A modified chlorinated polypropylene resin, its preparation method and use in the preparation of a bumper hydrobasecoat

Abstract

This invention discloses a modified chlorinated polypropylene resin, its preparation method, and its application in the preparation of water-based primers for bumpers, belonging to the field of primer technology. The water-based primer for bumpers provided by this invention has high hardness, a non-sticky surface, can be activated at low temperatures, and requires no flame treatment. The bumper primer resin prepared by this invention comprises three components: the first component is a carbon dioxide-based polyol, whose carbonate and ether linkage structures improve the hydrolysis resistance and damp heat resistance of the water-based primer; the second component is sodium styrene sulfonate and the rigid benzene ring structure of styrene, which improves the hardness of the water-based primer resin and addresses the stickiness of the paint film surface; the third component, sodium styrene sulfonate groups, ensures the water dispersibility of the primer resin.

Description

Technical Field

[0001] This invention belongs to the field of primer technology, specifically relating to a modified chlorinated polypropylene resin, its preparation method, and its application in the preparation of water-based primers for bumpers. Background Technology

[0002] Polypropylene (PP) materials, with their advantages of light weight, good toughness, low price, and excellent chemical resistance, have been widely used in the automotive bumper field. However, as a non-polar material with low surface energy, PP is difficult to wet. Therefore, before applying paint, bumper materials need to undergo flame treatment, followed by a 15-20% chlorinated polypropylene primer solution to enhance surface adhesion and interlayer adhesion with other coatings. In recent years, with the introduction of national environmental protection policies, water-based primers for bumpers have become a development trend in this field. However, water-based chlorinated polypropylene resin, as the main resin in water-based primers, requires graft modification during preparation, resulting in a sticky condition at room temperature and a particularly low film hardness, failing to meet automotive-grade primer requirements. Furthermore, compared to solvent-based primers, water-based primers require high-temperature activation above 90°C, which is not only energy-intensive but also poses a risk of bumper deformation. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] To address the existing problems in this field, the present invention aims to provide a high-hardness, non-sticky, low-temperature-activated, and flame-free water-based primer for bumpers, as well as its preparation method. The bumper primer resin provided by the present invention comprises three components: the first component is a carbon dioxide-based polyol, whose carbonate and ether linkage structures improve the hydrolysis resistance and damp heat resistance of the water-based primer; the second component, sodium styrene sulfonate and the rigid benzene ring structure of styrene, improves the hardness of the water-based primer resin and addresses the stickiness of the paint film surface; the third component, sodium styrene sulfonate groups, ensures the water dispersibility of the primer resin.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the object of this invention is to overcome the shortcomings of the prior art and provide a modified chlorinated polypropylene resin. The main chain structure of the modified chlorinated polypropylene resin is chlorinated polypropylene, with rigid styrene units, sodium styrene sulfonate units, and carbon dioxide-based polyol structural units grafted onto its side chains.

[0007] The styrene unit and the sodium styrene sulfonate unit are grafted into the main chain structure by free radical polymerization, and the carbon dioxide-based polyol unit is incorporated into the main chain structure by polyurethane reaction.

[0008] The mass ratio of the chlorinated polypropylene to styrene, sodium styrene sulfonate, and carbon dioxide-based polyol is 160–350: 10.5–14.8: 12.5–20.8: 420–510;

[0009] The chlorinated polypropylene has a weight-average molecular weight (Mw) of 100,000 to 250,000, and the mass content of chlorine is 10% to 30%.

[0010] The modified chlorinated polypropylene resin also has a structure as shown in general formula (Ⅰ):

[0011]

[0012] Where R is selected from One of them.

[0013] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing modified chlorinated polypropylene resin.

[0014] To solve the above-mentioned technical problems, the present invention provides the following technical solutions, including:

[0015] Mix 160–350 parts of chlorinated polypropylene and 200–400 parts of toluene, and heat until completely dissolved to obtain a chlorinated polypropylene solution.

[0016] 12.5–20.8 parts sodium styrene sulfonate, 10.5–14.8 parts styrene, 20.6–30.5 parts intermediate, and 180–300 parts toluene are mixed until completely dissolved to obtain the grafting solution.

[0017] 2.1–3.6 parts of initiator and 20–45 parts of toluene are mixed until completely dissolved to obtain an initiator solution;

[0018] Under a nitrogen atmosphere, the chlorinated polypropylene solution and the grafting solution were mixed and heated to 60-80°C. Then, the initiator solution was added dropwise and the reaction was continued for 1-3 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0019] 50.8–81.6 parts of grafted chlorinated polypropylene intermediate, 18.5–23.7 parts of diisocyanate, 420–510 parts of carbon dioxide-based polyol, and 3.5–4.2 parts of trimethylolpropane were mixed evenly and reacted at 70–85°C for 1–2 hours. Then, 0.3–0.8 parts of antioxidant, 2.4–4.1 parts of butanediol, and 0.3–0.8 parts of catalyst were added. The mixture was then melt-extruded using a twin-screw extruder and pelletized underwater to obtain modified chlorinated polypropylene resin.

[0020] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the preparation method of the intermediate includes:

[0021] 100-110 parts of maleic anhydride and 140-150 parts of 1-naphthylamine were mixed and then added to xylene, 0.1-0.5 parts of hydroquinone, and 0.5-1.0 parts of p-toluenesulfonic acid. The mixture was reacted at 120-150℃ for 4-8 hours. Then, 30% sodium carbonate solution was added, and the mixture was allowed to stand for separation. The xylene layer was taken, washed, dried, and the xylene was removed under reduced pressure to obtain the intermediate precursor.

[0022] The intermediate precursor was dissolved in isopropanol, and sodium borohydride was added in five batches. After all the sodium borohydride was added, the temperature was raised to 55–75 °C and reacted for 3–5 h. Then, the temperature was lowered to room temperature, deionized water was added, and the mixture was stirred for 15 min. The pH was adjusted to neutral, and the isopropanol and deionized water were evaporated under reduced pressure. Deionized water and methylcyclohexane were added, and the mixture was stirred at room temperature for 20 min. The mixture was allowed to stand and separate into layers, retaining the methylcyclohexane organic layer. The mixture was washed, dried, and the solvent was removed to obtain the intermediate.

[0023] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the preparation method of the intermediate includes:

[0024] 107.9 parts maleic anhydride and 145.8 parts 1-naphthylamine were mixed and then added to xylene, 0.35 parts hydroquinone and 0.8 parts p-toluenesulfonic acid. The mixture was reacted at 130°C for 6 hours. Then, 30% sodium carbonate solution was added and the mixture was allowed to stand for separation. The xylene layer was taken, washed and dried, and the xylene was removed under reduced pressure to obtain the intermediate precursor.

[0025] The intermediate precursor was dissolved in isopropanol, and sodium borohydride was added in five batches. After all the sodium borohydride was added, the temperature was raised to 65°C and reacted for 4.5 h. Then, the temperature was lowered to room temperature, deionized water was added, and the mixture was stirred for 15 min. The pH was adjusted to neutral, and the isopropanol and deionized water were evaporated under reduced pressure. Deionized water and methylcyclohexane were added, and the mixture was stirred at room temperature for 20 min. The mixture was allowed to stand and separate into layers, retaining the methylcyclohexane organic layer. The mixture was washed, dried, and the solvent was removed to obtain the intermediate.

[0026] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the dropping rate of the initiator is 1.5 to 4.0 ml / min.

[0027] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the chlorinated polypropylene has a weight-average molecular weight Mw of 100,000 to 250,000 and a chlorine content of 10% to 30%.

[0028] The initiator includes one or more of benzoyl peroxide, dicumyl peroxide, dilauryl peroxide, 1,1-di(tert-butylperoxy)3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peracetate, tert-amyl peroxy-2-ethylhexanoate, and dilauryl peroxide.

[0029] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the diisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and phenylmethylene diisocyanate.

[0030] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the number average molecular weight of the carbon dioxide-based polyol is 3300-6000, and the unit content is 30.6-54.8%.

[0031] The antioxidants include one or more of hindered phenolic and phosphite antioxidants, including one or more of antioxidants 1010, antioxidant 1076, antioxidant 1098, antioxidant 1790, and antioxidant 168.

[0032] The catalyst is an organometallic catalyst, including one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate.

[0033] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the twin-screw melt extrusion process includes the following steps: the process temperature of each section of the screw is 120-130℃, 145-155℃, 160-170℃, 170-180℃, 170-180℃, 160-170℃, 160-170℃, 155-165℃, and 155-165℃; the die temperature is 150-160℃; the rotation speed is 200-300 rpm; and the total time is 2-4 min.

[0034] In a preferred embodiment of the preparation method of the modified chlorinated polypropylene resin of the present invention, the twin-screw melt extrusion process includes the following steps: the process temperature of each section of the screw is 130℃, 150℃, 165℃, 175℃, 175℃, 175℃, 165℃, 165℃, 160℃, and 160℃; the die temperature is 155℃; the rotation speed is 275 rpm; and the total residence time is 3 min.

[0035] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of modified chlorinated polypropylene resin in the preparation of water-based primers for bumpers.

[0036] To solve the above-mentioned technical problems, the present invention provides the following technical solution, wherein the water-based primer for the bumper includes one of water-based primer paint and water-based primer emulsion.

[0037] Another objective of this invention is to overcome the shortcomings of the prior art and provide an aqueous primer emulsion, the preparation method of which includes,

[0038] Mix 15-25 parts of modified chlorinated polypropylene resin with 55-65 parts of deionized water and 0.1-0.5 parts of sodium dodecyl sulfate evenly, and emulsify at 80-90°C with stirring; after emulsification, cool to room temperature to obtain a water-based primer resin emulsion for bumpers.

[0039] The stirring speed is 1100-1300 rpm and the stirring time is 20-40 min.

[0040] As a preferred embodiment of the method for preparing the aqueous primer emulsion of the present invention, it includes:

[0041] Mix 20 parts of water-based primer resin with 60 parts of deionized water and 0.3 parts of sodium dodecyl sulfate evenly, and emulsify at 85°C with stirring; after emulsification, cool to room temperature to obtain the water-based primer resin emulsion for the bumper.

[0042] The stirring speed is 1100-1300 rpm and the stirring time is 30 min.

[0043] Another objective of this invention is to overcome the shortcomings of the prior art and provide a water-based primer, the preparation method of which includes,

[0044] Mix 260-400 parts of titanium dioxide, 5-12 parts of carbon black, 2-8 parts of water-based wetting and dispersing agent, and 4-7 parts of water-based defoamer, and sand mill for 2-4 hours. When the fineness reaches 8μm, add 1680-2850 parts of water-based primer resin, 160-220 parts of film-forming aid, 1.5-4 parts of water-based wetting and leveling agent, 3-5 parts of silica, and 28-45 parts of water-based curing agent, and disperse at high speed to obtain the water-based primer for the bumper.

[0045] The stirring rate for high-speed dispersion is 300-500 rpm, and the stirring time is 5-8 min.

[0046] As a preferred embodiment of the water-based primer of the present invention, the film-forming aid is one or more of the following: dodecyl alcohol ester, diethylene glycol butyl ether, dipropylene glycol monobutyl ether, dipropylene glycol methyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol monobutyl ether.

[0047] The aqueous wetting and dispersing agent is one or more of BYK-180, BYK-190, BYK-191, BYK-192, BYK-194, BYK-199 and BYK-2015.

[0048] The water-based defoamer is one or more of BYK-022, BYK-024, BYK-028, BYK-093, BYK-1786, TEGO FOAMEX822, TEGO AIREX 901W, and TEGO AIREX 902W.

[0049] The water-based wetting and leveling agent is one or more of BYK-346, BYK-381, BYK-3456, BYK-3760, or DAPROW-77.

[0050] The preferred water-based curing agent is one or more of Bayhydur 3100, Bayhydur 2451, Bayhydur XP2655, or Desmodur N 3800.

[0051] The carbon black is selected from Cabot carbon black, BP2000, REGAL 250R, and REGAL 400R.

[0052] Silica is preferably one or more of Evonik's R972, R974, R816, R805 and R812.

[0053] Beneficial effects of this invention:

[0054] This invention provides a flame-free, high-hardness waterborne primer resin for bumpers, with a hardness of 1H to 2H, far exceeding that of waterborne chloropropylene emulsion systems. Furthermore, it eliminates the need for flame treatment, making application more convenient.

[0055] The bumper primer resin prepared by this invention comprises three components: the first component is a carbon dioxide-based polyol, the carbonate and ether bond structure in which can improve the hydrolysis resistance and damp heat resistance of the water-based primer; the second component is sodium styrene sulfonate and the rigid benzene ring structure of styrene in the structural formula, which improves the hardness of the water-based primer resin and solves the problem of stickiness on the paint film surface; the third component, sodium styrene sulfonate group, ensures the water dispersibility of the primer resin. Attached Figure Description

[0056] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0057] Figure 1 The ATR spectrum of the modified chlorinated polypropylene resin prepared in Example 1 of this invention is shown.

[0058] Figure 2 This is a SEM image of the modified chlorinated polypropylene resin prepared in Example 1 of the present invention.

[0059] Figure 3 The ATR spectrum of the modified chlorinated polypropylene resin prepared in Example 2 of this invention is shown.

[0060] Figure 4 This is a SEM image of the modified chlorinated polypropylene resin prepared in Example 2 of the present invention.

[0061] Figure 5 This is a SEM image of the resin prepared in Comparative Example 1 of this invention. Detailed Implementation

[0062] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0063] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0064] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0065] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0066] Carbon dioxide-based polyols were prepared according to the method reported in invention patent 201110231493.6.

[0067] Preparation of the intermediate: 107.9 g of maleic anhydride and 145.8 g of 1-naphthylamine were added to a reaction flask, along with xylene, 0.35 g of hydroquinone, and 0.8 g of p-toluenesulfonic acid. The temperature was controlled at 130 °C, and the reaction was carried out for 6 h. Then, 450 ml of 30% sodium carbonate solution was added, and the mixture was allowed to stand for separation. The xylene layer was removed. The xylene layer was then washed three times with 300 ml of deionized water. The xylene organic layer was dried with anhydrous magnesium sulfate. After drying, the xylene was removed under reduced pressure to obtain the intermediate precursor. The intermediate precursor was dissolved in 450 ml of isopropanol, and sodium borohydride was added in five batches at room temperature. After all the sodium borohydride was added, the temperature was raised to 65 °C, and the reaction was carried out for 4.5 h. The temperature was then lowered to room temperature, and 600 ml of deionized water was added. The mixture was stirred for 15 min, and the pH was adjusted to neutral with 30% sulfuric acid. The isopropanol and deionized water were evaporated under reduced pressure. Add 500 ml of deionized water and 700 ml of methylcyclohexane, stir at room temperature for 20 min, allow to stand and separate into layers, remove the aqueous layer, retain the methylcyclohexane organic layer, wash the organic layer 5 times with 650 ml of deionized water, dry the obtained organic layer with anhydrous magnesium sulfate, remove the solvent after drying, and obtain the intermediate.

[0068] The materials obtained in the embodiments of the present invention were subjected to performance testing according to the following method:

[0069] The surface of the composite polypropylene material of the bumper was wiped clean with a lint-free cloth. Then, at a humidity of 65% and a temperature of 25°C, a water-based primer was sprayed onto the surface using an air spraying method. After activation in a 60°C oven for 5 minutes, the dry film thickness was 10-12 micrometers. After seven days, the relevant performance tests of the paint film were carried out.

[0070] 1. Particle size test: The water-based primer resin was diluted in a Malvern cuvette (DTS0012) and then tested using a Brookhaven ZetaPlus analyzer dynamic light dispersion (DLS) instrument at a test temperature of 25℃.

[0071] 2. ATR (Total Reflection Infrared) Performance Test: The prepared resin was placed in a polytetrafluoroethylene dish and left at room temperature for 48 hours. After drying, it was vacuum dried at 40℃ for 72 hours. The ATR performance was then tested using a Bruker INVENIO-R Fourier Transform Infrared Spectrometer (Germany). The parameters were diamond reflective crystal and the scanning range was 4000–400 cm⁻¹. -1 Resolution: 4cm -1 Number of scans: 128.

[0072] 3. SEM (Scanning Electron Microscopy) test: The resin sample is placed in liquid nitrogen, removed, fractured, and the cross-section is sputter-coated with gold. The SEM performance test is performed on an XL-30 field emission scanning electron microscope.

[0073] 4. Emulsion stability test: Centrifuge the water-based primer resin at 5000 rpm for 30 minutes and observe whether there is any precipitation at the bottom.

[0074] 5. Adhesion (cross-cut test): The test shall be conducted in accordance with the method of GB / T 13217.7-2009.

[0075] 6. Hardness (pencil hardness) test: The test shall be conducted in accordance with the method of GB / T 6739-2022.

[0076] 7. Steam injection and climate alternation shall be tested in accordance with the TL211 standard method.

[0077] Example 1

[0078] This embodiment provides a method for preparing modified chlorinated polypropylene resin, specifically as follows:

[0079] 1) Preparation of chlorinated polypropylene solution: Add 160 parts of chlorinated polypropylene (Mw = 100,000, chlorine content = 10%) to 200 ml of water. 份 In toluene, the temperature is raised to 65°C to completely dissolve chlorinated polypropylene, yielding a chlorinated polypropylene solution.

[0080] 2) Preparation of grafting solution: Add 12.5 parts sodium styrene sulfonate, 10.5 parts styrene, and 20.6 parts intermediate to 180 parts toluene, stir at room temperature for 30 minutes to obtain grafting solution.

[0081] 3) Preparation of initiator solution: Dissolve 2.1 parts of benzoyl peroxide in 20 parts of toluene until completely dissolved to obtain an initiator solution with a mass fraction of 10.5%.

[0082] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 60℃. The initiator solution was added dropwise at a rate of 1.5 ml / min. After all the solution was added, the reaction was continued for 3 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0083] 5) 50.8 parts of grafted chlorinated polypropylene intermediate, 18.5 parts of toluene diisocyanate, 420 parts of carbon dioxide-based polyol (Example 15 in Invention Patent 201110231493.6, Mn = 3300 Da, Cu% = 30.6%) and 3.5 parts of trimethylolpropane were mixed and reacted at 70°C for 2 hours. Then, the material was added to a twin-screw extruder, along with 0.3 parts of antioxidant 1010, 2.4 parts of butanediol, and 0.5 parts of dibutyltin dilaurate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C, the die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3 minutes. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0084] The main chain structure of the modified chlorinated polypropylene resin in this embodiment is chlorinated polypropylene, with rigid styrene units, sodium styrene sulfonate units, and carbon dioxide-based polyol structural units grafted onto its side chains. The styrene units and sodium styrene sulfonate units are grafted into the main chain structure through free radical polymerization, and the carbon dioxide-based polyol units are incorporated into the main chain structure through polyurethane reaction.

[0085] Figure 1 The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment: 553.5 cm⁻¹ -1 702.1cm -1 831.2cm -1 946.9cm -1 1110.9cm -1 1247.8cm -1 1377.1cm -1 1452.3cm -1 1512.1cm -1 1612.4cm -1 1728.1cm -1 2873.7cm -1 2921.9cm -1 2952.8cm -1 3205.5cm -1 3352.1cm -1 3442.7cm -1 2400cm in the spectrum -1~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0086] The positions of the peaks in the infrared spectrum indicate that the target resin product was successfully prepared.

[0087] Example 2

[0088] 1) Add 350 parts of chlorinated polypropylene (Mw is 250,000, chlorine mass content is 30%) to 400 parts of toluene, heat to 90℃ to completely dissolve the chlorinated polypropylene, forming a chlorinated polypropylene solution;

[0089] 2) Add 20.8 parts sodium styrene sulfonate, 14.8 parts styrene, and 30.5 parts intermediate to 300 parts toluene, stir at room temperature for 30 minutes to obtain grafting solution;

[0090] 3) Dissolve 3.6 parts of dicumyl peroxide in 45 parts of toluene until completely dissolved to obtain an initiator solution;

[0091] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 80℃. The initiator solution was added dropwise at a rate of 4 ml / min. After all the solution was added, the reaction was continued for 1 hour. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0092] 5) 81.6 parts of grafted chlorinated polypropylene intermediate, 23.7 parts of diphenylmethane diisocyanate, 510 parts of carbon dioxide-based polyol (Example 8 in Invention Patent 201110231493.6, Mn = 6000 Da, Cu% = 34.3%) and 4.2 parts of trimethylolpropane were mixed and reacted at 85°C for 1 hour. Then, the material was added to a twin-screw extruder, along with 0.8 parts of antioxidant 1076, 4.1 parts of butanediol, and 0.5 parts of stannous octoate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C, the die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3 minutes. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0093] Figure 3 The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment is shown at 559.3 cm⁻¹. -1 707.8cm -1 827.4cm -1 947.1cm -1 1136.0cm -1 1245.9cm -1 1374.6cm -1 1453.8cm -11514.0cm -1 1606.4cm -1 1728.5cm -1 2871.8cm -1 2922.3cm -1 2950.9cm -1 3188.8cm -1 3441.5cm -1 2400cm in the spectrum -1 ~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0094] The positions of the peaks in the infrared spectrum indicate that the target resin product was successfully prepared.

[0095] Example 3

[0096] 1) Add 240 parts of chlorinated polypropylene (Mw is 150,000, chlorine content is 15%) to 300 parts of toluene, heat to 70°C to completely dissolve the chlorinated polypropylene, and form a chlorinated polypropylene solution.

[0097] 2) Add 14.8 parts sodium styrene sulfonate, 11.6 parts styrene, and 24.5 parts intermediate to 210 g of toluene and stir at room temperature for 30 min to obtain grafting solution;

[0098] 3) Dissolve 2.6g of 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane in 30g of toluene until completely dissolved to obtain an initiator solution;

[0099] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 70°C. The initiator solution was added dropwise at a rate of 2.5 ml / min. After all the solution was added, the reaction was continued for 2 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0100] 5) 61.2g of grafted chlorinated polypropylene intermediate, 21.5g of isophorone diisocyanate, 480g of carbon dioxide-based polyol (Example 12 in Invention Patent 201110231493.6, Mn = 5800 Da, Cu% = 35.2%) and 3.7g of trimethylolpropane were mixed and reacted at 75°C for 1.5h. Then, the material was added to a twin-screw extruder, along with 0.5g of antioxidant 1098, 2.9g of butanediol, and 0.5g of dibutyltin diacetate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C. The die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3min. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0101] The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment is 554.2 cm⁻¹. -1 703.5cm -1 824.9cm -1 948.6cm -1 1122.7cm -1 1240.8cm -1 1370.6cm -1 1455.3cm -1 1512.8cm -1 1610.3cm -1 1730.2cm -1 2873.5cm -1 2920.2cm -1 2953.4cm -1 3186.2cm -1 3440.9cm -1 Of which 2400cm -1 ~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0102] Example 4

[0103] 1) Add 310g of chlorinated polypropylene (Mw = 200,000, chlorine content 22%) to 350g of toluene, heat to 80℃ to completely dissolve the chlorinated polypropylene, forming a chlorinated polypropylene solution;

[0104] 2) Add 18.5g sodium styrene sulfonate, 13.2g styrene, and 28.5g intermediate to 280g toluene and stir at room temperature for 30min to obtain grafting solution;

[0105] 3) Dissolve 2.8g of dilauryl peroxide in 35g of toluene until completely dissolved to obtain an initiator solution;

[0106] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 75°C. The initiator solution was added dropwise at a rate of 3.5 ml / min. After all the solution was added, the reaction was continued for 2 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0107] 5) 66.5g of grafted chlorinated polypropylene intermediate, 19.6g of dicyclohexylmethane diisocyanate, 500g of carbon dioxide-based polyol (Example 17 in Invention Patent 201110231493.6, Mn = 3500 Da, Cu% = 54.8%) and 3.8g of trimethylolpropane were mixed and reacted at 75°C for 1.5h. Then, the material was added to a twin-screw extruder, along with 0.4g of antioxidant 1790, 3.6g of butanediol, and 0.8g of dibutyltin dilaurate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C, the die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3min. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0108] The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment is 561.3 cm⁻¹. -1 703.9cm -1 825.2cm -1 951.8cm -1 1132.5cm -1 1247.2cm -1 1371.6cm -1 1458.2cm -1 1510.6cm -1 1602.9cm -1 1730.2cm -1 2868.5cm -1 2918.4cm -1 2948.1cm -1 3180.7cm -1 3445.9cm -1 Of which 2400cm -1 ~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0109] Example 5

[0110] 1) Add 320g of chlorinated polypropylene (Mw=150,000, chlorine content of 17%) to 400g of toluene, heat to 85℃ to completely dissolve the chlorinated polypropylene, forming a chlorinated polypropylene solution;

[0111] 2) Add 17.6g sodium styrene sulfonate, 13.5g styrene, and 26.5g intermediate to 260 parts of toluene and stir at room temperature for 30 minutes to obtain the grafting solution;

[0112] 3) Dissolve 3.4 parts of tert-amyl peroxide in 30 parts of toluene until completely dissolved to obtain an initiator solution;

[0113] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 70°C. The initiator solution was added dropwise at a rate of 3 ml / min. After all the solution was added, the reaction was continued for 2 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0114] 5) 71.5 parts of grafted chlorinated polypropylene intermediate, 22.5 parts of diisocyanate, 480 parts of carbon dioxide-based polyol (Invention Patent 201110231493.6, Example 16, Mn = 3300 Da, Cu% = 39.3%) and 3.9 parts of trimethylolpropane were mixed and reacted at 80°C for 1.5 h. Then, the material was added to a twin-screw extruder, along with 0.7 parts of antioxidant 168, 3.7 parts of butanediol, and 0.3 parts of stannous octoate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C, the die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3 min. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0115] The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment is 561.8 cm⁻¹. -1 710.2cm -1 825.6cm -1 943.4cm -1 1140.5cm -1 1241.8cm -1 1370.3cm -1 1447.8cm -1 1516.2cm -1 1603.6cm -1 1724.3cm -1 2869.2cm -1 2920.4cm -1 2948.3cm -1 3181.6cm -1 3439.7cm -1 Of which 2400cm -1 ~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0116] Example 6

[0117] 1) Add 270 parts of chlorinated polypropylene (Mw = 130,000, chlorine content 24%) to 270 parts of toluene, heat to 75°C to completely dissolve the chlorinated polypropylene, forming a chlorinated polypropylene solution;

[0118] 2) Add 19.5 parts sodium styrene sulfonate, 13.5 parts styrene, and 24.6 parts intermediate to 260 parts toluene and stir at room temperature for 30 minutes to obtain the grafting solution;

[0119] 3) Dissolve 2.8 parts of dicumyl peroxide in 30 parts of toluene until completely dissolved to obtain an initiator solution;

[0120] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 70°C. The initiator solution was added dropwise at a rate of 2 ml / min. After all the solution was added, the reaction was continued for 2 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate.

[0121] 5) 71.5 parts of grafted chlorinated polypropylene intermediate, 22.5 parts of phthalimide diisocyanate, 475 parts of carbon dioxide-based polyol (Invention Patent 201110231493.6, Example 8, Mn = 6000 Da, Cu% = 34.3%) and 3.7 parts of trimethylolpropane were mixed and reacted at 80°C for 1.5 h. Then, the material was added to a twin-screw extruder, along with 0.7 parts of antioxidant 1098, 3.7 parts of butanediol, and 0.8 parts of dibutyltin dilaurate. The screw process temperature was 130°C, 150°C, 165°C, 175°C, 175°C, 165°C, 165°C, 160°C, 160°C, the die temperature was 155°C, the rotation speed was 275 rpm, and the total residence time was 3 min. Finally, underwater pelletizing was performed to obtain modified chlorinated polypropylene resin.

[0122] The ATR spectrum of the modified chlorinated polypropylene resin prepared in this embodiment is 562.4 cm⁻¹. -1 701.7cm -1 825.2cm -1 945.9cm -1 1130.7cm -1 1246.4cm -1 1371.8cm -1 1451.4cm -1 1516.8cm -1 1604.2cm -1 1725.9cm -1 2864.8cm -1 2918.4cm -1 2947.5cm -1 3184.2cm-1 3445.1cm -1 Of which 2400cm -1 ~1900cm -1 These are mixed peaks of diamond and atmospheric carbon dioxide.

[0123] Comparative Example 1

[0124] This comparative example provides a method for preparing a waterborne primer resin for bumpers using a chlorinated polypropylene emulsion system, specifically as follows:

[0125] 1) Add 160 parts of chlorinated polypropylene (Mw is 100,000, chlorine mass content is 10%) to 30 parts of toluene and 350 parts of acetone, heat to 65℃ and stir evenly to obtain chlorinated polypropylene solution;

[0126] 2) Add 12.5 parts maleic anhydride, 10.5 parts butyl acrylate, and 20.6 parts acrylic acid to 180 parts of 50 parts acetone, stir at room temperature for 30 minutes to obtain the grafting solution;

[0127] 3) Dissolve 2.1 parts of benzoyl peroxide in 20 parts of toluene until completely dissolved to obtain an initiator solution;

[0128] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 60°C. The initiator solution was added dropwise at a rate of 1.5 ml / min. After all the solution was added, the reaction was continued for 3 hours. The temperature was then lowered to 30°C. 18 parts of triethylamine and 310 parts of deionized water were added, and acetone was removed under reduced pressure to obtain the aqueous chlorinated polypropylene emulsion of this comparative example.

[0129] Depend on Figure 2 , 4 Comparing Examples 1 and 2, the SEM images clearly show a filamentous structure in the cross-sectional structure of the resin, indicating that the resin has excellent toughness and is a tough material, thus ensuring the excellent adhesion of the obtained resin. However, Comparative Example 1 (…) Figure 5 The SEM image of the material does not show any filamentous structure, indicating that the material has poor toughness, is brittle, and has poor adhesion.

[0130] Comparative Example 2

[0131] This comparative example provides a method for preparing a waterborne primer resin for bumpers using a chlorinated polypropylene emulsion system, specifically as follows:

[0132] 1) Add 160 parts of chlorinated polypropylene (Mw is 100,000, chlorine mass content is 10%) to 30 parts of toluene and 350 parts of acetone, heat to 65℃ and stir evenly to obtain chlorinated polypropylene solution;

[0133] 2) Add 12.5 parts maleic anhydride, 10.5 parts styrene, and 20.6 parts acrylic acid to 180 parts of 50 parts acetone, stir at room temperature for 30 minutes to obtain the grafting solution;

[0134] 3) Dissolve 2.1 parts of benzoyl peroxide in 20 parts of toluene until completely dissolved to obtain an initiator solution;

[0135] 4) Under nitrogen protection, the chlorinated polypropylene solution and the grafting solution were mixed and the reaction temperature was raised to 60°C. The initiator solution was added dropwise at a rate of 1.5 ml / min. After all the solution was added, the reaction was continued for 3 hours. The temperature was then lowered to 30°C. 18 parts of triethylamine and 310 parts of deionized water were added, and acetone was removed under reduced pressure to obtain the aqueous chlorinated polypropylene emulsion of this comparative example.

[0136] Example 7

[0137] This embodiment provides a method for preparing an aqueous primer emulsion, specifically as follows:

[0138] 20 parts of water-based primer resin (modified chlorinated polypropylene resin prepared in Example 1) were mixed with 60 parts of deionized water and 0.3 parts of sodium dodecyl sulfate. The mixture was stirred at 1200 rpm for 30 minutes at 85°C to emulsify it. After emulsification, the mixture was cooled to room temperature and filtered through an 80-mesh filter to obtain the water-based primer emulsion for the bumper.

[0139] Example 8

[0140] This embodiment provides a method for preparing a water-based primer for bumpers, specifically as follows:

[0141] Prepare the water-based primer for the bumper according to the formula in Table 1 using the following steps.

[0142] 1) Add titanium dioxide, carbon black, water-based wetting and dispersing agent, and water-based defoamer to a sand mill jar for sand milling for 3 hours. When the fineness reaches 8μm, introduce it into a high-speed disperser.

[0143] 2) Add the water-based primer resin (modified chlorinated polypropylene resin) / water-based chlorinated polypropylene emulsion, film-forming aid, water-based wetting and leveling agent, silica and water-based curing agent to the high-speed disperser respectively. Stir at 400 rpm and mix at room temperature for 6 min to obtain the water-based primer paint for bumpers prepared from the water-based primer resin (modified chlorinated polypropylene resin) / water-based chlorinated polypropylene emulsion of different examples / comparative examples.

[0144] Table 1

[0145]

[0146]

[0147] The performance of the above-mentioned water-based primer was tested, and the results are shown in Table 2.

[0148] Table 2

[0149]

[0150] In summary, it can be seen that the water-based primer for bumpers provided by this invention has high hardness, a non-sticky surface, can be activated at low temperatures, and requires no flame treatment. The bumper primer resin prepared by this invention comprises three components: the first component is a carbon dioxide-based polyol, the carbonate and ether linkages in this structure can improve the hydrolysis resistance and damp heat resistance of the water-based primer; the second component is sodium styrene sulfonate and the rigid benzene ring structure of styrene in the structural formula, which improves the hardness of the water-based primer resin and solves the problem of stickiness on the paint film surface; the third component, sodium styrene sulfonate groups, ensures the water dispersibility of the primer resin.

[0151] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A modified chlorinated polypropylene resin, characterized in that: a. The main chain structure of the modified chlorinated polypropylene resin is chlorinated polypropylene, with rigid styrene units, sodium styrene sulfonate units, and carbon dioxide-based polyol structural units grafted onto its side chains. b. The styrene unit and the sodium styrene sulfonate unit are grafted into the main chain structure by free radical polymerization, and the carbon dioxide-based polyol unit is incorporated into the main chain structure by polyurethane reaction; c. The mass ratio of the chlorinated polypropylene to styrene, sodium styrene sulfonate, and carbon dioxide-based polyol is 160–350: 10.5–14.8: 12.5–20.8: 420–510; d. The chlorinated polypropylene has a weight-average molecular weight (Mw) of 100,000 to 250,000, wherein the mass content of chlorine is 10% to 30%.

2. The method for preparing a modified chlorinated polypropylene resin according to claim 1, characterized by: include, Mix 160–350 parts of chlorinated polypropylene and 200–400 parts of toluene, and heat until completely dissolved to obtain a chlorinated polypropylene solution. 12.5–20.8 parts sodium styrene sulfonate, 10.5–14.8 parts styrene, 20.6–30.5 parts intermediate, and 180–300 parts toluene are mixed until completely dissolved to obtain the grafting solution. 2.1–3.6 parts of initiator and 20–45 parts of toluene are mixed until completely dissolved to obtain an initiator solution; Under a nitrogen atmosphere, the chlorinated polypropylene solution and the grafting solution were mixed and heated to 60-80°C. Then, the initiator solution was added dropwise and the reaction was continued for 1-3 hours. The solvent was removed under reduced pressure to obtain the grafted chlorinated polypropylene intermediate. 50.8–81.6 parts of grafted chlorinated polypropylene intermediate, 18.5–23.7 parts of diisocyanate, 420–510 parts of carbon dioxide-based polyol, and 3.5–4.2 parts of trimethylolpropane were mixed evenly and reacted at 70–85°C for 1–2 hours. Then, 0.3–0.8 parts of antioxidant, 2.4–4.1 parts of butanediol, and 0.3–0.8 parts of catalyst were added. The mixture was then melt-extruded using a twin-screw extruder and pelletized underwater to obtain modified chlorinated polypropylene resin.

3. The method of producing a modified chlorinated polypropylene resin according to claim 2, characterized by: The method for preparing the intermediate. include, 100-110 parts of maleic anhydride and 140-150 parts of 1-naphthylamine were mixed and then added to xylene, 0.1-0.5 parts of hydroquinone, and 0.5-1.0 parts of p-toluenesulfonic acid. The mixture was reacted at 120-150℃ for 4-8 hours. Then, 30% sodium carbonate solution was added, and the mixture was allowed to stand for separation. The xylene layer was taken, washed, dried, and the xylene was removed under reduced pressure to obtain the intermediate precursor. The intermediate precursor was dissolved in isopropanol, and sodium borohydride was added in five batches. After all the sodium borohydride was added, the temperature was raised to 55–75 °C and reacted for 3–5 h. Then, the temperature was lowered to room temperature, deionized water was added, and the mixture was stirred for 15 min. The pH was adjusted to neutral, and the isopropanol and deionized water were evaporated under reduced pressure. Deionized water and methylcyclohexane were added, and the mixture was stirred at room temperature for 15–20 min. The mixture was allowed to stand and separate into layers, retaining the methylcyclohexane organic layer. The mixture was washed, dried, and the solvent was removed to obtain the intermediate.

4. The method of preparing a modified chlorinated polypropylene resin according to claim 2, characterized by: The initiator has a dropping rate of 1.5–4.0 ml / min.

5. The method of preparing a modified chlorinated polypropylene resin according to claim 2, wherein the chlorinated polypropylene resin is chlorinated polypropylene resin (A). The initiator includes one or more of benzoyl peroxide, dicumyl peroxide, dilauroyl peroxide, 1,1-di(tert-butylperoxy)3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peracetate, tert-amyl peroxy-2-ethylhexanoate, and dilauroyl peroxide. The diisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and phenylmethylene diisocyanate.

6. The method for preparing the modified chlorinated polypropylene resin according to claim 2, characterized in that: The carbon dioxide-based polyol has a number average molecular weight of 3300-6000 and a unit content of 30.6-54.8%. The antioxidants include one or more of hindered phenolic and phosphite antioxidants, including one or more of antioxidants 1010, antioxidant 1076, antioxidant 1098, antioxidant 1790, and antioxidant 168. The catalyst is an organometallic catalyst, including one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate.

7. The method for preparing the modified chlorinated polypropylene resin according to claim 2, characterized in that: The twin-screw melt extrusion process includes the following steps: the process temperature of each screw section is 120–130℃, 145–155℃, 160–170℃, 170–180℃, 170–180℃, 160–170℃, 160–170℃, 155–165℃, and 155–165℃; the die temperature is 150–160℃; the rotation speed is 200–300 rpm; and the total time is 2–4 min.

8. The application of the modified chlorinated polypropylene resin as described in claim 1 in the preparation of water-based primer for bumpers, characterized in that: The water-based primer for the bumper includes one of water-based primer paint and water-based primer emulsion.

9. An aqueous basecoat paint, characterized in that: Its preparation methods include, Mix 260-400 parts of titanium dioxide, 5-12 parts of carbon black, 2-8 parts of water-based wetting and dispersing agent, and 4-7 parts of water-based defoamer, and mill evenly for 2-4 hours. When the fineness reaches 8 μm, add 1680-2850 parts of the modified chlorinated polypropylene resin as described in claim 1, 160-220 parts of film-forming aid, 1.5-4 parts of water-based wetting and leveling agent, 3-5 parts of silica, and 28-45 parts of water-based curing agent. Stir at high speed of 300-500 rpm for 5-8 minutes to obtain the water-based primer for the bumper.

10. An aqueous primer emulsion, characterized in that: Its preparation methods include, Mix 15-25 parts of the modified chlorinated polypropylene resin according to claim 1 with 55-65 parts of deionized water and 0.1-0.5 parts of sodium dodecyl sulfate evenly, and emulsify at 80-90°C under stirring; after emulsification, cool to room temperature to obtain the water-based primer emulsion for the bumper. The stirring speed is 1100-1300 rpm and the stirring time is 20-40 min.

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