, air permeability can also be improved.

<Embodiment 5>
FIG. 8 is an enlarged vertical cross-sectional view of the embossed uneven portion 15 of the laminated sheet 10 according to the fifth embodiment, and a ring-shaped strong press-bonded portion formed on the outer peripheral edge of the bottom surface 15 c of the recessed portion 15 b of the embossed uneven portion 15. 15e is different in that it has stronger bonding strength, but is otherwise the same as the laminated sheet 10 of the second embodiment.
That is, in the fifth embodiment, the ring-shaped strong pressing portion 22f provided on the outer peripheral edge of the tip portion 22a of the embossed spin 22 includes the protruding portion 22g extending in the height direction of the embossed spin 22, and the embossed spin The bottom surface 15c of the concave portion 15b of the concavo-convex portion 15 is strongly pressure-bonded by the protruding portion 22g, and a ring-shaped strong pressure-bonding portion 15e is formed on the outer peripheral edge of the bottom surface 15c of the concave portion 15b.
Thereby, the fitting intensity | strength of the lamination sheet in the bottom part 15c of the embossing uneven | corrugated | grooved part 15 can further be improved, and it can be set as the lamination sheet which is harder to isolate.

<Breathability evaluation of laminated sheet>
The breathability of the laminated sheet of the present invention was evaluated as follows.
The air permeability test was conducted using a Frazier type air permeability tester based on JIS L1096 “General Textile Test Method”.
The Frazier method is a test method that is commonly used as a breathability test for fabrics, non-woven fabrics, filters, etc., and is a test that evaluates breathability by measuring the amount of air that passes through gaps in the fabric tissue. is there.
The air permeability measured by this apparatus represents the amount of air passing through the test piece under a certain differential pressure (pressure difference when air passes through the test surface) in unit area and unit time (cm ³ / cm ² / sec).
Attach the test piece (laminated sheet) to the Frazier-type air permeability tester, adjust the air suction pump so that the tilt-type barometer shows a pressure of 1.27 cm of water with an adjustable resistor, and the vertical pressure at that time From the pressure indicated by the meter and the type of air hole (air orifice) used, the amount of air passing through the test piece is determined by a conversion table attached to the tester.
The measurement was performed 5 times and expressed as an average value (expressed to one decimal place).
The conversion table attached to the tester shows the flow rate according to the type of orifice and the differential pressure.

<Test conditions for air permeability evaluation>
The air permeability was evaluated under the following conditions.
Test equipment: Toyo Seiki Seisakusho, model number T-13
Orifice: 2 mm
Pressure: Air permeability of a 5-inch test piece Unit: cm ³ / cm ² / sec
Test location: Shizuoka Prefecture Hamamatsu Industrial Laboratory Aeration test results are shown in Table 1 as examples and comparative examples.

<Application>
The use of the laminated sheet of the present invention is not limited in any way, but it is preferably used as a filter for filtering water, air, oil, blood, etc. because of its excellent mechanical strength and durability, and excellent breathability. can do.
For example, as a pleated cylindrical unit, a bag filter such as a dust collector, a liquid filter such as an electric discharge machine, an intake filter used to clean intake air such as a gas turbine or an automobile engine, etc. A laminated sheet is preferably applicable.

The present invention will be specifically described below based on examples.
In addition, each characteristic value of an above-described nonwoven fabric and each characteristic value in the following Example are measured by the above-mentioned test method.

<Example 1>
The laminated sheet of Example 1 was manufactured under the following conditions.
(1) Manufacturing conditions Diameter of embossing pin 22 of embossing roll 21: 1.5 mm
The embossed spin pins were arranged so that the ratio of the recesses per unit area of the laminated sheet (in plan view) was 10%.
<Roll temperature>
Embossing roll 21 (material is iron): 157 ° C
Receiving roll 31 (material is silicone resin): 140 ° C
The hardness of the receiving roll was 65 °. The hardness is measured at room temperature based on JIS K 6301 (JIS A TYPE): TECKLOCK Co., Ltd. (model number GS-706N is used, and the same applies hereinafter)
Laminated sheet conveyance speed: 5 m / min. Pressing force between upper and lower rolls: 25 kg / cm ² (preferable range: 15 to 35 kg / cm ² )
(2) Laminated sheet produced A laminated sheet produced under these conditions is shown in FIG.
FIG. 9 is an enlarged view of the embossed uneven portion 15 of the laminated sheet according to the example, (a) is a cut sectional view, and (b) is a plan view.
As shown in FIG. 9, the thickness T of the laminated sheet is 0.4 mm, the height h of the convex portion is 0.4 mm, and the embossed uneven portion 15 protruding 0.4 mm from the back surface 10 b of the laminated sheet 10 is formed. It had been.
In Example 1, a silicon roll was used as the receiving roll 31, and the embossed spin embedding amount could be increased by the above pressing force (25 kg / cm ² ), and the embossed uneven portion was formed by deep drawing embossing.
The embossed concavo-convex part was a sheet integrated with the three layers of the overlap sheet 13 being mechanically fitted, with no melt adhesion joining at the bottom of the concave part being confirmed.
In the air permeability test of this laminated sheet using a Frazier type air permeability tester, the value of air permeability was 4.3, and the air permeability was good.

<Comparative Example 1>
A laminated sheet of Comparative Example 1 was produced under the following conditions.
A laminated sheet was produced in the same manner as in Example 1 except that the material of the receiving roll 31 was nylon resin (hardness 100 °).
A laminated sheet manufactured under these conditions is shown in FIG.
FIG. 10 is an enlarged view of the embossed uneven portion of the laminated sheet according to Comparative Example 1, which is strongly pressed, (a) is a cut sectional view, and (b) is a plan view.
From FIG. 10, the thickness T of the laminated sheet was 0.4 mm, and the height h of the convex portion was 0 mm.
In the laminated sheet of Comparative Example 1, the formation of an embossed concavo-convex portion that was deep-drawn from the back surface 10b was not recognized, and a sticky flat laminated sheet having no concavo-convex feeling was produced.
Since the nylon roll harder than the silicon roll was used as the receiving roll 31, it was considered that embossed spins were not buried and the embossed concavo-convex portion subjected to deep drawing was not formed.
Therefore, in FIG.10 (b), the bottom part (center round shape) pressed with the embossing roll 21 appears discolored black.
As shown in FIG. 10A, the bottom portion (thickness 0.1 mm) observed in black was in a state where the three-layer sheets were in close contact with each other.
When the evaluation of air permeability was tested, it was found that the air permeability was 3.5 and the air permeability of the laminated sheet as a whole was poor.

<Example 2>
The laminated sheet of Example 2 was manufactured under the following conditions.
(1) Manufacturing conditions Pin diameter of the embossing roll 21: 9 mm
The embossed pins were arranged so that the ratio of the embossed irregularities per unit area was 23% (in plan view).
Other conditions were the same as in Example 1.
(2) The manufactured laminated sheet has a thickness T of 0.4 mm, the height h of the convex portion is 0.4 mm, and an embossed concavo-convex portion 15 protruding 0.4 mm from the back surface 10b of the laminated sheet is formed. It was.
Using a silicon roll as the receiving roll 31, the embossed spin embedding amount can be increased by the above pressing force (25 kg / cm ² ), and the embossed uneven portion was formed by deep drawing embossing.
The embossed concavo-convex portion was a sheet integrated with the three layers of the overlapped sheet 13 mechanically fitted, without being confirmed by melt adhesion at the bottom of the concave portion.
In the air permeability test of this laminated sheet using a Frazier type air permeability tester, the value of air permeability was 5.0, and the air permeability was good.

<Comparative example 2>
A laminated sheet was produced in the same manner as in Example 2 except that the material of the receiving roll 31 was nylon resin (hardness 100 °).
Since the nylon roll harder than the silicon roll was used for the receiving roll 31, embossed spin was not embedded and the embossed uneven part was not formed.
Therefore, in FIG.10 (b), the bottom part (round shape of the center) pressed with the embossing roll 21 appeared discolored black.
When the evaluation of air permeability was tested, it was found that the air permeability was 3.6 and the air permeability of the laminated sheet as a whole was poor.

Table 1 summarizes the air permeability test results of Examples 1 and 2 and Comparative Examples 1 and 2.

Since the laminated sheet of the present invention is excellent in air permeability, it can be suitably used particularly as an industrial air filter or liquid filter.

10 Laminated sheet 10a Laminated sheet surface 10b Laminated sheet back surface 11 Adhesive sheet (for example, melt blown nonwoven fabric)
12, 12 Non-woven fabric located on the front and back (for example, spunbond nonwoven fabric)
13 Overlapping sheet 15 Embossed uneven portion 15a Convex portion 15b Recessed portion 15c formed on the surface of the laminated sheet Bottom surface 15d of embossed uneven portion Side wall 15e of recessed portion Strongly crimped portion 15f strongly pressed in a ring shape Embossed uneven portion mouth portion 21 Embossed Roll 21a Base surface 22 Embossed spin 22a Embossed spin tip 22e Surface with roughened surface (jagged state)
22d Embossed spin inclined part 22f Ring-shaped strong pressing part 22g Protruding part 31 Receiving roll C Gap h Convex height S Concave depth T Laminated sheet thickness

Claims (8)

An adhesive sheet located in the middle;
A non-woven fabric located on the front and back is laminated and integrated, and is a laminated sheet of at least three layers,
The laminated sheet has embossed irregularities;
The overlapping sheets are fitted and joined only at the embossed irregularities ,
The height of the convex part of the said embossing uneven | corrugated | grooved part protrudes rather than the back surface of a laminated sheet, The laminated sheet characterized by the above-mentioned. The depth of the recessed part of the said embossing uneven | corrugated | grooved part is larger than the thickness of a lamination sheet, The lamination sheet of Claim 1 characterized by the above-mentioned. The laminated sheet according to claim 1 or 2 , wherein the outer peripheral edge of the bottom surface of the concave portion of the embossed concave-convex portion has a strong pressure-bonding portion that is strongly pressure-bonded in a ring shape. Between the embossing roll and its receiving roll,
An adhesive sheet located in the middle;
By passing the overlapping sheet with the nonwoven fabric positioned on the front and back,
Press the embossed pin formed to stand from the base surface of the embossing roll against the surface of the overlapping sheet,
A method for producing a laminated sheet for forming an embossed uneven portion on a laminated sheet,
When the laminated sheet passes between the embossing roll and its receiving roll,
The embossing pin tip of the embossing roll is brought into contact with the overlapping sheet and embedded in the receiving roll,
Deep drawing embossing to form embossed irregularities,
The manufacturing method of the lamination sheet | seat characterized by making the said adhesive sheet and the said nonwoven fabric fit in the embossing uneven | corrugated | grooved part. On the outer peripheral edge of the tip of the embossed pin, a ring-shaped strong pressing part is provided,
Strongly pressure-bond the bottom surface of the concave portion of the embossed uneven portion with the strong pressing portion,
The method for producing a laminated sheet according to claim 4 , wherein a ring-shaped strong pressure bonding portion is formed on the outer peripheral edge of the bottom surface of the concave portion. A ring-shaped strong pressing portion provided at the outer peripheral edge of the tip portion of the embossed pin,
It has a protruding portion extending in the height direction of the embossed spin,
The bottom surface of the concave portion of the embossed concave and convex portion is strongly pressure-bonded with the protruding portion,
The method for producing a laminated sheet according to claim 5 , wherein a ring-shaped strong pressure bonding portion is formed on the outer peripheral edge of the bottom surface of the concave portion. When the laminated sheet passes between the embossing roll and the receiving roll,
The base surface of the embossing roll is
It has a clearance gap so that it may not contact with the opposing nonwoven fabric, The manufacturing method of the laminated sheet of any one of Claims 4-6 characterized by the above-mentioned. Irradiate light from one side of the laminated sheet laminated with the embossing roll and its receiving roll,
The method for producing a laminated sheet according to any one of claims 4 to 7 , wherein an embossed uneven portion formed on the laminated sheet is monitored from the other side.