Packaging material for sterilization and air-permeable material

Abstract

A packaging material (1) for sterilization comprises an air-permeable material (10) and a non-air-permeable material (20) that is joined to part of the air-permeable material (10) via a seal part (6). This air-permeable material (10) has an air-permeable base material (11) and a coating layer (12). The coating layer (12) contains an ethylene-vinyl acetate copolymer and a styrene acrylic compound. When the sealing strength of the seal part (6) is measured in conformance with JIS Z 0238:1998, a maximum value (P1) of the sealing strength is present in a first region (R1) in which the relative movement distance of a grip (90) is 0-4 mm, and a maximum value (P2) of the sealing strength is present in a second region (R2) in which the relative movement distance of the grip (90) is 4-17 mm. The maximum value (P2) is no more than 85% of the maximum value (P1).

Description

Packaging material for sterilization and breathable material

[0001] The present disclosure relates to a packaging material for sterilization and a breathable material.

[0002] Conventionally, medical sterilization bags for storing medical articles have been known (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a medical sterilization bag in which the peripheral edges of overlapping flexible and bacteria-impermeable main sheets (non-breathable materials) are tightly joined to form a bag body, and the bag body has both side surfaces facing each other, and a sterile storage portion for storing a medical article between the both side surfaces. Further, in this medical sterilization bag, an opening portion for taking out the article from the storage portion is formed at a required site of the bag body, and a flexible, breathable and bacteria-impermeable cover sheet (breathable material) is located on the outer surface of the bag body to cover the entire area of the opening portion and the peripheral region of the opening portion. Furthermore, in this medical sterilization bag, the peripheral edge of the cover sheet is peelably and tightly joined to the outer surface of the bag body, and the article, the peripheral region, and the inner surface of the cover sheet facing the outer surface of the bag body are maintained in a sterile state.

[0004] Japanese Unexamined Patent Publication No. 2001-286538

[0005] In such a sterilization bag, a so-called peel-open method can be adopted as an unsealing method for opening the sterilization bag. In the peel-open method, since the sealing portion is continuously peeled off, it is desirable that the peeling can be performed smoothly without applying extra force once the peeling is started. On the other hand, in conventional sterilization bags, the sealing strength of the sealing portion does not decrease even after peeling is started, so a load may be applied when opening the sterilization bag.

[0006] The present disclosure has been made in view of such points, and an object thereof is to provide a packaging material for sterilization and a breathable material that can improve unsealing properties.

[0007] Embodiments of the present disclosure relate to the following [1] to [9].

[0008] [1] A sterilization packaging material comprising a gas-permeable breathable material and a non-breathable material joined to a part of the breathable material via a sealing portion, wherein the breathable material comprises a breathable substrate and a coating layer applied to the breathable substrate, the coating layer comprises an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the sealing portion, when the sealing strength is measured using a pair of grips in accordance with JIS Z0238:1998, has a maximum sealing strength P1 in a first region where the relative movement distance of the grips is 0 mm or more and 4 mm or less, and has a maximum sealing strength P2 in a second region where the relative movement distance of the grips is 4 mm or more and 17 mm or less, and the maximum sealing strength P2 is 85% or less of the maximum sealing strength P1.

[0009] [2] The sealing portion has a minimum value B1 of sealing strength in the second region when the sealing strength is measured using a pair of grips in accordance with JIS Z0238:1998, and the minimum value B1 is 30% or more of the maximum value P1, as described in [1].

[0010] [3] The sterilization packaging material according to [1] or [2], wherein the maximum value P1 is 2.0 N / 15 mm or more and 10.0 N / 15 mm or less, and the seal strength in the second region is 0.6 N / 15 mm or more and 8.0 N / 15 mm or less.

[0011] [4] The sterilization packaging material according to any one of [1] to [3], wherein the content of the styrene acrylic compound in the coating layer is 30% or more and 80% or less.

[0012] [5] The sterilization packaging material according to any one of [1] to [4], wherein the breathable substrate is made of high-density polyethylene fibers or polypropylene fibers.

[0013] [6] The non-permeable material comprises a base material including an outer surface and an inner surface, and a sealant layer laminated on the inner surface of the base material and bonded to a part of the permeable material, according to any one of [1] to [5].

[0014] [7] The non-permeable material is a single layer or a blister sheet, and is a sterilization packaging material according to any one of [1] to [5].

[0015] [8] A sterilization packaging material comprising a gas-permeable breathable material and a non-breathable material bonded to a part of the breathable material, wherein the breathable material comprises a breathable substrate and a coating layer applied to the breathable substrate, the coating layer comprises an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the content of the styrene-acrylic compound in the coating layer is 30% or more and 80% or less.

[0016] [9] A breathable material having gas permeability, comprising a breathable substrate and a coating layer applied to the breathable substrate, wherein the coating layer contains an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the content of the styrene-acrylic compound in the coating layer is 30% or more and 80% or less.

[0017] According to this disclosure, the ease of opening sterilization packaging materials can be improved.

[0018] Figure 1 is a front view showing an example of a sterilization packaging material according to one embodiment of the present disclosure. Figure 2 is a cross-sectional view of a sterilization packaging material according to one embodiment of the present disclosure (cross-sectional view along line II-II in Figure 1). Figure 3 is a cross-sectional view showing an example of a non-permeable material according to one embodiment of the present disclosure. Figure 4 is a perspective view showing a sample for measuring seal strength. Figure 5 is a diagram illustrating a method for measuring seal strength. Figure 6 is a graph illustrating the seal strength of a sterilization packaging material according to one embodiment of the present disclosure. Figure 7A is a cross-sectional view showing a method for manufacturing a sterilization packaging material according to one embodiment of the present disclosure. Figure 7B is a cross-sectional view showing a method for manufacturing a sterilization packaging material according to one embodiment of the present disclosure. Figure 7C is a cross-sectional view showing a method for manufacturing a sterilization packaging material according to one embodiment of the present disclosure. Figure 7D is a cross-sectional view showing a method for manufacturing a sterilization packaging material according to one embodiment of the present disclosure. Figure 8 is a graph showing the seal strength of a sterilization packaging material according to Example 1. Figure 9 is a graph showing the seal strength of a sterilization packaging material according to Example 2. Figure 10 is a graph showing the seal strength of a sterilization packaging material according to Example 3. Figure 11 is a graph showing the seal strength of the sterilization packaging material according to Example 4. Figure 12 is a graph showing the seal strength of the sterilization packaging material according to Example 6. Figure 13 is a graph showing the seal strength of the sterilization packaging material according to Comparative Example 1. Figure 14 is a graph showing the seal strength of the sterilization packaging material according to Comparative Example 2. Figure 15 is a graph showing the seal strength of the sterilization packaging material according to Comparative Example 3. Figure 16 is a graph showing the seal strength of the sterilization packaging material according to Comparative Example 4.

[0019] An embodiment will be described below with reference to the drawings. Figures 1 to 7D show an embodiment. The following figures are schematic representations. Therefore, the size and shape of each part are exaggerated as appropriate to facilitate understanding. Furthermore, it can be modified as appropriate without departing from the technical concept. In the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as dimensions and material names of each component described in this specification are examples of embodiments and are not limited to them; they can be selected and used as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, will be interpreted to include not only their strict meaning but also substantially the same state.

[0020] <Sterilization Packaging Material> First, an overview of the sterilization packaging material 1 according to one embodiment of the present disclosure will be described with reference to Figure 1.

[0021] As shown in Figures 1 and 2, the sterilization packaging material 1 comprises a gas-permeable breathable material 10 and a non-breathable material 20 joined to a part of the breathable material 10. The non-breathable material 20 is joined to a part of the breathable material 10 via a sealing portion 6. Here, we will first describe the breathable material 10.

[0022] <<Breathable Material>> As described above, the breathable material 10 is gas permeable. On the other hand, the breathable material 10 is impermeable to microorganisms. For this reason, as will be described later, the breathable material 1 is configured to maintain the sterile state of the instruments after sterilization. The breathable material 10 has a breathable base material 11 that has breathability and a coating layer 12 applied to the breathable base material 11. The breathable base material 11 may be a nonwoven fabric. In this case, the fibers of the nonwoven fabric may be joined together by wet, dry, direct, spunbond, thermal bond, or chemical bond methods. The fiber length of the nonwoven fabric is not particularly limited. The fibers of the nonwoven fabric may be short fibers or long fibers. From the viewpoint of suppressing the generation of fiber debris at the cut part and reducing thread shedding, a nonwoven fabric with long fibers formed by the spunbond method can be preferably used.

[0023] In this embodiment, the breathable substrate 11 is made of polyolefin fibers. That is, as the raw material for the fibers forming the nonwoven fabric, general polyethylene or polypropylene or other polyolefins can be used. As a result, as will be described later, dust generation can be suppressed compared to substrates made from paper, such as sterile paper. The breathable substrate 11 may also be made of high-density polyethylene fibers among the polyolefin fibers. As a result, the strength and heat resistance of the breathable substrate 11 can be improved.

[0024] The basis weight of the nonwoven fabric is not particularly limited and depends on the required specifications, up to 5 g / m². ２ More than 100g / m ２ The following types may be used interchangeably: Nonwoven fabric with a basis weight of 5 g / m². ２ As a result, the strength of the breathable material 10 can be maintained well. Also, the basis weight of the nonwoven fabric is 100 g / m². ２ The following factors can reduce manufacturing costs.

[0025] The coating layer 12 faces the non-permeable material 20 (see Figure 2). The coating layer 12 is formed by a heat-sealing agent applied to the surface of the fibers constituting the nonwoven fabric. In this case, the heat-sealing agent can be applied to the fiber surface by known coating methods such as gravure coating or dip coating. The fibers of the nonwoven fabric may be randomly intertwined. Alternatively, a nonwoven fabric in which thicker fibers are regularly and in a mesh-like manner and joined together may be used.

[0026] In this embodiment, the coating layer 12 contains an ethylene-vinyl acetate copolymer (EVA) and a styrene-acrylic compound.

[0027] In the coating layer 12, the content of the styrene-acrylic compound may be 30% or more and 80% or less. In general, if the content of the styrene-acrylic compound is increased, the seal strength of the seal portion 6 may decrease. Therefore, by having a styrene-acrylic compound content of 30% or more, it is possible to suppress the seal strength of the seal portion 6 from becoming too high. In particular, by having a styrene-acrylic compound content of 30% or more, it is possible to suppress the seal strength in the second region R2 of the seal portion 6, which will be described later, from becoming too high. In other words, since the seal strength in the second region R2, which will be described later, can be controlled to a value below the desired value, the ease of opening the sterilization packaging material 1 can be improved. Furthermore, by having a styrene-acrylic compound content of 80% or less, it is possible to suppress a decrease in the heat sealability of the seal portion 6.

[0028] In the coating layer 12, the content of the styrene-acrylic compound may be 30% or more, 40% or more, or 50% or more. Furthermore, in the coating layer 12, the content of the styrene-acrylic compound may be 80% or less, 70% or less, or 65% or less.

[0029] The gas permeability (resistance to air permeability) of the permeable material 10 may be 10 seconds / 100 mL or more, or 20 seconds / 100 mL or more. The gas permeability of the permeable material 10 shall be measured in accordance with the Gurley method of JIS P 8117:2009.

[0030] As such a breathable material 10 (nonwoven fabric), for example, Tyvek® 1073B (product number) manufactured by DuPont de Nemours, Inc. can be used.

[0031] Although not shown in the illustrations, a printed layer of characters, patterns, or barcodes may be formed on the breathable material 10. Known printing techniques may be employed. Generally, the surface of the breathable material 10, which forms the printing surface, is rougher than that of a film or printing paper. Therefore, the printed layer is preferably printed by gravure printing, letterpress printing, or flexographic printing.

[0032] Next, we will describe the non-permeable material 20.

[0033] <<Non-permeable material>> As shown in the figure, the non-permeable material 20 has a base material 21 including an outer surface 21a and an inner surface 21b, and a sealant layer 22 which is laminated on the inner surface 21b of the base material 21 and bonded to a part of the permeable material 10. In this case, as shown in Figure 3, the base material 21 may be composed of a single layer. Although not shown, if the base material 21 also has a sealant function (sealing function), the non-permeable material 20 may be a single layer.

[0034] The substrate 21 and the sealant layer 22, etc., may be bonded together via an adhesive layer (not shown). The adhesive layer is an adhesive layer or thermoplastic resin layer formed to bond any two layers by lamination. As the adhesive for lamination, for example, one-component or two-component curing or non-curing type vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and others, solvent-based, water-based, or emulsion-type laminating adhesives can be used. As the coating method for the above adhesive, for example, it can be applied by direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, fontein method, transfer roll coating, or other methods. Furthermore, as the material for the thermoplastic resin layer, for example, the same material as for the sealant layer 22 can be used.

[0035] The following describes each layer that makes up the non-breathable material 20.

[0036] <<<Substrate>>> The substrate 21 is, for example, a layer that supports the sealant layer 22 and increases the overall strength of the sterilization packaging material 1.

[0037] As the base material 21, a multilayer or single-layer film may be used. The material of the base material 21 may be a polyethylene-based resin, a polyethylene terephthalate-based resin, a mixture thereof, or a polyamide-based resin. For example, as the base material 21, a film composed of polyethylene and polyethylene terephthalate, a polyethylene film, or a polyethylene terephthalate film may be used.

[0038] As the above-mentioned resin film or sheet, a uniaxially stretched stretched film may be used, and a biaxially stretched stretched film may also be used.

[0039] The thickness T (see FIG. 3) of such a base material 21 may be, for example, 5 μm or more and 30 μm or less.

[0040] <<<Sealant Layer>>> The sealant layer 22 is a layer for bonding the air-permeable material 10 and the non-air-permeable material 20 to each other. The sealant layer 22 is the innermost layer in the non-air-permeable material 20. The sealant layer 22 faces the coat layer 12 of the air-permeable material 10. This sealant layer 22 is bonded to the air-permeable material 10 in the sterilization packaging material 1.

[0041] In the present embodiment, the sealant layer 22 is composed of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), or a mixture of linear low-density polyethylene and low-density polyethylene. The sealant layer 22 may be composed of the above-mentioned resin film or sheet, or a coating film thereof, or the like.

[0042] The thickness of the sealant layer 22 may be, for example, 20 μm or more and 150 μm or less. The sealant layer 22 may be composed of a single layer, or may be composed of a plurality of layers.

[0043] Referring again to Figure 1, the sterilization packaging material 1 includes an upper edge 2, a lower edge 3 facing the upper edge 2 in a first direction d1, and a pair of side edges 4 extending from the upper edge 2 to the lower edge 3 along the first direction d1. Among these, the lower edge 3 is formed with an opening 5 for accommodating an instrument to be sterilized. This opening 5 is a portion that is closed after the instrument is accommodated in the sterilization packaging material 1. The first direction d1 is the conveyance direction of the air-impermeable material 20 when producing the air-impermeable material 20, which is the so-called MD (Machine Direction). In the example shown in Figure 1, the upper edge 2 and the lower edge 3 extend in a second direction d2 orthogonal to the first direction d1, and the sterilization packaging material 1 has a rectangular outer shape. Although not illustrated, the upper edge 2 and the lower edge 3 may extend in a direction inclined relative to the second direction d2.

[0044] In the sterilization packaging material 1, the air-permeable material 10 and the air-impermeable material 20 are bonded to each other at the seal portion 6. The seal portion 6 has a pair of first seal portions 7 extending along the side edges 4 of the sterilization packaging material 1, and a second seal portion 8 extending from one first seal portion 7 to the other first seal portion 7.

[0045] Among these, the second seal portion 8 has a V-shape. In this case, the second seal portion 8 is formed such that the tip of the V-shape faces the upper edge 2 side. Thereby, when opening the sterilization packaging material 1, the air-permeable material 10 and the air-impermeable material 20 at the second seal portion 8 are easily separated from each other starting from the tip of the V-shape. The second seal portion 8 is not limited to a V-shape, and may have any shape such as a rectangular shape.

[0046] The method for forming the seal portion 6 is not particularly limited. For example, the seal portion 6 may be formed by welding the air-permeable material 10 and the air-impermeable material 20 together by heating (heat sealing) or the like. At this time, as the heat sealing method, a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing or ultrasonic sealing can be adopted.

[0047] Next, the seal strength of the seal portion 6 will be described.

[0048] Here, the seal strength of the seal portion 6 is measured in accordance with "7. Heat seal strength test of bags" of JIS Z0238:1998.

[0049] Specifically, when measuring the seal strength of the seal portion 6, first, a test sample S (see Figure 4) is prepared. The sample S shown in Figure 4 is a sample cut from the sterilization packaging material 1 so that the width direction of the sample S coincides with the longitudinal direction of the seal portion 6, as shown in Figure 1. When preparing the test sample S, the seal portion 6 is cut out so that the width W is 15.0 mm ± 0.1 mm and the unfolded length L is 100 mm or more. If it is not possible to obtain a sample with an unfolded length L of 100 mm or more, the unfolded length should be 100 mm or more in accordance with JIS Z0238:1998.

[0050] Next, as shown in Figure 5, the sample S is attached to a pair of grips 90 of the tensile testing machine in a T-shape, rotated 180°. At this time, the distance between the grips 90 should be 50 mm or more.

[0051] Next, the grips 90 are moved in opposite directions. At this time, the grips 90 are moved in opposite directions until the seal portion 6 of the sample S is completely broken. The tensile load (N / 15 mm) applied by the grips 90 is defined as the sealing strength of the seal portion 6. The relative movement speed of the grips 90 is set to 300 mm / min ± 20 mm / min.

[0052] The test environment will be set to a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. Sample S will be placed in the test environment for 16 hours before the start of the test.

[0053] As shown in Figure 6, in this embodiment, the seal portion 6 has a maximum seal strength P1 in the first region R1. The maximum value P1 is the maximum seal strength in the first region R1. The first region R1 is the region in which, when the seal strength is measured using a pair of grips 90 in accordance with JIS Z0238:1998, the relative movement distance of the grips 90 is 0 mm or more and 4 mm or less. In this way, because the seal portion 6 has a maximum seal strength P1 in the first region R1, the seal portion 6 is less likely to peel off unintentionally. Therefore, the airtightness of the sterilization packaging material 1 can be improved. As a result, the sterile state of the instruments after sterilization can be maintained inside the sterilization packaging material 1.

[0054] The maximum seal strength P1 may be between 2.0 N / 15 mm and 10.0 N / 15 mm. A maximum seal strength P1 of 2.0 N / 15 mm or more can more effectively improve the airtightness of the sterilization packaging material 1. Specifically, a maximum seal strength P1 of 2.0 N / 15 mm or more can prevent the seal portion 6 from peeling off even when a predetermined force is applied to the sterilization packaging material 1, thus maintaining the shape of the sterilization packaging material 1. Therefore, the sterile state of the instruments after sterilization can be more effectively maintained within the sterilization packaging material 1. Furthermore, a maximum seal strength P1 of 10.0 N / 15 mm or less can prevent the sterilization packaging material 1 from becoming difficult to open.

[0055] Furthermore, as shown in Figure 6, the seal portion 6 has a maximum seal strength P2 in the second region R2. The maximum seal strength P2 is the maximum value of the seal strength in the second region R2. The maximum seal strength P2 may be 85% or less of the maximum value P1. The second region R2 is the region in which, when the seal strength is measured using a pair of grips 90 in accordance with JIS Z0238:1998, the relative movement distance of the grips 90 is 4 mm or more and 17 mm or less. In this way, by making the maximum seal strength P2 in the second region R2 85% or less of the maximum value P1, the seal strength of the seal portion 6 can be reduced in the second region R2, and the ease of opening the sterilization packaging material 1 can be improved.

[0056] Furthermore, as shown in Figure 6, the seal portion 6 has a minimum seal strength B1 in the second region R2. The minimum value B1 is the minimum seal strength in the second region R2. The minimum seal strength B1 may be 30% or more of the maximum value P1. In this way, by having the minimum seal strength B1 in the second region R2 be 30% or more of the maximum value P1, it is possible to prevent the seal strength of the seal portion 6 from becoming too low in the second region R2. This improves the airtightness of the sterilization packaging material 1. As a result, the sterile state of the instruments after sterilization can be maintained inside the sterilization packaging material 1. Note that the seal strength in the second region R2 and the seal strength in the first region R1 described above can be controlled by adjusting the content of ethylene-vinyl acetate copolymer (EVA) and styrene-acrylic compound used in the coating layer 12.

[0057] The seal strength in the second region R2 may be between 0.6 N / 15 mm and 8.0 N / 15 mm. A seal strength of 0.6 N / 15 mm or more in the second region R2 can more effectively improve the airtightness of the sterilization packaging material 1. Therefore, the sterile state of the instruments after sterilization can be more effectively maintained within the sterilization packaging material 1. A seal strength of 8.0 N / 15 mm or less in the second region R2 can prevent the sterilization packaging material 1 from becoming difficult to open.

[0058] The sterilization packaging material 1 shown in Figure 1 is suitably used, for example, when sterilizing medical instruments, etc., by gas sterilization with ethylene oxide gas (EOG) or steam sterilization.

[0059] As mentioned above, the opening 5 formed on the lower edge 3 is closed after the instrument is placed inside the sterilization packaging material 1. For this reason, in the illustrated example, the sterilization packaging material 1 is a so-called four-sided sealed packaging bag. However, it is not limited to this, and the sterilization packaging material 1 may be any type of sealing bag, such as a side-sealed type, a two-sided sealed type, a three-sided sealed type, an envelope-type sealed type, a pleated sealed type, a flat-bottom sealed type, a gusseted bag type, a single-gusseted bag type, a standing pouch type, or a square-bottom sealed type.

[0060] Next, the operation of the sterilization packaging material 1 according to this embodiment, which has the above configuration, will be explained. Here, first, the manufacturing method of the sterilization packaging material 1 shown in Figure 1 will be explained with reference to Figures 7A to 7D.

[0061] <Method for Manufacturing Sterilization Packaging Material> First, a breathable material 10 is prepared as shown in Figure 7A. The breathable material 10 has a breathable base material 11 and a coating layer 12. The breathable base material 11 may be a nonwoven fabric made of high-density polyethylene fibers. The coating layer 12 contains ethylene-vinyl acetate copolymer (EVA) and a styrene-acrylic compound. Although not shown in the figure, the breathable material 10 may be stored in a rolled state.

[0062] Furthermore, as shown in Figure 7B, an airtight material 20 is prepared. In this case, the resin film as the base material 21 and the resin film as the sealant layer 22 are bonded to each other, for example, by a dry lamination method. In this way, the airtight material 20 is obtained as shown in Figure 7B. Although not shown in the figures, the airtight material 20 may be stored in a rolled state.

[0063] Next, a sterilization packaging material 1 is prepared using the breathable material 10 and the non-breathable material 20.

[0064] In this case, as shown in Figure 7C, for example, the breathable material 10 is continuously unwound from a roll of breathable material 10. Similarly, the non-breathable material 20 is continuously unwound from a roll of non-breathable material 20. Then, the breathable material 10 and the non-breathable material 20 are stacked on top of each other so that the sealant layer 22 of the non-breathable material 20 (see Figure 3, etc.) faces the coating layer 12 of the breathable material 10.

[0065] Next, as shown in Figure 7D, the positions corresponding to the vicinity of the pair of side edges 4 of the sterilization packaging material 1 are heat-sealed to form the first seal portion 7. At this time, a second seal portion 8 is formed at the position corresponding to each individual sterilization packaging material 1. The dashed lines (two-dot lines) shown in Figure 7D indicate the regions corresponding to each individual sterilization packaging material 1.

[0066] In this way, the sterilization packaging material 1 is obtained. Although not shown in the figures, the sterilization packaging material 1 may be stored in a rolled state. Alternatively, the sterilization packaging material 1 may be cut into individual pieces and stored in that form.

[0067] Subsequently, the instruments to be sterilized are placed inside the sterilization packaging material 1 through an opening 5 formed in the lower edge 3 (see Figure 1) of the sterilization packaging material 1. Next, a seal is formed by heat sealing the vicinity of the lower edge 3, closing the lower edge 3 of the sterilization packaging material 1. In this way, the instruments are sealed inside the sterilization packaging material 1. Then, the instruments contained inside the sterilization packaging material 1 are sterilized by gas sterilization or steam sterilization, etc. As described above, the breathable material 10 of the sterilization packaging material 1 is impermeable to microorganisms but permeable to gas. Therefore, gas or steam enters the sterilization packaging material 1 through the breathable material 10 and sterilizes the instruments contained inside the sterilization packaging material 1. In addition, because the breathable material 10 is impermeable to microorganisms, the sterile state of the instruments after sterilization is maintained inside the sterilization packaging material 1.

[0068] As described above, according to this embodiment, the sterilization packaging material 1 comprises a gas-permeable breathable material 10 and a non-breathable material 20 joined to a part of the breathable material 10 via a sealing portion 6. The breathable material 10 comprises a breathable substrate 11 and a coating layer 12 applied to the breathable substrate 11. The coating layer 12 contains an ethylene-vinyl acetate copolymer and a styrene-acrylic compound. The sealing portion 6 has a maximum sealing strength P1 in a first region R1 where the relative movement distance of the grips 90 is 0 mm or more and 4 mm or less, when the sealing strength is measured using a pair of grips 90 in accordance with JIS Z0238:1998. The sealing portion 6 has a maximum sealing strength P2 in a second region R2 where the relative movement distance of the grips 90 is 4 mm or more and 17 mm or less. The maximum sealing strength P2 is 85% or less of the maximum sealing strength P1. Thus, in the second region R2, by having the maximum value P2 be 85% or less of the maximum value P1, the sealing strength of the seal portion 6 can be reduced in the second region R2, thereby improving the ease of opening the sterilization packaging material 1. In other words, after the start of opening the sterilization packaging material 1, the sterilization packaging material 1 can be easily opened without applying any further force. For this reason, the airtightness of the sterilization packaging material 1 is maintained before opening, and after the start of opening the sterilization packaging material 1, the sterilization packaging material 1 can be easily opened. The improvement in the ease of opening the sterilization packaging material 1 will be explained in the embodiments described later.

[0069] Furthermore, according to this embodiment, the content of the styrene-acrylic compound in the coating layer 12 is 30% to 80%. By having a styrene-acrylic compound content of 30% or more, it is possible to suppress the seal strength in the second region R2 of the seal portion 6 from becoming too high. In other words, since the seal strength in the second region R2 can be controlled to a desired value or less, the ease of opening the sterilization packaging material 1 can be improved. In addition, by having a styrene-acrylic compound content of 80% or less, it is possible to suppress a decrease in the heat-sealability of the seal portion 6. The improvement in the ease of opening the sterilization packaging material 1 will be explained in the examples described later.

[0070] In the above-described embodiment, an example was described in which the non-permeable material 20 has a base material 21 including an outer surface 21a and an inner surface 21b, and a sealant layer 22 laminated on the inner surface 21b of the base material 21 and bonded to the permeable material 10, but the invention is not limited to this. For example, the non-permeable material 20 may consist of a single layer or a blister sheet. When the non-permeable material 20 is a single layer, as described above, it is preferable that the non-permeable material 20 (base material 21) also has a sealant function (sealing function).

[0071] Next, the operation of this embodiment described above will be explained in detail.

[0072] (Example 1) Sterilization packaging material as shown in Figure 1 was prepared.

[0073] At this time, a nonwoven fabric made of high-density polyethylene (HDPE) fibers (Tyvek®, 1073B (product name) manufactured by DuPont de Nemours, Inc.) was prepared as the breathable base material for the breathable material.

[0074] Furthermore, a heat sealant containing ethylene-vinyl acetate copolymer (EVA), a styrene-acrylic compound, and an amide compound was prepared as a coating layer for the breathable material. In the heat sealant, the content of ethylene-vinyl acetate copolymer was 43.8%, the content of the styrene-acrylic compound was 53.1%, and the content of the amide compound was 3.1%.

[0075] Next, the heat sealant was diluted with toluene. The heat sealant was diluted so that when its viscosity was measured using a Zahn cup #5, the flow time was approximately 10 to 15 seconds.

[0076] Next, a heat sealant was applied to the entire surface of the nonwoven fabric using a bar coater. Then, the nonwoven fabric coated with the heat sealant was placed in a constant temperature bath set to an internal temperature of 60°C for 30 seconds to dry the heat sealant. The amount of heat sealant applied was 10 g / m². ２ ~12g / m ２ That was the case.

[0077] In this way, a breathable material having a breathable base material (nonwoven fabric) and a coating layer (heat sealant) was obtained.

[0078] Furthermore, a laminate with the following layer structure was prepared as a non-permeable material: PET (thickness 12 μm) / AC / PE (thickness 25 μm) / PE (thickness 25 μm). The " / " indicates the boundary between layers. "PET" refers to polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name E5102). "AC" refers to anchor coating agent (manufactured by Rock Paint Co., Ltd., RAC-420 (main agent) / H-80 (curing agent)). "PE" refers to polyethylene (manufactured by Nippon Polyethylene Co., Ltd., product name LC600A).

[0079] Next, a sterilization packaging material was prepared by heat-sealing a breathable material and a non-breathable material. The heat-sealing conditions were as follows: Equipment: Heat sealer TP-701-A, manufactured by Tester Industries Co., Ltd. Temperature: 150°C, Pressure: 0.5 MPa, Time: 1 second, Sealed area width: 10 mm

[0080] (Example 2) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 23.3% ethylene-vinyl acetate copolymer, 73.0% styrene-acrylic compound, and 3.7% amide compound.

[0081] (Example 3) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 61.4% ethylene-vinyl acetate copolymer, 35.9% styrene-acrylic compound, and 2.7% amide compound.

[0082] (Example 4) A sterilization packaging material was prepared in the same manner as in Example 1, except that a nonwoven fabric made of polypropylene (PP) fibers (manufactured by Maeda Kosen Co., Ltd., Spritop®, SP-1070E (product name)) was used as the breathable base material for the breathable material.

[0083] (Example 5) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 43.8% ethylene-vinyl acetate copolymer, 53.1% styrene-acrylic compound, and 3.1% amide compound, and a single layer resin sheet (250 μm thick) made from amorphous polyethylene terephthalate (A-PET) was used as the non-permeable material.

[0084] (Example 6) A sterilization packaging material was prepared in the same manner as in Example 1, except that a blister sheet (thickness 270 μm) made of polystyrene (PS-TM (product name), manufactured by Towa Gosei Kogyo Co., Ltd.) was used as the non-permeable material.

[0085] (Comparative Example 1) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 15.0% ethylene-vinyl acetate copolymer, 80.8% styrene-acrylic compound, and 4.2% amide compound.

[0086] (Comparative Example 2) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 68.1% ethylene-vinyl acetate copolymer, 29.6% styrene-acrylic compound, and 2.3% amide compound.

[0087] (Comparative Example 3) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 81.7% ethylene-vinyl acetate copolymer and 18.3% styrene-acrylic compound.

[0088] (Comparative Example 4) A sterilization packaging material was prepared in the same manner as in Example 1, except that the heat sealant contained 58.4% ethylene-vinyl acetate copolymer, 38.8% styrene-acrylic compound, and 2.8% amide compound.

[0089] <Seal Strength Measurement Test> Next, the seal strength of the sealed portion of the sterilization packaging materials according to Example 1 to Comparative Example 4 was measured. The seal strength was measured in accordance with JIS Z 0238:1998. The test environment was set to a temperature of 23°C and a relative humidity of 50%.

[0090] In the seal strength measurement test, a test sample was first prepared. The sample was prepared by cutting out the portion containing the seal from the sterilization packaging material. The width of the test sample was 15.0 mm, and the unfolded length was 100 mm. The sample was placed in the test environment for 16 hours before the start of the test.

[0091] Next, the sample was mounted on a pair of grips of a tensile testing machine (Strograph VG1F (product name) manufactured by Toyo Seiki Seisakusho Co., Ltd.) with the sample unfolded 180° in a T-shape. The distance between the grips was set to 50 mm.

[0092] Next, the grips were moved in opposite directions until the seal portion of the sample was completely broken. The relative movement speed of the grips was set to 300 mm / min. The tensile load applied by the grips (N / 15 mm) was defined as the seal strength of the seal portion.

[0093] In this way, the maximum seal strength P1 in the first region R1, the maximum seal strength P2 in the second region R2, and the minimum seal strength B1 in the second region R2 were measured.

[0094] <Openability Evaluation Test> Next, an openability evaluation test was conducted on the sterilization packaging materials according to Example 1 to Comparative Example 4. In the openability evaluation test, 50 pieces of each sterilization packaging material according to Example 1 to Comparative Example 4 were prepared, and all sterilization packaging materials were opened in succession. The ease of opening the sterilization packaging materials was then evaluated.

[0095] The results are shown in Tables 1 and 2, and in Figures 8 to 16. The values ​​in the "Relative Movement Distance (Maximum Value P1) (mm)" column of Table 2 represent the relative movement distance of the grip at the position where the maximum value P1 was achieved. The values ​​in the "Relative Movement Distance (Maximum Value P2) (mm)" column of Table 2 represent the relative movement distance of the grip at the position where the maximum value P2 was achieved. The values ​​in the "Relative Movement Distance (Minimum Value B1) (mm)" column of Table 2 represent the relative movement distance of the grip at the position where the minimum value B1 was achieved. Furthermore, the evaluation criteria for the "Openability" column in Table 2 are as follows: "A" - Opened smoothly. "B" - Felt heavy after starting to open, but was able to open. "C" - Applied further force to the sterilization packaging material after starting to open, causing wrinkles in the sterilization packaging material, making it difficult to open. "-" - Could not heat seal.

[0096]

[0097]

[0098] As a result, as shown in Table 2, the sterilization packaging materials of Comparative Examples 2 to 4 were difficult to open. In Comparative Example 1, the maximum seal strength P1 was 1.10 N / 15 mm. In this case, the breathable material and the non-breathable material were joined to each other at the seal with a seal strength equivalent to temporary adhesion. That is, the seal would peel off with even a small amount of force applied to the seal. For this reason, Comparative Example 1 is marked with a "-" in the "Openability" column as an example of a material that could not be heat-sealed.

[0099] In contrast, the sterilization packaging materials according to Examples 1 to 6 could be opened. In particular, the sterilization packaging materials according to Examples 1, 2, 4, 5, and 6 could be opened smoothly. Therefore, it was found that the sterilization packaging materials according to this embodiment can improve the ease of opening the sterilization packaging materials.

[0100] It is also possible to combine the multiple components disclosed in each of the above embodiments as needed. Alternatively, some components may be removed from all the components shown in each of the above embodiments.

Claims

1. A sterilization packaging material comprising a gas-permeable breathable material and a non-breathable material joined to a part of the breathable material via a sealing portion, wherein the breathable material comprises a breathable substrate and a coating layer applied to the breathable substrate, the coating layer comprises an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the sealing portion, when the sealing strength is measured using a pair of grips in accordance with JIS Z0238:1998, has a maximum sealing strength P1 in a first region where the relative movement distance of the grips is 0 mm or more and 4 mm or less, and has a maximum sealing strength P2 in a second region where the relative movement distance of the grips is 4 mm or more and 17 mm or less, and the maximum sealing strength P2 is 85% or less of the maximum sealing strength P1.

2. The sterilization packaging material according to claim 1, wherein the sealing portion has a minimum value B1 of sealing strength in the second region when the sealing strength is measured using a pair of grips in accordance with JIS Z0238:1998, and the minimum value B1 is 30% or more of the maximum value P1.

3. The sterilization packaging material according to claim 1, wherein the maximum value P1 is 2.0 N / 15 mm or more and 10.0 N / 15 mm or less, and the seal strength in the second region is 0.6 N / 15 mm or more and 8.0 N / 15 mm or less.

4. The sterilization packaging material according to claim 1, wherein the content of the styrene-acrylic compound in the coating layer is 30% or more and 80% or less.

5. The sterilization packaging material according to claim 1, wherein the breathable substrate is composed of high-density polyethylene fibers or polypropylene fibers.

6. The sterilization packaging material according to claim 1, wherein the non-permeable material comprises a base material including an outer surface and an inner surface, and a sealant layer laminated on the inner surface of the base material and bonded to a part of the permeable material.

7. The sterilization packaging material according to claim 1, wherein the non-permeable material consists of a single layer or a blister sheet.

8. A sterilization packaging material comprising a gas-permeable breathable material and a non-breathable material bonded to a part of the breathable material, wherein the breathable material comprises a breathable substrate and a coating layer applied to the breathable substrate, the coating layer contains an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the content of the styrene-acrylic compound in the coating layer is 30% or more and 80% or less.

9. A breathable material having gas permeability, comprising a breathable substrate and a coating layer applied to the breathable substrate, wherein the coating layer contains an ethylene-vinyl acetate copolymer and a styrene-acrylic compound, and the content of the styrene-acrylic compound in the coating layer is 30% or more and 80% or less.

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