Non-polar thermoplastic material with polar surface coating as well as preparation method and application of non-polar thermoplastic material

Abstract

The invention relates to a non-polar thermoplastic plate with a polar surface coating as well as a preparation method and application of the non-polar thermoplastic plate, and belongs to the technical field of automobile coatings. The problems that in the prior art, in the process of attaching a paint film to the surface of a non-polar thermoplastic plate, a base material is prone to thermal stress or deformation, the paint film is uneven in attachment and prone to falling off or peeling off, cost is high, process time is long, and industrialization is difficult to achieve are solved. According to the method, low-cost polyphenol and amine substances are used for spraying codeposition, and a particle coating with a certain thickness and roughness is formed on the surface of the non-polar thermoplastic plate by regulating and controlling the condition parameters of the spraying process, so that the adhesion capacity of the surface of a matrix is enhanced; the introduced active groups increase the surface polarity of the matrix and enhance the interface bonding between the matrix and the paint film; the particle coating is prepared at normal temperature, so that thermal stress or deformation caused by heating of a matrix is avoided; and by adopting the processes of adding a strong oxidant and spraying and codepositing, the modification time is greatly shortened, the working efficiency is improved, and the industrial production of the modified non-polar thermoplastic plate is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of automobile coatings, and in particular to a non-polar thermoplastic material with a polar surface coating, a preparation method and application thereof. Background Art

[0002] Non-polar thermoplastic sheets are widely favored by the industry for their economy and excellent processing performance. Due to their excellent mechanical properties such as high strength, hardness and toughness, they are ideal for producing impact-resistant and load-bearing automotive parts. However, their low surface energy and non-polar molecular chains have poor bonding with paint films, affecting the adhesion of paint film coatings on substrates.

[0003] In order to increase the surface energy of non-polar thermoplastic materials and improve their compatibility, wettability, and bonding properties with other materials (such as polar materials, resins, etc.), non-polar thermoplastic materials can be surface modified. At present, physical or chemical methods are mainly used to change the properties of the material surface to make it easier to combine with other materials, thereby improving the overall performance of the composite material. Physical methods mainly include mechanical treatment, flame treatment, and plasma treatment, but physical methods have the problems of limited modification effect, great impact on the material body, unstable modification effect, and high cost; chemical methods mainly include graft copolymerization, chemical oxidation, and surface coating, but during the graft copolymerization and chemical oxidation modification process, the non-polar thermoplastic matrix material undergoes a chemical reaction, resulting in changes in the internal structure of the material, thereby affecting the mechanical properties and thermal stability of the material.

[0004] Surface coating modification is to attach a layer of polar polymer or functional coating to the surface of the material to improve the surface properties of the material. This method is simple and easy to implement, and has little effect on the base material. However, in the prior art, the bonding force between the coating and the base material is not strong enough, and it is easy to fall off during use, resulting in the failure of the modification effect. The coating modification effect is poor, and the paint film is not firmly attached to the coating surface or the uniformity is poor. The coating preparation process requires high-temperature heating and drying, which can easily cause thermal stress or deformation of non-polar thermoplastic sheets. The preparation process of the sheet surface coating takes a long time, uses a large amount of chemicals, and is difficult to industrialize.

[0005] Therefore, in view of the problems existing in the prior art, there is an urgent need for a method that can truly improve the interfacial bonding strength between the paint film and the non-polar thermoplastic sheet and have little effect on the performance of the substrate, so as to promote technological progress and innovation in the automotive industry. Summary of the invention

[0006] In view of the above analysis, the embodiments of the present invention aim to provide a non-polar thermoplastic sheet with a polar surface coating, and a preparation method and application thereof, to solve at least one of the problems of the prior art when a paint film is attached to the surface of the non-polar thermoplastic plate, namely, thermal stress or deformation of the substrate, uneven adhesion of the paint film, easy shedding or peeling, high cost, long process time, and difficulty in industrialization.

[0007] In a first aspect, an embodiment of the present invention provides a non-polar thermoplastic material, wherein a polar coating is attached to the surface of the non-polar thermoplastic material, and the coating is a particle layer.

[0008] Furthermore, the particle size of the particles in the particle layer is 0.1-3 μm.

[0009] Furthermore, the material constituting the coating contains polar groups, and the polar groups are one or more of amino groups, phenolic hydroxyl groups, and quinone structures.

[0010] Furthermore, the material constituting the coating has a structure shown in formula (1):

[0011]

[0012] In a second aspect, an embodiment of the present invention provides a method for preparing a non-polar thermoplastic material, the method comprising: reacting polyphenols and amines on the surface of a non-polar thermoplastic substrate to be processed to obtain a non-polar thermoplastic material having a polar surface coating.

[0013] Furthermore, the polyphenol is a phenolic substance;

[0014] Furthermore, the amine is tetraethylenepentamine and / or triethylenetetramine.

[0015] Furthermore, the molar ratio of the phenolic substance to the amine is 3:1, 2:1, 1:1, 1:2, or 1:3.

[0016] Furthermore, the reaction is carried out in the presence of an oxidant, and the oxidant is at least one of Na IO4, KMnO4, (NH4)2S2O8, and H2CrO4.

[0017] Furthermore, the mass ratio of the polyamine to the oxidant is 1:1, 1:2, 1:3, 1:4, or 2:1.

[0018] Furthermore, the reaction is spraying rapid co-deposition.

[0019] Furthermore, the pH of the spraying co-deposition reaction solution is 7.5-8.5.

[0020] Furthermore, the reaction temperature is 15-35°C and the reaction time is 5-10 minutes.

[0021] In a third aspect, an embodiment of the present invention provides an application of a non-polar thermoplastic material in an automobile component, wherein the non-polar thermoplastic material is the non-polar thermoplastic material described in the first aspect or a non-polar thermoplastic material prepared by the method described in the second aspect.

[0022] Furthermore, a paint film is attached to the surface of the non-polar thermoplastic material.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] 1. The polar coating attached to the surface of the modified non-polar thermoplastic sheet of the present invention is a polyphenol-polyamine cross-linked polymer particle layer, which, on the one hand, increases the roughness of the surface of the non-polar thermoplastic substrate and enhances the adhesion ability of the substrate surface; on the other hand, the polar coating increases the polarity of the substrate surface, enhances the adhesion between the substrate and the paint film, further improves the interface bonding strength between the paint film and the substrate, and prevents the paint film from falling off or peeling off. The adhesion of the polyurethane resin paint film attached to the surface of the modified non-polar thermoplastic sheet of the present invention is level 0.

[0025] 2. The thickness and particle size of the polar microparticle coating attached to the surface of the non-polar thermoplastic sheet of the present invention will affect the surface roughness, uniformity and mechanical properties of the coating, thereby affecting the bonding strength of the paint film on the surface of the non-polar thermoplastic sheet modified by the coating, as well as the requirements for the mechanical properties of the non-polar thermoplastic sheet in practical applications. The particle size of the polar microparticles of the present invention is 0.1-3 μm, which not only ensures the roughness that improves the adhesion ability of the non-polar thermoplastic material, but also maintains the good mechanical properties of the non-polar thermoplastic material itself, without affecting the practical application.

[0026] 3. The polar groups of the microparticle coating attached to the surface of the non-polar thermoplastic sheet of the present invention play a bridging role between the sheet and other bonding materials; similar to polydopamine, the polyphenol-polyamine cross-linked polymer constituting the coating of the present invention has a cross-linked network structure, and the polymer molecular structure contains phenolic hydroxyl, carbonyl, and amine polar groups, and contains the structural unit shown in formula (1); the polar groups can form hydrogen bonds, covalent bonds and other interactions with the non-polar sheet substrate and the paint film material, respectively, thereby improving the interface bonding strength between the non-polar sheet substrate and the paint film, and preventing the substrate on the surface of the sheet substrate from falling off or peeling off.

[0027] 4. The catechol group in the dopamine monomer undergoes oxidative polymerization with the amine group to generate polydopamine with strong bonding properties. The present invention uses polyphenol substances with the same groups to react with polyamine substances to generate polyphenol-polyamine cross-linked polymers with the same strong bonding properties, which are firmly attached to the surface of non-polar thermoplastic sheets, improve the surface roughness and polarity of the sheets, and enhance the interfacial bonding strength between the non-polar sheets and other polymers or materials (such as paint films).

[0028] 5. The size of the obtained particles and the thickness of the particle coating can be controlled by adjusting the ratio and dosage of the polyphenols and polyamines and the type and dosage of the oxidant. The molar ratio of the polyphenols, the amines and the oxidant is 4:2:1. The strong oxidants (NaIO4, KMnO4, (NH4)2S2O8, H2CrO4) are used to accelerate the oxidation reaction of the catechol group and reduce the temperature requirement of the oxidation reaction, so that the reaction of the polyphenols and the polyamines can proceed smoothly at room temperature, which can avoid the problem of thermal stress or deformation of the plate substrate under high-temperature reaction conditions and shorten the coating generation time.

[0029] 6. The reaction between the polyphenols and the polyamines of the present invention adopts a spraying co-deposition process, and the acid-base conditions of the reaction are controlled by the configuration of the spraying solution. By controlling the concentration of the spraying solution and the spraying speed, the co-deposited solution can be quickly dried in a short time, reducing the requirements for drying temperature and time. On the other hand, it avoids high-temperature drying conditions that cause the board to generate thermal stress or deformation, shortens the modification time, improves work efficiency, and is conducive to the industrial production of modified non-polar thermoplastic boards.

[0030] 7. The non-polar thermoplastic sheet with a polar surface coating prepared by the method of the present invention does not involve the main material of the sheet in the chemical reaction, and the reaction conditions for generating the coating are mild, which does not change the structure of the main material, thereby avoiding the influence on the mechanical properties and thermal stability of the material. Compared with the coating modified by dopamine polymerization commonly used in the prior art, the amount of raw materials used and the cost are greatly reduced in the present invention.

[0031] 8. The method of the present invention for improving the interfacial bonding strength between a paint film and a non-polar thermoplastic substrate has broad application prospects. The application of non-polar thermoplastic materials with polar surface coatings to automobile parts is of great significance to the automobile industry.

[0032] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The particles are deposited on the surface of a modified non-polar thermoplastic substrate.

[0034] Figure 2 Specific steps of the surface coating preparation method for improving the interface bonding strength;

[0035] Figure 3 Adhesion test of samples for implementation of regulations.

[0036] In the figure:

[0037] 1. Non-polar thermoplastic substrate; 2. Deposited particles. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0039] In order to improve the compatibility, wettability, and bonding properties of non-polar thermoplastic materials with other materials (such as polar materials, resins, etc.), the non-polar thermoplastic materials can be surface modified. At present, physical or chemical methods are mainly used to change the properties of the material surface to make it easier to combine with other materials, thereby improving the overall performance of the composite material. Physical methods mainly include mechanical treatment, flame treatment, and plasma treatment, but physical methods have the problems of limited modification effect, great impact on the material body, unstable modification effect, and high cost; chemical methods mainly include graft copolymerization, chemical oxidation, and surface coating, but during the graft copolymerization and chemical oxidation modification process, the non-polar thermoplastic matrix material undergoes a chemical reaction, resulting in changes in the internal structure of the material, thereby affecting the mechanical properties and thermal stability of the material.

[0040] Surface coating modification is to apply a layer of polar polymer or functional coating on the surface of the material to improve the surface properties of the material. This method is simple and easy to implement and has little effect on the base material. However, the bonding force between the coating and the base material in the prior art is not strong enough, and it is easy to fall off during use, resulting in the failure of the modification effect. The uniformity of the paint film adhering to the coating surface is poor. High-temperature heating and drying are required during the coating preparation process, which can easily cause thermal stress or deformation of non-polar thermoplastic materials.

[0041] Therefore, the present invention provides a modified non-polar thermoplastic sheet, wherein a polar coating is attached to the surface of the non-polar thermoplastic sheet, wherein the coating is a layer of polyphenol-polyamine cross-linked polymer particles, such as Figure 1 shown.

[0042] The polar coating attached to the surface of the modified non-polar thermoplastic sheet of the present invention is a polyphenol-polyamine cross-linked polymer particle layer, which increases the roughness of the surface of the non-polar thermoplastic substrate and enhances the adhesion ability of the substrate surface; on the other hand, the polar coating increases the polarity of the substrate surface, enhances the adhesion between the substrate and the paint film, further improves the interface bonding strength between the paint film and the substrate, and prevents the paint film from falling off or peeling off. The adhesion of the polyurethane resin paint film attached to the surface of the modified non-polar thermoplastic sheet of the present invention is level 0. The molecular structure of the polyphenol-polyamine cross-linked polymer contains functional groups such as phenolic hydroxyl groups and amine groups, which can form hydrogen bonds, covalent bonds and other interactions with other molecules or material surfaces, so that it can firmly adhere to the material surface.

[0043] The thickness and particle size of the polar microparticle coating attached to the surface of the non-polar thermoplastic sheet of the present invention will affect the surface roughness, uniformity and mechanical properties of the coating, thereby affecting the bonding strength of the paint film on the surface of the non-polar thermoplastic sheet modified by the coating, as well as the requirements for the mechanical properties of the non-polar thermoplastic sheet in practical applications.

[0044] The particle size of the polar coating particles of the present invention is 0.1-3 μm, preferably 0.3-0.5 μm. If the particle size is too large, large particles may form larger protrusions or depressions when stacked, affecting the surface flatness of the non-polar thermoplastic material; large particles are prone to form larger gaps or weak connection points in the coating, and these positions are more likely to peel off or fall off when subjected to external forces, thereby reducing the overall adhesion of the coating; if the particle size is too small, although the contact area between the coating and the substrate surface can be increased and the adhesion of the coating can be improved, the roughness will be reduced to a certain extent, affecting the adhesion performance of the non-polar thermoplastic material surface.

[0045] The polar groups of the microparticle coating attached to the surface of the non-polar thermoplastic plate of the present invention not only make the coating firmly attached to the surface of the plate, play a modification role, but also can be combined with the interface between the paint films to enhance the adhesion of the paint films on the surface of the substrate and prevent them from falling off or peeling off. The polyphenol-polyamine polymer structure constituting the coating of the present invention contains phenolic hydroxyl, carbonyl, and amine polar groups, and contains structural units represented by formula (1) or / and formula (2).

[0046] The polar groups of the microparticle coating attached to the surface of the non-polar thermoplastic sheet of the present invention play a bridging role between the sheet and other bonding materials; similar to polydopamine, the molecular structure of the polyphenol-polyamine polymer constituting the coating of the present invention contains phenolic hydroxyl, carbonyl and amine polar groups, and contains structural units represented by formula (1) or / and formula (2); the polar groups can form hydrogen bonds, covalent bonds and other interactions with the non-polar sheet substrate and the paint film material, respectively, thereby improving the interface bonding strength between the non-polar sheet substrate and the paint film, and preventing the substrate on the surface of the sheet substrate from falling off or peeling off.

[0047] The polyphenolic substance used to prepare the polyphenol-polyamine cross-linked polymer of the present invention is at least one of catechol and dopamine, preferably catechol.

[0048] The polyamine substance used to prepare the polyphenol-polyamine polymer of the present invention is at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine, preferably tetraethylenepentamine.

[0049] The polyphenol-polyamine polymer of the present invention contains structural units represented by formula (1) or / and formula (2):

[0050]

[0051] The present invention discloses a method for preparing a modified non-polar thermoplastic sheet, the method comprising: reacting polyphenols and polyamines on the surface of a non-polar thermoplastic substrate to be processed to obtain a modified non-polar thermoplastic material. Figure 2 shown.

[0052] In order to ensure that the coating in the prepared modified non-polar thermoplastic sheet has strong bonding force not only with the surface of the base material, but also with the paint film, and to truly serve as a bridge between the two without affecting the application performance of the base material, the present invention needs to limit the raw materials for generating the coating.

[0053] The catechol group in the dopamine monomer undergoes oxidative polymerization with the amine group to generate polydopamine with strong bonding properties. The present invention uses polyphenol substances with the same groups to react with polyamine substances to generate polyphenol-polyamine polymers with the same strong bonding properties, which are firmly attached to the surface of non-polar thermoplastic plates, improve the surface roughness and polarity of the plates, and enhance the interface bonding strength between the non-polar plates and other polymers or materials (such as paint films).

[0054] The preparation method of the present invention controls the thickness of the prepared modified coating by regulating the amount of raw materials added.

[0055] In order to enhance the surface adhesion and polarity of the non-polar thermoplastic sheet substrate and improve the interface bonding ability between it and the paint film, the molar ratio of the polyphenol substance to the polyamine substance of the present invention is 1:1, 2:1, 1:1, 1:2, 1:3.

[0056] Polyphenols are oxidized under alkaline conditions to form quinone structures, which react with polyamines to form a cross-linked network through Michael addition or Schiff base reaction, forming a particle coating on the surface of the non-polar thermoplastic material substrate to be processed. When phenols and polyamines undergo co-deposition reaction, if the proportion of phenols is too high, the amino content in the deposited layer will be low, the benzene density will be high, resulting in a high chain stiffness and cross-linking density of the polymer, which is conducive to the polymer to form particles rather than films through π-π stacking and aggregation, which is not conducive to the density and continuity of the coating, resulting in uneven modification, affecting the uniformity and firmness of subsequent paint film adhesion; if the proportion of amines is too high, the relative proportion of phenols in the polymerization product is too low, which is not conducive to the deposition reaction and the adhesion of the coating on the surface of the non-polar thermoplastic sheet substrate. However, an appropriate amount of excess amines can react with the hydroxyl groups in the paint film, thereby improving the interface bonding performance.

[0057] In order to promote the reaction between polyphenols and amines, reduce the temperature requirements of the reaction, and shorten the reaction time, the present invention limits the type and amount of the oxidant.

[0058] The oxidant used in the present invention is a strong oxidant, which is at least one of NaIO4, KMnO4, (NH4)2S2O8, and H2CrO4. The strong oxidant used in the present invention accelerates the oxidation reaction of the catechol group, reduces the temperature requirement of the oxidation reaction, and allows the reaction of polyphenols and polyamines to proceed smoothly at room temperature, thereby avoiding the problem of thermal stress or deformation of the plate substrate under high temperature reaction conditions and shortening the coating generation time.

[0059] The molar ratio of the amine substance to the oxidant of the present invention is 1:1, 1:2, 1:3, 1:4, 2:1. If an excessive amount of oxidant is added during the co-precipitation reaction of the phenol substance and the amine substance, the deposition process of the phenol substance and the amine substance on the carbon fiber surface will be inhibited; if the amount of the oxidant added is too small, the deposition speed is too slow, resulting in an increase in the operation time.

[0060] like Figure 2 As shown, the present invention provides a specific step of a surface coating preparation method for improving interface bonding strength. The reaction between the polyphenolic substance and the polyamine substance of the present invention adopts a spraying co-deposition process, and the acid-base conditions of the reaction are controlled by the configuration of the spraying solution. By controlling the concentration of the spraying solution, the spraying pressure and the speed, the co-deposited solution can be quickly dried in a short time, reducing the requirements for temperature and time for drying. On the other hand, it avoids the high temperature drying condition causing the plate to generate thermal stress or deformation, shortens the modification time, improves the work efficiency, and is conducive to the industrial production of modified non-polar thermoplastic plates.

[0061] Furthermore, the concentration of the phenolic substance in the spraying co-deposition reaction solution of the present invention is 2 mg / mL. If the concentration of the reaction solution is too high, the raw material reaction will be insufficient, resulting in defects in the obtained modified coating, affecting the modification effect; if the solubility of the reaction solution is too low, the reaction efficiency will be reduced, the reaction of generating the polymer has not yet been carried out, and the reaction solution will flow under the influence of the outside world, resulting in coating defects and unevenness, and the subsequent drying will be more difficult.

[0062] Furthermore, the pH of the spray co-deposition reaction solution of the present invention is 7.5-8.5, which is more conducive to the reaction. This is because the alkaline environment will promote the deprotonation of the phenolic hydroxyl group in the catechol group to form phenol anions. The electron cloud density of the benzene ring in this anionic state increases, making it easier to lose electrons and be oxidized.

[0063] The present invention realizes the control of the pH value of the reaction solution by means of a solvent, and the requirements for the solvent used are that it does not participate in the reaction between the polyphenol and the polyamine and can adjust the pH value of the reaction solution; the present invention preferably uses a mixed solution of Tris-HCl buffer solution and anhydrous ethanol, and ethanol is volatile, and after the reaction, it will accelerate the evaporation of the solvent and the drying of the coating.

[0064] Before the co-deposition of the coating, the present invention uses acetone or / and anhydrous ethanol to soak-ultrasonicate or / and wipe the non-polar thermoplastic plate to be processed to clean the surface of the non-polar thermoplastic plate, remove various pollutants and organic residues on the surface, including grease, oxides, dust, etc., to ensure the surface cleanliness, which is beneficial to improving the modification effect of the coating on the plate substrate.

[0065] After the co-deposition of the coating, the present invention uses anhydrous ethanol and deionized water to post-treat the coating deposited on the surface of the substrate to remove unreacted raw materials.

[0066] The non-polar thermoplastic sheet material with a polar surface coating prepared by the method of the present invention does not participate in the chemical reaction of the sheet material itself, and the reaction conditions for generating the coating are mild, which will not change the structure of the material body, thereby avoiding the influence on the mechanical properties, thermal stability and other aspects of the material; compared with the coating modified by dopamine polymerization commonly used in the prior art, the raw material usage and cost of the present invention are greatly reduced.

[0067] The invention discloses application of a non-polar thermoplastic sheet in automobile parts. The non-polar thermoplastic sheet is the modified non-polar thermoplastic sheet.

[0068] Furthermore, when the modified non-polar thermoplastic sheet is applied to automobile parts (such as automobile engine hood), a paint film needs to be attached to its surface to protect automobile parts, beautify the appearance, identify the type of vehicle, and improve comfort and sealing, etc. The adhesion of the paint film on the surface of the sheet will affect the appearance quality of the paint film layer. If the adhesion of the paint film is insufficient, the paint film will have defects such as cracks and cracks, as well as impurities, bubbles, etc. during the coating or drying process, resulting in unevenness on the substrate surface and reduced glossiness of the paint film; during use, it is easy to fall off or bubbles appear when subjected to external forces or environmental changes, which will destroy the integrity of the appearance, shorten the service life of the sheet, and increase energy consumption.

[0069] The coating material in the modified non-polar thermoplastic sheet of the present invention is a polyphenol-polyamine cross-linked polymer, which has strong adhesion and can firmly adhere to the surface of the non-polar thermoplastic sheet, improve the surface roughness and polarity of the sheet, and improve the interface bonding force between the non-polar sheet and other polymers or materials (such as paint film). The modified non-polar thermoplastic sheet of the present invention and the preparation method thereof have broad application prospects. The application of non-polar thermoplastic materials with polar surface coatings to automobile parts is of great significance to the automobile industry.

[0070] Example 1

[0071] (1) Use anhydrous ethanol and acetone to spray and wipe the surface of the PP sheet substrate to remove pollutants and organic residues on the substrate surface;

[0072] (2) At a temperature of 25°C, 10 mL and 5 mL of a mixed solution of Tris-HCl-anhydrous ethanol containing phenol and amines and a 2 mg / mL Tris-HCl-anhydrous ethanol solution of an oxidant were sprayed on the substrate surface (10 cm*10 cm) in sequence for co-deposition for 5 min; wherein the mass ratio of Tris-HCl to anhydrous ethanol was 1:1-1:5, the solubility of phenol and amine in the mixed solution was 2 mg / mL and 2 mg / mL, respectively, and the concentration of the oxidant was 1 mg / mL; the spraying speed was 1-4 cm2 / s.

[0073] (3) using anhydrous ethanol and deionized water to rinse the surface coating of the co-deposited substrate to remove unreacted raw materials, thereby obtaining a PP sheet 1 having a coating on the surface;

[0074] (4) Through microscopic morphology SEM measurement, it was found that the particle size of the coating particles on the surface of plate 1 was 0.3-0.5 μm.

[0075] Example 2

[0076] The same method as in Example 1 was adopted, except that the Tris-HCl-anhydrous ethanol solution of the oxidant sprayed in step (2) was 6 mg / mL and the co-deposition time was 5 min, to obtain a PP plate 3 with a coating on the surface; microscopic morphology SEM measurement showed that the particle size of the coating particles on the surface of the plate 3 was 1-2 μm.

[0077] Example 3

[0078] The same method as in Example 1 is adopted, except that the spraying speed in step (2) is 3 cm2 / s and the co-deposition time is 5 min; a PP plate 4 with a coating on the surface is obtained; and the particle size of the coating particles on the surface of the plate 4 is 1-3 μm as measured by SEM.

[0079] Comparative Example 1

[0080] Different from Example 1, this comparative example uses different coatings to modify the plate to obtain Plate 5.

[0081] Comparative Example 2

[0082] The PP plate is polished to obtain plate 6.

[0083] Comparative Example 3

[0084] The PP sheet was subjected to fire treatment to obtain sheet 7.

[0085] Application Examples

[0086] The paint film adhesion was carried out using Examples 1-3 and Comparative Examples 1-3, and the paint film adhesion was measured. Figure 3 shown.

[0087] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A modified non-polar thermoplastic sheet, characterized in that: A polar coating is attached to the surface of the board, and the coating is a polyphenol-polyamine cross-linked polymer particle layer.

2. The material according to claim 1, characterized in that The particle size of the particles in the particle layer is 0.1-3 μm.

3. The material according to claim 1, characterized in that The polyphenol is at least one of catechol and methylphenol.

4. The material according to claim 1, characterized in that The polyamine is at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine.

5. The material according to claim 1, characterized in that The polyphenol-polyamine polymer contains structural units represented by formula (1) or / and formula (2):

6. The material according to claim 1, characterized in that The non-polar thermoplastic sheet is a PP sheet and / or a PE sheet.

7. A method for preparing a modified non-polar thermoplastic sheet, characterized in that: The method comprises: making polyphenol and polyamine react on the surface of a non-polar thermoplastic sheet to be processed to obtain a modified non-polar thermoplastic sheet.

8. The method according to claim 7, characterized in that The polyphenol is at least one of catechol and methylphenol.

9. The method according to claim 7, characterized in that: The polyamine is at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine.

10. The method according to claim 7, characterized in that The molar ratio of the polyphenol to the polyamine is 3:1, 2:1, 1:1, 1:2, or 1:

3.

11. The method according to claim 7, characterized in that The reaction is carried out in the presence of an oxidant, which is at least one of NaIO4, KMnO4, (NH4)2S2O8, and H2CrO4.

12. The method according to claim 11, characterized in that The mass ratio of the polyamine to the oxidant is 1:1, 1:2, 1:3, 1:4, or 2:

1.

13. The method according to claim 7, characterized in that The reaction is spray-fast co-deposition.

14. The method according to claim 13, characterized in that The concentration of the spraying co-deposition reaction solution is 2 mg / mL, and the pH is 7.5-8.

5.

15. The method according to claim 13, characterized in that Spraying speed 1-4cm 2 / s.

16. The method according to claim 7, characterized in that The non-polar thermoplastic sheet is PP or / and PE sheet.

17. The method according to any one of claims 7 to 16, characterized in that: The reaction temperature is 15-35°C and the reaction time is 5-10 minutes.

18. Application of a non-polar thermoplastic material in automobile parts, characterized in that: The non-polar thermoplastic material is the non-polar thermoplastic material according to any one of claims 1 to 6 or the non-polar thermoplastic material prepared by the method according to any one of claims 7 to 17.

19. The use according to claim 18, characterized in that A paint film is attached to the surface of the non-polar thermoplastic material.

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