A modified polyolefin resin composition, a method for preparing the same, and a hot melt marking paint

Abstract

The application discloses a modified polyolefin resin composition, mainly comprising the following components in parts by weight: 90-102 parts of polar monomer grafted polyethylene and polar monomer grafted polyethylene wax, wherein the polyethylene segment is 67-90 parts, and the polyethylene wax segment is 9-30 parts; the grafting rate of the polar monomer in the modified polyolefin resin composition ranges from 0.8 to 2.0 wt%; and the polyethylene in the polar monomer grafted polyethylene is at least one selected from LDPE and LLDPE. The modified polyolefin resin composition is suitable for an adhesion promoting resin of hot melt marking paint.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a modified polyolefin resin composition and its preparation method, and a hot-melt marking paint. Background Technology

[0002] Road marking paint, also known as road line paint, is mainly divided into two categories: hot-melt and solvent-based. Hot-melt marking paint currently dominates the market in my country, accounting for about 90% of the total usage, due to its advantages such as low cost, fast drying, thick film, simple application, and environmental friendliness with low odor.

[0003] Currently, commercially available hot-melt road marking paint is mainly composed of C5 petroleum resin compounded with pigments, fillers, and PE wax and other additives. This system has relatively weak polarity and generally poor adhesion to the ground. Therefore, in actual construction, a primer is first applied to the ground before the hot-melt road marking paint is applied to improve its adhesion. However, due to long-term outdoor exposure, hot-melt road markings are subjected to sun exposure, water immersion, and tire pressure. After 6-9 months of actual use, hot-melt road markings are prone to peeling off, resulting in blurred markings and creating road traffic hazards.

[0004] Patent CN 114621622 B discloses a hot-melt road marking modification material. This material comprises polyvinyl chloride, polyamide resin, ABS resin, polytetrafluoroethylene, polyetheretherketone, ethylene-vinyl acetate copolymer, styrene-butadiene-styrene front copolymer, silane coupling agent, sodium fatty alcohol polyoxyethylene ether sulfate, and methylsilicic acid. When this hot-melt road marking modification material is added to a hot-melt road marking modified coating, it can significantly improve the adhesion between the marking coating and glass microspheres, thereby improving the durability of the road marking's retroreflective coefficient. However, this patent primarily focuses on improving the adhesion between the hot-melt road marking coating and glass microspheres, with limited impact on the adhesion between the hot-melt road marking coating and the primer. Summary of the Invention

[0005] The purpose of this invention is to provide a modified polyolefin resin composition that can improve the adhesion between hot-melt road marking paint and primer.

[0006] This invention is achieved through the following technical solution: A modified polyolefin resin composition, comprising the following components in parts by weight: The total amount of polar monomer grafted polyethylene and polar monomer grafted polyethylene wax is 90-102 parts, of which polyethylene segments are 67-90 parts and polyethylene wax segments are 9-30 parts. In the modified polyolefin resin composition, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%. The polyethylene in the polar monomer grafted polyethylene is selected from at least one of LDPE and LLDPE.

[0007] Preferably, in the modified polyolefin resin composition, the grafting rate of the polar monomer ranges from 1.2 to 1.7 wt%. The grafting rate of the polar monomer in the modified polyolefin resin composition can be 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, etc.

[0008] In the modified polyolefin resin composition of the present invention, the polar monomer grafted polyethylene and the polar monomer grafted polyethylene wax account for not less than 97 wt% of the total weight.

[0009] The test method for the polar monomer content in modified polyolefin resin compositions is acid-base titration.

[0010] The specific procedure is as follows: Dissolve the grafted material in xylene under reflux. After cooling, add a certain amount of 0.05 mol / L potassium hydroxide-ethanol solution, and then reflux for 8 hours. Using 0.1% phenolphthalein solution as an indicator, titrate with 0.05 mol / L HCl-isopropanol solution while hot to the endpoint. The grafting rate G is calculated using the following formula: G = (N1 × Vl - N2 × V2) × M ÷ w ÷ 10 In the formula: N1: KOH—equivalent concentration of ethanol solution, N; V1: Volume of KOH ethanol solution, ml; N2: Equivalent concentration of HCl-isopropanol solution, N; V2: Volume of HCl-isopropanol solution, ml; M: Equivalent mass of maleic anhydride, g; w: Mass of the dried sample after extraction, in g.

[0011] The modified polyolefin resin composition of the present invention has a melt index of 50-500 g / 10 min at 190°C and 2.16 kg.

[0012] The polar monomer is selected from at least one of maleic anhydride, methyl methacrylate, methacrylic acid, acrylic acid, acrylamide, and glycidyl methacrylate.

[0013] Preferably, the polar monomer is selected from maleic anhydride.

[0014] Depending on the actual situation, it may be optional to add 0-2 parts of additives, which are selected from at least one of anti-crosslinking agents, antioxidants, and lubricants.

[0015] The modified polyolefin resin composition of the present invention can be prepared by a one-pot method, or by first melt-blending polar monomer-grafted polyethylene with polar monomer-grafted polyethylene wax. The one-pot method is preferred.

[0016] Specifically, the one-pot preparation method includes the following steps: according to the grafting rate of polar monomers and the weight content of polyethylene and polyethylene wax in the modified polyolefin resin composition, the polar monomers, initiators, and anti-crosslinking agents are mixed and dispersed in a solvent. The weight of the solvent is 0.5-2 times the total weight of the polar monomers, initiators, and anti-crosslinking agents. Then, it is mixed evenly with polyethylene and polyethylene wax, and extruded and granulated through a twin-screw extruder (screw temperature is 150-180℃, length-to-diameter ratio is greater than or equal to 40:1) to obtain the modified polyolefin resin composition. The solvent is selected from acetone, methanol, ethyl acetate, etc., and most of the solvent will evaporate during the preparation process.

[0017] Preferably, the initiator is selected from at least one of dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, and cumyl peroxide, and the amount of initiator used is 0.1-0.5 wt% of the amount of polyethylene and polyethylene wax added; and / or The anti-crosslinking agent is selected from at least one of autolactam, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and thioester, and the amount of anti-crosslinking agent used is 0.5-2 times the amount of initiator added; and / or The LDPE and LLDPE that achieve the purpose of this invention have a melt index of 50-100 g / 10 min at 190°C and 2.16 kg. And / or The polyethylene wax that can achieve the purpose of this invention has a weight-average molecular weight of 500-2000. The weight-average molecular weight is tested using GPC.

[0018] Another method for preparing the modified polyolefin resin composition of the present invention is to mix and extrude polar monomer grafted polyethylene and polar monomer grafted polyethylene wax by a twin-screw extruder at an extrusion temperature of 160-200°C and a screw speed of 300-400 rpm.

[0019] Preferably, in the polar monomer-grafted polyethylene, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%, more preferably from 1.2 to 1.7 wt%. Preferably, in the polar monomer-grafted polyethylene wax, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%, more preferably from 1.2 to 1.7 wt%.

[0020] In the above modified polyolefin resin composition, the grafting rates of polar monomers grafted onto polyethylene and polar monomers grafted onto polyethylene wax can be the same or different. The grafting rates of polar monomers grafted onto polyethylene and polar monomers grafted onto polyethylene wax can be 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, etc.

[0021] Polar monomer grafted polyethylene (or polar monomer grafted polyethylene wax) can be commercially available or made in-house. The in-house method is as follows: mix polar monomer, initiator and polyethylene (or polyethylene wax) evenly, and extrude and granulate through a twin-screw extruder (screw temperature 150-180℃, length-to-diameter ratio greater than or equal to 40:1) to obtain polar monomer grafted polyethylene (or polar monomer grafted polyethylene wax).

[0022] A hot-melt road marking paint, comprising the following components by weight: 15-25 parts of petroleum resin; 3-7 parts of polyethylene wax; 3-7 parts titanium dioxide; 50-90 parts of calcium carbonate powder; The modified polyolefin resin composition of the present invention comprises 3-7 parts.

[0023] The petroleum resin is selected from C5 petroleum resin, C9 petroleum resin, hydrogenated C5 petroleum resin, hydrogenated C9 petroleum resin, C5 / C9 mixed petroleum resin, etc.

[0024] In the hot-melt road marking paint of the present invention, the petroleum resin content by weight can be 15 parts, 17 parts, 19 parts, 21 parts, 23 parts, 25 parts, etc.; the polyethylene wax content can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, etc.; the titanium dioxide content can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, etc.; the calcium carbonate powder can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, etc.; and the modified polyolefin resin composition content of the present invention can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, etc.

[0025] Those skilled in the art may also choose to add other additives to the hot-melt marking paint according to actual needs. The other additives may be 0-2 parts of UV stabilizer, etc.

[0026] The present invention has the following beneficial effects: This invention obtains a high-flow, high-polarity polyolefin-grafted polar monomer resin by grafting polar monomers onto polyethylene and polyethylene wax with polar monomers in a specific ratio and grafting rate. Due to its good flowability, this resin can be well dispersed in hot-melt road marking paint, and at the same time, it can have a synergistic effect with petroleum resin, significantly improving the adhesion between hot-melt road marking paint and base coat, thus achieving the effect of an adhesion promoter. Detailed Implementation

[0027] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0028] The raw materials used in this invention are sourced from the following sources: LLDPE-1: ExxonMobil 6201, melt index 50 g / 10min, 190℃, 2.16kg.

[0029] LLDPE-2: DOW LLDPE DNDA-1082, melt index is 160g / 10min, 190℃, 2.16kg.

[0030] LDPE: Sinopec LDPE 868-000, melt index is 50 g / 10min, 190℃, 2.16kg.

[0031] HDPE: HDPE 8920, melt index is 20g / 10min, 190℃, 2.16kg.

[0032] Polyethylene wax-1: weight average molecular weight 800, R-110, Yiteng Chemical.

[0033] Polyethylene wax-2: weight average molecular weight 1500, DP0020F, Qingdao East.

[0034] Maleic anhydride: Yunsheng Chemical (Shandong) Co., Ltd.

[0035] Acrylamide: Maclean's.

[0036] Glycidyl methacrylate (GMA): Jinan Huijinchuan Chemical Co., Ltd.

[0037] Acetone: Qiming Chemical.

[0038] Dicumyl peroxide: Shandong Haijing New Materials Co., Ltd.

[0039] Dimethylformamide: Zibo Zida Chemical Trading Co., Ltd.

[0040] Polar monomer grafted polyethylene-1: maleic anhydride grafting rate 0.83wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-2: maleic anhydride grafting rate 1.27wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-3: maleic anhydride grafting rate 1.66wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-4: maleic anhydride grafting rate 1.92wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-5: maleic anhydride grafting rate 0.36wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-6: maleic anhydride grafting rate 2.38wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene-7: GMA grafting rate 1.61wt%, main chain is LLDPE-2, self-made; Polar monomer grafted polyethylene wax-1: maleic anhydride grafting rate 0.88wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-2: maleic anhydride grafting rate 1.20wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-3: maleic anhydride grafting rate 1.64wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-4: maleic anhydride grafting rate 1.95wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-5: maleic anhydride grafting rate 0.31wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-6: maleic anhydride grafting rate 2.40 wt%, main chain is polyethylene wax-1, self-made; Polar monomer grafted polyethylene wax-7: GMA grafting rate 1.65wt%, main chain is polyethylene wax-2, self-made; The preparation method of the above polar monomer-grafted polyethylene or polar monomer-grafted polyethylene wax is as follows: Polar monomers, initiators (diisopropylbenzene peroxide), and polyethylene (or polyethylene wax) are mixed evenly and then extruded and granulated using a twin-screw extruder at a screw temperature of 150-180℃ and an aspect ratio of 44:1 to obtain polar monomer-grafted polyethylene (or polar monomer-grafted polyethylene wax). The grafting rate of the polar monomer is then determined by acid-base titration.

[0041] C5 petroleum resin: Jinda Chemical.

[0042] Titanium dioxide: Lomon Billions.

[0043] Calcium carbonate powder: Guangxi Hezhou Junfei Powder Co., Ltd.

[0044] Preparation method of modified polyolefin resin composition A in the examples and comparative examples: Polar monomers, initiators (dicumyl peroxide), and anti-crosslinking agents (dimethylformamide) are mixed and dispersed in a solvent (acetone). The weight of the solvent is 1.0 times the total weight of the polar monomers, initiators, and anti-crosslinking agents. The amount of initiator is 0.2 wt% of the amount of polyethylene and polyethylene wax added, and the amount of anti-crosslinking agent is 1 times the amount of initiator added. Then, it is mixed evenly with polyethylene and polyethylene wax, and extruded and granulated through a twin-screw extruder. The screw temperature is 150-180℃ and the length-to-diameter ratio is 44:1 to obtain the modified polyolefin resin composition.

[0045] Preparation method of modified polyolefin resin composition B in the examples and comparative examples: polar monomer grafted polyethylene, polar monomer grafted polyethylene wax and additives are melt-extruded through a twin-screw extruder, wherein the barrel temperature is 160-200℃, and the screw speed is 300-400 rpm to obtain the modified polyolefin resin composition.

[0046] Preparation method of hot melt road marking paint: Mix 20 parts of C5 petroleum resin, 5 parts of polyethylene wax, 4 parts of titanium dioxide, 70 parts of calcium carbonate powder, and modified polyolefin resin composition A (or B) evenly and grind to obtain hot melt road marking paint.

[0047] Test methods: (1) Softening point of hot melt road marking paint: Refer to GB / T16311-2009 Road Traffic Marking Quality Requirements and Testing Methods; (2) Compressive strength of hot-melt road marking paint: Refer to GB / T16311-2009 Road Traffic Marking Quality Requirements and Testing Methods; (3) Peel strength of hot melt marking paint: refer to GB / T2792-1998 Test method for 180° peel strength of pressure sensitive tape.

[0048] (4) Melt index: The test standard is ISO 1133-1:2022, and the conditions are 190℃ and 2.16kg.

[0049] (5) Polar monomer content test: The grafted material was dissolved in xylene by heating and reflux. After cooling, a certain amount of 0.05 mol / L potassium hydroxide-ethanol solution was added, and the mixture was heated and refluxed for another 8 hours. Using 0.1% phenolphthalein solution as an indicator, the solution was titrated with 0.05 mol / L HCl-isopropanol solution while hot to the endpoint. The grafting rate G was calculated using the following formula: G = (N1 × Vl - N2 × V2) × M ÷ w ÷ 10 In the formula: N1: KOH—equivalent concentration of ethanol solution, N; V1: Volume of KOH ethanol solution, ml; N2: Equivalent concentration of HCl-isopropanol solution, N; V2: Volume of HCl-isopropanol solution, ml; M: Equivalent mass of maleic anhydride, g; w: Mass of the dried sample after extraction, in g.

[0050] Table 1: Addition amount (parts by weight) of each component in modified polyolefin resin compositions A1-A6 and test results LLDPE-1 67.5 LLDPE-2 77 77 77 77 LDPE 85.5 Polyethylene wax-1 28.5 17 17 17 17 Polyethylene wax-2 9.5 Maleic anhydride 3.5 2.0 3.0 4.0 5.0 GMA 5.0 polar monomer grafting rate (wt%) 1.47 1.83 0.83 1.13 1.65 1.91 Melt index g / 10min 271 55 112 155 190 233 Table 2: Addition amount (parts by weight) of each component in modified polyolefin resin compositions A7-A12 and test results LLDPE-2 77 77 77 57 91 HDPE 77 Polyethylene wax-1 17 17 17 17 37 3 Maleic anhydride 4.0 1.0 7.0 4.0 4.0 Acrylamide 4.0 polar monomer grafting rate (wt%) 1.59 1.56 0.46 2.81 1.61 1.57 Melt index g / 10min 91 110 56 254 240 35 Table 3: Addition amount (parts by weight) of each component in modified polyolefin resin compositions B1-B7 and test results The designation of polar monomer grafted polyethylene -1 -2 -3 -4 -7 -1 -2 Content of polar monomer grafted polyethylene 77 77 77 77 77 90 69.5 Polar monomer grafted polyethylene wax grade -1 -2 -3 -4 -7 -4 -3 Content of polar monomer grafted polyethylene wax 17 17 17 17 17 9.5 30 polar monomer grafting rate (wt%) 0.85 1.24 1.65 1.94 1.62 0.93 1.38 Melt index g / 10min 106 139 163 196 184 95 130 Table 4: Addition amount (parts by weight) of each component in modified polyolefin resin compositions B8-B13 and test results The designation of polar monomer grafted polyethylene -5 -6 -1 -1 -1 / Content of polar monomer grafted polyethylene 69.5 79 60 99.5 95.5 / Polar monomer grafted polyethylene wax grade -6 -5 -1 / -1 -1 Content of polar monomer grafted polyethylene wax 30 20 39.5 / 4 99.5 polar monomer grafting rate (wt%) 0.97 1.96 0.86 0.83 0.85 0.88 Melt index g / 10min 298 281 179 30 51 370 Preparation method of hot melt road marking paint: Mix 20 parts of C5 petroleum resin, 5 parts of polyethylene wax, 4 parts of titanium dioxide, 70 parts of calcium carbonate powder, and modified polyolefin resin composition A (or B) evenly and grind to obtain hot melt road marking paint.

[0051] Table 5: Test Results of Hot-Melt Marking Coatings in Examples and Comparative Cases Modified polyolefin resin composition A1 A2 A3 A4 A5 A6 A7 Softening point (°C) 122 118 124 129 128 122 126 Compressive strength (MPa) 18.0 18.2 18.4 19.1 18.8 18.1 18.9 Peel strength (N / 25mm) 128 132 131 139 140 135 135 Continued from Table 5: Modified polyolefin resin composition A8 A9 A10 A11 A12 Softening point (°C) 122 122 124 125 116 Compressive strength (MPa) 18.2 19.0 18.6 17.4 18.5 Peel strength (N / 25mm) 87 82 96 81 91 As shown in Examples 1-7, the peel strength of the hot-melt road marking paint modified with the modified polyolefin composition obtained by the one-pot method of the present invention is >120 N / 25 mm. The peel strength is even higher when the polar monomer grafting rate in the modified polyolefin composition is 1.2-1.7 wt%.

[0052] As shown in Comparative Example 1, the peel strength of hot-melt road marking paint is low when high-density polyethylene is used.

[0053] As shown in Comparative Example 2, the peel strength of hot-melt road marking paint is low when the grafting rate of polar monomers is too low.

[0054] As shown in Comparative Example 3, when the grafting rate of polar monomers is too high, the peel strength of hot-melt road marking paint decreases significantly.

[0055] As shown in Comparative Example 4, if the polyethylene wax content is too high, the peel strength of the hot-melt road marking paint is low, and the compressive strength is also poor.

[0056] As shown in Comparative Example 5, when the polyethylene wax content is too low, the peel strength of the hot-melt road marking paint is low.

[0057] Continued from Table 5: Modified polyolefin resin composition B1 B2 B3 B4 B5 B6 B7 Softening point (°C) 121 126 124 119 125 122 124 Compressive strength (MPa) 18.0 18.8 18.5 17.7 18.3 18.3 18.9 Peel strength (N / 25mm) 125 135 138 131 136 128 137 Continued from Table 5: Modified polyolefin resin composition B8 B9 B10 B11 B12 B13 Softening point (°C) 121 118 123 115 117 112 Compressive strength (MPa) 18.4 17.9 17.2 18.2 18.5 17.4 Peel strength (N / 25mm) 134 129 90 96 100 85 As can be seen from Examples 8-16, when the polar monomer grafting rate of the modified polyolefin resin composition obtained by melt blending polar monomer-grafted polyethylene and polar monomer-grafted polyethylene wax is within the range of the present invention, the purpose of the present invention can also be achieved. Preferably, the modified polyolefin resin composition obtained by one-pot method is preferred.

[0058] Furthermore, the peel strength is higher when the polar monomer grafting rate in the modified polyolefin composition is 1.2-1.7 wt%.

[0059] As can be seen from Comparative Example 6, when the content of maleic anhydride-grafted polyethylene wax is too high and not within the scope of protection of this invention, the hot-melt marking paint has low peel strength and low compressive strength.

[0060] As shown in Comparative Example 7, the peel strength of hot-melt road marking paint is low when it does not contain polar monomer-grafted polyethylene wax.

[0061] As shown in Comparative Example 8, the peel strength of hot-melt road marking paint is low when the content of polar monomer-grafted polyethylene is too high.

[0062] As shown in Comparative Example 9, when the hot-melt road marking paint does not contain polar monomer grafted polyethylene, the peel strength and compressive strength are low.

Claims

1. A hot-melt road marking paint, characterized in that, By weight, it includes the following components: 15-25 parts of petroleum resin; 3-7 parts of polyethylene wax; 3-7 parts titanium dioxide; 50-90 parts of calcium carbonate powder; 3-7 parts of modified polyolefin resin composition; The modified polyolefin resin composition comprises polar monomer-grafted polyethylene and polar monomer-grafted polyethylene wax. In the modified polyolefin resin composition, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%. The polyethylene in the polar monomer-grafted polyethylene is selected from at least one of LDPE and LLDPE. The polar monomer-grafted polyethylene and polar monomer-grafted polyethylene wax account for no less than 97 wt% of the total weight of the modified polyolefin resin composition. The polar monomer is selected from at least one of maleic anhydride, glycidyl methacrylate, and acrylamide; Based on a total of 90-102 parts of polar monomer grafted polyethylene and polar monomer grafted polyethylene wax, of which 67.5-90 parts are polyethylene segments and 9.5-30 parts are polyethylene wax segments.

2. The hot-melt road marking paint according to claim 1, characterized in that, In the modified polyolefin resin composition, the grafting rate of the polar monomer ranges from 1.2 to 1.7 wt%.

3. The hot-melt road marking paint according to claim 1, characterized in that, The polar monomer is selected from maleic anhydride.

4. The hot-melt road marking paint according to claim 1, characterized in that, The polyolefin resin composition further includes 0-2 parts by weight of an additive, wherein the additive is selected from at least one of antioxidants and lubricants.

5. The hot-melt road marking paint according to claim 1, characterized in that, In the aforementioned polar monomer-grafted polyethylene, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%; in the aforementioned polar monomer-grafted polyethylene wax, the grafting rate of the polar monomer ranges from 0.8 to 2.0 wt%.

6. The hot-melt road marking paint according to claim 5, characterized in that, In the aforementioned polar monomer-grafted polyethylene, the grafting rate of the polar monomer ranges from 1.2 to 1.7 wt%; in the aforementioned polar monomer-grafted polyethylene wax, the grafting rate of the polar monomer ranges from 1.2 to 1.7 wt%.

7. The hot-melt road marking paint according to claim 1, characterized in that, The modified polyolefin resin composition has a melt index of 50-500 g / 10 min at 190°C and 2.16 kg.

8. The hot-melt road marking paint according to claim 1, characterized in that, The petroleum resin is selected from at least one of C5 petroleum resin, C9 petroleum resin, hydrogenated C5 petroleum resin, and hydrogenated C9 petroleum resin.

9. The hot-melt road marking paint according to any one of claims 1-8, characterized in that, The method for preparing the modified polyolefin resin composition includes the following steps: mixing a polar monomer, an initiator, and an anti-crosslinking agent and dispersing them in a solvent, wherein the weight of the solvent is 0.5-2 times the total weight of the polar monomer, initiator, and anti-crosslinking agent; then mixing the mixture evenly with polyethylene and polyethylene wax; and extruding and granulating the mixture using a twin-screw extruder to obtain the modified polyolefin resin composition.

10. The hot-melt road marking paint according to claim 9, characterized in that, The initiator is selected from at least one of dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, and cumyl hydroperoxide; and / or The polyethylene wax has a weight-average molecular weight of 500-2000; and / or The polyethylene described above has a melt index of 50-100 g / 10 min at 190°C and 2.16 kg.