Modified polyolefin hot melt adhesive for upholstered furniture and preparation method thereof

Abstract

The invention discloses a modified polyolefin hot melt adhesive for upholstered furniture and a preparation method, and relates to the technical field of hot melt adhesive preparation. The preparation method of the hot melt adhesive comprises the following steps: heating, stirring and melting the polyolefin base resin to form a molten base material; adding tackifying resin, continuously stirring, mixing and uniformly melting to obtain a first mixed material; adding a wax reducing agent and an antioxidant, and uniformly stirring and mixing to obtain a second mixed material; adding a cross-linking agent and a catalyst, and carrying out dynamic vulcanization reaction; and cooling, pelletizing and drying to obtain the modified polyolefin hot melt adhesive product for upholstered furniture. According to the method, a stable system with a micro-crosslinking structure is formed, and the hot melt adhesive is endowed with excellent heat aging resistance and ultraviolet aging resistance. And meanwhile, the hot melt adhesive can be recycled, so that the environment-friendly advantage is outstanding. The preparation method disclosed by the invention is simple in process and suitable for industrial production, and the prepared hot melt adhesive is particularly suitable for bonding skins, fillers and the like of upholstered furniture such as high-grade sofas, mattresses and the like.

Description

Technical Field

[0001] This invention provides a modified polyolefin hot melt adhesive for upholstered furniture and its preparation method, relating to the field of hot melt adhesive preparation technology. Background Technology

[0002] In the modern upholstered furniture manufacturing industry, from common sofas and mattresses to various upholstered chairs, the production process has traditionally relied heavily on ethylene-vinyl acetate copolymer (EVA type) hot melt adhesive as the core bonding material. This choice is primarily due to the significant practical advantages of EVA type hot melt adhesive. Its excellent initial tack allows it to quickly adhere to the surfaces after application, effectively reducing the waiting time for curing. Furthermore, its rapid curing speed greatly improves assembly efficiency on furniture production lines, making it well-suited to the demands of large-scale, fast-paced upholstered furniture manufacturing. Therefore, it has long held a dominant position in the industry. However, a deeper analysis of the molecular structure of EVA type hot melt adhesive reveals that the abundant ester bonds in its molecular chain are a key bottleneck restricting its performance improvement. This structural characteristic directly results in poor performance in terms of heat resistance, aging resistance, and weather resistance. During the long-term use of upholstered furniture, especially when placed in environments such as living rooms and balconies where it may be exposed to sunlight and significant temperature fluctuations, EVA hot melt adhesives are highly susceptible to the combined effects of various environmental factors. These include the continuous heat in high-temperature summer environments, oxidation reactions caused by oxygen in the air, and ultraviolet radiation from daily sunlight. These factors continuously erode the molecular structure of the hot melt adhesive, causing it to gradually break down molecular chains. This leads to a series of deteriorations in appearance and performance, specifically manifested as noticeable yellowing of the adhesive layer and the gradual loss of elasticity and brittleness of the originally flexible adhesive layer. As these deteriorations intensify, the bonding strength of the hot melt adhesive will decrease significantly. In severe cases, the adhesive layer may even detach, and furniture parts may come apart. This not only affects the aesthetics and user experience of the upholstered furniture but also fails to meet the growing market demand for high-quality, long-life upholstered furniture. Meanwhile, from a material compatibility perspective, EVA material's compatibility with polyolefin furniture fabrics widely used in the current furniture industry, such as PP woven fabrics commonly used for sofa covers and PE imitation leather fabrics with a leather-like feel, is only at a general level. During the bonding process, additional surface treatment of the fabric is often required to ensure a basic bonding effect. This not only increases production steps and costs but may also further exacerbate the risk of bonding failure due to compatibility issues during long-term use. More importantly, EVA material itself is a non-recyclable polymer. After upholstered furniture is scrapped, a large amount of EVA adhesive waste is difficult to dispose of effectively, causing not only serious resource waste but also environmental pollution. This is severely contrary to the increasingly stringent environmental regulations worldwide and the sustainable development concepts actively advocated by various industries.Considering all these factors, developing a new type of hot melt adhesive that possesses excellent weather resistance to resist environmental erosion, outstanding durability to ensure long-term stable bonding, meets environmental protection requirements for recyclability, and maintains good compatibility with polyolefin substrates has become a key technical challenge that urgently needs to be solved in the upholstered furniture manufacturing industry. This is of great significance for promoting the technological upgrading and sustainable development of the entire industry. Summary of the Invention

[0003] To address the above problems, this invention provides a method for preparing a modified polyolefin hot melt adhesive for upholstered furniture, comprising the following steps:

[0004] S1. Melting of base resin: The polyolefin base resin is melted under heating and stirring conditions to form a molten base material;

[0005] S2. Addition and mixing of tackifying resin: Add tackifying resin to the molten base material and stir continuously at a constant temperature until it is completely melted and homogeneous to obtain a first mixture material;

[0006] S3. Addition and mixing of wax reducing agent and antioxidant: Add wax reducing agent and antioxidant to the first mixture, stir and mix evenly under vacuum conditions to obtain the second mixture;

[0007] S4. Dynamic vulcanization modification: A crosslinking agent and a catalyst are added to the second mixture, and a dynamic vulcanization reaction is carried out at a specific temperature to obtain a modified polyolefin hot melt adhesive melt;

[0008] S5. Molding and Packaging: The modified polyolefin hot melt adhesive melt is cooled, pelletized, and dried to obtain the modified polyolefin hot melt adhesive product for upholstered furniture.

[0009] Preferably, in step S1, the polyolefin base resin is a compound composition of metallocene linear low-density polyethylene (mLLDPE), polypropylene (PP), and thermoplastic elastomer (POE); wherein the mass ratio of metallocene linear low-density polyethylene, polypropylene, and thermoplastic elastomer is (40-60):(20-30):(20-30).

[0010] Preferably, in step S2, the tackifying resin is a compound composition of hydrogenated C9 petroleum resin, hydrogenated rosin glycerol ester, and terpene resin; wherein the mass ratio of hydrogenated C9 petroleum resin, hydrogenated rosin glycerol ester, and terpene resin is (50-70):(20-30):(10-20); and the total amount of the tackifying resin added is 40-60 parts by mass relative to 100 parts by mass of the polyolefin base resin.

[0011] Preferably, in step S3, the wax reducing agent is a compound composition of Fischer-Tropsch synthetic wax and microcrystalline wax; wherein the mass ratio of Fischer-Tropsch synthetic wax to microcrystalline wax is (70-80):(20-30); and the total amount of wax reducing agent added is 5-15 parts by mass relative to 100 parts by mass of the polyolefin base resin.

[0012] Preferably, in step S3, the antioxidant is a compound composition of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), and the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1; the total amount of antioxidant added is 0.5-1.5 parts by mass relative to 100 parts by mass of the polyolefin base resin.

[0013] Preferably, in step S4, the crosslinking agent is dicumyl peroxide (DCP), and its addition amount is 0.1-0.5 parts by weight relative to 100 parts by weight of the polyolefin base resin.

[0014] Preferably, in step S4, the catalyst is N,N-m-phenylenebismaleimide (HVA-2), and its addition amount is 0.05-0.2 parts by mass relative to 100 parts by mass of the polyolefin base resin.

[0015] Preferably, in step S1, the melting temperature is 150-170℃, the stirring speed is 100-200rpm, and the melting time is 20-40 minutes; in step S2, the mixing temperature is 160-180℃, the stirring speed is 200-300rpm, and the mixing time is 30-50 minutes; in step S3, the mixing temperature is 170-190℃, the stirring speed is 200-300rpm, the vacuum degree is -0.08--0.10MPa, and the mixing time is 20-40 minutes; in step S4, the temperature of the dynamic vulcanization reaction is 175-195℃, the reaction time is 5-15 minutes, and the stirring speed is 300-500rpm; in step S5, cooling is performed using a two-roll open mill with water cooling to below 40℃, and pelletizing is performed by cutting into particles with a particle size of 3-5mm.

[0016] The present invention also provides a modified polyolefin hot melt adhesive for upholstered furniture prepared by the above preparation method.

[0017] In addition, the above-mentioned method of using modified polyolefin hot melt adhesive for upholstered furniture includes: placing the hot melt adhesive particles in a hot melt glue gun or glue pot, heating it to 160-180℃ to melt it into a liquid state, then applying it to the surface of the upholstered furniture material to be bonded, bonding another material to it within an open time of 5-15 seconds, applying a pressure of 0.1-0.3MPa, maintaining the pressure and cooling to room temperature to complete the bonding.

[0018] The beneficial effects of this invention:

[0019] The modified polyolefin hot melt adhesive for upholstered furniture and its preparation method provided by this invention utilize a polyolefin compound system with a specific ratio as the matrix resin and innovatively introduce dynamic vulcanization crosslinking technology to construct a stable micro-crosslinked network structure within the hot melt adhesive, thereby completely overcoming the inherent defects of traditional EVA hot melt adhesives. The hot melt adhesive prepared by this invention exhibits extremely excellent heat resistance, aging resistance, and weather resistance. Its peel strength retention rate after thermo-oxidative aging and ultraviolet aging far exceeds that of traditional EVA products, significantly extending the service life of upholstered furniture. At the same time, this hot melt adhesive is composed entirely of polyolefins and their hydrogenated modifiers, exhibiting excellent compatibility with polyolefin fabrics commonly used in upholstered furniture, providing strong adhesion. Furthermore, the entire system does not contain highly polar functional groups, exhibiting high chemical stability. After the product's service life ends, it can be recycled and reused along with the substrate, achieving true environmental protection and meeting the stringent requirements of high-end upholstered furniture manufacturing for both adhesive performance and environmental friendliness. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0022] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.

[0023] Example 1

[0024] Weigh 50 parts by weight of metallocene linear low-density polyethylene (mLLDPE, ExxonMobil). TM 1018CA), 25 parts by weight of polypropylene (PP, SABIC, PP 575P), 25 parts by weight of thermoplastic polyolefin elastomer (POE, Dow Chemical, ENGAGE) TM8150) was added to a 500mL glass reactor equipped with a heating mantle, stirrer, and vacuum system. Heating and stirring were started, and the temperature was raised to 160°C. The stirring speed was set to 150 rpm, and stirring was continued for 30 minutes to completely melt the base resin into a homogeneous molten base. A total of 45 parts by weight of the thickening resin compound (including hydrogenated C9 petroleum resin (Eastotac Chemicals)) was added to the reactor. TM 30 parts of H-1420, hydrogenated rosin glycerol ester (Komalin Chemical Co., Ltd., Foral) TM 10 parts of AX-E, terpene resin (Yasuhara Chemical, YS Resin) TM Add 5 parts of PX-1000 to the reactor. Adjust and stabilize the reactor temperature at 170°C, increase the stirring speed to 250 rpm, and continue mixing for 40 minutes until the thickening resin is completely melted and uniformly dispersed to obtain the first mixture. Add 10 parts by weight of a wax reducing agent compound to the first mixture. The wax reducing agent compound includes Fischer-Tropsch synthetic wax (Sasol Chemicals). The mixture consisted of 7 parts FT-100, 3 parts microcrystalline wax (Honeywell), and 1.0 part by weight of an antioxidant compound, which included 0.5 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and 0.5 parts tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168). The exhaust valve of the reactor was closed, and the vacuum pump was turned on to evacuate the reactor to -0.09 MPa. Under these conditions, the temperature was maintained at 175°C, and the mixture was stirred at 250 rpm for 30 minutes to ensure thorough mixing and degassing, yielding a second mixture. While maintaining the vacuum and temperature conditions, 0.3 parts by weight of dicumyl peroxide (DCP, AkzoNobel) was added to the second mixture. 14) Add a crosslinking agent and 0.1 parts by weight of N,N'-m-phenyl bismaleimide (Shanghai Titan, HVA-2, CAS No.: 3006-93-7), and quickly increase the stirring speed to 400 rpm. Perform a dynamic vulcanization reaction at 175℃ for 10 minutes. Observe that the viscosity of the material initially increases slightly and then tends to stabilize, obtaining the modified polyolefin hot melt adhesive melt. Finally, depressurize the reactor and discharge the material. Quickly transfer the viscous melt to a two-roll mill with cooling water, roll it into thin sheets, and cool it to below 35℃. Cut it into uniform particles with a particle size of about 4 mm using a pelletizer, seal and package it to obtain the modified polyolefin hot melt adhesive product for upholstered furniture.

[0025] Example 2

[0026] Weigh 40 parts by weight of mLLDPE, 30 parts by weight of PP, and 30 parts by weight of POE and add them to a 500 mL glass reactor equipped with a heating mantle, stirrer, and vacuum system. Turn on the heating and stirring, control the temperature to rise to 155°C, set the stirring speed to 150 rpm, and continue stirring for 35 minutes to completely melt the base resin into a homogeneous molten base. Then, add a total of 50 parts by weight of the tackifying resin compound (35 parts by weight of hydrogenated C9 petroleum resin, 10 parts by weight of hydrogenated rosin glycerol ester, and 5 parts by weight of terpene resin) to the reactor, adjust and stabilize the reactor temperature at 165°C, increase the stirring speed to 250 rpm, and continue mixing for 45 minutes until the tackifying resin is completely melted and uniformly dispersed to obtain the first mixture. Add 8 parts by mass of a wax reducing agent compound (6.4 parts by mass of Fischer-Tropsch synthetic wax and 1.6 parts by mass of microcrystalline wax) and 0.8 parts by mass of an antioxidant compound (0.4 parts by mass of antioxidant 1010 and 0.4 parts by mass of antioxidant 168) to the first mixture. Close the exhaust valve of the reactor, turn on the vacuum pump, and evacuate the reactor to a vacuum of -0.08 MPa. Under these conditions, maintain the temperature at 180°C and continue mixing at a stirring speed of 250 rpm for 25 minutes to ensure that all components are fully mixed and that air bubbles are removed, thus obtaining the second mixture. Maintaining the vacuum and temperature conditions, add 0.2 parts by mass of DCP crosslinking agent and 0.15 parts by mass of HVA-2 catalyst to the second mixture, and quickly increase the stirring speed to 450 rpm. Perform a dynamic vulcanization reaction at 185°C for 8 minutes to obtain the modified polyolefin hot melt adhesive melt. Finally, the reactor is depressurized and the material is discharged. The viscous melt is quickly transferred to a two-roll open mill that has been cooled with water and rolled into thin sheets and cooled to below 35°C. The sheets are then cut into uniform particles with a particle size of about 4 mm by a pelletizer, sealed and packaged to obtain the modified polyolefin hot melt adhesive product for upholstered furniture.

[0027] Example 3

[0028] Weigh 60 parts by weight of mLLDPE, 20 parts by weight of PP, and 20 parts by weight of POE and add them to a 500 mL glass reactor equipped with a heating mantle, stirrer, and vacuum system. Turn on heating and stirring, control the temperature to rise to 165°C, set the stirring speed to 150 rpm, and continue stirring for 25 minutes to completely melt the base resin into a homogeneous molten base. Add a total of 55 parts by weight of the tackifying resin compound (including 38.5 parts by weight of hydrogenated C9 petroleum resin, 11 parts by weight of hydrogenated rosin glycerol ester, and 5.5 parts by weight of terpene resin) to the reactor, adjust and stabilize the reactor temperature at 175°C, increase the stirring speed to 250 rpm, and continue mixing for 35 minutes until the tackifying resin is completely melted and uniformly dispersed to obtain the first mixture. Add 12 parts by weight of a wax reducing agent compound (9.6 parts by weight of Fischer-Tropsch wax and 2.4 parts by weight of microcrystalline wax) and 1.2 parts by weight of an antioxidant compound (0.6 parts by weight of antioxidant 1010 and 0.6 parts by weight of antioxidant 168) to the first mixture. Close the exhaust valve of the reactor, turn on the vacuum pump, and evacuate the reactor to a vacuum of -0.10 MPa. Under these conditions, maintain the temperature at 185°C and continue mixing at a stirring speed of 250 rpm for 35 minutes to ensure that all components are fully mixed and degassed, thus obtaining the second mixture. Maintaining the vacuum and temperature conditions, add 0.4 parts by weight of DCP crosslinking agent and 0.08 parts by weight of HVA-2 catalyst to the second mixture, and quickly increase the stirring speed to 350 rpm. Perform a dynamic vulcanization reaction at 190°C for 12 minutes to obtain the modified polyolefin hot melt adhesive melt. Finally, the reactor is depressurized and the material is discharged. The viscous melt is quickly transferred to a two-roll open mill that has been cooled with water and rolled into thin sheets and cooled to below 35°C. The sheets are then cut into uniform particles with a particle size of about 4 mm by a pelletizer, sealed and packaged to obtain the modified polyolefin hot melt adhesive product for upholstered furniture.

[0029] Comparative Example 1 (Traditional EVA hot melt adhesive)

[0030] A commercially available general-purpose EVA hot melt adhesive (Henkel Technomelt Supra115, Germany) commonly used in upholstered furniture was used as a comparison sample.

[0031] Comparative Example 2 (without dynamic vulcanization modification)

[0032] The difference from Example 1 is that step S4 is omitted, that is, the crosslinking agent DCP and catalyst HVA-2 are not added, and the material is directly discharged, cooled and pelletized after completing step S3 mixing.

[0033] Comparative Example 3 (Single Polyolefin Matrix)

[0034] The difference from Example 1 is that all the polyolefin base resin is replaced with 100 parts by weight of mLLDPE, and PP and POE are omitted.

[0035] Comparative Example 4 (Different Crosslinking Systems)

[0036] The difference from Example 1 is that the crosslinking agent DCP is replaced with an equal mass of sulfur vulcanization system [accelerator DM (flexsys, [0.15 parts MOR, 1 part zinc oxide, 0.5 parts stearic acid (Bairloch), 0.3 parts sulfur], and omitting catalyst HVA-2, the dynamic vulcanization temperature was adjusted to 160℃ and the reaction was carried out for 20 minutes.

[0037] The performance of the products prepared in the examples and comparative examples was tested or calculated using the following methods, and the results are shown in Table 1.

[0038] Detection method:

[0039] Initial peel strength: Hot melt adhesive granules are melted at 180℃ and coated onto a standard PP substrate (100mm×25mm×2mm) with a coating weight of 150g / m². 2 Immediately overlap and bond it with another identical PP substrate, with an overlap area of ​​25mm × 25mm. Cool to room temperature under 0.2MPa pressure to cure, preparing a T-type peel test specimen. Test the specimen on a universal testing machine (Instron 3365) according to GB / T 2791-1995 "Test Method for T-Peel Strength of Adhesives - Flexible Materials to Flexible Materials", with a tensile speed of 100mm / min. The average value of 5 specimens is taken as the reported value, in Newtons per 25mm (N / 25mm).

[0040] Peel strength retention rate after thermo-oxidative aging: The prepared T-type peel samples were placed in a forced-air drying oven and aged continuously at 120℃ for 168 hours. After removal, they were placed in a standard laboratory environment (23±2℃, 50±5%RH) for 24 hours to equilibrate. Then, their peel strength was tested using the same method as above. Retention rate (%) = (average peel strength after aging / average initial peel strength) × 100%.

[0041] Peel strength retention rate after UV aging: The prepared T-shaped peel samples were placed in a QUV accelerated aging test chamber (Q-LAB, UVA-340 lamp) and tested according to GB / T 14522-2008 "Artificial Climate Aging Test Method for Plastics, Coatings and Rubber Materials for Mechanical Industry Products - Fluorescent Ultraviolet Lamp". The cyclic conditions were: 8 hours of UV irradiation at 60℃, followed by 4 hours of condensation at 50℃. After a cumulative irradiation of 500 hours, the samples were removed and placed in a standard laboratory environment for 24 hours to equilibrate. Then, the peel strength was tested using the same method as above. Retention rate (%) = (average peel strength after aging / average initial peel strength) × 100%.

[0042] Melt viscosity: Tested using a rotational viscometer (Brookfield RVDV-II+Pro) according to GB / T2794-2013 "Determination of Viscosity of Adhesives". Take an appropriate amount of hot melt adhesive sample into a standard sample cup, and under constant temperature of 180℃, select a suitable rotor (such as SC4-27). After the reading stabilizes, record the viscosity value in millipascal-seconds (mPa·s).

[0043] Softening point: The softening point was determined using a ring and ball method softening point tester, referring to GB / T 15332-1994 "Determination of Softening Point of Hot Melt Adhesives - Ring and Ball Method". The hot melt adhesive sample was heated and melted, then poured into a specified copper ring. After cooling, the sample was leveled and placed in a beaker filled with glycerin. A steel ball was placed on the sample, and heating was carried out at a rate of 5°C / min. The temperature at which the steel ball penetrated the sample and touched the bottom was recorded as the softening point, expressed in degrees Celsius (°C).

[0044] Recyclability: The hot melt adhesive granules of this invention are mixed with an equal mass of virgin polypropylene (PP) in a high-speed mixer for 2 minutes. Then, the mixture is melt-blended, extruded, cooled, and pelletized using a twin-screw extruder (processing temperature 180-200℃) to obtain recycled material. The smoothness of the blending and pelletizing process and the uniformity of the resulting granules are observed. If the process is completed smoothly and the granules are uniform, it is determined to be "recyclable"; if phase separation, degradation, or inability to extrude or pelletize smoothly occurs, it is determined to be "no".

[0045] Table 1 Test Results

[0046]

[0047] As can be seen, the modified polyolefin hot melt adhesive provided by this invention (Examples 1-3) has an initial peel strength comparable to that of traditional EVA hot melt adhesive (Comparative Example 1), but its core advantage lies in its extremely excellent aging resistance. After harsh thermo-oxidative aging and ultraviolet aging, its peel strength retention rate is as high as 90% or more, far superior to Comparative Example 1 (retention rate of only 50-60%). This fully demonstrates that the micro-crosslinked structure constructed by dynamic vulcanization in this invention effectively resists molecular chain degradation caused by heat and ultraviolet radiation, solving the core problem pointed out in the background art. The various properties of Comparative Example 2 (without dynamic vulcanization), especially its aging resistance, are significantly lower than those of the embodiments of this invention, confirming the effectiveness of the dynamic vulcanization step. This is a key innovation of the present invention and is indispensable. The initial strength and aging resistance of Comparative Example 3 (single matrix) are inferior to those of the examples, indicating that the specific synergistic effect of the mLLDPE / PP / POE compound is crucial to the overall performance. Comparative Example 4 (different crosslinking systems) exhibited problems such as excessively high melt viscosity, deteriorated processability, and non-recyclability, demonstrating the unique advantages of the DCP / HVA-2 peroxide crosslinking system compared to the traditional sulfur system in this application. It can achieve effective crosslinking to improve aging resistance while achieving the best balance between processability and recyclability. Furthermore, all examples can be smoothly blended and granulated with PP substrates, confirming their excellent environmentally friendly and recyclable characteristics. In summary, the present invention, through specific component selection, proportioning, and a key dynamic vulcanization process, obtains a novel hot melt adhesive with excellent overall performance, particularly outstanding durability, and environmental friendliness.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0049] The present invention and its embodiments have been described above. This description is not restrictive, but merely one embodiment of the present invention, and the actual application is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a modified polyolefin hot melt adhesive for upholstered furniture, characterized in that, Includes the following steps: S1. Base Resin Melting: The polyolefin base resin is melted under heating and stirring conditions to form a molten base material; S2. Addition and mixing of tackifying resin: Add tackifying resin to the molten base material and stir continuously at a constant temperature until it is completely melted and homogeneous to obtain a first mixture material; S3. Addition and mixing of wax reducing agent and antioxidant: Add wax reducing agent and antioxidant to the first mixture, stir and mix evenly under vacuum conditions to obtain the second mixture; S4. Dynamic vulcanization modification: A crosslinking agent and a catalyst are added to the second mixture, and a dynamic vulcanization reaction is carried out at a specific temperature to obtain a modified polyolefin hot melt adhesive melt; S5. Molding and Packaging: The modified polyolefin hot melt adhesive melt is cooled, pelletized, and dried to obtain the modified polyolefin hot melt adhesive product for upholstered furniture.

2. The preparation method according to claim 1, characterized in that, In step S1, the polyolefin base resin is a compound composition of metallocene linear low-density polyethylene, polypropylene and thermoplastic elastomer; wherein the mass ratio of metallocene linear low-density polyethylene, polypropylene and thermoplastic elastomer is (40-60):(20-30):(20-30).

3. The preparation method according to claim 1, characterized in that, In step S2, the tackifying resin is a compound composition of hydrogenated C9 petroleum resin, hydrogenated rosin glycerol ester and terpene resin; wherein the mass ratio of hydrogenated C9 petroleum resin, hydrogenated rosin glycerol ester and terpene resin is (50-70):(20-30):(10-20); the total amount of the tackifying resin added is 40-60 parts by mass relative to 100 parts by mass of the polyolefin base resin.

4. The preparation method according to claim 1, characterized in that, In step S3, the wax reducing agent is a compound composition of Fischer-Tropsch synthetic wax and microcrystalline wax; wherein the mass ratio of Fischer-Tropsch synthetic wax to microcrystalline wax is (70-80):(20-30); and the total amount of wax reducing agent added is 5-15 parts by mass relative to 100 parts by mass of the polyolefin base resin.

5. The preparation method according to claim 1, characterized in that, In step S3, the antioxidant is a compound composition of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite, and the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1; the total amount of antioxidant added is 0.5-1.5 parts by mass relative to 100 parts by mass of the polyolefin base resin.

6. The preparation method according to claim 1, characterized in that, In step S4, the crosslinking agent is dicumyl peroxide, and its addition amount is 0.1-0.5 parts by mass relative to 100 parts by mass of the polyolefin base resin.

7. The preparation method according to claim 1 or 5, characterized in that, In step S4, the catalyst is N,N-m-phenylenebismaleimide, and its addition amount is 0.05-0.2 parts by mass relative to 100 parts by mass of the polyolefin base resin.

8. The preparation method according to claim 1, characterized in that, In step S1, the melting temperature is 150-170℃, the stirring speed is 100-200 rpm, and the melting time is 20-40 minutes; in step S2, the mixing temperature is 160-180℃, the stirring speed is 200-300 rpm, and the mixing time is 30-50 minutes; in step S3, the mixing temperature is 170-190℃, the stirring speed is 200-300 rpm, the vacuum degree is -0.08 - -0.10 MPa, and the mixing time is 20-40 minutes; in step S4, the temperature of the dynamic vulcanization reaction is 175-195℃, the reaction time is 5-15 minutes, and the stirring speed is 300-500 rpm; in step S5, cooling is performed using a two-roll open mill with water cooling to below 40℃, and pelletizing is done by cutting into particles with a particle size of 3-5 mm.

9. A modified polyolefin hot melt adhesive for upholstered furniture prepared by the preparation method according to any one of claims 1-8.

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