CN115515782B - Method for manufacturing laminated sheet, method for manufacturing sanitary mask, and laminated sheet - Google Patents

Abstract

The present invention provides a translucent laminate suitable for a sanitary mask which is excellent in visibility of expression of a wearer and ventilation and has trapping property effective for preventing spreading of spray. The laminated sheet (S) is provided with: a sheet-like laminate (4) in which at least a first base layer (1) formed of a plurality of thermoplastic fibers and a second base layer (2) formed of a plurality of thermoplastic fibers finer than the fibers of the first base layer (1) are superimposed; and a plurality of melt-curing units (5) from the front surface to the back surface of the sheet-like laminate (4), wherein the plurality of melt-curing units (5) are formed on the sheet-like laminate (4) by adjusting the area ratio of the sum of the occupied areas to the area of the sheet-like laminate (4) to obtain desired air permeability and transparency.

Description

Method for manufacturing laminated sheet, method for manufacturing sanitary mask, and laminated sheet

Technical Field

The present invention relates to a translucent laminate sheet having air permeability and trapping properties of pollen, saliva, sputum, etc. in the air, a sanitary mask using the laminate sheet, and a method for producing the laminate sheet.

Background

Conventionally, there are sanitary masks for wearing on the face to cover the nostrils and mouth to prevent infection such as cold, and there are cloth masks and masks in which a nonwoven fabric having a high stretchability and an antibacterial agent is bonded to a polyurethane spunbond nonwoven fabric as disclosed in patent document 1. Further, there is a sanitary mask including a plurality of nonwoven fabric filters as disclosed in patent document 2. Patent document 3 discloses a mask in which a transparent soft sheet material that can be transmitted from the outside to observe the face of a wearer is formed into a mask body that covers the mouth and nose of the wearer.

Prior art literature

Patent literature

Patent document 1: japanese laid-open patent publication No. 62-149353

Patent document 2: japanese patent application registration No. 3220086

Patent document 3: japanese patent application registration No. 3185729

Disclosure of Invention

Problems to be solved by the utility model

However, conventional sanitary masks made of cloth and conventional sanitary masks in which nonwoven fabrics having high stretchability are bonded to nonwoven fabrics having an antibacterial agent attached thereto are insufficient in terms of mesh size to prevent spreading of droplets such as saliva and sputum.

In addition, although the conventional sanitary mask including a plurality of nonwoven fabric filters is effective in preventing the spread of the spray, the mouth and nose are shielded when the sanitary mask is worn, like the conventional sanitary mask made of cloth or nonwoven fabric, and therefore the expression of the wearer cannot be distinguished, and the sanitary mask cannot be said to be sufficient from the viewpoints of good communication with the wearer of the mask, prevention of crimes, and the like.

Further, although a sanitary mask in which the whole mask body is formed of a transparent flexible sheet is effective in terms of communication in a good sense and prevention of crimes, a transparent resin film is used as the flexible sheet, and in order to ensure proper ventilation, it is necessary to form a plurality of minute ventilation holes capable of preventing diffusion of droplets such as saliva and sputum, and it is very difficult to form the plurality of minute ventilation holes in the resin film, and it is actually difficult to obtain a mask which is effective for prevention of infectious diseases and has good ventilation, and development of a high-level processing technique for forming minute ventilation holes, expensive processing equipment, and the like are required.

In particular, after the expansion of the infection with the novel coronavirus, the demand for the function of the sanitary mask expands to the function of eliminating the inconvenience of communication and the dyspnea when the sanitary mask is worn, in addition to the function of preventing the infection, due to the change of the life style of the sanitary mask which is normalized when the sanitary mask is worn.

The present invention has been made in view of such circumstances. The main object of the present invention is to provide a translucent laminate suitable for a sanitary mask which is excellent in visibility and ventilation of the expression of the wearer and has trapping properties effective for preventing spreading of droplets such as saliva and sputum.

Another object of the present invention is to provide a relatively inexpensive sanitary mask which is excellent in visibility of expression and ventilation of a wearer and has trapping properties effective for preventing spreading of droplets such as saliva and sputum.

The technical scheme and the invention for solving the problems

According to the laminate sheet according to the first aspect of the present invention, the laminate sheet may be configured to include: a sheet-like laminate having at least a first base material layer formed of a plurality of thermoplastic fibers and a second base material layer formed of a plurality of thermoplastic fibers finer than the fibers of the first base material layer; and a plurality of melt-curing units formed on the sheet-like laminate from the front surface to the back surface thereof, wherein the plurality of melt-curing units adjust the area ratio of the sum of the occupied areas to the area of the sheet-like laminate to obtain desired air permeability and transparency.

According to the above configuration, a translucent laminate sheet suitable for a sanitary mask having excellent visibility and ventilation of the expression of the wearer and having trapping property effective for preventing spreading of droplets such as saliva and expectoration can be mass-produced at relatively low cost.

According to the laminate sheet of the second aspect of the present invention, the plurality of melt-solidified portions may have a desired occupied area and may be dispersed in the sheet-like laminate body.

According to the laminate sheet of the third aspect of the present invention, the plurality of melt-solidified portions may each be elongated in a groove shape in a certain direction and have a desired width, and may be arranged on the sheet-like laminate body at desired intervals.

According to the laminate sheet of the fourth aspect of the present invention, the sheet-like laminate may have a third base layer formed of a plurality of thermoplastic fibers on the side of the second base layer opposite to the first base layer.

According to the laminate sheet according to the fifth aspect of the present invention, the area ratio may be in a range of 10% to 80%. According to the above configuration, desired air permeability and transparency can be obtained.

According to the laminate sheet of the sixth aspect of the present invention, the plurality of melt-solidified portions may be distributed to each of the plurality of virtual boundary frames having the same shape and size and being in contact with each other without gaps, which are set on the surface of the sheet-like laminate body, and may be surrounded by the virtual boundary frames, and may be uniformly distributed on the surface of the sheet-like laminate body so that the occupied area of the melt-solidified portions of each virtual boundary frame is the same.

According to the above configuration, by calculating the ratio of the occupied area of the melt-solidified portion to the area of the virtual boundary frame with respect to one virtual boundary frame, the area ratio of the sum of the occupied areas of the melt-solidified portions to the area of the whole of the distribution area of the melt-solidified portion of the sheet-like laminate can be calculated with respect to the whole of the distribution area of the melt-solidified portion of the sheet-like laminate, and therefore, an appropriate shape, size, arrangement interval, and the like of the melt-solidified portion can be obtained effectively.

According to the laminated sheet of the seventh aspect of the present invention, the total light transmittance of the laminated sheet may be 70% or more, the pressure loss in the filter performance test in which the supply amount of air is set so that the wind speed of air passing through the laminated sheet is 20 cm per second may be 300 pascals or less, the number of particles of 0.3 to 0.5 μm contained in the air on the upstream side and the downstream side may be measured by a particle counter in the filter performance test, and the collection efficiency of the laminated sheet may be 60% or more when the ratio of the difference between the measured number of particles on the upstream side and the number of particles on the downstream side to the number of particles on the upstream side is set to the collection efficiency, and the area of the non-molten portion in the frame may be 400 square millimeters or less when the portion other than the molten solidified portion in the virtual boundary frame is the non-molten portion in the frame.

According to the sanitary mask according to the eighth aspect of the present invention, any one of the laminated sheets according to the first to seventh aspects of the present invention may be used for the mask body.

According to the method for manufacturing a laminated sheet according to the ninth aspect of the present invention, the method may include: a step of forming a sheet-like laminate by superposing at least a first base material layer formed of a plurality of thermoplastic fibers and a second base material layer formed of a plurality of thermoplastic fibers formed of fibers finer than the fibers of the first base material layer; and forming a plurality of melt-cured portions from the front surface to the back surface of the sheet-like laminate to the sheet-like laminate so as to adjust the respective occupied areas and the area ratio of the sum of the respective occupied areas to the area of the sheet-like laminate and to obtain desired air permeability and transparency.

Drawings

Fig. 1 is a plan view schematically showing an enlarged part of a laminated sheet according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view schematically showing A-A in fig. 1 in a cross-section.

Fig. 3 is an illustration of one apparatus used in the manufacture of the laminate.

Fig. 4 is an explanatory view of another apparatus used in manufacturing the laminated sheet.

Fig. 5 is a plan view schematically showing another example of the shape of the melt-solidified portion.

Fig. 6 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Fig. 7 is a front view of a sanitary mask according to a first embodiment of the present invention.

Fig. 8 is a perspective view showing a state of wearing the sanitary mask.

Fig. 9 is a plan view schematically showing an enlarged portion of a laminate sheet according to a second embodiment of the present invention.

Fig. 10 is a cross-sectional view schematically showing a cross-section B-B in fig. 9.

Fig. 11 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Fig. 12 is a photograph used for examining the visibility of the laminate sheet of example 1.

Fig. 13 is a photograph used for examining the visibility of the laminate sheet of example 2.

Fig. 14 is a photograph used for examining the visibility of the laminate sheet of example 3.

Fig. 15 is a photograph used for examining the visibility of the laminate sheet of example 4.

Fig. 16 is a photograph used for examining the visibility of the laminate sheet of comparative example 1.

Fig. 17 is a photograph used for examining the visibility of the laminate sheet of comparative example 2.

Fig. 18 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Fig. 19 is a photograph used for examining the visibility of the laminate sheet of example 5.

Fig. 20 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Fig. 21 is a photograph used for examining the visibility of the laminate sheet of example 6.

Fig. 22 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Fig. 23 is a photograph used for examining the visibility of the laminate sheet of example 7.

Fig. 24 is a front view of a sanitary mask according to a third embodiment of the present invention.

Fig. 25 is a plan view schematically showing still another example of the shape of the melt-solidified portion.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are examples of laminates and sanitary masks for embodying the technical ideas of the present invention and a method for producing the laminates, and the present invention is not limited to the following. In addition, the present specification does not specify the components shown in the claimed scope as components of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent parts described in the embodiments are not intended to limit the scope of the present invention to these examples unless specifically described otherwise. The sizes, positional relationships, and the like of the components shown in the drawings may be exaggerated for clarity of description. In the following description, the same or equivalent members are denoted by the same names and reference numerals, and detailed description thereof is appropriately omitted. The elements constituting the present invention may be constituted by a plurality of elements formed by the same member and a single member may also be used as a plurality of elements, or the functions of a single member may be shared by a plurality of members.

(first embodiment)

As shown in fig. 1 and 2, the laminated sheet S includes: a sheet-like laminate 4 having a first base layer 1 formed of a plurality of thermoplastic fibers, a second base layer 2 formed of a plurality of thermoplastic fibers finer than the fibers of the first base layer 1, and a third base layer 3 disposed on the opposite side of the second base layer 2 from the first base layer 1; and a plurality of melt-solidified portions 5 formed in the sheet-like layered body 4.

The first substrate layer 1 is formed of a nonwoven fabric having a fiber diameter of 5 μm or more, and the second substrate layer 2 is formed of a nonwoven fabric containing nanofiber fibers of less than 1000 nm. The third base material layer 3 is also formed of a nonwoven fabric having a fiber diameter of 5 μm or more.

The plurality of melt-solidified portions 5 are dispersed on the sheet-like laminated body 4, and the sheet-like laminated body 4 is heated by being partially sandwiched from both front and back sides, whereby the first base material layer 1, the second base material layer 2, and the third base material layer 3 are brought into a molten state in the heated portions, and thereafter the molten portions are cooled and solidified, thereby forming the sheet-like laminated body 4 from the front surface to the back surface.

The melt-solidified section 5 is formed by welding the first base material layer 1 and the second base material layer 2, and the second base material layer 2 and the third base material layer 3, and is formed by cooling and solidifying the plurality of fibers after the fibers are in a molten state, that is, a state in which the fibers are completely melted up to the center of each fiber or a state in which a part of each fiber is melted. Therefore, the melt-solidified portion 5 does not reflect and scatter light as in the case of a melt-solidified portion made of a plurality of fibers, and therefore becomes a melt-solidified portion having high transparency and no or very low air permeability.

In contrast, the first base material layer 1, the second base material layer 2, and the third base material layer 3 are not melted like the melt-solidified portion 5 but are simply overlapped with the non-melted portion 6, which is a portion other than the melt-solidified portion 5 of the sheet-like laminate 4, and therefore, the sheet-like laminate has air permeability, but light is reflected and scattered by a plurality of fibers, and therefore, the sheet-like laminate is opaque.

Therefore, the sheet-like laminate 4 includes the transparent melt-solidified portion 5 and the opaque and breathable non-melt portion 6, and is a net with the non-melt portion 6 as a thread and the melt-solidified portion 5 as a mesh, for example, in light, so that the laminate sheet S is translucent as a whole.

Here, when the sheet laminate 4 includes a plurality of melt-solidified portions 5, the size of the sheet laminate 4 in the plan view in the set measurement region is defined as the area of the sheet laminate 4, the size of the melt-solidified portions 5 in the plan view is defined as the occupied area of the melt-solidified portions 5, and the size of the non-melted portions 6 in the plan view is defined as the area of the non-melted portions. The sum of the occupied areas of all the melt-solidified portions 5 located in the set measurement region is defined as the sum of the occupied areas of the melt-solidified portions 5, and the ratio of the sum of the occupied areas of the melt-solidified portions 5 to the area of the sheet-like laminate 4 is defined as the area ratio.

In the laminated sheet S, if the area ratio is reduced, the air permeability is improved, but the amount of transmitted light is reduced, so that the transparency of the laminated sheet S is reduced, whereas if the area ratio is increased, the transparency is improved, but the air permeability tends to be reduced. When the transparency of the laminate sheet S is improved, visibility through an object on the back side of the laminate sheet S is improved. When the area ratio is the same, if the occupied area of each of the melt-solidified portions 5 is increased, the resolution of the laminate sheet S with respect to the object tends to be lowered and the visibility tends to be lowered when the object disposed behind the laminate sheet S is visually recognized through the laminate sheet S. Accordingly, the plurality of melt-solidified portions 5 are formed by adjusting the occupied area and the area ratio thereof, so as to obtain desired air permeability and transparency. The required occupied area and the required area ratio of the melt-solidified section 5 for obtaining the required air permeability and transparency can be obtained by, for example, trial and error. As a result, it is preferable that the area ratio is 10% or more and 80% or less in order to provide practical properties of air permeability and transparency.

(laminate manufacturing method)

Next, a method for manufacturing the laminated sheet S will be described.

To manufacture the laminated sheet S, first, a sheet-like laminate 4 is formed, the sheet-like laminate 4 having a first base layer 1 formed of a plurality of thermoplastic fibers, a second base layer 2 formed of a plurality of thermoplastic fibers finer than the fibers of the first base layer 1, and a third base layer 3 formed of a plurality of thermoplastic fibers on the opposite side of the second base layer 2 from the first base layer 1. The second base material layer 2 mainly serves as a filter for preventing the spread of droplets.

Next, the plurality of melt-solidified portions 5 from the front surface to the back surface of the sheet-like laminate 4 are formed in the laminate sheet S so as to adjust the respective occupied areas and the area ratio of the sum of the respective occupied areas to the area of the sheet-like laminate to obtain desired air permeability and transparency.

In the present embodiment, for example, the apparatus shown in fig. 3 and the apparatus shown in fig. 4 are used to form the sheet-like laminated body 4. The nonwoven fabric to be used as the first base material layer 1 and the third base material layer 3 is a nonwoven fabric formed into a tape shape and wound into a roll shape. As shown in fig. 3, the nonwoven fabric 1a serving as the first base material layer 1 is unwound from the raw material roll R1 and fed to a known nanofiber spinning apparatus M1, and nanofibers are spun on the lower surface of the first base material layer 1 by an electrospinning method (japanese) to form a primary laminate 7 in which the nonwoven fabric 2a serving as the second base material layer 2 is stacked on the first base material layer 1, and the primary laminate 7 is wound up to form the raw material roll R7.

Next, as shown in fig. 4, the primary laminate 7 is unwound from the raw material roll R7, and the nonwoven fabric 3a serving as the third base material layer is unwound from the raw material roll R3, and fed to the pair of guide rollers 21 and 22, so that the nonwoven fabric 3a serving as the third base material layer 3 is overlapped on the upper surface of the second base material layer 2 of the primary laminate 7 to form the sheet-like laminate 4.

By forming the sheet-like laminate 4 in this manner, even if the nonwoven fabric 2a serving as the second base material layer 2 is complicated to handle alone, it is possible to handle the nonwoven fabric 2a serving as the second base material layer 2 by integrating it with the first base material layer 1 when it is overlapped with the nonwoven fabric 3a serving as the third base material layer 3 or the like.

In fig. 4, the sheet-like laminated body 4 having passed the guide rollers 21, 22 (there are cases where the guide rollers 21, 22 are not required) further advances to the embossing device M2. The embossing device M2 includes: the embossing roller 23 has a plurality of convex portions 23a regularly arranged on the outer periphery; and a support roller 24.

The plurality of protruding portions 23a are regularly arranged on the outer peripheral surface of the embossing roller 23 at predetermined mutual intervals in the width direction and the circumferential direction, respectively. The tip end surface of each convex portion 23a is formed in the same shape as the melt-solidified portion 5, and is heated by induction heating or direct heating during rotation. The outer peripheral surface of the support roller 24 is flat and is heated by induction heating or direct heating during rotation. The sheet-like laminated body 4 is pressed and heated by sandwiching the outer peripheral surfaces of the convex portions 23a of the embossing roller 23 and the support roller 24 from both front and back sides when passing through the rotary embossing device M2, and a plurality of melt-solidified portions 5 are regularly and repeatedly formed on both front and back sides of the sheet-like laminated body 4. The sheet-like laminated body 4 is formed with a plurality of melt-solidified portions 5 thereon to form a laminated sheet S, and the laminated sheet S is wound to form a winding roll R. The embossing of the sheet-like laminate 4 is also useful in that transparency can be imparted to the laminate sheet S, for example, in that deflection of the nano-filter layer can be reduced to improve durability, in that filter performance (virus trapping performance) can be maintained, and in that the touch of the substrate can be adjusted.

In the case where the first and third base material layers 1 and 3 are subjected to hydrophilic treatment, the nonwoven fabric 1a or the nonwoven fabrics 1a and 3a are subjected to hydrophilic treatment before the nonwoven fabric 2a is superimposed on the nonwoven fabric 1 a. The hydrophilic treatment is performed, for example, by adding a known hydrophilic agent to the nonwoven fabric 1a or the nonwoven fabric 3a in the production process of the nonwoven fabric, or by adding a known hydrophilic agent to the fibers at the time of producing the fibers and then producing the nonwoven fabric from the fibers. Alternatively, the apparatus shown in fig. 4 may be replaced with an apparatus provided with a winding apparatus for winding the sheet-like laminate 4 instead of the embossing apparatus M2, and a winding apparatus provided with the embossing apparatus M2 may be provided, and the melt-solidified portion 5 may be formed in the winding apparatus. In order to form the melt-solidified portion 5, other heating devices such as an ultrasonic bonding device that sandwiches the sheet-like laminated body 4 with an embossing roller and an ultrasonic horn and ultrasonically vibrates the ultrasonic horn to melt and bond the sheet-like laminated body 4 may be used instead of the embossing device M2. The shape of the melt-solidified portion 5 is not limited to the shape shown in fig. 1, and may be, for example, the shape shown in fig. 5 and 6.

The sanitary mask 10 shown in fig. 7 includes a mask body 11 and ear hanging parts 12 provided on both left and right sides of the mask body 11, and when the sanitary mask is worn on the face, the mask body 11 covers the mouth 13 and the nose 14 as shown in fig. 8. The sanitary mask 10 uses the laminate sheet S shown in fig. 1 and 2 as the mask body 11, and the first base material layer 1 shown in fig. 2 is disposed on the side contacting the face to form the inner layer of the mask body 11, and is subjected to hydrophilic treatment. The third base material layer 3 is disposed on the side not contacting the face and serves as the outer layer of the mask body 11. The second base layer 2 is a middle layer of the mask body 11 for preventing spreading of droplets such as saliva and sputum. The sanitary mask 10 is not limited to the type having the ear-hanging portion 12 made of, for example, rubber or nonwoven fabric, but includes, for example, a type having nonwoven fabric in which the ear-hanging portion 12 is integrally formed or press-formed with the mask body 11, and an adhesive type having no ear-hanging portion 12 in which an adhesive portion is provided in the mask itself. The shape of the mask body 11 is not particularly limited, and may be, for example, a three-dimensional shape in which a lancet shape is formed.

If the first base material layer 1 or the third base material layer 3 is subjected to the hydrophilic treatment in advance, and the first base material layer 1 or the third base material layer 3 subjected to the hydrophilic treatment is disposed on the side contacting the face in the sanitary mask 10, even if the water vapor in the breathing of the wearer of the sanitary mask 10 is condensed, the first base material layer 1 or the third base material layer 3 plays a role of helping the diffusion of the condensed water droplets to evaporate, so that the inner layer contacting the face can be prevented from being wetted by the condensed water to cause a sense of discomfort.

(second embodiment)

Fig. 9 and 10 show a second embodiment of the present invention, which differs from the laminate sheet S of the first embodiment in that a plurality of melt-solidified sections 5 each extend in a groove shape in a certain direction and have a desired width to obtain a desired air permeability and transparency, and are arranged on a sheet-like laminate 4 at a desired mutual interval.

The plurality of groove-shaped melt-solidified portions 5 shown in fig. 9 are constituted by melt-solidified portions extending in the longitudinal direction and melt-solidified portions extending in the lateral direction that intersect each other, but may be melt-solidified portions extending only in one direction so as not to intersect each other. The required width of each groove-shaped melt-solidified portion 5 and the required interval between the groove-shaped melt-solidified portions 5 can be obtained by trial and error. The shape of the melt-solidified portion 5 and the non-melt portion 6 is not limited to the shape shown in fig. 9, and may be, for example, the shape shown in fig. 11.

The plurality of melt-solidified portions 5 also have an effect of narrowing the flow path of air to improve the trapping property of particles by the laminate sheet S, and the shape and arrangement of each melt-solidified portion 5 are determined in consideration of air permeability and transparency. Preferably, the final sensory evaluation is performed, and the judgment is performed comprehensively.

(imaginary bounding Box)

In order to grasp the area ratio of the plurality of melt-solidified portions 5 to the entire area of the laminate sheet S, the sum of the occupied areas of the respective melt-solidified portions 5 is required. The mask body 11 shown in fig. 7 is formed of a rectangular laminated sheet S having a longitudinal length of 13 cm and a transverse length of 16 cm. In the laminate sheet S having such a large area, it is troublesome to find the areas of the plurality of melt-solidified portions 5 one by one and to aggregate them. In order to avoid this trouble and to make the performance of the laminated sheet S as uniform as possible over the entire surface area thereof, for example, as shown in fig. 1, a plurality of virtual bounding boxes P having the same shape and size as each other and being in contact with each other without gaps are set on the surface of the sheet-like laminated body 4. In fig. 1, a quadrangle surrounded by a point a, b, c, d is an imaginary bounding box P. The plurality of melt-solidified portions 5 are distributed to each virtual boundary frame P, and are uniformly distributed on the surface of the sheet-like layered body 4 so that the occupied area of the melt-solidified portion 5 of each virtual boundary frame P is the same. Therefore, the area ratio of the entire area of the distribution region of the melt-solidified portions 5 in the laminate sheet S is equal to the ratio of the occupied area of one melt-solidified portion 5 to the area of one virtual boundary box P. If the ratio is defined as the in-frame area ratio and the portion other than the melt-solidified portion 5 in one virtual boundary frame P is defined as the in-frame non-melted portion 6a, the area of one virtual boundary frame P and the area of the in-frame non-melted portion 6a can be calculated based on the area of the melt-solidified portion 5 in the virtual boundary frame P and the in-frame area ratio, respectively.

The periphery of each of the plurality of melt-solidified portions 5 shown in fig. 1 is surrounded by an in-frame non-melt portion 6 a. The virtual boundary box P surrounds one melt-solidified portion 5 and an in-box non-melted portion 6a around the melt-solidified portion 5. In fig. 5, 6, 9, 11, 18, 20, and 22, quadrangles shown by two-dot chain lines are virtual bounding boxes P. The virtual boundary box P shown in fig. 9 and 11 encloses a part 5a of one melt-solidified portion 5 and each part 6a of four non-melt portions 6, and in this case, the in-frame non-melt portions 6a are composed of four parts 6 a.

The shape and number of the melt-solidified portions 5 in each virtual boundary box P are not limited to the same shape and number. It is also possible to have different shapes of the melt-solidified portions 5 or a plurality of the melt-solidified portions 5 in one virtual boundary frame P, or to have different shapes and sizes of the plurality of the melt-solidified portions 5 in one virtual boundary frame P, or to have different numbers of the melt-solidified portions 5 between the virtual boundary frames P. Even in this case, as long as the sum of the occupied areas of one or more melt-solidified portions 5 surrounded by one virtual boundary frame P is the same in each virtual boundary frame P, it can be considered that the melt-solidified portions 5 are uniformly distributed on the surface of the sheet-like laminated body 4.

When the area of the virtual boundary box P becomes large, the resolution of the laminate sheet S with respect to the object to be visually recognized is lowered when the laminate sheet S is visually recognized. The resolution here means the size of one virtual boundary frame P, and when the resolution is changed with the above-described frame inner area ratio being constant, the area of the virtual boundary frame P increases, and when the resolution decreases, the area of the melt-solidified portion 5 in the virtual boundary frame P and the area of the non-melt portion 6a in the frame increase, and the area of the portion of the face of the wearer of the sanitary mask covered by the non-melt portion 6a in one frame increases, making it difficult to capture the expression of the wearer of the sanitary mask 10. Therefore, when the resolution of the laminated sheet S is too small, the area of the virtual boundary box P needs to be reduced so that the area of the in-box non-melted portion 6a is within an appropriate range. Since the influence of the resolution on the ventilation is smaller than the frame inner area ratio, the appropriate range of the resolution can be grasped, for example, by making a plurality of laminates S having the same frame inner area ratio and different areas of the non-melted portions 6a in the frame by a computer, combining the laminates S and face photographs taken at the corners of the mouth and the nose for each laminate S, displaying the resultant laminate on a display screen, and judging whether the resolution is good or not based on the condition of the face photographs viewed through the laminates S.

Example 1

Next, an embodiment of the laminated sheet S of the present invention will be described.

Example 1

As the first base material layer 1, a spun-bonded nonwoven fabric having a weight per unit area of 15 g and using polypropylene (PP) as a raw material was used, as the second base material layer 2, a nonwoven fabric having a weight per unit area of 0.2 g and using polyvinylidene fluoride (PVDF) as a raw material was spun by an electrospinning method was used, as the third base material layer 3, a spun-bonded nonwoven fabric having a weight per unit area of 15 g and using polypropylene (PP) as a raw material was used, and the first base material layer 1, the second base material layer 2, and the third base material layer 3 were stacked so that the second base material layer 2 was arranged between the first base material layer 1 and the third base material layer 3, and a plurality of melt-cured portions 5 having a shape as shown in fig. 1 were formed on the sheet-like stacked body 4 by an embossing device M2, thereby producing a laminated sheet-like sheet S1.

The tip end surface of the convex portion 23a of the embossing roller 23 of the embossing device M2 used in forming the plurality of melt-solidified portions 5 has the same shape as the shape of the melt-solidified portions 5 shown in fig. 1. The area ratio was 21%. When this area ratio is obtained, the area of the distal end surface of the convex portion 23a of the embossing roller 23 is substantially the same as the area of the melt-solidified portion 5, and therefore the area of the distal end surface of the convex portion 23a is used as the area of the melt-solidified portion 5.

In addition, strictly speaking, the shape of the plurality of melt-solidified portions 5 is deformed or contracted by melt solidification, and therefore, is slightly different from the shape of the tip end surfaces of the convex portions 23a of the embossing roller 23, respectively. Therefore, in examples 1 to 4, the occupied area and the area ratio of the melt-solidified portion 5 were calculated from the shape and arrangement of the convex portions 23a of the embossing roller 23 used in the processing.

The surface temperature of the convex portion 23a of the embossing roller 23 at the time of forming the melt-solidified portion 5 was 148 degrees celsius, the surface temperature of the backup roller was 148 degrees celsius, and a pressing force of 60 kg per 1 cm width of the sheet-like laminate 4 was applied to the sheet-like laminate 4 by the embossing roller 23 and the backup roller 24 while the sheet-like laminate 4 was traveling at a speed of 3 meters per minute.

In order to evaluate the air permeability and particle trapping property of the laminate sheet S1, a performance test of the mask filter (hereinafter referred to as a filter performance test) was performed on the laminate sheet S1. At this time, in the test apparatus, the air supply amount was set so that the air velocity of the air passing through the laminate sheet S1 was 20 cm per second, the pressure loss when the air passed through the laminate sheet S1 was measured, the number of particles of 0.3 to 0.5 μm contained in the air on the upstream side and the downstream side of the laminate sheet S1 was measured by a particle counter, and the collection efficiency was obtained by the following formula (formula 1).

(mathematics 1)

Trapping efficiency= (number of particles on upstream side-number of particles on downstream side)/(number of particles on upstream side)

As a result of the above-described filter performance test, the pressure loss was 123.1 Pa, and the trapping efficiency was 80.0%.

To evaluate the visibility of the laminate sheet S1, the total light transmittance of the laminate sheet S1 was measured using a spectrophotometer (V-570) manufactured by japan spectroscopy corporation for a rectangular portion having one side of 6.7mm×9.8mm as a part of the laminate sheet S1. As a result, the total light transmittance was 72.9%. Further, a face photograph of a mouth angle and a nose of a substantially real size is placed behind the laminate sheet S1, and the mouth angle and the nose of the photograph are observed through the laminate sheet S1, whereby the visibility of the laminate sheet S1 is examined visually. As a result, the mouth and nose are clearly visible, although not to the extent that they are observed through the mask of the transparent film. Fig. 12 is a photograph taken at this time.

Example 2

Using the sheet-like laminated body 4 formed in the same manner as in example 1, a plurality of melt-solidified portions 5 having a shape similar to that shown in fig. 5 were formed on the sheet-like laminated body 4 by an embossing apparatus M2, and a laminated sheet S2 was produced.

The shape of the distal end surface of the convex portion 23a of the embossing roller 23 of the embossing device M2 used in forming the plurality of melt-solidified portions 5 is the same as the shape of the melt-solidified portions 5 shown in fig. 5, and the area ratio is 25%. The surface temperature of the convex portion 23a of the embossing roller 23 at the time of forming the melt-solidified portion 5 was 145 degrees celsius, the surface temperature of the backup roller was 145 degrees celsius, and other processing conditions were the same as in example 1.

In order to evaluate the air permeability and the particle trapping property of the laminated sheet S2, a filter performance test was performed in the same manner as in example 1.

As a result of the filter performance test, the pressure loss was 120.8 Pa, and the trapping efficiency was 73.6%.

In addition, in order to evaluate the visibility of the produced laminated sheet S2, the total light transmittance was obtained in the same manner as in example 1, and the visibility was examined visually. As a result, the total light transmittance was 75.1%, and the mouth and nose were clearly seen by visual observation although the degree of observation was not achieved by the mask of the transparent film. Fig. 13 is a photograph taken at this time.

Example 3

Using the sheet-like laminated body 4 formed in the same manner as in example 1, a plurality of melt-solidified portions 5 having a shape similar to that shown in fig. 6 were formed on the sheet-like laminated body 4 by the embossing device M2, and a laminated sheet S3 was produced.

The shape of the distal end surface of the convex portion 23a of the embossing roller 23 of the embossing device M2 used in forming the plurality of melt-solidified portions 5 was the same as the shape of the melt-solidified portion 5 shown in fig. 6, and the area ratio was 52%. The surface temperature of the convex portion 23a of the embossing roller 23 at the time of forming the melt-solidified portion 5 was 145 degrees celsius, the surface temperature of the backup roller 24 was 145 degrees celsius, and other processing conditions were the same as in example 1.

In order to evaluate the air permeability and the particle trapping property of the laminated sheet S3, a filter performance test was performed in the same manner as in example 1.

As a result of the filter performance test, the pressure loss was 133.8 Pa, and the trapping efficiency was 75.7%.

In addition, in order to evaluate the visibility of the produced laminated sheet S3, the total light transmittance was obtained in the same manner as in example 1, and the visibility was examined visually. As a result, the total light transmittance was 78.2%, and the mouth and nose of the face photograph were clearly seen by visual observation although the degree of observation was not achieved through the mask of the transparent film. Fig. 14 is a photograph taken at this time.

Example 4

Using the sheet-like laminated body 4 formed in the same manner as in example 1, a plurality of melt-solidified portions 5 having a shape similar to that shown in fig. 11 were formed on the sheet-like laminated body 4 by an embossing apparatus M2, thereby producing a laminated sheet S4.

The shape of the distal end surface of the convex portion 23a of the embossing roller 23 of the embossing device M2 used in forming the plurality of melt-solidified portions 5 is the same as the shape of the melt-solidified portions 5 shown in fig. 11, and the area ratio is 50%. The surface temperature of the convex portion 23a of the embossing roller 23 at the time of forming the melt-solidified portion 5 was 145 degrees celsius, the surface temperature of the backup roller was 145 degrees celsius, and other processing conditions were the same as in example 1.

In order to evaluate the air permeability and the particle trapping property of the produced laminated sheet S4, a filter performance test was performed in the same manner as in example 1.

As a result of the filter performance test, the pressure loss was 203.2 Pa, and the trapping efficiency was 78.1%.

In addition, regarding the produced laminated sheet S4, in order to evaluate the visibility, the total light transmittance was obtained in the same manner as in example 1, and the visibility was examined visually. As a result, the total light transmittance was 70.7%, and the mouth and nose of the face photograph were clearly seen by visual observation. Fig. 15 is a photograph taken at this time.

Comparative example 1

For comparison with examples 1 to 4, as comparative example 1, a laminate sheet S5 constituting a mask body of a conventional nonwoven sanitary mask ("nonwoven fabric 3-layer mask manufactured by tokyo medical co.) was used. As the laminate sheet S5, a spunbond nonwoven fabric having a weight per unit area of 18 g/square meter and using polypropylene (PP) as a raw material was used as the first base material layer 1, a spunbond nonwoven fabric having a weight per unit area of 18 g/square meter and using polypropylene (PP) as a raw material was used as the third base material layer 3, a meltblown nonwoven fabric having a weight per unit area of 25 g/square meter and using polypropylene (PP) as a raw material was used as the second base material layer 2, and the first base material layer 1, the second base material layer 2, and the third base material layer 3 were overlapped so that the second base material layer 2 was arranged between the first base material layer 1 and the third base material layer 3 to form a laminate sheet S5, and the laminate sheet S5 did not have a plurality of melt-solidified portions 5.

The same filter performance test as in example 1 was performed on the laminated sheet S5.

As a result of the filter performance test, the pressure loss was 102.4 Pa, and the trapping efficiency was 78.4%.

As for laminate S5, the total light transmittance was obtained in the same manner as in example 1, and as a result, the total light transmittance was 30.4%.

In addition, in order to evaluate the visibility, the laminate sheet S5 was examined visually for the visibility by obtaining the total light transmittance in the same manner as in example 1. As a result, the total light transmittance was 30.4%, and the mouth and nose of the face photograph could not be recognized at all by visual observation. Fig. 16 is a photograph taken at this time.

Comparative example 2

For comparison with examples 1 to 4, as comparative example 2, a laminate sheet S6 constituting a mask body of a conventional sanitary mask ("nonwoven fabric 2-layer mask manufactured by tokyo medical co.) was used. The laminate sheet S6 was formed by overlapping 2 sheets of spunbonded nonwoven fabrics each having a weight of 20 g per square meter and using polypropylene (PP) as a raw material, and did not have a filter layer made of a melt-blown nonwoven fabric as in comparative example 1, and also did not have a plurality of melt-cured portions.

Regarding the laminated sheet S6, the same filter performance test as in example 1 was performed.

As a result of the filter performance test, the pressure loss was 6.2 Pa, and the trapping efficiency was 3.1%.

Further, as for laminate S6, the total light transmittance was 56.4% as a result of obtaining the total light transmittance in the same manner as in example 1, and the mouth and nose were seen as a result of visually inspecting the visibility in the same manner as in comparative example 1. Fig. 17 is a photograph taken at this time.

(evaluation)

Table 1 shows various data concerning the production of the laminated sheet and data concerning the air permeability, the particle trapping property, and the visibility obtained by the performance test described above, with respect to examples 1 to 4 and comparative examples 1 to 2.

[ Table 1 ]

The laminate sheets of examples 1 to 4 were compared with comparative examples 1 and 2 for air permeability, particle trapping property, and visibility, and the quality was judged.

(evaluation of air permeability)

As shown in table 1, in examples 1 to 3, the pressure loss value was the same as that of comparative example 1, and therefore, it can be evaluated that the laminated sheets S1, S2, and S3 of examples 1 to 3 had the same degree of ventilation as that of the conventional sanitary mask. Laminate sheet S4 of example 4 had inferior ventilation to comparative example 1.

(evaluation of Capacity)

As shown in table 1, the trapping efficiency of examples 1 to 4 was at a level of 70 to 80%, which is substantially the same as that of comparative example 1, and was 60% or more of the target. Further, the trapping efficiency was far more than 3.1% of that of comparative example 2. Therefore, examples 1 to 4 have air permeability and trapping property for preventing scattering of flying dust such as pollen, saliva and expectoration in the air.

(evaluation of visibility)

As shown in table 1, the total light transmittance of examples 1 to 4 was sufficiently higher than that of comparative examples 1 and 2. In the photograph shown in fig. 16, the mouth and nose cannot be visually recognized at all, whereas in the photograph shown in fig. 17, the mouth and nose can be seen with blurring, and in the photographs shown in fig. 12 to 15, the mouth angle and nose can be sufficiently visually recognized. Therefore, it can be evaluated that the visibility of the laminate sheets S1, S2, S3, S4 of examples 1 to 4 is sufficiently good.

In the laminated sheet S of the present invention, the pressure loss in the filter performance test in which the supply amount of air is set so that the air velocity of the air passing through the laminated sheet S is 20 cm per second is used as an index of the ventilation performance of the laminated sheet S, and the target value of the pressure loss is 300 pascals or less, more preferably 210 pascals or less. In the filter performance test, the number of particles of 0.3 to 0.5 μm contained in the upstream and downstream air is measured by a particle counter, and when the ratio of the difference between the measured number of particles on the upstream side and the number of particles on the downstream side to the number of particles on the upstream side is defined as the collection efficiency, the collection efficiency is used as an index of the collection performance, and the target value of the collection efficiency is 60% or more, more preferably 70% or more. The target value of the total light transmittance, which is an index of transparency, is 70% or more. The target value of the occupied area of the in-frame non-melted portion 6a, which is an index of resolution, is 400 square millimeters or less, and more preferably 40 square millimeters or less. If the occupied area of the melt-solidified portion 5 in the virtual boundary box P is too small, the fibers of the nonwoven fabric cover the melt-solidified portion 5 and the total light transmittance of the laminate is reduced, so that the target value of the occupied area of the melt-solidified portion 5 in the virtual boundary box P is preferably 0.04 square millimeters or more.

Further, 3 kinds of laminated sheets having different shapes and sizes of the melt-solidified portions 5 were produced, and the filter performance and visibility thereof were studied. At this time, the melt-solidified portions 5 were formed on the sheet-like layered body 4 formed in the same manner as in example 2 by the embossing device M2. In order to evaluate the filter performance and visibility of the laminated sheet, the pressure loss, the collection efficiency, and the total light transmittance were obtained in the same manner as in example 1. The area of the distal end face of the convex portion 23a is calculated from the shape and size of the distal end face of the convex portion 23a of the embossing roller 23, the area of the distal end face of the convex portion 23a is set as the occupied area of the melt-solidified portion 5 in the virtual boundary box P, and the area of the virtual boundary box P is calculated from the shape and size of the empty space around the convex portion 23a of the embossing roller 23.

Example 5

The laminate sheet S5 is manufactured by forming a plurality of melt-solidified portions 5 having the shape shown in fig. 18 on the sheet-like laminate 4. The shape of the tip end surface of the convex portion 23a of the embossing roller 23 used at this time was square, the area of the tip end surface was 0.25 square millimeters, and the area of the virtual boundary box P was 1.8 square millimeters. The area of the non-molten portion 6a in the frame was about 1.5 square millimeters, and the area ratio of the molten solidified portion 5 to the area of the virtual boundary frame P was about 14%. Further, as a result of the filter performance test on the laminated sheet S5, the pressure loss was 171.8 pascals, the collection efficiency was 78.3%, and the total light transmittance was 74%. As a result of visual inspection, the mouth and nose of the face photograph were clearly seen, although the face was not observed through the mask of the transparent film. Fig. 19 is a photograph taken at this time.

Example 6

The laminate sheet S6 is manufactured by forming a plurality of melt-solidified portions 5 having the shape shown in fig. 20 on the sheet-like laminate 4. The shape of the tip end surface of the convex portion 23a of the embossing roller 23 used at this time was rectangular, the area of the tip end surface was 0.42 square mm, and the area of the virtual boundary box P was about 2.3 square mm. The area of the non-molten portion 6a in the frame was about 1.9 square millimeters, and the area ratio of the molten solidified portion 5 to the area of the virtual boundary frame P was about 18%. Further, as a result of the filter performance test on the laminated sheet S6, the pressure loss was 206.4 pascals, the collection efficiency was 77%, and the total light transmittance was 74.8%. As a result of visual inspection, the mouth and nose of the face photograph were clearly seen, although the face was not observed through the mask of the transparent film. Fig. 21 is a photograph taken at this time.

Example 7

The laminate sheet S5 is manufactured by forming a plurality of melt-solidified portions 5 having the shape shown in fig. 22 on the sheet-like laminate 4. The shape of the tip end surface of the convex portion 23a of the embossing roller 23 used at this time was square, the area of the tip end surface was 0.04 square millimeters, and the area of the virtual boundary box P was about 0.36 square millimeters. The area of the non-molten portion 6a in the frame was about 0.32 square mm, and the area ratio of the molten solidified portion 5 to the area of the virtual boundary frame P was about 11%. Further, as a result of the filter performance test on the laminated sheet S7, the pressure loss was 198.8 pascals, the collection efficiency was 77.6%, and the total light transmittance was 73.7%. As a result of visual inspection, the mouth and nose of the face photograph were clearly seen, although the face was not observed through the mask of the transparent film. Fig. 23 is a photograph taken at this time.

Table 2 shows various data related to the production of the laminated sheet and data related to the air permeability, the particle trapping property, and the visibility obtained by the performance test described above, with respect to examples 5 to 7.

[ Table 2 ]

The laminates S5, S6 and S7 of examples 5 to 7 each reached the target values of pressure loss, collection efficiency and total light transmittance in the filter performance test, and were suitable in air permeability and transparency.

That is, the target value of the pressure loss was 300 pascals or less, whereas the target value was 171.8 pascals in example 5, 206.4 pascals in example 6, and 198.8 pascals in example 7. The target value of the trapping efficiency was 60% or more, whereas it was 78.3% in example 5, 77% in example 6, and 77.6% in example 7. The total light transmittance was 70% or more, whereas the target value was 74% in example 5, 74.8% in example 6, and 73.7% in example 7. In addition, in regard to visibility, examples 5 to 7 were all considered to have visibility by visual inspection. In contrast, the occupied area of the in-frame non-melted portion 6a was 400 square millimeters or less, which is about 1.6 square millimeters in example 5, about 1.9 square millimeters in example 6, and about 0.32 square millimeters in example 7.

Regarding the laminated sheets S1 to S4 of examples 1 to 4, the area of the top end face of the convex portion 23a was calculated from the shape and size of the top end face of the convex portion 23a of the embossing roller 23, the area of the convex portion 23a was set as the occupied area of the melt-solidified portion 5 in the virtual boundary box P, the area of the virtual boundary box P was calculated from the shape and size of the space around the convex portion 23a of the embossing roller 23, and the area of the in-frame area ratio and the area of the in-frame non-melt portion 6a were calculated from the occupied area of the melt-solidified portion 5 and the area of the virtual boundary box P. As a result, the area of the tip end surface of the convex portion 23a of the embossing roller 23 was 2.6 square millimeters in example 1, 0.6 square millimeters in example 2, 33.2 square millimeters in example 3, 0.7 square millimeters in example 4, the area of the virtual boundary frame P was 12.8 square millimeters in example 1, 2.4 square millimeters in example 2, 63.8 square millimeters in example 3, 1.41 square millimeters in example 4, and the area of the in-frame non-melted portion 6a was about 10.2 square millimeters in example 1, about 1.8 square millimeters in example 2, about 30.6 square millimeters in example 3, and about 0.7 square millimeters in example 4.

The laminate sheets S1 to S4 of examples 1 to 4 were also evaluated in the same manner as in examples 5 to 7. As a result, the laminated sheets S1 to S4 are suitable in air permeability and transparency.

According to the present invention, as the second base material layer 2, a meltblown nonwoven fabric can be used instead of a nanofiber nonwoven fabric. The fiber diameter of the melt-blown nonwoven fabric is approximately 500 nm or more. The sheet-like laminate 4 may be composed of the first base material layer 1 and the second base material layer 2 without the third base material layer 3, or may have 4 or more layers. Instead of the nonwoven fabrics of the first and third base material layers, yarns, woven fabrics, knitted fabrics, and films having air permeability may be used. In the case of a fiber aggregate, the smaller the density, the better. In the case of synthetic fibers, it is preferable that the weight per unit area is low and that no impurities such as a masterbatch are present. Further, a whitening agent such as titanium oxide is not added because it inhibits transparency. The second base material layer 2 may be a nanofiber nonwoven fabric having no melt-cured portion 5, and may be a nonwoven fabric having a plurality of melt-cured portions 5 obtained by embossing the first base material layer 1 and the third base material layer 3. In order to form nanofibers, a substrate to which hydrophilicity is imparted is preferable. The transparent film having the openings may be used as the first base material layer 1 and the third base material layer 3, or may be used as a fourth base material layer provided on the third base material layer 3. In the first base material layer 1, the third base material layer 3, and the like, polyethylene (PE), polylactic acid (PLA), polyester (PET), polypropylene (PP), nylon (NY), PBT, PVA, polyurethane, natural thermoplastic materials, and the like are suitable materials, and in the nanofiber nonwoven fabric or the meltblown nonwoven fabric of the second base material layer, PVDF, cellulose acetate, protein, CNF, PCL, PAI, PVA, PEG, acrylic resin, PAN, and the like may be used in addition to the above.

In fig. 2, the melt-solidified portion 5 extends from the front surface to the back surface of the sheet-like layered body 4, but a part of the vicinity of the back surface of the sheet-like layered body 4 may remain unmelted. Even in this case, if a part that is not melted does not greatly affect the transparency of the laminate sheet S, the melt-solidified portion 5 is regarded as going from the front surface to the back surface of the sheet-like laminate 4. The melt-solidified portion 5 may not be completely transparent, and the non-melt portion 6 may not completely block light.

In addition, although the melt-solidified portions 5 shown in fig. 9 extend in the longitudinal direction and the transverse direction, in the sanitary mask 10 shown in fig. 24, the plurality of melt-solidified portions 5 each extend only in the longitudinal direction. The melt-solidified portion 5 may be elongated only in the lateral direction or only in the oblique direction, if necessary. Fig. 25 shows the sanitary mask 10 shown in fig. 24 with a portion thereof enlarged and a central portion thereof omitted in the longitudinal direction. In fig. 25, a quadrangle surrounded by the points a, b, c, d is a virtual boundary box P, and the length of the long side of the virtual boundary box P is the same as the length of the long side of the melt-solidified portion 5. The plurality of melt-solidified portions 5 extending in the longitudinal direction are each of the same shape and the same size, and are distributed and surrounded by each of a plurality of virtual boundary frames P of the same shape and the same size, which are aligned in a row in the lateral direction and are in contact with each other without gaps, and are uniformly distributed on the surface of the sheet-like laminate 11. In the case where the plurality of melt-solidified portions 5 extend obliquely in parallel, the shape of the virtual boundary box P may be a parallelogram.

The laminate sheet is not limited to the same virtual boundary box and may be uniformly distributed over the entire surface thereof, and for example, one or a plurality of specific patterns may be locally arranged so as to cover a part of the surface portion, and in this case, the specific patterns may be ignored, and the area ratio, the air permeability, the transparency, and the like may be considered with respect to the distribution area of the melt-solidified portion. The sanitary mask may be provided with wrinkles or a specific pattern, and the front and back of the laminate may be used upside down.

Description of the reference numerals

S … laminate

1 … a first substrate layer; 1a … nonwoven fabric

2 … a second substrate layer; 2a … nonwoven fabric

3 … third substrate layer; 3a … nonwoven fabric

4 … sheet laminate

5 … melt-solidified portion

6 … non-molten portion

7 … primary laminate

10 … sanitary mask

11 … mask body

12 … ear hanging part

13 … mouth

14 … nose

21 … guide roller

22 … guide roller

23 … embossing roll; 23a … convex part

24 … support roller

P … virtual bounding box.

Claims (5)

1. A method of making a laminate comprising:

forming a sheet-like laminate having at least a first base layer formed of a plurality of thermoplastic fibers and a second base layer formed of a plurality of thermoplastic fibers finer than the fibers of the first base layer; and

A step of forming a plurality of melt-solidified portions on the sheet-like laminate from the front surface to the back surface of the sheet-like laminate,

it is characterized in that the method comprises the steps of,

the first substrate layer is formed of a nonwoven fabric,

the second base material layer is formed by nonwoven fabric formed by a plurality of nanofibers spun by an electrostatic spinning method,

the total light transmittance of the laminated sheet is 70% or more,

the pressure loss in the filter performance test in which the air supply amount was set so that the air velocity of the air passing through the laminated sheet was 20 cm per second was 300 Pa or less,

in the filter performance test, the number of particles of 0.3 to 0.5 μm contained in the upstream and downstream air is measured by a particle counter, and when the ratio of the difference between the measured number of particles on the upstream side and the number of particles on the downstream side to the number of particles on the upstream side is defined as the collection efficiency, the collection efficiency of the laminated sheet is 60% or more,

the area ratio of the sum of the occupied areas of the plurality of melt-solidified portions to the area of the sheet-like layered body is in a range of 10% to 80%.

2. The method of manufacturing a laminate sheet according to claim 1,

The sheet-like laminate has a third substrate layer made of a nonwoven fabric formed of a plurality of thermoplastic fibers on the side of the second substrate layer opposite to the first substrate layer.

3. The method of manufacturing a laminate sheet according to claim 1,

the plurality of melt-solidified portions are distributed to each of a plurality of virtual boundary frames having the same shape and size and contacting each other without gaps, which are set on the surface of the sheet-like laminated body, and are surrounded by the virtual boundary frames, and are uniformly distributed on the surface of the sheet-like laminated body so that the occupied area of the melt-solidified portions of each virtual boundary frame is the same, and when the portions other than the melt-solidified portions in the virtual boundary frames are defined as in-frame non-melt portions, the area of the in-frame non-melt portions is 400 square millimeters or less.

4. A method for producing a sanitary mask, wherein the sanitary mask having a face covered by the laminate produced by the method for producing a laminate according to claim 1 is used as a mask body.

5. A laminated sheet, characterized in that,

the laminated sheet is provided with:

A sheet-like laminate comprising at least a first base layer made of a nonwoven fabric formed of a plurality of thermoplastic fibers and a second base layer made of a nonwoven fabric formed of a plurality of thermoplastic nanofibers spun by an electrospinning method, the plurality of nanofibers being finer than the fibers of the first base layer; and

a plurality of melt-curing units formed on the sheet-like laminate from the front surface to the back surface thereof, wherein the plurality of melt-curing units adjust the area ratio of the sum of the occupied areas to the area of the sheet-like laminate to obtain desired air permeability and transparency,

the total light transmittance of the laminated sheet is 70% or more,

the pressure loss in the filter performance test in which the air supply amount was set so that the air velocity of the air passing through the laminated sheet was 20 cm per second was 300 Pa or less,

in the filter performance test, the number of particles of 0.3 to 0.5 μm contained in the upstream and downstream air is measured by a particle counter, and when the ratio of the difference between the measured number of particles on the upstream side and the number of particles on the downstream side to the number of particles on the upstream side is defined as the collection efficiency, the collection efficiency of the laminated sheet is 60% or more,

The area ratio of the sum of the occupied areas of the plurality of melt-solidified portions to the area of the sheet-like layered body is in a range of 10% to 80%.

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