Production process and production system of PUR (Polyurethane) hot melt adhesive

Abstract

The invention relates to the technical field of polyurethane material preparation, in particular to a PUR hot melt adhesive production process and a production system thereof.The production process includes the following steps that S1, polyol and isocyanate are put into a first reaction kettle to be preheated and stirred for a pre-reaction, and a prepolymer is obtained; and S2, continuing to add the PPC-co-PBT chain extender and the catalyst, heating, continuing to stir for reaction, and filtering and drying to obtain the PUR hot melt adhesive. The PUR hot melt adhesive prepared by the invention can effectively improve the bonding force at the initial stage of curing, not only shortens the curing time, but also ensures that a bonded part can be kept stable even in a dry or low-humidity environment, and avoids the phenomenon of displacement or falling off, thereby greatly improving the bonding effect.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane material preparation, and in particular to a production process and a production system of a PUR hot melt adhesive. Background Art

[0002] PUR hot melt adhesive is a moisture-curing reactive polyurethane hot melt adhesive. It uses isocyanate and polyol as the main raw materials. It has adjustable bonding properties and toughness (elasticity), and has excellent bonding strength, temperature resistance, chemical corrosion resistance and excellent aging resistance. PUR hot melt adhesive is heated and melted into a fluid state under controlled chemical inhibition conditions, which is convenient for coating operations; after the bonded materials are attached and cooled, the adhesive layer solidifies to achieve initial bonding. Subsequently, the adhesive layer reacts with moisture in the air and the attached moisture on the surface of the adherend, forming a high-polymer polymer through a chain extension process, which significantly improves the bonding strength, heat resistance and low temperature resistance. The molecular structure of PUR adhesive contains polar and chemically active urethane groups (-NHCOO-) or isocyanate groups (-NCO), which enable it to form a strong bond with a variety of materials containing active hydrogen, including new energy materials, lithium battery components, photovoltaic products, food packaging materials, wood, leather, textiles, paper, ceramics and other porous media.

[0003] In the prior art, the bonding strength of PUR hot melt adhesive is relatively weak in the initial stage of curing, especially in dry or low humidity environment, the curing speed will be significantly slowed down, causing the bonded parts to shift or fall off before curing is completed, affecting the bonding effect. In addition, PUR hot melt adhesive has good bonding performance for a variety of materials, but for non-polar materials (such as PP, PE, etc.), its bonding effect is not ideal. Summary of the invention

[0004] In order to solve the problems mentioned in the above background technology, the present invention provides a production process and a production system of PUR hot melt adhesive.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A production process of PUR hot melt adhesive comprises the following steps:

[0007] S1, putting polyol and isocyanate into a first reaction kettle for preheating, stirring for pre-reaction, and obtaining a prepolymer;

[0008] S2. Continue to add PPC-co-PBT chain extender and catalyst, open the third condenser, heat and continue to stir the reaction, and obtain PUR hot melt adhesive after filtering and drying.

[0009] Further, the isocyanate includes one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI).

[0010] Further, the polyol is a polyether polyol and / or a polyester polyol, the polyether polyol includes one or more of polyoxypropylene glycol, polytetrahydrofuran diol and tetrahydrofuran-oxypropylene copolymer glycol, and the polyester polyol comprises the following steps:

[0011] First, nitrogen is blown into the reactor as a protective gas, and phthalic anhydride, dibasic acid and catalyst are put into the second reactor through the manhole by crane. Then diol is pumped into the second reactor. The reaction is carried out under normal pressure. The stirrer in the second reactor is turned on, and heating is carried out while stirring. The reaction temperature is controlled at 130-140℃ by using a thermal oil furnace. The water and other volatile gases produced in the reaction enter the distillation tower through the pipeline. The cooling water reflux valve of the first condenser connected to the distillation tower is opened to control the temperature of the top of the distillation tower to 100-10 8℃, the water produced by the reaction is evaporated through the distillation tower and then condensed and discharged, the other substances in the distillation tower are refluxed to the reactor, the alcohol gas is refluxed to the second reactor after condensation, after the reaction for 1-2h, the temperature at the top of the distillation tower begins to drop, most of the condensation water produced by the reaction has been separated, the reaction is over, and the temperature of the second reactor is raised to 230-240℃, kept at a constant temperature for 2-3h, the alcohol is evaporated, the second condenser is opened to cool and recover the diol to the storage tank, and after the product specifications are analyzed and qualified, the alcohol recovered in the recovery tank is recycled and used in the next production.

[0012] Furthermore, the catalyst includes an organic tin catalyst or an organic amine catalyst, the organic tin catalyst includes one or more of dibutyltin dilaurate, dibutyltin diacetate and dioctyldistannoxane, and the organic amine catalyst includes one or more of triethylamine, N,N-dimethylcyclohexylamine and N,N-dimethylbenzylamine.

[0013] Further, the PPC-co-PBT chain extender is prepared by the following steps:

[0014] Put lactide, dimethyl terephthalate and 1,4-butanediol into the third reaction kettle, add bismuth isooctanoate under inert gas, stir and react until the viscosity of the system increases significantly and no obvious bubbles are generated, then stop heating and stirring, filter and separate to obtain a crude copolymer, add the crude copolymer into dimethyl sulfoxide, distill, wash with ethanol several times, and dry to obtain a PPC-co-PBT chain extender.

[0015] Furthermore, the feed mass ratio of polyol, isocyanate, PPC-co-PBT chain extender and catalyst is (13-14):(6-7):(0.008-0.01):(0.006-0.007).

[0016] Furthermore, the preheating temperature is 70-80°C, the stirring speed is 40-60rpm, and the pre-reaction time is 1-2h; the heating temperature is 80-90°C, the stirring speed is 60-100rpm, and the reaction time is 9-12h.

[0017] Furthermore, the dibasic acid is adipic acid and terephthalic acid, the diol is 1,4-butanediol and ethylene glycol, the catalyst is tin dioxide, and the feed mass ratio of phthalic anhydride, dibasic acid, diol and catalyst is (18-20):(10-11):(5-6):(0.001-0.005).

[0018] Furthermore, the reaction temperature is 180-200° C., the stirring speed is 100-200 rpm, the reaction time is 3-4 h, and the feed mass ratio of lactide, dimethyl terephthalate, 1,4-butanediol and bismuth isooctanoate is (4-6): (5-7): (3-5): (0.001-0.01).

[0019] According to another aspect of the present invention, a PUR hot melt adhesive production system is provided, comprising a polyester polyol production system, a chain extender production system and a hot melt adhesive production system, comprising:

[0020] The polyester polyol production system comprises a second reactor, a distillation tower, a first condenser, a second condenser and post-processing equipment, the second reactor is connected to the distillation tower in sequence, the distillation tower is fixedly connected to the first condenser, and the second reactor is fixedly connected to the second condenser;

[0021] The chain extender production system includes a third reactor, a distillation tower and post-processing equipment, and the third reactor is connected to the distillation tower in sequence;

[0022] The hot melt adhesive production system comprises a first reaction kettle, a third condenser and a filter. The first reaction kettle is fixedly connected to the third condenser, and the first reaction kettle is sequentially connected to the filter.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. In this technical solution, lactide undergoes ring-opening polymerization under the action of a catalyst to form a segment of polypropylene carbonate (PPC); at the same time, dimethyl terephthalate and 1,4-butanediol undergo an esterification reaction to form a segment of polybutylene terephthalate (PBT). The two segments will grow alternately during the copolymerization process, and eventually form a PPC-co-PBT copolymer. The addition of a chain extender can effectively increase the molecular chain length and cross-linking density of the PUR hot melt adhesive, so that the adhesive can form more physical and chemical cross-linking points in the early stage of curing, thereby improving the bonding strength. Even in a dry or low-humidity environment, due to the enhancement of the cross-linking structure, the adhesive can maintain good bonding performance and reduce the risk of component displacement or falling off.

[0025] 2. In this technical solution, the polypropylene carbonate (PPC) segment in the PPC-co-PBT chain extender has good reactivity and can promote the curing reaction of the PUR hot melt adhesive. At the same time, the polybutylene terephthalate (PBT) segment can provide good thermal stability and mechanical properties. The synergistic effect of the two segments allows the adhesive to cure quickly at a lower temperature, thereby improving production efficiency.

[0026] 3. The bonding effect of traditional PUR hot melt adhesive on non-polar materials is not ideal, mainly because the surface energy of the material is low and it is difficult to form an effective chemical bond with the adhesive. Through the chain extension reaction, the molecular chain of PUR hot melt adhesive is extended to form a tighter and stronger cross-linked structure. The PBT segment contains polar groups such as benzene rings, which can increase the compatibility and interaction between the adhesive and non-polar materials. In addition, the flexibility of the PPC segment can also adapt to slight changes in the surface of non-polar materials, further improving the bonding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The process flow chart of preparing polyester polyol in the present invention is as follows;

[0029] Figure 2 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 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.

[0031] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0032] Preparation Example 1

[0033] Polyester polyols are prepared by the following steps:

[0034] 180kg of phthalic anhydride, 40kg of adipic acid, 60kg of terephthalic acid, 25kg of 1,4-butanediol, 25kg of ethylene glycol and 0.01kg of tin dioxide were put into the second reactor and heated to 130°C with stirring at a speed of 80rpm. The cooling water reflux valve of the first condenser connected to the distillation tower was opened, and the temperature of the top of the distillation tower was controlled to be 100°C. The reaction was carried out for 1h, and then the temperature of the second reactor was raised to 230°C and kept at a constant temperature for 2h. The second condenser was opened to cool and recover the diol, and the product was stored for later use.

[0035] Preparation Example 2

[0036] Polyester polyols are prepared by the following steps:

[0037] 18.5 kg of phthalic anhydride, 40 kg of adipic acid, 65 kg of terephthalic acid, 25 kg of 1,4-butanediol, 33.5 kg of ethylene glycol and 0.02 kg of tin dioxide were put into the second reactor and heated to 135°C with stirring at a speed of 90 rpm. The cooling water reflux valve of the first condenser connected to the distillation tower was opened, and the temperature of the top of the distillation tower was controlled to be 102°C. The reaction was carried out for 1.5 hours, and then the temperature of the second reactor was raised to 235°C and kept at a constant temperature for 2.5 hours. The second condenser was opened to cool and recover the diol, and the product was stored for later use.

[0038] Preparation Example 3

[0039] Polyester polyols are prepared by the following steps:

[0040] 200kg of phthalic anhydride, 40kg of adipic acid, 70kg of terephthalic acid, 25kg of 1,4-butanediol, 35kg of ethylene glycol and 0.05kg of tin dioxide were put into the second reactor and heated to 140°C with stirring at a speed of 100rpm. The cooling water reflux valve of the first condenser connected to the distillation tower was opened, and the temperature of the top of the distillation tower was controlled to be 108°C. The reaction was carried out for 2h, and then the temperature of the second reactor was raised to 240°C and kept at a constant temperature for 3h. The second condenser was opened to cool and recover the diol, and the product was stored for later use.

[0041] Preparation Example 4

[0042] The PPC-co-PBT chain extender is prepared by the following steps:

[0043] 4 kg of lactide, 5 kg of dimethyl terephthalate and 3 kg of 1,4-butanediol were put into the third reactor, and 0.001 kg of bismuth isooctanoate was added under inert gas. The reaction was stirred for 3 hours at a temperature of 180 ° C and a stirring speed of 100 rpm. The crude copolymer was separated by filtration to obtain an excess amount (about twice the mass of the crude product) of dimethyl sulfoxide, distilled, washed with ethanol several times, and dried to obtain a PPC-co-PBT chain extender.

[0044] Preparation Example 5

[0045] The PPC-co-PBT chain extender is prepared by the following steps:

[0046] 5.5 kg of lactide, 6.5 kg of dimethyl terephthalate and 4 kg of 1,4-butanediol were put into the third reactor, and 0.006 kg of bismuth isooctanoate was added under inert gas. The reaction was stirred for 3.5 hours at a reaction temperature of 190 ° C and a stirring speed of 150 rpm. The crude copolymer was separated by filtration to obtain an excess amount (about twice the mass of the crude product) of dimethyl sulfoxide, distilled, washed with ethanol several times, and dried to obtain a PPC-co-PBT chain extender.

[0047] Preparation Example 6

[0048] The PPC-co-PBT chain extender is prepared by the following steps:

[0049] 6 kg of lactide, 7 kg of dimethyl terephthalate and 5 kg of 1,4-butanediol were put into the third reactor, and 0.01 kg of bismuth isooctanoate was added under inert gas. The reaction was stirred for 4 hours at a temperature of 200 ° C and a stirring speed of 200 rpm. The crude copolymer was separated by filtration to obtain an excess amount of dimethyl sulfoxide (about twice the mass of the crude product), distilled, washed with ethanol several times, and dried to obtain a PPC-co-PBT chain extender.

[0050] Example 1

[0051] A production process of PUR hot melt adhesive comprises the following steps:

[0052] 60 kg of polyoxypropylene glycol, 70 kg of polyester polyol obtained in Preparation Example 1, 45 kg of MDI and 15 kg of TDI were placed in a first reaction kettle and preheated to 70-80° C., and stirred at a speed of 40-60 rpm for pre-reaction for 1-2 hours to obtain a prepolymer;

[0053] 0.008 kg of the PPC-co-PBT chain extender prepared in Preparation Example 4 and 0.006 kg of dibutyltin dilaurate were added, the mixture was heated to 80° C., and the reaction was continued with stirring at 60 rpm for 9 hours. After filtering and drying, a PUR hot melt adhesive was obtained.

[0054] Example 2

[0055] A production process of PUR hot melt adhesive comprises the following steps:

[0056] 62 kg of polyoxypropylene glycol, 70 kg of polyester polyol obtained in Preparation Example 2, 85 kg of MDI and 15 kg of TDI were placed in a first reaction kettle and preheated to 75° C. The mixture was stirred at a speed of 50 rpm for a pre-reaction of 1.5 h to obtain a prepolymer;

[0057] Continue to add 0.009 kg of the PPC-co-PBT chain extender prepared in Preparation Example 5 and 0.007 kg of dibutyltin diacetate, heat to 85° C., continue to stir the reaction at a speed of 80 rpm for 10 hours, filter and dry to obtain PUR hot melt adhesive.

[0058] Example 3

[0059] A production process of PUR hot melt adhesive comprises the following steps:

[0060] 70 kg of polyoxypropylene glycol, 70 kg of polyester polyol obtained in Preparation Example 3, 55 kg of MDI and 15 kg of TDI were put into a first reaction kettle and preheated to 80° C., and stirred at a speed of 60 rpm for pre-reaction for 2 hours to obtain a prepolymer;

[0061] Continue to add 0.01 kg of the PPC-co-PBT chain extender prepared in Preparation Example 6 and 0.007 kg of N, N-dimethylcyclohexylamine, heat to 90°C, continue to stir the reaction at a speed of 100 rpm for 12 hours, filter and dry to obtain PUR hot melt adhesive.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that polypropylene carbonate (PPC) is added as a chain extender, and the remaining steps are the same as those in Example 1.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 2 is that polybutylene terephthalate (PBT) is added as a chain extender, and the remaining steps are the same as those in Example 2.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 3 is that no chain extender is added, and the remaining steps are the same as those in Example 3.

[0068] The PUR hot melt adhesive samples prepared in Examples 1-3 and Comparative Examples 1-3 were uniformly coated on the test substrates of polar material (glass sheet, size 100mm x 25mm) and non-polar material (PP sheet size 100mm x 25mm), respectively, with a coating thickness of 0.2mm±0.02mm to form an adhesive layer. The coated samples were placed in an oven, and the curing temperature was set to 80°C and the humidity was set to 30%.

[0069] (Ⅰ) Initial adhesion test:

[0070] At the initial stage of curing (1 hour after the start of curing), use a viscometer to test the adhesion between the adhesive layer and the substrate. Hang the standard weight of the viscometer on the test probe, gently touch the probe to the adhesive layer, then pull it up vertically, and record the pulling force as the initial adhesion.

[0071] (II) Final bonding strength test:

[0072] Referring to GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)", each sample was clamped in the standard fixture of the tensile testing machine, and the sample was stretched at a speed of 5mm / min until the sample broke, and the tensile shear strength was calculated. The results are shown in Table 1:

[0073] Table 1. Test results of Examples 1-3 and Comparative Examples 1-3

[0074] serial number Initial adhesion (N) Tensile shear strength (MPa) Example 1 52 11.2 Example 2 56 13.5 Example 3 54 10.3 Comparative Example 1 31 8.2 Comparative Example 2 28 6.3 Comparative Example 3 25 5.7

[0075] As shown in Table 1, the initial bonding forces of Examples 1-3 are relatively high, ranging from 52N to 56N, which may be due to the addition of the PPC-co-PBT chain extender, which enhances the interaction between the PUR hot melt adhesive and the substrate and improves the initial bonding adhesion. The initial bonding forces of Comparative Examples 1-3 are relatively low, especially Comparative Example 3 (without the addition of the chain extender) has the lowest initial bonding force of only 25N, indicating that the lack or inappropriateness of the chain extender may lead to a weakening of the interaction between the PUR hot melt adhesive and the substrate.

[0076] The final bonding strengths of Examples 1-3 are relatively high, all between 10.3MPa and 13.5MPa. The chain extender may enhance the bonding strength by improving the molecular structure of the PUR hot melt adhesive and improving its compatibility with the substrate. In Comparative Example 1, polypropylene carbonate (PPC) was added as a chain extender, but the tensile shear strength was relatively low (8.2MPa), which may be because the compatibility of PPC with PUR hot melt adhesive is not as good as that of PPC-co-PBT chain extender, resulting in a decrease in bonding performance. In Comparative Example 2, polybutylene terephthalate (PBT) was added as a chain extender, and the tensile shear strength was also relatively low (6.3MPa). Comparative Example 3 did not add a chain extender, and the tensile shear strength was the lowest (5.7MPa).

[0077] The PPC-co-PBT chain extender may contain both a part that is compatible with the PUR hot melt adhesive (such as a polycarbonate segment) and a part that interacts with a polar substrate (such as glass) or a non-polar substrate (such as PP) (such as a terephthalate segment) due to its special molecular structure. This synergistic effect enables the PPC-co-PBT chain extender to effectively enhance the bonding performance between the PUR hot melt adhesive and the substrate. The better the compatibility of the chain extender with the PUR hot melt adhesive, the more evenly it can be dispersed in the PUR hot melt adhesive, thereby more effectively playing its role in enhancing the bonding performance. The PPC-co-PBT chain extender has good compatibility because it has a similar segment structure to the PUR hot melt adhesive. In addition, the functional groups in the chain extender (such as the ester group in terephthalate) may interact with the functional groups on the surface of the substrate, thereby enhancing the bonding strength between the PUR hot melt adhesive and the substrate.

[0078] In summary, the addition of PPC-co-PBT chain extender significantly improves the initial bonding force and final bonding strength of PUR hot melt adhesive. Therefore, the PUR hot melt adhesive prepared in Examples 1-3 can effectively improve the bonding force in the initial curing stage, which not only shortens the curing time, but also ensures that the bonded parts remain stable even in a dry or low humidity environment, avoiding displacement or falling off, thereby greatly improving the bonding effect.

[0079] In the description of the specification, the description with reference to the terms "preparation example", "embodiment", "various embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or preparation example are included in at least one embodiment or preparation example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or preparation example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or preparation examples in a suitable manner.

[0080] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A production process of PUR hot melt adhesive, characterized in that: The following steps are involved: S1, putting polyol and isocyanate into a first reaction kettle for preheating, stirring for pre-reaction, and obtaining a prepolymer; S2. Continue to add PPC-co-PBT chain extender and catalyst, heat and continue to stir the reaction, filter and dry to obtain PUR hot melt adhesive.

2. A production process of PUR hot melt adhesive according to claim 1, characterized in that: The isocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

3. The production process of a PUR hot melt adhesive according to claim 1, characterized in that: The polyol is a polyether polyol and / or a polyester polyol, wherein the polyether polyol comprises one or more of polyoxypropylene glycol, polytetrahydrofuran diol and tetrahydrofuran-oxypropylene copolymer glycol, and the polyester polyol comprises the following steps to prepare: Put phthalic anhydride, dibasic acid, diol and catalyst into the second reactor, heat to 130-140°C with stirring at a speed of 80-100rpm, open the cooling water reflux valve of the first condenser connected to the distillation tower, control the temperature of the top of the distillation tower to 100-108°C, react for 1-2h, then raise the temperature of the second reactor to 230-240°C, keep the temperature constant for 2-3h, open the second condenser to cool and recover the diol, and store the product for later use.

4. The production process of a PUR hot melt adhesive according to claim 1, characterized in that: The catalyst includes an organic tin catalyst or an organic amine catalyst. The organic tin catalyst includes one or more of dibutyltin dilaurate, dibutyltin diacetate and dioctyldistannoxane. The organic amine catalyst includes one or more of triethylamine, N,N-dimethylcyclohexylamine and N,N-dimethylbenzylamine.

5. The production process of a PUR hot melt adhesive according to claim 1, characterized in that: The PPC-co-PBT chain extender is prepared by the following steps: Put lactide, dimethyl terephthalate and 1,4-butanediol into the third reaction kettle, add bismuth isooctanoate under inert gas, stir to react, filter and separate to obtain a crude copolymer, add the crude copolymer into dimethyl sulfoxide, distill, wash with ethanol several times, and dry to obtain a PPC-co-PBT chain extender.

6. The production process of a PUR hot melt adhesive according to claim 1, characterized in that: The feed mass ratio of polyol, isocyanate, PPC-co-PBT chain extender and catalyst is (13-14):(6-7):(0.008-0.01):(0.006-0.007).

7. The production process of a PUR hot melt adhesive according to claim 1, characterized in that: The preheating temperature is 70-80°C, the stirring speed is 40-60rpm, and the pre-reaction time is 1-2h; the heating temperature is 80-90°C, the stirring speed is 60-100rpm, and the reaction time is 9-12h.

8. The production process of a PUR hot melt adhesive according to claim 3, characterized in that: The dibasic acids are adipic acid and terephthalic acid, the diols are 1,4-butanediol and ethylene glycol, the catalyst is tin dioxide, and the feed mass ratio of phthalic anhydride, dibasic acid, diol and catalyst is (18-20):(10-11):(5-6):(0.001-0.005).

9. The production process of a PUR hot melt adhesive according to claim 5, characterized in that: The reaction temperature is 180-200° C., the stirring speed is 100-200 rpm, the reaction time is 3-4 hours, and the feed mass ratio of lactide, dimethyl terephthalate, 1,4-butanediol and bismuth isooctanoate is (4-6): (5-7): (3-5): (0.001-0.01).

10. A production system for producing PUR hot melt adhesive according to any one of claims 1 to 9, comprising a polyester polyol production system, a chain extender production system and a hot melt adhesive production system, characterized in that: include: The polyester polyol production system comprises a second reactor, a distillation tower, a first condenser, a second condenser and post-processing equipment, the second reactor is connected to the distillation tower in sequence, the distillation tower is fixedly connected to the first condenser, and the second reactor is fixedly connected to the second condenser; The chain extender production system includes a third reactor, a distillation tower and post-processing equipment, and the third reactor is connected to the distillation tower in sequence; The hot melt adhesive production system comprises a first reaction kettle, a third condenser and a filter. The first reaction kettle is fixedly connected to the third condenser, and the first reaction kettle is sequentially connected to the filter.

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