Antibacterial layered material

Abstract

The present invention relates to an antibacterial layered material comprising a layer containing a particulate biocidal active and a layer disposed thereon as a transport control layer, the transport control layer being capable of being or has been deposited by an afterglow PE-CVD method. The invention further relates to substrates coated with this type of antibacterial layered material, the use of an afterglow PE-CVD deposited plasma polymer layer as a transport control layer for the particulate biocidal active, a method for producing the antibacterial layered material, and a method for producing a substrate with the antibacterial layered material.

Description

[Technical Field]

[0001] The present invention relates to an antibacterial layer material comprising a layer containing a particulate biocidal active ingredient and an overlying layer as a transport control layer, wherein the transport control layer can be or has been deposited by an afterglow PE-CVD method. The present invention further relates to substrates coated with such antibacterial layer materials, the use of afterglow PE-CVD deposited plasma polymer layers as transport control layers for the particulate biocidal active ingredient, and methods for producing the antibacterial layer material and methods for producing substrates with the antibacterial layer material. [Background technology]

[0002] In the prior art, there is a constant need to optimize antibacterial coatings for various needs. The definitive standards for antibacterial testing are according to standards ASTM E2149, JIS Z 2801 / ISO22196 and JIS L 1902 / ISO20743. To be able to successfully pass these tests, the biocide release must be controlled via the properties of the transport control layer. DE 10353756 A1 discloses a layer material comprising a particulate silver layer. However, the release properties here are not sufficiently developed for applications requiring improved release, especially at an early stage. Summary of the Invention

[0003] Against this background, the object of the present invention was to identify antimicrobial layer materials that are improved in terms of their release properties, especially at the initial point of their use. This object is achieved according to the present invention by an antibacterial layer material comprising a layer containing a particulate biocidal active ingredient and a plasma polymer layer thereon as a transport control layer, the transport control layer being depositable or having been deposited by an afterglow PE-CVD method. DETAILED DESCRIPTION OF THE INVENTION

[0004] Surprisingly, it has been found that transport control layers deposited by the afterglow method have particularly favorable emission properties. According to the present invention, in the afterglow method, the substrate is placed in a parallel plate reactor for PE-CVD (plasma enhanced chemical vapor deposition) so that the distance between the substrate and the plasma electrode is at least 30 times the distance of the dark zone. The dark zone is a cathode trap where the plasma potential drops to the cathode potential. An active ingredient is biocidal in the context of the present application if it has antibacterial action within the meaning of JIS Z 2801 / ISO22196, i.e. if it reduces bacteria by at least a factor of 100 under the conditions described therein, especially for antibacterial surfaces, although biocides in the context of the present invention preferably reduce bacteria by at least a factor of 1000 under the same conditions. A biocidal active ingredient is in particulate form when it is present in separate, mutually distinguishable particles or particle agglomerates rather than forming a continuous layer. Preferred are layer materials according to the invention, in which the transport control layer has a layer thickness of 320 nm or less, preferably 160 nm or less, more preferably 80 nm or less and / or 5 nm or more, preferably 20 nm or more. wherein each lower limit or preferred upper limit can be combined with each individual one of the upper limits, wherein it is even more preferred that the antibacterial layer material comprises a transport control layer having a layer thickness of 20 to 35 nm. In the preferred layer thickness ranges, and more particularly in the particularly preferred layer thickness ranges, the transport-controlling layers for use according to the invention ensure particularly good release profiles. Transport control layers for use according to the present invention having a base material selected from the group consisting of plasma polymer layers comprising the elements Si, O, C, Ti, Al, N and / or H are preferred, with plasma polymer layers consisting solely of these elements being more preferred, although it is recognized that not all of the listed elements need be present.

[0005] The transport control layer preferably has a silicon content of 20 to 60 atomic % and / or a carbon content of 10 to 30 atomic % and / or an oxygen content of 30 to 50 atomic % in each case relative to the total number of all atoms measurable by XPS, i.e., excluding in particular hydrogen. In this regard, it is particularly preferred that the transport control layer consist of carbon, oxygen, silicon and hydrogen, with the proportions of the elements carbon, silicon and oxygen most preferably within the ranges stated above. Preferred are antimicrobial layer materials in which the particulate biocidal material has a limit size of 100 nm or less, preferably 50 nm or less, more preferably 20 nm or less, where limit size and teeth, The relevant 95% of the particles The grain size is smaller than that. It is child-sized. In this case, for the avoidance of doubt, in the context of this document, particle size is determined as described in Measurement Example 1 (see below). Surprisingly, it has been found that the particulate biocidal material has a preferred limit size of 80 nm or less, preferably 25 nm or less, more preferably 15 nm or less, where limit size and teeth, The relevant 95% of the particles The grain size is smaller than that. It is child-sized.

[0006] Preferred are antimicrobial layer materials of the present invention in which the ratio of the layer thickness of the transport control layer to the critical size of the particles is greater than or equal to 1.4, preferably greater than or equal to 10. Surprisingly, it has been found that the ratio of the thickness of the transport control layer to the critical size of the biocide particles can make a significant positive contribution to the desired release profile. Preferably, according to the present invention, the biocidal active ingredient is silver, copper or zinc, or an organic biocide, with silver and copper being particularly preferred, and silver being most preferred.

[0007] The metal biocides preferred herein can be applied preferably by PVD methods, in particular by sputtering or vapor deposition. The prior art discloses a number of methods for producing granular organic biocides. For example, it is possible to deposit quaternary ammonium compounds in granular form from the gas phase, although wet chemical methods are also available. A preferred method for depositing granules is, in particular, inkjet printing of the organic biocide. Preferred organic biocides for use according to the present invention are quaternary ammonium compounds (e.g., methacrylamidopropyltrimethylammonium chloride) and quaternary phosphonium compounds. According to the present invention, the concentration of the biocidal active ingredient is 0.3 to 10 μg / cm 2 , preferably 0.5 to 5 μg / cm 2 , and more preferably 1 to 4 μg / cm 2 Preferred are antimicrobial layer materials which are: These concentrations are especially applicable to metal biocides, and very particularly silver as the biocide. For the avoidance of doubt, the area concentration of the biocidal active ingredient is determined in a top view, i.e., vertically from above. If there is more than one separate layer containing a granular biocidal active ingredient, the area concentration is determined separately for each of these layers. In other words, in the case of a multi-layer system having more than one biocidal layer, the concentrations of the biocidal active ingredient across the multiple layers are not added together. The preferred layer concentrations support the desired release profile.

[0008] According to the invention, antibacterial layer materials are preferred, in which the plasma polymer layer consists of the elements Ti, O and C or the elements Si, O, N and C, preferably the elements Si, O and C, in each case to the extent of at least 95 atomic %, relative to the number of atoms determined by XPS. According to the present invention, the transport control layer has a thickness of 1000 cm 3 Antimicrobial layer materials of the present invention having an O2 permeability of 1 / (day x bar) or more are preferred. For the avoidance of doubt, the determination of O2 permeability is carried out as described in Example 2. The oxygen permeability of the preferred antimicrobial layer material demonstrates a particularly good release profile. Note that the oxygen permeability characteristic in itself is not sufficient evidence that the transport-controlling layer has the desired release profile. In fact, there must be additional characteristics, such as layer configurations that can be produced, particularly in this case by the afterglow method. Further preferred according to the present invention is an antimicrobial layer material, wherein a 50% H2O2 solution at 25°C bleaches said layer within 12 hours, preferably within 8 hours, more preferably within 6 hours.

[0009] It is clear that the bleaching of the layer material depends on the thickness of the layer, especially the outer layer. Experiments have shown that with increasing thickness of the transport control layer, the bleaching time increases almost exponentially, rather than linearly. At a thickness of 40 nm (for a given composition of the transport control layer), complete bleaching within 25 minutes or less, preferably 20 minutes or less, more preferably 15 minutes or less, even more preferably 10 minutes or less, and more preferably 5 minutes or less is characteristic of transport control layers for use according to the invention ("depositable or deposited by afterglow PE-CVD"). For completeness and to avoid any doubt, it should be mentioned that the substrate on which these bleaching tests were performed was glass. For the avoidance of doubt, decolorization can be determined under the conditions of measurement example 3, selecting variant 1. In the context of the present invention, a sample is considered to be decolorized if it meets the conditions of Measurement Example 3. As with metal biocides, it is also possible to monitor the removal of organic biocides from the layer by spectral means.

[0010] The bleaching of the preferably silver-containing layer material of the present invention with a suitable H2O2 solution is a good indication that the transport control layer is indeed to be used according to the present invention. The favorable bleaching results mentioned can only be achieved when a coating produced or producible by the afterglow method is present in combination with a biocide for use according to the present invention. This is because the transport control layer for use according to the present invention ensures that the bleaching material can fully contact the sample. According to the present invention, antimicrobial layer materials of the present invention are preferred, wherein after deposition and before activation, the transport control layer has a surface energy of 48 mN / m or less as measured by test ink from Acrotec GmbH to ISO 8296. The corresponding surface energy is preferably 40 mN / m or less. According to the present invention, the antimicrobial layer material of the present invention is preferred, wherein a (further) layer is provided on the side of the biocide layer remote from the transport control layer, preferably in a configuration as defined for the transport control layer in any of the preceding claims.

[0011] This additional layer would be provided on the side of the transport-controlling layer facing the substrate. It can be used, first, to promote adhesion, but second, it can also help, for example, to reduce or eliminate any adverse effects of the substrate on the biocide or biocide release. Such adverse effects could be, for example, the formation of undesirable redox couples. Additionally, a pre-coating can be used to adjust the surface energy of the underlying layer. It is up to those skilled in the art to configure this additional layer to achieve the desired effect. In many cases, and preferably, the embodiments as defined above for the transport control layer are suitable for this additional layer, especially in preferred embodiments. Here, the transport control layer does not necessarily have to have the same composition as the additional layer, although in some cases deposition conditions may make the use of the same layer preferable.

[0012] In many cases, it may be preferable for the antimicrobial layer material of the present invention to comprise more than one biocidal active ingredient layer. The composition of this additional active ingredient layer may be the same as that used in accordance with the present invention, but may differ depending on its intended use. However, it is clear that it is preferable to use multiple biocidal layers laminated together, each having a particulate biocidal active ingredient as defined above, to be used in accordance with the present invention, in which case these biocidal layers are preferably separated from each other by a transport control layer, more preferably similar to one of the forms to be used in accordance with the present invention identified above as preferred. With the aid of "multi-layer" biocide layers, further release profiles can be established in an excellent manner. This is especially true when, on the one hand, a rapid release is desired, but also when, on the other hand, release over a maximum period of time is required.

[0013] Also part of the present invention is a substrate having the antimicrobial layer material of the present invention, wherein the substrate of the present invention may be partially or completely coated with the antimicrobial layer material of the present invention, preferably coated with the antimicrobial layer material of the present invention at least in areas that potentially come into contact with microorganisms when used as intended. According to the present invention, the inventive substrate having the inventive antimicrobial layer material is preferably selected from the group consisting of pharmaceutical products, hygiene products and packaging materials for human and / or veterinary applications.

[0014] Pharmaceutical products are, inter alia, catheters, wound dressings, wound dressings, contact lenses, implants such as medical nails, screws, bone fixation nails, dental implants, hip implants, knee implants, implants for spinal fixation, vascular implants and temporary implants, and medical devices, which also expressly include implants and devices for use in the veterinary field. Hygiene products are, inter alia, napkins and diapers. The packaging material is useful, inter alia, for medical or hygiene products. The substrates of the present invention can also be components for food manufacturing or processing. Coatings for other products where special hygiene is required are also useful. In the substrates of the present invention, especially the preferred substrates, the release profile possible with the antimicrobial layer materials of the present invention is found to be particularly conducive. Also part of the present invention is the use of a plasma polymer layer for use according to the invention as defined above as a transport control layer for a particulate biocidal active ingredient.

[0015] Also included in the method of the present invention is a method for producing the antimicrobial layer material of the present invention, comprising: a) depositing a granular biocidal layer as further defined above, used in accordance with the present invention; b) after step a), depositing a plasma polymer transport control layer by afterglow CVD, the transport control layer preferably configured as defined above; The method includes: Also part of the present invention is a method of making a substrate of the present invention having an antimicrobial layer material, comprising: a) providing a substrate; b) depositing an antimicrobial layer material on a substrate in accordance with the method of the present invention as described above for producing the antimicrobial layer material; The method includes: In particular, the method of the present invention with the preferred configuration, and more particularly with the preferred materials, can be used to produce antimicrobial layer materials or antimicrobial coated substrates with excellent product-specific release profiles. These substrates of the present invention (with the antimicrobial layer materials of the present invention) can meet the above-mentioned specifications without difficulty. [Example]

[0016] Measurement example 1 Particle size determination FIB sections (focused ion beam preparation) of the sample to be analyzed were made, followed by TEM imaging (transmission electron microscopy), with an image detail of 100 nm x 100 nm (image size approximately 500 x 500 nm). Standard method: The particles, especially the silver particles, can be seen in the FIB-TEM image as a layer coated with a transport-controlling layer. By using an appropriate magnification (120,000 to 150,000 times), only particles that are completely covered with the transport control layer and reach the silver layer (PVD layer) are evaluated. Particles visibly protruding from the transport control layer are not evaluated. In the image detail, the appropriate particle is marked and measured by the largest particle diameter (longitudinal axis). The particles are sorted by size. Where appropriate, the particle size of the largest particle marked in the image detail is fixed as the reference parameter. Special case: the biocide particle is the only particle visibly resolved in the FIB-TEM image.

[0017] Individual particles are now measured in the figure. An image detail of 200x200 nm is fixed: the resolution should be chosen so that the lattice planes of the silver particles are shown as particle streaks / haze. In this section, the largest particles are identified by appearance, and among these, the particle with the largest particle diameter appearance (longitudinal axis) is identified. Particles with significant shrinkage (narrowing of more than 30% in the transverse axis) are considered as separate particles. This particle diameter is fixed and taken as the particle size.

[0018] Measurement example 2 Oxygen permeability measurement The oxygen transmission rate was measured using an OX-TRAN 2 / 20 instrument manufactured by Mocon, USA. The transport control layer was deposited on a polypropylene film with a thickness of 100 μm and a size of 10 cm × 10 cm. Prior to the measurement, the film was cut into 5 cm pieces so that the measurement surface was reduced by a factor of 10. 2 The coating was stacked on an aluminum foil screen with openings of 10. Therefore, the transmittance value measured by the instrument must be multiplied by 10. To determine the transmittance value of the coating, the following formula is used: Qs=Qg * Qf / (Qf-Qg) where Qg = transmittance value of the coated film, Qf = transmittance value of the uncoated film and Qs = transmittance value of the layer.

[0019] The oxygen permeability value Qf of the uncoated film is 2341 cm at 0% humidity. 3 / (day * bar). The exact operating procedure can be found in Chapter 8, "Testing Flat Film Samples," of the operating manual for the instrument manufactured by Mocon, Minneapolis, USA. For coated films, the measured value is Qg 1035 cm 3 / (day * bar), the permeability value of the coating on the polypropylene film is Qs 1855 cm 3 / (day * bar) is calculated. Measurement example 3 bleaching The bleaching is effective at room temperature of 25°C. The biocide for this test is preferably granular silver. The coating is tested with 50% hydrogen peroxide. The sample is preferably submerged by at least 1 cm 3 1cm layer 2 Cover with 50% H2O2 per 100 ml. This ensures that in each case an excess of peroxide is provided. Variant 1 (preferred): For comparison purposes, the same coating without the deposited biocide, especially silver, is used: this describes the bleaching layer under otherwise identical deposition conditions. Variation 2 (Simplified): An uncoated sample is used for comparison purposes. Variation 3: The same sample prepared via treatment with 50% H2O2 for at least 12 hours is used for comparison purposes. Bleaching: Samples are bleached in hydrogen peroxide and the bleaching of the samples is monitored by spectral means in the wavelength range of 320 nm to 780 nm (UV-VIS reflectance spectroscopy for non-transparent samples; UV-VIS spectroscopy for transparent samples).

[0020] A sample is considered to be decolorized if: - its spectrum (absorbance) is changed by peroxide treatment, and - if the spectrum of the sample to be tested is approximated to the reference spectrum by treatment with peroxide to an extent of at least 90%, this is the optical absorption constant k of the decolorized sample in the wavelength range of 300-500 nm The difference between the reference and the It is considered to have been achieved in this case. The time required for decolorization is recorded, with 12 hours being considered as the upper limit of the time recorded. Comparison between non-bleached and bleached samples by FIB-TEM imaging (see particle size) shows that "bleaching" correlates with the removal of biocide particles. Upon completion of bleaching, up to 10% of the particles originally present may be detectable as incorporated within the coating in the FIB-TEM image above.

[0021] Coating example Plasma system used The PA9 plasma system has a volume of 346 l and operates with a high-frequency plasma discharge (13.56 MHz). The plasma electrode (400 mm x 200 x 1 mm) is at a distance of 6.5 cm from the back wall. The substrate is placed at the same height and a given distance (Table 2) from the plasma electrode. The working gas is introduced into the reactor from the top (height = 76 cm, width = 68 cm, depth = 67 cm). Pump flanges are located at the bottom and middle of the reactor. The pump unit is 1200 m 3 / hr Roots pump and 80m 3 / h backing pump. The pump output of the reactor is approximately 1000 m at an operating pressure of 0.02 mbar. 3 / o'clock.

[0022] Experiment explanation The substrates (glass, Al-metallized PET film, and silicon wafer) are fixed at a given distance on an aluminum block. The Al block itself is at floating potential. The layer thickness or velocity is determined on the silicon wafer by reflectometry, and the layer transmittance is determined in a H2O2 solution (50%, RT). The glass substrate or the metallized PET film (80 nm Al on 50 μm PET film) is fixed on a SiO x C y H z The substrate is pre-coated with a layer (deposited as described in "Pre-coating" in Table 1) and sputtered with silver.

[0023] Metallic silver particles are deposited (sputtered) in the same reactor by HF magnetron sputtering. The magnetron has a diameter of 250 mm. The target material used is metallic silver (purity: 99.99%). * 10 -3 Once a base pressure of 100 mbar is obtained, argon is introduced into the chamber as working gas at a flow rate of 100 sscm. The sputtering power is 450 W. A target-substrate distance of 50 cm is selected. After a process time of 180 seconds, a diameter of less than 100 nm and 2 μg / cm 2 Silver particles having a concentration of The transport control layer as described in Table 1 was deposited on a granular silver layer (approximately 2 μg / cm) without activation. 2 ) and deposits on it. [Table 1] The size of the silver particles was determined by transmission electron microscopy (TEM). The diameter of the silver particles is approximately 15 nm. The color of the coating is reddish-yellow on the glass substrate and reddish-gold on the metallized PET film. Variation of the spacing was performed to determine the effect of plasma electrode-substrate spacing on transmittance. It is clearly evident from Table 2 that longer distances result in a more porous (afterglow) layer, as bleaching time increases significantly as spacing increases.

[0024] [Table 2] The comparative layer system corresponds to Example 1 of WO2005 / 048708A2, with the additionally deposited sublayer applied in the same way as the transport control layer of Example 1 to the substrate. In summary, it is found that the bleaching times of the layer system of the present invention are much shorter compared to layers deposited by the prior art and by the afterglow method, which indicates the favorable release profile made possible by the layers to be used according to the present invention.

Claims

1. An antibacterial layer material comprising a layer containing a particulate biocidal active ingredient and a plasma polymer layer thereon as a transport control layer, the plasma polymer layer being deposited by an afterglow PE-CVD method in which a substrate is arranged so that the distance between the substrate and the plasma electrode is at least 30 times the dark zone, the transport control layer utilizing silver particles as the particulate biocidal active ingredient, and the transport control layer having a thickness of 40 nm thereon, is resistant to 50% H2O at 25°C. 2 O 2 The antibacterial layer material is characterized in that the time required for complete decolorization of the antibacterial layer material by the solution is 25 minutes or less.

2. The antibacterial layer material according to claim 1 , wherein the transport control layer has a layer thickness of 320 nm or less.

3. 3. An antimicrobial layer material according to claim 1 or 2, wherein the particulate biocidal active ingredient has a limit size of 80 nm or less, the limit size being the particle size below which 95% of the particles fall.

4. 4. The antibacterial layer material according to claim 1, wherein the ratio of the thickness of the transport control layer to the critical size of the particles is 1.4 or more.

5. The antibacterial layer material according to any one of claims 1 to 4, wherein the particulate biocidal active ingredient is silver, copper or zinc, or the particulate biocidal active ingredient is an organic biocide.

6. The concentration of the granular biocidal active ingredient is 0.3 to 10 μg / cm 2 The antibacterial layer material according to any one of claims 1 to 5, wherein

7. The transport control layer is 1000 cm 3 / (days x bars) or more 2 The antibacterial layer material according to any one of claims 1 to 6, which has transmittance.

8. 8. The antibacterial layer material according to any one of claims 1 to 7, wherein an additional layer is provided on the side of the layer comprising the granular biocidal active ingredient remote from the transport control layer, in a configuration as defined for the transport control layer according to any one of claims 1 to 7.

9. A substrate comprising the antibacterial layer material according to any one of claims 1 to 8.

10. 10. The substrate according to claim 9, which is selected from the group consisting of pharmaceutical products for human and / or veterinary application, in particular implants and wound dressings, hygiene products and packaging materials.

11. Use of a plasma polymer layer as a transport control layer for a granular biocidal active ingredient in an antibacterial layer material comprising a layer containing a granular biocidal active ingredient and a plasma polymer layer thereon as a transport control layer, wherein the plasma polymer layer is deposited by an afterglow PE-CVD method in which a substrate is arranged so that the distance between the substrate and the plasma electrode is at least 30 times the distance of a dark zone, and the transport control layer uses silver particles as the granular biocidal active ingredient, and when the thickness of the transport control layer thereon is 40 nm, the transport control layer has a resistance to 50% H at 25°C. 2 O 2 The use of a plasma polymer layer, wherein the bleaching time required for the antibacterial layer material to be completely bleached by a solution is 25 minutes or less.

12. A method for producing the antibacterial layer material according to any one of claims 1 to 8, comprising the steps of: a) depositing a layer comprising a granular biocidal active ingredient as defined in any one of claims 1 to 8; b) after step a), depositing a plasma polymer layer as a transport control layer by afterglow PE-CVD, the transport control layer being configured as defined in any one of claims 2 to 7; A method comprising:

13. 11. A method for producing a substrate comprising the antimicrobial layer material of claim 9 or 10, comprising the steps of: a) providing a substrate; b) depositing an antimicrobial layer material on the substrate, in accordance with claim 12; A method comprising:

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