JPH04266759A - Medical bag - Google Patents

Abstract

PURPOSE:To obtain a polyethylene medical bag of three or more laminated film layers having high performance in transparency, flexibility, appearance and the like, even with an increase in heat resistance temperature up to 121 deg.C at a steam sterilizing process, and enabling a film therefor to be formed very stably for a long time. CONSTITUTION:A medical bag comprises a laminated film of three or more layers. Two or more types of special polyethylene such as LDPE and HDPE are blended according to a proper blending formula to control the outer, intermediate and inner layers of the film, thereby enabling the bag to resist a high temperature of 121 deg.C at a sterilizing process, and ensuring film forming stability. According to this construction, sterilizing temperature conventionally restricted for a polyethylene bag can be raised to 121 deg.C and the application field thereof can be expanded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical bag for filling blood, medical solutions, etc. with excellent hygiene, flexibility, transparency, and heat resistance. More specifically, it relates to a medical bag made from a sheet consisting of three or four or more layers, each layer made of polyethylene resin or a composition thereof, and which has excellent hygiene, flexibility, and transparency. The present invention provides medical bags that can be filled with blood, medical solutions, etc., and have excellent heat resistance.

0002

2. Description of the Related Art At present, as medical containers, hard containers made of glass, polyethylene, polypropylene, etc., and soft bags made of polyvinyl chloride containing a plasticizer are known. However, in the former case, air must be introduced using a ventilation needle or an infusion set with a ventilation hole when dropping the contents. Furthermore, contamination of the liquid content may occur. on the other hand,
The latter does not require the above-mentioned introduction of air, and the bag itself is squeezed by atmospheric pressure as the liquid contents drip, resulting in safety and convenience in transportation. However, there are problems such as the toxicity of the plasticizers and residual monomers contained in polyvinyl chloride.

[0003] In contrast, medical bags using polymers such as ethylene-vinyl acetate copolymers and elastomers as the intermediate layer have been proposed in terms of flexibility, transparency, hygiene, etc. 58-165866), but these polymers used for the intermediate layer have poor heat resistance, which causes wrinkles in the bag during sterilization, resulting in a medical bag with poor appearance. Based on these considerations, some of the inventors of the present invention have searched for various medical bags for filling blood, medical solutions, etc. that are excellent in hygiene, flexibility, transparency, and heat resistance, and have developed a bag consisting of three layers, each of which has excellent hygiene, flexibility, transparency, and heat resistance. It was discovered that a medical bag made of a sheet whose layer is made of polyethylene resin satisfies the above-mentioned characteristics, and previously proposed it (Japanese Patent Laid-Open No. 62-44
No. 256, No. 62-64363).

0004

[Problem to be solved by the invention] Said Japanese Unexamined Patent Publication No. 62-44
In the invention described in the specification of Japanese Patent No. 256, the outer and inner surface layers are composed of low density polyethylene resin produced using a radical catalyst (the intermediate layer is a linear low density polyethylene resin). For this reason, when the contents of the medical bag are treated with high-pressure steam at 120°C for the purpose of sterilizing the contents, the heat resistance is not always satisfactory because the outer surface layer is made of low-density polyethylene resin. Ta. For example, if the bag is treated with the above-mentioned high-pressure steam for 20 minutes, the sealing strength of the bag is insufficient and the drop strength is also unsatisfactory. Moreover, it is not sufficient in terms of flexibility and transparency, and there is some deformation.

[0005] Furthermore, in the invention described in JP-A-62-64363, all the layers are made of linear polyethylene resin. The linear polyethylene resin is produced using a so-called Ziegler catalyst. Therefore, there is a concern that trace amounts of titanium and aluminum present in the linear polyethylene resin constituting the inner surface layer may leak into the contents (medicinal solution, blood, etc.) filled in the medical bag. Moreover, calcium stearate, which is added to neutralize the halogen atoms (generally chlorine atoms) constituting the catalyst system, also causes the problem of an increase in the number of fine particles. Therefore, in order to almost completely remove the catalyst system remaining in the linear polyethylene resin, a catalyst system removal process is necessary, and even if the catalyst system is removed, the effect is still satisfactory. It's difficult to do.

In order to solve these problems, some of the inventors of the present invention proposed in Japanese Patent Application No. 2-149488 a method that can withstand high-pressure steam sterilization at 120°C by improving the composition of the inner and outer layers. I came. This method certainly yielded a medical bag that could sufficiently withstand high-pressure steam sterilization at 120°C for 20 minutes. However, it has been found that when long-term continuous operation is carried out commercially using this composition, there is a problem in the stability of film formation, that is, in the uniformity of quality, during the cooling stage of the melt bubble. That is, by using 50% or more of linear polyethylene resin in the outer surface layer, the melt elasticity of the molten film decreases, the crystallization rate increases, and uniform cooling becomes difficult. The characteristics affected the molten film, making stable molding difficult.

[0007] Based on the above, the present invention has an even higher temperature of 12
Even when sterilized with high-pressure steam at 1°C for 20 minutes, there is almost no deformation, the seal strength and drop strength are small, and flexibility and transparency are maintained, and as mentioned above, it is suitable for long-term continuous production. The purpose of the present invention is to provide a medical bag that can be stably molded even in a variety of conditions.

[0008]

[Means for Solving the Problems] According to the present invention, these problems are solved by a medical bag made from a laminated film, sheet or tube consisting of three or more layers,
The inner and outer layers are made of low-density polyethylene resin obtained by radical polymerization with a density of 0.930 g/cm3 or less, and a density of 0.945 g/cm3 or more and Mw/Mn of 4.
．． The intermediate layer is made of a composition containing 5 to 40% of high density polyethylene resin with a density of 0 or less, and the intermediate layer is a linear low density polyethylene copolymer having short chain branches with a density of 0.920 g/cm or less, and a density of 0.945 g/cm3 or less. cm3 or more and Mw/M
At most 1 high-density polyethylene resin with n of 4.0 or less
This solution can be achieved by a medical bag characterized in that it consists of a composition containing 5%.

The present invention will be specifically explained below. The low density polyethylene obtained by the radical polymerization method of 0.930 g/cm3 or less used in the present invention is generally produced by polymerizing ethylene under high pressure (usually 700 to 3000 kg/cm2), and is industrially It is manufactured as a high-pressure polyethylene resin. The MFR of the resin is 0.1 to 10 g/10 minutes, preferably 0.2 to 8.0 g/10 minutes, and particularly preferably 0.3 to 5.0 g/10 minutes. Also, the density is 0.910 to 0.930g/cm3, and 0.91
5 to 0.928 g/cm3 is preferred, especially 0.928 g/cm3.
918 to 0.927 g/cm3 is suitable. If the density is less than 0.910 g/cm3, the obtained medical bag will deform during high-pressure steam sterilization and wrinkles will occur, which is not preferable.

[0010] Also, high-density polyethylene with a density of 0.945 g/cm3 or more and Mw/Mn of 4.0 or less has a linear structure produced by homopolymerization of ethylene or copolymerization of ethylene and α-olefin. It is a polyethylene resin with The density of the resin is 0.945 to 0.970
g/cm3, and 0.950 to 0.965 g/cm
3 is preferred, especially 0.952 to 0.960 g/
cm3 is preferred. The MFR of the resin is 0.1 to 20
g/10 minutes, preferably 0.2 to 10 g/10 minutes, particularly preferably 0.3 to 5.0 g/10 minutes. In addition, a major feature of this resin is its molecular weight distribution, Mw/Mn
(Mw: Weight average molecular weight determined by GPC, Mn: GPC
It is necessary that the molecular weight distribution (number average molecular weight determined by ) is small, that is, the molecular weight distribution is narrow, and if Mw/Mn exceeds 4, the transparency of the film, sheet, etc. will deteriorate significantly. Mw/Mn is 4.0
-2.2, preferably 3.8-2.2, preferably 3.5-2
．． 2 is more preferred.

Furthermore, the density 0 used in the present invention
．． The polyethylene resin having a weight of 920 g/cm 3 or less has a number of branches of 20 to 70 per 1000 carbon atoms in the main chain, and a density of 0.890 to 0.920 g/cm 3 . Moreover, MFR is 0.1-10g/10min. Moreover, the melting point peak measured by DSC is 110-125℃
It appears in The number of short chain branches per 1000 carbon atoms in the main chain is 20 to 70, preferably 30 to 70, and particularly preferably 35 to 70. Polyethylene resins having less than 20 branches per 1000 carbon atoms in the main chain have poor flexibility when formed into a film or sheet, and are not preferred as the medical bag of the present invention. On the other hand, anything over 70 pieces is not currently commercially produced. Also, the density is 0.890 to 0.920
g/cm3, and 0.890 to 0.915 g/cm
3 is desirable, especially 0.890 to 0.91
0 g/cm3 is preferred. Density is 0.890g
/cm3 polyethylene resins are not currently produced commercially. On the other hand, if it exceeds 0.920 g/cm3, the flexibility will be poor when formed into a film or sheet, which is not preferable for the medical bag of the present invention. Further, the MFR is 0.1 to 10 g/10 min, preferably 0.2 to 10 g/10 min, and particularly 0.2 to 10 g/10 min.
3 to 5.0 g/10 minutes is suitable.

[Sheet and Method for Producing the Same] To produce the medical bag of the present invention, first a film or sheet consisting of the above-mentioned layers is produced. This film or sheet may be in the form of a tube. In the sheet of the present invention,
The polyethylene resin used to construct each layer should be of the composition described above for each layer. The density in these compositions is 0.945 g/cm3 or more and M
The proportion of high-density polyethylene resin having w/Mn of 4.0 or less is preferably 5 to 40% in the case of the inner and outer layers, and particularly preferably 10 to 37%. Further, in the case of an intermediate layer, it is desirable that the amount is at most 15%. In the case of the inner and outer layers, if the proportion of the above-mentioned high-density polyethylene is less than 5%, the heat resistance will be insufficient and the appearance after retorting at 121° C. for 30 minutes will be poor. On the other hand, if it exceeds 40%, molding stability during long-term continuous production will deteriorate. In the case of the intermediate layer, if it exceeds 15%, heat resistance will improve, but transparency and flexibility will decrease, and molding stability will also deteriorate, which is not preferable.

[0013] The overall thickness of the film or sheet of the present invention is usually 0.10 mm to 0.80 mm;
0.15 to 0.70 mm is desirable, especially 0.15
~0.50 mm is suitable. If the total thickness of the film or sheet is less than 0.10 mm, the impact strength will be low and there will be a practical problem. On the other hand, if it exceeds 0.80 mm, the flexibility will be significantly reduced and the practicality as a medical bag will be poor.

[0014] Furthermore, when comparing the thickness ratio of each layer of the film sheet: outer surface layer/intermediate layer (including multilayers)/inner surface layer, it is generally 5:90:5 to 30:40:30. , 5:90:5 to 25:50:25, and particularly preferably 5:90:5 to 20:60:20. If the outer surface layer and inner surface layer are below the lower limit, the resulting medical bag will not have good heat resistance (it may become deformed if sterilized with high pressure steam at 121° C. for 20 minutes). On the other hand, if the upper limit is exceeded, the resulting medical bag will be less flexible;
There are practical problems.

[0015] To produce the film or sheet of the present invention, water-cooled or air-cooled coextrusion inflation method;
Examples include a coextrusion T-die method, a dry lamination method, an extrusion lamination method, and the coextrusion inflation method and coextrusion T-die method are preferred from the viewpoint of economy and hygiene of medical bags.

[Medical bag and its production] The film or sheet obtained as described above or its tube-like product is given a predetermined shape and shape as appropriate by applying the method used in producing general bags. The medical bag of the present invention can be manufactured by making the bag according to the dimensions and attaching an outlet (spout).

[0017]

[Examples] The present invention will be explained in more detail below with reference to Examples and Comparative Examples. In addition, in the examples and comparative examples,
Density is determined at 23℃ according to D method of JIS K7112.
Measurements were made at a temperature of ±0.1°C. Also, flexibility is A
Young's modulus was measured according to STM D-882. Transparency was evaluated by high-pressure steam sterilization at a temperature of 121°C for 30 minutes after filling with the content liquid, and by measuring haze in accordance with ASTM D-1003 method. Furthermore, the evaluation based on appearance was shown in the following three ranks. ○: Good. △: Wrinkles and shrinkage have occurred. ×: Shrinkage occurs and the shape is deformed. Next, the moldability was evaluated by water-cooled three-type three-layer coextrusion inflation molding, and the results were given in the following three ranks. ○: Bubble is stable and stable molding is easy. △: Bubble is unstable and shear is likely to occur. ×: Bubble is extremely unstable and continuous molding is difficult.

Examples 1 to 6, Comparative Examples 1 to 8 Low density polyethylene (abbreviated as LDPE), high density polyethylene (abbreviated as HDPE) and linear low density polyethylene (abbreviated as L-LDPE) with the densities shown in Table 1. ), two types of combinations with different ratios of each composition are prepared in advance.
Each of the obtained mixtures was kneaded using a single screw extruder (screw diameter: 65 mm) at a resin temperature of 180° C. to produce a pellet-like composition. Next, laminates were produced from these compositions using a water-cooled three-type three-layer coextrusion inflation molding machine so as to form an outer layer, an intermediate layer, and an inner layer having the respective thicknesses shown in Table 1. A medical bag with an internal volume of 500 ml was manufactured from the laminate thus obtained and evaluated as described above. The results obtained are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[0021] As is clear from these Examples and Comparative Examples, only medical bags manufactured using a laminate composed of a composition in a specific composition range have good transparency, flexibility,
It had an excellent appearance after retorting at 121°C and showed good results in continuous moldability.

[0022]

Effect of the invention: The medical bag of the present invention not only has excellent transparency and flexibility, but also can be continuously molded at 121°C.
Since it shows sufficient heat resistance even after 0 minutes of retort treatment, it is useful as a medical bag for high temperature sterilization.

Claims (1)

[Claims] Claim 1: A medical bag made from a laminated film, sheet, or tube consisting of three or more layers, the inner and outer layers being made of low-density polyethylene resin obtained by radical polymerization with a density of 0.930 g/cm3 or less. The density is 0.945 g/cm3 or more and the Mw/Mn is 4.
The intermediate layer consists of a composition containing 5 to 40% of high density polyethylene resin with a density of 0.920 g/cm or less and a linear low density polyethylene copolymer having short chain branches with a density of 0.945 g/cm3 or less. At most 15% of high-density polyethylene resin with Mw/Mn of 4.0 or less
A medical bag comprising a composition comprising: