DE102004054938A1 - Stretch blown or extrusion blown internal coated plastic container manufacture, involves pre-inflation with gas, followed by final inflation with ignited combustible gas containing substances to form barrier layer - Google Patents

Abstract

A plastic preform is introduced into a tool and inflated with pressurized gas to create an intermediate container. Pressure in the container is then reduced to that of the surrounding environment. Barrier layer forming substances are added to a combustible gas which is introduced into the container and ignited to increase pressure and produce the final container shape. During ignition the layer-forming substances take the shortest path to the wall of the intermediate or final container to form an internal diffusion barrier. After reducing pressure in the intermediate container(1) a dry gas may be pumped in under pressure and then extracted. In a variation of the process a precursor layer comprising one or more layer forming substances in fluid, paste or melt form is applied onto the inside of the preform or the intermediate plastic container. Combustible gas burnt in the container forms a diffusion barrier layer. An independent claim is included for the process equipment which includes a gas igniter(3) extending into the intermediate or final containers with at least two ignition points(2,2', 21,22). Distribution of the ignition points over the length of the ignition lance depends on the container dimensions. Maximum spacing of individual ignition points from each other and from the adjacent wall is equal to the radius(41), but is preferably less than the radius length.

Description

The The invention relates to a method for the production of hollow plastic bodies, the during or Immediately after forming by blow molding under action a combustion of a gas mixture in the interior with a diffusion barrier layer against gases and vapors be provided.

In DE 101 14 401 describes a method for blow molding a container made of plastic and for coating the container interior, in which a preheated preform preformed by a low pressure between 2 and 15 bar injected gas enlarging its volume to an intermediate molded container and by igniting a blown, combustible gas Generation of a high pressure is formed in its final shape. It is further provided to provide the inside of the container with a barrier to gases and flavorings by the combustible gas, a precursor gas consisting of at least one silicon, magnesium, aluminum, titanium, zinc, zirconium or boron compound or a mixture thereof, and the resulting mixture is ignited to convert said compounds into a silica, silica oxynitride, magnesia, alumina, titania, titanium nitride, zinc oxide, zirconia or boria based coating or the like ,

adversely Here is the risk of dust or sand formation due to premature reaction of the precursory gas within the gas phase in competition with the stratification reaction, whereby no sufficiently diffusion-tight barrier layer is formed. Other embodiments see the same font therefore to avoid dust formation in the gas phase, applying a precoat within the preform or container before that afterwards by ignition a fuel gas mixture is converted into a diffusion barrier layer. Here, the pre-layer is a single or multi-stage combustion process under Involvement of oxygen or ozone. It will not be Teaching indicated, in which case the pre-layer without Diffusionsssperrwirkung converted into a diffusion barrier layer of high effect shall be. In particular, it does not name which chemical Links especially for the conversion from a pre-layer to a diffusion barrier layer suitable.

In DE 101 18 242 is a very similar method is called with device in which a hollow body is provided on the inside with a barrier to diffusion and permeation by means of detonation of a detonatable gas mixture containing a gaseous precursor for the layer to be formed. Here it is also proposed that a mixture of oxidizing gas and precursors readily combustible gas is used as detonationsfähiges gas. However, no special measures to prevent dust formation are named. It is rather proposed to remove formed dust by blowing or blowing largely.

In DE 102 31 345 In addition to a device for producing plastic containers by stretch blow molding, a device for coating the inner walls of a blow-molded plastic container is described. This has in a manifold block a mixing chamber, open into the fluid lines for the gases and liquid used and in turn is in communication with the interior of a blow-molded plastic container. The fluid line for the liquid opens via a nebulizer into the mixing chamber such that the fluid arrives in an atomized form and mixed with the fuel gas inside the plastic container, where it is ignited by a arranged in the mixing chamber or in a stretching die ignition device.

Also if the device makes any progress in the delivery of the Fluids must with Dust formation in the course of combustion can be counted as no activities against premature reaction in the gas phase.

The The present invention therefore has the object, a method and a To provide apparatus for the production of blow-molded hollow plastic bodies, which consists of a means of combustion of a fuel gas mixture from a combustible gas, for example hydrogen, and an oxidizing gas Gas, for example. Air produced, essentially of silicon oxide existing, barrier layer are provided, with dust formation as Competition reaction avoided to form the diffusion barrier layer and one possible effective diffusion barrier layer against diffusion of gases and steaming is reached.

According to the invention the object is achieved in a first embodiment, characterized in that for producing the diffusion barrier at least one gaseous or vaporous chemical starting compound or mixture of such compounds (hereinafter referred to as Schichtbildnersubstanz) injected into the preform or the intermediate molded or the final molded plastic hollow body and after the preforming by igniting a likewise injected Brenn gas mixture is converted to a barrier layer on the inside of the hollow plastic body, wherein the combustion is conducted so that the molecules of the Schichtbildnersubstanz converted by them reach the wall of the plastic hollow body by the shortest possible route and while avoiding concentration enrichments. According to the invention, it is therefore avoided that a flame front proceeding from the ignition location covers an unnecessarily long distance during combustion through the intermediate or final molded hollow body. This would be the case, for example, if in an elongated plastic hollow body the ignition would occur exclusively in the middle, near one end (typically opening or bottom) of the hollow plastic body or even in a gas space communicating with the opening outside the hollow plastic body.

According to the invention, the ignition of the fuel gas mixture takes place at at least two locations within the intermediate or final molded hollow plastic body, which are arranged so that the flame fronts emanating from them reach the surrounding wall of the plastic hollow body in approximately the shortest path. This will be explained below with reference to 1 to 5 exemplified. They show in detail:

1 a longitudinal section through an inventive device for coating a longitudinally shaped plastic hollow body within a stretch blow mold,

2 a cross section thereto along the radius length 4 .

3 a longitudinal section through an apparatus for coating a compact plastic hollow body within a Steckblasform

4 a longitudinal section through an apparatus for coating a hollow plastic body of compressed shape within an extrusion blow mold and

5 a device similar 1 , Wherein the design of the ignition device with piezo ignition is shown schematically.

Example 1:

In the case of oblong shaped, rotationally symmetrical plastic hollow body, as in 1 shown, the ignition takes place simultaneously at several locations along the longitudinal axis within the plastic hollow body 1 , In blow molding machines, the ignition device is advantageously in the drawbar 3 integrated and the places of ignition (hereinafter as ignition points 2 . 2 ' . 21 and 22 referred to) along the inside of the mold located length of the drawbar 3 distributed, being from the opening 11 the plastic hollow body farthest ignition point 22 about a radius length 4 located away from the surrounding walls of the plastic hollow body. In the case of extrusion-blown hollow bodies in which a stretch rod is not intended by definition, a blow pin used for inflation is preferably designed in such a way that it receives the ignition device as described above. In general, this means an extension of the mandrel such that the end is at most about a radius length of the plastic hollow body removed from the ground.

If the blown and to be coated plastic hollow body no essentially circular Having a cross-section, under radius length, the means of the largest and the smallest, half cross-section be understood.

In the case of a currently customary, essentially rotationally symmetrical beverage bottle, the ignition point is located 22 So on the longitudinal axis and by a radius length from the bottom of the bottle 12 away. The further ignition points 2 . 2 ' are distributed at substantially the same distance over the stretching rod, wherein the opening closest to the ignition point 21 from this again about a radius length 41 is arranged remotely. In this case, the ignition points preferably have a distance of approximately one radius length of the plastic hollow body or less. The flame front common to the ignition points can be approximated as a superposition of the approximately spherical individual flame fronts emanating from the individual ignition points (in FIG 1 as dashed circles 5 be represented).

This applies to the case that the structure of the ignition device at the respective ignition point is designed so that starting from this ignition point can form over the circumference of the extension rod or mandrel approximately evenly distributed, radially propagating flame front. If this is not the case and has the ignition at the individual ignition points a pronounced directional characteristic as in 2 represented by a cross section through the plastic hollow body (eg. Within a solid angle of 120 °), so are several, in this example 3 ignition points 2 . 2 ' ... distributed over the circumference of the drawbar (in this example offset by 120 °).

Example 2:

In case of compact plastic hollow body (s. 3 ), of which here are those with a length about the same size as the cross-section are understood to be that of the opening 101 farthest point of ignition 22 less than a radius length 4 , preferably about a half radius length 2.4 or less from the ground 102 of the plastic hollow body 10 away. The distance between the ignition points 2 one another is chosen smaller than a radius length, preferably about half the radius length. The ignition point 21 , which is closest to the opening, is also provided less than a radius length, preferably about one-half radius length away from it.

Example 3:

In particular, in the case of extrusion-blown hollow plastic body, these can also have a compressed shape, ie that the imaginary by an opening longitudinal axis can be significantly shorter than the diameter. This is given for example in very wide-mouthed packaging containers. In this case (s. 4 ) is provided according to the invention, a plurality, eg. 4 , of igniters 300 inside the end-molded plastic hollow body 100 spread radially with a device, not shown, so that they are approximately in the middle of its length 400 to come to rest. The distance between the ignition points 22 at the end of each igniter to the wall of the plastic hollow body and the individual ignition points to each other is less than half the length 400 , preferably about one quarter of the length 400 ,

According to the invention the ignition of the fuel gas for the final shaping of the bottle or for the production of Each layer by means of a sufficiently hot body, eg. A filament, or an electrically generated arc ("spark") by applying a suitable high voltage (hereinafter referred to as ignition voltage referred to) according to the prior art or preferably by Compressive loading of one or, more preferably, a plurality of piezocrystals.

For example, as in 5 illustrated by a longitudinal section, in particular for flame-assisted blowing or coating bottles made of PET piezocrystals 6 . 6 ' ... at the ignition points 2 . 2 ' . 21 and 22 entlag a stretch rod such between pressure pieces 7 . 7 ' .. inside the hollow stretch rod 3 arranged that they are crushed simultaneously by a device, not shown. Once a sufficiently high external force in the axial direction (shown as arrow 8th ) acts on the piezoelectric crystals, the piezoelectric crystals are pressed together in the same way and thus induces a voltage across the piezocrystal, which discharges when exceeding the breakdown voltage for the present gas mixture over at least two not shown, associated with the piezoelectric crystals electrodes as an arc , Through recesses in the shell of the stretch rod at the ignition points 2 . 2 ' . 21 and 22 The arcs generated in this way cause the ignition of the gas mixture within the preform or the intermediate or final molded plastic hollow body.

According to the invention, the pressure pieces 7 . 7 ' ... and the piezocrostrap 6 . 6 ' ... Also be arranged on the outside of the stretch rod, whereby no recesses in the extension rod are required.

Especially the advantage is that at Generation of ignition voltage no high-voltage cables required by means of piezo crystals are because the voltage is generated directly at the ignition points. hereby be problems with the high voltage guide within the frequently and quickly moving drawbar avoided. Also, this arrangement is insensitive across from condensed water, which is produced as a reaction product during combustion. The ignition at the different ignition points becomes reliable synchronized, which also helps prevent dust formation Advantage is.

in the Case of a blower with curve-controlled mechanical functions, as is usual with today's stretch blow molders for high throughput, can the force required to squeeze the piezocrystals with advantage over a transmitted cam-controlled lever mechanism on the plungers become.

in this connection the force acting on the piezocrystals is continuously built up. But it is also possible over the controlling curve potential energy, for example by tensioning a spring or lifting a hammer build up and at the time of ignition, also over the curve is controlled on the plungers by triggering the Feather or hitting piece to let act.

According to the invention, the method for coating plastic hollow bodies is carried out as follows:
A sufficiently heated preform made of plastic or an immediately prior extruded plastic tube is placed in a forming tool whose inner contour corresponds to the outer contour of the hollow plastic body to be produced, and closed the forming tool. Depending on the type of blow molding process for molding the hollow plastic body, various embodiments of the method according to the invention are used.

Stretch blow molding:

In the case of a rigid plastic such as PET, the preform has become the prior art produced by injection molding and usually shortly before being transported into the forming tool by means of a radiant heater to a temperature of about 370 K. Subsequently, the preform according to the prior art within the mold by blowing a gas or gas mixture is pre-blown at a pressure of 2 to 15 bar and thereby stretched under axial movement of the draw bar. As a result, one of the later form of the plastic hollow body is substantially similar, but not yet fully formed intermediate molding produced. The final shape of the plastic body, as generally known in the now following final forms under a pressure increase to 25 to 50 bar, which is achieved either by blowing a gas under this pressure or preferably by igniting a fuel gas mixture. The fuel gas mixture is preferably equal to the gas or gas mixture which was previously used for pre-blowing. Alternatively, as also previously known, but also with another gas or gas mixture, eg. Pre-blown air then the fuel gas, bespw. Hydrogen, blown and the fuel gas mixture thus prepared are ignited.

If the fuel gas mixture previously at least one gas or vapor-forming Schichtbildnersubstanz in sufficient Quantity was added, this is already the diffusion barrier layer educated.

Otherwise is inventively as a variant the pressure, as just described, degraded and a fresh fuel gas mixture blown together with at least one Schichtbildnersubstanz and ignited to form the diffusion barrier layer. These Variant is preferably used in larger plastic hollow bodies because here despite the use of the device under certain circumstances the Formation of dust is not excluded with the necessary security can be. In this case it is to avoid too high concentrations on reactive particles advantageous, the pressure before blowing the Schichtbildnersubstanz and the fuel gas as much as possible, preferably except for one atmosphere, reduce

Extrusion blow:

in the In the case of a less rigid plastic such as PEHD, the preform is made out of one piece freshly extruded plastic tubing, which varies according to the state the technique with sufficient residual heat from a ring-shaped slot under the influence of gravity Lowering vertically downwards and separating from the forming tool the hose is enclosed. Subsequently, the plastic tube by blowing in a gas or gas mixture, preferably air, inflated with a pressure of 2 to 15 bar to the final shape of the plastic hollow body. According to the invention then the Pressure by opening a drain valve to a maximum value of 5 bar, but preferably atmospheric pressure reduced. Subsequently be a fuel gas mixture and Schichtbildnersubstanz or Schichtbildnersubstanzen blown and ignited by means of the ignition device according to the invention. hereby the diffusion barrier layer is formed.

It In any case, it should be noted that prior to the preparation of the diffusion barrier layer must be secured that yourself no drop-shaped condensed water is inside the plastic hollow body, otherwise no dense diffusion barrier layer can form. Such condensed water may in particular as a result of previous combustion of fuel gas and must then be removed become. According to the invention for this purpose a dry, preferably heated, Gas or gas mixture, eg. Air, with an overpressure of up to 15 bar injected briefly and immediately afterwards left out.

It is essential to the invention that the Ignite the reaction of the laminating substance or substances to the diffusion barrier layer the ignition device described in this document is used.

For this Processes are advantageously used as layer-forming substances compounds used with a low tendency to dust. It became surprising found that yourself reactive, but oxygen-free silicon compounds in this regard particularly suitable as Schichtbildnersubstanzen. Examples are silazanes, (especially hexamethyldisilazane, tetamethyldisilazane and hexamethylcyclotrisilazane) and disilanes, for example 1,2-bis (diisopropylamino) disilane.

in the The following is the invention using the example of a Verfahrensabufs explains:

Example 4:

A blow-molding machine for elongated PET bottles with a volume of 0.3 dm ³ corresponding 1 is with a gas supply system for compressed air, fuel gas and Schichtbildnersubstanz, a high-voltage ignition device in an adjacent from the outside of the bottle opening manifold block and integrated in the drawbar piezo ignition corresponding 5 equipped. After introducing a preform preheated to 380 K, the mold is closed and the parison is inflated by blowing compressed air at a pressure of 12 bar to the intermediate-formed bottle. Subsequently, while maintaining the pressure within the intermediate shape th bottle additionally blown hydrogen as a fuel gas with a partial pressure of about 1 bar and brought the fuel gas mixture thus prepared using the high voltage ignition device to the explosion. Due to the resulting pressure surge, the wall of the intermediate-shaped bottle is completely pressed against the inner contour of the mold and the bottle is finally shaped. After 400 ms, the pressure inside the bottle is reduced to the ambient pressure of and then immediately blown dry, preheated to 300 K air at a pressure of 10 bar. Immediately after reaching this pressure, the now mixed with water vapor is released again and blown again after reaching the ambient pressure, a mixture of 30 cm ^{3 of} hydrogen and 5 cm ^{3 of} vaporous hexamethyldisilazane. The thus prepared new fuel gas mixture is brought without further delay by the piezo ignition device to the explosion and in this case the diffusion barrier layer produced on the inner wall of the bottle. The bottle is left to cool for 500 ms under pressure in the mold and then removed after releasing the pressure.

The Object is according to the invention in another embodiment solved, by first a precursor layer consisting of the laminating substance on the inside the preform or the intermediate or final molded plastic hollow body applied and by combustion of an internal fuel gas mixture is converted to the diffusion barrier layer. This allows the Formation of dust can be safely avoided. For this purpose, the laminating substances according to the invention so selected that the from this first formed precursor layer under the influence of the combustion particularly easily in a defect-free Diffusion barrier layer can be converted. Another one The criterion is that the Schichtbildnersubstanzen one enough low volatility not to under the process-related temperatures the surface evaporate the plastic material before entering a diffusion barrier layer Can be converted. This would not only reduces their layer thickness, but it also exists the danger that the from the surface discharged vapor of the laminating substance or substances below Action of combustion in the gas phase to dust reacts, causing would lead to a poor quality diffusion barrier layer. So is the temperature of a preform made of PET after heating in a stretch blow molder between 370 and 390 k. The temperature the final molded plastic hollow body decreases with the duration of the wall contact within the mold down to a value of about 300 K. It is for the selection of the laminating substance So considerably, at which time of the blowing process on the precursor layer is brought. It has been found that laminating substances with a vapor pressure of less than 5000 Pa, preferably 2000 Pa at the respective temperature of the plastic material for this embodiment of the invention are particularly suitable.

to Coating stretch blown hollow plastic body is the selected Schichtbildnersubstanz to form the precursor layer according to the prior art with a Naßauftragstechnik on the inside the preform or the intermediate or final molded plastic hollow body complete Covering the surface applied. Outside of the mold Can as a wet application technique spraying, preferably flood, dive or spin-on can be selected. Inside the mold may be the precursor layer by spraying on the inside of the preform or the intermediate or final molded Plastic hollow body through spray on or by condensing on the inside of the final molded hollow plastic body become. In this case, preference is given to the layer-forming substance of the substances with as possible low proportion of solvents or diluents, particularly preferred without solvent or diluent.

alternative become at room temperature solid Schichtbildnersubstanzen as melt or pasty Stratifying agents already in the production of preforms by injection molding Coinjection applied to the inside.

at Extrusion blown plastic hollow bodies is the order of precursor layer carried out within the mold analogous to the stretch blown, wherein the introduced into the mold Plastic tube corresponds to the preform. To be favoured according to the invention, however Room temperature solid Schichtbildnersubstanzen as a melt or but pasty Schichtbildnersubstanzen together with the plastic tube and on the inside coextruded and then introduced into the mold.

A Another preferred variant is that at room temperature liquid Schichtbildnersubstanzen according to the invention immediately after its extrusion onto the inside of the plastic tube be applied. Apply by spraying or Flooding, but preferably by stripping the liquid Schichtbildnersubstanzen from a circular Carrier, which enclosed grazing by the extruded plastic tube is and the Schichtbildnersubstanzen via suitable means, eg. a felt or a lip on the passing plastic hose as a closed, thin Precursor layer transfers.

The Thickness of the precursor layer is calculated so that the resulting diffusion barrier layer has a thickness of not below 10 nm, preferably not less than 20 nm, and not more than 1000 nm, preferably not over 200 nm. Becomes the precursor layer So introduced into a final molded plastic hollow body, is in the Measuring only the relatively small volume change in their conversion into the diffusion barrier layer. A precursor layer, which is introduced into a preform, however, must by about the draw ratio of his surface through the blowing process (area of the Plastic hollow body divided by the area the inside of the preform), so be made significantly thicker.

• a) Kohlenstoff in nur geringem Maße enthalten, d.h. in einem Verhältnis zum Silizium von kleiner oder gleich 2 (C/Si ≤ 2) und
• b) Sauerstoff in einem Verhältnis zu Silizium von größer oder gleich 0,5, bevorzugt größer oder gleich 1 (O/Si ≥ 0,5; bevorzugt O/Si ≥ 1) oder
• c) Stickstoff in einem Verhältnis zu Silizium von größer oder gleich 0,5, bevorzugt größer oder gleich 0,75 (N/Si ≥ 0,5; bevorzugt N/Si ≥ 0,75) enthalten.

In the context of this embodiment, silanes, siloxanes and silazanes having a sufficiently high boiling point are in principle suitable as laminating substances in the context of this embodiment. It has been found that in the sense of a slight chemical conversion to a dense, defect-free diffusion barrier layer from the circle of these laminating substances such are particularly suitable, the

• a) contain carbon in only a small amount, ie in a ratio to the silicon of less than or equal to 2 (C / Si ≤ 2) and
• b) oxygen in a ratio to silicon of greater than or equal to 0.5, preferably greater than or equal to 1 (O / Si ≥ 0.5, preferably O / Si ≥ 1) or
• c) nitrogen in a ratio to silicon of greater than or equal to 0.5, preferably greater than or equal to 0.75 (N / Si ≥ 0.5, preferably N / Si ≥ 0.75).

Unsuitable according to the invention are compounds that in their transformation into a solid and dense Layer form vapor-permeable pores or due to strong Shrinkage tend to crack.

For example, 1,3,5,7-tetramethyltetrasiloxane is particularly suitable for a wet application technique at low temperature of the plastic material, and hexamethylcyclotrisilazane for higher temperatures. For even higher temperatures corresponding compounds with higher Molekutargewicht and low vapor pressure are used, in particular, homologues of the above Schichtbildnersubstanzen, for example, polysilazanes of the formula -. [SiR ₂ NH] _x - or - [SiR ₂ -NR] _y -, or copolymers thereof, where R is preferably a hydrogen atom or a methyl group, or silsequisiloxanes, for example poly (methylsilsequisiloxane). If these laminating substances are solids with excessively low ductility at the desired application temperature, it is intended to convert these into liquid or pasty form by mixing with suitable solvents. Solvents which are themselves suitable layer-forming substances are preferred. If it is necessary to increase the rate of the reaction to the diffusion barrier layer, it is provided to add suitable catalysts to the laminating substance before the formation of the precursor layer.

to Modification of the properties of the diffusion barrier layer, eg. toughness, According to the invention the Schichtbildnersubstanz Organoaluminum compounds, preferably aluminum alkoxides added.

Example 5:

For coating extrusion blown fuel cans made of PEHD with a diffusion barrier layer against fuel components, a conventional Coxtrusionsblasmaschine was equipped with a gas supply system for compressed air and fuel gas and a Hochspannungszündeinrichtung in an externally adjacent to the bottle opening distribution block. According to the invention, a precursor layer of poly (methyl silsesquisiloxane) with 0.5% portion of a conventional catalyst is extruded to the implementation of the method on the inside of the extruded PEHD tube, such that the layer thickness does not exceed 5 microns. The internally coated tube is inserted into the mold and compressed air is blown at 9 bar into the shape of a fuel canister. Here, the precursor layer is stretched to a thickness of about 500 nm. After a cooling time of 10 s, the compressed air is released and atmospheric pressure is restored. Subsequently, 400 cm ^{3 of} hydrogen are injected as fuel gas and ignited the resulting fuel gas mixture with the high voltage ignition device. As a result, the precursor layer is converted into a diffusion barrier layer. After a further cooling time of 5 s, the internally coated plastic canister is removed from the mold.

Can be produced according to the invention are provided with a diffusion barrier layer plastic hollow body preferably formed by the stretch blow molding packaging container for drinks, pasty and solid Food, cosmetics, pharmaceuticals and chemicals of all kinds and extrusion blow molded packaging containers for the same Fields of application, furthermore technical containers plastic fuel tanks as well as lines, eg. Bellows made of plastic.

1

Plastic hollow body, elongated

11

Opening to 1

12

Ground too 1

2, 2 '...

ignition points

21

ignition point closest to the opening

22

ignition point with the greatest distance to the opening

3

stretching rod with integrated ignition device

4

radius length

2.4

half radius length

41

Radius length in the range the opening

5, 5 '...

from ignition point outgoing flame front

6 6 '...

piezo crystal

7, 7 '...

Pressure piece

8th

direction of force

10

Plastic hollow body, compact

101

Opening to 10

102

Ground too 10

100

Plastic hollow body with compressed form

300

detonator

400

length

Claims (19)

Process for the preparation of an inside coated Plastic hollow body by stretch or extrusion blow molding, wherein a preheated preform introduced into a mold and by means of a pressurized gas to an intermediate molded Plastic hollow body expanded and by ignition a blown fuel gas mixture to form a further increased pressure to its final shape is formed and one Fuel gas mixture with the addition of a Schichtbildnersubstanz or more Schichtbildnersubstanzen in the intermediately formed or the final molded Plastic hollow body blown and ignited becomes like that that the layering reaction products the surrounding walls of the intermediate or final molded plastic hollow body on the shortest Achieve ways and thereby to form a diffusion barrier layer capable be, where before blowing the fuel gas mixture under Addition of the laminating substance or the laminating substances the pressure within the intermediate molded plastic container preferably is reduced to ambient pressure. Method according to claim 1, characterized in that that before the injection of the fuel gas mixture with the addition of the Schichtbildnersubstanz or the laminating substances the pressure within the intermediately formed Plastic container reduced to ambient pressure and a dry gas under pressure blown in and then is drained again. Process for the preparation of an inside coated Plastic hollow body by stretch or extrusion blow molding, wherein a preheated preform introduced into a mold and by means of a pressurized gas to an intermediate molded Plastic hollow body expanded and by ignition a blown fuel gas mixture to form a further increased pressure to its final shape is formed and one Fuel gas mixture with the addition of a Schichtbildnersubstanz or more Schichtbildnersubstanzen in the intermediately formed or the final molded Plastic hollow body blown and ignited becomes like that that the layering reaction products the surrounding walls of the intermediate or final molded plastic hollow body on the shortest Achieve ways and thereby to form a diffusion barrier layer capable be, where as Schichtbildnersubstanz one or more oxygen-free Silicon compounds are used. Method according to claim 3, characterized that as Schichtbildnersubstanzen preferably oxygen-free silicon-nitrogen compounds be used. Process according to Claims 3 and 4, characterized that the Schichtbildnersubstanzen particularly preferred from the group of Silazane and nitrogen-containing disilanes can be selected. Device for producing an internally coated plastic hollow body ( 1 . 10 , or 100 ) by means of stretch or extrusion blow molding by ignition of a fuel gas mixture with the addition of one or more Schichtbildnersubstanzen with at least one in each case in the preform, the intermediate or final shaped hollow plastic body protruding ignition device and at least a total of two ignition points ( 2 . 2 ' ..., 21 and 22 ), at which the ignition takes place, whereby the distribution of the ignition points ( 2 . 2 ' ..., 21 and 22 ) over the length of the igniter depending on the proportions of the hollow plastic body ( 1 . 10 or 100 ) provided and the individual ignition points from each other and from the next wall of the plastic hollow body maximum about a radius length ( 4 . 41 ), preferably less than a radius length ( 4 . 41 ) are spaced Apparatus according to claim 6, characterized in that in the case of compact plastic hollow body ( 10 ) the individual ignition points ( 2 . 2 ' ..., 21 and 22 ) of each other and of the next wall of the plastic hollow body less than a radius length ( 4 ), preferably a half radius length ( 4 / 2 ), are spaced Apparatus according to claim 7, characterized in that in the case of upset plastic hollow body ( 100 ) several ignition devices ( 300 ) are distributed over the cross-section and the individual ignition points ( 2 . 2 ' ..., 21 and 22 ) from each other the and the next wall of the plastic hollow body ( 100 ) by a maximum of half the length ( 400 ) are spaced. Apparatus according to claim 6, characterized in that the ignition device in the drawbar ( 3 ) is integrated a stretch blow molding Device according to claim 6, characterized in that that the detonator is integrated into the blow pin of an extrusion blow molding machine. Apparatus according to claim 6 and 7 or 8, characterized in that the ignition per ignition point ( 2 . 2 ' ..., 21 and 22 ) by an arc between two electrodes after applying a high voltage from the outside. Apparatus according to claim 6 and 7 or 8, characterized in that the ignition per ignition location is effected by an arc between two electrodes, wherein the high voltage thereto by applying a pressure to a piezoelectric crystal ( 6 ) is produced. Apparatus according to claim 6 and 7 or 8, and 12 characterized in that the ignition on the piezoelectric crystal ( 6 ) exerted pressure mechanically over a revolving curve, a cam disc or - wave or an eccentric is triggered. Process for the preparation of an inside coated Plastic hollow body by stretch or extrusion blow molding, wherein first one consisting of one or more Schichtbildnersubstanzen precursor layer in liquid or pastier Mold or in the form of a melt on the inside of the preform or between-or finally molded plastic hollow body upset and by combustion of an internal fuel gas mixture is converted to the diffusion barrier layer and as Schichtbildnersubstanz or Schichtbildnersubstanzen silicon compounds are used, the easily and without the formation of defects such as pores or cracks can be converted into the diffusion barrier layer when Laminating substances are used silicon compounds, which contain carbon to a low degree, i. in one relationship to the silicon of less than or equal to 2 (C / Si ≤ 2) and oxygen in a ratio to Silicon of greater or greater equal to 0.5, preferably greater or equal to 1 (O / Si ≥ 0.5; preferably O / Si ≥ 1) or nitrogen in a ratio to Silicon of greater or greater equal to 0.5, preferably greater or 0.75 (N / Si ≥ 0.5; preferably N / Si ≥ 0.75) contain. Method according to claim 14, characterized in that that the used as Schichtbildnersubstanzen silicon compounds for Improvement of the coating properties Aluminum compounds, preferred Aluminum alkoxides are added. Process according to claims 14 and 15, characterized that the Schichtbildnersubstanzen selected be that you Vapor pressure at the respective wall temperature of the preform, the intermediate or finally shaped Plastic hollow body, on which they are applied, a value of 5000 Pa, preferably 2000 Pa, does not exceed. Process according to claims 14, 15 and 16, characterized characterized in that precursor layer in the case of the stretch blow molded plastic hollow body outside the mold by flooding, dipping or spin on the Is applied inside the preform. Process according to claims 14, 15 and 16, characterized characterized in that precursor layer in case of extruded blown plastic hollow body outside of the mold is applied by at room temperature one or several liquid ones Schichtbildnersubstanzen immediately after its extrusion on the inside of the Plastic hose by spraying or flooding, but preferably applied by stripping from a circular support be surrounded by the extruded plastic tube grazing becomes. Process according to claims 14, 15 and 16, characterized characterized in that precursor layer in case of extruded blown plastic hollow body outside of the mold is applied by solid at room temperature Schichtbildnersubstanzen as a melt or pasty Schichtbildnersubstanzen together with the plastic tube and be coextruded on the inside.