Novel water-based hot melt adhesive mixing method, novel water-based hot melt adhesive, composite leather production method based on the novel water-based hot melt adhesive, and composite leather

Abstract

The present disclosure provides a mixing method of a novel water-based hot melt adhesive, a novel water-based hot melt adhesive, a composite leather production method based on the novel water-based hot melt adhesive, and composite leather. In the above-mentioned mixing method, a modified emulsifier and deionized water are placed in an airflow mixing tank of a mixing device for mixing to obtain an emulsified water liquid; polyurethane resin, EVA resin emulsion and water-based acrylic resin are placed in a premixing tank of a mixing device for high-temperature heating and mixing, and then the emulsified water liquid and the resin melt are simultaneously sent to a stirring tank of the mixing device, and the emulsified water liquid and the resin melt are controlled to intersect and mix during the spraying process; then the emulsified water liquid and the resin melt are alternately mixed at low and medium speeds under vacuum conditions to obtain a resin emulsion; a thermosensitive delayed amine catalyst is added to the resin emulsion for mixing at room temperature to obtain a novel water-based hot melt adhesive. This method can prepare a novel water-based hot melt adhesive with low permeability, good softness, good adhesion, and conducive to spraying.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based hot melt adhesive processing, and in particular to a novel mixing method of water-based hot melt adhesive, a novel water-based hot melt adhesive, a composite leather manufacturing method based on the novel water-based hot melt adhesive, and the composite leather. Background Art

[0002] Composite leather is one of the main raw materials for bags. In the production process of composite leather, a large amount of glue is usually used to bond and fix different leather base materials. The glue used in the early days was mostly yellow glue, white glue, powder glue and water-based PU glue. This type of glue contains formaldehyde solvent, which not only has a strong odor when used, but also has great harm to the human body.

[0003] For this reason, a new type of water-based hot melt adhesive has appeared on the market, such as the new water-based hot melt adhesive disclosed in Chinese document No. CN114032048 A, which is specifically disclosed to be composed of 30-35% EVA resin, 20-25% water-based acrylic resin, 8-10% melamine resin, 30-35% deionized water, and 3-5% emulsifier. Deionized water is used to directly replace the formaldehyde solvent, which is not only environmentally friendly but also has a good bonding effect, and effectively solves the problem of early glue being environmentally unfriendly.

[0004] In practical applications, the mixing and emulsification process plays a particularly important role in the preparation of water-based environmentally friendly hot melt adhesives, which directly determines the stability of the water-based environmentally friendly hot melt adhesive system. For this reason, a special mixing and stirring device for water-based environmentally friendly hot melt adhesives has appeared on the market, such as the new water-based hot melt adhesive raw material stirring device mentioned in Chinese patent document No. CN213078252U, to effectively ensure the stability of the water-based environmentally friendly hot melt adhesive system.

[0005] However, the current new water-based hot melt adhesive raw material stirring device generally adopts manual pouring or automatic pumping when adding liquid materials, such as deionized water, emulsion, etc., and both methods have the problem of concentrated liquid material entering, resulting in the inability to quickly and evenly mix various raw materials, and there are problems such as high mixing and stirring speed and high stirring energy consumption.

[0006] In addition, due to the high mixing and stirring energy, the new water-based hot melt adhesive is prone to over-emulsification and other phenomena, which affects the bonding performance of the water-based environmentally friendly hot melt adhesive; and the traditional water-based environmentally friendly hot melt adhesive has a fast curing speed, which is not conducive to the flow of subsequent spray glue, which can easily cause the water-based hot melt adhesive to be easily cured during the spraying process, affecting the quality of the spray glue. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a mixing method for a new water-based hot melt adhesive with low permeability, good softness, good adhesion and conducive to spraying, a new water-based hot melt adhesive, a composite leather production method based on the new water-based hot melt adhesive and composite leather.

[0008] The purpose of this disclosure is achieved through the following technical solutions:

[0009] A novel mixing method of water-based hot melt adhesive, which mixes and emulsifies a variety of materials through a mixing device, comprises the following steps:

[0010] Prepare various materials according to the formula of the novel water-based hot melt adhesive;

[0011] Putting the modified emulsifier and deionized water into the air flow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution; and,

[0012] Putting polyurethane resin, EVA resin emulsion and water-based acrylic resin into the premixing tank of the mixing device for high-temperature heating and mixing to obtain a resin melt;

[0013] The emulsified water liquid and the resin melt are simultaneously fed into the stirring tank of the mixing device, and the emulsified water liquid and the resin melt are controlled to intersect and mix during the spraying process;

[0014] Wherein, the mixing device comprises a stirring tank, a first feeding pipe and a second feeding pipe; the first feeding pipe is used to convey the emulsified aqueous solution; the second feeding pipe is used to convey the resin melt, the first feeding pipe and the second feeding pipe are located above the stirring tank and are respectively connected to the stirring tank; the spraying direction of the first feeding pipe and the discharge direction of the second feeding pipe form a preset angle;

[0015] A spoiler is provided in the first feed pipe, the spoiler is connected to the first feed pipe, and a plurality of conical nozzles are formed on a side of the spoiler away from the first feed pipe, so that the emulsified water can be dispersed by the spoiler when spraying;

[0016] Under vacuum conditions, the emulsified aqueous solution and the resin melt are alternately mixed at low and medium speeds to obtain a resin emulsion;

[0017] The thermosensitive delayed amine catalyst is added into the resin emulsion and mixed at room temperature to obtain the novel water-based hot melt adhesive.

[0018] In one embodiment, the total injection projection area of ​​the spoiler is located in the discharge direction of the second feed pipe.

[0019] In one of the embodiments, when the emulsified aqueous liquid and the resin melt are controlled to intersect and mix during the spraying process, the starting point of the intersect and mix is ​​set adjacent to the discharge port of the second feed pipe.

[0020] In one embodiment, the first feed pipe is obliquely arranged on the stirring tank, and the second feed pipe is vertically arranged on the stirring tank.

[0021] In one of the embodiments, the spraying direction of each of the conical nozzles is inclined downward.

[0022] In one of the embodiments, the plurality of conical nozzles spray liquid alternately.

[0023] In one embodiment, the thermosensitive delayed amine catalyst is a polyphenol thermosensitive delayed catalyst; and / or,

[0024] The modified emulsifier includes at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate and linear polyglycerol ester.

[0025] A novel water-based hot melt adhesive is prepared by the mixing method of the novel water-based hot melt adhesive described in any of the above embodiments.

[0026] A method for producing composite leather comprises the following steps:

[0027] Obtaining a leather base material; wherein the leather base material comprises a surface and a rubber-coated surface;

[0028] The leather base material is delivered to the bottom of the glue spraying component of the automatic glue spraying equipment through the conveying component of the automatic glue spraying equipment;

[0029] The glue spraying component applies the novel water-based hot melt adhesive of any of the above embodiments onto the glue-coated surface of the leather base material to obtain a glue-leather layer;

[0030] The glue-leather layer is naturally ventilated and air-dried for later use;

[0031] Laminating the fabric to be pressed with the glue-leather layer to obtain leather A to be pressed;

[0032] The leather A to be pressed is subjected to heating and pressing operation to obtain the composite leather.

[0033] A composite leather is obtained by using the composite leather production method described in any one of the above embodiments.

[0034] Compared with the prior art, the present invention has at least the following advantages:

[0035] 1) The modified emulsifier and deionized water are placed in the air flow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution, so as to ensure that the hydrophilic end of the modified emulsifier can be well dispersed on the water interface, so that the emulsified aqueous solution can subsequently quickly enter the resin melt to achieve a more uniform dispersion; at the same time, the polyurethane resin, EVA resin emulsion and water-based acrylic resin are placed in the premixing tank of the mixing device for high-temperature heating and mixing to obtain a resin melt; the emulsified aqueous solution and the resin melt are prepared separately; and because the mixing device includes a stirring tank, a first feeding pipe and a second feeding pipe; the first feeding pipe is used to transport the emulsified aqueous solution; the second feeding pipe is used to transport the resin melt, the first feeding pipe and the second feeding pipe are located above the stirring tank and are respectively connected to the stirring tank; so that the mixing device can simultaneously feed the emulsified aqueous solution and the resin melt into the stirring tank, and because the spraying direction of the first feeding pipe and the discharge direction of the second feeding pipe form a preset angle, and the disturbance A plurality of conical nozzles are formed on one side of the flow member away from the first feed pipe, so that the emulsified water liquid can be dispersed by the spoiler when spraying, so that the dispersed emulsified water liquid can be fully mixed with the resin melt, and the emulsified water liquid and the resin melt can intersect and mix during the spraying process, so that the resin melt can use its own waste heat temperature to achieve preliminary mixing and emulsification with the emulsified water liquid, which not only improves the utilization rate of the waste heat of the resin melt, but also ensures the preliminary mixing and emulsification effect of the resin melt and the emulsified water liquid, and effectively reduces the subsequent stirring speed and stirring time, that is, the subsequent emulsified water liquid and the resin melt only need to be mixed alternately at low and medium speeds to achieve sufficient mixing and stirring, without the need for high-speed mixing. In this way, the new water-based hot melt adhesive can be effectively prevented from being over-emulsified or the particle size being sheared very small during the mixing and stirring process, and the new water-based hot melt adhesive can be effectively ensured to have good bonding performance and low permeability; thereby effectively avoiding the problem of the new water-based hot melt adhesive containing too many small molecular materials penetrating into the leather base material and causing the composite leather to harden.

[0036] 2) Since the addition of the thermal-sensitive delayed amine catalyst can effectively inhibit the curing speed of the new water-based hot melt adhesive during the spraying process, it ensures that the new water-based hot melt adhesive can maintain good fluidity during the spraying process, which is beneficial to the subsequent spraying process, thereby ensuring that a thin, uniform, low-permeability, good adhesion and good softness of the new water-based environmentally friendly hot melt adhesive layer is obtained on the glue-coated surface of the leather base material. In addition, the added thermal-sensitive delayed amine catalyst prolongs the curing time, so that the composite leather manufacturer can make advance production preparations for large orders to better meet the production delivery period of large orders in the e-commerce market. Since the thermal-sensitive delayed amine catalyst is added to the resin emulsion for mixing at room temperature, it is ensured that the thermal-sensitive delayed amine catalyst will not catalyze due to high temperature during the mixing and stirring process, so as to ensure that the added thermal-sensitive delayed amine catalyst will play a stronger catalytic role in the subsequent heating and pressing operation, so as to achieve rapid bonding between the fabric to be pressed and the leather base material, and at the same time, it also avoids the phenomenon that the stirring parts are easily adhered due to the catalytic effect of the thermal-sensitive delayed amine catalyst in the mixing process.

[0037] 3) Compared with the traditional general emulsifier, the modified emulsifier disclosed in the present invention includes at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester, and has a larger molecular weight than the traditional general emulsifier, so as to increase the molecular weight of the modified emulsifier itself, and effectively avoid the problem that the traditional water-based hot melt adhesive has more small molecular materials, resulting in its high permeability and affecting the flexibility of the composite leather; and ensure that the various components of the modified emulsifier can play a good synergistic role, so that the emulsified water can quickly enter the resin melt, so as to better ensure the emulsification effect of the new water-based hot melt adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 It is a flow chart of a mixing method of a novel water-based hot melt adhesive according to an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the structure of a mixing device in one direction according to an embodiment of the present invention;

[0041] Figure 3 A cross-sectional view of a mixing device in one direction according to another embodiment of the present invention;

[0042] Figure 4 for Figure 3The enlarged view of point A shown in FIG.

[0043] Figure 5 A cross-sectional view of a first premixing assembly in one direction according to an embodiment of the present invention;

[0044] Figure 6 for Figure 5 The enlarged view of point B shown in FIG.

[0045] Figure 7 It is a comparison diagram of the products after peeling of Example 1 of the present invention and Comparative Example 1.

[0046] Figure numerals: 10, mixing device; 100, first premixing assembly; 110, airflow mixing tank; 120, third feed pipe; 130, first aeration sub-disc; 131, first aeration head; 140, second aeration sub-disc; 200, second premixing assembly; 210, premixing tank; 220, fourth feed pipe; 230, first drive; 240, first stirring element; 300, stirring assembly; 310, stirring tank; 320, second drive; 330, second stirring element; 340, first feed pipe; 350, second feed pipe; 360, fifth feed pipe; 400, spoiler; 410, conical nozzle. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0048] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0050] See also Figure 1In order to better understand the technical solution and beneficial effects of the present disclosure, the present disclosure is further described in detail below in conjunction with specific embodiments. A novel water-based hot melt adhesive mixing method of one embodiment, wherein a plurality of materials are mixed and emulsified by a mixing device, comprises part or all of the following steps:

[0051] S101, prepare various materials according to the formula of the novel water-based hot melt adhesive. Specifically, prepare various materials according to the formula of the novel water-based hot melt adhesive to prepare the ingredients of the novel water-based hot melt adhesive.

[0052] In one embodiment, the novel water-based hot melt adhesive includes 35 to 50 parts of EVA resin emulsion, 30 to 40 parts of water-based acrylic resin; 40 to 50 parts of polyurethane resin; 1 to 3 parts of thermal delayed amine catalyst, 3.5 to 7 parts of modified emulsifier, and 20 to 25 parts of deionized water.

[0053] It can be understood that according to the formula of the new water-based hot melt adhesive, the amounts of EVA resin emulsion, water-based acrylic resin, polyurethane resin, thermal delayed amine catalyst and deionized water are weighed to prepare for mixing.

[0054] It should be noted that in actual applications, due to the fast curing speed of traditional water-based hot melt adhesive, it is easy to solidify during the subsequent glue spraying process, which is not conducive to the flow of water-based environmentally friendly hot melt adhesive on the leather surface, especially for some composite leathers with less glue coating, this solidification phenomenon is more obvious, and the nozzle is prone to clogging. Therefore, by adding 1 to 3 parts of thermal delay amine catalyst, the added 1 to 3 parts of thermal delay amine catalyst can effectively delay the curing time of the new water-based hot melt adhesive to ensure that the glue spraying nozzle is not prone to clogging, and it is conducive to preparing a thin, uniform, low-permeability, good adhesion and good softness new water-based hot melt adhesive layer on the glue coating surface of the leather base material.

[0055] S102, placing the modified emulsifier and deionized water into the air flow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution, so as to prepare a uniform emulsified aqueous solution.

[0056] In one embodiment, the modified emulsifier includes at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate and linear polyglycerol ester.

[0057] It can be understood that, as the new water-based hot melt adhesive of Chinese document number CN 114032048 A mentioned in the background technology, the emulsifier used is an anionic surfactant, pentaerythritol triacrylate and an auxiliary emulsifier according to a mass ratio of 1:1:0.5, and the specific anionic surfactant includes sodium dodecylbenzene sulfonate, fatty acid methyl ester ethoxylate sulfonate or sodium dodecyl sulfate; and the auxiliary emulsifier is ethylene glycol, propylene glycol or linear polyglycerol ester. It can be seen that the molecular weight of traditional emulsifiers is usually relatively small, which is conducive to the rapid mixing and dispersion of small molecule emulsifiers. However, in actual applications, due to the influence of traditional stirring parts, such small molecule emulsifiers will be sheared very small, and because the use of emulsifiers is usually relatively small, it is easy to cause the problem of over-emulsification of small molecule emulsifiers, thereby causing more small molecule materials in traditional water-based hot melt adhesives. In this way, when the water-based hot melt adhesive is applied to the leather base material, more small molecule materials are easy to penetrate into the leather base material to cause the problem of hardening of the composite leather.

[0058] Therefore, in order to solve the problem of composite leather becoming hard due to glue coating, in the present disclosure, the traditional emulsifier is modified, that is, at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester are used. Since the molecular weight of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester is relatively large, the molecular weight of the modified emulsifier itself is increased, which effectively reduces the problem of composite leather becoming hard due to the infiltration of more small molecular materials in the traditional water-based hot melt adhesive into the leather base material.

[0059] In one embodiment, the average degree of polymerization n of octylphenol polyoxyethylene ether is in the range of 7

[0060] In one embodiment, the average degree of polymerization N in the linear polyglycerol ester is in the range of 2

[0061] In a preferred embodiment, the mass ratio of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester is 0.5:1:0.5:1.5, so that octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester can play a good synergistic effect. On the premise of meeting a higher level of mixed emulsification and dispersion, it is also ensured that the new water-based hot melt adhesive finally prepared has lower permeability, wettability and fluidity, and effectively avoids the problem that the traditional water-based hot melt adhesive contains more small molecular materials, resulting in its higher permeability and affecting the flexibility of the composite leather, so as to ensure that a thin and uniform water-based environmentally friendly hot melt adhesive layer is coated.

[0062] In one embodiment, the step of placing the modified emulsifier and deionized water into the airflow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution includes the following specific steps: first, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester are weighed according to a mass ratio of 0.5:1:0.5:1.5, and then deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester are sequentially added into the airflow mixing tank for airflow mixing to obtain an emulsified aqueous solution.

[0063] It can be understood that by mixing deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol esters with air flow, multiple air flows can achieve sufficient mixing of deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol esters, effectively avoiding the problem of traditional built-in stirring parts causing large shear force on octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol esters, resulting in higher permeability of the prepared new water-based hot melt adhesive and causing hardening of the composite leather.

[0064] like Figure 5 and Figure 6 As shown, in one embodiment, the mixing device 10 includes a first premixing assembly 100, a second premixing assembly 200 and a stirring assembly 300. The airflow mixing tank 110 of the first premixing assembly 100 and the mixing tank of the second premixing assembly 200 are respectively connected to the stirring tank 310 of the stirring assembly 300. The first premixing assembly 100 includes the airflow mixing tank 110, a third feed pipe 120 and an aeration plate, the third feed pipe 120 is connected to the airflow mixing tank 110, and the aeration plate is connected and arranged in the airflow mixing tank 110. When the aeration plate is connected to the external air supply assembly, the airflow will enter the airflow mixing tank 110 from the aeration plate to form multiple airflows of deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester in the airflow mixing tank 110, thereby achieving full mixing of deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester to obtain a uniformly mixed emulsified water liquid. The third feed pipe 120 is used to sequentially transport deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester.

[0065] In one embodiment, there are two aeration plates, namely a first aeration sub-plate 130 and a second aeration sub-plate 140. The first aeration sub-plate 130 is tilted above the airflow mixing tank 110, and the second aeration sub-plate 140 is tilted below the airflow mixing tank 110. The first aeration sub-plate 130 and the second aeration sub-plate 140 are staggered to ensure that the first aeration sub-plate 130 and the second aeration sub-plate 140 can form two staggered airflows above and below the airflow mixing tank 110, thereby achieving more complete mixing of deionized water, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate and linear polyglycerol ester.

[0066] It can be understood that when the first aeration sub-disc 130 and the second aeration sub-disc 140 are used to perform the airflow mixing operation at the same time, the components in the airflow mixing tank will collide violently, which may easily cause pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate, linear polyglycerol ester and deionized water to generate more bubbles under a higher airflow. Therefore, in one embodiment, in the step of placing the modified emulsifier and deionized water into the airflow mixing tank of the mixing device for mixing, the first aeration sub-disc 130 and the second aeration sub-disc 140 are used to alternately mix intermittently for 5 minutes to 10 minutes to achieve comprehensive airflow mixing of the powdered sodium dodecyl sulfate and linear polyglycerol ester, thereby ensuring that the components in the airflow mixing tank are effectively tumbled.

[0067] Specifically, the alternating intermittent mixing of the first aeration sub-disc 130 and the second aeration sub-disc 140 includes the following specific steps:

[0068] First, the first aeration sub-disc 130 and the second aeration sub-disc 140 are started simultaneously, and aeration is continued for 0.5 min to 2 min to achieve comprehensive airflow mixing of the powdered sodium dodecyl sulfate and linear polyglycerol ester, thereby ensuring that the components in the airflow mixing tank are effectively tumbled; then the second aeration sub-disc 140 and the first aeration sub-disc 130 are alternately operated intermittently for 1 min to 3 min; the cycle is continuously repeated multiple times, so that the total time for the alternating intermittent mixing of the first aeration sub-disc 130 and the second aeration sub-disc 140 is 5 min to 10 min, so as to weaken the mixed airflow in the airflow mixing tank, so that the powdered sodium dodecyl sulfate and linear polyglycerol ester can be better dissolved and dispersed in deionized water, pentaerythritol triacrylate and octylphenol polyoxyethylene ether, and the generation of more bubbles is effectively avoided.

[0069] In one embodiment, in the step of simultaneously starting the first aeration sub-disk 130 and the second aeration sub-disk 140 and continuously aerating for 0.5 min to 2 min, the gas output of the plurality of first aeration heads 131 of the first aeration sub-disk 130 is 1.0 m 3 / h~2.0m 3 / h; the gas output of the second aeration heads of the second aeration sub-disk 140 is 3.0m 3 / h~5.0m 3 / h; to ensure that the aeration volume of the second aeration head is greater than the aeration volume of the first aeration head 131, to achieve positive mixing of the airflow mixing tank; thereby ensuring that the first aeration sub-disc 130 and the second aeration sub-disc 140 can form a better mixed circulating airflow when running simultaneously.

[0070] In one embodiment, in the step of alternately intermittently operating the second aeration sub-disc 140 and the first aeration sub-disc 130 for 1 min to 3 min, the following specific steps are included: firstly, the first aeration sub-disc 130 is closed, and the second aeration sub-disc 140 is allowed to perform aeration operation, and the single gas outlet time of the second aeration sub-disc 140 is controlled to be 5s to 10s, and the gas outlet volume is 5.0m 3 / h~6.0m 3 / h; the single closing time is 2s~5s; then close the second aeration sub-disc 140, start the intermittent aeration of the first aeration sub-disc 130, and control the intermittent conditions of the first aeration sub-disc 130 as follows: the single gas outlet time of the first aeration sub-disc 130 is 10s~20s, and the gas outlet volume is 3.0m 3 / h~4.0m 3 / h; the single closing time is 2s~5s, and the cycle is run multiple times to ensure that the components in the air flow mixing tank can be mixed more fully and comprehensively, and bubbles are not easily generated. It also avoids the problem that the traditional built-in stirring parts cause a large shear force on octylphenol polyoxyethylene ether, sodium dodecyl sulfate, and linear polyglycerol ester, resulting in a high permeability of the finally prepared new water-based hot melt adhesive and causing the composite leather to harden.

[0071] In one embodiment, the first aeration sub-disc 130 is formed with a plurality of first aeration heads 131, and the aeration direction of each of the first aeration heads 131 is inclined downward, and the second aeration sub-disc 140 is formed with a plurality of second aeration heads, and the aeration direction of each of the second aeration heads is inclined upward, so that the first aeration sub-disc 130 and the second aeration sub-disc 140 are used in coordination to achieve more effective churning of the components in the airflow mixing tank.

[0072] In one embodiment, the inclination angle between the first aeration sub-disc 130 and the airflow mixing tank is 15°~35°; the inclination angle between the second aeration sub-disc 140 and the airflow mixing tank is 40°~75°, so as to ensure that the first aeration sub-disc 130 and the second aeration sub-disc 140 can have multiple airflows at different levels in the airflow mixing tank, thereby achieving more sufficient and comprehensive mixing of octylphenol polyoxyethylene ether, sodium dodecyl sulfate, linear polyglycerol ester and water.

[0073] It should be noted that, since the principles of achieving aeration by the first aeration sub-disc 130 and the second aeration sub-disc 140 are both existing technologies, in the present disclosure, the first aeration sub-disc 130 and the second aeration sub-disc 140 are not described in detail.

[0074] S103, placing the polyurethane resin, EVA resin emulsion and water-based acrylic resin into the premixing tank of the mixing device for high-temperature heating and mixing to obtain a resin melt for standby use.

[0075] In one embodiment, the high temperature heating mixing condition is 110° C. to 130° C. and the time is 5 min to 20 min.

[0076] S104, feeding the emulsified water liquid and the resin melt into the stirring tank of the mixing device at the same time, and controlling the emulsified water liquid and the resin melt to intersect and mix during the spraying process.

[0077] It should be noted that, in actual applications, in order to avoid the shear effect of the built-in stirring element on the particle size of the new water-based hot melt adhesive, resulting in a large content of small molecule materials and high permeability of the water-based hot melt adhesive, ultrasonic oscillation or airflow is usually used in combination with a stirring element. However, ultrasonic oscillation will cause the water-based hot melt adhesive to depolymerize, resulting in the presence of more small molecule materials in the traditional water-based hot melt adhesive, resulting in high permeability of the water-based hot melt adhesive and causing the flexibility of the composite leather to become harder; and when the airflow is combined with the stirring element, the stirring force strength is likely to cause the presence of more small molecule materials or more bubbles in the traditional water-based hot melt adhesive.

[0078] Therefore, in the present disclosure, the emulsified water and the resin melt are prepared separately to achieve effective preliminary mixing and emulsification of the emulsified water and the resin melt; the shear force of the modified emulsifier is also reduced to achieve preliminary mixing and emulsification of the emulsified water and the resin melt, effectively reducing the subsequent stirring speed and stirring time, thereby effectively avoiding the phenomenon of over-emulsification or very small particle size shearing of the new water-based hot melt adhesive during the mixing and stirring process, effectively ensuring that the new water-based hot melt adhesive has good bonding performance and low permeability; thereby effectively avoiding the problem of the new water-based hot melt adhesive containing too many small molecular materials penetrating into the leather base material and causing the composite leather to harden.

[0079] It is worth mentioning that since the temperature of the resin melt is relatively high after dissolution, when the emulsified water and the resin melt intersect and mix during the spraying process, the resin melt can use its own waste heat temperature to achieve initial mixing and emulsification with the emulsified water, which not only improves the heat utilization rate, but also ensures the mixing and emulsification effect of the resin melt and the emulsified water, so that the subsequent low-to-medium speed mixing can achieve full mixing and emulsification of the resin melt and the emulsified water, thereby ensuring the preparation of a new water-based hot melt adhesive with better stability, uniform mixing system, better fluidity and less small molecule materials.

[0080] Specifically, Figure 3 and Figure 4 As shown, in one embodiment, the mixing device 10 includes a stirring tank 310, a first feeding pipe 340 and a second feeding pipe 350; the first feeding pipe 340 is used to convey the emulsified water liquid; the second feeding pipe 350 is used to convey the resin melt, the first feeding pipe 340 and the second feeding pipe 350 are located above the stirring tank 310, and are respectively connected to the stirring tank 310; the spraying direction of the first feeding pipe 340 and the discharge direction of the second feeding pipe 350 form a preset angle; so that the emulsified water liquid and the resin melt can intersect and mix during the spraying process.

[0081] Furthermore, if Figure 5 and Figure 6 As shown, in one embodiment, since a spoiler 400 is provided in the first feed pipe 340, the spoiler 400 is connected to the first feed pipe 340, and a plurality of conical nozzles 410 are formed on a side of the spoiler 400 facing away from the first feed pipe 340, the emulsified water can be dispersed by the spoiler 400 when spraying, so that the dispersed emulsified water can be fully mixed with the resin melt.

[0082] S105, under vacuum conditions, the emulsified aqueous solution and the resin melt are mixed alternately at low and medium speeds to obtain a resin emulsion.

[0083] It should be noted that if the emulsified water and the resin melt continue to be mixed with air flow, it is easy to cause the resin melt to generate more bubbles and affect the adhesion of the new water-based hot melt adhesive. If high-speed mixing is used, there is a phenomenon that the new water-based hot melt adhesive is over-emulsified or the particle size is sheared very small during the mixing and stirring process. Therefore, in the present disclosure, the emulsified water and the resin melt are alternately mixed at low and medium speeds under vacuum conditions to achieve secondary mixing of the emulsified water and the resin melt, so that the moisture of the emulsified water and the resin melt can be effectively removed under vacuum conditions, thereby ensuring that the new water-based hot melt adhesive with a uniform mixing system, good fluidity and less small molecular materials is obtained, effectively ensuring that the new water-based hot melt adhesive has good bonding properties and low permeability; thereby effectively avoiding the problem of the new water-based hot melt adhesive containing too many small molecular materials penetrating into the leather base material and causing the composite leather to harden. It is worth mentioning that the use of low-medium speed alternating mixing can effectively reduce the shear strength of the new water-based hot melt adhesive and better ensure the emulsification effect of the new water-based hot melt adhesive, thereby preparing a new water-based hot melt adhesive with better stability, uniform mixing system, better fluidity and less small molecule materials.

[0084] In one embodiment, the vacuum condition is 0.10-0.50 MPa.

[0085] In one embodiment, the conditions for alternating low- and medium-speed mixing are: first, stir at a medium speed of 1000 r / min to 1200 r / min for 2 min to 5 min; then stir at a low speed of 200 r / min to 600 r / min for 5 min to 8 min, and alternately cycle stirring for 3 to 10 times to achieve sufficient and comprehensive mixing of the emulsified water and the resin melt, thereby ensuring that a new water-based hot melt adhesive with a uniform mixing system, good fluidity and less small molecule materials is obtained.

[0086] S106, adding a thermosensitive delayed amine catalyst to the resin emulsion and mixing them at room temperature to obtain the novel water-based hot melt adhesive.

[0087] It can be understood that after the resin melt is mixed with the emulsified water at low and medium speeds in step S105, the temperature of the mixed resin emulsion will slowly drop until the resin emulsion drops to room temperature, and then the thermosensitive delayed amine catalyst is added to the resin emulsion for mixing at room temperature. In this way, the thermosensitive delayed amine catalyst and the resin emulsion will not catalyze when mixed, thereby ensuring that the added thermosensitive delayed amine catalyst can play a better catalytic role in the subsequent heating and pressing operation to achieve rapid bonding between the fabric to be pressed and the leather base material; it also ensures that the resin emulsion is fully and comprehensively mixed and emulsified.

[0088] In one embodiment, the thermosensitive delay amine catalyst is a polyphenol thermosensitive delay catalyst, so as to ensure that the addition of a small amount of polyphenol thermosensitive delay catalyst can delay the curing process of the polyurethane resin, thereby effectively inhibiting the curing speed of the new water-based hot melt adhesive during the spraying process, so as to ensure that the new water-based hot melt adhesive can maintain good fluidity during the spraying process, which is beneficial to the subsequent spraying process, thereby ensuring that a thin, uniform, low-permeability, good adhesion and good softness new water-based environmentally friendly hot melt adhesive layer is obtained on the glue coating surface of the leather base material.

[0089] In a preferred embodiment, the polyphenol thermal delay catalyst is an ECOADD polyphenol thermal delay catalyst. Since the ECOADD polyphenol thermal delay catalyst has good environmental protection, fluidity, and relatively high viscosity, it can have a good wetting effect on the leather base material, which is beneficial to the better spreading of the new water-based hot melt adhesive on the cowhide leather base material to ensure the preparation of composite leather with good softness and strong adhesion, and also ensures that the new water-based hot melt adhesive is not easy to solidify during the subsequent spraying process, which is beneficial to the flow of the new water-based environmentally friendly hot melt adhesive on the leather surface and is not prone to nozzle clogging, so as to ensure the preparation of a thin, uniform, low-permeability, good adhesion and good softness water-based environmentally friendly hot melt adhesive layer.

[0090] It should be noted that the water-based hot melt adhesives currently on the market are generally acrylic acid-based, and acrylic acid-based water-based hot melt adhesives use water as a medium, which effectively solves the problem that traditional organic solvents are easy to volatilize and are not environmentally friendly. Therefore, acrylic acid-based water-based hot melt adhesives are popular among many leather goods factories. However, in actual applications, for some high-end leather products, such as high-end ladies' handbags, when using the commercial acrylic acid-based water-based hot melt adhesive for bonding, the leather base material is prone to hardening, which affects the flexibility of the high-end ladies' handbags.

[0091] To this end, the applicant has conducted an in-depth analysis of various types of acrylic water-based hot melt adhesives on the market and believes that the main problem that causes the leather base material of high-end leather goods to harden is due to the penetration of small molecular materials in traditional water-based hot melt adhesives into the leather base material, that is, the high permeability of traditional water-based hot melt adhesives, which causes the problem of hardening of the leather base material.

[0092] In order to find a new type of water-based hot melt adhesive, in the mixing method of the new water-based hot melt adhesive disclosed in the present invention, firstly, the traditional emulsifier is improved, and the molecular weight is increased relative to the traditional emulsifier, thereby optimizing the proportion of small molecule materials in the new water-based hot melt adhesive. Secondly, the mixing method of the modified emulsifier is also improved, through the mixing method of airflow mixing-intersection mixing-low and medium speed alternation, so as to effectively reduce the subsequent stirring speed and stirring time; so that the subsequent emulsified water liquid and the resin melt can be fully mixed and stirred by low and medium speed alternating mixing, without the need for high-speed mixing, thus effectively avoiding the phenomenon of over-emulsification or particle size being sheared very small during the mixing and stirring process of the new water-based hot melt adhesive, effectively ensuring that the new water-based hot melt adhesive has good bonding performance and low permeability; thereby effectively avoiding the problem of the new water-based hot melt adhesive containing too many small molecule materials penetrating into the leather base material and causing the composite leather to harden.

[0093] It should also be noted that in actual applications, due to the fast curing speed of traditional water-based hot melt adhesive, it is easy to solidify during the subsequent glue spraying process, which is not conducive to the flow of water-based environmentally friendly hot melt adhesive on the leather surface, especially for some composite leathers with less glue coating, this solidification phenomenon is more obvious. Therefore, adding 1 to 3 parts of thermal-sensitive delayed amine catalyst can effectively delay the curing time of the new water-based hot melt adhesive to ensure that the glue nozzle is not prone to clogging, and is conducive to the preparation of a thin, uniform, low-permeability, good adhesion and good softness new water-based hot melt adhesive layer on the glue-coated surface of the leather base material, and it is convenient for composite leather manufacturers to prepare for production in advance for large orders, so as to better meet the production delivery period of large orders in the e-commerce market.

[0094] Furthermore, since the thermosensitive delayed amine catalyst is added to the resin emulsion and mixed at room temperature, it is ensured that the thermosensitive delayed amine catalyst will not catalyze due to high temperature during the mixing and stirring process, so as to ensure that the added thermosensitive delayed amine catalyst will play a stronger catalytic role in the subsequent heating and pressing operation, so as to achieve rapid bonding of the fabric to be pressed and the leather base material, and at the same time, it also avoids the phenomenon that the stirring parts are easily adhered due to the catalytic effect of the thermosensitive delayed amine catalyst in the mixing process.

[0095] In order to achieve better mixing of new water-based hot melt adhesives, such as Figures 2 to 5As shown, in one embodiment, the mixing device 10 includes a first premixing component 100, a second premixing component 200 and a stirring component 300; the first premixing component 100 includes an airflow mixing tank 110, a third feed pipe 120, a first aeration sub-disc 130 and a second aeration sub-disc 140; the third feed pipe 120 is connected to the airflow mixing tank 110, the first aeration sub-disc 130 is tilted above the airflow mixing tank 110, the second aeration sub-disc 140 is tilted below the airflow mixing tank 110, and the first aeration sub-disc 130 and the second aeration sub-disc 140 are staggered; The second premixing assembly 200 includes a premixing tank 210, a fourth feed pipe 220, a first stirring member 240, a heating member (not shown) and a first driver 230; the fourth feed pipe 220 is connected to the premixing tank 210, the first stirring member 240 is rotatably arranged in the premixing tank 210, the heating member is arranged around the peripheral wall of the premixing tank 210 to achieve more comprehensive heating of the premixing tank 210, the first driver 230 is arranged above the premixing tank 210, and the driving end of the first driver 230 is connected to the first stirring member 240 to achieve the driving connection of the first driver 230 to the first stirring member 240.

[0096] Furthermore, the stirring assembly 300 includes a stirring tank 310, a second driver 320, a second stirring member 330, a first feed pipe 340, a second feed pipe 350 and a fifth feed pipe 360, wherein the first feed pipe 340 and the second feed pipe 350 are located above the stirring tank 310, the first end of the first feed pipe 340 is connected to the outlet end of the airflow mixing tank 110, and the second end of the first feed pipe 340 is connected to the first feed end of the stirring tank 310, thereby realizing the connection setting between the airflow mixing tank 110 and the stirring tank 310, thereby ensuring that the emulsified water in the airflow mixing tank 110 can be transported to the first feed pipe 340 of the stirring tank 310, and then sprayed out by the first feed pipe 340, thereby completing the transportation of the emulsified water; and since the second end of the second feed pipe 350 is connected to the outlet end of the premixing tank 210 , and the second end of the second feed pipe 350 is connected to the second feed end of the stirring tank 310, realizing the connection setting between the premixing tank 210 and the stirring tank 310, thereby ensuring that the resin melt in the premixing tank 210 can be transported to the second feed pipe 350 of the stirring tank 310, and then sprayed out by the second feed pipe 350, thereby completing the transportation of the resin melt; the fifth feed pipe 360 ​​is connected and arranged above the stirring tank 310, and the fifth feed pipe 360 ​​is used to transport the thermal sensitive delayed amine catalyst; and because the spraying direction of the first feed pipe 340 and the discharge direction of the second feed pipe 350 form a preset angle; so that the emulsified water and the resin melt can intersect and mix during the spraying process; the second stirring member 330 is rotatably arranged in the stirring tank 310, and the driving end of the second driver 320 is connected to the second stirring member 330.

[0097] It can be understood that, since the first aeration sub-disc 130 is tiltedly arranged above the airflow mixing tank 110, the second aeration sub-disc 140 is tiltedly arranged below the airflow mixing tank 110, and the first aeration sub-disc 130 and the second aeration sub-disc 140 are staggered, a comprehensive airflow mixing operation of the deionized water and the modified emulsifier can be achieved; and since the first stirring member 240 is rotatably arranged in the premixing tank 210, the heating member is arranged around the peripheral wall of the premixing tank 210 to achieve a more comprehensive heating of the premixing tank 210, the first driver 230 is arranged above the premixing tank 210, and the first driver 230 is arranged above the premixing tank 210. The driving end of the device 230 is connected to the first stirring member 240, so as to achieve more comprehensive high-temperature heating and mixing of the polyurethane resin, EVA resin emulsion and water-based acrylic resin; and because the spraying direction of the first feed pipe 340 and the discharge direction of the second feed pipe 350 form a preset angle; so that the emulsified water and the resin melt can intersect and mix during the spraying process; and because the fifth feed pipe 360 ​​is connected and arranged above the stirring tank 310, the thermosensitive delayed amine catalyst can be added to the resin emulsion in the stirring tank 310 through the fifth feed pipe 360 ​​for room temperature mixing operation.

[0098] In one embodiment, the total projection area of ​​the spoiler 400 is located in the discharge direction of the second feed pipe 350, so that the emulsified water liquid sprayed out of the spoiler 400 can fall more comprehensively in the discharge direction of the second feed pipe 350, thereby ensuring a more effective initial mixing and emulsification effect of the emulsified water liquid and the resin melt.

[0099] In one of the embodiments, when controlling the intersection and mixing of the emulsified water liquid and the resin melt during the spraying process, the starting point of the intersection and mixing is set near the discharge port of the second feed pipe 350 to ensure that the sprayed emulsified water liquid can be fully and fully mixed at the moment the resin melt just comes out, thereby better ensuring the initial mixing and emulsification effect of the emulsified water liquid and the resin melt.

[0100] In one embodiment, the first feed pipe 340 is tilted on the stirring tank 310, and the second feed pipe 350 is vertically disposed on the stirring tank 310, so as to achieve better and comprehensive preliminary mixing and emulsification of the emulsified water liquid and the resin melt. In one embodiment, the spraying direction of each of the conical nozzles 410 is tilted downward, so that the pressure of the sprayed emulsified water liquid is relatively large, so that the sprayed emulsified water liquid can be well injected into the interior of the resin melt that has just flowed out, and then under the action of gravity, the emulsified water liquid can be better preliminarily mixed and emulsified with the resin melt.

[0101] In one embodiment, the conical nozzles 410 are arranged in a straight line along the discharge direction of the second feed pipe 350, so that the ejected emulsified water liquid can fall more comprehensively on the resin melt in the discharge direction, thereby achieving sufficient and comprehensive preliminary mixing and emulsification of the emulsified water liquid and the resin melt.

[0102] like Figure 4 As shown, in one embodiment, the spoiler 400 has a vertical inclined surface and an arc portion, the vertical inclined surface is parallel to the discharge direction of the second feed pipe 350, and the first conical nozzle 410 close to the discharge port of the second feed pipe 350 is arranged adjacent to the discharge port of the second feed pipe 350, so as to better achieve sufficient and comprehensive preliminary mixing and emulsification of the emulsified water and the resin melt, and maximize the utilization rate of the residual heat temperature of the resin melt itself.

[0103] In one embodiment, the plurality of conical nozzles spray liquid alternately, so that the emulsified water liquid can be better initially mixed and emulsified with the resin melt. Specifically, the conditions for alternate spraying liquid are: when one of the two adjacent conical nozzles is operated for 2s to 5s and then closed, the other one is operated for 2s to 5s after being closed, and the alternate operation is repeated in this way to achieve sufficient and comprehensive initial mixing and emulsification of the emulsified water liquid and the resin melt.

[0104] In order to achieve sufficient and comprehensive preliminary mixing and emulsification of the emulsified aqueous liquid and the resin melt, in one embodiment, the spraying time of the emulsified aqueous liquid is controlled to be consistent with the discharge time of the resin melt, so as to better ensure more sufficient and comprehensive preliminary mixing and emulsification of the emulsified aqueous liquid and the resin melt.

[0105] In one embodiment, the first feed pipe is obliquely arranged on the stirring tank, the second feed pipe is vertically arranged on the stirring tank, and the extension direction of the first feed pipe and the extension direction of the second feed pipe form a preset angle, which is an obtuse angle. Specifically, the degree of the obtuse angle is 105° to 135°, so as to ensure that the emulsified water sprayed from the first feed pipe can better enter the interior of the resin melt.

[0106] In one embodiment, the first feed pipe is provided with an extraction pump and a control valve to realize the spraying setting of the emulsified water liquid.

[0107] In one embodiment, the stirring assembly also includes a vacuum exhaust assembly, and the exhaust pipe of the vacuum exhaust assembly is connected to the exhaust port of the stirring tank to realize the vacuum operation of the stirring tank, effectively removing the oxygen in the stirring tank to ensure that the emulsified water and the resin melt are not easily oxidized during the stirring process.

[0108] The present disclosure also provides a novel water-based hot melt adhesive, which is prepared by the mixing method of the novel water-based hot melt adhesive described in any of the above embodiments.

[0109] It can be understood that by adopting the mixing device disclosed in the present invention, the added 35-50 parts of EVA resin emulsion, 30-40 parts of water-based acrylic resin; 40-50 parts of polyurethane resin; 1-3 parts of heat-sensitive delayed amine catalyst, 3.5-7 parts of modified emulsifier, and 20-25 parts of deionized water can achieve separate mixing of emulsified water and resin melt during the mixing operation, and then the first feed pipe is inclined and the second feed pipe is vertically set, so that the emulsified water and the resin melt can be fully and fully mixed and emulsified during the spraying process, thereby effectively reducing the subsequent stirring speed and stirring shear force. At the same time, the added 1-3 parts of heat-sensitive delayed amine catalyst effectively delays the rapid solidification of the water-based environmentally friendly hot melt adhesive during the spraying process, which is conducive to the preparation of a thin, uniform, low-permeability, good adhesion and good softness water-based environmentally friendly hot melt adhesive layer to better meet the flexibility requirements of high-end women's bags.

[0110] The present disclosure also provides a composite leather production method, comprising the following steps: obtaining a leather base material; wherein the leather base material comprises a surface and a glue-coated surface; delivering the leather base material to the bottom of the glue-spraying component of the automatic glue-spraying equipment through a conveying component of the automatic glue-spraying equipment; the glue-spraying component applies the novel water-based hot melt adhesive of any of the above embodiments on the glue-coated surface of the leather base material to obtain a glue-leather layer; naturally ventilating and drying the glue-leather layer for use; bonding the fabric to be pressed with the glue-leather layer to obtain leather A to be pressed; and heating and pressing the leather A to be pressed to obtain the composite leather.

[0111] The above-mentioned composite leather production method adopts the new water-based hot melt adhesive disclosed in the present invention, so that the coated glue-leather layer can be dried under natural ventilation conditions, and the glue-leather layer can be dried without additional heating, which not only reduces the drying energy consumption, but also effectively avoids the shrinkage, deformation or yellowing of the leather base material due to excessive temperature, thereby ensuring that the composite leather finally prepared will not show yellowing or shrinkage, etc., and it is convenient for composite leather manufacturers to make production preparations in advance for large orders; thereby ensuring the short-term production and delivery of large orders to better meet the purchasing needs of buyers and effectively avoid the phenomenon of large-scale returns.

[0112] A method for making composite leather in one embodiment includes some or all of the following steps:

[0113] S201, obtaining a leather base material; wherein the leather base material comprises a surface and a rubber-coated surface. The leather base material can be cowhide leather or artificial leather. In some preferred embodiments, the leather base material is cowhide leather to meet the application of high-end women's bags in the market.

[0114] S202, conveying the leather base material to the bottom of the glue spraying assembly of the automatic glue spraying equipment through the conveying assembly of the automatic glue spraying equipment. It can be understood that the leather base material is placed on the conveyor belt with the glue-coated surface of the leather base material facing upward, and then conveyed to the bottom of the glue spraying assembly of the automatic glue spraying equipment through the conveyor belt, so as to complete the automatic glue spraying operation later.

[0115] S203, the glue spraying component applies the novel water-based hot melt adhesive of any of the above embodiments onto the glue-coated surface of the leather base material to obtain a glue-leather layer.

[0116] It can be understood that since the glue spray head of the glue spray assembly is connected to the stirring tank of the mixing device through the glue storage tank, the new water-based hot melt adhesive prepared in the stirring tank can enter the glue storage tank and then be automatically sprayed onto the glue-coated surface of the leather base material through the glue spray head.

[0117] S204, air-drying the glue-leather layer by natural ventilation for standby use. It can be understood that by air-drying the glue-leather layer by natural ventilation, the glue-leather layer can be dried without additional heating, which not only reduces the energy consumption of drying, but also effectively avoids the problem of shrinkage, deformation or yellowing of the leather base material due to excessive temperature, thereby ensuring the quality of the composite leather. It is also convenient for composite leather manufacturers to prepare for production in advance for large orders, so as to better meet the production delivery period of large orders in the e-commerce market.

[0118] S205, laminating the fabric to be pressed with the glue-leather layer to obtain leather to be pressed A. Specifically, leather goods manufacturers can select suitable fabric to be pressed according to actual production needs, such as ear paper, fabric lining, microfiber strong cloth, etc.

[0119] It should be noted that, with the continuous development of the e-commerce market, when new women's bags are welcomed by a large number of consumers, large orders will be generated. Large orders will bring great pressure to the production of leather goods manufacturers. If the products are not delivered quickly, the market is prone to a large number of returns. Therefore, in order to avoid the above problems, in the present disclosure, the leather base material is processed in S201~S204 to obtain a naturally ventilated and dried glue-leather layer for standby use, that is, the raw materials are prepared in advance. When a large order is received, the leather manufacturer can directly use the glue-leather layer to enter the S205 step, so that the leather manufacturer can select the appropriate pressing fabric according to the production requirements, so as to quickly produce the composite leather required for high-end women's bags, effectively shorten the production cycle, reduce the production pressure of leather manufacturers, and quickly complete the short-term production and delivery of large orders to better meet the purchase needs of buyers and effectively avoid the phenomenon of large returns.

[0120] S206, performing a heating and pressing operation on the leather to be pressed A to obtain the composite leather.

[0121] It can be understood that by performing a heating and pressing operation on the leather A to be pressed, the glue coated on the leather A to be pressed can well bond the surface material to be pressed and the leather base material together under heating conditions, so as to quickly obtain a composite leather with good adhesion and softness.

[0122] In one of the embodiments, the heating and pressing operation conditions are 70°C to 75°C and the time is 2S to 15S. On the one hand, it avoids the problem of shrinkage, yellowing or shrinkage of the composite leather caused by the heating and pressing temperature being too high; on the other hand, it ensures that the surface to be pressed and the leather base material can fit well to obtain a smooth, well-adhesive and soft composite leather.

[0123] In one embodiment, the composite leather is cut and glued according to the design of the high-end women's bag to prepare the high-end women's bag required for production.

[0124] The present application also provides a composite leather obtained by the composite leather manufacturing method described in any of the above embodiments. It can be understood that due to the use of the new water-based hot melt adhesive disclosed in the present invention, the new water-based hot melt adhesive coated on the leather base material has low permeability, which effectively avoids the problem of the composite leather becoming hard due to excessive small molecular materials contained in the new water-based hot melt adhesive penetrating into the leather base material, and avoids the composite leather from yellowing or shrinking, etc.; thereby ensuring that a smooth, adhesive, soft, non-yellowing and non-shrinking composite leather is obtained, so as to better meet the application of high-end women's bags.

[0125] Compared with the prior art, the present invention has at least the following advantages:

[0126] 1) The modified emulsifier and deionized water are placed in the air flow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution, so as to ensure that the hydrophilic end of the modified emulsifier can be well dispersed on the water interface, so that the emulsified aqueous solution can subsequently quickly enter the resin melt to achieve a more uniform dispersion; at the same time, the polyurethane resin, EVA resin emulsion and water-based acrylic resin are placed in the premixing tank of the mixing device for high-temperature heating and mixing to obtain a resin melt; the emulsified aqueous solution and the resin melt are prepared separately; and because the mixing device includes a stirring tank, a first feeding pipe and a second feeding pipe; the first feeding pipe is used to transport the emulsified aqueous solution; the second feeding pipe is used to transport the resin melt, the first feeding pipe and the second feeding pipe are located above the stirring tank and are respectively connected to the stirring tank; so that the mixing device can simultaneously feed the emulsified aqueous solution and the resin melt into the stirring tank, and because the spraying direction of the first feeding pipe and the discharge direction of the second feeding pipe form a preset angle, and the disturbance A plurality of conical nozzles are formed on one side of the flow member away from the first feed pipe, so that the emulsified water liquid can be dispersed by the spoiler when spraying, so that the dispersed emulsified water liquid can be fully mixed with the resin melt, and the emulsified water liquid and the resin melt can intersect and mix during the spraying process, so that the resin melt can use its own waste heat temperature to achieve preliminary mixing and emulsification with the emulsified water liquid, which not only improves the utilization rate of the waste heat of the resin melt, but also ensures the preliminary mixing and emulsification effect of the resin melt and the emulsified water liquid, and effectively reduces the subsequent stirring speed and stirring time, that is, the subsequent emulsified water liquid and the resin melt only need to be mixed alternately at low and medium speeds to achieve sufficient mixing and stirring, without the need for high-speed mixing. In this way, the new water-based hot melt adhesive can be effectively prevented from being over-emulsified or the particle size being sheared very small during the mixing and stirring process, and the new water-based hot melt adhesive can be effectively ensured to have good bonding performance and low permeability; thereby effectively avoiding the problem of the new water-based hot melt adhesive containing too many small molecular materials penetrating into the leather base material and causing the composite leather to harden.

[0127] 2) Since the addition of the thermal-sensitive delayed amine catalyst can effectively inhibit the curing speed of the new water-based hot melt adhesive during the spraying process, it ensures that the new water-based hot melt adhesive can maintain good fluidity during the spraying process, which is beneficial to the subsequent spraying process, thereby ensuring that a thin, uniform, low-permeability, good adhesion and good softness of the new water-based environmentally friendly hot melt adhesive layer is obtained on the glue-coated surface of the leather base material. In addition, the added thermal-sensitive delayed amine catalyst prolongs the curing time, so that the composite leather manufacturer can make advance production preparations for large orders to better meet the production delivery period of large orders in the e-commerce market. Since the thermal-sensitive delayed amine catalyst is added to the resin emulsion for mixing at room temperature, it is ensured that the thermal-sensitive delayed amine catalyst will not catalyze due to high temperature during the mixing and stirring process, so as to ensure that the added thermal-sensitive delayed amine catalyst will play a stronger catalytic role in the subsequent heating and pressing operation, so as to achieve rapid bonding between the fabric to be pressed and the leather base material, and at the same time, it also avoids the phenomenon that the stirring parts are easily adhered due to the catalytic effect of the thermal-sensitive delayed amine catalyst in the mixing process.

[0128] 3) Compared with the traditional general emulsifier, the modified emulsifier disclosed in the present invention includes at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfonate and linear polyglycerol ester, and has a larger molecular weight than the traditional general emulsifier, so as to increase the molecular weight of the modified emulsifier itself, and effectively avoid the problem that the traditional water-based hot melt adhesive has more small molecular materials, resulting in its high permeability and affecting the flexibility of the composite leather; and ensure that the various components of the modified emulsifier can play a good synergistic role, so that the emulsified water can quickly enter the resin melt, so as to better ensure the emulsification effect of the new water-based hot melt adhesive.

[0129] Some specific examples are given below, and if % is mentioned, it means percentage by weight. It should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial sources unless otherwise specified.

[0130] It should be noted that EVA resin emulsion (EVA emulsion-CP149, manufacturer Zhongshan Dixin Chemical Co., Ltd.), water-based acrylic resin (model SEACRYL 11K40, manufacturer Guangdong Xidun New Material Technology Co., Ltd.), polyurethane resin (model 9009-54-5, manufacturer Guangdong Bangding Resin Products Co., Ltd.), polyphenol thermal delay catalyst (Ye Innovation Materials (Shanghai) Co., Ltd. provides model ECOADD ®80500), pentaerythritol triacrylate (model L-61030, manufacturer Guangdong Sanqi New Materials Co., Ltd.), octylphenol polyoxyethylene ether (octylphenol polyoxyethylene ether OP-15, manufacturer Tianjin Hongtaiyang Chemical Co., Ltd.), sodium dodecyl sulfonate (sodium dodecyl sulfonate P60, manufacturer Guangzhou Taili Chemical Co., Ltd.), linear polyglycerol ester (polyglycerol-10 oleate 79665-93-3, manufacturer Wuhan Kamik Technology Co., Ltd.)

[0131] Table 1 Recipe

[0132]

[0133] The formulations of Examples 1 to 3, 5 to 8 in Table 1 were prepared according to the following steps:

[0134] S101, preparing various materials according to the formula of the novel water-based hot melt adhesive in Table 1;

[0135] S102, placing the modified emulsifier and deionized water into the airflow mixing tank 110 of the mixing device 10 for airflow mixing to obtain a uniformly mixed emulsified water liquid;

[0136] The specific steps of the mixed airflow operation include: first, starting the first aeration sub-disc 130 and the second aeration sub-disc 140 at the same time, and continuing aeration for 2 minutes, and controlling the air output of the first aeration heads 131 of the first aeration sub-disc 130 to be 1.0m 3 / h; the gas output of the second aeration heads of the second aeration sub-disk 140 is 3.0m 3 / h; then the second aeration sub-disc 140 and the first aeration sub-disc 130 are alternately operated intermittently for 3 minutes; when the second aeration sub-disc 140 is operated intermittently, the intermittent operation conditions are that the single gas outlet time of the second aeration sub-disc 140 is 5s and the gas outlet volume is 5.0m 3 / h; the single closing time is 3s; then, the second aeration sub-disc 140 is closed, and the first aeration sub-disc 130 is intermittently aerated, and the intermittent conditions of the first aeration sub-disc 130 are controlled as follows: the single gas outlet time of the first aeration sub-disc 130 is 10s, and the gas outlet volume is 3.0m 3 / h; the single closing time is 5s, the inclination angle of the first aeration sub-disc 130 and the airflow mixing tank 110 is 25°; the inclination angle of the second aeration sub-disc 140 and the airflow mixing tank 110 is 45°, and the mixing is alternated for 8min;

[0137] S103, placing polyurethane resin, EVA resin emulsion and water-based acrylic resin into the premixing tank 210 of the mixing device 10 and heating and mixing at 120° C. for 10 minutes to obtain a resin melt;

[0138] S104, feeding the emulsified water liquid and the resin melt into the stirring tank 310 of the mixing device 10 at the same time, and controlling the emulsified water liquid and the resin melt to intersect and mix during the spraying process;

[0139] The first feed pipe 340 of the stirring tank 310 assembly of the mixing device 10 is obliquely arranged on the stirring tank 310, and the second feed pipe 350 is vertically arranged on the stirring tank 310, and the extension direction of the first feed pipe 340 and the extension direction of the second feed pipe 350 form a preset angle, and the preset angle is 105°;

[0140] A spoiler 400 is disposed in the first feed pipe 340, the spoiler 400 is connected to the first feed pipe 340, and a plurality of conical nozzles 410 are formed on a side of the spoiler 400 away from the first feed pipe 340, and each of the conical nozzles 410 is arranged in a straight line along the discharge direction of the second feed pipe 350; and the starting point of intersection and mixing is arranged adjacent to the discharge port of the second feed pipe 350;

[0141] S105, under a vacuum condition of 0.50 MPa, the emulsified aqueous solution and the resin melt are mixed alternately at low and medium speeds to obtain a resin emulsion; wherein the conditions for the alternating mixing at low and medium speeds are: first, stirring at a medium speed of 1000 r / min for 5 min; then stirring at a low speed of 800 r / min for 8 min; and this alternating cycle is repeated 8 times;

[0142] S106, after the resin melt is mixed with the emulsified water at low and medium speeds in step S105, until the resin emulsion cools to room temperature, a thermosensitive delayed amine catalyst is added to the resin emulsion and mixed at room temperature to obtain a novel water-based hot melt adhesive.

[0143] The difference between the preparation methods of Example 4 and Example 1 is that Example 4 omits step S106.

[0144] The difference between the preparation methods of Comparative Example 1 and Example 4 is that:

[0145] Comparative Example 1 is prepared by high-speed stirring using a conventional mixing device, i.e., steps S102, S104 and S106 are omitted in Comparative Example 1, and the stirring speed of S105 is controlled to be set to high-speed stirring, i.e., the high-speed stirring speed of Comparative Example 1 is 1500 r / min.

[0146] The novel water-based hot melt adhesives of Examples 1 to 8 and Comparative Example 1 prepared above are applied to composite leather, specifically comprising the following steps:

[0147] S201, obtaining a cowhide leather base material; wherein the cowhide leather base material comprises a surface and a rubber-coated surface;

[0148] S202, delivering the cowhide leather base material to the bottom of the glue spraying assembly of the automatic glue spraying equipment through the conveying assembly of the automatic glue spraying equipment, so that the glue-coated surface of the cowhide leather base material is disposed toward the glue spraying head of the glue spraying assembly;

[0149] S203, the glue spraying head of the glue spraying assembly applies the novel water-based hot melt adhesive of Examples 1 to 8 obtained above to the glue-coated surface of the cowhide leather base material to obtain a glue-leather layer;

[0150] S204, drying the glue-leather layer by natural ventilation for standby use;

[0151] S205, laminating the surface ear paper to be pressed with the glue-leather layer to obtain leather A to be pressed;

[0152] S206, pressing the leather A to be pressed at 75°C for 5S to obtain the composite leather.

[0153] The composite leathers of Examples 1 to 8 obtained above are applied to bags. Specifically, the composite leathers are cut and glued according to the design of high-end ladies' bags to prepare the high-end ladies' bags required for production.

[0154] The composite leathers of Examples 1 to 8 obtained above were subjected to peeling test, hand feel test and appearance test, and the results are shown in Table 2;

[0155] Among them, the test standard: GB / T 532-2008 is used for peeling test: GB / T 39371-2020 standard is used to test softness. According to the popular classification standard of the leather industry, the grades are: grade 1> grade 2> grade 3> grade 4, and grade 1 is the softest;

[0156] Table 2 Experimental data table

[0157]

[0158] It can be seen from Examples 1 to 3 and Examples 4 to 8 in Table 2 that, due to the combined use of polyphenol thermosensitive delayed catalyst, pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate and linear polyglycerol ester in Examples 1 to 3, the composite leathers prepared in Examples 1 to 3 are significantly better than those in Examples 4 to 8, especially the comprehensive indicators of Example 1 are the best.

[0159] It can be seen from Example 4 and Comparative Example 1 in Table 2 that since Comparative Example 1 adopts a traditional mixing device for high-speed preparation, the new water-based hot melt adhesive finally prepared has a higher content of small molecules, which affects the flexibility of the composite leather, resulting in the appearance inspection and the hair and wire drawing phenomenon of the ear paper of the surface to be pressed after peeling of Comparative Example 1 being worse than those of Example 4.

[0160] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A novel method for mixing water-based hot melt adhesive, wherein a plurality of materials are mixed and emulsified by a mixing device, characterized in that: The steps include: Prepare various materials according to the formula of the novel water-based hot melt adhesive; Putting a modified emulsifier and deionized water into the air flow mixing tank of the mixing device for mixing to obtain an emulsified aqueous solution; wherein the modified emulsifier includes at least three of pentaerythritol triacrylate, octylphenol polyoxyethylene ether, sodium dodecyl sulfate and linear polyglycerol ester; and, Putting polyurethane resin, EVA resin emulsion and water-based acrylic resin into the premixing tank of the mixing device and heating and mixing at a high temperature of 110° C. to 130° C. to obtain a resin melt; The emulsified water liquid and the resin melt are simultaneously fed into the stirring tank of the mixing device, and the emulsified water liquid and the resin melt are controlled to intersect and mix during the spraying process; Wherein, the mixing device comprises a stirring tank, a first feeding pipe and a second feeding pipe; the first feeding pipe is used to convey the emulsified aqueous solution; the second feeding pipe is used to convey the resin melt, the first feeding pipe and the second feeding pipe are located above the stirring tank and are respectively connected to the stirring tank; the spraying direction of the first feeding pipe and the discharge direction of the second feeding pipe form a preset angle; A spoiler is provided in the first feed pipe, the spoiler is connected to the first feed pipe, and a plurality of conical nozzles are formed on a side of the spoiler away from the first feed pipe, so that the emulsified water can be dispersed by the spoiler when spraying; Under vacuum conditions, the emulsified aqueous solution and the resin melt are alternately mixed at low and medium speeds to obtain a resin emulsion; The thermosensitive delayed amine catalyst is added into the resin emulsion and mixed at room temperature to obtain the novel water-based hot melt adhesive.

2. The mixing method of the novel water-based hot melt adhesive according to claim 1, characterized in that: The total injection projection area of ​​the spoiler is located in the discharge direction of the second feed pipe.

3. The mixing method of the novel water-based hot melt adhesive according to claim 1, characterized in that: When the emulsified aqueous liquid and the resin melt are controlled to intersect and mix during the spraying process, the starting point of the intersect and mix is ​​set adjacent to the discharge port of the second feed pipe.

4. The mixing method of the novel water-based hot melt adhesive according to claim 1, characterized in that: The first feed pipe is obliquely arranged on the stirring tank, and the second feed pipe is vertically arranged on the stirring tank.

5. The novel water-based hot melt adhesive mixing method according to claim 1, characterized in that: The spraying direction of each conical nozzle is inclined downward.

6. The novel water-based hot melt adhesive mixing method according to claim 1, characterized in that: The plurality of conical nozzles spray liquid alternately.

7. The novel mixing method of water-based hot melt adhesive according to claim 1, characterized in that: The heat-sensitive delayed amine catalyst is a polyphenol heat-sensitive delayed catalyst.

8. A new type of water-based hot melt adhesive, characterized in that: The novel water-based hot melt adhesive is prepared by the mixing method described in any one of claims 1 to 7.

9. A method for producing composite leather, characterized in that: The steps include: Obtaining a leather base material; wherein the leather base material comprises a surface and a rubber-coated surface; The leather base material is delivered to the bottom of the glue spraying component of the automatic glue spraying equipment through the conveying component of the automatic glue spraying equipment; The glue spraying assembly applies the novel water-based hot melt adhesive of claim 8 to the glue-coated surface of the leather base material to obtain a glue-leather layer; The glue-leather layer is naturally ventilated and air-dried for later use; Laminating the fabric to be pressed with the glue-leather layer to obtain leather A to be pressed; The leather A to be pressed is subjected to heating and pressing operation to obtain the composite leather.

10. A composite leather, characterized in that: The composite leather is obtained by the composite leather production method according to claim 9.

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