JP6748420B2 - Laminated body and manufacturing method thereof - Google Patents

Description

The present invention relates to a laminate of different materials having different affinity for water.

BACKGROUND ART Conventionally, in various applications such as packaging materials, a laminated body in which a plurality of base materials made of various materials are laminated and integrated is used. For example, as a laminate for a packaging material, a laminate of hydrophobic resins such as a laminate of a polyamide resin film and a polyethylene resin film is often used. A chemical adhesive such as a hot-melt adhesive is often used for joining the layers in such a laminate. However, the use of an adhesive has problems in terms of environmental measures and energy saving measures. In addition, since the part coated with the adhesive is relatively hard and has low air permeability, it is not necessary to use the adhesive in applications requiring high flexibility and air permeability, such as hygiene products. There is a demand for a technique capable of producing a laminate having the required bonding strength.

In order to meet such demands, it has been proposed to join layers by using plasma treatment in the production of a laminate of materials made of thermoplastic resin.
For example, in Patent Document 1, as a method of joining an aramid paper obtained by wet-making aramid fibers and a polyethylene terephthalate resin film without an adhesive, a low-temperature plasma treatment is applied to the surface of the aramid paper to form a A method for performing the modification is described.
Further, in Patent Document 2, a second base material which is a thermoplastic resin film of a type different from that of the raw material sheet for a first base material and has heat sealability on both surfaces of a first base material made of a thermoplastic resin film. In a method for producing a packaging material laminate obtained by joining raw material sheets for use with each other, it is described that atmospheric pressure plasma treatment is used for joining the raw material sheets for both substrates.

JP, 2009-138312, A JP, 2011-143586, A

In hygiene products such as disposable diapers, for example, a constituent member made of a hydrophobic resin film such as polyethylene (for example, a leak preventer) and a constituent member mainly composed of hydrophilic cellulose fibers (for example, absorption of a water-absorbent polymer or the like). A laminated body of different materials having different affinities for water is used, such as a laminated body composed of a base material encapsulating a conductive material). From the viewpoint of ensuring flexibility and air permeability, it has been demanded for such a laminated body of different materials to perform bonding between layers without an adhesive, but a technique capable of sufficiently satisfying such a demand is not available. Not yet offered.

An object of the present invention is to provide a laminate that is flexible, has excellent breathability, and has a reduced load on the environment.

The present invention has a laminated structure in which a sheet-shaped first base material and a second base material, which are different from each other, are directly bonded, and the first base material is a film or a non-woven fabric mainly composed of a thermoplastic resin. The second base material is a laminated body which is a fiber assembly mainly composed of cellulosic fibers.

The present invention also relates to an atmospheric pressure plasma treatment step of performing atmospheric pressure plasma treatment in which one side of the first substrate raw sheet is brought into contact with atmospheric pressure plasma generated under atmospheric pressure by a plasma apparatus using a treatment gas. An integral unit that superimposes the original fabric sheet for the second substrate on one side of the original fabric sheet for the first substrate that has been subjected to the atmospheric pressure plasma treatment, and heats and presses the laminated body to integrate the two sheets. The manufacturing method of the laminated body which has a conversion process.

According to the present invention, there is provided a laminate which is flexible, has excellent breathability, and has a reduced load on the environment.

FIG. 1 is a schematic diagram of an embodiment of an atmospheric pressure plasma treatment step in the method for producing a laminated body of the present invention.

The laminated body of the present invention has a laminated structure in which a sheet-shaped first base material and a second base material that are different from each other are directly bonded. The term “mutually different from each other” as used herein means that, as is clear from the comparison of the main components of the first base material and the second base material (that is, the thermoplastic resin and the cellulosic fiber), the first base material. It means that the second base material has completely different basic characteristics, and does not include joining of thermoplastic resins of the same kind or different kinds as described in Patent Documents 1 and 2. Specific examples of the “basic characteristics” include “affinity for water”. That is, the first base material mainly composed of a thermoplastic resin is basically hydrophobic, whereas the second base material mainly composed of cellulosic fibers is basically hydrophilic and both base materials are Have different affinities for water and are therefore different from one another.

The first base material according to the present invention is a film or a non-woven fabric mainly composed of a thermoplastic resin. The term "mainly composed of a thermoplastic resin" as used herein means that the content of the thermoplastic resin in the first base material is 50% by mass or more. The content of the thermoplastic resin in the first base material is preferably 65% by mass or more, more preferably 70% by mass or more, and may be 100% by mass. As the thermoplastic resin, those used for various purposes such as hygiene products and packaging materials can be used without particular limitation. For example, polyolefins such as polyethylene (abbreviated as PE) and polypropylene (abbreviated as PP) can be used. Resins: Polyester terephthalate (PET for short), polybutylene terephthalate (PBT for short), polyester resin such as polylactic acid resin; polyamide resin such as nylon 6; polyacrylic resin such as polyethyl acrylate; poly Examples thereof include vinyl chloride resins; polyurethane resins; cellulose derivative resins, and the like, and these can be used alone or in combination of two or more. Among these thermoplastic resins, polyolefin-based resins and polyester-based resins are preferable from the viewpoint that the glass transition temperature is generally 100° C. or lower.

The film containing the thermoplastic resin as a main component (that is, the first substrate) is typically a film of a resin or a resin composition and has a flat shape with no through holes. Without being limited to this, a thermoplastic resin film used in various applications can be used without particular limitation. Specific examples include a low density PE film and a biaxially stretched PET film. The thickness of the film is not particularly limited and may be appropriately set depending on the application of the laminate. For example, when the application of the laminate is a leak preventer for disposable diapers, the thickness of the film as the first base material is preferably 0.5 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, more preferably Is 30 μm or less.

The non-woven fabric mainly made of a thermoplastic resin (that is, the first substrate) is typically a non-woven fabric made of a thermoplastic resin fiber. The type of non-woven fabric is not particularly limited, and for example, spun-bonded non-woven fabrics, spun-laced non-woven fabrics, melt-blown non-woven fabrics, air-bonded non-woven fabrics, thermal-bonded non-woven fabrics, needle-punched non-woven fabrics, and the like can be used, or two or more non-woven fabrics can be used. It is also possible to use a laminated body of, for example, a spunbond-meltblown-spunbond (SMS for short) nonwoven fabric. However, for the air-through nonwoven fabric, the thermal bond nonwoven fabric, and the needle punch nonwoven fabric, it is preferable to use those that have been washed with water or hot water and the process oil has been removed from the fiber surface. The basis weight of the nonwoven fabric as the first base material is not particularly limited and may be appropriately set depending on the application of the laminate. For example, when the use of the laminate is a leak preventer for disposable diapers, the basis weight of the nonwoven fabric as the first substrate is preferably 3 g/m ² or more, more preferably 5 g/m ² or more, and preferably It is 70 g/m ² or less, more preferably 25 g/m ² or less.

The constituent fibers of the non-woven fabric mainly composed of a thermoplastic resin (that is, the first substrate) may be a single fiber composed of one kind of thermoplastic resin, or a composite fiber containing two or more kinds of thermoplastic resins having different melting points. good. As the composite fiber, a core-sheath type in which a resin having a relatively low melting point (that is, a low melting point resin) is a sheath portion and a resin having a relatively high melting point (that is, a high melting point resin) is a core portion; a low melting point resin and a high melting point resin Examples thereof include a side-by-side type in which a resin and a resin are arranged in parallel in a predetermined direction, and any of them can be used in the present invention. Specifically, for example, a core-sheath type composite fiber having PET as a core portion and PE as a sheath portion can be mentioned. The average fiber diameter of the constituent fibers of the nonwoven fabric is not particularly limited, but is usually in the range of 0.1 to 30 μm.

On the other hand, the second base material according to the present invention is a fiber assembly mainly composed of cellulosic fibers. A fiber assembly is a fiber assembly obtained by laminating fiber materials such as cellulosic fibers, and in the fiber assembly, the fiber shape (or string shape) originally possessed by each fiber material is substantially maintained. And has many inter-fiber voids. The term “mainly composed of cellulosic fibers” as used herein means that the content of cellulosic fibers in the second base material is 50% by mass or more. The content of the cellulosic fibers in the second base material is preferably 65% by mass or more, more preferably 70% by mass or more, and may be 100% by mass.

As the cellulosic fibers, those used for various applications including hygiene products can be used without particular limitation, and examples thereof include natural cellulose fibers, mercerized cellulose fibers, dissolved cellulose fibers and cellulose fiber derivatives. , These 1 type can be used individually or in combination of 2 or more types. Examples of the natural cellulose fiber include wood pulp such as softwood pulp and hardwood pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp, bagasse pulp and hemp pulp; waste paper pulp and the like. As is well known, the mercerized cellulose fiber is a cellulose fiber that has been alkali-modified (so-called mercerized) by a concentrated alkali treatment. Examples of the dissolved cellulose fiber include Lyocell (registered trademark), TENCEL (registered trademark), Bemberg (registered trademark), viscose rayon, and Benliese (registered trademark). Examples of the cellulose fiber derivative include carboxymethyl cellulose, carboxyethyl cellulose, TEMPO-catalyzed oxidized cellulose, methyl cellulose, ethyl cellulose and the like.

The second base material according to the present invention is typically a paper or a nonwoven fabric manufactured by a known wet papermaking method. The basis weight of the paper or the non-woven fabric as the second base material is not particularly limited and may be appropriately set depending on the application of the laminate. For example, when the application of the laminate is a leak preventer for disposable diapers, the basis weight of the paper or nonwoven fabric as the second base material is preferably 10 g/m ² or more, more preferably 12 g/m ² or more, and It is preferably 50 g/m ² or less, more preferably 30 g/m ² or less.

One of the main characteristics of the laminate of the present invention is that the first base material and the second base material that are different from each other are directly bonded. The “direct bonding” in the present invention means a state in which the first base material and the second base material are directly overlapped and bonded to each other without interposing an adhesive component. The term "adhesive component" as used herein refers to an adhesive separate from both base materials, and a substance contained in both base materials and capable of becoming an adhesive component by heating (typically the first group). Material thermoplastic resin) is included. Therefore, the "direct bonding" in the present invention includes i) a mode in which the first base material and the second base material are bonded to each other via an adhesive, and ii) either one or both of the base materials. The form (so-called heat fusion) in which both base materials are bonded to each other due to the fact that (the first base material mainly composed of a thermoplastic resin) is heat-fusible by heating is not included.

Such "direct bonding" of the first base material and the second base material without using an adhesive component is performed by performing atmospheric pressure plasma as a pretreatment on the raw material sheet for the first base material mainly composed of a thermoplastic resin. After the treatment, it can be realized by superposing the second base material sheet on the atmospheric pressure plasma treated surface and heating and pressurizing it. That is, the laminate of the present invention is 1) subjected to atmospheric pressure plasma treatment in which one side of the first base material sheet is brought into contact with atmospheric pressure plasma generated under atmospheric pressure by a plasma device using a processing gas. Atmospheric pressure plasma treatment step, and 2) stacking the second raw material sheet on one surface of the first raw material sheet that has been subjected to the atmospheric plasma treatment, and heating and pressing the stacked body. It can be manufactured through an integration process of integrating both sheets.

The "raw material sheet for the first base material" referred to here is a main raw material of the first base material forming the laminate of the present invention, and the raw material sheet is subjected to the atmospheric pressure plasma treatment before the first raw material. A substrate is obtained. Further, the “raw sheet for second base material” is a main raw material of the second base material forming the laminate of the present invention. The method for producing a laminate of the present invention includes an aspect in which the second raw material sheet is subjected to atmospheric pressure plasma treatment and an aspect in which no modification treatment such as atmospheric pressure plasma treatment is applied. However, in the former aspect, the raw sheet for the second base material and the second base material are substantially the same, and in the latter aspect, the raw sheet for the second base material is subjected to the atmospheric pressure plasma treatment before. As a result, the second base material is obtained.

Incidentally, in a laminated body of a first base material which is a film or a non-woven fabric mainly composed of a thermoplastic resin and a second base material which is a fiber assembly mainly composed of a cellulosic fiber, both base materials are "directly bonded". Whether or not it can be determined by measuring the contact angle with respect to water or the wetting tension on the joint surface of the first base material with the second base material. Further, a certain "film or nonwoven fabric mainly composed of a thermoplastic resin" (that is, a raw material sheet for a first substrate) is "a fiber assembly mainly composed of a cellulosic fiber" (that is, a raw material sheet for a second substrate). Or, whether or not it can be "directly joined" to the second base material, the contact angle to water or the contact angle with respect to the surface to be joined to the second base material sheet in the first base material sheet It can be judged by measuring the wetting tension. Further, as described above, the “direct bonding” can be realized by the atmospheric pressure plasma treatment of the raw material sheet for the first base material, and thus the contact angle of water with respect to the first base material or the raw material sheet for the first base material. Alternatively, by measuring the wetting tension, it is possible to determine whether or not it has been subjected to atmospheric pressure plasma treatment.

That is, in the case where the first base material is a film, when the contact angle of water on the joint surface of the first base material, ie, the film, with the second base material is 60° or less, the first base material or film Can be judged to be directly overlaid on and bonded to the second base material without the interposition of an adhesive component, or it can be judged to have been subjected to atmospheric pressure plasma treatment. There is no particular lower limit to the contact angle of the first base material, that is, the surface of the film to be joined to the second base material with water, but the contact angle is preferably closer to 0°. The contact angle with water is measured according to JIS R 3257:1999.

When the first base material is a non-woven fabric and the wetting tension of the joint surface of the first base material, that is, the non-woven fabric with the second base material is 55 mN/m or more, the first base material or the non-woven fabric is It can be judged that it can be directly overlaid and bonded to the second base material without the interposition of an adhesive component, or it has been subjected to atmospheric pressure plasma treatment and is mainly composed of a hydrophobic thermoplastic fiber and has a surface active property. It can be judged that the wetting tension was improved by the atmospheric pressure plasma treatment even though the agent was not applied. There is no particular upper limit for the wetting tension of the first base material, that is, the surface of the nonwoven fabric bonded to the second base material, with respect to water, and may exceed 73 mN/m (however, the surface tension of mercury is 427 mN/m). It is not necessary to have a wetting tension of up to m). The wetting tension of the nonwoven fabric is measured by the following method.

<Measuring method of wetting tension of non-woven fabric>
A nonwoven fabric to be measured is stretched horizontally in the air in an environment region of an ambient temperature of 20° C., 15 μL of a wetting tension test liquid is dropped on the upper face of the nonwoven fabric, and 20 seconds after the dropping of the test liquid, 20% after the test liquid is dropped on the upper face. Visually observe the state of the test solution. In the observation, when the test solution permeates in the thickness direction of the nonwoven fabric or diffuses in the plane direction, the test solution having a larger surface tension is used and the same operation is performed. Then, when the test liquid cannot pass through the non-woven fabric and the droplet remains on the upper face of the non-woven fabric, or when almost no wetting is observed on the upper face without spreading in the surface direction, the dropping operation immediately before such a case The surface tension of the test liquid used for the above, that is, the surface tension of the test liquid having the maximum surface tension among the test liquids capable of permeating or diffusing the non-woven fabric is the wetting tension of the non-woven fabric at the ambient temperature of 20°C. As the wetting tension test liquid, a mixed liquid of ethylene glycol monoethyl ether, formamide, methanol and water prepared according to JIS K 6768:1999 is used, and the surface tension is adjusted by appropriately changing the mixing ratio of each component. Such a wetting tension test liquid is commercially available, for example, from Wako Pure Chemical Industries, Ltd. under the trade name of a wetting tension test mixture.

FIG. 1 shows an outline of one embodiment of the plasma treatment process. The plasma device 10 used in the present embodiment is a so-called remote type plasma device in which atmospheric pressure plasma G generated between the electrodes 12 and 12 is blown toward a processing object arranged outside the pair of electrodes 12 and 12. Is. The plasma device 10 includes a processing head 11 arranged to face a processing object, and a pair of electrodes 12, 12 are arranged inside the processing head 11 so as to face each other. A solid dielectric layer is formed. One of the electrodes 12, 12 is connected to a power supply 13 and the other is electrically grounded, and a voltage is supplied from the power supply 13 so that the space between the electrodes 12, 12 is discharged at or near atmospheric pressure. It becomes space 14. The processing gas introduction port 15 side of the discharge space 14 communicates with the processing gas G′ supply source 16. In the plasma apparatus 10 having such a configuration, the processing gas G′ is introduced from the supply source 16 into the discharge space 14 to generate the atmospheric pressure plasma G (that is, the plasmaized processing gas G′), and the atmospheric pressure is generated. The plasma G is blown out from the gas blowing port 17 at the lower end of the processing head 11, and the lower side of the gas blowing port 17 is blown onto one surface (that is, the upper surface) of the first base material sheet 20 (that is, the processing object) being conveyed. Has been done. The first base material sheet 20 in the illustrated mode has a continuous strip shape, and is conveyed below the processing head 11 by the conveyor 19 with its longitudinal direction aligned with the conveyance direction MD. As the processing gas G', one or more selected from the group consisting of nitrogen and oxygen or the atmosphere can be used.

The raw material sheet 20 for a first base material that has been subjected to the atmospheric pressure plasma treatment in the mode as shown in FIG. The upper surface of the raw material sheet 20 for use, that is, the surface opposite to the side of the conveyor 19 is reformed, and is inherently chemically bonded to the second base material (or the second base material sheet). It changes from the impossible state to the joinable state. That is, the raw sheet 20 for the first base material becomes the first base material by the atmospheric pressure plasma treatment. Although the mechanism of surface modification of the first base material sheet 20 by such atmospheric pressure plasma treatment is not clear, for example, when the first base material sheet 20 is a polyethylene film, the surface thereof has hydrogen atoms. Are inherently hydrophobic (that is, the contact angle with water is about 90°), but some of the hydrogen atoms on the surface are replaced with polar groups such as ketones and hydroxyl groups by atmospheric pressure plasma treatment. It is speculated that this is due to the surface being hydrophilized (that is, the contact angle with water becomes about 50°). Then, on the hydrophilized first substrate raw sheet 20, that is, on the atmospheric pressure plasma-treated surface of the first substrate, the second substrate raw sheet, which is a fiber assembly mainly composed of cellulosic fibers, By heating and pressurizing the second base material on top of each other, polar groups such as ketones and hydroxyl groups existing on the atmospheric pressure plasma treated surface of the first base material and polarities such as hydroxyl groups originally present on the surface of the second base material. It is presumed that the group is chemically bonded by a dehydration condensation reaction or the like, or physically bonded by a hydrogen bond, and as a result, “direct bonding” between the first base material and the second base material is performed. ..

The atmospheric pressure plasma treatment includes a remote type plasma treatment as shown in FIG. 1 and a so-called direct type in which an object to be treated is placed in a discharge space (that is, between a pair of electrodes) to perform the treatment. Either method can be used. In the remote type plasma processing, since the plasma generation region (discharge space) and the processing target object processing region are separated from each other, electrons existing in the discharge space do not collide with the processing target object unlike the direct plasma processing. Another advantage is that the object to be processed is not subject to electric field damage such as discharge damage and heat damage. Further, as shown in FIG. 1, the remote plasma processing can continuously perform processing on an object to be processed, and therefore has an advantage of high manufacturing efficiency as compared with a batch processing method. Have From the above points, the remote plasma treatment is preferable as the atmospheric pressure plasma treatment according to the present invention.

In the atmospheric pressure plasma processing step of the present embodiment, the suction means (not shown) included in the conveyor 19 causes the other side of the first base material sheet 20 (that is, the object to be processed) being conveyed, that is, the atmospheric pressure. The first base material sheet 20 is suctioned from the side opposite to the surface on which the plasma G is sprayed. The main purpose of such suction is to fix the first base material sheet 20 that is the object to be processed, and the first base material sheet 20 is fixed to the conveyor 19 by such suction, for example, Flipping and meandering during transport of the first base material sheet 20 are prevented, and thereby the reforming efficiency of the first base material sheet 20 by the atmospheric pressure plasma G is improved, and the second base material The realization of direct bonding can be even more reliable. The suction of the first base material sheet 20 is preferably performed at least before and after the time point at which the plasma G is sprayed on the first base material sheet 20, that is, from the outlet 17 of the atmospheric pressure plasma G. It is preferable to carry out over a position separated by a predetermined distance in the transport direction MD and the opposite direction. As a means for sucking the first base material sheet 20, a known suction means capable of sucking various sheets can be used.

Further, in this embodiment, as shown in FIG. 1, before the atmospheric pressure plasma is brought into contact with the first base material sheet 20 (that is, the object to be treated), the first base material is heated by using the heating means 18. The raw sheet 20 is heated. The heating means 18 in the present embodiment is a device for blowing hot air (so-called heating air), and is large in the first raw material sheet 20 on the upstream side of the outlet 17 of the atmospheric pressure plasma G in the transport direction MD. It is arranged so as to face the surface on which the atmospheric pressure plasma G is blown (that is, the atmospheric pressure plasma treatment surface), and hot air is directly blown to the atmospheric pressure plasma treatment surface to heat it. By such heat treatment of the raw material sheet 20 for the first base material, the reforming efficiency of the raw material sheet 20 for the first base material by the subsequent atmospheric pressure plasma spraying is improved, and the raw material sheet for the second base material (or The realization of the direct bonding with the second base material) can be further ensured. In addition, as shown in FIG. 1, the heating method of the first base material sheet 20 is performed by using a hot air in a form in which an atmospheric pressure plasma processing means and a heating means (that is, a hot air blowing device) are integrated. However, for example, the atmospheric pressure plasma treatment means and a dryer separate from the atmospheric pressure plasma treatment means are used, and the first base material sheet 20 is conveyed to the dryer and dried before the contact with the atmospheric pressure plasma. It is also possible to blow hot air in the machine.

The heating temperature of the first raw material sheet 20 for a first substrate before contacting with the atmospheric pressure plasma is, for example, in the case of a transport speed of 25 m/min, from the viewpoint of more reliably producing the modification effect by the heat treatment, The glass transition temperature of the thermoplastic resin contained in the first base material sheet 20 is preferably 70° C. or higher and the melting point of the thermoplastic resin is lower than 50° C. The “heating temperature of the raw material sheet for the first base material” here does not mean the temperature of the heated raw material sheet for the first base material 20 itself (so-called product temperature), but the heating means itself or the heating. Means the heating set temperature by the means, for example, when the heating means is hot air as shown in FIG. 1, the temperature of the hot air at the surface (that is, the atmospheric pressure plasma treatment planned surface) position of the first base material sheet 20 is means. In the case where the raw material sheet 20 for the first base material contains a plurality of types of thermoplastic resins having different glass transition temperatures, the “thermoplastic resin contained in the raw material sheet for the first base material” is When the core-sheath fiber is blended, it is used as the resin of the sheath component, and when plural kinds of fibers are blended, it is the most mass% of the blending ratio in the first base material sheet 20. Means a large resin. The melting point can be considered similarly to the glass transition temperature. The reason for setting the heating temperature of the first base material sheet 20 to the glass transition temperature of the thermoplastic resin contained therein or higher is mainly the adhesiveness with the second base material sheet (or the second base material). The reason for setting the heating temperature to the melting point of the thermoplastic resin plus less than 50° C. is to maintain the shape of the first base material sheet 20.

According to the knowledge of the present inventors, the larger the number of times the atmospheric pressure plasma is brought into contact with the first raw material sheet 20 (that is, the number of plasma treatments), the more the surface modifying effect of the first raw material sheet 20 is improved. As a result, the direct bonding with the raw material sheet for the second base material (or the second base material) can be stronger. Therefore, for example, as shown in FIG. 1, after the atmospheric pressure plasma G is sprayed on one surface of the first base material sheet 20, the same method is performed again on the first surface of the first base material sheet 20. By spraying the atmospheric pressure plasma G, the one surface of the first base material original sheet 20 may be subjected to the atmospheric pressure plasma treatment twice in total. The number of plasma treatments on one surface of the first base material sheet 20 may be three or more. That is, in the method for manufacturing a laminate of the present invention, atmospheric pressure plasma is contacted with one surface of the first base material sheet (that is, the surface to be joined to the second base material sheet) at least once. Embodiments are included. It should be noted that the atmospheric pressure plasma may be brought into contact with each of both surfaces of the first base material sheet 20 once or more.

On the other hand, the raw material sheet for a second base material does not need to be subjected to atmospheric pressure plasma treatment because it has a polar group such as a hydroxyl group on its surface and does not require surface modification. The raw sheet for two base materials can be used as it is as the second base material. However, direct bonding between the first base material and the second base material is made stronger by subjecting the second base material sheet to the atmospheric pressure plasma treatment similarly to the first base material sheet. There is a possibility that favorable results can be obtained, such as that In the method for manufacturing a laminate of the present invention, the raw material sheet for the second base material is not subjected to atmospheric pressure plasma treatment, or the raw material sheet for the second base material has a large surface facing the first base material. A mode in which the atmospheric pressure plasma is contacted once or more is included, and the atmospheric pressure plasma may be contacted with each side of the second base material sheet once or more.

In the method for manufacturing a laminated body of the present invention, the raw material sheet 20 for the first base material, that is, the raw material sheet 20 for the second base material (or the second raw material) that has been subjected to the above-described atmospheric pressure plasma treatment, on one side of the first base material. The base materials are superposed to obtain a superposed body, and the superposed body is heated and pressed to integrate both sheets, that is, both base materials (that is, an integration step). If only the atmospheric pressure plasma treatment step is performed and the integration step is not performed, direct joining of both base materials is difficult and both steps are essential. The integration step can be performed using a known heating/pressurizing device, and can be performed, for example, by passing the superposed body between a pair of heating/pressurizing rolls. Further, it can be carried out by using a manual heat press device as another means, the heating and pressurizing conditions in this case can be appropriately set depending on the application of the laminate, etc. The heating temperature of the body is preferably 80° C. or higher, more preferably 90° C. or higher, and preferably 120° C. or lower, more preferably 110° C. or lower. The pressure applied to the superposed body is preferably 0.1 MPa or more, more preferably 5 MPa or more, and preferably 30 MPa or less, more preferably 25 MPa or less. If the heating temperature and pressure of the superposed body are too low, direct bonding between the first base material and the second base material may be difficult, and if the heating temperature and pressure of the superposed body are too high, it is desirable. There is a risk of melting the first base material or significantly changing the texture. The manual heat press apparatus includes a pair of flat plate-shaped heating and pressing members facing each other, and heats an object to be processed (that is, the superposed body) placed between the members while compressing the members. It is a device.

As described above, the laminated body of the present invention manufactured through the atmospheric pressure plasma treatment and the heating/pressurizing treatment has, for example, a hot melt because the first base material and the second base material are directly bonded without an adhesive. Compared to conventional laminates manufactured using chemical adhesives such as mold adhesives, they have the advantage of being flexible and excellent in breathability and reducing the load on the environment, but practically It has sufficient bonding strength. Since the bonding strength between the first base material and the second base material that are directly bonded in the laminate of the present invention varies depending on the type of the base material and the like, the settable range is wide, but usually 0.5 to 150 cN. The range is /10 mm. For example, the first base material (or the raw material sheet for the first base material) is a film mainly composed of a thermoplastic resin, and the second base material (or the raw material sheet for the second base material) is mainly composed of a cellulosic fiber. In the case of paper, the bonding strength of both base materials is preferably 1 cN/10 mm or more, more preferably 2 cN/10 mm or more. Further, the first base material (or the raw material sheet for the first base material) is a non-woven fabric mainly composed of a thermoplastic resin, and the second base material (or the raw material sheet for the second base material) is mainly composed of a cellulosic fiber. In the case of paper, the bonding strength of both base materials is preferably 1 cN/10 mm or more, more preferably 2 cN/10 mm or more. The bonding strength can be adjusted by appropriately adjusting the conditions of the atmospheric pressure plasma treatment and/or the heating/pressurizing treatment. The bonding strength is measured by the following method.

<Measuring method of bonding strength of laminated body>
The 180° peeling (T-type peeling) specified in JIS Z 0237:2009 is performed according to the measuring method of the adhesive force. A strip having a width of 100 mm and a length of 20 mm or more is sampled from the laminate to be measured to obtain a test piece. Under the environment of 20° C. and 65% RH, the tensile tester (manufactured by Shimadzu Corporation, Autograph (registered trademark) AG-IS 100N) is sandwiched between both longitudinal ends of the test piece, and the peeling speed is 300 mm in that state. The peel strength is measured by peeling in a 180° direction at a peeling speed of min/min (peel length 100 mm). The measurement result is divided by the width (unit: mm) of the test piece to obtain the bonding strength per 10 mm width (unit: cN/10 mm).

The laminated structure of the laminate of the present invention may be a two-layer structure having at least one layer of the first base material and one layer of the second base material, and such a two-layer structure may further include one or more layers of the first base material and It may have a laminated structure of three or more layers in which the second base material is laminated. For example, a three-layer structure in which one layer of the second base material is directly bonded to both surfaces of the one layer of the first base material may be used, and at the time of manufacturing such a three-layer structure, an intermediate layer of the three-layer structure is formed. It is preferable to perform atmospheric pressure plasma treatment on each of both sides of one substrate raw sheet.

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the examples.

[Example 1]
A commercially available low-density PE film (trade name “Novatech (registered trademark)”, manufactured by Mitsubishi Chemical Corporation, thickness 22 μm) was used as the raw sheet for the first base material, and the basis weight was used as the raw sheet for the second base material. Paper consisting of 20 g/m ² of natural cellulose fibers was used. The paper used as the raw sheet for the second base material was 100% kraft pulp bleached from softwood as a raw material, and after being disintegrated according to JIS P 8220:1998, a Canadian standard freeness of 560 mL was obtained according to JIS P 8121:2012. It was beaten until it became, and wet papermaking was carried out in accordance with JIS P 8223:2005.
Atmospheric pressure plasma treatment was performed on one side of the first substrate raw sheet using the same apparatus as the remote plasma apparatus 10 shown in FIG. 1 (that is, atmospheric pressure plasma treatment step). Details of various conditions in the atmospheric pressure plasma treatment process are as follows.
Then, the raw material sheet for the first base material that has been subjected to the atmospheric pressure plasma treatment, that is, the raw material sheet for the second base material (or the second base material) is superposed on one surface of the first base material, and the superposed body is formed. Both sheets (that is, the base material) were integrated by heating and pressurizing to obtain a target laminate (that is, an integration step). Details of various conditions in the integration process are as follows.

(Various conditions in plasma treatment process)
-Remote plasma device: Tough Plasma (registered trademark) FPE20 (manufactured by Fuji Machine Manufacturing Co., Ltd.)
・Distance between the plasma outlet and the original sheet for the first substrate (that is, the object to be treated): 5 mm
-Conveying speed of the first base material sheet (that is, the object to be processed) during the atmospheric pressure plasma processing: 25 m/min
・Processing control method: Controlled by a two-axis robot (manufactured by IAI Co., Ltd.) (here, processing over A4 size)
-Nitrogen (purity 99.9% or more and oxygen content 0.1% or less) was used as the processing gas, and the flow rate of the processing gas was 30 L/min.
-The heated object was heat-treated using the heated air before being sprayed with the atmospheric pressure plasma. The atmosphere was used as the heating air. The flow rate of the heating air was 20 L/min, and the heating temperature (that is, the temperature of the heating air at the surface position of the object to be treated) was 150°C.
During the atmospheric pressure plasma processing, the processing object was sucked from the side opposite to the surface of the processing object to which the atmospheric pressure plasma was sprayed.

(Various conditions in the integration process)
・Device: Mini Test Press-10 manufactured by Toyo Seiki Co., Ltd.
・Heating temperature of superposed body: 100℃
・Pressure applied to the stack: 25 MPa
・Heating time: 10 seconds

[Example 2]
Same as Example 1 except that a commercially available biaxially stretched PET film (trade name “Tetron (registered trademark) G2C”, Teijin Ltd., thickness 25 μm) was used as the first substrate raw sheet. To obtain a laminate.

[Example 3]
As the raw material sheet for the second base material, a commercially available copy paper (trade name "recycle cut size G80 (model number G80A4W), manufactured by Toppan Forms Co., Ltd., recycled paper pulp mixing ratio 70% by mass, forest certification material pulp mixing ratio 30") A laminate was obtained in the same manner as in Example 1 except that the mass% and the basis weight 64 g/m ² ) were used.

[Example 4]
A laminate was obtained in the same manner as in Example 3 except that the same PET film as that used in Example 1 was used as the first base material sheet.

[Example 5]
As a raw sheet for the first base material, a spunbonded nonwoven fabric (trade name "Elves (registered trademark)" (model number S20S0203WDO), unitika ( Co., Ltd., basis weight 20 g/m ² ) was used, and a laminate was obtained in the same manner as in Example 1.

[Example 6]
A laminate was obtained in the same manner as in Example 5 except that the same copy paper as that used in Example 3 was used as the second base material.

[Example 7]
Conducted except that a commercially available paperboard (trade name "color fine paper super thick black", Hokuetsu Kishu Paper Co., Ltd., basis weight 204.5 g/m ² ) was used as the second base material sheet. A laminated body was obtained in the same manner as in Example 5.

[Comparative Examples 1 to 7]
Examples 1 to 1 except that the first base material raw sheet and the second base material raw sheet were integrated together without performing atmospheric pressure plasma treatment on the first base material raw sheet. A laminate was obtained in the same manner as in 7.

〔Evaluation test〕
With respect to the laminates of Examples and Comparative Examples, the bonding strength (that is, T-type peel strength) between the first base material and the second base material was measured by the method described above. The results are shown in Table 1 below.

10 Remote Plasma Apparatus 11 Processing Head 12 Electrode 13 Power Supply 14 Discharge Space 15 Processing Gas Inlet 16 Processing Gas Supply Source 17 Gas Blowout 18 Heating Means 19 Conveyor 20 First Substrate for Base Material (ie Object to be processed)
G'Processing gas G Atmospheric pressure plasma

Claims (10)

It has a laminated structure in which a sheet-shaped first base material and a second base material that are different from each other are directly bonded,
The first base material is a film or non-woven fabric mainly composed of a thermoplastic resin, and the second base material is a fiber assembly mainly composed of cellulosic fibers,
In the direct bonding, a raw sheet which is a main raw material of the first base material is subjected to atmospheric pressure plasma treatment, and then a raw sheet which is a main raw material of the second base material is applied to the atmospheric pressure plasma treated surface. A laminate which is made by stacking and heating and pressing. The laminated body according to claim 1 , wherein the thermoplastic resin of the first base material is at least one selected from the group consisting of polyolefin-based and polyester-based. It is a manufacturing method of the laminated body of Claim 1 or 2 , Comprising:
An atmospheric pressure plasma treatment step of performing atmospheric pressure plasma treatment in which one side of the first base material sheet is brought into contact with atmospheric pressure plasma generated under atmospheric pressure by a plasma device using a treatment gas;
An unification in which the original sheet for the second substrate is superposed on one surface of the original sheet for the first substrate which has been subjected to the atmospheric pressure plasma treatment, and the superposed body is heated and pressed to integrate the two sheets. The manufacturing method of the laminated body which has a process. It has a laminated structure in which a sheet-shaped first base material and a second base material that are different from each other are directly bonded,
The first base material is a film mainly composed of a thermoplastic resin, and the second base material is a fiber assembly mainly composed of a cellulosic fiber,
The cellulosic fiber of the second substrate is one or more selected from the group consisting of natural cellulosic fiber, mercerized cellulosic fiber, dissolved cellulosic fiber and cellulosic fiber derivative,
A method for producing a laminate, wherein a contact angle of water on a joint surface of the first base material with the second base material is 0° to 60°,
An atmospheric pressure plasma treatment step of performing atmospheric pressure plasma treatment in which one side of the first base material sheet is brought into contact with atmospheric pressure plasma generated under atmospheric pressure by a plasma device using a treatment gas;
An unification in which the original sheet for the second substrate is superposed on one surface of the original sheet for the first substrate which has been subjected to the atmospheric pressure plasma treatment, and the superposed body is heated and pressed to integrate the two sheets. The manufacturing method of the laminated body which has a process. It has a laminated structure in which a sheet-shaped first base material and a second base material that are different from each other are directly bonded,
The first base material is a non-woven fabric mainly composed of a thermoplastic resin, and the second base material is a fiber assembly mainly composed of cellulosic fibers,
The cellulosic fiber of the second substrate is one or more selected from the group consisting of natural cellulosic fiber, mercerized cellulosic fiber, dissolved cellulosic fiber and cellulosic fiber derivative,
A method for producing a laminate, wherein a wetting tension of a joint surface of the first base material with the second base material is 55 to 427 mN/m,
An atmospheric pressure plasma treatment step of performing atmospheric pressure plasma treatment in which one side of the first base material sheet is brought into contact with atmospheric pressure plasma generated under atmospheric pressure by a plasma device using a treatment gas;
An unification in which the original sheet for the second substrate is superposed on one surface of the original sheet for the first substrate which has been subjected to the atmospheric pressure plasma treatment, and the superposed body is heated and pressed to integrate the two sheets. The manufacturing method of the laminated body which has a process. The method for producing a laminate according to any one of claims 3 to 5, wherein the processing gas is at least one selected from the group consisting of nitrogen and oxygen or the atmosphere. The laminated sheet according to any one of claims 3 to 6 , wherein the raw material sheet for the first base material is heated before the atmospheric pressure plasma is brought into contact with one surface of the raw material sheet for the first base material. Production method. The heating temperature of the raw material sheet for a first base material is equal to or higher than the glass transition temperature of the thermoplastic resin contained in the raw material sheet for a first base material and lower than the melting point of the thermoplastic resin. A method for manufacturing a laminate. The atmospheric pressure plasma is brought into contact with one surface of the raw material sheet for the first substrate one or more times, and the atmospheric pressure plasma treatment is not applied to the raw material sheet for the second substrate, or the second substrate is used. The method for producing a laminate according to claim 3 , wherein the atmospheric pressure plasma is brought into contact with the surface of the material raw sheet facing the first base material sheet once or more. In the integration step, the superimposed heating temperature of the body 80 ° C. or higher, the superposed pressure applied to the body of the laminate according to any one of claims 3-9 is 0.1MPa or more 30MPa or less Production method.

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