Method of polyurethanedi(met)acrylates production

FIELD: chemistry.

SUBSTANCE: invention concerns method of obtaining polyurethanedi(met)acrylates applicable as binders for powder coatings applied on metal substrates, plastic parts, fiber-reinforced plastic parts. Polyurethanedi(met)acrylates are obtained by interaction of diisocyanate component, diol component and hydroxy-C₂-C₄-alkyl(met)acrylate at mol ratio of x:(x-1):2, where x takes any value from 2 to 5. 1,6-hexanediisocyanate comprises 50 to 80 mol % of diisocyanate component, and one or two diisocyanates selected out of defined diisocyanate group where mol content of respective diisocyanates amount to 100 mol % comprise(s) 20 to 50 mol %, so that each diisocyanate comprises at least 10 mol % of diisocyanate component. Diol component includes not more than four different diols, and at least one linear aliphatic alpha, omega-C₂-C_12-diol comprises 20 to 100 mol % of diol component, while at least one (cyclo)aliphatic diol different from linear aliphatic alpha, omega-C₂-C_12-diols comprises 0 to 80 mol %. Each diol of the diol component comprises at least 10 mol % of diol component, and mol content or respective diols amounts to 100 mol %. Due to the absence of solvent in polyurethanedi(met)acrylate production, further cleaning of end product is not required, thus increasing process product output.

EFFECT: higher acid resistance of coating films applied and solidified with the use of powder coatings containing claimed polyurethanedi(met)acrylates.

6 cl, 15 ex, 3 tbl

The prior art to which the invention relates

The present invention relates to a method of manufacturing polyurethane(meth)acrylate, polyurethane(meth)acrylates obtained by the method according to the invention, and compositions of powder coating (powder coating), which contain polyurethane(meth)acrylate as a binder.

Description of the prior art

The polyurethane(meth)acrylates used as a binder for the production of powder coating compositions known from WO 01/25306. They are obtained by reacting at least one linear aliphatic diisocyanate, at least one aliphatic compound c, at least two functional groups capable of reacting with isocyanate groups and/or water, and at least one olefin-unsaturated compounds with a functional group capable of reacting with isocyanate groups. WO 01/25306 recommends carrying out the reaction in an organic solvent or solvent mixture(s) is(are) reactive(s) with respect to isocyanate groups. Then the polyurethane(meth)acrylate can be obtained by evaporation and/or crystallization and/or recrystallization. All the syntheses described in the section "Examples" WO 01/25306 are in methylethylketone to the to the inert solvent, followed by cooling the resulting solution at 3°C for 12 hours, from which polyurethanebased isolated in the form of precipitated solids by filtration under suction, washing and drying in vacuum.

Despite the fact that the reaction in an organic solvent, really results in is suitable for use as binders for powder coatings products, it is disadvantageous in various respects. The solvent must be completely separated from the product that you want to use as a binder for powder coating. The output decreases from cleanup.

The repetition of the examples of WO 01/25306 in the absence of organic solvent is problematic either because you need to use an excessively high melting point, leading to the risk of thermal free-radical polymerization of olefinic double bonds, or because they get products that are unsuitable as binders for powder coatings, as their melting point or melting range is too high (high) or too low (low). Excessively low melting point does not allow processing to form a powder coating: grinding, for example, becomes more difficult or impossible. An excessively high melting point, for example, are incompatible with the associated with oskouie coating processes, which include the curing process for which is listed lower the melting temperature. An excessively high melting point also often have a negative impact on the alignment of the powder coating in the molten state during the curing process.

There was a requirement to develop a production method suitable as binders for powder coatings, polyurethane(meth)acrylates, which avoids the above disadvantages.

Accordingly, according to the invention was developed process occurring in the absence of solvents and without loss of output and allows you to get polyurethane(meth)acrylates, which, even without treatment can successfully be used as binders for powder coatings.

The invention

The new method according to this invention includes a method of obtaining polyurethane(meth)acrylates, in which diisocyanate component, a diol component and hydroxy-C₂-C₄the alkyl(meth)acrylate, preferably hydroxy-C₂-C₄-alkylacrylate, react in the absence of a solvent and without subsequent action to clean up in a molar ratio x:(x-1):2, where x is any value from 2 to 5, preferably from 2 to 4, in which from 50 to 80 mol % diisocyanate component is 1,6-hexadienal, and from 20 to 50 mol % is(are) one or two diisocyanate, each of them is at least 10 mol % diisocyanate component and is selected from the group consisting of toluylene diisocyanate, diphenylmethanediisocyanate, dicyclohexylmethane, isophorondiisocyanate, trimethylhexanoate, cyclohexanebutyrate, cyclohexyldimethylamine and tetramethylethylenediamine, where the mol % of the respective diisocyanates total 100 mol %, in which the diol component comprises no more than four different diols and from 20 to 100 mole percent diol component is at least one linear aliphatic alpha, omega₂-C₁₂-diol, and 0 to 80 mol % of at least one (cyclo)aliphatic diol that is different from linear aliphatic alpha, omega₂-C₁₂-diols, where each of the diols diol component is at least 10 mole % diol component, and where the mol % of the respective diols total 100 mole %.

Detailed description of embodiments

In the method according to the invention diisocyanate component, a diol component and hydroxy-C₂-C₄the alkyl(meth)acrylate stoichiometrically react with each other in a molar ratio x mol of diisocyanate: x-1 moles of a diol: 2 mole of hydroxy-C₂-C₄the alkyl(meth)acrylate, where x is any value from 2 to 5, preferably from 2 to 4. When the values of x>5 it is often necessary to use a fusion temperature that is so high that there is a risk of free-radical polymerization during synthesis and/or derived products, which use as binders for powder coatings have excessively high points or melting ranges, for example above 120°C. moreover, it is impossible to achieve sufficient density of crosslinking in the case of powder coatings produced using as a binder, polyurethane(meth)acrylates, which were synthesized at x>5.

From 50 to 80 mol % diisocyanate component used in the method according to the invention, 1,6-hexadienal, and from 20 to 50 mol % is(are) one or two diisocyanate selected from the group consisting of toluylene diisocyanate, diphenylmethanediisocyanate, dicyclohexylmethane, isophorondiisocyanate, trimethylhexanoate, cyclohexanebutyrate, cyclohexyldimethylamine and tetramethylethylenediamine, where in the case when you choose two diisocyanate, every diisocyanate is at least 10 mol % of the diisocyanate diisocyanate component. Preferably, when the diisocyanate or two diisocyanate, the cat is who(s) is(are) generally from 20 to 50 mol % diisocyanate component, choose from dicyclohexylthiourea, isophorondiisocyanate, trimethylhexanoate, cyclohexanebutyrate, cyclohexyldimethylamine and tetramethylethylenediamine.

From 20 to 100 mol %, preferably from 80 to 100 molar %, of the diol component consisting of from one to four, preferably from one to three of the diols makes up at least one linear aliphatic alpha, omega₂-C₁₂-diol, and 0 to 80 mol %, preferably from 0 to 20 molar %of at least one (cyclo)aliphatic diol that is different from linear aliphatic alpha, omega₂-C₁₂-diols and preferably also from alpha, omega-diols, includes more than 12 carbon atoms. Each diol diol component is at least 10 mole % diol component.

Most preferably diol component is not included in any of the diols, which are different from linear aliphatic alpha, omega₂-C₁₂-diols, preferably consisted of from one to four, preferably from one to three, and in particular, only one linear aliphatic alpha, omega₂-C₁₂-diol(s).

Examples of the linear aliphatic alpha, omega₂-C₁₂diols that can be used in the diol component, VK is ucaut ethylene glycol, 1,3-propandiol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol.

Examples of (cyclo)aliphatic diols, which are different from linear aliphatic alpha, omega₂-C₁₂-diols that can be used in the diol component include the isomers of propane diol and butanediol, which differ from the isomers of propane diol and butanediol, described in the previous paragraph, as well as neopentylglycol, butylaminoethyl, isomeric cyclohexanediol, isomeric cyclohexanedimethanol, hydrogenated bisphenol a and tricyclopentadiene.

If diol component consists of several diols, diols can be used in the form of a mixture in the synthesis method according to the invention or diols comprising the diol component used in the course of the synthesis in each case individually. It is also possible to use part of the diols in the mixture, and the remaining part (s) in the form of pure diol.

Preferably, when the method according to the invention using only one hydroxy-C₂-C₄the alkyl(meth)acrylate. Examples of hydroxy-C₂-C₄the alkyl(meth)acrylates are hydroxyethyl(meth)acrylate, one of the isomeric hydroxypropyl(meth)acrylate or one of the isomeric hydroxybutyl(meth)acrylates; in each case, it is preferable acrylate connection.

The way is according to the invention, the diisocyanates diisocyanates component, diol or diols diol component and hydroxy-C₂-C₄the alkyl(meth)acrylate to react essentially to each other, i.e. in the absence of solvent. In this process, the reagents can react with each other all at once or in two or more stages of the synthesis. When the synthesis is carried out in many stages, the reagents can be added in the most diverse manner, for example also in a row or alternating way. For example, the diisocyanates diisocyanates component may initially react with hydroxy-C₂-C₄the alkyl(meth)acrylate, and then diola or dialami diol component or first diola or dialami diol component, and then with hydroxy-C₂-C₄the alkyl(meth)acrylate. However, the diol component can also be divided, for example, into two or more parts or individual diols, for example, so that the diisocyanate reacted first with a part of the diol component to posleduushie reaction with hydroxy-C₂-C₄the alkyl(meth)acrylate, and at the end, for example, with the remaining part of the diol component. While equally diisocyanate component can, for example, also be divided into two or more parts or individual diisocyanates, for example, so that hydroxycobalamin components are first reacted with a part diisocyanate component, and p is on the end, for example, with the rest diisocyanate component. In each case, the individual reagents can be added entirely or two or more portions.

The reaction is exothermic and proceeds at a temperature above the melting temperature of the reaction mixture, but below the temperature which leads to free-radical polymerization of the double bonds of (meth)acrylate.

The reaction temperature is, for example, from 60 to 120°C maximum. The rate of addition or the number of added reagents are determined respectively on the basis of the degree of ekzotermicheskie and liquid (molten), the reaction mixture can be kept within the desired temperature range by heating or cooling.

After completion of the reaction and cooling of the reaction mixture get solid polyurethane(meth)acrylates with the calculated molar masses in the range from 628 or higher, e.g. up to 2000. Polyurethane(meth)acrylates take the form of a mixture, characterized by a molecular weight distribution. However, polyurethane(meth)acrylates do not require processing, and can directly be used as binders for powder coatings. Their melting points are, in particular, in the range from 80 to 120°C.; generally speaking, the melting temperature are not clear melting points, novesta this represents the upper limit of the melting ranges of the width, for example, from 30 to 90°C.

Polyurethane(meth)acrylates can be used in powder coatings, not only as the sole binder or as a main binder, comprising at least 50 wt.% the solid content of the resin, but also in smaller portions as sovetuyesh. It is a remarkable high resistance of coating films applied and hardened from powder coatings, in relation to acids.

Powder coating manufactured using polyurethane(meth)acrylates obtained according to the invention as binders for powder coatings may include powder coating, cured solely by free-radical polymerization of the double bonds of olefins, which otverzhdajutsja thermally or by irradiation with high energy radiation, in particular UV-irradiation. They, however, can also include powder coating dual-cure, which additionally otverzhdajutsja through an additional mechanism of cross-linking caused in most cases by the action of temperature.

Depending on the nature of powder coatings, the composition of the solid resins may also include in addition to obtained according to the invention, polyurethane(meth)acrylate additional binder and/or cross-linking reagents. Complete the performance communications binders and/or crosslinking reagents can be cured in these coatings thermally and/or by exposure to high energy radiation.

While thermally curable powder coatings contain initiators of free-radical polymerization, splitting under the action of temperature, curing by means of UV irradiation powder coatings contain photoinitiator.

Depending on the selected curing conditions (purely thermal curing or a combination of curing under the action of UV radiation and temperature) powder coating dual-cure may contain initiators of free-radical polymerization, splitting under the action of temperature, or photoinitiator.

Examples of initiators of free-radical polymerization, splitting under the action of temperature, are azo compounds, peroxide compounds and initiators, fissile C-C bond.

Examples of photoinitiators are benzoin and its derivatives, acetophenone and its derivatives such as 2,2-diacetoxyscirpenol, benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone, 1-benzoylecognine, organophosphorus compounds, such as acylphosphatase.

Initiators for curing by free radical polymerization using, for example, in proportions of from 0.1 to 7 wt.%, preferably from 0.5 to 5 wt.%, relative to the total solid content of the resin and initiator. Initiate the s can be used individually or in combination.

Besides the already stated initiators powder coating can contain additional conventional additives for coatings, for example, inhibitors, catalysts, levelling agents, degassing agents, moisturizing agents, reagents that prevent the formation of surface defects, antioxidants and light stabilizers. Additives are used in conventional amounts known to the skilled in this technical field specialist.

Powder coating can also contain transparent pigments, the pigments that give color and/or special effects, and/or fillers, for example, with a ratio of the weight content of the pigment plus filler: solid resin in the range of from 0:1 to 2:1. Examples of inorganic or organic pigments that give color, are titanium dioxide, iron oxide pigments, carbon black, azo pigments, phthalocyanine pigments, chinaredorbit or pyrrolopyrazole pigments. Examples of pigments that give special effects are metal pigments, for example, made of aluminum, copper or other metals, interference pigments, such as metal pigments coated with metal oxides, for example, coated titanium dioxide or mixed oxides of aluminum, coated mica, such as, for example, coated titanium dioxide mica. An example is the mi of suitable fillers are silicon dioxide, aluminum silicate, barium sulfate, calcium carbonate and talc.

Powder coatings can be prepared using conventional methods known to the skilled in this technical field specialist, in particular, for example, by extrusion powder coating, which has already been completely made by dry blending all of the required components, in the form of a viscous melt, cooling the melt, rough grinding, fine grinding, and then split on the sieves to obtain the desired fineness of the grains, for example, to obtain average particle size from 20 to 90 μm.

Powder coating can be used for any desired purpose associated with industrial coatings and apply using conventional methods, preferably by spraying. Bases that can be considered are, in particular, not only the metallic base, but also plastic parts, for example, also reinforced fiber plastic parts. Examples are automobile bodies and parts of bodies, such as the valve body.

Powder coatings preferably include compositions non-pigmented powder coatings, which are used for making the outer layer of non-pigmented powder coatings for imparting color and/or special event the e effects of the primary coating layer. For example, to give the color and/or special effects, the main layer of the coating can be applied to automotive body, provided traditional primer, and, if desired, otvetit, and after that you can apply and cure non-pigmented powder coating composition non-pigmented powder coatings. If the primary coating layer is not overiden before applying the non-pigmented powder coatings, powder non-pigmented coating is applied by a process of "wet on wet".

The method used for applying powder coatings may, for example, consist of applying a first powder coating on an individual basis and melting by heating the applied powder coating to a temperature above the melting temperature, for example, in the range from 80 to 150°C. After melting by heat, for example, when convective and/or radiative heating, and if desired, provide the received phase possible alignment curing may occur when exposed to radiation of high energy and/or for the purpose of thermal energy. As the high energy emission is possible to use UV-radiation or radiation of the electron beam. Preferred is UV radiation.

The following examples illustrate the invention. The abbreviation “pbw” so, it is used to lower means weight part.

EXAMPLES

Examples c 1a through 1i (getting polyurethanecoated for comparative purposes)

Polyurethaneacrylate was obtained by reacting 1,6-exanguination with dialami and hydroxyethylacrylate in accordance with the following General method of synthesis:

First in a 2-liter chetyrehmetrovuyu flask equipped with stirrer, thermometer and column, introduced 1,6-hexadienal (HDI) was added 0.1 wt.% methylhydroquinone and 0.01 wt.% dilaurate dibutylamine, in each case relative to the initially introduced amount of HDI. The reaction mixture was heated to 60°C. Then they dosaged hydroxyethylacrylate in such a way that the temperature did not exceed 80°C. the Reaction mixture was stirred at 80°C until then, until reaching theoretical NCO content. Once theoretical NCO content was reached, one after another was added diols And, in each case in such a way that the temperature was maintained between 75 to 120°C. In each case, subsequent diol was not added until, until reaching theoretical NCO content. The reaction mixture was stirred at 120°C until then, until reaching the total absence of free isocyanate. The hot melt was poured and he was allowed to cool.

The behavior of the resulting polyurethanecoated melting b is lo investigated using DSC (differential scanning calorimetry, the heating rate 10 K/min).

Table 1 shows comparative examples 1a through 1i. Table notes on the ingredients in any molar ratios reacted with each other, and the result that was achieved. In particular, the final temperature of the melting process measured by DSC indicated in °C.

Examples c 2a through 2f (getting polyurethanecoated according to the invention)

Polyurethaneacrylate was obtained by reacting 1,6-exanguination, additional diisocyanate, diol component and hydroxy-C₂-C₄-alkylacrylate in accordance with the following General method of synthesis.

First in a 2-liter chetyrehmetrovuyu flask equipped with stirrer, thermometer and column, introduced 1,6-hexadienal (HDI), as well as additional diisocyanate was added 0.1 wt.% methylhydroquinone and 0.01 wt.% dilaurate dibutylamine, in each case relative to the initially introduced amount of the diisocyanate. The reaction mixture was heated to 60°C. Then hydroxyethylacrylate were dosed out in such a way that the temperature did not exceed 80°C. the Reaction mixture was stirred at 80°C until then, until reaching theoretical with the actual content of the NCO. Once theoretical NCO content was reached, one after another was added diols and, if desired, in each case in such a way that the temperature was maintained between 75 to 120°C. In each case, subsequent diol was not added until, until reaching theoretical NCO content. The reaction mixture was stirred at 120°C until then, until reaching the total absence of free isocyanate. The hot melt was poured and he was allowed to cool.

The behavior of the resulting polyurethanecoated melting was investigated using DSC (heating rate 10 K/min).

Examples 2a through 2f are shown in table 2. The table shows the ingredients in any molar ratios reacted with each other and the result that was achieved. In particular, the final temperature of the melting process measured by DSC indicated in °C.

Examples 3a through 3p

The powder coating composition obtained was applied and utverjdali using polyurethanecoated binders of comparative examples 1a through 1i and using polyurethanecoated binders of examples 2a through 2f, using the following basic rules.

Fragmented mixture of the following components pre-mixed and extrudible:

96,5 weight. parts of one of polyurethanecoated of examples 1a through 1i or one of polyurethanecoated of examples 2a through 2f,

1 weight. part of Irgacure®2959 (photoinitiator from the company Ciba),

0,5 weight. part Powdermate®486 CFL (leveling agent from company Troy Chemical Company,

1 weight. part of Tinuvin®144 (HALS light from the company Ciba), and

1 weight. part of Tinuvin®405 (UV-absorber from the company Ciba),

to obtain the composition of the non-pigmented powder coatings in the traditional way after cooling, crushing, grinding and sifting.

The respective powders of the e non-pigmented coating was sprayed to a layer thickness of 80 μm in each case on steel sheets, covered with a commercially available paint done by way of deposition, the filler and the main floor (where the air bubbles are removed)were subjected to melt for 10 min at 140°C (oven temperature) and utverjdali by UV radiation corresponding to the radiation intensity of 500 mW/cm²and the dose of 800 MJ/cm². The obtained coatings was studied with respect to their resistance to acids. In this purpose, 50 μl of 36% sulfuric acid was administered at 65°C on the paint film for 30 minutes at intervals of one minute (score: the destruction of the film after X (from 0 to 30 minutes). The results are shown in table 3.

It turned out that non-pigmented powder coatings made on the basis of polyurethanecoated binders of examples 2a through 2f are more resistant to acids than non-pigmented powder coatings made on the basis of polyurethanecoated binders of examples 1A through 1i.

1. The method of obtaining polyurethane(meth)acrylates, including interaction diisocyanate components the NTA, diol component and hydroxy-C₂-C₄the alkyl(meth)acrylate in the absence of a solvent and without subsequent action to clean up in a molar ratio x:(x-1):2, where x is any value from 2 to 5, in which from 50 to 80 mol.% diisocyanate component is 1,6-hexadienal, and from 20 to 50 mol.% is(are) one or two diisocyanate, and each is at least 10 mol.% diisocyanate component and selected from the group consisting of toluylene diisocyanate, diphenylmethanediisocyanate, dicyclohexylmethane, isophorondiisocyanate, trimethylhexanoate, cyclohexanebutyrate, cyclohexyldimethylamine and tetramethylaniline diisocyanate, where mol.% the corresponding diisocyanates are in the amount of 100 mol.%, in which the diol component comprises no more than four different diols and from 20 to 100 mol.% diol component is at least one linear aliphatic alpha, omega₂-C₁₂-diol, and 0 to 80 mol.% is at least one (cyclo)aliphatic diol that is different from linear aliphatic alpha, omega₂-C₁₂-diols, in which each diol diol component is at least 10 mol.% in the diol component, and where the mol.% the corresponding diols are in the amount of 100 mol.%.

2. The method according to the .1, in which 80 to 100 mol.% diol component is at least one linear aliphatic alpha, omega₂-C₁₂-diol, and 0 to 20 mol.% is at least one (cyclo)aliphatic diol that is different from linear aliphatic alpha, omega₂-C₁₂-diols.

3. The method according to claim 1, in which the diol component consists of from one to four linear aliphatic alpha, omega₂-C₁₂-diols.

4. The method according to claim 1, in which the diol component consists of one linear aliphatic alpha, omega₂-C₁₂-diol.

5. Polyurethane(meth)acrylates obtained according to any of the preceding paragraphs.

6. Composition of powder coatings containing polyurethane(meth)acrylates obtained according to the method according to any one of claims 1 to 4, as a binder.