MXPA97004952A - Pigment inhibitor of tannin stains and hon decline - Google Patents

Abstract

A process for inhibiting stains on a film-forming finish applied to a tannin-containing wood substrate including the step of applying to the wood substrate prior to or in conjunction with the film-forming finish, a protective coating containing an effective amount of zinc cyanamide to inhibit the migration of tannins from the substrate to the end

Description

"PIGMENT INHIBITOR OF TANNIN STAINS AND FUNGAL GROWTH" BACKGROUND OF THE INVENTION Tannin stains, an undesirable process that results in aesthetic degradation and loss of decorative value of protective coatings is a problem that is often encountered, for example, with white coatings applied to wood substrates. It is usually observed as a yellowish-brown coloration or as brown spots randomly distributed over newly applied aqueous coatings and more particularly, on wood substrates coated in white and exposed to high humidity, typical condensation conditions. Water-soluble tannins or tannic acids, natural compounds of complex and non-uniform composition, are the species involved in spotting, and they are present in abundance, especially in redwood substrates. A significant example of such materials is the group known as hydrolysable tannins which are esters of hexoses (usually glucose) formed with benzoic acid or its derivatives in varying proportions of mol. Its complex composition and chemical structure are consistent with its chemical behavior and intricate physical properties, some of which are important in the tannin staining process, ie: solubility in water and in polar organic solvents, a tendency to darken in the presence of air (more specifically in alkaline media) and to form soluble or insoluble combinations, of normally dark colorations, with various metal cations. Similarly, the formation of colorful species of tanatos is observed in the presence of various insoluble or partially soluble mineral products (of pigmentation degree), in which case, apparently, the anionic species involve interference as well as with the re-linked process. . Notoriously, also the slightly acidic character of the tannins is well known. A complex phenomenon, spotting by tannin also includes several concurrent processes: penetration of water or steam into wood substrates, solubilization, diffusion within the coating and darkening of deposited tannin species exposed to air, among others. It is significant to observe in this sense that the spotting speed is controlled by means of diffusion and its extension depends significantly on the tannin concentration of the substrate. By definition, the inhibition of these spots in the sense specified above implies capabilities such as specialized coating systems, so that there is an interaction with the dissolved tannin species and interference with the related diffusion processes, thus causing immobilization. "in situ" of the stain formers which results in a total obstruction of the staining process. There are specialized pigmentation grade products known in the latest technology as "tannin blockers" or "stain inhibitors" which, as functional components of water-based or solvent-based paint formulations, provide such a protective capacity to waterborne systems. white coating applied on wooden substrates. Also the Bametaborate, of pigmentation grade is used for this purpose, or the g (OH) 2, which are known in the latest technology, and which are recommended as stain inhibitors in U.S. Pat. No. 4,218,516, issued August 19, 1980. Also, U.S. Pat. No. 3,846,148, November 1974, discloses the chemical composition and manufacturing process of such products, which consist of base pigments consisting essentially of wollastonite, talc or mica in combination with Ca or Zn phosphate or borate, or as a lubricating agent or active additive, a metal amphoteric hydrate of Al, Ti, Zr, Zn or Si. Whereas the Patent ^ 516 identified above refers to all metal hydrates specified as amphotericIt is believed that Si hydrate is typically acidic, while Ti and Zr hydrates are considered basic compounds. Consequently, the blocking activity of the tannin stain of the pigment compositions, as presented, is not necessarily correlated with the amphoteric character of the components. In a related sense, it will also be observed (as documented in the literature) that metal hydrates totally or partially dehydrated (such as alumina, silica, zirconium, etc., essentially the lubricating agents specified above) are characterized by degrees. variables of the surface acidity of Bronsted and Lewis. Based on the foregoing, it is reasonable to assume that a significant chemical reaction could not occur between such substrates, characterized by surface acidity and dissolved, slightly acidic tannin species, and, therefore, the blocking capacity is believed to be of the tannin stain of the pigments of the compound according to U.S. Pat. identified above, results mainly from its barrier function and its absorption capacity. It can be concluded that the stain inhibitors containing the metal hydrates specified as functionally active additives, according to U.S. Pat. above identified, work essentially by reducing the permeability of coating systems, and, therefore, have a relatively limited capacity to inhibit tannin stain. BRIEF DESCRIPTION OF THE INVENTION It was learned, in accordance with the present invention, that the white pigment grade zinc cyanamide products obtained according to my U.S. Pat. No. 5,176,894, issued January 5, 1993, or Patent Application Serial No. 195,783, filed on February 14, 1994, display a remarkable inhibitory activity of tannin stains as functional pigment components of protective coatings. res of the wood. It will be noted with respect to this that the chemical aspects of the interaction of solid ZnNCN with solubilized tannin species have not been documented so far in the scientific literature. Any attempt, however, to explain the outstanding stain-inhibiting capacity of the pigment-grade ZnNCN, as will be discovered hereafter, should consider, in addition to the barrier function thereof, the possibility of chemical interaction of this product with dissolved tannin species. Taking into account the relative strength of the acids involved (comparatively acidic tannin species and slightly acidic H2NCN, characterized, respectively, by K = 4.04 x 10 ~ n) this postulated chemical interaction seems possible, logically resulting in H2NCN free and more specifically, insoluble, light-colored tannates, which are ultimately responsible for the effective immobilization of dissolved tannin species "in situ" by protective coatings containing ZnNCN. In this regard, it will also be noted that the free H2NCN generated in this manner is quite reactive and supposedly capable of interfering with such intricate staining processes.

In conclusion, it is reasonable to assume that complex blocking mechanisms, including chemical interactions, as discussed above, are responsible for the effective inhibition capacity of the tannin spots of the pigmentation-grade ZnNCN, and, therefore, of the remarkable wood protective coating service formulated with such products. The conditions of service (high humidity, warm microclimate) that promote tannin stains, also promote the growth of various fungi (including mold and algae) that form typical colonies of dark coloration on the attacked surfaces causing aesthetic degradation and accelerated physical decomposition of the coating systems and finally the protected wooden substrates. Consequently, the ability to control the growth of fungi is considered an essential function of modern paints and coating formulations that will be used in wood protection, which extend the useful life and improve the overall protective performance of wood. such systems. Typically, fungicides of various chemical compositions and different toxicity are used as special paint additives to increase the fungal growth inhibiting ability of the wood protective coatings containing the traditional stain inhibition pigments. Briefly, according to the invention, there is provided a process of inhibiting stains from a film-forming finish applied to tannin-containing wood substrates, which includes the step of applying to the wood substrate previously or together with the finish film former, a protective coating containing an effective amount of zinc cyanamide to inhibit the migration of tannins from the substrate to the finish. In addition to wood substrates, the compositions and process of this invention have also been effective in blocking other stains, for example, those caused by smoke damage on structural materials such as drywall, or graffiti covering. Blocks of the stains according to the invention include at least one, and preferably more than one white stain blocking component, selected from the group consisting of zinc cyanamide, calcium cyanamide, magnesium cyanamide, strontium cyanamide, zinc carbonate, cerium carbonate, zirconium carbonate, calcium carbonate, strontium carbonate, zirconium phosphate and titanium phosphate. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1-5 are reproductions of the spectra of IR obtained by the analysis of compositions produced by the various specific Examples that are established later in this document. DETAILED DESCRIPTION OF THE INVENTION It was found that, in accordance with the present invention, the pigment-grade ZnNCN displays a dual functionality as a component of wood protective coatings: more specifically, in addition to the inhibition of tannin stains, it presents a remarkable fungal growth control activity. As a consequence, the ZnNCN, by providing both protective qualities, contributes considerably to the total service performance of such coating systems. It is preferred, in accordance with the present invention, to pre-stop the pigment grade ZnNCN by wet processes, such as those discovered in my U.S. Patent No. 5,178,894, issued January 5, 1993. and the Patent Application from the USA Serial No. 195,783, filed on February 14, 1994, now Patent No., which are typically characterized by a high test, narrow particle size distribution, large specific surface area, and relatively "open" porous texture. The chemical composition of such products, considered "neutral" zinc salts of dibasic H2NCN, is consistent with the ZnNCN formula. Depending on the manufacturing process, however, the ZnNCN is obtained in the form of crystals of "typical" or "atypical" form (which will be symbolized from now on by (T) or (AT), respectively) (as it is discovered in the Patent Application of US identified above). It was also learned, in accordance with the present invention, that the "basic" zinc salts of H2NCN, which will be referred to herein as zinc basic cyanamide, which displays an inhibitory activity on tannin stains and the growth of fungi as a pigment component of the wood coating formulations. The chemical composition of zinc basic cyanamide is consistent with a formula of ZnNCN * ZnO * H20. It is obtained in a quality of degree of pigmentation essentially by reacting the dispersed and hydrated ZnO in an aqueous medium, with H2NCN in a suitable stoichiometric ratio, according to: 2ZnO + H2NCN? ZnNCN »ZnO» H20 1. A detailed description of the manufacturing process and the relevant analytical data are presented in Example No. 4. It will be noted that the basic zinc cyanamide, similar to the neutral ZnNCN, can be obtained in crystalline form both "typical" (T) and "atypical" (AT), identifiable by a characteristic IR spectrum, as disclosed in the aforementioned U.S. Patent Application Ser. Serial No. 195,783. Predictably, Reaction 1 results in the former, while partially carbonated ZnO (as an aqueous suspension, subject to similar reaction conditions) even at a very low content of 2-3% ZnC03, is the typical precursor of the previous crystalline structure. The formula of ZnNCN »ZnO * H20, which is in agreement with the analytical data obtained, suggests the presence of free ZnO as a component of such products. The chemical behavior of zinc basic cyanamide, however, is inconsistent with: for example, it was observed that according to the present invention, an aqueous suspension of the newly formed compound, as opposed to ZnO, does not react with CO 2 gas to form basic zinc carbonate. However, zinc basic cyanamide is easily converted into neutral zinc cyanamide according to: ZnNCN »ZnO * >; H20 + H2NCN? 2ZnNCN + 2H20 2. The initial objective of the present invention in developing the pigment composite systems was to maximize the specific surface area of the active phases of ZnNCN by incorporating the finely divided support components. The development of the compound pigments based on ZnNCN characterized by the synergistic behavior with respect to the inhibitory activity of tannin stains is an objective of the present invention.

According to a related aspect of the invention, it is identified, prepared specifically or in commercially available products, characterized by the appropriate physical properties (ie, white color) and chemical properties capable of promoting synergy as supporting components of the invention. the compound pigments based on ZnNCN.

Several white pigment grade extenders of various chemical compositions were incorporated into the composite pigments according to the invention and evaluated for their synergistic contribution of the tannin stain inhibitory activity of the related compounds. In accordance with the invention, it was learned that the ZnNCN, or basic zinc cyanamide is generally compatible, as expected, with the extenders of various chemical compositions and crystalline structure; Several tested extenders, however, did not display synergistic behavior in the sense specified above or actually adversely affected the total inhibitory activity of the tannin stains of the relevant compound pigments. With regard to this, it will be noted that some mineral appressors widely used in the paints industry, i.e. talc, chlorite (aluminum hydrous magnesium silicate), MgO, as well as wollastonite (calcium silicate), belong to the latter category; apparently the Mg + and / or silicate species released by these products in the staining process are responsible for the notorious adverse interference with respect to the tannin stain inhibitory activity of the ZnNCN, the active component of the compound pigments. In addition, no significant synergy was observed with respect to the pigment compounds (according to the present invention), which contain TiO2 (Rutyl), precipitated BaSO4, mica, silica, kaolin clay (aluminum hydrated silicate), nepheline syenite (anhydrous silicate sodium, potassium, aluminum), or Zn3 (P04) 2 «2H20, SrHP04» H20, MgHPR * H20, Ca3 (P0) 2- as well as CaC03, SrC03 precipitates. However, the compounds comprising the support components listed above are generally characterized by excellent pigmentation properties, comparable to ZnNCN with respect to the inhibition of tannin stains. Several products of different chemical composition and appropriate physical properties (solubility, color) were identified according to the present invention, as exhibiting a function as a synergistic substrate component of compound pigments based on ZnNCN. In intricate physical associations with ZnNCN, or zinc basic cyanamide, such products form solid composite systems, characterized by excellent total pigmentation properties, which typically display fungal development control activity and synergism with respect to the inhibition of soil stains. tannin. It was discovered, according to the present invention, that some selected carbonates characterized by their adequate color and solubility, and more specifically: the basic zinc carbonate, the basic zirconyl carbonate and the Ce3 + or La3 + carbonate display synergy in the sense specified above . It will be noted that the carbonates, typically, are non-reactive under the subsequently specified reaction conditions. In this sense, however, zinc basic carbonate (dry product that normally corresponds to the formula of ZnC03 • 1.6 Zn (OH) 2 • 0.6 H20 and containing approximately 40-42% of ZnC03) represents a case " atypical ": as was discovered in my US Patent Application, Serial No. 195,783, if it reacts with H2HCN, forming ZnNCN and C02; consequently, it is employed, in accordance with the present invention, in a suitable stoichiometric ratio. The basic zirconyl carbonate, unlike basic zinc carbonate, does not react with H2NCN; it is characterized, however, by a limited stability to heat, and is converted by means of a drying process (carried out within moderate temperature limits of 80-100 ° C) in zirconium oxide (hydrated in degrees variables) and finally Zr02 with total loss of carbonate content. It was observed, according to the present invention, that pigment compounds containing Zirconyl basic carbonate as a carrier component, dried under the same moderate temperature conditions, retain a relatively high carbonate content, presumably due to a stabilizing effect of the related matrix. The lanthanide carbonates, corresponding to Ln2 (C03) 3 • 3-4 H20, where Ln-Ce3 +, La3 + y, preferably Ce2 (C03) 3 • 3H20 are also non-reactive, in the sense specified above. Commercially available Ce3 + carbonate (from Molycorp Inc.), a product relatively stable to heat, usually characterized by the variable carbonate content (due to the presence of Ce4 +, as well as the bicarbonate or basic carbonate species), is applied as a support component of the pigment compounds according to the present invention. It is known that cerium compounds that are efficient absorbers of U.V. (ranging from 300-400 nm) are also inhibitors of photodegradation processes of various media, specifically organic. Supposedly, the pigment compounds based on ZnNCN, containing cerium carbonate as a support component, in addition to the tannin stain inhibiting activity as well as the fungal growth control, provide an improved photostability to the coating systems. by inhibiting the degradation of related resin matrices. In addition to the carbonates as specified above, the selected phosphates, hydrated metal oxides, and Zeolites or molecular sieves were identified as supporting synergistic components of the pigment compounds according to the present invention. It was found that Ti (HP04) 2 • H20x and more specifically, Zr (HP04) 2 • H20x, which are known for their layered structure, ion exchange capacity and ability to form intercalated with organic species, together with molecular sieves of NaY or HY of ZSM-5 or Zeolites of different proportions of Si / Al, characterized (preferably, but not exclusively) by a wide-pore intersection system and a related absorption capacity, as well as the hydrated aluminum oxide, Al (OH) 3 and the hydrated oxide of Zirconium, display synergy in association with ZnNCN or basic zinc cyanamide in the above-specified aspect. To achieve an intimate association between the ZnNCN, the active component and the supporting component of such a composite pigment, the above were typically prepared by the gradual and simultaneous introduction of H2NCN and ZnO in suspension, into a well-dispersed aqueous suspension (containing the total amount) of the last compound. It will be noted, however, that, when applicable, the "in situ" and concurrent formation of both phases, ie, the active component and the support components, is the aforementioned procedure of the synthesis of a pigment compound based on ZnNCN, according to the present invention. As an example, a pre-prepared mixed aqueous suspension of ZnO and MeO (carbonate precursor) is simultaneously converted into ZnNCN and MeC03 (or basic carbonate) respectively, by means of the concurrent introduction of H2NCN and CO2 gas into the system. reaction as follows: ZnO + MeO + H2NCN + C02? MeC03 / ZnHCN + H20 3. An essentially similar principle (as will be further exemplified) can be carried out alternatively by precipitation of selected carbonates, phosphates or hydroxides, mixed with previously dispersed ZnO and by subsequent conversion of the latter into ZnNCN. The support components or their precursors, when applicable, are employed in accordance with the present invention in a finely divided form, characterized by an average particle size of l-10nm. It was a matter of consideration to investigate if the proportion of active component / support component of compound pigments could be optimized: no measurable benefit was observed with respect to functional activity, however, at content levels of 50% or greater. EXAMPLES For reasons of simplification, without intending, however, to limit the application of the present invention, all the examples presented here disclose methods of manufacturing compound pigments having the content of support component limited to practically a selected value. , typically 30-40% by weight. Various components of pigments manufactured according to the present invention are symbolized by a formula of "phase composition" which identifies the chemical composition of the support components (basic or neutral) and the crystalline structure (typical (T) or atypical (AT )) of the zinc cyanamide phase. In order to maximize the conversion of ZnO-ZnNCN, the optimum processing conditions were applied: approximately 10 mol% in excess of H2NCN (except in the case of basic zinc cyanamide), 70-85 ° C temperature and vigorous agitation of the products. However, the "in situ" preparation of the carbonate support components by the introduction of CO 2 gas into the reaction system was preferably carried out under lower temperature limits of 20-50 ° C. All synthesized compound pigments were analyzed to verify their N, Zn and carbonate contents (when applied) by Kjeldahl analytical, complexometric and volumetric gas techniques, respectively. The coating coat primer or paint formulations that are used for wood protection are typically systems of considerable complexity, based on solvents, or water. Such water-based formulations usually contain water-reducible alkyd or acrylic resins as film-forming components, filler pigments and water as their main components. They also contain several functional components, such as: pigment stain inhibitor, coalescing solvent, dispersants, defoamers, thickeners, neutralizers and biocides in adequate amounts. All the functional characteristics, including to some extent, the blocking capacity of tannin stains of wood protective coatings depend on the density that is respectively intermolecular binding of the chemical composition of the main components (such as fillers and fillers). polymer matrices), respectively. It will be noted, however, that it is the pigment stain inhibiting component, which represents only 5-6% of the solid phase, which determines the blocking performance of the tannin stains of the resulting coatings. A primer formulation prepared in accordance with Example 11, with varieties of compound pigments obtained in accordance with the present invention, was employed as a test system to calculate and quantify the tannin stain inhibitory activity of such ZnNCN-based products. . To this end, the related variations of the first formulation were applied by means of a 3 mil bar. on topcoat redwood panels, which had been aged for several days and subsequently subjected to moisture condensation conditions for 24 hours. By measuring the magnitude of the resulting discolorations of the test panels by means of a computer-aided reflectance spectrophotometer, the results were obtained and expressed in an FMCII color measurement system versus related and unexposed control displays, in where the relevant formulations were applied on white substrates that did not stain. The protective performance of the various apostants and the inhibitory activities of the tannin stains of the relevant composite varieties were evaluated and quantified in this way. The fungal growth inhibition activity of the pigment grade ZnNCN and the selected pigments based on selected ZnNCN was evaluated on wood and gypsum test panels as described above following the specialized test procedure recommended by ASTMD-3273. EXAMPLE 1 Compound pigments were prepared, characterized by excellent tannin stain inhibitory activity and control of fungal growth, symbolized by the phase composition formulas: 1.1: Ce2 (C03) 3 • 3H20 / ZnNCN (T) 1.2: Al (OH) 3 / ZnNCN (T) 1.3: Valfor molecular sieve CBV-400 / ZnNCN (T) The support components according to 1.1, 1.2 and 1.3 are available from Molycorp, Inc., Nyco Minerals, Inc. and the PQ Corporation, respectively. The compounds were synthesized according to the following procedure: Aqueous dispersed and hydrated aqueous suspensions were prepared concurrently from varieties of the selected components of the substrate and, separately, from highly reactive ZnO, by introducing 300.0 g. of any such product by means of small increments, as specified, and 543.0 g. (6.67 moles) of ZnO grade AZO 66 (from the American Smelting and Refining Co.), respectively, in two separate volumes of 1000 ml. of hot water each, by means of a very vigorous mixing.

The dispersion and hydration process of all these suspensions (various substrate and ZNO components) was terminated by maintaining the same conditions for one hour at 75-85 ° C. Subsequently, compound pigment varieties were produced by simultaneously introducing in about 60 minutes the previously prepared ZnO suspension (as described above) and 313.0 g. (7.45 mole) of H2NCN (used as a 25% aqueous solution, available from S.K. - Germany) within the previously prepared suspensions, and intly mixed with any substrate component. The conversion of ZnO to ZnNCN was terminated by maintaining the same reaction conditions (vigorous mixing, 75-85 ° C) for approximately 1 hour after the introduction of the reagents was completed. Subsequently, the solid phases of the resultant product suspensions were separated by vacuum filtration, and without washing, the agglutinates in the form of pellets obtained by press action were dried at 105-110 ° C for 12 hours and finely pulverized to a measure of 100% + 270 mesh. The waters collected from the treatment were totally recyclable. Since the products selected as support components are essentially non-reactive under the reaction conditions found above, the yields obtained were all approximately 1002.0-1060.0 g.

Typical pertinent analytical data for the tannin stain inhibitory compound pigments of formulas 1.1, 1.2 and 1.3 show that they all contained about 70% by weight of ZnNCN as active component and about 30% by weight of the selected component of synergistic support, as shown in Table 1. TABLE 1 No. Phase Composition Calculated / Determined Values of Synthetic Pigments Quality parameters% N% Zn% Support Specific Gravity 1 . 1 Ce2 (C03) 3 • 3H20 / 16.05 51.8 9.5 (as 3.0 ZnNCN (T) (C03) 1 .2 Al (OH) 3 / ZnNCN (T) 15.2 45.1 29.4 2.6 1 .3 CBV-400 / ZnNCN (T) 15.5 45.5 30.0 2.3 The yields obtained and the corresponding chemical compositions (based on the presented analytical data) are shown below: Chemical Composition of Synthesized Pigments Yield, g. 1.1: 0.09 Ce2 (C03) «3H20 / ZnNCN • 0.38ZnO 1058.0 1.2: 0.73 Al (OH) 3 / ZnNCN • 0.27ZnO • 0.04H2O 1020.0 1.3: 30% CBV-400 / ZnNCN • 0.26ZnO 1002.0 The IR Spectrum characteristic of 1.3, CBV-400 / ZnNCN (T) is presented in Fig. 1. EXAMPLE 2 The compound pigment corresponding to zinc / ZnNCN basic carbonate (AT) was synthesized as follows: Basic zinc carbonate (corresponding at ZnC03 • 1.6 Zn (OH) 2 • 0.6 H20 available from Aldrich Chemical Co.) in suspension was prepared by dispersing 1050.0 g. of finely ground material in 2000 mi. of hot water and was stirred vigo-rosamente and by maintaining the same conditions at 75-85 ° C for 1 hour. The composite pigment, according to the present invention, was synthesized by introducing, for about 1 hour, 306.0 g. (7.28 moles) of H2NCN, used as a 25% aqueous solution, within the suspension of basic zinc agitated vigorously stirred, which had been previously prepared, while maintaining the temperature of the reaction mixture at 75-85 °. C. The conversion process was completed by maintaining the same processing conditions for an additional 1 hour. The resulting pigmentation grade compound slurry was also processed in an identical manner as was found in the relevant part of Example 1. The typical analytical data for the compound pigment containing ZnNCN (AT) as active component and basic carbonate. Zinc as a support component (in this case at approximately 60% to 40% weight ratio, respectively) are presented below.

TABLE 2 Parameter Analyzed / Tested Values < determined Specific gravity 2. 94% N as N 16. 22% Zn as Zn 60. 04% ZnC03 17. 0 Performance 997.0 g.

Based on the analytical data presented above, the chemical composition of the compound pigment corresponds to ZnNCN • 0.23ZnCO3 • 0.35Zn (OH) 2 • 0.17 H20. The relevant IR spectrum is presented in Fig. 2. EXAMPLE 3 A pigment composed of chemical composition and physical structure similar to that found in Example 1, corresponding to the formula of the phase composition CaCO3 / ZnNCN (AT), is produced by carrying out the synthesis of the active compound ZnNCN and the synergistic support component, simultaneously "in situ" of the reaction medium using the following procedure: A well-disperse, hydrated reactive mixture suspension was prepared by introducing into small increments the amount of 543.0 g. of ZnO (preferably of AZO-66 grade) and the appropriate amount, 168.0 g. of CaO, the carbonate precursor oxide, in 2000.0 ml of hot water vigorously mixed at 75-85 ° C. The reactive mixed suspension of ZnO and CaO, the carbonate precursor oxide, was subsequently converted into a composite pigment by introducing continuously for about 1 hour into the vigorously mixed reaction medium, C02 gas at a manageable rate, and at about 5 hours. minutes of relative delay (but essentially simultaneously), 295.0 g. (7.0 moles) of HnNCN as a 25% aqueous solution of the same quality as specified in Example 1. Subsequently, the conversion process was completed by maintaining the temperature of the suspension obtained at 30-40 ° C and by stirring continues for about 2 hours. More importantly, however, the pH of the reaction medium was constantly measured and corrected periodically at pH = 7-7.5 by means of additional C02 introductions, carried out intermittently, as necessary. Typically, stable pH values of the reaction media were observed after 7-8. The obtained pigment composite suspension was processed identically as discussed in the applicable section of Example 1. The relevant analytical data is shown below. TABLE 3 Parameter Analyzed / Tested Values determined Specific gravity 2.64% N as N 16.7% Zn as Zn 42.16% CaC03 30.0 Performance 997.0 g.

Based on the analytical data presented above, the chemical composition of the compound pigment corresponds to 0.5 CaC03 / ZnNCN (A-T) • 0.08 ZnO • 0.3 H20. EXAMPLE 4 Basic pigment-grade zinc cyanamide, containing a chemical composition corresponding to ZnNCN • ZnO • H20, characterized by an increased inhibition activity of tannin stains and fungal growth was produced according to the following procedure: A reactive suspension, well hydrated, containing 407.0 g. (5.0 moles) of ZnO in 1000.0 ml. of water was prepared in a manner similar to that found in the corresponding part of Example 1, cooled to 30-40 ° C and subsequently converted to basic zinc cyanamide (suspension) by introducing 105.0 g for about 1 hour. (2.5 moles) of H2NCN, added as a 25% solution, while maintaining the temperature of the reaction medium at 20-50 ° C. The conversion process can be completed in about 1 hour at 20-85 ° C, under intense agitation. After separation, the solid phase was washed with limited amounts of H20, dried overnight at the critical temperature of 75-80 ° C and processed as found in the applicable part of Example 1. Relevant analytical data and the IR spectrum are presented below and respectively in Fig. 3. TABLE 4 Quality Parameters Analyzed / Tested Values determined Specific gravity 3.38% N as N 13.6% Zn as Zn 62.6% ZnC033 as ZnC03 1%% H2C 10.5% Performance 490.0 g .

Based on the analytical data presented above, the chemical composition of the product corresponds to ZnNCN • 0.97ZnO • 1.2 2H20. EXAMPLE 5 The composite pigment corresponding to basic zinc carbonate / basic zinc cyanamide (A-T) was prepared according to the procedure as follows: A reactive, well dispersed and hydrated suspension of ZnO was prepared by introducing 298.0 g. (3.66 moles, AZO 66 grade) of such product in 1500 ml. of hot water at 75-85 ° C, maintaining the same conditions for one hour, and then cooling it to about 40 ° C. The prepared suspension of ZnO was divided by weight into two parts, A and B, which contained practically 178.0 g. and 120.0 g. of ZnO, respectively. Subsequently, part B that contained 120.0 g. ZnO was converted into a basic zinc carbonate suspension by continuously introducing into it within about one hour, and under vigorous agitation, C02 gas at a manageable speed. A mixed suspension of ZnO and basic zinc carbonate was obtained by unifying A and B which was first heated to 70-80 ° C, and then converted into a composite pigment suspension. To that end, 48.0 g were introduced under vigorous mixing and at 70-80 ° C. (1.14 moles) of H2NCN (as a 25% aqueous solution) to the mixed suspension for about 15-20 minutes. The conversion process was completed by maintaining the same conditions for an additional hour, and subsequently, the suspension obtained from compound pigment was processed identically as presented in the applicable part of Example 1.

The relevant analytical data are presented under: TABLE 5 Parameter Analyzed / Tested Determined Values Specific Gravity 2. 92% N 7. 91% Zn 61 15% ZnC03 23. 7 Yield 379.1 g.

Based on the analytical data presented above, the chemical composition of the compound pigment corresponds to 0.67 ZnC03"0.64 ZnO • 0.2 H20 / ZnNCN • ZnO • H20. The related IR spectrum is presented in Fig. 4. EXAMPLE 6 A composite pigment corresponding to the zirconyl carbonate / ZnNCN (T) basic phase formula was obtained by the following procedure: A well dispersed, hydrated suspension was prepared and reactive ZnO, which contained 220.0 g. (2.7 moles) of such product in 1000 ml. of H20, in the manner already presented and which is typical of the invention. Concurrently, a solution of zirconyl sulfate was prepared by dissolving 245.0 g. of such product (which is available from Magnesium Elektron, Inc. as H2ZrO (S04) 2 • 3H20, ensa-yo: 32% Zr02) in about 1000 ml. of H20 and they were converted into a basic zirconyl carbonate suspension by the addition of Na2C03 (about 195.0 -200.0 g required) until a constant value of pH = 8.5-9.0 was achieved. The composite pigment was produced by adding the basic zirconyl carbonate suspension to the ZnO suspension, mixing the mixed suspension for about 30 minutes at 40-50 ° C and by the subsequent introduction into it, for about 30 minutes, of 120.0 g. (2.85 moles) of H2NCN (as a 25% solution). The conversion process was terminated by maintaining the same conditions for an additional hour, after which the solid phase was separated by filtration, washed in salt-free conditions and further processed in a manner similar to that described in the section appropriate from Example 1. The appropriate analytical data are presented below: TABLE 6 Parameter Analyzed / Tested Severed values Specific gravity 2.84% N 16.58% Zn 43.83 carbonate as% C03 5.92 carbonate as% ZrO (OH) (C03) 0.5 30.4 Yield 391. 1 g.

Based on the analytical data found above, the chemical composition of the synthesized compound pigment corresponds to: 0.33ZrO (OH) (C03) 0.5 / ZnNCN • 0.13 ZnO • 0.07H2O. EXAMPLE 7 Compound pigments, containing zinc basic cyanamide as an active component, correspond to the phase composition formulas: 7.1 HY Zeolite / basic zinc cyanamide (T) 7.2 Diatomaceous silica / zinc basic cyanamide (T), and were produced according to essentially the procedure discovered for Example 1, except that the molar proportions for the raw material used were as follows: TABLE 7 Raw Materials Quantities in grams per products synthesized 7.1 7.2 ZnO (grade AzO 66) 178.0 178.0 (2.18 moles) H2NCN (SKW, Germany) 48.0 48.0 (1.14 moles) Zeolite HY (CBV-760 165.0 from Corp. PQ) Diatom Silica 165.0 (Ultra-grade grade from Eagle Picher Minerals, Inc.) Relevant analytical data are presented below: TABLE 8No. Composition of Phase Calculated Values / Determined of Synthetic Pigments Quality parameters ticked% N% Zn% Support Specific Gravity 7. 1 Zeolite HY / ZnNCN 7.1 39.02 43.7 2.45 Basic (T) 7.2 Silica / ZnNCN 7.83 38.18 44.0 2.58 Basic (T) The recovered yields and the corresponding chemical compositions (based on the analytical data presented above) are provided below: Chemical Composition of Synthesized Pigments Yield, g. 7.1 43.4% Zeolite HY / ZnNCN «1.35 ZnO 380.0 • 1.6 H20 7.2 44% Silica / ZnNCN • 1.08 ZnO 375.0 • 1.31 H20 EXAMPLE 8 The compound pigment containing zinc basic cyanamide as active compound, which corresponds to the zirconyl hydrated oxide / basic ZnNCN phase composition was obtained in essentially the same manner in all details as was found in Example 7, except that in this case the support component was prepared by precipitating dissolved zirconyl species such as Zr (OH) 2 • H20x. For that purpose, 415.0 g were dissolved. of zirconyl sulfate (see also Example 6) in 1,500 ml. of H20 and converted into a suspension of ZrO (OH) 2 • H2Ox by the addition of 210.0 g. (5.25 moles) of NaOH until brought to a stable pH = 8.5-9.0, subsequently incorporated into the composite pigment and processed as described in Example 7 and, respectively, in Example 1. The relevant analytical data are presented below: TABLE 9 Parameter Analyzed / Tested Val. ores < determined ies Specific Gravity 3. 28% N 7. 8% Zn 36. 0% Basic Zinc Cyanamide 56. 39% Substrate 43. . 6 Performance 410.0 g.

Based on the above-discovered data, the chemical composition of the synthesized pigment corresponds to: 1.07 Zr02 • 2.5H20 / ZnNCN • 0.97 (ZnO • H20).

EXAMPLE 9 The compound pigments consist of zinc basic cyanamide as the active component, zirconyl phosphate or titanyl as the support component and correspond to the phase composition formulas of: 9.1 Zr (HP04) 2 / ZnNCN Basic (T) 9.2 Ti (HP04) 2 / Basic ZnNCN (T) that were produced essentially in a similar manner to that presented in Example 7, except that in these cases the support components were prepared as follows: A sulphate solution of zirconyl (9.1) or titanyl sulfate (9.2) when solubilizing 223.0 g. of the first product (available from Magnesium Electron, Inc., with a Zr02 assay at 32%) or 650.0 g. of the second product (available from Kemira, Inc., with an assay of Ti02 at 9.8%), respectively, in approximately 2,000 ml. of H20. Subsequently, aqueous suspensions of Zr (HP04) 2 • H2Ox or Ti (HP04) 2 • H20x were produced by introducing, under vigorous stirring, 170.0 g. (1.47 moles) of H3P04 (as a 40% solution) within each solution and by the subsequent addition of NaOH until reaching a stable pH of 8.0-9.0. The incorporation of the support components into the corresponding compound pigments, 9.1 and 9.2, respectively, was subsequently carried out on all of the details described in Example 7, including washing the products under salt-free conditions as described. described for Example 1. The related analytical data are presented below: TABLE 10 No. Phase Composition Calculated / Determined Values of Synthetic Pigments Quality parameters% N% Zn% Support Specific Gravity 9. 1 Zr (HP04) 2 / ZnNCN 7.94 36.14 43.37 2.80 Basic (T) 9.2 (Ti) (HP04) 2 / ZnNCN 7.54 34.65 47.0 2.73 Basic (T) The yield, the IR spectrum corresponding to 9.1 and the appropriate chemical compositions (based on the analytical data presented above) are shown below, and respectively, in Fig. 5. Chemical Composition of Synthesized Pigments Yield, g. 9.1 2.04Zr (HPO4) 2 • 0.38H20 / ZnNCN 395.0 • 0.95 (ZnO • H20) 9.2 2.96Ti (HP04) 2 • 0.2H2O / ZnNCN 415.0 • 0.96 (ZnO • H20) EXAMPLE 10 The compound pigment based on ZnNCN and three mixed support components according to the carbonate phase composition formula of Ce, basic carbonate of (Zn + Zr) / ZnNCN "(AT), was prepared according to the following procedure: A suspension previously prepared (see applicable and pertinent section of Example 1), well dispersed, hydrated and reactive of ZnO containing 300.0 g (3.68 moles) of this product in 1,000 ml of H20 was converted into a mixed suspension of hydroxides (cerium carbonate mixing precursors, basic zirconyl carbonate, zinc basic carbonate) by first cooling to 40-50. ° C, then introduced into 125.0 g of zirconyl sulfate (as specified in Example 9), 140.0 g of Ce (N03) 3 (from Molycorp Inc., characterized by a 34.5% Ce02 test) and then After approximately 10 minutes, 83.0 g of NaOH (2.07 mol) were applied under vigorous stirring, and the carbonization of the mixed suspension of hydroxides was subsequently carried out by continuously introducing, into the vigorously stirred reaction medium, 25- 35 ° C, gas C02 au at a manageable speed for about an hour. The composite pigment, according to the phase composition formula discovered above, was obtained by introducing afterwards, for about 30 minutes, 141.0 g. of H2NCN (3.36 moles, as a 25% aqueous solution) into the reaction medium and finishing the conversion process by stirring at 25-40 ° C, for about two hours. The obtained composite pigment was subsequently processed as described in the applicable section of Example 6, inclusive with a wash under salt-free conditions. The related analytical data are presented below: TABLE 11 Parameter Analyzed / Tested Determined values Specific gravity 2, .82% N 15, .91% Zn 47. .66% Total of C03 (as C03) 5. .6% ZnNCN 59. .9% Support 40, .1 Performance 510.0 g.

EXAMPLE 11 A typical water-based, water-based formulation with stain blocking feature is presented below. (designed for wood protection) used as a test system (applied on redwood panels) according to the present invention: Table 12 Components Commercial Name of the Parts by Component Weight Pigment Compound Produced according to 33.0 Stain Blocker present invention * Ti02 300.0 Tamol Dispersant 681 (1) 20.0 Triton Stabilizer CF-10 (2) 2.0 Thickener QR-708 (1) 6.0 Foamaster VL Anti-Foaming Agent (3) 2.0 28% Ammonia 1.0 Coalescent Solvents-Ethylene Glycol 20.0 te Texanol (4) 5.0 Rhoplex Resin MV-23 (1) 520.0 Water 200.0 + except commercial products The component suppliers are: (1) Rohm & Haas, (2) Union Carbide, (3) Henkel Co. , and (4) Eastman Chemical Co .. After the test procedure described above, the blocking activity of tannin stains of various compound pigments (synthesized in accordance with the present invention and employed as functional components of the discovered test formulation in Table 12 was finished on redwood panels, the results are presented in Table 13. The measured E values, which qualify the magnitude of the observed changes in color are also inversely proportional with respect to the activity tested Pigment stain blockade The above-identified? E values (observe the control and commercial products for comparison) indicate a remarkable activity of tannin staining of the pigmentation grade of ZnNCN and basic ZnNCN, as well as the synergistic behavior, in the same sense, of the pigment-related compounds synthesized according to the present invention Table 13 Pigments Blocking Stains Related Activity Tested for Blocking Tannin Stains, Measures as? E According to the Example Composition # Control Phase, without stain blocking agent * N.A. 18.0 1.1 Ce2 (C03) 3 • 3H20 / 7.0 ZnNCN (T) ZnNCN (T) 9.5 4. ZnNCN • ZnO • H20 (T) 9.0 5. Basic Carbonate of 7. 5 Zinc / ZnNCN Basic (A-T) 9.1 Zr (HP04) 2 / ZnNCN Basic 6. 5 (T) 1.2 Al (OH) 3 / ZnNCN (T) 8. 5 1.3 Zeolite / ZnNCNfT) 8. 0 Commercial product Based on Borate 10. 5 Commercial product Based on Phosphate / 12. 0 Silicate * Compensated by the same amounts of Ti02. ** Produced in accordance with US Pat. UU No 5, 176, 894, EXAMPLE 12 The fungal growth retarding activity of pigment grade ZnNCN was evaluated following the recommendations of the specialized test procedure by ASTM-3273. For this purpose, paint formulation variations (as presented in Table 12) containing pigment-grade ZnNCN (produced in accordance with US Patent No. 5,176,894), stain-blocking pigment based on borate (commercially available, also recommended as a fungicide in paint formulations) and control formulation without stain blocker, respectively, on pine and gypsum substrates and subjected to test conditions. The extent of discoloration caused by the growth of fungi on the test coating surfaces, an indicator of the inhibitory activity of the tested products, was evaluated visually and graded on a scale ranging from 10 (no disfigurement) to 1 (no there is inhibition of fungal growth). The relevant results presented below indicate the manifestation of a remarkable fungal growth control activity for the pigmentation grade ZnNCN. Table 14 Inhibitor Degree of Inhibition of Fungus Growth on Substrates of: Pine Plaster None (formulation of 2 control) Ba modified metaborate 3 ZnNCN 7 The foregoing is considered as illustrative only of the principles of the invention, since numerous modifications and changes will be apparent to those with cutting edge technology. The invention should not be considered limited to the exact compositions shown and described and, in accordance with the foregoing, all suitable modifications and equivalents can be considered as falling within the true limit of the invention.

Claims (13)

1. NOVELTY OF THE INVENTION Having described the invention, it is considered as a novelty and, therefore, the content of the following clauses is claimed as property. CLAUSES 1. A process for inhibiting the staining of a film-forming finish applied to a tannin-containing wood substrate, comprising the step of applying to the wood substrate, prior to or in conjunction with the film-forming finish, a coating protector containing an effective amount of zinc cyanamide to inhibit the migration of tannins from said substrate to said finish.
2. 2. A process according to Clause 1, wherein said composition also contains basic zinc carbonate.
3. 3. A process according to Clause 1, wherein said zinc cyanamide is applied in the form of an aqueous suspension.
4. 4. A process in accordance with the Clause. 1, wherein said protective coating also contains a metal oxide or hydroxide.
5. 5. A process for inhibiting the staining of a film-forming finish applied to a tannin-containing wood substrate consisting of the step of applying to the wood substrate, prior to or in conjunction with the film-forming finish, a protective coating that contains an effective amount of ZnNCN • ZnO • H20 to inhibit the migration of tannins from said substrate to said finish and to inhibit the growth of fungi.
6. 6. A process according to Clause 5, wherein said protective coating also contains a synergistic support component.
7. 7. A stain blocking, fungal growth inhibiting composition for stain protection of paint coatings on a substrate consisting of at least one, and preferably more than one white stain blocking component selected. of the group consisting of zinc cyanamide, calcium cyanamide, magnesium cyanamide, strontium cyanamide, zinc carbonate, cerium carbonate, zirconium carbonate, calcium carbonate, strontium carbonate, zirconium phosphate and titanium phosphate.
8. 8. A composition according to Clause 7, wherein the zinc cyanamide consists of about 3 to 50 percent by weight of the composition.
9. 9. A composition according to Clause 8, which also comprises a support component selected from the group consisting of a basic carbonate of zinc, zirconium, cerium, lanthanum, calcium or strontium.
10. 10. A composition according to Clause 8, comprising as support component a zeolite or molecular sieve characterized by large pore intersection structures and having a high absorbent capacity.
11. 11. A composition according to Clause 8, which comprises as a support component a partially or totally dehydrated oxide of Zr, Al, Si or Zn.
12. 12. A composition according to Clause 8, which comprises as a support component a hydrophophate selected from the group consisting of Zr (HP04) 2xH20, Ti (HP04) 2xH20, and Sr (HP04) 2xH20.
13. 13. A composition according to Clause 12, wherein said phosphate support component is formed in situ from a suspension of ZnO to which H2NCN is subsequently added, by the concurrent introduction of H3P04 or Na3P04 and a watery paste or solution of a hydroxide, carbonate or basic carbonate of Zr, Ti, or Mr.