JP4426790B2 - High-speed processing method for making multilayer barrier layers - Google Patents

Description

  The present invention is for applying alternating layers by chemical vapor deposition (CVD), in particular plasma enhanced chemical vapor deposition (PECVD), in particular by plasma impulse chemical vapor deposition (PICVD). And a coating that can be deposited using this method.

  It is advantageous for this package to be provided with a barrier coating in order to reduce the gas and liquid and allow the package to be transparent to protect the package material from chemical attack or UV radiation. From this background, by way of example, depositing a thin SiOx coating or coating system on a polymer substrate, thereby reducing the oxygen and water vapor permeability in particular while maintaining the transparency of this material in particular. This is especially important for mass-produced plastics. Furthermore, the components of the material coated in this manner can generally be safely heated by a microwave device. A further advantage of this coating is its numerous options for depositing them on the polymer surface.

  However, to improve the quality of this type of coating, know the relationship between the barrier action of the layer, the morphological properties and the molecular transport through it, especially the effect of deposition conditions on the resulting coating parameters. It is necessary to control.

  Erlat et al. Mater. Res. , (2000) 15, pp. 704-716 present a model showing the relationship between barrier action and layer morphology and describe the effect of various processing parameters.

  Erlat et al. Phys. Chem. B (1999) 103, pp. 6047-6055 describe the morphology of the layer for a smooth surface based on the mode of the processing parameters. However, these recent references only consider individual inorganic barrier layers.

To improve the adhesion of a SiOx layer on a polymer substrate, Rupertus et al., Fresenius J. et al. Anal. Chem. (1997) 358, pp. 85-88 propose to treat the substrate in oxygen plasma.
Improvements to the coating process are performed in a conventional manner using process parameters of power, pressure and time.

  According to US Pat. No. 5,718,967 A1, first an oxygen-free adhesion-promoting layer is created by avoiding oxygen in the first layer, and then oxygen is introduced to bond under excess oxygen A protective layer can be formed on the promoting layer.

EP 709485 describes a method for the multilayer coating of plastic with alternating layers made from HMDSO and TiCl ₄ . In this method, an organic barrier layer is deposited using HMDSO, and an inorganic barrier layer is deposited using TiCl ₄ . However, this application describes how fast processing times can be achieved and how fast processing can be introduced into containers with> 18 ml, usually> 50 ml volumes. Absent.

In order to economically introduce barrier coating methods on substrates such as PET bottles, it is necessary to achieve very high throughput rates. The typical throughput rate of a line with a stretch blow molding machine for plastic containers and downstream filling equipment is 10,000 to 30,000 containers per hour. However, for optimal integration of barrier coating equipment arranged in this line in the following order:
1. Stretch blow molding 1. Coating filling

  It is necessary and advantageous to achieve a throughput speed that is comparable or exactly the same as that achieved with a barrier coating run. However, these framework conditions require a very fast barrier coating process, where the slight coating time for the layer to grow on the substrate is less than 6 seconds, preferably less than 3.6 seconds or less than 1.0 seconds You must

  The throughput speed is also determined by the number of stations required on the coating machine, which can be reduced by very short coating times, or in some cases at the same number of stations. This means that throughput speed can be increased, leading to significant cost advantages.

  WO 99/49991 describes barrier coatings containing amorphous carbon, where high speed processing with coating times in the range of 2-3 seconds is achieved. However, this document does not describe how a permeation or barrier improvement is achieved in a given processing time compared to an uncoated substrate. However, these layers are not transparent, rather they are brown to yellow in color. However, this coloration is very poor in appearance especially for transparent containers to be coated and often leads to unacceptable results. If these layers are deposited as thin films, the coloration is reduced but still exists. However, if the layer thickness is reduced, the barrier action is consequently significantly reduced. Furthermore, these layers of amorphous carbon can only be removed from PET substrates with great difficulty and at high cost. For this reason, a problem arises in the reuse of the coated container because a certain amount of color may remain in the recycled product even if it is mixed with uncoated PET.

  A coating time of 2-4 seconds for the SiOx barrier layer is also described in patents WO 02/09891 A1 and WO 02/10473. However, these publications do not mention processing parameters that can be used to achieve the specified coating times. In particular, accurate information is also lacking regarding pressure, concentration, microwave power, and precursor flow rates, as well as carrier and reactive gas flow rates.

  Furthermore, WO 02/10473 has deposited multiple layers of various starting compounds, which have amorphous carbon, SiOx layers, and a boundary layer made from oxygen and “organosilicon containing” compounds for the substrate. A method including a protective layer is described. This method is highly complex because a total of three layers are deposited and very different starting compounds must be used. Claims 1 to 10 of WO 02/09891 A1 likewise describe a complicated method.

Erlat et al. Mater. Res. (2000) 15, 704-716. Erlat et al. Phys. Chem. B (1999) 103, 6047-6055 Rupertus et al., Fresenius J. et al. Anal. Chem. (1997) 358, 85-88 US Pat. No. 5,718,967 A1 European Patent No. 709485 International Patent No. 99/49991 International Patent No. 02/09891 A1 International Patent No. 02/10473 PCT / EP / 0208553 Reference number 02SGL0184DEP “Process for producing smooth barrier layers and composite material with smooth barrier layer”

  It is this book to work on the basis of the known methods mentioned above and to provide a method that can be optimally integrated in a production line to deposit a high quality barrier layer on a substrate such as the inner surface of a plastic bottle. It is an object of the invention.

This object is achieved in a surprisingly simple manner by the features of claim 1. Furthermore, claim 33 provides a composite material that can be made using the method according to the invention.
Advantageous refinements are given in the respective dependent claims.

  The Applicant has already described a method of making a composite material with improved barrier action and improved adhesion in the application PCT / EP / 0208553 entitled “Composite material compiling a substrate material and a barrier layer material”. Proposed. The reference material of this application PCT / EP / 0208553 has been prepared, and the full text of the reference material and any protection rights derived therefrom are also incorporated herein during this application.

  In the method according to the invention, alternating layers are simply made from one precursor or two silicon-containing precursors. This allows a procedure that is fast and simple to install, and in particular makes it possible to achieve the fast processing times according to claim 1.

  The transition between organic and inorganic layers can be made variable, and furthermore, very smooth layers can be deposited, and the barrier action is enhanced by the interface between the organic and inorganic layers. The

  The present invention provides an overall flow rate for the inorganic layer, the second layer, that is greater than or equal to the overall flow rate for the organic adhesion promoting layer, the first layer. In the latter case, it is then advantageously possible to significantly increase the deposition rate of the second layer so that the overall coating time can be further reduced. Increasing the overall flow rate with a low precursor concentration allows the deposition rate to be significantly increased while maintaining the barrier layer quality, thereby maintaining the same layer thickness while maintaining the second layer thickness. Significantly reduced coating times are possible for these inorganic barrier layers.

  Thus, the solution according to the invention for the first time is an alternating layer, i.e. at least 2 by CVD, preferably PECVD, in particular PICVD, which includes the processing steps of rapid deposition of an adhesion promoting layer and barrier layer deposition on the substrate. A method for providing two layers is provided, wherein alternating layers of organic and inorganic materials are alternately deposited. Preferably only two layers are deposited. This makes it possible to achieve particularly fast processing times.

  The alternating layers are for a single precursor gas, or for example hexamethyldisiloxane or hexamethyldisilazane for two layers, or hexamethyldisiloxane for the first organic layer and the second inorganic layer It may be advantageous to deposit from two similar silicon-containing precursor gases such as hexamethyldisilazane.

  The method states that the coating time for depositing the adhesion promoting layer is between 0.05 seconds and 4 seconds and / or the coating time for depositing the barrier layer is between 0.1 seconds and 6 seconds. Differentiated by facts. In this context, the term “coating time” refers to the time interval during which layers are deposited on a substrate, during which a continuous or pulsed plasma is lit.

  In particular, to efficiently create a barrier layer on a dielectric material, it is necessary to deposit a smooth layer with a low density at the inner interface or other heterogeneous portion. A high density of phase or chemical heterogeneity can lead to increased permeability of the layer.

  This is especially the case if there is a short diffusion path through which rapid diffusion with respect to deposition can occur along its heterogeneous part. By way of example, it is generally impossible to achieve an excellent barrier action with a very porous layer. Accordingly, a layer having a low density of short diffusion paths such as an amorphous layer having a low density internal interface and / or a polycrystalline layer having a low density grain boundary is preferable.

With alternating layers, diffusion through the interface between the organic and inorganic layers is significantly inhibited or the diffusion path is significantly lengthened.
Both a very smooth inorganic layer and a very smooth organic layer can be deposited with appropriately selected processing parameters. On the same date, the applicant was issued with the title “Process for producing smooth barrier layerers and composite material with smooth barrier layer”, and was added with the reference number 02SGL0184DEP of the applicant after the official reference number 02SGL0184DEP Applicants have proposed an apparatus and method for creating alternating layers of extremely smooth barriers. The full text here is incorporated into this application as reference material.

  In order to allow extremely fast processing according to the invention to be carried out in a simple manner, alternating layers according to the invention are deposited by varying at least one processing parameter.

  The inventor has found that by using a plasma enhanced CVD method, in particular the so-called PICVD method, it is possible to deposit a layer with particularly good adhesion and excellent barrier action in a very short processing time. It was. PICVD technology can be used to deposit layers that are very thin on the substrate material but still have very good barrier properties. In addition, these layers are highly flexible.

The use of the PICVD method also allows the method to be used in a multi-station apparatus that specifically allows high throughput.
In the method according to the invention, a plasma generated by microwaves is advantageously used for the deposition of the layers. In this background, it is preferable to use a microwave with a frequency of 2.45 GHz. In addition, there is provision to pulse the plasma generated by microwaves.

  The increased overall flow rate causes a change in the flow profile within the container. Depending on the gas flow rate for the inorganic barrier layer in particular, the lance length at which the precursor gas is introduced into the container to be coated is conveniently adjusted, thereby achieving a uniform distribution of the components of the processing gas in the container. It is possible. Lance length is defined in this case as the distance between the opening through which gas flows into the container to be coated and the outer edge of the container opening of the container to be coated, which is sealed with respect to the atmosphere. During this adjustment, the layer thickness distribution for the organic layer changes only slightly.

  In addition to the lance length, the present invention also provides an interpulse period that matches the increased overall flow rate. In this case, the interpulse period is shortened as the overall flow rate increases.

  The period between pulses determines the time during which fresh process gas can enter the vessel before the plasma is ignited and coating occurs. With a flow optimized for pressure, overall flow rate, precursor concentration, lance length and nozzle diameter, it is possible to achieve a good distribution of the components of the process gas even with a relatively short interpulse period, In this way, the processing procedure can be further accelerated.

  It should be noted that when using a pulsed plasma, the deposition rate is not necessarily lower than when using what is known as “continuous wave plasma (CW plasma)”, because If a properly determined parameter is used for the pulsed plasma, a substantially complete conversion of the material can occur in the pulse length, and also substantially between the next pulses Fresh fresh gas, which is completely converted to, flows in during the interpulse period.

  If fresh process gas flows in at the right time and then a higher quantitative conversion of material occurs between pulses with higher pulse power than in the case of CW plasma with lower instantaneous power The deposition rate achieved with a pulsed plasma can even be higher. Furthermore, by shortening the period between pulses, the deposition rate can be increased significantly to an optimum value, since an increase in the proportion of unconverted precursor gas to the saturation point is reached.

  According to the invention, the deposition rate for the organic layer is in the range of 120 nm / min to 5000 nm / min, preferably in the range of 500 nm / min to 2000 nm / min, and / or the deposition rate for the inorganic layer is 60 nm / min to 2000 nm / min. The range is min, preferably 100 nm / min to 1000 nm / min.

  Therefore, by shortening the period between pulses, it is possible to achieve a significantly shorter coating time while forming an optimum level, because if the period between pulses is too short, the process gas components are uniform. This is because the uniformity of the coating becomes inadequate due to the fact that it is impossible to form a uniform distribution.

Uniformity is defined as the ratio of the minimum layer thickness to the maximum layer thickness, the value of which is determined by measurements across the substrate described above.
On the other hand, if the period between pulses is too long, the ratio of unconsumed process gas increases. According to the present invention, the lance length decreases as the overall flow rate increases. The lance length is 5% to 80%, preferably 10% to 50% of the height of the hollow body to be coated.

  A further advantage of the pulsed plasma is that, unlike CW plasma, unwanted organic reaction products are removed in the inter-pulse period, resulting in a significantly reduced proportion of organic components incorporated into the layer. It is possible to produce a pure inorganic barrier layer.

  In addition to the advantages of the PICVD method described above, the possibility therefore further increases processing parameters to control the process of rapid deposition of alternating layers from a single precursor gas or two similar silicon-containing precursor compounds. Can be supplied.

  The at least one processing parameter to be changed is selected from the group consisting of precursor concentration, average microwave power, pressure, pulse power, pulse length, interpulse period interval and overall flow rate. These parameters make it possible to deposit a high quality barrier layer despite the use of very short coating times. All of the processing parameters described relate to the coating of individual substrates. For the coating of multiple substrates in a multi-position apparatus, for example a rotary or batch apparatus with multiple chambers, the parameters described in each case relate to the coating in individual chambers.

  For organic layers, the optimal inter-pulse period has proven to be in the range 2 ms to 100 ms, preferably between 5 ms and 60 ms, and for inorganic layers between 5 ms and 200 ms, preferably between 20 ms and 50 ms. Was proved.

According to the invention, these parameters are set to optimum values for this purpose.
In particular, the precursor concentration for the deposition of the first organic adhesion promoting layer is in the range of 5% to 80% of the total stream and / or the precursor concentration for the deposition of the second inorganic barrier layer is It is provided to be in the range of 0.5% to 4% of the stream, preferably between 0.8% and 3%.

  Furthermore, the pulse power for the organic layer is in the range of 100 W to 5000 W, preferably in the range of 400 W to 1500 W, and / or the pulse power for the second inorganic layer is in the range of 100 W to 5000 W, preferably from 400 W. It is prepared to be in the range of 1500W.

  According to the invention, the average microwave power for the organic layer is in the range of 10 W to 5000 W, preferably in the range of 10 W to 500 W and / or for the inorganic layer in the range of 10 W to 5000 W, preferably 30 W to 2000 W. Is in range.

  The barrier coating may also be particularly advantageous to have a structure or composition that varies in a direction perpendicular to the coating surface of the substrate. In this case, this change can be continuous or stepped.

Step changes lead to multi-layer barrier coatings. By way of example, the bottom layer in contact with the surface of the substrate may be used as an adhesion promoting layer for subsequent coatings. Multiple layers or layer series of this type can be made, for example, by continuous or stepwise changes in precursor concentration during coating.
In this case, particularly good coating properties can be achieved with multiple alternating layers known as multiple layers.

  The substrate material to be coated can also have a hollow body in particular. The method according to the invention thus makes it possible to deposit a coating on the inside and / or outside of the hollow body.

  The applicant of the present application filed with German Patent and Trademarks Office on the same date is “Process for producing smooth barrier layers and composite material whistle with the title of the title of the document, as a reference material of EP 84 as a reference material of the document“ Layman ’s body with the title of the title of the document, the semi-manufactured material, as the reference material of the EP, 84 Describes an apparatus for depositing a barrier layer. The disclosure of this application is made here by reference in its entirety, and the contents of this application are incorporated by reference in its entirety in the subject matter of this application.

The invention also preferably supplies a hollow body as a substrate which is simultaneously evacuated to the pressure P _{1 on} the outside and pumped to the base pressure P ₂ <P ₁ on the inside, the pressure P ₁ being in particular about 50 mbar. And the base pressure P ₂ is particularly preferably less than 0.1 mbar.

Furthermore, with regard to the method according to the invention, P ₂ <P ₃ <P ₁ , especially for the first organic layer, the pressure P ₃ is in the range from 0.1 mbar to 1.0 mbar, preferably from 0.2 mbar. in the range of 0.5 mbar, for the second inorganic layer is in the range of 1.0mbar from 0.1 mbar, preferably in the case of the in the range of 0.6mbar from 0.25 mbar, group at a pressure _{P 3} A gas mixture is provided that includes precursors that enter the interior of the material. The advantageous result of this is that the thin wall material case can lead to deformation of the hollow body and the pressure differential acting on the wall of the hollow body is not excessive.

  Furthermore, in order to coat the inside exclusively, it may be advantageous to select the outside pressure in such a way that the plasma does not ignite on the outside. In order to avoid a large pressure difference even during pump exhaust, the pump exhaust operation is carried out uniformly initially so that the aforementioned outer pressure is reached and then only the inner side until a base pressure within the aforementioned range is reached. It can be expedient to pump further.

In this method, the overall flow rate during deposition of the inorganic barrier layer and / or the pressure P ₃ inside the substrate is the overall flow rate during deposition of the organic adhesion promoting layer and / or the pressure P ₃ inside the substrate. Conveniently at least equal to, and more specifically, more. Thus, the present invention makes it possible to achieve a deposition rate during deposition of the inorganic barrier layer that is significantly higher than with a lower overall flow rate.

According to the present invention, the process gas for the layers it is allowed a higher pressure P ₄ than the pressure P ₅ in the previous plasma ignition. In this manner, the filling operation can be performed quickly and efficiently. Thereafter, during layer deposition, the processing pressure is continuously reduced until the next layer deposition begins, and the temperature continues to rise while the coating is being applied.

  According to the present invention, the overall flow rate for the organic adhesion promoting layer is in the range of 10 sccm to 250 sccm, preferably in the range of 40 sccm to 100 sccm, and for the inorganic layer is in the range of 200 sccm to 1000 sccm, preferably in the range of 250 sccm to 400 sccm. .

  Furthermore, the method is distinguished by the fact that when process parameters change during the transition between the two coating steps, the plasma either continues to light or is interrupted during the transition. As a result, the present invention makes it possible to achieve a smooth and continuous transition in a gradient form, or a stepped abrupt transition, and to save energy. In particular, for pulsed plasma, the transition time is longer than the period between pulses.

The method according to the invention in principle eliminates the need for pretreatment of the substrate. In the case of particularly stringent substrates, for example made of materials with poor coating adhesion, however, it is also possible with this method to pretreat with plasma prior to coating deposition. Nevertheless, the duration of the plasma pretreatment is less than 5 seconds, preferably less than 1 second, in order to ensure that the high speed of the treatment according to the invention is not consequently reduced.
There are further provisions to change the combination of processing parameters in order to expand the possible options for control of the process and to make it possible to exploit synergies.

  Depending on the requirements imposed on the coating, the method according to the invention may be used to make layers with different properties. For example, one requirement may be the creation of an interface defined within the coating, particularly with respect to improved barrier action. Thus, the solution according to the invention has various options for changing the processing parameters. At least one processing parameter can be varied continuously or discontinuously, or in some cases, at least one processing parameter can be partially varied and / or partially discontinuous. It is also possible to change to

  In the case of the method according to the invention, it is expedient to first deposit an organic layer as an adhesion promoting layer on the substrate. This makes it possible to improve the adhesion of further layers, in particular barrier layers.

  The precursor is fragmented during the deposition of the adhesion promoting layer. Appropriate selection of processing parameters can be achieved in such a way that individual fragments in the form of atoms, molecules, ions or free radicals react with the molecules of the substrate to be coated to form chemical bonds (chemisorption) Affects fragmentation. This bond is preferably physical adsorption. The strong bond resulting from fragmentation of the precursor improves the adhesion of the layer. In particular, fragmentation leads to the formation of an organic adhesion promoting layer when the carbon content exceeds 10%.

  Furthermore, the processing parameters influence the growth of the adhesion promoting layer in such a way that the organic layer is conveniently deposited on the substrate by individual layer growth and has very few defects in the form of internal interfaces. Thus, the adhesion promoting layer is very smooth and can itself have a barrier action because it has very few interfaces that can act as a path for rapid diffusion. It is.

  In addition, an adhesion promoting layer can be used to establish the effect of smoothing a rough plastic substrate under appropriate conditions. Against this background, the entire text of the application 02SGL0184DEP in the name of the applicant is used as reference material. One advantage of a smooth adhesion promoting layer is that an inorganic layer with an excellent barrier action can be deposited on it, whereas an adhesion promoting layer with a rough morphology has a significantly reduced barrier action. Only an inorganic layer can be deposited. The inorganic barrier layer used is sufficient for good layer adhesion, even in the case of non-polar plastics such as polypropylene. One advantage of this background processing technique is that the method according to the present invention is a time-consuming plasma pretreatment performed, for example, using an oxygen plasma, according to previously cited documents, to activate the surface. It is not necessary.

  According to the method of the present invention, the inorganic layer is deposited as a barrier layer. This barrier layer advantageously improves the barrier action because of the interface between the organic layer and the dense, similarly smooth inorganic layer. A sudden change in morphology, such as a change from individual layer growth to columnar or island growth, significantly lengthens the diffusion path along the interface. Furthermore, the bonding state is more varied at the interface than inside the layer, making transmission more difficult in these regions.

The method according to the present invention can be performed using a variety of precursors, in particular, an organic silicon-containing or metal-containing organic compounds, in particular HMDSN, HMDSO, TMDSO, silane in _{N 2,} TEOS or TIPT or, There is provided a gas mixture comprising oxygen, at least one precursor selected from the group consisting of metal chlorides, in particular TiCl ₄ , or silicon chlorides, and hydrocarbons, in particular alkanes, alkenes or alkynes, in particular acetylene. Preferred precursors in this case are HMDSN and / or HMDSO.

By repeating the processing steps of depositing the first layer and the second layer, alternating layers are deposited in particular on the dielectric material and / or plastic, so that the method according to the invention has a barrier with a particularly long diffusion path. A coating can be deposited, in which case it may be advantageous to use the method in packaging, in particular plastic packaging.
In addition to the present method, the present invention also includes a composite material having alternating layers of alternating organic and inorganic materials deposited from a single precursor gas.

  Furthermore, the composite material advantageously has improved barrier action, improved adhesion to the substrate, improved stretchability, improved mechanical stability under compressive load and / or improved mechanical stability under tensile load. Have sex. After tensile and / or plastic deformation with a length change of more than 4%, the improvement of the barrier is maintained in the case of the composite material according to the invention, and the improvement of the oxygen barrier is a factor of more than 1.5, preferably 2.0. It is a factor that exceeds.

  Another advantage of this composite material is that it has high mechanical stability, especially under tensile loads caused by carbon dioxide saturated liquids under pressure. Containers made from the composite material according to the invention are particularly suitable for this type of liquid. Thus, the coating according to the present invention generally provides advantages when it is used on a substrate comprising or forming a container for foamed products or products with dissolved gas.

  The coating has at least one organic adhesion promoting layer, the thickness is in the range of 1 nm to 200 nm, and has at least one inorganic barrier layer with a thickness of 5 nm to 200 nm.

  The present invention initially makes it possible to create a layer quality within a rapid processing time of less than 6 seconds, which has a barrier action, adhesion, stretchability, even in the range of layer thicknesses listed. And excellent enough that the demands placed on mechanical stability under compressive load conditions can be met.

  Material savings are possible due to the small layer thickness required. Furthermore, the coating time required can be reduced since the coating time can be selected shorter and shorter as the layer becomes thinner. In this way, the coating according to the invention makes it possible to use extremely fast coating processes with a surprisingly high barrier action quality.

  Furthermore, the composite material is temperature resistant. Temperature resistance is defined by the fact that layer bonding and barrier action exist even after high temperature filling. Thus, particularly under the heat load caused by hot filling, the present invention provides the advantage that there is substantially no delamination of the barrier coating caused by the heat load and that an excellent barrier action still exists after the heat load. .

  Furthermore, the coating according to the present invention has excellent resistance to filling hot liquids as required, for example, in HOT-FILL bottles or other product containers used for hot filling. In these containers too, the process can be introduced with very short coating times.

In addition to at least one alternating layer having an organic coating and an inorganic coating, the composite material can also include a cover layer. For example, a protective layer can be provided depending on the requirements imposed on the coated substrate.
In addition, the cover layer may have a display or other such configuration written on the coated substrate.

  Unlike conventional processing using carbon as the main raw material, the composite material according to the present invention is substantially transparent. The term “transparent” means a layer that is transparent in the visible wavelength region, which means that the visual transmission (light type D65) is not lower than an uncoated bottle. Thus, the present invention is used to make a container that allows the product to be viewed from the outside in a first undistorted form and secondly to allow visual observation of the contents. Can do. This may be important in medical technology or biotechnology, for example for application in spectroscopic measurements.

In the field of food or cosmetic packaging, firstly transparent packages are attractive to consumers, and secondly the contents of such packages are easily and reliably checked for damage. It can be done well.
In the following, the invention will be described on the basis of exemplary embodiments with reference to the attached drawings.

Inner Coating of 0.4L PET Bottle with Adhesion Promoting Layer / Barrier Composite Made of polyethylene terephthalate (PET), a bottle with a fill volume of 0.4L is evacuated to a pressure of 50 mbar on the outside and at the same time on the inside To a base pressure below 0.1 mbar.
Thereafter, a mixture of oxygen and hexamethyldisilazane (HMDSN) enters the interior of the bottle at a pressure of 0.3 mbar.

Thereafter, pulsed microwave energy having a frequency of 2.45 GHz is introduced and a plasma is ignited in the vessel.
Initially, a first 10 nm thick organic barrier layer is deposited with a coating time of less than 1 second, 40% HMDSN concentration, and a total flow rate of 40 sccm.

The pulse power is 800 W, the pulse length is preferably 0.7 ms, and the period between pulses is 40 ms.
This is followed by a rapid gas change to a lower HMDSN concentration of 1.2%. A second inorganic barrier layer is deposited at the same predetermined pressure.

  Sorting tests with constant HMDSN concentration and constant pressure, statistics of layer thickness and / or coating time parameters, oxygen flow rate and pulse power, further processing parameters of pulse length and interpulse period, and lance length, which is an instrument parameter Can be changed according to the test plan.

FIG. 1 shows the contrast between the set oxygen flow rate and the measured deposition rate.
As the oxygen flow rate increases, the deposition rate of the second inorganic layer can be significantly improved.
Table 1 shows the selection of processing parameters tested for the second inorganic layer, where the composite material comprising the first and second layers leads to a high barrier action.

In addition, the coating time and deposition rate of the second inorganic layer are shown as a function of processing parameters and equipment parameters, and the two-layer composite comprising the first organic layer and the second inorganic layer immediately after coating and load test ( (Creep test using 4% by volume of CO ₂ ).

In the above table, the barrier enhancement factor BIF is defined as the ratio of the permeability of the uncoated substrate to the permeability of the coated substrate.
From the data, it can be seen that a deposition rate of 86 nm / min is achieved in Process 1 with an oxygen flow rate of 100 sccm, a period between pulses of 50 ms, and a lance length of 102 mm.

The coating time is relatively long, 14 seconds. In contrast, due to the high oxygen flow rates of 220, 380 and 450 sccm, and the shortening of the interpulse period to 40 ms, and the improved 50 mm lance length, the deposition rates of treatments 2, 3 and 4 were significantly higher, respectively. 200, 318 and 360 nm / min.
Thus, the coating time can be significantly reduced.

  In addition, the thickness of the second layer was reduced to further reduce processing time. This led to an overall reduction in the resulting coating time from 2 to 6 seconds.

This coating makes it possible to make an adhesion promotion / barrier complex with a high oxygen barrier enhancement factor (O ₂ -BIF) having a value significantly above 40 for treatments 1, 2 and 3.
The transmittance of the uncoated bottle is 0.1955 cm ³ / (package · day · bar). The transmittance of the coated bottle is so low that it does not reach the resolution limit of the measuring device Mocon-Oxtran used.

For treatment 4 with the shortest coating time of 2 seconds in the second layer, 30 O ₂ -BIF was determined.
These layers have very good adhesion and tensile resistance, as shown by the following creep test.

For the creep test, the coated bottle was filled with 0.4 L of liquid saturated with carbon dioxide and having a CO ₂ content of 4% and sealed with a plastic cap. The filled bottles were then initially stored at room temperature for 24 hours and subsequently stored at 38 ° C. for 24 hours.

  The test procedure resulted in an internal pressure of up to 5 bar in the bottle, so that the layer / substrate assembly was locally stretched above 4.5% and even led to plastic deformation. High levels of stretching and / or plastic deformation reduce the barrier improvement, which can be traced to changes in the layer composite in a very high stretch range.

  However, the complex is stable enough to retain an easily detectable barrier action despite this high load. This effect, despite the high level of stretching and / or plastic deformation, does not result in delamination due to excellent adhesion, and counteracts the barrier action on the layer composite for most of the coated surface. It can be attributed to the fact that the cracks that would give are not formed.

O ₂ -BIF is determined again after the creep test. The judgment values are shown in Table 1. Processes 2 and 3, which are considerably shorter than process 1, allow for a relatively good barrier action and make it possible to achieve a slightly improved barrier action even after the creep test as compared to process 1.

  The fastest treatment has a somewhat lower but still very high barrier improvement after coating, and just the same excellent barrier improvement as the slower treatment 1 after the creep test.

Alternate layers with alternating organic and inorganic layers The process of the first exemplary embodiment is repeated several times to deposit alternating layers with alternating organic and inorganic layers.
After the organic barrier layer is deposited, a rapid gas exchange takes place, an inorganic barrier layer is deposited, further gas changes are made, during which the organic layer coating parameters are established.

  Thereafter, the operation including the described steps is repeated at least once. The deposited alternating layers have high barrier action and very good mechanical load bearing characteristics.

High speed coating of HOT-FILL bottles HOT-FILL bottles made from crystalline PET and having a volume of 0.5 L are coated using the same processing parameters used in Process 2 of Example 1. In this case, the term HOT-FILL bottle is conventional and can be filled with a hot liquid and changes in size substantially when filled with a liquid between 85 ° C and 95 ° C. It means a bottle that is not affected.
However, the deposition rate changes due to the changed bottle shape.

  In order to coat the bottle with substantially the same layer thickness as in Example 1, results are obtained that require a coating time of 1.3 seconds for the first organic layer and 5.3 seconds for the second inorganic layer. .

Immediately after coating, the container has a high barrier action. The uncoated HOT-FILL bottle has an oxygen transmission rate of 0.192 cm ³ / (package · day · bar), and the coated bottle has an oxygen transmission rate below the detection limit of 0.04 cm ³ / (package · day · bar). And thus has an O ₂ -BIF greater than 40.

  In the load test, the coated bottles are initially stored for 1 hour at 35 ° C. and 95% relative atmospheric humidity. The bottle is then filled with 95 ° C. water to a level of 0.5 L and the temperature is held at this level for 5 minutes, after which the filled bottle is cooled to room temperature in a cold water bath for 20 minutes.

After this hot filling load test, the oxygen permeability of the sample is determined.
The result for this case is 9 for O ₂ -BIF after the load test. This test shows that the coating can withstand high temperature filling because no delamination is observed and excellent barrier action is maintained after high temperature filling.

High speed internal coating of 0.6 L PP bottles with adhesion promoting / barrier composite Coating a bottle made of polypropylene (PP) using the same processing parameters as in treatment 2 of Example 1 and having a fill volume of 0.6 L . The deposition rate changed due to the changed bottle shape.

In order to coat the bottle with the same layer thickness as in Example 1, results are obtained that require a coating time of 1 second for the first organic layer and 5.6 seconds for the second inorganic layer. This coating makes it possible to make an adhesion promotion / barrier complex with a high O ₂ barrier enhancement factor (O ₂ -BIF).

  These layers are very strongly deposited and can withstand pulling. In this case, there is no need for plasma pretreatment or activation of the substrate, as is done for example by oxygen plasma.

FIG. 5 shows the deposition rate of the second inorganic barrier layer as a function of oxygen flow rate.

Claims (34)

A method for depositing alternating layers by chemical vapor deposition, comprising:
Depositing an organic adhesion promoting layer on the substrate and depositing an inorganic barrier layer, wherein alternating layers of organic and inorganic materials are alternately deposited by one precursor material to form an organic adhesion A promoter layer is deposited as the first layer and an inorganic barrier layer is deposited as the second layer to produce a transparent composite material and a precursor concentration for the deposition of the organic adhesion promoter layer is The precursor concentration for the deposition of the barrier layer is in the range of 0.5% to 4% of the total flow, and the total flow rate for the inorganic layer is in the range of 200 sccm to 1000 sccm. The coating time for the deposition of the organic adhesion promoting layer is between 0.05 and 4.0 seconds and / or the coating time for the deposition of the inorganic barrier layer is 0.1 seconds. Ri near for 6.0 seconds, the organic layer How have is the deposition rate is in the range of 5000 nm / min from 120 nm / min, and the deposition rate for the inorganic layer is in the range of 60 nm / min of 2000 nm / min.
The method of claim 1, wherein alternating layers are deposited by varying at least two processing parameters.
The method according to claim 1, wherein a plasma generated by a microwave having a frequency of 2.45 GHz is used for the deposition of the layer.
The method of claim 3, wherein the plasma generated by the microwave is pulsed.
The method according to claim 1, wherein the alternating layers are deposited by PECVD (plasma enhanced chemical vapor deposition).
The process parameter to be changed is selected from the group consisting of precursor concentration, average microwave power, pressure, total flow rate, pulse power, pulse length, and duration of interpulse period. The method according to claim 1.
7. A method according to any one of the preceding claims, wherein the precursor concentration for barrier layer deposition is between 0.8% and 3% of the total stream.
8. A method according to any one of the preceding claims, wherein the interpulse period for the organic layer is between 2 ms and 100 ms, and for the inorganic layer is between 5 ms and 200 ms.
9. Pulse power for the organic layer is in the range of 100W to 5000W and / or pulse power for the second inorganic layer is in the range of 100W to 5000W. the method of.
10. The average microwave power for the organic layer is in the range of 10W to 5000W and / or the average microwave power for the inorganic layer is in the range of 10W to 5000W. The method described.
The substrate is a hollow body that is simultaneously evacuated to the pressure P _{1 on} the outside and pumped to the base pressure P ₂ <P ₁ on the inside, the pressure P ₁ being in the range of 1000 Pa to 5000 Pa , and the pressure P ₂ The method according to claim 1, wherein is less than 100 Pa .
Gas mixture comprising _precursor, a _{P 2 <P 3 <P 1} , into the interior of the substrate at a pressure _{P 3} when the pressure _{P 3} in the range of 100Pa from 20 Pa, any of claims 1 to 11 The method according to claim 1.
The total flow during the deposition of the inorganic barrier layer and / or the pressure P ₃ inside the substrate is at least equal to the total flow during the deposition of the organic adhesion promoting layer and / or the pressure P ₃ inside the substrate; 13. A method according to any one of claims 1 to 12, which is higher than specified.
In the range pressure _{P 3} from 10Pa to 100Pa for the first organic layer, and the second inorganic layer is in the range of 100Pa from 10Pa, the method according to any one of claims 1 to 13 .
15. A method according to any one of the preceding claims, wherein the lance length is in the range of 5% to 80% of the height of the substrate to be coated.
16. A method according to any one of the preceding claims, wherein the total flow rate for the organic adhesion promoting layer is in the range of 10 sccm to 250 sccm and the total flow rate for the inorganic layer is in the range of 250 sccm to 400 sccm. .
In case the process gas is each for layer, is allowed to be in the high pressure P ₄ than the pressure P ₅ in the immediately preceding ignition of the plasma, the method according to any one of claims 1 to 16.
18. A method according to any one of the preceding claims, wherein the process pressure continues to drop between layer depositions until the next layer deposition begins.
19. A method according to any one of the preceding claims, wherein the temperature continues to increase during the deposition of the coating.
20. The plasma continues to be lit while the processing parameters are changing during the transition between two processing steps: depositing an organic adhesion promoting layer on the substrate and depositing an inorganic barrier layer. The method according to claim 1.
During the transition, the plasma is interrupted, which is between 0 and 1.0 seconds, between two processing steps: depositing an organic adhesion promoting layer on the substrate and depositing an inorganic barrier layer. 20. A method according to any one of the preceding claims, wherein processing parameters are changed during the transition.
The method according to any one of claims 1 to 21, wherein for a pulsed plasma, the transition time is longer than the period between pulses.
23. A method according to any one of the preceding claims, wherein a plasma pretreatment is carried out with a duration of less than 5 seconds before depositing the coating.
24. A method according to any one of the preceding claims, wherein at least one processing parameter is varied continuously.
25. A method according to any one of the preceding claims, wherein at least one processing parameter is varied discontinuously.
26. A method according to any one of the preceding claims, wherein the at least one processing parameter is varied partly continuously and partly discontinuously.
Gas mixture, oxygen and comprises at least one of hexamethyldisilazane as the silicon-containing organic compound (HMDSN) and / or hexamethyl solo hexane (HMDSO), according to any one of claims 1 to 26 Method.
Processing step of depositing a first layer and the second layer is repeated, the method according to any one of claims 1 to 29.
29. A method according to any one of claims 1 to 28 , wherein alternating layers are deposited on the dielectric material.
30. The method of claim 29 , wherein alternating layers are deposited on the plastic.
A substrate, a composite material comprising at least one alternating layer comprising a coating of organic and inorganic, in the composite material is deposited using a method according to any one of claims 1 to 30, the coating Compared to materials that are not, but otherwise identical, are distinguished by increased barrier action, and after tensile and / or plastic deformation with a length change of more than 4%, the barrier improvement is maintained and the oxygen barrier The improvement of the composite material is a factor exceeding 1.5 .
32. The composite material according to claim 31 , wherein the organic adhesion promoting layer has a thickness of 1 nm to 200 nm and / or the inorganic barrier layer has a thickness of 5 nm to 200 nm.
33. A composite material according to claim 31 or 32 comprising a cover layer in addition to at least one alternating layer having an organic and inorganic coating.
34. A composite material according to any one of claims 31 to 33 , which is substantially transparent.

Images