JP3006182B2 - Medical bag - Google Patents

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 storing blood, chemicals, etc., having excellent hygiene, flexibility, transparency and heat resistance. More specifically, the cross-linking rate is 20% or more in a laminate in which the inner and outer layers are made of low-density polyethylene and the intermediate layer is a copolymer of ethylene and 1-olefin having a density of 0.920 g / cm ³ or less. The present invention relates to a medical bag having excellent heat resistance.

[0002]

2. Description of the Related Art At present, a hard container made of glass, polyethylene, polypropylene or the like and a soft bag made of polyvinyl chloride containing a plasticizer are known as medical containers. However, in the former method, air must be introduced using a ventilation needle or an infusion set having a ventilation hole when the content liquid is dropped. In addition, contamination of the content liquid occurs. on the other hand,
The latter does not require the introduction of air, and has safety such as the bag itself being squeezed by the atmospheric pressure when the content liquid is dripped, and has convenient transportation. However, there are problems such as the toxicity of the plasticizer and residual monomers contained in polyvinyl chloride.

On the other hand, a medical bag using a polymer such as an ethylene-vinyl acetate copolymer or an elastomer for an intermediate layer has been proposed in view of flexibility, transparency, hygiene and the like (Japanese Patent Application Laid-Open No. Sho. 58-165866), however, these polymers used for the intermediate layer have poor heat resistance, so that there is a problem that a medical bag with poor appearance such as a wrinkled state of the bag during sterilization is obtained. In addition, those made of polyethylene have poor heat resistance, so the sterilization temperature cannot be raised and the processing time is prolonged, or the processing is performed in a highly clean atmosphere. Has been pointed out.

[0004]

In view of the above, the object of the present invention is to eliminate these drawbacks (problems), that is, not only good hygiene and flexibility, but also 125 ° C., 30 ° C.
An object of the present invention is to provide a polyethylene-based medical bag in which transparency is not lost even after high-temperature sterilization for a minute and wrinkles are not generated or deformed, and heat resistance is remarkably improved.

[0005]

According to the present invention, the above object is achieved by forming the inner and outer layers from low-density polyethylene and forming the intermediate layer from a copolymer of ethylene and 1-olefin having a density of 0.920 g / cm ³ or less. The problem can be solved by a medical bag characterized in that the cross-linking rate of the polymer laminate is 20% or more. Hereinafter, the present invention will be described specifically.

(A) Low-density polyethylene The low-density polyethylene constituting the inner layer and the outer layer of the present invention usually has a density of 0.930 g / cm ³ or less, has much better hygiene than polyvinyl chloride, and has good flexibility. sex,
It is transparent, but has a density of 0.920 due to sterilization temperature conditions.
g / cm ³ or more is preferred. The low-density polyethylene is a so-called high-pressure polyethylene having a main chain and a long-chain branch. Here, the long-chain branch has a length sufficiently comparable to the main chain, and means, for example, a branch having 15 or more carbon atoms.

(B) Copolymer of ethylene and 1-olefin Further, the copolymer of ethylene and 1-olefin (hereinafter referred to as “ethylene copolymer”) constituting the intermediate layer of the present invention is: Its density is 0.920 g / cm ³ or less,
It is preferably 0.915 g / cm ³ or less, particularly 0.9 g / cm ³ or less.
Those having 10 g / cm ³ or less are preferred. The 1-olefin used in the production of this ethylene-based copolymer is usually an α-olefin having at most 12 carbon atoms, and typical examples are propylene, butene-1, hexene-1, and 4-olefin.
Methylpentene-1 and octene-1 are mentioned.
In this copolymer, the density of the 1-olefin copolymerized as a comonomer decreases as the copolymerization ratio of the comonomer increases. That is, not only does the density decrease with the increase in the short-chain branching resulting from the 1-olefin, but also the flexibility and the excellent transparency are improved with the increase in the long-chain branching of the low-density polyethylene. However, the melting point of low-density polyethylene decreases as the density decreases, whereas the melting point of the copolymer of ethylene and 1-olefin is saturated at about 120 ° C. Deviates from the relationship between the density and the melting point. It has been found that by making use of this property, it is rich in flexibility and is applied not only to flexibility but also to heat resistance by being applied as a material for an intermediate layer having excellent transparency and heat resistance. The above “short-chain branching” is sufficiently short compared to the main chain and has 15 carbon atoms.
Branch less than. The density of the copolymer is 0.915 g /
Those having cm ³ or less (especially 0.910 g / cm ³ or less) not only have excellent transparency, but also have particularly high flexibility and good adhesion to the low-density polyethylene constituting the inner and outer layers. This is convenient.

[0008] The melt flow index of the above low density polyethylene and a copolymer of ethylene and 1-olefin (measured under condition 4 according to JIS K7210).
(Hereinafter referred to as “MFR”) is usually 0.1 to 20 g / 10 min from the viewpoint of moldability, strength and the like, and 0.1 to 15 g / 1.
A time of 0 minutes is desirable, and a time of 0.1 to 10 g / 10 minutes is particularly preferable.

(C) Production of laminate, production of medical bag In order to obtain the laminate of the present invention, a water-cooled or air-cooled coextrusion inflation method, a coextrusion T-die method, a dry lamination method, an extrusion lamination method, etc. Although a water-cooled coextrusion inflation method and a coextrusion T-die method are preferable from the viewpoint of economy, they can be employed. The laminate is usually in the form of a tube or a sheet. The medical bag of the present invention can be manufactured by manufacturing it into a predetermined shape and size by heat sealing, attaching an injection port, and cross-linking.

The thickness of the laminate is preferably from 0.15 to 0.5.
If it is 6 mm and less than 0.15 mm, the feeling of mass is impaired. On the other hand, if it exceeds 0.6 mm, the flexibility tends to be insufficient. The thickness ratio of each layer is not particularly limited, but in order to sufficiently impart flexibility to the laminate, the thickness of the intermediate layer is preferably 60% of the thickness of the laminate.
If it is less than 01 mm, the heat seal strength may be weak.

(D) Crosslinking of Laminate The method of crosslinking the laminate includes chemical crosslinking (for example, peroxide) and radiation crosslinking (for example, electron beam). The crosslinking ratio is preferably 20% or more in terms of gel fraction,
More preferably, it is 25% or more and 95% or less. Considering economics, it is recommended to be 30% or more and 90% or less. Here, the gel fraction represents the extraction residue obtained by extraction with boiling toluene in terms of weight percentage. It is generally known that cross-linking of polyethylene or the like by electron beam (EB) irradiation or the like improves heat resistance, particularly the shape retention at high temperatures. However, in general, in the case of thick film / sheets, the irradiation is performed from the surface layer, so that the surface layer portion is selectively cross-linked, and the inside of the film / sheet is hardly cross-linked. Distribution and the degree of cross-linking differs between the inside and the surface layer, so when the film / sheet is treated at high temperature for sterilization, wrinkles are generated due to internal strain, etc. I let it. In addition, if the irradiation time is increased to increase the degree of internal crosslinking, the surface layer is deteriorated, and there is a problem in terms of economic cost.

In order to solve these problems, the present inventors have continued intensive studies, and the degree of cross-linking by EB irradiation or the like, especially for ethylene and 1-olefin copolymer, is 1- It was found that those having a high degree of copolymerization with olefins, particularly having a high density dependency, and having a high degree of copolymerization with 1-olefins (low density) were very easily crosslinked. Therefore, paying attention to this feature, the film / sheet is formed as a laminate having a three-layer structure, and particularly the intermediate layer is a copolymer having a lower density than the surface layer, particularly a copolymer of ethylene and 1-olefin, and having a density of 0.920 ( g / cm ³ ) or less, and the ratio of this layer is remarkably increased, whereby the cross-linking of the intermediate layer portion becomes remarkably large under the same conditions, and the above-mentioned problem can be solved. Was.

[0013] If necessary, the medical bag thus obtained may be washed with distilled water, disinfecting water or the like at a predetermined temperature before filling with the contents liquid, and then filled with the contents liquid after drying. . Then, a sterilization treatment is performed. As a method using high-pressure steam, a sterilization condition is not particularly limited, but is usually 30 minutes at a temperature of 115 ° C. and 20 minutes at a temperature of 125 ° C. Minutes. After sterilization, the heat treatment at a temperature of 40 ° C. or more for about 10 minutes improves the transparency of the medical bag.

[0014]

The present invention will be described in more detail with reference to the following examples. In Examples and Comparative Examples, the density was 23 ° C. ± 0.1 according to the method D of JIS K7112.
Measured at a temperature of ° C. The cross-linking rate was calculated by putting a sample (3.5 × 3.5 cm: film) in a stainless steel mesh, heating and refluxing with boiling toluene for 2 hours to perform extraction, and extracting the residue after drying under reduced pressure by weight percentage. Further, the cross-linking is performed by EPS-750 manufactured by Nissin High Voltage Co., Ltd.
When a mold was used and the dose was 10 Mrad at an acceleration voltage of 750 kV, electron beam irradiation was performed at 9.30 mA, at a speed of 1.2 m / min., And in an irradiation atmosphere of air at room temperature. For the appearance inspection of the sample, after filling the bag with the content liquid (pure water),
Heat treatment was performed at 125 ° C. for 30 minutes to observe deformation and breakage of the entire bag (hereinafter referred to as “appearance I”), generation of wrinkles inside the bag, and reduction in transparency (hereinafter referred to as “appearance II”). This is shown in the following four ranks. ◎: very good 良好: good や: slightly poor ×: poor The resin is low density polyethylene with a density of 0.921 g /
cm ³ (hereinafter referred to as “LDI”), 0.929 g / cm
³ (hereinafter referred to as “LDII”) and a copolymer of ethylene and 1-olefin having a density of 0.910 g
/ Cm ³ of ethylene-butene 1 copolymer (hereinafter referred to as “co”). Table 1 shows the total thickness of each film and the type or composition of the resin used for each layer. Table 2
Shows the measurement results of the above Examples and Comparative Examples.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

The medical bag of the present invention has a stable appearance and quality even after sterilization at a high temperature of 125 ° C., and has greatly improved heat resistance as a polyethylene-based medical bag.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-191459 (JP, A) JP-A-62-44256 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 27/32 A61J 1/10 B65D 65/00-65/46

Claims (1)

(57) [Claims] An inner layer and an outer layer are made of low-density polyethylene, and an intermediate layer is made of ethylene having a density of 0.920 g / cm ³ or less.
A cross-linking ratio of 20 in a laminate comprising a copolymer with an olefin;
% Medical bag.