A luggage moisture-cured reaction type polyurethane hot melt adhesive and a preparation method thereof

Abstract

The application relates to the field of polyurethane hot melt adhesives, and particularly discloses a luggage wet-curing reaction type polyurethane hot melt adhesive and a preparation method thereof; the luggage wet-curing reaction type polyurethane hot melt adhesive comprises the following raw materials in parts by weight: 10-20 parts of polyether polyol, 40-60 parts of polyester polyol, 20-50 parts of isocyanate, 0.5-1.5 parts of a catalyst, 10-20 parts of tackifying resin, 3-5 parts of a viscosity stabilizer, 1-3 parts of pentaerythritol diacrylate, 5-10 parts of an additive, and 3-5 parts of a coupling agent; the luggage wet-curing reaction type polyurethane hot melt adhesive prepared by the application is prepared by reacting polyether polyol, polyester polyol and isocyanate to generate a polyurethane prepolymer, so that the hot melt adhesive has good flexibility and durability; the tackifying resin, the pentaerythritol diacrylate and the viscosity stabilizer are used to enable the polyurethane hot melt adhesive to have good initial adhesion and final adhesion strength, and the polyurethane hot melt adhesive can form firm adhesion with a base material more quickly.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polyurethane hot melt adhesive, in particular to a luggage moisture-curable reaction type polyurethane hot melt adhesive and a preparation method thereof. BACKGROUND

[0002] Luggage is an indispensable item in daily life, and adhesives are needed for bonding various parts during the manufacturing process. The adhesives commonly used on the market are mostly ordinary polyurethane glue or chloroprene glue, etc. These adhesives can meet certain bonding requirements, but the bonding effect is often poor in a humid environment, and delamination phenomenon is prone to occur.

[0003] Moisture-curable reaction type polyurethane hot melt adhesive (PUR) is a single-component polyurethane adhesive with high viscosity, and its main component is an isocyanate-terminated polyurethane prepolymer, which is generally prepared by reacting isocyanate monomers, various polyether or polyester polyols. Initial adhesion is one of the important performance indicators of luggage adhesives, but traditional PUR hot melt adhesives often have small initial bonding strength and later adhesion, and high temperature rebounding, which cannot meet the use requirements in the luggage field. SUMMARY

[0004] In order to improve the bonding effect of the existing polyurethane hot melt adhesive, the present application provides a luggage moisture-curable reaction type polyurethane hot melt adhesive and a preparation method thereof.

[0005] In the first aspect, the present application provides a luggage moisture-curable reaction type polyurethane hot melt adhesive, which adopts the following technical solution:

[0006] A luggage moisture-curable reaction type polyurethane hot melt adhesive, comprising the following raw materials by weight: polyether polyol 10-20 parts, polyester polyol 40-60 parts, isocyanate 20-50 parts, catalyst 0.5-1.5 parts, tackifying resin 10-20 parts, viscosity stabilizer 3-5 parts, pentaerythritol diacrylate 1-3 parts, additive 5-10 parts, coupling agent 3-5 parts.

[0007] By adopting the above technical scheme, the polyether polyol is used as the soft segment to generate the polyurethane prepolymer with the isocyanate, good flexibility and hydrolysis resistance are provided. The polyester polyol is also used as the soft segment raw material to enhance the heat resistance and chemical resistance of the polyurethane hot melt adhesive, so that the prepared polyurethane hot melt adhesive has good bonding strength. The tackifying resin and the viscosity stabilizer are used to enable the polyurethane hot melt adhesive to maintain good bonding strength for a long time, and improve the late bonding force of the polyurethane hot melt adhesive. The hydroxyl groups and the acrylate groups of the pentaerythritol diacrylate can react with the polyurethane prepolymer to form additional chemical bonds, enhance the cohesive force of the hot melt adhesive, and more quickly form a firm bond when contacting the luggage base material, thereby improving the initial tack and the late bonding strength of the hot melt adhesive. At the same time, the pentaerythritol diacrylate can enable the hot melt adhesive to form a more compact network structure during the curing process, enhance the adhesion between the hot melt adhesive and the base material and the final bonding strength, and improve the durability of the hot melt adhesive.

[0008] Preferably, the viscosity stabilizer is polyphosphoric acid.

[0009] By adopting the above technical scheme, the polyphosphoric acid is used as the viscosity stabilizer, which can reduce the side reaction between the NCO groups in the polyurethane prepolymer and the moisture, thereby stabilizing the bonding strength of the polyurethane hot melt adhesive in a humid environment and improving the bonding strength of the polyurethane hot melt adhesive in the later period.

[0010] Preferably, the coupling agent is one of 3-aminopropyl triethoxysilane, γ-(2,3-epoxypropoxy) propyl trimethyl silane and γ-(methacryloyloxy) propyl trimethyl silane.

[0011] By adopting the above technical scheme, the 3-aminopropyl triethoxysilane, the γ-(2,3-epoxypropoxy) propyl trimethyl silane and the γ-(methacryloyloxy) propyl trimethyl silane are added to the raw material of the polyurethane hot melt adhesive, which can react with the polyurethane prepolymer through active groups such as amino groups, epoxy groups, methacryloyloxy groups and silane groups to form chemical bonds, enhance the cohesive force of the polyurethane hot melt adhesive, and enhance the late bonding force and hydrolysis resistance of the hot melt adhesive.

[0012] Preferably, the coupling agent has an end-capping rate ranging from 13% to 17%.

[0013] By adopting the above technical scheme, adjusting the end-capping rate of the coupling agent within a suitable range can enable the polyurethane hot melt adhesive to have good initial tack and final tack. If the end-capping rate is too low, the melt viscosity of the polyurethane hot melt adhesive is low, and the initial tack is low. If the end-capping rate is too large, the flowability is poor, the melt viscosity is too large, the sizing is difficult, and the final tack is reduced.

[0014] Preferably, the auxiliary agent includes an antioxidant and a leveling agent.

[0015] Preferably, the tackifying resin is one of polyacrylic resin, petroleum resin, and disproportionated rosin resin.

[0016] By using the above technical solution, the polyacrylic resin, petroleum resin, and disproportionated rosin resin are added to the hot melt adhesive raw material as tackifying resin, can form a uniform mixture with the polyurethane prepolymer, has a low softening point, improves the flowability and wettability of the polyurethane hot melt adhesive, enhances the initial tack, heat resistance and chemical resistance of the polyurethane hot melt adhesive, and makes the polyurethane hot melt adhesive better adapt to the bonding of luggage, high-temperature and humid bonding environment. The disproportionated rosin resin can maintain the good curing speed of the hot melt adhesive, improve the cohesive force of the hot melt adhesive, and enhance the bonding durability and final tack strength of the hot melt adhesive.

[0017] Preferably, the disproportionated rosin resin is modified by a compatibilization method, which includes the following specific steps: the disproportionated rosin is preheated and melted under inert gas, then a modified catalyst and a polyol are added to form a reaction liquid, the reaction liquid is heated to 230-250℃ for reaction, and stirred uniformly until the acid value of the reaction liquid remains unchanged, and the modified disproportionated rosin resin is prepared by cooling the reaction liquid.

[0018] By using the above technical solution, the disproportionated rosin resin is modified, the acid value of the disproportionated rosin resin is reduced, and the compatibility of the disproportionated rosin resin with the polyurethane prepolymer is enhanced, which can improve the wettability of the polyurethane hot melt adhesive, and further improve the bonding strength and durability of the hot melt adhesive.

[0019] In the second aspect, the application provides a preparation method of a luggage moisture curing reaction type polyurethane hot melt adhesive, which adopts the following technical solution:

[0020] A preparation method of a luggage moisture curing reaction type polyurethane hot melt adhesive, which includes the following specific steps: polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate, and additives are mixed and melted at 80-120℃, vacuum dewatering is performed, then isocyanate is added under the protection of nitrogen for heating reaction, and finally catalyst and coupling agent are added for heat preservation reaction, to prepare the luggage moisture curing reaction type polyurethane hot melt adhesive.

[0021] By using the above technical solution, the prepared polyurethane hot melt adhesive has good initial tack strength and final tack strength, can better adapt to the bonding of luggage, high-temperature and humid bonding environment, and has good bonding durability.

[0022] Preferably, the reaction temperature is 100-120℃.

[0023] In summary, the application has the following beneficial effects:

[0024] 1. Because this application uses polyether polyol, polyester polyol, and isocyanate to react and generate a polyurethane prepolymer, it provides the hot melt adhesive with better flexibility and durability. The use of tackifying resins and viscosity stabilizers enables the polyurethane hot melt adhesive to maintain good bond strength for a longer period, improving the final bond strength. The use of pentaerythritol diacrylate promotes faster and stronger bonding between the hot melt adhesive and the substrate, improving the initial tack of the hot melt adhesive.

[0025] 2. In this application, 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethylsilane, and γ-(methacryloyloxy)propyltrimethylsilane are used as coupling agents added to the polyurethane hot melt adhesive raw material. These agents react with the polyurethane prepolymer to enhance the cohesive strength and later-stage adhesion of the polyurethane hot melt adhesive. Simultaneously, adjusting the end-capping rate of the coupling agents within a suitable range can promote the polyurethane hot melt adhesive to possess both good initial and final tack strength. Detailed Implementation

[0026] The present application will be further described in detail below with reference to the embodiments.

[0027] All raw materials used in the examples are commercially available.

[0028] Example

[0029] Example 1

[0030] This embodiment provides a moisture-curing reactive polyurethane hot melt adhesive for bags and luggage, comprising the following raw materials in parts by weight: 15 kg of polyether polyol, 50 kg of polyester polyol, 35 kg of isocyanate, 1 kg of catalyst, 15 kg of tackifying resin, 4 kg of viscosity stabilizer, 2 kg of pentaerythritol diacrylate, 8 kg of additives, and 4 kg of coupling agent. The polyether polyol is polyoxypropylene polyol with a number average molecular weight of 2000; the polyester polyol is obtained by reacting adipic acid and diethylene glycol with a hydroxyl value of 20 mg KOH / g; the isocyanate is diphenylmethane diisocyanate; the catalyst is dimorpholine diethyl ether; the tackifying resin is polyacrylic acid resin; the viscosity stabilizer is erucic acid; the additives are antioxidant 1010 and leveling agent BYK-333; and the coupling agent is 3-aminopropyltriethoxysilane.

[0031] The preparation method of moisture-curing reactive polyurethane hot melt adhesive for luggage includes the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate and additives, melting and mixing at 100°C, vacuum dehydration, then adding isocyanate under nitrogen protection and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2 hours, with the coupling agent end-capping rate reaching 15%, to obtain moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0032] Example 2

[0033] The difference between Example 2 and Example 1 is that the amount of polyether polyol used in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is 10 kg, polyester polyol is 60 kg, isocyanate is 50 kg, catalyst is 1.5 kg, tackifying resin is 10 kg, viscosity stabilizer is 5 kg, pentaerythritol diacrylate is 1 kg, additives are 5 kg, and coupling agent is 3 kg.

[0034] Example 3

[0035] The difference between Example 3 and Example 1 is that the amount of polyether polyol used in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is 20 kg, polyester polyol is 40 kg, isocyanate is 20 kg, catalyst is 0.5 kg, tackifying resin is 20 kg, viscosity stabilizer is 3 kg, pentaerythritol diacrylate is 3 kg, additives are 10 kg, and coupling agent is 5 kg.

[0036] Example 4

[0037] The difference between Example 4 and Example 1 is that the coupling agent in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is γ-(2,3-epoxypropoxy)propyltrimethylsilane.

[0038] Example 5

[0039] The difference between Example 5 and Example 1 is that the coupling agent in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is γ-(methacryloyloxy)propyltrimethylsilane.

[0040] Example 6

[0041] The difference between Example 6 and Example 1 is that the viscosity stabilizer in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is polyphosphoric acid. The polyphosphoric acid was purchased from Nantong Runfeng Petrochemical Co., Ltd. under the Runfeng brand 8017-16-1.

[0042] Example 7

[0043] The difference between Example 7 and Example 6 is that the tackifying resin in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is petroleum resin. Specifically, the petroleum resin is C5 petroleum resin.

[0044] Example 8

[0045] The difference between Example 8 and Example 6 is that the tackifying resin in the wet-curing reactive polyurethane hot melt adhesive raw material for bags is disproportionated rosin resin. The disproportionated rosin resin has an acid value of 156 mg KOH / g and a softening point of 76°C.

[0046] Example 9

[0047] The difference between Example 9 and Example 8 is that the disproportionated rosin resin in the wet-curing reactive polyurethane hot melt adhesive raw material for bags has been compatibilized and modified.

[0048] The preparation method of moisture-curing reactive polyurethane hot melt adhesive for luggage includes the following specific steps:

[0049] S1: The disproportionated rosin is ground into powder beforehand, heated and melted under the protection of nitrogen, and then a modified catalyst and a polyol are added. The catalyst is zinc oxide and the polyol is pentaerythritol. The mass ratio of disproportionated rosin, modified catalyst and polyol is 1:0.1:1. The mixture is heated to 240℃ and reacted. During the reaction, the acid value is continuously measured until the acid value remains constant, thus obtaining the modified disproportionated rosin resin.

[0050] S2: Polyether polyol, polyester polyol, modified disproportionated rosin resin, viscosity stabilizer, pentaerythritol diacrylate and additives are mixed and melt-mixed at 100°C, dehydrated under vacuum, and then isocyanate is added under nitrogen protection and heated to 120°C for reaction. Finally, catalyst and coupling agent are added and reacted at 120°C for 2 hours. The coupling agent end-capping rate reaches 15%, thus obtaining a wet-curing reactive polyurethane hot melt adhesive for luggage.

[0051] Example 10

[0052] The difference between Example 10 and Example 8 is that the polyol used in the modification of disproportionated rosin resin in the urethane hot melt adhesive raw material is glycerol.

[0053] The preparation method of moisture-curing reactive polyurethane hot melt adhesive for luggage includes the following specific steps:

[0054] S1: The disproportionated rosin is ground into powder beforehand, heated and melted under the protection of nitrogen, and then a modified catalyst and a polyol are added. The catalyst is zinc oxide and the polyol is glycerol. The mass ratio of disproportionated rosin, modified catalyst and polyol is 1:0.1:1. The mixture is heated to 240℃ and reacted. During the reaction, the acid value is continuously measured until the acid value remains constant, thus obtaining the modified disproportionated rosin resin.

[0055] S2: Polyether polyol, polyester polyol, modified disproportionated rosin resin, viscosity stabilizer, pentaerythritol diacrylate and additives are mixed and melt-mixed at 100°C, dehydrated under vacuum, and then isocyanate is added under nitrogen protection and heated to 120°C for reaction. Finally, catalyst and coupling agent are added and reacted at 120°C for 2 hours. The coupling agent end-capping rate reaches 15%, thus obtaining a wet-curing reactive polyurethane hot melt adhesive for luggage.

[0056] Comparative Example

[0057] Comparative Example 1

[0058] The difference between Comparative Example 1 and Example 1 is that pentaerythritol diacrylate is not used in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for bags.

[0059] The preparation method of moisture-curing reactive polyurethane hot melt adhesive for luggage includes the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer and additives, melting and mixing at 100°C, vacuum dehydration, then adding isocyanate under nitrogen protection and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2 hours, with the coupling agent end-capping rate reaching 15%, to obtain moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0060] Comparative Example 2

[0061] The difference between Comparative Example 2 and Example 1 is that pentaerythritol diacrylate and viscosity stabilizer are not used in the raw materials of the wet-curing reactive polyurethane hot melt adhesive for bags.

[0062] The preparation method of moisture-curing reactive polyurethane hot melt adhesive for luggage includes the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin and additives, melting and mixing at 100°C, dehydrating under vacuum, then adding isocyanate under nitrogen protection and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2 hours, with the coupling agent end-capping rate reaching 15%, to obtain moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0063] Performance testing

[0064] The following performance tests were conducted on the wet-curing reactive polyurethane hot melt adhesives for bags and luggage provided in Examples 1-10 and Comparative Examples 1-2 of this application. The specific test results are shown in Table 1.

[0065] Detection methods

[0066] I. Adhesive performance

[0067] Referring to the standard FZ / T01085-2009 "Test Method for Peel Strength of Hot Melt Adhesive Lining", the initial peel strength and final peel strength of the wet-curing reactive polyurethane hot melt adhesive for bags prepared in this application were tested. The preparation method of the adhesive sample is as follows: The sample was heated to 80℃, coated onto the biomimetic fabric of the bag with a stainless steel circular mesh with a pore size of 0.45μm, and then pressed and bonded with the same material fabric by a heat press machine. Finally, it was placed in a constant temperature and humidity environment of 20℃ and 80% humidity. The peel strength was tested after 10 min and 48 h, respectively. The test results at 10 min and 48 h were defined as the initial peel strength and the final peel strength, respectively.

[0068] Table 1: Performance Test Results Data Table

[0069]

[0070] The performance test results show that the wet-curing reactive polyurethane hot melt adhesive for bags prepared in this application has good initial tack and later adhesion under the synergistic effect of various components.

[0071] A comparison between Example 6 and Example 1 shows that different viscosity stabilizers have different effects on promoting the bonding performance of polyurethane hot melt adhesives. The performance test results show that the polyurethane hot melt adhesive prepared in Example 6 has better overall performance.

[0072] As can be seen from Examples 9-10, by modifying the disproportionated rosin resin, the performance test results show that the bonding strength of the polyurethane hot melt adhesive is significantly increased, and the later bonding force is also enhanced.

[0073] A comparison of Comparative Examples 1-2 and Example 1 shows that Comparative Example 1 does not use pentaerythritol diacrylate, and Comparative Example 2 does not use pentaerythritol diacrylate and viscosity stabilizer. The performance test results show that the bonding strength of the polyurethane hot melt adhesive decreases. This further illustrates that the initial tack and later bonding strength of the hot melt adhesive formed by a single polyurethane prepolymer are both low, which cannot meet the requirements of the luggage industry.

[0074] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A moisture-curing reactive polyurethane hot melt adhesive for bags and luggage, characterized in that, The raw materials include the following parts by weight: 10-20 parts polyether polyol, 40-60 parts polyester polyol, 20-50 parts isocyanate, 0.5-1.5 parts catalyst, 10-20 parts tackifying resin, 3-5 parts viscosity stabilizer, 1-3 parts pentaerythritol diacrylate, 5-10 parts additives, and 3-5 parts coupling agent; the coupling agent has an end-capping rate of 13-17%, the viscosity stabilizer is polyphosphoric acid, and the tackifying resin is disproportionated rosin resin; the disproportionated rosin resin undergoes compatibilization modification, and the compatibilization modification method includes the following specific steps: The disproportionated rosin was preheated and melted under an inert gas atmosphere. Then, a modified catalyst and a polyol were added to form a reaction solution. The reaction solution was heated to 230-250°C and stirred until the acid value of the reaction solution remained constant. The reaction solution was then cooled to obtain the modified disproportionated rosin resin.

2. The wet-curing reactive polyurethane hot melt adhesive for bags and luggage according to claim 1, characterized in that, The coupling agent is 3-aminopropyltriethoxysilane.

3. The wet-curing reactive polyurethane hot melt adhesive for luggage and bags according to claim 1, characterized in that, The additives include antioxidants and leveling agents.

4. A method for preparing a moisture-curing reactive polyurethane hot melt adhesive for bags and luggage as described in any one of claims 1-3, characterized in that, The specific steps include: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate and additives, melting and mixing at 80-120℃, vacuum dehydration, then adding isocyanate under nitrogen protection and heating reaction, and finally adding catalyst and coupling agent to keep the reaction at a constant temperature to obtain a wet-curing reactive polyurethane hot melt adhesive for bags.

5. The preparation method of the wet-curing reactive polyurethane hot melt adhesive for bags and luggage according to claim 4, characterized in that, The reaction temperature is 100-120℃.

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