Laminate and method for manufacturing a laminate

Abstract

To provide a laminate with excellent shock absorption properties and suitable for recycling, and a method for manufacturing the laminate. [Solution] A laminate 10 comprising a first layer 11 and a second layer located on one surface of the first layer 11 and in contact with the first layer 11, wherein the first layer 11 is an airlaid nonwoven fabric, the second layer is a nonwoven fabric, the first layer 11 and the second layer are joined together, and a plurality of slit-shaped through holes 13 penetrating the first layer 11 and the second layer are provided in a staggered pattern.

Description

Technical Field

[0001] The present invention relates to a laminate and a method for manufacturing the laminate.

Background Art

[0002] As a net for protecting fruits and the like, a buffer material obtained by molding a resin foam sheet into a mesh shape is known. In recent years, from the viewpoints of manufacturing cost and environmental load, a paper buffer material provided with zigzag cuts and becoming mesh-shaped by spreading it out has attracted attention. Patent Document 1 discloses a paper buffer material provided with zigzag cuts in a region other than a bonding region of a laminated paper having a bonding region where longitudinal end edges of a long first paper and a second paper are bonded by an adhesive.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to impart a function to the buffer material, for example, the buffer material may have a laminated structure of two or more layers. In a buffer material having a laminated structure of two or more layers, usually, it is necessary to bond each layer using an adhesive as described in Patent Document 1. However, a buffer material obtained by bonding each layer using an adhesive was inconvenient for recycling. In addition, the buffer material described in Patent Document 1 was inferior in shock absorbency. ​​​​​​​​ The present invention has the following aspects. [1] A laminate comprising a first layer and a second layer located on one surface of the first layer and in contact with the first layer, The first layer is an airlaid nonwoven fabric. The second layer is a nonwoven fabric, The first layer and the second layer are joined together. A laminate in which a plurality of slit-shaped through holes are arranged in a staggered pattern, penetrating the first layer and the second layer. [2] The laminate according to [1], wherein the apparent specific gravity of the second layer is greater than the apparent specific gravity of the first layer. [3] The laminate according to [2], wherein the second layer is one or more selected from airlaid nonwoven fabrics, spunlace nonwoven fabrics and wet-laid nonwoven fabrics. [4] The process includes a joining step for joining the first layer and the second layer, The first layer is an airlaid nonwoven fabric. The second layer is a nonwoven fabric, A method for manufacturing a laminate, wherein the joining step is a step of providing a plurality of slit-shaped through holes that penetrate the first layer and the second layer in a staggered pattern. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a laminate with excellent shock absorption properties and suitable for recycling, as well as a method for manufacturing the laminate. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic plan view showing an example of the laminate of the present invention. [Figure 2] This is a cross-sectional view of the laminate shown in Figure 1, along the line A-A'. [Figure 3] Figure 1 is a plan view showing the laminate stretched in the X direction. [Figure 4] This is a schematic diagram showing an example of a manufacturing apparatus used in the manufacturing method of laminates, and a side view showing its configuration. [Modes for carrying out the invention]

[0009] Hereinafter, an embodiment of the laminate and the method for manufacturing the laminate according to the present invention will be described in detail with reference to Figures 1 to 4 as appropriate. In this specification, a numerical range represented by "~" means a range that includes the numbers before and after the "~" as the lower and upper limits, respectively. For example, A~B is equivalent to A or greater and B or less. Furthermore, the drawings used in the following description may, for convenience, show enlarged versions of key features to make them easier to understand, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc., exemplified in the following description are examples only, and the present invention is not limited to them. It can be implemented with appropriate modifications without changing the essence of the invention. Furthermore, in Figures 2-4, the same reference numerals are used for components identical to those in Figure 1, and their explanations are omitted.

[0010] [Laminated structure] Figures 1-3 show an example of the laminate of the present invention. The laminate 10 of this embodiment comprises a first layer 11 and a second layer 12 located on one surface 11a of the first layer 11 and in contact with the first layer 11. The first layer 11 and the second layer 12 are joined together. Furthermore, the laminate 10 has a plurality of through holes 13.

[0011] <First Layer> The first layer 11 is an airlaid nonwoven fabric (hereinafter also referred to as "nonwoven fabric A"). Because the first layer 11 is made of airlaid nonwoven fabric, the first layer 11 and the second layer 12 are joined together when the through holes 13, described later, are provided. In addition, the presence of the first layer 11, which is airlaid nonwoven fabric, in the laminate 10 improves its shock absorption. Furthermore, since the laminate 10 has multiple through holes 13, it can also be said that the nonwoven fabric A, i.e., the first layer 11, has multiple through holes 13.

[0012] The apparent specific gravity of nonwoven fabric A is 0.2 g / cm³.3 The following is preferable, 0.15 g / cm 3 The following is more preferable, 0.1 g / cm 3 The following is even more preferable, and also 0.01 g / cm 3 The following is preferable, 0.02 g / cm 3 The following is more preferable, 0.03 g / cm 3 The following is even more preferable. If the apparent specific gravity of the nonwoven fabric A is not less than the above lower limit value, it is easier to disperse the impact energy in the plane direction of the laminate 10, and it becomes easier to further suppress damage to the packaged items such as fruits. If the apparent specific gravity of the nonwoven fabric A is not more than the above upper limit value, the laminate 10 is likely to deform and is likely to absorb the impact energy. The above upper and lower limits can be arbitrarily combined. For example, the apparent specific gravity of the nonwoven fabric A is preferably 0.01 to 0.2 g / cm 3 is preferable, 0.02 to 0.15 g / cm 3 is more preferable, 0.03 to 0.1 g / cm 3 is even more preferable. The apparent specific gravity of the nonwoven fabric A is the apparent specific gravity in the state where through holes are formed. The apparent specific gravity of the nonwoven fabric A is the specific gravity obtained by dividing the basis weight of the nonwoven fabric A by the thickness of the nonwoven fabric A, and is also referred to as the apparent density.

[0013] The thickness of the nonwoven fabric A is preferably 0.2 to 3 mm, more preferably 0.4 to 2.5 mm, and even more preferably 0.5 to 2 mm. If the thickness of the nonwoven fabric A is not less than the above lower limit value, the impact is likely to spread inside the nonwoven fabric A, and the impact absorbency and impact mitigation property are further improved. If the thickness of the nonwoven fabric A is not more than the above upper limit value, the overall thickness of the laminate 10 is not likely to become thick, and for example, it becomes easier to package the packaged items. The thickness of the nonwoven fabric A is the thickness in the state where through holes are formed. The thickness of the nonwoven fabric A is the average value of the thickness of the first layer 11 measured from the image obtained by observing the cross section of the laminate 10 under a microscope at any three locations of the laminate 10.

[0014] The basis weight of the nonwoven fabric A is 30 to 200 g / m 2 is preferable, and 35 to 160 g / m 2 is more preferable, and 40 to 120 g / m 2This is even more preferable. If the basis weight of nonwoven fabric A is equal to or greater than the lower limit, the impact absorption is further improved. If the basis weight of nonwoven fabric A is equal to or less than the upper limit, the adhesion between the fibers constituting nonwoven fabric A is improved, and the tensile strength is increased. The basis weight of nonwoven fabric A is the value measured in accordance with JIS P 8124:2011, the value measured in accordance with JIS P 8124:2011 after peeling the first layer 11 from the laminate 10, or the value obtained by subtracting the basis weight of nonwoven fabric B from the basis weight of laminate 10. The basis weight of laminate 10 is the value measured in accordance with JIS P 8124:2011. The basis weight of nonwoven fabric A is the same as that of nonwoven fabric a, which will be described later, and the basis weight does not change depending on whether or not there are through holes.

[0015] The fibers constituting the nonwoven fabric A (hereinafter also referred to as "raw material fibers A") can be appropriately selected from known fibers used as raw material fibers for nonwoven fabrics and are not particularly limited. However, when the laminate 10 is used to package food products containing moisture, such as fruit, hydrophilic fibers are preferred from the viewpoint of absorbing drip and maintaining freshness. As hydrophilic fibers, cellulose fibers are preferred in terms of handling during manufacturing, strength, cost, and environmental friendliness. Cellulosic fibers include, for example, wood pulp made from coniferous or hardwood; mercerized pulp or cross-linked pulp obtained by chemically treating wood pulp; non-wood pulp such as bagasse, kenaf, bamboo, hemp, and cotton (cotton linters, etc.); regenerated cellulose such as rayon and fibril rayon; and semi-synthetic cellulose such as acetate and triacetate. Examples of wood pulp include mechanical pulp such as crushed wood pulp, refiner ground pulp, thermomechanical pulp, and chemothermetic pulp; chemical pulp such as kraft pulp, sulfide pulp, and alkali pulp; and semi-chemical pulp. Among these, bleached coniferous kraft pulp (NBKP) and bleached hardwood kraft pulp (LBKP) are preferred in terms of strength and handling during manufacturing. These cellulosic fibers may be used individually or in combination of two or more types.

[0016] Nonwoven fabric A may contain fibers other than hydrophilic fibers as raw material fiber A. Other types of fibers include natural fibers other than hydrophilic fibers, and fibers made from synthetic resins. Examples of natural fibers other than hydrophilic fibers include animal fibers such as wool (e.g., sheep's wool) and silk, and mineral fibers. Examples of synthetic resin fibers include polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), nylon (registered trademark), polyethylene (PE), polypropylene (PP), and polylactic acid (PLA). In one respect, it is preferable that the synthetic resin fibers do not melt during the heat treatment in the manufacture of the airlaid nonwoven fabric. These other fibers may be used individually or in combination of two or more. However, it is preferable that the amount of animal fibers, mineral fiber paper, and synthetic resin fibers added be limited to a range that allows for recycling as paper.

[0017] The average fiber diameter of the raw material fiber A is preferably 10 to 60 μm, and more preferably 20 to 40 μm. If the average fiber diameter of the raw material fiber A is above the lower limit, neps are less likely to occur when making the airlaid nonwoven fabric, that is, the fibers are less likely to clump together, and a homogeneous laminate 10 can be obtained. If the average fiber diameter of the raw material fiber A is below the upper limit, the nonwoven fabric A can be kept at an appropriate softness, and the packaged item is less likely to be damaged when it comes into contact with the packaged item. The average fiber diameter of raw fiber A is calculated by measuring the fiber diameter of 100 fibers under a microscope and taking the average value of those 100 fibers.

[0018] The average fiber length of the raw material fiber A is preferably 1 to 10 mm, and more preferably 3 to 6 mm. If the average fiber length of the raw material fiber A is above the lower limit, the fibers will intertwine appropriately, providing sufficient strength to the nonwoven fabric A. If the average fiber length of the raw material fiber A is below the upper limit, it is possible to prevent the fibers from excessively intertwining and forming clumps, which would result in an uneven nonwoven fabric A. The average fiber length of raw material fiber A is calculated by measuring the fiber length of 100 fibers under a microscope and taking the average value of those 100 fibers.

[0019] Nonwoven fabric A is an airlaid nonwoven fabric. Airlaid nonwoven fabric is a nonwoven fabric in which a web is formed by the airlaid method, which uses airflow to randomly layer the fibers that make up the nonwoven fabric in three dimensions. Airlaid nonwoven fabrics are manufactured, for example, as follows: First, an air-laid web forming device is used to directly deposit raw fibers onto a mesh-like endless belt while dispersing them in the air to form a web. Alternatively, a permeable carrier sheet is placed on the endless belt, and a web is formed on the permeable carrier sheet using an air-laid web forming device while dispersing the raw fibers in the air to form a web. Next, the raw material fibers contained in the web are bonded together to obtain an airlaid nonwoven fabric. Methods for bonding the raw material fibers include the latex bonding method, the thermal bonding method, and the multi-bonding method, which combines the latex bonding method and the thermal bonding method. The latex bonding method involves spraying a binder onto the web, drying it with hot air, etc., and bonding the fibers together. The thermal bonding method involves supplying heat-fusible resin particles or heat-fusible fibers together with the raw material fibers, and heat-treating them with hot air, etc., to heat-bond them. Since the nonwoven fabric produced by the latex bonding method is easily soluble in water and easily recycled as paper, the latex bonding method is preferred as a method for bonding the raw material fibers from the viewpoint of further improving the recyclability of the laminate 10. In other words, nonwoven fabric A may contain, as needed, one or more of the following: a binder, a heat-fusible resin, and a heat-fusible fiber, in addition to the raw material fiber A.

[0020] As a binder, a water-based binder is preferred from the viewpoint of further enhancing the recyclability of the laminate 10. Examples of aqueous binders include water-soluble binders such as casein, sodium alginate, hydroxyethylcellulose, sodium carboxymethylcellulose, polyvinyl alcohol (PVA), and sodium polyacrylate; and emulsion-type binders such as polyacrylic acid esters, acrylic acid ester-styrene copolymers, polyvinyl acetate, ethylene-vinyl acetate copolymer (EVA), acrylonitrile-butadiene copolymers, methyl methacrylate-butadiene copolymers, and styrene-butadiene copolymer latex (SBR). Among these, water-soluble binders, especially water-soluble binders that are difficult or impossible to crosslink with heat, are particularly preferred as aqueous binders because they can be easily separated from the raw material fibers A by dissolving them in water when recycling the laminate 10. Examples of water-soluble binders that are difficult or impossible to crosslink with heat include sodium carboxymethylcellulose and polyvinyl alcohol (PVA).

[0021] The first layer 11 may be a single layer or a multilayer (multi-layer) structure. That is, the first layer 11 may be composed of one layer of nonwoven fabric A or two or more layers of nonwoven fabric A. However, from the viewpoint of making the overall thickness of the laminate 10 less likely to increase, for example, making it easier to pack the items to be packaged, it is preferable that the first layer 11 is composed of one layer of nonwoven fabric A.

[0022] <Second Layer> The second layer 12 is located on one surface 11a of the first layer 11 and is in contact with the first layer 11. In other words, the second layer 12 is laminated adjacent to one surface 11a of the first layer 11. The second layer 12 is responsible for the strength of the laminate 10. By laminating the second layer 12, the tensile strength and tear strength required for packaging are obtained. The second layer 12 is a nonwoven fabric (hereinafter also referred to as "nonwoven fabric B"). Furthermore, since the laminate 10 has multiple through holes 13, it can also be said that the nonwoven fabric B, i.e., the second layer 12, also has multiple through holes 13.

[0023] The apparent specific gravity of nonwoven fabric B is 0.03 g / cm³. 3 The above is preferable, and 0.05 g / cm³ 3 The above is more preferable, 0.06 g / cm³ 3 The above is even more preferable, and also 1.2 g / cm³. 3 The following is preferable: 1.1 g / cm³ 3 The following is more preferable: 1.0 g / cm³ 3 The following is even more preferable: If the apparent specific gravity of nonwoven fabric B is equal to or greater than the lower limit, good strength can be maintained when the laminate 10 is stretched and the through-holes 13 are widened. If the apparent specific gravity of nonwoven fabric B is equal to or less than the upper limit, good workability can be obtained when packaging the items to be packaged. The above upper and lower limits can be combined in any way. For example, the apparent specific gravity of nonwoven fabric B is 0.03 to 1.2 g / cm³. 3 Preferably, 0.05 to 1.1 g / cm³ 3 More preferably, 0.06 to 1.0 g / cm³ 3 That is even more preferable. The apparent specific gravity of nonwoven fabric B is the apparent specific gravity when through-holes are formed. The apparent specific gravity of nonwoven fabric B is the specific gravity obtained by dividing the basis weight of nonwoven fabric B by the thickness of nonwoven fabric B, and is also called the apparent density.

[0024] The apparent specific gravity of the second layer, i.e., the apparent specific gravity of nonwoven fabric B, is preferably equal to or greater than the apparent specific gravity of the first layer 11, i.e., the apparent specific gravity of nonwoven fabric A, and it is more preferable that the apparent specific gravity of nonwoven fabric B is greater than the apparent specific gravity of nonwoven fabric A. Specifically, the difference between the apparent specific gravity of nonwoven fabric B and the apparent specific gravity of nonwoven fabric A (apparent specific gravity of nonwoven fabric B - apparent specific gravity of nonwoven fabric A) is 0.05 g / cm³. 3 The above is preferable, and 0.10 g / cm³ 3 The above is preferable. Because the apparent specific gravity of nonwoven fabric B is greater than that of nonwoven fabric A, the necessary strength for packaging is more easily obtained. In addition, when an impact is applied to the package, the impact is dispersed, making it easier to prevent damage to the packaged items.

[0025] The thickness of nonwoven fabric B is preferably 0.05 to 3 mm, more preferably 0.08 to 2.0 mm, and even more preferably 0.1 to 1.0 mm. If the thickness of nonwoven fabric B is equal to or greater than the lower limit, the through holes 13 allow the fibers of nonwoven fabric A and nonwoven fabric B to intertwine easily, and the first layer 11 and the second layer 12 can be bonded together without the use of adhesive. If the thickness of nonwoven fabric B is equal to or less than the upper limit, the overall thickness of the laminate 10 does not tend to increase, making it easier to package items, for example. The thickness of nonwoven fabric B is the thickness when through holes are formed. The thickness of nonwoven fabric B is the average value of the thickness of the second layer 12 measured from images obtained by microscopically observing the cross-section of the laminate 10 at any three locations on the laminate 10.

[0026] The basis weight of nonwoven fabric B is 10-300 g / m². 2 Preferably, 20-200 g / m 2 More preferably, 30-150 g / m 2 This is even more preferable. If the basis weight of nonwoven fabric B is equal to or greater than the lower limit, sufficient strength can be maintained. If the basis weight of nonwoven fabric B is equal to or less than the upper limit, good workability can be obtained when packaging the items to be packaged. The basis weight of nonwoven fabric B is the value measured in accordance with JIS P 8124:2011 after peeling the second layer 12 from the laminate 10, or the value obtained by subtracting the basis weight of nonwoven fabric A from the basis weight of laminate 10. The basis weight of nonwoven fabric B is the same as that of nonwoven fabric b described later, and the basis weight does not change depending on whether or not there are through holes.

[0027] The fibers constituting nonwoven fabric B (hereinafter also referred to as "raw material fibers B") can be appropriately selected from known fibers used as raw material fibers for nonwoven fabrics and are not particularly limited, but from the viewpoint of water absorption, hydrophilic fibers are preferred. Examples of hydrophilic fibers include the hydrophilic fibers exemplified earlier in the description of the first layer 11. Nonwoven fabric B may contain fibers other than hydrophilic fibers as raw material fibers B. Examples of other fibers include those previously exemplified in the description of the first layer 11.

[0028] The average fiber diameter of the raw material fiber B is preferably 5 to 100 μm, and more preferably 10 to 50 μm. If the average fiber diameter of the raw material fiber B is above the lower limit, the laminate 10 can be given good strength as a cushioning material. If the average fiber diameter of the raw material fiber B is below the upper limit, the laminate 10 is given appropriate rigidity, making it easier to pack the items to be packaged. The average fiber diameter of raw material fiber B is calculated using the same method as the average fiber diameter of raw material fiber A.

[0029] The raw material fiber B is preferably a short fiber with an average fiber length of 3 to 80 mm. If the average fiber length of the raw material fiber B is equal to or greater than the lower limit, good strength can be imparted to the laminate 10 as a cushioning material. When raw material fiber B is a short fiber, the average fiber length is calculated using the same method as the average fiber length of raw material fiber A.

[0030] Examples of nonwoven fabric B include dry nonwoven fabrics such as airlaid nonwoven fabrics and spunlace nonwoven fabrics; and wet nonwoven fabrics. In other words, the second layer 12 is preferably one or more selected from airlaid nonwoven fabrics, spunlace nonwoven fabrics, and wet nonwoven fabrics. Among these, airlaid nonwoven fabrics and wet nonwoven fabrics are preferred as nonwoven fabric B from the viewpoint of being environmentally friendly because they can use natural fibers as the main component. In this invention, the wet-laid nonwoven fabric also includes papers such as tissue paper, kraft paper, and crepe paper, in which the fibers are bonded together by at least one of a binder and hydrogen bonds. From the viewpoint of improving the recyclability of the laminate 10, it is preferable to use an airlaid nonwoven fabric, spunlace nonwoven fabric, or wet-laid nonwoven fabric to bond the raw material fibers B using a hydrolyzable adhesive that does not easily crosslink or does not undergo thermal crosslinking, or without using an adhesive. Among these, airlaid nonwoven fabric is particularly preferable from the viewpoint of improving its performance as a cushioning material.

[0031] An example of an airlaid nonwoven fabric is nonwoven fabric A, which was previously exemplified in the description of the first layer 11. Spunlace nonwoven fabric is a nonwoven fabric in which opened raw fibers are formed into a web using a carding machine or air random machine, and the fibers of the web are three-dimensionally entangled using a high-pressure water flow method. Wet-laid nonwoven fabrics are nonwoven fabrics in which raw fibers are dispersed in water to form a slurry, which is then formed into a web using a wet papermaking method, and the raw fibers contained within the web are bonded together. Methods for bonding the raw fibers include the latex bonding method, thermal bonding method, multi-bonding method (a combination of latex bonding and thermal bonding), water entanglement method, and hydrogen bonding method of pulp.

[0032] Nonwoven fabric B may, in addition to raw material fibers B, optionally contain one or more of the following: a binder, a heat-fusible resin, and a heat-fusible fiber. Examples of these binders, heat-fusible resins, and heat-fusible fibers include those exemplified earlier in the description of the first layer 11.

[0033] The second layer 12 may be a single layer or a multilayer (multi-layer) structure. That is, the second layer 12 may be composed of one layer of nonwoven fabric B or two or more layers of nonwoven fabric B. However, from the viewpoint of making the overall thickness of the laminate 10 less likely to increase, for example, making it easier to package the items to be packaged, it is preferable that the second layer 12 is composed of one layer of nonwoven fabric B.

[0034] An example of a combination of nonwoven fabric A and nonwoven fabric B is shown below. • A combination in which nonwoven fabric A is an airlaid nonwoven fabric and nonwoven fabric B is a wet-laid nonwoven fabric (including paper such as tissue paper, kraft paper, and crepe paper). A combination in which nonwoven fabric A is an airlaid nonwoven fabric, and nonwoven fabric B is an airlaid nonwoven fabric with a higher apparent specific gravity than nonwoven fabric A. • A combination where nonwoven fabric A is an airlaid nonwoven fabric and nonwoven fabric B is a spunlace nonwoven fabric.

[0035] In the above combination of nonwoven fabric A and nonwoven fabric B, it is preferable that nonwoven fabric B is either an airlaid nonwoven fabric or a wet-laid nonwoven fabric due to its high recyclability. Furthermore, since nonwoven fabrics A and B have high recyclability and low environmental impact, it is preferable that they be mainly composed of pulp fibers.

[0036] <Through hole> The through-hole 13 is a slit-shaped cut that penetrates the first layer 11 and the second layer 12. As shown in Figure 1, in a plan view, when the direction parallel to a pair of sides of the laminate 10 is defined as the X direction and the direction perpendicular to the X direction is defined as the Y direction, the through holes 13 are arranged in a staggered pattern, and the longitudinal direction of the through holes 13 is the Y direction. Here, "staggered" refers to an arrangement where multiple rows of through holes 13 are arranged at equal intervals in the Y direction, and these rows are arranged at equal intervals in the X direction, and in two adjacent rows in the X direction, the closest through holes 13 are offset from each other. Preferably, the through holes 13 are offset by half a pitch.

[0037] Since the first layer 11 is an airlaid nonwoven fabric (nonwoven fabric A), the first layer 11 and the second layer 12 are joined together by forming through holes 13 without the need for adhesive. Furthermore, because the laminate 10 has through holes 13, when the laminate 10 is stretched in the X direction, the through holes 13 are expanded into a rhombus or tortoiseshell shape, as shown in Figure 3, resulting in a mesh-like laminate 10. This mesh-like laminate 10 is also called an expanded metal laminate. The laminated body 10 forms a mesh-like structure, and the resulting uneven surface improves its shock absorption.

[0038] The length L of the through-hole 13 is preferably 4 to 30 mm, more preferably 6 to 20 mm, and even more preferably 8 to 15 mm. If the length L is greater than or equal to the lower limit, the opening performance when stretching the laminate 10 to widen the through-hole 13 is excellent. If the length L is less than or equal to the upper limit, the opening spacing when stretching the laminate 10 to widen the through-hole 13 does not become too wide, and good cushioning properties as a packaging material can be maintained. The length L is a value measured using a caliper.

[0039] In a row of through holes 13 arranged at equal intervals in the Y direction, the distance D between adjacent through holes 13 (i.e., the length of the area where no through holes 13 are formed) is preferably 0.5 to 20 mm, more preferably 1 to 10 mm, and even more preferably 1.5 to 5 mm. If the distance D is greater than or equal to the lower limit, the laminate 10 is less likely to tear when the laminate 10 is stretched to widen the through holes 13. If the distance D is less than or equal to the upper limit, the laminate 10 is more likely to develop irregularities when the laminate 10 is stretched to widen the through holes 13, thus maintaining good cushioning properties. The distance D is a value measured using a caliper.

[0040] The width W of a row of adjacent through-holes 13 in the X direction is preferably 0.5 to 20 mm, more preferably 1 to 10 mm, and even more preferably 1.5 to 5 mm. If the width W is greater than or equal to the lower limit, the laminate 10 is less likely to tear when stretched to widen the through-holes 13. If the width W is less than or equal to the upper limit, when the laminate 10 is stretched to widen the through-holes 13, irregularities are more likely to appear, and good cushioning properties can be maintained. The width W is a value measured using calipers.

[0041] <Laminate thickness> The thickness of the laminate 10 is preferably 0.2 to 4 mm, more preferably 0.4 to 3 mm, and even more preferably 0.5 to 2.5 mm. If the thickness of the laminate 10 is above the lower limit, the impact spreads more easily inside the laminate 10, further improving the impact absorption and impact mitigation properties. If the thickness of the laminate 10 is below the upper limit, for example, it becomes easier to package the items to be packaged. The thickness of the laminate 10 is the average value of the thickness of the laminate 10 measured from images obtained by microscopically observing the cross-section of the laminate 10 at any three locations on the laminate 10.

[0042] <Basis weight of laminated material> The basis weight of laminate 10 is 60-300 g / m². 2Preferably, 80-250 g / m² 2 More preferably, 100-200 g / m 2 This is even more preferable. If the basis weight of the laminate 10 is above the lower limit, it offers a better balance between shock absorption and strength. If the basis weight of the laminate 10 is below the upper limit, it maintains strength while providing good workability when packaging the items to be packaged. The basis weight of laminate 10 is the sum of the basis weight of nonwoven fabric A and the basis weight of nonwoven fabric B.

[0043] <Method for manufacturing laminates> The manufacturing method of the laminate 10 of this embodiment includes a step of joining a first layer 11 and a second layer 12 (hereinafter also referred to as the "joining step"), the joining step being a step of providing a plurality of slit-shaped through holes 13 that penetrate the first layer 11 and the second layer 12 in a staggered pattern. In the joining process of this embodiment, nonwoven fabrics a and b, described later, are used and joined together so that nonwoven fabric a becomes the first layer 11 (i.e., nonwoven fabric A) and nonwoven fabric b becomes the second layer 12 (i.e., nonwoven fabric B). The laminate 10 can be manufactured using this method, for example, with the manufacturing apparatus 20 shown in Figure 4.

[0044] (manufacturing equipment) The laminate manufacturing apparatus 20 shown in Figure 4 comprises, in order from downstream, a lamination means 21, a slitting means 22, and a cutting means 23. The lamination means 21 and the slitting means 22 together are also referred to as the joining mechanism.

[0045] The lamination means 21 is a means of obtaining an intermediate 14 by laminating a nonwoven fabric a which will be the first layer and a nonwoven fabric b which will be the second layer. The lamination means 21 includes a first feed roll 211 for feeding out a long nonwoven fabric a wound into a roll, a second feed roll 212 for feeding out a long nonwoven fabric b wound into a roll, and a plurality of guide rolls 213.

[0046] The first feed roll 211 has nonwoven fabric a wound around it. The second feed roll 212 has nonwoven fabric b wound around it. Furthermore, the first feed roll 211 and the second feed roll 212 are each connected to a drive device (not shown) such as a motor and rotated, thereby enabling the nonwoven fabric a wound around the first feed roll 211 and the nonwoven fabric b wound around the second feed roll 212 to be unwound (fed out) at a predetermined speed.

[0047] Multiple guide rolls 213 are arranged between the first feed roll 211 or the second feed roll 212 and the slitting means 22, that is, on the transport route of nonwoven fabric a and nonwoven fabric b to the slitting means 22, to transport nonwoven fabric a and nonwoven fabric b without slack. In this embodiment, four guide rolls 213 are arranged, and the nonwoven fabric a is laminated onto the nonwoven fabric b by the third guide roll 213 from the downstream side to obtain an intermediate product 14. These guide rolls 213 are configured to rotate freely and rotate as nonwoven fabrics a and b move. The guide roll 213 may be configured to be connected to a drive device such as a motor and rotated, as needed.

[0048] The slitting means 22 is a means of slitting the intermediate body 14 to create through holes that penetrate the nonwoven fabric a and nonwoven fabric b. The slitting means 22 includes a slit roll 221 having slitting blades (not shown) on its circumferential surface, and a nip roll 222 positioned opposite the slit roll 221 and sandwiching the intermediate body 14 together with the slit roll 221.

[0049] The slit roll 221 is equipped with multiple slitting blades (not shown) on its outer surface. Multiple slitting blades are arranged in a staggered pattern on the outer circumferential surface of the slitting roll 221 such that the through holes provided in the intermediate body 14 are arranged in a staggered pattern, with the longitudinal direction of the through holes parallel to the conveying direction of the intermediate body 14. The slit roll 221 is connected to a drive device such as a motor (not shown) and rotated.

[0050] The Nip Roll 222 is a roll with a flat surface. The nip roll 222 rotates in sync with the slit roll 221 while being pressed against the slit roll 221 with a predetermined pressing force via the intermediate body 14. Furthermore, the nip roll 222 may be connected to a drive device (not shown) such as a motor so as to rotate in sync with the slit roll 221.

[0051] The cutting means 23 is a means for cutting the strip-shaped laminate 10, which has through holes, to a desired size to obtain a single-sheet laminate 10. The cutting means 23 includes a cutting machine 231. The cutting machine 231 is not particularly limited as long as it is capable of cutting the laminate 10, but examples include a cutting machine.

[0052] (Nonwoven fabric a) Nonwoven fabric a becomes the first layer 11, i.e., nonwoven fabric A, of the laminate 10 through a bonding process. Nonwoven fabric a is an airlaid nonwoven fabric, and no through-holes are formed in nonwoven fabric a before it is joined with nonwoven fabric b.

[0053] The apparent specific gravity of nonwoven fabric a is 0.2 g / cm³. 3 The following is preferable: 0.15 g / cm³ 3 The following is more preferable: 0.1 g / cm³ 3 The following is even more preferable, and also 0.01 g / cm³ 3 The above is preferable, and 0.02 g / cm³ 3 The above is more preferable, 0.03 g / cm³ 3 The above is even more preferable. If the apparent specific gravity of nonwoven fabric a is above the lower limit, it is easier to obtain a laminate 10 that can easily disperse impact energy in the planar direction, and damage to the packaged goods can be further suppressed. If the apparent specific gravity of nonwoven fabric a is below the upper limit, it is easier to obtain a laminate 10 that is easily deformable and can easily absorb impact energy. The above upper and lower limits can be combined arbitrarily. For example, the apparent specific gravity of nonwoven fabric a is 0.01 to 0.2 g / cm³. 3 Preferably, 0.02 to 0.15 g / cm³ 3 More preferably, 0.03 to 0.1 g / cm³ 3 That is even more preferable. The apparent specific gravity of nonwoven fabric a is the specific gravity obtained by dividing the basis weight of nonwoven fabric a by the thickness of nonwoven fabric a, and is also called the apparent density.

[0054] The thickness of the nonwoven fabric a is preferably 0.2 to 3 mm, more preferably 0.4 to 2.5 mm, and even more preferably 0.5 to 2 mm. If the thickness of the nonwoven fabric a is below the above upper limit, it is easier to obtain a laminate 10 with improved shock absorption and shock mitigation properties. If the thickness of the nonwoven fabric a is below the above upper limit, the overall thickness of the laminate 10 does not tend to increase, making it easier to package items, for example. The thickness of nonwoven fabric a is a value measured in accordance with JIS L 1913:2010.

[0055] The basis weight of nonwoven fabric a is 30-200 g / m². 2 Preferably, 35-160 g / m² 2 More preferably, 40-120 g / m 2 This is even more preferable. If the basis weight of the nonwoven fabric a is equal to or greater than the lower limit, a laminate 10 with superior shock absorption is more likely to be obtained. If the basis weight of the nonwoven fabric a is equal to or less than the upper limit, the adhesion between the fibers constituting the nonwoven fabric a is improved, and the tensile strength is increased. The basis weight of nonwoven fabric a is a value measured in accordance with JIS L 1913:2010.

[0056] The fibers that make up nonwoven fabric a include the raw material fiber A, which was previously exemplified in the description of nonwoven fabric A. Nonwoven fabrics produced by the latex bonding method are easily soluble in water and easily recycled as paper. Therefore, from the viewpoint of further improving the recyclability of the laminate 10, nonwoven fabrics obtained by the latex bonding method are preferred as nonwoven fabric a.

[0057] One sheet of nonwoven fabric a may be used, or two or more sheets of nonwoven fabric a may be used. However, it is preferable to use one sheet of nonwoven fabric a because the overall thickness of the laminate 10 does not tend to increase, and for example, it becomes easier to pack the items to be packaged.

[0058] (Non-woven fabric b) Nonwoven fabric b becomes the second layer 12, or nonwoven fabric B, of the laminate 10 through a bonding process. Nonwoven fabric b does not have through holes formed in it before it is joined to nonwoven fabric a.

[0059] The apparent specific gravity of nonwoven fabric b is 0.03 g / cm³. 3 The above is preferable, and 0.05 g / cm³ 3 The above is more preferable, 0.06 g / cm³ 3 The above is even more preferable, and also 1.2 g / cm³. 3 The following is preferable: 1.1 g / cm³ 3 The following is more preferable: 1.0 g / cm³ 3 The following is even more preferable: If the apparent specific gravity of nonwoven fabric b is equal to or greater than the lower limit, good strength can be maintained even when the laminate 10 is stretched to widen the through holes 13 after the through holes 13 have been made. If the apparent specific gravity of nonwoven fabric b is equal to or less than the upper limit, it is easier to obtain a laminate 10 that has good workability when packaging the items to be packaged. The above upper and lower limits can be combined in any way. For example, the apparent specific gravity of nonwoven fabric b is 0.03 to 1.2 g / cm³. 3 Preferably, 0.05 to 1.1 g / cm³ 3 More preferably, 0.06 to 1.0 g / cm³ 3 That is even more preferable. The apparent specific gravity of nonwoven fabric b is the specific gravity obtained by dividing the basis weight of nonwoven fabric b by the thickness of nonwoven fabric b, and is also called the apparent density.

[0060] The apparent specific gravity of nonwoven fabric b is preferably equal to or greater than that of nonwoven fabric a, and more preferably greater than that of nonwoven fabric a. Specifically, the difference between the apparent specific gravity of nonwoven fabric b and nonwoven fabric a (apparent specific gravity of nonwoven fabric b - apparent specific gravity of nonwoven fabric a) is 0.05 g / cm³. 3 The above is preferable, and 0.10 g / cm³ 3 The above is preferable. Because the apparent specific gravity of nonwoven fabric b is greater than that of nonwoven fabric a, the necessary strength for packaging is more easily obtained. In addition, when an impact is applied to the package, the impact is dispersed, making it easier to prevent damage to the packaged items.

[0061] The thickness of nonwoven fabric b is preferably 0.05 to 3 mm, more preferably 0.08 to 2.0 mm, and even more preferably 0.1 to 1.0 mm. If the thickness of nonwoven fabric b is equal to or greater than the lower limit, the fibers of nonwoven fabric a and nonwoven fabric b will intertwine easily when joined together, allowing nonwoven fabric a and nonwoven fabric b to be bonded together without the use of adhesive. If the thickness of nonwoven fabric b is equal to or less than the upper limit, the overall thickness of the laminate 10 will not increase significantly, making it easier to package items, for example. The thickness of nonwoven fabric b is measured according to JIS L 1913:2010.

[0062] The basis weight of nonwoven fabric b is 10-300 g / m². 2 Preferably, 20-250 g / m² 2 More preferably, 30-150 g / m 2 This is even more preferable. If the basis weight of nonwoven fabric b is equal to or greater than the lower limit, a laminate 10 with excellent strength is easily obtained. If the basis weight of nonwoven fabric b is equal to or less than the upper limit, a laminate 10 with good workability when packaging the items to be packaged is easily obtained. The basis weight of nonwoven fabric b is a value measured in accordance with JIS L 1913:2010.

[0063] The fibers constituting nonwoven fabric b include the raw material fiber B, which was previously exemplified in the description of nonwoven fabric B. Examples of nonwoven fabric b include dry nonwoven fabrics such as airlaid nonwoven fabrics and spunlace nonwoven fabrics; and wet nonwoven fabrics. In other words, it is preferable that nonwoven fabric b is one or more selected from airlaid nonwoven fabrics, spunlace nonwoven fabrics, and wet nonwoven fabrics. Among these, airlaid nonwoven fabrics and wet nonwoven fabrics are preferred as nonwoven fabric b from the viewpoint of environmental friendliness because they can use natural fibers as the main component. From the viewpoint of improving the recyclability of the laminate 10, it is preferable to use an airlaid nonwoven fabric, spunlace nonwoven fabric, or wet-laid nonwoven fabric to bond the raw material fibers B using a hydrolyzable adhesive that does not easily crosslink or does not undergo thermal crosslinking, or without using an adhesive. Among these, airlaid nonwoven fabric is particularly preferable from the viewpoint of improving the strength as a cushioning material.

[0064] One sheet of nonwoven fabric b may be used, or two or more sheets of nonwoven fabric b may be used. However, it is preferable to use one sheet of nonwoven fabric b because the overall thickness of the laminate 10 does not tend to increase, and for example, it becomes easier to pack the items to be packaged.

[0065] An example of a combination of nonwoven fabric a and nonwoven fabric b is shown below. • A combination in which nonwoven fabric a is an airlaid nonwoven fabric and nonwoven fabric b is a wet-laid nonwoven fabric (including paper such as tissue paper, kraft paper, and crepe paper). A combination in which nonwoven fabric a is an airlaid nonwoven fabric, and nonwoven fabric b is an airlaid nonwoven fabric with a higher apparent specific gravity than nonwoven fabric a. • A combination in which nonwoven fabric a is an airlaid nonwoven fabric and nonwoven fabric b is a spunlace nonwoven fabric.

[0066] In the above combination of nonwoven fabric a and nonwoven fabric b, it is preferable that nonwoven fabric b is either an airlaid nonwoven fabric or a wet-laid nonwoven fabric due to its high recyclability. Furthermore, since nonwoven fabrics a and b have high recyclability and low environmental impact, it is preferable that they be mainly composed of pulp fibers.

[0067] The following describes an example of a method for manufacturing the laminate 10 using the manufacturing apparatus 20. The manufacturing method of the laminate according to this embodiment comprises the following joining step and cutting step.

[0068] (Joining process) In the joining process, first, nonwoven fabric a and nonwoven fabric b are laminated to obtain an intermediate 14 (hereinafter, this process will also be specifically referred to as the "lamination process"). Specifically, the nonwoven fabric a fed from the first feed roll 211 is laminated onto the nonwoven fabric b fed separately from the second feed roll 212 to obtain an intermediate product 14.

[0069] Next, the intermediate material 14 is transported to the slitting means 22 and supplied between the slitting roll 221 and the nip roll 222. As the intermediate material 14 supplied between the slitting roll 221 and the nip roll 222 passes between them, the slitting blades provided on the slitting roll 221 create multiple slit-shaped through-holes that penetrate the nonwoven fabric a and nonwoven fabric b, forming a staggered pattern such that the longitudinal direction of the through-holes is parallel to the transport direction of the intermediate material 14 (hereinafter, this process will also be specifically referred to as the "slitting process"). Since nonwoven fabric a is an airlaid nonwoven fabric, through-holes are formed and nonwoven fabric a and nonwoven fabric b are joined together without the use of adhesive, so that nonwoven fabric a becomes the first layer, i.e., nonwoven fabric A, and nonwoven fabric b becomes the second layer, i.e., nonwoven fabric B. In this way, through holes are provided, and a strip-shaped laminate 10 is obtained in which a first layer, which is nonwoven fabric A, and a second layer, which is nonwoven fabric B, are joined together.

[0070] The inter-roll pressure between the slit roll 221 and the nip roll 222 when forming through holes is preferably 0.5 to 50 MPa, more preferably 1 to 30 MPa, and even more preferably 5 to 20 MPa. If the inter-roll pressure is above the lower limit, the processed nonwoven fabrics, i.e., nonwoven fabric A and nonwoven fabric B, can be opened well. If the inter-roll pressure is below the upper limit, excessive crushing of nonwoven fabrics a and b can be suppressed.

[0071] Furthermore, if through holes are provided in the intermediate body 14, the laminate 10 may experience thickness reduction due to the pressure (pressure between rolls) applied when stacking nonwoven fabric a and nonwoven fabric b and slitting them. In other words, the actual thickness of the laminate 10 may be thinner than the calculated thickness, which is the sum of the thickness of nonwoven fabric a and the thickness of nonwoven fabric b. Furthermore, the pressure applied when stacking nonwoven fabric a and nonwoven fabric b and slitting them can cause thickness reduction in both nonwoven fabric a and nonwoven fabric b. In other words, after passing through the slitting means 22, the thickness of nonwoven fabric a becomes thinner than before, and as a result, its apparent specific gravity may increase. Therefore, although nonwoven fabric a becomes the first layer, i.e., nonwoven fabric A, after going through the joining process, the apparent specific gravity of nonwoven fabric A may be greater than that of nonwoven fabric a. Similarly, with nonwoven fabric b, although nonwoven fabric b becomes the second layer, i.e., nonwoven fabric B, after going through the joining process, the apparent specific gravity of nonwoven fabric B may be greater than that of nonwoven fabric b.

[0072] In this embodiment of the manufacturing method, the intermediate body 14 is transported to the slitting means 22 so that the nonwoven fabric a and the slit roll 221 are in contact, and cuts (through holes) are made from the nonwoven fabric a side. However, nonwoven fabric a and nonwoven fabric b may be swapped. That is, nonwoven fabric b may be laminated on nonwoven fabric a, and the intermediate body 14 may be transported to the slitting means 22 so that the nonwoven fabric b and the slit roll 221 are in contact, and cuts (through holes) may be made from the nonwoven fabric b side. However, from the viewpoint of making it easier for the fibers of nonwoven fabric a and nonwoven fabric b to intertwine and for nonwoven fabric a and nonwoven fabric b to be joined together, it is preferable to bring nonwoven fabric a into contact with the slit roll 221 and make cuts (through holes) from the nonwoven fabric a side.

[0073] (cutting process) The cutting process involves cutting the strip-shaped laminate 10, which has through holes, to a desired size. Specifically, a strip-shaped laminate 10 with through holes is transported to a cutting means 23. The strip-shaped laminate 10 transported to the cutting means 23 is cut by a cutting machine 231 in a direction perpendicular to the transport direction of the strip-shaped laminate 10 (also called the "width direction of the laminate 10") to the desired size, thereby obtaining a single-sheet laminate 10. In this way, a laminate 10 is obtained in which the first layer 11 and the second layer 12 are joined together, and a plurality of slit-shaped through holes 13 are arranged in a staggered pattern, penetrating the first layer 11 and the second layer 12, as shown in Figures 1 and 2.

[0074] <Effects and Effects> In the laminate of this embodiment described above, an airlaid nonwoven fabric (nonwoven fabric A) is used for the first layer, and through holes are arranged in a staggered pattern that penetrate this first layer and the second layer which is laminated adjacent to the first layer, so that the first layer and the second layer are joined together without the use of adhesive. The laminate of this embodiment is suitable for recycling because it does not have an adhesive layer to bond the first and second layers. In particular, if the first layer, nonwoven fabric A, is an airlaid nonwoven fabric in which raw material fibers A are bonded with a water-soluble binder that does not easily or does not undergo thermal crosslinking, and the second layer, nonwoven fabric B, is an airlaid nonwoven fabric, needle-punched nonwoven fabric, or wet-laid nonwoven fabric in which raw material fibers B are bonded using or without an adhesive, then the laminate can be easily recycled as is without separating the first and second layers. If one of nonwoven fabrics A and B is a nonwoven fabric in which raw material fibers are bonded using an adhesive, or a thermal-bonded nonwoven fabric, then the first and second layers should be separated and recycled separately. The first and second layers are joined to the extent that they do not peel off unintentionally by forming through holes, but they can be easily separated with light force when necessary. Furthermore, since the laminate of this embodiment includes a first layer which is an airlaid nonwoven fabric, it also has excellent shock absorption properties.

[0075] <Application> The laminate of the present invention is suitable as a packaging material such as a cushioning material. When using the laminate of the present invention as a cushioning material, the laminate is stretched as described above to widen the through holes into a rhombus or tortoiseshell shape, and then used as a mesh-like laminate 10 as shown in Figure 3. There are no particular restrictions on the items that can be packaged, but examples include food products such as fruits, eggs, and vegetables; home appliances and electronic components.

[0076] <Other Embodiments> The laminate of the present invention is not limited to the laminate 10 shown in Figures 1 to 3. For example, the laminate 10 shown in Figures 1 to 3 comprises a first layer 11 and a second layer 12, but the laminate may further comprise other layers (hereinafter also referred to as "other layers") in addition to the first and second layers, as long as the effects of the present invention are not impaired. Other layers may be located on other faces of the first layer and be in contact with the first layer, or they may be located on the face of the second layer opposite to the face in contact with the first layer and be in contact with the second layer. Other layers are preferably made of nonwoven fabric. The nonwoven fabric may be dry-laid, melt-spun, or wet-laid. If the laminate further comprises other layers, it is preferable that the through-holes penetrate not only the first and second layers but also the other layers. [Examples]

[0077] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Embodiments of the present invention can be modified in various ways without changing the gist of the invention.

[0078] [Non-woven fabric] <Nonwoven fabric a-1: Airlaid nonwoven fabric using a water-based binder> Nonwoven fabric a-1 was manufactured using an airlaid nonwoven fabric machine as follows. On a moving mesh conveyor, pulp fibers obtained by defibrating commercially available bleached softwood kraft pulp (NBKP) using a dry defibration device are dropped and deposited along with an airflow, resulting in a basis weight of 76 g / m². 2 It formed a fiber web. On the fiber web, an aqueous binder A (ethylene vinyl acetate copolymer (EVA)) and polyvinyl alcohol (PVA) are mixed, with a solid content of 3 g / m². 2The material was sprayed in this manner. Next, the fiber web was passed through a hot air dryer (ambient temperature 170°C) to bond the fibers together. Then, the fiber web was inverted, and the same amount of water-based binder A was sprayed onto the opposite side of the surface where the first layer of binder A had been applied, and then passed through the hot air dryer (ambient temperature 170°C) again, resulting in a basis weight of 80 g / m². 2 We obtained an airlaid nonwoven fabric. The apparent specific gravity of nonwoven fabric a-1 is 0.10 g / cm³. 3 The thickness is 1.0 mm and the basis weight is 80 g / m². 2 That was the case.

[0079] <Nonwoven fabric a-2: Spunlace nonwoven fabric> As nonwoven fabric a-2, commercially available spunlace nonwoven fabric (manufactured by Shinwa Co., Ltd., product name "7850") was used. The apparent specific gravity of nonwoven fabric a-2 is 0.17 g / cm³. 3 The thickness is 0.3 mm and the basis weight is 50 g / m². 2 That was the case.

[0080] <Nonwoven fabric a-3: Spunbond nonwoven fabric> As nonwoven fabric a-3, a commercially available spunbond nonwoven fabric (manufactured by Toyobo Co., Ltd., product name "Ecure") was used. The apparent specific gravity of nonwoven fabric a-3 is 0.17 g / cm³. 3 The thickness is 0.3 mm and the basis weight is 50 g / m². 2 That was the case.

[0081] <Nonwoven fabric b-1: Airlaid nonwoven fabric with a higher specific gravity than nonwoven fabric a-1> Nonwoven fabric b-1 was manufactured using an airlaid nonwoven fabric machine as follows. On a moving mesh conveyor, pulp fibers obtained by defibrating commercially available bleached softwood kraft pulp (NBKP) using a dry defibration device are dropped and deposited along with an airflow, resulting in a basis weight of 56 g / m². 2 It formed a fiber web. On the fiber web, an aqueous binder C (carboxymethylcellulose sodium (CMC)) is applied, with a solid content of 4 g / m².2 The material was sprayed in this manner. Next, the fiber web was passed through a hot air dryer (ambient temperature 170°C) to bond the fibers together. Then, the fiber web was inverted, and the same amount of water-based binder C was sprayed on the opposite side of the surface where the first layer of binder C had been applied, and then passed through the hot air dryer (ambient temperature 170°C) again, resulting in a basis weight of 60 g / m². 2 We obtained an airlaid nonwoven fabric. The apparent specific gravity of nonwoven fabric b-1 is 0.12 g / cm³. 3 The thickness is 0.5 mm and the basis weight is 60 g / m². 2 That was the case.

[0082] <Nonwoven fabric b-2: Water-soluble spunlace nonwoven fabric> For nonwoven fabric b-2, we used commercially available spunlace nonwoven fabric (manufactured by Oji F-Tex Co., Ltd., product name "Texcel Flash"). The apparent specific gravity of nonwoven fabric b-2 is 0.17 g / cm³. 3 The thickness is 0.3 mm and the basis weight is 50 g / m². 2 That was the case.

[0083] <Nonwoven fabric b-3: Kraft paper> For the nonwoven fabric b-3, we used commercially available kraft paper (manufactured by Oji Materia Co., Ltd., product name "OK Unbleached Kraft"). The apparent specific gravity of nonwoven fabric b-3 is 0.75 g / cm³. 3 The thickness is 0.08 mm and the basis weight is 60 g / m². 2 That was the case.

[0084] [Measurement and Evaluation] <Measuring thickness> The cross-section of the laminate was observed under a microscope at three arbitrary locations, and the average thickness of the first layer, the second layer, and the laminate itself was calculated from the images. As a microscope, an electron microscope (Hitachi High-Tech Corporation, product name "FLexSEM1000") was used to observe the cross-section of the laminate at a magnification of 65x.

[0085] <Measurement of basis weight> The basis weight of the laminate was measured in accordance with JIS P 8124:2011. The first layer was peeled off from the laminate, and the basis weight of the first layer was measured in accordance with JIS P 8124:2011. The basis weight of the second layer was obtained by subtracting the basis weight of the first layer from the basis weight of the laminate.

[0086] <Evaluation of lamination processability> The impact absorption performance was evaluated based on the following evaluation criteria. ○: When manufacturing laminates, nonwoven fabrics can be laminated and joined without using adhesives. ×: When manufacturing laminates, adhesive is required to join the nonwoven fabrics.

[0087] <Evaluation of shock absorption> A single chicken egg was wrapped in a laminated material and secured with tape, then dropped from a height of 40 cm onto the floor. The appearance of the egg after the fall was visually observed, and its impact absorption was evaluated based on the following evaluation criteria. ○: No cracks were observed in the chicken egg after it was dropped, and no leakage of egg white was seen. ×: Cracks were observed in the chicken egg after it was dropped, and egg white leakage was visible.

[0088] <Evaluation of recyclability> The laminate can be disintegrated as is and used as raw material for paper. For the evaluation of recyclability, the laminate was cut into 100mm sections, and its water-soluble properties were confirmed according to the "ease of disintegration" criteria described in JIS P 4501:1993 for "toilet paper". Furthermore, after disintegrating the laminate using a disintegrator, papermaking was performed using the disintegrated raw material, and the papermaking properties and the presence of foreign matter in the paper after papermaking were visually inspected. Recyclability was evaluated based on the following evaluation criteria. ○: The paper dissolves in water (ease of breaking down) within 100 seconds, and there are no holes or foreign objects in the handmade paper. ×: The paper has a water-soluble (ease of breaking apart) time of more than 100 seconds, or the handmade paper has holes or contains foreign matter larger than 1 mm square.

[0089] [Example 1] Using the manufacturing apparatus 20 shown in Figure 4, the laminate was fabricated as follows. First, nonwoven fabric a-1 was fed from the first feed roll 211, and separately, nonwoven fabric b-1 was fed from the second feed roll 212. The nonwoven fabric a-1 fed from the first feed roll 211 was laminated onto the nonwoven fabric b-1 fed from the second feed roll 212 to obtain an intermediate product 14. Next, the intermediate material 14 was transported to the slitting means 22 and supplied between the slitting roll 221 and the nip roll 222. The slitting blades provided on the slitting roll 221 formed multiple slit-shaped through-holes penetrating the nonwoven fabric a-1 and nonwoven fabric b-1 in a staggered pattern, such that the longitudinal direction of the through-holes was parallel to the transport direction of the intermediate material 14. At the same time, the nonwoven fabric a-1 and nonwoven fabric b-1 were joined together, with nonwoven fabric a-1 becoming the first layer, i.e., nonwoven fabric A-1, and nonwoven fabric b-1 becoming the second layer, i.e., nonwoven fabric B-1, thereby obtaining a strip-shaped laminate 10. The length L of the through-holes was 10 mm, the distance D between adjacent through-holes in a row of through-holes was 3 mm, and the width W of adjacent rows of through-holes was 3 mm. Next, the strip-shaped laminate 10 was conveyed to the cutting means 23, and the cutting machine 231 cut it in a direction perpendicular to the conveying direction of the strip-shaped laminate 10 to the desired size, obtaining a single-sheet laminate 10 with dimensions of 20 cm in length, 30 cm in width, and 1.3 mm in thickness, in which a first layer made of nonwoven fabric A and a second layer made of nonwoven fabric B were joined together. The thickness and basis weight of the first and second layers of the resulting laminate 10 were measured. Impact absorption and recyclability were also evaluated. The results are shown in Table 1. Furthermore, the first layer constituting the laminate manufactured using nonwoven fabric a-1 is also referred to as "nonwoven fabric A-1," and the second layer constituting the laminate manufactured using nonwoven fabric b-1 is also referred to as "nonwoven fabric B-1." Similarly, in the examples and comparative examples shown below, the first layer constituting the laminate manufactured using nonwoven fabric a-2 is also referred to as "nonwoven fabric A-2," the first layer constituting the laminate manufactured using nonwoven fabric a-3 is also referred to as "nonwoven fabric A-3," the first layer constituting the laminate manufactured using nonwoven fabric a-4 is also referred to as "nonwoven fabric A-4," the second layer constituting the laminate manufactured using nonwoven fabric b-2 is also referred to as "nonwoven fabric B-2," and the second layer constituting the laminate manufactured using nonwoven fabric b-3 is also referred to as "nonwoven fabric B-3."

[0090] [Example 2] A laminate was manufactured in the same manner as in Example 1, except that nonwoven fabric b-2 was used instead of nonwoven fabric b-1, and various measurements and evaluations were performed. These results are shown in Table 1.

[0091] [Example 3] A laminate was manufactured in the same manner as in Example 1, except that nonwoven fabric b-3 was used instead of nonwoven fabric b-1, and various measurements and evaluations were performed. These results are shown in Table 1.

[0092] [Comparative Example 1] A laminate was manufactured in the same manner as in Example 1, except that nonwoven fabric a-2 was used instead of nonwoven fabric a-1, and various measurements and evaluations were performed. These results are shown in Table 2.

[0093] [Comparative Example 2] We attempted to manufacture a laminate with a thickness of 0.38 mm in the same manner as in Example 1, by using nonwoven fabric a-2 instead of nonwoven fabric a-1 and nonwoven fabric b-3 instead of nonwoven fabric b-1, and feeding nonwoven fabric a-2 from the first feed roll 211 and b-3 from the second feed roll 212. However, the combination of spunlace nonwoven fabric and kraft paper did not bond. Therefore, a laminate with a thickness of 0.38 mm was manufactured in the same manner as in Example 1, except that two nonwoven fabrics a-2 and b-3 were bonded together with an adhesive (Cemedine Co., Ltd., product name "Cemedine C") to form an intermediate, and its impact absorption and recyclability were evaluated. The results are shown in Table 2.

[0094] [Comparative Example 3] We attempted to manufacture a laminate with a thickness of 1.2 mm in the same manner as in Example 1, by using nonwoven fabric a-3 instead of nonwoven fabric a-1 and nonwoven fabric b-3 instead of nonwoven fabric b-1, and feeding nonwoven fabric a-3 from the first feed roll 211 and b-3 from the second feed roll 212. However, the combination of spunbond nonwoven fabric and kraft paper did not bond. Therefore, a laminate with a thickness of 1.2 mm was manufactured in the same manner as in Example 1, except that two nonwoven fabrics a-3 and b-3 were bonded together with an adhesive (Cemedine Co., Ltd., product name "Cemedine C") to form an intermediate, and its impact absorption and recyclability were evaluated. The results are shown in Table 2.

[0095] [Table 1]

[0096] [Table 2]

[0097] As is clear from the results in Table 1, the laminates obtained in Examples 1 to 3 exhibited excellent shock absorption and recyclability. In particular, the laminate obtained in Example 1 had superior shock absorption compared to the laminates obtained in Examples 2 and 3. On the other hand, as is clear from the results in Table 2, the laminate obtained by combining nonwoven fabric a-2 and nonwoven fabric b-1 was unsuitable for recycling (Comparative Example 1). In combinations of nonwoven fabric a-2 or nonwoven fabric a-3 and nonwoven fabric b-3, bonding did not occur simply by forming through holes (Comparative Examples 2 and 3). While these nonwoven fabrics could be bonded together using adhesive, the laminates obtained in Comparative Examples 2 and 3 were unsuitable for recycling. Furthermore, they also exhibited poor shock absorption. [Explanation of symbols]

[0098] 10 Laminate 11 The first layer 11a One side 12. The Second Layer 13 Through hole 14 Intermediates 20 Manufacturing equipment 21 Lamination method 211 First feed roll 212 Second feed roll 22 Slitting process 221 Slit Roll 222 Nip Roll 23 Cutting means 231 Cutting machine

Claims

1. A laminate comprising a first layer and a second layer located on one surface of the first layer and in contact with the first layer, The first layer is an airlaid nonwoven fabric. The second layer is a nonwoven fabric, The first layer and the second layer are joined together. A laminate in which a plurality of slit-shaped through holes are arranged in a staggered pattern, penetrating the first layer and the second layer.

2. The laminate according to claim 1, wherein the apparent specific gravity of the second layer is greater than the apparent specific gravity of the first layer.

3. The laminate according to claim 2, wherein the second layer is one or more selected from airlaid nonwoven fabric, spunlace nonwoven fabric, and wet-laid nonwoven fabric.

4. The process includes a joining step that joins the first layer and the second layer. The first layer is an airlaid nonwoven fabric. The second layer is a nonwoven fabric, A method for manufacturing a laminate, wherein the joining step is a step of providing a plurality of slit-shaped through holes that penetrate the first layer and the second layer in a staggered pattern.

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