JP2006117804A - Method for surface-modification of flexible plastic material and flexible plastic material having modified surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the modification of a flexible plastic material under mild, simple and short-time treating conditions on a practical level to effectively suppress the dissolution of a plasticizer in the flexible plastic material. <P>SOLUTION: The surface of a flexible plastic material such as a polyvinyl chloride resin containing a plasticizer is modified to suppress the dissolution of the plasticizer by irradiating the plastic material with energy rays such as ultraviolet rays of a wavelength of ≤365 nm at a cumulative UV quantity of 5-500 J/cm<SP>2</SP>, preferably 50-200 J/cm<SP>2</SP>. It is also preferable to irradiate the material with radiation such as γ-rays under evacuated condition at an irradiation dose of ≥50 kGy, preferably ≥200 kGy. The representative form of the flexible plastic material is tube or sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a soft plastic material having a surface modified and a surface modification method for the plastic material, and more particularly to an invention for suppressing elution of a plasticizer added to a soft plastic material.
According to the present invention, it is possible to effectively suppress the elution of the plasticizer added to the soft plastic material. Therefore, the use in the medical field, the food field, the agricultural field, etc., particularly the field where safety for the human body is required. Is effective.

  Currently, soft plastic materials such as polyvinyl chloride resins are widely used as molding materials for medical tubes and bags. In these polyvinyl chloride resins, various compounds such as phthalate esters, aliphatic polyesters, and epoxy compounds are used as plasticizers, but the plasticizing effect is high, and the transparency and workability of the resulting resin are high. Phthalate esters are most often used because they are excellent and cheap.

  Typically, plasticizers commonly referred to as phthalate esters include benzyl butyl phthalate, diethyl phthalate, di-n-propyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-phthalate Examples include n-pentyl, di-n-hexyl phthalate, mono (2-ethylhexyl) phthalate, di (2-ethylhexyl) phthalate, dicyclohexyl phthalate, diisononyl phthalate, diisodecyl phthalate, and the like.

  Conventionally, the frequency with which polyvinyl chloride products are used in the medical field etc. is very high. However, a soft plastic material such as a polyvinyl chloride resin using a plasticizer such as a phthalate ester has a problem of elution of the plasticizer. For example, when various organic solvents are passed through a tube molded from the soft plastic material, a phthalate ester as a plasticizer is extracted relatively easily. In addition, in medical bags and medical devices molded from the plastic materials, phthalate plastics can be passed through liquids such as fat-soluble pharmaceuticals and oral and enteral nutrients in addition to blood that comes into contact, depending on the conditions during use. The agent is reported to elute. Thus, there is a problem that a patient who undergoes medical practice may be exposed to a relatively large amount of a plasticizer such as phthalate ester through the medical practice.

  As described above, elution of plasticizers typified by phthalates from soft plastic materials such as polyvinyl chloride resin, which is frequently used as tubes and bags, has become a problem in medical settings. Various means for suppressing elution have been studied.

  Conventionally proposed plasticizer elution suppression means include (i) a method in which a crosslinking agent or the like is added to the plastic material and irradiated with energy rays, (ii) a method using plasma treatment such as glow discharge, (iii) ) A method of changing the plasticizer itself to a trimellitic acid type alternative plasticizer. However, these are all methods that involve material changes and methods that need to be performed in a vacuum and are extremely complicated and cannot be performed easily. Still, many polyvinyl chloride products still exist. It is currently being used with the plasticizer elution problem.

  For example, Patent Document 1 discloses a polyvinyl chloride composition that does not use a phthalate ester as a plasticizer in which special polyurethane is blended with polyvinyl chloride. This is 4 to 15 mol% of aliphatic carboxylic acid having no side chain having 6 to 12 carbon atoms and aliphatic diol having no side chain having 4 to 12 carbon atoms with respect to 100 parts by weight of polyvinyl chloride. Using polyester glycol composed of mixed diol in which an aliphatic diol having a side chain of 3 to 12 carbon atoms is used, reaction is performed at a ratio of 0.98 to 1.06 mol of the polyol component per 1 mol of the diisocyanate component. It is said that a soft polyvinyl chloride composition having low toxicity can be obtained by mixing 40 to 110 parts by weight of the polyester urethane obtained.

  However, in this case, the extractability and migration of the plasticizer to the polymer are improved, but since isocyanate is used, there is a concern about cytotoxicity due to residual isocyanate groups. In addition, since a urethane bond is introduced, the plasticizing effect is lower than that of polyester alone, and the processability is poor. Therefore, it has not been used in place of polyvinyl chloride resin plasticized with phthalates or the like.

On the other hand, several techniques for suppressing elution of a plasticizer by irradiating a polyvinyl chloride resin or the like with energy rays such as ultraviolet rays to form a crosslinked structure have been proposed.
For example, Patent Document 2 discloses that a surface of a vinyl chloride resin is irradiated with ultraviolet or visible light on a molded body such as a sheet obtained by adding a photoconductive metal compound such as zinc oxide or titanium oxide to a polyvinyl chloride resin. A technique for forming a modified coating layer by introducing intermolecular crosslinking of a resin is disclosed.

  Patent Document 3 discloses that a molded body obtained by adding an ethylene-vinyl acetate-carbon monoxide copolymer resin and a polyfunctional methacrylate to a polyvinyl chloride resin is irradiated with γ rays or electron beams. Shows a technique for introducing a crosslinked structure having a gelation rate of 50 to 90%.

  Furthermore, Patent Document 4 discloses that a polyvinyl chloride resin is irradiated with ultraviolet rays in the presence of a photosensitizer and an organic silicon compound having at least one olefinically unsaturated bond in the molecule, and then in the presence of a silanol condensation catalyst. Shows a low-temperature crosslinking method for polyvinyl chloride resin in contact with water.

  Although these technologies for crosslinking and modifying by irradiation with energy rays can modify the targeted polyvinyl chloride resin with high efficiency, basically, other than the polyvinyl chloride resin, modification by irradiation with energy rays is also possible. It is necessary to use an additive acting as a catalyst for accelerating (crosslinking), an irradiation cross-linked material or the like as an essential component, and it is necessary to newly carry out a material design accompanying a substantial material change.

In recent years, trimellitic acid esters have begun to be used as plasticizers to replace phthalic acid esters. Trimellitic acid ester has an advantage that the amount of the plasticizer eluted is smaller than that of phthalic acid ester and has low toxicity to the living body. However, trimellitic acid ester has a problem that the plasticizing efficiency itself is lower than that of phthalic acid ester, and the processability is lowered. Moreover, since it is necessary to redesign a new material by changing such a conventionally used phthalate ester plasticizer, there still remains a problem in terms of simplicity.
As described above, the plasticizer elution suppression technology proposed heretofore has hardly been implemented in practice.

Japanese Patent Publication No. 52-36896 (Claim 1). JP 58-141229 A (Claims (Claims 1 to 3)) JP-A-60-96623 (Claim 1) JP 58-115115 A (Claim 1)

The object of the present invention is to reduce the elution of the plasticizer contained in the soft plastic material at the actual use level under the conditions of relaxation, easy and short-time processing in view of the above problems of the prior art. It is to provide a method of modifying so as to be possible.
That is, the problems to be solved by the present invention are specifically (i) without material change, (ii) without changing the physical properties of the material compared to conventionally used materials, (iii) comparison It is to establish a technique for easily reducing the elution amount of a plasticizer such as a phthalate ester by means of moderate relaxation and easy means.

  At present, the present inventors have widely used polyvinyl chloride resins in various fields as a representative of the medical field, and as plasticizers used for the polyvinyl chloride resins, they have a high plasticizing effect and can be obtained. Since the transparency and processability of the resin are excellent and the cost is low, in view of the current situation that phthalates are the most realistic, they have been used without impairing such excellent material properties. In addition, the present inventors have intensively studied a method that can easily reduce the elution amount of a plasticizer without significant change of the material.

As a result, in order to modify the surface characteristics of the soft plastic material so as to reduce the elution amount of the plasticizer, the present inventors have performed irradiation with energy rays (ultraviolet irradiation, radiation) performed under specific conditions. As a result, the present invention was completed.
That is, according to the present invention, the following method for modifying the surface of a soft plastic material is provided.

(Surface modification method)
[1] (corresponding to Examples 1 and 2)
By irradiating a soft plastic material containing a plasticizer with ultraviolet light having a wavelength of 365 nm or less under the condition of an ultraviolet integrated light quantity of 5 to 500 J / cm ² , the surface of the plastic material is modified and elution of the plasticizer is suppressed. A method for modifying the surface of a soft plastic material.

[2] (corresponding to Examples 1 and 2)
The surface modification method for a soft plastic material according to the item [1], wherein ultraviolet rays having a wavelength of 365 nm or less are irradiated under the condition of an accumulated ultraviolet light amount of 50 to 200 J / cm ² .

[3] (corresponding to Example 3)
By irradiating a soft plastic material containing a plasticizer with radiation under a reduced pressure condition of 30 Torr or less under an irradiation dose of 50 kGy or more, the surface of the plastic material is modified to suppress elution of the plasticizer. A method for surface modification of a soft plastic material.

[4] (corresponding to Example 3)
The surface modification method for a soft plastic material according to the item [3], wherein the radiation is irradiated under a reduced pressure condition of 30 Torr or less under a condition where the irradiation dose is 200 kGy or more.

[5] (corresponding to Example 4)
By irradiating a soft plastic material containing a plasticizer with radiation in the presence of an oxidizing agent under conditions of an irradiation dose of 1 kGy or more, the surface of the plastic material is modified, and elution of the plasticizer is suppressed. A method for modifying the surface of a soft plastic material.

[6] (corresponding to Examples 1 and 2)
The method for modifying the surface of a soft plastic material according to any one of [1] to [5], wherein the soft plastic material is a tube or a sheet.

(Surface-modified soft plastic material)
[7] (corresponding to Example 3)
A soft plastic material containing a plasticizer and containing neither an additive intended for modification by ultraviolet irradiation nor an irradiation cross-linking material is irradiated with ultraviolet light having a wavelength of 365 nm or less, and an ultraviolet integrated light quantity of 5 to 500 J / cm ^2. A soft plastic material with a modified surface characterized by modifying the surface of the plastic material by irradiating under the above conditions and suppressing elution of the plasticizer.

[8] (corresponding to Example 3)
The surface of the plastic material is modified by irradiating ultraviolet rays having a wavelength of 365 nm or less under the condition of an ultraviolet integrated light quantity of 50 to 200 J / cm ² , and the surface of the plastic material is suppressed. The soft plastic material according to item [7].

[9]
By irradiating a soft plastic material containing a plasticizer and containing neither an additive intended for modification by radiation irradiation nor an irradiation cross-linked material with radiation at a dose of 1 kGy or more, A soft plastic material with a modified surface characterized by modifying the surface of the plastic material and suppressing elution of the plasticizer.

[10]
The soft plastic material according to any one of items [7] to [9], wherein the soft plastic material is a tube or a sheet.

  According to the present invention, when a soft plastic material is modified by irradiating it with energy rays, in the prior art, addition is essential, for example, a photoconductive metal compound such as zinc oxide or titanium oxide (Patent Document 2). ), Multifunctional methacrylate (Patent Document 3), photosensitizer and organic silicon compound having at least one olefinically unsaturated bond in the molecule (Patent Document 4), etc. The surface of the soft plastic material is modified only by irradiating energy rays (ultraviolet rays, radiation) under specific conditions without any additives or irradiation cross-linking materials intended for modification by The superior physical properties of the material itself can be achieved without changing the material or performing complicated processing steps on conventional soft plastic products. While retained, only the elution of the plasticizer, it is possible to suppress efficiently.

Hereinafter, the present invention will be described in detail.
(Soft plastic material)
The soft plastic material in the present invention is a polymer material to which a plasticizer is added. Examples include, but are not limited to, polyvinyl chloride resin, polylactic acid, polyglycolic acid, (meth) acrylic resin, and cellulose acetate. These may be used alone or in combination.

  Of these, polyvinyl chloride resin is most preferred. As a polyvinyl chloride resin, not only a polyvinyl chloride homopolymer, but mainly polyvinyl chloride and other monomers such as (meth) acrylic acid ester, α-olefin, vinyl acetate, styrene, vinyl ether, etc. A binary or ternary copolymer may be used (hereinafter, this may be referred to as “polyvinyl chloride material”).

(Plasticizer)
In the present invention, as the plasticizer blended in the soft plastic, any conventionally known and widely used plasticizer is preferably used. As the plasticizer, an appropriate one corresponding to the resin is selected and used.

  For example, as a plasticizer for a polyvinyl chloride material, for example, dimethyl phthalate, diethyl phthalate, diisopropyl phthalate, di-n-propyl phthalate, dibutyl phthalate, dihexyl phthalate, di-2-ethylhexyl phthalate (DEHP), di-n-octyl Phthalates such as phthalate, diisooctyl phthalate, diheptyl phthalate, didecyl phthalate, butyl benzyl phthalate, diphenyl phthalate, ditridecyl phthalate; tri-2-ethylhexyl trimellitate, tributyl trimellitate, trioctyl trimellitate Trimellitic acid esters such as tate; dioctyl adipate, di-n-butyl adipate, di-2-ethylhexyl adipate, dioctyl azelate, dioctyl sebacate, etc. Aliphatic polybasic acid esters; phosphate esters such as tricresyl phosphate, trixylenyl phosphate, monooctyl diphenyl phosphate, monobutyl disilenyl phosphate, trioctyl phosphate; tributyl acetyl citrate Citric acid esters such as trioctyl acetyl citrate and tributyl citrate, and succinates are preferable. These may be used alone or in combination of two or more.

  The compounding quantity with respect to the soft resin of these plasticizers is 0.1-60 mass% normally, Preferably it is 1-50 mass%, More preferably, it is about 5-40 mass%.

  In addition, it should be noted that the soft plastic material such as the polyvinyl chloride resin of the present invention is a photoconductive metal compound such as zinc oxide or titanium oxide in Patent Document 2, for example, in addition to the above-mentioned general-purpose plasticizer, Irradiation of energy rays (ultraviolet irradiation, radiation) such as polyfunctional methacrylate in Patent Document 3 and photosensitizer and organic silicon compound having at least one olefinically unsaturated bond in the molecule in Patent Document 4 This means that it does not contain any special additives or irradiation cross-linked materials for the purpose of modification, and of course there is no need to add them.

(Other additives)
The soft plastic material in the present invention has a stabilizer, a nucleating agent, a flame retardant, a filler, a foaming agent, a lubricant, a pigment, an antioxidant, an ultraviolet absorber, as long as the effects of the present invention are not significantly impaired. A surfactant or the like and various additives usually added to the polymer material may be added.

(Molded product)
In the present invention, the soft plastic material subjected to the surface modification treatment is subjected to energy beam irradiation treatment as a molded product having an appropriate form, but the molded product is not limited in its shape. For example, fiber, woven, net, non-woven, cloth, film, sheet, tube, tape, tubular, cable, pipe, hose, round bar, square bar, drum, roller, circle Ring shape, disk shape, hollow container shape, thick plate shape, thin plate shape, corrugated plate shape, spherical shape, cord shape, covering shape such as electric wire, box shape, etc. Can be used.

(Energy rays)
In the present invention, a soft plastic material is irradiated with energy rays such as ultraviolet rays and radiation (X rays, α rays, β rays, γ rays, neutron rays) under specific conditions to modify the surface. Ultraviolet rays and radiation are particularly preferable, but are not limited to these as long as they have a certain amount of irradiation energy and can modify the material surface.

(UV irradiation)
In the case of ultraviolet irradiation, it is desirable to irradiate ultraviolet rays with a wavelength of 365 nm or less and 200 nm or more, preferably with a wavelength of 320 nm or less and 240 nm or more under the condition of an ultraviolet integrated light quantity of 5 to 500 J / cm ² , preferably 50 to 200 J / cm ^2. .

The fact that the elution amount of the plasticizer is effectively suppressed by irradiating under these conditions is apparent from, for example, the relationship between the integrated light amount and the irradiation (treatment) period shown in Table 1 of Examples below.
In addition, as a suitable example of ultraviolet irradiation conditions, the conditions of wavelength 254nm and ultraviolet rays integrated light quantity 100J / cm < ² > are mentioned at room temperature, for example.

(Radiation irradiation)
In the case of irradiation with X-rays, α-rays, β-rays, γ-rays, neutrons, and the like, it is preferable to perform irradiation with an irradiation dose of 50 kGy or more, preferably 200 kGy or more under reduced pressure conditions (for example, Example 3, Table below). 6), and in the presence of an oxidizing agent such as ozone, it is desirable to irradiate 1 kGy or more, preferably 10 kGy or more (for example, see Example 4 and Table 9 below).
The reduced pressure condition is 30 Torr or less, preferably 10 Torr or less.

  In the case of irradiation, irradiation can be performed under room temperature and reduced pressure conditions, or irradiation can be performed in the presence of room temperature and an oxidizing agent (for example, ozone). (As a reminder, Gy is the SI unit of the absorbed dose of ionizing radiation, and the absorbed dose when 1 J of energy per kg is applied to the plastic material is 1 Gy.)

(Reaction field during irradiation, etc.)
The reaction field at the time of irradiation with energy rays (ultraviolet rays, radiation) in the present invention is basically possible in the atmosphere, but in order to prevent the oxidation of the soft plastic material, argon, neon, helium, nitrogen, etc. It is desirable to carry out in an inert gas atmosphere in a container filled with an inert gas.

  The wavelength of energy rays (ultraviolet rays and radiation) used in the present invention is inconvenient because irradiation of a too short energy ray tends to cause a decrease in material strength, such as destruction of the material structure. Energy beam irradiation is inconvenient because a reaction for surface modification hardly occurs.

  As shown in the examples below, irradiation with shorter wavelength energy rays, such as γ rays, can be modified not only in the vicinity of the irradiated surface of the plastic material, but also in the deep part of the material, By irradiation with a long wavelength ultraviolet ray or the like, only the surface of the material can be modified. When practicing the present invention, it is desirable to select appropriate conditions depending on the application, taking into consideration the characteristics of the energy rays employed.

  Hereinafter, the present invention will be described by way of examples. However, these are merely examples of embodiments, and the technical scope of the present invention is not construed as being limited thereto. Unless otherwise specified, “%” means “% by mass”.

[Example 1]
(1) Polyvinyl chloride resin blood bag sheet (manufactured by Terumo Corporation, hereinafter referred to as “PVC sheet”) (1 × 3 cm, thickness 0.4 mm, phthalate ester (hereinafter referred to as “DEHP”) as a plasticizer. Were irradiated using an ultraviolet germicidal lamp. That is, ultraviolet rays having a wavelength of 254 nm were irradiated from the embossed surface on the outside of the bag over a treatment period of 1 week, 2 weeks, 1 month, 2 months, and 3 months under the condition of an ultraviolet intensity of 52.5 μW / cm ² . .

(2) Put each PVC sheet (UV-irradiated specimen) in a glass test tube with a screw cap, add 5 ml of Sandy Mün injection (cyclosporine: Novartis Pharma), which is a fat-soluble drug at the actual use concentration, and at room temperature The plasticizer was extracted by shaking for 1 hour. The plasticizer was extracted with diethyl ether from the shaking solution containing the eluted plasticizer.

The obtained extract was analyzed by a GC / MS measuring device, and the elution amount of the plasticizer was investigated. Moreover, each PVC sheet irradiated with ultraviolet rays was evaluated and analyzed by FT-IR, ESCA, and a tensile test.
Table 1 shows the plasticizer (DEHP) elution test results from the PVC sheet in the case of the UV irradiation specimen, that is, the correlation between the UV treatment time (UV irradiation time), the UV integrated light amount, and the plasticizer elution amount.

(3) Blank In Example 1, the same test as in the example was performed except that visible light was irradiated instead of ultraviolet light. The obtained specimen (visible light-irradiated specimen) was used as a reference for evaluation in Example 1 (blank).
Table 2 shows the plasticizer (DEHP) elution test results from the PVC sheet in the case of visible light irradiation, that is, the correlation between the visible light irradiation time and the elution amount.

  From Tables 1 and 2, the following can be said. That is, in the sample irradiated with visible light, although the DEHP elution amount was slightly decreased by irradiation for 2 months, no significant change in elution behavior was observed. In contrast, in the case of the UV-irradiated specimen, the DEHP elution amount decreased with time from immediately after the irradiation, and was reduced by half compared to unirradiated (negative control sample) by the treatment for up to 1 month. However, further irradiation did not affect the DEHP elution amount, and no further decrease in DEHP elution amount was observed.

(4) The DEHP content in each PVC sheet in the UV irradiation specimen and the visible light irradiation specimen was measured. That is, 0.02 g of the finely cut PVC sheet was accurately weighed and completely dissolved in 20 ml of THF. 0.1 ml of the same solution was collected and diluted 100 times with diethyl ether. 0.1 ml of the same dilution was collected, 1 ml of a 500 ng / ml DEHP-d ₄ diethyl ether solution and 8.9 ml of diethyl ether were added, and then the DEHP concentration was measured using GC / MS. The results (PVC sheet plasticizer (DEHP) content test results (mass / mass%)) are shown in Table 3.

As can be seen in Table 3, the DEHP content of the UV-irradiated specimen group tended to decrease slightly over time as the treatment period was extended. However, the decrease rate of DEHP content of the PVC sheet irradiated with ultraviolet rays for 1 month is about 7%, and it is not a change rate corresponding to nearly 50%, which is the decrease rate of DEHP elution from the PVC sheet subjected to the same treatment. It was. From this, it was shown that the cause of the decrease in the DEHP elution amount from the PVC sheet subjected to the treatment was not due to the decrease in the DEHP content of the PVC sheet due to the treatment.
(5) Further, Table 4 shows the tensile test results (maximum load measurement / N) of the ultraviolet irradiation specimen and the visible light irradiation specimen.

As is apparent from Table 4, no change in physical properties was observed in both the visible light irradiation specimen and the ultraviolet irradiation specimen.
(6) On the other hand, as a result of structural analysis by FT-IR, a peak derived from C-Cl stretching vibration, which is a characteristic absorption of PVC molecules, is observed in the vicinity of 635 cm ^-1 in an untreated PVC sheet. peak derived from aromatic CH bending vibration of DEHP molecules was detected around 742cm ^-1 and 1720 cm ^-1, respectively.

Thus, it was confirmed that these peaks gradually changed to broad as the ultraviolet irradiation time was extended. On the other hand, the peak in the FT-IR of the non-irradiated surface of the visible light irradiation specimen and the ultraviolet irradiation specimen was the same as that of the untreated PVC sheet, and no change was observed.
From the above, it was confirmed that some structural change occurred on the PVC surface by ultraviolet irradiation, suggesting that the change occurred only on the material surface.

(7) Further, as a result of elemental composition analysis on the surface of the PVC sheet by ESCA, carbon, oxygen, chlorine and silicon were detected as the composition elements on the surface of the PVC sheet. In the surface element composition of this PVC sheet, with the extension of the ultraviolet irradiation period, the chlorine content tended to decrease over time and the oxygen content tended to increase.

From this, it was confirmed that dehydrochlorination and oxidation proceeded simultaneously on the surface of the PVC sheet as the UV irradiation time was extended.
In contrast, in the sample irradiated with visible light, the elemental element composition ratio on the sample surface was kept constant, and no change was observed. Moreover, it was confirmed that the non-irradiated surface of the UV-irradiated specimen slightly fluctuated by irradiation for one week to one month, but the element composition ratio of the sample surface treated for 2 months and 3 months was not irradiated (negative control). There was no significant change compared to the sample.

From the above results, it is possible to introduce a modification with dehydrochlorination and oxidation on the very surface layer of the irradiated surface by irradiating ultraviolet rays of 254 nm (ultraviolet intensity 52.5 μW / cm ² ) for one month. It was shown that elution of the plasticizer can be suppressed.

[Example 2]
(1) Polyvinyl chloride resin infusion tube (prototype, manufactured by Kawasumi Chemical Industry Co., Ltd., hereinafter referred to as “PVC tube”) (outside diameter 3.4 mm, inside diameter 2.13 mm, containing DEHP as a plasticizer) Were subjected to ultraviolet treatment. That is, using a UV germicidal lamp, UV light of 254 nm was irradiated on the outer surface of the PVC tube over a period of 2 weeks under the condition of a UV intensity of 52.5 μW / cm ² to obtain a sample irradiated for 2 weeks.
In addition, a sample irradiated with visible light under the same conditions (sample irradiated with visible light for 2 weeks) was prepared as a blank.

(2) Each PVC tube is filled with Sandy Mün injection (cyclosporin: Novartis Pharma), which is a fat-soluble drug at the actual use concentration (filled drug: tube length: 8 cm, inner volume: 0.285 cm ³ , inner surface area: 5) .35 cm ² ) and extracted with shaking at room temperature for 1 hour. The plasticizer was extracted with diethyl ether from the shaking solution containing the eluted plasticizer.
The obtained extract was analyzed by GC / MS measurement, and the elution amount of the plasticizer was measured. The results are shown in Table 5 as the amount of plasticizer (DEHP) eluted from the PVC tube (μg / ml).

  As a result of evaluating the DEHP elution amount of the specimen irradiated with ultraviolet rays on the outer surface of the PVC tube, as shown in Table 5, the DEHP elution amount from the inner surface of the PVC tube is not affected by the ultraviolet ray irradiation and is found in the ultraviolet ray irradiated PVC sheet. No decrease in elution amount was observed.

  Comprehensively judging the results of Examples 1 and 2 above, it can be confirmed that the introduction of the modification by ultraviolet irradiation under the conditions in the present invention is a modification of the surface of the material. Therefore, in this invention, it turns out that elution of a plasticizer can be suppressed, maintaining the physical property of the soft plastic material which is a product substantially.

  Moreover, in Example 1, although the result by which the elution of the plasticizer from a PVC sheet was suppressed to about 1/2 was obtained, in the said Example 1, the ultraviolet-ray is irradiated only to the single side | surface of a PVC sheet. It is necessary to note that. That is, the elution of the plasticizer from the PVC sheet is presumed to be substantially from the non-irradiated surface. Thus, in this example, it can be determined that the DEHP elution from the UV irradiation surface was almost completely suppressed, and as a result, the DEHP elution from the sheet was reduced by half.

Example 3
(1) Polyvinyl chloride resin infusion tube (prototype, manufactured by Kawasumi Chemical Industry Co., Ltd., hereinafter referred to as “PVC tube”) (outside diameter 3.4 mm, inside diameter 2.13 mm, containing DEHP as a plasticizer) The outer surface of the PVC tube is irradiated with γ rays ( ⁶⁰ CO) at an intensity of 10 kGy / h for 5 hours, 12 hours, 24 hours, and 48 hours under a reduced pressure condition of 10 Torr. Samples for each treatment time were obtained.
A specimen irradiated with visible light under the same conditions was prepared as a blank.

(2) Each PVC tube is filled with Sandy Mün injection (cyclosporin: Novartis Pharma), which is a fat-soluble drug at the actual use concentration (filled drug: tube length: 8 cm, inner volume: 0.285 cm ³ , inner surface area: 5) .35 cm ² ) and extracted with shaking at room temperature for 1 hour. The plasticizer was extracted with diethyl ether from the shaking solution containing the eluted plasticizer.
The obtained extract was analyzed by GC / MS measurement, and the elution amount of the plasticizer was measured. Table 6 shows the results of the plasticizer (DEHP) elution test from the PVC tube in the case of radiation irradiation, that is, the correlation between the γ-ray irradiation time (treatment time), the γ-ray irradiation dose, and the DEHP elution amount. Table 7 shows the correlation between the visible light irradiation time and the elution amount as a result of the plasticizer (DEHP) elution test from the PVC tube in the case of a blank.

  In the above test, the amount of DEHP eluted from the inner surface of the PVC tube decreased with time in the gamma-irradiated specimen under reduced pressure over time immediately after irradiation. In Example 3, evaluation was carried out up to 480 kGy, but at that time, the elution amount of the plasticizer was suppressed by about 46%.

As mentioned in the results of Example 2, ultraviolet irradiation on the outer surface of the tube did not inhibit the plasticizer from the inner surface of the tube. On the other hand, the elution of the plasticizer from the inner surface of the tube could be suppressed by γ-ray irradiation on the outer surface of the tube. This result is presumed to be caused by a difference in characteristics between ultraviolet rays and γ rays, that is, a difference in material permeability.
(3) Further, Table 8 shows the results of a tensile test (breaking strength measurement) of the PVC tube.

表８より明らかなように、減圧条件下でγ線を照射した検体であるチューブに、顕著な物性の変化は認められなかった。

As is apparent from Table 8, no significant change in physical properties was observed in the tube, which was a specimen irradiated with γ rays under reduced pressure conditions.

Example 4
(1) Polyvinyl chloride resin infusion tube (prototype, manufactured by Kawasumi Chemical Industry Co., Ltd., hereinafter referred to as “PVC tube”) (outside diameter 3.4 mm, inside diameter 2.13 mm, containing DEHP as a plasticizer) ) On the outer surface of the PVC tube at room temperature under the condition of an ozone partial pressure of 200 Torr as an oxidizing agent, γ rays ( ⁶⁰ CO) at an intensity of 10 kGy / h for 1 hour, 2 hours, 6 hours For 12 hours to obtain specimens for each treatment time.
A specimen irradiated with visible light under the same conditions was prepared as a blank.

(2) Each PVC tube is filled with Sandy Mün injection (cyclosporin: Novartis Pharma), which is a fat-soluble drug at the actual use concentration (filled drug: tube length: 8 cm, inner volume: 0.285 cm ³ , inner surface area: 5) .35 cm ² ) and extracted with shaking at room temperature for 1 hour. The plasticizer was extracted with diethyl ether from the shaking solution containing the eluted plasticizer.

The obtained extract was analyzed by GC / MS measurement, and the elution amount of the plasticizer was measured. The results are shown in Table 9. Plasticizer (DEHP) dissolution test results from PVC sheets in the case of γ-irradiated specimens, that is, correlation of γ-ray treatment time (γ-ray irradiation time), γ-ray irradiation dose, and plasticizer elution amount Indicates.
Table 10 shows the correlation between the visible light irradiation time and the elution amount as a plasticizer (DEHP) elution test result from the PVC tube in the case of a blank.

図９に示すように、酸化剤（Ｏ₃）存在下でPVCチューブ外面にγ線を照射した場合、PVCチューブ内面からのDEHP溶出量は、減圧条件下においてγ線を照射する場合よりも、より低照射線量で抑制されることが確認された。これは酸化剤存在下では、γ線照射に伴うPVCチューブ材料の改質が、一層効率よく進行したことに起因した結果と推定される。
（３）さらに表１１には、PVCチューブの引張試験（破断強度測定）の結果を示した。

As shown in FIG. 9, when the outer surface of the PVC tube is irradiated with γ rays in the presence of an oxidizing agent (O ₃ ), the DEHP elution amount from the inner surface of the PVC tube is larger than that when γ rays are irradiated under reduced pressure conditions. It was confirmed that it was suppressed at a lower irradiation dose. This is presumably due to the fact that the reforming of the PVC tube material accompanying the γ-ray irradiation proceeded more efficiently in the presence of the oxidizing agent.
(3) Further, Table 11 shows the results of a tensile test (breaking strength measurement) of the PVC tube.

  From Table 11, a slight decrease in the breaking strength (about 10% at 480 kGy) was observed in the tube that was a specimen irradiated with γ rays in the presence of an oxidizing agent. From this result, in the presence of an oxidizing agent, it is expected that the material modification accompanying γ-ray irradiation will proceed efficiently and at the same time, more main chain breaks will occur due to gamma-ray irradiation.

  According to the present invention, a soft plastic resin such as a polyvinyl chloride resin containing a plasticizer such as a phthalate ester which is conventionally used is irradiated with a specific energy ray to modify the surface thereof. This is a relatively relaxed and easy means that can easily reduce the elution of plasticizer without complicated material changes and without changing the physical properties of the material. large.

Claims (10)

By irradiating a soft plastic material containing a plasticizer with ultraviolet light having a wavelength of 365 nm or less under the condition of an ultraviolet integrated light quantity of 5 to 500 J / cm ² , the surface of the plastic material is modified and elution of the plasticizer is suppressed. A method for modifying the surface of a soft plastic material. Surface modification method of a soft plastic material according to claim 1, ultraviolet light having a wavelength of 365 nm, it is irradiated under the condition of UV accumulated light amount 50~200J / cm ^2.   By irradiating a soft plastic material containing a plasticizer with radiation under a reduced pressure condition of 30 Torr or less under an irradiation dose of 50 kGy or more, the surface of the plastic material is modified to suppress elution of the plasticizer. A method for surface modification of a soft plastic material.   The surface modification method for a soft plastic material according to claim 3, wherein the radiation is irradiated under a reduced pressure condition of 30 Torr or less under a condition of an irradiation dose of 200 kGy or more.   By irradiating a soft plastic material containing a plasticizer with radiation in the presence of an oxidizing agent under conditions of an irradiation dose of 1 kGy or more, the surface of the plastic material is modified, and elution of the plasticizer is suppressed. A method for modifying the surface of a soft plastic material.   The surface modification method for a soft plastic material according to any one of claims 1 to 5, wherein the soft plastic material is a tube or a sheet. A soft plastic material containing a plasticizer and containing neither an additive intended for modification by ultraviolet irradiation nor an irradiation cross-linking material is irradiated with ultraviolet light having a wavelength of 365 nm or less, and an ultraviolet integrated light quantity of 5 to 500 J / cm ^2. A soft plastic material with a modified surface characterized by modifying the surface of the plastic material by irradiating under the above conditions and suppressing elution of the plasticizer. The surface of the plastic material is modified by irradiating ultraviolet rays having a wavelength of 365 nm or less under the condition of an ultraviolet integrated light quantity of 50 to 200 J / cm ² , and the surface of the plastic material is suppressed. The soft plastic material according to claim 7.   By irradiating a soft plastic material containing a plasticizer and containing neither an additive intended for modification by radiation irradiation nor an irradiation cross-linked material with radiation at a dose of 1 kGy or more, A soft plastic material with a modified surface characterized by modifying the surface of the plastic material and suppressing elution of the plasticizer.   The soft plastic material according to any one of claims 7 to 9, wherein the soft plastic material is a tube or a sheet.