Hot melt adhesive with high peel strength and method for its production

Abstract

The application relates to the technical field of hot melt adhesives, and discloses a hot melt adhesive with high peeling strength and a preparation method thereof, which comprises the following raw materials in proportion by weight: ethylene-vinyl acetate copolymer 35-55 parts by weight; polypropylene 20-35 parts by weight; petroleum resin 5-15 parts by weight; hydrogenated rosin resin 5-10 parts by weight; compatilizer 1-3 parts by weight; antioxidant 0.5-1 part by weight; ethylene-propylene-diene rubber 5-15 parts by weight; and reactive compatilizer 0.1-0.5 part by weight. The introduction of a proper amount of crystalline polymer polyethylene in the hot melt adhesive formula can improve the temperature resistance and anti-creep performance of the hot melt adhesive, thereby improving the peeling strength of the hot melt adhesive under high-temperature or high-stress conditions; the introduction of EPDM and the reactive compatilizer significantly improves the compatibility of EVA and PP, effectively prevents delamination, and improves the long-term stability of the hot melt adhesive.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot melt adhesives, and particularly relates to a hot melt adhesive with high peel strength and a preparation method thereof. BACKGROUND

[0002] As a kind of fast and efficient adhesive, hot melt adhesive is widely used in packaging, textile, electronics and other fields. Traditional hot melt adhesive is mainly based on amorphous polymers, such as ethylene-vinyl acetate copolymer (EVA), styrene block copolymer (SBS) and the like. These amorphous polymers endow hot melt adhesive with good flexibility and adhesion, so that it can quickly wet the surface of the adherend and form adhesion. However, the shortcomings of amorphous hot melt adhesive are increasingly prominent. First, its temperature resistance is poor, and it is easy to soften and creep under high temperature environment, resulting in a significant decrease in adhesion strength. For example, in the application of automotive interior, outdoor advertising and the like, adhesion failure under high temperature environment is a common problem. Second, the anti-creep performance of amorphous hot melt adhesive is insufficient, and it is easy to deform under long-term load, resulting in adhesion relaxation. For example, in the application of heavy packaging, structural adhesion and the like, the adhesion reliability under long-term load is crucial. In order to improve the temperature resistance and anti-creep performance of hot melt adhesive, a common strategy is to increase the molecular weight of the polymer. However, increasing the molecular weight will significantly increase the melt viscosity of hot melt adhesive, resulting in poor flowability and processability, which is difficult to meet the process requirements of rapid coating, spraying and the like. Therefore, how to improve the temperature resistance and anti-creep performance of hot melt adhesive without sacrificing flowability and processability is a technical problem to be solved. At present, some researches try to improve the performance of amorphous hot melt adhesive by adding fillers, crosslinking agents and the like. However, these methods often have problems such as poor dispersibility and difficult reaction control, which are difficult to achieve overall performance improvement. Therefore, it is of great research significance and application value to develop a new type of hot melt adhesive formula which can significantly improve the temperature resistance and anti-creep performance while ensuring the flowability and processability.

[0003] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0004] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a hot melt adhesive with high peel strength and a preparation method thereof, aiming to improve the temperature resistance and anti-creep performance of hot melt adhesive.

[0005] The technical scheme of the present application is as follows:

[0006] A hot melt adhesive with high peel strength, wherein the following raw materials are included in terms of weight fraction:

[0007] Ethylene-vinyl acetate copolymer: 35-55 parts by weight;

[0008] Polypropylene: 20-35 parts by weight;

[0009] Petroleum resin: 5-15 parts by weight;

[0010] Hydrogenated rosin resin: 5-10 parts by weight;

[0011] Compatibility agent: 1-3 parts by weight;

[0012] Antioxidant: 0.5-1 parts by weight;

[0013] Ethylene-propylene-diene rubber: 5-15 parts by weight;

[0014] Reactive compatibility agent: 0.1-0.5 parts by weight;

[0015] The compatibility agent is maleic anhydride grafted polypropylene, and the maleic anhydride grafting rate is 1-3%;

[0016] The reactive compatibility agent is epoxy vinyl siloxane.

[0017] The introduction of a proper amount of crystalline polymer polyethylene in the hot melt adhesive formula can improve the temperature resistance and creep resistance of the hot melt adhesive, thereby improving its peel strength under high temperature or high stress conditions. And a small amount of ethylene-propylene-diene rubber is introduced in the EVA / PP hot melt adhesive system. EPDM has good elasticity and weather resistance, which can improve the flexibility and impact resistance of the hot melt adhesive. At the same time, EPDM molecular chain contains a small amount of unsaturated double bonds, which can react with EVA and PP to improve the compatibility between the three, reduce the risk of delamination and separation. By using a reactive compatibility agent, stronger chemical bonding can be formed between EVA and PP, significantly improving compatibility, effectively preventing delamination, and improving the mechanical properties and stability of the hot melt adhesive.

[0018] The hot melt adhesive with high peel strength, wherein the ethylene-vinyl acetate copolymer EVA has a vinyl acetate content of 25-35% and a melt index of 2.8-3.2 g / 10 min.

[0019] The hot melt adhesive with high peel strength, wherein the polypropylene is a homopolymer polypropylene resin with a melt index of 3-8 g / 10 min.

[0020] The hot melt adhesive with high peel strength, wherein the petroleum resin is a C5 petroleum resin with a softening point of 90-120℃, and the hydrogenated rosin resin is a hydrogenated rosin resin with a softening point of 80-100℃.

[0021] The hot melt adhesive with high peel strength, wherein the antioxidant is antioxidant 1010 or antioxidant 1076.

[0022] The hot melt adhesive with high peel strength, wherein the ethylene content of the ethylene-propylene-diene rubber is 50-70%, and the diene content is 3-8%.

[0023] A preparation method of the hot melt adhesive with high peel strength as described above, comprising the following steps:

[0024] Raw material pretreatment: dry the ethylene-vinyl acetate copolymer at 70-90℃ for 3-5 hours, and dry the ethylene-propylene-diene rubber at 70-90℃ for 3-5 hours;

[0025] Melt blending: after the ethylene-vinyl acetate copolymer and the ethylene-propylene-diene rubber are completely melted, add the polypropylene through the second feeding port, then add the petroleum resin, the hydrogenated rosin resin, the compatibilizer and the antioxidant through the third feeding port, and continue to mix;

[0026] Sequential feeding: after the ethylene-vinyl acetate copolymer and the ethylene-propylene-diene rubber are completely melted, add the polypropylene through the second feeding port, then add the petroleum resin, the hydrogenated rosin resin, the compatibilizer and the antioxidant through the third feeding port, and continue to mix;

[0027] Reaction and homogenization: adjust the temperature of the extruder to 180-200℃, add the reactive compatibilizer through the fourth feeding port, and increase the screw speed to 300-400 rpm, so that the components are fully mixed and grafting reaction occurs;

[0028] Cooling: the uniformly mixed melt is extruded from the die into a rod shape, cooled to room temperature by a water cooling system, and cut into the required size.

[0029] Beneficial effects: the present application can improve the temperature resistance and creep resistance of the hot melt adhesive by introducing an appropriate amount of crystalline polymer polyethylene into the hot melt adhesive formula, thereby improving its peel strength under high temperature or high stress conditions. At the same time, the addition of the compatibilizer improves the compatibility of the crystalline polymer and the amorphous polymer, and improves the adhesion and flowability of the hot melt adhesive. Furthermore, the introduction of a small amount of ethylene-propylene-diene rubber in the EVA / PP hot melt adhesive system can improve the compatibility between EVA and PP through the blending or grafting reaction of the unsaturated double bonds in the EPDM molecular chain, thereby reducing the risk of delamination and separation. Moreover, the use of a reactive compatibilizer can form stronger chemical bonds between EVA and PP, significantly improve the compatibility, effectively prevent delamination, and improve the mechanical properties and stability of the hot melt adhesive. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present application, the present application lists the following embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations of the present application.

[0031] The present application also provides a hot melt adhesive with high peel strength, comprising the following raw materials in parts by weight:

[0032] Ethylene-vinyl acetate copolymer (EVA): 35-55 parts by weight;

[0033] Polypropylene (PP): 20-35 parts by weight;

[0034] Ethylene-propylene-diene rubber (EPDM): 5-15 parts by weight;

[0035] Petroleum resin: 5-15 parts by weight;

[0036] Hydrogenated rosin resin: 5-10 parts by weight;

[0037] Compatibilizer: 1-3 parts by weight;

[0038] Reactive compatibilizer: 0.1-0.5 parts by weight;

[0039] Antioxidant: 0.5-1 parts by weight.

[0040] The present formulation uses EVA as the base resin, providing good adhesion and flexibility. PP, as a crystalline polymer, is added to improve the temperature resistance and creep resistance of the hot melt adhesive, thereby improving its peel strength under high temperature or high stress conditions. At the same time, the addition of compatibilizers improves the compatibility of crystalline polymers and amorphous polymers, and improves the adhesion and flowability of the hot melt adhesive. EVA and PP are commercially available products, which are low in price and have good economic efficiency.

[0041] The compatibility of polypropylene and ethylene-vinyl acetate copolymer is limited, which may cause delamination and precipitation of the hot melt adhesive during use, especially in high temperature or high humidity environments, affecting the adhesion effect and long-term stability. In addition, although the addition of PP improves the temperature resistance, it may also cause the flexibility of the hot melt adhesive to decrease, which performs well when bonding hard materials, but is prone to cracking or debonding when bonding flexible materials or under bending and torsional stress. Therefore, in the embodiment of the present application, a small amount of ethylene-propylene-diene rubber is introduced into the EVA / PP hot melt adhesive system. EPDM has good elasticity and weather resistance, which can improve the flexibility and impact resistance of the hot melt adhesive. At the same time, EPDM molecular chain contains a small amount of unsaturated double bonds, which can react with EVA and PP through blending or grafting, improving the compatibility between the three, and reducing the risk of delamination and precipitation.

[0042] Maleic anhydride grafted polypropylene as a compatibilizer, although it can improve the compatibility of EVA and PP, but its grafting rate and molecular weight have a greater impact on the compatibility effect. Therefore, in the embodiment of the present application, epoxy vinyl siloxane is used as a reactive compatibilizer to react with EVA and PP in the extrusion process to generate copolymer in situ, thereby achieving better compatibility effect. By using a reactive compatibilizer, stronger chemical bonding can be formed between EVA and PP, significantly improving the compatibility, effectively preventing delamination, and improving the mechanical properties and stability of the hot melt adhesive. At the same time, since the reaction occurs in situ during the extrusion process, the problem of excessive MAH-g-PP dosage leading to high melt viscosity can be avoided, maintaining good flowability and processability.

[0043] The embodiment comprehensively considers factors such as compatibility, flexibility, and weather resistance, and optimizes the hot melt adhesive formula by introducing EPDM and a reactive compatibilizer. As a toughening phase, the unsaturated double bonds in the molecular chain of EPDM can react with EVA and PP through blending or grafting, improving the compatibility between the three, and reducing the risk of delamination and separation. At the same time, EPDM has good elasticity and weather resistance, which can improve the flexibility and impact resistance of the hot melt adhesive. Epoxy vinyl siloxane reacts with EVA and PP in the extrusion process to generate copolymer in situ, forming stronger chemical bonding between EVA and PP, significantly improving the compatibility, effectively preventing delamination, and improving the mechanical properties and stability of the hot melt adhesive. Specifically, the epoxy group can react with the carboxyl group in EVA to form an ester bond, and the vinyl group can undergo free radical addition reaction with the unsaturated bond in PP to form a copolymer. These chemical reactions form a firm connection between EVA and PP, improving the compatibility. MAH-g-PP still exists as an auxiliary compatibilizer to further improve the compatibility.

[0044] The ethylene-vinyl acetate copolymer (EVA) can have a vinyl acetate content of 25-35% and a melt index of 2.8-3.2 g / 10 min. In the embodiment of the present application, the ethylene-vinyl acetate copolymer has a vinyl acetate content of about 27% and a melt index of 3.0 g / 10 min, and Escorene UL00328 from ExxonMobil Corporation is used.

[0045] The polypropylene (PP) can be a homopolymer polypropylene resin with a melt index of 3-8 g / 10 min. In the embodiment of the present application, the polypropylene is a homopolymer polypropylene resin with a melt index of 3.0 g / 10 min, and T30S from China Petroleum Chemical Co., Ltd. is used. For polymers with similar structures, the melt index is inversely proportional to the molecular weight. The higher the melt index, the stronger the melt flowability of the polymer, and the lower the corresponding molecular weight.

[0046] The petroleum resin can be a C5 petroleum resin with a softening point of 90-120°C. In the embodiment of the present application, the softening point of the petroleum resin is 105°C±5°C, and Pu Yang Hengtai R5110 is used. As a tackifier, the petroleum resin can improve the wettability and bonding strength of the hot melt adhesive.

[0047] The hydrogenated rosin resin can be a hydrogenated rosin resin with a softening point of 80-100°C. In the embodiment of the present application, the softening point of the hydrogenated rosin resin is 95-100°C, and JS-100L from Guangdong Hongtai New Material Co., Ltd. is used.

[0048] Although the petroleum resin can improve the wettability and bonding strength of the hot melt adhesive, it is prone to volatilization or oxidation at high temperatures, which leads to a decline in the performance of the hot melt adhesive and the generation of irritating odor, affecting the use experience and environmental protection. In addition, the source of petroleum resin is limited, and the price fluctuates greatly, which is not conducive to reducing production costs and ensuring the stability of the supply chain. Therefore, in the present application, the combination of petroleum resin and hydrogenated rosin resin is used. The hydrogenated rosin resin has better heat resistance and weather resistance, is not prone to volatilization or oxidation, can improve the long-term stability of the hot melt adhesive, and reduce odor. At the same time, rosin resin is widely available and relatively stable in price, which is conducive to reducing production costs and ensuring the stability of the supply chain.

[0049] The compatibilizer is maleic anhydride grafted polypropylene, which can be polypropylene with a maleic anhydride grafting rate of 1-3%. In the embodiment of the present application, the maleic anhydride grafted polypropylene is polypropylene with a maleic anhydride grafting rate of 1-1.4%, and Fusabond P353 from DuPont Company is used. The role of the compatibilizer is to improve the compatibility of EVA and PP, prevent the agglomeration of PP in the EVA matrix, and thus improve the mechanical properties and stability of the hot melt adhesive. Maleic anhydride is grafted onto the PP chain, which produces chemical bonding force between the PP chain segment and the EVA chain segment, reduces the interfacial tension, and increases the compatibility.

[0050] The antioxidant can be antioxidant 1010 or antioxidant 1076. In the embodiment of the present application, the antioxidant is antioxidant 1010, and antioxidant 1010 from BASF Company is used. The role of the antioxidant is to prevent the oxidative degradation of the hot melt adhesive during processing and use, and to improve its service life.

[0051] The ethylene content of the ternary ethylene propylene rubber can be 50-70%, and the diene content can be 3-8%. In the embodiment of the present application, the ethylene content of the ternary ethylene propylene rubber is 63%, and the diene content is 8%, and Vistalon 8780 from ExxonMobil Company is used.

[0052] The reactive compatibilizer is epoxy vinyl siloxane. In the embodiment of the present application, the epoxy vinyl siloxane is Silquest A-186 from MiTiCo.

[0053] In the scheme, a preparation method of hot melt adhesive with high peel strength is also provided, comprising the following steps:

[0054] (1) Raw material pretreatment: dry EVA in a vacuum oven at 70-90°C for 3-5 hours to remove moisture and prevent bubbles from being generated during extrusion;

[0055] Dry EPDM in a vacuum oven at 70-90°C for 3-5 hours to remove moisture.

[0056] (2) Melt blending: add dried EVA and EPDM to a first feeding port of a twin-screw extruder, start the extruder, and melt EVA and EPDM.

[0057] Among them, the temperature of zone 1 is set to 100-120°C, the temperature of zones 2 to 5 is set to 150-170°C, and the screw speed is set to 150-250 rpm.

[0058] Add EPDM and EVA to the first feeding port, melt blend EVA and EPDM first, which can improve the compatibility of the two and promote the dispersion of subsequent PP.

[0059] (3) Sequential feeding: after EVA and EPDM are completely melted, add PP through a second feeding port, then add petroleum resin, hydrogenated rosin resin, compatibilizer and antioxidant through a third feeding port, and continue mixing.

[0060] Among them, PP is slowly added by controlling the feeding speed of PP to ensure that PP is uniformly dispersed in the EVA melt.

[0061] (4) Reaction and homogenization: adjust the temperature of the extruder to 180-200°C, add the reactive compatibilizer through a fourth feeding port, and increase the screw speed to 300-400 rpm to fully mix the components and induce grafting reaction.

[0062] In step (4), the reactive compatibilizer is added through the fourth feeding port. Increasing the temperature of the extruder and the screw speed can promote the reaction between the reactive compatibilizer and EVA and PP, in-situ generate copolymer, thereby improving the compatibility, and improving the mechanical properties and stability of the hot melt adhesive.

[0063] Preferably, a static mixer is installed at the end of the extruder to further improve the mixing uniformity and reduce the agglomeration of PP in the EVA matrix, thereby improving the mechanical properties and stability of the hot melt adhesive.

[0064] (5) Cooling: extrude the uniformly mixed melt into a rod shape from the die, cool it to room temperature through a water cooling system, and then cut it into hot melt adhesive rods of desired size.

[0065] (6) Packaging: The hot melt adhesive stick is classified and screened to remove unqualified products, and then packaged to obtain the finished product.

[0066] The application is further illustrated by specific examples below. Example 1:

[0067] The formula of the product is as follows:

[0068] Ethylene-vinyl acetate copolymer: 45 parts by weight (Escorene UL00328, ExxonMobil Corporation);

[0069] Polypropylene: 30 parts by weight (T30S, China Petroleum Chemical Corporation);

[0070] Ethylene-propylene-diene rubber (EPDM): 10 parts by weight (Vistalon 8780, ExxonMobil Corporation);

[0071] Petroleum resin: 7 parts by weight (R5110, Puyang Hengtai);

[0072] Hydrogenated rosin resin: 8 parts by weight (JS-100L, Guangdong Hongtai New Material Co., Ltd.);

[0073] Compatibilizer maleic anhydride grafted polypropylene: 2 parts by weight (Fusabond P353, DuPont);

[0074] Reactive compatibilizer epoxy vinyl siloxane: 0.3 parts by weight (Silquest A-186, Momentive Performance Materials Group);

[0075] Antioxidant 1010: 0.7 parts by weight (BASF).

[0076] The preparation method of the product is as follows:

[0077] 1. Dry EVA and EPDM in a vacuum oven at 80°C for 4 hours to remove moisture.

[0078] 2. Add the dried EVA and EPDM to the first feeding port of the twin-screw extruder, set the temperature of zone 1 to 100°C, the temperature of zones 2 to 5 to 150°C, and the screw speed to 200 rpm.

[0079] 3. After the EVA and EPDM are completely melted, slowly add PP through the second feeding port, and then add petroleum resin, hydrogenated rosin resin, compatibilizer, and antioxidant through the third feeding port, and continue to mix.

[0080] 4. Adjust the temperature of the extruder to 190°C, add the reactive compatibilizer through the fourth feeding port, and increase the screw speed to 400 rpm to fully mix the components.

[0081] 5. The homogeneous melt is extruded from the die into a rod shape and cooled to room temperature by a water cooling system.

[0082] 6. The rod is cut into the desired size to obtain the hot melt adhesive rod. Example 2:

[0083] The product formulation is as follows:

[0084] Ethylene-vinyl acetate copolymer: 40 parts by weight (Escorene UL00328, ExxonMobil Corporation);

[0085] Polypropylene: 35 parts by weight (T30S, China Petroleum Chemical Co., Ltd.);

[0086] Ethylene-propylene-diene rubber (EPDM): 12 parts by weight (Vistalon 8780, ExxonMobil Corporation);

[0087] Petroleum resin: 5 parts by weight (R5110, Puyang Hengtai);

[0088] Hydrogenated rosin resin: 7 parts by weight (JS-100L, Guangdong Hongtai New Material Co., Ltd.);

[0089] Compatibilizer maleic anhydride grafted polypropylene: 1.5 parts by weight (Fusabond P353, DuPont);

[0090] Reactive compatibilizer epoxy vinyl siloxane: 0.4 parts by weight (Silquest A-186, Momentive Performance Materials Group);

[0091] Antioxidant 1010: 0.6 parts by weight (BASF Corporation).

[0092] The product preparation method is the same as Example 1.

[0093] Comparative Example 1:

[0094] The product formulation is as follows:

[0095] Ethylene-vinyl acetate copolymer: 50 parts by weight (Escorene UL00328, ExxonMobil Corporation);

[0096] Polypropylene: 30 parts by weight (T30S, China Petroleum Chemical Co., Ltd.);

[0097] Petroleum resin: 7 parts by weight (R5110, Puyang Hengtai);

[0098] Hydrogenated rosin resin: 8 parts by weight (JS-100L, Guangdong Hongtai New Material Co., Ltd.);

[0099] Compatibilizer maleic anhydride grafted polypropylene: 3 parts by weight (Fusabond P353, DuPont);

[0100] Antioxidant 1010: 0.7 parts by weight (BASF).

[0101] The product was prepared as follows:

[0102] 1. Dry the EVA in a vacuum oven at 80°C for 4 hours to remove moisture.

[0103] 2. Add the dried EVA to the first feeding port of the twin-screw extruder, set the temperature of zone 1 to 120°C, the temperature of zones 2 to 5 to 160°C, and the screw speed to 200 rpm.

[0104] 3. After the EVA is completely melted, slowly add the PP through the second feeding port, and then add the petroleum resin, hydrogenated rosin resin, compatibilizer, and antioxidant through the third feeding port, and continue to mix.

[0105] 4. Adjust the temperature of the extruder to 180°C, and increase the screw speed to 300 rpm, so that the components are fully mixed.

[0106] 5. Extrude the uniformly mixed melt from the die into a rod shape, and cool it to room temperature through a water cooling system.

[0107] 6. Cut it to the desired size to obtain a hot melt adhesive rod.

[0108] Comparative Example 2:

[0109] The product formula is as follows:

[0110] Ethylene-vinyl acetate copolymer: 55 parts by weight (Escorene UL00328, ExxonMobil);

[0111] Polypropylene: 20 parts by weight (T30S, China Petroleum Chemical Co., Ltd.);

[0112] Petroleum resin: 5 parts by weight (R5110, Puyang Hengtai);

[0113] Hydrogenated rosin resin: 7 parts by weight (JS-100L, Guangdong Hongtai New Material Co., Ltd.);

[0114] Compatibilizer maleic anhydride grafted polypropylene: 2 parts by weight (Fusabond P353, DuPont);

[0115] Antioxidant 1010: 1 part by weight (BASF).

[0116] The product was prepared in the same way as in Comparative Example 1.

[0117] Comparative Example 3:

[0118] A certain brand of EVA hot melt adhesive (hereinafter referred to as "control example") was selected for performance testing.

[0119] The products prepared in Examples 1-2 and Comparative Examples 1-3 were subjected to performance testing, and the performance testing methods were as follows:

[0120] The melt index was determined according to GB / T 3682.1-2018, with a test temperature of 190℃ and a load of 2.16 kg;

[0121] The softening point was determined according to GB / T 15332-2014;

[0122] The 180° peel strength was determined according to GB / T 2790-1995, with a substrate of corrugated paperboard and a test speed of 100 mm / min;

[0123] The shear strength was determined according to GB / T 7124-2008, with a substrate of corrugated paperboard;

[0124] The heat resistance was determined according to ASTM D4498-00, by maintaining at 70℃ or 80℃ for 24 hours, respectively, and observing whether there was softening or flow phenomenon;

[0125] The tensile strength was determined according to GB / T 1040.1-2018, with a test speed of 50 mm / min;

[0126] The elongation at break was determined according to GB / T 1040.1-2018, with a test speed of 50 mm / min.

[0127] The performance test results of Examples 1-2 and Comparative Examples 1-3 are shown in Table 1.

[0128] Table 1

[0129] Melt index Softening point 180° peel strength Shear strength Heat resistance Tensile strength Elongation at break Example 1 28 g / 10 min 105℃ 10 N / cm 1.0 MPa No significant change at 70°C and 80°C 12 MPa 400% Example 2 23 g / 10 min 110℃ 11 N / cm 1.1 MPa No significant change at 70°C and 80°C 13 MPa 450% Comparative Example 1 25 g / 10 min 95℃ 8 N / cm 0.8 MPa No significant change at 70°C 9 MPa 310% Comparative Example 2 30 g / 10 min 90℃ 7 N / cm 0.7 MPa No significant change at 70°C 10 MPa 340% Comparative Example 3 35 g / 10 min 85℃ 6 N / cm 0.6 MPa Slight softening at 70°C - -

[0130] Compared with Comparative Example 1-2 (without adding EPDM and reactive compatibilizer), the embodiment scheme of the present application has the following advantages:

[0131] 1. Better compatibility: The introduction of EPDM and reactive compatibilizer significantly improves the compatibility of EVA and PP, effectively prevents delamination, and improves the long-term stability of the hot melt adhesive.

[0132] 2. Higher flexibility and impact resistance: The addition of EPDM improves the flexibility and impact resistance of the hot melt adhesive, making it perform better in bonding flexible materials or in situations where bending and torsional stress is encountered.

[0133] 3. Higher mechanical properties: The introduction of reactive compatibilizers improves the chemical bonding between EVA and PP, increasing the tensile strength and elongation at break of the hot melt adhesive.

[0134] 4. Better overall performance: This embodiment takes into account factors such as compatibility, flexibility, weather resistance, and environmental friendliness, achieving a comprehensive improvement in the performance of the hot melt adhesive. The peel strength, shear strength, temperature resistance, and long-term stability are all expected to be significantly improved.

[0135] Compared with Comparative Example 3 (traditional EVA hot melt adhesive), the embodiment of the present application has the following advantages:

[0136] 1. Higher temperature resistance: The addition of PP increases the melting point of the hot melt adhesive, allowing it to maintain good bonding strength at higher temperatures.

[0137] 2. Better creep resistance: The crystallinity of PP gives the hot melt adhesive better creep resistance, making it less likely to deform under long-term load.

[0138] 3. Good flowability and processability: By controlling the molecular weight and content of PP and adding compatibilizers, the hot melt adhesive can have good flowability and processability, meeting the requirements of rapid coating, spraying, and other processes.

[0139] Through the comparison of the above examples and control examples, it can be seen that the hot melt adhesive formula provided by the present application effectively improves the temperature resistance, mechanical properties, and long-term stability of the hot melt adhesive by introducing PP, EPDM, hydrogenated rosin resin, and reactive compatibilizers. The performance indicators are all better than existing commercially available EVA hot melt adhesive products.

[0140] It should be understood that the application of the present application is not limited to the above examples, and those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should be within the scope of protection of the present application.

Claims

1. A hot melt adhesive having high peel strength, characterized in that, The following raw materials are included by weight: Ethylene-vinyl acetate copolymer: 35-55 parts by weight; Polypropylene: 20-35 parts by weight; Petroleum resin: 5-15 parts by weight; Hydrogenated rosin resin: 5-10 parts by weight; Compatibilizer: 1-3 parts by weight; Antioxidant: 0.5-1 parts by weight; Ethylene-propylene-diene rubber: 5-15 parts by weight; Reactive compatibilizer: 0.1-0.5 parts by weight; The compatibilizer is maleic anhydride grafted polypropylene with a grafting rate of 1-3%; The reactive compatibilizer is Silquest A-186 from MEGATUO High New Material Group; The ethylene content of the ethylene-propylene-diene rubber is 50-70%, and the diene content is 3-8%; The ethylene-vinyl acetate copolymer has a vinyl acetate content of 25-35% and a melt index of 2.8-3.2 g / 10 min; The polypropylene is a homopolymer polypropylene resin with a melt index of 3-8 g / 10 min.

2. The hot melt adhesive with high peel strength according to claim 1, characterized in that, The petroleum resin is a C5 petroleum resin with a softening point of 90-120°C, and the hydrogenated rosin resin is a hydrogenated rosin resin with a softening point of 80-100°C.

3. The hot melt adhesive with high peel strength according to claim 1, characterized in that, The antioxidant is antioxidant 1010 or antioxidant 1076.

4. A process for producing a hot-melt adhesive having high peel strength as claimed in any one of claims 1 to 3, characterized in that, The following steps are included: Raw material pretreatment: dry the ethylene-vinyl acetate copolymer at 70-90°C for 3-5 hours, and dry the ethylene-propylene-diene rubber at 70-90°C for 3-5 hours; Melt blending: add the dried ethylene-vinyl acetate copolymer and ethylene-propylene-diene rubber to the first feeding port of the twin-screw extruder, start the extruder, melt the ethylene-vinyl acetate copolymer and ethylene-propylene-diene rubber, set the temperature of zone 1 to 100-120°C, the temperature of zones 2-5 to 150-170°C, and the screw speed to 150-250 rpm; Sequential feeding: after the ethylene-vinyl acetate copolymer and ethylene-propylene-diene rubber are completely melted, add the polypropylene through the second feeding port, then add the petroleum resin, hydrogenated rosin resin, compatibilizer, and antioxidant through the third feeding port, and continue mixing; Reaction and homogenization: adjust the temperature of the extruder to 180-200°C, add the reactive compatibilizer through the fourth feeding port, increase the screw speed to 300-400 rpm, and fully mix and graft the components; Cooling: extrude the uniformly mixed melt into a rod shape from the die, cool it to room temperature through the water cooling system, and cut it into the desired size.