Polyurethane hot melt adhesive for shoes and manufacturing process of polyurethane hot melt adhesive

Abstract

The invention discloses a polyurethane hot melt adhesive for shoes and a manufacturing process of the polyurethane hot melt adhesive, and relates to the technical field of manufacturing of hot melt adhesives. The polyurethane hot melt adhesive for the shoes is prepared from the following components in parts by weight: 50 to 70 parts of polyester polyol, 2 to 10 parts of dimer acid modified polyol, 5 to 15 parts of tackifying resin, 5 to 10 parts of thermoplastic resin, 0.1 to 0.5 part of antioxidant and 0 to 19 parts of isocyanate, 0 to 19 parts of isocyanate, 0.2 to 0.5 part of a coupling agent and 0.1 to 0.5 part of a catalyst. According to the polyurethane hot melt adhesive for the shoes and the manufacturing process of the polyurethane hot melt adhesive, in the process of preparing the polyurethane hot melt adhesive, the yellowing resistance of the polyurethane hot melt adhesive is improved by selecting various isocyanates, the initial viscosity of the polyurethane hot melt adhesive is effectively enhanced by virtue of the two-step dosage design of the isocyanates, and in addition, the polyurethane hot melt adhesive has the advantages that the yellowing resistance of the polyurethane hot melt adhesive is improved; by selecting the combination of different types of polyester polyol, tackifying resin and thermoplastic resin, the initial adhesion strength and the adhesion force to a base material are remarkably improved, heat waste can be avoided, and the reaction efficiency and effect are improved.

Description

Technical Field

[0001] The invention relates to the technical field of hot melt adhesive manufacturing, in particular to polyurethane hot melt adhesive for shoes and a manufacturing process thereof. Background Art

[0002] As a key material, footwear adhesives are becoming increasingly important. Different shoe materials, such as rubber, TPR, EVA foam, and various types of synthetic leather, vary in surface polarity and chemical properties, requiring the use of cleaners and treatments to optimize surface properties for effective bonding. Currently, mainstream adhesives on the market include solvent-based, water-based, and hot-melt types. However, in practice, existing adhesives exhibit significant shortcomings in initial adhesion and yellowing resistance, making them difficult to meet the demands of high-end footwear manufacturing.

[0003] While solvent-based adhesives are widely used due to their excellent solubility and permeability, the solvent volatilization process can slow the initial adhesion of the adhesive layer during curing. This is particularly problematic when rapidly bonding low-surface-energy shoe materials like EVA / TPR and EVA / EVA. This lack of initial adhesion can often lead to lamination deviations due to inaccurate positioning, severely impacting production line efficiency. Furthermore, the yellowing resistance of solvent-based adhesives is limited by the stability of the chemical groups in the formula. With long-term storage or exposure to light, the adhesive layer is prone to oxidation and discoloration, making it difficult to meet the high-quality appearance requirements of light-colored shoe materials.

[0004] Water-based adhesives use water as a dispersion medium, which avoids the problem of solvent volatilization. However, their drying process, which relies on heating or airing, is time-consuming and labor-intensive, and has strict requirements on the polarity of the shoe material. When working with non-polar or low-polarity shoe materials, initial adhesion is poor due to a lack of effective interfacial chemistry, often requiring additional surface treatment steps and increasing production costs. Furthermore, residual moisture in water-based systems can cause microbubbles within the adhesive layer, reducing interfacial bonding density and further exacerbating the deterioration of yellowing resistance.

[0005] Pressure-sensitive products in hot-melt adhesives do not contain reactive groups and rely solely on physical adhesion. They are prone to melting and flowing in high-temperature environments, resulting in a sudden drop in initial adhesion, which cannot meet the immediate shaping requirements after shoe materials are bonded. Although reactive polyurethane hot-melt adhesives contain active isocyanates and can form chemical bonds with active hydrogen-containing substrates, their existing formulas are limited in the reaction rate of isocyanate groups in low-temperature construction or rapid curing scenarios, and the effect of improving initial adhesion is not significant. Especially for foaming materials with weak polarity such as EVA, the initial contact bonding strength of existing reactive hot-melt adhesives is insufficient, requiring additional pressure or extended pressure holding time, which restricts the efficiency of automated production. At the same time, the catalysts or additives used in some reactive hot-melt adhesive formulas are prone to molecular structure degradation under light, resulting in an increase in the yellowing index of the adhesive layer and failure to pass weather resistance tests.

[0006] In summary, existing shoe adhesives, when used in typical shoe material bonding scenarios such as EVA / TPR composites and EVA self-adhesives, generally face technical bottlenecks such as insufficient initial adhesion to support rapid processing and yellowing resistance that fails to meet long-term appearance requirements.

[0007] Moreover, during production, a reactor is required to heat and stir the materials. The reactor mainly comprises a reactor body and a jacket. The heating operation of the materials is achieved by circulating the heat transfer oil in the jacket. However, it is not convenient to adjust the height of the heat transfer oil in the jacket according to the height of the materials in the reactor body. If the height of the heat transfer oil is higher than the height of the materials, it is easy to cause heat waste. At the same time, when heating is not required, it is not convenient to recycle and store the heat transfer oil in the jacket, which will also cause heat waste and is not energy-saving and environmentally friendly. Moreover, when materials are added later, it is not only easy to adhere to the stirring blades, but also affects the reaction temperature, thereby affecting the efficiency and effect of the reaction. Summary of the Invention

[0008] The object of the present invention is to provide a polyurethane hot melt adhesive for shoes and a manufacturing process thereof, so as to solve the problems raised in the above background technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a polyurethane hot melt adhesive for shoes, comprising the following components in parts by weight: 50-70 parts of polyester polyol, 2-10 parts of dimer acid-modified polyol, 5-15 parts of tackifying resin, 5-10 parts of thermoplastic resin, 0.1-0.5 parts of antioxidant, 0-19 parts of isocyanate; 0-19 parts of isocyanate, 0.2-0.5 parts of coupling agent, and 0.1-0.5 parts of catalyst.

[0010] Preferably, the polyester polyol model is any one or more of Evonik 7250, Evonik 7360, Evonik 7361, Evonik 7380, Evonik 7150, and Asahikawa Chemical XCP-PA110N, the dimer acid-modified polyol is any one or more of DA-21, DA-2026, and DA-3190 of Shanghai Jingri Chemical, and the thermoplastic resin is any one or more of acrylic resin, saturated polyester resin, TPU resin, EVA resin, or polyolefin resin.

[0011] Preferably, the antioxidant is any one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester and tris[2,4-di-tert-butylphenyl]phosphite; the isocyanate is any one or more of diisocyanate diphenylmethane diisocyanate, isophorone diisocyanate, and carbodiimide-modified diphenylmethyl diisocyanate; the coupling agent is any one or more of silane coupling agents γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane; and the catalyst is any one or more of dibutyltin dilaurate, stannous octoate, triethyleneamine, and dimorpholine diethyl ether.

[0012] A manufacturing process of polyurethane hot melt adhesive for shoes comprises the following steps:

[0013] S1: Weigh the corresponding fractional weights of raw materials, add polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin, and antioxidant into a reaction apparatus, heat to 135-140°C, and vacuum dehydrate at 250 rpm for 2 hours;

[0014] S2: Cool to 120°C, add isocyanate IPDI to the reaction apparatus, and react at 130-135°C for 1.5 h at a stirring speed of 350 r / min under vacuum conditions;

[0015] S3: Cool to 120°C, continue to add isocyanate MDI-100 to the reaction apparatus, heat to 135°C, add coupling agent and catalyst, and react at a stirring speed of 350 r / min under vacuum conditions for 1.5 hours;

[0016] S4: After stirring for 0.5 h under vacuum conditions, the material is discharged and then placed into an aluminum foil bag. The air is replaced with nitrogen and then sealed for storage;

[0017] The reaction device includes a bottom plate and a reactor body, the reactor body includes a reactor body and a hollow jacket, and a discharge valve is provided at the bottom of the reactor body, a first feed valve and a second feed valve are provided on the top of the reactor body, and a vacuum pump is provided on the top of the reactor body, the top of the reactor body is connected to a plurality of stirring blades through a stirring rod, the top of the bottom plate is connected to an insulation box through a lifting mechanism, and the top of the bottom plate is fixedly connected to a circulation pump, an oil supply pipe is fixedly connected between the circulation pump and the jacket, and an oil return pipe is fixedly connected between the jacket and the insulation box, an oil extraction pipe is fixedly connected between the circulation pump and the insulation box, and an electric heater is provided on the side wall of the oil supply pipe, an annular groove is provided on the top of the jacket, and a movable ring is connected in the annular groove through a lifting module, a vent valve is fixedly inserted on the top of the movable ring, and a preheating mechanism for preheating the added material is provided at the lower end of the second feed valve, and the rotation of the stirring rod is driven by a driving mechanism.

[0018] Preferably, the lifting mechanism includes a guide rail fixedly connected to the top of the base plate, and a push plate is slidably connected to the guide rail, the side wall of the push plate is provided with a first inclined surface and a second inclined surface, and the top of the movable ring is fixedly connected with an L-shaped push rod, the side wall of the insulated box is fixedly connected to two symmetrically arranged connecting blocks, and a T-shaped guide rod is inserted into the top of each connecting block, the lower end of the T-shaped guide rod is fixed to the top of the base plate, and the side wall of each T-shaped guide rod is sleeved with a first spring.

[0019] Preferably, the preheating mechanism includes a preheating box fixedly connected to the lower end of the second feed valve, and the side wall of the preheating box is fixedly sleeved with a hollow cover, the side wall of the hollow cover is fixedly connected to an annular tube, and a first connecting tube is fixedly connected between the annular tube and the oil supply pipe, a second connecting tube is fixedly connected between the hollow cover and the insulation box, the bottom of the preheating box is fixedly connected to a solenoid valve, and the other end of the solenoid valve is fixedly connected to the feed pipe, a cylindrical cavity is opened in the stirring rod, and a fixed plug is fixedly inserted into the side wall of the cylindrical cavity Fixed pipe, the other end of the fixed pipe is fixedly connected to an annular cover, and a rotating ring is rotatably connected inside the annular cover, the feed pipe is fixedly inserted into the side wall of the rotating ring, and a plurality of feed holes are provided on the side wall of the cylindrical cavity, a one-way valve is provided in the feed hole, and an extrusion mechanism is provided in the cylindrical cavity, the top of the preheating box is fixedly connected to the fixed box, and a circular hole is provided on the side wall of the fixed box, a filter is fixedly connected in the circular hole, a stirring mechanism is provided in the preheating box, and a scraping mechanism is provided on the side wall of the filter.

[0020] Preferably, the stirring mechanism includes a rotating rod rotatably connected to the preheating box, and a plurality of stirring plates arranged in an array are fixedly connected to the side wall of the rotating rod, and a turbine is fixedly connected to the end of the rotating rod near the annular tube outlet.

[0021] Preferably, the scraping mechanism includes a rotating shaft rotatably connected to a fixed box, and a plurality of scrapers arranged in an array are fixedly connected to the side wall of the rotating shaft, one end of the rotating shaft is fixedly connected to a driven pulley, and a driving pulley is fixedly provided on the side wall of the rotating rod, and the driving pulley and the driven pulley are transmitted by a belt.

[0022] Preferably, the extrusion mechanism includes an L-shaped plate fixedly connected to the top of the kettle body, and the top of the L-shaped plate is fixedly connected to a cylinder, the cylinder includes a piston rod, and the lower end of the piston rod passes through the cylindrical cavity and is fixedly connected to a piston.

[0023] Preferably, the driving mechanism includes a gear ring fixedly mounted on the side wall of the stirring rod, and a U-shaped plate is fixedly connected to the top of the kettle body, a motor is fixedly connected to the top of the U-shaped plate, a gear is fixedly connected to the output end of the motor, and the gear is meshed with the gear ring.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) This kind of polyurethane hot melt adhesive for shoes and its manufacturing process, by setting a lifting mechanism, etc., during the reaction, polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin, antioxidant are put into the kettle through the first feed valve, and then, according to the liquid level of the material, the lifting module drives the movable ring to move downward and adjust to ensure that it is consistent with the height of the material. At the same time, when the movable ring moves downward, it can drive the push rod to move downward synchronously. When the end of the push rod slides along the first inclined surface to the side wall of the push plate, it can push the push plate to move along the guide rail toward the connecting block, and make the second inclined surface abut against the side wall of the connecting block, so as to push the insulation box to move upward. At the same time, the first spring is compressed. At this time, the heat transfer oil temporarily stored in the insulation box can be filled into the jacket through the return oil pipe and the oil extraction pipe. Then, Start the circulation pump, so that the heat transfer oil in the insulation box enters the electric heater through the oil extraction pipe for heating, and after heating, enters the jacket through the oil supply pipe, and then returns to the insulation box again through the return oil pipe, so that the heat transfer oil in the jacket can be circulated, and the material is heated to -℃, and vacuum dehydrated under r / min stirring conditions for h, so that the height of the heat transfer oil in the jacket can be adjusted according to the height of the material to ensure that the heating height is the same as the height of the material, ensuring the heating effect while avoiding heat waste, which is more energy-saving and environmentally friendly. When the kettle body does not need to be heated, the moving ring is driven to move upward and reset through the lifting module. At this time, the insulation box can move downward and reset under the action of the first spring, so that the heat transfer oil in the jacket can return to the insulation box through the return oil pipe and the oil extraction pipe for temporary insulation storage, which avoids heat waste and is more energy-saving and environmentally friendly.

[0026] (2) This kind of polyurethane hot melt adhesive for shoes and its manufacturing process, by setting a preheating mechanism, etc., in step S and step S, when it is necessary to add the material isocyanate IPDI or isocyanate MDI-, first open the second feed valve to allow the material to enter the preheating box through the second feed valve. At this time, the heated heat transfer oil can enter the first connecting pipe through the oil supply pipe and enter the hollow cover through the annular pipe, and then return to the insulation box through the second connecting pipe. At this time, the material in the preheating box can be preheated. At the same time, when the heat transfer oil enters the hollow cover, it can impact the turbine, thereby driving the turbine to rotate. The rotation of the turbine drives the rotating rod and the stirring plate to rotate, which can automatically stir the material in the preheating box to ensure the efficiency and effect of heating. Moreover, when the rotating rod rotates, it can drive the active pulley to The driven pulley is driven to rotate by the belt at the same time. When the driven pulley rotates, the scraper can be driven to rotate by the rotating shaft. At this time, the powder adhering to the surface of the filter can be scraped and cleaned to avoid material waste while ensuring the vacuum effect. When heated to the reaction temperature, the solenoid valve is opened, and the material can enter the annular cover through the feed pipe, and then enter the cylindrical cavity through the fixed pipe. Then, the cylinder is started and the piston is driven by the piston rod to move downward, so that the material in the cylindrical cavity can be squeezed and enter the kettle body through the feed hole for reaction. Feeding at different heights can avoid the material adhering to the stirring blades while improving the efficiency and effect of stirring. Moreover, by preheating, the reaction temperature can be quickly reached, the overall reaction time can be shortened, and the efficiency and effect of the reaction can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a process flow chart of the present invention;

[0028] Figure 2 Schematic diagram of the overall structure of the reaction device in the present invention;

[0029] Figure 3 This is a schematic diagram of the overall structure of the reaction device of the present invention from another perspective;

[0030] Figure 4 It is a partial cross-sectional structural schematic diagram of the kettle body in the present invention;

[0031] Figure 5 It is a partial cross-sectional structural schematic diagram of the stirring rod in the present invention;

[0032] Figure 6 It is a partial cross-sectional structural diagram of the preheating box, the hollow cover and the annular tube in the present invention;

[0033] Figure 7 for Figure 3 Schematic diagram of the enlarged structure at A in the middle;

[0034] Figure 8 for Figure 5 Schematic diagram of the enlarged structure at B in the middle;

[0035] Figure 9 for Figure 6 Schematic diagram of the enlarged structure at C in the middle;

[0036] Figure 10 for Figure 9 Schematic diagram of the enlarged structure at point D in the middle.

[0037] In the figure: 1, bottom plate; 201, guide rail; 202, push plate; 203, first inclined surface; 204, push rod; 205, second inclined surface; 206, T-shaped guide rod; 207, connecting block; 208, first spring; 301, preheating box; 302, hollow cover; 303, first connecting pipe; 304, annular pipe; 305, second connecting pipe; 306, fixed box; 307, circular hole; 308, filter screen; 309, fixed pipe; 310, annular cover; 311, rotating ring; 312, feeding pipe; 313, solenoid valve; 314, cylindrical cavity; 315, feeding hole; 401, rotating rod; 402, stirring plate; 403, turbine; 501, rotating shaft; 5 02. Scraper; 503. Driven pulley; 504. Driving pulley; 505. Belt; 601. L-shaped plate; 602. Cylinder; 603. Piston rod; 604. Piston; 701. Ring gear; 702. U-shaped plate; 703. Motor; 704. Gear; 801. Kettle body; 802. Jacket; 803. First feed valve; 804. Vacuum pump; 805. Discharge valve; 806. Stirring rod; 807. Stirring blade; 808. Insulation box; 809. Circulation pump; 810. Oil supply pipe; 811. Electric heater; 812. Oil return pipe; 813. Oil extraction pipe; 814. Second feed valve; 9. Annular groove; 10. Lifting module; 11. Moving ring. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0039] See also Figures 1-10The present invention provides a polyurethane hot melt adhesive for shoes, comprising the following components in parts by weight: 50-70 parts of polyester polyol, 2-10 parts of dimer acid-modified polyol, 5-15 parts of tackifying resin, 5-10 parts of thermoplastic resin, 0.1-0.5 parts of antioxidant, 0-19 parts of isocyanate; 0-19 parts of isocyanate, 0.2-0.5 parts of coupling agent, and 0.1-0.5 parts of catalyst.

[0040] The polyester polyol model is any one or more of Evonik 7250, Evonik 7360, Evonik 7361, Evonik 7380, Evonik 7150, and Asahikawa Chemical XCP-PA110N; the dimer acid-modified polyol is any one or more of DA-21, DA-2026, and DA-3190 of Shanghai Jingri Chemical; and the thermoplastic resin is any one or more of acrylic resin, saturated polyester resin, TPU resin, EVA resin, or polyolefin resin.

[0041] The antioxidant is any one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester and tris[2,4-di-tert-butylphenyl]phosphite; the isocyanate is any one or more of diisocyanate diphenylmethane diisocyanate, isophorone diisocyanate, and carbodiimide-modified diphenylmethyl diisocyanate; the coupling agent is any one or more of silane coupling agents γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-mercaptopropyl Any one or more of triethoxysilane and γ-mercaptopropyltrimethoxysilane; the catalyst is any one or more of dibutyltin dilaurate, stannous octoate, triethyleneamine, and dimorpholine diethyl ether; in the process of preparing the polyurethane hot melt adhesive, the yellowing resistance of the polyurethane hot melt adhesive is improved by selecting a variety of isocyanates; the two-step dosage design of the isocyanate effectively enhances its initial adhesion; in addition, by selecting a combination of different types of polyester polyols, tackifying resins, and thermoplastic resins, the initial adhesion strength and the adhesion to the substrate are significantly improved.

[0042] A manufacturing process of polyurethane hot melt adhesive for shoes comprises the following steps:

[0043] S1: Weigh the corresponding fractional weights of raw materials, add polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin, and antioxidant into a reaction apparatus, heat to 135-140°C, and vacuum dehydrate at 250 rpm for 2 hours;

[0044] S2: Cool to 120°C, add isocyanate IPDI to the reaction apparatus, and react at 130-135°C for 1.5 h at a stirring speed of 350 r / min under vacuum conditions;

[0045] S3: Cool to 120°C, continue to add isocyanate MDI-100 to the reaction apparatus, heat to 135°C, add coupling agent and catalyst, and react at a stirring speed of 350 r / min under vacuum conditions for 1.5 hours;

[0046] S4: After stirring for 0.5 h under vacuum conditions, the material is discharged and then placed into an aluminum foil bag. The air is replaced with nitrogen and then sealed for storage;

[0047] The reaction device includes a bottom plate 1 and a reactor body, the reactor body includes a reactor body 801 and a hollow jacket 802, and a discharge valve 805 is provided at the bottom of the reactor body 801, a first feed valve 803 and a second feed valve 814 are provided at the top of the reactor body 801, and a vacuum pump 804 is provided at the top of the reactor body 801. The top of the reactor body 801 is connected to a plurality of stirring blades 807 by a stirring rod 806 for rotation, and the top of the bottom plate 1 is connected to an insulation box 801 through a lifting mechanism. 08, and a circulation pump 809 is fixedly connected to the top of the bottom plate 1, an oil supply pipe 810 is fixedly connected between the circulation pump 809 and the jacket 802, and an oil return pipe 812 is fixedly connected between the jacket 802 and the insulation box 808, an oil extraction pipe 813 is fixedly connected between the circulation pump 809 and the insulation box 808, and an electric heater 811 is provided on the side wall of the oil supply pipe 810, an annular groove 9 is opened on the top of the jacket 802, and a movable block 811 is connected to the annular groove 9 through the lifting module 10. The moving ring 11 and the top of the moving ring 11 are fixedly inserted with a vent valve 12, and the lower end of the second feed valve 814 is provided with a preheating mechanism for preheating the subsequently added materials. The second feed valve 814 and the preheating mechanism can be provided in two groups, which respectively preheat the two subsequently added materials, and the rotation of the stirring rod 806 is driven by the driving mechanism. During the reaction, it is convenient to adjust the height of the heat transfer oil in the jacket 802 according to the height of the material to ensure that the heating height is the same as the height of the material. When the kettle body 801 does not need to be heated, the heat transfer oil in the jacket 802 can be recovered and temporarily stored for insulation to ensure the heating effect while avoiding heat waste; the subsequently added materials can be preheated and fed at different heights to avoid the materials from adhering to the stirring blades 807, while improving the efficiency and effect of stirring. Moreover, by preheating, the reaction temperature can be quickly reached, shortening the overall reaction time, thereby improving the efficiency and effect of the reaction.

[0048] The lifting mechanism includes a guide rail 201 fixedly connected to the top of the bottom plate 1, and a push plate 202 is slidably connected to the guide rail 201, and the side wall of the push plate 202 is provided with a first inclined surface 203 and a second inclined surface 205, and the top of the movable ring 11 is fixedly connected with an L-shaped push rod 204, and the side wall of the insulation box 808 is fixedly connected to two symmetrically arranged connecting blocks 207, and the top of each connecting block 207 is inserted with a T-shaped guide rod 206, the lower end of the T-shaped guide rod 206 is fixed to the top of the bottom plate 1, and the side wall of each T-shaped guide rod 206 is provided with a first spring 208. During the reaction, polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin, and antioxidant are put into the kettle body 801 through the first feed valve 803. Then, according to the liquid level of the material, the movable ring 11 is driven to move downward and adjusted through the lifting module 10 to ensure that it is consistent with the height of the material. At the same time, when the movable ring 11 moves downward When the end of the pushing rod 204 slides along the first inclined surface 203 to the side wall of the pushing plate 202, the pushing plate 202 can be pushed along the guide rail 201 to move in the direction close to the connecting block 207, and the second inclined surface 205 is abutted against the side wall of the connecting block 207, thereby pushing the insulation box 808 to move upward. At the same time, the first spring 208 is compressed. At this time, the heat transfer oil temporarily stored in the insulation box 808 can be filled into the jacket 802 through the return oil pipe 812 and the oil extraction pipe 813. When the kettle body 801 is no longer needed to be heated, the moving ring 11 is driven upward and reset by the lifting module 10. At this time, the insulation box 808 can be moved downward and reset under the action of the first spring 208, so that the heat transfer oil in the jacket 802 can return to the insulation box 808 through the return oil pipe 812 and the oil extraction pipe 813 for temporary insulation, avoiding heat waste and being more energy-saving and environmentally friendly.

[0049] The preheating mechanism includes a preheating box 301 fixedly connected to the lower end of the second feed valve 814, and a hollow cover 302 is fixedly provided on the side wall of the preheating box 301, an annular tube 304 is fixedly connected to the side wall of the hollow cover 302, and a first connecting tube 303 is fixedly connected between the annular tube 304 and the oil supply pipe 810, a second connecting tube 305 is fixedly connected between the hollow cover 302 and the insulation box 808, and a solenoid valve 313 is fixedly connected to the bottom of the preheating box 301, and The other end of the solenoid valve 313 is fixedly connected to the feeding pipe 312, the stirring rod 806 is provided with a cylindrical cavity 314, and the side wall of the cylindrical cavity 314 is fixedly inserted with a fixed pipe 309, the other end of the fixed pipe 309 is fixedly connected to the annular cover 310, and the annular cover 310 is rotatably connected to the rotating ring 311, the feeding pipe 312 is fixedly inserted into the side wall of the rotating ring 311, and the side wall of the cylindrical cavity 314 is provided with a plurality of feeding holes 315, and the feeding holes 315 are fixedly inserted into the side wall of the rotating ring 311. A one-way valve is provided, and the conducting direction of the one-way valve is from the cylindrical cavity 314 to the outside. An extrusion mechanism is provided in the cylindrical cavity 314. A fixed box 306 is fixedly connected to the top of the preheating box 301, and a circular hole 307 is opened on the side wall of the fixed box 306. A filter 308 is fixedly connected in the circular hole 307. A stirring mechanism is provided in the preheating box 301, and a scraping mechanism is provided on the side wall of the filter 308. In steps S2 and S3, when it is necessary to add the isocyanate IPDI or isocyanate MDI-100 material, the second feed valve 814 is first opened to allow the material to enter the preheating box 301 through the second feed valve 814. At this time, the heated heat transfer oil can enter the first connecting pipe 303 through the oil supply pipe 810, and enter the hollow cover 302 through the annular pipe 304. Then, it returns to the insulation box 808 through the second connecting pipe 305. At this time, the material in the preheating box 301 can be preheated.

[0050] The stirring mechanism includes a rotating rod 401 rotatably connected to the preheating box 301, and a plurality of stirring plates 402 arranged in an array are fixedly connected to the side wall of the rotating rod 401. The end of the rotating rod 401 near the outlet of the annular tube 304 is fixedly connected to a turbine 403. When the heat transfer oil enters the hollow cover 302, it can impact the turbine 403, thereby driving the turbine 403 to rotate. The rotation of the turbine 403 drives the rotating rod 401 and the stirring plate 402 to rotate, which can automatically stir the material in the preheating box 301 and ensure the efficiency and effect of heating.

[0051] The scraping mechanism includes a rotating shaft 501 rotatably connected to the fixed box 306, and the side wall of the rotating shaft 501 is fixedly connected to a plurality of scrapers 502 arranged in an array, one end of the rotating shaft 501 is fixedly connected to a driven pulley 503, and the side wall fixed sleeve of the rotating rod 401 is provided with a driving pulley 504, and the driving pulley 504 and the driven pulley 503 are transmitted by a belt 505. Isocyanate MDI-100 is a solid and may generate dust during preheating and stirring. The filter 308 can prevent the dust from being sucked away during vacuuming, resulting in material waste, and when the driven pulley 503 rotates, the scraper 502 can be driven to rotate through the rotating shaft 501. At this time, the powder adhered to the surface of the filter 308 can be scraped and cleaned, avoiding material waste while ensuring the vacuuming effect.

[0052] The extrusion mechanism includes an L-shaped plate 601 fixedly connected to the top of the kettle body 801, and the top of the L-shaped plate 601 is fixedly connected to a cylinder 602, and the cylinder 602 includes a piston rod 603, and the lower end of the piston rod 603 passes through the cylindrical cavity 314 and is fixedly connected to a piston 604. When heated to the reaction temperature, the solenoid valve 313 is opened, and the material can enter the annular cover 310 through the feeding pipe 312, and then enter the cylindrical cavity 314 through the fixed pipe 309. Then, the cylinder 602 is started, and the piston 604 is driven by the piston rod 603 to move downward along 314, so that the material in the cylindrical cavity 314 can be squeezed and enter the kettle body 801 through the feeding hole 315 for reaction. Feeding at different heights can prevent the material from adhering to the stirring blade 807, while improving the efficiency and effect of stirring.

[0053] The driving mechanism includes a ring gear 701 fixedly mounted on the side wall of the stirring rod 806, and a U-shaped plate 702 is fixedly connected to the top of the kettle body 801, and a motor 703 is fixedly connected to the top of the U-shaped plate 702. The output end of the motor 703 is fixedly connected to a gear 704, and the gear 704 is meshed with the ring gear 701. When the motor 703 is started, the rotation of the motor 703 drives the rotation of the gear 704, thereby driving the ring gear 701 and the stirring rod 806 to rotate, and then driving the stirring blade 807 to stir.

[0054] Examples 1-7, specific preparation raw materials are shown in Table 1:

[0055] Table 1: Raw material dosage of Examples 1-7 (kg)

[0056]

[0057] Performance determination of polyurethane hot melt adhesive:

[0058] Determination of viscosity: The viscosity was tested using an NDJ-1C hot melt adhesive viscometer with a rotor of 29, a speed of 10 rpm, a temperature of 130°C, and a time detection setting of 10 min.

[0059] Determination of open time: melt the product at 130℃ for 60min, then apply it on A4 paper with a 90μm film-making device, and laminate it with kraft paper with a width of 1cm and a length of 5cm. The end point is when the kraft paper does not stick.

[0060] Determination of initial adhesion: melt the product at 130℃ for 120min, then use a 120μm film-making device to apply it to the TPR substrate, quickly laminate the prepared EVA, and then roller press it. Then use a cutter to cut the laminated EVA substrate into 1cm wide strips. After 5min, quickly use a tensile testing machine with a clamp to pull it up at a constant speed and read the value when it is constant.

[0061] Determination of yellowing resistance: melt the product at 130℃ for 120min, then use a 120μm film-making device to scrape and apply it on 8cm*8cm tiles. Curing at 25℃ for 72 hours, then place it in a Type B yellowing irradiator for 3 hours. The yellowing grades are divided into poor, general and excellent according to the colorimetric method used in actual production applications.

[0062] Determination of final bonding strength: The product was melted at 130°C for 120 minutes, then coated on a TPR substrate using a 120-micron film former. The prepared EVA was quickly laminated, followed by roller lamination. The laminated EVA substrate was then cut into 1-cm wide strips using a cutter. The strips were cured at 25°C for 72 hours, then pulled up at a constant speed using a tensile testing machine with a fixture. The readings were taken when the values ​​remained constant. The test results are shown in Table 2:

[0063] Table 2: Application test results of Examples 1-7

[0064]

[0065] Comparing Example 1 with Examples 2-5, it can be seen that the introduction of IPDI into S1 using the polyurethane hot melt adhesive preparation method can improve initial tack strength, significantly improve yellowing resistance, increase initial tack, and achieve excellent final strength. It can also be seen from Example 5 that the addition of only isocyanate IPDI into S1 results in relatively poor final adhesion. Comparing Example 3, it can be seen from Example 6 that replacing the liquid polyester with a highly crystalline polyester polyol significantly shortens the open time and significantly increases initial tack. Comparing Example 3, it can be seen from Example 7 that the presence of EVA resin can better enhance adhesion to the EVA substrate.

[0066] Therefore, during the preparation of the polyurethane hot melt adhesive, the yellowing resistance of the adhesive was enhanced by selecting a variety of isocyanates. A two-step isocyanate dosage design effectively enhanced its initial tack. Furthermore, a carefully selected combination of different types of polyester polyols, tackifying resins, and thermoplastic resins significantly improved initial tack strength and adhesion to the substrate.

[0067] Furthermore, in the prepolymerization step, 0.8% silane coupling agent KH550 modified nano-CeO2 with a particle size of 30 nm can be added during dehydration, and the high temperature of 135°C in the dehydration stage can be used to achieve an ester exchange reaction between the hydroxyl groups on the surface of the nanoparticles and the polyol; to further improve the yellowing resistance, 1.5% microencapsulated tackifier core material: hydrogenated rosin ester, wall material: PU prepolymer can be added after 1 hour of polymerization reaction. The microcapsules rupture during subsequent hot pressing processing to release the tackifying components, further improving the initial viscosity.

[0068] Working principle: During the reaction, polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin and antioxidant are put into the kettle body 801 through the first feed valve 803. Then, according to the liquid level of the material, the moving ring 11 is driven to move downward and adjusted by the lifting module 10 to ensure that it is consistent with the height of the material. At the same time, when the moving ring 11 moves downward, it can drive the push rod 204 to move downward synchronously. When the end of the push rod 204 slides along the first inclined surface 203 to the side wall of the push plate 202, it can push the push plate 202 to move along the guide rail 201 toward the direction close to the connecting block 207, and make the second inclined surface 205 abut against the side wall of the connecting block 207, thereby pushing the insulation box 808 to move upward. At the same time, the first spring 208 is compressed. At this time, the heat transfer oil temporarily stored in the insulation box 808 can be filled into the jacket 802 through the return oil pipe 812 and the oil extraction pipe 813.

[0069] Next, the circulation pump 809 is started, so that the heat transfer oil in the heat preservation box 808 enters the electric heater 811 through the oil extraction pipe 813 for heating, and then enters the jacket 802 through the oil supply pipe 810 after heating, and then returns to the heat preservation box 808 again through the return oil pipe 812, so that the heat transfer oil in the jacket 802 can be circulated, and the material is heated to 135-140℃. The material is vacuum dehydrated for 2 hours under the stirring condition of 250r / min, so that the height of the heat transfer oil in the jacket 802 can be adjusted according to the height of the material. The kettle body 801 is not required to be heated, and the movable ring 11 is driven upward and reset by the lifting module 10. At this time, the heat preservation box 808 can be moved downward and reset under the action of the first spring 208, so that the heat transfer oil in the jacket 802 can be returned to the heat preservation box 808 through the return oil pipe 812 and the oil extraction pipe 813 for temporary insulation storage, thereby avoiding heat waste and being more energy-saving and environmentally friendly.

[0070] At the same time, in step S2 and step S3, when the material isocyanate IPDI or isocyanate MDI-100 needs to be added, the second feed valve 814 is first opened to allow the material to enter the preheating box 301 through the second feed valve 814. At this time, the heated heat transfer oil can enter the first connecting pipe 303 through the oil supply pipe 810, and enter the hollow cover 302 through the annular pipe 304, and then return to the insulation box 808 through the second connecting pipe 305. At this time, the material in the preheating box 301 can be preheated. When the heat transfer oil enters the hollow cover 302, it can impact the turbine 403, thereby driving the turbine 403 to rotate. The rotation of the turbine 403 drives the rotating rod 401 and the stirring plate 402 to rotate, which can automatically stir the material in the preheating box 301 to ensure the efficiency and effect of heating.

[0071] Moreover, when the rotating rod 401 rotates, it can drive the driving pulley 504 to rotate, and at the same time, the driven pulley 503 is driven to rotate through the belt 505. When the driven pulley 503 rotates, it can drive the scraper 502 to rotate through the rotating shaft 501. At this time, the powder adhering to the surface of the filter 308 can be scraped and cleaned, avoiding material waste while ensuring the vacuum effect. The material is heated to the reaction temperature. When the reaction is required, the solenoid valve 313 is opened, and the material can enter the annular cover 310 through the feeding pipe 312. Then, it enters the cylindrical cavity 314 through the fixed tube 309, and then, the cylinder 602 is started, and the piston 604 is driven to move downward along 314 through the piston rod 603, so that the material in the cylindrical cavity 314 can be squeezed and enter the kettle body 801 through the feeding hole 315 for reaction. Feeding at different heights can prevent the material from adhering to the stirring blade 807, while improving the efficiency and effect of stirring. Moreover, by preheating, the reaction temperature can be quickly reached, shortening the overall reaction time, thereby improving the efficiency and effect of the reaction.

[0072] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology. It will not be described in detail here. The content not described in detail in this specification belongs to the existing technology known to professional and technical personnel in this field.

[0073] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A polyurethane hot melt adhesive for shoes, characterized by: The invention comprises the following components in parts by weight: 50-70 parts of polyester polyol, 2-10 parts of dimer acid modified polyol, 5-15 parts of tackifying resin, 5-10 parts of thermoplastic resin, 0.1-0.5 parts of antioxidant, 0-19 parts of isocyanate, 0.2-0.5 parts of coupling agent and 0.1-0.5 parts of catalyst.

2. The polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The polyester polyol model is any one or more of Evonik 7250, Evonik 7360, Evonik 7361, Evonik 7380, Evonik 7150, and Asahikawa Chemical XCP-PA110N; the dimer acid-modified polyol is any one or more of DA-21, DA-2026, and DA-3190 of Shanghai Jingri Chemical; and the thermoplastic resin is any one or more of acrylic resin, saturated polyester resin, TPU resin, EVA resin, or polyolefin resin.

3. The polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The antioxidant is any one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite; the isocyanate is any one or more of diisocyanate diphenylmethane diisocyanate, isophorone diisocyanate, and carbodiimide-modified diphenylmethyl diisocyanate; the coupling agent is any one or more of silane coupling agents γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane; and the catalyst is any one or more of dibutyltin dilaurate, stannous octoate, triethyleneamine, and dimorpholine diethyl ether.

4. A process for manufacturing the polyurethane hot melt adhesive for shoes according to any one of claims 1 to 3, characterized in that: The steps include: S1: Weigh the corresponding fractional weights of raw materials, add polyester polyol, dimer acid modified polyol, tackifying resin, thermoplastic resin, and antioxidant into a reaction apparatus, heat to 135-140°C, and vacuum dehydrate at 250 rpm for 2 hours; S2: Cool the mixture to 120°C, add isocyanate IPDI to the reaction apparatus, and react at 130-135°C for 1.5 h at a stirring speed of 350 r / min under vacuum conditions; S3: Cool to 120°C, continue to add isocyanate MDI-100 to the reaction apparatus, heat to 135°C, add coupling agent and catalyst, and react at a stirring speed of 350 r / min under vacuum conditions for 1.5 hours; S4: After stirring for 0.5 h under vacuum conditions, the material is discharged and then placed into an aluminum foil bag. The air is replaced with nitrogen and then sealed for storage; The reaction device comprises a bottom plate (1) and a reactor body, wherein the reactor body comprises a reactor body (801) and a hollow jacket (802), and a discharge valve (805) is provided at the bottom of the reactor body (801), a first feed valve (803) and a second feed valve (814) are provided at the top of the reactor body (801), and a vacuum pump (804) is provided at the top of the reactor body (801), and the top of the reactor body (801) is rotatably connected to a plurality of stirring blades (807) via a stirring rod (806), the top of the bottom plate (1) is connected to an insulation box (808) via a lifting mechanism, and a circulation pump (809) is fixedly connected to the top of the bottom plate (1), and the circulation pump (809) and the jacket (802) are connected. An oil supply pipe (810) is fixedly connected between the jacket (802) and the insulation box (808), and an oil return pipe (812) is fixedly connected between the jacket (802) and the insulation box (808). An oil extraction pipe (813) is fixedly connected between the circulation pump (809) and the insulation box (808), and an electric heater (811) is provided on the side wall of the oil supply pipe (810). An annular groove (9) is provided on the top of the jacket (802), and a movable ring (11) is connected to the annular groove (9) through a lifting module (10). A vent valve (12) is fixedly inserted on the top of the movable ring (11). A preheating mechanism for preheating the added material is provided at the lower end of the second feed valve (814), and the rotation of the stirring rod (806) is driven by a driving mechanism.

5. The manufacturing process of a polyurethane hot melt adhesive for shoes according to claim 4, characterized in that: The lifting mechanism comprises a guide rail (201) fixedly connected to the top of the base plate (1), and a push plate (202) is slidably connected to the guide rail (201), the side wall of the push plate (202) is provided with a first inclined surface (203) and a second inclined surface (205), and the top of the movable ring (11) is fixedly connected with an L-shaped push rod (204), the side wall of the thermal insulation box (808) is fixedly connected with two symmetrically arranged connecting blocks (207), and the top of each connecting block (207) is inserted with a T-shaped guide rod (206), the lower end of the T-shaped guide rod (206) is fixed to the top of the base plate (1), and the side wall of each T-shaped guide rod (206) is sleeved with a first spring (208).

6. The manufacturing process of a polyurethane hot melt adhesive for shoes according to claim 4, characterized in that: The preheating mechanism comprises a preheating box (301) fixedly connected to the lower end of the second feed valve (814), and a hollow cover (302) is fixedly sleeved on the side wall of the preheating box (301), an annular tube (304) is fixedly connected to the side wall of the hollow cover (302), and a first connecting tube (303) is fixedly connected between the annular tube (304) and the oil supply pipe (810), a second connecting tube (305) is fixedly connected between the hollow cover (302) and the insulation box (808), a solenoid valve (313) is fixedly connected to the bottom of the preheating box (301), and the other end of the solenoid valve (313) is fixedly connected to the feed pipe (312), a cylindrical cavity (314) is opened in the stirring rod (806), and a fixed tube (314) is fixedly inserted into the side wall of the cylindrical cavity (314) (309), the other end of the fixed tube (309) is fixedly connected to an annular cover (310), and a rotating ring (311) is rotatably connected inside the annular cover (310), the feeding tube (312) is fixedly inserted into the side wall of the rotating ring (311), and a plurality of feeding holes (315) are provided on the side wall of the cylindrical cavity (314), a one-way valve is provided in the feeding hole (315), and an extrusion mechanism is provided in the cylindrical cavity (314), the top of the preheating box (301) is fixedly connected to a fixed box (306), and a circular hole (307) is provided on the side wall of the fixed box (306), a filter (308) is fixedly connected inside the circular hole (307), a stirring mechanism is provided in the preheating box (301), and a scraping mechanism is provided on the side wall of the filter (308).

7. The manufacturing process of a polyurethane hot melt adhesive for shoes according to claim 6, characterized in that: The stirring mechanism comprises a rotating rod (401) rotatably connected to the preheating box (301), and a plurality of stirring plates (402) arranged in an array are fixedly connected to the side wall of the rotating rod (401), and a turbine (403) is fixedly connected to the end of the rotating rod (401) close to the outlet of the annular tube (304).

8. The manufacturing process of a polyurethane hot melt adhesive for shoes according to claim 6, characterized in that: The scraping mechanism comprises a rotating shaft (501) rotatably connected to a fixed box (306), and a plurality of scrapers (502) arranged in an array are fixedly connected to the side wall of the rotating shaft (501), one end of the rotating shaft (501) is fixedly connected to a driven pulley (503), and a driving pulley (504) is fixedly provided on the side wall of the rotating rod (401), and transmission is performed between the driving pulley (504) and the driven pulley (503) via a belt (505).

9. The manufacturing process of a polyurethane hot melt adhesive for shoes according to claim 6, characterized in that: The extrusion mechanism includes an L-shaped plate (601) fixedly connected to the top of the kettle body (801), and the top of the L-shaped plate (601) is fixedly connected to a cylinder (602). The cylinder (602) includes a piston rod (603), and the lower end of the piston rod (603) passes through the cylindrical cavity (314) and is fixedly connected to a piston (604).

10. The manufacturing process of polyurethane hot melt adhesive for shoes according to claim 4, characterized in that: The driving mechanism comprises a gear ring (701) fixedly sleeved on the side wall of the stirring rod (806), and a U-shaped plate (702) is fixedly connected to the top of the kettle body (801), a motor (703) is fixedly connected to the top of the U-shaped plate (702), and a gear (704) is fixedly connected to the output end of the motor (703), and the gear (704) is meshed with the gear ring (701).

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