Priming composition comprising aromatic polyurethane polyol, method for applying cover, method for car finishing

FIELD: chemistry of polymers.

SUBSTANCE: invention relates to aromatic polyurethane polyols used as components of priming compositions. Invention describes the priming composition comprising aromatic polyurethane polyol including product of reaction: (a) at least one diol component among number of α,β-diols, α,γ-diols and their mixtures; (b) at least one triisocyanate; (c) at least one diisocyanate wherein at least one isocyanate is aromatic one, and molecular mass or aromatic polyurethane polyol is 3000 Da, not above, and a cross-linking agent also. Prepared aromatic polyurethane polyol shows viscosity value by Brookfield at the level 8260 centipoises, OH-number 192.6 KOH/g and the dispersity (Mn/Mw) at the level 3.0. Priming compositions prepared by using indicated aromatic polyurethane polyol are useful in finishing large means of transportation, for example, trains, trucks, buses and airplanes, in particular, in vehicle body works. Also, invention relates methods for applying priming compositions on support comprising applying indicated compositions, and to a method for finishing car in repairs comprising applying the indicated priming composition.

EFFECT: improved and valuable properties of composition.

11 cl, 5 tbl, 12 ex

Background of the invention

The present invention relates to aromatic polyurethane polyols used as compositions for coatings, particularly as coatings applied to metal substrates. More specifically, the present invention relates to aromatic polyurethane polyols, containing the reaction product of diisocyanates, triisocyanate and diols, where at least one is aromatic isocyanates. The resulting aromatic polyurethane polyols are low molecular weight oligomers (typically srednekislye molecular weight (Mn)<3000), intended for use as part of a composition for coating which when cured forms a coating with good mechanical and chemical properties.

Data aromatic polyurethane polyols derived from a special class of diols (α,βand/or α,γ-) in order to ensure selectivity and to synthesize the polyurethane polyol of low molecular weight and relatively low viscosity.

It should be noted that in accordance with how it is used herein, the term "polyurethane polyol" refers to the reaction product, where the reagents (diol component and a polyisocyanate component (s)) are connected in basically the only by urethane links. This is different from (a complex polyester-urethane polyol and from the acrylate polyols modified with urethane, in which the reagents are joined by urethane, through ester linkages.

Currently, the automotive industry and the industry associated with the trim of car repair in increasing the extent of use of the coating system containing primers, the main cover and non-pigmented coatings. In such systems, in General pigmented coating is applied over a suitable primer and coating system finish, through application of non-pigmented transparent top coat coverage over primary pigmented coating. In some cases the use of the coating in the form of pigmented monolayers. Data composition for coatings in General come in the form of systems in "one package" or "two-packs". In the conventional system in one package all the ingredients for the coating are combined in one stable during storage of the mixture. When applying polyol as one component crosslinks, in the General case using aminoplast (such as melamine-formaldehyde resin or blocked isocyanate under the conditions of curing when heated to 120°C or higher. In the conventional system in two packages polyol as one component smesi the Ute with the stapler, in the General case with isocyanate, shortly before application, the curing is carried out at ambient temperature or at elevated temperatures up to 80°C.

To achieve an acceptable viscosity solution (20-30 seconds funnel Ford No. 4 approximately at 25° (C) for conventional systems for coatings with high solids content it is necessary that the mass-average molecular weight (Mw) of film-forming polymer would be below 5000. To obtain such systems after stitching films with good properties is also necessary to srednekislye molecular weight (Mn) would have been more than about 800, and that each polymer would contain at least two reactive hydroxyl functional groups. These General principles apply to complex polyether polyols, acrylic polyols, and the urethane polyols. For priming systems following desirable properties, good adhesion, corrosion resistance and hardness. The use of urethane polyols (aliphatic) in General disadvantageous from the standpoint of cost and is rarely found in primer systems. The durability of the complete system to cover mainly provided with coating layers. It is therefore often used epoxy primer.

However, the epoxides are usually different height is Kimi molecular masses and, thus, the high viscosities. As should be clear from the discussion above, the requirements for acceptable viscosities of solutions and good film properties lead to conflicting requirements to the molecular weight, since at low viscosities of solutions of molecular weight should be low, but for a good film properties molecular weight should be high.

Many of the currently used automotive coatings and coatings used to finish the car in the repair, high performance and high solids content, are based polymer systems containing either epoxides (widely used for priming systems), or polyols based on polyesters or polyacrylates. The applicant was able to achieve benefits in terms of chemical and physical properties compared with the properties of acrylates and polyesters, such as excellent adhesion, superior hardness and superior resistance to solvents. Applicants offer advantages in terms of VOC (volatile organic compounds) compared with high molecular epoxides.

Much of the work was performed in relation to coatings containing polyurethane polyols. One method of obtaining p is lauretano polyol is the reaction of a diisocyanate or a multifunctional isocyanate with a substantial stoichiometric excess of diol. After completion of the reaction the excess diol is removed, preferably by conducting the distillation. The obvious disadvantage of this method of obtaining low molecular weight polyurethane polyols is that distillation diols inconvenient, impractical and disadvantageous from a cost perspective. U.S. patents describing obtain polyurethane polyols resulting from the use of a stoichiometric excess of diols, include: U.S. patent 4543405 authors Ambrose, et al.; issued September 24, 1985; and U.S. patent 4288577 author McShane, Jr., issued September 8, 1981.

U.S. patent No. 5155201 describes polyurethane polyols containing reaction products of n-functional polyisocyanates (n=2-5) and mainly Monomeric diols in which the hydroxyl groups are separated by three or less carbon atoms, and it is incorporated herein by reference.

U.S. patent No. 5175227 describes compositions for coatings, resistant to acid etching containing polyurethane polyols and staplers, reactive towards hydroxyl groups. Polyurethane polyols include the reaction products essentially Monomeric asymmetric diols with hydroxyl groups separated by three or less carbon atoms, and n-functional polyisocyanates (n=2-5). This patent is incorporated herein by reference.

In addition, atent U.S. No. 5130405 describes coating, resistant to acid etching, containing (1) a polyurethane polyols obtained from the symmetric 1,3-diol components and polyisocyanates, and (2) staplers, reactive towards hydroxyl groups, and it is incorporated herein by reference.

WO 96/40813 describes a film-forming composition of the polyol, polyurethane polyol, obtained from n-functional isocyanate with at least one diola or triol, or mixtures thereof and compounds containing functional groups which are reactive towards isocyanate, preferably monofunctional alcohol or thiol, and a method of obtaining such polyurethane polyols. WO 96/40813 is incorporated herein by reference.

In some of the aforementioned patents polyurethane polyols derived from α,βand/or α,γ-diols and polyisocyanates. However, it was found that polyurethane polyols obtained only from α,βand/or α,γ-diols and aromatic triisocyanate, offer extremely high viscosities, and they cannot be used for the compositions of the coatings with low VOC content, because of high viscosity will entail a high VOC content.

It would therefore be advantageous to get cheap polyol suitable for use in coatings with high solids content, to the which not only would have had the desired range of properties, but also would be quite easy to obtain. Presently discovered that polyurethane polyols derived from α,βand/or α,γ-diols and mixtures of triisocyanate with diisocyanates, where at least one of the isocyanate is an aromatic, do not have the above disadvantages.

Primers derived from data poliuretanowych polyols, find improved performance. For them unexpectedly demonstrated rapid curing at ambient temperature, improved hardness, excellent resistance to solvents and excellent adhesion to the substrate, even for metal substrates, in comparison with common primers commonly used in industry.

Summary of invention

In accordance with the present invention serves aromatic polyurethane polyol having particular advantages and suitable for use in compositions for coatings with high solids content, which in its General concept is a polyurethane polyol containing the reaction product

(A) at least one diol component selected from the group consisting of α,β-diols, α,γ-diols and mixtures thereof,

(C) at least one triisocyanate and

(C) on ENISA least one diisocyanate,

where at least one is aromatic isocyanates, and

where the molecular weight (Mn) of the polyurethane polyol is less than about 3000.

Detailed description of the invention

The composition of the aromatic polyurethane polyol in accordance with the present invention can be synthesized using either aromatic or aliphatic diisocyanates. Examples of such diisocyanates include, but are not limited to them: colorvision (TDI), available on the market under the name, e.g., MONDUR TD or MONDUR TDS from Bayer; 1,6-hexamethylenediisocyanate (HDI), available on the market under the name of, for example, DESMODUR H from Bayer; isophorondiisocyanate (IPDI), supplied to the market, for example, the firm Creanova; tetramethylcyclopentadiene (TMXDI), supplied to the market, for example, the firm Cytek; 2,2,4-trimethyl-1,6-hexamethylenediisocyanate supplied to the market, for example, the firm Creanova; diphenylmethanediisocyanate available on the market under the name of, for example, MONDUR M or MONDUR ML from Bayer; methylene (bis-4-cyclohexylidene), available on the market under the name of, for example, Desmodur W from Bayer; and biuret and uretdione data diisocyanates.

Triisocyanate that can be used for aromatic polyurethane polyol of the present invention, include both aromatic and alifaticheskii triisocyanate. Examples of such triisocyanate include, but are not limited to these: isocyanurate TDI, available on the market under the name of, for example, Desmodur IL from Bayer; adduct of trimethylolpropane (TSR) and TDI, available on the market under the name of, for example, Desmodur CB-72 from Bayer; isocyanurate HDI, available on the market under the name of, for example, Desmodur N-3300 from Bayer; isocyanurate IPDI, available on the market under the name of, for example, Desmodur Z4470S from Bayer.

Examples α,βand/or α,γ-diols that can be used in aromatic polyurethane polyol of the present invention include, but are not limited to these: 2-butyl-2-ethyl-1,3-propandiol (BEPD)supplied to the market, for example, the firm NESTE Chemicals; 2-ethyl-1,3-hexanediol (EHDO)supplied to the market, for example, the firm Dixie Chemicals; 1,2-propandiol supplied to the market, for example firm Eastman Chemicals; 1,3-butanediol supplied to the market, for example, the firm Aldrich; 2,2,4-trimethyl-1,3-pentanediol, supplied to the market, for example, the firm Neste Corporation; 1,2-hexanediol supplied to the market, for example, the firm Aldrich; 1,2-octandiol supplied to the market, for example, the firm Aldrich; 1,2-decanediol supplied to the market, for example, the firm Aldrich; and 2,2-dimethyl-1,3-propandiol, available on the market under the name NPG from company Eastman Chemicals.

Preferred diols include those that contain from 2 to 18 carbon atoms, and b is more preferably from 2 to 10 carbon atoms.

In addition, as will be shown in the examples below, the use of α,β-diols and/or α,γ-diols achieve lower viscosity at higher solids content than other dialami, such as 1,4-diol, 1,5-diol or 1,6-diol. Theyα,β-diols and/or α,γ-diols) are smaller values of molecular masses, particularly in regard to Mw, thus allowing for smaller values of polydispersity.

More preferred aromatic polyurethane polyols of the present invention differ srednekamennogo molecular weight (Mn) in the range from about 800 to about 2000, while the ratio of mass-average molecular weight (Mw) to srednekamennogo molecular weight (degree of dispersion) is in the range from about 1.1 to about 2, and HE-values are in the range of from about 165 to about 240 mg KOH/g

The components of the present invention may not necessarily react in the presence of a polyurethane catalyst. Suitable polyurethane catalysts are well known, and they can be used in commonly used amounts. The choice of a particular catalyst will be determined on the basis of a number of factors, such as specific processes used the coefficients and reaction conditions. Data and other factors well known to experts in the relevant field, who, consequently, can make the proper choice. Some of the preferred catalysts include compounds containing tin and tertiary amine, such as ORGANOMETALLIC compounds of tin and tertiary alkylamines followed.

Different types of staplers that can be used include, but are not limited to them, isocyanates, blocked isocyanates, and/or melamine and/or other staplers that have reactivity towards hydroxyl groups of the polyurethane polyols.

The coating composition of the present invention may also contain from about 1 to about 50 weight percent of the resin (binder), such as polyacrylates, polyesters, alkyd resins, phenolaldehyde resins, epoxy resins, polyethers, polyurethanes and mixtures thereof. Compositions for coatings described in this invention can be used for primers, basic coatings, surface layers and non-pigmented coating, but preferably as primers.

In the composition for coating according to the present invention optionally can contain pigments. Suitable pigments include various types of commonly used state of the art,which include, but not limited to: titanium dioxide, graphite, carbon black, zinc oxide, calcium sulfide, chromium oxide, zinc sulfide, zinc chromate, strontium chromate, barium chromate, lead chromate, lead cyanamide, siliconomas lead, yellow, Nickel titanium yellow, chromium titanium, red micaceous iron pigment, yellow micaceous iron pigment, black micaceous iron pigment, naftalie red and brown, anthraquinones, dioxazines purple, isoindoline yellow, arylene yellow and orange, ultramarine blue, phthalocyanine complexes, amaranth, chinagreen, pigments containing halogenated thioindigo, pigments and fillers, such as magnesium silicate, aluminum silicate, calcium silicate, calcium carbonate, colloidal silicon dioxide, barium sulphate and zinc phosphate.

Composition for coating of the present invention may also contain additional components such as solvents, catalysts, stabilizers, fillers, additives, modifying rheological properties, additives that increase the fluidity, alignment tools, dispersing additives, and other components, known to experts in the relevant field of technology.

The present invention also relates to compositions for coatings containing aromatic polyurethane polyol of the present invention and by the tel.

Compositions for coatings containing this aromatic polyurethane polyol of the present invention can be applied to any number of well-known substrates using any of a number of commonly used methods of application. One preferred substrate is a metal. Compositions particularly suitable in industries related to trim repair, in particular in the body shop for repair of cars and vehicles, and when finishing large vehicles such as trains, trucks, buses and airplanes. Curing of the coating can be performed in a wide range of conditions known to the person skilled in the field, despite the fact that the curing of the above-described two-component systems preferably carried out under conditions of ambient temperature, typically in the temperature range from ambient temperature to about 60°C.

Compositions particularly suitable in industries related to trim repair, in particular in the body shop for repair of cars and vehicles, and when finishing large vehicles such as trains, trucks, buses and airplanes. The preferred application of the present invention is a primer for the finish of the vehicle during the repair. When the Eden above General discussion of the present invention will be illustrated by the following specific, but non-limiting examples.

Ways

In the examples below, the viscosity Brookfield was measured at 25°C, spindle # 4 at 20 rpm. Film formation was tested in accordance with ASTM D 1640-95, Standard Test Methods for Drying, Curing, or Film Formation of Organic Coatings at Room Temperature. Adhesion and hardness tested after immersion in water for 24 hours using ASTM D 870-92, Standard Test Methods for Testing of Water resistance of Coatings Using Water Immersion. Adhesion was tested in accordance with ASTM D 3359-95, Standard Test Methods for Measuring Adhesion by Tape Test. Hardness tested in accordance with ASTM D 4366-95, Standard Test Methods for Hardness of Organic Coatings by Pendulum Damping Tests, test method B - Persoz Pendulum Hardness Test.

Examples

Synthesis of aromatic polyurethane polyol

Example 1

A 3-necked round bottom flask with a volume of 5 liters, equipped with a stirrer, a refrigerator, a heating jacket, a thermocouple with temperature controller inputs for nitrogen and for additives, download the following: to 233.1 g of 2-heptanone, 1057,7 g of 2-butyl-2-ethyl-1,3-propane diol and 2.2 g of dilaurate dibutyrate (10%solution in butyl acetate). The mixture was heated to 70°C in an atmosphere of nitrogen.

When the temperature reached 70°and stabilized in the flask over 180 minutes over the surface content was introduced following mixture: of 600.0 g of 2-heptanone, 1082,4 g Desmodur CB-72 [trifunctionally isocyanate adduct colordistance (TDI) and trimethylolpropane (TSR) (equivalent is Etna weight with 72% of non-volatile components = 328 grams/equivalent)] and 293,24 g of 2,4-colordistance (equivalent weight, with 96% of non-volatile components = 90,71 grams/equivalent). While adding this mixture, the reaction temperature was kept approximately equal to 70°C. After complete addition, the reaction temperature was kept equal to 70°even for two hours, and at the moment using infrared spectroscopy with Fourier transform FTIR has determined that no residual isocyanate remained.

The content of nonvolatile components in the resulting solution of aromatic polyurethane polyol is equal to 65.4%, the viscosity of the solution according to Brookfield equal 3680 SDR (25°S, spindle No. 4, 20 rpm), and its hydroxyl number is 174,0 (mg KOH/g).

The molecular weight of the polymer was measured by means of gel chromatography (GPC) on the device from the company Waters' Associates and polystyrene standards from the company Phenomenex. The polyurethane polyol Mn was equal 1109, Mw was equal to 1594, and the degree of dispersion D was equal 1,43.

Example 2-9

The polyurethane polyols of examples 2-9 were obtained by the method similar to what was used for the polyurethane polyol of example 1 from the components listed in table 1.

Properties of the resulting polyurethane polyols of examples 2-9 are shown below in table 2. This table also compares the results of the characterization for aromatic polyurethane polyols derived from α,β-diols or α,γ-diols, in comparison with results for other types of diols.

Examples of operational characteristics

The following examples of compositions of the primers were obtained in accordance with the following mass percentages: aromatic polyurethane polyol of 2.2%; the modified complex polyester polyacrylate 20,5%; dispersant additive of 0.7%; a substance that prevents de-lamination, 1.1 percent; commonly used solvents 15.5 percent; calcium carbonate, 21%; talc 8,5%; zinc phosphate 10%; TiO₂20%; and a thixotropic additive of 0.5%.

Example 10

The basis of the original primer was system of a binder consisting of a mixture of 90/10 commercially available modified complex polyester polyacrylate (Setlux 2152, supplied to the market by the company Akzo Nobel Resins inc.)/complex polyester. This primer composition also contained two catalyst (10%solution of triethylenediamine in isopropyl alcohol, and 18% of Zirconia in white spirits with the content of 0.9 and 0.3 mass percent, respectively). In order to assess aromatic polyurethane polyol, a complex of the polyester in the mixture was replaced by aromatic polyurethane polyol of example 1. No additional catalysts in the system was not added (dilaurate dibutylamine is the catalyst to be added together with the first curing accelerator). Fully composed song paints activated separately in two different curing accelerators; and the first curing accelerator contained hexamethylenediisocyanate (HDI) based on MDI (biuret) when the solids content of 40 mass% in butyl acetate with from 0.005 mass% to 10%-aqueous solution of dilaurate dibutylamine in a mixture of ester/aromatic solvents; and a second curing accelerator contained a mixture of 60/40 MDI (isocyanurate) on the basis of HDI/MDI (isocyanurate) based on IPDI when the solids content of 69 weight percent with a ratio of NCO:OH equal to 1.05. Each sample was diluted with a mixture solvent of ketone basis to obtain maintained what I VOC, suitable for spraying, equal 4,79 pound/gallon (575 g/l).

Example 11

Aromatic polyurethane polyols of example 2 (1.0 in EQ. BEPD/0.25 EQ. Desmodur CB-72N/0.25 EQ. IPDI) and example 1 (1.0 in EQ. BEPD/0.25 EQ. Desmodur CB-72N/0.25 EQ. TDI) were introduced in the composition of the original primer as substitutes for complex polyester with % in the calculation of the solid phase (10%as before). Composition g is Novak for the application without conducting sandblasting was made at 105%, using the first curing accelerator, and diluted to a content of VOC 4,65 pound/gallon (558 g/l)using a mixture of ketone solvents. The composition of the primers for application after conducting sandblasting was made at 105%, using a third curing accelerator is a mixture of two solvent free polyisocyanates based on aliphatic HDI, diluted to a solids 42% (wt.) using commonly used solvent mixture, and diluted to the VOC content of 4.2 lb/Gal (504 g/l), using the diluent based on the ketone solvent. On the panel was applied coating layer of the primer composition coating/non-pigmented coating, and then the panel was subjected to heat aging for 4 hours at 60°C.

For each system evaluated the adhesion and hardness on cold-rolled steel (CRS), which were treated patented commercially available protravel primer (wash primer EMCF from the company Akzo Nobel Coatings Inc.), in a simple test on immersion in water at ambient temperature.

Example 12

The evaluation was performed for the two compositions containing aromatic polyurethane polyols of example 2 and example 1, acting as the mandated is the determinant of a complex polyester (10%, as previously) in the composition of the original primer. In addition, the first composition contained Wollastocoat 10ES, and the second composition contained Wollastocoat 10AS. If the application without conducting sandblasting activation was carried out at 100 volume parts paint/50 volume parts of a curing accelerator 1 and 30 volume parts of a mixture of ketone solvents. If applying after conducting sandblasting activation was carried out at 3 volume parts paint/1 volumetric part of the curing accelerator 3+10% (vol.) a mixture of ketone solvents.

Panels made of cold-rolled steel processed commercially available protravel primer (wash primer EMCF from the company Akzo Nobel Coatings Inc.), after this was applied coating layer in the primer coating/non-pigmented coatings. The panel was subjected to heat aging for 4 hours at 60°C.

Conclusion

Above it was described only a limited number of preferred embodiments of the invention. However, a specialist in the relevant field recognized the existence of numerous substitutions, modifications and changes may be made without deviating from the essence and scope of the invention, a limited forth in the following claims.

1. A primer composition containing an aromatic polyurethane polyol containing the reaction product

(a) at least one diol component selected from the group consisting of α,β-diols, α,γ-diols and mixtures thereof,

(b) at least one triisocyanate and

(c) at least one diisocyanate,

where at least one of the isocyanate is an aromatic and

where the molecular weight Mn of the aromatic polyurethane polyol is less than about 3000,

and the finisher.

2. A primer composition according to claim 1, where α, β and/or α, γ aromatic diols polyurethane polyol selected from the group consisting of 2-butyl-2-ethyl-1,3-propane diol, 2-ethyl-1,3-hexandiol, 1,2-propane diol, 1,3-butanediol, 2,2,4-three is ethyl-1,3-pentanediol, 1,2-hexandiol, 1,2-octanediol, 1,2-decanediol and 2,2-dimethyl-1,3-propane diol.

3. A primer composition according to claim 1, where triisocyanate aromatic polyurethane polyol selected from the group consisting of isocyanurate colordistance, adduct of trimethylolpropane and colordistance, isocyanurate of hexamethylenediisocyanate and isocyanurate isophorondiisocyanate.

4. A primer composition according to claim 1, where the aromatic diisocyanate polyurethane polyol selected from the group consisting of colordistance, 1,6-hexamethylenediisocyanate, isophoronediisocyanate, tetramethylethylenediamine, 2,2,4-trimethyl-1,6-hexamethylenediisocyanate, diphenylmethanediisocyanate, methylene (bis-4-cyclohexylsulfamate), and Burlov and uretdione data diisocyanates.

5. A primer composition according to claim 1 where the crosslinker is chosen from the group consisting of isocyanates, blocked isocyanates, and melamine.

6. A primer composition according to claim 1, where the staple has a reactivity towards hydroxyl groups of the aromatic polyurethane polyol.

7. A primer composition according to claim 1, additionally containing resin.

8. A primer composition according to claim 7, where the resin is chosen from the group consisting of acrylic resins, polyesters, alkyd resins, phenolaldehyde resins, epoxy resins, simple polyester is in, polyurethanes and mixtures thereof.

9. Method of coating a substrate comprising applying to the substrate a primer composition according to claim 1.

10. Method of coating a substrate comprising applying to the substrate a primer composition according to claim 7.

11. The way of finishing the car in the repair, including the application of a primer composition according to any one of the preceding claims 1 to 8.