RU2346967C1 - Method for production of alkyd-urethane enamel - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to paint-and-varnish industry, in particular to method for production of alkyd-urethane enamels of various colours, and may be used to produce protective-decorating enamel coatings applied onto various substrates. Method for production of alkyd-urethane enamel is described. This method implies preparation of individual precursor components, their dosing, preparation of intermediate enamel product by combining alkyd pentaphthalic lacquer with dispersing medium, organic solvent and rheological agent, the mixture being stirred at 300-500 rpm, followed by introduction of free-flowing pigments into the mixture, together with filler, when required. Pigments and filler are pre-dispersed under stirring at a speed up to 1000 rpm until homogenous suspension is obtained. Then intermediate product is further dispersed until required degree of grinding is obtained, alkyd-urethane lacquer is added under stirring and, when required, anti-crater additive and paint dryer are added. Then, pigment tinting paste is added, the mixture is stirred to obtain homogenous suspension, and antiskinning agent is added.

EFFECT: production of alkyd-urethane enamels of various colours, with high physical and chemical properties.

10 cl, 5 tbl

Description

The invention relates to the paint and varnish industry, and in particular to a method for producing alkyd-urethane enamels of various colors, and can be used to obtain enamel coatings used as protective and decorative coatings on various surfaces, including metal, concrete, reinforced concrete, wood, plastered surfaces , and can be used in various industries, as well as for coloring agricultural and road equipment, technological equipment and other metal ble and wood surfaces requiring good decorative properties and long life in the atmospheric conditions and indoors.

It is well known that enamels belong to pigmented paint compositions, contain a large amount of film former per unit volume of pigment and fillers (i.e. these are relatively low-filled systems) and form shiny and decorative coatings; they are intended to produce topcoats.

It is known that the production of paints and varnishes, including enamels, varies depending on the type of film-forming system. Liquid pigmented paints and varnishes are aggregatively stable suspensions of pigments either in a solution or dispersion of a film former or in an oligomeric film former without volatile components.

The technological process for producing pigmented paints and varnishes, including enamels, as a rule, consists of the following basic operations:

1) mixing varnish with pigments, fillers, plasticizers, hardeners and other additives (preparation of the batch);

2) dispersion of the obtained paste (milling);

3) dilution of grated paste with an additional amount of varnish and adjusting to the required conditions in terms of viscosity, solids, color (tinting) and other properties - obtaining an enamel product;

4) cleaning of weeds, etc. (on filters, centrifuges, etc.);

5) packaging.

Moreover, there are various methods for the manufacture of enamels as pigmented paints and varnishes: the method of single-pigment (single-collier) pastes and the method of multi-pigment (multicolor) pastes.

With the method of single-pigment pastes, pastes of various pigments are separately prepared, after which they are mixed in the desired ratio. The method of multi-pigment pastes consists in mixing pigments at the stage of kneading and their joint dispersion (I.S.Okhrimenko, V.V. Verkholantsev “Chemistry and technology of film-forming substances.” L .: Chemistry, 1978, p.341, 343-346) .

It is obvious that the final properties of enamels and enamel coatings depend on both their composition and the preparation method.

From SU 1495348, 07.23.1989, a method is known for preparing alkyd pentaphthalic enamel by preliminary dispersing a mixture of pentaphthalic varnish (for example, varnish PF-060), pigments (titanium dioxide, yellow lead crown, lemon yellow crown), fillers (microbarite, by-product of production perborate sodium), subsequent grinding of the mixture to a degree of milling according to the "wedge" of not more than 25 microns, adding desiccant and diluting the enamel to a working viscosity of 28-30 s in B3-4 solvent. The resulting enamel does not have the necessary weather resistance and wear resistance.

From RU 2298573, 05/10/2007, a method is known for producing a uralkyd paint composition comprising a modified uralkyd resin, desiccant, antioxidant (methyl ethyl ketoxime), an organic solvent (xylene, white spirit or a mixture thereof) by mixing an oligomeric base (uralky resin in an organic solvent ) with desiccant and antioxidant at room temperature. However, this composition does not apply to enamels and is intended for transparent protective coatings for metal, wood and concrete.

From RU 2192441, 11/10/2002, there is a known method for producing a pigmented coating composition containing a first polyurethane dispersion (A) with an acid number of more than 20, a second polyurethane dispersion (B) with an acid number of less than 20, additives that control the acid number, a neutralizer ( tertiary amine) and the corresponding color pigment and / or decorative pigment; component (B) may further comprise a polyester resin. As a decorative pigment, the composition contains, for example, flake pigments in the form of metal powder; as a colored pigment - titanium dioxide, pigments based on iron oxides, soot, azo pigments and others.

In the case where the composition contains a colored pigment, the latter — before the mixing process of both components A and B — is introduced into composition A. It is particularly preferable to grind the colored pigment with component A to obtain the desired grain size of this pigment. In the case when the coating composition contains a decorative pigment, the latter - also before the process of mixing both components A and B - is introduced into B. For this purpose, the decorative pigment can be ground in composition B, for example, as follows: first, this the decorative pigment, which is a commercially available product, mostly supplied in powder or paste form, is preferably mixed with water-diluted organic solvent and appropriate additives and processed of a paste. It is necessary to prevent the possibility of mechanical damage to decorative pigments in the mixing process.

This known composition is water-borne and is intended to produce coatings by electrodeposition, primarily for painting cars.

From RU 2001931, 10/30/1993, there is known a method for producing enamel, which consists in preparing a pigment paste containing a polymeric binder (a mixture of pentaphthalic resin and melamine-formaldehyde resin), white pigment, filler, aluminum powder, surface-active substance (surfactant) and an organic solvent, as well as a tinting paste containing a coloring pigment, a polymeric binder, a surfactant and an organic solvent, are then separately dispersed by vibrocavitation grinding with an oscillation frequency of 100-190 Hz, amplitude (2.5-4.4) × 10 ^-4 m 3 -5 mi n Pastes are served in the mixer to obtain finished enamel.

The method is intended to obtain enamels with a metallic effect, is intended for coloring car bodies, in addition, it is quite complicated.

The technical task of the claimed invention is to obtain enamels with a rich wide color gamut and increased strength and protective properties, for example, such as acid-base, oil resistance, weather resistance, resistance to UV radiation in a wide temperature range under various climatic conditions with high adhesion and elasticity of the film coverings.

The problem is solved due to the fact that the method for producing alkyd-urethane enamel according to the invention includes the possible preliminary preparation of the individual starting components, their dosage, preparation of the semi-finished enamel by combining alkyd pentaphthalic varnish with a dispersant, an organic solvent and a rheological additive with stirring at a speed of 300-500 r / min, subsequent introduction into the resulting mixture of loose pigment components and, if necessary, a filler with their preliminary dispersion with stirring at a higher speed up to 1000 rpm until a homogeneous suspension is obtained, further dispersing the semifinished product until the desired degree of milling is achieved, then introducing into it with stirring uralkid varnish and, if necessary, anti-crater additive and desiccant, and then introducing pigment tinting paste, mixing until complete homogeneity of the suspension and the introduction of anti-film additives.

At the same time, they can carry out preliminary preparation of components such as a rheological additive, in the case of using benton (bentonite clays, kaolins), and an anti-crater additive - polymethylsiloxane liquid in the form of a 0.9-1.1% solution in xylene or toluene .

A benton-based rheological additive can be prepared previously in the form of a paste consisting of benton and white spirit, and then this paste is activated by introducing acetone or ethyl alcohol or isopropyl alcohol into it.

If it is necessary to additionally introduce tinting paste while adjusting the required enamel color to normal, tinting paste can be prepared with a predefined color scheme to obtain the following enamel: window gray, basalt gray, bright green, ruby red, signal red, deep black.

To obtain the enamel of the desired color, for example, pigments such as scarlet 2C, red C, blue phthalocyanine 15: 1, 15: 3 (Holliday), green phthalocyanine 7, Bayferrox 110, Versal Vellow 2 GXD, Versal Scarlet R, Versal Orange HLD, Hansa Brilliant gelb 2GX70, carbon black, Bayferrox 920, Bayferrox 130 BM, violet 23, carbon black SB-4, pigment Hostaperm-Green GNX, phthalocyanine pigments Hostaperm-Blue A4R 15: 1 and B-2G-L 15 : 3 (Clariant).

The preliminary dispersion can be carried out, in particular, until a viscosity of 100-120 s is achieved according to B3-4, preferably within 30-40 minutes.

Semifinished product can be dispersed at a temperature not exceeding 60 ° C, preferably up to a milling degree of not more than 25 microns (for glossy and semi-gloss enamels), or not more than 30 microns (for semi-gloss and matte enamels), or not more than 50 microns (for silver enamels )

The following is a specific example of obtaining alkyd-urethane enamel by the method according to the invention, which illustrates the invention, but does not limit it.

Example. The method consists of the following stages, in particular, and includes:

- reception and dosage of raw materials;

- preparation of benton paste;

- manufacture of semi-finished products;

- dispersion;

- statement on "type";

- packing.

Preliminary carry out the preparation of the following components (preliminary preparation).

- Carry out the preparation of bentonite in the form of a paste.

The benton rheological additive is loaded into the semi-finished product as a paste at the stage of loading the liquid components. To load 1 ton of the semi-finished product into a separate container, 12 kg of white spirit and 5 kg of benton are loaded, carefully mixed until smooth by hand. After that, in order to activate benton, add 3 kg of acetone (it is possible to replace acetone with ethyl alcohol) and mix until a homogeneous plastic mass is obtained.

- Carry out the preparation of anti-crater additives.

Anti-crater additive - polymethylsiloxane liquid in the form of a 0.9-1.1% solution (1% in this example) in xylene.

- Then carry out the preparation of the semi-finished product.

The manufacture of semi-finished products is carried out in a bowl under the dissolver by the method of skinny pastes. The components are loaded according to the flow chart. The amount of PF-060 light-colored pentaphthalic alkyd varnish specified by the recipe from the collection is pumped into the weight meter by a pump, from where it is pumped through a flexible hose into a bowl.

The bowl is installed under the dissolver, the mixer is turned on, and at a shaft rotation speed of 300-500 rpm, the previously weighed dispersant and rheological additive benton in the form of a paste are manually loaded. As a substitute for benton, benton SD-1 or Viscogel ED are used, which are loaded in powder form when loading loose components.

After loading the liquid raw materials, stirring is carried out for 20 minutes and, with the working dissolver stirrer, pre-weighed bulk components are loaded in portions. At the end of loading, the shaft speed is gradually increased to 1000 rpm and preliminary dispersion is carried out for 30-40 minutes until a homogeneous suspension is obtained.

In the process of preliminary dispersion control the viscosity of the semi-finished enamel, which should preferably be 100-120 C. At a viscosity of more than 120 s, a solvent is added to the suspension. After each addition of solvent, the paint material is mixed for 15-20 minutes and the viscosity is checked. After adjusting the viscosity to the norm, the semi-finished product is transferred to dispersion.

- Dispersion of semi-finished products.

Dispersion is carried out on two sequentially installed vertical bead mills or horizontal bead mills.

Semi-finished cake bowl is fed to bead mills, mounted on a stand, and one or two bead mills are connected to the feed pump with flexible hoses. To prevent strong heating of the material during dispersion, the bead mill container is equipped with a water jacket. The temperature of the dispersible material at the outlet of the container should not exceed 60 ° C in order to avoid polymerization of the paint material. After connection, cooling water is supplied to the container jacket and the bead mill engine is started. The semi-finished product enters the grinding chamber of the bead mill container, filled with grinding media. The degree of grinding depends on the residence time of the dispersible material in the grinding zone. After the dispersion starts, the feed rate of the semi-finished product to the mill is adjusted so that the degree of grinding at the outlet of the mill meets the requirements of the technical specifications for enamel. The degree of grinding in glossy and semi-gloss enamels should be no more than 25 microns, semi-matte and matte - no more than 30 microns, silver - no more than 50 microns. Intermediate control of the degree of milling is carried out by a replaceable laboratory assistant. Upon reaching the desired degree of grinding, the suspension is collected in a bowl or mixers of the finished product.

To remove solids, the suspension is filtered through four layers of gauze. The bowl is covered with a lid.

- Setting to "type".

At the end of the dispersion, and if the degree of milling corresponds to the requirements of TU, the operation "setting on the type." The bowl with the suspension is moved under the dissolver. Suspension from the bowl can be pumped to the finished product mixer.

The dissolver stirrer is turned on and the prescription amount of Uralkid varnish and desiccant, as well as an anti-crater additive, are loaded into the bowl. Stirred for 15 minutes and determine the viscosity.

If the viscosity does not meet the requirements of TU, the enamel is diluted with white spirit. After each solvent charge, the suspension is stirred for 15-20 minutes.

When bringing the enamel color to normal or tinting the bases, the tinting pastes stored in plastic containers are weighed on a scale and loaded into a mixer or bowl under the dissolver. After each loading of the paste, stirring is carried out for 20 minutes until the suspension is completely uniform. Color control is carried out by comparing the dried sample with a reference in a light cabinet.

If the indicators are consistent, methyl ethyl ketoxime is added. Methyl ethyl ketoxime is mixed with enamel for 15-20 minutes, after which an OTC sample is transferred to re-control the viscosity. When the viscosity is consistent, the enamel is packed in a container.

Table 1 presents the specific conditions for the implementation of the method according to the invention for example, the preparation of enamel bright green.

Table 2 presents the characteristics of the components used in the implementation of the method of the invention.

Tables 3-4 show examples of alkyd-urethane enamels obtained by the method of the invention.

Table 5 shows the main properties of alkyd-urethane enamels obtained by the method according to the invention.

As follows from the data presented in tables 3-5, the claimed method according to the invention receive alkyd-urethane enamels of various colors with high physico-chemical and physico-mechanical, as well as protective properties, which allows them to be used in various industries: in construction in mechanical engineering.

Thus, the technical result of the claimed group of inventions is to provide the following characteristics: quick drying and stable gloss upon drying, high covering ability, economy, versatility - the enamel obtained by the proposed method is equally well suited for painting new and repairing previously painted surfaces. During storage, the enamel does not exfoliate, does not form a surface film and precipitate, is highly technological when applied, which is achieved due to the combination and sequence of introducing the components necessary for obtaining enamel developed in the invention into the alkyd-urethane composition, including the sequence of introducing pigment additives, tinting pastes and introducing anti-film additives with mandatory additional mixing of the suspension after each introduction of an additional additive or a new portion of any component, and akzhe developed inventive technology techniques and mixing components at the input parameters and results recommending changes stirrer speed and degree of grinding at an intermediate stage of production of enamel according to the claimed method.

Claims (10)

1. The method of producing alkyd-urethane enamel, characterized in that it includes the possible preliminary preparation of the individual starting components, their dosage, preparation of the semi-finished enamel by combining alkyd pentaphthalic varnish with a dispersant, an organic solvent and a rheological additive with stirring at a speed of 300-500 rpm, subsequent introduction into the resulting mixture of loose pigment components and, if necessary, a filler with their preliminary dispersion with stirring at a higher speed about 1000 rpm until a homogeneous suspension is obtained, further dispersing the semi-finished product until the desired degree of milling is achieved, then introducing alkyd-urethane varnish into it with stirring, and, if necessary, anti-crater additive and desiccant, and then introducing pigment tinting paste, mixing until complete homogeneity of the suspension and the introduction of anti-film additives. 2. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the preliminary preparation of the used rheological additive of the benton type is carried out by preparing a paste consisting of benton and white spirit, and its subsequent activation with acetone or ethyl alcohol or isopropyl alcohol. 3. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the preliminary preparation of anti-crater additives is carried out, preferably by preparing a 0.9-1.1% solution of polymethylsiloxane liquid in xylene. 4. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the preliminary preparation of pigment tinting paste of a certain color scheme, having a color, for example, window gray or gray basalt, or bright green, or ruby red, or signal -red, or deep black. 5. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the preliminary dispersion is carried out until a viscosity of 100-120 s according to B3-4 is achieved. 6. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the preliminary dispersion is carried out for 30-40 minutes 7. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the dispersion of the semi-finished product is carried out at a temperature of 60 ° C. 8. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the dispersion of the semi-finished product is carried out to a milling degree of not more than 25 microns. 9. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the dispersion of the semi-finished product is carried out to a milling degree of not more than 30 microns. 10. The method of producing alkyd-urethane enamel according to claim 1, characterized in that the dispersion of the semi-finished product is carried out to a milling degree of not more than 50 microns.