JPH0440956A - Bag for medical treatment - Google Patents

Abstract

PURPOSE:To obtain the bag for medical treatments having an excellent hygienic property, softness, transparency, and heat resistance by forming the bag of a sheet consisting of three or four layers and constituting the respective layers of specific polyethylene (PE) resins or the compsns. thereof. CONSTITUTION:The bag for medical treatments is formed of the sheet consisting of the three or four layers. The outside surface layer thereof is constituted of the compsn. contg. the PE resin I or <=50 wt.% PE resin I and PE resin II. The inside surface layer is constituted of the compsn. contg. the PE resin II or the PE resin II and <=50 wt.% PE resin I. The intermediate layer is constituted of the compsn. contg. the PE resin III or the PE resin III and <=50 wt.% PE resin II. The number of the branches of the short chains of the PE resin I is 1 to 30 pieces per 1000 C pieces of the main chain and the density thereof is 0.920 to 0.970 g/cm<3>. The PE resin II is produced by using a radical catalyst and has the branches of the long chain. The number of the branches of the short chains of the PE resin III is 1 to 70 pieces per 1000 C pieces of the main chain and the density thereof is 0.800 to 0.930 g/cm<3>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 of a sheet consisting of three or four or more layers, each layer made of polyethylene resin or a composition thereof,
Blood with excellent hygiene, flexibility, transparency, and heat resistance,
The company provides medical bags that can be filled with medical solutions and the like.

[Conventional technology]

Currently, as medical containers, hard containers made of glass, polyethylene, polypropylene, etc., and soft bags made of polyvinyl chloride containing a plasticizer are known. but,
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, it causes staining of the liquid content. 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 with the plasticizers contained in polyvinyl chloride and the toxicity of residual monomers.

In response, a medical bag using a polymer such as ethylene-vinyl acetate copolymer or elastomer as an intermediate layer has been proposed in terms of flexibility, transparency, hygiene, etc. (Japanese Patent Laid-Open No. 58-165866 However, because these polymers used for the intermediate layer have poor heat resistance, there are problems such as wrinkles appearing on the bag during sterilization, resulting in medical bags with poor appearance.

For these reasons, some of the inventors of the present invention have searched for various medical bags for filling blood, medical fluids, etc. that are excellent in hygiene, flexibility, transparency, heat resistance, etc., and have developed a three-layer medical bag, which has three layers. We have previously proposed that a medical bag made from a sheet made of polyethylene resin in each layer satisfies the above characteristics (Japanese Patent Laid-open No. 44256/1983, No. 62 -64363).

[Invention or problem to be solved]

In the invention described in the specification of JP-A No. 62-44256, the outer and inner surface layers are made of low density polyethylene resin produced using a radical catalyst (the intermediate layer is made of 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, with the high pressure steam mentioned above,
When treated for 0 minutes, the sealing strength of the bag was insufficient (and the drop strength was also unsatisfactory).Furthermore, the flexibility and transparency were insufficient, and there was some deformation.

Furthermore, in the invention described in Japanese Patent Application Laid-Open No. 62-64363, all 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, there is another problem in that the amount of fine particles increases due to carunium stearate, which is added to neutralize the halogen atoms (generally chlorine atoms) constituting the catalyst system. 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.

From the above, even if the present invention is sterilized with high-pressure steam at 120°C for 20 minutes, there is almost no deformation, the seal strength and drop strength are reduced to a small extent, and flexibility and transparency are maintained. The purpose of the present invention is to provide a medical bag that does not use linear polyethylene resin for the inner surface layer, which has problems such as oozing out (even if it is used, the result is only ff1).

[Means and effects for solving the problems] According to the present invention, these problems are a medical bag made of a film or sheet having three or more layers, and (A) an outer surface. The layer has 1 to 30 short chain branches of ~10 carbons per 1000 carbons of the main chain.
and has a density of 0.920 to 0.970g/
cI? and the melt flow rate [JISK7210
Measured under condition 4, hereinafter referred to as rMFRJ]
is 0.1 to 10 g/10 min, and a differential scanning calorimeter [Differential Scanning Calorimeter]
10rimeter, hereinafter referred to as rDscJ] whose melting point peak is 118 to 135°C [hereinafter referred to as "polyethylene resin (I)"], or manufactured using the polyethylene resin (1) and a radical catalyst. and the density with long chain branches is 0.915 to 0.
930g/c? From a composition containing at most 50 weight Ob of a low-density polyethylene resin [hereinafter referred to as "polyethylene resin (■)"] having an MFR (melt flow rate) of 0.1 to 10 g/10 minutes. (B) the inner surface layer is comprised of a composition containing the polyethylene resin (n) or polyethylene resin (II) and at most 50% by weight of the polyethylene resin (1); and (C) the intermediate layer comprises: , the number of short chain branches is 10 to 70, and the number of carbon atoms is 1 to 10 per 1000 carbon atoms in the main chain.
and has a density of 0.890 to 0.930g/
cIl? The MFR is 0.1~lOg/10 minutes, and the melting point peak measured by DSC is 110.
Linear low density polyethylene resin shown at ~128℃ [hereinafter “
or a composition containing at most 50% by weight of the polyethylene resin (m) and the polyethylene resin (II) constituting the inner surface layer; Between the intermediate layer and the outer surface layer, there is a polyethylene resin (n) or polyethylene resin (II) constituting the inner surface layer and at most 50 times ML 90.
Between the layer and/or intermediate layer of the composition containing the polyethylene resin (1) and the inner surface layer, there is a layer of at most 50 double layers with the polyethylene resin (I) or the polyethylene resin constituting the outer surface layer. % of polyethylene resin (I
A medical bag provided with a layer of a composition containing I). The present invention will be specifically explained below.

(A) Polyethylene resin (I) The polyethylene resin (1) used in the present invention has 1 to 30 short chain branches per 1000 carbon atoms in the main chain.
and the density is 0.920 to 0.970 g/CI
? It is. Further, the MFR is 0.1 to 10g/10 min. Moreover, the melting point peak determined by DSC (differential scanning calorimeter) is 118 to 135°C.

The number of short chain branches per 1000 carbon atoms in the main chain is 1 to 3.
The number is 0, preferably 1 to 25, and particularly preferably 4 to 20. A polyethylene resin having less than 1 branch per 1000 carbon atoms in the main chain has poor transparency and lacks flexibility. On the other hand, if the number exceeds 30, 1
During high temperature steam sterilization at 20°C, the surface force is deformed and the transparency is significantly inferior.

Here, the short chain has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms.

Also, the density is preferably 0.920-0.970g/cj tar'), 0.925-0.970g/c♂, especially 0.930-0.970g/c♂. %5g/c? Preferably. If a polyethylene resin with a density of less than 0.920 g/(J is used, the surface force will be deformed during high-pressure steam sterilization at 120°C, resulting in poor transparency. -X, 0.970 g/cI
If r is used too easily, it will be less flexible.

Further, MFR is 0.1 to 10 g/10 minutes, preferably 02 to 10 g/10 minutes, and particularly 0.1 to 10 g/10 minutes.
2 to 8.0 g/10 minutes is suitable. MFR is 0
．． If less than 1 g/10 min of polyethylene resin is used, the processability will be poor and the surface will be rough, making it impossible to form a smooth film or sheet. On the other hand, if it exceeds 10 g/10 minutes, the impact strength will be significantly weakened and there will be a problem in terms of practicality as a bag.

In addition, the melting point peak determined by DSC (Differential Scanning Calorimeter) at 711 is 118-135°C, and 120-135°C.
135°C is preferable, especially 122-13
2°C is suitable. If the peak is below 118°C, the surface will be deformed during high-pressure steam sterilization at 120°C, causing problems in terms of transparency. On the other hand, those exhibiting a temperature higher than 135°C have poor flexibility and transparency.

(B) Polyethylene resin (II) Also, polyethylene resin (n
) is produced using a radical catalyst.

This polyethylene resin is generally produced by polymerizing ethylene under high pressure (usually 700 to 3000 kg/an) using the above-mentioned catalyst.
It is manufactured industrially as a high-pressure polyethylene resin and is used in a wide variety of fields. This polyethylene resin (II) has long chain branches.

Here, a long chain branch has a length sufficiently comparable to that of the main chain, for example, a branch with a carbon number of 15
It means more than 30 (generally 30 or more) branches.

The MFR of the polyethylene resin (n) is 0.1 to 10 g for the same reason as the polyethylene resin (1) above.
/10 minutes, preferably 0.2 to 10 g/10 minutes,
Particularly suitable is 0.2 to B, D glJD.

Further, the density of the polyethylene resin (II) is 0.91
5 to 0.930 g/cm3, and 0.915 to 0.9
28g/c7 is preferred, especially 0.915-0.927
g/cI' is preferred. Density is 0.91.5g/cI
? If the polyethylene resin (II) is less than 100%, the obtained medical bag will have poor heat resistance and deformation or blocking will occur when the resulting medical bag is sterilized using high-pressure steam. On the other hand, 0.930g
If it exceeds /c7, the flexibility of the film decreases and the bag drop strength decreases, which is not preferable.

(C) Polyethylene resin (m) Furthermore, the polyethylene resin used in the present invention (
m) has 10 to 10 branches per 1000 carbon atoms in the main chain.
70 pieces, and the density is 0.890 to 0.930 g/
It is c7. Further, the MFR is 0.1-10 g/10 minutes. Moreover, the melting point peak measured by DSC is 11
0 to 125°C.

The number of short chain branches per 1000 carbon atoms in the main chain is 10 to 7.
0, preferably 20 to 70, particularly 25 to 70
Preferably. Polyethylene resins having less than 10 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.

In addition, the density is 0.890 to 0.930 g/c-,
0.890-0.920g/c? It is desirable that
Particularly suitable is one having a content of 0.890 to 0.915 g/c7. Density or 0. Polyethylene resins below g9Dg/ca are not currently produced commercially. On the other hand, 0.93
If it exceeds 0 g/cj, the flexibility will be poor when formed into a film or sheet, which is not preferable for the medical bag of the present invention.

Furthermore, MFR is 0.1 to 10 g/10 minutes for the same reason as the polyethylene resin (1) above, and 0
．． 2 to 10 g/10 min is preferable, especially 0.2 to 10 g/10 min.
8.0 g/10 minutes is suitable.

In addition, the melting point peak measured by DSC is 110 to 125.
℃, preferably IH to 124°C, and particularly preferably 115 to 122°C. Those exhibiting a peak below 110° C. are not currently produced commercially.

On the other hand, if the temperature is higher than 125°C, the flexibility will be poor when formed into a film or sheet, and this is not preferred as the medical bag of the present invention.

For both the polyethylene resin (1) and the polyethylene resin (II), ethylene and an α-olefin having 3 to 12 carbon atoms (preferably 3 to 8 carbon atoms) are combined using a so-called Phillips catalyst or a Ziegler catalyst. It is widely produced industrially by copolymerizing in the presence of polyethylene resin (1).
It is also produced by homopolymerizing ethylene alone using the above catalyst system. In any case, preferred α-olefins which are polymerized by a solution method, a gas phase method, etc. under normal pressure to about 100 kg/c7 pressure are propylene, butene-1, hexene-1, and hexene-1. ，
Examples include 4-methylpentene-1 and octene-1.

In both polyethylene resin (I) and polyethylene resin (m), "short chain branching" means
The branch is extremely short compared to the main chain, and usually has 15 or less carbon atoms (preferably 10 or less).

(D) Each layer In the medical bag of the present invention, the outer surface layer may be composed of the polyethylene resin (1) alone, or the polyethylene resin (1) and at most 50% by weight of the polyethylene resin (n). It may be composed of a composition containing. If the content of the polyethylene resin (If) in the composition exceeds 50% by weight, the surface will be molded during high-pressure steam sterilization at 120°C, resulting in poor transparency. For these reasons,
The content of polyethylene resin (II) in the composition is preferably 40% by weight or less, particularly preferably 35% by weight or less.

Further, the inner surface layer may be composed only of polyethylene resin (n), or may be composed of a composition containing polyethylene resin (II) and at most 50% by weight of polyethylene resin (1). good. If the content of the polyethylene resin (1) in the composition exceeds 50% by weight, it will come into direct contact with trace amounts of metal catalyst residues used during polymerization, additives used for neutralization, or the content liquid. Undesirable. For these reasons, the content of the polyethylene resin (1) in the composition is desirably 30% by weight or less, particularly preferably 20% by weight or less.

Furthermore, the intermediate layer may be composed of polyethylene resin (m) alone or of polyethylene resin (III) and a composition containing at most 50% by weight of polyethylene resin (II). If the content of the polyethylene resin in the composition exceeds 50% by weight, it is not preferable because the flexibility and transparency will be poor. For these reasons, the content of the polyethylene resin (n) in the composition is preferably 40% by weight or less, particularly preferably 35% by weight or less.

The medical bag of the present invention may be a three-layered bag comprising an outer surface layer and an inner surface layer on both surfaces, with the above-mentioned intermediate layer interposed therebetween.

Further, polyethylene resin (II) or polyethylene resin (
n) and at most 50% by weight of a polyethylene resin (1), said polyethylene resin (I) constituting said outer surface layer between the intermediate layer and the inner surface layer. Alternatively, a layer of a composition containing polyethylene resin (I) and at most 50% by weight of polyethylene resin (II) may be provided.

(E) Sheet and method for manufacturing the same To manufacture the medical bag of the present invention, first, a film or sheet consisting of the above-mentioned layers is manufactured.

This film or sheet may be in the form of a tube.

In the sheet of the present invention, polyethylene resin (1) to polyethylene resin C used to constitute each layer
I[I) may be the same or different. Further, in the case of each layer or composition, the composition ratio may be the same or different.

The overall thickness of the film or sheet of the present invention is usually 0.1 On+m to 0.80 m+m, and 0.15 On+m to 0.80 m+m.
~0.70++++s is preferred, especially 0.15-
0.50 mm is suitable. If the thickness of the film or sheet as a whole is less than 0.10 ohm, the impact strength will be low and there will be a practical problem. On the other hand, if it exceeds 0.80 m+m, the flexibility will be significantly reduced and the practicality as a medical bag will be poor.

In addition, the thickness ratio of each layer of the film sheet is the outer surface layer/
Comparison of intermediate layer (including multilayer)/inner surface layer: 90:5~ru,
Moan nine, good fortune, care suitable, ah. Outside. 7 and the inner surface layer is less than the lower limit, the heat resistance of the resulting medical bag is poor (
(It may become deformed if sterilized with high-pressure steam at 120°C for 20 minutes.) On the other hand, if the upper limit is exceeded, the flexibility of the resulting medical bag will be poor, which may pose a practical problem.

The film or sheet of the present invention can be produced by a water-cooled or air-cooled coextrusion inflation method, a coextrusion T-die method, a dry lamination method, an extrusion lamination method, etc., which are economical and hygienic for medical bags. From these points, the coextrusion inflation method and the coextrusion T-die method are preferred.

Even in the case of the above coextrusion inflation method, coextrusion T
Even in the case of the die method, and even when melt-kneading is performed when producing a composition in which each layer is a composition, polyethylene resin (1) or polyethylene resin (I) is used.
II) must be carried out at a temperature at which it melts. but,
If the temperature is too high, it must be carried out at a temperature that does not cause thermal decomposition of these polyethylene resins. For these reasons, the temperature range when carrying out the above is usually 150 to 210°C (preferably 160 to 200°C).
℃).

(P) Medical bags and their manufacture The film or sheet obtained as described above or its tube-like material is shaped into the desired shape and dimensions by applying the method used to manufacture general bags. The medical bag of the present invention can be manufactured by making a bag and attaching an outlet (spout).

FIG. 1 is a front view of a typical medical bag according to the present invention. In FIG. 1, 1 is a bag portion, 2 is an upper fused portion, and 3 is a lower fused portion. Also, 4 is the pouring inlet (spout)
It is. Furthermore, 5 is a boundary line, 5a is an edge,
5b is the terminal part.

6 is a hanging hole, and 7 is a transparent fused portion. In the medical bag shown in the front view or in FIG. 1, the upper fused portion 2 and the lower fused portion 3 may be transparent.

However, it may be knurled to make the fusion more reliable.

In order to manufacture the medical bag of the present invention, the upper fused part 2 and the lower fused part 3 of the medical bag shown in FIG.
The seal is heat sealed as is commonly practiced. Heat sealing is the temperature at which the low density polyethylene resin or its composition constituting the inner surface layer melts.

However, when heat sealing is performed at high temperatures, the outer surface layer, intermediate layer, and other films easily melt and become fluid, resulting in the thickness of the film at the sealed portion becoming extremely thin and its strength decreasing. From these facts, it is found that the melting point of the inner surface layer is 1
It is desirable to carry out the process at an elevated temperature of 0 to 30°C (preferably 10 to 25°C). Further, the spout port 4 is preferably made of the same type of low density polyethylene resin or its composition that constitutes the inner surface layer.

The important point of the medical bag obtained as described above is that the outer surface layer and the inner surface layer are provided with a composition mainly composed of the polyethylene resin (T) or its IUW within the above thickness range. As a result, it has excellent heat resistance, and by providing the intermediate layer with polyethylene resin (It) or a composition containing the resin as a main component, it has good flexibility.
In addition, by providing the polyethylene resin (II) or a composition containing the resin as a component on the inner surface layer, it is improved in terms of safety. We were able to obtain a good medical bag.

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, in the examples and comparative examples, the density is JIS K
7112, and measured at a temperature of 23°C±0.1°C. Furthermore, the melting point was determined according to the DSC method by increasing the temperature at a rate of 10° C. per minute and determining the peak temperature. Further, the flexibility was determined based on ASTM D-882, and the tensile modulus was determined as nj.

Furthermore, transparency is determined by high-pressure steam sterilization at 120°C for 20 minutes after filling with the contents, and 40 minutes at 40°C.
After heat treatment for 0 minutes, observation was made with the naked eye. Further, the transparency was evaluated by filling the container with physiological saline and observing the transparency after sterilization with the naked eye, and by measuring the haze (Ilaze) according to ASTM D-1003 method. Furthermore, the heat shrinkage rate is 1 t in the longitudinal direction at a temperature of 140°C according to JIS Z17 [19].
It was determined to be F1. In addition, hygiene was evaluated based on the results of a test based on the Japanese Pharmacopoeia Test Method for Plastic Containers for Infusions. Each bag was observed for wrinkles, deformation, and torn bags. Hygiene, drop strength, and appearance were ranked using the following four ranks.

◎: Very good 〇2 good Good △: Slightly poor ×: Poor In the examples and comparative examples, polyethylene resin (I) and polyethylene resin constituting the outer surface layer, intermediate layer, and inner surface layer of the medical bag The physical properties of (n) and polyethylene resin (III) are shown below.

[(A) Polyethylene resin (I)]

As polyethylene resin (I), the number of carbon atoms in the main chain is 1000
The number of ethyl groups per unit is 5, and the melting point peak is 1
The temperature is 28°C, and the MFR is 1.0 g 710 minutes,
Copolymer of ethylene and butene-1 in which the copolymerization ratio of butene-1 is 1 mol% [density 0.95] g/ca
s hereinafter referred to as "PE(a)J" and the number of carbon atoms in the main chain is 10
Ethylene having 12 butyl groups per 00, a peak melting point of 123°C, a VFR of 4.0 g/IQ min, and a hexene-1 copolymerization ratio of about 2.5 mol%. and hexene-1 copolymer [density 0.932
g/c? , hereinafter referred to as "rPE(b)"] was used. For comparison, the number of ethyl groups per 1000 carbon atoms in the main chain was 5, the MFR was 12 g/10 minutes, the melting point peak was 129°C, and the copolymerization ratio of butene-1 was A copolymer of ethylene and butene ~1 with a density of about 1 mol% [density 0.950 g/cs? , hereinafter referred to as “PF (
c) J] was used.

[(B) Polyethylene resin (■)]

In addition, polyethylene resin (If) is manufactured using a so-called high pressure method using a free radical catalyst. A missed MFR is 1.0g710 minutes and density is 0.9
281; /cI? polyethylene resin [hereinafter referred to as r
LDPE (named J) and VFR 3.0g
710 minutes and a density of 0.917 g/10 minutes (hereinafter referred to as rLDPE (2) J), an MFR of 0.5 g/10 minutes, and a density of 0.928 g/c♂. A certain polyethylene resin [hereinafter referred to as r
LDPE (3)J] and MFR is 5.0g
710 minutes and a density of 0.920 g/c7 [hereinafter referred to as rLDPE (4) J]
was used.

[(C) Polyethylene resin (■)]

Furthermore, the polyethylene resin (m) has 48 ethyl groups per 1000 carbon atoms in the main chain, has a melting point peak of 117°C, and has an MFR of 2.0 g/1.
0 minutes, and the copolymerization ratio of butene-1 is approximately 9.5 mol%.
A copolymer of ethylene and butene-1 [density 0.
895 g/cJ, hereinafter referred to as r P E (A) J] and the number of butyl groups per 1000 carbon atoms in the main chain is 37
, the peak melting point is 119°C, and the MFR
copolymer of ethylene and hexene-1 [density 0.905 g/ci, hereinafter referred to as rP
E (B)J] was used.

For comparison, the number of ethyl groups per 1000 carbon atoms in the main chain is 8, the peak melting point is 125°C, and the MFR is 0g710min, and the copolymerization rate of butene-1 is A copolymer of ethylene and butene-1 with a concentration of 1.6 mol% [density [1,925 g/c7, hereinafter referred to as rPE (
C) J] and the number of butyl groups per 1000 carbon atoms in the main chain is 20, the melting point is 120°C, the MFR is 15 g/10 min, and hexene A copolymer of ethylene and hexene-1 in which the copolymerization ratio of -1 is 4 mol% [hereinafter referred to as rPE (D)J]
It was used.

[(D) Composition]

In addition, as for the composition, each composition component was mixed in advance for 5 minutes using a Henschel mixer, and the resulting mixture was kneaded using a single screw extruder (screw diameter 65 mm) at a resin temperature of 180'C. A pelletized composition was produced. Table 1 shows the composition ratio and type of each composition component and the abbreviation of each composition obtained.

Table 1 1] Heavy % Examples 1 to 7, Comparative Examples 1 to 9 Intermediate layers with polyethylene resins or compositions whose types are shown in Table 2 as intermediate layers whose thicknesses are shown in Table 2. , laminated elongated products were produced by a water-cooled coextrusion method using polyethylene resins or compositions whose types are shown in Table 2 as inner and outer surface layers (Examples 1 to 5, Comparative Examples 1 to 6) .

Further, laminated elongated products were manufactured by the T-die method (Examples 6 and 7, Comparative Examples 7 to 9).

Examples 8 to 14 As intermediate layer (1) and intermediate layer (II) or intermediate layer (I), intermediate layer (II) and intermediate layer (III) whose respective thicknesses are shown in Table 3 or Table 4 The polyethylene resin or composition shown in Table 3 or Table 4 is interposed as the inner surface layer and the outer surface layer.
Laminated elongated products were manufactured using the polyethylene resins shown in Table 4 or Table 4 by a water-cooled coextrusion method.

A medical bag (inner volume: 500 m1), whose front view is shown in FIG. 1, was manufactured from each of the laminated elongated products obtained as described above. The tensile modulus (flexibility), thermal shrinkage rate, and haze (transparency) of the medical bag thus obtained were measured. The results are shown in Table 5.

From the results of the above Examples and Comparative Examples, the medical bag of the present invention not only has good flexibility (but also has low transparency, good hygiene, and especially heat resistance). It is clear that it is faint.

〔Effect of the invention〕

The medical bag of the present invention exhibits the following effects (features).

(1) Excellent heat resistance
Even after being sterilized for several minutes, the bag has almost no wrinkles or deformation, and has a good appearance.

(2) Due to its excellent flexibility, uneven discharge of the liquid content does not occur.

(3) Good transparency makes it easy to judge the state of the liquid content.

(4) Appearance (no wrinkles, deformation, etc.) is good, with almost no broken bags.

[Brief explanation of drawings]

FIG. 1 is a front view of a typical medical bag of the present invention. ]...Bag part 3...Lower fusion part 5... Boundary line 5b...terminal part 7...Fusion part

Claims (1)

[Scope of Claims] A medical bag made of a film or sheet consisting of three or four or more layers, wherein (A) the outer surface layer has 1 carbon per 1000 carbons in the main chain; The number of short chain branches is 1 to 30, and the density is 0.920 to 0.970 g/cm^3
A linear polyethylene resin having a melt flow rate of 0.1 to 10 g/10 minutes and a melting point peak of 118 to 135°C measured by a differential scanning calorimeter, or a linear polyethylene resin and a radical catalyst. The density of long chain branching is 0.915 to 0.930.
g/cm^3 and melt flow rate is 0.1
(B) an inner surface layer comprising at most 50% by weight of a low-density polyethylene resin or a low-density polyethylene resin and at most 50% by weight of the low-density polyethylene resin; The intermediate layer (C) is composed of a composition containing a linear polyethylene resin, and the number of short chain branches of 1 to 10 carbon atoms per 1000 carbon atoms in the main chain is 10 to 70. and the density is 0.890 to 0.930g/cm^3
A linear low-density polyethylene resin or a linear low-density polyethylene resin that has a melt flow rate of 0.1 to 10 g/10 minutes and a peak melting point of 110 to 128°C as measured by a differential scanning calorimeter. and a composition containing at most 50% by weight of the low-density polyethylene resin used in forming the inner surface layer, and between these three layers or the intermediate layer and the outer surface layer, the inner surface layer is Between the inner surface layer and the layer and/or intermediate layer of a low-density polyethylene resin or a composition containing the low-density polyethylene resin and at most 50% by weight of the linear polyethylene resin, the outer surface layer is provided. A medical bag comprising a layer of a composition containing at most 50% by weight of a linear polyethylene resin or a linear low-density polyethylene resin and a low-density polyethylene resin of at most 50% by weight.