JP2012192038A - Medical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical film having excellent slidability and not causing deterioration of a medicine.SOLUTION: The medical film is characterized in that flaked graphite is contained in a polyethylene-based resin, thereby has the excellent slidability, electroconductivity, and heat-sealing property, and can be easily machined to various kinds of medical applications. Further, the medical film has excellent transparency, and thereby the condition of the medicine housed inside of a packaging bag of the medicine can be easily visually confirmed in the case of using the same to the packaging bag of the medicine.

Description

  The present invention relates to a medical film.

  Conventionally, a liquid medicine used for infusion or the like is stored after being filled in a packaging bag formed of a synthetic resin film. Therefore, it is required that the medicine stored in the packaging bag is not altered by the synthetic resin film constituting the packaging bag.

  Further, the medicine packaging bag is formed by, for example, heat-sealing by folding a flat rectangular synthetic resin film in half and heating the outer peripheral edge of each side. The packaging bag is manufactured as described above while continuously unwinding the synthetic resin film. However, if the synthetic resin film has poor slipperiness, the synthetic resin film and the parts such as a roll constituting the manufacturing apparatus As a result, the synthetic resin film may stay in the manufacturing apparatus and cause a manufacturing trouble.

  Thus, Patent Document 1 discloses a thermoplastic polymer film in which crushed silica particles and spherical organic polymer particles are contained in the thermoplastic polymer film.

  This thermoplastic polymer film contains two types of silica particles. When the silica particles form irregularities on the surface of the thermoplastic resin polymer film and overlap the films, the contact area between the films is reduced. To improve the slipperiness.

  However, since the thermoplastic polymer film contains crushed silica particles, the tip of the convex portion formed on the surface of the thermoplastic polymer film may be slightly sharpened, and as a result. Further, the convex portions of the thermoplastic polymer film may be caught with each other, which may cause a problem that the slipping property of the thermoplastic polymer film is lowered.

JP-A-9-241521

  The present invention provides a medical film that has excellent slipperiness and does not cause alteration of a drug.

  The medical film of the present invention is characterized in that exfoliated graphite is contained in a polyethylene resin.

  The polyethylene resin constituting the medical film is not particularly limited, and for example, a low density polyethylene resin, a medium density polyethylene resin, a high density polyethylene resin, a linear low density polyethylene resin, a linear Examples thereof include medium density polyethylene resins and linear high density polyethylene resins, and linear low density polyethylene is preferable. The polyethylene resin may be used alone or in combination.

  The polyethylene resin contains exfoliated graphite. This exfoliated graphite is a laminate of a plurality of graphene sheets. Exfoliated graphite is obtained by exfoliating a graphite compound, and is a laminate of graphene sheets having a thickness smaller than that of a raw material graphite compound, that is, less than the number of laminated graphene sheets of a raw material graphite compound. It is the laminated body of the graphene sheet which has a lamination | stacking number. In the present invention, the graphene sheet refers to a single sheet-like material composed of a carbon hexagonal mesh plane.

  The graphite compound may be either graphite or expanded graphite, but expanded graphite is preferred because it is easily peeled from between the graphene sheets. Note that a functional group may be chemically bonded to graphite, or a functional group may be artificially bonded to graphite due to weak interaction. In the present invention, expanded graphite refers to a material in which an interlayer material is inserted into a raw material graphite and a space between graphene sheets is widened.

  The number of graphene sheets laminated in exfoliated graphite may be 2 to 200 layers as long as it is less than the number of laminated graphite compounds as raw materials. Exfoliated graphite has a scaly shape in which a plurality of thin graphene sheets are laminated and has a relatively large aspect ratio.

  The number of graphene sheets laminated in exfoliated graphite is preferably 150 layers or less, more preferably 60 layers or less, still more preferably 30 layers or less, particularly preferably 10 layers or less, and most preferably 5 layers or less. In addition, the number of graphene sheets stacked in exfoliated graphite can be measured using a transmission electron microscope (TEM), and is an arithmetic average value of the number of graphene sheets stacked in each exfoliated graphite.

  Further, the aspect ratio of exfoliated graphite is preferably 20 or more, more preferably 50 or more, particularly preferably 100 or more, and most preferably 200 or more, but if it is too high, cracking of exfoliated graphite may occur. 5000 or less is preferable. The aspect ratio of exfoliated graphite refers to the arithmetic average value of the aspect ratios of each exfoliated graphite by calculating the aspect ratio obtained by dividing the maximum dimension in the plane direction of the graphene sheet by the thickness for each exfoliated graphite.

  Here, the maximum dimension of the exfoliated graphite in the plane direction of the graphene sheet refers to the maximum dimension of the exfoliated graphite when viewed from the direction in which the area of the exfoliated graphite is the largest. The thickness of exfoliated graphite refers to the maximum dimension of exfoliated graphite in the direction orthogonal to the surface of exfoliated graphite when viewed from the direction in which the area of exfoliated graphite is the largest.

  In addition, the maximum dimension in the surface direction of a graphene sheet in exfoliated graphite can be measured using FE-SEM. Moreover, the thickness of exfoliated graphite can be measured using a transmission electron microscope (TEM) or FE-SEM.

  When the content of exfoliated graphite in the medical film is small, the unevenness formed on the surface of the medical film becomes insufficient, and the slipperiness of the medical film may be lowered. Therefore, 0.005 to 2% by weight is preferable, and 0.01 to 0.5% by weight is more preferable.

  The medical film of the present invention does not contain any additives other than exfoliated graphite so that the drug in contact with the medical film does not deteriorate. Therefore, the remaining part except exfoliated graphite in a medical film is comprised from the polyethylene-type resin. Accordingly, the content of the polyethylene resin in the medical film is preferably 98 to 99.995% by weight, and more preferably 99.5 to 99.99% by weight. Examples of the additive include an antioxidant, a light stabilizer, an ultraviolet absorber, a lubricant, an antiblocking agent, and an antistatic agent.

  As described above, exfoliated graphite is obtained by exfoliating a graphite compound, and has a scaly shape with a relatively large aspect ratio. Most of exfoliated graphite is the main component of graphene sheets. It is contained in a state where the surface is aligned with the front and back surfaces of the medical film, and the top of the convex portion formed by exfoliated graphite on the surface of the medical film is not sharp, as shown in FIG. As described above, a part of exfoliated graphite is contained in the polyethylene-based resin in a state of protruding from the surface A1 of the medical film A with its main surface facing the surface of the medical film A, and for medical use. On the surface A1 of the film A, convex portions A2 having a substantially trapezoidal cross section are formed in a state of being scattered substantially uniformly. In addition, the main surface of a graphene sheet means a surface with the largest area.

  Therefore, when the medical films A and A rub against each other, the convex portions A2 and A2 formed on the surface A1 of the medical films A and A are not caught, and the medical films A and A Are rubbed smoothly, and the medical film A has excellent slipperiness.

  Furthermore, since exfoliated graphite has a large specific surface area, the main surface is oriented along the front and back surfaces of the medical film, and gentle irregularities are easily formed on the surface of the medical film A by exfoliated graphite. In addition, the content of exfoliated graphite necessary for expressing excellent slipperiness in the medical film A can be kept low, and the medical film of the present invention has excellent transparency, and the medical film Visibility of the medicine coated with can be ensured.

  And since exfoliated graphite is a laminate of a plurality of graphene sheets, unlike an additive made of an organic compound or the like, the exfoliated graphite does not alter the drug that comes into contact with the medical film, and Since it is harmless, there is no problem in terms of patient health.

  The medical film may be laminated and integrated on the surface with a cloth-like body such as a nonwoven fabric, a woven fabric, or a knitted fabric, another thermoplastic resin film, and a metal foil.

  Next, a method for producing exfoliated graphite contained in a medical film will be described. Exfoliated graphite is produced by exfoliating a graphite compound, and the method for producing exfoliated graphite is not particularly limited, but exfoliated graphite is preferably produced by the following method.

  First, a graphite sheet or an expanded graphite sheet is used as a working electrode, and the working electrode is immersed in an acidic electrolyte aqueous solution together with a reference electrode made of Pt or the like and subjected to electrochemical treatment. Thereby, an acidic electrolyte ion can be intercalated between graphite sheets, that is, graphene sheets of layered graphite, and the interval between the graphene sheets can be widened.

  Specifically, as shown in FIG. 2, a sheet 1 made of graphite or expanded graphite is prepared. A plurality of slits 1a and 1b are formed in the sheet 1 as shown in FIG. The sheet 1 is a laminate of a plurality of graphene sheets G as schematically shown. The plurality of slits 1a and 1b penetrating in the thickness direction of the sheet 1 which is perpendicular to the surface direction of the graphene sheet G are formed. The slits 1a and 1b can be formed by mechanical cutting or laser light irradiation. The number of slits is not particularly limited.

  Next, part of the electrode 2 is inserted into the slits 1a and 1b. The electrode 2 includes insertion pieces 2a and 2b that are inserted into the slits 1a and 1b, respectively, and a connecting portion 2c that connects the insertion pieces 2a and 2b. The electrode 2 is made of Pt in the present embodiment, but can be formed of an appropriate metal.

  Insert pieces 2a and 2b of the electrode 2 are inserted into the slits 1a and 1b. As a result, a structure in which a part of the electrode 2 is inserted into the sheet 1 as shown in FIG. 3 can be obtained. This structure is immersed in an aqueous electrolyte solution as shown in FIG.

  As the electrolyte solution 6, an aqueous nitric acid solution, an aqueous sulfuric acid solution, or the like can be used. Thereby, nitrate ions or sulfate ions can be inserted between the graphene sheets.

  The sheet 1 immersed in the electrolyte solution 6 is used as a working electrode, and a counter electrode 7 made of a metal such as Pt and a reference electrode 8 made of Ag / AgCl are immersed in the electrolyte solution 6. Electrochemical treatment is performed with a DC voltage applied between them. As a result, the electrolyte ions in the electrolyte solution 6 are intercalated between the graphene sheets of the sheet 1. In addition, a gap between the graphene sheets of the sheet 1 is widened.

  In the electrochemical treatment, a DC voltage of preferably 0.3 to 10 V is applied between the counter electrode 7 and the sheet 1 for 1 hour or more and less than 500 hours. If the DC voltage range is within this range, electrolyte ions such as nitrate ions and sulfate ions can be more reliably intercalated between graphene sheets of graphite compounds, and expanded graphite can be obtained more reliably. Can do. The DC voltage application time may be one hour or longer, but if it is too long, the productivity of expanded graphite is reduced and the effect of intercalating electrolyte ions is saturated. Therefore, the DC voltage application time may be less than 500 hours.

  The concentration of the electrolyte solution 6 is not particularly limited, but is preferably 10 to 80% by weight in the case of an aqueous solution. Within this range, electrolyte ions can be intercalated between the graphene sheets more reliably.

  The temperature of the electrolyte solution 6 during the electrochemical treatment is not particularly limited, but in the case of an aqueous solution, the temperature may be about 5 to 100 ° C.

  More preferably, prior to forming the slits 1a and 1b in the sheet 1 made of a graphite compound, it is preferable to prepare a sheet 1 having a lower density. In order to prepare such a sheet 1 having a lower density, for example, the following method can be used. First, a raw material powder of a graphite compound is preliminarily formed into a sheet to obtain a pre-formed sheet. As shown in FIG. 5, the preformed sheet 11 is supplied between the rolls 12 and 13 and rolled. Thereby, a sheet 1 thinner than the preformed sheet 11 can be obtained. In this case, the density of the sheet 1 can be adjusted by adjusting the rolling ratio. That is, by reducing the rolling ratio, a sheet-like graphite compound having a relatively low density can be obtained.

  As described above, when the sheet 1 made of a graphite compound and having a low density is used, the electrolyte ions as the interlayer material are uniformly intercalated between the graphene sheets of the graphite compound, and the interlayer between the graphenes is more reliably expanded. be able to.

  The expanded graphite obtained as described above has a uniform angle between the main surfaces of the graphene sheets by intercalating nitrate ions and the like, and a uniform amount of intercalation between the graphene sheets. Are better. Therefore, the graphene sheets of expanded graphite can be easily separated from each other by applying a peeling force to the obtained expanded graphite. When there is a variation in the amount of intercalation material inserted between the graphene sheets of expanded graphite, there is a portion where the graphene sheets cannot be peeled apart, particularly when a peeling force by heat is applied. On the other hand, the expanded graphite obtained as described above is excellent in the uniformity of the amount of intercalation material inserted between the graphene sheets, so that a peeling force for peeling the graphene sheets was applied. In this case, the graphene sheet can be reliably peeled off from other graphene sheets between almost all graphene sheets. Therefore, exfoliated graphite can be easily obtained by applying a peeling force for peeling the graphene sheets to the expanded graphite obtained by the above manufacturing method.

  The exfoliation process for obtaining exfoliated graphite from expanded graphite can be performed by performing a kind of energy application process selected from the group consisting of heating, mechanical exfoliation force, ultrasonic waves, and the like.

  As an example, exfoliated graphite can be obtained from expanded graphite by heating expanded graphite to 300 to 1200 ° C., preferably 300 to 600 ° C.

  Next, the manufacturing method of the medical film of this invention is demonstrated. As a method for producing a medical film, a known method is used. For example, (1) a polyethylene resin and exfoliated graphite are supplied to an extruder, melt-kneaded, and a cylindrical die is attached to the tip of the extruder. The cylindrical body is extruded, compressed air is sent from the center of the cylindrical body to expand it to a certain size, and cooled by blowing cooling air to the outer surface of the cylindrical body, and then the cylindrical body is cut from a predetermined location. (2) Supplying polyethylene-based resin and exfoliated graphite to an extruder, melt-kneading, and extruding from a T-die attached to the tip of the extruder Examples include the T-die method for producing medical films.

  When manufacturing a medical film as described above, exfoliated graphite is subjected to a shearing force in the extrusion direction when passing through a circular die or a T-die, and the main surface of the graphene sheet faces the surface of the medical film Oriented. Therefore, the obtained medical film A contains exfoliated graphite in a state where the main surface of the graphene sheet is substantially along the surface A1 of the medical film A, and a part of the exfoliated graphite is medical. Projecting on the surface A1 of the medical film A, the surface A1 of the medical film A is formed with convex portions A2 having a substantially trapezoidal cross section in a substantially uniformly dispersed state.

  In addition, although the case where exfoliated graphite was supplied to the extruder was described above, expanded graphite was supplied to the extruder instead of exfoliated graphite or together with exfoliated graphite, and the peeling force applied to the expanded graphite in the extruder. And exfoliating the graphene sheets of expanded graphite to produce exfoliated graphite in an extruder, and extruding the exfoliated graphite with a polyethylene resin from a circular die or T die to produce a medical film. Also good.

  Next, an example of how to use the medical film will be described. The medical film can be used for various medical uses, for example, for the production of a packaging bag for storing a medicine.

  The method for producing the packaging bag using the medical film is not particularly limited. For example, the medical film is cut into a flat rectangular shape, the medical film is folded in two, and then the four-side outer periphery of the medical film is used. A packaging bag can be manufactured by heat-sealing the part.

  The medical film contains exfoliated graphite, and the exfoliated graphite has conductivity, so the medical film has excellent antistatic properties, and can be stored and medicalized after the production of the medical film. During the processing of the medical film, foreign matter such as dust does not adhere to the surface of the medical film due to static electricity, and the medical film of the present invention can be suitably used for medical applications.

  And since exfoliated graphite contained in a medical film has excellent thermal conductivity, even when the medical films are heat-sealed as described above, the medical film The heat applied to the surface of the medical film is reliably transmitted to the inside of the medical film through the exfoliated graphite, so that the heat-sealed portion of the medical film including the inside of the medical film can be heated as a whole. . Therefore, the medical film can be heat-sealed without being heated to such a high temperature when the medical film is heat-sealed, and the manufacturing cost can be reduced and the manufacturing efficiency can be improved.

  In addition, when heat-sealing medical films, convex portions A2 due to exfoliated graphite are formed on each of the facing surfaces of the medical films, and voids are formed between the convex portions A2 and A2. The air existing between the opposing surfaces of the medical film A can be smoothly discharged to the outside through the gaps, and the medical films A and A can be firmly and reliably fused together. it can.

  Since the medical film of the present invention is characterized in that exfoliated graphite is contained in a polyethylene-based resin, it has excellent slipperiness, conductivity, and heat-fusibility, and various medical uses Can be easily processed.

  And the medical film of this invention has the outstanding transparency, and when it uses for the packaging bag etc. of a chemical | medical agent, the state of the chemical | medical agent accommodated in the inside can be visually recognized easily. Furthermore, since the medical film of the present invention only contains exfoliated graphite, which is a laminate of a plurality of graphene sheets, it causes alteration of drugs that come into contact with the medical film and adverse effects on the human body. There is no such thing.

It is the schematic cross section which showed the medical film of this invention. It is a typical perspective view for demonstrating the process of inserting an electrode in graphite. It is a typical perspective view which shows the state by which the electrode was inserted in graphite. It is a schematic diagram for demonstrating the process of performing an electrochemical process. It is the schematic diagram which showed the process of rolling the sheet | seat consisting of the graphite used as a raw material, and obtaining sheet-like graphite. It is the figure which showed the voltage application pattern at the time of applying a voltage to a graphite sheet by an electrochemical process.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

(Examples 1 to 5, Comparative Examples 1 and 2)
Graphite powder was preliminarily formed into a sheet to produce a preformed sheet. As shown in FIG. 5, this preformed sheet was fed between rolls 12 and 13 and rolled to prepare a low density graphite sheet having a density of 0.7 g / cm ³ and a thickness of 1 mm.

The graphite sheet having a density of 0.7 g / cm ³ obtained as described above was cut into a flat square shape having a side of 3 cm to obtain a graphite sheet as an electrode material. In this graphite sheet, as shown in FIG. 2, two slits were formed by cutting with a cutter knife such that the slit length was 1 cm and the width was 1 cm. The electrode 2 made of Pt shown in FIG. 2 was inserted into the graphite sheet on which the two slits were formed. The graphite sheet thus prepared was immersed in a 60 wt% nitric acid aqueous solution together with a reference electrode (cathode) made of Pt and a reference electrode made of Ag / AgCl as a working electrode (anode), and a DC voltage was applied. Electrochemical treatment was performed. In the electrochemical treatment, the voltage shown in FIG. 6 was applied for 2 hours. Thus, the graphite used as the working electrode for the anode was used as expanded graphite.

  The obtained expanded graphite was cut into a flat square shape having a side of 1 cm to produce a cut piece, and the cut piece was placed in a carbon crucible and subjected to electromagnetic induction heat treatment. As the induction heating apparatus, an apparatus commercially available from SK Medical Co., Ltd. under the trade name “MU1700D” was used, and the current was 10 A so that the maximum temperature reached 550 ° C. in an argon gas atmosphere. Exfoliated graphite was exfoliated by electromagnetic induction heating to obtain exfoliated graphite.

  The amount of linear low density polyethylene (trade name “MORETECH 0248Z” manufactured by Prime Polymer Co., Ltd.) in the amount shown in Table 1 and the exfoliated graphite were supplied to an extruder and melt-kneaded at 180 to 200 ° C. A cylindrical body is extruded from a circular die attached to the tip, compressed air is sent from the center of the cylindrical body to expand to a certain size, and cooling is performed by blowing 20 ° C. cooling air on the outer surface of the cylindrical body. Then, the medical film was manufactured by cut | disconnecting and developing a cylindrical body from a predetermined location.

  The both sides of the medical film obtained in Examples 1 to 5 are formed in a state in which convex portions having a substantially trapezoidal cross section due to the exfoliated graphite are scattered substantially uniformly, and are fine as a whole. Unevenness was formed. The medical film obtained in Comparative Example 2 had reduced transparency.

  The tensile strength and tensile elongation of the obtained medical film were measured in the following manner with respect to the extrusion direction (MD) and the direction (TD) perpendicular to the extrusion direction, and the results are shown in Table 1. Further, the friction coefficient (tan θ), surface roughness Ra, and transparency of the obtained medical film were measured in the following manner, and the results are shown in Table 1.

(Tensile strength)
The tensile strength of the obtained medical film was measured according to JIS K7127.

(Tensile elongation)
The tensile elongation of the obtained medical film was measured according to JIS K7127.

(Friction coefficient (tan θ))
The friction coefficient of the obtained medical film was measured according to JIS K7125: 1987.

(Surface roughness Ra)
The surface roughness Ra of the obtained medical film was measured according to JIS B0601.

(transparency)
The haze value of the obtained medical film was measured according to JIS K7136.

1a Slit 1 Sheet 2 Electrode
2a Insertion piece
2c Connecting part 6 Electrolyte solution 7 Counter electrode 8 Reference electrode
11 Pre-formed sheet
12 Roll A Medical film
A1 surface
A2 Convex G Graphene sheet

Claims (3)

A medical film characterized in that exfoliated graphite is contained in a polyethylene resin. A medical film characterized by containing exfoliated graphite in an amount of 0.005 to 2% by weight, and the remainder comprising a polyethylene resin. The medical film according to claim 1, wherein the polyethylene resin is a linear low-density polyethylene resin.

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