Hot melt adhesive with high foaming rate as well as preparation and application of hot melt adhesive

Abstract

The invention relates to the field of hot melt adhesives, and provides a high-foaming-rate hot melt adhesive as well as preparation and application thereof, the hot melt adhesive comprises a polyolefin elastomer and a functional polymer in a mass ratio of (40-90): (1-10), the functional polymer is a copolymer of a first monomer and a second monomer; the first monomer is selected from one or a combination of more than two of an ethylene monomer, a propylene monomer, a butylene monomer, a hexene monomer and an octene monomer, and the second monomer is selected from one or a combination of more than two of maleic anhydride, acrylic acid and acrylic acid derivatives; the content of the second monomer in the functional polymer is 1-30%. According to the invention, by adding the functional polymer with a specific structure and content, the cohesion strength of the material is improved, and empty cells can be supported in the foaming process, so that the foaming rate is improved, and the cohesion strength of the material is also favorably improved. Meanwhile, functional groups of the functional polymer can also increase the binding power of the hot melt adhesive material to metal.

Description

Technical Field

[0001] The present invention relates to the technical field of hot melt adhesives, and in particular to a high foaming rate hot melt adhesive and a preparation method and application thereof. Background Art

[0002] Currently, three types of materials are mainly used to seal the corner seams of air-conditioning evaporators: silicone sealing damping strips, EVA hot melt adhesives, and polyolefin elastomer hot melt adhesives.

[0003] Silicone sealing damping strips have disadvantages such as poor sealing performance, inconvenient operation, and low efficiency. EVA hot melt adhesives use ethylene-vinyl acetate copolymer as raw material, have poor thermal stability, decompose some low-molecular acidic substances, and require a lot of glue. The above two types of hot melt adhesives are gradually being replaced by polyolefin elastomer hot melt adhesives in market applications. At present, polyolefin elastomer hot melt adhesives also have certain problems, because the cost of polyolefin elastomer materials is relatively high. In order to reduce costs, foaming and gluing are performed during use, but the foaming degree of the polyolefin elastomer hot melt adhesives currently used is relatively low, generally around 40~50%. Summary of the invention

[0004] As mentioned above, the sealant used for sealing the corner seam of the air conditioner evaporator must meet the requirements of good sealing performance, good thermal stability and low cost. Although foaming and gluing polyolefin elastomer hot melt adhesive can solve some of the above problems, such as effectively avoiding the shortcomings of poor sealing performance, inconvenient operation and low efficiency of silicone sealing damping strips, and the shortcomings of EVA hot melt adhesives such as large glue consumption and precipitation of acidic substances that corrode evaporator components, polyolefin elastomer hot melt adhesives have a foaming process, and how to further improve its foaming rate has become a technical problem that needs to be overcome in this field.

[0005] The present invention provides a high foaming rate hot melt adhesive and its preparation and application. A specific type of functional polymer is introduced into an existing polyolefin elastomer hot melt adhesive system to obtain an improved hot melt adhesive, thereby realizing the preparation of a polyolefin elastomer hot melt adhesive with a high foaming rate. At the same time, the polyolefin elastomer hot melt adhesive with a high foaming rate also exhibits a technical feature of high adhesion, thereby improving the sealing performance of the hot melt adhesive. In applications with high requirements for properties such as foaming and sealing, such as air conditioner evaporator sealing materials, the invention has technical advantages.

[0006] Specifically, in a first aspect, the present invention provides a high foaming rate hot melt adhesive, comprising: a polyolefin elastomer and a functional polymer in a mass ratio of 40 to 90:1 to 10; The functional polymer is a copolymer of a first monomer and a second monomer; the content of the second monomer in the functional polymer is 1-30%; The first monomer is selected from one or a combination of two or more of ethylene monomer, propylene monomer, butene monomer, hexene monomer and octene monomer; The second monomer is selected from one or a combination of two or more of maleic anhydride, acrylic acid and acrylic acid derivatives.

[0007] According to the high foaming rate hot melt adhesive provided by the present invention, the acrylic acid derivative is selected from one or a combination of two or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate and glycidyl methacrylate.

[0008] The high foaming rate hot melt adhesive provided by the present invention further comprises: a tackifying resin; the mass ratio of the polyolefin elastomer to the tackifying resin is 40-90:5-40; Preferably, the tackifying resin is selected from one or a combination of two or more of rosin resin, petroleum resin and terpene resin.

[0009] According to the high foaming rate hot melt adhesive provided by the present invention, the petroleum resin is selected from one or a combination of two or more of C5 petroleum resin, hydrogenated C5 petroleum resin, C9 petroleum resin and hydrogenated C9 petroleum resin.

[0010] The high foaming rate hot melt adhesive provided by the present invention further includes polyisobutylene; the mass ratio of the polyolefin elastomer to the polyisobutylene is 40-90:1-20.

[0011] The high foaming rate hot melt adhesive provided by the present invention further includes a thermal oxidation stabilizer; the mass ratio of the polyolefin elastomer to the thermal oxidation stabilizer is 40-90:0.1-1; Preferably, the thermal oxidation stabilizer is a hindered phenol antioxidant and / or a phosphite antioxidant.

[0012] According to the high foaming rate hot melt adhesive provided by the present invention, the basic monomer constituting the polyolefin elastomer is ethylene.

[0013] According to the high foaming rate hot melt adhesive provided by the present invention, the raw materials of the high foaming rate hot melt adhesive include, by weight: 40-90 parts of polyolefin elastomer, 1-20 parts of polyisobutylene, 5-40 parts of tackifying resin, 1-10 parts of functional polymer, and 0.1-1 parts of thermal oxidation stabilizer. It was found in the experiment that the hot melt adhesive prepared by adopting this formula has better performance.

[0014] In a second aspect, the present invention also provides a method for preparing the high foaming rate hot melt adhesive as described above, wherein the high foaming rate hot melt adhesive is obtained by melting and mixing the raw materials and then molding them.

[0015] According to the method for preparing the high foaming rate hot melt adhesive provided by the present invention, the temperature of the melt mixing is 140-200°C.

[0016] In a third aspect, the present invention further provides the use of the high foaming rate hot melt adhesive as described above or the high foaming rate hot melt adhesive prepared by the preparation method as described above in sealing corner seams.

[0017] In a fourth aspect, the present invention also provides a sheet member containing a folded corner seam, wherein the folded corner seam is sealed using the high foaming rate hot melt adhesive as described above or the high foaming rate hot melt adhesive prepared by the preparation method as described above.

[0018] The high foaming rate hot melt adhesive provided by the present invention and its preparation and application improve the cohesive strength of the material by adding a functional polymer with a specific structure and content, so that the hollow cells can be supported during the foaming process, thereby improving the foaming rate and also facilitating the improvement of the cohesive strength of the material. At the same time, the functional groups on the functional polymer can also increase the bonding force of the hot melt adhesive material to the metal. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In an embodiment of the present invention, a high foaming rate hot melt adhesive is first provided, comprising: a polyolefin elastomer and a functional polymer in a mass ratio of 40-90:1-10; The functional polymer is a copolymer of a first monomer and a second monomer; the content of the second monomer in the functional polymer is 1-30%; The first monomer is selected from one or a combination of two or more of ethylene monomer, propylene monomer, butene monomer, hexene monomer and octene monomer; The second monomer is selected from one or a combination of two or more of maleic anhydride, acrylic acid and acrylic acid derivatives.

[0021] In the present invention, the first monomer constituting the functional polymer is a basic monomer of the functional polymer and has good compatibility with the polyolefin elastomer, and the second monomer, in addition to the group copolymerized with the first monomer, also contains other reactive groups, such as carbonyl or epoxy groups, etc., and these reactive groups make the functional polymer have certain reactivity. When the functional polymer is added to the hot melt adhesive, on the one hand, the functional polymer can increase the intermolecular force of each polymer chain constituting the hot melt adhesive, that is, the cohesive strength of the hot melt adhesive is increased, so that when the hot melt adhesive is used, the cohesive strength can support the hollow cell structure, achieve a higher foaming ratio, and the foaming structure has good stability and high strength; on the other hand, when the hot melt adhesive is used, the functional polymer can also react with the material in contact with it, that is, the bonding force of the hot melt adhesive to materials such as metals is increased.

[0022] In the above-mentioned functional polymer, the content of the second monomer should be appropriate. In order to ensure the above-mentioned two effects, the content of the second monomer should be above 1%. If the content of the second monomer is too high, the hot melt adhesive will lose fluidity and cannot be processed. Therefore, the content of the second monomer in the functional polymer should be controlled within 30%.

[0023] In a specific embodiment of the present invention, the content of the second monomer in the functional polymer is 1-30%, for example, it can be any value of 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29% and 30%, or a range of any value.

[0024] Preferably, the molecular weight of the functional polymer of the present invention is Mn=10000-200000.

[0025] Preferably, when the functional polymer is a mixture of two or more monomers as the second monomer, it is more conducive to improving the cohesive strength of the hot melt adhesive of the present invention; further preferably, the second monomer is preferably a mixture of maleic anhydride and acrylic acid derivatives, and more preferably, the mass ratio of maleic anhydride to acrylic acid derivatives is 1:5~1:1.

[0026] It is found in experiments that the closer the molecular chain structure of the first monomer used in the functional polymer is to the basic monomer used in the polyolefin elastomer, the better the compatibility between the components, and the more conducive it is to form the intermolecular forces between the components. Therefore, it is preferred that the first monomer is the same as the monomer constituting the polyolefin elastomer; more preferably, the first monomer is the same as the basic monomer constituting the polyolefin elastomer.

[0027] In a specific embodiment of the present invention, the acrylic acid derivative is selected from one or a combination of two or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate and glycidyl methacrylate.

[0028] In a specific embodiment of the present invention, it further comprises: a tackifying resin; the mass ratio of the polyolefin elastomer to the tackifying resin is 40~90:5~40; preferably 50~80:10~30; further preferably 60~70:15~20.

[0029] In the hot melt adhesive of the present invention, the role of the tackifying resin includes adjusting the adhesive force of the hot melt adhesive to the substrate and adjusting the stability of the pore structure formed during the foaming process of the hot melt adhesive. The stability of the pores is closely related to the crystallization performance and shrinkage performance of the hot melt adhesive. Experiments have found that if the content of the tackifying resin is too high, the viscosity of the formula system will be too low and the fluidity will be too good, so that it is not easy to apply the glue and it will flow away between the gaps of the evaporator metal sheets; at the same time, the cohesive strength of the hot melt adhesive system decreases and the foaming is unstable. If the content of the tackifying resin is too low, the viscosity of the formula system will be too high, the wetting performance will be poor, the surface will not be able to adhere to the evaporator well, and the adhesion will be low.

[0030] Preferably, the tackifying resin is selected from one or a combination of two or more of rosin resin, petroleum resin and terpene resin.

[0031] Compared with other substances, the above-mentioned tackifying resin selected in the present invention is more suitable for the present invention in terms of better compatibility with the base resin polyolefin elastomer and better wettability with the metal surface of the evaporator.

[0032] In a specific embodiment of the present invention, the petroleum resin is selected from one or a combination of two or more of C5 petroleum resin, hydrogenated C5 petroleum resin, C9 petroleum resin and hydrogenated C9 petroleum resin.

[0033] In a specific embodiment of the present invention, polyisobutylene is also included; the mass ratio of the polyolefin elastomer to the polyisobutylene is 40-90:1-20.

[0034] Preferably, the kinematic viscosity (100°C) of the polyisobutylene is 300-3000 mm 2 / s.

[0035] In a specific embodiment of the present invention, a heat-oxidation stabilizer is further included; the mass ratio of the polyolefin elastomer to the heat-oxidation stabilizer is 40-90:0.1-1; Preferably, the thermal oxidation stabilizer is a hindered phenol antioxidant and / or a phosphite antioxidant.

[0036] In a specific embodiment of the present invention, the basic monomer constituting the polyolefin elastomer is ethylene.

[0037] Preferably, other monomers constituting the polyolefin elastomer are one or a combination of two or more of propylene, butene, hexene and octene.

[0038] The polyolefin elastomer includes random and / or regular polyolefins.

[0039] In the embodiment of the present invention, when the other monomers constituting the polyolefin elastomer are propylene monomers, the material itself has higher cohesive strength and better foaming performance.

[0040] In a specific embodiment of the present invention, the raw materials of the high foaming rate hot melt adhesive include, by weight: 40-90 parts of polyolefin elastomer, 1-20 parts of polyisobutylene, 5-40 parts of tackifying resin, 1-10 parts of functional polymer, and 0.1-1 part of thermal oxidation stabilizer.

[0041] In a specific embodiment of the present invention, the polyolefin elastomer is 40 to 90 parts, for example, it can be any value or a range of any value among 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts and 90 parts.

[0042] In a specific embodiment of the present invention, the polyisobutylene is 1 to 20 parts, for example, it can be any value among 1 part, 3 parts, 5 parts, 7 parts, 9 parts, 11 parts, 13 parts, 15 parts, 17 parts, 19 parts and 20 parts, or a range consisting of any values.

[0043] In a specific embodiment of the present invention, the tackifying resin is 5 to 40 parts, for example, it can be any value among 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts and 40 parts, or a range consisting of any values.

[0044] In a specific embodiment of the present invention, the functional polymer is 1 to 10 parts, for example, it can be any value among 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts and 10 parts, or a range consisting of any values.

[0045] In a specific embodiment of the present invention, the thermal oxidation stabilizer is 0.1 to 1 part, for example, it can be any value or a range of any value among 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part and 1.0 part.

[0046] In an embodiment of the present invention, a method for preparing the high foaming rate hot melt adhesive as described above is also provided, wherein the high foaming rate hot melt adhesive is obtained by melting and mixing the raw materials and then molding them.

[0047] In a specific embodiment of the present invention, the temperature of the melt mixing is 140-200°C.

[0048] In a specific embodiment of the present invention, the preparation method comprises the following steps: The tackifying resin, polyisobutylene and thermal oxidation stabilizer are melt-mixed at a temperature of 140 to 200° C. for 20 to 60 minutes to obtain a first mixture; Melting and mixing the functional polymer, the polyolefin elastomer and the first mixture at a temperature of 140-200° C. for 50-80 minutes to obtain a second mixture; After the temperature of the second mixture is lowered to 140-160° C., vacuum is drawn until there are no bubbles, and then molding is performed.

[0049] The molding of the present invention can be carried out by using molding equipment such as an underwater pelletizer and a steel belt pelletizer, and after molding, cooling, drying, packaging and other steps can be optionally performed.

[0050] In the processing of the hot melt adhesive of the present invention, it is necessary to control the order of adding each raw material, that is, first mix the tackifying resin, polyisobutylene and thermal oxidation stabilizer, mainly for premixing the non-matrix resin and the auxiliary agent, and then mix the functional polymer and the polyolefin elastomer with the aforementioned mixed materials, so as to better disperse and mix the matrix resin with the non-matrix resin and the auxiliary agent. Moreover, in the above mixing process, the temperature is controlled within the range of 140 to 200° C., which is conducive to the melting of all materials, and the viscosity is moderate, which is suitable for the dispersed distribution mixing of the non-matrix resin and the auxiliary agent.

[0051] In an embodiment of the present invention, there is also provided the use of the high foaming rate hot melt adhesive as described above or the high foaming rate hot melt adhesive prepared by the preparation method as described above in sealing the folded corner seam.

[0052] In a specific embodiment of the present invention, the application includes: sealing the corner seam of an air conditioner evaporator.

[0053] In an embodiment of the present invention, a plate member containing a folded corner seam is further provided, wherein the folded corner seam is sealed using the high foaming rate hot melt adhesive as described above or the high foaming rate hot melt adhesive prepared by the preparation method as described above.

[0054] The preferred embodiments of the present invention are described in detail below. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in the art or the product instructions are used. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased through regular channels.

[0055] The APAO grades used in the present invention include, but are not limited to, one or a combination of two or more selected from 308, 408, 508, 520, 608, EPV2103, EP V2094, 703, 704, 708, 750, 751, 792, 828 and 888, RT2115, RT 2180, RT2215, RT3460, RT2732, etc. All APAO resin grades currently available on the market can also achieve the purpose of the present invention.

[0056] Example 1 A high foaming rate hot melt adhesive, the raw material composition of which is shown in the following table by weight:

[0057] A method for preparing a high foaming rate hot melt adhesive, wherein the raw materials are prepared according to the above raw material composition, and the specific preparation steps are as follows: (1) Heat the reactor to 180°C.

[0058] (2) The above-mentioned tackifying resin, polyisobutylene and thermal oxidation stabilizer are sequentially added into the reactor heated in step (1), the temperature is maintained at 180° C., and stirred for 40 minutes until all the raw materials are completely melted and mixed.

[0059] (3) The functional polymer and polyolefin elastomer are added to the reactor of step (2), the temperature is maintained at 180°C, and stirred for 70 minutes until all the materials are completely melted and mixed evenly.

[0060] (4) The temperature of the material after being evenly mixed in step (3) is lowered to 140°C, the reaction kettle is sealed, and the reaction kettle is stirred and evacuated until there are no bubbles.

[0061] (5) The material obtained in step (4) is placed in a storage tank, and the valve is opened to allow the material to be discharged to an underwater pelletizer for molding to obtain a hot melt adhesive with a high foaming rate.

[0062] Example 2 A high foaming rate hot melt adhesive, the raw material composition of which is shown in the following table by weight:

[0063] A method for preparing a high foaming rate hot melt adhesive, wherein the raw materials are prepared according to the above raw material composition, and the specific preparation steps are as follows: (1) Heat the reactor to 170°C.

[0064] (2) The above-mentioned tackifying resin, polyisobutylene and thermal oxidation stabilizer are sequentially added into the reactor heated in step (1), the temperature is maintained at 170° C., and stirred for 60 minutes until all the raw materials are completely melted and mixed.

[0065] (3) The functional polymer and polyolefin elastomer are added to the reactor of step (2), the temperature is maintained at 170°C, and stirred for 60 minutes until all the materials are completely melted and mixed evenly.

[0066] (4) The temperature of the material after being evenly mixed in step (3) is lowered to 140°C, the reaction kettle is sealed, and the reaction kettle is stirred and evacuated until there are no bubbles.

[0067] (5) The material obtained in step (4) is placed in a storage tank, and the valve is opened to allow the material to be discharged to an underwater pelletizer for molding to obtain a hot melt adhesive with a high foaming rate.

[0068] Example 3 A high foaming rate hot melt adhesive, the raw material composition of which is shown in the following table by weight:

[0069] A method for preparing a high foaming rate hot melt adhesive, wherein the raw materials are prepared according to the above raw material composition, and the specific preparation steps are as follows: (1) Heat the reactor to 180°C.

[0070] (2) The above-mentioned tackifying resin, polyisobutylene and thermal oxidation stabilizer are sequentially added into the reactor heated in step (1), the temperature is maintained at 180° C., and stirred for 40 minutes until all the raw materials are completely melted and mixed.

[0071] (3) The functional polymer and polyolefin elastomer are added to the reactor of step (2), the temperature is maintained at 180°C, and stirred for 70 minutes until all the materials are completely melted and mixed evenly.

[0072] (4) The temperature of the material after being evenly mixed in step (3) is lowered to 140°C, the reaction kettle is sealed, and the reaction kettle is stirred and evacuated until there are no bubbles.

[0073] (5) The material obtained in step (4) is placed in a storage tank, and the valve is opened to allow the material to be discharged to an underwater pelletizer for molding to obtain a hot melt adhesive with a high foaming rate.

[0074] Example 4 The method is basically the same as Example 1, except that the functional polymer is replaced by a copolymer of acrylic acid and ethylene, with the brand NUCREL 30907.

[0075] Example 5 It is basically the same as Example 1, except that the hydrogenated C5 petroleum resin is replaced by terpene resin.

[0076] Comparative Example 1 It is basically the same as Example 1, except that the functional polymer is replaced by the polyolefin elastomer in Example 1, that is, no functional polymer is added.

[0077] Comparative Example 2 It is basically the same as Example 1, except that the functional polymer is replaced by ionic polymer Surlyn resin 1601.

[0078] Comparative Example 3 It is basically the same as Example 1, except that the functional polymer is replaced by polyethylene graft (grafted monomer MAH), with the brand CMG5805.

[0079] Test Case In the present invention, the test method of the foaming rate is: use a disposable paper cup, remove the skin of the electronic scale (remove the weight of the paper cup), take a full cup of glue (unfoamed), and the weight is V. Then adjust the foaming, take a full cup of foamed glue, and weigh it as W (also remove the weight of the paper cup). Then the foaming rate = (1-W / v) × 100%.

[0080] The remaining performance indicators are implemented in accordance with the national standards commonly used in this field.

[0081] The test results of the above embodiments and comparative examples are as follows:

[0082] It can be seen from the above results that the hot melt adhesive containing a functional polymer with a specific structure provided by the present invention has a high foaming rate, tensile strength and metal peeling force, and is more suitable for use in folded corner seam sealing compared to other commonly used polymers as additives.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high foaming rate hot melt adhesive, characterized in that: include: Polyolefin elastomer and functional polymer in a mass ratio of 40-90:1-10; The functional polymer is a copolymer of a first monomer and a second monomer; the content of the second monomer in the functional polymer is 1-30%; The first monomer is selected from one or a combination of two or more of ethylene monomer, propylene monomer, butene monomer, hexene monomer and octene monomer; The second monomer is selected from one or a combination of two or more of maleic anhydride, acrylic acid and acrylic acid derivatives.

2. The high foaming rate hot melt adhesive according to claim 1, characterized in that: The acrylic acid derivative is selected from one or a combination of two or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate and glycidyl methacrylate.

3. The high foaming rate hot melt adhesive according to claim 1 or 2, characterized in that: Also includes: Tackifying resin; the mass ratio of the polyolefin elastomer to the tackifying resin is 40~90:5~40; Preferably, the tackifying resin is selected from one or a combination of two or more of rosin resin, petroleum resin and terpene resin.

4. The high foaming rate hot melt adhesive according to claim 3, characterized in that: The petroleum resin is selected from one or a combination of two or more of C5 petroleum resin, hydrogenated C5 petroleum resin, C9 petroleum resin and hydrogenated C9 petroleum resin.

5. The high foaming rate hot melt adhesive according to any one of claims 1 to 4, characterized in that: It also includes polyisobutylene; the mass ratio of the polyolefin elastomer to the polyisobutylene is 40~90: 1~20.

6. The high foaming rate hot melt adhesive according to any one of claims 1 to 5, characterized in that: It also includes a heat-oxidation stabilizer; the mass ratio of the polyolefin elastomer to the heat-oxidation stabilizer is 40-90:0.1-1; Preferably, the thermal oxidation stabilizer is a hindered phenol antioxidant and / or a phosphite antioxidant.

7. The high foaming rate hot melt adhesive according to any one of claims 1 to 6, characterized in that: The basic monomer constituting the polyolefin elastomer is ethylene.

8. The method for preparing the high foaming rate hot melt adhesive according to any one of claims 1 to 7, characterized in that: The high foaming rate hot melt adhesive is obtained by melting and mixing the raw materials and then molding them; preferably, the temperature of the melting and mixing is 140-200°C.

9. Use of the high foaming rate hot melt adhesive according to any one of claims 1 to 7 or the high foaming rate hot melt adhesive prepared by the preparation method according to claim 8 in sealing corner seams.

10. A sheet material with a folded corner seam, characterized in that: The folded corner seam sealing adopts the high foaming rate hot melt adhesive described in any one of claims 1 to 7 or the high foaming rate hot melt adhesive prepared by the preparation method described in claim 8.

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