阅读说明：本技术 灭菌用包装材料用无纺布 (Nonwoven fabric for packaging material for sterilization ) 是由 日下部纯一 佐佐木悠介 森将彰 小松隆志 于 2020-03-19 设计创作，主要内容包括：提供在作为灭菌包装材料能够设想的各种环境之中都不会破袋、可以应付所有的灭菌处理方法、可以保持内部的无菌状态的灭菌用包装材料用无纺布,以及可以兼顾不会破袋、而能够容易处理的易剥离性、和将包装材料内保持于无菌状态的阻挡性的灭菌用包装材料用无纺布。本发明的灭菌用包装材料用无纺布的特征在于,作为表层热封面,具有孔隙率为30％以上且60％以下的纤维层(I),作为阻障层,具有纤维的比表面积为1.0m～(2)/g以上且10m～(2)/g以下、且每1mg中相当于1cm的丝根数为800根以上且1000000根以下的纤维层(II),并且纤维层(I)与纤维层(II)层叠,以及本发明的灭菌用包装材料用无纺布的特征在于,重均纤维直径为3μm以上且30μm以下、并且质地系数为1.0以上且5.0以下。(Provided are a nonwoven fabric for a packaging material for sterilization which can cope with all sterilization methods and can maintain the inside sterile state without breaking a bag in various environments which can be assumed as a packaging material for sterilization, and a nonwoven fabric for a packaging material for sterilization which can satisfy both easy peelability which enables easy handling without breaking a bag and barrier property which can maintain the inside of a packaging material in a sterile stateAnd (3) cloth. The nonwoven fabric for a packaging material for sterilization of the present invention is characterized by having a fiber layer (I) having a porosity of 30% or more and 60% or less as a surface layer heat-seal surface, and a barrier layer having a specific surface area of fibers of 1.0m 2 More than 10 m/g 2 A fiber layer (II) having 800 to 1000000 filaments per 1mg and a fiber layer (I) laminated with the fiber layer (II), wherein the weight-average fiber diameter is 3 to 30 [ mu ] m, and the texture index is 1.0 to 5.0.)

1. A nonwoven fabric for a packaging material for sterilization, characterized by comprising a fiber layer (I) having a porosity of 30% or more and 60% or less as a surface layer heat-seal surface, and a barrier layer having a specific surface area of fibers of 1.0m²More than 10 m/g²A fiber layer (II) having 800 to 1000000 filaments per 1mg and a number of filaments per 1cm of not more than g, wherein the fiber layer (I) and the fiber layer (II) are laminated.

2. The nonwoven fabric for a packaging material for sterilization according to claim 1, wherein the heat seal strength of the fiber layer (I) is 5N/25mm or more and 25N/25mm or less.

3. The nonwoven fabric for packaging material for sterilization according to claim 1 or 2, wherein the fibers constituting the fiber layer (II) are polypropylene fibers.

4. The nonwoven fabric for packaging materials for sterilization according to any one of claims 1 to 3, wherein the fiber diameter of the fibers constituting the fiber layer (I) is 5 μm or more and 30 μm or less, and the fiber diameter of the fibers constituting the fiber layer (II) is 0.05 μm or more and 5 μm or less.

5. The nonwoven fabric for packaging materials for sterilization according to any one of claims 1 to 4, wherein the fiber diameter of the fibers constituting the fiber layer (I) is 5 μm or more and 20 μm or less.

6. The nonwoven fabric for packaging material for sterilization according to any one of claims 1 to 5, comprising at least one of the fiber layers (I) and at least two of the fiber layers (II).

7. A nonwoven fabric for a packaging material for sterilization, characterized in that the weight-average fiber diameter is 3 to 30 μm, and the texture coefficient is 1.0 to 5.0.

8. The nonwoven fabric for packaging material for sterilization according to claim 7, which is composed of long fibers.

9. The nonwoven fabric for packaging material for sterilization according to claim 7 or 8, which has a puncture strength of 50N or more and 500N or less.

10. The nonwoven fabric for a packaging material for sterilization according to any one of claims 7 to 9, which has a tear strength of 0.5N or more and 20N or less in both the MD direction and the CD direction.

11. The nonwoven fabric for a packaging material for sterilization according to any one of claims 7 to 10, which has a tensile strength of 30N/25m or more and 300N/25mm or less in both the MD direction and the CD direction, and a ratio of the tensile strength in the MD direction to the tensile strength in the CD direction of 1.2 or more and 5.0 or less.

12. The nonwoven fabric for a packaging material for sterilization according to any one of claims 7 to 11, wherein the nonwoven fabric for a packaging material for sterilization has a fiber layer (A) composed of continuous long fibers having an average fiber diameter of 5 μm or more and 30 μm or less as a surface layer heat-seal surface, and has a fiber layer (B) composed of ultrafine fibers having an average fiber diameter of 0.1 μm or more and 4 μm or less as a barrier layer, and the fiber layer (A) and the fiber layer (B) are laminated.

13. The nonwoven fabric for packaging use according to claim 12, wherein the fiber layer (B) is present as an intermediate layer between the 2 fiber layers (a).

14. The nonwoven fabric for a packaging material for sterilization according to claim 12 or 13, wherein the fiber layer (B) is formed of a meltblown nonwoven fabric.

15. The nonwoven fabric for packaging material for sterilization according to any one of claims 7 to 14, which is composed of polyester fibers.

16. The nonwoven fabric for packaging material for sterilization according to any one of claims 7 to 15, which has a water pressure resistance of 10cmH₂O or more.

17. The nonwoven fabric for a packaging material for sterilization according to any one of claims 7 to 16, having an average flow pore size of 0.5 μm or more and 20 μm or less.

18. The nonwoven fabric for a packaging material for sterilization according to any one of claims 7 to 17, having an atmospheric dust collection efficiency of 90% or more.

19. The nonwoven fabric for packaging material for sterilization according to any one of claims 1 to 18, having a total weight per unit area of 20g/m²Above and 100g/m²The following.

20. The nonwoven fabric for a packaging material for sterilization according to any one of claims 1 to 19, having a permeability of 0.1 sec/100 mL or more and 100 sec/100 mL or less as measured by the gurley-type permeability test.

21. The nonwoven fabric for a packaging material for sterilization according to any one of claims 1 to 20, having an air permeability of 0.1 sec/100 mL or more and 20 sec/100 mL or less as measured by the gurley-type air permeability test.

22. The nonwoven fabric for packaging material for sterilization according to any one of claims 1 to 21, having a total thickness of 50 μm or more and 300 μm or less.

23. The nonwoven fabric for packaging material for sterilization according to any one of claims 1 to 22, having a surface coverage of 40% or more and 99% or less.

Technical Field

The present invention relates to a nonwoven fabric for a packaging material for sterilization used for sterilization of medical instruments.

Background

As medical instruments, it is known to use instruments subjected to sterilization treatment for preventing infection, and specific examples thereof include scalpels (mes), tweezers (pincettes), scissors, and the like. As a method of sterilization treatment, a high-temperature high-pressure steam method, an ethylene oxide gas method, or the like is used, and a packaging material for sterilization suitable for these methods is used. The packaging material for sterilization is required to have good air permeability for sterilization treatment, high barrier properties for maintaining sterility, and easy peelability for peeling with appropriate strength at the time of opening. Particularly, the easy peelability is important because, if the strength at the time of peeling is high, there is a possibility that the packaging material is broken and contamination of the medical instrument due to generation of paper powder and silk waste is caused.

Further, with the recent advanced development of medical technology, the medical environment is steadily improved in various countries in the world, and the performance required for the packaging material is also advanced to the past or more, and the strength is given in many cases. Many medical instruments are sharp, and there are large and heavy instruments depending on the articles. As a packaging material for these, it is required that the bag is not broken until just before use, and nonwoven fabric strength such as tear strength and puncture strength is required.

Generally, as the packaging material for sterilization, nonwoven fabrics and films made of synthetic fiber resins typified by pulp-based resins and polyethylene resins are used, and in recent years, a packaging material for sterilization in which nonwoven fabrics and transparent resin films are combined and bonded to form a bag-like body has been used in order to make the inside visible.

For example, patent document 1 below reports a nonwoven fabric produced by a flash spinning method using a polyethylene resin as a fibrous sheet used in the medical field. In the case of flash spinning, the yarn diameter is not uniform, the production cannot be carried out in a region having an average fiber diameter of 2 μm or less, the dispersibility per unit area weight of the obtained nonwoven fabric is not good, and a solvent is required, and therefore, the method is not practical from the viewpoint of safety.

Further, patent document 2 below reports pulp-based sterilized paper, and describes that heat sealability is obtained by laminating sterilized paper and a synthetic resin film. However, when pulp-based sterilization paper is used as a packaging material for sterilization, 1 fiber is discontinuous in 1 fiber as compared with a long fiber nonwoven fabric, and paper powder is scattered during processing, which is a fatal problem as a medical instrument. In addition, in an environment where alcohol, water, or the like is frequently used, the pulp-based sterilized paper is very brittle and is not acceptable as a packaging material.

Patent document 3 below reports a laminated nonwoven fabric using a meltblown nonwoven fabric, and describes that heat sealability is obtained by forming the nonwoven fabric from a thermoplastic resin. As one of the methods for obtaining a good peelability, bonding of fibers by calendering is exemplified. However, there is no mention of the compatibility between the heat seal strength (peel strength) and the barrier property.

As for the strength, for example, patent document 4 below describes an example in which the strength is improved by using a characteristic material for a sterilized paper that is generally used. It has been reported that a base paper containing softwood pulp (N material) and hardwood pulp (L material) in a mass ratio of 5/5 to 7/3 and having a beating degree of 25 ° SR to 40 in terms of Schopper freeness (Schopper freeness) is impregnated with a resin, and a heat sealing agent layer is formed on one surface of the base paper, whereby a sterilized paper having a puncture strength after sterilization treatment while maintaining high gas permeability can be obtained.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-237478

Patent document 2: japanese laid-open patent publication No. 7-238449

Patent document 3: international publication No. 2017/146050

Patent document 4: japanese laid-open patent publication No. 2004-29304

Disclosure of Invention

Problems to be solved by the invention

In view of the above-described problems of the prior art, an object of the present invention is to provide a nonwoven fabric for a packaging material for sterilization that can achieve both easy peelability that enables easy handling without breaking a bag and barrier properties that maintain the inside of the packaging material in a sterile state, and to provide a nonwoven fabric for a packaging material for sterilization that can cope with all sterilization methods without breaking a bag in various environments that can be assumed as a packaging material for sterilization, and that can maintain the inside sterile state.

Means for solving the problems

The present inventors have intensively studied and repeated experiments to solve the above problems, and as a result, they have found that both easy peelability and barrier properties can be achieved by reducing the porosity of a surface layer that contributes to easy peelability of a nonwoven fabric and increasing the number of filaments of a layer that contributes to barrier properties, and that a nonwoven fabric having a specific fiber structure and a texture index within a specific range and having high strength can be obtained, thereby completing the present invention.

Namely, the present invention is as follows.

[1]A nonwoven fabric for a packaging material for sterilization, characterized by comprising a fiber layer (I) having a porosity of 30% or more and 60% or less as a surface layer heat-seal surface, and a barrier layer having a specific surface area of fibers of 1.0m²More than 10 m/g²A fiber layer (II) having 800 to 1000000 filaments per 1mg and a number of filaments per 1cm of not more than g, wherein the fiber layer (I) and the fiber layer (II) are laminated.

[2] The nonwoven fabric for a packaging material for sterilization according to the above [1], wherein the heat seal strength of the fiber layer (I) is 5N/25mm or more and 25N/25mm or less.

[3] The nonwoven fabric for a packaging material for sterilization according to the above [1] or [2], wherein the fiber constituting the fiber layer (II) is a polypropylene fiber.

[4] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [3], wherein the fiber diameter of the fibers constituting the fiber layer (I) is 5 μm or more and 30 μm or less, and the fiber diameter of the fibers constituting the fiber layer (II) is 0.05 μm or more and 5 μm or less.

[5] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [4], wherein the fiber diameter of the fibers constituting the fiber layer (I) is 5 μm or more and 20 μm or less.

[6] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [5], which comprises at least one fiber layer (I) and at least two fiber layers (II).

[7] A nonwoven fabric for a packaging material for sterilization, characterized in that the weight-average fiber diameter is 3 to 30 μm, and the texture coefficient is 1.0 to 5.0.

[8] The nonwoven fabric for a packaging material for sterilization according to the above [7], which is composed of long fibers.

[9] The nonwoven fabric for packaging material for sterilization according to the above [7] or [8], which has a puncture strength of 50N to 500N.

[10] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [9], which has a tear strength of 0.5N or more and 20N or less in both the MD direction and the CD direction.

[11] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [10], which has a tensile strength of 30N/25mm or more and 300N/25mm or less in both the MD direction and the CD direction, and a ratio of the tensile strength in the MD direction/the tensile strength in the CD direction of 1.2 or more and 5.0 or less.

[12] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [11], wherein the nonwoven fabric for a packaging material for sterilization has a fiber layer (A) composed of continuous long fibers having an average fiber diameter of 5 μm or more and 30 μm or less as a surface layer heat-seal surface, and has a fiber layer (B) composed of ultrafine fibers having an average fiber diameter of 0.1 μm or more and 4 μm or less as a barrier layer, and the fiber layer (A) and the fiber layer (B) are laminated.

[13] The nonwoven fabric for a packaging material for sterilization according to the above [12], wherein the fiber layer (B) is present as an intermediate layer between 2 of the fiber layers (A).

[14] The nonwoven fabric for a packaging material for sterilization according to any one of the above [12] or [13], wherein the fiber layer (B) is formed of a meltblown nonwoven fabric.

[15] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [14], which is composed of a polyester fiber.

[16]According to the above [7]]～[15]The nonwoven fabric for packaging material for sterilization, which has a water pressure resistance of 10cmH₂O or more.

[17] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [16], which has a mean flow pore size of 0.5 μm or more and 20 μm or less.

[18] The nonwoven fabric for a packaging material for sterilization according to any one of the above [7] to [17], which has an atmospheric dust collection efficiency of 90% or more.

[19]According to the above [1]]～[18]The nonwoven fabric for packaging material for sterilization as described in any one of the above, which has a total weight per unit area of 20g/m²Above and 100g/m²The following.

[20] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [19], having an air permeability of 0.1 sec/100 mL or more and 100 sec/100 mL or less as measured by a Gurley air permeability test.

[21] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [20], having an air permeability of 0.1 sec/100 mL or more and 20 sec/100 mL or less as measured by a Gurley air permeability test.

[22] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [21], which has a total thickness of 50 μm or more and 300 μm or less.

[23] The nonwoven fabric for a packaging material for sterilization according to any one of the above [1] to [22], which has a surface coverage of 40% or more and 99% or less.

ADVANTAGEOUS EFFECTS OF INVENTION

In the first aspect of the present invention, a nonwoven fabric for a packaging material for sterilization can be provided which has both easy peelability and barrier properties by laminating a fiber layer having a low porosity and a fiber layer having a high specific surface area and a large number of filaments. In the second aspect of the present invention, since the fiber structure is specified and the strength is high, it is possible to cope with all sterilization methods and maintain the sterile state of the inside of the packaging material at a high level.

Detailed Description

The embodiments of the present invention will be described in detail below.

The nonwoven fabric for a packaging material for sterilization according to the first embodiment of the present invention is characterized by having a fiber layer (I) having a porosity of 30% or more and 60% or less as a surface layer heat-seal surface, and a fiber specific surface area of 1.0m as a barrier layer²More than 10 m/g²A fiber layer (II) having 800 or more filaments per 1mg and a number of filaments per 1cm, wherein the fiber layer (I) and the fiber layer (II) are laminated.

In the present specification, the term "fiber layer" refers to a layer composed of fibers having substantially the same fiber diameter, and the term "nonwoven fabric" refers to a fabric having 1 fiber layer or a fabric having at least 2 fiber layers laminated and combined.

In the nonwoven fabric for a packaging material for sterilization according to the first embodiment of the present invention, it is important to reduce the porosity of the fiber layer (I) of the surface layer subjected to heat sealing, and the porosity is 30% or more and 60% or less, preferably 45% or more and 55% or less, and more preferably 40% or more and 50% or less. The porosity is 60% or less, whereby the gaps between the filaments can be reduced, and the penetration of a welding component such as a film at the time of heat sealing can be suppressed by being blocked by the surface layer, whereby easy peelability with appropriate strength can be ensured. The index of easy peelability includes peel strength in peeling a film or the like, and is preferably lower from the viewpoint of easy peelability, and when the peel strength is 27cN/25mm or less, peeling can be easily performed by manpower, and it can be said that the peeling property is easy, and is more preferably 25cN/25mm or less. Further, the porosity of 30% or more ensures air permeability of the nonwoven fabric, and the nonwoven fabric can be effectively sterilized inside during sterilization treatment.

The fiber layer (II) of the nonwoven fabric for packaging material for sterilization in the first embodiment of the present invention has a specific surface area of 1.0m for the fibers to exhibit high barrier properties²More than 10 m/g²A ratio of 1.2m or less per gram²More than g and 8m²A ratio of 1.5m or less per gram²More than 5 m/g²The ratio of the carbon atoms to the carbon atoms is less than g. If the specific surface area is 1.0m²The amount of the bacteria is sufficiently large at the filament surface for trapping bacteria. On the other hand, if the specific surface area is 10m²The gas permeability can be maintained at a level of not more than g, and high sterilization efficiency can be secured.

The fiber layer (II) of the nonwoven fabric for a packaging material for sterilization in the first embodiment of the present invention has a number of filaments per 1mg corresponding to 1cm of 800 or more and 1000000 or less, preferably 1000 or more and 800000 or less, and more preferably 10000 or more and 500000 or less. When the number of the bacteria is 800 or more, the contact frequency between the bacteria and the filaments increases, and the collection efficiency improves. On the other hand, 1000000 or less exhibits a certain or more air permeability, and both the trapping efficiency and the air permeability can be satisfied.

The fiber layer (I) of the nonwoven fabric for a packaging material for sterilization in the first embodiment of the present invention is disposed as a heat-seal surface on the surface layer, and has a heat-seal strength of 5N/25mm or more and 25N/25mm or less, preferably 8N/25mm or more and 23N/25mm or less, and more preferably 10N/25mm or more and 20N/25mm or less. When the heat seal strength is 5N/25mm or more, accidental bag breakage during handling can be prevented, and the reliability of the aseptic state can be ensured. On the other hand, if the thickness is 25N/25mm or less, the opening can be performed without generating silk waste or paper powder, and contamination of the medical instrument can be avoided.

The fibers constituting the fiber layer (II) of the nonwoven fabric for a packaging material for sterilization in the first embodiment of the present invention are preferably polypropylene fibers. Since polypropylene is a resin having low density while having heat resistance to steam sterilization, the number of filaments corresponding to 1cm per 1mg is increased, and high barrier properties are likely to be exhibited. Further, polypropylene has high heat resistance among low-density resins, and therefore, even in a sterilization method in which heat is applied such as steam sterilization, sterilization treatment can be performed without heat shrinkage. Therefore, polypropylene that can achieve both low density and heat resistance is a preferred material.

The nonwoven fabrics for packaging material for sterilization in the first and second embodiments of the present invention had a total basis weight of 20g/m²Above and 100g/m²Below, preferably 30g/m²Above 90g/m²Below, more preferably 40g/m²Above and 80g/m²The following. If the total weight per unit area is 20g/m²The above constitution can provide sufficient strength and prevent bag breakage during handling. On the other hand, if it is 100g/m²Sufficient air permeability required for sterilization treatment can be obtained as follows.

The nonwoven fabrics for sterilization wrap according to the first and second embodiments of the present invention preferably have an air permeability of 0.1 sec/100 mL or more and 100 sec/100 mL or less when 100mL of air passes through the laminated nonwoven fabric in the gurley type air permeability test. When the average flow pore diameter is 0.1 sec/100 mL or more, a small average flow pore diameter can be obtained, and the bacteria-blocking property can be secured, and the composition can be used as a sterilized packaging material. On the other hand, if it is 100 seconds/100 mL or less, the permeability of gas and vapor can be secured, and the sterilization treatment of the internal medical instrument can be performed. From this viewpoint, the air permeability is more preferably 0.2 sec/100 mL or more and 80 sec/100 mL or less, and still more preferably 0.5 sec/100 mL or more and 20 sec/100 mL or less.

The fiber diameter of the fibers constituting the fiber layer (I) of the nonwoven fabric for packaging material for sterilization in the first embodiment of the present invention is preferably 5 μm or more and 20 μm or less, more preferably 8 μm or more and 18 μm or less, and still more preferably 10 μm or more and 15 μm or less. When the average diameter is 5 μm or more, sufficient monofilament strength can be obtained. On the other hand, when the thickness is 20 μm or less, the voids in the surface layer are reduced, and the penetration of a welding component such as a film is suppressed, whereby easy peeling can be achieved.

The total thickness of the nonwoven fabrics for sterilization wrap according to the first and second embodiments of the present invention is preferably 50 μm or more and 500 μm or less, more preferably 70 μm or more and 400 μm or less, and still more preferably 100 μm or more and 300 μm or less. When the total thickness is 50 μm or more, sufficient mechanical strength of the nonwoven fabric can be obtained. On the other hand, if the thickness is 500 μm or less, the air permeability of the nonwoven fabric can be prevented from being impaired.

The method for producing each fiber layer is not limited, but the method for producing the fiber layer (I) is preferably a spunbond method, a dry method, a wet method, or the like, and a spunbond method is more preferable from the viewpoint of good productivity. The fiber layer (II) can be preferably produced by a dry method, a wet method or the like using ultrafine fibers, an electrospinning method, a melt blowing method or the like. The melt blowing method is more preferable because the ultrafine nonwoven fabric can be easily and densely formed.

As a method for laminating and integrating the fiber layer (I) and the fiber layer (II), thermal bonding is preferably used. Examples of a bonding method using heat of thermal bonding include calendering and integration using hot air at a high temperature (hot air method). In particular, hot calendering is preferable in order to form the fiber layer (I) into a low porosity while maintaining the fiber layer (II) in a high porosity.

The nonwoven fabric for a packaging material for sterilization of the present embodiment can satisfy both of the easy peelability and the barrier property by laminating the fiber layer (I) having a low porosity and the fiber layer (II) having a large number of filaments corresponding to 1cm per 1 mg.

When a method using thermal bonding is used as a method for laminating and integrating the fiber layer (I) and the fiber layer (II), a dense surface structure in which fibers are strongly bonded to each other with few voids is required in order to exhibit easy peelability of the fiber layer (I), and processing under high temperature and/or high pressure is preferable. On the other hand, in order to exhibit high blocking properties of the fiber layer (II), it is preferable to prevent fusion between filaments while maintaining the fiber structure inside the nonwoven fabric, to increase the filament surface area, and to perform processing under low temperature and/or low pressure conditions. Therefore, in order to satisfy both of the easy peelability and the barrier property, it is preferable to control the temperature, pressure, and heating time, rather than the usual thermal joining process. For example, in the case of hot calendering, by using a low-hardness roller, the fiber layer (I) can be uniformly and sufficiently crimped while the energy applied to the crimping of the fiber layer (II) is reduced. Preferably, the hardness of the roller is 50 to 90 in terms of type A durometer, and the pressure is 5kg/cm or more and 30kg/cm or less in terms of linear pressure. The type A durometer hardness refers to a value measured by JIS K2653-3. This makes it possible to achieve both easy peelability and barrier properties by providing the fiber layer (I) with a uniform, dense structure with few voids, and the fiber layer (II) with a structure in which structural failure due to hot calendering is sufficiently reduced and no fusion between filaments is formed.

The nonwoven fabric for a packaging material for sterilization in accordance with the second embodiment of the present invention is characterized in that the weight-average fiber diameter is 3 μm or more and 30 μm or less, and the texture coefficient is 1.0 or more and 5.0 or less.

The weight-average fiber diameter is a parameter indicating the network structure of the fibers existing inside the nonwoven material. Specifically, from the viewpoint of the average fiber diameter, the network structure of the fibers when viewed as the whole nonwoven fabric is shown.

The smaller the weight-average fiber diameter, the more the interlacing points between the fibers increase, and the number of bonding points between the fibers increases. In addition, the base fabric strength (tensile strength, puncture strength, tear strength) of the nonwoven fabric material is dominated by the number of fiber bonding points (number of intertwining points) in the network structure and the strength of one bonding point, and the larger the number of bonding points between fibers, the more the continuous fiber structure is reinforced and less likely to break. From this viewpoint, if the weight-average fiber diameter is 30 μm or less, the number of fiber-entangled points increases, and the nonwoven fabric has a large number of fibers entangled thereinThe structure of the portion can form a high-level network structure, and the strength of the base fabric as a nonwoven fabric, which is expressed by the adhesive force of each interlaced point, is increased, and the portion can be used as a packaging material for sterilization without breaking a bag even for sharp medical instruments such as scalpels and scissors. On the other hand, if the weight-average fiber diameter is 3 μm or more, the minimum air permeability can be maintained, the vapor and gas permeability is excellent, and the sterilization treatment of the contents can be performed. The weight-average fiber diameter is preferably 4 μm or more and 25 μm or less, more preferably 5 μm or more and 20 μm or less. The weight-average fiber diameter can be controlled by the fiber diameter and the weight per unit area of the nonwoven fabric. In controlling the fiber diameter, it is necessary to set the blowing conditions, drawing conditions, cooling conditions, and the like within appropriate ranges, but the control is not limited thereto. For example, the single-hole discharge amount is preferably 0.01 g/(min. hole) to 1.50 g/(min. hole), and the drawing air speed is preferably 500Nm³Hour/m to 2000Nm³The pressure is/hr/m. The fiber diameter and the basis weight are preferably balanced with required properties, other than strength, such as bacteria trapping properties and permeability, as a packaging material for sterilization.

The nonwoven fabric for a packaging material for sterilization in accordance with the second embodiment of the present invention has a texture coefficient of 1.0 or more and 5.0 or less. The texture coefficient is a parameter indicating the unevenness of the basis weight of the nonwoven fabric. The variation in weight per unit area is generally a factor directly related to the variation in strength, and a nonwoven fabric having a smaller variation in weight per unit area (a lower coefficient of basis weight) has a smaller variation in strength. When the nonwoven fabric is broken, the nonwoven fabric is broken from the portion having low strength (that is, the weight per unit area is small), and therefore, in order to achieve the effect of improving the latent strength and the same high strength, it is necessary to suppress the variation in strength. From this viewpoint, when the texture coefficient is 5.0 or less, the variation in strength due to the variation in basis weight of the nonwoven fabric can be suppressed. In addition, even from the viewpoint of bacteria barrier properties, large pores (so-called pinholes) due to variation in weight per unit area can be avoided, and a high degree of sterility can be maintained. The texture coefficient of the nonwoven fabric is preferably 4.5 or less, more preferably 4.0 or less. As a means for controlling the texture coefficient, a method of controlling the single-hole ejection amount in an appropriate range can be mentioned.

The nonwoven fabric for a packaging material for sterilization in the second embodiment of the present invention is preferably composed of continuous long fibers. The long fiber means a fiber length of 15mm or more. Since the filaments of the continuous long fibers are continuous as compared with the short fibers, the strength of the monofilaments is high, and as a result, the fabric strength and the stability of the production process can be achieved.

The nonwoven fabric for a packaging material for sterilization in the second embodiment of the present invention preferably has a puncture strength of 50N or more and 500N or less. If the piercing strength is 500N or less, the piercing strength can be sufficiently satisfied with a cutting tool such as a cutter, and the suitability for processing such as slitting can be satisfied. On the other hand, if the piercing strength is 50N or more, the bag will not be broken even with sharp medical instruments such as scalpels and scissors. The puncture strength is more preferably 70N or more and 450N or less, and still more preferably 100N or more and 400N or less.

In the packaging material for sterilization according to the second embodiment of the present invention, the tear strength is preferably 0.5N or more and 20N or less in any of the MD direction (machine direction, production direction of nonwoven fabric web) and the CD direction (width direction). When the tear strength is 20N or less, the scissors can be cut without any problem, and are excellent from the viewpoint of practical use. On the other hand, if the amount is 0.5N or more, the package shape can be maintained without breaking the bag by an external impact due to a sharp object. The tear strength is more preferably 0.7N or more and 15N or less, and still more preferably 0.9N or more and 10N or less.

In the packaging material for sterilization according to the second embodiment of the present invention, the tensile strength is preferably 30N/25mm or more and 300N/25mm or less in any of the MD direction and the CD direction. If the tensile strength is 30N/25mm or more, the tensile strength in the processing step can be endured in the production step. On the other hand, if it is 300N/25mm or less, the sheet is soft and the medical device is easily packaged, and therefore, it can be easily handled from the viewpoint of handling. The tensile strength is more preferably 40N/25mm or more and 250N/25mm or less, and still more preferably 50N/25mm or more and 200N/25mm or less.

The nonwoven fabrics for sterilization wrap according to the first and second embodiments of the present invention preferably have a chemical-vibration abrasion fuzz rating of 3.0 or more and 5.0 or less, which indicates the surface strength. When the number is 3.0 or more, the packaging material can be treated while wearing medical gloves used for medical treatment, and even if the surface is worn, fuzz due to the undulation of the yarn does not occur, and a clean environment can be maintained. Further, since the surface filaments are strongly bonded to each other, scattering of paper dust due to fluffing can be avoided even when the pouch is peeled off, and hence the cleaning and peeling properties can be achieved. The fuzz grade judgment is more preferably 3.5 or more, and further preferably 4.0 or more.

The sterilization wrap material according to the second embodiment of the present invention preferably has a laminated structure of nonwoven fabrics. By adopting the laminated structure, it is possible to design a layer that satisfies each required characteristic at a high level by itself, and to achieve high performance. The nonwoven fabric for a packaging material for sterilization in accordance with the second embodiment of the present invention preferably has, as the surface layer heat-seal surface, a fiber layer (a) composed of continuous long fibers having an average fiber diameter of 5 μm or more and 30 μm or less, and has, as the barrier layer, a fiber layer (B) composed of ultrafine fibers having an average fiber diameter of 0.1 μm or more and 4 μm or less, and the fiber layer (a) and the fiber layer (B) are laminated.

When the fiber layer (a) and the fiber layer (B) are laminated so as to be in contact with each other, the ultrafine fibers constituting the fiber layer (B) enter between the fibers constituting the fiber layer (a), and the fibers are uniformly arranged. This makes it possible to make the pore diameter of the laminated nonwoven fabric uniform, meaning that the bubble point of the maximum pore diameter is reduced, and therefore, a good bacteria-blocking property can be achieved. In some cases, the fiber layer (B) may be 2 or more. On the other hand, if the fiber diameter of the fibers constituting the fiber layer (a) is 5 μm or more, the monofilament strength is increased, and the laminated nonwoven fabric can achieve sufficient tensile and puncture strength and also stable processability. The fiber diameter of the fibers constituting the fiber layer (a) is more preferably 7 μm or more and 25 μm or less, and still more preferably 9 μm or more and 20 μm or less.

Further, if the fiber diameter of the fibers constituting the fiber layer (B) is 4 μm or less, the distance between the fibers is tight, so that a fine pore diameter can be achieved, and a good bacteria-blocking property can be obtained. From the viewpoint of air permeability and bacteria barrier properties, the fiber diameter of the fibers constituting the fiber layer (B) is more preferably 0.3 μm or more and 3 μm or less, and still more preferably 0.5 μm or more and 2.5 μm or less.

In order to more stably produce the nonwoven fabric for a packaging material for sterilization in the second embodiment of the present invention, a 3-layer laminated nonwoven fabric in which the fiber layer (B) is present as an intermediate layer between the 2 fiber layers (a) is preferable. When the fiber layers (a) are formed on both sides of the laminated nonwoven fabric, generation of fuzz and yarn ends can be suppressed when external force is applied to the surface of the nonwoven fabric during processing, and problems caused mainly by surface fuzz can be suppressed during production.

The method for producing each nonwoven fabric layer is not limited, and examples of the method for producing the fiber layer (a) include a spunbond method, a dry method, a wet method, and the like. Examples of the method for producing the fiber layer (B) include a dry method, a wet method, and other methods using ultrafine fibers, an electrospinning method, a melt blowing method, and the like, and a melt blowing method is preferable because an ultrafine nonwoven fabric can be easily and densely formed.

The method for laminating and integrating the fiber layer (a) and the fiber layer (B) is not particularly limited. Specifically, the thermal bonding may be a process using a calender or an integration (air through) method using hot air of high temperature, and the chemical bonding may be a method of applying an emulsion of a polyacrylate, a urethane resin, or the like. In particular, thermal bonding is very preferable as a medical packaging material for preventing contamination of foreign matter because it can maintain the tensile strength, puncture strength, and bending flexibility of the nonwoven fabric, and can form a multilayer nonwoven fabric layer without using an adhesive. A particularly preferred thermal joining method is processing by means of a calender. The calendering is a method of pressure bonding by a hot roll using a metal roll having irregularities such as embossing and a crepe pattern or a smooth roll having smoothness. The surface pattern of the roll having surface irregularities is not particularly limited as long as the fibers can be bonded to each other. This step also contributes to easy peelability. The thermal bonding step can be performed at a temperature lower than the melting point of the thermoplastic resin (preferably, the long thermoplastic resin fiber) by 50 ℃ to 120 ℃ and at a linear pressure of 100N/cm to 1000N/cm. When the linear pressure in the thermal bonding step is 100N/cm or more, a sufficient degree of bonding between fibers can be exhibited. Further, when the average flow rate pore diameter is 1000N/cm or less, the apparent density and the average flow rate pore diameter can be controlled within an appropriate range, and the necessary permeability of gas, vapor, or the like can be secured. In the case of the papermaking method, the fiber diameter of the short fibers produced by a known method may be controlled.

The fibers constituting the nonwoven fabric for packaging material for sterilization in the first and second embodiments of the present invention are preferably formed of a thermoplastic synthetic resin. Examples of the resin include polyolefin resins, polyester resins, and polyphenylene sulfide resins, specifically, high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, polypropylene (propylene homopolymer), polypropylene random copolymer, poly-1-butene, poly-4-methyl-1-pentene, polyolefin of ethylene-propylene random copolymer, and polyesters (polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate) which are homopolymers or copolymers of α -olefins such as ethylene, propylene, 1-butene, 1-hexane, 4-methyl-1-pentene, and 1-octene. In addition, copolymers or mixtures mainly composed of these resins are also preferable. In particular, by using a nonwoven fabric made of a resin having a melting point of 140 ℃ or higher, it is possible to cope with sterilization treatment requiring high temperature conditions such as steam sterilization. From this viewpoint, a polypropylene-based polymer is preferable, and a polyester-based polymer is more preferable. When these synthetic resins are used, high-temperature treatment can be realized in high-pressure steam sterilization treatment which is particularly high in heat resistance and frequently used in hospitals, and therefore, the treatment time can be reduced and efficient sterilization treatment can be performed. Since the heat resistance is high, a dense pore structure made of ultrafine fibers can be maintained, and invasion of bacteria can be effectively prevented even after the sterilization treatment. Further, since these polymers are not easily modified even by electron beam irradiation, they can cope with gas sterilization, electron beam sterilization, and the like which are mainstream in the field, and can form packaging materials for sterilization suitable for all treatment methods.

The nonwoven fabric for a packaging material for sterilization in accordance with the second embodiment of the present invention preferably has a water pressure resistance of 10cmH₂O or more. If the water pressure resistance is 10cmH₂When the amount is more than O, it is possible to prevent liquid entering from bacteria from entering into the package under a medical treatment environment with a large number of wet sites, and it is desirable to maintain the aseptic state. From this viewpoint, the water pressure resistance is more preferably 15cmH₂O or more, more preferably 20cmH₂O or more.

The average flow pore size of the nonwoven fabric for a packaging material for sterilization in the second embodiment of the present invention is preferably 0.5 μm or more and 20 μm or less. When the average flow pore size is 0.5 μm or more, sufficient fiber gaps are exhibited, air permeability can be secured, and the packaging material can be impregnated with the sterilization treatment. On the other hand, when the particle size is 20 μm or less, physical trapping of bacteria can be achieved, and the sterilized state can be maintained. From this viewpoint, the average flow pore diameter is more preferably 0.8 μm or more and 15 μm or less, and still more preferably 1.0 μm or more and 10 μm or less.

The nonwoven fabric for a packaging material for sterilization in accordance with the second embodiment of the present invention preferably has an atmospheric dust collection efficiency of 90% or more. When the atmospheric dust collection efficiency is 90% or more, invasion of bacteria into the package can be prevented, and the sterile state can be maintained at a high level. From this viewpoint, the atmospheric dust collection efficiency is more preferably 92% or more, and still more preferably 95% or more.

In general, a packaging material for sterilization is formed by utilizing only the air permeability of nonwoven fabric or the like, or a combination of an air permeable base material and a non-air permeable base material such as a transparent film is used, and therefore, heat sealability is sometimes required as the base material. The nonwoven fabric for a packaging material for sterilization of the present embodiment is made of a thermoplastic resin, and heat sealability is easily obtained. In particular, by using a resin material having a low melting point on one side, excellent heat seal strength is exhibited. When the laminated nonwoven fabric is used for heat sealing, hot-press sewing can be used for sterilizing the packaging material and sewing a surgical gown or the like.

The nonwoven fabric for a packaging material for sterilization in the first and second embodiments of the present invention is preferably subjected to water-repellent and alcohol-repellent treatment. The method of the water-repellent/alcohol-repellent treatment is not limited. For example, a coating method of applying a material having water repellency, a gas treatment method of activating the fiber surface with a gas having water repellency and alcohol repellency, or the like to perform a surface treatment can be used. The kind of the material or gas having water-and alcohol-repellent properties is not limited, and examples thereof include fluorine-based materials and silicon-based materials.

The surface coverage of the nonwoven fabric for a packaging material for sterilization in the first and second embodiments of the present invention is preferably 40% or more and 99% or less. Here, the "surface coverage" refers to a ratio of fibers covering the surface of the nonwoven fabric, and a detailed measurement method is as described later. When the surface coverage is 40% or more, when a film or the like is heat-sealed to a nonwoven fabric, penetration of a welding component from a gap on the surface of the nonwoven fabric can be prevented, excessive pressure bonding of sealing can be prevented, and generation of a thread waste when the film or the like is peeled off and opened can be suppressed. Thereby, good easy-to-peel and clean-to-peel properties can be achieved. Here, the easy peelability is an index of peel strength, and is considered to have an easy peelability when it is 27cN/25mm or less, more preferably 25cN/25mm or less. The cleaning releasability refers to the generation of lint, fuzz, breakage, and the like of a substrate such as a nonwoven fabric when the substrate is not peeled. Further, when product information is printed, an indicator for checking sterilization treatment, or the like is used, the penetration of ink into the back surface is suppressed, and good printability can be achieved. Further, the air permeability of the nonwoven fabric can be ensured by setting the content to 99% or less. The surface coverage is more preferably 50% or more and 95% or less.

The means for forming the range of the surface coverage is not limited, and a deformed filament in which the cross section of the filament is formed into a flat shape can be mentioned to improve the uniformity of the dispersion of the filament, but it is particularly effective to improve the uniformity of the dispersion of the filament. As a method for improving the uniformity of the dispersion of the yarn, the optimum production conditions for forming the fiber, such as the spinning temperature, the discharge amount, the fiber diameter, the fiber shape, the spinneret shape, the cooling conditions, and the charged state, can be mentioned. In particular, for the fiber shape, a circular shape is preferable. By forming the circular shape, shaking due to the flow of air is less likely to occur in the process of forming a cloth by discharging from the spinneret than in the case of a shaped yarn, unevenness in the dispersibility of the yarn due to contact with the yarn or the like is suppressed, and uniformity of the dispersion can be improved. The single-hole discharge amount is preferably 0.1 g/(min. hole) or more and 1.8 g/(min. hole) or less. When the amount is 0.1 g/(min. hole) or more, the discharge is stabilized, and the unevenness in the continuity of the fibers can be suppressed. Further, by setting the amount to 1.8 g/(min. hole) or less, the fibers are prevented from contacting each other, and unevenness due to welding can be suppressed. As other conditions, for example, the conditions for calendering are optimized.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(1) Porosity of the material

The porosity a (%) of the fiber layer was defined as W (g/m) in terms of the weight per unit area of the layer²) The thickness of the layer is h (μm), and the resin density is ρ (g/cm)³) The calculation is performed by the following equation:

a＝{1-(W/h)/ρ}×100

the thickness h of the fiber layer was measured by taking a cross section of the nonwoven fabric with an SEM device (JSM-6510, manufactured by Nippon electronics Co., Ltd.) under conditions of an acceleration voltage of 15kV and a working distance of 21mm, and the actually measured value at one position of the fiber layer was used.

In the method of discriminating the fiber layers, a portion where the average fiber diameter is changed by 2 μm or more from the average fiber diameter of each layer is defined as a boundary line of the fiber layers.

The total weight per unit area of the laminated nonwoven fabric was Wt (g/m) for the weight per unit area W of each layer²) Fiber when observing the cross section of the fiber layerThe cross-sectional area of the dimensional layer (I) is defined as A (μm)²) The total cross-sectional area of the laminated nonwoven fabric is At (mum)²) The calculation is performed by the following equation:

W＝Wt×A/At

(2) specific surface area

The measurement was carried out using an automatic specific surface area measuring apparatus (Gemini 2360, manufactured by Shimadzu corporation). The nonwoven fabric was rolled into a cylindrical shape and loaded into a specific surface area measuring cell (cell). The weight of the sample to be charged at this time is preferably about 0.20 to 0.60 g. The cell containing the sample was dried at 60 ℃ for 30 minutes, and then cooled for 10 minutes. Then, in the specific surface area measuring apparatus mounting groove, the following formula of BET was used by adsorption of nitrogen gas to the sample surface:

P/{V(P0-P)}＝1/(Vm×C)+{(C-1)/(Vm×C)}(P/P0)

{ formula (iv), P0: saturated water vapor pressure (Pa), V; nitrogen adsorption amount (mg/g), Vm: monolayer adsorption amount (mg/g), C: parameters (-) regarding heat of adsorption and the like are < 0. },

the specific surface area value was calculated.

The specific surface area St (m) of the whole laminated nonwoven fabric measured by the above-mentioned method²G), using the specific surface area S of the fiber layer (I)_I(m²G) and the specific surface area S of the fiber layer (II)_II(m²(iv)/g) represented by the following formula:

St＝S_I×W_I/Wt+S_II×W_II/Wt

{ wherein Wt is the total weight per unit area (m) of the laminated nonwoven fabric²/g)、W_IAnd W_IIThe basis weights (m) of the fiber layer (I) and the fiber layer (II), respectively²/g)。}

Specific surface area S_I、S_IIRespectively corresponding to the diameter d of the fiber_I、d_IIIn inverse proportion. Thus, d_IRelative to d_IIWhen it is sufficiently large, S_IViewed as being related to S_IIIs sufficiently small, and can be simplified into the following formula:

St≒S_II×W_II/Wt

therefore, the temperature of the molten metal is controlled,S_IIcalculated by the following equation:

S_II＝St×Wt/W_II

(3) heat seal Strength (Peel Strength)

The heat seal strength at the heat seal at an appropriate temperature was measured by the following method in accordance with JIS L1086. For a sample piece having a length of 10cm and a width of 2.5cm, 5 samples were prepared by bonding a film containing polypropylene as a sealant component having the same size to the fiber layer (I) and heat-sealing a portion 2cm from the end in parallel to the width direction of the sample piece. For the heat sealing, a hot press having a pair of upper and lower press bars (width 1cm, length 30cm) was used to heat-seal at a pressure of 0.5MPa for 1 second. Subsequently, the sample was mounted between chucks with a nip gap of 7cm so that the adhesive portion was centered between the chucks using a bench-top precision universal machine (AGS-1000D model manufactured by Shimadzu corporation), and the peel was performed at a tensile speed of 10 cm/min, and the peak strength exhibited at the time of the peel was defined as the peel strength. In this case, it can be said that the peeling property is easy if the peel strength is 27cN/25mm or less. Further, it can be said that the sheet has a cleaning and peeling property if there is no dust, lint generation, fuzz, breakage, or the like at the time of peeling.

(4) Number of filaments corresponding to 1cm per 1mg

The resin density was ρ (g/cm) for the number of filaments n (cm/mg) corresponding to 1cm per 1mg³) And d (μm) is a fiber diameter, and is calculated by the following equation:

n＝1/{ρ×π×(d/2×10^-4)²}

the fiber diameter d was measured by taking an image of the fiber diameter d with an SEM device (JSM-6510, manufactured by Nippon electronics Co., Ltd.) under conditions of an acceleration voltage of 15kV and a working distance of 21mm, and the average value of 100 fibers was used.

(5) Efficiency of atmospheric dust collection

The area was set to 78.5cm²(diameter 10cm) and air speed of 23.0L/min, and the air before and after passing through the nonwoven fabric was collected, and the particle size (effective diameter when the particles are assumed to be spherical) of particles (dust) of 1 μm or more in the collected air was measured by a particle counter (KC-01D 1 manufactured by RION, corrected with polystyrene particles), and the particle size was obtained by the following equation:

atmospheric dust collection efficiency (%) {1- (downstream particle number/upstream particle number) } × 100

The particle size is automatically calculated by the particle counter. Further, the higher the atmospheric dust collection efficiency is, the more preferable.

(6) Guli type air permeability (s/100ml)

The permeation time (unit, s/100ml) of 100ml of air was measured at room temperature using a Gerley air permeability measuring instrument (manufactured by Ontaki Seisakusho K.K.; type "B"). For one nonwoven fabric sample, 5 points were measured for each different position, and the average value was taken as the air permeability.

(7) Weight per unit area (g/m)²)

According to the method prescribed in JIS L-1906, a test piece 20cm in length by 25cm in width was measured by collecting 3 portions evenly in the width direction of the sample and 3 portions evenly in the flow direction, measuring the total of 9 portions, and calculating the average value of the measured masses as mass per unit area.

(8) Total thickness (mum)

The thickness of 10 sites was measured at equal intervals in the width direction according to the method prescribed in JIS L-1906, and the average value was obtained.

(9) Measurement of average fiber diameter and weight-average fiber diameter (. mu.m)

1cm square test pieces were cut out from a region of 20cm in width of the sample except for 10cm at each end of the sample (nonwoven fabric). The diameter of the fiber was measured at 30 points for each test piece by a microscope, and the average value of the measured values (the 2 nd position of the decimal point was rounded) was calculated as the average fiber diameter of the fiber constituting the sample. In the case of a single layer, the average fiber diameter is defined as the weight-average fiber diameter. In the case of the laminated structure, the average fiber diameter in each layer was measured, and the fiber diameter calculated by converting the weight ratio (using the following equation) was defined as the weight-average fiber diameter.

Dw＝ΣWi·Di＝Σ{(Ni·Di²)/(Ni·Di)}

In the formula, Wi is the weight fraction of the fiber diameter Di, Ni · Di/Σ Ni · Di, and Ni is the fiber number of the fiber diameter Di. }

(10) Coefficient of mass

Measured by a structure tester (FMT-MIII). A20X 30cm test piece was collected, and the piece was irradiated with a tungsten current of DC low voltage (6V30W) from below the sample placed on the diffusion plate. A transmission image obtained by imaging a range of 18 × 25cm with a CCD camera is divided into 128 × 128 pixels, and the intensity of light received by each pixel is measured to calculate the transmittance. The coefficient of variation of texture is a value obtained by dividing the standard deviation (σ) of the transmittance at each minute site (5mm × 5mm) of the measurement sample by the average transmittance (E) (the following formula), and the deviation of the minute basis weight is most clearly evaluated, and it can be said that the smaller the value, the higher the uniformity.

Variation coefficient of texture is sigma/E x 100

(11) Tensile Strength (N/25mm)

According to the method prescribed in JIS 8113, a test piece having a width of 25mm × a length of 200mm was fixed so that the distance between the clamps was 100mm, except that each end of the nonwoven fabric was 10cm, and the measurement was performed at a crosshead speed of 20 mm/min. The nonwoven fabric was collected at 5 positions per 1m in the width direction. The test piece was subjected to a load until it broke, and the average of the strength at the time of maximum load of the test piece in the Machine Direction (MD) and the width direction (CD) was determined.

(12) Puncture strength (N)

A needle having a diameter of 25mm and a tip radius of 12.5mm was mounted on a bench precision universal machine (AGS-1000D model manufactured by Shimadzu corporation), and a piercing test was carried out at a temperature of 23. + -. 2 ℃ and a needle moving speed of 50 mm/min. For one nonwoven fabric sample, 5-point measurements were made for each different location, and the average value was taken as the puncture strength.

(13) Tear Strength (N)

According to JIS L10855 & 5C method, pendulum (pendulum) method, except for 10cm at both ends of the nonwoven fabric sample, 20cm per width, 1 test piece of 65mm length by 100mm length in MD direction and CD direction was collected and measured using an Elmendorf type tear tester. The average of the measurements was calculated (1 place 4 of decimal point was rounded off by 5). The MD measurement data refers to a value obtained by tearing the nonwoven fabric in the MD direction.

(14) Mean flow pore size and bubble point (. mu.m)

As a measuring apparatus, a Perm-Porometer (model: CFP-1200AEX) manufactured by PMI was used. In this measuring apparatus, a nonwoven fabric is used as a sample, the nonwoven fabric is immersed in an immersion liquid having a known surface tension, a pressure is applied to the nonwoven fabric in a state where all pores of the nonwoven fabric are covered with a film of the immersion liquid, and the pore diameter of the pores calculated from the pressure at which the liquid film of the immersion liquid is broken and the surface tension of the immersion liquid is measured. As the immersion liquid, Silwick manufactured by PMI company was used, and after immersing the nonwoven fabric in the immersion liquid and sufficiently degassing, the following formula was used:

d＝C·r/P

{ wherein d (unit: μm) is the pore diameter of the filter, r (unit: N/m) is the surface tension of the immersion liquid, P (unit: Pa) is the pressure at which the liquid film having the pore diameter is broken, and C is the wetting tension of the immersion liquid and a predetermined constant such as the contact angle }. The flow rate (wetting flow rate, unit L/min) at which the pressure P applied to the filter immersed in the immersion liquid continuously changes from low pressure to high pressure was measured. In this measurement method, the value obtained by dividing the wetting flow rate at a certain pressure P by the drying flow rate at that pressure is referred to as the cumulative filter flow rate (unit%). The flow rate of the liquid film destroyed under a pressure with a cumulative filter flow rate of 50% was taken as the mean flow pore size. Further, the initial pressure is 0 because even the liquid film of the largest pore is not broken. When the pressure is gradually increased, the liquid film of the largest pore is broken to generate a flow rate, and the pore diameter is referred to as a bubble point.

(15) Water pressure resistance (cmH)₂O)

A test piece 15cm square was sampled and measured in accordance with JIS L1092, and the water pressure resistance was calculated from the average of the measured values.

(16) Efficiency of atmospheric dust collection

The area was set to 78.5cm²(diameter 10cm) and air speed 23.0L/min, and the air before and after passing through the measuring machine was collected, and particles (dust) having a particle size of 1 μm in the collected air were measured by a particle counter (manufactured by RION) and obtained by the following equation:

atmospheric dust collection efficiency (%) [1- (downstream particle count/upstream particle count) ] × 100

(17) Surface coverage (%)

A test piece of 1cm square was cut out from the sample, observed at a magnification of 500 times, and the uneven structure on the surface was measured. Then, an area S1 existing at a position of 0 μm or more and d μm or less in the depth direction from the outermost surface position is measured, and a ratio of the area S2 to the entire visual field is calculated as the coverage P. Here, d is the average fiber diameter of the surface layer. As a measuring apparatus, the uneven structure of the surface was measured by using a macro mirror VR-3000 manufactured by KEYENCE CORPORATION, One shot 3D, and the average fiber diameter D of the fibers constituting the sample was measured by measuring the diameter of 30 points of the fibers using JSM-6510 manufactured by Japan electronic Co., Ltd, and calculating the average value of the measured values (rounding off the 2 nd digit of the decimal point). The following equation was used for the calculation.

Coverage rate P (%) ═ S1/S2X 100

[ examples 1 to 8]

Using a polypropylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 230 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As a fiber material, PP resin was used, and the PP resin melted by an extruder was extruded from a spinneret nozzle having a spinneret nozzle diameter of 0.22 mm. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. The obtained web was then subjected to calendering at a linear pressure of 10kg/cm using a low-hardness roll having a type a durometer hardness of 70 to adjust to a desired porosity, thereby obtaining a packaging material for sterilization.

[ examples 9 to 14]

Continuous filament produced by spun-bonding method using polyester resinAn SB-MB-SB laminated nonwoven fabric was produced by laminating a web directly on a nonwoven fabric by a melt-blown method and further laminating a continuous filament nonwoven fabric produced by a spunbond method thereon. The amount of fibers in each layer was adjusted by the single-hole discharge amount and the line speed. The fiber diameter of each layer is adjusted to 500-2000 Nm³Varying the traction air velocity in the range of/hr/m. Further, each nonwoven fabric was obtained by integrating the smooth rolls by calendering and adjusting the thickness and the apparent density so as to have a desired thickness. In the spunbond method, the dispersion is varied to form a desired texture by appropriately adjusting the discharge conditions (single-hole discharge amount) and the equipment conditions (special dispersion device and spinneret design).

[ examples 15 to 20]

Using a polypropylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 230 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As the fiber material, a PP resin was used, and the PP resin melted by an extruder was extruded. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Further, by adjusting the hole pitch of the spinneret and the flow of the drawing and cooling air, the fusion caused by the contact between the filaments is suppressed, and the dispersion of the fibers is made uniform. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. Then, the obtained web sheet was subjected to smooth calendering using a combination of a low-hardness roll having a durometer hardness of type a of 70 and a high-hardness roll made of metal at a linear pressure of 10kg/cm, and the roll temperature and the processing speed were optimized to adjust the surface coverage to a desired level, thereby obtaining a packaging material for sterilization.

[ example 21]

Using a polyethylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 160 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As a fiber material, a PP resin was used, and a PE resin melted by an extruder was extruded. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PE resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. Then, the obtained web was subjected to calendering using a combination of a low hardness roll having a durometer hardness of type A of 70 and a high hardness roll at a linear pressure of 10kg/cm to adjust the porosity to a desired level, thereby obtaining a packaging material for sterilization.

[ example 22]

Using a polypropylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 230 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As the fiber material, a PP resin was used, and the PP resin melted by an extruder was extruded. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Further, by adjusting the hole pitch of the spinneret and the flow of the drawing and cooling air, the fusion caused by the contact between the filaments is suppressed, and the dispersion of the fibers is made uniform. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. In addition, a flat profile spinneret was used as the SB spinneret. Then, the obtained web sheet was subjected to smooth calendering using a combination of a low-hardness roll having a durometer hardness of type a of 70 and a high-hardness roll made of metal at a linear pressure of 10kg/cm, and the roll temperature and the processing speed were optimized to adjust the surface coverage to a desired level, thereby obtaining a packaging material for sterilization.

Comparative examples 1 and 2

Using a polypropylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 230 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As a fiber material, PP resin was used, and the PP resin melted by an extruder was extruded from a spinneret nozzle having a spinneret nozzle diameter of 0.22 mm. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. Then, the obtained web was calendered at a linear pressure of 40kg/cm using a roll having a type a durometer hardness of 100 to obtain a packaging material for sterilization.

Comparative examples 3 and 4

Using a polypropylene resin, a long fiber group of filaments was extruded toward a moving collecting web at a spinning temperature of 230 ℃ by a spunbond method, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As a fiber material, PP resin was used, and the PP resin melted by an extruder was extruded from a spinneret nozzle having a spinneret nozzle diameter of 0.22 mm. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. Then, the obtained web was calendered at a linear pressure of 10kg/cm using a roll having a type a durometer hardness of 100 to obtain a packaging material for sterilization.

Comparative examples 5 and 6

A long fiber group of filaments was extruded at a spinning temperature of 300 ℃ toward a moving collecting web by a spunbond method using a polyester resin, and spun at a spinning speed of 4500 m/min to form a thermoplastic resin long fiber web on the collecting web, thereby producing a nonwoven fabric. The web was blown out onto the spunbond nonwoven fabric produced as described above by the following meltblowing method. As a fiber material, PP resin was used, and the PP resin melted by an extruder was extruded from a spinneret nozzle having a spinneret nozzle diameter of 0.22 mm. The thermoplastic resin is drawn and refined by appropriately selecting the melting temperature of the PP resin, the temperature of the spinning gas, the single-hole discharge amount of the molten resin, and the like in the extruder. Then, SB spun fibers similar to those described above were discharged onto the MB nonwoven fabric to produce an SB-MB-SB laminated nonwoven fabric. The obtained web was then calendered at a linear pressure of 10kg/cm using a rubber roller to adjust the porosity to a desired level, thereby obtaining a packaging material for sterilization.

Comparative example 7

A long fiber web was obtained by a spunbond method in the same manner as in example 1 under the condition that the single hole discharge rate was 2.0 g/(min hole). Note that the fiber diameter is 400m by forming the drawing air³The range of/hr/m. Further, the nonwoven fabric was obtained by integrating the nonwoven fabric with smooth rolls and adjusting the thickness and the apparent density so as to have a desired thickness.

The nonwoven fabric structures of examples 1 to 22 and comparative examples 1 to 7 and the obtained nonwoven fabrics have various properties as shown in tables 1-1 to 1-4 below.

[ tables 1-1]

[ tables 1-2]

[ tables 1 to 3]

[ tables 1 to 4]

Industrial applicability

The nonwoven fabric for a packaging material for sterilization of the first embodiment of the present invention is a nonwoven fabric having both easy peelability and barrier properties by laminating a fiber layer having a low porosity and a fiber layer having a high specific surface area and a large number of filaments, and has a specific fiber structure and a highly controlled pore size, and can be produced at a high yield and a low cost, and further has a high strength and an appropriate pore size, and therefore can cope with all sterilization treatment methods, and can maintain the sterile state inside the packaging material at a high level, and therefore can be suitably used as a packaging material for sterilization of medical instruments for preventing infectious diseases.