Environment-friendly polyurethane coating and preparation method thereof

Abstract

The invention discloses an environment-friendly polyurethane coating and a preparation method thereof, and the environment-friendly polyurethane coating is prepared from the following raw materials in parts by weight: 25-150 parts of waterborne polyurethane emulsion, 60-80 parts of an isocyanate curing agent, 0.3-0.6 part of a defoaming agent, 20-40 parts of deionized water, 18-29 parts of a flame retardant, 1-5 parts of a dispersing agent, 2-6 parts of chitosan modified coupling agent liquid, 0.01-0.3 part of an ultraviolet light absorber, 3-7 parts of modified wollastonite and 0.2-0.6 part of a surfactant. The environment-friendly polyurethane coating disclosed by the invention meets the environment-friendly requirement and has excellent wear resistance.

Description

Technical Field

[0001] The invention relates to the technical field of coating preparation, and in particular to an environmentally friendly polyurethane coating and a preparation method thereof. Background Art

[0002] Water-based paints include three types: water-soluble paints, water-dilutable paints, and water-dispersible paints (latex paints). Water-soluble paints use water-soluble resins as film-forming materials, represented by polyvinyl alcohol and its various modified products. In addition, there are water-soluble alkyd resins, water-soluble epoxy resins, and inorganic polymer water-based resins. Any paint that uses water as a solvent or a dispersion medium can be called a water-based paint. Based on the type of binder in the paint, water-based paints are divided into two categories: natural water-based paints made from natural substances or minerals (such as potassium silicate) and petrochemical water-based paints made from artificial synthetic resins (such as acrylic resins).

[0003] In order to extend the service life, people usually apply protective coatings on the surface of objects, especially cement products, galvanized materials, and steel structures such as bridges, storage tanks, pipelines, and ships. However, the volatile organic compounds in the coatings are harmful to humans and the environment. In addition, people's requirements for coating functions are getting higher and higher, such as wear resistance. Summary of the invention

[0004] The problem to be solved by the present invention is to provide an environmentally friendly polyurethane coating and a preparation method thereof, which meets environmental protection requirements and has excellent wear resistance.

[0005] The technical solution provided by the present invention for solving the above problems is: an environmentally friendly polyurethane coating, comprising the following raw materials in parts by weight, 25-150 parts of aqueous polyurethane emulsion, 60-80 parts of isocyanate curing agent, 0.3-0.6 parts of defoaming agent, 20-40 parts of deionized water, 18-29 parts of flame retardant, 1-5 parts of dispersant, 2-6 parts of chitosan modified coupling agent liquid, 0.01-0.3 parts of ultraviolet light absorber, 3-7 parts of modified wollastonite, and 0.2-0.6 parts of surfactant.

[0006] Preferably, the following raw materials are included in parts by weight: 60 parts of aqueous polyurethane emulsion, 65 parts of isocyanate curing agent, 0.6 parts of defoaming agent, 20 parts of deionized water, 20 parts of flame retardant, 1 part of dispersant, 3 parts of chitosan modified coupling agent liquid, 0.03 parts of ultraviolet light absorber, 3 parts of modified wollastonite, and 0.4 parts of surfactant.

[0007] Preferably, the following raw materials are included in parts by weight: 90 parts of aqueous polyurethane emulsion, 80 parts of isocyanate curing agent, 0.4 parts of defoaming agent, 28 parts of deionized water, 29 parts of flame retardant, 3 parts of dispersant, 6 parts of chitosan modified coupling agent liquid, 0.2 parts of ultraviolet light absorber, 5 parts of modified wollastonite, and 0.2 parts of surfactant.

[0008] Preferably, the following raw materials are included in parts by weight: 150 parts of aqueous polyurethane emulsion, 70 parts of isocyanate curing agent, 0.5 parts of defoaming agent, 40 parts of deionized water, 18 parts of flame retardant, 5 parts of dispersant, 2 parts of chitosan modified coupling agent liquid, 0.3 parts of ultraviolet light absorber, 7 parts of modified wollastonite, and 0.6 parts of surfactant.

[0009] The present invention also discloses a method for preparing an environmentally friendly polyurethane coating as described in any one of the above, the method comprising the following steps:

[0010] S1, preparing chitosan modified coupling agent liquid;

[0011] S2, preparing modified wollastonite;

[0012] S3, weighing the isocyanate curing agent, defoaming agent, flame retardant, deionized water, dispersant, ultraviolet light absorber and surfactant according to weight, putting them into a special stirring device for stirring;

[0013] S4, add water-based polyurethane emulsion, polysaccharide-modified coupling agent liquid and modified wollastonite to a special stirring device in sequence and stir evenly;

[0014] S5. After the stirring is completed, take it out, sterilize it and put it into cans to obtain the polyurethane coating.

[0015] Preferably, the method for preparing the chitosan modified coupling agent solution in S1 comprises the following steps:

[0016] S1.1, ethanol, coupling agent and water are mixed in a weight ratio of 2:1:5 to obtain a coupling agent liquid;

[0017] S1.2, adding acetic acid to the coupling agent solution, and then adding sodium alginate and stirring, wherein the weight ratio of sodium alginate to the coupling agent solution is 3 to 4:10;

[0018] S1.3. After the stirring is completed, chitosan is added, and the weight ratio of chitosan to coupling agent liquid is 2 to 3:10. The stirring is continued. After the stirring is completed, a chitosan-modified coupling agent liquid is obtained.

[0019] Preferably, the preparation method of the modified wollastonite in S2 comprises the following steps:

[0020] S2.1, add stearic acid to wollastonite powder, and put the mixture into a blender for stirring;

[0021] S2.2. After stirring, take out and cool to room temperature to obtain modified wollastonite.

[0022] Preferably, the stirring speed in S4 is 90-120 r / min, and the stirring time is 100-200 min.

[0023] Preferably, the dedicated stirring device in S1 includes a stirring barrel and a stirring component; the stirring component is used to stir the material in the stirring barrel.

[0024] Preferably, the stirring assembly includes a stirring motor, a stirring shaft, an auxiliary lifting stirring mechanism and a plurality of stirring paddles; the stirring motor is installed at the upper end of the stirring barrel, one end of the stirring shaft is connected to the motor belt transmission, and the other end extends into the stirring barrel, and the plurality of stirring paddles are evenly distributed on the stirring shaft, and the auxiliary lifting stirring mechanism rises and falls in the stirring barrel to stir the material in the stirring barrel up and down so that the material is stirred more evenly.

[0025] Compared with the prior art, the advantages of the present invention are: the VOC content of the polyurethane coating prepared by the present invention is ≤290g / L, which meets environmental protection requirements; and the polyurethane coating has excellent wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 It is a flowchart of the preparation process of the polyurethane coating of the present invention;

[0028] Figure 2 It is a flowchart of the preparation process of the chitosan modified coupling agent solution of the present invention;

[0029] Figure 3 It is a flowchart of the preparation process of the modified wollastonite of the present invention;

[0030] Figure 4 It is a structural schematic diagram of the special stirring device of the present invention;

[0031] Figure 5 is a cross-sectional view of the special stirring device of the present invention;

[0032] Figure 6 yes Figure 5 The enlarged schematic diagram of point A in the middle;

[0033] Figure 7 is a top view of the auxiliary lifting and stirring mechanism of the present invention;

[0034] Figure 8 It is a schematic diagram of the positioning axis of the present invention. Figure 1 ;

[0035] Fig. 9 It is a schematic diagram of the positioning axis of the present invention. Figure 2 .

[0036] The attached drawings are marked with: 1. stirring barrel, 2. stirring motor, 3. upper cover, 4. positioning shaft, 5. stirring frame, 6. stirring shaft, 7. stirring paddle, 8. stirring blade, 9. scraper blade 1, 10. scraper blade 2, 11. connecting head, 12. guide head, 13. movable hole, 14. spiral rising groove, 15. reset groove. DETAILED DESCRIPTION

[0037] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0038] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise specified and limited, the terms "assemble", "connect", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0042] It should also be understood that the terms used in this description of the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present invention. As used in the description of the embodiments of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms.

[0043] Example 1

[0044] The present embodiment discloses an environmentally friendly polyurethane coating, comprising the following raw materials in parts by weight: 25-150 parts of aqueous polyurethane emulsion, 60-80 parts of isocyanate curing agent, 0.3-0.6 parts of defoaming agent, 20-40 parts of deionized water, 18-29 parts of flame retardant, 1-5 parts of dispersant, 2-6 parts of chitosan modified coupling agent liquid, 0.01-0.3 parts of ultraviolet light absorber, 3-7 parts of modified wollastonite, and 0.2-0.6 parts of surfactant.

[0045] In the above scheme, after the modified wollastonite acts on the polyurethane coating, the affinity, compatibility and processing fluidity between the components can be improved. When the macromolecular chains of the polyurethane coating are subjected to stress, the addition of the modified wollastonite enhances the mutual binding force between the molecules, making it easier for the macromolecular chains to transfer the stress to other molecular chains through cross-linked particles, thereby reducing the friction stress in the local area and improving the wear resistance. At the same time, the addition of chitosan-modified coupling agent liquid can enhance the interfacial properties of the polyurethane coating, thereby enhancing the reaction contact effect between the products, and further enhancing the anti-corrosion and flame retardant properties of the product system.

[0046] Example 2

[0047] The present embodiment discloses an environmentally friendly polyurethane coating, comprising the following raw materials in parts by weight: 60 parts of aqueous polyurethane emulsion, 65 parts of isocyanate curing agent, 0.6 parts of defoaming agent, 20 parts of deionized water, 20 parts of flame retardant, 1 part of dispersant, 3 parts of chitosan modified coupling agent liquid, 0.03 parts of ultraviolet light absorber, 3 parts of modified wollastonite, and 0.4 parts of surfactant.

[0048] Example 3

[0049] The present embodiment discloses an environmentally friendly polyurethane coating, comprising the following raw materials in parts by weight: 90 parts of aqueous polyurethane emulsion, 80 parts of isocyanate curing agent, 0.4 parts of defoaming agent, 28 parts of deionized water, 29 parts of flame retardant, 3 parts of dispersant, 6 parts of chitosan modified coupling agent liquid, 0.2 parts of ultraviolet light absorber, 5 parts of modified wollastonite, and 0.2 parts of surfactant.

[0050] Example 4

[0051] The present embodiment discloses an environmentally friendly polyurethane coating, comprising the following raw materials in parts by weight: 150 parts of aqueous polyurethane emulsion, 70 parts of isocyanate curing agent, 0.5 parts of defoaming agent, 40 parts of deionized water, 18 parts of flame retardant, 5 parts of dispersant, 2 parts of chitosan modified coupling agent liquid, 0.3 parts of ultraviolet light absorber, 7 parts of modified wollastonite, and 0.6 parts of surfactant.

[0052] Example 5

[0053] This embodiment discloses a method for preparing an environmentally friendly polyurethane coating, which comprises the following steps:

[0054] S1, preparing chitosan modified coupling agent liquid;

[0055] S2, preparing modified wollastonite;

[0056] S3, weighing the isocyanate curing agent, defoaming agent, flame retardant, deionized water, dispersant, ultraviolet light absorber and surfactant according to weight, putting them into a special stirring device for stirring;

[0057] S4, add water-based polyurethane emulsion, polysaccharide-modified coupling agent liquid and modified wollastonite to a special stirring device in sequence and stir evenly at a stirring speed of 90 to 120 r / min for a stirring time of 100 to 200 min;

[0058] S5. After the stirring is completed, take it out, sterilize it and put it into cans to obtain the polyurethane coating.

[0059] Wherein, the preparation method of the chitosan modified coupling agent solution in S1 comprises the following steps:

[0060] S1.1, ethanol, coupling agent and water are mixed in a weight ratio of 2:1:5 to obtain a coupling agent liquid;

[0061] S1.2, adding acetic acid to the coupling agent solution, and then adding sodium alginate and stirring, wherein the weight ratio of sodium alginate to the coupling agent solution is 3 to 4:10;

[0062] S1.3. After the stirring is completed, chitosan is added, and the weight ratio of chitosan to coupling agent liquid is 2 to 3:10. The stirring is continued. After the stirring is completed, a chitosan-modified coupling agent liquid is obtained.

[0063] Wherein, the preparation method of the modified wollastonite in S2 comprises the following steps:

[0064] S2.1, add stearic acid to wollastonite powder, and put the mixture into a blender for stirring;

[0065] S2.2. After stirring, take out and cool to room temperature to obtain modified wollastonite.

[0066] Example 6

[0067] This embodiment discloses a special stirring device, which is applied in Embodiment 5. Specifically, the special stirring device includes a stirring barrel 1 and a stirring component; the stirring component is used to stir the material in the stirring barrel 1.

[0068] In this embodiment, specifically, the stirring assembly includes a stirring motor 2, a stirring shaft 6, an auxiliary lifting stirring mechanism and a plurality of stirring paddles 7; the stirring motor 2 is installed at the upper end of the stirring barrel 1, one end of the stirring shaft 6 is connected to the motor belt transmission, and the other end extends into the stirring barrel 1, and the plurality of stirring paddles 7 are evenly distributed on the stirring shaft 6, and the auxiliary lifting stirring mechanism is lifted up and down in the stirring barrel 1 to stir the material in the stirring barrel 1 up and down so that the material can be stirred more evenly.

[0069] The auxiliary lifting and stirring mechanism includes a positioning shaft 4, a stirring frame 5 and a connecting head 11. The positioning shaft 4 is arranged at the center position of the lower end surface of the upper cover 3 of the stirring barrel 1. The positioning shaft 4 is provided with a matching hole for the stirring shaft 6 to pass through. The connecting head 11 is provided with a movable hole 13 that matches the outer ring of the positioning shaft 4. A guide head 12 is arranged in the movable hole 13. A guide groove that matches the guide head 12 is arranged on the outer circumferential surface of the positioning shaft 4. The guide groove includes a spiral rising groove 14 and a reset groove 15. The spiral rising groove 14 is spirally arranged on the positioning shaft 4. One end of the reset groove 15 is connected to the bottom of the spiral rising groove 14, and the other end is connected to the top of the spiral rising groove 14. The stirring frame 5 is connected to the outer circumferential surface of the connecting head 11. The stirring frame 5 includes a frame body, a plurality of scrapers 9 and a plurality of stirring blades 8. The scraper blade 9 is vertically arranged on the frame body, and the stirring blade 8 is horizontally arranged on the frame body. A scraper blade 2 10 is arranged on the side of the stirring blade 8 close to the stirring barrel 1.

[0070] In the above scheme, after the stirring motor is turned on, the stirring shaft and the stirring paddle drive the materials in the stirring barrel to stir. Under the action of the flowing materials, the stirring frame rotates with the materials. During the rotation of the stirring frame, the connecting head is driven to rotate. During the rotation of the connecting head, the guide head on the connecting head moves upward along the spiral rising groove, thereby driving the stirring paddle to move upward. When the guide head reaches the top of the spiral rising groove, the guide head enters the reset groove from the spiral rising groove and moves downward until it reaches the bottom of the spiral rising groove. The guide head rotates up and down and reciprocates in this way, thereby driving the stirring frame to move up and down while rotating, and the scraper blade one on the stirring frame rotates and scrapes the inner wall of the stirring barrel, and the scraper blade two scrapes the inner wall of the stirring barrel up and down, thereby effectively scraping off the material adhering to the inner wall of the stirring barrel. At the same time, the stirring blade on the stirring frame rotates and reciprocates up and down driven by the stirring frame, thereby improving the stirring effect of the material in the stirring barrel.

[0071] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. All changes made within the scope of protection of the independent claims of the present invention are within the scope of protection of the present invention.

Claims

1. An environmentally friendly polyurethane coating, characterized in that: The invention comprises the following raw materials in parts by weight: 25-150 parts of waterborne polyurethane emulsion, 60-80 parts of isocyanate curing agent, 0.3-0.6 parts of defoaming agent, 20-40 parts of deionized water, 18-29 parts of flame retardant, 1-5 parts of dispersant, 2-6 parts of chitosan modified coupling agent liquid, 0.01-0.3 parts of ultraviolet light absorber, 3-7 parts of modified wollastonite and 0.2-0.6 parts of surfactant.

2. The environmentally friendly polyurethane coating according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 60 parts of waterborne polyurethane emulsion, 65 parts of isocyanate curing agent, 0.6 parts of defoaming agent, 20 parts of deionized water, 20 parts of flame retardant, 1 part of dispersant, 3 parts of chitosan modified coupling agent liquid, 0.03 parts of ultraviolet light absorber, 3 parts of modified wollastonite and 0.4 parts of surfactant.

3. The environmentally friendly polyurethane coating according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 90 parts of waterborne polyurethane emulsion, 80 parts of isocyanate curing agent, 0.4 parts of defoaming agent, 28 parts of deionized water, 29 parts of flame retardant, 3 parts of dispersant, 6 parts of chitosan modified coupling agent liquid, 0.2 parts of ultraviolet light absorber, 5 parts of modified wollastonite and 0.2 parts of surfactant.

4. The environmentally friendly polyurethane coating according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 150 parts of waterborne polyurethane emulsion, 70 parts of isocyanate curing agent, 0.5 parts of defoaming agent, 40 parts of deionized water, 18 parts of flame retardant, 5 parts of dispersant, 2 parts of chitosan modified coupling agent liquid, 0.3 parts of ultraviolet light absorber, 7 parts of modified wollastonite and 0.6 parts of surfactant.

5. A method for preparing an environmentally friendly polyurethane coating as claimed in any one of claims 1 to 4, characterized in that: The method comprises the following steps, S1, preparing chitosan modified coupling agent liquid; S2, preparing modified wollastonite; S3, weighing the isocyanate curing agent, defoaming agent, flame retardant, deionized water, dispersant, ultraviolet light absorber and surfactant according to weight, putting them into a special stirring device for stirring; S4, add water-based polyurethane emulsion, polysaccharide-modified coupling agent liquid and modified wollastonite to a special stirring device in sequence and stir evenly; S5. After the stirring is completed, take it out, sterilize it and put it into cans to obtain the polyurethane coating.

6. The environmentally friendly polyurethane coating according to claim 5, characterized in that: The method for preparing the chitosan modified coupling agent solution in S1 comprises the following steps: S1.1, ethanol, coupling agent and water are mixed in a weight ratio of 2:1:5 to obtain a coupling agent liquid; S1.2, adding acetic acid to the coupling agent solution, and then adding sodium alginate and stirring, wherein the weight ratio of sodium alginate to the coupling agent solution is 3 to 4:10; S1.

3. After the stirring is completed, chitosan is added, and the weight ratio of chitosan to coupling agent liquid is 2 to 3:

10. The stirring is continued. After the stirring is completed, a chitosan-modified coupling agent liquid is obtained.

7. The environmentally friendly polyurethane coating according to claim 5, characterized in that: The preparation method of the modified wollastonite in S2 comprises the following steps: S2.1, add stearic acid to wollastonite powder, and put the mixture into a blender for stirring; S2.

2. After stirring, take out and cool to room temperature to obtain modified wollastonite.

8. The method for preparing an environmentally friendly polyurethane coating according to claim 7, characterized in that: In the S4, the stirring speed is 90-120 r / min, and the stirring time is 100-200 min.

9. The method for preparing an environmentally friendly polyurethane coating according to claim 7, characterized in that: The dedicated stirring device in S1 includes a stirring barrel and a stirring assembly; the stirring assembly is used to stir the material in the stirring barrel.

10. The method for preparing an environmentally friendly polyurethane coating according to claim 9, characterized in that: The stirring assembly includes a stirring motor, a stirring shaft, an auxiliary lifting stirring mechanism and a plurality of stirring paddles; the stirring motor is installed at the upper end of the stirring barrel, one end of the stirring shaft is connected to the motor belt transmission, and the other end extends into the stirring barrel, and the plurality of stirring paddles are evenly distributed on the stirring shaft, and the auxiliary lifting stirring mechanism rises and falls in the stirring barrel to stir the material in the stirring barrel up and down so that the material is stirred more evenly.

Images