JP2019077465A - Medical packaging material - Google Patents

Abstract

To provide a medical packaging material in which deterioration in stretch breaking strength and appearance change hardly occur even after radiation sterilization treatment, and which has excellent flex pinhole resistance.SOLUTION: A medical packaging material has a laminate structure with a biaxially-stretched polybutylene terephthalate film comprising polybutylene terephthalate resin at least as a layer material, and is used after radiation sterilization treatment is performed. A maintenance factor of stretch breaking strength of the medical packaging material after radiation sterilization treatment with respect to stretch breaking strength before radiation sterilization treatment is equal to or greater than 90%, and the number of pinholes when bending 500 times is equal to or less than 30.SELECTED DRAWING: None

Description

  The present invention relates to a medical packaging material formed by laminating a biaxially stretched polybutylene terephthalate (hereinafter, also described as "OPBT") film as a layer material at least, and in particular, it has tensile strength at break even after radiation sterilization. The present invention relates to a medical packaging material which is resistant to deterioration and appearance change and is excellent in bending pinhole resistance.

Methods of sterilizing medical packaging materials include dry heat sterilization, high pressure steam sterilization and ethylene oxide gas sterilization (EOG sterilization).
However, in the dry heat sterilization method, heat resistance is required for the packaging container because high temperature (140 ° C. or more) and long processing time are required in the oven. Moreover, in the high pressure steam sterilization method, high pressure water is used, so high water resistance is required for the packaging container. Furthermore, ethylene oxide gas sterilization may cause ethylene oxide gas to remain in the packaging container after sterilization, and it has been pointed out that it has an impact on the human body.
Under such circumstances, the radiation sterilization method has the advantage that after storing the contents such as medical instruments in the packaging container, the whole can be irradiated with radiation and the killing effect is large, and the dose can be adjusted according to the purpose And the packaging container does not require high heat resistance and high water resistance. As radiation intended for sterilization, γ-rays, X-rays and electron beams are practical sources of radiation.

  However, in the radiation sterilization method, phenomena such as deterioration of the medical devices and the packaging containers, which are the contents, and coloring are confirmed, and in particular, most of the contents and the packaging containers are made of a polymer material, The polymer was decomposed by the irradiation, and strength reduction, coloring and odor of the packaging container were generated. As the causative substance of odor, most gases generated by decomposition of thermoplastic resin such as polyethylene which becomes the inner surface of the packaging container by irradiation are lower hydrocarbons such as ethane, propane and butane and their derivatives. It is considered to be an aldehyde and a carboxylic acid, and its concentration is low, so it is considered that the influence on hygiene etc. is small, but there is a problem of giving an unpleasant feeling due to odor.

Also, as other polymer materials used as a radiation sterilization packaging material other than polyethylene, for example, polypropylene, polyamide, polyvinyl chloride and the like can be mentioned, and all of them can be colored by irradiation or extremely strong. Is basically not suitable as a packaging material for radiation sterilization.
However, in order to provide practical strength, for example, in a biaxially stretched nylon film of a polyamide type, in order to compensate for the decrease in strength due to irradiation, the film may be used with a large thickness.

  On the other hand, examples of polymer materials with little change in physical properties due to radiation include polyesters such as polyethylene terephthalate, but the pinhole resistance is not sufficient due to the properties of the material, and therefore its use is limited to the contents in the packaging container. There were restrictions in use, such as being limited to cases of light weight.

By the way, as a means to reduce deterioration such as strength reduction and coloring after radiation sterilization treatment of medical devices and the like formed from polymer materials, aliphatics specific to soft vinyl chloride resin compositions used for medical materials Medical vinyl chloride resin obtained by blending 4-cyclohexene-1,2-dicarboxylic acid diester obtained by esterification reaction of a saturated alcohol with 4-cyclohexene-1,2-dicarboxylic acid or its anhydride A material composed of a composition has a low deterioration after sterilization and can be used as a medical material (Patent Document 1), wherein the inside of the permeation device is replaced with an inert gas and then the device is irradiated with gamma rays. Sterilization method (Patent Document 2), and radiation sterilization by sealing so that the atmosphere has an oxygen concentration of 0.5% or more and less than 4%. (Patent Document 3) are disclosed. Also, a packaging material for radiation sterilization is disclosed in which polyethylene terephthalate capable of heat fusion at a temperature range of 80 to 200 ° C. is laminated on a stretched polyethylene terephthalate film (Patent Document 4).

JP, 2016-141712, A Japanese Patent Application Laid-Open No. 59-192373 Japanese Patent Laid-Open No. 3-18371 Japanese Patent Application Laid-Open No. 61-249468

  However, soft vinyl chloride resins do not pose a problem when used in medical devices, but they often lack strength when used in medical packaging materials, and a sufficient pinhole resistance can not be obtained. was there. In the case of irradiating the penetration device with gamma rays in an inert gas atmosphere or irradiating the packaging material with radiation in an atmosphere with an oxygen concentration of 0.5% or more and less than 4%, large-scale equipment is provided in the irradiation chamber. It was necessary and there were restrictions in terms of equipment. Furthermore, the strength of the packaging material for radiation sterilization, which is formed by laminating polyethylene terephthalate that can be heat-fused at a temperature range of 80 to 200 ° C. on drawn polyethylene terephthalate, is about the same as the strength of drawn polyethylene terephthalate. There was a problem that pinhole property could not be obtained.

  The present inventors employ a configuration in which an OPBT film made of polybutylene terephthalate resin is laminated at least as a layer material in a medical packaging material, so that pinhole resistance is good and strength after radiation sterilization processing The inventors have found that it is difficult to reduce physical properties and coloring, and that excellent performance as a medical packaging material can be secured, and the present invention has been completed.

That is, the present invention provides the following.
[1] A medical packaging material to be used after being subjected to radiation sterilization, which is formed by laminating a biaxially stretched polybutylene terephthalate film consisting of polybutylene terephthalate resin as at least a layer material, and the radiation sterilization of the medical packaging material The medical package characterized in that the maintenance rate for tensile breaking strength before radiation sterilization is 90% or more, and the number of pinholes after bending 500 times is 30 or less. Material.
[2] The medical use as described in [1], wherein the biaxially stretched polybutylene terephthalate film laminated and configured in order of the base material layer and the sealant layer from the outside is used for the base material layer. Packaging material.
[3] The medical packaging material according to [1] or [2], wherein the radiation is a γ ray or an electron beam.
[4] The medical packaging material according to [3], wherein the dose of the γ-ray is 5 to 60 kGy.
[5] The medical packaging material according to [3], wherein the dose of the electron beam is 20 to 100 kGy.

  According to the present invention, it has become possible to obtain a medical packaging material excellent in bending pinhole resistance, which is less likely to deteriorate in strength and to be colored even after radiation sterilization.

FIG. 1 is a schematic view of a tubular method simultaneous biaxial stretching apparatus.

Below, the form for implementing this invention is demonstrated concretely.
(Raw material of OPBT film)
The raw material used for the OPBT film is not particularly limited as long as it is a polyester having butylene terephthalate as a main repeating unit, but specifically, 1,4-butanediol as a glycol component, or an ester-forming derivative thereof And terephthalic acid as a dibasic acid component, or an ester-forming derivative thereof as a main component, which is a homo- or copolymer-type polyester obtained by condensation of them. In order to provide optimum mechanical strength properties, melting point 200 to 250 ° C., IV value 1.10 to 1.35 dl / g range among polybutylene terephthalate (hereinafter also described as “PBT”) resin Those having a melting point of 215 to 225 ° C. and an IV value of 1.15 to 1.30 dl / g are particularly preferable.

  In the PBT resin used in the present invention, if necessary, a lubricant, an antiblocking agent, an inorganic extender, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a plasticizer, a colorant, crystallization Additives such as inhibitors and crystallization accelerators may be added. Moreover, in order to avoid the viscosity fall by hydrolysis at the time of heat melting, the polyester resin pellet to be used is sufficiently predried so that the moisture content is 0.05 mass% or less, preferably 0.01 mass% or less before heat melting. It is preferable to use it after carrying out.

(Production method of PBT unstretched raw fabric)
In order to stably produce the OPBT film, it is necessary to minimize the crystallization of the unstretched unstretched film before stretching as much as possible, and when the extruded polybutylene terephthalate melt is cooled to form a film, The crystallization temperature range is cooled at a certain rate or more, that is, the raw cooling rate is an important factor. The raw film cooling rate is 200 ° C./s or more, preferably 250 ° C./s or more, particularly preferably 350 ° C./s or more, and the unstretched raw film formed at a high cooling rate maintains an extremely low crystalline state. Thus, the stability of the bubble at the time of stretching is dramatically improved. Further, since film formation at high speed is also possible, productivity is also improved. If the cooling rate is less than 200 ° C./sec, not only the crystallinity of the obtained unstretched raw fabric may be high and the stretchability may be lowered, but in an extreme case, the stretch bubble is ruptured and the stretch is not continued There is a case.

  The raw film forming method is not particularly limited as long as it can satisfy the raw material cooling rate, but the direct water cooling method inside and outside is most suitable in terms of rapid film formation. The outline | summary of the raw film forming method by the inside and the outside direct water cooling system is demonstrated below. First, the PBT resin is melt-kneaded by an extruder set at a temperature of 210 to 280 ° C., and in the case of T-die film formation, the sheet-like molten resin is immersed in a water tank to directly water cool both inside and outside. On the other hand, in the case of annular film formation, it is extruded downward from an annular die attached downward to the extruder to form a molten tubular thin film.

  Next, it is led to a cooling mandrel connected to an annular die, and the cooling water introduced from each nozzle of the cooling mandrel is cooled by direct contact with the inside of the molten tubular thin film. At the same time, cooling water also flows from the external cooling tank used in combination with the cooling mandrel, and the cooling water is also brought into direct contact with the outside of the molten tubular thin film for cooling. The temperature of the internal water and the external water is preferably 30 ° C. or less, and particularly preferably 20 ° C. or less from the viewpoint of rapid quenching film formation. When the temperature is higher than 30 ° C., the appearance of the raw fabric may be deteriorated due to the whitening of the raw fabric and the boiling of the cooling water, and the drawing may be gradually difficult.

(Method of manufacturing OPBT film)
The PBT unstretched raw fabric needs to be transported to the stretching zone while maintaining the atmosphere temperature at 25 ° C. or less, preferably 20 ° C. or less, and under the temperature control, the unstretched raw fabric immediately after film formation regardless of the residence time. Can maintain its crystallinity. This crystallization control to the stretching start point can be said to be an important point in stably performing biaxial stretching of the PBT resin together with the film forming technology of the unstretched raw fabric.

  The biaxial stretching method is not particularly limited, and may be appropriately selected from, for example, a tubular system, or a method of stretching in the longitudinal and transverse directions simultaneously or sequentially in a tenter system, or the like. From the viewpoint of the balance of physical properties in the circumferential direction of the obtained OPBT film, the simultaneous biaxial stretching method by the tubular method is particularly preferable. FIG. 1 is a schematic view of a tubular method simultaneous biaxial stretching apparatus. The unstretched original fabric 1 guided to the stretching zone is heated between the pair of nip rolls 2 while being heated by the heater 3 while pressing air into the inside, and blowing air from the cooling ring 4 at the stretching end point. As a result, MD and TD simultaneous biaxially stretched films 7 by the tubular method are obtained. The stretching ratio is preferably in the range of 2.7 to 4.5 times each of MD and TD, in consideration of stretching stability and strength properties, transparency and thickness uniformity of the obtained OPBT film. If the draw ratio is less than 2.7 times, the tensile strength and impact strength of the obtained OPBT film may be insufficient, which is not preferable. Further, if it is more than 4.5 times, excessive strain of molecular chain is generated by stretching, so breakage and puncture frequently occur at the time of stretching, and stable production may not be possible. The stretching temperature is preferably in the range of 40 to 80 ° C., particularly preferably 45 to 65 ° C. The unstretched raw fabric produced at the above-mentioned high cooling rate has low crystallinity, so it can be stably stretched at a stretching temperature in a relatively low temperature range. In the case of high-temperature drawing exceeding 80 ° C., the fluctuation of the drawing bubble becomes severe, and large drawing unevenness may occur, so that a film with a good thickness accuracy may not be obtained. On the other hand, at a stretching temperature of less than 40 ° C., excessive stretch orientation crystallization occurs due to low temperature stretching to cause whitening of the film and the like, and in some cases, the stretch bubble may be ruptured to make stretching difficult. By subjecting the film to biaxial stretching in this manner, it is possible to obtain an OPBT film in which particularly the strength properties are dramatically improved and the anisotropy is small.

  Thermal dimensional stability by introducing the obtained OPBT film into a heat roll system or a tenter system, or a heat treatment facility combining them for an arbitrary time and performing heat treatment at 180 to 240 ° C., particularly preferably 190 to 210 ° C. It is possible to obtain an excellent OPBT film. When the heat treatment temperature is higher than 240 ° C., the bowing phenomenon becomes too large, the anisotropy in the width direction increases, or the degree of crystallization becomes too high, so that the strength property may be deteriorated. On the other hand, when the heat treatment temperature is lower than 180 ° C., the thermal dimensional stability of the film is greatly reduced, so that the film is easily shrunk during lamination and printing, which may cause a practical problem.

  The thickness of the OPBT film is 5 to 100 μm, more preferably 10 to 30 μm, when used as a main base material of a medical packaging material. When the thickness is less than 5 μm, the bending pinhole resistance and impact resistance of the packaging material become low, and the bag is easily broken. Similarly, if it is too thick, the bending pinhole resistance may deteriorate.

The tensile strength at break in four directions (0 ° (MD), 45 °, 90 ° (TD), 135 °) of the OPBT film is preferably 170 MPa or more in any case, whereby the impact resistance, the bending resistance, Resistance to puncture, secondary processing suitability, etc. are greatly improved. If the tensile strength at break is less than 170 MPa, it is not preferable because it causes breakage and the like. Furthermore, in order to reduce the anisotropy, the ratio of the maximum value to the minimum value among the tensile breaking strengths in four directions (0 ° (MD), 45 °, 90 ° (TD), 135 °) is 1. Adjustment to 5 or less is preferable, and particularly preferably 1.3 or less. On the other hand, the tensile elongation at break is 50% or more and 150% or less, preferably 100% or more and 150% or less. If it is more than 150% or less than 50%, fracture or elongation of the OPBT film is likely to occur due to the tension when the printing layer is provided on the OPBT film or when the OPBT film is bonded to another substrate. Not desirable. An OPBT film having such characteristics is stably obtained by the above-described manufacturing method.

  In the present invention, when the radiation sterilization treatment is γ-ray sterilization treatment, the dose of γ-ray is preferably 5 to 60 kGy, more preferably 10 to 50 kGy, and particularly preferably 25 to 50 kGy. It is not preferable that the dose of γ-rays is less than 5 kGy because the objective sterilization may become insufficient. If it exceeds 60 kGy, the thermoplastic resin such as polyethylene, which is the inner surface of the packaging material, is decomposed by radiation, and the gas concentration generated thereby is increased, which may unfavorably cause the odor upon opening.

  In the present invention, when the radiation sterilization treatment is electron beam sterilization treatment, the dose of the electron beam is preferably 20 to 100 kGy, and more preferably 25 to 75 kGy. If it is less than 20 kGy, it is not preferable because the objective sterilization may become insufficient. If it exceeds 100 kGy, the thermoplastic resin such as polyethylene, which is the inner surface of the packaging material, is decomposed by radiation, and the gas concentration generated thereby is increased, which may unfavorably cause the odor at the time of opening.

(Composition of medical packaging material)
The medical packaging material in which the OPBT film of the present invention is laminated as at least a layer material may be formed by laminating one or more layers on any one surface of the OPBT film. Specifically, a medical packaging material in which a base material layer and a sealant layer are laminated in this order from the outside can be mentioned, but if necessary, a barrier layer can be provided on the base material layer.
The base material layer can also be configured by using OPBT film alone or in combination with other base materials such as OPBT film and biaxially stretched nylon (hereinafter, ONy) film, biaxially stretched polyethylene terephthalate (hereinafter, OPET) film, and the like.
The barrier layer is vapor deposited on at least one surface of the base layer from aluminum oxide, silicon oxide, titanium oxide, tin oxide, tin oxide, zinc oxide, magnesium oxide, inorganic oxide such as calcium oxide, or aluminum, or a mixture thereof. It can be formed by a method of providing a film. It is preferable to use aluminum oxide or silicon oxide as the vapor deposition film. The vapor deposition film may be formed by physical vapor deposition such as vacuum deposition, sputtering or ion plating, or chemical chemistry such as plasma chemical vapor deposition, thermal chemical vapor deposition or photochemical vapor deposition. Although vapor phase growth can be used, vacuum deposition is particularly preferably used in terms of productivity and cost. Further, it is also preferable to provide a barrier layer by providing a coating layer made of a barrier resin such as polyvinylidene chloride (hereinafter referred to as K coat) on at least one surface of the OPBT film of the base material layer.
The sealant layer is a dry laminating method using an adhesive for lamination to an unstretched polyethylene film, an unstretched polypropylene film, an unstretched polyvinyl chloride film, an ethylene-vinyl acetate film, an ionomer film, and other ethylene copolymer films. It can be formed using a method of laminating by a sandwich laminating method via a heat adhesive resin, an extrusion laminating method of forming a melt extrusion, or a method of coating a hot melt adhesive or the like.

In the present invention, the tensile breaking strength of the medical packaging material after radiation sterilization is 90% or more of the tensile breaking strength before the radiation sterilization. If the maintenance rate for the tensile strength at break before radiation sterilization is less than 90%, there is a possibility that film breakage may occur from the end of the seal when the medical packaging material falls during transportation or storage, etc. There is a possibility of losing product value.
In addition, about the tensile breaking strength after a radiation sterilization process, the maintenance factor with respect to the tensile breaking strength before a radiation sterilization process can be calculated based on a following formula.
Maintenance ratio of tensile strength at break after radiation sterilization (%) = (tensile strength at break after radiation sterilization) / (tensile strength at break before radiation sterilization) × 100

  In the obtained medical packaging material, the number of pinholes when bent 500 times under a condition of 5 ° C. × 40% RH is 30 or less, preferably 20 or less, and 15 or less. Is more preferable, and 10 or less is particularly preferable. When the number of pinholes is more than 30, there is a high probability that cracks or pinholes will occur during transportation or storage, etc., and bacteria will enter from the pinholes to propagate bacteria, losing commercial value. There is a risk of By using the above-mentioned OPBT film as a base material layer, the fall of the intensity physical property after irradiation does not occur easily, and the packing material which is excellent in pinhole resistance is obtained.

  EXAMPLES The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to the following examples.

Example 1 (Production Method of OPBT Film)
PBT resin pellets (homotype, melting point = 224 ° C, IV value = 1.26 dl / g) dried in a hot air dryer at 140 ° C for 5 hours are melted in the extruder at cylinder and die temperatures of 210 to 275 ° C. After kneading, the molten tubular thin film was pushed downward from the annular die. Subsequently, the outer diameter of the cooling mandrel was passed through and folded by a guide roll, and then film formation was carried out at a speed of 1.2 m / min by a take-up nip roll. The temperature of the cooling water in direct contact with the molten tubular thin film was 20 ° C. both inside and outside, and the raw film cooling rate was 416 ° C./sec. The thickness of the unstretched raw fabric is 185 μm, the folding diameter is 143 mm, and 1000 ppm of magnesium stearate as a lubricant is added to the PBT resin in advance. The unstretched raw film 1 formed into a film under the above conditions was conveyed to the nip roll 2 in an atmosphere of 20 ° C., and subjected to longitudinal and biaxial simultaneous biaxial stretching by the tubular method simultaneous biaxial stretching device having the structure shown in FIG. The draw ratio was 3.2 times for MD and 3.2 times for TD, and the drawing temperature was 60.degree. Next, this biaxially stretched film 7 was put into a heat roll type heat treatment facility and then into a tenter type heat treatment facility, and heat treated at 210 ° C. to obtain an OPBT film. In addition, the thickness of the film was 15 micrometers.

(Production method of medical packaging material)
One side of the obtained film is subjected to corona treatment, and an adhesive (dry coating amount: 4.0 g / m ² ) for polyurethane dry lamination is coated on the OPBT film on the corona-treated side by a dry lamination method, and the thickness is After bonding with a 50 μm linear low density polyethylene film (manufactured by Tohcel Co., Ltd., TUX-FCS), aging was carried out at 40 ° C. for 2 days to obtain a medical packaging material.

(Γ-ray sterilization process)
According to the above-mentioned procedure, three medical packaging materials are prepared, and at Japan Radiation Service Co., Ltd., γ rays are applied so that the average absorbed dose to these medical packaging materials is 10, 25 and 50 kGy, respectively. Irradiated.

(Electron beam sterilization process)
According to the above-mentioned procedure, three medical packaging materials are prepared, and at Nippon Irradiation Service Co., Ltd., electron beams are applied so that the average absorbed dose for these medical packaging materials is 25, 50 and 75 kGy, respectively. Irradiated.

(Evaluation method of tensile strength at break)
The tensile breaking strength of the medical packaging material before and after γ-ray irradiation or electron beam irradiation is measured using a Tensilon universal tester (model: RTC-1210-A) manufactured by ORIENTEC Co., Ltd. Sample width 15 mm, chuck interval 100 mm The tensile rupture strength in each direction was determined by performing measurement in each of the MD direction and the TD direction under a condition of a tensile speed of 200 mm / min. The maintenance rates of the tensile fracture strength in the MD direction and the TD direction were determined from the tensile fracture strength before and after irradiation, the average value was calculated, and the determination was made as follows.
Judgment criteria ○: Maintenance rate is 90% or more Δ: Maintenance rate is less than 90% to 70% or more ×: Maintenance rate is less than 70%

(Appearance change judgment)
Twenty sheets of the medical packaging material obtained by the γ-ray irradiation or the electron beam irradiation were stacked and checked visually for yellowing and other abnormalities.
○: Almost no change is seen.
Fair: yellowing can be confirmed.

(Evaluation method of bending resistance to pinholes)
Medical packaging material obtained by γ-irradiation or electron beam irradiation is sampled to A4 size, and 4 under 5 ° C. × 40% RH conditions using a Gelboflex tester (manufactured by Tester Sangyo Co., Ltd.) The pinhole number at the time of bending 500 times was measured about each sample, and the average value was described in Table 1. The test speed was 42 times of reciprocation / minute, the stroke distance was 152.4 mm, and the twist angle was 440 °.

Example 2
The same procedure as in Example 1 was repeated except that the thickness of the base material layer was changed to the thickness described in Table 1 in Example 1.

<Comparative Examples 1 to 3>
The base material was changed to the base material and thickness which were described in Table 1, and various evaluation was performed. As the ONy film, BN-RX (manufactured by Kojin Co., Ltd., thickness 15 μm and 25 μm) was used, and as the OPET film, E5100 (manufactured by Toyobo Co., Ltd., thickness 16 μm) was used.

  As shown in Table 1, in the medical packaging material, by adopting a configuration in which an OPBT film made of polybutylene terephthalate resin is laminated at least as a layer material, bending pinhole resistance is good, and even after radiation sterilization treatment It has been found that it is possible to obtain a packaging material having excellent performance as a medical packaging material, in which the reduction of the strength physical properties and the change in appearance do not easily occur.

The medical packaging material in which the OPBT film of the present invention is laminated as at least a layer material has good resistance to flexing pinholes and tensile strength after radiation sterilization. It is a packaging material which can be used for the packaging bag.

1 Unstretched raw material 2 Nip roll 3 Heater 4 Cooling ring 5 Guide roll 6 Nip roll 7 Biaxially stretched film

Claims (5)

  A medical packaging material to be used after being subjected to radiation sterilization, which is formed by laminating a biaxially stretched polybutylene terephthalate film consisting of polybutylene terephthalate resin as at least a layer material, which is after the radiation sterilization of the medical packaging material What is claimed is: 1. A medical packaging material characterized in that the maintenance ratio for tensile breaking strength before radiation sterilization processing is 90% or more and the number of pinholes when bending 500 times is 30 or less.   The medical packaging material according to claim 1, wherein the biaxially stretched polybutylene terephthalate film laminated and configured in order of the base material layer and the sealant layer from the outside is used for the base material layer.   The medical packaging material according to claim 1 or 2, wherein the radiation is a γ ray or an electron beam.   The medical packaging material according to claim 3, wherein the dose of the γ ray is 5 to 60 kGy.   The medical packaging material according to claim 3, wherein a dose of the electron beam is 20 to 100 kGy.

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