Method for in-mold coating of hydrophobic polyurethane paint film on surface of non-polar base material

Abstract

The invention discloses a method for in-mold coating of a hydrophobic polyurethane paint film on the surface of a non-polar base material. The method comprises the following steps: curing a polyurethane paint A and a polyurethane paint B on the surface of a non-polar base material formed in a painting forming mold to form a film; the polyurethane paint vehicle A comprises a catalyst, polyol and a polyphenol compound; the polyurethane paint vehicle B comprises a component B1 and a component B2; the component B1 is selected from one or more of metal salt, functional organic silicon, a silane coupling agent, long-chain alcohol with 12-18 alkyl groups, long-chain amine with 12-18 alkyl groups, nanoparticles and a flame retardant; and the component B2 is polyisocyanate. According to the method, equipment and procedures are not additionally added in the in-mold painting integrated forming process, and wetting, spreading, rapid curing and firm adhesion of the polyurethane paint film on the surface of the non-polar base material are achieved.

Description

Technical Field

[0001] This invention relates to the field of in-mold coating integrated molding technology, specifically to a method for in-mold coating a hydrophobic polyurethane coating film onto the surface of a non-polar substrate. Background Technology

[0002] In-mold coating (IMC) is a technology that involves injection molding in one mold, followed by coating using reaction injection molding in another mold. It is an integrated molding process that combines thermoplastic injection molding and reactive in-mold coating. It has advantages such as short process, fewer steps, small equipment footprint, high degree of automation, no use of organic solvents, energy saving and environmental protection. It is of great significance for lightweight, green and efficient molding manufacturing of automobiles, transportation equipment and other products.

[0003] Polyurethane (PU) is a polymer formed by the reaction of polyisocyanates with polyethers, polyesters, or polycarbonate polyols. It possesses excellent scratch resistance, weather resistance, and chemical resistance, and its composition, structure, and properties can be controlled as needed. It is commonly used as a coating film in current IMC processes. The PU molecular chain contains polar groups such as urethane (-NHCOO-) and ester (-COO-), which allow it to spread and wet easily on polar substrates (such as PA, PC, ABS, etc.), forming strong adhesion through effective interactions such as covalent bonds, hydrogen bonds, and van der Waals forces.

[0004] However, for non-polar substrates, such as thermoplastic materials like polyethylene (PE) and polypropylene (PP) widely used in the automotive industry, the low surface energy and lack of polar groups (low polarity) make it difficult for polar PU paints to wet and spread on their surfaces. This results in poor paint film adhesion, easy peeling, and the formation of orange peel defects, which are detrimental to the manufacturing and application of in-mold painted parts on these non-polar substrates.

[0005] To improve the adhesion between non-polar substrates and polar paints, the substrate can be modified in bulk or on its surface to increase surface polarity and enhance its compatibility and interaction with the paint film. For example, PP can be blended and modified using ethylene-vinyl acetate, ethylene-acrylic acid cationic copolymer, and polyamide (PA6) powder (Chinese Invention Patent CN202410819064.8), and then a polyurethane paint film can be formed through integrated injection molding and in-mold coating. Alternatively, physical and chemical methods can be used to treat the surface of non-polar substrates, such as mechanical polishing to increase surface roughness, chemical etching, corona treatment, plasma treatment, or flame treatment to activate the substrate surface (Chinese Invention Patents CN202411043486.7, CN202411902011.9), and the use of adhesion promoters (such as chlorinated polypropylene-CPP), thereby improving the adhesion performance between non-polar substrates such as PP and the PU paint film.

[0006] However, modifying the substrate usually requires additional equipment and processes, such as using corona, nitrogen or air plasma equipment, which increases costs significantly. There are also problems such as poor compatibility with in-mold painting integrated molding automation processes and short surface activation time. Methods such as chemical etching, flame treatment, dissolution with organic solvents and spraying accelerators have an impact on safety and environmental protection, which is not conducive to large-scale production.

[0007] To improve the adhesion between non-polar substrates and polar paints, the paint film can be modified to reduce its polarity, increase its hydrophobicity, and enhance the wetting and interaction forces on the non-polar substrate surface. Currently, most methods for integrally molding polar paint films onto non-polar substrates are based on modifying the non-polar substrate to improve its adhesion to the polar paint film, with little focus on modifying the polar paint film itself, such as preparing low surface energy or hydrophobic polyurethane paint films to ensure strong adhesion to the non-polar substrate surface.

[0008] In the preparation of polyurethane, organosilicones (such as dihydroxy organosilicon, dihydroxy-terminated polyether modified silicone oil), siloxane coupling agents (such as fluorosilane coupling agents, silane coupling agents containing long-chain alkyl groups, CN201710763936.3), long-chain diluents (such as 12-18 alcohol, glyceryl monostearate with 18-alkyl side chains), and nanoparticles (such as carbon nanotubes, graphene, silica nanoparticles, CN202410652054.X) can be used to improve the hydrophobicity of polyurethane, thereby improving the adhesion between polyurethane sealants or primers and substrates (such as glass, aluminum plates, stainless steel, PP films, etc.). It can also be used to prepare block copolymer polyurethanes, such as polyether block polybutadiene-type polyurethanes prepared by hydroxyl-terminated polybutadiene, to obtain low surface energy film materials; and to prepare polyurethane adhesives with dopamine side chains by using functional compounds containing dopamine (such as dopamine dimethylolpropionamide-DMPA-DA chain extender, lysine dopamine-LDA, isocyanate-terminated dopamine bis(hydroxymethyl)propionate-DBHP), or by chain extension with acid-containing chain extenders followed by reaction with dopamine hydrochloride, to improve their adhesion to substrates (glass, aluminum alloys and stainless steel, etc.) or their waterproof adhesion ability underwater.

[0009] However, the adhesion of modified polyurethane to non-polar substrates (such as PP film) is still insufficient, requiring further methods such as plasma treatment to improve the adhesion. Furthermore, the preparation process of the aforementioned modified polyurethane typically involves multiple steps, long reaction and curing times (several hours), and the use of organic solvents such as acetone / ethyl acetate. The raw materials for preparing dopamine-containing polyurethane need to be prepared in-house, and the performance of the resulting polyurethane requires further improvement. All of these factors make it unsuitable for in-mold coating integrated molding processes. Therefore, it is necessary to develop high-performance polyurethane coatings that can rapidly wet, spread, cure, and firmly adhere to non-polar substrates without increasing the current in-mold coating equipment and processes. Summary of the Invention

[0010] To address the problems of weak adhesion between non-polar substrates and polar paints, the need for additional equipment and processes for surface modification of non-polar substrates, and the unsuitability of polyurethane modification for in-mold coating integrated molding processes (due to multiple steps, long processing time, the need for organic solvents, and the requirement for self-made raw materials), this invention provides a method for in-mold coating of hydrophobic polyurethane paint films on the surface of non-polar substrates.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for in-mold coating of a hydrophobic polyurethane film onto a non-polar substrate surface, comprising the following steps: Polyurethane paint A and polyurethane paint B are cured into a film on the surface of a non-polar substrate formed in a coating mold. The polyurethane paint A contains a catalyst, a polyol, and a polyphenol compound; The polyols include one or more of polyether polyols, polyester polyols, and polycarbonate polyols; The polyurethane coating B comprises component B1 and component B2; Component B1 is selected from one or more of the following: metal salts, functional organosilicones, silane coupling agents, long-chain alcohols with 12 to 18 alkyl groups, long-chain amines with 12 to 18 alkyl groups, nanoparticles, and flame retardants. Component B2 is a polyisocyanate.

[0012] Optionally, in the above method, the non-polar substrate includes one or more of polypropylene, glass fiber reinforced polypropylene composite material, carbon fiber reinforced polypropylene composite material, polystyrene, and polyethylene.

[0013] In the above method, the polyether polyol further includes one or more of polytetramethylene ether glycol 1000 (PTMEG-1000) and polypropylene glycol 1000 (PPG-1000); And / or, the polyester polyol includes one or more of polybutylene adipate (PBA) and polyhexylene adipate (PHA); And / or, the polycarbonate polyol includes one or more of poly(1,6-hexanediol carbonate) (PCDL-H) and poly(cyclohexanediol carbonate) diol (PCDL-C).

[0014] In the above method, the polyphenolic compound further includes one or more of dopamine (DA), tannic acid (TA), catechol (CAT), resveratrol (RE), and gallic acid (GA); And / or, the amount of the polyphenol compound used is 2 to 15 mol% (molar percentage) of the polyol.

[0015] In the above method, the polyisocyanate further includes one or more of aliphatic polyisocyanates and aromatic polyisocyanates; preferably, the aliphatic polyisocyanate includes one or more of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI); the aromatic polyisocyanate includes one or more of 4',4-diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI); And / or, the molar ratio of the polyisocyanate to the polyol in the polyurethane paint A is (4-1):1.

[0016] In the above method, the metal salt further includes one or more of copper sulfate (CuSO4), titanium sulfate (Ti(SO4)2), and zinc sulfate (ZnSO4); And / or, the amount of the metal salt used is 3 to 6 mol% (molar percentage) of the polyisocyanate; And / or, the functional organosilicon includes amino-terminated organosilicon (NH2-PDMS-NH2) and hydroxyl-terminated organosilicon (OH-PDMS-OH); And / or, the amount of the functional organosilicon is 3 to 10 mol% (molar percentage) of the polyisocyanate; And / or, the silane coupling agent comprises one or more of 3-aminopropyltriethoxysilane (APTES), n-octyltriethoxysilane (OTES), isocyanate-based trimethoxysilane (ICPTMS), 3-mercaptopropyltrimethoxysilane (TMSPT), and dihydroxydihydroxyalkylsiloxane (UC2862); And / or, the amount of the silane coupling agent is 4 to 10 mol% (molar percentage) of the polyisocyanate; And / or, the long-chain alcohol includes one or more of dodecyl alcohol, hexadecyl alcohol, and octadecyl alcohol; And / or, the long-chain amine includes one or more of dodecylamine, hexadecylamine, and octadecylamine; And / or, the amount of the long-chain alcohol or the long-chain amine is 5-10 mol% (mol percentage) of the polyisocyanate; And / or, the nanoparticles include one or more of carbon black (CB), carbon nanotubes (CNT), and graphene (GNP); And / or, the amount of the nanoparticles is 1 to 5 wt% (mass percentage) of the polyisocyanate; And / or, the flame retardant includes one or more of ammonium polyphosphate (APP) and potassium antimony tartrate (TE); And / or, the amount of the flame retardant is 1 to 5 wt% (mass percentage) of the polyisocyanate.

[0017] In the above method, the catalyst further comprises one or more of dibutyltin dilaurate (DBTDL), triethylenediamine (TEDA), and triethanolamine (TEA); And / or, the amount of the catalyst used is 0.1 to 1 mol% (molar percentage) of the polyol.

[0018] In the above method, the injection flow rate of the polyurethane paint A is further 20-40 ml / min; And / or, the injection flow rate of the polyurethane paint B is 40-88 ml / min; And / or, in the curing film-forming step, the curing temperature is 80–120°C; And / or, in the curing film-forming step, the curing time is 3 to 15 minutes.

[0019] Secondly, the present invention provides a method for preparing an in-mold coated non-polar material component, including the method of in-mold coating a hydrophobic polyurethane coating film on the surface of a non-polar substrate as described in any of the above.

[0020] Thirdly, the present invention provides an in-mold coated nonpolar material component prepared by the method described in any of the preceding claims.

[0021] The present invention has the following beneficial effects: (1) This invention improves the adhesion of polyurethane coating film to non-polar substrate surface by modifying the polyurethane coating film without increasing the equipment and processes used in the current in-mold painting integrated molding process. It is simple, fast, economical and efficient. At the same time, it uses solvent-free paint system and commercial raw materials, which is safe and environmentally friendly. (2) This invention utilizes the hydrogen bonding and π-π stacking effect formed by the phenolic hydroxyl structure of polyphenolic compounds, as well as the synergistic effect of metal salts and polyphenolic compounds, to improve the anchoring and adhesion of polyurethane coatings on non-polar substrate surfaces; utilizes silane coupling agents to improve the wettability of the coating on non-polar substrate surfaces and the adhesion of the coating film on non-polar substrate surfaces; utilizes the hydrophobic segments or structures of organosilicon, silane coupling agents, long-chain alcohols or amines, nanoparticles, etc., to improve the wettability and spreadability of the coating on non-polar substrate surfaces and to improve the adhesion of the coating film (the static water contact angle of the coating film surface increases from 30-45° to 85-115°). The adhesive strength of the paint film is increased by 80-839%. The reaction of polyphenolic compounds, organosilicon, silane coupling agents, long-chain alcohols, or amines with isocyanates promotes cross-linking, effectively improving the strength and toughness of the paint film (tensile strength increased by 30-315%, impact strength increased by 10-275%), reducing water absorption (water absorption rate reduced by 5-35%), and achieving a better flame-retardant effect (LOI value increased by 3-25%). The combined synergistic effect results in excellent overall performance of the paint film, which is highly beneficial for the practical application of in-mold painted integrally molded parts. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0026] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range.

[0027] Furthermore, when multiple scopes are provided to describe a feature or characteristic, these scopes may be merged. In other words, unless otherwise specified, all scopes disclosed herein should be understood to include any and all subscopes to which they are included. Additionally, in the description of the invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In its first part, this invention provides a method for in-mold coating of a hydrophobic polyurethane film onto a non-polar substrate surface, comprising the following steps: Polyurethane paint A and polyurethane paint B are cured into a film on the surface of a non-polar substrate formed in a coating mold. The polyurethane paint A contains a catalyst, a polyol, and a polyphenol compound; The polyols include one or more of polyether polyols, polyester polyols, and polycarbonate polyols; The polyurethane coating B comprises component B1 and component B2; Component B1 is selected from one or more of the following: metal salts, functional organosilicones, silane coupling agents, long-chain alcohols with 12 to 18 alkyl groups, long-chain amines with 12 to 18 alkyl groups, nanoparticles, and flame retardants. Component B2 is a polyisocyanate.

[0029] Based on the above technical solutions, this invention provides a method for preparing hydrophobic polyurethane coatings using the synergistic effects of polyphenolic compounds, metal salts, functional organosilicones and silane coupling agents, long-chain alcohols or amines, nanoparticles, flame retardants, etc. This method does not increase the equipment and processes used in current in-mold painting integrated molding processes, uses a solvent-free paint system, and is safe and environmentally friendly. The paint can be quickly spread, cured, and form a firmly adhered paint film on the surface of non-polar substrates, maintaining the original integrated molding process cycle. The prepared paint film has a smooth surface, adhesion of 0 or 1 grade, improved mechanical properties, reduced water absorption, and improved flame retardant properties.

[0030] According to embodiments of the present invention, the non-polar material includes one or more of polypropylene, glass fiber reinforced polypropylene composite material, carbon fiber reinforced polypropylene composite material, polystyrene, and polyethylene.

[0031] According to embodiments of the present invention, the polyether polyol comprises one or more of polytetramethylene ether glycol 1000 (PTMEG-1000) and polypropylene glycol 1000 (PPG-1000). The polyester polyol comprises one or more of polybutylene adipate (PBA) and polyhexyl adipate (PHA). The polycarbonate polyol comprises one or more of poly(1,6-hexanediol carbonate) (PCDL-H) and poly(cyclohexanediol carbonate) diol (PCDL-C). Formulated PU-A components can be used, or commercially available polyol components for polyurethane production can be used, including RIM-Surface 8001-A (Liming Chemical Research Institute) or HL80699 (Wanhua Chemical Group Co., Ltd.). Commercially available components contain catalysts.

[0032] According to embodiments of the present invention, the polyphenolic compound includes one or more of dopamine (DA), tannic acid (TA), catechol (CAT), resveratrol (RE), and gallic acid (GA). The amount of the polyphenolic compound used is 2 to 15 mol% (molar percentage) of the polyol, including but not limited to 14 mol%, 10 mol%, 2 mol%, 4 mol%, 8 mol%, 2 mol%, and 12 mol%.

[0033] According to embodiments of the present invention, the polyisocyanate includes one or more of aliphatic polyisocyanates and aromatic polyisocyanates; preferably, the aliphatic polyisocyanate includes one or more of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI); the aromatic polyisocyanate includes one or more of 4',4-diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI). The molar ratio of the polyisocyanate to the polyol in the polyurethane paint A is (4-1):1, including but not limited to 2:1, 1:1, 3.6:1, 3.5:1, 4:1, and 3:1. Formulated polyisocyanates can be used, or commercially available polyisocyanate-containing components, including RIM-Surface 8001-B (Liming Chemical Research Institute) or HL699 (Wanhua Chemical Group Co., Ltd.), can be used.

[0034] According to an embodiment of the present invention, the metal salt includes one or more of copper sulfate (CuSO4), titanium sulfate (Ti(SO4)2), and zinc sulfate (ZnSO4); the amount of the metal salt is 3 to 6 mol% (molar percentage) of the polyisocyanate, including but not limited to 6 mol%, 3 mol%, and 4 mol%.

[0035] According to an embodiment of the present invention, the functional organosilicon includes amino-terminated organosilicon (NH2-PDMS-NH2) and hydroxyl-terminated organosilicon (OH-PDMS-OH); the amount of the functional organosilicon is 3 to 10 mol% (molar percentage) of the polyisocyanate, including but not limited to 10 mol%, 9 mol%, and 3 mol%.

[0036] According to embodiments of the present invention, the silane coupling agent comprises one or more of 3-aminopropyltriethoxysilane (APTES), n-octyltriethoxysilane (OTES), isocyanate-based trimethoxysilane (ICPTMS), 3-mercaptopropyltrimethoxysilane (TMSPT), and dihydroxydihydroxyalkylsiloxane (UC2862); the amount of the silane coupling agent is 4 to 10 mol% (molar percentage) of the polyisocyanate, including but not limited to 8 mol%, 4 mol%, and 5 wt%.

[0037] According to an embodiment of the present invention, the long-chain alcohol includes one or more of dodecyl alcohol, hexadecyl alcohol, and octadecyl alcohol; the long-chain amine includes one or more of dodecylamine, hexadecylamine, and octadecylamine; the amount of the long-chain alcohol or the long-chain amine is 5 to 10 mol% (molar percentage) of the polyisocyanate, including but not limited to 8 mol%, 10 mol%, and 5 mol%.

[0038] According to an embodiment of the present invention, the nanoparticles include one or more of carbon black (CB), carbon nanotubes (CNT), and graphene (GNP); the amount of the nanoparticles is 1 to 5 wt% (mass percentage) of the polyisocyanate, including but not limited to 1 wt%, 3 wt%, and 5 wt%.

[0039] According to an embodiment of the present invention, the flame retardant includes one or more of ammonium polyphosphate (APP) and potassium antimony tartrate (TE); the amount of the flame retardant is 1 to 5 wt% (mass percentage) of the polyisocyanate, including but not limited to 1 wt% and 5 wt%.

[0040] According to an embodiment of the present invention, the catalyst comprises one or more of dibutyltin dilaurate (DBTDL), triethylenediamine (TEDA), and triethanolamine (TEA); the amount of the catalyst is 0.1 to 1 mol% (molar percentage) of the polyol, including but not limited to 0.1% mol%, 0.5 mol%, 1 mol%, and 0.7 mol%.

[0041] According to an embodiment of the present invention, the injection flow rate of the polyurethane paint A is 20–40 ml / min, including but not limited to 20 ml / min, 30 ml / min, 25 ml / min, and 40 ml / min; the injection flow rate of the polyurethane paint B is 40–88 ml / min, including but not limited to 60 ml / min, 40 ml / min, 50 ml / min, 88 ml / min, and 66 ml / min. In the curing and film-forming step, the curing temperature is 80–120°C, including but not limited to 120°C, 100°C, 90°C, and 80°C, and the curing time is 3–15 min, including but not limited to 8 min, 9 min, 7 min, 15 min, and 12 min.

[0042] According to an embodiment of the present invention, the operation steps of the method include: S1. Prepare paint A and paint B separately: Specifically, dissolve the polyphenol compound in the polyol under stirring to prepare polyurethane paint component A (PU-A); dissolve or disperse one or more components selected from metal salt, functional organosilicon, silane coupling agent, long-chain alcohol or amine, nanoparticles, and flame retardant in polyisocyanate to prepare polyurethane paint component B (PU-B); heat the prepared paint components A and B to a certain temperature; S2. Set the mold cavity of the injection molding and subsequent transfer mold to a certain temperature. Add a catalyst to paint component A. Mix paint A and paint B at a certain flow rate through a mixing nozzle until homogeneous, then inject into the mold cavity and spray onto the surface of a non-polar substrate. Cure on the substrate surface for a certain time to form a film, then open the mold and remove the sample. Specifically, the mold cavity temperature is set at the curing temperature, such as 80-120°C.

[0043] It is understood that the device used in this invention can be the same as that used in conventional in-mold painting integrated molding technology. For example, the device includes a storage device, a feeding device, a mixing nozzle and a painting mold. In use, polyurethane paint A and polyurethane paint B are injected into the painting mold respectively, mixed by the mixing nozzle, and then injected into the painting mold to cure into a film on the surface of the non-polar substrate.

[0044] According to an embodiment of the present invention, the painting molding mold includes a cavity and a punch that are matched with each other, and the cavity is provided with a cavity. In the present invention, the painting molding mold refers to a mold that can realize an in-mold painting integrated molding process, including but not limited to the molds with the structures shown in CN202310741313.1 and CN202310793686.3.

[0045] In the second part, the present invention provides a method for preparing an in-mold coated non-polar material component, including the method of in-mold coating a hydrophobic polyurethane coating film on the surface of a non-polar substrate as described in any of the above.

[0046] In this invention, the sample after curing and mold opening has a smooth paint film surface, a static water contact angle of 85-115°, a paint film adhesion level of 0 or 1, an increase in the bonding strength between the paint film and the non-polar substrate surface by 80-839%, an increase in the tensile strength of the paint film by 30-315%, an increase in the impact strength by 10-275%, a decrease in water absorption by 5-35%, and an increase in the flame retardant oxygen index by 3-25%.

[0047] Thirdly, the present invention provides an in-mold coated nonpolar material component prepared by the method described in any of the preceding claims.

[0048] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0049] Unless otherwise specified, the methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0050] In the following embodiments, a contact angle meter was used to measure the static water contact angle of the surface, the cross-cut adhesion method was used to determine the coating film adhesion level, the overlap shear test method was used to test the bond strength between the coating film and the substrate, the tensile and impact tests were used to measure the mechanical properties of the polyurethane coating film, the water absorption rate test method was used to test the water absorption of the coating film, and the limiting oxygen index method was used to test the flame retardancy of the coating film. The specific test methods are as follows: Water contact angle determination: The water contact angle of the sample surface was measured using an OCA20 contact angle meter according to the method of GB_T 30693-2014. The average value of the measured values ​​at 10 test points was calculated. Paint film adhesion test: The paint film adhesion grade was determined by cross-cut test according to ISO 2409:2007 standard. Cross-cut test appearance: Adhere 3M tape to the surface of the paint film after the cross-cut test, peel off the tape at a 60° angle to the surface, and observe the paint film peeling off the surface. Bond strength test: The lap shear test was adopted. The sample size was 100 × 25 mm, and the size of the adhesive part was 12.5 × 25 mm. According to GB / T 33334-2016, the lap shear strength was tested using a universal testing machine at a speed of 10 mm / min.

[0051] Tensile strength test: According to the requirements of GB / T1040.4-2006 standard, a dumbbell-shaped polyurethane coating strip with a span of 50mm, a width of 5mm, and a thickness of 0.3mm was tested using a universal testing machine at a tensile speed of 10mm / min. Impact strength test: According to the requirements of GB / T 1043.1-2008 standard, the XJJD simply supported beam impact testing machine was used to test a polyurethane strip with a length of 80mm, a width of 10mm and a thickness of 1mm. Water absorption test: Cut the completely dried polyurethane film into 20 × 20 mm pieces and weigh them (W0); immerse them in water at room temperature for 24 h, remove them, wipe off the water on the film surface with absorbent paper, weigh them (W1), and calculate the water absorption rate (mass fraction) of the polyurethane film in water. The calculation formula is as follows: Water absorption rate (%) = (W1 - W0) / W0 × 100%; Flame retardant oxygen index (LOI) determination: According to ISO 4589-2 standard requirements, using an HC-2C oxygen index tester, for a flame retardant sample measuring 100×10×3mm... 3 The oxygen index of the PU coating film was tested.

[0052] Example 1 This embodiment provides a method for in-mold coating (hydrophobic polyurethane) on a non-polar substrate, the specific steps of which are as follows: S1 - Preparing paint: Tannic acid (TA, 11.9 g, 0.007 mol, 14 mol of PTMEG-1000) was dissolved in polytetramethylene ether glycol (PTMEG-1000, 50 g, 0.05 mol) under stirring to prepare polyurethane paint component A (PU-A). The mixture was heated to 120°C, and dibutyltin dilaurate (DBTDL, 0.03 g, 0.05 mmol, 0.1 mol of PU-A component) was added as a catalyst. The mixture was stirred and mixed thoroughly for later use. Hydroxyl-terminated organosilicon (OH-PDMS-OH, 20 g, 0.01 mol, 10 mol% of IPDI) was dissolved in isophorone diisocyanate (IPDI, 22.5 g, 0.1 mol, PTMEG-1000 / IPDI = 1:2 mol ratio) to prepare polyurethane paint component B (PU-B), and the mixture was heated to 120°C. S2 - In-mold painting The injection molding and subsequent mold cavity is set at 120°C. PU-A component is injected at a flow rate of 20 ml / min and PU-B component at a flow rate of 60 ml / min. After being mixed through a mixing nozzle, the mixture is injected into the mold cavity and sprayed onto the surface of the polypropylene (PP) substrate. The film is cured for 8 minutes, and then the mold is opened and the sample is taken out. The obtained sample had a static water contact angle of 110°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. A polyurethane paint film was prepared using PTMEG-1000 and IPDI as a control. The paint film prepared in this example showed a 450% increase in bonding strength between the paint film and PP, a 150% increase in tensile strength, a 200% increase in impact strength, an 8% decrease in water absorption, and a 15% increase in LOI value.

[0053] Example 2 As in Example 1, except that in the S1-preparation process of the paint, when preparing the PU-A component, CAT (0.56g, 0.005mol, 10mol% of PPG-1000) is dissolved in polypropylene glycol 1000 (PPG-1000, 50g, 0.05mol); when preparing the PU-B component, 18-amine (C 18 NH2, 2.7 g, 0.01 mol (8 mol% of TDI) dissolved in toluene diisocyanate (TDI, 17.4 g, 0.1 mol, PPG-1000 / TDI = 1:2 mol ratio). During the S2-in-mold painting process, the paint curing time was 9 min.

[0054] The obtained sample had a static water contact angle of 115°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. A polyurethane paint film was prepared using PPG-1000 and TDI as a control. The paint film prepared in this example showed a 210% increase in bonding strength between the paint film and PP, a 30% increase in tensile strength, a 25% increase in impact strength, a 5% decrease in water absorption, and a 10% increase in LOI value.

[0055] Example 3 As in Example 1, except that in S1—the paint preparation process—when preparing the PU-A component, dopamine (DA, 0.8 g, 0.005 mol, 10 mol% of PHA) was dissolved in polyhexyl adipate (PHA, 13.2 g, 0.05 mol); and when preparing the PU-B component, n-octyltrioxyethylsilane (OTES, 1.8 g, 0.008 mol, 9 mol% of MDI) was dissolved in 4',4-diphenylmethane diisocyanate (MDI, 17.4 g, 0.1 mol, PHA / MDI = 1:2 mol ratio). In S2—the in-mold painting process—the paint curing time was 7 min. The static water contact angle of the obtained sample surface is 95°, the paint film adhesion level is 0, and there is no peeling in the cross-cut adhesion test. Using PHA and MDI to prepare polyurethane paint film as a control sample, the paint film prepared in this example has a 385% higher bonding strength with PP, an 80% higher tensile strength, a 65% higher impact strength, a 20% lower water absorption rate, and an 8% higher LOI value.

[0056] Example 4 As in Example 1, except that in the S1-process of preparing the paint, when preparing the PU-A component, gallic acid (GA, 1.7 g, 0.01 mol, 10 mol% of PBA) is dissolved in polybutylene adipate (PBA, 18.2 g, 0.1 mol), heated to 100°C, and the catalyst triethylenediamine (TEDA, 0.056 g, 0.5 mmol, 0.5 mol% of PU-A component) is added; when preparing the PU-B component, carbon black (CB, g, 0.84, 5 wt% of HDI) is dissolved in hexamethylene diisocyanate (HDI, 16.8 g, 0.1 mol, PBA / HDI = 1:1 mol ratio), and heated to 100°C. During the S2-in-mold painting process, the mold cavity temperature is 100°C, the injection flow rate of PU-A component is 30ml / min, the volume injection flow rate of PU-B component is 60ml / min, the substrate is polyethylene (PE), and the curing time of PU paint is 15 min. The static water contact angle of the obtained sample surface is 105°, the paint film adhesion level is 0, and there is no peeling in the cross-cut adhesion test. Using PBA and HDI to prepare polyurethane paint film as a control sample, the adhesion strength between the paint film and PE prepared in this embodiment is increased by 315%, the tensile strength of the paint film is increased by 90%, the impact strength is increased by 80%, the water absorption rate is reduced by 12%, and the LOI value is increased by 15%.

[0057] Example 5 As in Example 1, except that in the S1-process of preparing the paint, when preparing the PU-A component, resveratrol (RE, 2.3 g, 0.01 mol, 10 mol% of PCDL-H) is dissolved in polybutylene adipate (PCDL-H, 33.2 g, 0.1 mol), heated to 100°C, and the catalyst triethanolamine (TEA, 0.075 g, 0.5 mmol, 0.5 mol% of PU-A component) is added; when preparing the PU-B component, 12-ol and 16-amine (C 12 OH and C 16NH2 (10 mol%) of IPDI was dissolved in IPDI (79.9 g, 0.36 mol, PDCL-H / IPDI = 1:3.6 mol ratio), and the temperature was raised to 100°C. During the S2-in-mold coating process, the mold cavity temperature was 100°C, the substrate was carbon fiber reinforced polypropylene composite (CF / PP), and the PU paint curing time was 12 min. The obtained sample surface had a static water contact angle of 104°, a paint film adhesion grade of 1, and less than 5% appearance peeling in the cross-cut adhesion test. The polyurethane paint film prepared using PCDL-H and IPDI was used as a control sample. The paint film prepared in this example showed an 80% increase in bonding strength between the paint film and CF / PP, a 30% increase in tensile strength, a 30% increase in impact strength, a 6% decrease in water absorption, and a 5% increase in LOI value.

[0058] Example 6 As in Example 1, except that in S1 - the paint preparation process, when preparing the PU-A component, TA (3.4g, 0.0002mol, 2mol% of PPG-1000 and PDCL-H) is dissolved in PPG-1000 and PDCL-H (100g, 0.1mol); zinc sulfate (ZnSO4, 0.021mol, 3.4g) is dispersed in TDI (61g, 0.35mol, (PPG-100, PDCL-H):TDI = 1:3.5 mol ratio); in S2 - the in-mold painting process, the injection flow rate of the PU-A component is 30ml / min, the injection flow rate of the PU-B component is 60ml / min, the substrate is CF / PP, and the paint curing time is 10min; The obtained sample had a static water contact angle of 88°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. Polyurethane paint films were prepared using PPG-1000, PCDL-H, and IPDI as control samples. The paint film prepared in this example showed a 220% increase in bond strength between the paint film and CF / PP, a 50% increase in tensile strength, a 15% increase in impact strength, a 10% decrease in water absorption, and a 15% increase in LOI value.

[0059] Example 7 As in Example 1, except that in S1 - the paint preparation process, when preparing the PU-A component, TE and DA (0.08g, 0.004mol, 4mol% of PTEG-1000 and PBA) are dissolved in PTMEG-1000 and PBA (110g, 0.1mol), and TEA (0.075g, 0.05mmol, 0.5mol% of PU-A component) is added as a catalyst; ammonium polyphosphate (APP, 0.6g, 1wt% of HDI) is dissolved in HDI (60.5g, 0.36mol, PTMEG, PBA:HDI = 1:3.6mol ratio); in S2 - the in-mold painting process, the injection flow rate of the PU-A component is 20ml / min, the injection flow rate of the PU-B component is 40ml / min, the substrate is CF / PP, and the paint curing time is 15min; The obtained sample had a static water contact angle of 95°, a paint film adhesion grade of 1, and less than 5% of the appearance peeling was observed in the cross-cut adhesion test. Polyurethane paint films were prepared using PTMEG-1000, PBA, and HDI as control samples. The paint film prepared in this example showed a 120% increase in bond strength between the paint film and CF / PP, a 30% increase in tensile strength, a 70% increase in impact strength, a 18% decrease in water absorption, and an 8% increase in LOI value.

[0060] Example 8 As in Example 1, except that in S1 - during the preparation of the paint, when preparing the PU-A component, TA and DA (3.7g, 0.004mol, 4mol% of PBA and PDCL-H) were dissolved in PBA and PDCL-H (100g, 0.1mol), and catalyst TEDA (0.11g, 1mmol, 1% of PU-A component) was added, and the temperature was raised to 100°C; 3-aminopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane (APTES and TMSPT, 0.028mol, 8mol% of IPDI) were dispersed in IPDI (61g, 0.35mol, (PBA, PDCL-H):IPDI = 1:3.5mol ratio). In S2 - during the in-mold painting process, the mold cavity temperature was [temperature missing], the injection flow rate of the PU-A component was 25ml / min, the injection flow rate of the PU-B component was 50ml / min, and the substrate was polystyrene (PS). The obtained sample had a static water contact angle of 115°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. A polyurethane paint film was prepared using PPG-1000, PCDL-H, and IPDI as a control. The overlap shear test of the paint film prepared in this example showed a 236% increase in bond strength between the paint film and PS, a 60% increase in tensile strength, a 100% increase in impact strength, a 35% decrease in water absorption, and a 10% increase in LOI value.

[0061] Example 9 As in Example 1, except that in S1 - the paint preparation process, GA and CAT (1.4g, 0.01mol, 10mol% of PTMGE-1000) were dissolved in PTMGE-1000 (100g, 0.1mol), and the catalyst DBTDL (0.31g, 0.5mmol, 0.5mol% of PU-A component) was added. The temperature was raised to 100°C. Titanium sulfate (Ti(SO4)2, 1.9g, 0.02mol, 6mol% of (TDI, HDI)) and carbon nanotubes (CNT, 0.34g, 1wtl% of (TDI, HDI)) were dispersed in TDI and HDI (34.2g, 0.2mol), and the temperature was raised to 100°C. In S2 - the in-mold painting process, the mold cavity temperature was 100°C, the substrate was PS, the curing temperature was 100°C, and the paint curing time was 7min. The obtained sample had a static water contact angle of 110°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. Polyurethane paint films were prepared using PTMGE-1000, HDI, and TDI as control samples. The overlap shear test of the paint film prepared in this example showed a 300% increase in bond strength between the paint film and PS, a 130% increase in tensile strength, a 152% increase in impact strength, a 35% decrease in water absorption, and a 25% increase in LOI value.

[0062] Example 10 As in Example 1, except that in the S1-preparation of the paint, TA and RE (9.6g, 0.005mol, 10mol% of PCDL-C) were dissolved in poly(cyclohexanediol carbonate) ester diol (PCDL-C, 100g, 0.1mol), and catalyst TEA (0.07g, 0.5mmol, 0.5mol% of PCDL-C) was added. The temperature was raised to 100°C, and 16-ol (C 16 OH, 4.2g, 0.0175mmol, 5mol% of HDI, PCDL-C:HDI = 1:3.5mol ratio), potassium antimony tartrate (TE, 2.9g, 5wt% of HDI) dissolved in HDI (58.8g, 0.35mol), heated to 100°C; during the S2-in-mold painting process, the mold cavity temperature was 100°C, the injection flow rate of PU-A component was 30ml / min, the injection flow rate of PU-B component was 50ml / min, the substrate was PS, the curing temperature was 100°C, and the paint curing time was 15min; The obtained sample had a static water contact angle of 98°, a paint film adhesion grade of 0, and no peeling in the cross-cut adhesion test. A polyurethane paint film was prepared using PCDL-C and HDI as a control. The overlap shear test of the paint film prepared in this example showed an increase of 238% in the bonding strength between the paint film and PS, an increase of 125% in the tensile strength of the paint film, an increase of 95% in the impact strength, a decrease of 12% in the water absorption rate, and an increase of 10% in the LOI value.

[0063] Example 11 As in Example 1, except that in the S1-preparation of the paint, DA (0.004 mol, 4 mol% of PBA) is dissolved in PBA (100 g, 0.1 mol), the temperature is raised to 90°C, and zinc sulfate (ZnSO4) is added. 4, 0.5g, 0.003mol, 3mol% of IPDI and HDI, dihydroxydihydroxyalkylsiloxane (UC2862, 0.004mol, 4mol% of IPDI and HDI) dissolved in IPDI and HDI (58.5g, 0.3mol, PBA:(IPDI,HDI)=1:3), heated to 90°C; during the S2-in-mold painting process, the mold cavity temperature was 90°C, the injection flow rate of PU-A component was 30ml / min, the injection flow rate of PU-B component was 50ml / min, the substrate was PS, and the paint curing time was 15min; The obtained sample had a static water contact angle of 105°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. A polyurethane paint film was prepared using PCDL-C and HDI as a control. The overlap shear test of the paint film prepared in this example showed an increase of 165% in bond strength between the paint film and PS, an increase of 40% in tensile strength, an increase of 35% in impact strength, a decrease of 26% in water absorption, and an increase of 3% in LOI value.

[0064] Example 12 As in Example 1, except that in the S1-preparation of the paint, TA (3.4g, 0.002mol, 2mol% of RIM Surface 8001A) is dissolved in RIM Surface 8001 A (100g), catalyst DBTDL (0.3g, 0.5mmol, 0.5mol% of PU-A component) is added, the temperature is raised to 90°C, and isocyanate-based trimethoxysilane (ICPTMC, 1.9g, 0.01mol, 4mol% of RIM Surface 8001 B) and APP (11.5g, 5wt% of RIM Surface 8001 B) are dissolved in RIM Surface 8001 B (230g, RIM Surface 8001 A: RIM Surface 8001 B). B=1:2.3), heated to 90°C; during the S2-in-mold painting process, the mold cavity temperature was 90°C, the injection flow rate of PU-A component was 40ml / min, the injection flow rate of PU-B component was 88ml / min, the substrate was glass fiber reinforced polypropylene composite material (GF / PP), the curing temperature was 90°C, and the paint curing rate was 10min; The obtained sample had a static water contact angle of 108°, a paint film adhesion rating of 0, and no peeling during the cross-cut adhesion test. Polyurethane paint films were prepared using RIM Surface 8001A and RIM Surface 8001B as control samples. The lap shear test bond strength between the paint film prepared in this example and GF / PP was increased by 193%, the tensile strength of the paint film was increased by 120%, the impact strength was increased by 43%, the water absorption rate was reduced by 32%, and the LOI value was increased by 13%.

[0065] Example 13 As in Example 1, except that in the S1-preparation of the paint, TA (13.6g, 0.008mol, 8mol% of RIM Surface 8001A) was dissolved in RIM Surface 8001 A (100g), and catalyst DBTDL (0.42g, 0.7mol, 0.7mol% of PU-A component) was added. The temperature was raised to 90°C, and graphene (GNP, 9g, 3wt% of RIM Surface 8001B) and 18-ol (C 18OH, 8.1g, 0.01mol, 10mol%) of RIM Surface 8001B was dissolved in RIM Surface 8001 B (300g, RIM Surface 8001 A: RIM Surface 8001 B=1:3), and the temperature was raised to 90°C; during the S2-in-mold painting process, the mold cavity temperature was 90°C, the injection flow rate of PU-A component was 20ml / min, the injection flow rate of PU-B component was 44ml / min, the substrate was CF / PP, and the paint curing time was 6min; The obtained sample had a static water contact angle of 103°, a paint film adhesion rating of 0, and no peeling during the cross-cut adhesion test. Polyurethane paint films were prepared using RIM Surface 8001A and RIM Surface 8001B as control samples. The lap shear test bond strength between the paint film prepared in this example and CF / PP was increased by 210%, the tensile strength of the paint film was increased by 80%, the impact strength was increased by 74%, the water absorption rate was reduced by 30%, and the LOI value was increased by 15%.

[0066] Example 14 As in Example 1, except that in the S1-preparation of the paint, TA (20.4g, 0.012mol, 12mol% of RIM Surface8001A) is dissolved in RIM Surface 8001 A (100g), catalyst DBTDL (0.42g, 0.7mol, 0.7mol% of PU-A component) is added, the temperature is raised to 100°C, and copper sulfate (CuSO4, 1.9g, 0.012mol, 3mol% of RIM Surface8001B) and diamino-terminated organosilicon (NH2-PDMS-NH2, 30g, 0.012mol, 3mol% of RIM Surface8001B) are dissolved in RIM Surface 8001 B (400g, RIM Surface 8001 A: RIM Surface8001) B=1:4), heat to 100°C; during the S2-in-mold painting process, the mold cavity temperature is 100°C, the injection flow rate of PU-A component is 30ml / min, the injection flow rate of PU-B component is 66ml / min, the substrate is GF / PP, and the paint curing time is 3min. The obtained sample surface had a static water contact angle of 95°, a paint film adhesion grade of 0, and no peeling during the cross-cut adhesion test. Polyurethane paint films were prepared using RIM Surface 8001A and RIM Surface 8001B as control samples. The lap shear test bond strength between the paint film prepared in this example and GF / PP was improved by 839%, the tensile strength of the paint film was improved by 315%, the impact strength was improved by 275%, the water absorption rate was reduced by 35%, and the LOI value was improved by 13%.

[0067] Example 15 As in Example 1, except that in the S1-preparation of the paint, GA (1.7g, 0.01mol, 10mol% of HL80699) was dissolved in HL80699 (0.1mol), and the catalyst DBTDL (0.3g, 0.5mmol, 0.5mol% of PU-A component) was added. The temperature was raised to 80°C, and 12-amine (C 12 NH2, 38.9g, 0.21mol, 8mol% of HL699, and CB (5wt% of HL699) were dissolved and dispersed in HL699 (0.21mol, HL80699:HL699=1:2.1), and the temperature was raised to 80°C. During the S2-in-mold painting process, the mold cavity temperature was 80°C, the substrate was PE, and the paint curing time was 15min. The obtained sample surface had a static water contact angle of 85°, a paint film adhesion grade of 0, and no peeling in the cross-cut adhesion test. Polyurethane paint films were prepared using HL80699 and HL699 as control samples. The overlap shear test of the paint film prepared in this example showed an increase of 103% in bond strength between the paint film and PE, an increase of 10% in tensile strength, an increase of 30% in impact strength, a decrease of 25% in water absorption, and an increase of 12% in LOI value.

[0068] Example 16 As in Example 1, except that in S1 - the paint preparation process, TA and RE (9.6g, 0.01mol, 10mol% of HL80699) were dissolved in HL80699 (0.1mol), and the catalyst DBTDL (0.3g, 0.5mmol, 0.5mol% of PU-A component) was added, and the temperature was raised to 80°C. CuSO4 (1.9g, 0.012mol, 4mol% of HL699) and CNT (5wt% of HL699) were dissolved and dispersed in HL699 (0.3mol, HL80699:HL699=1:3), and the temperature was raised to 80°C. In S2 - the in-mold painting process, the mold cavity temperature was 80°C, the substrate was PE, and the paint curing time was 15min. The static water contact angle of the obtained sample surface was 103°, the paint film adhesion grade was 0, and there was no peeling in the cross-cut adhesion test. Polyurethane paint films were prepared using HL80699 and HL699 as control samples. The overlap shear test bond strength between the paint film and PE prepared in this embodiment was increased by 215%, the tensile strength of the paint film was increased by 217%, the impact strength was increased by 174%, the water absorption rate was reduced by 23%, and the LOI value was increased by 23%.

[0069] The implementation effects of different embodiments are shown in Table 1.

[0070] Table 1. Implementation effects of different embodiments

[0071] As shown in Table 1, the method of the present invention does not require additional equipment or processes in the in-mold coating integrated molding process, and achieves wetting, spreading, rapid curing and firm adhesion of polyurethane coating film on the surface of non-polar substrate. The surface of the coating film of the prepared sample is smooth, the static water contact angle of the surface reaches 85-115°, the adhesion force of the coating film reaches level 0 and 1, the bonding strength between the coating film and the surface of non-polar substrate is increased by 80-839%, the tensile strength of the coating film is increased by 30-315%, the impact strength is increased by 10-275%, the water absorption rate is reduced by 5-35%, and the flame retardant oxygen index is increased by 3-25%.

[0072] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for in-mold coating a hydrophobic polyurethane film onto a non-polar substrate surface, characterized in that, Includes the following steps: Polyurethane paint A and polyurethane paint B are cured into a film on the surface of a non-polar substrate formed in a coating mold. The polyurethane paint A contains a catalyst, a polyol, and a polyphenol compound; The polyols include one or more of polyether polyols, polyester polyols, and polycarbonate polyols; The polyurethane coating B comprises component B1 and component B2; Component B1 is selected from one or more of the following: metal salts, functional organosilicones, silane coupling agents, long-chain alcohols with 12 to 18 alkyl groups, long-chain amines with 12 to 18 alkyl groups, nanoparticles, and flame retardants. Component B2 is a polyisocyanate.

2. The method according to claim 1, characterized in that: The non-polar substrate includes one or more of polypropylene, glass fiber reinforced polypropylene composite material, carbon fiber reinforced polypropylene composite material, polystyrene, and polyethylene.

3. The method according to any one of claims 1-2, characterized in that: The polyether polyol includes one or more of polytetramethylene ether glycol 1000 (PTMEG-1000) and polypropylene glycol 1000 (PPG-1000); And / or, the polyester polyol includes one or more of polybutylene adipate (PBA) and polyhexyl adipate (PHA); And / or, the polycarbonate polyol includes one or more of poly(1,6-hexanediol carbonate) (PCDL-H) and poly(cyclohexanediol carbonate) diol (PCDL-C).

4. The method according to any one of claims 1-3, characterized in that: The polyphenolic compounds include one or more of dopamine (DA), tannic acid (TA), catechol (CAT), resveratrol (RE), and gallic acid (GA); And / or, the amount of the polyphenol compound used is 2 to 15 mol% (molar percentage) of the polyol.

5. The method according to any one of claims 1-4, characterized in that: The polyisocyanate includes one or more of aliphatic polyisocyanates and aromatic polyisocyanates; preferably, the aliphatic polyisocyanate includes one or more of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI); the aromatic polyisocyanate includes one or more of 4',4-diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI). And / or, the molar ratio of the polyisocyanate to the polyol in the polyurethane paint A is (4~1):

1.

6. The method according to any one of claims 1-5, characterized in that: The metal salt includes one or more of copper sulfate (CuSO4), titanium sulfate (Ti(SO4)2), and zinc sulfate (ZnSO4); And / or, the amount of the metal salt used is 3 to 6 mol% (molar percentage) of the polyisocyanate; And / or, the functional organosilicon includes double-amino-terminated organosilicon (NH2-PDMS-NH2) and double-hydroxy-terminated organosilicon (OH-PDMS-OH); And / or, the amount of the functional organosilicon is 3 to 10 mol% (molar percentage) of the polyisocyanate; And / or, the silane coupling agent comprises one or more of 3-aminopropyltriethoxysilane (APTES), n-octyltriethoxysilane (OTES), isocyanate-based trimethoxysilane (ICPTMS), 3-mercaptopropyltrimethoxysilane (TMSPT), and dihydroxydihydroxyalkylsiloxane (UC2862); And / or, the amount of the silane coupling agent is 4 to 10 mol% (molar percentage) of the polyisocyanate; And / or, the long-chain alcohol includes one or more of dodecyl alcohol, hexadecyl alcohol, and octadecyl alcohol; And / or, the long-chain amine includes one or more of dodecylamine, hexadecylamine, and octadecylamine; And / or, the amount of the long-chain alcohol or the long-chain amine is 5-10 mol% (mol percentage) of the polyisocyanate; And / or, the nanoparticles include one or more of carbon black (CB), carbon nanotubes (CNT), and graphene (GNP); And / or, the amount of the nanoparticles is 1 to 5 wt% (mass percentage) of the polyisocyanate; And / or, the flame retardant includes one or more of ammonium polyphosphate (APP) and potassium antimony tartrate (TE); And / or, the amount of the flame retardant is 1 to 5 wt% (mass percentage) of the polyisocyanate.

7. The method according to any one of claims 1-6, characterized in that: The catalyst includes one or more of dibutyltin dilaurate (DBTDL), triethylenediamine (TEDA), and triethanolamine (TEA); And / or, the amount of the catalyst used is 0.1 to 1 mol% (molar percentage) of the polyol.

8. The method according to any one of claims 1-7, characterized in that: The injection flow rate of the polyurethane paint A is 20-40 ml / min; And / or, the injection flow rate of the polyurethane paint B is 40-88 ml / min; And / or, in the curing film-forming step, the curing temperature is 80–120°C; And / or, in the curing film-forming step, the curing time is 3 to 15 minutes.

9. A method for preparing an in-mold coated nonpolar material component, characterized in that, The method includes applying a hydrophobic polyurethane coating to the surface of a non-polar substrate as described in any one of claims 1-8.

10. An in-mold coated nonpolar material component prepared by the method of any one of claims 1-8.

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