Hybrid coordination driven high flowability and matrix strength thermoplastic amine starch-based hot melt adhesive and its preparation and application

Abstract

The application belongs to the technical field of hot melt adhesives, and discloses a hybrid coordination driven hot melt adhesive with high flowability and matrix strength and a preparation method and application of the hot melt adhesive. The hot melt adhesive comprises the following components in parts by mass: hybrid coordination hot melt acrylamide grafted starch 40-80 parts, ethylene-vinyl acetate copolymer 10-30 parts, tackifier 10-30 parts, and antioxidant 0.2-0.4 parts. The hot melt adhesive prepared by using the modified aminated starch is rich in amino groups, and forms strong hydrogen bonds and coordination with the interface, has excellent bonding performance, has good bonding effect on paper and non-woven fabric, has high metal bonding strength, the copper sheet lap bonding strength reaches 6.1 MPa, the aluminum strip peeling strength reaches 1227 N / m, and can be applied to the fields of vehicle interiors, furniture, food, packaging, papermaking, sanitary products and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hot melt adhesives, and particularly relates to a hybrid coordination driven high flow and matrix strength thermoplastic aminated starch-based hot melt adhesive as well as a preparation method and application thereof. BACKGROUND

[0002] Hot melt adhesive is an environmentally friendly, simple to operate and widely applicable adhesive. Most of the current commercial hot melt adhesives are mainly composed of petroleum-based polymers such as ethylene-vinyl acetate copolymer (EVA resin), polyamide and polyurethane. The bonding performance of these materials mainly depends on covalent bonds, and the bonding effect with polar materials such as metals is poor due to the limitation of interfacial phase thickness. In addition, such traditional materials are not easy to naturally degrade, and with the increase of the amount of use, hot melt adhesives face severe challenges in resource conservation and environmental protection.

[0003] Starch, as a common natural resource in nature, has the advantages of abundant source, economy and natural degradation, and is widely used in the preparation of hot melt adhesive materials. However, the current hot melt adhesives containing starch generally have low cohesive force and adhesion to the interface based on hydrogen bonds and other forces, resulting in generally low matrix strength and adhesion strength of the hot melt adhesive. In addition, the original starch usually needs to be plasticized and subjected to shear to destroy the intermolecular hydrogen bonds and granular texture for the preparation of thermoplastic starch (TPS). Although TPS has thermoplasticity, due to the rigid molecular chain structure of starch, it often exhibits low flowability and permeability to the interface, making it difficult to achieve good adhesion to the bonding substrate.

[0004] CN114806463A modifies corn starch with a modifier and a composite plasticizer to improve the processability of thermoplastic starch and obtain a thermoplastic starch-based hot melt adhesive product. Ren et al. use self-modified thermoplastic starch and grafted PCL as the basic raw material, with naphthenic oil as the plasticizer, hydrogenated petroleum resin or hydrogenated rosin resin as the tackifier, to prepare a new type of thermoplastic starch hot melt adhesive by heating and mixing. Patent CN440781 obtains modified starch by sodium hypochlorite oxidation, acrylamide polycondensation, and end group blocking treatment with norbornane diisocyanate, to obtain a hot melt adhesive with high bonding strength, good water resistance and no toxicity. However, the starch content in these starch-containing hot melt adhesives is usually not high, and the key problems of poor flowability of hot melt adhesive at high temperature and weak matrix strength at low temperature cannot be overcome at the same time. SUMMARY

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a hybrid coordination driven high flow and matrix strength thermoplastic aminated starch-based hot melt adhesive.

[0006] Another purpose of the present application is to provide a preparation method of the above-mentioned thermoplastic aminated starch-based hot melt adhesive.

[0007] Still another object of the present application is to provide the use of the above-mentioned thermoplastic amine starch-based hot melt adhesive.

[0008] The object of the present application is achieved by the following solutions:

[0009] A hybrid coordination driven high flowability and matrix strength thermoplastic amine starch-based hot melt adhesive, the components include the following components in mass parts: hybrid coordination thermoplastic acrylamide grafted starch 40-80 parts, ethylene-vinyl acetate copolymer (EVA resin) 10-30 parts, tackifier 10-30 parts, antioxidant 0.2-0.4 parts.

[0010] Further, the viscosity of the tackifier is preferably 700-1800 cp (150°C).

[0011] Further, the tackifier can include at least one of rosin resin, hydrogenated rosin resin, etc., and more preferably includes rosin resin.

[0012] Further, the antioxidant is a conventional antioxidant in the art, such as antioxidant 168, antioxidant 1010, antioxidant 1076, etc., and more preferably includes antioxidant 1010.

[0013] Further, the EVA resin is preferably EVA28400.

[0014] In the thermoplastic amine starch-based hot melt adhesive of the present application, the hybrid coordination thermoplastic acrylamide grafted starch is prepared from components including the following components in mass parts: amine starch 60-75 parts, plasticizer 25-40 parts, metal salt 0.05-10 parts, organic acid 0.05-5 parts.

[0015] Further, the amine group grafting rate of the amine starch is 5-50%, and more preferably includes 10% grafting rate.

[0016] Further, the amine starch can include at least one of acrylamide grafted starch, triethylene tetramine-based starch, amine functionalized dialdehyde starch, etc., and more preferably is acrylamide grafted starch.

[0017] Further, the plasticizer can include at least one of glycerol, ethylene glycol, pentaerythritol, etc., which are commonly used in the art, and more preferably is glycerol.

[0018] Further, the metal salt can include at least one of soluble zinc salt, soluble calcium salt, soluble magnesium salt, etc.

[0019] Further, the soluble zinc salt can include at least one of zinc acetate, zinc chloride, zinc citrate, zinc tartrate, etc.

[0020] Further, the soluble calcium salt can include at least one of calcium tartrate, calcium chloride, calcium acetate, etc.

[0021] Further, the soluble magnesium salt can include magnesium chloride, etc.

[0022] Further, the organic acid can include at least one of malic acid, tannic acid, citric acid, succinic acid, and more preferably malic acid.

[0023] In the thermoplastic amine starch-based hot melt adhesive, the hybrid coordination thermoplastic acrylamide grafted starch is prepared by the following steps: uniformly mixing amine starch, plasticizer and metal salt in proportion, placing them in an extruder for reaction extrusion molding, cooling and granulating to obtain the hybrid coordination thermoplastic acrylamide grafted starch.

[0024] Further, the material can be placed after uniform mixing and then extruded and granulated. The standing time can be 1-48h.

[0025] Further, the extruder used can be a co-rotating parallel twin-screw extruder; the temperature from the extruder feeding port to the die head is 80-140℃, and the screw rotation speed is 50-300r / min, more preferably 120-150r / min.

[0026] The hybrid coordination process of the hybrid coordination thermoplastic acrylamide grafted starch has temperature-sensitive reversible characteristics.

[0027] The amine starch is used as raw material, and is modified by using a plasticizer and a metal salt. Under the action of the plasticizer, metal ion and high-temperature shear field, the amine starch is de-helical, and further forms a mononuclear multi-dentate coordination bond through amino groups / hydroxyl groups and metal ions. The coordination bond has dynamic characteristics, can be dissociated at high temperature and recombined at low temperature, so that the thermoplastic amine starch can improve the matrix strength while maintaining the flowability in hot processing. The thermoplastic amine starch is combined with EVA resin, tackifier and the like to prepare a thermoplastic amine starch-based hot melt adhesive. Compared with the traditional thermoplastic starch-based hot melt adhesive, the hot melt adhesive prepared by using the modified amine starch is rich in amino groups, can form strong hydrogen bonds and coordination with the interface, and has excellent bonding performance. The thermoplastic amine starch-based hot melt adhesive not only has good bonding effect on paper and non-woven fabric, but also has high metal bonding strength, and the copper sheet lap bonding strength can reach 6.1MPa, and the aluminum strip peeling strength can reach 1227N / m.

[0028] The application also provides a preparation method of the thermoplastic amine starch-based hot melt adhesive, which comprises mixing the components in proportion, placing them in an internal mixer for melt blending, cooling and granulating to prepare the thermoplastic amine starch-based hot melt adhesive.

[0029] Further, the temperature of the internal mixer can be 120-170 DEG C, the rotor rotation speed can be 5-120 r / min, and the mixing time can be 5-60 min.

[0030] Further, the temperature of the internal mixer can be 140-150 DEG C, the rotor rotation speed can be 80-120 r / min, and the mixing time can be 10-40 min.

[0031] The application further provides application of the thermoplastic amine-modified starch-based hot melt adhesive.

[0032] Compared with the prior art, the application has the following advantages:

[0033] (1) The thermoplastic amine-modified starch-based hot melt adhesive has good adhesion to paper and non-woven fabric, and has high metal adhesion strength, and the copper sheet lap adhesion strength can reach 6.1 MPa, and the aluminum strip peeling strength can reach 1227 N / m.

[0034] (2) Based on the excellent adhesion of the thermoplastic amine-modified starch-based hot melt adhesive to metal materials, fillers can be added to the components to increase the strength of the adhesive matrix without damaging the adhesion strength to the metal, thereby further improving the adhesion of the thermoplastic amine-modified starch-based hot melt adhesive to the metal matrix.

[0035] (3) The metal salt in the components of the thermoplastic amine-modified starch-based hot melt adhesive can promote the rupture of glycosidic bonds during thermoplastic processing, that is, it has a degradation effect on the starch molecular chain, reduces the molecular weight of the starch, widens the molecular weight distribution, reduces the molecular chain entanglement, and converts the originally rigid and brittle thermoplastic starch into soft and sticky thermoplastic amine-modified starch. Through this conversion, the acidified and modified TPS can be used as the main material (not filler) of the hot melt adhesive, which can not only provide a large number of hydroxyl groups to improve the adhesion force between the adhesive interface, but also eliminate the use of non-degradable viscosity regulators. In addition, the mononuclear and multi-tooth coordination structure formed by the metal ion and the amine group / hydroxyl group can endow the hot melt adhesive with excellent high-temperature fluidity and low-temperature strong adhesion temperature-sensitive reversible dynamic properties.

[0036] (4) the flowability of the thermoplastic aminated starch-based hot melt adhesive after hybrid coordination is good in the high-temperature processing process, the proportion of the thermoplastic aminated starch-based hot melt adhesive in the hot melt adhesive is greatly improved (the mass proportion is up to 80wt%), and the use of petroleum-based materials can be greatly reduced; the thermoplastic aminated starch-based hot melt adhesive prepared by taking aminated starch, glycerol and rosin resin as main raw materials has good biodegradability; the hot melt adhesive not only has high efficiency in the preparation process, but also can be reused, and is more friendly to the environment. The thermoplastic aminated starch-based hot melt adhesive prepared by the application can be widely applied, such as bonding paper, non-woven fabric, metal and the like, and can be applied in the interior decoration of vehicles, furniture, packaging and the like. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0038] Figure 1 SEM image of the thermoplastic aminated starch-based hot melt adhesive of the application.

[0039] Figures 2-3 SEM images of the hot melt adhesives prepared by Comparative Example 1 and Comparative Example 2, respectively. DETAILED DESCRIPTION

[0040] The application will be further described in detail below in combination with the embodiments, but the embodiments of the application are not limited thereto. The materials involved in the following examples can be obtained from commercial channels if no special instructions are given. The methods are conventional methods if no special instructions are given. The amount of each component is measured by mass volume parts, g and mL.

[0041] The EVA resin (brand: EVA28400) used in the following examples was purchased from Shanghai Haiyuan Chemical Co., Ltd.; the rosin resin was purchased from Jinan Fugang Chemical Co., Ltd., the viscosity was 700-1800cp (150℃), and the softening point was 110-120℃.

[0042] Example 1

[0043] 70 parts by mass of acrylamide grafted starch, 30 parts by mass of glycerol, 3 parts by mass of zinc acetate, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added to a co-rotating twin-screw extruder for reaction extrusion. The temperature from the feeding port to the die head of the extruder was set to 90-140°C (the temperature in each temperature control zone from the feeding port to the die head of the extruder was set to 90°C, 110°C, 130°C, 135°C, 140°C, 140°C, 135°C, and 130°C, respectively), and the screw rotation speed was 150 r / min. After cooling and granulation, hybrid coordination thermoplastic acrylamide starch particles were obtained.

[0044] After 50 parts by mass of the hybrid coordination thermoplastic acrylamide starch prepared above, 25 parts by mass of EVA resin, 25 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, they were added to an internal mixer for melt blending. The temperature of the internal mixer was 150°C, the rotor rotation speed was 80 r / min, and after mixing for 10 min, the material was discharged, cooled, and granulated to obtain a thermoplastic acrylamide starch-based hot melt adhesive.

[0045] Example 2

[0046] 70 parts by mass of acrylamide grafted starch, 30 parts by mass of glycerol, 3 parts by mass of zinc acetate, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added to a co-rotating twin-screw extruder for reaction extrusion. The temperature from the feeding port to the die head of the extruder was set to 90-140°C (the temperature in each temperature control zone from the feeding port to the die head of the extruder was set to 90°C, 110°C, 130°C, 135°C, 140°C, 140°C, 135°C, and 130°C, respectively), and the screw rotation speed was 150 r / min. After cooling and granulation, hybrid coordination thermoplastic acrylamide starch particles were obtained.

[0047] After 60 parts by mass of the hybrid coordination thermoplastic acrylamide starch, 20 parts by mass of EVA resin, 20 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, they were added to an internal mixer for melt blending. The temperature of the internal mixer was 150°C, the rotor rotation speed was 90 r / min, and after mixing for 20 min, the material was discharged, cooled, and granulated to obtain a thermoplastic acrylamide starch-based hot melt adhesive.

[0048] Example 3

[0049] 70 parts by mass of acrylamide grafted starch, 30 parts by mass of glycerol, 3 parts by mass of zinc acetate, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added into a co-rotating twin-screw extruder for reactive extrusion, with the temperature of the feeding port to the die of the extruder set to 90-140°C (the temperature of each temperature control zone from the feeding port to the die of the extruder set to 90°C, 110°C, 130°C, 135°C, 140°C, 140°C, 135°C, and 130°C, respectively), and the screw rotation speed set to 150 r / min, to obtain hybrid coordination thermoplastic acrylamide starch particles after cooling and granulation.

[0050] After 70 parts by mass of hybrid coordination thermoplastic acrylamide starch, 15 parts by mass of EVA resin, 15 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, they were added into an internal mixer for melt blending, with the temperature of the internal mixer set to 150°C and the rotor rotation speed set to 100 r / min, to obtain thermoplastic acrylamide starch-based hot melt adhesive after discharging, cooling, and granulation after mixing for 30 min.

[0051] Example 4

[0052] 70 parts by mass of acrylamide grafted starch, 30 parts by mass of glycerol, 3 parts by mass of zinc acetate, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added into a co-rotating twin-screw extruder for reactive extrusion, with the temperature of the feeding port to the die of the extruder set to 90-140°C (the temperature of each temperature control zone from the feeding port to the die of the extruder set to 90°C, 110°C, 130°C, 135°C, 140°C, 140°C, 135°C, and 130°C, respectively), and the screw rotation speed set to 150 r / min, to obtain hybrid coordination thermoplastic acrylamide starch particles after cooling and granulation.

[0053] After 80 parts by mass of hybrid coordination thermoplastic acrylamide starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, they were added into an internal mixer for melt blending, with the temperature of the internal mixer set to 150°C and the rotor rotation speed set to 110 r / min, to obtain thermoplastic acrylamide starch-based hot melt adhesive after discharging, cooling, and granulation after mixing for 40 min.

[0054] Example 5

[0055] 80 parts by mass of the hybrid coordination thermoplastic triethylenetetramine starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 are uniformly premixed by mechanical stirring, and then are fed into an internal mixer to be melt blended, with the temperature of the internal mixer being 140°C and the rotor speed being 120 r / min. After mixing for 40 min, the material is discharged, cooled, and granulated to obtain a hot-melt adhesive based on thermoplastic triethylenetetramine starch.

[0056] 80 parts by mass of the hybrid coordination thermoplastic triethylenetetramine starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 are uniformly premixed by mechanical stirring, and then are fed into an internal mixer to be melt blended, with the temperature of the internal mixer being 140°C and the rotor speed being 120 r / min. After mixing for 40 min, the material is discharged, cooled, and granulated to obtain a hot-melt adhesive based on thermoplastic triethylenetetramine starch.

[0057] Example 6

[0058] 80 parts by mass of the hybrid coordination thermoplastic triethylenetetramine starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 are uniformly premixed by mechanical stirring, and then are fed into an internal mixer to be melt blended, with the temperature of the internal mixer being 140°C and the rotor speed being 120 r / min. After mixing for 40 min, the material is discharged, cooled, and granulated to obtain a hot-melt adhesive based on thermoplastic triethylenetetramine starch.

[0059] 80 parts by mass of the hybrid coordination thermoplastic triethylenetetramine starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 are uniformly premixed by mechanical stirring, and then are fed into an internal mixer to be melt blended, with the temperature of the internal mixer being 140°C and the rotor speed being 120 r / min. After mixing for 40 min, the material is discharged, cooled, and granulated to obtain a hot-melt adhesive based on thermoplastic triethylenetetramine starch.

[0060] Example 7

[0061] 80 parts by mass of the hybrid coordination thermoplastic acrylamide grafted starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then were added into an internal mixer for melt blending. The temperature of the internal mixer was 140°C, and the rotor speed was 120 r / min. After mixing for 40 min, the material was discharged, cooled, and granulated to obtain a hot-melt adhesive based on the thermoplastic acrylamide grafted starch.

[0062] 80 parts by mass of the hybrid coordination thermoplastic acrylamide grafted starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then were added into an internal mixer for melt blending. The temperature of the internal mixer was 140°C, and the rotor speed was 120 r / min. After mixing for 40 min, the material was discharged, cooled, and granulated to obtain a hot-melt adhesive based on the thermoplastic acrylamide grafted starch.

[0063] Example 8

[0064] 80 parts by mass of the hybrid coordination thermoplastic acrylamide grafted starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then were added into an internal mixer for melt blending. The temperature of the internal mixer was 140°C, and the rotor speed was 120 r / min. After mixing for 40 min, the material was discharged, cooled, and granulated to obtain a hot-melt adhesive based on the thermoplastic acrylamide grafted starch.

[0065] 80 parts by mass of the hybrid coordination thermoplastic acrylamide grafted starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then were added into an internal mixer for melt blending. The temperature of the internal mixer was 140°C, and the rotor speed was 120 r / min. After mixing for 40 min, the material was discharged, cooled, and granulated to obtain a hot-melt adhesive based on the thermoplastic acrylamide grafted starch.

[0066] Example 9

[0067] 70 parts by mass of acrylamide grafted starch, 30 parts by mass of glycerol, 4 parts by mass of calcium acetate, 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added into a co-rotating twin-screw extruder for reactive extrusion, the temperature from the feeding port to the die head of the extruder was set to 80-130°C (the temperature in each temperature control interval from the feeding port to the die head of the extruder was set to 80°C, 100°C, 120°C, 125°C, 130°C, 130°C, 125°C, 120°C), the screw rotation speed was 120 r / min, and after cooling and granulation, a hybrid coordination thermoplastic acrylamide grafted starch was obtained.

[0068] 80 parts by mass of the hybrid coordination thermoplastic acrylamide grafted starch, 10 parts by mass of EVA resin, 10 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then added into an internal mixer for melt blending, the temperature of the internal mixer was 150°C, the rotor rotation speed was 120 r / min, and after mixing for 40 min, the material was discharged, cooled and granulated to obtain a thermoplastic acrylamide grafted starch-based hot melt adhesive.

[0069] Comparative Example 1

[0070] 70 parts by mass of ordinary corn starch, 30 parts by mass of glycerol, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added into a co-rotating twin-screw extruder for reactive extrusion, the temperature from the feeding port to the die head of the extruder was set to 80-130°C (the temperature in each temperature control interval from the feeding port to the die head of the extruder was set to 80°C, 100°C, 120°C, 125°C, 130°C, 130°C, 125°C, 120°C), the screw rotation speed was 120 r / min, and after cooling and granulation, a thermoplastic starch was obtained.

[0071] 60 parts by mass of the thermoplastic starch, 20 parts by mass of EVA resin, 20 parts by mass of rosin resin, and 0.4 parts by mass of antioxidant 1010 were uniformly premixed by mechanical stirring, and then added into an internal mixer for melt blending, the temperature of the internal mixer was 150°C, the rotor rotation speed was 120 r / min, and after mixing for 40 min, the material was discharged, cooled and granulated to obtain a thermoplastic starch-based hot melt adhesive.

[0072] Comparative Example 2

[0073] 70 parts by mass of acrylamide grafted corn starch, 30 parts by mass of glycerol, and 1 part by mass of malic acid were mixed uniformly in a blender, and after standing for 24 h, they were added into a co-rotating twin-screw extruder for reactive extrusion, the temperature from the feeding port to the die head of the extruder was set to 90-140°C (the temperature in each temperature control interval from the feeding port to the die head of the extruder was set to 90°C, 110°C, 130°C, 135°C, 140°C, 140°C, 135°C, 130°C), the screw rotation speed was 150 r / min, and after cooling and granulation, a thermoplastic acrylamide grafted starch particle without hybrid coordination was obtained.

[0074] 80 parts by mass of the thermoplastic acrylamide grafted starch without hybrid coordination, 20 parts by mass of the EVA resin, 20 parts by mass of the rosin resin, and 0.4 parts by mass of the antioxidant 1010 were uniformly premixed by mechanical stirring, and then were added into an internal mixer for melt blending. The temperature of the internal mixer was 150°C, the rotor speed was 110 r / min, and the material was discharged after being mixed for 40 min, and then was cooled and granulated to obtain the thermoplastic acrylamide grafted starch-based hot melt adhesive without hybrid coordination.

[0075] The hot melt adhesives prepared in the above Examples 1-9 and Comparative Examples 1-2 were subjected to copper sheet lap shear strength test (tested according to the standard GB / T 7124-2008, and the tensile rate was set to 5 mm / min) and aluminum tape peel strength test (tested according to the standard GB / T 2791-1995, and the tensile rate was 200 mm / min). The test results are shown in Table 1.

[0076] Table 1

[0077]

[0078] As shown in Table 1, the addition of the hybrid coordination thermoplastic acrylamide grafted starch of the present application significantly improves the adhesion strength of the hot melt adhesive to metal. Specifically, on the one hand, the addition of the thermoplastic aminated starch significantly improves the adhesion strength of the hot melt adhesive, and on the other hand, the hybrid coordination is crucial for improving the strength of the hot melt adhesive matrix. The hot melt adhesive is bonded to the substrate interface through hydrogen bonding force after sufficient contact with the bonding substrate, so good wetting and rich polar groups are beneficial to improve the interfacial adhesion strength. In addition, the cohesive energy density and molecular weight distribution of the adhesive play a decisive role in the adhesion strength. The metal salt is coordinated with the metal in the process of melt extruding the thermoplastic aminated starch, which activates and breaks the glycosidic bond in the starch chain, causes the molecular chain to entangle and reduce, the molecular weight decreases, the molecular weight distribution becomes wide from narrow, and the thermoplastic starch changes from rigid to flexible. The increase in the number of small molecules can improve the flowability of the thermoplastic starch, which is beneficial to the wetting of the hot melt adhesive to the bonding substrate, and the part with large molecular weight maintains the matrix strength of the thermoplastic starch.

[0079] Furthermore, hybrid coordination exhibits the characteristics of high-temperature dissociation and low-temperature recombination. This feature satisfies the requirement of good flowability of hot melt adhesives at high temperatures while also providing the necessary high cohesive energy density at low temperatures. In addition, hybrid coordination of small-molecule starch chains can increase their apparent molecular weight, contributing to improved toughness and cohesive energy density of the hot melt adhesive matrix and mitigating cohesive failure issues caused by low-molecular-weight components. Amination modification of starch chains introduces amino-rich side chains, promoting strong interactions between starch chains through amino-hydroxyl-enhanced hydrogen bonding. More importantly, flexible amino groups diffuse more easily into the bonding matrix, forming a strong adhesive interface layer, thereby enhancing the affinity and adhesive strength between the hot melt adhesive and the bonding matrix. Through the introduction of metal ions, the hot melt adhesive possesses metal-amino and metal-hydroxyl coordination. The resulting hybrid coordination reversible crosslinking network effectively dissipates external stress in the thermoplastic amino-modified starch chains, significantly improving the matrix strength. Therefore, by amination modification of starch and introduction of metal salt coordination, thermoplastic amination starch-based hot melt adhesives with high flowability and matrix strength can be achieved through hybrid coordination.

[0080] Furthermore, the compatibility of the hot melt adhesive was observed using SEM. Figure 1 This is a SEM image of the hybrid coordination thermoplastic acrylamide-grafted starch-based hot melt adhesive of Example 4 of the present invention. Figure 2 and Figure 3 SEM images of the non-hybridized ordinary thermoplastic starch-based hot melt adhesive and the non-hybridized thermoplastic acrylamide-grafted hot melt adhesive prepared in Comparative Examples 1 and 2, respectively.

[0081] As shown in the figure, the hybrid coordination thermoplastic acrylamide-grafted starch in the hot melt adhesive of this invention exhibits better interfacial compatibility with EVA resin and rosin resin. Specifically, the EVA / rosin resin phase domains within the hybrid coordination thermoplastic acrylamide-grafted starch matrix are smaller, primarily concentrated in the nanoscale range. This characteristic helps reduce adhesion defects in the hybrid coordination thermoplastic acrylamide-grafted starch-based hot melt adhesive, improving its adhesion uniformity and interfacial layer thickness. In comparison, Figure 2 and Figure 3 The EVA / rosin resin is basically dispersed in micron-sized phase domains in the unhybridized thermoplastic starch / acrylamide grafted starch hot melt adhesive. This phenomenon fully demonstrates that the hybridized thermoplastic aminated starch helps to significantly improve the dispersibility of EVA / rosin resin.

[0082] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A hybrid coordination-driven thermoplastic aminated starch-based hot melt adhesive with high flowability and matrix strength, characterized in that... The composition includes the following components in parts by weight: 40-80 parts of hybrid coordination thermoplastic acrylamide grafted starch, 10-30 parts of ethylene-vinyl acetate copolymer, 10-30 parts of tackifier, and 0.2-0.4 parts of antioxidant; Hybridized coordination thermoplastic acrylamide-grafted starch is prepared from the following components in parts by weight: 60-75 parts of aminated starch, 25-40 parts of plasticizer, 0.05-10 parts of metal salt, and 0.05-5 parts of organic acid; wherein the metal salt includes at least one of soluble zinc salt, soluble calcium salt, and soluble magnesium salt.

2. The thermoplastic aminated starch-based hot melt adhesive according to claim 1, characterized in that: The tackifier includes at least one of rosin resin and hydrogenated rosin resin; the antioxidant includes at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076.

3. The thermoplastic aminated starch-based hot melt adhesive according to claim 1, characterized in that: The amino grafting rate of the aminated starch is 5-50%.

4. The thermoplastic aminated starch-based hot melt adhesive according to claim 1, characterized in that: The aminated starch includes at least one of acrylamide-grafted starch, triethylenetetramine starch, and amino-functionalized dialdehyde starch; the plasticizer includes at least one of glycerol, ethylene glycol, and pentaerythritol; and the organic acid includes at least one of malic acid, tannic acid, citric acid, and succinic acid.

5. The thermoplastic aminated starch-based hot melt adhesive according to claim 1, characterized in that: The soluble zinc salt includes at least one of zinc acetate, zinc chloride, zinc citrate, and zinc tartrate; the soluble calcium salt includes at least one of calcium tartrate, calcium chloride, and calcium acetate; and the soluble magnesium salt includes magnesium chloride.

6. A method for preparing the thermoplastic aminated starch-based hot melt adhesive according to any one of claims 1-5, characterized in that... The process involves mixing the components in proportion, melting and blending them in an internal mixer, cooling and granulating them to prepare a thermoplastic aminated starch-based hot melt adhesive.

7. The preparation method according to claim 6, characterized in that... The internal mixer temperature is 120-170℃, the rotor speed is 5-120 r / min, and the mixing time is 5-60 min.

8. The application of the thermoplastic aminated starch-based hot melt adhesive according to any one of claims 1-5 in the fields of vehicle interiors, furniture, food, packaging, papermaking, and hygiene products.

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