WO2011134966A1 - Device for producing a filler-containing spray jet - Google Patents

Abstract

The invention relates to a device for producing a filler-containing spray jet in order to produce layers and/or molded parts from a reactive resin by spraying. The fillers are wetted uniformly with the resin in a device according to the invention.

Description

 BMS 105001 - Foreign countries

Apparatus for producing a filler-containing spray jet

The present invention relates to a device for producing a filler-containing spray jet for producing layers and / or moldings from a reactive resin in the weft operation.

The use of different reactive resins for the production of moldings is well known in the art. When it comes to applying a reactive resin to a substrate, spraying has usually prevailed as a coating technique. As reactive resins, polyurethanes are often used. In addition, however, other two- or multi-component systems such as epoxy resins or (meth) acrylic-based resins are also used.

Usually, the mixing of the liquid reactive components takes place in a mixing head, wherein basically between high pressure (HD) and low pressure (LP) mixture can be distinguished. In the low-pressure process, the components are mixed in a pressure range up to 40 bar. By synchronously opening valves, the reactive components are released in the desired ratio in the mixing chamber. In this mixing then takes place by stirring, for example with an intensive mixer, or static mixer instead.

In high-pressure machines, the reactive components circulate in a pressure range up to 250 bar. Upon initiation of a shot, the individual reactive components meet with the corresponding high pressure in the mixing chamber and thereby mix. The spray application is realized both in the HD and in the ND process via downstream atomizer systems.

For many applications it is necessary to add additional components to the reactive resin. Depending on the end product, this could be fire retardants, aging inhibitors or UV protectants, which impart the required properties to the molded part or the layer of the reactive resin. Furthermore, it is also possible to mix fibers which increase the stability of the product obtained. The admixture of solid, liquid and / or gaseous components in the reactive mixture has been realized in different ways in the prior art. Frequently, the additives are dispersed or dissolved in one of the reactive components used for the resin. One possibility is to mix the additives to be used with one of the two reactive components and to use the mixture thus obtained to prepare the resin.

In DE 3909017 Cl and DE 4010752 Al, for example, the production of expanded graphite or expandable graphite / melamine-containing

Flexible polyurethane foams described. The additives used herein are dispersed in the polyol component of the polyurethane. The problem here is that the additives are not soluble in the corresponding component. The dispersion must therefore be stirred constantly to avoid sedimentation of the solid in the reservoir. In the case of melamine in a Polyoldispersion also shows that after sedimentation, the melamine cakes quickly, which makes redispersing much harder, sometimes even impossible.

When additives are dispersed in the polyol component of the polyurethane, components from the polyol formulation can adsorb to the surface of the added solids. In the sedimentation of solids, these components are finally removed from the polyol formulation. In particular, if the redispersion of the sediment is difficult, this leads to deviations in the polyol composition and thus to new properties of the polyurethane resin to be produced. For example, the curing time of the resin is changed thereby.

Even solids with different specific gravity (based on the carrier liquid) can be processed so poorly. Hollow glass spheres may, for example, float in the reactive component, swelling in the case of wood flour.

In addition, if necessary, the physical properties, for example the viscosity, of the corresponding liquid reactive component are also changed by the presence of an additive, as a result of which the miscibility of the reactive components is usually adversely affected. In addition, when processing solid additives in the corresponding liquid reactive components via HD or LP equipment, shear forces act on the additives. As a result, they are crushed, which can change their effect in the resin uncontrolled. Sometimes chemical side reactions of the additives with the reactive components can not be excluded.

An alternative to the production of filler-containing layers or moldings from a reactive resin is the injection process, in which a filler-containing gas stream is passed into a stream of the reactive components.

The mixing of reactive components with a filler component can be done outside the mixing head. This is known, for example, from DE 2517864 A1, US Pat. No. 3,302,891, WO 2009/052990 A1 or EP 1 458494 B1. Here, the mixing of a spray of Reaktivkunststoffes with a spray of the corresponding filler. In the context of the present invention, a spray jet is also understood to mean a jet which consists essentially of fine particles (droplets) of a reactive mixture dispersed in a gas stream, ie a mixture of at least two reactive components.

If fillers and reactive mixture are mixed downstream of the mixing chamber, the wetting of the filler with the resin is often incomplete.

From WO 2009/143979 Al a method is known in which the gas stream containing solids is not introduced into the already dispersed spray jet of the reaction mixture, but in the still liquid non-dispersed jet of the reaction mixture. About a mixing head downstream header with an integrated mixing level, the gas-solid mixture is fed to the liquid non-dispersed reaction mixture, mixed by means of the resulting Rotationsdralls and then discharged as a multi-phase mixture via a sprayer as a spray. When processing higher solids contents, however, the wetting of the particles may also be incomplete here. High solids contents with small particle sizes provide the reaction mixture with a large surface area which, due to the short residence time in the mixing zone, can not be sufficiently mixed and wetted with the reaction mixture. In addition, solid particles of high specific gravity concentrate on the wall region of the flow channel due to centrifugal forces and can only be mixed to a limited extent with the reaction mixture due to the compression.

DE 10 2007 016785 A1 relates to a method and a device for producing molded parts, comprising a layer of polyurethane in the weft operation, in which a gas stream is introduced into the flow channel of the spraying device at at least two positions. DE 4417596 A1 describes a method for producing a mixture consisting of reactive plastic components and fillers. Here, the plastic components are mixed under high pressure in a mixing chamber and get out of this as a plastic component mixture in a arranged at an angle to the mixing chamber outlet pipe, in which the fillers are registered and wetted intensively with the plastic component mixture. The inlet opening for the solid in the flow channel faces the inlet opening for the plastic mixture. Here, however, only fine-grained and free-flowing solids can be processed, which do not tend to clump.

EP 0771 259 B1 comprises a device for the production of plastic parts penetrated with long reinforcing fibers. Here a wetting of the solid and liquid components takes place at the discharge itself, but it is not a spray.

The object of the present invention is therefore to provide a device for the production of layers and / or moldings from a reactive resin in the weft operation, with which different fillers in a high proportion based on the amount of reactive resin in both high pressure (HD) - and in the Low pressure (ND) method can be sprayed processed. In this case, a uniform wetting of the filler (s) and also a homogeneous distribution of the filler (s) in the final product must be ensured. Another object of the present invention is that the self-cleaning of a flow channel containing at least filler and transport gas is ensured.

The object underlying the present invention is achieved by a device for producing a filler-containing resin spray, which is characterized in that it a. a cylindrical filling substance ka na I 6 with at least one inlet 1 for introducing a mixture of transport gas and filler and an axially movable ejector 8 therein,

 b. a cylindrical flow channel 9 for introducing filler from the Fül Istoff ka na I 6 and

 c. a cylindrical mixing chamber 5 having at least two inlet openings 4 for the metered addition of at least two reactive components,

wherein the mixing chamber 5 and the Fül Istoff ka na I 6 include an angle which is not equal to 180 °, while the Fül Istoff channel 6 and the flow channel 9 form an angle of 180 °.

According to the invention, the mixing chamber 5 can be an HD or an LP mixing chamber, for example a static mixer. If the mixing chamber 5 is an HD mixing chamber, the device according to the invention furthermore has an ejector 2 for mechanical cleaning of the mixing chamber 5. A corresponding device schematically shows Fig.1.

An apparatus according to the invention makes it possible to carry out a method for producing a corresponding filler-containing resin spray jet in which

 a. at least one filler and at least one transport gas are passed through at least one inlet 1 in the Fül Istoff channel 6 and the filler-gas mixture from the Fül Istoff channel 6 is passed into the flow channel 9,

b. at least two reactive components in the high pressure or low pressure are introduced and mixed with one another in the mixing chamber 5 via at least two inlet openings 4 and the reactive mixture thus produced is introduced into the flow of filler-gas mixture in the flow channel 9, c. the resulting, then filler-containing reactive gas mixture leaves the flow channel 9 via an outlet opening 7, d. then the mixing chamber 5 is cleaned and

 e. the Fül Istoff ka na I 6 and the flow channel 9 are mechanically cleaned by means of the ejector 8, in which this is moved to its cleaning position, in which the ejector 8 is guided in the flow channel 9.

In the H D method, step d of the method further comprises the mechanical cleaning of the mixing chamber 5 by means of the ejector 2.

In the H D method, the ejector 2 and the ejector 8 are moved from the firing position into their cleaning position one after the other for cleaning the device according to the invention. The firing position means that the ejector 2 is located in front of the at least two inlet openings 4 in the direction of the flow direction, so that these and the mixing chamber 5 are not covered by the ejector 2. The ejector 8 is located in the firing position in the direction of the flow direction in front of the at least one inlet 1. In mixing chamber 5, flow channel 9 and Fül Istoff ka na I 6 thus a transport and mixing of the components take place. The mixture can pass freely to the outlet opening 7 and the reactive resin filler mixture are discharged in the shot mode.

After firing, the ejector 2 and the ejector 8 are moved in the HD method to the ninth position. Here, the mixing chamber 5, filler channel 6 and flow channel 9 are mechanically cleaned, the mixing chamber 5 being cleaned by the ejector 2 and the filler channel 6 and the flow channel 9 by the ejector 8.

In the N D process, the mixing chamber 5 is cleaned in a manner known per se by a liquid cleaning agent and / or compressed air. The fuel Ia ka I 6 and the flow ngska n l 9 are also in the N D process by the Pusher 8 cleaned, as previously described in the HD method. The movement of the ejector 8 in its cleaning position takes place after the mixing chamber 5 has been cleaned.

While the prior art devices essentially use a gas stream or nozzle to atomize a reactive mixture and inject a further gas stream containing such solids into such an atomized spray, the apparatus of the present invention is characterized by having a solids containing gas stream over a filler ka na I 6 is introduced into a flow channel 9. In the transition region between the filler channel 6 and the flow channel 9, the reactive mixture is introduced from the mixing chamber 5 in this stream of filler and transport gas. This results in a mixing of at least one filler with the reactive mixture, whereby this (r) is wetted by the reactive mixture / are.

A reactive mixture is understood according to the invention to mean a mixture of at least two, in particular liquid, reactive components which are mixed with one another in the region of a mixing chamber in the HD or LP process. Such a reactive mixture is not in the form of finely dispersed reaction droplets, but is a liquid viscous jet.

According to the invention, one or more fillers in the filler channel 6 are transported with the aid of at least one transport gas. A filler is understood as meaning those substances which impart desired properties, such as mechanical stability or resistance to UV radiation, to the reactive resin layers or moldings to be produced. Corresponding fillers are well described in the prior art. The fillers may be used singly or in combination. According to the invention, the fillers may have the same or different physical properties, such as density, and / or the same or different physical properties have different geometric configuration. If a filler-containing reactive mixture is described below, this includes reactive mixtures which contain one or more fillers.

If the stream of reactive mixture and the filler-gas mixture meet, turbulence within the flow channel 9 occurs due to the different directions of flow, and thus thorough mixing of the filler (s) with the reactive mixture. In a device according to the invention, it is therefore also possible to process particularly high filler contents of up to 83% by weight, based on the composite. It is thus possible to process 100 g of filler, for example in the form of BaSO ₄ , with 20 g of reactive mixture.

Fig. 1 shows schematically a device according to the invention. Figs. 2a and 2b show an alternative embodiment.

In a device according to the invention, at least two reactive components are introduced into the mixing chamber 5 via the at least two inlet openings 4, in which the reactive mixture is formed from the corresponding reactive components. The reactive mixture is a reactive resin, for example a polyurethane, polyester or epoxy resin, in particular it is a polyurethane resin. If polyurethane resins and polyurethane reactive mixtures are described below, this also applies as a synonym for polyester and epoxy resin.

To prepare a polyurethane reactive mixture, at least one polyol is introduced via the at least two inlet openings 4 as a reactive component and at least one isocyanate is introduced into the mixing chamber 5 as a further reactive component. In this case, it is possible to use any polyols and isocyanates known from the prior art with which polyurethanes can be prepared. It is also possible according to the invention introduce different polyol and isocyanate components via the same or different inlet openings 4 in the mixing chamber 5.

The reactive components of any reactive resin are introduced into the mixing chamber 5 in the HD or ND process. Here is a thorough mixing of the individual reactive components. The reactive mixture thus produced is introduced into the flow from the filler-gas mixture into the flow channel 9.

Via the filler channel 6, a filler-gas mixture is passed into the flow channel 9. According fillings Iko ka na I 6 and flow channel 9 form an angle of 180 °. This allows the use of different types of fillers. For example, fibrous, platelet or spherical fillers can be processed and also those with a high abrasive effect. The filler (s) can / have, for example, a particle size of up to 2 mm, preferably up to 1 mm, particularly preferably up to 600 μm. They can be introduced into the filler channel 6 individually or in combination with the aid of the transport gas.

According to the invention, the filler is preferably fibers, for example glass fibers or mineral fibers, in particular wollastonite, through which the resulting product has improved mechanical stability. Further, as the filler, a flame retardant material may be used, such as expanded graphite, melamine or aluminum hydroxide. Fillers that have a high specific mass, such as BaS0 ₄ or magnetite, improve the acoustic properties. Defoaming can be achieved by the addition of molecular sieves for water, for example Baylith ^® powder. For an improved surface quality is the use of particularly fine-grained fillers, such as finely ground chalk. Also other well-known from the prior art fire retardants, UV protection agents or anti-aging agents can be introduced into the reactive mixture in a process according to the invention.

The transport gas for the fuel (s) is inert gas, air, nitrogen and / or carbon dioxide. In particular, air is used as a transport gas. In order to ensure an adequate transport of the filler (s), the transport gas flows with a volumetric flow rate of up to 700 nl / min, in particular with a volumetric flow rate of up to 500 nl / min into the exhaust I 6.

The degree of loading of the transport gas, defined as the mass of filler in kilograms per kilogram of transport gas, can be up to 30 kg of filler per 1 kg of transport gas, preferably up to 15 kg of filler per 1 kg of transport gas, more preferably up to 12 kg of filler per 1 kg of transport gas ,

In one possible embodiment, the device according to the invention further comprises at least one gas channel 3, preferably a plurality of gas channels 3, which open into the flow channel 9 in at least one plane. Via this at least one gas channel 3, a M ischgas is introduced into the flow channel 9. The liquid-reactive mixture and mixed gas meet one another in the flow channel 9. Due to their different flow directions, a further thorough mixing of the reactive mixture with the filler takes place.

In an apparatus according to the invention, the at least one gas channel 3 may be arranged in such a way that the flow direction of the gas flow of the mixed gas when entering the flow channel 9 is outside the center of the flow channel 9. As a result, the axial flow of the filler-containing reactive gas mixture is a radial flow in one direction (Rotationsrichtu ng) impressed. Are several gas channels 3 on different levels and they are arranged so that the flow direction of the gas stream of the mixed gas when entering the Flow channel 9 extends outside the center of the flow channel 9, this radial flow component preferably has in one plane in a rotational direction and in the following plane in the opposite direction of rotation.

Such a tangential arrangement of the at least one gas channel 3 leads to a turbulence of the filler-containing reactive mixture, whereby a homogeneous wetting of the filler (s) is ensured with the reactive mixture.

In addition to such a tangential arrangement, it is also possible according to the invention to arrange the at least one gas channel 3 axially in one plane. Here, the flow direction of the gas flow of the mixed gas when entering the flow channel 9 in the center of the flow channel 9th

According to the invention, it is possible both in a tangential and in an axial arrangement that several gas channels 3 are located on different planes. If there are at least two gas channels 3 on one level, they can be opposite one another on the level. The mixed gas can then be introduced into the flow channel 9 via the at least two gas channels 3 lying on the same plane such that the flow direction of the stream of the mixed gas passes into the flow channel 9 at the center of the flow channel 9. According to the invention, however, it is also possible that the inlet openings of the at least two gas channels 3 lying on the same plane are not opposite one another in the flow channel 9. The mixed gas can then be introduced into the flow channel 9 via the at least two gas channels 3 lying on the same plane such that the flow direction of the flow of the mixed gas, when entering the flow channel 9, is outside the center of the flow channel 9. According to the invention, the at least one gas channel 3 and the flow channel 9 form an angle in the range of 0 to 180 °. Depending on the type and amount of filler (s) used / used, the choice of the angle can be used to optimize the mixing between the filler and the reactive mixture.

Via the at least one gas channel 3, a mixed gas can be introduced into the flow channel 9. Inertgas, air, nitrogen and / or carbon dioxide are used as mixed gas, in particular air is used as mixed gas.

In a device according to the invention, the mixing chamber 5 and the filler channel 6 and the flow channel 9 are cleaned after firing in the case of the HD process by the ejector 2 and the ejector 8 or ND process by the ejector 8. During the mixing of the reactive components with one another or the mixing of the reactive mixture with the solid-gas mixture, the ejector 2 and the ejector 8 are in the firing position.

After firing the ejector 2 is moved in cleaning position in the HD process. As a result, the mixing chamber 5 is mechanically cleaned. According to the invention, the length of the ejector 2 corresponds to the length of the mixing chamber 5 as far as the inlet into the flow channel 9, so that in the cleaning position the ejector 2 completely cleans the mixing chamber 5, but does not reach into the filler channel 6 or the flow channel 9. In order to allow a good cleaning of Fül Istoff ka na I 6 and flow channel 9, the abutting surface of the ejector 2 is concave. In particular, it is provided with such a curvature that corresponds to the cylindrical shape of the flow channel 9.

During the mixing of the reactive components with each other or the reactive mixture with the solid-gas mixture is also the Pusher 8 in firing position. After firing the ejector 8 is brought into the cleaning position in the HD process after the ejector 2, in the N D-process after cleaning the mixing chamber 5, wherein the ejector 8 is at least as long as the filler chamber 6 and the flow channel 9 up to the outlet opening. 7

In a further embodiment of the device according to the invention, the ejector 8 comprises a sleeve 11 and a core 10 movable therein, wherein the sleeve 11 has at least one opening in the firing position at the level of the at least one inlet 1, through which the filler gas Mixture in the Fül Istoff ka na I 6 is introduced and ends in the direction of flow before the mouth of the mixing chamber 5 in the flow channel 9, and the core 10 ends in the firing position in the direction of flow above the at least one inlet 1.

In this way, the mixing chamber 5, Fül Istoff ka na I 6 and flow channel 9 of different inner diameters, in particular, the inner diameter of the Fü 11 substance ka na Is 6 is smaller than the inner diameter of the flow channel 9. Will now over the at least one inlet 1 a Filler-gas mixture introduced into the filler channel 6, so it comes at the lower end of the sleeve 11 to a turbulence of the filler-gas mixture due to the increase in the diameter. This turbulence leads to an improvement of the mixing of the filler (s) with the reactive mixture flowing out of the mixing chamber 5 and thus to a uniform wetting of the filler (s) with the reactive mixture. The resulting filler-containing reactive gas mixture leaves the flow channel 9 via an outlet opening 7. According to the invention, the flow channel 9 can also have at least one, in particular a plurality of gas channels 3 which are located on the same or different planes. The mixed gas flowing in via the at least one gas channel 3 further agglomerates the filler-containing reactive gas mixture. At the Outlet opening 7 then exits a mixture in which the / the filler (s) is completely and evenly wetted with the reactive mixture / are.

At the end of the weft, filler channel 6 and flow channel 9 are mechanically cleaned by the ejector 8, comprising the sleeve 11 and the core 10. According to the invention, the sleeve 11 is completely inserted into the flow channel 9 at least to the outlet opening 7 for cleaning, so that the at least one opening of the sleeve 11 is at the level of the at least one flow direction of the first gas channel 3. This allows the cleaning of the inside of the sleeve and the lower surface of the core 10 with a gas flow introduced from the at least one gas channel 3 into the sleeve 11. The core 10 is formed so that it, when inserted into the cleaning position in the sleeve 11, with the lower edge of the sleeve 11 is flat.

In a further embodiment of the device according to the invention, the outlet opening 7 tapers in the flow direction.

Claims

claims 1. Device for producing a filler-containing resin spray comprising  a. a cylindrical filling material ka na I (6) with at least one inlet (1), for introducing a mixture of transport gas and filler, and an axially movable ejector (8), b. a cylindrical flow channel (9) for introducing filler from the Fül Istoff ka na I (6) and  c. a cylindrical mixing chamber (5) with at least two inlet openings (4) for the metered addition of at least two reactive components,  wherein the mixing chamber (5) and the filler channel (6) enclose an angle which is not equal to 180 °, while the filler channel (6) and the flow channel (9) enclose an angle of 180 °. 2. Device according to claim 1, characterized in that it further comprises an axially in the mixing chamber (5) movable ejector (2). 3. A device according to claim 2, characterized in that the length of the ejector (2) corresponds to the length of the mixing chamber (5) up to the inlet into the flow channel (9). 4. Device according to one of claims 2 or 3, characterized in that the abutting surface of the ejector (2) is concave, in particular provided with such a curvature which corresponds to the cylindrical shape of the flow channel (9). 5. The device according to claim 1, characterized in that in the flow channel (9) at least one gas channel (3), preferably several gas channels (3) open into at least one level in these. 6. Apparatus according to claim 5, characterized in that two gas channels (3) lie opposite each other on a plane. 7. The device according to claim 5 or 6, characterized in that the at least ei ne gas channel (3) is arranged so that the flow direction of the gas stream when entering the flow channel (9) outside the center of the flow channel (9). 8. The device according to claim 1, which shows that the filling material (6), the mixing chamber (5) and the flow channel (9) have different inner diameters the inner diameter of the Fül Istoff ka na Is (6) is smaller than the inner diameter of the flow channel (9). 9. Device according to claim 1, characterized in that the ejector (8) is at least as long as the filler chamber (6) and the flow channel (9) up to the outlet opening (7). 10. The device according to claim 9, characterized in that the ejector (8) comprises a sleeve (11) and a core (10) movable therein. 11. The device according to claim 10, characterized in that the sleeve (11) in the firing position has at least one opening in the amount of at least one inlet (1) and in the direction of the flow direction in front of the mouth of the mixing chamber (5) in the flow channel (9). ends. 12. The apparatus according to claim 1 1, characterized in that the at least one opening of the sleeve (11) is in the cleaning position in the amount of at least one first gas channel in the flow direction (3). 13. The device according to one of claims 10 to 12, characterized in that the core (10) ends in the firing position in the direction of flow above the at least one inlet (1) and in the cleaning position as far as the flow channel (9) that he with the surface of the lower edge of the sleeve (11) closes. 14. The device according to claim 1, characterized in that the outlet opening (7) tapers in the flow direction.