CN114989707B

CN114989707B - Polyurea coatings

Info

Publication number: CN114989707B
Application number: CN202210199483.7A
Authority: CN
Inventors: 王书元; 叶卫
Original assignee: Shenzhen Brilliant Technology Co ltd
Current assignee: Shenzhen Brilliant Technology Co ltd
Priority date: 2022-03-02
Filing date: 2022-03-02
Publication date: 2024-02-09
Anticipated expiration: 2042-03-02
Also published as: CN114989707A

Abstract

The present invention provides a polyurea coating comprising: 12-14% by weight of a diisocyanate trimer; 2-4% by weight of a component A solvent; polyaspartic acid ester, 8-14 wt%; 1 to 3% by weight of an HDI trimer type urethane component; a silica-based inorganic powder having a fineness of 200 mesh or more, of more than 45 wt%; 15-25% by weight of pigment; 2-8% by weight of a plasticizer; 2-8% of component B solvent. The present invention also provides another polyurea coating comprising: 12-14% by weight of a diisocyanate trimer; a component A solvent in an amount of 10 to 30 wt%; polyaspartic acid ester, 8-14 wt%; 1 to 3% by weight of an HDI trimer type urethane component; 0-55 wt% of a silica-based inorganic powder having a fineness of 200 mesh or more; pigment, 0-55%; 0-8% by weight of a plasticizer; and 10-40 wt% of component B solvent.

Description

Polyurea coatings

Technical Field

The invention belongs to the field of polyurea coatings. In particular, the present invention relates to a polyurea coating, more particularly, the present invention relates to a slow polyurea coating.

Background

Polyurea coatings have been widely used in various fields such as automobile industry, ship industry, building industry, etc. due to advantages of fast curing, high solid content, moisture resistance, excellent physical and chemical properties, etc. However, with the continuous expansion of application scenes, the popularization and application of polyurea coatings are gradually affected by the rapid curing reaction.

For conventional polyurea coatings, such as spray-applied polyurea elastomers (SPUA), the gel time is about 5 seconds, so that the wettability to the substrate is poor due to concentrated heat release and other factors, and the adhesive force is reduced, the interlayer bonding is poor, and the appearance problems such as orange peel, pinholes and the like are caused. In addition, spray polyurea elastomers (SPUA) are typically applied with polyurea coatings using high temperature, high pressure, impact mixing equipment, which is expensive, bulky, and not suitable for small area repairs.

Polyurea coatings having a gel time of greater than 1 hour are now commonly referred to in the industry as slow-reacting polyurea coatings (which may also be referred to simply as slow polyureas). The main focus of reducing the reaction rate of polyurea systems is now roughly in two ways: on the one hand, novel chain extenders and on the other hand, novel prepolymers are used. However, despite attempts to use improved prepolymers, the gel time of the polyurea did not exceed 30 minutes. For the chain extender, the presence of polyaspartic acid esters extends the gel time of the polyurea to more than ten minutes.

With years of development and research, the gel time of polyurea coatings can be prolonged to one hour by using polyaspartic acid ester as a chain extender, and low-solid-content polyurea coatings can be reported to reach 2 hours. However, for polyurea coatings with higher solids content, it has not been reported that the gel time of the polyurea coating is extended to more than one hour with polyaspartic acid esters.

Although the gel time of polyurea coatings with higher solids content is already close to one hour, there are problems of complex equipment (special equipment is required), complex operation, and insufficient operation time during anticorrosive coating, compared to the conventional coating process.

In this regard, the invention provides a new polyurea coating and a preparation method thereof, and further solves some key technical problems existing in the art.

Disclosure of Invention

In a first aspect of the present invention, there is provided a polyurea coating comprising or consisting of:

wherein the polyaspartic acid ester has a structure represented by the following formula 1:

in formula 1, R is C _1-4 Straight or branched alkyl, X is C _1-15 An alkylene group;

the HDI trimer type carbamate component is carbamate formed by HDI trimer and monohydroxy compound, and is selected from one or more of octadecyl methylene triurea methyl tricarbamate, octadecyl methylene triurea diethylene glycol diethyl ether ester, octadecyl methylene triurea dipropylene glycol monomethyl ether ester, octadecyl methylene triurea 1, 4-butanediol methyl ether ester, octadecyl methylene triurea trioxane formate siloxane ester and combination thereof;

The diisocyanate trimer has a structure represented by the following general formula 2:

in formula 2, R is C _3-10 A linear chain of alkylene groups which are bonded to each other,

the component A solvent is selected from acetone, ethyl acetate, dipropylene glycol dimethyl ether and a combination thereof,

the component B solvent is selected from ethanol, methylal, ethyl acetate, dipropylene glycol dimethyl ether, N-methylpyrrolidone and components thereof,

wherein weight percent is based on the weight of the polyurea coating.

In one embodiment, the pigment is selected from titanium dioxide-based pigments, carbon-based pigments, iron oxide-based pigments, cadmium selenide sulfide-based red-yellow pigments, lead chromate-based yellow pigments, ultramarine-based pigments. In another embodiment, the pigment is selected from titanium dioxide, carbon black, iron oxide red, cadmium selenide sulfide, lead chromate, ultramarine.

In one embodiment, in formula 1, R is ethyl and X is a structure represented by formula 3 below:

in one embodiment, in formula 2, R is a hexylene group.

In one embodiment, the component a solvent is acetone, dipropylene glycol dimethyl ether, ethyl acetate, or a combination thereof, 3.23 wt%. In another embodiment, the component b solvent is 3.23 wt.% ethanol, 2.77 wt.% methylal, or 2-4 wt.% of a mixture of one or more of ethyl acetate, dipropylene glycol dibenzoate, and N-methylpyrrolidone in any ratio. In yet another embodiment, the component B solvent is a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether and N-methylpyrrolidone in any proportion, 2 to 4% by weight.

In one embodiment, the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane. In another embodiment, the silica-based inorganic powder is a 200-2000 mesh fineness silica-based inorganic powder, a nanoscale silica-based inorganic powder, or a combination thereof. In yet another embodiment, the silica-based inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon, silica sand, and combinations thereof. In another embodiment, the inorganic powder is present in an amount of at least 45.20 wt.%.

In one embodiment, the plasticizer is silicone, liquid paraffin, dipropylene glycol dibenzoate, or a combination thereof. In another embodiment, the silicone resin comprises: any combination of one or more of methyl silicone oil, hydroxyl silicone oil, amino silicone oil, hydrocarbon-based modified silicone oil, styryl modified silicone oil, polyether modified silicone oil, polyester modified silicone oil or a combination thereof.

In a second aspect of the invention, there is provided another polyurea coating comprising or consisting of the following components:

wherein the weight% is based on the weight of the polyurea coating and the total weight of the inorganic powder and the pigment is not less than 55 weight%.

in one embodiment, in formula 2, R is a hexylene group.

In one embodiment, the component B solvent is ethanol, methylal or a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether and N-methylpyrrolidone in any proportion. In another embodiment, the component B solvent is ethanol, methylal, and a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether and N-methylpyrrolidone in any proportion.

In one embodiment, the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane. In another embodiment, the silica-based inorganic powder is a 200-2000 mesh fineness silica-based inorganic powder, a nanoscale silica-based inorganic powder, or a combination thereof. In yet another embodiment, the silica-based inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon, silica sand, and combinations thereof.

Drawings

The drawings are provided below to further describe embodiments of the present invention and effects thereof, but are shown only for the purpose of allowing those skilled in the art to better understand the disclosure of the present invention and are not intended to limit the scope of the present invention.

FIG. 1 is a plot of the impedance modulus of four different coatings against simulated seawater time, where (a) of FIG. 1 is a plot of the four coatings, and (b) of FIG. 1 is an enlarged illustration of the plot outlined by the circles in (a) of FIG. 1; and

fig. 2 is a photograph of the surface corrosion condition of working electrodes coated with four different paints, where fig. 2 (a) is the corrosion condition of working electrodes coated with an epoxy paint, fig. 2 (b) is the corrosion condition of working electrodes coated with an acrylic polyurethane, fig. 2 (c) is the corrosion condition of working electrodes coated with a polyester, and fig. 2 (d) is the corrosion condition of working electrodes coated with the polyurea of the present invention.

Detailed Description

Hereinafter, the present invention will be further described according to specific embodiments. However, the specific embodiments are set forth for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art will recognize that the specific features set forth in any of the embodiments below may be used in any other embodiment or may be combined with other specific features in other embodiments without departing from the spirit of the invention.

General definition

The technical terms given herein may be construed using the definitions set forth below, and may also be construed using meanings commonly used in the art, if not explicitly stated. The definitions given herein control when the definitions set forth below deviate from the usual meaning in the art.

As used herein, polyurea coatings refer to coatings having a polyamine content of greater than 80% in the backbone of the film-forming resin of the coating, wherein the backbone of the resin is a compound containing urea groups.

By slow polyurea coating is meant herein a coating that has a gel time of greater than 1 hour at ambient temperature (25.+ -. 0.2 ℃). In this context, the curing of polyurea coatings is achieved mainly by the crosslinking reaction of the curing agent with the chain extender.

As used herein, a high solids coating is defined as: the solid component content of the film forming coating is more than 75 weight percent of the coating.

As used herein, a low viscosity coating is defined as: according to the measurement method specified in GB1723-79, the viscosity of a coating is measured at a temperature of 25.+ -. 0.2 ℃ using a coating-4 viscometer, and when the viscosity reaches 20-30 seconds, the coating can be regarded as a low viscosity coating. In short, the viscosity of the coating can be measured by the following method: in the measurement, the viscometer is regulated to be in a horizontal state at the temperature of 25+/-0.2 ℃, a 150ml beaker is placed under the viscometer, a ball valve is used for blocking a discharge spout hole, the viscometer is filled with the paint, the paint flows out, a stopwatch is started for timing at the same time until the flow wire of the paint is interrupted, the timing is stopped immediately, the time is the conditional viscosity of the glue solution, the measurement is repeated three times, and the error is not more than 3% of the average value.

As used herein, alkyl refers to a straight chain, branched, or cyclic or a combination thereof saturated aliphatic hydrocarbon monovalent group, and alkylene refers to a straight chain, branched, or cyclic or a combination thereof saturated aliphatic hydrocarbon divalent group. Carbon number C used in describing alkyl or alkylene groups _1-15 It may be interpreted that the group contains 1 to 15 carbon atoms, or any number in the range of 1 to 15 carbon atoms, for example 3, 5, 10 carbon atoms. Other carbon number (e.g. C _1-4 ) And can be interpreted identically. Examples of alkyl groups include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, tert-butyl, cyclobutyl, n-pentyl, neopentyl, cyclopentyl, n-hexyl, cyclohexyl and the like.

In this context, if the temperature is not particularly limited, it means that the operation is carried out at ambient temperature (25.+ -. 0.2 ℃ C.).

Polyurea coatings

In one embodiment, the polyurea coating comprises or consists of the following components:

in one embodiment, the polyaspartic acid ester has a structure represented by the following formula 1:

in formula 1, R is C _1-4 Straight or branched alkyl, X is C _1-15 An alkylene group. In another embodiment, R may be methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, and the like. In yet another embodiment, X is a linear alkylene, branched alkylene, cyclic alkylene, or combination thereof having a total carbon number of 15 or less, such as methyl or ethyl substituted with an alkanyl or cycloalkyl group. In further embodiments, the polyaspartic acid urethane is present in an amount of 8 wt.%, 10 wt.%, 12 wt.%, or 14 wt.%, wherein the wt.% is based on the weight of the polyurea coating. In one embodiment, in formula 1, X is a structure represented by the following formula 3:

In one embodiment, the HDI trimeric urethane component may be selected from one or more of the group consisting of methyl stearyl methylene triurea tricarbamate, diethylene glycol diethyl stearyl methylene triurea tricarbamate, dipropylene glycol monomethyl ether stearyl methylene triurea tricarbamate, 1, 4-butanediol methyl ether stearyl methylene triurea tricarbamate, and combinations thereof. In another embodiment, the HDI trimeric urethane component may be present in an amount of 1 to 3 wt%, for example 1 wt%, 2 wt% or 3 wt%, wherein the wt% are based on the weight of the polyurea coating. In one embodiment, the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane. The compatibility of each component of the coating can be effectively improved by adopting the octadecyl methylene triurea tricarbamic silicon oxide, and the phenomenon of surface shrinkage of the coating is prevented.

The molecular formula and the synthesis process of the methyl octadecyl methylene triurea tricarbamic acid ester are shown as follows:

the molecular formula and the synthesis process of the octadecyl methylene triurea tricarbamic acid siloxane ester are shown as follows:

Wherein n is 1 to 5

The molecular formula and the synthesis process of the octadecyl methylene triurea tricarbamic diethylene glycol diethyl ether ester are shown as follows:

the molecular formula and the synthesis process of the dipropylene glycol monomethyl ether ester of the octadecyl methylene triurea tricarbamic acid are shown as follows:

the molecular formula and the synthesis process of the octadecyl methylene triurea tricarbamic acid 1, 4-butanediol methyl ether ester are shown as follows:

in one embodiment, the diisocyanate trimer has a structure represented by the following formula 2:

in formula 2, R is C _3-10 Linear alkylene groups such as propylene, butylene, hexylene, and the like.

In yet another embodiment, in formula 2, R is a hexylene group. In another embodiment, the diisocyanate trimer is present in an amount of 12 wt.%, 13 wt.%, or 14 wt.%, where the wt.% is based on the weight of the polyurea coating.

The inventor of the scheme finds that the reaction kinetics of the polyaspartic acid polyurea is greatly influenced by the concentration through the analysis of the chemical reaction kinetics of the polyaspartic acid polyurea. According to the characteristics, the slow polyurea coating with the gel time longer than three hours is obtained through the concentration selection of the polyaspartic acid ester chain extender and the isocyanate component and the specific proportion of the polyaspartic acid ester chain extender and other components, and meanwhile, the slow polyurea coating can also keep higher solid content and lower viscosity.

As shown in the examples below, such a formulation was found to enable a gel time of at least 3-5 hours for polyurea coatings during specific operations, if by means of the addition of diluents or the like, a coating operation time of more than 24 hours could be achieved and the coating effect could be ensured unchanged. At present, in the field experiment process, the coating operation time can be longer than 3 days without obviously influencing the coating effect.

In one embodiment, the component a solvent may be selected from the group consisting of acetone, ethyl acetate, dipropylene glycol dimethyl ether, and combinations thereof. In another embodiment, the component B solvent may be selected from the group consisting of ethanol, methylal, ethyl acetate, dipropylene glycol dimethyl ether, N-methylpyrrolidone, and components thereof. In one embodiment, the component b solvent is 3.23 wt% ethanol, 2.77 wt% methylal. In another embodiment, the component B solvent is 3.23 wt.% ethanol, 2.77 wt.% methylal, and 2-4 wt.% of a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether, and N-methylpyrrolidone in any ratio.

In one embodiment, the pigment is selected from titanium dioxide-based pigments, carbon-based pigments, iron oxide-based pigments, cadmium selenide sulfide-based red-yellow pigments, lead chromate-based yellow pigments, ultramarine-based pigments. In another embodiment, the pigment is selected from titanium dioxide, carbon black, iron oxide red, cadmium selenide sulfide, lead chromate, ultramarine. In one embodiment, the pigment may be present in an amount of 15 to 25 wt.%, for example 18 wt.%, 20 wt.%, 22 wt.%, etc.

In another embodiment, the silica-based inorganic powder is a 200-2000 mesh fineness silica-based inorganic powder, a nanoscale silica-based inorganic powder, or a combination thereof. In yet another embodiment, the silica-based inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon, silica sand, and combinations thereof. In another embodiment, the inorganic powder is present in an amount of at least 45.20 wt.%. The polyurea coating of the present invention can maintain a lower viscosity and longer gel time while containing a higher solids content.

The inventors of the present application found that silica-based inorganic powders can exert a good effect in terms of extending the gel time, however, it should be noted that the inorganic powders have a water content of less than 0.5%, otherwise uneven dispersion may occur, and small particle-like defects may be generated on the surface of the coating, which may affect the gloss of the coating surface. For the polyurea coating according to the invention, the above inorganic powders can be used such that the solids content of the polyurea coating exceeds 70% by weight, even 90% by weight, for example, in the polyurea coating of the above formulation, the solids content can be up to 90.77% by weight. The polyurea coating of the above formulation is an environmentally friendly high solids coating that contains little solvent component, has little volatiles during actual operation, and is also capable of meeting the requirements for high solids.

In one embodiment, the plasticizer is silicone, liquid paraffin, dipropylene glycol dibenzoate, or a combination thereof. In another embodiment, the silicone resin comprises: any combination of one or more of methyl silicone oil, hydroxyl silicone oil, amino silicone oil, hydrocarbon-based modified silicone oil, styryl modified silicone oil, polyether modified silicone oil, polyester modified silicone oil or a combination thereof. The viscosity of the polyurea coating can be effectively reduced by the cooperation of the plasticizer and the solvent, so that the polyurea coating can be coated by adopting conventional equipment and conventional coating technology, and the complex special equipment is avoided.

In the polyurea coatings above, other solvents disclosed herein may also be selected depending on the application of the polyurea coating. For example, when the use environment temperature is higher than 60 ℃, dipropylene glycol dimethyl ether (component A) and diethylene glycol monoethyl ether (component B) can be selected to be used; if the odor removal is required, diethylene glycol dimethyl ether (component A and component B) can be selected, but the surface drying and the actual drying speed are low; when the concrete base surface is used as a bottom coating, dipropylene glycol dimethyl ether (component B), chlorinated paraffin (component B), N-methylpyrrolidone (component B) or tetrachloroethylene (component A) can be selected. In addition, if raw materials such as acetone and methylal are not easily purchased, ethyl acetate (component a and component b) may be selected for use, but because of its high taste, it is necessary to avoid use in an environment where odor removal is required.

In the polyurea coatings described hereinabove, the polyamine content in the backbone of the coating film-forming resin is approximately 100% and thus meets relevant regulations for polyurea coatings, such as the classification and definition of polyurea and polyurethane coatings by the american society for development of polyureas: when the polyamine content in the system is greater than 80%, the material is referred to as a polyurea coating; when the polyol content in the system is greater than 80%, the material is referred to as a polyurethane coating; and the materials are collectively referred to as polyurea/polyurethane hybrids or blends where the polyamine and polyol content of the system is intermediate.

The polyurea coatings provided herein can still achieve viscosities of 20-30 seconds (measured using a coating-4 viscometer using the methods described above) at high solids levels. In practice, the polyurea coatings provided herein have a gel time of greater than 3 hours and a paint operation time of greater than 1 hour (typically 1-3 hours, i.e., during which time conventional paint equipment and conventional paint process operations may be employed), such as if diluted with a diluent (e.g., ethanol) (e.g., at a rate of one fifteenth of the diluent added per hour), the paint operation time may be greater than 5 hours, while the paint effect remains unchanged. According to current field experience, if 15-20 wt% ethanol is added at one time or in portions, the coating operation time can be prolonged to more than 24 hours. The method can be diluted by adopting non-benzene solvents such as ethanol and the like, and has remarkable advantages in the aspects of protection of constructors, environmental protection and the like.

Based on the properties, the polyurea coating provided herein can be coated by adopting conventional coating equipment according to conventional coating process requirements, and can fully infiltrate a base surface due to relatively long gel time and low viscosity, and no destructive stress exists at an interface and inside the coating, so that bubbling, pinholes, shrinkage cracking and other phenomena can be avoided. Furthermore, the polyurea coatings provided herein can produce thin coatings with dry film thicknesses of only 15-20 microns, whereas typical high solids coatings generally have dry film thicknesses greater than 100 microns, only a few of which can achieve dry film thicknesses of around 80 microns.

In addition, in the case of conventional polyurea coating materials, since isocyanate groups (-NCO) and liquid amines are toxic, odorous and irritating substances, it is necessary for the constructor to wear gas masks, goggles, rubber gloves, protective clothing, protective shoes, etc., and to stand at the tuyere. Only if the coating is fully reacted to fully polymerize and form macromolecular polyurea elastomer, and the polyurea coating completely meets the environmental protection requirement under the condition of no free monomer. The polyurea coating provided by the invention belongs to an odor-free slow-release polyurea coating due to specific formula selection and proportion, is basically odorless, has no harmful effect on the environment and people during construction, i.e. the coating product is environment-friendly and the product construction is environment-friendly.

the HDI trimer type carbamate component is selected from one or more of methyl stearyl methylene triurea tricarbamate, diethylene glycol diethyl ether stearyl methylene triurea tricarbamate, dipropylene glycol monomethyl ether stearyl methylene triurea tricarbamate, 1, 4-butanediol methyl ether stearyl methylene triurea tricarbamate, stearyl methylene triurea tricarbamate and a combination thereof;

wherein weight% is based on the weight of the polyurea coating and the total weight of the inorganic powder and the pigment is not less than 55 weight%, and typically not more than 75 weight%.

The above descriptions of pigments, formula 1, formula 2, a component solvent, an HDI trimer-type urethane component, a silica-based inorganic powder and a plasticizer are all applicable here, and thus are not repeated. The polyurea resin contains a higher solvent component and is therefore easier to implement and handle. Although the solids content of the polyurea coating is generally not higher than 75% by weight, slow polyurea coatings having long gel times and long coating run times remain.

Method for producing polyurea coatings

In one embodiment, a method of preparing a polyurea coating includes: uniformly mixing the diisocyanate trimer represented by the general formula 2 with the solvent of the first component (i.e., the mixed system is clear after standing, the same applies below), thereby obtaining the first component; uniformly mixing an HDI trimer type urethane component, polyaspartic acid urethane and a plasticizer, uniformly mixing the obtained mixture with inorganic powder based on silicon dioxide with the fineness of more than 200 meshes, and then uniformly mixing the obtained mixture with a component B solvent, thereby obtaining a component B; mixing the first component with the second component, thereby obtaining the polyurea coating.

In this embodiment, the liquid component must be thoroughly mixed before the inorganic powder is finally added to the mixture to prepare the second component. If various unmixed liquid components are added into the inorganic powder, the prepared component B is easy to generate a sinking and caking phenomenon. In addition, the prepared component B is placed for more than 5 days, and layering phenomenon can possibly occur, and the component B is required to be stirred again uniformly and then used without being prepared again. In this regard, the storage period of the component A and the component B is half a year, and before the components are mixed, the components are only required to be uniformly stirred respectively, so that the final performance is not affected.

In one embodiment, the inorganic powder has a moisture content of less than 0.5% prior to addition of the inorganic powder, the benefits of which are described above and are not described in detail herein. In addition, after methylal was added and mixed, the amount of methylal loss was measured, and the worn methylal was replenished. The method is characterized in that methylal is extremely volatile, loss occurs when the component B is stirred, the loss is required to be measured, the loss is complemented in the later period of the component B preparation, and the concentration of each component of the coating is not influenced. In addition, ethanol cannot be used as a solvent for the component a because it reacts with hexamethylene diisocyanate trimer (abbreviated as HDI trimer).

In a further embodiment, a method of preparing a polyurea coating includes: uniformly mixing hexamethylene diisocyanate trimer and hydroxyl polyester (for example, with molecular weight of 2000) according to a certain proportion for addition reaction, thereby obtaining diisocyanate represented by a general formula 2 as a chain extender, adding one or a mixture of three of acetone, ethyl acetate or dipropylene glycol dimethyl ether according to any proportion, and uniformly mixing to obtain a component A; uniformly mixing an HDI trimer type urethane component, polyaspartic acid urethane and a plasticizer, uniformly mixing the obtained mixture with inorganic powder based on silicon dioxide with the fineness of more than 200 meshes, and then uniformly mixing the obtained mixture with a component B solvent, thereby obtaining a component B; mixing the first component with the second component, thereby obtaining the polyurea coating.

In one embodiment, a method of preparing a polyurea coating includes: the composition is obtained by uniformly mixing an HDI trimer-type urethane component, polyaspartic acid ester and a plasticizer, uniformly mixing the obtained mixture with a silica-based inorganic powder having a fineness of 200 mesh or more and a pigment, and then uniformly mixing the obtained mixture with a composition b solvent. Mixing the component B with the component B, thereby obtaining the polyurea coating.

Use and application of polyurea coating

The polyurea coating provided herein can be applied without special polyurea coating equipment due to long gel time and low viscosity, and effectively avoids damaging stress of the polyurea coating due to fast curing. For example, the components A and B can be mixed and stirred uniformly in proportion at room temperature (the stirring is recommended to be carried out for 5 to 8 minutes by a stirrer with the rotating speed of 300 to 500 revolutions per minute), and then the spraying and coating can be carried out by using conventional air spraying equipment under the air pressure condition of 3 to 8 kilograms per square centimeter; and spraying and coating by using a universal airless spraying device under the condition of gas pressure of 5-12 kg/square cm.

As an example, the polyurea coatings provided herein have passed detection and validation in the us KTA laboratory in 2018 and are allowed to be used for container protection. In the same year, the polyurea coating provided herein has been subjected to a plurality of spraying experiments on a production site in the south, and can completely meet the process use requirements of a container coating spraying production line. In field tests, the polyurea coatings provided herein can be matched to conventional coating processes due to low viscosity and long gel time, thereby achieving polyurea coating normalization.

The polyurea coating provided by the invention has good environmental protection performance, simple and convenient construction, physical and chemical properties far superior to those of the existing water-based coating, and can be used in the building industry, the metal protection industry and the furniture industry.

Examples

Hereinafter, the present invention will be described in further detail with reference to specific examples, but the scope of the present invention is not limited thereto. The reagents used in the examples are all commercially available and, in particular:

the polyaspartic acid ester is F-520 of the Zhuhai Feiyang New Material Co., ltd, the relative molecular weight is 580, and the NH equivalent is 290g/mol; the preparation method of the octadecyl methylene triurea tricarbamic acid silicone ester is as a self-made product; the inorganic pigment is R930 titanium pigment produced by Japanese Kagaku Co; the inorganic powder is quartz sand with the fineness of 800 meshes produced in China; the plasticizer is domestic BD-3310 polyester modified polydimethylsiloxane; the HDI trimer is produced by Wanhua corporation in China and has the model number of HT-100; the rest solvents are all industrial solvents.

Hereinafter, "parts" means parts by weight unless otherwise specified.

Preparation of HDI trimer-type urethane component:

HDI trimer was prepared as 1:3, uniformly stirring, and standing for seven days to obtain the octadecyl methylene triurea tricarbamic acid silicone ester, wherein the specific reaction is as follows, and n is 1-5:

Similarly, methyl octadecene triurea tricarbamate is produced by reacting an HDI trimer with methanol, e.g., by reacting the HDI trimer with 1:3, adding the mixture into a solvent containing methanol in a molar equivalent ratio, uniformly stirring, and standing for seven days; the octadecyl methylene triurea tricarbamic acid diethylene glycol diethyl ether ester is generated by reacting an HDI trimer with diethylene glycol diethyl ether, for example, the HDI trimer is added into a solvent containing diethylene glycol diethyl ether according to a certain equivalent ratio, and the mixture is stirred uniformly and stands for seven days; the octadecyl methylene triurea tricarbamic acid dipropylene glycol monomethyl ether ester is generated by the reaction of an HDI trimer and dipropylene glycol monomethyl ether, for example, the HDI trimer is added into a solvent containing dipropylene glycol monomethyl ether according to a certain equivalent ratio, and the solvent is stirred uniformly and stands for seven days; the 1, 4-butanediol methyl ether ester of the octadecyl methylene triurea tricarbamic acid is generated by the reaction of an HDI trimer and 1, 4-butanediol methyl ether, for example, the HDI trimer is added into a solvent containing the 1, 4-butanediol methyl ether according to a certain equivalent ratio, and the solvent is stirred uniformly and stands for seven days.

Example 1

At room temperature, 137 parts of HDI trimer and 35 parts of acetone are mixed together, and the mixture is fully and uniformly stirred by a dispersing stirrer (the mixture is clear after standing at the moment), so that the component A of the polyurea coating is obtained, and the polyurea coating is stored in a sealing way.

After 26 parts of octadecyl methylene triurea tricarbamic acid silicone ester, 141 parts of polyaspartic acid ester F-520 and 70 parts of plasticizer BD-3310 are uniformly mixed, 490 parts of 800-mesh quartz sand and 120 parts of R930 titanium pigment are added, a three-roll mill is used for fully and uniformly grinding, 847 parts of color paste of the polyurea coating is prepared, 35 parts of ethanol and 30 parts of methylal are added, and the mixture is fully and uniformly stirred by a dispersing stirrer, so that the component B of the slow polyurea coating is obtained, and the slow polyurea coating is stored in a sealing way.

Before coating, the coating comprises the following components: component b = 1:5.3, mixing and stirring uniformly, and coating. The formulation of the polyurea coating of example 1 is shown in table 1 below.

Table 1: formulation of polyurea coating of example 1

Example 2

At room temperature, 137 parts of HDI trimer and 35 parts of dipropylene glycol dimethyl ether are mixed together, and the mixture is fully and uniformly stirred by a dispersing stirrer (the mixture is clear after standing at the moment), so that the component A of the polyurea coating is obtained, and the polyurea coating is stored in a sealing way.

26 parts of octadecyl methylene triurea tricarbamic acid silicone ester, 35 parts of dipropylene glycol dimethyl ether, 141 parts of polyaspartic acid ester F-520 and 10 parts of plasticizer BD-3310 are uniformly mixed, 650 parts of 800-mesh quartz sand and 150 parts of R930 titanium dioxide are added, a three-roll mill is used for fully and uniformly grinding, 1012 parts of color paste of the polyurea coating is prepared, 35 parts of ethanol and 35 parts of dipropylene glycol dimethyl ether are added, and the mixture is fully and uniformly stirred by a dispersing stirrer, so that the ethylene component of the slow polyurea coating is obtained, and the slow polyurea coating is stored in a sealing manner.

Before coating, the coating comprises the following components: component b = 1:5.22, and uniformly stirring to obtain the final product. The formulation of the polyurea coating of example 2 is shown in table 2 below, and this coating is a matt type coating.

Table 2: formulation of polyurea coating of example 2

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Example 3

26 parts of octadecyl methylene triurea tricarbamic acid silicone ester, 35 parts of dipropylene glycol dimethyl ether, 141 parts of polyaspartic acid ester F-520 and 10 parts of plasticizer BD-3310 are uniformly mixed, 650 parts of 1250-mesh glass powder and 150 parts of R930 titanium dioxide are added, a three-roll mill is used for fully and uniformly grinding, 1012 parts of color paste of the polyurea coating is prepared, 35 parts of ethanol and 35 parts of dipropylene glycol dimethyl ether are added, and the mixture is fully and uniformly stirred by a dispersing stirrer, so that the ethylene component of the slow polyurea coating is obtained, and the slow polyurea coating is stored in a sealing way.

Before coating, the coating comprises the following components: component b = 1:5.22, and uniformly stirring to obtain the final product. The formulation of the polyurea coating of example 3 is shown in Table 3 below, and the coating is a surface-slip coating.

Table 3: formulation of polyurea coating of example 3

Example 4

26 parts of octadecyl methylene triurea tricarbamic acid silicone ester, 35 parts of dipropylene glycol dimethyl ether, 141 parts of polyaspartic acid ester F-520 and 10 parts of plasticizer BD-3310 are uniformly mixed, 650 parts of 3-150 micrometer glass beads and 150 parts of R930 titanium pigment are added, the mixture is fully and uniformly stirred by a dispersing stirrer to prepare 1012 parts of color paste of the polyurea coating, 35 parts of ethanol and 35 parts of dipropylene glycol dimethyl ether are added, the mixture is fully and uniformly stirred by the dispersing stirrer, and thus the second component of the slow polyurea coating is obtained, and the slow polyurea coating is stored in a sealing way.

Before coating, the coating comprises the following components: component b = 1:5.22, and uniformly stirring to obtain the final product. The formulation of the polyurea coating of example 4 is shown in table 4 below, and this coating can be used as a heat-insulating type coating.

Table 4: formulation of polyurea coating of example 4

Example 5

217 parts of HDI trimer and 160 parts of ethyl acetate are mixed together at room temperature, and the mixture is fully and uniformly stirred by a dispersing stirrer (the mixture is clear after standing at the moment), so that the component A of the polyurea coating is obtained, and the polyurea coating is stored in a sealing way.

Uniformly mixing 26 parts of octadecyl methylene triurea tricarbamic acid silicone ester, 243 parts of polyaspartic acid ester F-520 and 70 parts of plasticizer BD-3310, adding 350R930 titanium pigment, fully and uniformly grinding by a three-roller machine to obtain 689 parts of color paste of the polyurea coating, adding 450 parts of ethanol and 350 parts of dipropylene glycol dimethyl ether, fully and uniformly stirring by a dispersing stirrer, thus obtaining the component B of the slow polyurea coating, and sealing and storing.

Before coating, the coating comprises the following components: component b = 1:3.95, and uniformly stirring, thus coating. Other types of polyurea coatings the formulation of example 5 is shown in table 5 below, and this coating is a thin, medium gloss coating.

Table 5: formulations for other types of polyurea coatings

Comparative example 1

Polyurea coatings were prepared in the same manner as in example 1, except that 800 mesh quartz sand was not used but 800 mesh kaolin was used. The formulation of the polyurea coating of comparative example 1 is shown in Table 6 below, but after the A and B components were obtained separately, the A components were formulated: component b = 1:5.3, and stirring uniformly, wherein the viscosity of the paint is extremely high, and the paint cannot be coated by a conventional method.

Table 6: formulation of polyurea coating of comparative example 1

Comparative example 2

A polyurea coating was prepared in the same manner as in example 1, except that octadecyl methylene triurea tricarbamic acid silicone ester was not used, with plasticizer BD-3310, but with the other plasticizer (diisononyl phthalate DINP). The formulation of the polyurea coating of comparative example 2 is shown in Table 7 below, but after the A and B components were obtained separately, the A components were formulated: component b = 1:5.3, and uniformly stirring, wherein when the coating is sprayed on the surface of a substrate, shrinkage holes of the coating can occur, and the quality of the coating is greatly influenced.

Table 7: formulation of polyurea coating of comparative example 2

Numbering device	The components	Parts by weight	Weight content (%)
				1	F-520	141	13.01
2	R930 titanium dioxide	120	11.07
				3	800 mesh quartz sand	490	45.20
4	Ethanol	35	3.23
				5	DINP	96	8.86
6	Acetone (acetone)	35	3.23
				7	HT-100	137	12.64
8	Methylal (methylal)	30	2.77
				9	Totalizing	1084	100

Experimental example 1

Table 8 shows the test results of the polyurea coating obtained in example 1.

Table 8: parameters of polyurea coatings

As can be seen from the above, the inventors of the present application have studied the chemical reaction kinetics of polyaspartic polyurea, and have achieved excellent polyurea coating properties and ensured a relative balance between the various properties through specific component ratios.

Experimental example 2

Resistance experiments were performed on the polyurea coatings of the present invention in the university of martial arts electrochemical laboratory, and the test results are shown in fig. 1. Briefly, the working electrode surfaces were coated with four coatings and in a simulated seawater corrosion experiment, the impedance film values at the lowest frequency (10 millihertz) were plotted against soak time. Coatings No. 01 to 03 are respectively commercially available epoxy coating, acrylic polyurethane coating and polyester coating, and coating No. 04 is the polyurea coating of the present invention (example 1). In the whole experiment, other parameters are the same except that the materials of the coatings are different.

In this experiment, the lowest frequency (10 millihertz) mode of impedance can be considered as the resistance of the coating, and the resistance of all three coatings is progressively smaller except for the 01 # epoxy coating, which is too quickly saturated with salt water. This is related to the ability of the coating to block water penetration, and as brine permeates and swells, the resistance of the coating decreases. As can be seen from fig. 1, of the four coatings, the resistance to corrosion and corrosion of polyurea No. 04 is optimal, followed by polyester No. 03.

In addition, FIG. 2 shows a photograph of the surface corrosion condition of working electrodes coated with four different paints (the scribe area is the working electrode range, the area is 1.56cm ² ) Where (a) of fig. 2 is the corrosion condition of the working electrode coated with the epoxy mid-coat, (b) of fig. 2 is the corrosion condition of the working electrode coated with the acrylic polyurethane, (c) of fig. 2 is the corrosion condition of the working electrode coated with the polyester, and (d) of fig. 2 is the corrosion condition of the working electrode coated with the polyurea of the present invention. It can be seen from fig. 2 (d) that the working electrode coated with the polyurea of the present invention does not show corrosion spots, whereas fig. 2 (a) shows almost all corrosion, fig. 2 (b) shows large area edge corrosion and severe center corrosion, and fig. 2 (c) shows multiple corrosion spots.

Experimental example 3

The polyurea coatings of the present invention (example 1) were subjected to salt spray aging tests at the Guangdong province paint test center, according to GB/T1771-2007 determination of neutral salt spray resistance of paints and varnishes and tested using an L3022SST-9NL salt spray test box, the results of which are shown in Table 3 below.

Table 3: salt spray test results of polyurea coatings of the invention

From the above, the technical indexes of the polyurea reach or exceed the indexes of the existing general anti-corrosion paint. In this regard, it is considered that the slow polyurea of the present invention has a relatively long gel time, can sufficiently infiltrate the base surface, does not have destructive stress at the interface and in the interior of the paint, and has a great superiority in corrosion resistance.

Although a particular embodiment of the present invention has been described with reference to a particular embodiment, it should be understood that numerous modifications and changes may be made thereto by those skilled in the art without departing from the scope and spirit of the invention.

Claims

1. A polyurea coating comprising:

and the component A: 12-14% by weight of a diisocyanate trimer; 2-4% by weight of a component A solvent,

and the component B: 8-14% by weight of polyaspartic acid ester; 1-3 wt% of an HDI trimeric urethane component; greater than 45 weight percent of a silica-based inorganic powder having a fineness of 200-2000 mesh, a nanoscale silica-based inorganic powder, or a combination thereof; 15-25% by weight of a pigment; 2-8 wt% of a plasticizer; 2-8% by weight of a component B solvent,

the HDI trimer type carbamate component is selected from one or more of the following octadecyl methylene triurea methyl formate, octadecyl methylene triurea diethylene glycol diethyl ether ester, octadecyl methylene triurea dipropylene glycol monomethyl ether ester, octadecyl methylene triurea 1, 4-butanediol methyl ether ester, octadecyl methylene triurea silicone formate and the combination thereof, wherein n is 1-5,

the component B solvent is selected from ethanol, methylal, ethyl acetate, dipropylene glycol dimethyl ether, N-methylpyrrolidone and a combination thereof,

wherein weight percent is based on the weight of the polyurea coating.

2. The polyurea coating of claim 1, wherein the pigment is selected from the group consisting of titanium dioxide-based pigments, carbon-based pigments, iron oxide-based pigments, cadmium selenide sulfide-based red-yellow pigments, lead chromate-based yellow pigments, and ultramarine-based pigments.

3. The polyurea coating of claim 2, wherein the pigment is selected from the group consisting of titanium dioxide, carbon black, iron oxide red, cadmium selenide sulfide, lead chromate, and ultramarine.

4. The polyurea coating of claim 1, wherein in formula 1, R is ethyl and X is a structure represented by formula 3 below:

optionally, in formula 2, R is a hexylene group.

5. The polyurea coating of claim 1, wherein the solvent of component a is 3.23 wt% acetone, dipropylene glycol dimethyl ether, ethyl acetate, or a combination thereof, based on the total weight of the polyurea coating; and/or the number of the groups of groups,

The component B solvent is 3.23 weight percent of ethanol and 2.77 weight percent of methylal based on the total weight of the polyurea coating, and/or a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether and N-methyl pyrrolidone in any proportion.

6. The polyurea coating of claim 1, wherein the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane; and/or

The silica-based inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon black, quartz sand, and combinations thereof, the inorganic powder being present in an amount of at least 45.20 wt%; and/or

The plasticizer is a silicone, liquid paraffin, dipropylene glycol dibenzoate, or a combination thereof, optionally the silicone comprises: hydroxyl silicone oil, amino silicone oil, hydrocarbon-based modified silicone oil, styrene-based modified silicone oil, polyether-modified silicone oil, polyester-modified silicone oil, or combinations thereof.

7. A polyurea coating comprising:

and the component A: 12-14% by weight of a diisocyanate trimer; 10 to 30% by weight of a component A solvent,

and the component B: 8-14% by weight of polyaspartic acid ester; 1-3 wt% of an HDI trimeric urethane component; 0-55 wt% of a silica-based inorganic powder having a fineness of 200-2000 mesh, a nanoscale silica-based inorganic powder, or a combination thereof; 0-55 wt% of a pigment; 0-8% by weight of a plasticizer; 10-40 wt% of a component B solvent,

8. The polyurea coating of claim 7, wherein the pigment is selected from the group consisting of titanium dioxide-based pigments, carbon-based pigments, iron oxide-based pigments, cadmium selenide sulfide-based red-yellow pigments, lead chromate-based yellow pigments, and ultramarine-based pigments.

9. The polyurea coating of claim 8, wherein the pigment is selected from the group consisting of titanium dioxide, carbon black, iron oxide red, cadmium selenide sulfide, lead chromate, and ultramarine.

10. The polyurea coating of claim 7, wherein in formula 1, R is ethyl and X is a structure represented by formula 3 below:

optionally, in formula 2, R is a hexylene group.

11. The polyurea coating of claim 7, wherein the component b solvent is ethanol and methylal, and/or a mixture of one or more of ethyl acetate, dipropylene glycol dimethyl ether, and N-methylpyrrolidone in any ratio.

12. The polyurea coating of claim 7, wherein the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane; and/or

The inorganic powder based on silicon dioxide is selected from silica micropowder, glass beads, glass powder, white carbon black, quartz sand and a combination thereof; and/or