DE3013511A1 - METHOD FOR THE USE OF SLUDGE REMOVALS FROM INDUSTRIAL PAINTINGS WITH HEAT-HARDENING PAINTING AGENTS FROM SPRAYING CABINS - Google Patents

Description

Method of using sludge waste from industrial paints with thermosetting paints from spray booths.

During industrial application of paint in spray booths, only part of the atomized paint is applied to the Paint applied to the item being knocked down. So that the remaining paint does not stick to the cabin walls settle, a cascade-like veil of water flows over these walls, which absorbs the excess paint. The emerging liquid mixture is collected in a sedimentation tank; after settling and any subsequent filtration the aqueous phase is returned to the water cycle and there remains a more or less viscous than Residue labeled paint sludge.

The invention is particularly concerned with dye sludge that consists of result from thermosetting paints, such as those used for painting car bodies, housings or housings Industrial refrigeration cabinets, washing machine housings and the like can be used. An essential, transformative component Such a paint is a thermosetting synthetic resin which is usually selected from the group consisting of the following thermosetting resins

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ORIGINAL INSPEC ^T ED

selected: polyester, epoxy, alkyd, acrylic, urea and melamine resins. The formulations of such paints vary considerably and are made by the manufacturers generally not communicated in detail. Below are some typical average approaches as examples called; the numbers indicate parts by weight.

Approach I ( opaque synthetic resin paint )

thermosetting resin 33

inorganic pigments 18

mineral fillers 10 solvents:

Alcohols 3

Glycols 4

Aromatics 29

Additives 3

100

Approach II (primer paint)

thermosetting resin 32

inorganic pigments 20

mineral fillers 15

Solvent:

Alcohols 10

Glycols 3

Ester 5

Aromatics 15

100

Approach III (ifletalleffectd corner color )

thermosetting resin 40

Metal particles 3 solvents:

Ketones 12

Alcohols 10

-Forts. 6th

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Ester 5

Glycols 5

Aromatics 25

100

The colors are of the "non-aqueous" type, and therefore they can (and in fact become) unfavorable in the presence of water to a greater or lesser extent can be influenced, so that the recovery of the paint from a sludge for reuse is practical is impossible.

In the various branches of industry there are huge amounts of paint sludge that is very difficult to remove is. In particular, sludges resulting from working with thermosetting paints do not offer any prospect on recovery of the resins or other valuable components contained therein, because water, time and other influences lead to degradation, agglomeration and other changes. The uncontrolled dumping this sludge is not possible for obvious ecological reasons. Incineration or controlled landfill are economically unsatisfactory because of the high investment and operating costs of such systems.

An attempt has been made to use paint slurries containing thermosetting paints; The sludge was first freed from most of the water it contained by mechanical means (in particular by extruding through openings a few millimeters wide) and was then ^{dried for several hours in an oven at a temperature of about 200 °} C. until a product resulted which could be comminuted into appropriately sized particles by grinding and sieving; the resulting particles were then (as

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ORIGINAL

inert filler) mixed with wood particles with the addition of a suitable thermosetting binder (e.g. urea / Formalüehydharζ) for the production of Plates by a hot pressing process according to the usual Process used to manufacture chipboard.

In general, it has also been considered that the binder properties of the resins in thermosetting / oistrichmittel withdrawn sludge again for the Manufacture of chipboard or the like. Exploit, since the resins in question are essentially thermosetting Resins deals; one has rejected the idea from the beginning because of the difficulties which are associated with the treatment of a material (sludge) of gurruni-like consistency, as well as that is sticky, damp, soaked in solvents and contains a wide variety of contaminants (especially mineral and metallic dyes). Yet more significant difficulties would be expected in drying the specified material when it comes to its thermosetting properties should not be affected.

According to the invention a method is provided at the waste sludge from industrial paints with thermosetting paints from spray booths are used; According to this process, the sludge is used in conjunction with other components for the production of fiber-reinforced thermosetting plates are used, and the method is essentially characterized in that the taser material mixed with aem sludge (added to the sludge) as long as it is still in a moist, plastic is in state and has a water content of at most 35 wt. * (preferably between 10 and 20%), and although without the addition of a commercially available heat-retaining resin,

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. BATH. ORIGINAL

and that the plate using mechanical pressure is produced at a temperature sufficient to at least partially thermoset the in the Bring about sludge containing resin.

It follows from this that the sludge does not have to be completely dry for the purpose according to the invention? the one given above reduced residual water content can be achieved by mechanical treatment, for example by pressing, rolling or Extruding, which allows excess water to be forced out of the mud. In addition, the (obviously expensive use of suitable commercially available thermosetting binders of the urea type / Formaldehyde resin or the like. Dispensable, because among the inventive Process conditions will be the bondability of the thermosetting resin contained in the slurry exploited; this bondability is sufficient for the purposes of the present invention.

In thermosetting paints, such as, for example Resins used for painting car bodies are mostly alkyd-melamine resin or acrylic-melamine resin type contain. Slurries containing other thermosetting resins, especially those of the ones mentioned above Types can also be used in the context of the present invention.

For example, a sludge that is produced in the case of a topcoat after it has settled in a settling tank, have the following weight composition (IV):

Binder (resin) 35%

Titanium dioxide 16.4%.

Iron 0.25%

Silica 0.74%

Calcium 0.3%

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BAD ORi.OiNAL '

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Magnesium 0.03%

Chromium oxide 0.7%

Lead 0.3%

Water and solvent 46.28%

A sludge that is created when painting with a primer paint can be composed (in terms of weight) as follows his (V):

Binder (resin) 26% Tityn dioxide 35.1 Silicon dioxide 0.2 iron 0.18 Calcium 0.5 magnesium 0.2 phosphate 0.2 Water and solvents 37.62

In the context of the present invention, it is of no importance whether, for example, the sludge of a topcoat with sludges are mixed, which result from a primer, as is often the case in practical operation.

The following substances, for example, come into consideration as fiber material:

- plant fibers such as coconut, jute, cotton, wood fibers, loose or in the form of mats;

- synthetic fibers such as polyamide, polyester, acrylic, vinyl, polyolefin fibers, preferably in the form of Mats or felts;

- Reclaimed material, such as rag waste, different

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ORKSfNAL INSPECTED

Licher kind in the form of mats, chipped or ground;

Press plates of different material composition, such as shredded rags, shredded paper, sawdust or sawdust and wood wool or asbestos fiber residues;

woven fibers of animal, vegetable or synthetic origin, woven asbestos fibers, glass wool or Mineral wool;

Mineral fibers such as asbestos fibers, glass wool, mineral wool, preferably in plate or mat form.

According to one embodiment of the invention, the Combination of the fiber material with the sludge by producing a layer structure from a layer of sludge achieve fiber material with at least one plate or mat. In this case, it is useful to squeeze out to make the sludge at the beginning by rolling between drums, so that there is a plate that is between can bring two plates or mats made of fiber material. The layer of mud can vary in thickness and in general vary between 0.2 and 10 mm, depending on the permeability of the two fiber material plates or mats.

According to another embodiment, the method can the fibrous material combine with the sludge by the squeezed-out sludge and the loose fiber material are directly combined with one another by mixing or kneading. This process is preferably carried out at a temperature above ambient temperature, so that a reduction the sludge viscosity takes place without the addition of solvents (which can only be recovered at high cost recovered). The preferred temperature is

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between about 40 ° C and about 80 ° C, but should in no case be so high that this process step undesired crosslinking of the resin can occur. Temperatures of the order of 100 to 110 ° C can be accepted, but may only last a few minutes (for example 10 minutes at 110 ° C). That the The product leaving the roller kneader has plate or sheet form and contains the fibrous filler material; the layer can then be hot-pressed in this state or with outer layers made of paper, textile fabric or other material be provided.

The weight ratio of sludge to fiber can vary widely, between about 1: 4 and up to about 9: 1. At ratios below 1: 4, a homogeneous sludge-fiber connection can hardly be achieved, while at At ratios above 9: 1 an extremely brittle material can arise when the panels are pressed at temperatures above 150 ° C, or an extremely plastic material if temperatures below 100 ° C is pressed.

As indicated above, the plate is made by applying mechanical pressure and a sufficiently high temperature manufactured.

The mechanical pressure, which favors the elimination of both the residual water and the solvents, leaves exercise by using a hot platen press.

For continuous operation, calendering through hot drums or on endless hot plate conveyors is recommended. preferably with several calender passes. The minimum pressure required is 0.5 kg / cm in all cases

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The temperature can vary between 80 ° C and about 220 ° C. At temperatures below 100 ° C they result very flexible, relatively plastic plates, and the removal of the residual water takes place slow and incomplete. For this reason, temperatures above 100 ° C and preferably above 150 ° C are preferred. If rigid panels are to be produced, temperatures between 175 ° C and 220 ° C are recommended. The treatment time is generally inversely related to the temperature and the plate thickness. at low thickness and temperatures in the range of about 200 to 220 ° C, two minutes are sufficient. For stiff panels of the type mentioned above generally take 5 to 15 minutes. If you work for a - generally recommended - Temperatures of more than 150 ° C, the plate dries out practically completely, if one is sufficient long treatment time is chosen. According to a preferred embodiment of the method, the hot pressing takes place advantageously with increasing temperature, starting from a temperature below 100 ° C, so that initially the drainage is favored and only then the networking; in this procedure and in use of the fiber material in layer or mat form, it is recommended according to the invention to apply pressure from the start work suitable for the penetration of the material with the mud, and this pressure during the following Maintain treatment steps.

example 1

A sludge made from an indefinite number of painting cycles with primer and topcoat originated, was pressed at 25 ° C through a slot 2 × 50 mm in size and then down to a thickness of

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1 mm cold rolled; the remaining water content was about 20%. The layer obtained in this way was placed between two mats made of vegetable fiber (preferably jute fiber); the weight per unit area of the mats was 430 g / m ² .

The plate was pressed on a table press at 5 kg / cm ² i
duration 20 min.

at 5 kg / cm pressure and a temperature of 190 ° C; Press

The result was a plate about 2 mm thick, whose modulus of elasticity was 20,000 and whose flexural strength was about 220 kg / cm ² .

Example 2

Flaps made of polyamide material were ground until fibrils 2 to 3 mm in length resulted. Then was the mass compacted by hot pressing, so that a felt about 2 mm thick resulted. The felt was between two Laying layers of mud 0.6 mm thick; the sludge layers were made according to Example 1 and had a Residual water content of about 15%.

The pressing takes place on a table press at a pressure of 2 kg / cm and a temperature of 175 ° C; Pressing time 10 min. The finished panel has a tensile strength of about 50 kg / cm and a modulus of elasticity of 4500.

Example 3

The procedure was as in Example 1, but the

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ORlGfNAL INSPECTED

Heat treatment time increased to 30 minutes. The finished panel had a modulus of elasticity of 20,000, one

> n
2

Flexural strength of about 230 kg / cm and a tensile strength of 200 kg / cm

Example 4

Waste pieces (chips) from a shirt factory (70% cotton fibers and 30% polyethylene terephthalate fibers) were frayed until fibrils 2 to 6 mm in length were obtained. 30 parts by weight of fibers were mixed with 70 parts by weight Paint sludge connected, the composition of which corresponded to the formula (V); the water content of the Sludge had previously been reduced to 8% by weight by repeated extrusion into thread-like material. Mixing took place at about 50 ° C and the mass was calendered at ambient temperature so that a Layer 2.5 mm thick was created. Both sides of the mud layer A layer of Kraft paper was placed on top and this sandwich material was placed in a tabletop press and exposed there to a pressure of 0.5 kg / cm at 180 ° C. for 30 minutes. The result was a plate with a flexural strength

2

speed of 182 kg / cm, a tensile strength of 134 kg / cm and a flexural modulus of elasticity of 14,600 kg / cm.

Example 5

The mud used was exactly the same Example 4 and had a residual water content of 8% by weight. The mud was rolled at ambient temperature, so that a layer of 1.5 mm thick was formed. On each side of the mud layer was a mat of evenly oriented Glass fibers laid. The total percentage of fibers

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the sludge layer was 40% by weight. The sandwich material was pressurized on a table press for 10 minutes at 190 ° C. at 0.5 kg / cm. The result was a plate approximately 2.3 mm thick, with a flexural strength of 295 kg / cm ² and a flexural modulus of elasticity of 27,200. The tensile strength in the fiber direction was 468 kg / cm and across it 323 kg / cm. For test purposes, the plate was immersed in water until there was no more weight gain (ie until it was saturated with water); the water absorbency determined in this way was only 6.5% by weight.

Example 6

A topcoat was used in a spray booth, which was composed of (percent by weight): about 25% alkyl resin, about 10% melamine resin, about 18% inorganic pigment, about 10% mineral fillers, about 36% organic solvent and about 1% Stabilizers; the sludge collected contained the paint mentioned above and about 40% water. The slurry was forced through a 2 × 50 mm slot at 25 ° C. and then closed at ambient temperature a layer of 1.5 mm thick with 15% water content. At the same time, one was needled on kraft paper Mat made from jute fibers. Two such mats were placed on both sides of the layer of mud, with the paper side facing out; the connection with the sludge layer was carried out under a pressure of 10 kg / cm at ambient temperature. The plate is hot-pressed on a table press at 180 ° C 25 kg / cm for the first 2 min. And then for 4 min. At 0.5 kg / cm. The resulting plate had a bending

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2
strength of 273 kg / cm, a flexural elasticity

2 modulus of 26 200 and a tensile strength of 201 kg / cm

Example 7

A paint sludge was collected consisting of about 33% by weight acrylic and melamine resin, about 16% pigment and filler, and about 51% aqueous liquid containing only traces of organic solvents. The mass had a cellular structure and the cells were filled with the aforementioned aqueous liquid. The water was squeezed out of the sludge by repeated rolling at 20 ° C. until a residual water content of about 15% remained. The resulting layer (about 1.5 mm thick) was placed between two layers of loosely woven glass fibers, the total weight of which was about 30% of the weight of the sludge layer. The tissues were preliminarily bonded to the sheet by compression at 30 kg / cm at 20 ° C. This was followed by hot pressing on a table press (15 minutes at 190 ° C. with 0.5 kg / cm). The resulting plate had a modulus of elasticity of 29,800, a flexural strength of 376 kg / cm ² and a tensile strength of 320 kg / cm ² . The water absorption (when saturated) was only 9% by weight.

It is readily apparent to anyone skilled in the art that hot pressing between embossed or, generally speaking, non-planes Printing plates can be made so that embossed or three-dimensional plates are created.

Thanks to the favorable properties that are listed in the examples above, the panels can be Use in many ways and exchange for plates that were previously made with expensive raw materials

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have been manufactured (this includes, for example, commercially available synthetic resin approaches for pressing). A practical one The advantage of the invention is also to be seen in the fact that the proportion of the sludge starting material in the finished plate is relatively high; this means that you have to deal with the extraordinarily large amounts of paint sludge, that arise daily in the spraying systems of a company, can be disposed of without difficulty can, especially without the need to use large amounts of material from external sources. Furthermore, because of the low water absorption of glass fiber reinforced Plates, for example according to Examples 5 and 7, these plates (and similar plates, which for example are made using rock wool or slag wool) particularly favorable for roofing, for barracks and similar utensils, which are constantly thousands of square meters Covers or panels are needed. Instead of the usual asbestos-cement corrugated sheets, corrugated Use plates according to the invention with success. Plates produced according to the invention can also be advantageous be used as interior upholstery in automobiles and railroad cars.

The color of the panels produced according to the invention is mostly indeterminate or accidental because of the sludge collected usually comes from painting with different colored paints. Naturally but one color of the plate can be reinforced, or you can make colored plates in general, if you adding suitable pigments to the sludge. If necessary, fluorescent pigments can also be added.

The patent attorney

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Claims (12)

Expectations : Process for the use of waste scraps from industrial paints with thermosetting paints from spray booths, in which the sludge is in contact with other components are used to manufacture a fiber-reinforced thermosetting panel, characterized in that the fiber material with the sludge, while this is in plastic, moist State and has a water content of at most 35% by weight, without the addition of a commercially available thermosetting agent Resin is bonded so that the only thermosetting binder is the binder contained in the sludge and that the plate is manufactured using mechanical pressure at a temperature which sufficient to bring about an at least partial thermal hardening of the resin contained in the sludge. 2. The method according to claim 1, characterized in that the connection of the fiber material is made with the sludge is made by making a layer material from a layer 030043/0832 1 3 5 Mud and at least one layer or mat of
called fiber material is formed. 3. The method according to claim 1, characterized in that the joining of the fiber material with the sludge by Kneading takes place. 4. The method according to claim 3, characterized in that the hot kneading is carried out at a temperature and within a time sufficient for heat setting not enough. 5. The method according to claim 1, characterized in that 2
the mechanical pressure is at least 0.5 kg / cm. 6. The method according to claim 1, characterized in that the temperature between 80 and 220 ° C is kept un their application time is at least 2 minutes. 7. The method according to claim 6, characterized in that
the said temperature is above 100 ° C. 8. The method according to claim 6, characterized in that
that di
lies. that said temperature is between 175 ° C and 200 ° C 9. The method according to claim 1, characterized in that 030Ö43 / 083I BAD ORiO'M AL the plastic sludge with a water content of at most 35% by weight by expelling the excess Water is obtained from the starting sludge by mechanical means. 10. The method according to claim 9, characterized in that the starting sludge mechanically by extruding or rolling is treated. 11. The method according to claim 9 or 10, characterized in that that the maximum water content of 35% is at least 10%. 12. The method according to claim 1, characterized in that the weight ratio of sludge to fibers between 1: 4 and 9: 1. 030043/08 3 7