Packaging material for sterilization

Abstract

The present invention provides a novel packaging material for sterilization which has processing suitability as a packaging material, is compatible with all sterilization processing methods such as those performed under high-temperature conditions, has small variation in shapes and dimensions, and is capable of maintaining an internal sterilized condition. This packaging material for sterilization is configured from at least two layers of laminated non-woven fabrics comprising a non-woven fabric layer (I) formed of continuous long fibers having an average fiber diameter of 5-30 μm and a non-woven fabric layer (II) formed of ultra-fine fibers having an average fiber diameter of 0.1-4 μm.

Claims

1. A packaging material for sterilization constructed of a layered nonwoven fabric with at least two layers, comprising a nonwoven fabric layer (I) formed of continuous long fibers having an average fiber diameter of 5 to 30 μm and a nonwoven fabric layer (II) formed of ultrafine fibers having an average fiber diameter of 0.1 to 4 μm, wherein the specific surface area of the packaging material is 1.2 to 10 m.sup.2/g, and the apparent density of the packaging material is 0.66 g/cm.sup.3 or less.

2. The packaging material for sterilization according to claim 1, wherein an interlayer formed of the nonwoven fabric layer (II) is disposed between two layers of the nonwoven fabric layer (I).

3. The packaging material for sterilization according to claim 1, wherein the nonwoven fabric layer (II) is composed of a melt-blown nonwoven fabric.

4. The packaging material for sterilization according to claim 1, wherein the average flow pore size of the layered nonwoven fabric is 0.1 to 30 μm, and the bubble point is 0.5 to 50 μm.

5. The packaging material for sterilization according to claim 1, wherein the basis weight of the layered nonwoven fabric is 8.0 to 100 g/m.sup.2, and the thickness is 0.03 to 0.2 mm.

6. The packaging material for sterilization according to claim 1, wherein the air permeability is 1 to 100 seconds/100 ml, as determined by the time required for 100 ml of air to pass through the layered nonwoven fabric in a Gurley air permeability test.

7. The packaging material for sterilization according to claim 1, wherein the tensile strength of the layered nonwoven fabric is 10 to 300 N/25 mm width, and the puncture strength is 70 to 700 N.

8. The packaging material for sterilization according to claim 1, wherein the layered nonwoven fabric is made of polyester.

9. The packaging material for sterilization according to claim 2, wherein the nonwoven fabric layer (II) is composed of a melt-blown nonwoven fabric.

10. The packaging material for sterilization according to claim 2, wherein the average flow pore size of the layered nonwoven fabric is 0.1 to 30 μm, and the bubble point is 0.5 to 50 μm.

11. The packaging material for sterilization according to claim 2, wherein the basis weight of the layered nonwoven fabric is 8.0 to 100 g/m.sup.2, and the thickness is 0.03 to 0.2 mm.

12. The packaging material for sterilization according to claim 2, wherein the air permeability is 1 to 100 seconds/100 ml, as determined by the time required for 100 ml of air to pass through the layered nonwoven fabric in a Gurley air permeability test.

13. The packaging material for sterilization according to claim 2, wherein the tensile strength of the layered nonwoven fabric is 10 to 300 N/25 mm width, and the puncture strength is 70 to 700 N.

14. The packaging material for sterilization according to claim 2, wherein the layered nonwoven fabric is made of polyester.

15. The packaging material for sterilization according to claim 1, wherein the atmospheric dust trapping efficiency is 98.1% to 99.9%.

16. The packaging material for sterilization according to claim 15, wherein the specific surface area of the packaging material is 1.2 to 3 m.sup.2/g.

17. The packaging material for sterilization according to claim 1, wherein the specific surface area of the packaging material is 1.2 to 3 m.sup.2/g.

18. The packaging material for sterilization according to claim 1, wherein the specific surface area of the nonwoven fabric layer (II) is 1.8 to 15.1 m.sup.2/g.

19. The packaging material for sterilization according to claim 15, wherein the specific surface area of the nonwoven fabric layer (II) is 1.8 to 15.1 m.sup.2/g.

Description

EXAMPLES 1 TO 7

(1) Using a polyethylene terephthalate (PET) resin in a spunbond method, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 300° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PET resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The obtained web was then calendered to obtain a packaging material for sterilization.

EXAMPLE 8

(2) Using a PET resin in a spunbond method, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 300° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PET resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin, to produce an SB-MB layered nonwoven fabric. The obtained web was then calendered to obtain a packaging material for sterilization.

EXAMPLES 9 TO 12

(3) Using a polypropylene (PP) resin in a spunbond method, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 230° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PP resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The obtained web was then calendered to obtain a packaging material for sterilization.

EXAMPLE 13

(4) Using a PET resin in a spunbond method, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 300° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PET resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The obtained web was then calendered, and subjected to water repellency treatment by coating with a fluorine-based water-repellent agent by an appropriate method.

EXAMPLE 14

(5) Using a PET resin and a CO-PET resin in a spunbond method, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 300° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed as a two-component fiber nonwoven fabric on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PET resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The obtained web was then calendered to obtain a packaging material for sterilization.

EXAMPLES 15 TO 22

(6) Using a polyethylene terephthalate (PET) resin in a spunbond method, in the same manner as Examples 1 to 7, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 300° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PET resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The conditions for discharge, cooling and trapping during discharge were each set from the viewpoint of minimizing fusion. The obtained web was then subjected to calendering under appropriate conditions using calender rolls with optimized roll hardness, from the viewpoint of maintaining the fiber shapes, to obtain a packaging material for sterilization.

EXAMPLE 23

(7) Using a polypropylene (PP) resin in a spunbond method, in the same manner as Examples 1 to 7, a long fiber group of filaments was extruded toward a moving collection net and spun at a spinning speed of 4500 m/min, at a spinning temperature of 230° C., electrification was carried out at about 3 μC/g by corona electrification to thoroughly open the fibers, and a thermoplastic resin long fiber web was formed on the collection net. The web was blown by the MB method described below onto the previously formed SB nonwoven fabric. Using a PET resin as the fiber material, the molten PET resin was extruded with an extruder from a spinneret nozzle with a spinneret nozzle diameter of 0.30 mm. The PP resin melting temperature, spinning gas temperature and molten resin single-hole throughput in the extruder were appropriately selected for tow thinning of the thermoplastic resin. An SB nonwoven fabric was also blown onto the MB nonwoven fabric in the same manner to produce an SB-MB-SB layered nonwoven fabric. The conditions for discharge, cooling and trapping during discharge were each set from the viewpoint of minimizing fusion. The obtained web was then subjected to calendering under appropriate conditions using calender rolls with optimized roll hardness, from the viewpoint of maintaining the fiber shapes, to obtain a packaging material for sterilization.

COMPARATIVE EXAMPLE 1

(8) A nonwoven fabric (yam diameter: 16 μm, basis weight: 25 g/m.sup.2) made of a PET resin was blown onto a net by an SB method, and thermally bonded with flat rolls at a linear pressure of 260 N/cm and a temperature of 190° C., and then processed with calender rolls at a linear pressure of 294 N/cm and a temperature of 245° C., to obtain a layered nonwoven fabric.

COMPARATIVE EXAMPLE 2

(9) An MB nonwoven fabric (yam diameter: 2 μm, basis weight: 25 g/m.sup.2) made of a PET resin was blown onto a net and thermally bonded with flat rolls at a linear pressure of 260 N/cm and a temperature of 120° C., and then processed with calender rolls at a linear pressure of 340 N/cm and a temperature of 40° C., to obtain a layered nonwoven fabric.

COMPARATIVE EXAMPLE 3

(10) An MB nonwoven fabric (yarn diameter: 1.0 μm, basis weight: 25 g/m.sup.2) made of a PET resin was blown onto a net, and then processed with calender rolls at a linear pressure of 340 N/cm and a temperature of 40° C., to obtain a layered nonwoven fabric.

COMPARATIVE EXAMPLE 4

(11) A packaging material for sterilization composed of a nonwoven fabric formed by a commonly used polyethylene flash spun method (yarn diameter: 5 μm, basis weight: 75 g/m.sup.2).

COMPARATIVE EXAMPLE 5

(12) A packaging material for sterilization composed of a nonwoven fabric formed by a commonly used polyethylene flash spun method (yarn diameter: 4 μm, basis weight: 63 g/m.sup.2).

COMPARATIVE EXAMPLE 6

(13) A sterilized sheet composed of commonly used pulp staple fibers (yarn diameter: 4 μm, basis weight: 63 g/m.sup.2).

(14) The nonwoven fabric structures of Examples 1 to 23 and Comparative Examples 1 to 6, and the specific properties of the obtained nonwoven fabrics, are shown in Tables 1 to 4 below.

(15) TABLE-US-00001 TABLE 1 Layer I Layer II Layer I Prescription Specific Fiber Fiber Fiber Fiber Fiber surface Fiber Fiber Fiber Fiber Melting type diameter amount type diameter area amount type diameter amount point Units μm g/m.sup.2 μm g/m.sup.2 μm g/m.sup.2 ° C. Example 1 PET 12 20 PET 0.3 3.0 10 PET 12 20 260 SB MB SB Example 2 PET 20 20 PET 1.1 1.9 10 PET 20 20 260 SB MB SB Example 3 PET 20 20 PET 2.1 0.9 10 PET 20 20 260 SB MB SB Example 4 PET 20 20 PET 3.1 0.7 10 PET 20 20 260 SB MB SB Example 5 PET 12 35 PET 2.4 0.7 10 PET 12 35 260 SB MB SB Example 6 PET 12 20 PET 2.6 0.6 5 PET 12 20 260 SB MB SB Example 7 PET 12 20 PET 2.2 0.9 30 PET 12 20 260 SB MB SB Example 8 PET 15 20 PET 2.0 1.0 10 — — — — SB MB Example 9 PP 12 20 PP 0.1 8.0 10 PP 12 20 160 SB MB SB Example 10 PP 15 20 PP 1.0 2.8 10 PP 15 20 160 SB MB SB Example 11 PP 15 20 PP 1.2 2.5 10 PP 15 20 160 SB MB SB Example 12 PP 15 20 PP 1.6 2.0 20 PP 15 20 160 SB MB SB Example 13 PET 12 20 PET 2.1 1.6 10 PET 12 20 260 SB MB SB Example 14 Co- 20 20 PET 2.4 1.5 10 PET 15 20 260 PET/PET SB SB SB

(16) TABLE-US-00002 TABLE 2 Prescription Average MD CD flow rate Specific Heat Basis Thick- Void tensile tensile pore Bubble surface shielding weight ness Density % strength strength diameter point area property Units g/m.sup.2 μm g/cm.sup.3 % N/25 mm N/25 mm μm μm m.sup.2/g N/3 cm Example 1 50 0.08 0.66 52 52.2 22.5 1.4 5.4 0.08 32 Example 2 50 0.07 0.71 48 54 23 1.9 8.0 0.04 39 Example 3 51 0.06 0.85 39 73 27 3.4 10.8 0.02 38 Example 4 51 0.06 0.86 38 74 28 4.8 14.7 0.03 41 Example 5 30 0.04 0.76 45 20 45 4.0 9.0 0.03 37 Example 6 60 0.06 1.01 27 87 39 17.4 38.2 0.02 33 Example 7 80 0.08 1.00 27 81 41 2.8 3.0 0.04 31 Example 8 30 0.03 0.99 28 17 39 11.3 23.4 0.04 38 Example 9 45 0.16 0.28 69 12.3 5.8 1.4 10.5 0.09 31 Example 10 51 0.08 0.63 30 14 30 1.2 4.3 0.04 30 Example 11 55 0.10 0.55 39 35 18 2.1 7.3 0.06 32 Example 12 66 0.11 0.60 33 28 15 1.0 0.06 32 Example 13 50 0.06 0.83 40 74 35 2.8 9.0 0.02 36 Example 14 52 0.06 0.87 37 70 30 3.5 20.2 0.02 53 Prescription Gurley Water Cell air MD CD Steam Heat pressure property Atmospheric perme- Puncture tearing tearing perme- shrink- resist- evalu- dust trapping ability strength strength strength ability age ance ation efficiency Units sec N N N g/m.sup.2/24 hr % mmH.sub.2O % Example 1 5 237 17 24 1680 0.6 260 G 95.4 Example 2 3 259 15 22 1700 0.6 310 G 94.3 Example 3 5 257 17 19 1650 0.5 290 G 93.2 Example 4 3 269 13 22 1710 0.5 220 G 92.8 Example 5 3 576 32 31 1730 0.4 1530 G 92.6 Example 6 15 240 13 22 1350 0.3 390 G 90.2 Example 7 27 242 14 29 1230 0.4 500 G 91.8 Example 8 1 174 11 6 1920 0.5 350 G 90.9 Example 9 2 224 21 26 1850 0.6 910 G 95.8 Example 10 11 248 14 30 1410 0.7 610 G 93.9 Example 11 4 268 26 26 1780 0.8 550 G 92.1 Example 12 12 249 23 33 1400 0.9 530 G 94.6 Example 13 7 257 25 19 1660 0.5 710 G 91.4 Example 14 4 360 16 20 1800 0.9 980 G 91.9

(17) TABLE-US-00003 TABLE 3 Layer I Layer II Layer I Prescription Specific Fiber Fiber Fiber Fiber Fiber surface Fiber Fiber Fiber Fiber Melting type diameter amount type diameter area amount type diameter amount point Units μm g/m.sup.2 μm g/m.sup.2 μm g/m.sup.2 ° C. Example 15 PET 12 20 PET 0.3 6.2 10 PET 12 20 260 SB MB SB Example 16 PET 12 20 PET 0.1 12.1 10 PET 12 20 260 SB MB SB Example 17 PET 20 20 PET 1.1 5.8 10 PET 20 20 260 SB MB SB Example 18 PET 20 20 PET 2.1 3.9 10 PET 20 20 260 SB MB SB Example 19 PET 20 20 PET 3.1 2.8 10 PET 20 20 260 SB MB SB Example 20 PET 12 35 PET 2.4 1.8 10 PET 12 35 260 SB MB SB Example 21 PET 12 20 PET 2.6 2.5 5 PET 12 20 260 SB MB SB Example 22 PET 12 20 PET 2.2 2.0 30 PET 12 20 260 SB MB SB Example 23 PP 12 20 PP 0.1 15.1 10 PP 12 20 160 SB MB SB Comp. PET 16 25 — — — — — — — — Example 1 SB Comp. — — — PET 2 1.3 25 — — — — Example 2 MB Comp. — — — PET 1 2.2 25 — — — — Example 3 MB Comp. — — — PE 5 0.8 73.5 — — — — Example 4 Flash- spun Comp. — — — PE 4 1.1 62.5 — — — — Example 5 Flash- spun Comp. — — — Pulp 22 0.5 62.6 — — — — Example 6 staple fibers

(18) TABLE-US-00004 TABLE 4 Perscription Average MD CD flow rate Specific Heat Basis Thick- Void tensile tensile pore Bubble surface shielding weight ness Density % strength strength diameter point area property Unit g/m.sup.2 μm g/cm.sup.3 % N/25 mm N/25 mm μm μm m.sup.2/g N/3 cm Example 15 50 0.08 0.66 52 50.1 23.5 1.3 5.8 1.2 30 Example 16 50 0.08 0.63 55 51.5 25.6 0.6 3.1 2.8 30 Example 17 50 0.07 0.71 48 52 20 1.8 7.8 0.9 41 Example 18 51 0.06 0.85 39 75 24 3.2 11.9 0.5 40 Example 19 51 0.05 1.03 26 78 29 4.2 15.1 0.4 43 Example 20 30 0.05 0.60 56 25 44 3.8 10.5 0.3 40 Example 21 60 0.08 0.75 45 67 42 14.3 35.6 0.4 39 Example 22 80 0.1 0.80 42 84 48 1.9 2.9 0.5 32 Example 23 45 0.16 0.28 69 12.3 5.8 1.4 10.5 3.0 31 Comp. 25 0.04 0.59 57 78 39 35.3 87.8 — 12 Example 1 Comp. 25 0.04 0.66 52 5 2 3.9 9.7 1.3 21 Example 2 Comp. 25 0.04 0.60 57 4 2 1.8 5.9 2.2 29 Example 3 Comp. 74 0.17 0.43 52 239 222 1.9 7.2 0.8 25 Example 4 Comp. 63 0.14 0.45 50 148 229 1.9 7.3 1.1 22 Example 5 Comp. 63 0.09 0.70 — 178 92 2.9 10.5 0.5 28 Example 6 Perscription Gurley MD CD Water Cell Atmospheric air Puncture tearing tearing Steam Heat pressure property dust trapping permeability strength strength strength permeability shrinkage resistance evaluation efficiency Unit sec N N N g/m.sup.2/24 hr % mmH.sub.2O % Example 15 5 241 18 29 1640 0.6 270 G 99.8 Example 16 11 254 19 28 1460 5.0 350 G 99.9 Example 17 4 248 17 25 1740 0.7 320 G 98.1 Example 18 5 261 18 21 1640 0.6 300 G 96.5 Example 19 4 271 18 21 1700 0.7 230 G 95.4 Example 20 5 581 30 35 1720 0.4 1500 G 93.2 Example 21 11 262 15 29 1340 0.3 400 G 94.5 Example 22 22 251 19 38 1130 0.4 510 G 96.8 Example 23 2 224 21 26 1850 0.6 910 G 99.9 Comp. 0.3 119 9 8 2420 0.7 100 P 35.2 Example 1 Comp. 29 11 2 2 340 0.5 70 G 99.8 Example 2 Comp. 35 9 3 2 300 0.6 80 G 99.9 Example 3 Comp. 14.7 568 3 4 1620 7.0 1500 G 99.9 Example 4 Comp. 16.2 341 5 2 1600 7.5 1450 G 99.9 Example 5 Comp. 10.4 53 1 1 530 2.0 340 G 85.4 Example 6

INDUSTRIAL APPLICABILITY

(19) The layered nonwoven fabric of the invention can be suitably used as a packaging material for sterilization in the field of medicine, for the purpose of preventing infectious contamination of sondes, scalpels, pincettes, scissors and the like.