DE19822810A1 - Material for protecting surface during mechanical or (photo)chemical treatment, e.g. etching or sand blasting - Google Patents

Abstract

Material for protecting surface during mechanical, chemical or photochemical treatment consists of at least 2 components (A, B), which are mixed just before application to the surface.- DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the process for protecting surfaces with this material

Description

The invention relates to a material and a method for Protection of surfaces during treatment with mechanical, chemical or photochemical agents.

For chemical or mechanical treatments of surfaces are not to be according to the known prior art acting surfaces through a protective layer that both is applied to the surface to be treated, po sealed tight. Only the surface to be treated is either not protected or before treatment process removed from the applied protective layer, so that the chemical or mechanical action ensures who that can.

After the respective treatment process, the protective layer away. It can then either be another in the subsequent step same treatment with the same method (e.g. more etching or blasting) or a new, different one Processing step take place (e.g. etching or blasting a Surface and subsequent painting process).  

Products containing solvents are often used as protective layers different character used such. B. bituminous Products, co-polymers etc. Pasty products also come or waxes or fats of all kinds. Also the use of self-adhesive protective films under A wide variety of chemical compositions should be mentioned.

All of these processes have application disadvantages, either in terms of environmental protection or process processing time or the applicability at complicated molded parts come into play.

So have solvent-based, non-aqueous protective coating For example, the disadvantage of extreme environmental pollution due to the generation of solvent vapors during processing tung. In many cases the solvent content is more than 70% of the protective coating.

The flash point of such a protective coating material is often very low when delivered (<5 ° C).

Suction using suitable filters (e.g. Ak charcoal) must create a humane working atmosphere. It must be a time consuming manufacturing step in manufacturing can be scheduled to prevent the solvent from evaporating accomplish. The regeneration of the solvents must also be carried out be made. Accordingly, the need arises the environmentally friendly disposal of the regrind solution tel and the materials containing solvent residues.

Aqueous protective coatings currently frequently fulfill not with regard to the requirements placed on them  fast, reliable processing and adequate chemical Resistance.

Pasty products and fats, waxes etc. need to be removed tion by thermal processes or rinsing processes, the part again refer to the use of non-aqueous solvents long. This raises the problem of environmental pollution evident.

The use of protective films is for complex shaped Difficult to share and time consuming. It is therefore the job of Invention, a material and a method for protecting Surfaces when treated with mechanical, chemical or photochemical means available, wel ches causes significantly lower environmental pollution and nevertheless, we also have very complicated surface structures can protect protectively. According to the invention, this task like with a material. Claim 1 or a method according. Claim 18 solved.

The subclaims describe further preferred embodiments tion forms of the invention.

The invention provides a sprayable, a pourable and a spreadable variant of the material is available, so that all processing options are available.

The invention includes aspects of material procurement the properties of the sealing layer, the appli cation of this material and the processing method.  

In contrast to the seals known hitherto, the subject matter of the invention is a chemical substrate which surface during application to the metal surface

Polycondensation
Polymerization or
Polyaddition

reacts to the polymer material.

The preferred reaction is a polyaddition of one or multiple reactants.

In the simplest case of polymer formation in "in-situ" from two starting materials. One of the raw materials is preferably characterized by the presence of acidem Hydrogen according to Zerewitinoff.

Furthermore, the additives of kata are in this starting material analyzers and activators that control the speed and off Accelerate curing, preferred for this process. In In specific cases, an organic or inorganic filler can be added. As a filler offer all non-abrasive solids.

Polyester alcohols are suitable as polyadditive substances, Polyether alcohols with a high polymer content, such as dispersions polymeric urea (PHD) or styrene-acrylonitrile Copolymer (SAN), polymethylene polyureas or melami nen, diamines, polytetrahydrofuran, polybutadiene, mixtures from several of these substances, as well as pre-adducts and hybrids,  Diols, triols, especially triols with only prioma ren hydroxyl groups and polyether alcohols based on these Triols, aliphatic, aromatic or cycloaliphatic seg organic acids containing at least two car boxyl groups.

The catalysts used are tertiary aliphatic, cycloaliphatic tables, bicycloaliphatic and aromatic components Ver turn.

Also organometallic compounds and / or organic Paroxides and / or ketones can be used.

The second starting material is a substance that rer chemical structure also for the polyaddition reaction by accepting the acidic proton and splitting dop is capable of fur bonds. With this raw material it can are at least two functional aliphatic, aromati organic compounds and / or pre-adducts of ali phatic and / or aromatic organic compounds with Substances that contain an acidic proton act.

Both raw materials can be independent of the physical state be used. However, it is recommended to use liquid components in the viscosity range of 25000 mPas to 50 mPas, preferably in the range of 400-8000 mPas 25 ° C.

In a special embodiment, the use of dehumidifying agents, so-called aluminosilicates em commendable. The content should be between 1.5% and 20% gene, preferably between 3 and 15%.  

In a multi-component embodiment, the Polyad mixture of polymers with different types of polymer formation promotions such as unsaturated polyesters, polycarbonates, polyme thylenmelamine, etc. or thermoplastic polymers and thermoplastic polyurethanes are added. The amount of these components can be 0.5% -50%, preferably 5% -30% be.

The components, whether two-component or multi-component mixtures have to be reactive. They have different reacts activity profiles. The reaction should start within 0.5 s to 30 s at an ambient temperature of 25 ° C at a sprayable variant and within 30 s to 30 min. at one pourable, and 5 min. up to 180 min. at a spreadable variant.

The polymer should be within the sprayable variant hardened within 10-60 s. The pourable mixture should within 5 min. up to 90 min. harden and spread mixture within 15 min. up to 420 min (7h).

The polymer should have good elasticity in the fully reacted state act. The elongation at break should be between 100% and 700% lie, but preferably between 250% and 600%. The Shore hardness of the polymer should be between 30-95 Shore A. preferably 50-92 Shore A.

The polymer material must be resistant to chemical sub punch, such as acids and bases and various mordants. This Resistance and thus the protective effect is only for the period of use, i.e. the duration of treatment of the  Surface of importance or as in the case of the temporary Corrosion protection for the period of the desired protection. Also the resistance to photochemical influence and against mechanical impact from particles that are generated by blasting procedures must be guaranteed.

The polymer should be able to be cut with laser beams. With this cutting technique, the polymer must be free of residues and / or with controlled adhesive thicknesses behind the cutting edge can be cut. The adhesion of the polymer material to the surface may be in the contact area of the laser beam, especially at the interfaces of the remaining Protective film, do not get lost because of chemical treatment lungs in z. B. caustic baths the reduction of liability in Contact area causes an underwashing of the polymer. A such undermining leads to inexact etching of the surface che in the border area.

The adhesion of the polymer should be an initial value in the normal case 20-800 gcm ^-1 and in the case of the use of this polymer material preferably 50-300 gcm ^-1 according to the frequently used pellet method. This liability value should not fall off in the course of a chemical treatment, but should remain constant or be improved. It should ideally be so large that the tensile strength and tear strength of the polymer is so much greater than the pell force that the polymer can be removed from the surface in one operation without great effort and without great effort.

It is essential that the polymer remains free of residues Metal surface can be peeled off and the same in the green  most cases processed without further treatment that can.

The consistency of the raw materials must be chosen so that good mixing with simple processing machines, ensures the optimal homogeneity of the polymer can be. Both the sprayable and the pourable capable variant, the polymer film must have a layer thickness of 50 Micrometer (Micron) up to 500 Micrometer (Micron), preferred reach 100-300 microns (micron). The streakable This variant should have a layer thickness of 25-250 micrometers (Micron) can be applied. Thinner or thicker layer thickness ken often only have consumption disadvantages without an improvement effect of the procedure.

By applying the procedure and applying the Polymer material is a change in the structure of the respective metallic material largely closed.

This polymer material can be used for all applications in de changes on a metallic surface surface quality and / or a reduction in wall thicknesses should be aimed as an "in-situ" protective layer with itself adhesive properties on grease and corrosion-free surfaces surfaces are used. The advantage of the invention Polymer material is the fact that in addition to good cor Protection against corrosion also good chemical resistance to alkalis and has acids. Due to a precisely set haf tion, the polymer material can be treated, untreated (but dust and grease free) or painted metal top surfaces can be removed without residue by pelleting. To  Mention should be made of the fact that laser cuts are also clean can be carried out. It should also be mentioned that the water after curing and / or use shredding and / or grinding in turn as an environmentally friendly Re Generat can be installed in new materials or on due to the calorific value in briquetted form of the thermal Recovery can be supplied.

Possible applications are:
Sealing of metal surfaces against chemical influences, e.g. B. etching.

This seal is particularly important for etching processes, those in the aerospace industry or in the automotive bilindustrie or the tool and mechanical engineering on aluminum materials for the purpose of changing wall thicknesses without Change in the structure of the aluminum material be performed.

In one embodiment of this application, the metal surface by repeated immersion in warm etching baths from Sodium hydroxide solution with small amounts of additives 80-85 ° C specifically etched to the desired thickness. Special Care must be taken to limit the adhesion of the polymer material area to the protected aluminum part, d. H. partial loosening of the protective layer leads to creeping the etching liquid under the polymer material and to a not acceptable because of unclean cut on the etch edge. The polymer material according to the invention fulfills in all Modifications to this requirement.  

Some examples of other possible uses are:

• 1. Temporal corrosion protection for vehicles (instead of Wax treatment) of all kinds, e.g. B. Transport protection at Automo and all types of machines and machine parts and Devices.
• 2. Protection of untreated surfaces on buildings and Apparatus that is blasted. Here also can be non-metallic surfaces such as plastics and stone surfaces to be protected.
• 3. Temporary protective film for electronic goods and equipment te, as well as filling material with acceptable properties at Use of electronic components in lamps, capacitors and coils.

Spray application

You use the attachment of the polymer material standard methods. On dosing machines for two or Multi-component systems are the raw materials in low pressure or high pressure process using a suitable mixing head homo mixed together. It is very important speed that from the beginning to the end of the volume flow Consistent mixing quality with low air pollution is enough. To do this, a mix is preferably used head with a downstream, rotating static mixer or a mixing head with static mixing by Umlenkka channels. The reaction mixture must pass through suitable nozzles Reaction chamber are injected.  

As excellent nozzles have preferably spe ziell omnidirectional nozzles, made of metal, ceramic or Plastic with nozzle diameters of 0.2-1.5 mm, those in the component pressure range from 20 to 250 bar, preferred be operated in the range of 50 to 150 bar.

When processing the components, the temperature is extremely important. In general, the ver working temperatures at 30-60 ° C for two-component sy steme. In the polymer materials according to the invention, the most favorable processing temperature in the range between 60 and 100 ° C, preferably between 65 and 80 ° C.

The geometry of the mixing head and of the nozzles and the discharge rate of the metering pumps stalt that the volume flow from the mixing head turbulent exit. A post-mixing with air or other gases is not necessary.

Casting application

For this application you can use the same machines as above be used. The same goes for the mixing heads, surprisingly the same round jet nozzles Metal, ceramic or plastic with nozzle diameters from 0.2 1.5 mm can be used.

By adjusting the flow rate of tur belent after laminar can be an excellent cast product with very good properties can be achieved.  

Brush application

This application includes all manual methods of the An bringing the polymer material according to the invention, also are known from paint processing. It's just on the different viscosities of the reaction mixture, zube by stirring from the starting reaction components is riding to watch out. These viscosities are increasing increasing response time. It should therefore be special on the use of water-absorbing agents, the foam bil prevent environmental reactions with the ambient humidity, geach be tested. Usual hand tools for spreading the poly brushes of all kinds, Fur roller, etc. The layer thicknesses to be applied are in generally thinner than that used in casting and spraying applications.

The following are some embodiments for which he material according to the invention.

1. A typical example of a spreadable poly urine Substance formulation consisting of the following components A and B with equal volumes of the two being mixed:

The A component (polyol fraction) consists of:

0.1-0.3 mol of polyoxyalkylene diamine with a molecular weight of 2000 to 6000 daltons and
0.9 to 0.7 mol aromatic diamine.

The B component (diisocyanate fraction) consists of:

0.87 mol diisocyanate;
0.01 mol of polyoxyalkylene amine with a molecular weight of 2000 to 6000 daltons and
0.12 mol of polypropylene glycol with a molecular weight of 1000 to 4000 daltons.

2. Another example is a hybrid formulation of Po specified lyurethane polyurea, in which the two compo components A and B are structured as follows:

A component (polyol fraction)

0.2-0.4 mol polyether-acrylonitrile-styrene copolymer with a molecular weight of 2000-4000 daltons
0.8-0.6 mol aromatic diamine, sieved at 10 pph through molecular sieve 3 Å
0.2-0.8 (% (w / w)) double cyclic tertiary amine catalyst
0.01-0.15 (% (w / w)) organometallic catalyst

B component (prepolymer based on MDI)

Consisting of a prepolymer of polyether polyol and MDI. A typical composition for this is:

0.87 mol of polypropylene glycol and
0.13 mol pure (monomeric) MDI,

where a free NCO content of the prepolymer of 9.8 (% (f / f)) results.

3. Another example of a mixed formulation for a Polyurea type coating:  

A component (polyol fraction)

0.2-0.4 mol polyether-acrylonitrile-styrene copolymer with molecular weight of 2000-4000 daltons.
0.8 to 0.6 mol aromatic diamine sieved at 10 pph through 3 Å molecular sieve

B component consisting of a prepolymer, which synthe is made of a polypropylene polyol and pure MDI such a composition that the polypropylene glycol in 10 times molar excess is present over the MDI, whereby a free NCO content of the prepolymer in the range of 16 (% (f / f)) results.

Claims (33)

1. Material for the protection of surfaces during treatment with mechanical, chemical or photochemical means, characterized in that the material consists of at least two components (A, B), which are mixed shortly before application to the surface to be protected. 2. Material according to claim 1, characterized in that the Material only after the mixed components have been applied ten (A, B) on the surface to be protected by polycondensation sation, polymerization or polyaddition is formed. 3. Material according to claim 1 or 2, characterized in that only two components (A, B) are present, of which the an (A) acidic hydrogen according to Zerewitinoff and possibly the contains required catalysts and activators, while the other (B) for the acceptance of acidic hydrogen and for Is capable of splitting double bonds. 4. Material according to claim 3, characterized in that component (A) contains one or more of the following substances ent:
Polyester alcohols, polyether alcohols with a high polymer content, such as dispersions of polymer urea (PHD) or styrene-acrylonitrile copolymer (SAN), polymethylene-polyurea substances or melamines, diamines, polytetrahydrofuran, polybutadiene, mixtures of several of these substances, as well as pre-adducts and hybrids Diols, triols, in particular triols with exclusively primary hydroxyl groups and polyether alcohols based on these triols, organic acids containing aliphatic, aromatic or cycloaliphatic segments with at least two carboxyl groups,
and that component B contains one or more of the following substances:
At least two functional aliphatic, aromatic organic compounds; Pre-adducts of aliphatic and / or aromatic organic compounds with substances that contain an acidic proton. 5. Material according to claim 3 or 4, characterized in that as catalysts tertiary aliphatic, cycloaliphati cal, bicycloaliphatic and aromatic components or organometallic compounds and / or organic peroxides and / or ketones are used. 6. Material according to one of claims 1 to 5, characterized ge indicates that it is a non-abrasive organic or contains inorganic filler. 7. Material according to any one of claims 1 to 6, characterized ge indicates that the components (A, B) are liquid in one  Viscosity range from 25,000 mPas to 50 mPas, preferably 8000 mPas to 400 mPas at 25 ° C. 8. Material according to one of claims 1 to 7, characterized ge indicates that it additionally 0.5% to 20%, preferably 3% to 15% dehumidifiers, preferably Contains aluminosilicates. 9. Material according to one of claims 1 to 8, characterized ge indicates that this is an additional component of 0.5% to 50 %, preferably 5% to 30% of polymers with different types of poly merformation reactions such as unsaturated polyesters, polycarbo nate, polymethylene melamine, etc. and / or thermoplastic Contain polymers and / or thermoplastic polyurethanes are. 10. Material according to one of claims 1 to 9 for processing tion by spraying, characterized in that the reaction of the components at process temperature within 0.5 s to 30 s starts and the material cures after 10 s to 60 s is. 11. Material according to one of claims 1 to 9 for processing tion by pouring, characterized in that the reaction of the components at process temperature within 30 s to 30 min. starts and the material after 5 min. up to 90 min. is cured. 12. Material according to one of claims 1 to 9 for processing tion by brushing or rolling, characterized in that the reaction of the components at process temperature within  from 5 min. up to 180 min. starts and the material after 15 min. up to 420 min. is cured. 13. Material according to one of claims 1 to 12, characterized ge indicates that the elongation at break in the hardened state between 100% and 700%, preferably between 200% and 550 % lies. 14. Material according to any one of claims 1 to 13, characterized ge indicates that its Shore hardness in the hardened state between 30 and 95 Shore A, preferably at 50 to 92 Shore A lies. 15. Material according to one of the preceding claims, since characterized in that his liability to the protected Surface according to the pell method 20 to 800 g / cm, preferably Is 50 to 300 g / cm. 16. Material according to one of the preceding claims Processing by spraying or pouring, characterized net that the thickness of the polymer film after curing 50th to 500 microns, preferably 100 to 300 microns. 17. Material according to one of the preceding claims for processing processing by brushing or rolling, characterized, that the layer thickness of the cured material 25 to 250 µm is. 18. Methods for protecting surfaces during treatment by mechanical, chemical or photochemical means, in which a protective layer made of a polymer material on the is applied to surfaces to be protected, characterized  records that at least two components (A, B), the mitein react differently to the polymer material, only shortly before Apply to the surface to be protected. 19. The method according to claim 18, characterized in that the polymer material only after the two have been applied mixed components (A, B) on the surface to be protected by polycondensation, polymerization or polyaddition forms. 20. The method according to any one of claims 18 or 19, characterized characterized in that only two components (A, B) are used , of which the one (A) acidic hydrogen after Zerewitnikoff and possibly the necessary catalysts and Contains activators, while the other (B) to accept the acidic hydrogen and for breaking double bonds is empowered. 21. The method according to claim 20, characterized in that the component (A) contains one or more of the following substances:
Polyester alcohols, polyether alcohols with a high polymer content, such as dispersions of polymer urea (PHD) or styrene-acrylonitrile copolymer (SAN), polymethylene-polyurea substances or melamines, diamines, polytetrahydrofuran, polybutadiene, mixtures of several of these substances, as well as pre-adducts and hybrids Diols, triols, in particular triols with exclusively primary hydroxyl groups and polyether alcohols based on these triols, organic acids containing aliphatic, aromatic or cycloaliphatic segments with at least two carboxyl groups
and that component (B) contains one or more of the following substances:
At least two functional aliphatic, aromatic organic compounds; Pre-adducts of aliphatic and / or aromatic organic compounds with substances that contain an acidic proton. 22. The method according to claim 20 or 21, characterized in net that as catalysts tertiary aliphatic, cycloali phatic, bicycloaliphatic and aromatic components or organometallic compounds and / or inorganic per oxides and / or ketones can be used. 23. The method according to any one of claims 18 to 22, characterized ge indicates that component (A) and / or component (B) a non-abrasive organic or inorganic fill substance is added. 24. The method according to any one of claims 18 to 23, characterized ge indicates that the components (A, B) on a viscose range from 25000 mPas to 50 mPas, preferably 8000 mPas up to 200 mPas can be set at 25 ° C. 25. The method according to any one of claims 18 to 24, characterized ge indicates that component (A) and / or component (B) additionally 0.5% to 20%, preferably 3% to 15% dehumidifiers, preferably aluminosilicates be added.   26. The method according to any one of claims 18 to 25, characterized ge indicates that when components (A, B) are mixed an additional component in the amount of 0.5% to 50%, preferably 5% to 30% is added, which is made of polymers with different types of polymer formation reactions such as unsaturated Polyester, polycarbonate, polymethylene melamine, etc. and / or thermoplastic polymers and / or thermoplastic polyu rethanen exists. 27. The method according to any one of claims 18 to 26, characterized ge indicates that the mixed components by spraying processed, and the components are set so that the reaction of the components at process temperature inner half of 0.5 sec. to 30 sec. and the material hardened after 10 sec. to 60 sec. 28. The method according to any one of claims 18 to 26, characterized ge indicates that the mixed components by pouring are processed, and are set so that the reaction the components at process temperature within 30 sec. up to 30 min. starts and the material after 5 min. to 90 min. is cured. 29. The method according to any one of claims 18 to 26, characterized ge indicates that the mixed components by painting or rolls are processed and are set so that the reaction of the components at process temperature within from 5 min. up to 180 min. starts and the material after 15 min. up to 420 min. is cured. 30. The method according to any one of claims 18 to 29, characterized ge indicates that the mixed components by spraying  and pour in such a thickness on the upper to be protected surface are applied that the thickness of the polymer film after curing 50 to 500 microns, preferably 100 to 300 microns is. 31. The method according to any one of claims 18 to 30, characterized ge indicates that the mixed components by painting or rolls are processed, and in a thickness on the to be protected surfaces are applied so that the Layer thickness of the cured material 25 to 250 microns wearing. 32. The method according to any one of claims 18 to 31, characterized ge indicates that the mixed components at a tempe temperature between 60 and 100 ° C, preferably between 65 and 80 ° C can be processed. 33. The method according to any one of claims 18 to 32, characterized ge indicates that the components (A, B) in low pressure or High pressure process on dosing machines for two or more component systems homogeneous via a suitable mixing head are mixed together, the mixing head with a downstream, rotating static mixer or with a static mixing is provided by deflection channels, and the reaction mixture via omnidirectional nozzles made of metal, ceramic or plastic with nozzle diameters from 0.2 to 1.5 mm in the reaction chamber is injected with the components with a pressure of 20 to 250 bar, preferably 50 to 150 bar can be driven through the round jet nozzles.