MXPA01002333A - Powder slurry composition containing particulate carbamate functional compounds - Google Patents

Abstract

The invention provides a powder slurry composition having a particulate component (a) dispersed in a liquid component (b). Component (a) comprises a solid or particulate compound (i) of the formula R(X)y having Cn symmetry wherein i(n)=2 or higher and a Tg³30°C, wherein X is a carbamate functional group and y³2.

Description

PASTE POWDER COMPOSITIONS. THAT CONTAIN COMPOUNDS PARTICLE 7 TWO CARBAMATE FUNCTIONS Field of the Invention The present invention relates to powdered paste compositions, containing solid, particulate, carbamate functional compounds. The invention provides a powdery paste composition, comprising a particulate component (a) dispersed in a liquid component (b), in which the compound (a) is of the formula R (X) yy has symmetry Cn / where n = 2 or greater, and a glass transition temperature, Tg > 30 ° C, where X is a functional group of carbamate e and > 2.

BACKGROUND OF THE INVENTION Powder paste compositions have been used to provide a variety of advantages in the coating of articles. Powder paste compositions typically include a first component, which is in the form of solid particles, and a second component, which is liquid. The first component is dispersed in the second component to provide an aqueous paste, which can be applied using conventional spraying equipment and techniques.

Powder compositions for aqueous paste provide the advantages of powder coating compositions, with the ease of application of traditional solvent-borne coatings. As a result, powdered paste compositions have the potential for environmental and / or financial advantages. However, powdered paste compositions can present commitments in manufacturing, performance and / or application. Traditional powdered paste compositions often use systems of acid and epoxy compounds. Such systems can sacrifice scratch resistance and deterioration, in order to obtain acceptable water resistance, splinter resistance and chemical resistance. The nature of the powder coating composition used in the powdery pulp composition requires the use of initial temperatures above the Tg of the powdery resin, followed by temperatures sufficient to effect entanglement. Thus, high healing programs are often required. It will be appreciated that with respect to application and energy costs, the use of powdery paste compositions having lower Tg resins is encouraged. The use of lower Tg resins facilitates improved appearance, faster flow and lower healing temperatures. However, storage and manufacturing problems can result when powdered paste compositions, which have minor Tg resins, are used. Manufacturing is particularly challenging, especially with acid epoxy compound systems. The separation, precipitation and / or agglomeration of the particulate solid component, during storage can also be observed. The lower film adhesion and / or cracking of the applied powder film during curing is sometimes observed, in particular when the powder is applied onto a previously applied coating. These negative performance characteristics can be aggravated by the formation of larger films and storage stability. Finally, the finished films, obtained from the powdered paste compositions, may exhibit a variable gloss and / or lower performance characteristics, in particular when balancing the scratch resistance and deterioration against water resistance, chipping resistance and resistance to chemical products. It is often difficult to achieve an acceptable balance of properties between these characteristics, especially with traditional epoxy / powder paste compound systems. Thus, it is convenient to provide improved powder paste compositions, in which the above disadvantages are either eliminated or reduced to a minimum. The attempts of the prior art so far have not been successful. It is expected that the use of one or more particulate carbamate functional resins will provide powdered paste compositions having an advantageous balance of properties.

SUMMARY OF THE INVENTION The invention provides a powdery paste composition, having a particulate component (a), dispersed in a liquid component (b). Component (a) comprises a compound (i), solid or particulate, of the formula R (X) y, and having a symmetry C n, where n = 2 or more and a T g > 30 ° C, where X is a functional group of carbamate e and > 2. One or both of component (a) and component (b) will comprise at least one interlacing compound (ii). i? INIÍ ^ ttmtmW * -i? * Í? I Detailed Description of the Invention The powder composition of the invention requires two components, a first component (a) in solid or particulate form, which is dispersed in a liquid component (b). The first component (a) comprises a compound (i) in particles, of the formula R (X) y, where X is a carbamate functional group, y = 2 or greater. It is necessary, for the practice of the invention, that the compound (a) have a symmetry Cn, where n = 2 or greater. The compound (i) of the invention is particularly suitable for use in powder coating compositions. While not wishing to be bound by any particular theory, the particular advantages of compound (i) are believed to be due, in part, to the required symmetry of Cn, where n is 2 or greater. The compound (i) of the invention preferably has a molecular weight of 350 to 1900 and, more preferably, of 460 to 900. The equivalent weight per carbamate functional group can vary from 175 to 450 and preferably from 175 to 350. The compound (i) is normally a solid at 25 ° C, the term "solid" refers to a substance of defined configuration and a relatively large density, low internal enthalpy and great cohesion of these molecules. Grant & Hackh 's Chemi cal Di cti onary, Fifth Edi tion McGraw-Hill, Irc. pg 541. In the formula R (X) y, R is a polyvalent symmetric linking group 5, X is a functional group of carbamate e and is 2 or greater. Thus, compound (a) is a functional carbamate compound having at least two carbamate groups. Preferably, the compound (a) will have from 2 to 6 carbamate groups, ie, and is a number from 2 to 6, and, Most preferably, compound (a) will have 2 or 3 carbamate groups, ie, y is 2 or 3. R (X) and must have a particular molecular symmetry, ie, the symmetry Cn ,, where n = 2 or older. As used here, a molecule with symmetry means that certain parts of the molecule can be exchanged, through an operation of symmetry, with others, without altering the identity or orientation of the molecule. The symmetry operations are defined geometrically as the ways of exchanging the parts equivalents of a molecule. However, such operations are symmetry operations if, and only if, the appearance of the molecule is exactly the same with respect to the view before and after the symmetry operation. Thus, the term "symmetric", as used herein, refers to a molecule which looks almost identical in relation to the views before and after the symmetry operation. In other words, "the molecule [a] has an element of symmetry if the application of the operation generated by the element leaves the molecule in an indistinguishable state". Molecular 5 Symmetry and Group Theory, Alan Vincent, Wiley & Sons, NY. 1977, reprinted in 1981, page 21, incorporated herein by reference. The present application relates only to the operations of appropriate rotation symmetry. Rotation The appropriate, also referred to as "Cn", refers to a simple rotation about an axis, which passes through the molecule through an angle of 2 p / n or an angle of 360 ° / n. A molecule is said to have a symmetry element Cn if, after undergoing an appropriate rotation operation, Cn, the appearance is indistinguishable from the appearance before undergoing the appropriate rotation operation Cn, independently of the conformational isomers. Put another way, a molecule has an element of symmetry, in this case CP, when one or more of its isomers is conformation possess that element of symmetry. The element of greater symmetry, which belongs to any isomer of conformation of the molecule, is assigned to this molecule. ÉmMiM * «iMi !} ^^ '"" * -' J-- * *. > -a «~ *? a? ~ t .. < •, -4?, Go, .-. Wí ...? , "" "" 'For example, the two most common conformational isomers They are the chairs which have an e e of rotation C3 and the can conformation, which have their own axis of rotation C2. As a result, cyclohexane can be defined as a proper axis of molecular rotation C3 (Cn where n = 3), without having to define its conformation. Similarly, hexane, with the freedom of movement around its many simple links, can exist in a large number of configurations, such as: One of the hexane conformational isomers (shown below) has a self-rotation e C2. Therefore, the hexane can be said to possess an element of molecular symmetry C (where n = 2): c-.

While it can be seen that all molecules have symmetry Cn, where n is 1, the present application only relates to the groups T that also have symmetry Cn, where n is 2 or more. R can be alkyl, cycloalkyl and / or a structure containing an aromatic group, having the required symmetry Cr,. R may also comprise additional functional groups, as long as the symmetry of R is maintained. For example, R may comprise functional groups including single, double and / or triple bonds, with atoms such as C, H, S, O, N and mixtures thereof. Illustrative examples of additional functional groups include ureas, ethers, esters, carbonates and the like. In the absence of additional functional groups, examples of illustrative R groups include C4H8 and CeH2. Other illustrative examples of the R groups are: X. .X where "X" marks the location of a carbamate group. Examples of R groups, which comprise additional functional groups include ureas, such as: O R1 - NCN - R2 I I R 'R' ethers, such as -R1-O-R2-, and linear carbonates, such as O R1-OCO-R2 where R1 and R2 are identical and are selected from the group consisting of alkyl or cycloalkyl groups, having at least four carbons, and R 'and R "are identical and represent H or C? -C4 alkyl. will appreciate that in each case, R1 and R2 are linked to the carbamate groups X. R1 and R2 may have, but is not required to have, symmetry Cn, as long as R (X) y, has the symmetry Cn requeriaa, where n is 2 or greater Preferably, R1 and R2 include the C4H8 groups and A particularly preferred group Another example of a compound (i) is 0 0 0 0 H2NC0C? H, - (OCC5H] 0) n - R '- (0C5H? 0C0) n - CH40CNH2 where R 4 can be selected from the group consisting of alkyl, cycloalkyl and structures containing aromatic groups. Preferably, R will comprise a C2-Ci? or a cycloalkyl group. Examples of preferred R groups are hexane, butane and 1,4-dimethylcyclohexane. More preferably, R will be butane or hexane. The carbamate group X can be a primary or secondary carbamate, where all the X's are identical.

When the carbamate group X is a secondary group, that is, O II -OCNRiH then Ri may be a C 1 - alkyl group, with the methyl and n-butyl groups being preferred. More preferably, X will be a primary carbamate group. The compound (i) can be obtained by several methods. A preferred method for obtaining a compound (a), having the formula R (X) y, involves the reaction of a compound R (Y) n with a compound Z, where R is as described above, and Y is a functional group which can be converted into a carbamate group in one or more stages, n is two or more, and Z is a compound reactive with Y. This method can be seen as the transformation of functionality Y into the carbamate functionality in one or more stages of reaction. For example, in some reaction schemes, as described below, the reaction product of R (Y) n + Z, can be subsequently reacted with Z ', to obtain R (X) y. In other reaction schemes, the reaction product of [[R (Y) n + Z] + Z '] will react with Z ". Multistage reactions, which use Z' '', etc., are within the scope of The invention Suitable functional groups for use as Y include hydroxyl groups, alkene groups, functionality Cyclic carbonate, epoxy groups, isocyanate functionality, aminoplast functionality and halides. Generally, Y will be selected from the group consisting of hydroxyl groups, cyclic carbonate functionality, epoxy groups, isocyanate functionality, and halides. Preferred groups Y are hydroxyl, isocyanate and cyclic carbonate functionality. Hydroxyl groups are most preferred for use as Y. Z can be a compound which can react with compound Y to produce a carbamate group or a group that can be converted to a carbamate by subsequent reaction steps. Alternatively, compound Z can be a compound having the formula ZL-Q, where ZL is a linking group that is reactive with compound Y, and Q is a carbamate group or a group that can be converted to a carbamate group. It will be appreciated that the phrase "group convertible to a carbamate group" refers to those groups, as discussed below,. as the precursors of a carbamate group and / or are as discussed in the journal article of P. Adams and F. Barron, "Carbamic Acid Esters", Chemical Review, v 65, 1965. Examples of Z and / or Z1 , Z "and the like, are primary amines, secondary amines, ammonia, phosgene, isocyanates, peroxides, metal salts of hydroxy carbamates, carbon dioxide, hydroxycarbamates and mixtures thereof, eg, a compound R (Y) n / in which Y is a cyclic carbonate group (for example the reaction product of an epoxy with carbon dioxide) can be converted into a carbamate group by the reaction of a primary or secondary amine, or ammonia, i.e. , Z. It will be appreciated that this reaction scheme further illustrates how Y can be an epoxy group, where Z is carbon dioxide and Z ' is a primary or secondary amine, or ammonia. A compound R (Y) n, where Y is a carbon-carbon double bond,. can be converted into an epoxy, following known techniques (for example the reaction with peroxides), then transformed into a carbamate, as showed before. A compound R (Y) n, where Y is OH, can be converted to a carbonate by reaction with phosgene, followed by reaction with a primary or secondary amine or ammonia. Alternatively, when Y is a Hydroxy group, R (Y) n can react with a monofunctional isocyanate (Z). When Y is an isocyanate group, it can then be reacted with a carbamate which can react with the isocyanate (for example, the hydroxyethyl carbamate, hydroxypropyl carbamate, aminoethyl carbamate). In this case, the Carbamate that can react with the isocyanate is of the formula ZL-Q. When Y is a halide group (for example chlorine), R (Y) n can react with a Z, which is a metal al (for example sodium, lithium, etc.) of a hydroxy carbamate. An R with carboxylic acid groups can be converted to an acid anhydride (e.g., the reaction with acetic anhydride) to generate an acid anhydride which can then be reacted with a hydroxy carbamate or a carbamate of each. When Y is an aminoplast group (for example a carbamate group that has been reacted with an aldehyde or urea), Y can react with a carbamate functional group: vmyl, epoxy, cyclic carbonate, hydroxy or a carboxylic acid group, (ie ZQ, in which ZL is the carbamate group and Q is the vinyl, epoxy, cyclic carbonate, hydroxy or carboxylic acid group) and then converted to a carbamate, as described above. It will be appreciated that the foregoing is illustrative only and that other suitable compounds, such as those discussed above, can be used to obtain a compound (i) of the invention, having the formula R (X) y. The compound (i) of the invention will be processed, typically, in one or more solid masses, for example in sheets, rolls or drops, by accepted manufacturing techniques of powdered compounds. After solidifying, the mass is broken into particles with the desired size and configuration. This size and configuration of the particles of the compound are dependent on the considerations of handling, process and equipment. Preferably, the compound (i) will have the configuration of flat pieces or discs having regular or irregular dimensions. Particles that have an average particle size of 2.54 to 7.62 will be preferred, with an average particle size from 1 miera to 2.54 cm, being more preferred. The particle size, as used herein, refers to the average diameter of an object having irregular edges, which can be determined with known test methods. It will be appreciated that the particulate component (a) is preferably a compound (i) comprising a powder coating. Before dispersion in the component (b) liquid, component (a) must have an average size of particles from 0.1 to 100 microns. A preferred average particle size of component (a), at this time, varies from 3 to 60 microns. An average particle size of 30 to 45 microns is most preferred. Traditional extrusion and grinding processes can be used to obtain the particulate component (a) within these ranges.

? ^ D &ie. * Compound (i) may initially have an average particle size inside or outside this range, which results from known powder compound manufacturing techniques. The first solid particulate component (a), in the mixture with the liquid component (b) will typically be treated subsequently to reduce the above particle sizes to those more convenient for a powder paste composition. Once in combination with component (b), the powder composition can be subjected to a particle size reduction treatment, such as wet grinding, microfluidization, cavitation or other low temperature, high cut techniques. , known to experts in the field. Thus, the particle size of the powder composition of the invention, after a reduction treatment of this particle size, is typically from 0.1 to 20 microns, more preferably from 0.1 to 15 microns and especially preferred will be a size of average particles of 0.1 to 12 microns. The component (a) can be obtained according to conventional techniques and methods. The compositions of the invention are advantageous, because the compound (i) allows the use of higher process temperatures.

Also, during the preparation of a solid particulate component (a) or subsequent to it, pigments pigment dispersions, modifiers, dispersion aids, regulators, flow modifiers, fillers and / or additives, can optionally be added, as desired . The liquid component (b) can be one or more liquids or solvents, suitable for the dispersion of the particulate compound (a). Examples of suitable liquids or solvents include water, water soluble solvents and organic solvents and mixtures thereof. Illustrative water soluble solvents are alcohols. Examples of illustrative water soluble solvents and / or organic solvents are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methanol, ethanol, isopropanol, n-butanol, sec. -butanol, tere. -butanol, dimethylformamide, etc. Preferred liquids for the above use are water, alcohols and mixtures thereof. A more preferred liquid component (b) is water. These solvents will typically be used in amounts from 0 to 10, based on the total weight of the powder, and preferably from 0 to 1.0%. The weight ratio of component (a) and component (b) is usually from 90:10 to 50:50, preferably from 75:25 to 60:40, in terms of the solid component. The powdery paste composition of the invention may further comprise additional optional components, and R "* '* ag'a ^ jsü such as one or more solvents or additives, such as pigments, fillers, catalysts, corrosion inhibitors, modifiers, dispersants, flow additives, and mixtures thereof. These materials can be incorporated into component (a), component (b), or mixtures thereof. For the preparation of the powder composition of the invention, the required and optional components can be combined in an optional order and mixed either by conventional processes. The component (b) can be mixed with the component (a) and a pigment and, if necessary, in addition to other optional components. Alternatively, the pigment can be mixed with the component (b) to form a pigment paste, which is then mixed with a mixture of the component (a) and the component (b). A grinding operation can follow such a mixture. A preferred method of manufacture is disclosed in U.S. Patent No. 5,379,947, which is incorporated herein by reference. The powder composition of the invention has an advantageously low volatile organic content as a result of the unexpected benefits of the components of the invention. The powder composition of the invention can be applied by spraying or electrostatic deposition and is useful in applications such as a basecoat as well as a topcoat. It is expected that the compositions ^. ... "? ^^ - «* ¿resulting fra-í-gi-¿^ ^ ^ of coating form soft films with advantageous performance properties. One or both of components (a) and (b) will comprise an entanglement agent (ii) reactive with the particular compound (i). The crosslinking agent (ii) may be in liquid or solid form at the time of incorporation into component (a), component (b), or mixtures thereof. The use of the interlacing agent (ii) in liquid form and incorporated in the liquid component (b) is the most preferred. Illustrative examples of the crosslinking agent (ii) include one or more compounds having a plurality of functional groups, which are reactive with the compound (a). Suitable reactive groups include the active groups of methylol or methylalkoxy in the aminoplast entanglement agents or in other compounds, such as the phenol / formaldehyde adducts, acrylamide groups, isocyanate groups, siloxane groups, cyclic carbonate groups and groups of anhydride. Examples of this at least one intermediate compound (ii) include the melamine-formaldehyde compound (including monomeric or polymeric melamine compounds, and partially or fully alkylated melamine resins), urea resins (eg, methylol-ureas) , such as urea-formaldehyde resin, alkoxy ureas, such as butylated urea-formaldehyde resin), polymers having acrylamide groups, polymers having methylol or alkoxymethyl groups, polyanhydrides (for example polysuccinic anhydride) and polysiloxanes (for example the trimethoxy siloxane). Low monomeric and / or oligomeric aminoplast resins, such as melamine-formaldehyde or urea-formaldehyde resins are especially preferred. The ratio of equivalents of the compound (a) to the equivalents of the crosslinking agent (ii) is from about 0.5: 1.0 (a: b) to 1.5: 1.0, preferably from about 0.8: 1.0 to 1.2: 1.0. The powder paste compositions of the invention can be applied by spraying or electrostatic deposition and are useful in both the basecoat and the topcoat applications. It is expected that the resulting coating compositions form films that have an acceptable appearance with advantageous performance properties. Powder paste compositions of the invention can be applied to a variety of substrates for use in various end-use applications, such as in automobiles, furniture, industry, lawn and garden equipment, electrical equipment and the like.

Suitable substrates include metal, plastic, wood, ceramics, composites and their mixtures. Metal and / or plastic substrates are preferred. The substrates will preferably be cleaned prior to the application of the powder coating. The substrates can be pre-treated, optionally, with phosphate, chromium and similar treatment methods, to improve adhesion and / or appearance. It will be appreciated that the selection of the previous treatment is dependent on the desired substrate and the application of the final use. After application, the coated part is subjected to a curing program, sufficient to effect the flow and healing. As used herein, the "cure program" refers to the time / temperature ratio required to effect complete cure of a thermoset powder coating. Typical curing programs for the powder coatings of the invention involve parts with temperatures of 121 to 204 ° C and with a time of 10 to 30 minutes. The preferred curing programs are at a temperature of 121 to 204 ° C and a time of 10 to 20 minutes. The invention will be further described in the following non-limiting examples.

A mixture of 157.7 parts of 1,6-hexanediol, 400 parts of methyl carbamate and 655.4 parts of toluene was heated to reflux at about 114-120 ° C. Then 3.6 parts of titanium (IV) isopropoxide were added and the resulting methanol was removed from the system. Upon completion of the reaction, 85 parts of deionized water were added and the dicarbamate was isolated by vacuum distillation, to provide a colorless solid product.

Example 2 Prophetic preparation of a powdery paste composition, according to the invention Three hundred grams of the compound, obtained in the Example 1, they were ground in an ACM mill to an average particle size of 25-35 microns and placed separately. One gram of Abex EP-1101 was added to 100 grams of Cymel 3032 and mixed for 5 minutes with a standard mixing blade. A stainless steel container, with a Cowles mixing blade, was charged with 200 grams of water. Keeping the speed low, the following products were added, in 1 a surfactant, commercially available from Rhodia, a hexametoxymethyl-melamine, commercially available from Cytec. order: 5 grams of Disprersß * AYD W-223, 0.1 gram of Triton X1004 2.5 grams of propylene glycol and 3 grams of Acrysol RM-8W5. The speed of the mixer was increased to 4-500 rpm, for 5 minutes, before the addition of 132.5 grams of the milled resin. The vessel was allowed to mix for 10 minutes. Next, 43 grams of Cymel 303 premixed previously were added, followed by 7 grams of Nacure 52256 and 110 grams of water. The vessel was mixed for 10 minutes, after which the Cowles blade was replaced for a medium disc mixing blade. A sufficiently small ceramic medium (1.1 to 1.4 mm) was added to the vessel to a volume equal to 50% of the mixture. The temperature of the mixture was maintained at 18-23 ° C and stirred at 1200 rpm. The particle size was monitored over time to obtain a final average particle size of 4 to 5 micas. The disk was removed and the medium was filtered and separated using a 55 micron nylon filter. The viscosity was adjusted to 35-45"of a Ford cup # 4, the aqueous paste was sprayed from a standard siphon spray gun, over a 3 a dispersant, commercially available from Daniel Products. a nonionic surfactant, commercially available from Union Carbide. a thickening agent, commercially available from Rohm & Haas. 5 a sulfonic acid catalyst, commercially available from King Industries. base coating, which carries water, evaporated by heat, but not cured, allowing the coating for 5 minutes at room temperature and then annealing for 20 to 30 minutes at 132 ° C.

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Claims (11)

1. CLAIMS 1. A powder coating composition, which comprises: (a) a particulate component, which includes (i) a carbamate functional compound, of the formula R (X) y, and having a Cn symmetry , where n = 2 or greater, and a glass transition temperature of > 30 ° C, in which X is a functional group of carbamate e and > 2, dispersed in (b) a liquid component.
2. 2. The powder pulp coating composition according to claim 1, wherein R has a molecular weight between 50 and 165.
3. 3. The powder coating composition according to claim 1, wherein y is 2 or 34.
4. The powder coating composition according to claim 1, wherein n is 2.
5. 5. The powder coating composition according to claim 1, wherein R is selected from the group consisting of alkyl groups, having a Cn symmetry, where n is 2 or greater, cycloalkyl groups, having a Cn symmetry , where n is 2 or greater, or groups which contain aromatics, which have a Cn symmetry, where n is 2 or greater.
6. 6. The powder coating composition according to claim 1, wherein R further comprises functional groups, selected from the group consisting of vinyl groups, urea groups, ether groups, ester groups and carbonate groups.
7. 7. The powder coating composition according to claim 1, wherein the compound (i) is selected from the group consisting of 1,6-carbamate-hexane, 1,4-d-carbamate-butane or 1, 4- dicarbamate-cyclohexane.
8. 8. The powder coating composition according to claim 1, wherein X is a primary carbamate group.
9. 9. The powder coating composition according to claim 1, wherein one or both of the component (a) and the component (b) comprise at least one interlacing agent (ii), which is reactive with the particulate compound (i) ).
10. 10. The powder coating composition according to claim 1, wherein the interlacing agent (n) is one or more aminoplast resins.
11. 11. The composition E, * powder coating, according to claim 1, further comprising one or more members selected from the group consisting of thickening agents, dispersants, surfactants, and mixtures thereof.