Heat sealing sheet and sterilized packaging body

Abstract

The purpose of the present invention is to provide: an excellent heat-sealing sheet which has sufficient heat adhesiveness and air permeability over the entire heat-sealing surface, has high strength, and is suppressed in the amount of lint generation; a method for producing the heat-sealing sheet; and a sterilized package using the heat-sealing sheet. This heat-sealing sheet has one or more thermoplastic resin fiber nonwoven fabric layers (A) and one or more thermoplastic resin fiber nonwoven fabric layers (B), and is characterized in that: the thermoplastic resin fiber nonwoven fabric layers (B) contain a low-melting-point polyester resin, a polyester fiber, and a polyethylene resin; the mass ratio of the low-melting-point polyester resin, the polyester fiber, and the polyethylene resin (low-melting-point polyester resin: polyester fiber: polyethylene resin) is 13.75: 11.25: 75-41.25: 33.75: 25, the Wangping air permeability measured in accordance with JIS P 8117: 2009 is 700 seconds or less, and the tear strength measured in accordance with JIS P 8116: 2000 is 700 mN or more.

Description

Technical Field

[0001] The invention relates to a heat-sealing sheet and a sterilization packaging body. Background Art

[0002] Instruments used in surgery, treatment, etc. are placed in sterilized packaging bodies for sterilization before use. As sterilization methods implemented by hospitals, medical device manufacturers, etc., the following methods can be cited: after placing sterilized objects such as scalpels and forceps into sterilized packaging bodies and sealing them, they are sterilized using gas sterilization, high-pressure steam sterilization, radiation sterilization, etc. The gas sterilization method is to place the packaged object in a pressure-resistant container to reduce the pressure in the container, and after the air inside the package is discharged, the container is filled with ethylene oxide gas (EOG) and the like, and the gas is infiltrated into the interior of the package for sterilization. The high-pressure steam sterilization method is to use an autoclave to expose the packaged object to high-temperature steam, and repeatedly reduce pressure and increase pressure for sterilization. The radiation sterilization method is to irradiate radiation for sterilization. Among them, gas sterilization or high-pressure steam sterilization is mostly used for cost and simplicity.

[0003] The sterilized instruments are stored in the sterilized packaging body until they are used for surgery, etc., and are opened for use during surgery or treatment. When opening, the packaging is usually opened in a manner that is easy for doctors and surgeons in hospitals to open even with gloves, such as a peeling method or a tearing method. The peeling method sterilization packaging body is manufactured by bonding two rectangular sheets on the front and back in a peelable manner. The tearing method sterilization packaging body is manufactured using an easy-to-split (easy to tear and open) sheet.

[0004] Sterilization packages used in the aforementioned gas sterilization and high-pressure steam sterilization methods must be air-permeable due to their sterilization methods. Sterilization packages used in radiation sterilization methods may also volatilize residual solvents and odors contained in the packaged materials during sterilization, so they are preferably air-permeable. Therefore, air-permeable sheets are used for sterilization packages.

[0005] Heat sealing sheets that are sealed by heat compression are used in sterilized packaging bodies in bag-like and container-like forms. For example, a heat sealing sheet that forms a lid of a molded container such as a tray or a cup is heat-compressed to a flange portion surrounding an opening, thereby sealing the container.

[0006] The heat-sealing sheet is required to ensure air permeability that allows sterilization and to achieve complete sealing (maintenance of the sterilized state) after sterilization.

[0007] Patent Document 1 proposes to ensure air permeability by forming the heat-adhesive layer of the heat-sealing sheet into a grid shape. However, the flange portion of the heat-sealing sheet to be heat-pressed is generally narrow, and the completeness of the sealing of the grid-shaped heat-adhesive layer is questionable.

[0008] On the other hand, Patent Document 2 proposes a heat sealing sheet in which a granular thermoplastic resin is blended in a heat adhesive layer, thereby ensuring air permeability and making the heat adhesive layer so-called full-surface coating.

[0009] For these heat-sealing sheets, when paper is used as the air-permeable substrate, the mass per unit area must be limited to ensure sufficient air permeability, which results in strength constraints. In addition, there is a concern about the generation of lint due to the detachment of pulp fibers. The current situation is that although it is suitable for sterilization of small / light medical devices or general medical devices, it is not suitable for large medical devices such as heavy medical devices, bed sheets, isolation gowns, and advanced medical devices such as catheters.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application Publication No. 2017-43866

[0013] Patent Document 2: Japanese Patent Application Publication No. 2017-20130 Summary of the invention

[0014] Problem that the invention aims to solve

[0015] The object of the present invention is to provide an excellent heat-sealing sheet having sufficient thermal adhesiveness and air permeability throughout the heat-sealing surface, high strength, and suppressing the generation of lint (fiber fluff) to a small amount, a method for manufacturing the same, and a sterilization packaging body using the same.

[0016] Solutions for solving problems

[0017] The present invention has the following aspects.

[0018] <1> A heat sealing sheet comprising: one or more thermoplastic resin fiber nonwoven fabric layers A, and one or more thermoplastic resin fiber nonwoven fabric layers B,

[0019] The thermoplastic resin fiber nonwoven fabric layer B contains a low melting point polyester resin, polyester fibers and polyethylene resin, and the mass ratio of the low melting point polyester resin, polyester fibers and polyethylene resin (low melting point polyester resin: polyester fibers: polyethylene resin) is 13.75:11.25:75 to 41.25:33.75:25.

[0020] The heat seal sheet has a Wangyan air permeability of 700 seconds or less as measured in accordance with JIS P 8117:2009, and

[0021] The heat seal sheet has a tear strength of 700 mN or more as measured in accordance with JIS P 8116:2000.

[0022] <2> The heat-sealing sheet according to <1>, wherein the thermoplastic resin fiber nonwoven fabric layer A is a nonwoven fabric layer derived from at least one selected from the group consisting of spunbonded nonwoven fabric, thermally bonded nonwoven fabric, chemically bonded nonwoven fabric, needle-punched nonwoven fabric, spunlace nonwoven fabric, meltblown nonwoven fabric and wet-laid nonwoven fabric.

[0023] <3> The heat-sealing sheet according to <1> or <2>, wherein the thermoplastic resin fiber nonwoven fabric layer A includes at least one selected from the group consisting of polypropylene resin fibers, polyester fibers, and polyamide fibers.

[0024] <4> The heat-sealing sheet according to any one of <1> to <3>, wherein the thermoplastic resin fiber nonwoven fabric layer A has residual fiber shapes.

[0025] <5> The heat-sealing sheet according to any one of <1> to <4>, wherein the peel strength when the heat-sealing sheet and a sterilization packaging material such as paper, film or sterilization molded container are peeled 180 degrees at a peeling speed of 300 mm / min in accordance with JIS P 8113:2006 is 1.0 / 15 mm or more and 15 N / 15 mm or less.

[0026] <6> The heat sealing sheet according to any one of <1> to <5>, having a mass per unit area of ​​30 g / m 2 Above and 150g / m 2 the following.

[0027] <7> The heat-sealing sheet according to any one of <1> to <6>, wherein the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B are laminated such that the thermoplastic resin fiber nonwoven fabric layer B serves as a surface layer.

[0028] <8> A sterilization packaging body, wherein the heat sealing sheet according to any one of <1> to <7> and a sterilization packaging material are thermally compressed.

[0029] <9> A method for producing a heat-sealing sheet according to any one of <1> to <7>, the method comprising the following steps 1 to 3 in order.

[0030] Step 1: Step of preparing thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b

[0031] Step 2: A step of laminating one or more layers of thermoplastic resin fiber nonwoven fabric a and one or more layers of thermoplastic resin fiber nonwoven fabric b to obtain a laminate

[0032] Step 3: Step of heat-sealing the laminated body obtained in step 2

[0033] <10> The method for producing a heat-sealing sheet according to <9>, wherein the thermoplastic resin fiber nonwoven fabric b contains 25 to 75% by mass of polyethylene multi-branched fibers.

[0034] <11> The method for producing a heat-sealing sheet according to <9> or <10>, wherein the thermoplastic resin fiber nonwoven fabric b contains core-sheath structured polyester fibers.

[0035] <12> The method for producing a heat-sealing sheet according to any one of <9> to <11>, wherein the thermoplastic resin fiber nonwoven fabric b is a nonwoven fabric obtained by a wet papermaking method.

[0036] Effects of the Invention

[0037] The heat-sealing sheet of the present invention has sufficient thermal adhesiveness and air permeability throughout the heat-sealing surface, is high in strength, and suppresses the amount of lint generated to a small level, and is excellent as a sterilized medical packaging material. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a cross-sectional view of one embodiment of a sterilization package.

[0039] Figure 2 It is a cross-sectional view of one embodiment of a heat sealing sheet.

[0040] Figure 3 It is a cross-sectional view of another embodiment of a heat sealing sheet.

[0041] Figure 4 It is a cross-sectional view of another embodiment of a heat sealing sheet. DETAILED DESCRIPTION

[0042] In the present invention, the term "sheet" refers to a general term for thin sheet bodies such as sheets, films, nonwoven fabrics, or laminates thereof.

[0043] The "Oken air permeability" is a value measured in accordance with JIS P 8117:2009.

[0044] The "weight per unit area" is a value measured in accordance with JIS P 8124:2011.

[0045] The "melting point" is a melting peak temperature measured in accordance with JIS K 7121:1987.

[0046] The "tear strength" is a geometric mean of the values ​​measured in each of the longitudinal direction and the transverse direction of the sheet measured in accordance with JIS P 8116:2000.

[0047] Below, refer to Figure 1 to Figure 4 , an embodiment of a heat sealing sheet and a sterilization packaging body is described.

[0048] [Heat-sealed sheet and sterilized packaging]

[0049] The sterilization packaging body (11) comprises a heat sealing sheet (21) and an adherend (31) ( Figure 1 ).

[0050] The heat sealing sheet (21) comprises: one or more layers of thermoplastic resin fiber nonwoven fabric layer A (22), and one or more layers of thermoplastic resin fiber nonwoven fabric layer B (23) ( Figure 2 and 3 ). As long as the heat sealing sheet (21) has one or more layers of thermoplastic resin fiber nonwoven fabric layer A (22) and one or more layers of thermoplastic resin fiber nonwoven fabric layer B (23), it may also have a thermoplastic resin fiber nonwoven fabric layer C (41) different from the thermoplastic resin fiber nonwoven fabric layer A (22) and the thermoplastic resin fiber nonwoven fabric layer B (23) ( Figure 4 ).

[0051] As described later, the heat-sealing sheet (21) is preferably obtained by stacking and thermally fusing one or more layers of thermoplastic resin fiber nonwoven fabric a and one or more layers of thermoplastic resin fiber nonwoven fabric b, wherein the thermoplastic resin fiber nonwoven fabric layer A is a layer derived from the thermoplastic resin fiber nonwoven fabric a, and the thermoplastic resin fiber nonwoven fabric layer B is a layer derived from the thermoplastic resin fiber nonwoven fabric b.

[0052] The heat sealing sheet (21) has an Oken air permeability of 700 seconds or less measured in accordance with JIS P 8117:2009 and a tear strength of 700 mN or more measured in accordance with JIS P 8116:2000.

[0053] Furthermore, the thermoplastic resin fiber nonwoven fabric layer B contains a low melting point polyester resin, polyester fibers and polyethylene resin, and the mass ratio of the low melting point polyester resin, polyester fibers and polyethylene resin (low melting point polyester resin: polyester fibers: polyethylene resin) is 13.75:11.25:75 to 41.25:33.75:25.

[0054] According to the heat seal sheet of this embodiment, the heat seal sheet has sufficient thermal adhesiveness and air permeability over the entire heat seal surface, has high strength, particularly high tear strength, and suppresses the amount of lint generated.

[0055] The detailed reasons for obtaining the above effects are not clear, but it is believed that part of them are as follows. That is, it is believed that by having a Wangyan air permeability of 700 seconds or less, appropriate air permeability can be obtained, and by having a tear strength of 700 mN or more, a heat-sealing sheet with high strength can be obtained. In addition, by having a specific resin composition of the thermoplastic resin fiber nonwoven fabric layer B, the heat adhesiveness is excellent, and the fuzzing of fibers called lint and the generation of fiber scraps falling therefrom are suppressed when the package is opened.

[0056] (Wang Yan style air permeability)

[0057] The O-type air permeability of the heat-sealing sheet (21) measured in accordance with JIS P 8117:2009 is 700 seconds or less. If the O-type air permeability is 700 seconds or less, ethylene oxide gas sterilization can be applied, which is preferred. The O-type air permeability of the heat-sealing sheet (21) is more preferably 300 seconds or less, further preferably 150 seconds or less, and further preferably 100 seconds or less. The lower limit of the O-type air permeability is not particularly limited.

[0058] (Tear Strength)

[0059] The tear strength of the heat-sealing sheet (21) measured in accordance with JIS P 8116:2000 is 700 mN or more. If the tear strength is 700 mN or more, it can be used as a sterilization packaging material for larger medical instruments and medical devices with large mass, so it is preferred. The tear strength of the heat-sealing sheet (21) is more preferably 800 mN or more, further preferably 1000 mN or more, further preferably 1500 mN or more, and particularly preferably 2000 mN or more. The upper limit of the tear strength is not particularly limited, but from the viewpoint of ease of manufacture, it is preferably 5000 mN or less, and more preferably 4000 mN or less.

[0060] (Mass per unit area)

[0061] From the viewpoint of easy manufacturing and obtaining appropriate heat seal strength and tear strength, the weight per unit area of ​​the heat seal sheet of this embodiment is preferably 30 g / m 2 More preferably 50 g / m 2 More preferably 70g / m 2 More than 300g / m 2 Below, more preferably 200g / m 2 Below, more preferably 150g / m 2 Below, more preferably 100g / m 2 the following.

[0062] By adjusting the basis weights of the thermoplastic resin fiber nonwoven fabric a and the thermoplastic resin fiber nonwoven fabric b to be within an appropriate range, the basis weight of the heat sealing sheet can be set to be within a desired range.

[0063] <Thermoplastic resin fiber nonwoven fabric layer A>

[0064] The heat sealing sheet (21) of this embodiment has one or more thermoplastic resin fiber nonwoven fabric layers A. The thermoplastic resin fiber nonwoven fabric layer A (22) is a layer of thermoplastic resin fiber nonwoven fabric a obtained by forming one or more thermoplastic resin fiber groups a into a sheet using various known methods.

[0065] As a method of forming a sheet, for example, spunbonding, thermal bonding, chemical bonding, needle punching, spunlace, meltblowing, wet papermaking, etc. can be cited. Among them, spunbonding is preferred because the sheet is composed of continuous fibers, so it has high strength and is not easy to cause fiber detachment. In addition, wet papermaking is preferred because it can obtain a uniform nonwoven fabric.

[0066] (Thermoplastic resin fiber nonwoven fabric a)

[0067] As the thermoplastic resin fiber group a constituting the thermoplastic resin fiber nonwoven fabric a, various known substances can be used. Fibers having a melting point higher than the melting point (not specifically limited, for example, below 150°C) of the thermoplastic resin fiber group b used in the aforementioned thermoplastic resin fiber nonwoven fabric layer B (23) are preferred because they can maintain their fiber shape after heat lamination and can easily obtain high tear strength (tear strength obtained by the Elmendorf Method in which the tear strength of a portion into which a crack has been introduced in advance).

[0068] Examples of the fibers constituting the thermoplastic resin fibers a group include polypropylene fibers, polyester fibers, and polyamide fibers, but are not limited thereto.

[0069] That is, the thermoplastic resin fiber nonwoven fabric a and the thermoplastic resin fiber nonwoven fabric layer A preferably include at least one selected from the group consisting of polypropylene resin fibers, polyester fibers, and polyamide fibers, and more preferably include polypropylene resin fibers or polyester fibers.

[0070] From the viewpoint of improving the interlayer adhesion between the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B, polypropylene fibers are preferred.

[0071] In addition, by including polyester fibers, when the thermoplastic resin fiber nonwoven fabric a and the thermoplastic resin fiber nonwoven fabric b are stacked, as described later, the melting point difference between the resin constituting the thermoplastic resin fiber nonwoven fabric a and the resin constituting the thermoplastic resin fiber nonwoven fabric b can be increased, and the melting of the resin constituting the thermoplastic resin fiber nonwoven fabric a during heat lamination can be suppressed. Since the resin shape is better maintained in the thermoplastic resin fiber nonwoven fabric layer A, the strength as a heat-sealed sheet is improved, so it is preferred.

[0072] It should be noted that the thermoplastic resin fibers constituting the thermoplastic resin fiber nonwoven fabric a are preferably not melted in the heat-sealing step described later, and in the heat-sealed sheet (21), the fiber shape is preferably left in the thermoplastic resin fiber nonwoven fabric layer A.

[0073] When the thermoplastic resin fiber nonwoven fabric layer A (22) is used as the surface layer of the heat sealing sheet (21), polypropylene resin fibers that can easily suppress the fuzzing of the surface during heat lamination are preferably used as the thermoplastic resin group a.

[0074] Furthermore, natural pulp fibers, regenerated fibers, and other chemical fibers may be used in combination within a range not impairing the object of the present invention.

[0075] The average fiber diameter of the thermoplastic resin fibers a group is not particularly limited, and is, for example, 0.5 μm or more and 50 μm or less, and preferably 5 μm or more and 30 μm or less.

[0076] The thermoplastic resin fiber nonwoven fabric a is preferably any nonwoven fabric selected from the group consisting of spunbonded nonwoven fabrics, thermally bonded nonwoven fabrics, chemically bonded nonwoven fabrics, needle-punched nonwoven fabrics, spunlace nonwoven fabrics, meltblown nonwoven fabrics and wet nonwoven fabrics, more preferably any nonwoven fabric selected from the group consisting of meltblown nonwoven fabrics, spunbonded nonwoven fabrics and wet nonwoven fabrics, and further preferably spunbonded nonwoven fabrics or wet nonwoven fabrics.

[0077] The spunbonded nonwoven fabric is preferably used in terms of obtaining a heat-sealing sheet having excellent strength because it is formed by melting a thermoplastic resin and discharging the resulting nonwoven fabric in a continuous long fiber form.

[0078] In view of high uniformity, wet-laid nonwoven fabric is preferred.

[0079] The mass per unit area of ​​the thermoplastic resin fiber nonwoven fabric a and the thermoplastic resin fiber nonwoven fabric layer A (22) is not particularly limited, and is, for example, 5 g / m 2 Above and 100g / m 2 The thickness is adjusted within the range of about 10 g / m2, and from the viewpoint of obtaining sufficient thermal adhesiveness and air permeability and tear strength, it is preferably 10 g / m2. 2 Above and 80g / m 2 Below, more preferably 20g / m 2 Above and 50g / m 2 the following.

[0080] In addition, when the heat sealing sheet has two or more thermoplastic resin fiber nonwoven fabric layers A (22), the above-mentioned preferred range of the basis weight is the preferred range of the basis weight of each layer.

[0081] The thermoplastic resin fiber nonwoven fabric layer A (22) may be a single layer or a plurality of layers. In addition, the lamination method with the thermoplastic resin fiber nonwoven fabric layer B (23) and the thermoplastic resin fiber nonwoven fabric layer C (41) may be implemented in any order.

[0082] <Thermoplastic resin fiber nonwoven fabric layer B>

[0083] The thermoplastic resin fiber nonwoven fabric layer B (23) is a layer made from a thermoplastic resin fiber nonwoven fabric b obtained by forming a sheet of one or more thermoplastic resin fiber groups b by various known methods.

[0084] The thermoplastic resin fiber nonwoven fabric layer B contains low melting point polyester resin, polyester fiber and polyethylene resin, and the mass ratio of low melting point polyester resin, polyester fiber and polyethylene resin (low melting point polyester resin: polyester fiber: polyethylene resin) is 13.75:11.25:75 to 41.25:33.75:25.

[0085] (thermoplastic resin fiber nonwoven fabric b)

[0086] As the thermoplastic resin fiber group b constituting the thermoplastic resin fiber nonwoven fabric b, one or more thermoplastic resin fibers can be used. In order to achieve adhesion with the thermoplastic resin fiber nonwoven fabric layer A (22) after heat lamination and heat sealability of the heat-sealing sheet, the fibers constituting the thermoplastic resin fiber group b preferably contain fibers having a melting point lower than 150°C.

[0087] The fibers constituting the thermoplastic resin fibers b group may have a single structure or a core-sheath structure of two or more layers. In the case of a core-sheath structure, the melting point of the sheath resin is preferably lower than 150°C, and the melting point of the core resin may be 150°C or higher.

[0088] As the thermoplastic resin fiber b group, for example, various polyethylene resin fibers, polyethylene-vinyl acetate resin fibers, low melting point polyester resin fibers, or composite fibers with a core-sheath structure in which the core is a common polyester resin and the sheath is the aforementioned various polyethylene resin fibers, polyethylene-vinyl acetate resin, or composite resins with a core-sheath structure in which the core is a common polyester resin and the sheath is a low melting point polyester resin. In addition, these resin fibers may also be multi-branched structures.

[0089] Among them, polyester fibers and polyethylene fibers having a core-sheath structure in which low-melting polyester is used in the sheath part and ordinary polyester is used in the core part are preferably used because they have excellent heat lamination properties and heat sealing properties with the thermoplastic resin fiber nonwoven fabric a.

[0090] Here, the melting point of the low melting point polyester used in the sheath is lower than 150° C., preferably 140° C. or lower, more preferably 130° C. or lower, and further preferably 120° C. or lower. On the other hand, the melting point of the polyester used in the core is 150° C. or higher, preferably 180° C. or higher, more preferably 200° C. or higher, and further preferably 240° C. or higher. As the polyester used in the core, for example, polyethylene terephthalate is exemplified.

[0091] In addition, polyethylene fibers are preferably polyethylene multi-branched fibers obtained by pulping polyethylene, because they can be wet-made to produce thermoplastic resin fiber nonwoven fabric b. Wet-made thermoplastic resin fiber nonwoven fabric b can produce a nonwoven fabric with better texture, better uniformity, and more density, so it is preferred.

[0092] It should be noted that, when the thermoplastic resin fiber nonwoven fabric b is a nonwoven fabric obtained by using a core-sheath structure polyester fiber in which a low-melting polyester is used in the sheath part and a normal polyester is used in the core part, and polyethylene fibers, in the thermoplastic resin fiber nonwoven fabric layer B after heat fusion, the low-melting polyester resin in the sheath part of the core-sheath structure polyester fiber and a part of the polyethylene fibers are melted, and therefore, the fiber shape may not be maintained. It should be noted that it is not limited to the case where the aforementioned low-melting polyester resin and polyethylene fibers are completely melted, as long as at least a part of them is melted.

[0093] The thermoplastic resin fiber nonwoven fabric b is preferably a nonwoven fabric obtained by wet papermaking, and is preferably obtained by wet papermaking a core-sheath structure polyester fiber using a low melting point polyester in the sheath part and a normal polyester in the core part and polyethylene multi-branched fiber.

[0094] Thermoplastic resin fiber nonwoven fabric b preferably contains 25% by mass or more and 75% by mass or less of core-sheath structure polyester fibers in which low-melting point polyester is used in the sheath part and ordinary polyester is used in the core part, more preferably 30% by mass or more and 70% by mass or less, and further preferably 40% by mass or more and 60% by mass or less.

[0095] The mass ratio of the sheath to the core (sheath / core) is preferably 20 / 80 or more and 80 / 20 or less, more preferably 30 / 70 or more and 70 / 30 or less, and further preferably 40 / 60 or more and 60 / 40 or less.

[0096] Examples of core-sheath structure polyester fibers in which low-melting-point polyester is used in the sheath and ordinary polyester is used in the core include Tepyrus series manufactured by TEIJIN FRONTIER CO., LTD. and PET-based binder fibers manufactured by KURARAY CO., LTD.

[0097] The thermoplastic resin fiber nonwoven fabric b preferably contains 25% by mass to 75% by mass of polyethylene multi-branched fibers, more preferably 30% by mass to 70% by mass, and even more preferably 35% by mass to 60% by mass.

[0098] As polyethylene multi-branched fibers obtained by pulping polyethylene, there is exemplified the SWP (registered trademark) series manufactured by Mitsui Chemicals, Inc.

[0099] In the thermoplastic resin fiber nonwoven fabric layer B derived from the thermoplastic resin fiber nonwoven fabric b obtained by using these thermoplastic resin fiber b groups, as described above, the mass ratio of the low melting point polyester resin, the polyester fiber and the polyethylene resin (low melting point polyester resin: polyester fiber: polyethylene resin) is 13.75:11.25:75 to 41.25:33.75:25. It should be noted that from the viewpoint of preferably having a fiber shape, the polyester fiber is referred to as "polyester fiber", while on the other hand, since at least a part of the low melting point polyester and polyethylene constituting the thermoplastic resin fiber are melted, they are referred to as "low melting point polyester resin" and "polyethylene resin", respectively.

[0100] When the total amount of the low-melting polyester resin, the polyester fiber and the polyethylene resin is 100 parts by mass, the content of the low-melting polyester resin is 13.75 parts by mass or more and 41.25 parts by mass or less, preferably 16.5 parts by mass or more and 38.5 parts by mass or less, and more preferably 22 parts by mass or more and 33 parts by mass or less. It should be noted that the low-melting polyester resin refers to a polyester resin having a melting point of less than 150° C. as described above.

[0101] In addition, when the total amount of the low melting point polyester resin, the polyester fiber and the polyethylene resin is 100 parts by mass, the content of the polyester resin is 11.25 parts by mass or more and 33.75 parts by mass or less, preferably 13.5 parts by mass or more and 31.5 parts by mass or less, and more preferably 18 parts by mass or more and 27 parts by mass or less. It should be noted that the melting point of the "polyester fiber" in this embodiment is 150° C. or more, preferably 180° C. or more, more preferably 200° C. or more, and further preferably 240° C. or more, and an example thereof is polyethylene terephthalate.

[0102] Furthermore, when the total amount of the low-melting point polyester resin, the polyester fiber and the polyethylene resin is 100 parts by mass, the content of the polyethylene resin is 25 parts by mass or more and 75 parts by mass or less, preferably 30 parts by mass or more and 70 parts by mass or less, and more preferably 35 parts by mass or more and 60 parts by mass or less.

[0103] In the thermoplastic resin fiber nonwoven fabric layer B, the total content of the low-melting point polyester resin, polyester fiber and polyethylene resin is 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and further preferably 85% by mass or more, and the upper limit is 100% by mass or less.

[0104] In addition, within the scope of not impairing the purpose of the present invention, natural pulp fibers, recycled fibers, and other chemical fibers can also be used in combination as the thermoplastic resin fiber group b. It should be noted that, from the perspective of reducing environmental load and improving strength, natural pulp can also be used in combination, and examples of natural pulp include wood pulp (conifer pulp, broadleaf pulp, etc.), non-wood pulp (hemp pulp, cotton pulp, grass pulp, etc.), etc.

[0105] The fiber diameter of the fibers used in the thermoplastic resin fiber nonwoven fabric b is not particularly limited, and is, for example, 1 μm or more and 60 μm or less, and preferably 1 μm or more and 40 μm or less.

[0106] The mass per unit area of ​​the thermoplastic resin fiber nonwoven fabric b and the thermoplastic resin fiber nonwoven fabric layer B (23) is not particularly limited, and is, for example, 5 g / m 2 Above and 100g / m 2 The following range is adjusted, and from the viewpoint of obtaining sufficient thermal adhesiveness, air permeability and tear strength, 10 g / m 2 Above and 80g / m 2 Below, more preferably 15g / m 2 Above and 60g / m 2 the following.

[0107] In addition, when the heat sealing sheet has two or more thermoplastic resin fiber nonwoven fabric layers B (23), the above-mentioned preferred range of the basis weight is the preferred range of the basis weight of each layer.

[0108] The thermoplastic resin fiber nonwoven fabric layer B (23) may be a single layer or a plurality of layers. As described above, the lamination method with the thermoplastic resin fiber nonwoven fabric layer A (22) may be carried out in any order.

[0109] As a method for producing the thermoplastic resin fiber nonwoven fabric b, various known methods can be applied. Among them, the wet papermaking method is preferred because it is easy to obtain good texture even with a low mass per unit area and it is difficult to produce pinholes that impair the antibacterial properties of the heat sealing sheet.

[0110] Examples of wet papermaking methods include methods using a Fourdrinier paper machine, a short-wire paper machine, a cylinder paper machine, an inclined paper machine, etc. Among them, cylinder paper machines and inclined paper machines are preferred because they can use materials with relatively long fibers, and inclined paper machines are more preferred.

[0111] Various dispersants, surfactants, binders, and other internal additives may be added to the raw material slurry for the purpose of adjusting the texture.

[0112] The drying method of the thermoplastic resin fiber nonwoven fabric b after wet papermaking is also not particularly limited, and a multi-cylinder dryer, a Yankee dryer, a hot air dryer, an infrared dryer, etc. can be used. When a multi-cylinder dryer or a Yankee dryer is used, it is preferred to set the drying temperature to a temperature below the melting point of the thermoplastic resin fiber or to coat the surface of the multi-cylinder dryer or the Yankee dryer with a fluororesin in order to prevent surface contamination caused by the adhesion of the thermoplastic resin.

[0113] <Thermoplastic resin fiber nonwoven fabric layer C>

[0114] The thermoplastic resin fiber nonwoven fabric layer C (41) is a layer made from a thermoplastic resin fiber nonwoven fabric c obtained by forming a sheet of one or more thermoplastic resin fiber groups c by various known methods.

[0115] The thermoplastic resin fiber nonwoven fabric layer C is a layer provided on the side not subjected to heat sealing in the heat sealing sheet of the present embodiment.

[0116] (Thermoplastic resin fiber nonwoven fabric c)

[0117] As the thermoplastic resin fiber group c constituting the thermoplastic resin fiber nonwoven fabric c, one or more fibers can be used. In order to bond with the thermoplastic resin fiber nonwoven fabric layer A (22) after heat lamination, the fibers constituting the thermoplastic resin fiber group c preferably contain thermoplastic resin fibers having a melting point lower than 150°C.

[0118] As the thermoplastic resin fiber c group, for example, various polyethylene resin fibers, polyethylene-vinyl acetate resin fibers, low melting point polyester resin fibers, or composite fibers with a core structure of a common polyester resin and a sheath of the aforementioned various polyethylene resin fibers, polyethylene-vinyl acetate resin, and composite resins with a core structure of a common polyester resin and a sheath of a low melting point polyester resin can be cited. In addition, these resin fibers can also use those with a multi-branched structure. In addition, natural pulp fibers, recycled fibers, and other chemical fibers can be used in combination. As natural pulp, examples include wood pulp (conifer pulp, broadleaf pulp, etc.), non-wood pulp (hemp pulp, cotton pulp, grass pulp, etc.), etc.

[0119] Among these, the fiber group constituting the thermoplastic resin fiber nonwoven fabric c preferably contains natural pulp. When performing heat fusion (heat lamination) in step 3 described later, if tension is applied in a heated state, the mesh of the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B may expand and the air permeability may decrease. The thermoplastic resin fiber nonwoven fabric c contains natural pulp, so that the mesh expansion is suppressed and the decrease in air permeability is suppressed, which is preferred.

[0120] Furthermore, the thermoplastic resin fiber nonwoven fabric b shrinks during heat fusion, and the heat-sealed sheet may curl as a result. However, the use of the thermoplastic resin fiber nonwoven fabric c containing pulp is preferred because curling is suppressed.

[0121] The content of natural pulp in the thermoplastic resin fiber nonwoven fabric c is preferably 5% by mass or more, more preferably 10% by mass or more.

[0122] The mass per unit area of ​​the thermoplastic resin fiber nonwoven fabric c and the thermoplastic resin fiber nonwoven fabric layer C (41) is not particularly limited, and is, for example, 10 g / m 2 Above and 100g / m 2 The following range is adjusted, and from the viewpoint of obtaining sufficient thermal adhesiveness, air permeability and tear strength, 15 g / m 2 Above and 80g / m 2 Below, more preferably 20g / m 2 Above and 60g / m 2 the following.

[0123] It should be noted that, as described later, in the case of a laminated structure of b / a / c, the unit area mass of the thermoplastic resin fiber nonwoven fabric c and the thermoplastic resin fiber nonwoven fabric layer C (41) is preferably greater than the unit area mass of the thermoplastic resin fiber nonwoven fabric b and the thermoplastic resin fiber nonwoven fabric layer B (23), and more preferably greater than 5 g / m 2 By adopting the above configuration, curling of the heat sealing paper due to curling of the thermoplastic resin fiber nonwoven fabric b and the thermoplastic resin fiber nonwoven fabric layer B (23) is suppressed, which is preferable.

[0124] [Method for producing heat seal sheet]

[0125] The method for producing the heat-sealing sheet of the present embodiment preferably includes the following steps 1 to 3 in order.

[0126] Step 1: Step of preparing thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b

[0127] Step 2: A step of laminating one or more layers of thermoplastic resin fiber nonwoven fabric a and one or more layers of thermoplastic resin fiber nonwoven fabric b to obtain a laminate

[0128] Step 3: Step of heat-sealing the laminated body obtained in step 2

[0129] <Process 1>

[0130] Step 1 is a step of preparing thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b.

[0131] Thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b may be prepared according to the above-mentioned method.

[0132] <Process 2>

[0133] Step 2 is a step of laminating one or more layers of thermoplastic resin fiber nonwoven fabric a and one or more layers of thermoplastic resin fiber nonwoven fabric b to obtain a laminate.

[0134] Regarding the lamination method of thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b, from the viewpoint of heat sealing properties, the lamination order is not limited except that the lamination is performed in a manner in which any outermost surface of the front / back side becomes the thermoplastic resin fiber nonwoven fabric b. In addition, each layer can be a single layer or a multilayer of more than two layers.

[0135] Among these, in order to reduce curling after heat lamination, it is preferred that the front side / back side be symmetrical with respect to the center layer or in an order based thereon.

[0136] Therefore, it is preferred to have b / (a / b) n The present invention relates to a laminated structure of thermoplastic resin fiber nonwoven fabric b / thermoplastic resin fiber nonwoven fabric a / thermoplastic resin fiber nonwoven fabric b, a laminated structure of thermoplastic resin fiber nonwoven fabric b / a / b / a / b (n is an integer greater than 0), a laminated structure of thermoplastic resin fiber nonwoven fabric b / thermoplastic resin fiber nonwoven fabric a / thermoplastic resin fiber nonwoven fabric b, and a laminated structure of thermoplastic resin fiber nonwoven fabric b / a / b / a / b. Of these, a laminated structure of b / a / b or a laminated structure of b / a / b / a / b is preferred, and a laminated structure of b / a / b is more preferred from the viewpoint of ease of manufacture.

[0137] Alternatively, a three-layer structure of b / a / c may be formed. When the three-layer structure is formed, the curling after heat lamination can be reduced by reducing the unit area mass of the nonwoven fabric layer B with a high shrinkage rate caused by heat in the thermoplastic resin fiber nonwoven fabric b and the thermoplastic resin fiber nonwoven fabric c, which is preferred.

[0138] <Process 3>

[0139] Step 3 is a step of heat-sealing the laminate obtained in step 2. In step 3, the thermoplastic resin fiber nonwoven fabric a and the thermoplastic resin fiber nonwoven fabric b constituting the laminate are heat-sealed (heat-laminated).

[0140] The heat fusion step is performed by passing the laminate obtained in step 2 between two heating rolls.

[0141] The temperature of the heating roll is adjusted to be at least the melting point of the lowest melting point of the thermoplastic resin fibers used in the thermoplastic resin fiber nonwoven fabric b and at most the melting point of the lowest melting point of the thermoplastic resin fibers used in the thermoplastic resin fiber nonwoven fabric a + 20°C.

[0142] By setting the temperature of the heating roller to not less than the melting point of the thermoplastic resin fiber with the lowest melting point used in the thermoplastic resin fiber nonwoven fabric b, the effect of suppressing the fuzzing of the surface of the thermoplastic resin fiber nonwoven fabric b can be fully obtained, and the heat sealing strength can also be obtained. In addition, the occurrence of fuzzing and damage on the heat-bonded surface when peeling the adherend (31) can be suppressed. In addition, by setting the temperature of the heating roller to the melting point of the thermoplastic resin fiber with the lowest melting point used in the thermoplastic resin fiber nonwoven fabric a + 20°C or less, the fiber shape is maintained in the thermoplastic resin fiber nonwoven fabric layer A (22) after heat fusion, and sufficient tear strength can be obtained, which is preferred.

[0143] Furthermore, it is preferred to coat the surface of the heating roller with a fluorine resin in order to prevent surface contamination due to adhesion of the thermoplastic resin.

[0144] The surface temperature of the heating roller may be the same or different at the top and bottom. In addition, heat fusion may be performed with one nip or more than two nips.

[0145] When there are two or more nips, the process may be performed in one pass or in two or more passes.

[0146] When the laminate obtained in step 2 has three or more layers, heat fusion may be performed on all layers simultaneously, or heat fusion may be performed on a part of the layers first and then on other layers.

[0147] During heat fusion, before pressurization, a step of heating the thermoplastic resin fiber nonwoven fabric a and / or the thermoplastic resin fiber nonwoven fabric b with a preheater or the like may be added to provide residual heat before contacting the thermoplastic resin fiber nonwoven fabric a and / or the thermoplastic resin fiber nonwoven fabric b with the heating roll.

[0148] In addition, well-known techniques can be applied.

[0149] [Effects]

[0150] The heat-sealing sheet (21) of the present invention is obtained by heat-melting (heat laminating) thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b. The entire heat-sealing sheet has sufficient thermal adhesiveness and breathability and high strength. In addition, the amount of lint generated is suppressed to a small amount, and it is excellent as a sterilized medical packaging material.

[0151] [use]

[0152] The heat sealing sheet (21) is used, for example, for a sterilized packaging body (11). A portion of the heat sealing sheet (21) and a portion of an adherend (31) such as a wrapping paper, laminated paper, film, or a sterilization molded container are overlapped and heat-compressed in a manner to form a space inside, thereby forming a sterilized packaging body in which the heat sealing sheet (21) and the adherend (31) are heat-compressed.

[0153] Examples of the film or sterilization molded container include films or sterilization molded containers made of polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polystyrene, ethylene-vinyl acetate copolymer resins, ethylene-acrylic acid copolymer resins, or laminates thereof.

[0154] The molded container for sterilization typically has one or more recessed portions for storing the stored contents. In this case, the heat sealing sheet (21) is typically used as a cover material for sealing the openings of the one or more recessed portions.

[0155] As the adherend to be thermally compressed with the heat sealing sheet (21), a molded container for sterilization is preferred because sufficient peel strength can be achieved without causing damage to the substrate even with a relatively narrow sealing width.

[0156] The sterilization package (11) forms a space for storing items such as medical instruments by means of a heat-sealing sheet (21) and an adherend (31) that are heat-pressed together. The heat-sealing sheet (21) and the adherend (31) are heat-pressed together after the items are stored.

[0157] The medical instruments to be stored are not particularly limited as long as they are required to be sterilized before use. Specific examples include injection needles, syringes, catheters, gloves, scalpels, forceps, tweezers, scissors, gauze, bandages, and the like.

[0158] The sterilization package is sterilized in a state where the stored items are stored. For example, the sterilization is performed by a sterilization method such as autoclave, ethylene oxide gas (EOG) sterilization, electron beam sterilization, gamma ray sterilization, etc. Furthermore, when the stored items are used, the heat sealing sheet (21) is peeled off from the adherend and the stored items are taken out.

[0159] The use of the heat-sealing sheet (21) is not limited to sterilized packaging bodies, but can also be used for packaging of food, various preservatives such as desiccants and deoxidizers, general industrial products, etc.

[0160] In addition, printing processing can be performed on either the front side or the back side, or on the outermost surfaces of both sides.

[0161] In the sterilized packaging body (11) of the heat-sealing sheet (21) and the adherend (31), the peel strength when the heat-sealing sheet (21) and the adherend (31) are peeled off at 180° at a peeling speed of 300 mm / min is preferably 1.0 N / 15 mm or more and 15 N / 15 mm or less, more preferably 1.5 N / 15 mm or more and 12 N / 15 mm or less, further preferably 2.0 N / 15 mm or more and 10.5 N / 15 mm or less, further preferably 4.0 N / 15 mm or more and 10.5 N / 15 mm or less, particularly preferably 4.5 N / 15 mm or more and 10.5 N / 15 mm or less, and most preferably 5.0 N / 15 mm or more and 7.5 N / 15 mm or less. If the peel strength is within the above range, the balance between easy peelability and heat sealing property is excellent.

[0162] The heat seal peel strength was measured by the method described in Examples.

[0163] The heat seal peel strength can be adjusted to the desired range by setting the unit area mass of the thermoplastic resin fiber nonwoven fabric layer B (23) constituting the heat seal cover, the content of polyethylene resin in the thermoplastic resin fiber nonwoven fabric layer B (23), the heat sealing conditions in the heat sealing process of the laminate when manufacturing the heat sealing sheet, and the heat sealing conditions with the adherend, etc. to appropriate ranges.

[0164] Example

[0165] The present invention is specifically described below by listing examples. It should be noted that the present invention is not limited by these examples. It should be noted that, unless otherwise specified, % means mass % and part means mass part.

[0166] [Examples 1 to 7, Comparative Examples 1 to 3]

[0167] <Manufacturing of thermoplastic resin fiber nonwoven fabric b>

[0168] The predetermined amounts of polyethylene multi-branched fibers (trade name: SWP (registered trademark) E400, melting point 135°C, average fiber length 0.9 mm, fiber diameter about 1 to 30 μm, manufactured by Mitsui Chemicals, Inc.), core-sheath structure polyester fibers (trade name: Tepyrus (registered trademark) TJ04CN, fineness 1.1 dtex, fiber length 5 mm, fiber diameter about 10 μm, sheath melting point 110°C, core (polyethylene terephthalate) melting point 260°C, sheath / core mass ratio = 55 / 45, manufactured by TEIJINFRONTIER CO., LTD.), hemp pulp (JIS P The raw material slurry was obtained by mixing and stirring the raw material slurry with 0.5 parts by mass of a modified polyester resin dispersant (trade name: SR-1800R, manufactured by Takamatsu Oil & Fats Co., Ltd.) based on 100 parts by mass of the total fiber.

[0169] The raw material slurry was made into paper using a wet inclined paper machine and dried in a Yankee dryer at a surface temperature of 105°C. In Examples 1 to 6 and Comparative Examples 1 to 3, a mass per unit area of ​​25 g / m 2 In Example 7, the thermoplastic resin fiber nonwoven fabric b was obtained with a mass per unit area of ​​35 g / m 2 Thermoplastic resin fiber non-woven fabric b.

[0170] <Manufacturing of heat sealing sheets>

[0171] In Examples 1 to 5 and Comparative Examples 1 to 3, the thermoplastic resin fiber nonwoven fabric b obtained above and the polypropylene spunbonded nonwoven fabric a (fiber diameter of about 15 μm, mass per unit area of ​​30 g / m 2 The three layers of thermoplastic resin fiber nonwoven fabric b were overlapped and subjected to heat lamination treatment in a heat laminating machine having a heating roller with a fluorine-coated surface, with the roller temperature of the upper and lower rollers set to 150°C, to obtain a unit area mass of 80 g / m 2 The heat sealing sheets of Examples 1 to 5 and Comparative Examples 1 to 3.

[0172] In Example 6, a polyester spunbond nonwoven fabric (fiber diameter about 12 μm, mass per unit area 25 g / m 2 ) as the thermoplastic resin fiber nonwoven fabric a, except that the same method as in Example 1 was used to obtain a material having a unit area mass of 75 g / m 2 Heat seal film.

[0173] In Example 7, a polyester wet nonwoven fabric (fiber diameter of about 14 μm, fiber length of about 5 mm, mass per unit area of ​​20 g / m 2) as the thermoplastic resin fiber nonwoven fabric a, except that the same method as in Example 1 was used to obtain a material having a unit area mass of 90 g / m 2 Heat seal film.

[0174] [Example 8]

[0175] <Manufacturing of thermoplastic resin fiber nonwoven fabric c>

[0176] 60 parts by mass of polyethylene multi-branched fibers (trade name: SWP (registered trademark) E400, melting point 135°C, average fiber length 0.9 mm, fiber diameter about 1 to 30 μm, manufactured by Mitsui Chemicals, Inc.), 10 parts by mass of core-sheath structured polyester fibers (trade name: Tepyrus (registered trademark) TJ04CN, fineness 1.1 dtex, fiber length 5 mm, fiber diameter about 10 μm, sheath melting point 110°C, core (polyethylene terephthalate) melting point 260°C, sheath / core mass ratio = 55 / 45, manufactured by TEIJINFRONTIER CO., LTD.), and hardwood bleached kraft pulp (LBKP) (JIS P 8121-2:2012) and 0.5 parts by mass of a modified polyester resin dispersant (trade name: SR-1800R, manufactured by Takamatsu Oil & Fats Co., Ltd.) were mixed and stirred to obtain a raw material slurry.

[0177] The raw material slurry was made into paper using a wet inclined paper machine and dried in a Yankee dryer at a surface temperature of 105°C to obtain a paper with a unit area weight of 30 g / m 2 Thermoplastic resin fiber nonwoven fabric c.

[0178] <Manufacturing of heat sealing sheets>

[0179] The three layers of thermoplastic resin fiber nonwoven fabric b, thermoplastic resin fiber nonwoven fabric a, and thermoplastic resin fiber nonwoven fabric c obtained in the same manner as in Example 1 were stacked in order and subjected to heat lamination treatment in a heat laminating machine having a heating roller coated with fluorine on the surface, with the roller temperature of the upper and lower rollers set to 150° C., to obtain a nonwoven fabric having a mass per unit area of ​​75 g / m 2 The heat sealing sheet of Example 8.

[0180] Wet polyester nonwoven fabric (fiber diameter about 14 μm, fiber length about 5 mm, unit area mass 20 g / m 2 ) as thermoplastic resin fiber nonwoven fabric a.

[0181] [Comparative Example 4]

[0182] <Manufacturing of paper substrate>

[0183] Bleached kraft pulp (LBKP) was beaten in a DDR (double disc refiner) to a Canadian standard freeness of 390 mL as described in JIS P 8121-2: 2012 to obtain a pulp slurry. To the pulp slurry, as internal additives, 0.5 parts by mass of aluminum sulfate on an absolute dry basis, 0.05 parts by mass of an alkenyl succinic anhydride sizing agent dispersion in which the alkenyl succinic anhydride sizing agent was preliminarily dispersed in cationized starch, 0.7 parts by mass of an amphoteric polyacrylamide resin paper strength agent (PAM) (trade name: POLYSTRON OFT-3, manufactured by Arakawa Chemical Industries, Ltd., weight average molecular weight 3,000,000), and 0.4 parts by mass of an epichlorohydrin resin wet paper strength agent (trade name: WS4024, manufactured by Seiko PMC Co., Ltd.) were added to obtain a papermaking raw material. The papermaking raw material was used to make paper in a Fourdrinier papermaking machine to obtain an air-permeable substrate. The mass per unit area of ​​the obtained air-permeable substrate was 60 g / m 2 .

[0184] It should be noted that the aforementioned "dispersion of alkenyl succinic anhydride sizing agent pre-dispersed in cationized starch" is prepared as follows. A 2 mass % aqueous solution of cationized starch (Pillar 3YK, manufactured by Pillar Corporation) is prepared, and alkenyl succinic anhydride sizing agent is added thereto in a solid content concentration of 4 / 1 of cationized starch (Pillar 3YK, manufactured by Pillar Corporation) / alkenyl succinic anhydride sizing agent (Fibran 81K, manufactured by Arakawa Chemical Industries, Ltd.). 0.05 mass parts of the aqueous solution prepared as above is added in terms of the solid content of alkenyl succinic anhydride.

[0185] <Preparation of coating material for thermal adhesive layer>

[0186] 138 parts of EVA dispersion (Chemipearl V200, manufactured by Mitsui Chemicals, Inc., average particle size of EVA particles 7 μm, minimum film forming temperature 85°C, solid content concentration 40%), PE dispersion (Chemipearl W400, manufactured by Mitsui Chemicals, Inc., average particle size of PE particles 4 μm, solid content concentration 40%, PE density 920 kg / m 3 , softening point 110°C), 90 parts of a reinforced rosin emulsion (SIZEPINE N775, manufactured by Arakawa Chemical Industries, Ltd., with a softening point below 100°C and a solid content concentration of 50%), and 154 parts of dilution water were mixed and stirred to obtain a coating for a thermal adhesive layer with a solid content concentration of 25%.

[0187] <Manufacturing of heat sealing sheets>

[0188] The above-mentioned heat-adhesive layer coating material was applied to one side of the air-permeable substrate obtained above using a bar coater, and dried in a blower dryer at 100° C. for 1 minute to form a heat-adhesive layer. Here, the coating amount of the heat-adhesive layer coating material after drying was 2.0 g / m 2 Thus, the heat-sealing sheet of Comparative Example 4 was obtained.

[0189] [Measurement method]

[0190] The heat sealing sheets and nonwoven fabrics obtained in Examples and Comparative Examples were evaluated as follows.

[0191] <Mass per unit area>

[0192] The mass per unit area is measured in accordance with JIS P 8124:2011.

[0193] <Determination of Wang Yan's air permeability>

[0194] The Ogan-type air permeability of the heat-sealed sheet is measured in accordance with JIS P 8117:2009.

[0195] When the air permeability is 700 seconds or less, ethylene oxide gas sterilization can be applied, which is preferred. When the air permeability exceeds 700 seconds, the permeation rate of ethylene oxide gas decreases, and the sterilization efficiency decreases, which is not preferred.

[0196] <Measurement of tear strength>

[0197] The tear strength of the heat-sealed sheet was calculated by measuring the longitudinal and transverse directions of the sheet in accordance with JIS P 8116:2000 and calculating the geometric mean of these values.

[0198] When the tear strength is 700 mN or more, it is preferred that the sterilized medical packaging material can be used for relatively large medical instruments and medical devices with large mass. When the tear strength is less than 700 mN, when packaging relatively large medical instruments and medical devices with large mass, there is a concern that the sterilized medical packaging material may be broken during transportation or when accidentally dropped, and the sterilization state inside the package may not be maintained.

[0199] <Measurement of heat seal peel strength (HS peel strength)>

[0200] The heat sealing sheets obtained in the embodiments and comparative examples and a laminated film of polyethylene terephthalate resin (PET) and PE as an adherend (a laminated film formed by dry laminating a 50 μm thick polyethylene film and a 12 μm thick PET film) were overlapped in a manner such that the surface on the heat adhesive layer side (thermoadhesive surface) of the heat sealing sheet was in contact with the surface on the PE side of the laminated film, and heat-compression-bonded them using a heat press testing machine under the heat-compression bonding conditions of 150° C., 0.2 MPa, and 1.0 second to produce a heat-compression-bonded product.

[0201] The heat-pressed product prepared by the above method was cut into 15 mm width to prepare a sample for peel strength measurement. The peel strength (N / 15 mm) of the obtained sample for peel strength measurement was measured according to JIS P 8113:2006 by clamping the ends of the composite film and heat-sealing sheet of the sample with a tensile tester (model: TENSILON RTC-1250A, manufactured by Orientec Co., Ltd.) and peeling by 180 degree peeling method at a peeling speed of 300 mm / min.

[0202] <Evaluation of fluff after peeling>

[0203] The heat-sealing sheet cut into 25mm×100mm and the laminated film of (PET) and PE (laminated film formed by dry laminating a 50μm thick polyethylene film and a 12μm PET film) are overlapped in such a way that the PE side of the laminated film contacts the heat-sealing sheet and the film is on the top, and heat-pressed under the conditions of 150°C, 0.2MPa, and 1.0 seconds using a hot press tester to produce a heat-pressed product. The film of the heat-pressed product produced by the above method is peeled off by hand, and the state of the heat-sealing sheet surface after the film is peeled off is visually confirmed, and the evaluation is performed using the following criteria. If there is less fuzzing after peeling, it means that the occurrence of lint is suppressed.

[0204] 5: No fluff at all

[0205] 4: There are a few hairs

[0206] 3: Less fluff

[0207] 2: Lots of fluff

[0208] 1: There is a lot of fluff or the substrate is damaged

[0209] <Interlayer adhesion of heat seal sheets>

[0210] The state of the heat-sealed sheet after lamination by thermocompression bonding was evaluated based on the following criteria.

[0211] 5: Firmly attached, not peeled off

[0212] 4: Firmly adhered, but partially peeled off

[0213] 3: The whole piece is bonded, but it is easy to peel off

[0214] 2: Part of the sheet is not bonded and has floating areas

[0215] 1: Basically no adhesion

[0216] The heat seal sheets of Examples 1 to 8 and Comparative Examples 1 to 4 were evaluated for Okanagan air permeability, tear strength, peel test, fuzz after peeling, and adhesion between the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B. The results are shown in Table 1.

[0217] [Table 1]

[0218]

[0219] The air permeability (seconds) of the heat-sealing sheets of Examples 1 to 8 is suppressed to a relatively low level, and it is believed that they can be used for ethylene oxide gas sterilization. In addition, the tear strength is also sufficiently strong, and it is believed that they can also be used for sterilization of large medical devices and medical devices of a certain quality. Furthermore, the heat sealing strength is also sufficiently obtained. Furthermore, the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B are well bonded, the interlayer adhesion is also excellent, and the generation of lint is also suppressed.

[0220] On the other hand, when the content of the polyethylene resin in the thermoplastic resin fiber nonwoven fabric layer B exceeds the limit of the present invention, as in Comparative Examples 1 and 2, the air permeability exceeds 700 seconds, and it is not suitable for sterilization with ethylene oxide. In addition, when the content of the low melting point polyester resin and the polyester fiber in the thermoplastic resin fiber nonwoven fabric layer B exceeds the limit of the present invention, as in Comparative Example 3, sufficient heat seal peel strength cannot be obtained, and the adhesion between the layers is also poor. Furthermore, when a thermal adhesive layer is provided on the paper substrate, as in Comparative Example 4, sufficient tear strength cannot be obtained.

[0221] Industrial Applicability

[0222] The heat-sealing sheet of the present invention has sufficient thermal adhesiveness and air permeability throughout the heat-sealing surface, is high in strength, and suppresses the amount of lint generated to a small level, and is excellent as a sterilized medical packaging material.

[0223] Description of Reference Numerals

[0224] 11 ... sterilization packaging body, 21 ... heat sealing sheet, 22 ... thermoplastic resin fiber nonwoven fabric layer A, 23 ... thermoplastic resin fiber nonwoven fabric layer B, 31 ... adherend, 41 ... thermoplastic resin fiber nonwoven fabric layer C

Claims

1. A heat sealing sheet comprising: one or more layers of thermoplastic resin fiber nonwoven fabric layer A, and one or more layers of thermoplastic resin fiber nonwoven fabric layer B, The thermoplastic resin fiber nonwoven fabric layer B contains a low melting point polyester resin, polyester fiber and polyethylene resin, and the mass ratio of the low melting point polyester resin, polyester fiber and polyethylene resin (low melting point polyester resin: polyester fiber: polyethylene resin) is 13.75:11.25:75-41.25:33.75:

25. The heat seal sheet has a Wangyan air permeability of 700 seconds or less as measured in accordance with JIS P 8117:2009, and The heat sealing sheet has a tear strength of 700 mN or more as measured in accordance with JIS P 8116:2000.

2. The heat sealing sheet according to claim 1, wherein: The thermoplastic resin fiber nonwoven fabric layer A is a nonwoven fabric layer derived from at least one selected from the group consisting of spunbonded nonwoven fabric, thermally bonded nonwoven fabric, chemically bonded nonwoven fabric, needle-punched nonwoven fabric, spunlace nonwoven fabric, meltblown nonwoven fabric and wet-laid nonwoven fabric.

3. The heat sealing sheet according to claim 1, wherein: The thermoplastic resin fiber nonwoven fabric layer A includes at least one selected from the group consisting of polypropylene resin fibers, polyester fibers, and polyamide fibers.

4. The heat sealing sheet according to claim 1, wherein: The thermoplastic resin fiber nonwoven fabric layer A has fiber shapes remaining therein.

5. The heat sealing sheet according to claim 1, wherein: The heat sealing sheet and a sterilization packaging material such as paper, film or sterilization molded container have a peel strength of 1.0 N / 15 mm or more and 15 N / 15 mm or less when peeled 180 degrees at a peeling speed of 300 mm / min in accordance with JIS P 8113:2006.

6. The heat sealing sheet according to claim 1, having a mass per unit area of ​​30 g / m 2 Above and 150g / m 2 the following. 7 . The heat sealing sheet according to claim 1 , wherein the thermoplastic resin fiber nonwoven fabric layer A and the thermoplastic resin fiber nonwoven fabric layer B are laminated so that the thermoplastic resin fiber nonwoven fabric layer B becomes a surface layer.

8. A sterilization packaging body, comprising the heat sealing sheet according to any one of claims 1 to 7 and a sterilization packaging material bonded by thermal compression.

9. A method for producing a heat-sealing sheet, which is the method for producing a heat-sealing sheet according to any one of claims 1 to 7, the method comprising the following steps 1 to 3 in sequence: Step 1: a step of preparing thermoplastic resin fiber nonwoven fabric a and thermoplastic resin fiber nonwoven fabric b; Step 2: a step of laminating one or more layers of thermoplastic resin fiber nonwoven fabric a and one or more layers of thermoplastic resin fiber nonwoven fabric b to obtain a laminate; Step 3: A step of heat-sealing the laminated body obtained in step 2.

10. The method for manufacturing a heat sealing sheet according to claim 9, wherein: The thermoplastic resin fiber nonwoven fabric b contains 25 to 75% by mass of polyethylene multi-branched fibers.

11. The method for manufacturing a heat sealing sheet according to claim 9, wherein: The thermoplastic resin fiber nonwoven fabric b contains core-sheath structure polyester fibers.

12. The method for manufacturing a heat sealing sheet according to claim 9, wherein: The thermoplastic resin fiber nonwoven fabric b is a nonwoven fabric obtained by a wet papermaking method.

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