WO2023240946A1 - Water-based prefabrication primer, coating, and product with coating - Google Patents

Abstract

Provided in the present disclosure are a water-based prefabrication primer, a coating, and a product with the coating, which belong to the technical field of coatings. The water-based prefabrication primer is used in cooperation with a polyurea finish paint. The water-based prefabrication primer comprises a first component, which comprises a water-based epoxy modified polyurethane resin, wherein the water-based epoxy modified polyurethane resin contains an epoxy group and a polyurethane group. In the water-based prefabrication primer provided in the present disclosure, the water-based epoxy modified polyurethane resin is used as a base material, such that the adhesive force of an existing water-based prefabrication primer and a polyurea finish paint coating can be effectively improved; and when used in combination with a polyurea finish paint, the water-based prefabrication primer has good compatibility with the polyurea finish paint, and can be used in a shot blasting pretreatment process for a steel material before the steel material is coated with the polyurea finish paint.

Description

A kind of water-based pre-coated primer, coating and coated products

Cross-references to related applications

This disclosure claims priority from the Chinese patent application filed on June 17, 2022 with application number 202210691910.3 and titled "A water-based pre-coated primer, coating and products with coating", the entire content of which is incorporated by reference Merged here.

Technical field

The present disclosure relates to the technical field of coatings, and in particular to a water-based precoat primer, a coating and products with the coating.

Background technique

Polyurea topcoat coating is a coating made by spraying polyurea elastomer material with excellent wear resistance and impact resistance. It has good application prospects on railway vehicles. When applying, the common practice is to first perform shot blasting and rust removal during the blanking stage of the steel, and spray a layer of water-based pre-coat primer to provide short-term protection for the steel surface.

The conventional pre-coating primers currently used are mainly water-based epoxy ester pre-coating primers, water-based inorganic zinc-rich pre-coating primers, etc. However, in the existing technology, the adhesion between water-based pre-coating primers and polyurea topcoat coatings Difference.

public content

Some embodiments of the present disclosure provide a water-based pre-coat primer, a coating, and a coated product to solve the problem of poor adhesion between the existing water-based pre-coat primer and the polyurea topcoat coating.

In a first aspect of the present disclosure, a water-based pre-coat primer is provided. The water-based pre-coat primer is used in conjunction with a polyurea topcoat and includes: a first component, the first component includes a water-based epoxy Modified polyurethane resin, the water-based epoxy modified polyurethane resin contains epoxy groups and polyurethane groups.

In a second aspect of the present disclosure, a coating is provided, including: a polyurea topcoat layer, and a primer layer, the primer layer including the water-based precoat primer described in the first aspect, the polyurea The topcoat layer is coated on the surface of the primer layer away from the base material.

In a third aspect of the present disclosure, an article with a coating is provided, the article includes a substrate, and a coating adhered to at least a portion of the surface of the substrate, and the coating is the coating of the second aspect.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments These are some embodiments of the present disclosure, but not all embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present disclosure.

Various embodiments of the present disclosure may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity and should not be understood as a hard limit to the scope of the present disclosure; therefore, the range description should be considered All possible subranges have been specifically disclosed as well as the single numerical values within such ranges. For example, a description of a range from 1 to 6 should be considered to have specifically disclosed subranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and A single number within the stated range, such as 1, 2, 3, 4, 5, and 6, applies regardless of the range. Additionally, whenever a numerical range is indicated in this disclosure, it is intended to include any cited number (fractional or integer) within the indicated range. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present disclosure can be purchased in the market or prepared by existing methods.

In this disclosure, unless otherwise specified, the directional words used such as "upper" and "lower" refer specifically to the direction of the drawing in the drawings. In addition, in the description of the present disclosure, the terms "including", "including" and the like mean "including but not limited to". In this disclosure, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation and do not necessarily require or imply that such entities or operations are mutually exclusive. any such actual relationship or sequence exists between them. In this disclosure, "and/or" describes the association of associated objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone. Condition. Where A and B can be singular or plural. In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions thereof refers to any combination of these items, including any combination of a single item (items) or a plurality of items (items). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can mean: a, b, c, a-b ( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

In a first aspect, the present disclosure provides a water-based pre-coat primer, which is used in conjunction with a polyurea topcoat and includes: a first component, the first component includes water-based epoxy modification Polyurethane resin, the water-based epoxy modified polyurethane resin contains epoxy groups and polyurethane groups.

The water-based precoat primer of the present disclosure includes a water-based epoxy modified polyurethane resin, which uses the water-based epoxy modified polyurethane resin as a base material. The water-based epoxy modified polyurethane resin contains epoxy groups and polyurethane groups: on the one hand , the epoxy group has good wettability and permeability and strong adhesion to substrates such as steel; the polyurethane group contains an isocyanate prepolymer with a similar structure to the polyurea in the polyurea topcoat coating, and is similar to polyurea. The polymer molecules in the structure have good matching, good compatibility and high bonding strength, which can produce anchoring and interlocking effects with the polyurea topcoat coating to enhance the adhesion with the polyurea topcoat coating. That is, the water-based pre-coating primer provided by the embodiment of the present disclosure uses water-based epoxy modified polyurethane resin as the base material, and can effectively improve the adhesion between the existing water-based pre-coating primer and the polyurea topcoat coating. Therefore, the water-based precoat primer provided by the embodiments of the present disclosure has good usability with the polyurea topcoat, and can be applied to the steel shot blasting pretreatment process before the polyurea topcoat is applied to the steel. .

In some embodiments, the water-based epoxy modified polyurethane resin is obtained through a first chemical reaction. In parts by weight, the reaction raw materials for the first chemical reaction include: 15 to 65 parts of polyether polyol, 10 to 75 parts parts isocyanate and 1 to 10 parts epoxy resin.

The types of the above-mentioned polyether polyol, isocyanate and epoxy resin are not particularly limited, as long as the obtained product water-based epoxy modified polyurethane resin contains epoxy groups and polyurethane groups. When the weight parts ratio of polyether polyol, isocyanate and epoxy resin meets the above range, that is: (15～65): (10～75): (1～10), the water-based epoxy modified polyurethane resin The ratio of epoxy groups and polyurethane groups is more appropriate, which can further effectively improve the adhesion between the existing water-based precoat primer and the polyurea topcoat. Specifically, the weight parts ratio of the polyether polyol, the isocyanate and the epoxy resin can be 15:20:2, 20:30:3, 45:50:5, 60:70:8, etc. The polyether polyols include but are not limited to polyether polyol N204, polyether polyol N210, polyether polyol N220, polyether polyol N240, polyether polyol N280, polyether polyol N303, polyether polyol N303F, polyether polyol N305, polyether polyol N306, polyether polyol N307, polyether polyol N330, other appropriate polyether polyols, or any mixture of the above compounds; the isocyanate should be understood as isocyanate The general name of various esters, including monoisocyanate, diisocyanate and polyisocyanate, etc., specifically toluene diisocyanate TDI-80, isocyanate MDI-50, other appropriate isocyanates, or any mixture of the above compounds; the epoxy resin Including but not limited to epoxy resin E44, epoxy resin E51 and other appropriate epoxy resins, solutions of the above-mentioned epoxy resins, or any mixture of the above-mentioned compounds.

In some embodiments, the first component further includes: filler.

Fillers can be appropriately added according to the water-based pre-coating primer disclosed in the prior art and actual needs, such as adding silica micropowder and iron oxide red to improve the anti-corrosion performance and filling properties of the water-based pre-coating primer.

In some embodiments, the first component further includes: non-metal conductive material.

The function of the non-metallic conductive substance is to improve the conductivity of the water-based pre-coated primer after the film is formed, which is beneficial to the subsequent welding and processing of steel, and effectively improves the weldability of the existing water-based pre-coated primer; specifically, it can be graphene, Carbon nanotubes and other non-metal conductive substances.

In some embodiments, the first component has properties such that the fineness is ≤30 μm, and/or the viscosity is 2-10 Pa·S.

The water-based precoat primer also includes: a second component including a metal conductive substance.

The second component is selected from metal conductive substances. Its function is to cooperate with the non-metal conductive substances in the first component to further improve the conductivity of the water-based precoat primer after it is formed, so that it can be used without removal. Direct steel welding can be adapted to various manual welding and automatic welding processes without affecting the mechanical properties and formation of the weld, and no pores are generated at the weld position, effectively avoiding the problem of poor weldability of existing water-based pre-coated primers. .

In some embodiments, the metal conductive material is zinc powder.

The functions of zinc powder are as follows: on the one hand, it can effectively solve the problem of poor weldability of existing water-based pre-coated primers; on the other hand, zinc powder plays an anti-corrosion role. Under the action of the sacrificial anode, zinc has a negative impact on the coating. It acts as a sealing layer to strengthen the protection of the steel substrate and improve the corrosion resistance of the water-based pre-coated primer. The zinc powder can be zinc powder larger than 800 mesh.

In some embodiments, the mass ratio of the first component to the second component is (5-10):(2-5).

The effect of controlling the mass ratio of the first component and the second component to (5~10): (2~5) is that the paint film has good adhesion, anti-corrosion performance and weldability, and is also compatible with the polymer. The urea coating has good compatibility. If the ratio is too large, the adverse effect is poor weldability. If the ratio is too small, the adverse effect is poor adhesion of the paint film, poor anti-corrosion performance, and poor compatibility with the polyurea coating. The mass ratio of the first component to the second component can specifically be 5:2, 7:2, 7:3, 8:3, 10:3, etc., preferably 7:3.

It should be noted that: (1) the reaction process of the first chemical reaction can appropriately add neutralizers and catalysts according to the conventional synthesis method of water-based epoxy modified polyurethane resin in the prior art and actual needs. The agent is not particularly limited; the neutralizing agent is only used to neutralize the obtained product water-based epoxy modified polyurethane resin into a salt, which is beneficial to subsequent storage; the catalyst is used to initiate the reaction and can be selected from the group consisting of dilauric acid and dilaurate. Butyltin. The amount of neutralizing agent and catalyst can be appropriately selected according to the amount of reaction raw materials, which can promote the reaction of the polyether polyol, the isocyanate and the epoxy resin to generate a water-based epoxy modified polyurethane resin; if The amount of polyether polyol used as the reaction raw material is used as the basis. The amount of catalyst can be selected from 0.005 to 0.1wt% of the amount of polyether polyol, such as 0.08wt%, 0.01wt%, 0.011wt%, 0.05wt%, 0.08wt%. etc.; the amount of neutralizer can be selected from 0.005 to 0.1wt% of the polyether polyol, such as 0.08wt%, 0.01wt%, 0.011wt%, 0.05wt%, 0.08wt%, etc.; in addition, Chain extenders and end-capping agents can also be added to the reaction conditions of the first chemical reaction to further modify the water-based epoxy modified polyurethane resin. There are no special restrictions on the types of chain extenders and end-capping agents used. It is only necessary that the obtained product water-based epoxy modified polyurethane resin still retains epoxy groups and polyurethane groups; the reaction temperature and reaction time can also be based on the conventional synthesis method of water-based epoxy modified polyurethane resin in the prior art. Make appropriate selections on the disclosure content, for example, select the reaction temperature as 75-90°C, specifically 75°C, 78°C, 80°C, 81°C, 82°C, 85°C, 88°C, 90°C, etc.; the reaction time is 2-5h , specifically it can be 2h, 2.5h, 3h, 3.5h, 4h, 5h, etc.

(2) The first component can be appropriately added with additives and solvents and other fillers other than non-metallic conductive substances according to the water-based pre-coating primer disclosed in the prior art and actual needs to facilitate water-based epoxy modification The polyurethane resin base material can be evenly dispersed in the solvent, improving the convenience and operability of the water-based precoat primer when sprayed. Preferably, the auxiliaries include dispersants, defoaming agents and rheology auxiliaries, and the other fillers other than non-metallic conductive substances also include silica powder and iron oxide red.

In a second aspect, the present disclosure provides a coating, including: a polyurea topcoat layer, and a primer layer. The primer layer includes the above-mentioned water-based precoat primer. The polyurea topcoat layer is coated on The surface of the primer layer away from the base material.

The functions of this coating are as follows: on the one hand, the primer layer including the above-mentioned water-based pre-coat primer has excellent adhesion and anti-corrosion properties with base materials such as steel; on the other hand, the primer layer and the polyurea topcoat layer It has excellent adhesion and compatibility. Therefore, when the above-mentioned coating is applied to a base material such as steel, it not only has the excellent wear resistance, impact resistance and other properties brought by the polyurea topcoat layer, but also has excellent adhesion as a whole coating system. Specifically, it can reach more than 8MPa. The material used in the coating is the above-mentioned water-based pre-coating primer. Since the coating includes part or all of the technical solutions of the above-mentioned embodiments of the water-based pre-coating primer, it at least has the above-mentioned embodiments of the water-based pre-coating primer. All the beneficial effects brought by the technical solutions will not be repeated here.

In a third aspect, the present disclosure provides an article with a coating, the article includes a substrate, and a coating adhered to at least part of the surface of the substrate, and the coating is the coating according to the second aspect.

When the water-based pre-coated primer provided by the present disclosure is used together with the polyurea topcoat as an anti-corrosion coating on steel substrates and ceramic substrates, the existing process flow can be simplified, production efficiency can be improved, and production can be reduced. cost. Specifically, for example, in the coating process of polyurea topcoat coating on railway vehicles, compared with the conventional process method of polyurea topcoat coating on railway vehicles, there is no need to "clean up" after the car body is assembled and welded. Remove the precoat primer" and "spray again a layer of primer coating matching the polyurea topcoat coating", that is: steel shot blasting pretreatment → spraying the water-based precoat primer provided by the disclosed embodiment → car The body assembly is welded and formed → the surface of the car body is degreased and dusted → sprayed with polyurea topcoat. The process is simplified, the polyurea coating coating efficiency of railway freight cars is improved, and the cost is reduced. The surface of the product is coated with the above-mentioned coating. Since the product includes some or all of the technical solutions related to the embodiments of the coating, it at least has all the beneficial effects brought by the technical solutions related to the embodiments of the coating. I won’t go into details here.

The present disclosure will be further described below with reference to specific embodiments. It should be understood that these examples are only used to illustrate the present disclosure and are not intended to limit the scope of the present disclosure. Experimental methods without specifying specific conditions in the following examples are usually measured in accordance with national standards. If there is no corresponding national standard, general international standards, conventional conditions, or conditions recommended by the manufacturer shall be followed.

Example 1

Preparation of water-based pre-coating primer includes: Preparation of water-based epoxy modified polyurethane resin: In terms of parts by mass, add the dried polyether polyol N220 (45 parts) into a flask and put it into an electronic constant temperature water bath to maintain Keep the temperature at 80°C, turn on nitrogen for protection; then, after the temperature of the polyether polyol reaches 80°C, drop isocyanate MDI-50 (50 parts) into the flask, and after a period of reaction, add dissolved in N-methylpyrrolidone ( 2 parts) of epoxy resin E44 (5 parts), stir at a constant speed; then add dibutyltin dilaurate (0.5 parts), raise the temperature to 85°C, and stir at a constant speed for 3 hours; after the reaction is completed, cool to room temperature, add neutralizer Add triethylamine (1 part), stir for 30 minutes at 1000-1200r/min, shear and emulsify, and disperse in an ethylenediamine aqueous solution to obtain a water-based epoxy modified polyurethane resin.

Preparation of the first component: In terms of parts by mass, combine the water-based epoxy modified polyurethane resin (20 parts), deionized water (15 parts), dispersant (1 part), and defoaming agent (0.2 parts) prepared above. , non-metallic conductive substances (0.2 parts), silica powder (5 parts) and iron oxide red (10 parts) are put into the dispersion tank in sequence, and the materials are evenly dispersed and then ground to a fineness of ≤30 μm; then add the rheological additives (0.2 parts) is added to the medium-ground material, stir evenly and filter to remove impurities, adjust the viscosity of the filtered material to 2-10Pa·S, filter again to remove impurities, and discharge the material to obtain the first group of components; wherein, The dispersant is a polymeric non-ionic water-based dispersant, such as ADDI TTOL VXW 6208/60; the defoamer is a silicone water-based defoamer, such as silicone defoamer F-202; the rheology additive is associative polyurethane Thickening agent, such as RHEOLATE299 water-based rheology additive; non-metallic conductive material is graphene powder. Preparation of the second component: The second component is a 1000 mesh zinc powder (100 parts) filling product, purchased directly from Hunan Xinweiling Metal New Material Technology Co., Ltd.

The mass ratio of the first component to the second component in the water-based precoat primer is 5:2.

When the water-based precoat primer provided in this example is used, it can be applied to steel and other base materials by methods such as airless spraying, brushing, roller coating, etc., and it will be cured to form a film at a temperature of 5 to 35°C. The final dry film thickness is controlled within 20μm. In fact, the drying time is ≤5 minutes, which can meet the production rhythm of the shot blasting pretreatment line; it is green and environmentally friendly, and its VOC content is less than 100g/L.

Example 2 to Example 8

The preparation method of the water-based precoat primer of Examples 2 to 8 is the same as that of Example 1, and the only difference is: 1) the polyether in the water-based epoxy modified polyurethane resin used in Examples 2 to 4 The mass ratios of the polyol m1, the isocyanate m2 and the epoxy resin m3 are respectively 15:20:2 (15 parts by mass: 20 parts by mass: 2 parts by mass), 20:30:3 (20 parts by mass: 30 parts by mass: 3 parts by mass) and 60:70:8 (60 parts by mass: 70 parts by mass: 8 parts by mass); the mass ratio of the first component to the second component described in Example 3 is 7 :2; 2) The mass ratio of the water-based epoxy modified polyurethane resin, deionized water and non-metallic conductive material in the first component used in Examples 5 to 7 is respectively 30:20:20 (30 mass parts: 20 parts by mass: 20 parts by mass), 40:22:48 (40 parts by mass: 22 parts by mass: 48 parts by mass) and 60:25:60 (60 parts by mass: 25 parts by mass: 60 parts by mass); implementation The mass ratio of the first component to the second component in Example 6 is 7:3; the mass ratio of the first component to the second component in Example 7 is 8:3; 3 ) The mass ratio of the first component to the second component in Example 8 is 10:3.

Comparative example 1

This example provides a water-based epoxy pre-coated primer. The only difference from Example 1 is that the water-based epoxy modified polyurethane resin (20 parts) used is adjusted to a mass ratio of 2:1 Commercially available water-based epoxy phosphate resin and commercially available water-based acrylic modified epoxy resin; the remaining steps and parameters are the same.

The water-based pre-coating primer prepared in Examples 1-9 is applied in the process of spraying polyurea coating after shot blasting pretreatment of steel for railway vehicles, including: shot blasting pretreatment of steel for railway vehicles; The surface of the steel material for railway vehicles is sprayed with the water-based pre-coating primer prepared in Examples 1-9, and the dry film thickness after curing is controlled within 20 μm; the steel material for railway vehicles after being sprayed with the water-based pre-coating primer is processed into a car body Assembly welding and forming; remove oil and dust from the surface of the car body, and then spray polyurea topcoat (the specific polyurea coating model is Lumeng brand-SPUA906);

The overall performance of the resulting coating was tested. The adhesion test was based on the GB/T 5210 medium pull-off method, the neutral salt spray resistance test was based on GB/T1771, and the abrasion resistance test was based on GB/T 1768-2006. The specific data are shown in Table 1.

Table 1 Overall performance test results of coating

Test object	Adhesion/MPa	Resistant to neutral salt spray/120h	Wear resistance/700g, 500r
Example 1	12.5	Qualified; no blistering or rusting	7.2mg
Example 2	12.7	Qualified; no blistering or rusting	7.8mg
Example 3	12.0	Qualified; no blistering or rusting	7.5mg
Example 4	11.5	Qualified; no blistering or rusting	8.6mg
Example 5	8.9	Qualified; no blistering or rusting	10.1mg
Example 6	10.2	Qualified; no blistering or rusting	9.6mg
Example 7	9.5	Qualified; no blistering or rusting	12.4mg
Example 8	9.0	Qualified; no blistering or rusting	11.4mg
Comparative example 1	5.7	Qualified; no blistering or rusting	17.8 mg

It can be seen from Table 1 that the water-based pre-coating primer and the polyurea topcoat in the present disclosure have good compatibility or adaptability; at the same time, the water-based pre-coating primer is used for steel shot blasting pretreatment and the polyurea topcoat is applied , the adhesion of the entire coating system is not less than 8MPa, and the overall performance such as wear resistance is good. At the same time, the water-based pre-coated primer meets the requirements of fast drying speed and good weldability of the pre-coated primer: in terms of drying speed, the drying time is ≤5 minutes, which can meet the production rhythm of the shot blasting pretreatment line. After the steel comes off the line It can be stacked directly; in terms of weldability, the dry film thickness is controlled within 20 μm, which can be adapted to various manual welding and automatic welding processes without affecting the mechanical properties and formation of the weld, and no pores are generated at the weld position. Green and environmentally friendly: The VOC content in the paint is not greater than 100g/L.

The above descriptions are only specific embodiments of the present disclosure to enable those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined in this disclosure may be practiced in other embodiments without departing from the spirit or scope of the disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with its claimed principles and novel features.

Claims (10)

1. A water-based pre-coated primer used in conjunction with a polyurea topcoat, including:

   The first component includes a water-based epoxy modified polyurethane resin, which contains an epoxy group and a polyurethane group.
2. The water-based precoat primer according to claim 1, wherein the water-based epoxy modified polyurethane resin is obtained through a first chemical reaction, and in parts by weight, the reaction raw materials of the first chemical reaction include: 15 to 65 parts of polyether polyol, 10 to 75 parts of isocyanate and 1 to 10 parts of epoxy resin.
3. The water-based precoat primer of claim 1, wherein the first component further includes: filler.
4. The water-based precoat primer of claim 3, wherein the filler includes: non-metallic conductive substances.
5. The water-based precoat primer according to claim 1, wherein the physical properties of the first component satisfy: fineness is ≤30 μm, and/or viscosity is 2-10 Pa·S.
6. The water-based precoat primer according to any one of claims 1 to 5, further comprising:

   The second component includes metallic conductive substances.
7. The water-based precoat primer according to claim 6, wherein the metal conductive substance is zinc powder.
8. The water-based precoat primer according to claim 6, wherein the mass ratio of the first component to the second component is (5-10): (2-5).
9. A coating consisting of:

   Polyurea topcoat layer, and

   The primer layer includes the water-based precoat primer according to any one of claims 1 to 8, and the polyurea topcoat layer is coated on the surface of the primer layer away from the base material.
10. An article with a coating, the article contains a substrate, and a coating adhered to at least part of the surface of the substrate, and the coating is the coating according to claim 9.