JPH0244549B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a medical soft resin composition and a medical device. Specifically, the present invention relates to medical soft resin compositions and medical devices that have extremely high safety and do not cause hemolysis when they come into contact with blood. (Prior Art) Currently, blood storage containers and other medical devices made of soft vinyl chloride resin are widely used. By the way, soft vinyl chloride resins used for medical purposes as described above usually use di-2-ethylhexyl phthalate (DOP) as a plasticizer. However, since phthalate ester plasticizers generally have a high migration property, it is known that, for example, when a soft vinyl chloride resin such as the one mentioned above comes into contact with blood, di-2-ethylhexyl phthalate will be eluted into the blood. (Medical Science 54 221
(1984)). This di-2-ethylhexyl phthalate has been reported to suppress the aggregation ability of platelets (Journal of the Japanese Society of Blood Transfusion, 28(3)282 (1981)), and for example, storage containers made of soft vinyl chloride resin such as this When blood is stored using a blood transfusion method, di-2-ethylhexyl phthalate may enter the body along with the stored blood during blood transfusion, which is a problem from the perspective of affecting platelet function. In order to solve this problem, the use of materials that do not contain di-2-ethylhexyl phthalate has been considered, but storage containers constructed using materials that do not contain di-2-ethylhexyl phthalate It has become clear that when blood is stored, red blood cells become hemolyzed during storage. When the cause of this was investigated, it was found that di-2-ethylhexyl phthalate has a hemolysis suppressing effect (Blood 64 6 1270~ (1984) [Blood 64 6
1270−(1984)]). In other words,
When blood is stored in a conventional blood storage container made of soft vinyl chloride resin containing di-2-ethylhexyl phthalate as a plasticizer, di-2-ethylhexyl phthalate eluted into the blood can cause hemolysis of red blood cells. It was suppressed. For these reasons, although there are concerns about the effects of di-2-ethylhexyl phthalate on living organisms, soft vinyl chloride resin containing di-2-ethylhexyl phthalate is used as a medical soft resin composition constituting medical containers. The current situation is that (Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a novel medical soft resin composition and a medical device.
Another object of the present invention is to provide a medical soft resin composition and a medical device that have excellent preservability for red blood cells. A further object of the present invention is to provide a medical soft resin composition and a medical device with high physiological safety. A further object of the present invention is to provide a medical resin composition and a medical device that are autoclave sterilizable and have heat resistance, high transparency, flexibility, and processability. (Means for Solving the Problems) The above objects are achieved by applying the general formula () RCOOR' () (where R and R' each have 3 or more carbon atoms) into a soft resin composition that does not contain a plasticizer. A medical soft resin composition characterized in that it contains a monocarboxylic acid ester which is a chain hydrocarbon group and the sum of the carbon numbers of R and R' is 11 to 30. achieved. The present invention also provides a medical soft resin composition containing 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula (). The present invention further provides R in the general formula () or
This indicates a medical soft resin composition in which at least one of R' has a branched structure. The present invention further provides a medical soft resin composition in which the compound represented by the general formula () is isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate or 2-ethylhexyl-2-ethylhexanoate. It shows. The present invention also provides medical applications where the soft resin is an internally plasticized vinyl chloride resin, polyester, polyurethane, ethylene-vinyl acetate copolymer, or a polymer blend of polyvinyl chloride and polyurethane, ethylene polymer or caprolactone polymer. This shows a soft resin composition. The present invention further provides a medical soft resin composition in which the internally plasticized vinyl chloride resin is a urethane-vinyl chloride copolymer, a vinyl acetate-vinyl chloride copolymer, or an ethylene-vinyl acetate-vinyl chloride copolymer. It is something. The above-mentioned objects further have the general formula () RCOOR' () (where R and R' are each a chain hydrocarbon group having 3 or more carbon atoms, and The sum of the carbon numbers of R and R' is 11 to 30. achieved. The present invention also provides a medical device characterized in that it is substantially composed of a soft resin composition containing 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula (). The present invention further provides a medical device in which at least one of R or R' in the general formula () has a branched structure. The present invention further provides a medical device in which the compound represented by the general formula () is isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate or 2-ethylhexyl-2-ethylhexanoate. The present invention also provides that the soft resin is an internally plasticized vinyl chloride resin composition, polyethylene, thermoplastic polyester, polyurethane, ethylene-vinyl acetate copolymer, or a combination of polyvinyl chloride and polyurethane, ethylene polymer or caprolactone polymer. 1 illustrates a medical device that is a polymer blend. The present invention further provides a medical device in which the internally plasticized vinyl chloride resin is a urethane-vinyl chloride copolymer, a vinyl acetate-vinyl chloride copolymer, or an ethylene-vinyl acetate-vinyl chloride copolymer. . The present invention also provides a medical device characterized in that it is a blood storage container. The present invention also provides medical devices that are capable of withstanding autoclave sterilization. (Function) Therefore, the medical soft resin composition of the present invention:
In a soft resin composition that does not contain a plasticizer, the general formula () RCOOR' () (wherein R and R' are each a chain hydrocarbon group having 3 or more carbon atoms, and The biggest feature is that it is made by adding a monocarboxylic acid ester represented by the formula (the total number of carbon atoms is 11 to 30). Surprisingly, the monocarboxylic acid ester compound represented by the above general formula () has the same effect of preventing red blood cell hemolysis as di-2-ethylhexyl phthalate, and on the other hand, unlike di-2-ethylhexyl phthalate, It was found that no effect of suppressing platelet aggregation ability was observed. Furthermore, since the monocarboxylic acid ester compound represented by the above general formula () has sufficient compatibility with various soft resins, the monocarboxylic acid ester compound is incorporated into a soft resin composition that does not contain a plasticizer. By blending, it is possible to obtain a soft resin composition that has good preservability for red blood cells when it comes into contact with blood, without worrying about safety issues due to plasticizer elution. That is, when the soft resin composition comes into contact with blood, hemolysis of red blood cells is prevented by the action of the monocarboxylic acid ester compound eluted from the resin composition, while hemolysis of red blood cells such as di-2-ethylhexyl phthalate Since no substance that inhibits platelet aggregation ability is eluted during the treatment, it is highly safe for living organisms and has an excellent protective effect on red blood cells. Therefore, the medical soft resin composition of the present invention is suitable as a material for medical devices, and molded products made using the composition have excellent safety, processability, flexibility, Because of its transparency and heat resistance, it can be very effective when used as a medical device, and its effects are particularly remarkable in the case of medical devices that come into contact with body fluids such as blood. Hereinafter, the present invention will be explained in more detail based on embodiments. The soft resin used in the medical soft resin composition according to the present invention is a plasticizer (in this specification, "plasticizer" refers to an external plasticizer in a narrow sense unless otherwise specified. ), the medical soft resin composition of the present invention does not contain a plasticizer. Such soft resins include, for example, internally plasticized vinyl chloride resins, polyethylene, thermoplastic polyesters, polyurethanes, ethylene-vinyl acetate copolymers, polyvinyl chloride and polyurethanes, ethylene polymers (e.g. Elvaloy), or Examples include, but are not limited to, polymer blends with caprolactone-based polymers and the like. Internally plasticized vinyl chloride resins include, for example, urethane-vinyl chloride copolymers, vinyl acetate-vinyl chloride copolymers, and ethylene-vinyl acetate-vinyl chloride copolymers. In the system resin, the vinyl chloride monomer component and
The weight ratio with the copolymerized monomer component having a plasticizing effect is 7:3 to 3:7, more preferably 6:4.
The ratio is about 4:6. The polyethylene is preferably a low density polyethylene, preferably one having a melt index of about 0.1 to 5. Examples of thermoplastic polyester include polyethylene terephthalate film. Polyurethanes include polyester-type polyurethanes and polyether-type polyurethane elastomers, and polyether-type segmented polyurethanes are preferred. Furthermore, as for the ethylene-vinyl acetate copolymer, the weight ratio of the ethyne monomer component and the vinyl acetate monomer component is 95:5 to 70:
30, more preferably about 90:10 to 80:20. In the medical soft resin composition of the present invention, as described above, the soft resin component is not particularly limited, but preferred examples include polyurethane and ethylene-vinyl acetate copolymer. Therefore, in the medical soft composition of the present invention,
General formula () RCOOR' () (However, in the formula, R and R' each have 3 or more carbon atoms,
It is preferably a chain carbon hydrogen group of 3 to 22, most preferably 3 to 18, and the sum of the carbon numbers of R and R' is
11-30, preferably 11-21. ) is blended with a monocarboxylic acid ester. The monocarboxylic acid ester represented by the general formula () acts as a hemolysis inhibitor in the medical soft resin composition of the present invention. That is, when blood comes into contact with a product made of the medical soft resin composition of the present invention, the monocarboxylic acid ester represented by the general formula () eluted from the composition exerts a protective effect on red blood cells. It is. In the monocarboxylic acid ester represented by the general formula (), the number of carbon atoms in R and R' is 3 or more because if the chain is a chain hydrocarbon chain with less than 3 carbon atoms, the compound may become toxic. This is because it is not appropriate to incorporate it into a medical soft resin composition. Furthermore, in the monocarboxylic acid ester represented by the general formula (), R and
The reason why the sum of carbon numbers with R' is set to 11 to 30 is that if the sum of carbon numbers is less than 11, the hemolysis prevention effect will decrease, while if the sum of carbon numbers exceeds 30, compatibility with various soft resins will decrease. This is because the solubility decreases and uniform dispersion in the soft resin composition becomes difficult. In addition, in the monocarboxylic acid ester represented by the general formula (), it is preferable that at least one of the chain hydrocarbon groups R and R' has a branched structure in order to increase the compatibility with various soft resins and the effect of preventing hemolysis. preferable. Further, the chain hydrocarbon groups R and R' may be saturated or unsaturated chain hydrocarbon groups. Specifically, the monocarboxylic acid ester represented by the general formula () includes 2-ethylxylbutyrate, 2-ethylhexylisobutyrate, isoheptylvalerate, 2-ethylhexylvalerate, isoheptylpivalate, 2-ethylhexyl Pivalate, isopentylhexanoate, isohexylhexanoate, 2-ethylhexylhexanoate, isobutyl-2-ethylhexanoate, isopentyl-2-ethylhexanoate, 2-ethylhexyl-2-ethylhexanoate , isopropyl decanoate,
Isobutyl decanoate, 2-ethylhexyl decanoate, isopropyl laurate, isobutyl laurate, 2-ethylhexyl laurate,
2-ethylhexyl isolaurate, isopropyl myristate, isobutyl myristate, 2-
Ethylhexyl myristate, isopropyl palmitate, isobutyl palmitate, 2-ethylhexyl palmitate, isopropyl stearate, isobutyl stearate, 2-ethylhexyl stearate, isopropyl isostearate, isobutyl isostearate, 2-ethylhexyl isostearate, isopropyl Examples include, but are not limited to, oleate, isobutyl oleate, and 2-ethylhexyl oleate. Preferred among these compounds are isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate, and 2-ethylhexyl 2-ethylhexanoate, and most preferred is isopropyl isolaurate. The monocarboxylic acid ester represented by the general formula () is blended in the medical soft resin composition of the present invention in an amount of 5 to 35% by weight, more preferably 10 to 25% by weight. That is, if the amount of the monocarboxylic acid ester is less than 5% by weight, the effect of suppressing hemolysis of red blood cells will not be sufficient;
This is because if it exceeds this, there is a risk of deteriorating the physical properties of the soft resin composition. Furthermore, additives such as various stabilizers, lubricants, and antioxidants may be added to the medical soft resin composition of the present invention, if necessary. The medical soft resin composition of the present invention can be molded by any of the various methods used for conventional soft resin compositions, such as calendar molding, extrusion molding, blow molding, and plastisol molding. Also, depending on the type of soft resin, high frequency fusion, heat fusion, etc. can be used as an adhesion method. The medical device of the present invention has the above general formula () RCOOR' () (where R and R' each represent a chain hydrocarbon group having 3 or more carbon atoms) in a soft resin that does not contain a plasticizer. , and the sum of the carbon numbers of R and R' is 11 to 30. It has various physical properties such as flexibility, processability, flexibility, and heat resistance, and is particularly excellent in inhibiting hemolysis of red blood cells. Therefore, the medical devices of the present invention preferably include medical devices that come into contact with blood or body fluids, such as blood storage containers such as blood bags, catheters, blood transfusion sets, and blood circuits, but also the medical device packaging described above. It also includes packaging containers for drugs such as containers and tablets. Next, one embodiment of the medical device according to the present invention will be described with reference to the drawings, taking a blood bag as an example. That is, FIG. 1 shows a blood bag, in which the blood collection bag 3 made of the above-mentioned soft resin composition and equipped with a plurality of peel-tab-equipped discharge ports 1 and a connecting discharge port 2 has its peripheral portion 4 heated by high-frequency heating. Alternatively, it is heat-sealed by other heating means, and a blood collection tube 6 made of the above-mentioned soft resin composition and communicating with the internal space 5 of the blood collection bag 3 is connected. Further, a puncture needle 8 is attached to a needle base 7 provided at the tip of the blood collection tube 6, and a cap 9 is attached to this puncture needle 8.
Furthermore, a connecting tube 1 is connected to the connecting outlet 2 of the blood collection bag 3 by a connecting needle 16 at the tip.
7 is provided, and this connection tube 17 is connected via a branch pipe 15 to the inside of a first child bag 14, which is equipped with a peel tab equipped outlet 10 and is made of the above-mentioned soft resin composition and whose peripheral edge 11 is similarly heat-sealed. space 1
A connecting tube 13 made of the above-mentioned soft resin composition is connected to the connecting tubes 17 and 13, and these connecting tubes 17 and 13 are connected to each other via a branch pipe 15.
A connection tube 22 made of the above-mentioned soft resin composition is provided with an outlet 18 with a peel tab and communicates with an internal space 20 of a second sub-bag 23 made of the above-mentioned soft resin composition whose peripheral edge 19 is similarly heat-sealed. ing. This triple blood bag is capable of separating the components of blood collected in a closed system. That is, first, a predetermined amount of blood is collected into the blood collection bag 3 through the blood collection tube 6 from the puncture needle 8 inserted into the blood donor's vein. After blood collection is completed, the blood collection bag 3 is centrifuged to separate the blood into an upper layer of platelet-rich plasma and a lower layer of blood cells. Next, the platelet-rich plasma in the upper layer of the blood collection bag 3 is pushed out and transferred to the first child bag 14 through the connecting tubes 17 and 13. The first child bag 14 containing the platelet-rich plasma is further centrifuged to separate the platelet concentrate in the upper layer and the platelet-poor plasma in the lower layer. It is pushed out and transferred through the connecting tubes 13 and 22 to the second child bag 23. Blood collected in this way is separated into components by centrifugation and stored in each blood bag. Even if the blood components come into contact with the blood bags and tubes for a long time, each blood bag and tube is The soft resin composition of the present invention, which constitutes the composition, has an excellent red blood cell protection effect and does not inhibit the aggregation ability of platelets, thus enabling safe and effective component transfusion. The above explanation uses blood bags as an example, but other body fluid storage containers, catheters, blood transfusion sets,
Medical devices such as blood circuits, packaging containers for medical devices, packaging containers for drugs such as tablets, etc. are similarly suitably constructed from the above-mentioned soft resin composition. According to the present invention, the medical device is sterilized before use, and sterilization methods include ethylene oxide sterilization, autoclave sterilization, etc., and autoclave sterilization is preferably used. In autoclave sterilization, medical devices are usually treated at about 121°C for about 60 minutes, but as mentioned above, the medical devices of the present invention have sufficient heat resistance to withstand such autoclave sterilization conditions. be. (Examples) Hereinafter, the present invention will be explained in more detail based on Examples. Example 1 Ethylene-vinyl acetate copolymer (Mitsubishi Yuka Co., Ltd.)
Pellets were prepared by blending 20 parts by weight of isopropyl isolaurate with 100 parts by weight of Yucalon EVA (manufactured by Yucalon EVA) using a vented twin-screw extruder. Using this pellet, a sheet is created by extrusion molding,
A 20 ml mini blood bag was prepared by overlapping two of the obtained sheets and high-frequency sealing at a predetermined portion. Approximately 20 ml of human CPD-added concentrated red blood cell fluid (hereinafter referred to as CRC) adjusted to a hematocrit value of approximately 70% was dispensed into the bag and stored stationary at 4°C for 3 weeks. Then, the plasma hemoglobin concentration was determined by TMB.
Law (Clinical Chemistry 23 749~ (1977)
[Clin.Chem. 23 749-(1977)]).
The results are shown in Table 1. Example 2 Ethylene-vinyl acetate copolymer (Mitsubishi Yuka Co., Ltd.)
A mini blood bag was prepared in the same manner as in Example 1, except that 20 parts by weight of 2-ethylhexyl isostearate was mixed with 100 parts by weight of Yucalon EVA (manufactured by Yucalon EVA).
Changes in plasma hemoglobin concentration were examined. The results are shown in Table 1. Example 3 Ethylene-vinyl acetate copolymer (Mitsubishi Yuka Co., Ltd.)
A mini blood bag was prepared in the same manner as in Example 1, except that 20 parts by weight of 2-ethylhexyl-2-ethylhexanoate was mixed with 100 parts by weight of Yucalon EVA (manufactured by Yucalon EVA), and changes in plasma hemoglobin concentration were examined. The results are shown in Table 1. Comparative Example 1 For comparison, Example 1 was prepared using only ethylene-vinyl acetate copolymer (Yukalon EVA, manufactured by Mitsubishi Yuka Co., Ltd.).
Mini blood bags were prepared in the same manner as above, and changes in plasma hemoglobin concentration were examined. The results are shown in Table 1. Example 4 Mini blood bags were prepared in the same manner as in Example 1 except that polyurethane (Pandex, manufactured by Dainippon Ink & Chemicals Co., Ltd.) was used instead of the ethylene-vinyl acetate copolymer, and changes in plasma hemoglobin concentration were measured. I looked into it. The results are shown in Table 1. Example 5 A mini blood bag was prepared in the same manner as in Example 2 except that polyurethane (Pandex, manufactured by Dainippon Ink & Chemicals Co., Ltd.) was used instead of the ethylene-vinyl acetate copolymer, and changes in plasma hemoglobin concentration were measured. I looked into it. The results are shown in Table 1. Example 6 Mini blood bags were prepared in the same manner as in Example 3, except that polyurethane (Pandex, manufactured by Dainippon Ink & Chemicals Co., Ltd.) was used instead of the ethylene-vinyl acetate copolymer, and changes in plasma hemoglobin concentration were measured. I looked into it. The results are shown in Table 1. Comparative Example 2 For comparison, a mini-blood bag was prepared using only polyurethane (Patzdex, manufactured by Dainippon Ink & Chemicals Co., Ltd.) in the same manner as in Example 4, and changes in plasma hemoglobin concentration were examined. The results are shown in Table 1.

[Table] Example 2 Tan
As is clear from the results shown in Table 1, when the soft resin composition according to the present invention was used (Examples 1 to
In 6), it can be seen that hemolysis is suppressed to a lower level than in the case where nothing is added to the soft resin composition (Comparative Examples 1 and 2). Reference Experiment A platelet function recovery experiment was conducted using the following procedure. First, a solution of 20,000 ppm of isopropyl isolaurate in methanol (consideration example 1), 2-ethylhexyl isostearate in methanol,
A solution of 20,000 ppm dissolved in methanol (Reference Example 2), a solution of 20,000 ppm of 2-ethylhexyl-2-ethylhexanoate dissolved in methanol (Reference Example 3), di-2-ethylxyl phthalate in methanol
A solution in which 20,000 ppm was dissolved (Control Example 1) and methanol to which nothing was added (blank) were prepared. Each of these solutions was added to human platelet-poor plasma at a volume of 1/100, 2 ml of this platelet-poor plasma was added to 1 ml of human platelet-rich plasma, and Tyrode's solution (1 μM PEG ₁ 4×10 ^-3 unit/
ml, apyrase, containing 3.5 mg/ml BSA) and then incubated at 37°C for 90 minutes. After this, the platelets were washed (Legrand et al., European Journal of Biochemistry 142,
465 (1984) [Legrand et al., Eur.J.
Biochem.142, 465 (1984)]), Tyrode/BSA with apyrase 2 μg protein/ml
solution (0.2mM CaCl ₂ , 1mM MgCl ₂ , 5mM
HEPES, Tyrode's solution containing 3.5mg/ml BSA, PH
7.35), and the maximum aggregation rate for 50 μM ADP and 10 μg/ml collagen in the presence of 0.2 mg/ml fibrinogen was measured using an Agricorder (manufactured by Kyoto Daiichi Kagaku Co., Ltd.). The results are shown in Table 2.

[Table] Xanoate

[Table] Example 1 Xyl phthalate
Bra − 90.1 92.7
Link
As shown in Table 2, di-2-ethylhexyl phthalate (Control Example 1) has an inhibitory effect on recovery of platelet aggregation ability. This suggests that di-2-ethylhexyl phthalate may inhibit platelet function when it enters the body, indicating that it is not appropriate to incorporate it into medical soft resin compositions. It is. On the other hand, isopropyl isolaurate (Reference Example 1), 2-ethylhexyl isostearate (Reference Example 2), and 2-ethylhexyl-2-ethylhexanoate (Reference Example 3) did not exhibit such an inhibitory effect. This indicates that the soft resin composition of the present invention has little effect on platelets. (Effects of the Invention) As described above, the present invention provides a medical soft resin characterized in that a monocarboxylic acid ester represented by the general formula () is blended into a soft resin composition that does not contain a plasticizer. Because it is a composition, there is essentially no elution of plasticizer, so it is excellent in safety, and it suppresses hemolysis of red blood cells like the conventional soft vinyl chloride resin composition using di-2-ethylhexyl phthalate as a plasticizer. It is ideal as a material for medical equipment, especially medical equipment that comes into contact with blood, such as blood storage containers. Furthermore, when the medical soft resin composition of the present invention contains 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula (), at least one of R or R' in the general formula () is branched. More preferably, the compound represented by the general formula () is isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate or 2-ethylhexyl. -2-Ethylhexanoate, in addition, the soft resin is an internally plasticized material such as urethane-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, and ethylene-vinyl acetate-vinyl chloride copolymer. In the case of a vinyl chloride resin composition, polyethylene, thermoplastic polyester, polyurethane, ethylene-vinyl acetate copolymer, or a polymer blend of polyvinyl chloride and polyurethane, ethylene polymer, or caprolactone polymer, safety, The hemolysis inhibitory effect and other physical properties become even more excellent. The present invention is also characterized in that the soft resin composition is substantially composed of a monocarboxylic acid ester represented by the general formula () in a soft resin composition that does not contain a plasticizer. It is a medical device that is highly safe and exhibits an effect of inhibiting hemolysis against red blood cells. It can be said that it is an extremely excellent medical device with no risk of denaturing the ingredients. Furthermore, in the medical device of the present invention, the soft resin composition that substantially constitutes the medical device contains 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula ().
, or in which at least one of R or R' in the general formula () has a branched structure, more preferably represented by the general formula (). The compound is isopropyl isolaurate,
Isopropyl oleate, 2-ethylhexyl isostearate or 2-ethylhexyl-2-
In the case of ethylhexanoate, in addition, the soft resin is an internally plasticized vinyl chloride resin such as urethane-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, and ethylene-vinyl acetate-vinyl chloride copolymer. If the composition is a polyethylene, thermoplastic polyester, polyurethane, ethylene-vinyl acetate copolymer, or a polymer blend of polyvinyl chloride and polyurethane, ethylene polymer, or caprolactone polymer, safety, hemolysis inhibitory effect, The result is a medical device that is superior in other respects, such as heat resistance, transparency, and flexibility.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the medical device of the present invention. 3...Blood collection bag, 6...Blood collection tube, 1
3, 17, 22...Connection tube, 14...1st
Child Batsugu, 23...Second child Batsugu.

Claims (1)

[Claims] 1. In a soft resin composition that does not contain a plasticizer, the general formula () RCOOR' () (wherein R and R' are each a chain hydrocarbon group having 3 or more carbon atoms, and the sum of carbon numbers of R and R' is 11 to 30.) A medical soft resin composition characterized in that it contains a monocarboxylic acid ester represented by: 2. The medical soft resin composition according to claim 1, which contains 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula (). 3. The medical soft resin composition according to claim 1 or 2, wherein at least one of R or R' in the general formula () has a branched structure. 4 Claims 1 to 3, wherein the compound represented by the general formula () is isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate, or 2-ethylhexyl-2-ethylhexanoate. The medical soft resin composition according to any one of the above. 5. Claim 1, wherein the soft resin is an internally plasticized vinyl chloride resin, polyester, polyurethane, ethylene-vinyl acetate copolymer, or a polymer blend of polyvinyl chloride and polyurethane, ethylene polymer, or caprolactone polymer. The medical soft resin composition according to any one of Items 1 to 4. 6 Internally plasticized vinyl chloride resin is urethane-
The medical soft resin composition according to claim 5, which is a vinyl chloride copolymer, a vinyl acetate-vinyl chloride copolymer, or an ethylene-vinyl acetate-vinyl chloride copolymer. 7 In a soft resin composition that does not contain a plasticizer, the general formula () RCOOR' () (wherein R and R' are each a chain hydrocarbon group having 3 or more carbon atoms, and R and R' The sum of the carbon numbers is 11 to 30. 8. The medical device according to claim 7, characterized in that it is substantially composed of a soft resin composition containing 5 to 35% by weight of a monocarboxylic acid ester represented by the general formula (). . 9. The medical device according to claim 7 or 8, wherein at least one of R or R' in general formula () has a branched structure. 10 Claims 7 to 9, wherein the compound represented by the general formula () is isopropyl isolaurate, isopropyl oleate, 2-ethylhexyl isostearate, or 2-ethylhexyl-2-ethylhexanoate. Medical equipment described in any of the above. 11 The soft resin is an internally plasticized vinyl chloride resin composition, polyethylene, thermoplastic polyester,
polyurethane, ethylene-vinyl acetate copolymer,
Or the medical device according to any one of claims 7 to 10, which is a polymer blend of polyvinyl chloride and polyurethane, ethylene polymer, or caprolactone polymer. 12. Claim 11, wherein the internally plasticized vinyl chloride resin is a urethane-vinyl chloride copolymer, a vinyl acetate-vinyl chloride copolymer, or an ethylene-vinyl acetate-vinyl chloride copolymer. Medical equipment. 13. The medical device according to any one of claims 7 to 12, which is a blood storage container. 14. The medical device according to any one of claims 7 to 13, which can withstand autoclave sterilization.