Hot melt adhesive with high cohesion and preparation method thereof

Abstract

The invention discloses a hot melt adhesive with high cohesion and a preparation method thereof, and relates to the technical field of hot melt adhesives. The invention relates to a hot melt adhesive with high cohesion, which comprises 50-64 parts of matrix resin, 18-24 parts of tackifying resin, 3.2-4.5 parts of polyethylene wax, 1.5-2.4 parts of biological wax material, 10-16 parts of modified starch particles, 1.2-3.2 parts of maleic anhydride grafted polyethylene and 0.8-1.2 parts of antioxidant, the matrix resin comprises maleic anhydride grafted APAO resin and PHBV resin, and the tackifying resin comprises maleic anhydride grafted APAO resin and PHBV resin. The tackifying resin comprises C5 hydrogenated petroleum resin and rosin polyol ester, and the biological wax material comprises any one of soybean wax, beeswax or palm wax. The maleic anhydride grafted APAO resin and the PHBV resin are used as matrix resins, and a plurality of bio-based assistants are matched, so that the degradation efficiency of the hot melt adhesive is greatly improved, the hot melt adhesive can be fully degraded or hydrolyzed by microorganisms in the environment after being discarded, and the hot melt adhesive has certain environmental protection property.

Description

Technical Field

[0001] The invention relates to the technical field of hot melt adhesives, and in particular to a hot melt adhesive with high cohesive force and a preparation method thereof. Background Art

[0002] Hot melt adhesive is a plastic adhesive. Its physical state changes with temperature within a certain temperature range, while its chemical properties remain unchanged. It is non-toxic and odorless, and is an environmentally friendly chemical product. It can be used to stick solids such as wood, plastic, fiber, fabric, metal, furniture, lampshades, leather, handicrafts, toys, electronics, electrical components, paper products, ceramics, and pearl cotton packaging. It is used in large quantities and is widely used.

[0003] However, due to its structural characteristics, conventional hot melt adhesives are highly resistant to microorganisms and are difficult to be fully degraded or hydrolyzed by microorganisms in the environment. As a result, hot melt adhesives will remain in the environment for a long time after being discarded, causing increasingly prominent environmental problems. Therefore, the production of environmentally friendly hot melt adhesives with good bonding effects and biodegradability has become an important development direction for the adhesive industry. Summary of the invention

[0004] In order to enable the hot melt adhesive to be fully degraded or hydrolyzed by microorganisms in the environment and improve the environmental friendliness of the hot melt adhesive, the present application provides a hot melt adhesive with high cohesion and a preparation method thereof.

[0005] In the first aspect, the present application provides a hot melt adhesive with high cohesion using the following technical solution: A hot melt adhesive with high cohesion, comprising the following raw materials in parts by weight: Base resin: 50-64 parts; Tackifying resin: 18-24 parts; Polyethylene wax: 3.2-4.5 parts; Biological wax: 1.5-2.4 parts; Modified starch granules: 10-16 parts; Maleic anhydride grafted polyethylene: 1.2-3.2 parts; Antioxidant: 0.8-1.2 parts; The base resin comprises a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1: (0.6-1.5), the tackifying resin comprises a mixture of C5 hydrogenated petroleum resin and rosin polyol ester in a weight ratio of 1: (2-5), the modified starch particles are thermoplastic starch modified by plasticization, and the biowax comprises any one of soybean wax, beeswax or palm wax.

[0006] By adopting the above technical scheme, using maleic anhydride grafted APAO resin and PHBV resin as the base resin, and combining with a variety of bio-based additives, the prepared hot melt adhesive not only has good bonding properties, but also has good degradability and high degradation efficiency. Therefore, the hot melt adhesive can be fully degraded or hydrolyzed by microorganisms in the environment after being discarded, which is beneficial to improving the environmental protection of the hot melt adhesive.

[0007] Optionally, the preparation method of the maleic anhydride grafted APAO resin comprises the following steps: A1. First, maleic anhydride and dicumyl peroxide are fully mixed in a weight ratio of 1:(0.05-0.075), and completely dissolved in acetone as a solvent to obtain a maleic anhydride modified liquid; A2. Add the maleic anhydride modified liquid obtained in step A1 to the APAO resin, wherein the weight ratio of the maleic anhydride to the APAO resin is 1:(25-30), then heat to 180-200°C and stir thoroughly, and then extrude and cool to granulate to obtain the maleic anhydride grafted APAO resin.

[0008] By adopting the above technical solution, it is beneficial to prepare maleic anhydride grafted APAO resin with a certain grafting rate, so that it can be used in the field of hot melt adhesives and can be fully compatible and mixed with PHBV resin. Secondly, using maleic anhydride grafted modified APAO resin can also improve the adhesion of hot melt adhesives with APAO as the matrix resin to the surface of polar materials, which is beneficial to improve the versatility of hot melt adhesives and expand the application range of hot melt adhesives.

[0009] Optionally, the HV content in the PHBV resin is 9%-16% (mol).

[0010] The adoption of the above technical solution is beneficial to improving the cohesive strength and degradation efficiency of the matrix resin, thereby improving the bonding strength and degradation performance of the hot melt adhesive.

[0011] Optionally, the rosin polyol ester is one of rosin glycerol ester and rosin pentaerythritol ester.

[0012] By adopting the above technical scheme, rosin glycerol ester and rosin pentaerythritol ester are both alcohol esterified modified rosin resins, which can not only be used as tackifying resins to improve the bonding properties of hot melt adhesives, but also have good biodegradability, which is beneficial to improving the degradation properties of hot melt adhesives and improving the degradation efficiency of hot melt adhesives.

[0013] Optionally, the rosin polyol ester is rosin pentaerythritol ester, and the C5 hydrogenated petroleum resin and the rosin pentaerythritol ester are mixed in a weight ratio of 1:(2-3).

[0014] By adopting the above technical solution, rosin pentaerythritol ester has higher molecular weight and thermal stability than rosin glycerol ester, which is beneficial to improve the cohesive strength and bonding performance of hot melt adhesive, and can provide better comprehensive performance for hot melt adhesive. Moreover, the amount of rosin pentaerythritol ester required is small, and more low-cost C5 hydrogenated petroleum resin can be added to the tackifying resin, which is beneficial to reduce the preparation cost of hot melt adhesive.

[0015] Optionally, the biological wax material is beeswax.

[0016] By adopting the above technical solution, beeswax has good viscosity, adhesion and hardness, and the hardness is moderate, which is beneficial to improving the cohesive strength of the hot melt adhesive and further improving the bonding performance of the hot melt adhesive.

[0017] Optionally, the plasticization modification of the modified starch particles comprises the following steps: First, corn starch and water are fully mixed at a ratio of 1:1, and then a composite plasticizer composed of glycerol, formamide and urea is added. The mixture is kept at room temperature and fully stirred at a speed of 3000-3500r / min, and then allowed to stand for 24-48 hours. The modified starch particles are obtained by extrusion and cooling.

[0018] By adopting the above technical scheme, corn starch is modified by using a composite plasticizer made of a mixture of glycerol, formamide and urea, so that corn starch can be modified into a thermoplastic starch, thereby effectively improving the melting point of the modified starch particles and imparting a certain thermoplasticity, which is conducive to making the modified starch particles suitable for high-temperature hot melt adhesive systems and not easily gelatinized due to high temperature.

[0019] Optionally, in the composite plasticizer, the mixing weight ratio of the glycerol, the formamide and the urea is 1:(0.4-0.6):(0.4-0.6), and the mixing weight ratio of the corn starch to the composite plasticizer is 1:(0.2-0.25).

[0020] By adopting the above technical scheme, when the mixing weight ratio of glycerol, formamide and urea is within the range of 1:(0.4-0.6):(0.4-0.6) and the mixing weight ratio of corn starch and composite plasticizer is within the range of 1:(0.2-0.25), the composite plasticizer can fully plasticize and modify the corn starch, thereby facilitating the acquisition of modified starch particles suitable for use in hot melt adhesives.

[0021] Optionally, the antioxidant is selected from antioxidant 1010 and antioxidant 168 mixed in a weight ratio of 1:(2-3).

[0022] By adopting the above technical solution, a certain synergistic effect can be produced between the antioxidant 1010 and the antioxidant 168, which is beneficial to improving the antioxidant property of the hot melt adhesive and preventing the hot melt adhesive from turning yellow or reducing its viscosity due to oxidation after being placed for a long time.

[0023] In a second aspect, the present application provides a method for preparing a hot melt adhesive with high cohesion using the following technical solution: A method for preparing a hot melt adhesive with high cohesion comprises the following steps: S1, firstly, 10% of the base resin is fully mixed with polyethylene wax, biowax, maleic anhydride grafted polyethylene and antioxidant at a mixing temperature of 160-175° C., and then the remaining base resin is added, and the mixture is fully stirred to obtain a first mixture; S2, lowering the mixing temperature to 140-150° C., then adding the tackifying resin and the modified starch granules, and continuing stirring for 20-30 minutes to obtain a second mixture; S3, subjecting the second mixture to vacuum exhaust treatment, and then melting and extruding the second mixture, and rapidly drawing it to a circulating cooling water tank with a cooling solution temperature not higher than 5° C. for cooling, and then cutting and drying, thereby obtaining a hot melt adhesive with high cohesive force.

[0024] By adopting the above technical solution, the mixing temperature is lowered when mixing the tackifying resin and the modified starch particles, which is beneficial to reducing the impact of high-temperature melt mixing on the tackifying resin and the modified starch particles, preventing the tackifying resin from yellowing and the modified starch particles from gelatinizing at high temperature, and improving the appearance performance of the hot melt adhesive; and quickly cooling the hot melt adhesive after extrusion can not only quickly shape the hot melt adhesive, but also prevent the hot melt adhesive from crystallizing, thereby reducing the impact on the transparency and other properties of the product. Secondly, the preparation method of the degradable hot melt adhesive is simple, which is conducive to subsequent mass production.

[0025] In summary, the technical solution of this application has at least one of the following beneficial effects: 1. By using maleic anhydride grafted APAO resin and PHBV resin as the base resin and combining with a variety of bio-based additives, the degradation efficiency of the hot melt adhesive is greatly improved, which is conducive to the hot melt adhesive being fully degraded or hydrolyzed by microorganisms in the environment after being discarded, and has a certain degree of environmental protection. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in combination with preparation examples, embodiments and comparative examples.

[0027] Preparation Example [Preparation Example 1-1] A maleic anhydride grafted APAO resin comprises the following preparation steps: A1. First, 2 kg of maleic anhydride and 0.1 kg of dicumyl peroxide were fully mixed and completely dissolved with acetone as a solvent to obtain a maleic anhydride modified liquid; A2. Add the maleic anhydride modified liquid obtained in step A1 into 50 kg of APAO resin, then heat to 180° C. and stir thoroughly, and then extrude and cool to granulate to obtain maleic anhydride grafted APAO resin.

[0028] In this preparation example, the APAO resin selected is Evonik APAO 888, and the softening point of this grade of APAO resin is 160°C.

[0029] [Preparation Example 1-2] A maleic anhydride grafted APAO resin comprises the following preparation steps: A1. First, 2 kg of maleic anhydride and 0.15 kg of dicumyl peroxide were fully mixed and completely dissolved with acetone as a solvent to obtain a maleic anhydride modified liquid; A2. Add the maleic anhydride modified liquid obtained in step A1 into 60 kg of APAO resin, then heat to 200° C. and stir thoroughly, and then extrude and cool to granulate to obtain maleic anhydride grafted APAO resin.

[0030] In this preparation example, the APAO resin selected is Evonik APAO 888, and the softening point of this grade of APAO resin is 160°C.

[0031] [Preparation Example 2-1] A modified starch granule comprises the following preparation steps: First, 20 kg of corn starch and 20 kg of water were fully stirred, and then a composite plasticizer consisting of 5 kg of glycerol, 0.25 kg of formamide and 0.25 kg of urea was added, and the mixture was fully stirred at a speed of 3000 r / min for 20 minutes, and then allowed to stand for 24 hours, and then extruded and cooled to granulate to obtain modified starch granules.

[0032] [Preparation Example 2-2] A modified starch granule comprises the following preparation steps: First, 20 kg of corn starch and 20 kg of water were fully stirred, and then a composite plasticizer composed of 4 kg of glycerol, 0.16 kg of formamide and 0.16 kg of urea was added, and the mixture was fully stirred at a speed of 3500 r / min for 20 minutes, and then allowed to stand for 48 hours, and then extruded and cooled to granulate to obtain modified starch granules. Example

[0033] [Example 1] A hot melt adhesive with high cohesion comprises the following raw materials: 50 kg of base resin, 24 kg of tackifying resin, 3.2 kg of polyethylene wax, 2.4 kg of biological wax, 16 kg of modified starch particles, 3.2 kg of maleic anhydride grafted polyethylene, 0.4 kg of antioxidant 1010 and 0.8 kg of antioxidant 168.

[0034] In this embodiment, the base resin is a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1:1, that is, the addition amount of maleic anhydride grafted APAO resin is 25kg, and the addition amount of PHBV resin is 25kg. Specifically, the maleic anhydride grafted APAO resin is a maleic anhydride grafted APAO resin prepared in [Preparation Example 1-1], and the PHBV resin is a PHBV resin with an HV content of 9%.

[0035] In this embodiment, the tackifying resin is a mixture of C5 hydrogenated petroleum resin and rosin glycerol ester in a ratio of 1:2, that is, the added amount of C5 hydrogenated petroleum resin is 8 kg, and the added amount of rosin glycerol ester is 16 kg.

[0036] In this embodiment, the biological wax material is soybean wax, and the modified starch particles are modified starch particles prepared in [Preparation Example 2-1].

[0037] A method for preparing a hot melt adhesive with high cohesion comprises the following steps: S1, firstly, 10% of the base resin is fully mixed with polyethylene wax, biowax, maleic anhydride grafted polyethylene and antioxidant at a mixing temperature of 160° C., and then the remaining base resin is added, and the mixture is fully stirred to obtain a first mixture; S2, lowering the mixing temperature to 140° C., then adding the tackifying resin and the modified starch granules, and continuing stirring for 20 minutes to obtain a second mixture; S3, subjecting the second mixture to vacuum exhaust treatment, and then melting and extruding the second mixture, and rapidly drawing it to a circulating cooling water tank with a cooling solution temperature of 5° C. for cooling, and then cutting and drying, thereby obtaining a hot melt adhesive with high cohesive force.

[0038] The cooling solution includes 10% anti-adhesive liquid and 90% deionized water.

[0039] [Example 2] A hot melt adhesive with high cohesion, comprising the following raw materials: 64kg base resin, 18kg tackifying resin, 4.5kg polyethylene wax, 1.5kg biowax, 10kg modified starch granules, 1.2 kg maleic anhydride grafted polyethylene, 0.2 kg antioxidant 1010 and 0.6 kg antioxidant 168.

[0040] In this embodiment, the base resin is a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1:1.5, that is, the addition amount of maleic anhydride grafted APAO resin is 25.6 kg, and the addition amount of PHBV resin is 38.4 kg. Specifically, the maleic anhydride grafted APAO resin is a maleic anhydride grafted APAO resin prepared in [Preparation Example 1-2], and the PHBV resin is a PHBV resin with an HV content of 16%.

[0041] In this embodiment, the tackifying resin is a mixture of C5 hydrogenated petroleum resin and rosin glycerol ester in a ratio of 1:2, that is, the added amount of C5 hydrogenated petroleum resin is 8 kg, and the added amount of rosin glycerol ester is 16 kg.

[0042] In this embodiment, the biological wax material is soybean wax, and the modified starch particles are modified starch particles prepared in [Preparation Example 2-2].

[0043] A method for preparing a hot melt adhesive with high cohesion comprises the following steps: S1, firstly, 10% of the base resin is fully mixed with polyethylene wax, biowax, maleic anhydride grafted polyethylene and antioxidant at a mixing temperature of 175° C., and then the remaining base resin is added, and the mixture is fully stirred to obtain a first mixture; S2, lowering the mixing temperature to 150° C., then adding the tackifying resin and the modified starch granules, and continuing stirring for 30 minutes to obtain a second mixture; S3, subjecting the second mixture to vacuum exhaust treatment, and then melting and extruding the second mixture, and rapidly drawing it to a circulating cooling water tank with a cooling solution temperature of 5° C. for cooling, and then cutting and drying, thereby obtaining a hot melt adhesive with high cohesive force.

[0044] The cooling solution includes 10% anti-adhesive liquid and 90% deionized water.

[0045] [Example 3] A hot melt adhesive with high cohesion, which differs from [Example 1] in that the proportions of maleic anhydride grafted APAO resin and PHBV resin in the base resin are different.

[0046] In this embodiment, the base resin is a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1:0.6, that is, the addition amount of maleic anhydride grafted APAO resin is 31.25 kg, and the addition amount of PHBV resin is 18.75 kg.

[0047] [Example 4] A hot melt adhesive with high cohesion, which differs from [Example 1] in that the proportions of maleic anhydride grafted APAO resin and PHBV resin in the base resin are different.

[0048] In this embodiment, the base resin is a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1:1.5, that is, the addition amount of maleic anhydride grafted APAO resin is 20 kg, and the addition amount of PHBV resin is 30 kg.

[0049] [Example 5] A hot melt adhesive with high cohesion, which is different from [Example 1] in that the PHBV resin in the base resin is different.

[0050] In this embodiment, the PHBV resin is a PHBV resin with an HV content of 12%.

[0051] [Example 6] A hot melt adhesive with high cohesion, which is different from [Example 1] in that the PHBV resin in the base resin is different.

[0052] In this embodiment, the PHBV resin is a PHBV resin with an HV content of 16%.

[0053] [Example 7] A hot melt adhesive with high cohesion, which differs from [Example 6] in that the tackifying resin is different.

[0054] In this embodiment, the tackifying resin is a mixture of C5 hydrogenated petroleum resin and rosin glycerol ester in a ratio of 1:5, that is, the added amount of C5 hydrogenated petroleum resin is 4 kg, and the added amount of rosin glycerol ester is 20 kg.

[0055] [Example 8] A hot melt adhesive with high cohesion, which differs from [Example 6] in that the tackifying resin is different.

[0056] In this embodiment, the tackifying resin is a mixture of C5 hydrogenated petroleum resin and rosin pentaerythritol ester in a ratio of 1:2, that is, the added amount of C5 hydrogenated petroleum resin is 8 kg, and the added amount of rosin pentaerythritol ester is 16 kg.

[0057] [Example 9] A hot melt adhesive with high cohesion, which differs from [Example 6] in that the tackifying resin is different.

[0058] In this embodiment, the tackifying resin is a mixture of C5 hydrogenated petroleum resin and rosin pentaerythritol ester in a ratio of 1:3, that is, the added amount of C5 hydrogenated petroleum resin is 6 kg, and the added amount of rosin pentaerythritol ester is 18 kg.

[0059] [Example 10] A hot melt adhesive with high cohesion, which is different from [Implementation 9] in that the biological wax is different.

[0060] In this embodiment, the biological wax material is replaced by beeswax in equal amounts.

[0061] [Example 11] A hot melt adhesive with high cohesion, which is different from [Example 9] in that the biological wax is different.

[0062] In this example, the biowax was replaced by palm wax in equal amounts.

[0063] Comparative Example [Comparative Example 1] A hot melt adhesive is selected from the common EVA system plate edge sealing hot melt adhesive on the market, and specifically Henkel KS3925 edge sealing hot melt adhesive is selected.

[0064] [Comparative Example 2] A hot melt adhesive, which differs from [Example 1] in that the base resin is different.

[0065] In this comparative example, the PHBV resin in the base resin is replaced by an equal amount of maleic anhydride grafted APAO resin.

[0066] [Comparative Example 3] A hot melt adhesive, which differs from [Example 1] in that no biological wax is added.

[0067] In this comparative example, the biowax was replaced by PE wax in equal amounts.

[0068] [Comparative Example 4] A hot melt adhesive, which differs from [Example 1] in that modified starch particles are not added.

[0069] In this comparative example, the modified starch granules were replaced by corn starch in equal amounts.

[0070] Performance test data 1. Degradation performance test: The hot melt adhesives prepared in each embodiment and comparative example were uniformly coated on release paper, and pressed into hot melt adhesive sheets with a thickness of 0.3 mm by a hot press, and then placed in an environmental box with an ambient temperature of 25°C and a humidity of 50%Rh for full curing for 72 hours. The sheets were uniformly cut into 50mm×50mm sizes and weighed, and then buried in the same piece of moist soil with a burial depth of 100mm. The soil was dug out regularly, thoroughly cleaned and dried, and then weighed. The remaining mass percentage (%) of the hot melt adhesive sheet was calculated and recorded.

[0071] 2. Bond strength test: The test was carried out with reference to GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material), wherein PP board and pine board were selected as bonding materials, and the tensile shear strength (MPa) and bonding failure type of the hot melt adhesive prepared in each embodiment and comparative example were recorded.

[0072] Table 1 Degradation performance test data of hot melt adhesive Table 2 Adhesive performance test data of hot melt adhesive Combining Example 1 with Comparative Example 1 and the data in Tables 1 and 2, it can be seen that compared with conventional EVA edge-sealing hot melt adhesives, the hot melt adhesive prepared in Example 1 using maleic anhydride grafted APAO resin and PHBV resin as base resins and combined with a variety of bio-based additives exhibits excellent degradability and bonding properties. It not only has a high degradation efficiency in the natural environment and can be degraded to less than 40% of the original mass within 360 days, but also has good bonding strength when used for non-polar materials and polar materials, and has good compatibility.

[0073] Combining Example 1 with Comparative Example 2, Examples 3-6 and the data in Tables 1 and 2, it can be seen that by using PHBV resin with good biodegradability to replace part of the maleic anhydride grafted APAO resin as the base resin, the prepared hot melt adhesive exhibits good degradability and high degradation efficiency, and as the proportion of PHBV resin in the base resin gradually increases, the degradation efficiency of the prepared hot melt adhesive gradually increases, but the bonding strength shows a trend of gradually decreasing. This may be because PHBV resin is a bio-based biodegradable polyester, which has better biodegradability and biocompatibility than maleic anhydride grafted APAO resin. Therefore, as the proportion of PHBV resin in the base resin increases, the base resin degrades faster in the soil. However, due to the low bonding performance of the PHBV resin itself, after mixing with the maleic anhydride grafted APAO resin, it will directly affect the bonding properties of the base resin, thereby reducing the bonding strength of the hot melt adhesive to various materials.

[0074] Secondly, as the HV (hydroxyvaleric acid) content in the PHBV resin increases, the bonding strength of the hot melt adhesive increases significantly, and the degradation efficiency of the hot melt adhesive also increases slightly. This may be because the HV segment plays the role of a soft segment in PHBV, and as the HV content increases, the soft segment may interfere with the orderly arrangement of the PHBV resin molecular segments, causing the crystallinity of the PHBV resin to decrease, thereby increasing the elastic modulus, breaking stress and degradability of the PHBV resin, which is beneficial to improving the cohesive strength and degradation efficiency of the matrix resin, and improving the bonding strength and degradation performance of the hot melt adhesive.

[0075] Combining Examples 6-9 and the data in Tables 1 and 2, it can be seen that as the proportion of rosin glycerol ester in the tackifying resin increases, the degradation efficiency and bonding strength of the hot melt adhesive are slightly improved, and when the rosin glycerol ester in the tackifying resin is replaced by rosin pentaerythritol ester in equal amounts, the degradation efficiency and bonding strength of the hot melt adhesive are also improved, and when the tackifying resin is C5 hydrogenated petroleum resin and rosin pentaerythritol ester mixed at 1:3 parts by weight, it has better degradation performance and bonding performance than the tackifying resin is C5 hydrogenated petroleum resin and rosin glycerol ester mixed at 1:5 parts by weight. This may be because both rosin glycerol ester and rosin pentaerythritol ester belong to alcohol esterified modified rosin resin, and rosin resin belongs to natural polymer, which has good biodegradability itself. After being modified by alcohol esterification, it is more suitable for hot melt adhesive system, and as the proportion of rosin glycerol ester or rosin pentaerythritol ester in the tackifying resin increases, the degradation performance of the hot melt adhesive can naturally be improved to a certain extent. Compared with rosin glycerol ester, rosin pentaerythritol ester has higher molecular weight and thermal stability, which is beneficial to improve the cohesive strength and bonding performance of hot melt adhesive and can provide better comprehensive performance for hot melt adhesive.

[0076] Combining Examples 9-11 and the data in Tables 1 and 2, it can be seen that when beeswax is used as the biowax material, the bonding strength of the hot melt adhesive is improved compared to when soybean wax is used, but when palm wax is used as the biowax material, the bonding strength of the hot melt adhesive is reduced compared to when soybean wax is used. This may be because soybean wax is not only fine and soft, but also has a certain degree of adhesion, which is conducive to increasing the bonding performance and fluidity of the hot melt adhesive, while beeswax and palm wax have higher viscosity and hardness than soybean wax, which can supplement the corresponding viscosity and cohesive strength for the hot melt adhesive, but the hardness of palm wax may be too high, making the colloid brittle after hardening, so that cohesive failure occurs during the tensile test, affecting the bonding strength.

[0077] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A hot melt adhesive with high cohesion, characterized in that: It includes the following raw materials in parts by weight: Base resin: 50-64 parts; Tackifying resin: 18-24 parts; Polyethylene wax: 3.2-4.5 parts; Biological wax: 1.5-2.4 parts; Modified starch granules: 10-16 parts; Maleic anhydride grafted polyethylene: 1.2-3.2 parts; Antioxidant: 0.8-1.2 parts; The base resin comprises a mixture of maleic anhydride grafted APAO resin and PHBV resin in a weight ratio of 1: (0.6-1.5), the tackifying resin comprises a mixture of C5 hydrogenated petroleum resin and rosin polyol ester in a weight ratio of 1: (2-5), the modified starch particles are thermoplastic starch modified by plasticization, and the biowax comprises any one of soybean wax, beeswax or palm wax.

2. A hot melt adhesive with high cohesion according to claim 1, characterized in that: The preparation method of the maleic anhydride grafted APAO resin comprises the following steps: A1. First, maleic anhydride and dicumyl peroxide are fully mixed in a weight ratio of 1: (0.05-0.075), and completely dissolved in acetone as a solvent to obtain a maleic anhydride modified liquid; A2. Add the maleic anhydride modified liquid obtained in step A1 to the APAO resin, wherein the weight ratio of the maleic anhydride to the APAO resin is 1:(25-30), then heat to 180-200°C and stir thoroughly, and then extrude and cool to granulate to obtain the maleic anhydride grafted APAO resin.

3. The hot melt adhesive with high cohesion according to claim 1, characterized in that: The HV content in the PHBV resin is 9%-16% (mol).

4. The hot melt adhesive with high cohesion according to claim 1, characterized in that: The rosin polyol ester is one of rosin glycerol ester and rosin pentaerythritol ester.

5. The hot melt adhesive with high cohesion according to claim 3, characterized in that: The rosin polyol ester is selected from rosin pentaerythritol ester, and the C5 hydrogenated petroleum resin and the rosin pentaerythritol ester are mixed in a weight ratio of 1:(2-3).

6. The hot melt adhesive with high cohesion according to claim 1, characterized in that: The biological wax material is beeswax.

7. The hot melt adhesive with high cohesion according to claim 1, characterized in that: The plasticizing modification of the modified starch granules comprises the following steps: First, corn starch and water are fully mixed at a ratio of 1:1, and then a composite plasticizer composed of glycerol, formamide and urea is added. The mixture is kept at room temperature and fully stirred at a speed of 3000-3500r / min, and then allowed to stand for 24-48 hours. The modified starch particles are obtained by extrusion and cooling.

8. The hot melt adhesive with high cohesion according to claim 7, characterized in that: In the composite plasticizer, the mixing weight ratio of the glycerol, the formamide and the urea is 1:(0.4-0.6):(0.4-0.6), and the mixing weight ratio of the corn starch to the composite plasticizer is 1:(0.2-0.25).

9. The hot melt adhesive with high cohesion according to claim 1, characterized in that: The antioxidant is selected from antioxidant 1010 and antioxidant 168 mixed in a weight ratio of 1: (2-3).

10. A method for preparing a hot melt adhesive with high cohesion, characterized in that: The method for preparing a hot melt adhesive with high cohesion as claimed in any one of claims 1 to 9 comprises the following preparation steps: S1, firstly, 10% of the base resin is fully mixed with polyethylene wax, biowax, maleic anhydride grafted polyethylene and antioxidant at a mixing temperature of 160-175° C., and then the remaining base resin is added, and the mixture is fully stirred to obtain a first mixture; S2, lowering the mixing temperature to 140-150° C., then adding the tackifying resin and the modified starch granules, and continuing stirring for 20-30 minutes to obtain a second mixture; S3, subjecting the second mixture to vacuum exhaust treatment, and then melting and extruding the second mixture, and rapidly drawing it to a circulating cooling water tank with a cooling solution temperature not higher than 5° C. for cooling, and then cutting and drying, thereby obtaining a hot melt adhesive with high cohesive force.

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