MXPA97000684A - Pipe assembly for san collection - Google Patents

Abstract

The present invention relates to a plastic container coated with a multilayer barrier coating. This multi-layer barrier coating is useful to provide an effective barrier against gas permeability in containers and to prolong the shelf life of containers, especially evacuated devices, made of plastic, for the collection of blood.

Description

PIPE SET FOR BLOOD COLLECTION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a multilayer barrier coating, to provide an effective barrier against the permeability of gas and water to containers, especially plastic tubes for blood collection. 2. Description of the Related Art With the increasing emphasis on the use of plastic products for medicine, there is a special need to improve the barrier properties of articles made of polymers. These medical products that would derive a considerable benefit from improving their barrier properties include, but are not limited to, collection tubes and particularly those used for blood collection. These blood collection tubes require certain standards. of performance are acceptable for use in medical applications. Such performance standards include the ability to maintain more than 90% of the original volume of extraction in a period of one year, be sterilizable by means of radiation and not interfere in testing and analysis. Therefore, there is a need to improve the barrier properties of articles made of polymers and, in particular, in evacuated plastic tubes for blood collection, in which certain performance standards must be met and the article is effective and can be used in medical applications. COMPENDIUM OF THE INVENTION The present invention relates to a container composed of plastic, with a multilayer barrier coating, disposed on the external or internal surface of the composite container, previously formed. Conveniently, the barrier materials comprise a mixture of an inorganic oxide and a metal oxide, applied to the surface of the composite vessel, previously formed. More preferably, the barrier materials comprise a first layer of a polymeric material, applied on the surface of the composite container, previously formed, and a second layer of a mixture of an inorganic oxide and a metal oxide, applied on the first layer. The polymeric material is preferably a highly interlaced acrylate polymer. The coating can be formed on a portion of the inner surface, on a portion of the outer surface, or both, of the container. The mixture of an inorganic oxide and a metal oxide may preferably be a metal oxide selected from Group IVA metals and a composition based on silicon oxide, such as SiOx, where x is from 1.0 to about 2.5.; or a composition based on aluminum oxide. More preferably, the mixture comprises SnOx and a composition based on silicon oxide. Preferably, the polymeric material is a mixture of monomers of monoacrylate (for example isobornyl acrylate) and diacrylate (for example an epoxy diacrylate or a urethane diacrylate), as described in US Pat. Nos. 4,490,774, 4,696,719, 4,647,818, 4,842,893, 4,954,371 and 5,032,461. whose descriptions are incorporated herein by reference. The polymeric material is cured by an electron beam or by a source of ultraviolet radiation. Conveniently, the polymeric material is formed of a substantially interlaced component, selected from the group consisting of polyacrylates and mixtures of polyacrylates, and monoacrylates having an average molecular weight between 150 and 1,000 and with a vapor pressure within the range of 1 × 10. ~ 6 up to 1 x 10-1 Torr, at standard temperatures and pressures. More preferably, the material is a diacrylate. Preferably, the thickness of the acrylate sizing coating is about 0.1 to 10 microns and more preferably about 0.1 to 5 microns. Conveniently, the mixture of the inorganic oxide and a metal oxide is preferably a mixture of a metal oxide, such as SnOx, GeOx or PbOx and a silicon or aluminum oxide. Such a mixture of oxides is conveniently deposited by means of the plasma polymerization of a mixture comprising tetramethyltin, oxygen and an organic volatile compound of silicon or aluminum, inside a capacitively coupled, magnetically enhanced, magnetic discharge discharge chamber. . Preferably, the thickness of the oxide mixture is from about 50A to 5000A, and more preferably from about 750 to 2000A. The composition of the oxide mixture provides a dense, vapor impermeable coating on the first layer. Preferably, the thickness of the silicon oxide-based coating is about 500 to 2,500 Angstroms (Á) and more preferably, when the first layer is of a polymer material and the second layer is of a mixture of oxides, the thickness of the second layer is greater than five times the thickness of the first layer. A coating above 5,000 A can split and, therefore, not be effective as a barrier. Optionally, another layer can be arranged on the mixed layer, which preferably comprises a polymer of vinylidene chloride-methyl methacrylate-methacrylate-acrylic acid (PVDC), thermoset epoxy coatings and parylene polymers or polyesters. Preferably, the thickness of the PVDC layer is about 2 to 15 microns and more preferably 3 to 5 microns. The process of applying the polymeric material to a container is preferably carried out in a vacuum chamber, in which a curable monomer component is dosed to a heated vaporizer system, where the material atomizes and condenses on the surface of the container. Following the deposition of the monomer on the surface of the container, it is cured by suitable means, such as electron beam curing. The deposition and cure steps can be repeated until the desired number of layers has been achieved. A method for depositing a mixture of inorganic oxides and metal oxide components is as follows: (a) pre-treat the vessel with a first oxygen plasma coating; (b) flowing, in a controlled manner, a gas stream, which includes an organic tin compound, an organic silicon compound and oxygen or an oxidizing gas compound, into a plasma; and (c) depositing the mixture of oxides on the container, while maintaining a pressure of less than about 500 mTorr, during the deposit. Although the pre-treatment step is optional, it is believed that this treatment step provides improved qualities of adhesion. Organic tin and silicon compounds can be combined with oxygen and, optionally, with helium, or another inert gas, such as argon or nitrogen. Preferably, the method for depositing a barrier coating on a substrate, such as a plastic collection tube, comprises the following steps: (a) select a curable component, which comprises: (i) polyfunctional acrylates or (ii) mixtures of onacrylates and polyfunctional acrylates; (b) rapidly vaporizing the component within the chamber; (c) condensing a first layer of a film of the vaporized component on the container; (d) cure the film; (e) applying a surface treatment of oxygen plasma on the film; (f) vaporizing an organic tin component and an organic silicon component with an oxidizing component and, optionally, an inert gas component, to form a gas stream outside the chamber; (g) establishing an irradiation plasma of radiation within the chamber, from one or more of the components of the gas stream; (h) flowing, in a controllable manner, the gas stream within the plasma, while confining therein at least a portion of the plasma; and (i) depositing a second layer, adjacent to the first layer. More preferably, the method of applying a barrier film coating to the inner wall surface of a container, comprises the following steps: (a) placing the open end of the container to a vacuum manifold system; (b) placing the outer surface of the container with an element for imparting energy into the container; (c) evacuate the container; (d) adding reactive gases, such as tin and the HDMSO inside the container; (e) imparting energy within the container; and (f) generating a plasma, within the container, and thus applying a coating of barrier film to the interior wall surface of the container.

Preferably, the source of monomers is an organic component of silicon, such as hexamethyldisyl-xano (HMDSO), tetraethoxysilane (TEOS) or tetramethylsilane (TMS). Preferably, the source of oxidation is air, oxygen or nitrous oxide. Preferably, the source of the diluting gas is an inert gas, such as helium, argon or a non-reactive gas, such as nitrogen. Preferably, the electrodes are metal electrodes coupled inductively or capacitively, in the form of coils, sharp bars or flat or curved plates. More preferably, the electrodes are energized with a power source, such as a low frequency alternating current (AC), electric radiofrequency (RF) or microwave frequency potentials, continuously or pulsed. More preferably, the method of applying a barrier coating to the interior wall surface of a container comprises the following steps: (a) placing the open end of the container to a vacuum collecting system; (b) placing the outer surface of the vessel with electrodes that are connected to an energy source; (c) maintaining a pressure of approximately 300 mTorr inside the container, evacuating this container with a vacuum pump; (d) flowing, in a controlled manner, an organic silicon component with an oxidizing component and an optional inert gas component, through the manifold system and into the container; (e) energizing the electrodes to thereby impart energy to the components within the container; (f) establishing an irradiation discharge plasma within the container; and (g) depositing a barrier film coating on the interior wall surface of the container.

Preferably, the steps of the method can be repeated, in which the electrodes in step (b) are repositioned on the external surface of the container. Alternatively, the steps of the method can be repeated, in which the electrodes in step (b) are deactivated and activated and / or the flow of the components in step (d) is deactivated and activated, in order to pulse the energy of the plasma or the flow of components, or both, in order to increase the barrier properties. Therefore, the steps of the alternative method can be the following: (h) de-energize the electrodes; e (i) energize the electrodes, in order to impart energy.

Another alternative method may be as follows: (h) stopping the flow of the components in step (d); e (i) then flowing again, in a controlled manner, the components as in step (d).

An alternative method may be as follows: (h) stopping the flow of the components in step (d); (i) de-energizing the electrodes in step (e); and (j) then repeating steps (d) - (g).

Optionally, the steps of the method can be repeated to ensure that the coating of the barrier film is applied uniformly throughout the interior of the container or to apply a second coating of barrier film. Optionally, layers of sizing or flattening can be interposed between the plastic substrate and the first layer, the oxygen plasma treatment of the first layer, before the deposit of the second layer and the use of other layers that increase the barrier on the Second layer. The plastic tubes coated with the multi-layer barrier coating and an overcoating layer, are able to substantially maintain better vacuum retention, extraction volume and retention of the thermomechanical integrity, compared to the previous tubes comprised of the compositions of the polymers and their mixtures, without a coating of the barrier materials, or of tubes comprising only an oxide coating. In addition, the resistance of the tube to impact is much better than that of the glass. More remarkably, it is the clarity of the multilayer coating and its durability, to withstand substantially better impact and abrasion resistance. Other attributes of the oxide blend coatings are that they are stable compared to conventional sterilization methods in medicine, such as gamma irradiation or ethylene oxide (ETO). More preferably, the container of the present invention is a device for collecting blood. This blood collection device can be either an evacuated blood collection tube or a non-evacuated blood collection tube. This blood collection tube is conveniently made of polyethylene terephthalate, polypropylene, polyethylene naphthalate or its copolymers.

An impression can be placed on the multilayer barrier coating applied to the container of interest. For example, a product identification, bar code, trade name, company logo, lot number, expiration date and other data and information may be included on the barrier coating. Also, the matte finish or a corona discharge surface can be developed over the barrier coating, in order to make the surface suitable for additional written information on the label. Similarly, a pressure-sensitive adhesive label can be placed on the barrier coating to accommodate several hospital over-labels, for example. Preferably, the multilayer barrier coating of the present invention provides a transparent or colorless appearance and may have printed matter applied to it. An advantage is that the method of the present invention provides a reduction in gas permeability of three-dimensional objects, which we have achieved with a conventional deposit method, typically used with thin films. It has been found in the present invention that the organic acrylate material provides a good platform for the growth of the material. dense metal oxide barrier of the IVA Group. It has been found that the highly interlaced layer of acrylate improves the adhesion between a plastic surface and a layer of a mixture of an inorganic oxide and a metal oxide and, in general, improves the thermomechanical stability of the coated system. In addition, the acrylate sizing coating has a role of a flattening layer (leveling), which covers the particles and imperfections on the surface of a polymer and reduces the density of defects in deposited inorganic coatings. The good binding properties of the acrylate are also due to the fact that the acrylate is polar and the polarity provides a means for good bond formation between the SiOx and the acrylate. In addition, it has been found that good bonding is obtained between plastic tubes made of polypropylene and acrylate. Thus, the present invention provides the resources to substantially improve the barrier properties of polypropylene tubes. The adhesion properties of both the acrylate coating and the oxide coating can be further improved substantially by previous methods of surface treatment, such as flame or oxygen plasma. Therefore, a significant reduction in the permeability of the article is due to the surface coverage of the metal oxide, substantially improved, which is obtained by the use of an acrylate sizing coating on the surface of the plastic article. A plastic blood collection tube, coated with a multilayer barrier coating, according to the present invention, will not interfere with the testing and analysis traditionally performed on blood in a tube. These tests include, but are not limited to, routine chemical analysis, biological inertness, hematology, blood chemistry, blood type, toxicology analysis or therapeutic drug monitoring and other clinical tests involving bodily fluids. Likewise, a plastic blood collection tube coated with the barrier coating, is capable of being treated in an automatic machinery, such as centrifuges, and may be exposed to certain levels of radiation in the sterilization process, substantially without change in the optical or mechanical and functional properties. DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a typical blood collection tube, with a stopper. Figure 2 is a longitudinal sectional view of the tube of Figure 1, taken along the line 2-2; Figure 3 is a longitudinal sectional view of a tube-shaped container, similar to the tube of Figure 1; , without a plug, comprising a multilayer barrier coating. Figure 4 is a longitudinal sectional view of a tube-shaped container, similar to the tube of Figure 1, with a stopper, comprising a multilayer barrier coating. Figure 5 is a longitudinal sectional view of a further embodiment of the invention illustrating the tube with a plug similar to Figure 1 and with the multilayer barrier coating covering both the tube and its cap. Figure 6 illustrates an amplified diagram, partially in section, of an instant evaporation apparatus. Figure 7 illustrates a plasma deposit system. Figure 8 is a general schematic diagram illustrating the apparatus for the generation of plasma. Figure 9 is a general schematic diagram illustrating the layers that are deposited on a substrate. Figure 10 is an ESCA spectrum of the mixture of an oxide compound of a Group IVA metal and a silicon oxide compound.

DETAILED DESCRIPTION The present invention can be incorporated into other specific forms and is not limited to any specific modality described in detail, which is merely exemplary. Various other modifications will become apparent and will be readily available to those skilled in the art, without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents. With reference to the drawings, in which similar reference characters refer to similar parts in all the various views. Figures 1 and 2 show a typical blood collection tube 10, having a side wall 11, extending from an open end 16 to a closed end 18, and a stopper 14, which includes a lower annular portion or skirt 15, which extends inside and is pressed against the inner surface 12 of the side wall, to hold the plug 14 in place. Figure 2 illustrates schematically that there are three mechanisms for a change in the vacuum in a blood collection tube: (A) gas permeation through the stopper; (B) the permeation of gas through the tube and (C) the leak at the interface of the tube and the plug. Therefore, when there is substantially no gas permeation and no leakage, there is good vacuum retention and good retention of the extraction volume. Figure 3 shows the preferred embodiment of the invention, a plastic tube coated with at least two layers of barrier materials. The preferred embodiment includes many components, which are substantially identical to the components of Figures 1 and 2. Therefore, FIG. similar components that perform similar functions will be numbered identically to those components of Figures 1 and 2, except that an "a" suffix will be used to identify those components in Figure 3. Referring now to Figure 3, the preferred embodiment of In the invention, the collection tube assembly 20 comprises a plastic tube 10a, having a side wall Ia, extending from an open end 16a to a closed end 18a. A barrier coating 25 extends over a substantial portion of the inner surface of the tube, with the exception of the open end 16a. The barrier coating 25 comprises a first layer 26 of a polymer material, such as an acrylate, a second layer 27 of an inorganic material, such as a composition based on silicon oxide, and a third layer 28 of an organic layer Overcoating, such as PVDC: Figure 4 illustrates an alternative embodiment of the invention, in which the collection tube assembly 40 comprises a plug 48 instead of the open end 41 that closes the tube 42. As can be seen , the side wall 43 extends from the open end 41 to the closed end 44 and the plug 48 includes an annular upper portion 50, which extends over the upper edge of the tube 42. The plug 48 includes a lower annular portion or skirt 49 , which extends into and presses against the inner surface 46 of the side wall 43, to hold the plug 48 in place. Likewise, the plug has a septum portion or partition 52, for receiving a cannula therethrough. Thus, the user, once he receives a container, as shown in Figure 4, with a sample contained therein, can insert a cannula through the septum 52 to receive part or all of the contents in the tube 42, so as to perform several tests on a sample. Covering a substantial portion of the length of the tube is a multilayer barrier coating 45. The multilayer barrier coating 45 covers substantially the majority of the tube, with the exception of its open aperture 41. The multilayer barrier coating 45 comprises a first layer 54 of a polymer material, a second layer 56 of a mixture of metal oxides, such as SnOx, GeOx or PbOx, and a silicon oxide material and a third layer 58 of an organic barrier material, such as PVDC. Figure 4 differs from the embodiment of Figure 3, in that the tube can be evacuated with the simultaneous placement of the plug 48, after the application of the layers 54 and 56 on the tube. Alternatively, the multilayer barrier coating can be applied to the tube after it has been evacuated. Figure 5 shows one more mode of barrier coating and a tube. The alternative modality operates in a manner similar to the modality illustrated in Figure 4. Therefore, similar components that perform similar functions will be numbered identically to the components in the embodiment of Figure 4, except that the suffix will be used. "a" for identifying those components in Figure 5. Referring now to Figure 5, a further embodiment of the invention, wherein the multilayer coating 45a incorporates both the upper portion 50a of the cap 48a, as well as the entire the external surface of the tube 42a. The multilayer barrier coating 45a includes saw teeth 62 at the tube interface and plug. These teeth are coincident, so that it can be determined if the sealed container has been violated. Such an embodiment can be used, for example, to seal the container with the cap in place. Once the sample has been placed inside the tube, the sample can not be violated by removing the plug. Additionally, the teeth can be coincident, so that it can be determined if the sealed container has been violated. Such an arrangement may be appropriate, for example, in drug abuse testing, identification of specimens and quality control. In an alternative embodiment of the invention, the multilayer barrier coating 45 is applied repeatedly or in sequence to the inner and / or outer surface of the tube. Preferably, the coating is applied at least twice. Practitioners of the art will understand that such tubes may contain reagents in the form of additives or coatings on the inner wall of the tube. The multilayer barrier coating forms a substantially clear or translucent barrier. Therefore, the contents of a plastic tube with a multilayer barrier coating, comprising at least two layers of barrier materials, are substantially visible to the observer at the same time as it identifies the information, since it can be displayed over the multilayer barrier coating, after it has been applied to the plastic tube. The first layer of the multilayer barrier coating can be formed on the tube by an immersion coating, roller coating or spraying an acrylate monomer or the monomer mixture, followed by the UV light curing process. The material of the acrylate polymer can also be applied to the tube by a process of evaporation and curing, carried out as described in the patent of E. U. A., No. 5,032,461, the disclosure of which is incorporated herein by reference. The evaporation of the acrylate and the curing process involve first atomizing the acrylate monomer into droplets of about 50 microns and then evaporating them and separating them from a hot surface. This produces a molecular vapor of acrylate, which has the same chemistry as the starting monomer. Acrylates are available with almost any desired chemical form. They usually have one, two or three acrylate groups per molecule. Various mixtures of mono-di- and tri-acrylates are useful in the present invention. More preferably, they are monoacrylates and diacrylates. Acrylates form one of the most reactive classes of chemicals. They heal quickly when exposed to UV light or electron beam radiation to form an interlaced structure. This imparts properties of abrasion resistance and high temperature in the coating.

The monomer materials used are of relatively low molecular weight, between 150 and 1,000, and preferably in the range of 200 to 300, and have vapor pressures between approximately lxlO "'5 Torr and lxlO-1 Torr, at standard temperature and pressure. (ie, they are relatively low boiling materials.) A vapor pressure of approximately lxlO "2 is preferred. Polyfunctional acrylates are especially preferred. The monomers used have at least two double bonds (ie, a plurality of olefinic groups). The high vapor pressure monomers used in the present invention can be vaporized at low temperatures and thus not degraded (decomposed) by the heating processes. The absence of non-reactive degradation products means that the films formed of these low molecular weight, high vapor pressure monomers have low volatile component levels. As a result, substantially all deposited monomers are reactive and will cure to form an integral film when exposed to a radiation source. These properties make it possible to provide substantially continuous coatings, despite the fact that the film is very thin. Cured films exhibit excellent adhesion and are resistant to chemical attack by organic solvents and inorganic salts.

Due to their reactivity, physical properties and other properties of cured films, formed from these components, polyfunctional acrylates are particularly useful monomeric materials., The general formula for these polyfunctional acrylates is: Rl - (OC - C = CH2) n | R2 wherein: R1 is an aliphatic, alicyclic or mixed aliphatic / alicyclic radical; R2 is a hydrogen, methyl, ethyl, propyl, butyl or pentyl; and n is from 2 to 4. Such polyfunctional acrylates can also be used in combination with various monoacrylates, such as those having the formula: ? i I CH3 (CH2) r- C - (CH2) S - X3 I CH20C-C = CH2"IO R2 where: R2 is as defined above, X1 is H, epoxy, 1,6-hexanediol, tripropylene glycol or urethane, and r, s are from 1 to 18.

OR CH2OC - C = CH2; and I * 2 ? 3 is CN or COOR3, where R3 is an alkyl radical containing 1 to 4 carbon atoms. More often, X3 is CN or COOCH3. The diacrylates of the following formula are particularly preferred: "CH2 (CH2) rCX1 (CH2) sCH2OC-CH = CH2 I CH2OC-CH = CH2 • 1 O where: X1, r and s, have the above definitions.

Healing is achieved by opening the double bonds of the reactive molecules. This can be achieved by means of an energy source, such as an apparatus that emits infrared, electron or ultraviolet radiation. Figure 6 illustrates the process of applying an acrylate coating. An acrylate monomer 100 is directed through a dielectric evaporator 102 and then through an ultrasonic atomizer 104 and into a vacuum chamber 106. The monomer droplets are atomized ultrasonically and they vaporize, where they condense on a rotating tube or film that is loaded onto a drum 108. The condensed monomer liquid is subsequently cured by radiation by means of an electron beam gun 110. The second layer of the multi-layer barrier coating, an inorganic material, can be formed on the acrylate coating by radiofrequency discharge, direct or double deposit of ion beams, electronic deposit or plasma chemical vapor deposition, as described in U.S. Patent Nos. 4,698,256, 4,809,876, 4,992,298 and 5,055,318, the disclosures of which are incorporated herein by reference. For example, a method of depositing an oxide coating is provided by establishing a radiation discharge plasma in the previously evacuated chamber. The plasma is derived from one or more components of the gas stream and is preferably derived from the gas stream itself. The article is placed in the plasma, preferably adjacent to the confined plasma, and the gas stream flows controllably within the plasma. The thickness of the second layer is from about 50 to 5000 A and preferably from about 750 to 2,000 A. The barrier film is deposited on the substrate to a desired thickness. A thickness less than 5,000 A may not provide a sufficient barrier, and a thickness greater than about 5,000 A may form cracks, thus decreasing the effectiveness of the barrier. More preferably, the thickness of the oxide coating is from about 1,000 to 3,000 Á. Another method for depositing an oxide coating is by confining a plasma with magnets. Preferably, the magnetically improved method for depositing a film based on silicon oxide on a substrate is preferably conducted in a chamber previously evacuated from irradiation discharge from a gas stream. The gaseous stream preferably comprises at least two components: a component of volatized organic silicon, an oxidizing component, such as oxygen, nitrous oxide, carbon dioxide or air, and, optionally, an inert gas component. Examples of suitable organic silicon and tin compounds, useful for the gas stream in plasma deposition methods, are liquid or gaseous at room temperature and have a boiling point of about 0 to 200 ° C., include: tetramethyl tin, tetraethyl tin, tetraisopropyl tin, tetraallyl tin, dimethylsilane, trimethylsilane, diethylsilane, propyl silane, phenylsilane, hexamethyldisilane, 1,1,2,2-tetramethyldi-silane, bis- (trismethylsilane) methane, bis- ( dimethylsilyl) -methane, hexamethyldisiloxane, vinyltrimethoxysilane, vinyltriethoxysilane, ethylmethoxysilane, ethyltrimethoxysilane, divinyltetramethyldisiloxane, hexamethyldisilazane, divinylhexamethyltrisiloxane, trivinyl-pentamethyltrisiloxane, tetrae-toxysilane and tetramethoxysilane. Among the preferred organic silicones are 1,1,3,3-tetramethyldisiloxane, trimethylsilane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethoxysilane, vinyltrimethoxysilane and hexamethyldisilazane. These preferred organic silicon compounds have boiling points of about 71.55.5, 102, 123 and 127ac, respectively.

The optional inert gas of the gas stream is preferably helium, argon or nitrogen. The volatized organic components of tin and silicon are preferably mixed with the oxygen component and the inert gas component, before flowing into the chamber. The quantities of these gases, thus mixed, are controlled by the flow controllers, in order to control in an adjustable manner, the ratio of the flow rate of the components of the gas stream. Various optical methods known in the art can be used to determine the thickness of the deposited film while in the deposit chamber or the thickness of the film can be determined after the article is removed from the deposit chamber. The deposition method of the present invention is preferably practiced at a relatively high power and a fairly low pressure. A lower pressure of about 500 milliTorr (mTorr) must be maintained during the deposit, and preferably the chamber is at a pressure between 43 and 490 mTorr, approximately, during the deposition of the film. The low pressure of the system results in lower deposit rates, while the higher system pressure provides higher deposit rates. When the plastic article to be coated is sensitive to heat, the higher pressure of the system can be used to minimize the amount of heat to which the substrate is exposed during deposition, because high temperatures of the substrate are avoided for polymers with low glass transition temperature (Tg), such as polypropylene and PET (Tg of -10ac and 60ßc, respectively) The substrate is electrically isolated from the deposit system, (except for electrical contact with the plasma) and is at a temperature of less than about 10 ° C during the deposit, that is, the substrate is not deliberately heated.With reference to Figure 7, the system for depositing a barrier coating including a second layer, comprises an enclosed reaction chamber 170, within which a plasma is formed and into which a substrate or tube 171 is placed, to deposit a thin film of material on a support 172 d Samples The substrate can be of any material compatible with vacuum, such as plastic. One or more gases are supplied to the reaction chamber by the gas supply system 173. An electric field is created by a power supply 174. The reaction chamber can be of an appropriate type to make any deposit of chemical vapor enhanced by plasma (PECVD) or a plasma polymerization process. Also, the reaction chamber can be modified so that one or more articles can be coated with an oxide layer simultaneously inside the chamber. The pressure in the chamber is controlled by a mechanical pump 188, connected to the chamber 170 by a valve 190. The tube to be coated is first faced within the chamber 170 in a sample holder 172. The chamber pressure is reduced to almost 5 mTorr by a mechanical pump 188. The operating pressure of the chamber is approximately 90 to 140 mTorr for the PECVD or the plasma polymerization process and is achieved by the flow of the chamber. the process gases, oxygen and trimethylsilane, inside the chamber through the monomer inlet 176. The thin film is deposited on the external surface of the tube and has a desired uniform thickness or the deposition process can be periodically interrupted to minimize the heating of the substrate and / or the electrodes and / or physically remove the particulate matter from the articles . The magnets 196 and 198 are placed behind the electrode 200, to create an appropriate combination of magnetic and electric fields in the region of the plasma around the tube. The system is suitable for low frequency operation. An example frequency is 40 kHz. Nevertheless, there may be some advantages of operating at a much higher frequency, such as in the radiofrequency range of several megahertz. Referring to Figure 8, the apparatus of the present invention includes a vacuum collector system 22. This vacuum manifold system includes at least five connections, 24, 26, 28, 30 and 32 and a coupling door 34 which is conveniently a rubber washer. The connections 24, 26, 28, 30 and 32 lead to the isolation gate valves 42, 44, 46, 48 and 50, respectively. The valves 42, 44, 46, 48 and 50 lead, respectively, to a monomer gas source 52, an oxidant gas source 54, a vacuum pump 56, a ventilation filter 58 and a diluent gas source 60, respectively. The apparatus further includes elements for creating energy, which include an external electrode system 62 and a power source 64. The power source preferably includes a tuner 66, an amplifier 68 and an oscillator 70. After the tube has been made by any suitable method of forming plastic tubes, such as injection molding, end cap extrusion, molding blow molding, blow molding injection etc. , the open end of the tube is first connected to the vacuum manifold system in the coupling door and all the valves are in the closed position. The valve 46 is then opened and the vacuum pump is started to reduce the pressure in the tube to the vacuum region from about 0.001 mTorr to 100 mTorr. The components of the reactive gas, necessary for the plasma to form inside the tube, are then introduced through the collector system into the tube. The valve 42 opens first, so that the monomer gas component flows into the manifold system at a pressure of about 125 mTorr, a flow rate of about 1.0 scsm, and an ambient temperature of about 23 ° C. The valve 44 is then opened so that the oxidizing gas component flows within the collector system at a pressure of approximately 175 mTorr, a flow rate of about 22 sccm and an approximate ambient temperature of about 23ac. The component of the monomer gas and the oxidizing gas component are preferably mixed with the inert gas component in the collecting system, before flowing into the tube. The quantities of these gases which are thus mixed are controlled by the flow controllers, in order to control in an adjustable manner the ratio of the flow rate of the components of the reactive gas stream. The mixture of reactive gas components is achieved inside the tube, before energizing the electrical system.

More preferably, the monomer gas component is preferably the HMDSO and the oxidizing gas component is preferably oxygen, in order to form and deposit a silicon oxide barrier coating (SiOx) on the surface of the inner wall of a tube. . The barrier coating is deposited on the inner surface of the tube to a desired thickness. The thickness of the coating is approximately 500 to 5000 Angstroms (Á). More preferably, the thickness of the oxide coating is from about 1000 to 3000 A. Optionally, a general control system, which includes a portion of computer control, is connected to each of the components of the system in such a manner as to receive status information from, and send command controls to, them. The appropriate pressure of the reactive gas mixture is between about 70 mTorr and about 2,000 mTorr, preferably between about 150 raTorr and 600 mTorr, and more preferably about 300 mTorr. Conveniently, an organic silicon, such as HMSO and tetramethyl tin are used as the components of the monomer gas, at a flow rate of about 0.1 to 50 sccm, at 25 ° C, and an approximate pressure of 80 to 190 mTorr, preferably 0.5 to 15 sccm and more preferably 1.0 sccm, roughly.

Conveniently, air is used as the component of the oxidizing gas, at a flow rate of about 0. 1 to 50 sccm (at 25ac) and a pressure of about 110 to 200 mTorr, preferably about 15 to 35 sccm and more preferably about 22 sccm. The barrier film blend, used in accordance with this disclosure, may contain conventional additives and ingredients that do not adversely affect the properties of the articles obtained therefrom. The optional third layer of the multilayer barrier coating can be formed on the second layer by a dip coating, roller coating or by spraying an aqueous emulsion of the polyvinylidene chloride, or its homo- or co-polymers, followed by the air drying. The third layer may preferably be copolymers of vinylidene chloride-acrylonitrile methyl methacrylate-methyl acrylate-acrylic acid, thermoset epoxy coatings, polymers or poly-esters of parilane.

Preferably, the third layer is a parylene polymer. Parylene is the generic name of the members of the polymer series developed by Union Carbide Corporation. The basic member of the series, called the parylene N, is the poly-p-exlylene, a linear crystalline material: Parylene C, a second member of the parylene series, is produced from the same monomer as parylene N and modified by the substitution of a chlorine atom for one of the aromatic hydrogens: Parylene D, a third member of the parylene series, is produced from the same monomer as parylene N and modified by a substitution of the chlorine atom by two of the aromatic hydrogens: More preferably, the layer is a polymer of vinylidene chloride-methyl methacrylate-methacrylate-acrylic acid (PVDC). This polymer is available as DARAN® 8600-C (trademark of R. Grace and Co.), sold by GRACE, Organic Chemicals Division, Lexington, Mass., USA The third layer of the barrier coating, can be a polymer of parylene applied to the second layer by a process similar to vacuum metallization, as described in US Patents Nos. 3,342,754 and 3,300,332, the disclosures of which are incorporated herein by reference. Alternatively, the optional additional material may be a polymer of vinylidene chloride-acrylonitrile-methyl methacrylate-methyl acrylate-acrylic acid, applied to the second layer by dip coating, roller coating or spraying an aqueous emulsion of the polymer, followed by air drying the coating, as described in the patents of E. U. A., Nos. 5,093,194 and 4,497,859, the disclosures of which are incorporated herein by reference. As shown in Figure 9, the acrylate coating A and the second mixed layer B may have defects or irregularities C. It is believed that a completely defects free coating of the substrate D can not be achieved with only the acrylate and the layer mixed Therefore, a third coating of PVDC, E, is applied on the layer to produce a barrier coating substantially free of defects on the surface of the substrate. A variety of substrates can be coated with a barrier coating by the process of the present invention. Such substrates include, but are not limited to packs, containers, bottles, jars, tubes and medical devices. A plastic tube for blood collection, coated with the multilayer barrier coating, will not interfere with tests and analyzes, which are traditionally performed on blood in a tube. Such tests include, but are not limited to, routine chemical analysis, inert biological status, hematology, blood chemistry, blood type, toxicology analysis or therapeutic drug monitoring, and other clinical tests involving body fluids. Also, the plastic blood collection tube, coated with the barrier coatings, is capable of being treated in an automatic machinery, such as centrifuges, and can be exposed to certain radiation levels in the sterilization process, substantially without change in the optical or mechanical and functional properties. A plastic blood collection tube, coated with the barrier coating, is able to maintain 90% of the original volume extracted, in a period of one year. The retention of the volume of extraction depends on the existence of a partial vacuum, or a reduced pressure, inside the tube. The extracted volume changes in direct proportion to the change in vacuum (reduced pressure). Therefore, the retention of the extraction volume depends on the good retention of the vacuum. A plastic tube coated with the composition, not ideal, of sequence of barrier coatings substantially prevents the permeation of gas through the material of the tube, in order to maintain and increase the retention of the vacuum and the retention of the volume extracted from the tube. Plastic tubes without the coating of the non-ideal composition of the sequence of barrier coatings of the present invention can maintain about 90% of the extracted volume for about 3 to 4 months. If the multilayer barrier coating is also coated or applied to the inner surface of the plastic tube for blood collection, this barrier coating can be hemo-repellent and / or have characteristics of a clot activator. It will be understood that no difference is made if the plastic composite container is evacuated or not evacuated, in accordance with this invention. The presence of the barrier coating on the external surface of the container has the effect of maintaining the general integrity of this container that retains the sample, so that it can be properly disposed without any contamination to the user. Remarkable is the clarity of the barrier coating and its resistance to abrasion and scratching. The barrero coating used in accordance with this description may contain conventional additives and ingredients, which do not adversely affect the properties of the articles made thereof. The following examples are not limited to any specific embodiment of the invention, and are exemplary only. Example 1 A polypropylene tube was connected to a vacuum manifold system and with external plate electrodes, parallel, surrounding the outside of the tube. A vacuum of approximately 60 mTorr was first pushed into the tube. Air was then introduced at about 200 mTorr into the tube through the collector system and the electrodes were energized at 30 watts from a 38MHz oscillator, for about 30 seconds, to provide a surface activation treatment. While the plasma is energized, a mixture of tetramethyl tin vapor monomer gas and hexamethyldisiloxane (1:20 v / v) was added into the tube through the manifold, until the total pressure of the gas mixture out of about 250 mTorr. The plasma reservoir was maintained for about 5 minutes, followed by 90 seconds of air treatment. After depositing the SnOx / SiOx on the inner wall surface of the tube, the tube was disconnected from the collector. Example 2 A PET tube was connected to a vacuum collector system and to external plate electrodes, parallel, that surround the outside of the tube. A vacuum of about 60 mTorr was first pushed into the tube. Air was then introduced into the tube at a pressure of about 150 mTorr. Then a mixture of tetramethyltin vapors and hexamethyldisiloxane (1:20 v / v) was introduced into the tube to a total pressure of the gas mixture within the tube of about 200 mTorr. The electrodes were energized at 38 MHz and 22 watts for about 5 minutes, so that a plasma was generated inside the tube.

After depositing the SnOx / SiOx on the inner wall of the tube, the tube was disconnected from the collector. Example 3 A Surface Science Model SSx-100 X-ray photoelectron (ESCA) spectrometer was used to determine the atomic% of the elements present in the oxide coatings. The film samples were placed inside the spectrometer and the elemental composition of approximately 100A was determined on the surface. The surface was then etched with argon ions as follows: an argon ion beam of 5000V and 9-10 mA was directed to the surface of the sample. After 5 seconds, the ESCA spectrum was taken and this procedure was repeated for a total of 5 times. The engraving time was then increased to 20 seconds, followed by the ESCA spectrum and this process was repeated for a total of ten times. Finally, the etching time was increased to 40 seconds and the ESCA spectrum was obtained until the acrylate volume or the polymer substrate was reached. The oxide layer was clearly indicated by the presence of silicon in the ESCA spectrum between the etching times of approximately 0 and 1.3 minutes. The results are given in Figure 10.

Claims (23)

1. CLAIMS 1. A sample assembly, which comprises: a plastic container, having an open end, a closed end, an internal surface and an external surface; and a multi-layered barrier coating, associated on the surface of the container and extending over a main portion of the surface of the container, this coating has a first layer, comprising an acrylate sizing coating material and a second layer , on the first layer, comprising a mixture of a metal oxide and an inorganic oxide material.
2. 2. The assembly according to claim 1, further comprising a closure at the open end of the container, whereby an interface of the container and the closure is formed.
3. 3. The assembly according to claim 2, wherein the plastic container is a tube and the closure is an elastomeric stopper.
4. The assembly according to claim 1, wherein the multi-layer barrier coating includes saw teeth in correspondence, against violations, adjacent to the container interface and the closure.
5. 5. The assembly according to claim 1, wherein the first layer is a polymerized mixture of mono- and di-acrylates.
6. The assembly according to claim 1, wherein the second layer is a mixture of SnOx, GeOx or PbOx and a composition based on aluminum oxide or silicon oxide.
7. The assembly according to claim 6, wherein the second layer is deposited by a radiofrequency discharge, direct deposit of ion beams, double deposition of ion beams, electronic deposit, increased chemical vapor deposition of plasma or plasma magnetically increased.
8. The assembly of claim 1, further comprising a third layer, adjacent to the second layer, of a thermoset epoxy, parylene polymer, homopolymers, copolymers, polyesters or vinylidene chloride.
9. The assembly according to claim 8, wherein the first layer comprises the polymerized acrylate and the second layer comprises a mixture of tin oxide and silicon, and the third layer comprises the polyvinylidene chloride.
10. The assembly according to claim 1, further comprising a multilayer barrier coating on the inner surface of the container, having a first layer including an acrylate sizing coating material, a second layer, on the first layer, a mixture of metal oxide and an inorganic material.
11. 11. A multi-layer barrier coating, which comprises: a first layer comprising an acrylate material; and a second layer, on the first layer, comprising a mixture of a metal oxide and an inorganic oxide.
12. The coating of claim 11, wherein the second layer is a mixture of SnOx, GeOx or PbOx and aluminum oxide or silicon oxide.
13. The coating of claim 11, further comprising a third layer, on the second layer, of polyvinylidene chloride.
14. 14. A method for depositing a multilayer barrier coating on a plastic substrate, within a previously evacuated chamber, this method comprises: (a) selecting a curable component, which comprises: (i) polyfunctional acrylates or (ii) ) mixtures of mono-acrylates and polyfunctional acrylates; (b) rapidly vaporizing the component within the chamber; (c) condensing a first layer of a film of the vaporized component on the external surface of the container; (d) cure the film; (e) vaporizing an organic tin component and an organic silicon component and mixing these volatilized components, with an oxidizing component and, optionally, an inert gas component, to form a gas stream outside the chamber; (f) establishing an irradiation discharge plasma within the chamber, from one or more of the components of the gas stream; (g) controllably flowing the gas stream into the plasma, while confining therein at least a portion of the plasma; and (h) depositing a layer of a mixture of tin oxide and silicon oxide, adjacent to the first layer.
15. 15. The method according to claim 14, wherein the first and second layers are pretreated by the oxygen plasma.
16. 16. A method for depositing a barrier coating on a plastic substrate, within a previously evacuated chamber, this method comprises: (a) vaporizing an organic tin component and an organic silicon component and mixing these volatilized components, with a oxidizing component and, optionally, an inert gas component, to form a gas stream outside the chamber; (b) establishing an irradiation discharge plasma within the chamber, from one or more of the components of the gas stream; (c) flowing, in a controllable manner, the gas stream within the plasma, while confining therein at least a portion of the plasma; and (d) depositing a layer of a mixture of tin oxide and silicon oxide on the external surface of the container.
17. 17. The method according to claim 16, wherein the first layer is pretreated by the oxygen plasma.
18. 18. A method for applying a barrier film coating to the surface of the inner wall of a plastic substrate, this method comprising: (a) placing a plastic article having an open end, a closed end and a surface of wall, external and internal, so that the open end is connected to a vacuum manifold system having a monomer supply source, an oxidant supply source and a vacuum supply source; (b) placing the outer wall surface of the plastic article with an electrode assembly; (c) evacuate the interior of the article; (d) delivering a gas mixture of tetramethyltin monomers and HMDSO to the interior of the article; (e) deliver a radiofrequency power to the electrode of about 38 MHz and about 22 to 30 watts.
19. 19. A method for applying a bar film coating to the interior wall surface of a plastic substrate, this method comprises: (a) placing a plastic article having an open end, a closed end and a wall surface , external and internal, so that the open end is connected to a vacuum manifold system having a monomer supply source, an oxidant supply source and a vacuum supply source; (b) placing the external wall surface of the plastic article with an electrode assembly; (c) evacuate the interior of the article; (d) delivering a monomer gas mixture to the interior of the article; (e) delivering a radiofrequency power to the electrode; (f) ionizing the gases to thereby form a plasma, whereby a coating of bar film is applied to the inner wall surface of the container; (g) stopping the radiofrequency power of step (e); and (h) repeating steps (e) - (f).
20. The method according to claim 18, wherein step (d) further includes a diluent gas.
21. 21. A method for applying a bar film coating to the interior wall surface of a plastic substrate, this method comprises: (a) placing a plastic article having an open end, a closed end and a wall surface , external and internal, so that the open end is connected to a vacuum manifold system having a monomer supply source, an oxidant supply source and a vacuum supply source; (b) placing the outer wall surface of the plastic article with a set of electrodes; (c) evacuate the interior of the article; (d) delivering a monomer gas mixture to the interior of the article; (e) delivering a radiofrequency power to the electrode; (f) ionizing the gases, so as to form a plasma, whereby a coating of bar film is applied to the inner wall surface of the container; (g) stopping the delivery of gases from step (d); and (h) repeating step (d).
22. 22. The method according to claim 20, wherein step (d) further includes a gauze diluent.
23. 23. A method for applying a bar film coating to the inner wall surface of a plastic substrate, this method comprises: (a) placing a plastic article having an open end, a closed end and a wall surface , external and internal, so that the open end is connected to a vacuum manifold system having a monomer supply source, an oxidant supply source and a vacuum supply source; (b) placing the outer wall surface of the plastic article with a set of electrodes; (c) evacuate the interior of the article; (d) delivering a gas mixture of tetramethyltin monomers and HMDSO to the interior of the article; (e) delivering an air oxidizing gas to the interior of the article; (f) delivering a radiofrequency power to the electrode; (g) stopping the delivery of gases from step (d); (h) stopping the radiofrequency power of step (e); Y (i) repeat steps (d) - (h).