CN114989708B

CN114989708B - Odor-free polyurea coating and preparation method thereof

Info

Publication number: CN114989708B
Application number: CN202210199491.1A
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: CN114989708A

Abstract

The present invention provides an odor-free polyurea coating comprising a diisocyanate trimer, optionally acetone, polyaspartate, an HDI trimer-type urethane component, an inorganic powder, a plasticizer, a pigment, optionally methylal, and an odor-free solvent. The invention also provides a method for preparing the polyurea coating.

Description

Odor-free polyurea coating and preparation method thereof

Technical Field

The invention belongs to the field of polyurea coatings. In particular, the invention relates to an odor-free polyurea coating and a method for preparing the same.

Background

Polyurea coatings have been widely used in many fields such as the automotive industry, the marine industry, the construction industry, etc. because of the advantages of fast curing, high solid content, moisture resistance, excellent physicochemical properties, etc. However, with the continuous expansion of application scenes and the increasing severity of environmental regulations, the pungent odor of polyurea coatings during construction has also become one of the important factors affecting the application thereof.

These flavors originate from the harmful free isocyanate and liquid amine in the polyurea coating, and when spraying the polyurea, the constructor must wear gas masks, goggles, rubber gloves, wear protective clothing and shoes, etc., and should stand at the tuyere for working. The polyurea coating meets the environmental protection requirement only under the conditions that the coating is fully reacted, completely polymerized and forms macromolecular polyurea elastomer and does not contain free monomers.

Thus, there is a need for a polyurea coating that does not produce an unpleasant taste during application. In addition, it is also desirable that such polyurea coatings can be applied using conventional coating equipment and have a relatively high solids content.

In this regard, the invention provides a novel odor-free polyurea coating and a preparation method thereof, thereby solving some technical problems existing in the art.

Disclosure of Invention

In a first aspect of the present invention, there is provided an odor-free 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 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 HDI trimer type carbamate component is carbamate formed by HDI trimer and monohydroxy compound, which 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 the combination thereof,

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

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

in another embodiment, in formula 2, R is a hexylene group. In yet another embodiment, the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane.

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 inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon black, quartz sand, and combinations thereof. In another embodiment, the inorganic powder is present in an amount of at least 45% by weight. In one embodiment, the plasticizer is silicone, dipropylene glycol dibenzoate, liquid paraffin, or a combination thereof.

In one embodiment, the odor elimination solvent is selected from the group consisting of ethanol, odor elimination solvents in an exempt solvent list allowed by the U.S. ASTM D3960-98 standard, odor elimination solvents in a hazardous air contaminant "green solvent list" not in the third clean air regulations amendment, U.S. and European Union No HAP/NAP "and combinations thereof. In another embodiment, the odor-free solvent is ethanol. In yet another embodiment, the odor eliminating solvent is ethanol having a purity of 98% by weight or more.

In a second aspect of the present invention, there is provided an odor-free polyurea coating comprising or consisting of:

the HDI trimer type urethane component is a urethane formed from an HDI trimer and a monohydroxy compound 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 stearyl methylene triurea tricarbamate, 1, 4-butanediol methyl stearyl methylene triurea tricarbamate, silicone stearyl methylene triurea, and combinations thereof, wherein weight percent is based on the weight of the polyurea coating.

In one embodiment, the inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon black, quartz sand, and combinations thereof. In another embodiment, the inorganic powder is present in an amount of at least 45% by weight. In one embodiment, the plasticizer is silicone, dipropylene glycol dibenzoate, liquid paraffin, or a combination thereof. In one embodiment, the ethanol is ethanol having a purity of 98% by weight or greater.

In a third aspect of the present invention, there is provided a process for preparing the odor-free polyurea coating of the first aspect of the present invention, comprising: uniformly mixing diisocyanate trimer represented by the general formula 2 with acetone, thereby obtaining a component A; uniformly mixing an HDI trimer type carbamate component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, adding an odor-removing solvent and methylal, and uniformly mixing to obtain an B component; mixing the first component with the second component, thereby obtaining the polyurea coating.

In a fourth aspect of the present invention, there is provided a process for preparing the odor-free polyurea coating of the second aspect of the present invention, comprising: a diisocyanate trimer represented by the general formula 2, for example, a diisocyanate trimer represented by the general formula 2 in which R is a hexamethylene group is used as the a component; uniformly mixing an HDI trimer type urethane component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, and then adding ethanol and uniformly mixing, thereby obtaining a component B; mixing the first component with the second component, thereby obtaining the polyurea coating.

In a fifth aspect of the invention, there is provided the use of ethanol as a solvent and diluent in an odor-free polyurea coating.

In a sixth aspect of the invention there is provided the use of ethanol, methylal and acetone as solvents in an odor-free polyurea coating.

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 of a working electrode coated with four different coatings, where fig. 2 (a) is the corrosion of a working electrode coated with an epoxy mid-coat, fig. 2 (b) is the corrosion of a working electrode coated with an acrylic polyurethane, fig. 2 (c) is the corrosion of a working electrode coated with a polyester, and fig. 2 (d) is the corrosion of a working electrode 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.

Although polyurea coatings having a gel time greater than 1 hour are often referred to in the art as slow polyurea coatings, the polyurea coatings described herein are slow polyurea coatings, i.e., coatings having a gel time greater than 1 hour at ambient temperature (25.+ -. 0.2 ℃). In this context, the curing of polyurea coatings is achieved mainly by crosslinking reactions with chain extenders.

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: when in 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, then the paint flows out, a stopwatch is started for timing 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 for 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 modifying alkyl or alkylene _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 odor-free type I polyurea coating comprises or consists of:

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

in yet another embodiment, the polyaspartic acid ester may be present in an amount of 12 to 14 wt.%, for example 12 wt.%, 13 wt.%, or 14 wt.%.

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

in formula 2, R is C _3-10 A linear alkylene group.

In another embodiment, in formula 2, R is a hexamethylene, i.e., hexamethylene diisocyanate trimer. In yet another embodiment, the diisocyanate trimer may be present in an amount of 12 to 14 wt.%, for example 12 wt.%, 13 wt.%, or 14 wt.%.

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.

In one embodiment, the HDI trimeric urethane component is 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, stearyl methylene triurea tricarbamate silicone and combinations thereof. In another 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. In yet another embodiment, the HDI trimeric urethane component is present in an amount of 2 to 3 wt.%, for example 2 wt.%, 2.5 wt.%, or 3 wt.%.

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 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 yet another embodiment, the pigment is present in an amount of 9 to 40 wt%, for example 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%.

The odor-free polyurea coating of the present invention comprises a relatively fluid inorganic powder, which in one embodiment may be a silica-based inorganic powder having a fineness of 200 mesh or more to a nanometer level, such as a 500-800 mesh silica-based inorganic powder. In one embodiment, the inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon black, quartz sand, and combinations thereof. In another embodiment, the inorganic powder is present in an amount of 10 to 50 weight percent. In yet another embodiment, the inorganic powder is present in an amount of at least 45 wt%, such as at least 45.20 wt%.

The inventors of the present application found that an inorganic powder having a good fluidity such as silica can produce a good effect in this respect, however, it should be noted that the inorganic powder has a water content of less than 0.5%, otherwise it causes uneven dispersion, possibly causing small particle-like defects on the surface of the coating, and thus may affect the glossiness of the surface of the coating. For the polyurea coating of the invention, the above inorganic powders can be used such that the solids content in the polyurea coating exceeds 75% by weight, and may even exceed 90% by weight, for example, in the following formulations of the polyurea coating, the solids content is up to 90.77% by weight.

In one embodiment, the plasticizer is silicone, dipropylene glycol dibenzoate, liquid paraffin, or a combination thereof. In another embodiment, the plasticizer is dipropylene glycol dibenzoate, and in yet another embodiment, the plasticizer is present in an amount of 5-8 wt%, such as 5 wt%, 6 wt%, 7 wt%, or 8 wt%. 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 one embodiment, the odor eliminating solvent is selected from the group consisting of ethanol, odor eliminating solvents in the exempt solvent list permitted by the U.S. ASTM D3960-98 standard, odor eliminating solvents in the U.S. and European Union Non HAP/NAP "not in the third clean air regulations amendment, hazardous air pollutants" green solvents list, and combinations thereof. In another embodiment, the odor-free solvent is ethanol. In yet another embodiment, the odor eliminating solvent is ethanol having a purity of 98% by weight or more. In one embodiment, the ethanol is present in an amount of 3 to 4 wt.%. Of course, this range refers to the content when ethanol is used as a solvent, and if ethanol is used as a paint diluent, the amount added is not limited.

In one embodiment, the odor-free type II polyurea coating comprises or consists of:

the descriptions above for diisocyanate trimer, polyaspartate, HDI trimer type urethane component, inorganic powder, plasticizer, pigment are applicable to the odor-free type II polyurea coating and therefore are not repeated.

For example, in one embodiment, the polyaspartic acid ester may be present in an amount of 9 to 14 wt%, such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, or 14 wt%. In another embodiment, the diisocyanate trimer may be present in an amount of 9 to 14 wt.%, for example 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, or 14 wt.%. In yet another embodiment, the ethanol may be present in an amount of 8-45 wt%, such as 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%.

In the above-described odor-free type I and type II polyurea coatings, 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 polyurea development: 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.

Solvent(s)

As described above, isocyanate groups (-NCO) and liquid amines and the like in the polyurea coating material emit toxic and irritating odors, so that additional protection is required for constructors during construction, and the constructors still need to stand at the tuyere for operation. For the polyurea coatings of the present invention, ethanol can be used directly as a solvent and diluent, achieving unexpected beneficial effects in terms of odor removal, low viscosity, and long gel time.

Ethanol has a large number of applications in medicine, detergents, pesticides, etc., but is rarely used in paint. For example, in aqueous coatings, ethanol is typically not used, as ethanol is likely to adversely affect the properties (e.g., emulsification) of some aqueous coatings and also reacts with isocyanate, thereby reducing the coating strength. In oil-based paint, ethanol is also used only as an active solvent.

For polyurethane-based coatings, ethanol is also generally considered unsuitable as a solvent because ethanol contains hydroxyl groups which react with isocyanate to form urethane and the ethanol molecule is small, which reaction is rapid. Thus, there are many references in the art specifically describing the inability of ethanol to be a solvent and diluent for polyurethane-based coatings (e.g., paint solvent selection Xia Zheng, tu Weiping, yang Zhuoru, chen Huanqin, paint industry 2000,5).

However, the inventors of the present application found that ethanol, when used as a solvent of the second component of the polyurea coating and as a diluent for the polyurea coating, can prevent the polyurea coating from generating excessive pungent odor, and that the regulations of safety regulations on hazardous chemicals do not regulate low concentration ethanol, which also provides more convenience for the source of ethanol. In addition, among all chemical solvents, ethanol is a solvent having minimal harmful effects on humans, and can be rapidly decomposed in nature.

In the field of paint, the criteria for selecting a solvent are mainly that the solvent is required to match the dissolution capacity and volatility of the solvent with the film forming of the paint, to be as safe as possible in terms of flash point, toxicity, to be as inexpensive as possible, and to meet the following technical conditions:

1. dissolving or dispersing the resin in the coating, and adjusting the viscosity and rheological property of the resin to facilitate coating;

2. the storage stability of the paint is improved;

3. improving the appearance of the coating film, such as gloss, fullness, etc.;

4. the wettability of the paint to the substrate to be coated is increased, and the adhesive force is improved;

5. the paint has reasonable volatilization rate, and can endow the paint with optimal fluidity and leveling property;

6. the most stable and optimal balance of performances among various solvents is realized, and meanwhile, filling materials are added as much as possible, so that the cost is optimized and the construction viscosity is adjusted.

In addition, the diluent is also one of the solvents, and the main difference between the diluent and the solvent is that the solvent has higher requirements on the storage and use stability of the coating. The thinner has lower requirements in this aspect, so long as the thinner can be matched with the paint for dilution, has light color, does not influence the color of the paint, has low toxicity, does not cause health hazard to constructors as much as possible, and has relatively low cost.

In the polyurea coating of the present invention, the ethanol content is very low as the solvent of the second component, and the above effects can be achieved. In addition, the acetone content is also low or even absent, achieving the above effect as is the case with ethanol.

Ethanol is suitable for being used as a solvent and a diluent in the slow-speed polyurea coating, ensures various performances of the full-speed polyurea coating, remarkably prolongs the gel time and the coating operation time of the polyurea coating, and has no harmful effect on the environment and people during construction, i.e. the coating product forms a film and is environment-friendly and the product construction is environment-friendly. In addition, ethanol is matched with methylal and acetone to serve as a solvent, and the technical requirements of the slow polyurea coating with the gel time of more than 3 hours (for example, more than 3.5 hours) can be met under the conditions of high solid content and low viscosity. The slow polyurea coating containing the compound solvent ratio can not emit toxic and pungent odor in the application process, and is an odor-free polyurea coating.

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.

Method for producing polyurea coatings

The method for preparing the odor-free type I polyurea coating comprises the following steps: uniformly mixing diisocyanate trimer represented by the general formula 2 with acetone, thereby obtaining a component A; uniformly mixing an HDI trimer type carbamate component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, adding an odor-removing solvent and methylal, and uniformly mixing to obtain an B component; mixing the first component with the second component, thereby obtaining the polyurea coating.

For example, in one embodiment, a method of preparing an odor-free type I polyurea coating includes: the diisocyanate trimer represented by the general formula 2 was reacted with acetone in 3 to 5:1, thereby obtaining a component A; the HDI trimer-type urethane component, polyaspartic acid ester represented by the general formula 1 and plasticizer were mixed in a ratio of 1:5-6:2-3, mixing the obtained mixture with inorganic powder and pigment according to the weight ratio of 1:2-3: mixing evenly in a weight ratio of 0.4-0.6, and then mixing the obtained mixture with ethanol and methylal in a weight ratio of 26-30:1-1.3:1, and uniformly mixing the components in a weight ratio to obtain a component B; mixing the component A and the component B according to a proportion of 1:5-6, thereby obtaining the polyurea coating.

In one embodiment, a method of preparing an odor-free type II polyurea coating comprises: the diisocyanate trimer represented by the general formula 2 (preferably hexamethylene diisocyanate) is used as the a component; uniformly mixing an HDI trimer type urethane component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, and then adding ethanol and uniformly mixing, thereby obtaining a component B; mixing the first component with the second component, thereby obtaining the polyurea coating.

When the component B is prepared, the liquid component is fully and uniformly mixed, and finally the inorganic powder is added. 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 another embodiment, after the methylal is added and mixed, the amount of methylal loss is measured and the lost methylal is 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).

Use and application of polyurea coating

The odor-free polyurea coating provided herein can be applied without special polyurea coating equipment due to no pungent odor, long gel time and low viscosity in construction, and effectively avoids destructive stress of the polyurea coating due to rapid 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 odor-free 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 odor-free 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 odor-free 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 odor-free 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 pigment is R930 titanium pigment produced by Japanese stone original Co., ltd; 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 octadecyl methylene triurea tricarbamic acid 1, 4-butanediol methyl ether ester 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 1, 4-butanediol methyl ether according to a certain equivalent ratio, and the mixture is stirred uniformly and kept stand for seven days to obtain the octadecyl methylene triurea tricarbamic acid 1, 4-butanediol methyl ether ester

Example 1

At room temperature, 137 parts of HDI trimer HT-100 and 35 parts of acetone are mixed together, and the mixture is fully and uniformly stirred by a dispersing stirrer (the mixture system 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 manner.

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

Comparative example 1

Polyurea coatings were prepared in the same manner as in example 1, except that xylene was used instead of acetone and ethyl acetate was used instead of methylal. The formulation of the polyurea coating of comparative example 1 is shown in table 2 below.

Table 2: formulation of polyurea coating of comparative example 1

The paint can then appear in three cases:

1. the smell is great, wherein the xylene has adverse effect on people and environment,

2. the surface drying and the actual drying time of the paint are prolonged. The open time was prolonged by about 20 minutes and the real time was prolonged by about 60 minutes as compared with example 1. In addition, xylene odor was not yet clear for about 7 days.

3. The gel time of the paint is shortened, and the painting construction time is often less than 1 hour.

Example 2

137 parts of HDI trimer HT-100 are used as the component A of the polyurea coating at room temperature, and the polyurea coating is stored in a sealed manner.

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, 650 parts of 800-mesh quartz sand and 150 parts of R930 titanium pigment are added, a three-roller mill is used for fully and uniformly grinding, 1037 parts of color paste of the polyurea coating is prepared, and then 110 parts of ethanol dispersing stirrer is added for fully and uniformly stirring, 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 = 137:1147, pouring the component B into the component A for mixing, and uniformly stirring to obtain the coating. The formulation of the polyurea coating of example 2 is shown in table 3 below.

Table 3: formulation of polyurea coating of example 2

Experimental example 1

The following table shows the test results for the polyurea coatings obtained in examples 1 and 2.

Table 4: 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 water resistance and corrosion resistance of polyurea No. 04 are 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 5 below.

Table 5: salt spray test results of polyurea coatings of the invention

Test time (hours)	Test results
		120	No expansion and no foaming at scribing position
240	Scribing lineSingle side 1mm expansion without foaming phenomenon
		336	1mm of scribing single side is expanded, and no foaming phenomenon exists
456	1mm of scribing single side is expanded, and no foaming phenomenon exists
		576	1mm of scribing single side is expanded, and no foaming phenomenon exists
672	1mm of scribing single side is expanded, and no foaming phenomenon exists
		792	1mm of scribing single side is expanded, and no foaming phenomenon exists
1008	2mm of scribing single side is expanded, and no foaming phenomenon exists
		1296	2mm of scribing single side is expanded, and no foaming phenomenon exists
1448	2mm of scribing single side is expanded, and no foaming phenomenon exists
		1752	2mm of scribing single side is expanded, and no foaming phenomenon exists
2000	2mm of scribing single side is expanded, and no foaming phenomenon exists

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, and thus can sufficiently wet the base surface, and no destructive stress is present at the interface and in the interior of the coating.

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. An odor-free polyurea coating comprising: 12-14% by weight of a diisocyanate trimer; 3-4 wt% acetone; 12-14% by weight of polyaspartic acid ester; 2-3% by weight of an HDI trimeric urethane component; 10-50 wt% of an inorganic powder; 5-8 wt% of a plasticizer; 9-40 wt% of a pigment; 2-3% by weight of methylal; 3-4% by weight of an odor-free 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,

octadecyl methylene triurea tricarbamic acid silicone ester

Wherein weight percent is based on the weight of the polyurea coating, and wherein the solids content of the polyurea coating exceeds 75 weight percent.

2. 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;

optionally, the HDI trimeric urethane component is octadecyl methylene triurea tricarbamic siloxane.

3. The polyurea coating according to claim 1 or 2, wherein 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, and ultramarine-based pigments;

optionally, the inorganic powder is selected from the group consisting of silica fume, glass beads, glass frit, white carbon, quartz sand, and combinations thereof, and the inorganic powder is present in an amount of at least 45 wt%;

optionally, the plasticizer is silicone, dipropylene glycol dibenzoate, liquid paraffin, or a combination thereof.

4. The polyurea coating of claim 1 or 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.

5. The polyurea coating of claim 1 or 2, wherein the odor-free solvent is ethanol.

6. The polyurea coating of claim 1 or 2, wherein the odor eliminating solvent is ethanol having a purity of 98% by weight or more.

7. A method of preparing the odor-free polyurea coating of any one of claims 1 to 6, comprising:

uniformly mixing diisocyanate trimer represented by the general formula 2 with acetone, thereby obtaining a component A;

uniformly mixing an HDI trimer type carbamate component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, adding an odor-removing solvent and methylal, and uniformly mixing to obtain an B component;

mixing the first component with the second component, thereby obtaining the polyurea coating.

8. An odor-free polyurea coating comprising: 9-14% by weight of a diisocyanate trimer; 9-14% by weight of polyaspartic acid ester; 2-3% by weight of an HDI trimeric urethane component; 10-50 wt% of an inorganic powder; 5-8 wt% of a plasticizer; 9-40 wt% of a pigment; 8-45% by weight of ethanol,

octadecyl methylene triurea tricarbamic acid silicone ester

9. The polyurea coating of claim 8, 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;

10. The polyurea coating according to claim 8 or 9, wherein 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;

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

12. The polyurea coating of claim 8 or 9, wherein the ethanol is ethanol having a purity of 98 wt.% or more.

13. A method of preparing the odor-free polyurea coating of any one of claims 8 to 12, comprising:

the diisocyanate trimer represented by the general formula 2 is used as the a component;

uniformly mixing an HDI trimer type urethane component, polyaspartic acid ester represented by a general formula 1 and a plasticizer, mixing the obtained mixture with inorganic powder and pigment, and then adding ethanol and uniformly mixing, thereby obtaining a component B;