JP2006022403A - Method for inhibiting organic compound from adsorbing onto surface of article molded from synthetic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for inhibiting an organic compound from adsorbing onto the surface of an article molded from a synthetic resin. <P>SOLUTION: The method for inhibiting the organic compound from adsorbing onto the surface of the article molded from the synthetic resin includes forming a thin layer of a metal, silicon or oxide thereof on the surface of the article molded from the synthetic resin, with a thin-film-forming technology using plasma. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a synthetic resin molding of an organic compound characterized in that a thin film layer of metal, silicon or oxide thereof is formed on the surface of a synthetic resin molding such as a container by a thin film forming technique using plasma. It is related with the adsorption | suction suppression method.

 Synthetic resins are widely used as materials for various molded products such as containers because they are easy to mold, have excellent impact resistance, and are lightweight and safe. However, since the synthetic resin molding has the property that the organic compound is adsorbed on the surface thereof, there are various restrictions in use in which the organic compound is in direct contact. Therefore, attempts have been made to suppress the adsorption of organic compounds by modifying the surface of the synthetic resin.

 As one of them, a plasma etching technique is known. This technology is characterized by homogenizing the surface of the synthetic resin by plasma treatment, but the surface structure of the synthetic resin can be modified even at low temperatures. It is described that plasma irradiation is performed on a united plate in an argon gas atmosphere, thereby improving the hydrophilicity of the surface and suppressing the adsorption of insulin, and Non-Patent Document 2 describes a polymethacrylate plate. It is described that when plasma treatment is performed in an argon gas atmosphere to make it hydrophilic, it is possible to suppress adsorption of proteins such as lysozyme, albumin, and γ-globulin in artificial tears to the surface of the polymethacrylate plate.

 On the other hand, as a method of forming a metal or metal oxide thin film on the surface of a synthetic resin molding by a thin film formation technique using plasma, sputtering, ion plating, plasma chemical vapor deposition, arc ion plating, It is known that a resin container in which a thin film of metal or metal oxide is formed using these techniques has excellent permeation-blocking properties for gases such as oxygen.

For example, Patent Document 1 discloses that the gas permeability is reduced by forming a SiO ₂ film on the surface of a synthetic resin container such as polyethylene terephthalate (PET) or polyethylene (PE) using a special ionization coating method. It describes that the prevention of oxidation of the material is attempted. Patent Document 2 discloses that gas barrier properties such as oxygen are enhanced by plasma chemical vapor-depositing a ceramic thin film layer mainly composed of silicon oxide on the inner surface or outer surface of a plastic molded article made of an ethylene-polypropylene random copolymer. Is described. The above prior art documents are intended to protect the contents by blocking the invasion of gas such as oxygen from the outside of the container into the container, using a thin film forming technique using plasma. Needless to say, there is no description on the suppression of adsorption of organic compounds by forming a thin film layer, and no suggestion has been made.
JP-A-60-2443 JP 2001-261866 A Pharmaceutical Journal 119 (12) 929-935,1999 Chem. Pharm. Bull. 42 (9) 1896-1901, 1994

 If the adsorption of the organic compound to the surface of the synthetic resin molding can be suppressed, the synthetic resin can be used more effectively. One of the methods is a plasma etching technique described in the background art. Although the plasma etching technique is a simple and useful method, radicals generated at the cross-linked sites and graft sites on the surface of synthetic resin molded products may cause secondary reactions with oxygen in the air, and new organic Development of a method for inhibiting the adsorption of compounds has been desired.

  Synthetic resins are used in various applications, and are also used in aqueous liquid containers such as eye drops containers. In ophthalmic containers, if organic compounds such as drugs or preservatives in eye drops stored in the container are adsorbed on the inner surface of the container, the concentration of the organic compounds in the eye drops changes, and quality assurance cannot be achieved. Therefore, it is an important problem to suppress a decrease in the content of the organic compound in the ophthalmic solution.

  The present inventor has intensively studied to solve the above-described problems. As a result of forming a thin film layer of metal, silicon, or an oxide thereof on a synthetic resin molding by a thin film formation technique using plasma, It has been found that adsorption of organic compounds can be effectively suppressed, and has led to the present invention.

That is, the present invention
(1) A method for suppressing adsorption of an organic compound to a synthetic resin molding, comprising forming a thin film layer of metal, silicon or an oxide thereof on the surface of the synthetic resin molding by a thin film forming technique using plasma. ,
(2) A method for suppressing the adsorption of an organic compound on the inner surface of a container, characterized in that a thin film layer of metal, silicon or an oxide thereof is formed on the inner surface of the synthetic resin container by a thin film forming technique using plasma,
(3) The method according to (1) to (2), wherein the synthetic resin is a polyolefin resin, a polystyrene resin or a polyester resin,
(4) The method according to (3) above, wherein the polyolefin resin is a polyethylene resin, a polypropylene resin or a polyethylene terephthalate resin,
(5) The method according to (1) to (2), wherein the thin film formation technique using plasma is a sputtering technique,
(6) The method according to (1) to (2) above, wherein the metal, silicon or oxide thereof is Ti, Ag, TiO ₂ or SiO ₂ ,
(7) The method according to (1) to (2) before the film thickness of the thin film layer is 1 μm or less,
(8) The method according to (1) to (2) above, wherein the organic compound is an additive acceptable for a drug or a pharmaceutical product, food or beverage,
(9) The method according to (2), wherein the synthetic resin container is an aqueous liquid container,
(10) The method according to (9), wherein the aqueous liquid preparation container is an eye drop container or a plastic bottle,
(11) A synthetic resin molded article in which adsorption of an organic compound is suppressed by the method described in (1) above,
(12) A synthetic resin container in which adsorption of an organic compound is suppressed by the method described in (2) above,
(13) Suppressing adsorption of organic compounds to synthetic resin moldings by forming a thin film layer of metal, silicon or their oxides on the surface of synthetic resin moldings by means of thin film formation technology using plasma Excellent synthetic resin moldings,
(14) A synthetic resin container excellent in suppressing adsorption of organic compounds to the inner surface of the container, characterized in that a thin film layer of metal, silicon or oxide thereof is formed on the inner surface of the container by a thin film forming technique using plasma. ,
About.

 In the present invention, the type of the synthetic resin is not particularly limited, and examples thereof include polyolefin resin, polystyrene resin, polyester resin, and the like, and polyolefin resin is preferable. Examples of the polyolefin resin include polyethylene resin (PE), polypropylene resin (PP), polyethylene terephthalate resin (PET), polyvinyl chloride resin (PVC), and more preferably polyethylene resin (PE) and polypropylene resin (PP ), Polyethylene terephthalate resin (PET). These resins may be homopolymers or copolymers.

The synthetic resin container of the present invention is not particularly limited as long as it is a container that can store an aqueous liquid, and examples thereof include eye drop containers and plastic bottles. In addition, the method for suppressing adsorption of organic compounds to synthetic resin moldings by the thin film formation technology using the plasma of the present invention is also suitable for suppressing the adsorption of trace amounts of organic compounds in aqueous liquids. It can also be used for technical biochips.
In the present invention, the thin film formation technique using plasma is a technique for forming a thin film layer of metal, silicon or oxide thereof on the surface of a synthetic resin molding by plasma irradiation, for example, sputtering (deposition) described in the background art. Technologies for Films and Coatings, NOYES PUBLICATIONS, 1982, pp170-243, NOYES PUBLICATIONS, 1990, pp160-182, etc., ion plating (HANDBOOK OF PLASMA PROCESSING TECHNOLOGY, NOYES PUBLICATIONS, 1990, pp338-355), plasma chemical vapor Growth methods (Deposition Technologies for Films and Coatings, NOYES PUBLICATIONS, 1982, pp365-384), arc ion plating (HANDBOOK OF PLASMA PROCESSING TECHNOLOGY, NOYES PUBLICATIONS, 1990, pp419-446), hollow cathode deposition (HANDBOOK OF PLASMA PROCESSING TECHNOLOGY , NOYES PUBLICATIONS, 1990, pp 308-335), and more preferably sputtering.

Examples of the metal, silicon, or oxide thereof include Ti, Si, Ta, Al, Ni, Cr, Ag, Sn, Hf, Nb, TiO ₂ , SiO ₂ , SiO, and Al ₂ O ₃ . More preferred are Ti, Ag, TiO ₂ and SiO ₂ .

  The film thickness (average film thickness) of the metal, silicon, or oxide thereof is preferably 1 μm or less, more preferably 0.1 to 500 nm, and most preferably 1 to 100 nm. Even if such a thin layer is thin, the adsorption of the organic compound to the surface of the synthetic resin molding is effectively suppressed.

Further, by repeating the thin film formation using plasma, a multilayer metal, silicon, or oxide thin film layer thereof can be formed, thereby further improving the adsorption suppression effect. As the thin film layer composed of two layers, for example, an Ag layer formed by vapor deposition on a TiO ₂ layer can be mentioned.

  In the synthetic resin container according to the present invention, the organic compound is usually stored in the form of a solution or a suspension. Organic compounds adsorbed on the inner surface of the container include, for example, vitamins such as vitamin E, local anesthetics such as dibucaine hydrochloride, steroids such as fluorometholone, betamethasone and triamcinolone, prostaglandin derivatives such as latanoprost, cyclosporine, Examples of the additives include drugs such as lysozyme, albumin and γ-globulin, such as peptides and proteins, and preservatives and surfactants acceptable for pharmaceuticals, foods and beverages. Examples of the preservative include paraben preservatives such as butyl paraoxybenzoate and quaternary ammonium preservatives such as benzalkonium chloride.

When the synthetic resin container of the present invention is an eye drop container, a thin film layer made of a desired metal such as Ti, Ag, TiO ₂ , SiO ₂ , silicon, or an oxide thereof is formed on the inner face of the eye drop container using, for example, a sputtering technique. Is preferably formed. The thickness of the thin film layer on the inner surface of the ophthalmic container is not particularly limited, and may be determined in consideration of the characteristics of the organic compound contained in the ophthalmic solution, the type of the thin film, and the like.

If a thin film layer of metal, silicon or their oxide is formed on the surface of a synthetic resin molding or the inner surface of a synthetic resin container by a thin film forming technique using plasma, the surface of the synthetic resin molding or the inner surface of the synthetic resin container It is possible to effectively suppress the adsorption of the organic compound. As a specific example, it will be described in detail in the section of the adsorption suppression test described later, but when a thin film layer of Ti, Ag, TiO ₂ , SiO ₂ was formed on a polyethylene resin, all of them markedly decreased the content of organic compounds Suppressed.

The following shows the results of an adsorption suppression test using a resin piece obtained by plasma-depositing Ti, TiO ₂ , Ag, and SiO ₂ , which is for better understanding of the present invention. It is not limited.

[Adsorption suppression test]
Test Example 1 [Vitamin E adsorption suppression test using a resin piece on which Ti was plasma-deposited]
(experimental method)
Using a sputtering apparatus (L-332S-FH manufactured by Anelva), in the presence of Ar gas (discharge pressure: 0.5 Pa), DC power (discharge current: 0.4 A) is applied to the target, and the target material is used. Some Ti was evaporated and vapor-deposited on both sides of a plate-like polyethylene resin piece (thickness 1 mm, 30 mm × 15 mm, hereinafter referred to as “PE piece”) attached to a holder on the target. By controlling the plasma irradiation time (5-250 seconds) during plasma irradiation, each Ti sputtering thin film-treated PE piece having an average film thickness of 2 nm, 20 nm, and 100 nm was obtained.

  Next, prepare a plurality of glass bottles containing 14.4 mL of a test solution containing 0.0007% vitamin E (w / v), and obtain a Ti sputtering thin film-treated PE piece and an untreated PE piece having a film thickness of 2 nm, 20 nm, and 100 nm. Two pieces were immersed in the test solution in separate glass bottles, and the test solution was shaken at 40 ° C. Vitamin E content in each test solution was measured using a high performance liquid chromatograph (Waters 2695 or 2487 manufactured by Waters, the same unless otherwise specified) after 0 (before PE piece immersion), 1, 2 and 7 days later. .

 The residual rate of vitamin E was calculated by the following formula.

Residual rate = Vitamin E content at the time of measurement / Vitamin E content before immersion x 100
(result)
FIG. 1 shows the change in the residual rate of vitamin E (average value of three times) for each film thickness.

(Discussion)
As is clear from FIG. 1, the Ti sputtering thin film-treated PE piece exhibits an excellent vitamin E adsorption suppressing action.

Test example 2 [Dibucaine hydrochloride adsorption inhibition test using a plasma-deposited piece of Ti]
(experimental method)
0. A plurality of glass bottles containing 5 mL of a 005% dibucaine hydrochloride (w / v) -containing test solution were prepared, and two 20 nm-thick Ti sputtering thin film treated PE pieces and untreated PE pieces obtained in Test Example 1 were separately prepared. It was immersed in a test solution in a glass bottle, and the test solution was shaken at 40 ° C. The content of dibucaine hydrochloride was measured using a high performance liquid chromatograph after 0 (before PE piece immersion) and after 2 and 7 days.

  The residual ratio of dibucaine hydrochloride was calculated by the following formula.

Residual rate = dibucaine hydrochloride content at the time of measurement / dibucaine hydrochloride content before immersion × 100
(result)
Table 1 shows the change in the residual ratio of dibucaine hydrochloride (average value of 3 times each).

(Discussion)
As is clear from Table 1, the Ti sputtering thin film-treated PE piece exhibits an excellent dibucaine hydrochloride adsorption suppressing action.

Test Example 3 [Vitamin E adsorption suppression test using a resin piece on which TiO ₂ is plasma-deposited]
(experimental method)
Using a sputtering apparatus, high-frequency power (discharge power: 40 W) is applied to the target while introducing O ₂ (flow rate: 5 sccm) in the presence of Ar gas (discharge pressure: 0.5 Pa). Some Ti was evaporated and deposited on both sides of the PE piece attached to the holder on the target. During plasma irradiation, plasma irradiation time (1200-3000 seconds) was controlled to obtain TiO ₂ sputtering thin film-treated PE pieces having a film thickness of 20 nm and 50 nm.

Next, a plurality of glass bottles containing 14.4 mL of a test solution containing 0.0007% vitamin E (w / v) were prepared, and 2 pieces of 20 nm and 50 nm TiO ₂ sputtering thin film treated PE pieces and untreated PE pieces were prepared. Each piece was immersed in a test solution in a separate glass bottle, and the test solution was shaken at 40 ° C. Vitamin E content was measured using a high performance liquid chromatograph at 0 (before the PE piece immersion) and 2 days later.

 The residual rate of vitamin E was calculated by the calculation formula shown in Test Example 1.

(result)
Table 2 shows the residual rate of vitamin E at each film thickness (average value of 3 times each).

(Discussion)
As is clear from Table 2, the TiO ₂ sputtering thin film-treated PE piece exhibits an excellent vitamin E adsorption inhibiting action.

Test Example 4 [Vitamin E adsorption suppression test using a resin piece on which Ag was plasma-deposited]
(experimental method)
A sputtering apparatus is used to evaporate Ag as a target material by applying DC power (discharge current: 0.4 A) to the target in the presence of Ar gas (discharge pressure: 0.5 Pa). Vapor deposition was performed on both sides of the PE piece attached. During the plasma irradiation, the plasma irradiation time (3 to 100 seconds) was controlled to obtain 4 nm and 20 nm Ag sputtering thin film treated PE pieces.

  Next, a plurality of glass bottles containing 14.04 mL of a test solution containing 0.0007% vitamin E (w / v) were prepared, and two pieces of 4 nm and 20 nm Ag sputtering thin film treated PE pieces and untreated PE pieces were prepared. Each was immersed in a test solution in separate glass bottles, and the test solution was shaken at 40 ° C. The residual rate of vitamin E was measured using a high performance liquid chromatograph at 0 (before the PE piece immersion) and 2 days later.

 The residual rate of vitamin E was calculated by the calculation formula shown in Test Example 1.

(result)
Table 3 shows the residual rate of vitamin E at each film thickness (average value of 3 times each).

(Discussion)
As apparent from Table 3, the Ag sputtering thin film-treated PE piece exhibits an excellent vitamin E adsorption suppressing effect.

Test Example 5 [Test for inhibiting adsorption of butyl paraoxybenzoate using a resin piece obtained by plasma-depositing SiO ₂ ]
(experimental method)
Using a sputtering apparatus, Si as the target material is evaporated by applying high frequency power (discharge power: 40 W) to the target while introducing O ₂ in the presence of Ar gas (discharge pressure: 0.5 Pa), It vapor-deposited on both sides of PE piece (distance of a target and PE piece: 100mm) attached to the holder on a target. At the time of plasma irradiation, the holder was rotated (30 rpm), the plasma irradiation time was 4800 seconds, and an SiO ₂ sputtering thin film treated PE piece having an average film thickness of 100 nm was obtained.

Prepare a plurality of glass bottles containing 120 mL of 0.002% butyl paraoxybenzoate (w / v) -containing test solution, and separate glass bottles each containing 100 nm thick SiO ₂ sputtering thin film treated PE pieces and three untreated PE pieces. The sample was immersed in the test solution and stored under conditions of 40 ° C. and 75% RH. The content of butyl paraoxybenzoate was measured using a high performance liquid chromatograph after 0 (before PE piece immersion) and after 84 days.

 The residual rate of butyl paraoxybenzoate was calculated by the following formula.

Residual rate = Butyl paraoxybenzoate content at the time of measurement / Butyl paraoxybenzoate content before immersion × 100
(result)
Table 4 shows the residual ratio of butyl paraoxybenzoate (average value of three times each).

(Discussion)
As is apparent from Table 4, the SiO ₂ sputtering thin film-treated PE piece exhibits an excellent effect of suppressing adsorption of butyl paraoxybenzoate.

FIG. 1 is a graph showing the result of adsorption suppression test using a Ti-sputtered thin film-treated PE piece (change in vitamin E residual rate).

Claims (14)

A method for suppressing the adsorption of an organic compound to a synthetic resin molding, comprising forming a thin film layer of metal, silicon or an oxide thereof on the surface of the synthetic resin molding by a thin film forming technique using plasma. A method for suppressing the adsorption of an organic compound to the inner surface of a container, comprising forming a thin film layer of metal, silicon, or an oxide thereof on the inner surface of a synthetic resin container by a thin film forming technique using plasma. The method according to claim 1 or 2, wherein the synthetic resin is a polyolefin resin, a polystyrene resin or a polyester resin. The method according to claim 3, wherein the polyolefin resin is a polyethylene resin, a polypropylene resin or a polyethylene terephthalate resin. The method according to claim 1 or 2, wherein the thin film forming technique using plasma is a sputtering technique. Metal, silicon, or an oxide thereof, Ti, Ag, method of claim 1 or 2, wherein the TiO ₂ or SiO _2. The method according to claim 1 or 2, wherein the thickness of the thin film layer is 1 µm or less. The method according to claim 1 or 2, wherein the organic compound is an additive acceptable for a drug or a pharmaceutical product, food or beverage. The method according to claim 2, wherein the synthetic resin container is an aqueous liquid container. The method according to claim 9, wherein the aqueous liquid container is an eye drop container or a plastic bottle. A synthetic resin molded article in which adsorption of an organic compound is suppressed by the method according to claim 1. A synthetic resin container in which adsorption of an organic compound is suppressed by the method according to claim 2. Synthesis excellent in suppressing adsorption of organic compounds to synthetic resin moldings, characterized by forming a thin film layer of metal, silicon or their oxides on the surface of synthetic resin moldings using plasma-based thin film formation technology Resin molding. A synthetic resin container excellent in suppressing adsorption of an organic compound to the inner surface of a container, wherein a thin film layer of metal, silicon or an oxide thereof is formed on the inner surface of the container by a thin film forming technique using plasma.

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