Hot melt adhesive and preparation method thereof

Abstract

The hot melt adhesive is prepared from the following raw materials in parts by weight: 40 to 50 parts of resin polymer, 20 to 30 parts of polyol polymer, 10 to 20 parts of POE (Polyolefin Elastomer), 5 to 10 parts of wax material and 5 to 10 parts of auxiliary agent, the preparation method comprises the following steps: S1, raw material preparation: preparing a resin polymer, a polyol polymer, a POE polyolefin elastomer, a wax material and an auxiliary agent; s2, mixing and stirring: putting the resin polymer, the polyol polymer, the POE polyolefin elastomer and the wax material into stirring equipment, and uniformly mixing; s3, reaction synthesis: carrying out a dehydration reaction under the assistance of nitrogen protection at a certain temperature and vacuum degree; s4, adding auxiliary materials: after the reaction is completed, adding the prepared auxiliary materials, and continuously stirring for 2-4 hours; s5, final treatment: cooling the reacted hot melt adhesive to normal temperature, discharging and sub-packaging, in the preparation process of the hot melt adhesive, the heat resistance of the hot melt adhesive is improved in the resin polymer, and the tensile strength is ensured by the POE polyolefin elastomer.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot melt adhesives, and particularly relates to a hot melt adhesive and a preparation method thereof. Background Art

[0002] A hot melt adhesive is a plastic solid adhesive that melts into a liquid when heated and quickly solidifies when cooled to achieve bonding. The hot melt adhesive is solid at room temperature, which is convenient for packaging, transportation and storage. The hot melt adhesive has the characteristics of non-toxic, odorless, solvent-free, pollution-free, and environmentally friendly, and is known as the "green adhesive". It also has the advantages of simple production process, high added value, large bonding strength, and fast speed, and is particularly suitable for use on continuous production lines. The application fields of hot melt adhesives are very wide, including but not limited to bookbinding, bonding of cloth shoes and hats, etc.

[0003] When the existing hot melt adhesives are used for bonding, their high-temperature resistance, waterproof effect and tensile effect are not good. The hot melt adhesives may be used in high-temperature or humid and rainy environments. If these performances cannot be met, it will lead to poor use experience, reduce the value, and thus be unable to gain a foothold in the market. Therefore, it is necessary to optimize its performance. Summary of the Invention

[0004] Aiming at the problems raised in the above background art, the purpose of the present invention is to provide a hot melt adhesive and a preparation method thereof.

[0005] To achieve the above technical purpose, the technical scheme adopted by the present invention is as follows:

[0006] A hot melt adhesive, comprising the following raw materials in parts by weight:

[0007] 40 - 50 parts of resin polymer, 20 - 30 parts of polyol polymer, 10 - 20 parts of POE polyolefin elastomer, 5 - 10 parts of wax material, and 5 - 10 parts of auxiliary agent;

[0008] The resin polymer includes EVA resin, epoxy resin, petroleum resin and rosin resin, and the ratio is 1:1:0.3:0.5;

[0009] The polyol polymer includes polyester polyol and polyether polyol, and the ratio is 1:0.7. The polyester polyol is prepared by the esterification reaction of dibasic acid and diol, and the polyether polyol is prepared by the addition polymerization reaction of initiator with ethylene oxide, propylene oxide and butylene oxide in the presence of a catalyst;

[0010] The POE polyolefin elastomer is prepared by the random copolymerization reaction of ethylene and higher carbon alpha-olefins using a metallocene catalyst;

[0011] The wax material includes animal wax, plant wax and mineral wax, and the ratio is 0.5:0.7:1;

[0012] The auxiliary agents include antioxidants, catalysts, modifiers, tackifiers and viscosity regulators, with a ratio of 1:0.6:0.3:0.3:0.2;

[0013] A method for preparing hot melt adhesive, comprising the following preparation steps:

[0014] S1. Raw material preparation:

[0015] Prepare resin polymers, polyol polymers, POE polyolefin elastomers, waxes and auxiliary agents;

[0016] S2. Mixing and stirring:

[0017] Put the resin polymer, polyol polymer, POE polyolefin elastomer and wax into a stirring device and mix evenly;

[0018] S3. Reaction synthesis:

[0019] Under a certain temperature and vacuum degree, carry out a dehydration reaction with the assistance of nitrogen protection;

[0020] S4. Adding auxiliary materials:

[0021] After the reaction is completed, add the prepared auxiliary agents and continue stirring for 2 - 4 h;

[0022] S5. Final treatment:

[0023] Cool the completed hot melt adhesive to room temperature, and carry out discharging and packaging.

[0024] Further defined, the resin polymer includes PHBV resin and APAO resin, wherein the content of HV in the PHBV resin is 5% - 12% (mol). The content of HV in the PHBV resin mainly affects the physical properties and biodegradability of the hot melt adhesive. Excessive content will affect the flexibility, strength and heat resistance of the hot melt adhesive, but a small amount of content can improve the biodegradation rate of the hot melt adhesive, which is beneficial in terms of environmental protection. The addition of a small amount of APAO resin can improve the viscosity, thermal stability, softening point and safety of the hot melt adhesive, but excessive addition of APAO resin will affect the cohesive strength of the hot melt adhesive, resulting in the brittleness of the adhesive layer and thus affecting its overall adhesion performance.

[0025] Further defined, the initiator used to prepare the polyether polyol is one or more of glycerol, propylene glycol, ethylene glycol, and trimethylolpropane. Glycerol, propylene glycol, ethylene glycol, and trimethylolpropane are all common chemical raw materials, which are easy to purchase and store. This is conducive to reducing production costs and ensuring production stability. These initiators undergo a polyaddition reaction with raw materials such as ethylene oxide and propylene oxide under the action of a catalyst. By adjusting conditions such as the feeding method, dosage ratio, and feeding sequence, key performance parameters such as the molecular weight and functionality of the polyether polyol can be precisely controlled, thereby meeting different requirements for the preparation of hot melt adhesives. Using different initiators can prepare polyether polyols with different properties. For example, using glycerol as the initiator can prepare a low-functionality, long-chain polyether polyol, which is suitable for applications such as soft foams, while using trimethylolpropane as the initiator can prepare a high-functionality, high-hydroxyl-value polyether polyol, which is suitable for formulations such as rigid foams. This diversity makes polyether polyols have broad application prospects in the preparation of hot melt adhesives.

[0026] Further defined, the catalyst used to prepare the polyether polyol is one of potassium hydroxide or sodium hydroxide. Potassium hydroxide and sodium hydroxide are both strong bases. They can provide a strong alkaline environment, effectively reduce the reaction activation energy, and thus accelerate the ring-opening polymerization reaction of monomers such as ethylene oxide, improving the production efficiency of polyether polyols. During the catalytic process, by precisely controlling the dosage of potassium hydroxide or sodium hydroxide and reaction conditions (such as temperature, pressure, stirring speed, etc.), precise regulation of key performance parameters such as the molecular weight and functionality of the polyether polyol can be achieved, meeting different requirements for the preparation of hot melt adhesives. The production process of polyether polyols catalyzed by potassium hydroxide has been developed for many years, with mature and stable technology. Because its product has a narrow molecular weight distribution and good process stability, it is conducive to ensuring the quality stability of hot melt adhesives.

[0027] Further defined, in the wax material, the animal wax includes one or more of Chinese insect wax, beeswax, spermaceti wax and lanolin wax; the plant wax includes one or more of carnauba wax, wood wax, myrica wax, candelilla wax, Japan wax and jojoba oil; the mineral wax includes one of paraffin wax and microcrystalline wax. Chinese insect wax, beeswax, spermaceti wax and lanolin wax all have good wettability and adhesiveness, which can enhance the wetting and bonding effects of the hot melt adhesive on the substrate. At the same time, they can also improve the flexibility and weather resistance of the hot melt adhesive to a certain extent. Carnauba wax, wood wax, myrica wax, candelilla wax, Japan wax and jojoba oil have natural antioxidant properties and stability, which can extend the storage life of the hot melt adhesive. In addition, they can also adjust the hardness and viscosity of the hot melt adhesive to make it more suitable for different application scenarios. The main functions of paraffin wax and microcrystalline wax are to adjust the hardness and melting point of the hot melt adhesive. By adding different proportions of mineral wax, the curing time and hardness after curing of the hot melt adhesive can be precisely controlled to meet different bonding requirements. At the same time, the cost of mineral wax is relatively low, which helps to reduce the production cost of the hot melt adhesive.

[0028] Further defined, in the auxiliary agent, the antioxidant includes one or more of epoxy compounds, phosphate ester compounds, dibutyl p-cresol and triphenyl phosphite; the catalyst includes one of organotin, organotitanium and acid anhydride; the modifier includes one or more of cellulose fiber, glass fiber, carbon fiber, wollastonite, talc powder, silica, antibacterial agent and flame retardant; the tackifier includes one of polymer tackifiers mainly made of PVC, PS and ABS materials, polyamide tackifiers mainly made of nylon, Kevlar and PEEK materials, polyurethane tackifiers mainly made of MDI and TDI materials, and silicone tackifiers mainly made of dimethylsilane and water glass materials; the viscosity regulator includes one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, Fischer-Tropsch wax, Sasol wax, hyperbranched polymer, APAO, ethylene bisstearamide, EVA, urea, hydroxylamine hydrochloride, hydroxylamine sulfate and cyclohexanol, which can achieve the effects of increasing bonding performance, adjusting melting viscosity, preventing oxidation and decomposition, improving wettability and accelerating curing speed.

[0029] Further defined, in step S2, the stirring equipment is a stirring equipment with vacuum degassing function and temperature regulation function. During the preparation process of the hot melt adhesive, the materials may be mixed with some gases or generate bubbles during heating and mixing. If these bubbles and impurities are not removed, they will affect the quality and performance of the hot melt adhesive, such as reducing its strength and durability. Therefore, these bubbles and impurities can be effectively removed through vacuum treatment to make the density of the hot melt adhesive more uniform, thereby improving its overall quality; the regulation of temperature is to ensure that all raw materials can melt and facilitate stirring and mixing.

[0030] Further limitation: In step S3, the stirring process is carried out in an environment with a vacuum degree of 0.01 - 0.05 Mpa and a rotation speed of 400 r / min. The stirring temperature is a stepped variable temperature environment, and nitrogen is added during this period. Specifically:

[0031] In the first stage, it is carried out at 40 - 50 °C for 2 - 4 h;

[0032] In the second stage, it is heated to 60 - 80 °C and carried out for 1 - 2 h;

[0033] In the third stage, it is heated to 100 - 130 °C and carried out for 2 - 3 h;

[0034] In the fourth stage, it is cooled to 70 - 75 °C and nitrogen is introduced;

[0035] In the fifth stage, it is heated to 80 - 100 °C and carried out for 3 - 4 h;

[0036] In the sixth stage, it is heated to 105 - 120 °C for vacuum degassing for 0.5 - 1 h;

[0037] Because there are multiple materials, and the melting points of each material are not the same, the temperature-controlled stirring in stages can effectively ensure the melting of all materials, exert their properties, and ensure that the properties of the base material after mixing reach the expected corresponding effects.

[0038] Further limitation: In step S5, before discharging and sub-packaging, the hot melt adhesive is subjected to aging treatment. Aging treatment can improve the adhesion and hardness of the hot melt adhesive, increase its heat resistance, cold resistance and corrosion resistance, reduce the shrinkage rate and shrinkage porosity, improve the bonding quality, so as to better exert the performance of the hot melt adhesive and improve the bonding efficiency and quality.

[0039] Advantages of adopting the present invention:

[0040] Resin polymers, polyol polymers and POE polyolefin elastomers, as the main components of the hot melt adhesive, endow the hot melt adhesive with good mechanical properties, flexibility and heat resistance characteristics. The addition of wax materials and additives further adjusts the melting viscosity and processing performance of the hot melt adhesive, making it more adaptable to different application scenarios and requirements. Specifically, the modified EVA resin, epoxy resin and rosin resin in the resin polymer improve the heat resistance of the hot melt adhesive, the polyester polyol improves the heat resistance of the hot melt adhesive, and the polyether polyol enhances the water resistance of the hot melt adhesive;

[0041] In the preparation process of this hot melt adhesive, POE polyolefin elastomer is added. The POE polyolefin elastomer has excellent elasticity, which enables the hot melt adhesive made from it to better adapt to materials with different shapes and surfaces during the bonding process, providing stronger adhesion and more durable bonding effect. Moreover, the macromolecular chain of the POE polyolefin elastomer has a saturated structure and relatively few tertiary carbon atoms in the molecular structure, so it has excellent heat aging and ultraviolet resistance. This makes the hot melt adhesive made from it maintain stable performance in high-temperature environments, not easy to age or fail. And the POE polyolefin elastomer has good impact efficiency, which can significantly improve the impact resistance of the hot melt adhesive. Under various environmental conditions, the POE hot melt adhesive can maintain good viscosity and is not easy to fall off or be damaged due to external force impact. The glass transition temperature of the POE polyolefin elastomer is very low and the elongation at break is large, which is suitable for use in low-temperature environments. This makes the hot melt adhesive made from it maintain good flexibility and bonding performance under low-temperature conditions, without embrittlement or cracking phenomenon. Detailed implementation mode

[0042] In order to enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be further described below in conjunction with embodiments.

[0043] A kind of hot melt adhesive of the present invention comprises the following raw materials in parts by weight:

[0044] 40 - 50 parts of resin polymer, 20 - 30 parts of polyol polymer, 10 - 20 parts of POE polyolefin elastomer, 5 - 10 parts of wax material and 5 - 10 parts of auxiliary agent;

[0045] The resin polymer includes EVA resin, epoxy resin, petroleum resin and rosin resin, and the ratio is 1:1:0.3:0.5;

[0046] The polyol polymer includes polyester polyol and polyether polyol, and the ratio is 1:0.7. The polyester polyol is prepared by the esterification reaction of dibasic acid and dibasic alcohol, and the polyether polyol is prepared by the addition polymerization reaction of initiator with ethylene oxide, propylene oxide and butylene oxide in the presence of a catalyst;

[0047] The POE polyolefin elastomer is prepared by the random copolymerization reaction of ethylene and higher carbon α-olefins using a metallocene catalyst;

[0048] The wax material includes animal wax, plant wax and mineral wax, and the ratio is: 0.5:0.7:1;

[0049] The auxiliary agent includes antioxidant, catalyst, modifier, tackifier and viscosity regulator, and the ratio is 1:0.6:0.3:0.3:0.2;

[0050] A method for preparing a hot melt adhesive, comprising the following preparation steps:

[0051] S1. Raw material preparation:

[0052] Prepare resin polymer, polyol polymer, POE polyolefin elastomer, wax and additives;

[0053] S2. Mixing and stirring:

[0054] Put the resin polymer, polyol polymer, POE polyolefin elastomer and wax into the stirring equipment and mix evenly;

[0055] S3. Reaction synthesis:

[0056] Under a certain temperature and vacuum degree, assist nitrogen protection to carry out dehydration reaction;

[0057] S4. Adding auxiliary materials:

[0058] After the reaction is completed, add the prepared additives and continue stirring for 2 - 4h;

[0059] S5. Final treatment:

[0060] Cool the completed hot melt adhesive to room temperature, and carry out discharging and packaging.

[0061] Example 1:

[0062] Prepare 40 parts of resin polymer, 20 parts of polyol polymer, 10 parts of POE polyolefin elastomer, 5 parts of wax and 5 parts of additives;

[0063] Put 40 parts of resin polymer, 20 parts of polyol polymer, 10 parts of POE polyolefin elastomer and 5 parts of wax into the stirring equipment for mixing. The vacuum degree of the stirring equipment is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9h with stepped temperature control regulation. During the temperature range of 70 - 75°C, nitrogen protection is introduced, and finally degassing is carried out for 1h to obtain the dehydrated matrix material. Then add 5 parts of additives and continue stirring for 2h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0064] Example 2:

[0065] Prepare 50 parts of resin polymer, 30 parts of polyol polymer, 20 parts of POE polyolefin elastomer, 10 parts of wax and 10 parts of additives;

[0066] Put 50 parts of resin polymer, 30 parts of polyol polymer, 20 parts of POE polyolefin elastomer and 10 parts of wax into a stirring device for mixing. The vacuum degree of the stirring device is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9 h with stepwise temperature control adjustment. During the temperature range of 70 - 75 °C, nitrogen is introduced for protection, and finally degassing is carried out for 1 h to obtain the dehydrated matrix material. Then add 10 parts of additives and continue stirring for 2 h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0067] Example 3:

[0068] Prepare 45 parts of resin polymer, 25 parts of polyol polymer, 15 parts of POE polyolefin elastomer, 7 parts of wax and 7 parts of additives;

[0069] Put 50 parts of resin polymer, 30 parts of polyol polymer, 20 parts of POE polyolefin elastomer and 10 parts of wax into a stirring device for mixing. The vacuum degree of the stirring device is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9 h with stepwise temperature control adjustment. During the temperature range of 70 - 75 °C, nitrogen is introduced for protection, and finally degassing is carried out for 1 h to obtain the dehydrated matrix material. Then add 7 parts of additives and continue stirring for 2 h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0070] Comparative Example 1:

[0071] Prepare 40 parts of resin polymer, 30 parts of polyol polymer, 20 parts of POE polyolefin elastomer, 10 parts of wax and 10 parts of additives;

[0072] Put 40 parts of resin polymer, 30 parts of polyol polymer, 20 parts of POE polyolefin elastomer and 10 parts of wax into a stirring device for mixing. The vacuum degree of the stirring device is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9 h with stepwise temperature control adjustment. During the temperature range of 70 - 75 °C, nitrogen is introduced for protection, and finally degassing is carried out for 1 h to obtain the dehydrated matrix material. Then add 10 parts of additives and continue stirring for 2 h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0073] Comparative Example 2:

[0074] Prepare 50 parts of resin polymer, 20 parts of polyol polymer, 10 parts of POE polyolefin elastomer, 5 parts of wax and 5 parts of additives;

[0075] Put 50 parts of resin polymer, 20 parts of polyol polymer, 10 parts of POE polyolefin elastomer and 5 parts of wax into a stirring device for mixing. The vacuum degree of the stirring device is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9 h with stepped temperature control adjustment. During the temperature range of 70 - 75 °C, nitrogen is introduced for protection. Finally, defoaming is carried out for 1 h to obtain the dehydrated matrix material. Then, 5 parts of additives are added and stirring is continued for 2 h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0076] Comparative Example 3:

[0077] Prepare 40 parts of resin polymer, 30 parts of polyol polymer, 10 parts of wax and 10 parts of additives;

[0078] Put 40 parts of resin polymer, 30 parts of polyol polymer and 10 parts of wax into a stirring device for mixing. The vacuum degree of the stirring device is 0.01 - 0.05 Mpa, the rotation speed is 400 r / min, and the total stirring and mixing is carried out for 9 h with stepped temperature control adjustment. During the temperature range of 70 - 75 °C, nitrogen is introduced for protection. Finally, defoaming is carried out for 1 h to obtain the dehydrated matrix material. Then, 10 parts of additives are added and stirring is continued for 2 h. The finished product after stirring is the final hot melt adhesive, and it can be discharged and packaged according to requirements.

[0079] The performance data of the examples and comparative examples are as follows in the table:

[0080]

[0081] In the above table:

[0082] Example 1 shows the performance data of the hot melt adhesive prepared with the minimum number of parts;

[0083] Example 2 shows the performance data of the hot melt adhesive prepared with the maximum number of parts;

[0084] Example 3 shows the performance data of the hot melt adhesive prepared with moderate number of parts;

[0085] Comparative Example 1 shows the performance data with an increase in the number of parts of polyol polymer and POE polyolefin elastomer compared to Example 1;

[0086] Comparative Example 2 shows the performance data with a decrease in the number of parts of polyol polymer and POE polyolefin elastomer compared to Example 2;

[0087] Comparative Example 3 shows the performance data with the removal of the number of parts of POE polyolefin elastomer compared to Example 1;

[0088] As can be seen from the data in the table, all the data of the hot melt adhesive prepared with the complete materials meet or even exceed the basic requirements of the hot melt adhesive. However, in Comparative Example 3, all the data of the finished hot melt adhesive with the POE polyolefin elastomer removed have decreased, especially the heat resistance and tensile strength have decreased significantly;

[0089] As can be seen from Examples 1 to 3, the increase of each material has improved the data of the finished hot melt adhesive;

[0090] Comparing Example 1 with Comparative Example 1, the addition of the polyol polymer and the POE polyolefin elastomer has enhanced both the heat resistance and the tensile strength;

[0091] Comparing Example 2 with Comparative Example 2, the reduction of the polyol polymer and the POE polyolefin elastomer has reduced both the heat resistance and the tensile strength;

[0092] Therefore, the polyol polymer and the POE polyolefin elastomer have an impact on the overall heat resistance and tensile strength of the hot melt adhesive. Especially the addition of the POE polyolefin elastomer has a greater impact on the tensile strength of the hot melt adhesive.

[0093] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A hot melt adhesive, characterized in that: The composition comprises the following raw materials in parts by weight: 40-50 parts of resin polymer, 20-30 parts of polyol polymer, 10-20 parts of POE polyolefin elastomer, 5-10 parts of wax material and 5-10 parts of additives; The resin polymer includes EVA resin, epoxy resin, petroleum resin and rosin resin in a ratio of 1:1:0.3:0.5; The polyol polymer includes polyester polyol and polyether polyol in a ratio of 1:0.7, wherein the polyester polyol is prepared by esterification reaction of dibasic acid and diol, and the polyether polyol is prepared by addition polymerization reaction of initiator with ethylene oxide, propylene oxide and butylene oxide in the presence of catalyst; The POE polyolefin elastomer is prepared by random copolymerization of ethylene and high carbon α-olefin using a metallocene catalyst; The wax material includes animal wax, vegetable wax and mineral wax in a ratio of 0.5:0.7:1; The auxiliary agents include antioxidants, catalysts, modifiers, tackifiers and viscosity regulators in a ratio of 1:0.6:0.3:0.3:0.

2.

2. A hot melt adhesive according to claim 1, characterized in that: The resin polymer comprises PHBV resin and APAO resin, wherein the content of HV in the PHBV resin is 5% to 12% (mol).

3. A hot melt adhesive according to claim 1, characterized in that: The initiator used to prepare the polyether polyol is one or more of glycerol, propylene glycol, ethylene glycol and glycerol trimethylolpropane.

4. A hot melt adhesive according to claim 1, characterized in that: The catalyst used to prepare the polyether polyol is one of potassium hydroxide and sodium hydroxide.

5. The hot melt adhesive according to claim 1, characterized in that: Among the wax materials, the animal wax includes one or more of insect wax, beeswax, spermaceti and wool wax, the plant wax includes one or more of carnauba wax, wood wax, bayberry wax, candelilla wax, Japan refined wax and jojoba oil, and the mineral wax includes one of paraffin wax and microcrystalline wax.

6. The hot melt adhesive according to claim 1, characterized in that: Among the auxiliary agents, the antioxidant includes one or more of epoxy compounds, phosphate compounds, di-tert-butyl-p-cresol and triphenyl phosphite, the catalyst includes one of organic tin, organic titanium and acid anhydride, the modifier includes one or more of cellulose fiber, glass fiber, carbon fiber, wollastonite, talc, silicon dioxide, antibacterial agent and flame retardant, the tackifier includes one of polymer tackifier mainly made of PVC, PS and ABS materials, polyamide tackifier mainly made of nylon, Kevlar and PEEK materials, polyurethane tackifier mainly made of MDI and TDI materials and silicone tackifier mainly made of dimethyl silane and water glass materials, and the viscosity regulator includes one or more of polyethylene wax, oxidized polyethylene wax, polypropylene wax, Fischer-Tropsch wax, Sasol wax, hyperbranched polymer, APAO, ethylenebisstearamide, EVA, urea, hydroxylamine hydrochloride, hydroxylamine sulfate and cyclohexanol.

7. A method for preparing a hot melt adhesive, comprising a hot melt adhesive as claimed in claims 1 to 6, characterized in that: The method comprises the following preparation steps: S1. Raw material preparation: Prepare resin polymers, polyol polymers, POE polyolefin elastomers, waxes and additives; S2. Mixing and stirring: Put the resin polymer, polyol polymer, POE polyolefin elastomer and wax material into a stirring device and mix them evenly; S3, reaction synthesis: At a certain temperature and vacuum degree, dehydration reaction is carried out under auxiliary nitrogen protection; S4. Add auxiliary materials: After the reaction is completed, add the prepared auxiliary agent and continue stirring for 2 to 4 hours; S5. Final processing: The hot melt adhesive that has completed the reaction is cooled to room temperature for discharge and packaging.

8. A method for preparing a hot melt adhesive according to claim 7, characterized in that: In step S2, the stirring device is a stirring device with vacuum degassing function and temperature adjustment function.

9. A method for preparing a hot melt adhesive according to claim 7, characterized in that: In step S3, the stirring process is carried out in an environment where the vacuum degree is 0.01-0.05 MPa and the rotation speed is 400 r / min. The stirring temperature is a step-type temperature change environment, and nitrogen is added during the process. The details are as follows: The first stage is carried out at 40-50°C for 2-4 hours; In the second stage, the temperature is raised to 60-80°C for 1-2 hours; In the third stage, the temperature is raised to 100-130°C for 2-3 hours; In the fourth stage, the temperature is lowered to 70-75°C and nitrogen is introduced; The fifth stage is to heat to 80-100°C for 3-4 hours; In the sixth stage, the temperature is raised to 105-120°C for vacuum degassing for 0.5-1h.

10. A method for preparing hot melt adhesive according to claim 7, characterized in that: In step S5, the hot melt adhesive is cured before discharging and packaging.

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